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WO2024162246A1 - Insulation sheet and method for manufacturing same, insulation fibers and method for manufacturing same, and fiber-containing suspension used to manufacture insulating sheet - Google Patents

Insulation sheet and method for manufacturing same, insulation fibers and method for manufacturing same, and fiber-containing suspension used to manufacture insulating sheet Download PDF

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Publication number
WO2024162246A1
WO2024162246A1 PCT/JP2024/002618 JP2024002618W WO2024162246A1 WO 2024162246 A1 WO2024162246 A1 WO 2024162246A1 JP 2024002618 W JP2024002618 W JP 2024002618W WO 2024162246 A1 WO2024162246 A1 WO 2024162246A1
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WIPO (PCT)
Prior art keywords
fibers
heat insulating
fiber
insulating
fine particles
Prior art date
Application number
PCT/JP2024/002618
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French (fr)
Japanese (ja)
Inventor
ラダー ウー
官益 李
和夫 小沼
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株式会社Thermalytica
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Publication of WO2024162246A1 publication Critical patent/WO2024162246A1/en

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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
    • D04H1/587—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives characterised by the bonding agents used
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
    • D06M11/77—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with silicon or compounds thereof
    • D06M11/79—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with silicon or compounds thereof with silicon dioxide, silicic acids or their salts
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
    • D21H13/36—Inorganic fibres or flakes
    • D21H13/38—Inorganic fibres or flakes siliceous
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials

Definitions

  • the present invention relates to a heat insulating sheet and a method for producing the same, a heat insulating fiber and a method for producing the same, and a fiber-containing suspension used in the production of a heat insulating sheet.
  • insulating and heat-resistant properties are attracting attention as a measure against global warming.
  • a structure is adopted in which an insulating sheet is sandwiched between adjacent cells to reduce the impact that overheating in some cells has on adjacent cells.
  • the insulating sheet sandwiched between the cells must be heat-resistant to prevent the cells from overheating and causing thermal runaway, and must also be flame-retardant and fire-resistant in case of fire.
  • the insulating sheet must be as thin as possible. In this way, insulating sheets are required to achieve the required insulating and flame-retardant properties while being as thin as possible.
  • Patent Document 1 discloses a resin-coated flame-retardant fiber yarn. It is said that the flame-retardant fiber yarn is coated with two resin coating layers, and the outer layer contains titanium dioxide particles, thereby achieving light transmission, heat insulation, and flame retardancy.
  • the manufacturing method is described as follows: A resin solution containing a titanium dioxide-free adhesive resin is applied to a glass fiber bundle, which is a flame-retardant fiber yarn, and after squeezing out the excess resin solution, the bundle is heated to form an inner resin coating layer.
  • a resin solution containing titanium dioxide is applied to the glass fiber bundle on which the inner resin coating layer has been formed, and after squeezing out the excess resin solution, the bundle is heated to form a resin layer containing titanium dioxide on the outside of the inner resin coating layer (for details, see paragraphs 0026 to 0045 of the same document). It is said that a woven fabric can be made by weaving this resin-coated flame-retardant fiber yarn as the warp and weft (ibid., paragraph 0046).
  • Patent Document 2 discloses a lightweight heat and sound insulation material with excellent heat insulation and sound insulation properties.
  • the basic structure is a cell in which an aggregate of silica aerogel particles is surrounded by a network of organic nanofibers with anionic functional groups, and a solid composite with a three-dimensional continuous structure in which multiple cells are closely spaced is formed inside a nonwoven fabric or open-cell foam, which is said to be lightweight and have excellent sound insulation properties.
  • Patent Document 3 discloses ultrafine aerogel particles, which are made from aerogel having a three-dimensional network structure in which the skeleton is formed by clusters, which are aggregates of primary particles, and which contain fine particles having a three-dimensional network structure in which the skeleton is formed by the primary particles.
  • Patent Document 3 is an invention by the inventors of the present application, and is commercially known as TIISA (a registered trademark of Thermalytica Co., Ltd.).
  • Ultrafine aerogel particles have a thermal conductivity equivalent to that of high-performance aerogel, and a bulk density of 0.01 g/cm 3 or less, which is about one-tenth or less of that of general aerogel. Therefore, they are lightweight and high-performance heat insulating materials.
  • Ultrafine aerogel particles are extremely fine particles because their skeleton is formed mainly by primary particles that constitute the secondary particles, whereas the skeleton of general aerogel is formed by secondary particles, and are characterized in that more than 50% of their volume is dispersed with a particle diameter of 0.1 ⁇ m to 1.0 ⁇ m as a mode value.
  • Patent Document 4 discloses a fiber-reinforced thermoplastic resin sheet and a glass fiber nonwoven fabric carrying silica microparticles.
  • the fiber-reinforced thermoplastic resin sheet is composed of a thermoplastic matrix resin and silica microparticles contained in the glass fibers and having an average primary particle diameter in the range of 1 to 100 nm.
  • Patent Document 5 discloses a heat insulating material that is said to have high strength and excellent heat insulating properties.
  • the heat insulating material is composed of aerogel particles, an adhesive that bonds them, and a composite adhesive in which a heat-fusible adhesive component is coated with a protective film.
  • the primary object of the present invention is to provide an insulating sheet having high insulating performance. Another object of the present invention is to further impart flame retardant performance to the insulating sheet. Yet another object of the present invention is to provide a fiber-containing suspension and insulating fibers suitable for producing such an insulating sheet.
  • the insulating sheet of the present invention is an insulating sheet containing base fibers and insulating microparticles, the base fibers are bonded to each other or woven to form a sheet body, and the insulating microparticles are present inside and/or outside the base fibers.
  • the method for manufacturing the insulating sheet according to the present invention includes the steps of dispersing insulating microparticles to prepare an insulating microparticle-containing suspension, dissolving a binder to prepare a binder solution, mixing the insulating microparticle-containing suspension, the binder solution, base fibers, and binder fibers to prepare a fiber-containing suspension, and removing liquid components from the fiber-containing suspension to form a sheet (papermaking process).
  • Another method for manufacturing a heat insulating sheet according to the present invention includes the steps of: mixing a thermoplastic resin with heat insulating particles to obtain a resin containing microparticles; storing the resin containing microparticles in a container having fine holes arranged in a chamber; rotating the container while heating it to eject the resin containing microparticles from the fine holes to obtain short fibers; and forming the short fibers into a sheet.
  • a further method for producing a heat insulating sheet according to the present invention includes the steps of melting a thermoplastic resin and mixing the melted thermoplastic resin with heat insulating microparticles to prepare a microparticle-containing resin, extruding the melted microparticle-containing resin through pores to obtain fibers, spinning the fibers to obtain yarn, and weaving and knitting the yarn.
  • the fiber-containing suspension for manufacturing the insulating sheet of the present invention is a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, base fibers, and binder fibers.
  • a fiber-containing suspension for manufacturing a heat insulating sheet is a mixture of a heat insulating microparticle-containing suspension in which heat insulating microparticles are dispersed in a solvent, a binder solution, heat insulating fibers, and binder fibers, and the heat insulating fibers are formed by bonding heat insulating microparticles for fibers to the surface of a base fiber with a binder for fibers, and the heat insulating microparticles for fibers are made of aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of their volume being dispersed with a mode of particle diameter of 0.1 ⁇ m to 1.0 ⁇ m, and the base fiber is silica fiber.
  • the insulating fiber of the present invention has insulating fine particles bonded to the surface of a base fiber by a binder, the insulating fine particles are made of aerogel having a three-dimensional mesh structure with a skeleton made of clusters that are aggregates of primary particles, the insulating fine particles have a three-dimensional mesh structure with a skeleton made of the primary particles, and 50% or more of the volume of the insulating fine particles are fine particles dispersed with a mode of particle diameter of 0.1 ⁇ m to 1.0 ⁇ m, and the base fiber is silica fiber.
  • Another insulating fiber according to the present invention has insulating microparticles present inside a matrix fiber in a state where they are at least partially embedded, the insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, the insulating microparticles have a three-dimensional mesh structure with a skeleton made up of the primary particles, and 50% or more of the volume of the insulating microparticles are microparticles dispersed with a mode of particle diameters of 0.1 ⁇ m to 1.0 ⁇ m, and the matrix fiber contains a thermoplastic resin.
  • the method for producing the insulating fiber according to the present invention is a method for producing the insulating fiber according to the present invention, and includes the steps of dispersing the insulating microparticles to prepare an insulating microparticle-containing suspension, dissolving a binder to prepare a binder solution, mixing the insulating microparticle-containing suspension and the binder solution to prepare a slurry, and depositing the slurry as an evaporation source onto the base fiber.
  • Another method for producing insulating fibers according to the present invention is the same as the method for producing insulating fibers according to the present invention, and includes the steps of dissolving a binder to prepare a binder solution, depositing the binder solution onto base fibers as an evaporation source, and mechanically coating the base fibers with insulating fine particles on the surfaces of which the binder solution has been attached by the deposition.
  • “dispersing (the fine particles)” means putting the fine particles into a liquid and dispersing them in the liquid, not dissolving them.
  • the “papermaking process (sheet formation process)” includes the process of thinly spreading a suspension containing base fibers, removing excess liquid, and then drying to form a sheet.
  • “polyvinyl alcohol” may be abbreviated to “PVA” (polyvinyl alcohol), “polyvinyl alcohol fiber” to “PVA fiber,” and “polyvinyl alcohol powder” to “PVA powder.”
  • FIG. 1 is a schematic explanatory diagram showing an example of the configuration of a heat insulating sheet according to one embodiment of the present invention.
  • FIG. 2 is an explanatory diagram showing the relationship between the lengths of the base fibers and the binder fibers.
  • FIG. 3 is an explanatory diagram showing an example of the configuration of a flame-retardant fiber formed by adhering heat insulating fine particles to the surface of a base fiber.
  • FIG. 4 is a flow chart showing an example of a method for producing a heat insulating sheet according to an embodiment of the present invention.
  • FIG. 5 is a flow chart illustrating an example of a method for producing a flame-retardant fiber according to one embodiment of the present invention.
  • FIG. 1 is a schematic explanatory diagram showing an example of the configuration of a heat insulating sheet according to one embodiment of the present invention.
  • FIG. 2 is an explanatory diagram showing the relationship between the lengths of the base fibers and the binder fibers.
  • FIG. 6 is a flow chart showing an example of a method for manufacturing a heat insulating sheet having flame retardant properties.
  • FIG. 7 is an explanatory diagram showing the structure of an ultrafine aerogel particle, which is an example of a heat insulating particle.
  • FIG. 8 is an explanatory diagram illustrating the particle size distribution of ultrafine aerogel particles, which are an example of heat insulating particles.
  • FIG. 9 is a photograph showing the results of an experiment in which glass wool coated with a flame-retardant layer containing ultrafine aerogel particles was heated with a flame.
  • FIG. 10 is an optical microscope photograph showing the results of an experiment in which glass wool coated with a flame-retardant layer containing ultrafine aerogel particles was heated with a flame.
  • FIG. 10 is an optical microscope photograph showing the results of an experiment in which glass wool coated with a flame-retardant layer containing ultrafine aerogel particles was heated with a flame.
  • FIG. 11 is an explanatory diagram showing an example of a base fiber formed by mixing a thermoplastic resin and heat insulating particles.
  • FIG. 12 is a flowchart showing an example of a method for producing a heat insulating sheet according to the eighth embodiment.
  • FIG. 13 is an explanatory diagram showing an example of the configuration of an apparatus for producing base fibers of the heat insulating sheet according to the eighth embodiment.
  • FIG. 14 is a flowchart showing an example of a method for producing a heat insulating sheet according to the ninth embodiment.
  • FIG. 15 is a schematic diagram showing an example of a known spinning apparatus.
  • FIG. 16 is a schematic diagram showing the apparatus used in the examples.
  • FIG. 17 is a scanning electron microscope (SEM) photograph showing the experimental results.
  • SEM scanning electron microscope
  • Heat insulating sheet carrying heat insulating particles (Fig. 1, Fig. 11)
  • the insulating sheet shown in this embodiment is an insulating sheet (100) including base fibers (6,300) and insulating microparticles (1, 14), in which the base fibers (6,300) are bonded to each other or woven or knitted to form a sheet body, and the insulating microparticles (1, 14) are present inside and/or outside the base fibers (6,300).
  • the heat insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of the volume being dispersed with a particle diameter of 0.1 ⁇ m or more and 1.0 ⁇ m or less as a mode.
  • a heat insulating sheet in which heat insulating particles are supported in the gaps between the base fibers bonded together by a film formed by dissolving the binder fibers ( Figure 1)
  • the base fiber is a silica fiber
  • the insulating sheet (100) includes a base fiber (6), a binder fiber (7), and a bonding agent (2, not shown in Figure 1), the base fibers are bonded to each other by a film formed by dissolving the binder fiber, and the insulating microparticles (1) are supported in the gaps between the bonded base fibers by the bonding agent.
  • the presence of the insulating microparticles on the surface of the base fiber imparts flame retardancy in addition to insulating properties, making it possible to impart flame retardancy to the entire insulating sheet.
  • “adding flame retardancy” refers to performing some kind of processing on a specific object, making that object less flammable than before the processing.
  • a heat insulating sheet formed by weaving and knitting a base material fiber carrying heat insulating particles embedded in a thermoplastic resin (FIG. 11)
  • the base fiber (300) contains a thermoplastic resin (8)
  • the heat insulating microparticles (14) are present in a state in which at least a portion of them is embedded in the thermoplastic resin (8) in the base fiber (300)
  • the sheet body is formed by weaving and knitting yarns spun from the base fiber (300).
  • the base fiber (300) is spun by a known spinning method, and the spun yarn is woven or knitted by a known method to form a sheet body, which is an insulating sheet.
  • thermoplastic resin a thermoplastic resin (8)
  • the insulating particles (14) are present in a state in which at least a portion of them is embedded in the thermoplastic resin (8) in the base fiber (300)
  • the sheet body is formed by bonding the base fibers to each other with a film formed by melting the thermoplastic resin.
  • a representative embodiment of the present invention is a method for producing a heat insulating sheet, which includes the following steps.
  • S2 A step of dissolving a binder to prepare a binder solution.
  • S3 A step of mixing the heat insulating microparticle-containing suspension, the binder solution, base fibers, and binder fibers to prepare a fiber-containing suspension.
  • Paper making process, S4) A process of removing the liquid component from the fiber-containing suspension to form a sheet body.
  • the base fiber is a silica fiber
  • the insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, and 50% or more of the volume of the microparticles are dispersed with a particle diameter of 0.1 ⁇ m or more and 1.0 ⁇ m or less as a mode.
  • a method for producing a heat insulation sheet according to another embodiment of the present invention includes the following steps.
  • thermoplastic resin and insulating microparticles are mixed to obtain a microparticle-containing resin.
  • the process involves placing the microparticle-containing resin in a container with fine holes, and rotating the container while heating it to eject the microparticle-containing resin from the fine holes to obtain short fibers.
  • a method for producing an insulating sheet in which the insulating sheet is produced by weaving or knitting staple fibers includes a step of spinning the staple fibers to obtain yarn, and a step of weaving or knitting the yarn.
  • a method for manufacturing an insulating sheet by molding short fibers In the step of molding the short fibers into a sheet in the method for manufacturing an insulating sheet of [10], the short fibers are spread into a thin film and heated to form the sheet.
  • a method for manufacturing a heat insulating sheet by weaving or knitting a heat insulating sheet from spun yarn includes the following steps.
  • a representative embodiment of the present invention is a method for producing a heat insulating sheet, which includes the following steps.
  • the heat insulating fiber has heat insulating fine particles for fiber bonded to the surface of the base fiber by a binder for fiber
  • the insulating microparticles for the fibers are made from aerogel having a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton made up of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 ⁇ m or more and 1.0 ⁇ m or less as the most frequent value, and the base fiber is silica fiber.
  • This provides a method for producing flame-retardant fibers even when the insulating microparticles are hydrophobic.
  • Fiber-containing suspension A typical embodiment of the present invention is a fiber-containing suspension for producing an insulating sheet, which is a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, base fibers, and binder fibers, used in the method for producing the insulating sheet.
  • a typical embodiment of the present invention is a fiber-containing suspension for producing an insulating sheet, which is used in the method for producing an insulating sheet, and which comprises a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, insulating fibers, and binder fibers, and the insulating fibers are formed by bonding insulating microparticles for the fibers to the surface of a base fiber with a binder for the fibers, the insulating microparticles for the fibers are made from aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are an aggregate of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 ⁇ m or more and 1.0 ⁇ m or less as a mode, and the base fiber is silic
  • This fiber-containing suspension can be provided as a raw material for the papermaking process (S4), etc.
  • a representative embodiment of the present invention is a heat insulating fiber (flame retardant fiber) (200) to which flame retardancy has been added, and is configured as follows.
  • the flame retardant fiber refers to a heat insulating fiber to which flame retardancy has been added as well as heat insulating properties.
  • the insulating particles (1) are bonded to the surface of the base fiber (6) with a binder (2).
  • the insulating microparticles are made from aerogel, which has a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, and are microparticles with a three-dimensional mesh structure with a skeleton made up of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 ⁇ m to 1.0 ⁇ m as the mode.
  • the matrix fiber is silica fiber.
  • FIG. 1 An exemplary embodiment of the present invention is an insulating fiber (300) constructed as follows.
  • the heat insulating particles (14) are present in a state where they are at least partially embedded inside the base fiber (300),
  • the heat insulating fine particles (14) are made from an aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 ⁇ m or more and 1.0 ⁇ m or less
  • the matrix fiber (300) comprises a thermoplastic resin (8).
  • a manufacturing method for imparting high flame retardancy to base fibers by depositing insulating fine particles (ultrafine aerogel particles) contained in the slurry onto the surface of the base fibers.
  • This provides another manufacturing method for imparting flame retardancy to matrix fibers.
  • insulating particles (ultrafine aerogel particles) to be more efficiently bonded to the surface of the silica fiber, which is the base fiber.
  • This provides a method for producing flame-retardant fibers even when the insulating microparticles are hydrophobic.
  • Fig. 1 is a schematic explanatory diagram showing an example of the structure of the heat insulating sheet of the present invention.
  • the heat insulating sheet 100 of the present invention contains base material fibers 6, binder fibers 7, and a binder (2, not shown in Fig. 1), the base material fibers 6 are bonded to each other by a film (not shown in Fig. 1) formed by dissolving the binder fibers 7, and heat insulating particles 1 are carried in the gaps between the bonded base material fibers 6.
  • the reference numeral 3 will be described later and in more detail in embodiments 4 and 5.
  • binder fiber 7 for example, polyvinyl alcohol (PVA) fiber, polyester fiber, polyester composite fiber, acrylic fiber, acrylic fiber, nylon, polyurethane fiber, polycarbonate fiber, etc. can be used.
  • PVA polyvinyl alcohol
  • the binding agent polyvinyl alcohol (PVA) powder, methyl cellulose, starch paste, gum arabic paste, etc. can be used.
  • the length of the binder fiber 7 is preferably several tens of micrometers.
  • the matrix fiber 6 is, for example, silica fiber, and is several tens of millimeters longer than the binder fiber 7. While the matrix fiber 6 extends in a plane (horizontal direction in FIG. 1), the binder fiber 7 plays a role in connecting the matrix fiber 6 vertically (thickness direction of the heat insulating sheet 100).
  • the matrix fiber 6 and the binder fiber 7 are bonded to each other by a film (not shown in FIG. 1) formed by melting, and gaps are formed in the bonded matrix fiber 6, in which the heat insulating particles 1 are supported.
  • PVA fiber which is an example of the binder fiber 7, melts and becomes a film when heated to 65°C to 85°C in a water-wet state.
  • Melt refers to dissolving in water, not melting due to heat.
  • Matrix fibers 6 such as silica fiber have mechanical strength, but heat is conducted along the fibers, so heat insulating performance cannot be expected.
  • the base material fibers 6 are long and extend in a direction parallel to the front and back surfaces of the sheet, providing the heat insulating sheet 100 with mechanical strength in the planar direction.
  • the heat insulating particles 1 are supported in the gaps between the base material fibers 6 as shown in FIG. 1, thereby providing the heat insulating sheet 100 with heat insulating performance in the thickness direction.
  • binder fiber 7 In general, insulation sheets are required to have better insulation performance in the thickness direction than in the in-plane direction. For this reason, binder fibers that reach from one surface of the insulation sheet to the other surface are not preferred.
  • the thermal conductivity of binder fibers is higher than that of silica fibers, which are often used as base fibers, so if binder fibers reach from one surface to the other surface of the insulation sheet in the thickness direction, heat will be conducted through the binder fibers, which will act to reduce the insulation performance in the thickness direction.
  • the length of the binder fibers should preferably be at most a few mm, which is approximately the same as the thickness of the insulation sheet.
  • the appropriate minimum length of the binder fiber 7 is 10 ⁇ m to several tens of ⁇ m.
  • Figure 2 is an explanatory diagram showing the relationship between the lengths of the base material fibers 6 and the binder fibers 7. When the base material fibers 6 are adjacent to each other so as to be in contact with each other (a), the binder fibers 7 are required to have a length equal to or greater than the diameter of the base material fibers 6 in order to bond the adjacent base material fibers 6.
  • the minimum length of the binder fibers 7 required is one to several times the distance between the base material fibers 6 to be connected. That is, when two fibers are connected (b), it is about the same as the distance between the base material fibers 6, when three fibers are connected in a straight line (c), it is about twice the distance between the base material fibers 6, and when three fibers are connected in a stitching manner (d), it is about three to four times the distance between the base material fibers 6.
  • the diameter of silica fibers which are generally used as base fibers, is 8 ⁇ m to 12 ⁇ m according to measurements by the inventors, so the minimum value is set to be within several times this value. Note that the minimum value mentioned here does not mean that there are no binder fibers shorter than this length, but simply means that binder fibers shorter than this length have a small contribution to the purpose of bonding the base fibers.
  • the strength and heat insulating performance can be adjusted by appropriately designing the length of the base fiber 6 and the binder fiber 7.
  • the insulating fine particles 1 it is preferable to use the ultrafine aerogel particles described in Patent Document 3.
  • Figure 7 is an explanatory diagram showing a comparison of the structures of general aerogel fine powder and ultrafine aerogel particles whose skeleton is formed by primary particles.
  • the three-dimensional mesh structure of general aerogel fine powder 13 is composed of units of secondary particles 12, which are clusters of primary particles 11 ( Figure 7(a)), whereas ultrafine aerogel particles 14 have a three-dimensional mesh structure formed with the primary particles 11 as the skeleton ( Figure 7(b)).
  • Aerogels that are generally available are granules that have a three-dimensional mesh structure with a skeleton consisting of secondary particles 12 as units, so even if they are finely crushed using a crushing device, the skeleton structure does not change.
  • Figure 8 is an explanatory diagram showing an example of the frequency distribution of particle sizes for aerogel granules, aerogel powder, aerogel fine powder, and aerogel ultrafine particles, which are fine particles with a skeleton formed by primary particles, in order from the bottom.
  • the aerogel granules are the aerogel granules that are generally available.
  • the aerogel powder is an aerogel powder produced by crushing aerogel granules at 5000 to 7000 rpm for 2 minutes using a Spin Mix Homogenizer SX08 manufactured by Mitsui Electric Seiki Co., Ltd.
  • the aerogel fine powder is a fine powder produced by crushing aerogel granules at 21000 rpm for 20 seconds using a STEALTH885 manufactured by Blendtec Co., Ltd., in an attempt to further reduce the particle size.
  • the horizontal axis of Figure 8 is the particle size, and the vertical axis is the frequency distribution of the relative particle amount.
  • the right vertical axis shows the frequency, and the left vertical axis shows the cumulative value.
  • Figure 8 shows the results of observations made using a laser diffraction particle size distribution (PSD) measurement device.
  • PSD laser diffraction particle size distribution
  • Figure 8 shows the particle size distribution measured using a laser diffraction particle size distribution measurement device SALD-2300 manufactured by Shimadzu Corporation.
  • Particle size distribution is an index that shows what size (particle diameter) of particles is contained in the sample particle group to be measured and what the ratio (relative particle amount with the total being 100%) is, and the dimension (order) of the particle amount is based on volume.
  • aerogel granules have only one peak in relative particle amount with an average particle size of about 400 ⁇ m (bottom row of Figure 8).
  • the aerogel powder has an average particle size of about 90 ⁇ m
  • the aerogel fine powder has an average particle size of about 50 ⁇ m, but each has one peak in relative particle amount (third and second rows).
  • ultrafine aerogel particles have a first peak with an average particle size of about 20 ⁇ m and a second peak with an average particle size of about 0.3 ⁇ m, and the relative particle amount of the first peak with an average particle size of about 20 ⁇ m is 21.2%, and the second peak with an average particle size of about 0.3 ⁇ m is 78.8%.
  • the first peak with an average particle size of approximately 20 ⁇ m
  • the second peak with an average particle size of approximately 0.3 ⁇ m
  • the first peak is composed of fine particles with a three-dimensional mesh structure whose skeleton is made up of primary particles
  • the second peak with an average particle size of approximately 0.3 ⁇ m
  • General aerogel has a three-dimensional mesh structure whose skeleton is made up of secondary particles, so no matter how high the grinding conditions are, it is difficult to produce fine particles with a particle size of 10 ⁇ m or less.
  • it is necessary to fundamentally change the manufacturing method such as significantly changing not only the grinding conditions but also the aging conditions, unlike the normal aerogel manufacturing process.
  • the heat insulating fine particles 1 are preferably the aerogel ultrafine particles described above, that is, heat insulating fine particles made of aerogel having a three-dimensional mesh structure with a skeleton formed of clusters that are aggregates of primary particles 11, having a three-dimensional mesh structure with a skeleton formed of the primary particles, and having a mode of particle diameters of 0.1 ⁇ m to 1.0 ⁇ m for 50% or more of the volume.
  • silica fiber is preferable as the base fiber 6
  • PVA fiber is preferable as the binder fiber
  • PVA is preferable as the bonding agent.
  • silica fiber which is a typical base fiber 6, has a thickness of about 10 ⁇ m, so it is not a size relationship that allows aerogel granules of several hundred ⁇ m to be supported in the gaps of the base fiber, and aerogel ultrafine particles of 1 ⁇ m or less are preferable to form a structure that supports them in the gaps.
  • the thermal conductivity can be improved from approximately 40 mW/mK to less than 30 mW/mK by using ultrafine aerogel particles as the insulating particles 1.
  • the number of particles aligned in the thickness direction is small when the sheet is made thin, and the contribution of the shells of the particles to heat conduction is large
  • ultrafine aerogel particles have an extremely small particle diameter, so when the sheet is made thin, the gaps (voids) are larger than the particles in the thickness direction, and the heat conduction by the shells of the particles is small. Furthermore, the voids impede air convection, improving the insulating performance.
  • heat insulating sheet 100 it is preferable to adhere heat insulating particles 1 to the surface of the base fiber 6 with a binder 2. This imparts flame retardancy as well as heat insulating properties to the base fiber 6, and makes the entire heat insulating sheet 100 flame retardant.
  • FIG 3 is an explanatory diagram showing an example of the configuration of a flame-retardant fiber 200 (insulating fiber with added flame retardancy) formed by adhering insulating fine particles 1 to the surface of a base fiber 6. It is more reliable to form a flame-retardant layer 3 containing insulating fine particles 1 so as to cover the entire surface of the base fiber 6, but it has been found that the effect of increasing flame retardancy can be achieved even when the flame-retardant layer 3 is formed in islands as shown in Figure 3. For example, when ultrafine aerogel particles are used as the insulating fine particles 1, it is possible to add flame retardancy to the extent that the surface of the insulating sheet 100 will not burn even if it is heated with a high-temperature flame exceeding 1000°C. Details will be explained in embodiments 3 to 5 and the examples.
  • FIG. 4 is a flow chart showing an example of a method for manufacturing a heat insulating sheet according to one embodiment of the present invention.
  • the method for manufacturing the heat insulating sheet 100 includes the following steps:
  • “disperse (fine particles)” means to put the fine particles in a liquid (medium) and disperse them by stirring, not to dissolve them.
  • the heat insulating fine particles 1 are hydrophobic, they are dispersed in alcohol, and if they are hydrophilic, they are dispersed in water.
  • the heat insulating fine particles 1 are ultrafine aerogel particles whose surfaces are modified with trimethylsiloxy groups or other hydrophobic groups, they show strong hydrophobicity and have high affinity with alcohol (e.g., ethanol), so alcohol is preferably used as the medium in the first step (S1).
  • PVA powder is suitable as the binder.
  • Third step (S3) The insulating microparticle-containing suspension prepared in the first step (S1), the binder solution prepared in the second step (S2), base material fibers 6, and binder fibers 7 are mixed together to prepare a fiber-containing suspension.
  • the "sheeting" in the fourth step (S4) is a process similar to papermaking (a process in the manufacturing method of Japanese paper), in which liquid components are removed from the suspension and the solid components in the suspension are left in a thin film to form a sheet. More specifically, by passing the fiber-containing suspension in the third step (S3) through a liquid-permeable mesh, the liquid (medium) passes through and the matrix fibers 6 and binder fibers 7 remain on the mesh. The remaining matrix fibers 6 and binder fibers 7 are entangled with each other and are wet with a liquid containing heat insulating fine particles 1 and a binder.
  • the matrix fibers 6 are longer than the binder fibers 7 and spread along the mesh, while the binder fibers 7 are shorter and are sandwiched between the matrix fibers 6.
  • the matrix fibers 6 and binder fibers 7 are entangled and spread over the mesh, and the heat insulating fine particles 1 and binder solution are held in the gaps.
  • peeled off from the mesh it becomes a sheet.
  • the sheet is pressed vertically as is or multiple sheets are stacked together to squeeze out excess liquid, and then dried to produce a nonwoven fabric, i.e., the heat insulating sheet 100 of this embodiment 1.
  • the surfaces of the binder fibers 7 melt in part or in whole, forming a film that bonds with the adjacent base fibers 6.
  • the binder fibers 7 are PVA fibers, it is recommended to dry them at 65°C to 85°C.
  • the fiber-containing suspension prepared in the fourth step (S4) contains the binder solution from the second step (S2), so the binder continues to function even after drying, supporting the insulating microparticles 1 so that they do not fall out of the gaps between the base fibers 6.
  • This provides a method for manufacturing the insulating sheet 100 of embodiment 1.
  • the concentration of the insulating microparticles 1 in the first step (S1) is, for example, 0.1 to 0.5 wt%
  • the concentration of the polyvinyl alcohol in the second step (S2) is, for example, 0.075 g/dl
  • the contents of the base fibers 6 and binder fibers 7 in the fiber-containing suspension are, for example, 0.5 wt% and 0.025 wt%, respectively.
  • the content of insulating microparticles 1 in the suspension containing insulating microparticles should be as high as possible while still allowing uniform dispersion in the liquid.
  • the content of insulating microparticles 1 should be limited to the amount at which they do not aggregate, and an appropriate amount of medium should be added. If the amount of medium added is too small, the insulating microparticles 1 in the suspension will aggregate and form clusters, and will not disperse uniformly. On the other hand, if the amount of medium is too large, the content of insulating microparticles 1 per unit volume will decrease, so there is a trade-off. Optimize the design through experiments, etc.
  • the strength of the sheet for example the tensile strength, can be increased by increasing the content of matrix fibers 6. Also, the sheet can be further strengthened by increasing the content of binder fibers 7, but this comes at the expense of thermal insulation performance.
  • this flame-retardant fiber can be produced by bonding heat insulating fine particles 1 to the surface of the base fiber 6 with a binder. If this flame-retardant fiber is used as the base fiber in embodiments 1 and 2, flame retardancy can be imparted to the heat insulating sheet 100. In this case, ultrafine aerogel particles are particularly suitable as the heat insulating fine particles 1.
  • silica aerogel which is a high-purity silicon dioxide
  • the particles retain the flame retardancy of silica.
  • the diameter is about 8 ⁇ m to 12 ⁇ m
  • the particle diameter of conventional aerogel fine powder is several tens of ⁇ m to several hundreds of ⁇ m as explained with reference to FIG. 8, so that it cannot be bonded in such a manner that it adheres to the surface of the silica fiber.
  • the linear particle diameter of the aerogel ultrafine particles is mostly distributed in the range of 0.3 ⁇ m to 0.7 ⁇ m, so that it can be adhered to the surface of the silica fiber.
  • the flame retardant layer 3 containing the insulating fine particles 1 are more reliable to form the flame retardant layer 3 containing the insulating fine particles 1 so as to cover the entire surface of the matrix fiber 6, but the flame retardancy can also be increased by forming the flame retardant layer 3 in an island shape as shown in FIG. 3.
  • the insulating fine particles 1 are preferably aerogel ultrafine particles. However, this is not limited to this. Any fine particles that are flame retardant and have a particle size that is sufficiently smaller than the diameter of the base fiber will suffice.
  • FIG. 5 is a flow chart showing an example of a method for producing a flame-retardant fiber according to one embodiment of the present invention. A method for producing a flame-retardant fiber according to embodiment 3 will be described ...
  • the method for producing a flame-retardant fiber by vapor-depositing insulating microparticles 1 onto the surface of a base fiber 6 includes the following steps:
  • the binder is preferably, for example, PVA powder, which is added to water at room temperature, heated to about 80°C, stirred to dissolve, and then returned to room temperature.
  • the base fiber 6 may be in any form such as a sheet, blanket, pad, or cotton, or may be in a defibrated state.
  • the deposition in the fourth step (S14) is preferably ultrasonic deposition or heat deposition. This allows the insulating fine particles 1 to be adhered to the surface of the base fiber 6 more efficiently.
  • “more efficiently” means that a large amount of insulating fine particles 1 can be adhered with a small amount of consumption.
  • a step of spraying the slurry prepared in the third step (S13) or immersing the sheet-like or blanket-like base fiber 6 and then pulling it up and drying it can also be adopted.
  • the insulating fine particles exhibit strong hydrophobicity when their surfaces are modified with trimethylsiloxy groups or other hydrophobic groups, but have a high affinity for alcohol (e.g., ethanol), so ethanol was used as the medium in the first step (S1).
  • the fine particles can be any material other than ultrafine aerogel particles that exhibits heat resistance and hydrophobicity, and since hydrophobic fine particles generally have a high affinity for alcohol and can be uniformly dispersed, other heat-resistant hydrophobic fine particles and a suitable medium may be used instead.
  • the insulating fine particles (ultrafine aerogel particles) are hydrophilic, there is no need to use alcohol (ethanol), and water can be used as the medium in the first step (S1).
  • the mixing ratio of water, alcohol (e.g. ethanol), fine particles, and binder (e.g. PVA) in the prepared slurry is optimized through experiments etc. according to the desired specifications. For example, increasing the amount of PVA as a binder increases the adhesion of the fine particles but tends to decrease flame retardancy.
  • the method for producing a flame-retardant fiber in which insulating microparticles 1 are powdered onto the surface of the base fiber 6 includes the following steps:
  • a suitable binder is, for example, PVA powder.
  • the PVA powder is added to water at room temperature, heated to about 80°C, stirred to dissolve, and then returned to room temperature.
  • Mechanismally applying refers to mixing and stirring the heat insulating fine particles 1 while the surfaces of the base material fibers 6 are wet, i.e., while the evaporated binder solution is not yet dry, to cause the heat insulating fine particles 1 to adhere to the surfaces of the base material fibers 6 wet with the binder solution.
  • An alternative manufacturing method is provided for imparting flame retardancy to matrix fibers.
  • the flame-retardant fiber can be manufactured by either manufacturing method (a) in which the insulating fine particles 1 are vapor-deposited onto the surface of the base fiber 6, or manufacturing method (b) in which the insulating fine particles 1 are powdered onto the surface of the base fiber 6.
  • manufacturing method (a) in which the insulating fine particles 1 are vapor-deposited onto the surface of the base fiber 6, or manufacturing method (b) in which the insulating fine particles 1 are powdered onto the surface of the base fiber 6.
  • aerogel ultrafine particles are particularly suitable as the insulating fine particles 1 in this case.
  • a flame retardant layer 3 containing insulating fine particles 1 is formed on the surface of a matrix fiber 6.
  • the flame retardant layer 3 containing insulating fine particles 1 may be formed so as to cover the entire surface of the matrix fiber 6, but forming the flame retardant layer 3 in an island shape as shown in Fig. 3 also has the effect of enhancing flame retardancy.
  • This section describes a method for manufacturing a flame-retardant heat insulating sheet 100.
  • Figure 6 is a flow chart showing an example of a method for manufacturing a flame-retardant insulating sheet.
  • the following steps are carried out in order to construct a heat insulating sheet 100 similar to that described in the first and second embodiments, using flame-retardant fiber 200 as base fiber 6, which is manufactured by manufacturing method (a) of vapor-depositing heat insulating microparticles 1 on the surface of base fiber 6 shown in embodiment 4, or manufacturing method (b) of powdering heat insulating microparticles 1 on the surface of base fiber 6.
  • the suspension containing heat insulating particles may be the same as the suspension containing heat insulating particles prepared in the first step (S11), or the content of the heat insulating particles 1 may be optimized in consideration of the papermaking step (eleventh step, S24).
  • Tenth step (S23) The flame-retardant fiber 200, binder fiber 7, the second insulating microparticle-containing suspension for fibers prepared in the eighth step (S21), and the second binder solution for fibers prepared in the ninth step (S22) are mixed together to prepare a fiber-containing suspension.
  • the insulating microparticles 1 can be ultrafine aerogel particles
  • the matrix fibers 6 can be silica fibers
  • the binder can be polyvinyl alcohol.
  • the insulating sheet 100 can be constructed as in the first and second embodiments. As shown in the third embodiment, the flame-retardant layer 3 can be bonded to the base fiber 6 to obtain the flame-retardant fiber 200. Furthermore, by using this flame-retardant fiber as the base fiber 6, flame retardancy can be added to the insulating sheet 100. This makes it possible to realize an insulating sheet that is not only insulating but also heat-resistant and flame-retardant, and can withstand high-temperature flames of 1000°C or more. Such an insulating sheet can be used to shield adjacent battery cells or battery modules in a battery composed of a large number of accumulated battery cells, thereby preventing thermal runaway.
  • FIG. 11 Another embodiment of the heat insulating sheet according to the present invention will be described.
  • the difference from the heat insulating sheet 100 shown in FIG. 1 is that, as shown in FIG. 11, at least a part of the heat insulating fine particles 14 is embedded in the matrix fiber 300 constituting the heat insulating sheet.
  • the matrix fiber 300 is a fiber made of a thermoplastic resin 8, and the heat insulating fine particles 14 are mixed and present in the thermoplastic resin 8.
  • the heat insulating fine particles 14 may be present on the surface of the matrix fiber 300 with a part of the heat insulating fine particles 14 exposed from the thermoplastic resin 8.
  • the particle diameter of the heat insulating fine particles 14 is sufficiently smaller than the diameter of the matrix fiber 300, or when the amount of the heat insulating fine particles 14 is relatively small compared to the amount of the thermoplastic resin 8, the heat insulating fine particles 14 may be completely embedded in the thermoplastic resin 8 and no heat insulating fine particles 14 may be present on the surface of the matrix fiber 300.
  • Thermoplastic resins include, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), aromatic polyesters mainly composed of polyalkylene terephthalate, aliphatic polyesters such as polylactic acid, polyesters such as polylactic acid, as well as known thermoplastic resins that can be used as materials for chemical fibers, such as polyamide, polyurethane, polyolefin, etc. These thermoplastic resins can be used alone or in a mixture of two or more types.
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • aromatic polyesters mainly composed of polyalkylene terephthalate aromatic polyesters mainly composed of polyalkylene terephthalate
  • aliphatic polyesters such as polylactic acid
  • polyesters such as polylactic acid
  • thermoplastic resins that can be used as materials for chemical fibers, such as polyamide, polyurethane, polyolefin, etc.
  • thermoplastic resin made by remelting thermoplastic resin molded products such as PET bottles and molding them into pellets or powder may be used as the thermoplastic resin.
  • the heat insulating sheet of this embodiment is constructed by weaving and knitting threads spun from the base fiber 300.
  • the base fiber 300 can be spun by any known spinning method described below.
  • the yarns may also be woven or knitted in any known manner.
  • "woven” refers to weaving yarns to form a woven fabric, or knitting yarns to form a knitted fabric.
  • Woven fabrics include any known weaves, such as plain, twill, satin, amundsen, and double weave.
  • Knitted fabrics include any known knitted fabrics, such as jersey, smooth, half, and double raschel.
  • the insulating sheet of this embodiment is made by weaving and knitting yarn in which insulating particles 14 are mixed into the base fiber 300, so a highly insulating sheet can be obtained without the insulating particles 14 being supported by a binder.
  • the heat insulating sheet of this embodiment uses the same base material fiber as the base material fiber 300 shown in the above-mentioned embodiment 6. That is, the base material fiber contains a thermoplastic resin, the heat insulating fine particles are present in a state where at least a part of them is embedded in the thermoplastic resin of the base material fiber, and the sheet body is a heat insulating sheet formed by bonding the base material fibers to each other with a film formed by melting the thermoplastic resin.
  • the base fiber in this embodiment contains a thermoplastic resin and can be easily melted by heat, etc., so that the base fibers can be bonded together with a film made by melting the thermoplastic resin and formed into a sheet without using binder fibers. Also, as in embodiment 6, insulating fine particles are mixed into the base fiber, so a highly insulating sheet can be obtained without carrying the insulating fine particles with a binder.
  • the matrix fibers of this embodiment may be used as a substitute for the matrix fibers of embodiment 1 to produce an insulating sheet by the manufacturing method of embodiment 2. That is, fibers in which at least some of the insulating microparticles are embedded in a thermoplastic resin are used as the matrix fibers, and the insulating sheet is produced by a papermaking process using PVA fibers, a binder, and a suspension containing the insulating microparticles. Since the matrix fibers contain the insulating microparticles, higher insulating performance can be obtained.
  • the manufacturing method of this embodiment can also be cited as an example of a method for manufacturing the heat insulating sheets shown in the above-mentioned embodiments 6 and 7. As illustrated in FIG. 12, the manufacturing method of the heat insulating sheet of this embodiment includes the following steps.
  • Twelfth step (S25) A step of mixing a thermoplastic resin and heat insulating fine particles to obtain a fine particle-containing resin.
  • thermoplastic resin is heated and melted, and the insulating microparticles are added thereto, and the mixture is stirred and mixed while being heated to prepare a microparticle-containing resin.
  • the resin may then be crushed and placed in the container and melted again. This allows the insulating microparticles in the thermoplastic resin to be dispersed relatively uniformly.
  • the microparticle-containing resin may be obtained by placing the molten thermoplastic resin and the insulating microparticles together in a container or the like. In this case, the thermoplastic resin and the insulating microparticles are not completely mixed together to form the microparticle-containing resin.
  • step 13 the microparticle-containing resin 9 obtained in step 12 is placed in a container 400 with fine holes arranged in chamber C, and while the container 400 is heated, motor M is driven to rotate the container, causing the microparticle-containing resin 9 to be ejected from the fine holes in the container 400 by centrifugal force, and the resin is sprayed against the inner wall of chamber C to obtain short fibers.
  • the microparticle-containing resin may be obtained by directly putting the molten thermoplastic resin and the insulating microparticles together into the container with fine holes used in step 13. In this case, steps 12 and 13 are carried out simultaneously.
  • the container is connected to motor M by a rotating shaft 401, and is rotatable around the rotating shaft 401 by driving motor M.
  • the side wall of container 400 has a number of fine holes that connect the inside and outside of the container.
  • the container 400 is heated by heater H installed below to melt the microparticle-containing resin 9 inside, and in this state, motor M is driven to rotate it. Centrifugal force due to rotation acts on the microparticle-containing resin 9 inside container 400, and the microparticle-containing resin 9 is rapidly cooled and turned into fibers by being ejected from the fine holes in container 400, and is sprayed in the form of short fibers onto the inner wall of chamber C.
  • the short fibers sprayed onto the inner wall of chamber C become fibers (cotton-like fibers) 500 in which the short fibers are entangled with each other.
  • the obtained short fibers 500 are formed into a sheet. Since the short fibers contain a thermoplastic resin, they can be easily deformed by heating. Therefore, for example, the cotton-like fibers can be easily formed into a sheet by heating and forming them into a sheet. Alternatively, such short fibers can be spun by a known spinning method as in embodiment 6, and woven and knitted into yarn to form a sheet.
  • a manufacturing method of this embodiment can also be cited as an example of a method for manufacturing the heat insulating sheet shown in embodiment 6 above.
  • a manufacturing method of a heat insulating sheet according to yet another embodiment of the present invention includes the following steps, as illustrated in FIG. 14.
  • Step 15 can be performed in the same manner as step 12 of embodiment 8 (S25 in FIG. 12).
  • step 16 the molten microparticle-containing resin is extruded through the pores to obtain fibers.
  • Methods for obtaining fibers by extrusion include, for example, a method in which molten microparticle-containing resin 601 is extruded into a cooling atmosphere (by blowing cold air) using a spinning device 600 as shown in FIG. 15 to form multiple fibers, which are then twisted and spun (melt spinning method), a method in which microparticle-containing resin is extruded into a solidifying liquid rather than a cooling atmosphere (wet spinning method), and a method in which microparticle-containing resin is extruded into a heated atmosphere rather than a cooling atmosphere (dry spinning method).
  • Steps 17 and 18 can be carried out in the same manner as in embodiment 6.
  • Example 1 As explained in the fourth and fifth embodiments, ultrafine aerogel particles were adhered to glass wool, which is a silica fiber, to form a flame-retardant layer, and the flame-retardant layer was compared with glass wool that did not have a flame-retardant layer.
  • Samples of the same thickness were cut out from a single glass wool blanket to create a glass wool blanket sample without a flame-retardant layer and a glass wool blanket sample with a flame-retardant layer.
  • One side was heated with a Coleman mini torch 170-9105 for 60 seconds over a 1300°C flame, and the heated side and the opposite side were observed with the naked eye and an optical microscope.
  • Figure 9 is a photograph of the actual product.
  • the glass wool blanket sample without a flame-retardant layer has melted on the surface that was heated by the flame (hot side), and the opposite surface (cold side) has also been observed to have thinned in the center where it was heated.
  • the glass wool blanket sample with a flame-retardant layer has a dent observed on the surface that was heated by the flame (hot side), but there is no change on the opposite surface (cold side).
  • Figure 10 is an optical microscope photograph. It can be seen that the fibers have melted in the area of the glass wool blanket sample (left side) that does not form a flame-retardant layer, but the glass wool blanket sample (right side) that does form a flame-retardant layer shows almost no change from before it was heated by the flame.
  • Example 2 The staple fibers used in the method for producing a heat insulating sheet shown in embodiment 8 were produced by the following method. (Material amount) Cut pieces of PET bottles Ultrafine aerogel particles (product name: TIISA, manufactured by Thermalytica Inc.) (Method of producing fine particle-containing resin) The cut pieces of the PET bottle and ultrafine aerogel particles were placed in a stainless steel cup and stirred while being heated with an alcohol lamp until the pieces of the PET bottle were completely melted. Heating was then stopped and the mixture was cooled to room temperature to obtain a resin containing fine particles.
  • Ultrafine aerogel particles product name: TIISA, manufactured by Thermalytica Inc.
  • the content of ultrafine aerogel particles in the fine particle-containing resin was adjusted to 1 mass %, 3 mass %, 4 mass %, and as a control, no ultrafine aerogel particles (0 mass %).
  • the cooled fine particle-containing resin was hit with a hammer to break up lumps. (Method of Producing Short Fibers)
  • a small hole was drilled in the side of a 350 ml aluminum beverage bottle, and the bottle was set in the apparatus shown in Figure 16. The size of the small hole was 2 mm.
  • the present invention can be suitably used for heat insulating sheets and manufacturing methods thereof, heat insulating fibers and manufacturing methods thereof, and fiber-containing suspensions used in the manufacture of heat insulating sheets.
  • Heat insulating fine particles e.g., ultrafine aerogel particles
  • Binder e.g., PVA
  • Flame retardant layer Binder layer 6
  • Base fiber e.g., silica fiber
  • Binder fiber e.g., PVA fiber
  • Thermoplastic resin Microparticle-containing resin 11
  • Primary particle Secondary particle (aggregate of primary particles, cluster)
  • Aerogel fine powder (powder with a skeleton formed by secondary particles)
  • Fine particles whose skeleton is formed by primary particles e.g., ultrafine aerogel particles
  • 100 Heat insulating sheet 200 Flame retardant fiber 300
  • Flame retardant fiber 300
  • Base fiber e.g., silica fiber

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Abstract

This insulation sheet includes matrix fibers and insulating microparticles, wherein: the matrix fibers are mutually bonded or interlaced to form a sheet body; and the insulating microparticles are present in the interior and/or on the outer side of the matrix fibers. In one embodiment, the insulation sheet includes matrix fibers, binder fibers, and a binding agent, wherein: the matrix fibers are mutually bonded by a film formed as the binder fibers melt; and insulating microparticles are supported by the binding agent in gaps between the bonded matrix fibers. These insulation fibers are present in in the interior of matrix fibers in a state in which at least a portion of the insulating microparticles are embedded. The insulating microparticles are formed with, as a raw material, an aerogel having a three-dimensional mesh structure, the framework of which is formed of clusters that are aggregates of primary particles, and have a three-dimensional mesh structure, the framework of which is formed of the primary particles. The particle diameters of at least 50% of the volume of said microparticles vary so that the mode is found between 0.1 μm and 1.0 μm. The matrix fibers include a thermoplastic resin.

Description

断熱シート及びその製造方法、断熱繊維及びその製造方法、並びに断熱シートの製造に用いられる繊維含有懸濁液Heat insulating sheet and its manufacturing method, heat insulating fiber and its manufacturing method, and fiber-containing suspension used for manufacturing heat insulating sheet
　本発明は、断熱シート及びその製造方法、断熱繊維及びその製造方法、並びに断熱シートの製造に用いられる繊維含有懸濁液に関する。 The present invention relates to a heat insulating sheet and a method for producing the same, a heat insulating fiber and a method for producing the same, and a fiber-containing suspension used in the production of a heat insulating sheet.
　地球温暖化対策として、断熱性能や耐熱性能を発揮する素材が注目されている。例えば、多数の電池セルが集積されている電池では、一部のセルの過熱が隣接するセルに及ぼす影響を抑えるために、隣接するセル間に断熱シートを挟む構造が採用される。このときセルの過熱が進行して熱暴走するのを防ぐために、挟まれる断熱シートには耐熱性が求められ、さらには発火する場合に備えて難燃性や耐火性が求められる。一方、電池の体積当たりの蓄電量を高めるためには、断熱シートにできるだけ薄いことが求められる。このように断熱シートは、要求される断熱性、難燃性をできるだけ薄く実現することが求められている。 Materials that exhibit insulating and heat-resistant properties are attracting attention as a measure against global warming. For example, in batteries that have many integrated battery cells, a structure is adopted in which an insulating sheet is sandwiched between adjacent cells to reduce the impact that overheating in some cells has on adjacent cells. In this case, the insulating sheet sandwiched between the cells must be heat-resistant to prevent the cells from overheating and causing thermal runaway, and must also be flame-retardant and fire-resistant in case of fire. On the other hand, to increase the amount of electricity stored per volume of a battery, the insulating sheet must be as thin as possible. In this way, insulating sheets are required to achieve the required insulating and flame-retardant properties while being as thin as possible.
　特許文献１には、樹脂被覆難燃性繊維糸が開示されている。難燃性繊維糸を２層の樹脂被膜層で被覆し、外側の層に二酸化チタン粒子を含むことにより、透光性、遮熱性及び難燃性を実現しているとされる。その製造方法については、以下のように説明されている。難燃性繊維糸であるガラス繊維束に、二酸化チタンを含まない接着用の樹脂を含む樹脂溶液を塗り、余分な樹脂溶液を絞った後に加熱して、内側の樹脂被膜層を形成する。次に、内側の樹脂被膜層が形成されたガラス繊維束に、二酸化チタンを含む樹脂溶液を塗り、余分な樹脂溶液を絞った後に加熱して、内側の樹脂被膜層の外側に二酸化チタンを含む樹脂層を形成する（詳しくは、同文献の第００２６段落～第００４５段落）。この樹脂被覆難燃性繊維糸を経糸と緯糸として織り、織物を造ることができるとされる（同、第００４６段落）。 Patent Document 1 discloses a resin-coated flame-retardant fiber yarn. It is said that the flame-retardant fiber yarn is coated with two resin coating layers, and the outer layer contains titanium dioxide particles, thereby achieving light transmission, heat insulation, and flame retardancy. The manufacturing method is described as follows: A resin solution containing a titanium dioxide-free adhesive resin is applied to a glass fiber bundle, which is a flame-retardant fiber yarn, and after squeezing out the excess resin solution, the bundle is heated to form an inner resin coating layer. Next, a resin solution containing titanium dioxide is applied to the glass fiber bundle on which the inner resin coating layer has been formed, and after squeezing out the excess resin solution, the bundle is heated to form a resin layer containing titanium dioxide on the outside of the inner resin coating layer (for details, see paragraphs 0026 to 0045 of the same document). It is said that a woven fabric can be made by weaving this resin-coated flame-retardant fiber yarn as the warp and weft (ibid., paragraph 0046).
　特許文献２には、断熱性を有し遮音性に優れた軽量な断熱遮音材が開示されている。シリカエアロゲル粒子の集合体が陰イオン性官能基を持つ有機ナノファイバーのネットワークにより取り囲まれたセルを基本構成とし、複数のセルが密接した３次元的な連続構造の固体複合体が不織布あるいは連続気泡発泡体の内部に形成されており、軽量で優れた遮音性を有するとされる。 Patent Document 2 discloses a lightweight heat and sound insulation material with excellent heat insulation and sound insulation properties. The basic structure is a cell in which an aggregate of silica aerogel particles is surrounded by a network of organic nanofibers with anionic functional groups, and a solid composite with a three-dimensional continuous structure in which multiple cells are closely spaced is formed inside a nonwoven fabric or open-cell foam, which is said to be lightweight and have excellent sound insulation properties.
　特許文献３には、一次粒子の集合体であるクラスターで骨格が形成された三次元網目構造を有するエアロゲルを原料とし、その一次粒子で骨格が形成された三次元網目構造を有する微粒子を含むことを特徴とするエアロゲル超微粒子が開示されている。この特許文献３は、本願の発明者らによる発明であり、商用的にはＴＩＩＳＡ（株式会社Thermalyticaの登録商標）と呼ばれている。エアロゲル超微粒子は、高性能エアロゲルと同等の熱伝導率を持ち、嵩密度が0.01g/cm3以下であって一般的なエアロゲルの約10分の1以下である。このため軽量で高性能の断熱材料である。エアロゲル超微粒子は、一般的なエアロゲルが二次粒子でその骨格が形成されているのに対して、その二次粒子を構成する一次粒子を中心としてその骨格が形成されているため、極めて微小な粒子であり、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散することを特徴とする。 Patent Document 3 discloses ultrafine aerogel particles, which are made from aerogel having a three-dimensional network structure in which the skeleton is formed by clusters, which are aggregates of primary particles, and which contain fine particles having a three-dimensional network structure in which the skeleton is formed by the primary particles. Patent Document 3 is an invention by the inventors of the present application, and is commercially known as TIISA (a registered trademark of Thermalytica Co., Ltd.). Ultrafine aerogel particles have a thermal conductivity equivalent to that of high-performance aerogel, and a bulk density of 0.01 g/cm 3 or less, which is about one-tenth or less of that of general aerogel. Therefore, they are lightweight and high-performance heat insulating materials. Ultrafine aerogel particles are extremely fine particles because their skeleton is formed mainly by primary particles that constitute the secondary particles, whereas the skeleton of general aerogel is formed by secondary particles, and are characterized in that more than 50% of their volume is dispersed with a particle diameter of 0.1 μm to 1.0 μm as a mode value.
　特許文献４には、繊維強化熱可塑性樹脂シートとシリカ微粒子担持ガラス繊維不織布が開示されている。繊維強化熱可塑性樹脂シートは、熱可塑性のマトリックス樹脂と、ガラス繊維に含有される平均一次粒子径が1～100nmの範囲にあるシリカ微粒子とを含んで構成されている。 Patent Document 4 discloses a fiber-reinforced thermoplastic resin sheet and a glass fiber nonwoven fabric carrying silica microparticles. The fiber-reinforced thermoplastic resin sheet is composed of a thermoplastic matrix resin and silica microparticles contained in the glass fibers and having an average primary particle diameter in the range of 1 to 100 nm.
　特許文献５には、強度が高く断熱性に優れるとされる断熱材が開示されている。断熱材は、エアロゲル粒子と、それを接着する接着剤と、熱融着性接着成分が保護膜によりコーティングされた複合体接着体によって構成されている。 Patent Document 5 discloses a heat insulating material that is said to have high strength and excellent heat insulating properties. The heat insulating material is composed of aerogel particles, an adhesive that bonds them, and a composite adhesive in which a heat-fusible adhesive component is coated with a protective film.
国際公開ＷＯ２０１３／１３６５５２International Publication WO2013/136552 特開２０２２－４１３３２号公報JP 2022-41332 A 国際公開ＷＯ２０２２／１０７３６５International Publication WO2022/107365 特開２０１８－９５６７３号公報JP 2018-95673 A 特開２０１５－１２４７７９号公報JP 2015-124779 A
　本発明の主たる目的は、断熱性能の高い断熱シートを提供することである。本発明の他の目的は、その断熱シートにさらに難燃性能を付加することである。本発明のさらに他の目的は、そのような断熱シートの製造に適した繊維含有懸濁液及び断熱繊維を提供することである。 The primary object of the present invention is to provide an insulating sheet having high insulating performance. Another object of the present invention is to further impart flame retardant performance to the insulating sheet. Yet another object of the present invention is to provide a fiber-containing suspension and insulating fibers suitable for producing such an insulating sheet.
　このような課題を解決するための手段を以下に説明するが、その他の課題と新規な特徴は、本明細書の記述及び添付図面から明らかになるであろう。 　Means for solving these problems are described below, but other problems and novel features will become apparent from the description of this specification and the accompanying drawings.
　本発明によれば、下記の通りである。 According to the present invention, it is as follows:
　すなわち、本発明に係る断熱シートは、母材繊維と断熱性微粒子とを含む断熱シートであって、前記母材繊維は互いに接着され又は織編みされてシート体を形成し、前記断熱性微粒子は、前記母材繊維の内部又は／及び外側に存在している。 In other words, the insulating sheet of the present invention is an insulating sheet containing base fibers and insulating microparticles, the base fibers are bonded to each other or woven to form a sheet body, and the insulating microparticles are present inside and/or outside the base fibers.
　本発明に係る断熱シートの製造方法は、断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程と、結合剤を溶かして結合剤溶液を調製する工程と、前記断熱性微粒子含有懸濁液と、前記結合剤溶液と、母材繊維と、バインダー繊維とを混ぜて繊維含有懸濁液を調製する工程と、前記繊維含有懸濁液から液体成分を除いてシート体を形成する工程（抄紙工程）と、を含む。 The method for manufacturing the insulating sheet according to the present invention includes the steps of dispersing insulating microparticles to prepare an insulating microparticle-containing suspension, dissolving a binder to prepare a binder solution, mixing the insulating microparticle-containing suspension, the binder solution, base fibers, and binder fibers to prepare a fiber-containing suspension, and removing liquid components from the fiber-containing suspension to form a sheet (papermaking process).
　別の本発明に係る断熱シートの製造方法は、熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を得る工程と、前記微粒子含有樹脂を、チャンバー内に配置された細孔を有する容器に収容し、前記容器を加熱しながら回転させて前記細孔から前記微粒子含有樹脂を噴出させて短繊維を得る工程と、前記短繊維をシート状に成形する工程と、を含む。 Another method for manufacturing a heat insulating sheet according to the present invention includes the steps of: mixing a thermoplastic resin with heat insulating particles to obtain a resin containing microparticles; storing the resin containing microparticles in a container having fine holes arranged in a chamber; rotating the container while heating it to eject the resin containing microparticles from the fine holes to obtain short fibers; and forming the short fibers into a sheet.
　さらに別の本発明に係る断熱シートの製造方法は、熱可塑性樹脂を溶融し、該溶融された熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を調製する工程と、前記溶融された前記微粒子含有樹脂を細孔から押し出して繊維を得る工程と、前記繊維を紡糸して糸を得る工程と、前記糸を織編みする工程と、を含む。 A further method for producing a heat insulating sheet according to the present invention includes the steps of melting a thermoplastic resin and mixing the melted thermoplastic resin with heat insulating microparticles to prepare a microparticle-containing resin, extruding the melted microparticle-containing resin through pores to obtain fibers, spinning the fibers to obtain yarn, and weaving and knitting the yarn.
　本発明に係る断熱シートの製造用の繊維含有懸濁液は、断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、母材繊維と、バインダー繊維とが混合されてなる。 The fiber-containing suspension for manufacturing the insulating sheet of the present invention is a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, base fibers, and binder fibers.
　別の本発明に係る断熱シートの製造用の繊維含有懸濁液は、断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、断熱繊維と、バインダー繊維とが混合され、前記断熱繊維は、母材繊維の表面に繊維用の断熱性微粒子が繊維用の結合剤によって接着され、前記繊維用の断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、前記母材繊維はシリカ繊維である。 A fiber-containing suspension for manufacturing a heat insulating sheet according to another aspect of the present invention is a mixture of a heat insulating microparticle-containing suspension in which heat insulating microparticles are dispersed in a solvent, a binder solution, heat insulating fibers, and binder fibers, and the heat insulating fibers are formed by bonding heat insulating microparticles for fibers to the surface of a base fiber with a binder for fibers, and the heat insulating microparticles for fibers are made of aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of their volume being dispersed with a mode of particle diameter of 0.1 μm to 1.0 μm, and the base fiber is silica fiber.
　本発明に係る断熱繊維は、母材繊維の表面に断熱性微粒子が結合剤によって接着され、前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、前記母材繊維はシリカ繊維である。 The insulating fiber of the present invention has insulating fine particles bonded to the surface of a base fiber by a binder, the insulating fine particles are made of aerogel having a three-dimensional mesh structure with a skeleton made of clusters that are aggregates of primary particles, the insulating fine particles have a three-dimensional mesh structure with a skeleton made of the primary particles, and 50% or more of the volume of the insulating fine particles are fine particles dispersed with a mode of particle diameter of 0.1 μm to 1.0 μm, and the base fiber is silica fiber.
　別の本発明に係る断熱繊維は、母材繊維の内部に、断熱性微粒子が少なくとも一部が埋設された状態で存在し、前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、前記母材繊維は熱可塑性樹脂を含む。 Another insulating fiber according to the present invention has insulating microparticles present inside a matrix fiber in a state where they are at least partially embedded, the insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, the insulating microparticles have a three-dimensional mesh structure with a skeleton made up of the primary particles, and 50% or more of the volume of the insulating microparticles are microparticles dispersed with a mode of particle diameters of 0.1 μm to 1.0 μm, and the matrix fiber contains a thermoplastic resin.
　本発明に係る断熱繊維の製造方法は、前記本発明に係る断熱繊維の製造方法であって、前記断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程と、結合剤を溶かして結合剤溶液を調製する工程と、前記断熱性微粒子含有懸濁液と前記結合剤溶液とを混ぜてスラリーを調製する工程と、前記母材繊維に対して、前記スラリーを蒸発源として蒸着する工程とを含む。 The method for producing the insulating fiber according to the present invention is a method for producing the insulating fiber according to the present invention, and includes the steps of dispersing the insulating microparticles to prepare an insulating microparticle-containing suspension, dissolving a binder to prepare a binder solution, mixing the insulating microparticle-containing suspension and the binder solution to prepare a slurry, and depositing the slurry as an evaporation source onto the base fiber.
　別の本発明に係る断熱繊維の製造方法は、前記本発明に係る断熱繊維の製造方法であって、結合剤を溶かして結合剤溶液を調製する工程と、母材繊維に対して、前記結合剤溶液を蒸発源として蒸着する工程と、前記蒸着によって結合剤溶液が表面に付着した前記母材繊維に、断熱性微粒子を機械的に塗す工程と、を含む。 Another method for producing insulating fibers according to the present invention is the same as the method for producing insulating fibers according to the present invention, and includes the steps of dissolving a binder to prepare a binder solution, depositing the binder solution onto base fibers as an evaporation source, and mechanically coating the base fibers with insulating fine particles on the surfaces of which the binder solution has been attached by the deposition.
　なお、「（微粒子を）分散させ」とは、当該微粒子を液体に投入して液中に分散させることを意味し、溶解させることを意味しない。「抄紙工程（シート体形成工程）」は、母材繊維を含む懸濁液を薄く広げ、余分な液体を除去した後に乾燥し、シート体を形成する工程を含む。また、本明細書では、「ポリビニルアルコール」を「ＰＶＡ」（polyvinyl alcohol）と略記し、「ポリビニルアルコール繊維」を「ＰＶＡ繊維」と、「ポリビニルアルコール粉末」を「ＰＶＡ粉末」と略記する場合がある。 Note that "dispersing (the fine particles)" means putting the fine particles into a liquid and dispersing them in the liquid, not dissolving them. The "papermaking process (sheet formation process)" includes the process of thinly spreading a suspension containing base fibers, removing excess liquid, and then drying to form a sheet. In addition, in this specification, "polyvinyl alcohol" may be abbreviated to "PVA" (polyvinyl alcohol), "polyvinyl alcohol fiber" to "PVA fiber," and "polyvinyl alcohol powder" to "PVA powder."
　前記一実施の形態によって得られる効果を簡単に説明すれば下記のとおりである。 The advantages achieved by the above embodiment can be briefly explained as follows:
　すなわち、断熱性能の高い断熱シート、その断熱シートにさらに難燃性能を付加するのに好適な断熱繊維、及びその断熱シートの製造に適した繊維含有懸濁液を提供することができる。 In other words, it is possible to provide a heat insulating sheet with high heat insulating performance, heat insulating fibers suitable for adding flame retardant performance to the heat insulating sheet, and a fiber-containing suspension suitable for manufacturing the heat insulating sheet.
図１は、本発明の一実施形態に係る断熱シートの構成例を示す模式的な説明図である。FIG. 1 is a schematic explanatory diagram showing an example of the configuration of a heat insulating sheet according to one embodiment of the present invention. 図２は、母材繊維とバインダー繊維の長さの関係を示す説明図である。FIG. 2 is an explanatory diagram showing the relationship between the lengths of the base fibers and the binder fibers. 図３は、母材繊維の表面に断熱性微粒子を接着して構成した難燃繊維の構成例を示す説明図である。FIG. 3 is an explanatory diagram showing an example of the configuration of a flame-retardant fiber formed by adhering heat insulating fine particles to the surface of a base fiber. 図４は、本発明の一実施形態に係る断熱シートの製造方法の例を示すフローチャートである。FIG. 4 is a flow chart showing an example of a method for producing a heat insulating sheet according to an embodiment of the present invention. 図５は、本発明の一実施形態に係る難燃繊維の製造方法の例を示すフローチャートである。FIG. 5 is a flow chart illustrating an example of a method for producing a flame-retardant fiber according to one embodiment of the present invention. 図６は、難燃性が付加された断熱シートの製造方法の例を示すフローチャートである。FIG. 6 is a flow chart showing an example of a method for manufacturing a heat insulating sheet having flame retardant properties. 図７は、断熱微粒子の一例であるエアロゲル超微粒子の構造を示す説明図である。FIG. 7 is an explanatory diagram showing the structure of an ultrafine aerogel particle, which is an example of a heat insulating particle. 図８は、断熱微粒子の一例であるエアロゲル超微粒子の粒子径の分布を例示する説明図である。FIG. 8 is an explanatory diagram illustrating the particle size distribution of ultrafine aerogel particles, which are an example of heat insulating particles. 図９は、エアロゲル超微粒子を含む難燃層で被覆されたグラスウールを炎で炙った実験結果を示す実物の写真である。FIG. 9 is a photograph showing the results of an experiment in which glass wool coated with a flame-retardant layer containing ultrafine aerogel particles was heated with a flame. 図１０は、エアロゲル超微粒子を含む難燃層で被覆されたグラスウールを炎で炙った実験結果を示す光学顕微鏡写真である。FIG. 10 is an optical microscope photograph showing the results of an experiment in which glass wool coated with a flame-retardant layer containing ultrafine aerogel particles was heated with a flame. 図１１は、熱可塑性樹脂と断熱性微粒子とが混合されて構成された母材繊維の例を示す説明図である。FIG. 11 is an explanatory diagram showing an example of a base fiber formed by mixing a thermoplastic resin and heat insulating particles. 図１２は、実施形態８に係る断熱シートの製造方法の例を示すフローチャートである。FIG. 12 is a flowchart showing an example of a method for producing a heat insulating sheet according to the eighth embodiment. 図１３は、実施形態８に係る断熱シートの母材繊維を製造する装置の構成例を示す説明図である。FIG. 13 is an explanatory diagram showing an example of the configuration of an apparatus for producing base fibers of the heat insulating sheet according to the eighth embodiment. 図１４は、実施形態９に係る断熱シートの製造方法の例を示すフローチャートである。FIG. 14 is a flowchart showing an example of a method for producing a heat insulating sheet according to the ninth embodiment. 図１５は、公知の紡糸装置の例を示す概略図である。FIG. 15 is a schematic diagram showing an example of a known spinning apparatus. 図１６は、実施例で用いた装置を示す概略図である。FIG. 16 is a schematic diagram showing the apparatus used in the examples. 図１７は、実験結果を示す走査電子顕微鏡（ＳＥＭ）写真である。FIG. 17 is a scanning electron microscope (SEM) photograph showing the experimental results.
１．実施の形態の概要
　先ず、本願において開示される代表的な実施の形態について概要を説明する。代表的な実施の形態についての概要説明で括弧を付して参照する図面中の参照符号はそれが付された構成要素の概念に含まれるものを例示するに過ぎない。 1. Overview of the embodiment First, an overview of the representative embodiment disclosed in the present application will be described. In the overview of the representative embodiment, reference numerals in parentheses in the drawings refer only to components included in the concept of the components to which the reference numerals are attached.
　〔１〕断熱性微粒子が担持された断熱シート（図１，図１１）
　本実施形態で示す断熱シートは、母材繊維（６，３００）と断熱性微粒子（１、１４）とを含む断熱シート（１００）であって、前記母材繊維（６，３００）は互いに接着され又は織編みされてシート体を形成し、前記断熱性微粒子（１、１４）は、前記母材繊維（６，３００）の内部又は／及び外側に存在している断熱シート（１００）である。 [1] Heat insulating sheet carrying heat insulating particles (Fig. 1, Fig. 11)
The insulating sheet shown in this embodiment is an insulating sheet (100) including base fibers (6,300) and insulating microparticles (1, 14), in which the base fibers (6,300) are bonded to each other or woven or knitted to form a sheet body, and the insulating microparticles (1, 14) are present inside and/or outside the base fibers (6,300).
　これにより、断熱性に優れた断熱シートを実現することができる。 This makes it possible to create an insulating sheet with excellent insulating properties.
　〔２〕エアロゲル超微粒子を担持（図７，８）
　〔１〕の断熱シートにおいて、前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子である。 [2] Supporting ultrafine aerogel particles (Figures 7 and 8)
In the heat insulating sheet of [1], the heat insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of the volume being dispersed with a particle diameter of 0.1 μm or more and 1.0 μm or less as a mode.
　これにより、エアロゲル超微粒子の粒子径の小ささを利用して、薄膜化した断熱シートを実現することができる。 This makes it possible to take advantage of the small particle size of ultrafine aerogel particles to create a thin insulating sheet.
　〔３〕バインダー繊維が溶けてできた膜で接着された母材繊維の隙間に断熱性微粒子が担持された断熱シート（図１）
　〔１〕または〔２〕の断熱シートにおいて、前記母材繊維はシリカ繊維であって、母材繊維（６）とバインダー繊維（７）と結合剤（２，但し図1には図示なし）とを含む断熱シート（１００）であって、前記母材繊維は、前記バインダー繊維が溶けてできた膜で互いに接着され、接着された前記母材繊維の隙間に、前記結合剤によって断熱性微粒子（１）が担持される。 [3] A heat insulating sheet in which heat insulating particles are supported in the gaps between the base fibers bonded together by a film formed by dissolving the binder fibers (Figure 1)
In the insulating sheet of [1] or [2], the base fiber is a silica fiber, and the insulating sheet (100) includes a base fiber (6), a binder fiber (7), and a bonding agent (2, not shown in Figure 1), the base fibers are bonded to each other by a film formed by dissolving the binder fiber, and the insulating microparticles (1) are supported in the gaps between the bonded base fibers by the bonding agent.
　これにより、薄膜化した断熱シートを実現することができる。 This makes it possible to create a thin insulating sheet.
　〔４〕難燃性の付加（図３）
　〔３〕の断熱シートにおいて、前記母材繊維の表面には、前記断熱性微粒子が前記結合剤によって接着されている。 [4] Adding flame retardancy (Figure 3)
In the heat insulating sheet of [3], the heat insulating particles are adhered to the surface of the base fiber by the binder.
　これにより、母材繊維の表面に前記断熱性微粒子が存在することで、断熱性に加えて難燃性を付加し、断熱シート全体に難燃性を持たせることができる。ここで、本明細書中で「難燃性が付加される」とは、特定の物に対してなんらかの加工を行うことによって加工前よりもその物が燃焼しにくくなることを指す。 As a result, the presence of the insulating microparticles on the surface of the base fiber imparts flame retardancy in addition to insulating properties, making it possible to impart flame retardancy to the entire insulating sheet. Here, in this specification, "adding flame retardancy" refers to performing some kind of processing on a specific object, making that object less flammable than before the processing.
　〔５〕断熱性微粒子が熱可塑性樹脂に埋設された状態で担持された母材繊維が織編みされて形成された断熱シート（図１１）
　〔１〕または〔２〕の断熱シートにおいて、母材繊維（３００）は、熱可塑性樹脂（８）を含み、断熱性微粒子（１４）は母材繊維（３００）中の前記熱可塑性樹脂（８）に少なくとも一部が埋設された状態で存在し、シート体は、前記母材繊維（３００）が紡糸された糸が織編みされて構成されている。 [5] A heat insulating sheet formed by weaving and knitting a base material fiber carrying heat insulating particles embedded in a thermoplastic resin (FIG. 11)
In the heat insulating sheet of [1] or [2], the base fiber (300) contains a thermoplastic resin (8), the heat insulating microparticles (14) are present in a state in which at least a portion of them is embedded in the thermoplastic resin (8) in the base fiber (300), and the sheet body is formed by weaving and knitting yarns spun from the base fiber (300).
　母材繊維（３００）は、公知の紡糸方法によって紡糸され、該紡糸された糸を公知の方法で織り、又は、編むことで、シート体が形成されている断熱シートである。 The base fiber (300) is spun by a known spinning method, and the spun yarn is woven or knitted by a known method to form a sheet body, which is an insulating sheet.
　これにより、結合剤を使用せずに断熱性能の高い断熱シートを実現することができる。 This makes it possible to create an insulating sheet with high insulating performance without using a binder.
　〔６〕断熱性微粒子が熱可塑性樹脂に埋設された状態の母材繊維が、熱可塑性樹脂が溶けてできた膜で接着されてシート状に形成された断熱シート（図１１）
　〔１〕または〔２〕の断熱シートにおいて、母材繊維（３００）は、熱可塑性樹脂（８）を含み、断熱性微粒子（１４）は母材繊維（３００）中の前記熱可塑性樹脂（８）に少なくとも一部が埋設された状態で存在し、前記シート体は、前記母材繊維が、前記熱可塑性樹脂が溶けてできた膜で互いに接着されることで形成されている。 [6] A heat insulating sheet formed into a sheet by bonding a base fiber in which heat insulating particles are embedded in a thermoplastic resin with a film formed by melting the thermoplastic resin (Figure 11)
In the insulating sheet of [1] or [2], the base fiber (300) contains a thermoplastic resin (8), the insulating particles (14) are present in a state in which at least a portion of them is embedded in the thermoplastic resin (8) in the base fiber (300), and the sheet body is formed by bonding the base fibers to each other with a film formed by melting the thermoplastic resin.
　これにより、結合剤を使用せずに断熱性能の高い断熱シートを実現することができる。 This makes it possible to create an insulating sheet with high insulating performance without using a binder.
　〔７〕断熱シートの製造方法（図４）
　本発明の代表的な実施の形態は、断熱シートの製造方法であって、以下の各工程を含んで構成される。 [7] Manufacturing method of heat insulating sheet (Fig. 4)
A representative embodiment of the present invention is a method for producing a heat insulating sheet, which includes the following steps.
　（Ｓ１）：断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程。
　（Ｓ２）：結合剤を溶かして結合剤溶液を調製する工程。
　（Ｓ３）：前記断熱性微粒子含有懸濁液と、前記結合剤溶液と、母材繊維と、バインダー繊維とを混ぜて繊維含有懸濁液を調製する工程。
　（抄紙工程，Ｓ４）：前記繊維含有懸濁液から液体成分を除いてシート体を形成する工程。 (S1): A step of dispersing heat insulating fine particles to prepare a suspension containing heat insulating fine particles.
(S2): A step of dissolving a binder to prepare a binder solution.
(S3): A step of mixing the heat insulating microparticle-containing suspension, the binder solution, base fibers, and binder fibers to prepare a fiber-containing suspension.
(Paper making process, S4): A process of removing the liquid component from the fiber-containing suspension to form a sheet body.
　これにより、〔１〕～〔６〕に記載される断熱シートの製造方法が提供される。 This provides the manufacturing method for the heat insulating sheet described in [1] to [6].
　〔８〕シリカ繊維の隙間にエアロゲル超微粒子を担持（図１，図４）
　〔７〕の断熱シートの製造方法において、前記母材繊維はシリカ繊維であり、前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子である。 [8] Aerogel ultrafine particles supported in the gaps between silica fibers (Fig. 1, Fig. 4)
In the manufacturing method of the insulating sheet of [7], the base fiber is a silica fiber, and the insulating microparticles are made from an aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, and 50% or more of the volume of the microparticles are dispersed with a particle diameter of 0.1 μm or more and 1.0 μm or less as a mode.
　これにより、上記〔２〕と同様に、エアロゲル超微粒子の粒子径の小ささを利用して、薄膜化した断熱シートの製造方法を提供することができる。 As a result, similar to [2] above, it is possible to provide a method for producing a thin insulating sheet by taking advantage of the small particle size of the ultrafine aerogel particles.
　〔９〕断熱性微粒子が疎水性の場合の製造方法
　〔７〕又は〔８〕に記載される断熱シートの製造方法おいて、前記断熱性微粒子が疎水性であって、前記断熱性微粒子含有懸濁液は、アルコールを含む。 [9] Manufacturing method when the heat insulating fine particles are hydrophobic In the manufacturing method of a heat insulating sheet described in [7] or [8], the heat insulating fine particles are hydrophobic, and the heat insulating fine particle-containing suspension contains alcohol.
　これにより、断熱性微粒子が疎水性であっても、断熱性能の高い断熱シートの製造方法を提供することができる。 This makes it possible to provide a method for manufacturing a heat insulating sheet with high heat insulating performance, even if the heat insulating particles are hydrophobic.
　〔１０〕断熱シートの製造方法
　本発明の別の実施の形態である断熱シートの製造方法は、以下の各工程を含んで構成される。 [10] Method for Producing a Heat Insulation Sheet A method for producing a heat insulation sheet according to another embodiment of the present invention includes the following steps.
　熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を得る工程。 A process in which thermoplastic resin and insulating microparticles are mixed to obtain a microparticle-containing resin.
　前記微粒子含有樹脂を、細孔を有する容器に収容し、前記容器を加熱しながら回転させて前記細孔から前記微粒子含有樹脂を噴出させて短繊維を得る工程。 The process involves placing the microparticle-containing resin in a container with fine holes, and rotating the container while heating it to eject the microparticle-containing resin from the fine holes to obtain short fibers.
　前記短繊維をシート状に成形する工程。 The process of forming the short fibers into a sheet.
　これにより、結合剤を用いずに断熱性微粒子を担持した断熱シートを得ることができる。 This makes it possible to obtain an insulating sheet that supports insulating microparticles without using a binder.
　〔１１〕断熱シートを短繊維から織編みによって構成する断熱シートの製造方法
　〔１０〕の断熱シートの製造方法において、前記短繊維を紡糸して糸を得る工程と、前記糸を織編みする工程と、を含む。 [11] A method for producing an insulating sheet in which the insulating sheet is produced by weaving or knitting staple fibers. The method for producing an insulating sheet in [10] includes a step of spinning the staple fibers to obtain yarn, and a step of weaving or knitting the yarn.
　これにより、織編みされた比較的強度の高いシートからなる断熱性微粒子を担持した断熱シートを得ることができる。
〔１２〕断熱シートを短繊維から成形によって構成する断熱シートの製造方法
　〔１０〕の断熱シートの製造方法における前記短繊維をシート状に成形する工程において、前記短繊維を薄膜状に広げ、加熱することでシート状に成形する。 This makes it possible to obtain a heat insulating sheet made of a woven or knitted sheet having a relatively high strength and carrying heat insulating particles.
[12] A method for manufacturing an insulating sheet by molding short fibers. In the step of molding the short fibers into a sheet in the method for manufacturing an insulating sheet of [10], the short fibers are spread into a thin film and heated to form the sheet.
　これによって、織編み加工することなく簡易に断熱シートを製造することができる。 This makes it possible to easily manufacture insulating sheets without the need for weaving or knitting processes.
　〔１３〕断熱シートを紡績された糸から織編みによって構成する断熱シートの製造方法
　本発明のさらに別の実施の形態である断熱シートの製造方法は、以下の各工程を含んで構成される。 [13] A method for manufacturing a heat insulating sheet by weaving or knitting a heat insulating sheet from spun yarn. A method for manufacturing a heat insulating sheet according to still another embodiment of the present invention includes the following steps.
　熱可塑性樹脂を溶融し、該溶融された熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を調製する工程。
　溶融された前記微粒子含有樹脂を細孔から凝固液中に押し出して繊維を得る工程。
　前記繊維を紡糸して糸を得る工程。
　前記糸を織編みする工程。 A step of melting a thermoplastic resin and mixing the melted thermoplastic resin with heat insulating fine particles to prepare a fine particle-containing resin.
A step of extruding the molten microparticle-containing resin through the pores into a coagulating liquid to obtain fibers.
Spinning the fibers to obtain yarn.
weaving and knitting the yarn.
　これにより織編みされた比較的強度の高いシートからなる断熱性微粒子を担持した断熱シートを得ることができる。 This makes it possible to obtain an insulating sheet made of a woven, knitted, and relatively strong sheet carrying insulating microparticles.
　〔１４〕難燃性が付与された断熱シートの製造方法（図６）
　本発明の代表的な実施の形態は、断熱シートの製造方法であって、以下の各工程を含んで構成される。 [14] Manufacturing method of flame-retardant heat insulating sheet (Fig. 6)
A representative embodiment of the present invention is a method for producing a heat insulating sheet, which includes the following steps.
　断熱性微粒子（１）を分散させて断熱性微粒子含有懸濁液を調製する工程。
　結合剤を溶かして結合剤溶液を調製する工程。
　断熱繊維と、バインダー繊維と、前記断熱性微粒子含有懸濁液と、前記結合剤溶液とを混ぜて繊維含有懸濁液を調製する工程。
　前記繊維含有懸濁液から液体成分を除いてシート体を形成する工程。 A step of dispersing the heat insulating fine particles (1) to prepare a suspension containing heat insulating fine particles.
A process of dissolving a binder to prepare a binder solution.
A step of preparing a fiber-containing suspension by mixing insulating fibers, binder fibers, the insulating microparticle-containing suspension, and the binder solution.
A step of removing liquid components from the fiber-containing suspension to form a sheet body.
　さらに前記断熱繊維は、母材繊維の表面に繊維用の断熱性微粒子が繊維用の結合剤によって接着され、
　前記繊維用の断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり前記母材繊維はシリカ繊維である。 Furthermore, the heat insulating fiber has heat insulating fine particles for fiber bonded to the surface of the base fiber by a binder for fiber,
The insulating microparticles for the fibers are made from aerogel having a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton made up of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 μm or more and 1.0 μm or less as the most frequent value, and the base fiber is silica fiber.
　これにより、母材繊維であるシリカ繊維により高い難燃性をもたせ、難燃性が付与された断熱シートの製造方法を提供することができる。 This makes it possible to provide a method for producing a flame-retardant insulating sheet by imparting high flame retardancy to the silica fiber base fiber.
　〔１５〕超音波蒸着または加熱蒸着（図６）
　〔１４〕に記載される断熱シートの製造方法において、蒸着は、超音波蒸着または加熱蒸着である。 [15] Ultrasonic or thermal evaporation (Fig. 6)
In the method for producing a heat insulating sheet described in [14], the vapor deposition is ultrasonic vapor deposition or thermal vapor deposition.
　これにより、母材繊維であるシリカ繊維の表面に、より効率的に断熱性微粒子（エアロゲル超微粒子)を接着することができる。 This allows the insulating particles (ultrafine aerogel particles) to be more efficiently bonded to the surface of the silica fiber base fiber.
　〔１６〕断熱性微粒子が疎水性の場合の製造方法
　〔１４〕に記載される断熱シートの製造方法おいて、前記断熱性微粒子が疎水性であって、前記第１工程の断熱性微粒子含有懸濁液及び前記繊維用の断熱性微粒子含有懸濁液は、アルコールを含む。 [16] Manufacturing method when the insulating microparticles are hydrophobic In the manufacturing method of an insulating sheet described in [14], the insulating microparticles are hydrophobic, and the insulating microparticle-containing suspension in the first step and the insulating microparticle-containing suspension for the fibers contain alcohol.
　これにより、断熱性微粒子が疎水性であっても、難燃繊維を製造する方法を提供することができる。 This provides a method for producing flame-retardant fibers even when the insulating microparticles are hydrophobic.
　〔１７〕繊維含有懸濁液
　本発明の代表的な実施の形態は、前記断熱シートの製造方法で使用される、断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、母材繊維と、バインダー繊維とが混合された断熱シートの製造用の繊維含有懸濁液である。 [17] Fiber-containing suspension A typical embodiment of the present invention is a fiber-containing suspension for producing an insulating sheet, which is a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, base fibers, and binder fibers, used in the method for producing the insulating sheet.
　〔１８〕難燃性が付加された繊維含有懸濁液
　本発明の代表的な実施の形態は、前記断熱シートの製造方法で使用される、断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、断熱繊維と、バインダー繊維とが混合され、前記断熱繊維は、母材繊維の表面に繊維用の断熱性微粒子が繊維用の結合剤によって接着され、前記繊維用の断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、前記母材繊維はシリカ繊維である、断熱シートの製造用の繊維含有懸濁液である。 [18] Fiber-containing suspension with added flame retardancy A typical embodiment of the present invention is a fiber-containing suspension for producing an insulating sheet, which is used in the method for producing an insulating sheet, and which comprises a mixture of an insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, insulating fibers, and binder fibers, and the insulating fibers are formed by bonding insulating microparticles for the fibers to the surface of a base fiber with a binder for the fibers, the insulating microparticles for the fibers are made from aerogel having a three-dimensional mesh structure with a skeleton composed of clusters that are an aggregate of primary particles, and are microparticles having a three-dimensional mesh structure with a skeleton composed of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 μm or more and 1.0 μm or less as a mode, and the base fiber is silica fiber.
　この繊維含有懸濁液は、抄紙工程（Ｓ４）等の原料として提供することができる。 This fiber-containing suspension can be provided as a raw material for the papermaking process (S4), etc.
　〔１９〕表面にエアロゲル超微粒子が接着された難燃性が付加された断熱繊維（図３）
　本発明の代表的な実施の形態は、繊維に難燃性が付加された断熱繊維（難燃繊維）（２００）であって、以下のように構成される。尚、本明細書中で難燃繊維とは、断熱性と共に難燃性が付加された断熱繊維を指す。 [19] Thermal insulation fiber with flame retardant properties, with ultrafine aerogel particles bonded to the surface (Figure 3)
A representative embodiment of the present invention is a heat insulating fiber (flame retardant fiber) (200) to which flame retardancy has been added, and is configured as follows. In this specification, the flame retardant fiber refers to a heat insulating fiber to which flame retardancy has been added as well as heat insulating properties.
　母材繊維（６）の表面に断熱性微粒子（１）が結合剤（２）によって接着されている。 The insulating particles (1) are bonded to the surface of the base fiber (6) with a binder (2).
　ここで、前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子である。また、前記母材繊維はシリカ繊維である。 The insulating microparticles are made from aerogel, which has a three-dimensional mesh structure with a skeleton made up of clusters that are aggregates of primary particles, and are microparticles with a three-dimensional mesh structure with a skeleton made up of the primary particles, with 50% or more of their volume being dispersed with a particle diameter of 0.1 μm to 1.0 μm as the mode. The matrix fiber is silica fiber.
　これにより、母材繊維であるシリカ繊維に、より高い難燃性をもつ難燃繊維を提供することができる。 This makes it possible to provide a flame-retardant fiber with higher flame retardancy than the silica fiber base fiber.
　〔２０〕表面にエアロゲル超微粒子が接着された断熱繊維（図１１）
　本発明の代表的な実施の形態は、断熱繊維（３００）であって、以下のように構成される。 [20] Thermal insulation fiber with ultrafine aerogel particles bonded to the surface (Figure 11)
An exemplary embodiment of the present invention is an insulating fiber (300) constructed as follows.
　母材繊維（３００）の内部に、断熱性微粒子（１４）が少なくとも一部が埋設された状態で存在し、
　前記断熱性微粒子（１４）は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、
　前記母材繊維（３００）は熱可塑性樹脂（８）を含む。 The heat insulating particles (14) are present in a state where they are at least partially embedded inside the base fiber (300),
The heat insulating fine particles (14) are made from an aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less,
The matrix fiber (300) comprises a thermoplastic resin (8).
　これにより、結合剤を用いることなく母材繊維に断熱性を付加した断熱繊維を提供することができる。 This makes it possible to provide insulating fibers that add insulating properties to the base fiber without using a binder.
　〔２１〕表面にエアロゲル超微粒子が接着された難燃繊維の製造方法（図５(a)）
　〔１９〕に記載される断熱繊維（２００）の製造方法であって、以下の各工程を含んで構成される。 [21] Manufacturing method of flame-retardant fiber with ultrafine aerogel particles bonded to the surface (Fig. 5(a))
A method for producing the insulating fiber (200) described in [19], comprising the following steps:
　（Ｓ１１）：断熱性微粒子（エアロゲル超微粒子）を溶かして断熱性微粒子含有懸濁液を調製する工程。
　（Ｓ１２）：結合剤を溶かして結合剤溶液を調製する工程。
　（Ｓ１３）：前記断熱性微粒子含有懸濁液と前記結合剤溶液とを混ぜてスラリーを調製する工程。
　（Ｓ１４）：前記母材繊維に対して、前記スラリーを蒸発源として蒸着する工程。 (S11): A step of dissolving heat insulating fine particles (ultrafine aerogel particles) to prepare a suspension containing heat insulating fine particles.
(S12): A step of dissolving a binder to prepare a binder solution.
(S13): A step of mixing the heat insulating fine particle-containing suspension and the binder solution to prepare a slurry.
(S14): A step of depositing the slurry as an evaporation source onto the base fiber.
　スラリーに含まれる断熱性微粒子（エアロゲル超微粒子）が母材繊維の表面に蒸着されることにより、その母材繊維により高い難燃性を付加するための製造方法が提供される。 A manufacturing method is provided for imparting high flame retardancy to base fibers by depositing insulating fine particles (ultrafine aerogel particles) contained in the slurry onto the surface of the base fibers.
　〔２２〕表面にエアロゲル超微粒子が接着された難燃繊維の製造方法（図５(b)）
　〔１９〕に記載される断熱繊維（２００）の製造方法であって、以下の各工程を含んで構成される。 [22] Manufacturing method of flame-retardant fiber with ultrafine aerogel particles bonded to the surface (Fig. 5(b))
A method for producing the insulating fiber (200) described in [19], comprising the following steps:
　（Ｓ１５）：結合剤を溶かして結合剤溶液を調製する工程。
　（Ｓ１６）：前記母材繊維に対して、前記結合剤溶液を蒸発源として蒸着する工程。
　（Ｓ１７，粉付け工程）：前記蒸着によって結合剤溶液が表面に付着した前記母材繊維に、断熱性微粒子を機械的に塗す工程。 (S15): A step of dissolving the binder to prepare a binder solution.
(S16): A step of depositing the binder solution onto the base fiber as an evaporation source.
(S17, Powdering step): A step of mechanically coating the heat insulating fine particles onto the base fiber having the binder solution adhered to its surface by the vapor deposition.
　これにより、母材繊維に難燃性を付加するための別の製造方法が提供される。 This provides another manufacturing method for imparting flame retardancy to matrix fibers.
　〔２３〕超音波蒸着または加熱蒸着（図５）
　〔２１〕に記載される断熱繊維の製造方法において、前記第４工程（Ｓ１４）の蒸着は、超音波蒸着または加熱蒸着である。 [23] Ultrasonic or thermal evaporation (Fig. 5)
In the method for producing a thermal insulating fiber described in [21], the deposition in the fourth step (S14) is ultrasonic deposition or thermal deposition.
　これにより、前記母材繊維であるシリカ繊維の表面に、より効率的に断熱性微粒子（エアロゲル超微粒子)を接着することができる。 This allows the insulating particles (ultrafine aerogel particles) to be more efficiently bonded to the surface of the silica fiber, which is the base fiber.
　〔２４〕断熱性微粒子が疎水性の場合の製造方法
　〔１９〕～〔２３〕に記載される難燃繊維の製造方法において、前記断熱性微粒子が疎水性であって、前記断熱性微粒子含有懸濁液は、アルコールを含む。 [24] Manufacturing method when the heat insulating microparticles are hydrophobic In the manufacturing method of the flame-retardant fiber described in [19] to [23], the heat insulating microparticles are hydrophobic, and the heat insulating microparticle-containing suspension contains alcohol.
　これにより、断熱性微粒子が疎水性であっても、難燃繊維を製造する方法を提供することができる。 This provides a method for producing flame-retardant fibers even when the insulating microparticles are hydrophobic.
　２．実施の形態の詳細
　実施の形態について更に詳述する。 2. Details of the embodiment The embodiment will be described in further detail.
　〔実施形態１〕
　図１は、本発明の断熱シートの構成例を示す模式的な説明図である。本発明の断熱シート１００は、母材繊維６とバインダー繊維７と結合剤（２，但し図1には図示なし）とを含み、母材繊維６は、バインダー繊維７が溶けてできた膜（図1には図示なし）で互いに接着され、接着された母材繊維６の隙間に断熱性微粒子１が担持されている。符号３については後述、また実施形態４～５でさらに詳しく説明する。 [Embodiment 1]
Fig. 1 is a schematic explanatory diagram showing an example of the structure of the heat insulating sheet of the present invention. The heat insulating sheet 100 of the present invention contains base material fibers 6, binder fibers 7, and a binder (2, not shown in Fig. 1), the base material fibers 6 are bonded to each other by a film (not shown in Fig. 1) formed by dissolving the binder fibers 7, and heat insulating particles 1 are carried in the gaps between the bonded base material fibers 6. The reference numeral 3 will be described later and in more detail in embodiments 4 and 5.
　これにより、断熱性能の高い断熱シートを提供することができる。母材繊維６よりも非常に短い長さのバインダー繊維７が採用されることによって、一定の厚みの中に母材繊維６の多くの層が形成され、その層を形成する母材繊維６に挟まれた隙間が生まれ、その隙間に多くの断熱性微粒子１を担持することができるため、断熱シート１の断熱性能が向上される。 This makes it possible to provide an insulating sheet with high insulating performance. By using binder fibers 7 that are much shorter than the base fibers 6, many layers of base fibers 6 are formed within a certain thickness, creating gaps between the base fibers 6 that form the layers, and many insulating microparticles 1 can be supported in these gaps, improving the insulating performance of the insulating sheet 1.
　バインダー繊維７としては、例えば、ポリビニルアルコール（ＰＶＡ）繊維、ポリエステル繊維、ポリエステル系複合繊維、アクリル繊維、アクリル系繊維、ナイロン、ポリウレタン繊維、ポリカーボネート繊維などを採用することができる。また、結合剤としては、ポリビニルアルコール（ＰＶＡ）粉末、メチルセルロース、デンプン糊、アラビアゴム糊などを採用することができる。 As the binder fiber 7, for example, polyvinyl alcohol (PVA) fiber, polyester fiber, polyester composite fiber, acrylic fiber, acrylic fiber, nylon, polyurethane fiber, polycarbonate fiber, etc. can be used. In addition, as the binding agent, polyvinyl alcohol (PVA) powder, methyl cellulose, starch paste, gum arabic paste, etc. can be used.
　バインダー繊維７の長さは数10μmが好適である。母材繊維６は例えばシリカ繊維であって、バインダー繊維７よりも著しく長い数10mmである。母材繊維６が平面的（図１では左右方向）に延びるのに対して、バインダー繊維７が母材繊維６を上下（断熱シート１００の厚さ方向）に繋ぐ役割を果たす。母材繊維６とバインダー繊維７が溶けてできた膜（図1には図示なし）で互いに接着され、接着された母材繊維６に隙間が形成され、その中に断熱性微粒子１が担持される。例えば、バインダー繊維７の一例であるＰＶＡ繊維は水で湿った状態では65℃～85℃に加熱されることによって溶けて膜状になる。ここで「溶ける」とは水に溶ける溶解であって熱による融解ではない。シリカ繊維などの母材繊維６は、機械的強度を持つが、繊維に沿って熱が伝導するので断熱性能は期待できない。本発明の断熱シート１００では、母材繊維６が長いためシートの表裏面に平行な方向に延びて、断熱シート１００に面方向の機械的強度を与える。一方、厚さ方向には、図１に例示するように母材繊維６どうしの隙間に、断熱性微粒子１が担持されることによって、断熱シート１００に厚さ方向の断熱性能を与える。 The length of the binder fiber 7 is preferably several tens of micrometers. The matrix fiber 6 is, for example, silica fiber, and is several tens of millimeters longer than the binder fiber 7. While the matrix fiber 6 extends in a plane (horizontal direction in FIG. 1), the binder fiber 7 plays a role in connecting the matrix fiber 6 vertically (thickness direction of the heat insulating sheet 100). The matrix fiber 6 and the binder fiber 7 are bonded to each other by a film (not shown in FIG. 1) formed by melting, and gaps are formed in the bonded matrix fiber 6, in which the heat insulating particles 1 are supported. For example, PVA fiber, which is an example of the binder fiber 7, melts and becomes a film when heated to 65°C to 85°C in a water-wet state. Here, "melt" refers to dissolving in water, not melting due to heat. Matrix fibers 6 such as silica fiber have mechanical strength, but heat is conducted along the fibers, so heat insulating performance cannot be expected. In the heat insulating sheet 100 of the present invention, the base material fibers 6 are long and extend in a direction parallel to the front and back surfaces of the sheet, providing the heat insulating sheet 100 with mechanical strength in the planar direction. On the other hand, in the thickness direction, the heat insulating particles 1 are supported in the gaps between the base material fibers 6 as shown in FIG. 1, thereby providing the heat insulating sheet 100 with heat insulating performance in the thickness direction.
　バインダー繊維７の適切な長さについて説明する。一般に、断熱シートには、面内方向の断熱性能よりも、厚さ方向の断熱性能が求められる。そのため断熱シートの一方の表面から他方の表面に至るバインダー繊維は好ましくない。バインダー繊維の熱伝導率は、母材繊維として多用されるシリカ繊維よりも高いので、バインダー繊維が断熱シートの厚さ方向に一方の表面から他方の表面に至っていると、そのバインダー繊維を通して熱が伝導するので、厚さ方向の断熱性能を下げる方向に作用するからである。製造中に加わる熱で曲がることを考慮しても、バインダー繊維の長さは最大でも、断熱シートの厚さと同等程度である数mmが好ましい。 The appropriate length of the binder fiber 7 will now be explained. In general, insulation sheets are required to have better insulation performance in the thickness direction than in the in-plane direction. For this reason, binder fibers that reach from one surface of the insulation sheet to the other surface are not preferred. The thermal conductivity of binder fibers is higher than that of silica fibers, which are often used as base fibers, so if binder fibers reach from one surface to the other surface of the insulation sheet in the thickness direction, heat will be conducted through the binder fibers, which will act to reduce the insulation performance in the thickness direction. Even taking into account bending due to heat applied during manufacturing, the length of the binder fibers should preferably be at most a few mm, which is approximately the same as the thickness of the insulation sheet.
　一方、バインダー繊維７の適切な長さの最小値は、10μm～数10μmである。図２は、母材繊維６とバインダー繊維７の長さの関係を示す説明図である。母材繊維６どうしが互いに接するように隣接している場合（ａ）には、その隣接する母材繊維６を接着するには、バインダー繊維７には母材繊維６の直径と同程度の長さ以上が求められる。母材繊維６に何らかのコーティングが施され、また本発明のように母材繊維６の隙間に断熱性微粒子などが存在して母材繊維６どうしが離れている場合（ｂ）、（ｃ）、（ｄ）には、求められるバインダー繊維７の長さの最小値は、接続される母材繊維６の距離の１倍から数倍である。即ち、２本を繋ぐ場合（ｂ）母材繊維６間の距離と同程度、３本を直線上に繋ぐ場合（ｃ）母材繊維６間の距離の２倍程度、３本を縫うように繋ぐ場合（ｄ）母材繊維６間の距離の３～４倍程度である。一般に母材繊維として多用されるシリカ繊維の直径は、発明者が実測したところ8μm～12μmであるため、この数倍以内が最小値と位置づけられる。なお、ここで言う最小値とは、それ以下の長さのバインダー繊維が含まれていないことを意味しているのではなく、それ以下の長さのバインダー繊維は、母材繊維を接着する目的に対する寄与が小さいことを意味するに過ぎない。 On the other hand, the appropriate minimum length of the binder fiber 7 is 10 μm to several tens of μm. Figure 2 is an explanatory diagram showing the relationship between the lengths of the base material fibers 6 and the binder fibers 7. When the base material fibers 6 are adjacent to each other so as to be in contact with each other (a), the binder fibers 7 are required to have a length equal to or greater than the diameter of the base material fibers 6 in order to bond the adjacent base material fibers 6. When the base material fibers 6 are coated with some kind of material, or when the base material fibers 6 are separated from each other due to the presence of insulating fine particles or the like in the present invention (b), (c), or (d), the minimum length of the binder fibers 7 required is one to several times the distance between the base material fibers 6 to be connected. That is, when two fibers are connected (b), it is about the same as the distance between the base material fibers 6, when three fibers are connected in a straight line (c), it is about twice the distance between the base material fibers 6, and when three fibers are connected in a stitching manner (d), it is about three to four times the distance between the base material fibers 6. The diameter of silica fibers, which are generally used as base fibers, is 8 μm to 12 μm according to measurements by the inventors, so the minimum value is set to be within several times this value. Note that the minimum value mentioned here does not mean that there are no binder fibers shorter than this length, but simply means that binder fibers shorter than this length have a small contribution to the purpose of bonding the base fibers.
　以上のように、母材繊維６とバインダー繊維７の長さを適切に設計することにより、強度と断熱性能を調整することができる。 As described above, the strength and heat insulating performance can be adjusted by appropriately designing the length of the base fiber 6 and the binder fiber 7.
　断熱性微粒子１として、特許文献３に記載されるエアロゲル超微粒子を採用するのが好適である。 As the insulating fine particles 1, it is preferable to use the ultrafine aerogel particles described in Patent Document 3.
　図７は、一般的なエアロゲル微粉末と一次粒子によって骨格が形成されたエアロゲル超微粒子の構造を比較して示す説明図である。一般的なエアロゲル微粉末１３の三次元網目構造は、一次粒子１１のクラスターである二次粒子１２を単位として構成されている（図７(a)）のに対して、このエアロゲル超微粒子１４は、その一次粒子１１を骨格とし形成された三次元網目構造となっている（図７(b)）。 Figure 7 is an explanatory diagram showing a comparison of the structures of general aerogel fine powder and ultrafine aerogel particles whose skeleton is formed by primary particles. The three-dimensional mesh structure of general aerogel fine powder 13 is composed of units of secondary particles 12, which are clusters of primary particles 11 (Figure 7(a)), whereas ultrafine aerogel particles 14 have a three-dimensional mesh structure formed with the primary particles 11 as the skeleton (Figure 7(b)).
　一般に流通しているエアロゲルは顆粒であって、二次粒子１２を単位として骨格を構成された三次元網目構造になっているので、これを、粉砕装置を使って細かく粉砕しても、骨格の構造は変わらない。以下に実験結果を示す。図８は、下段から順に、エアロゲル顆粒、エアロゲル粉末、エアロゲル微粉末、及び、一次粒子によって骨格が形成された微粒子であるエアロゲル超微粒子について、それぞれの粒子径の頻度分布の一例を示す説明図である。エアロゲル顆粒は、一般に流通しているエアロゲル顆粒そのものである。エアロゲル粉末は、三井電気精機株式会社製のスピンミックスホモジナイザーSX08を用いて、エアロゲル顆粒を5000～7000rpmで２分間粉砕して製作したエアロゲル粉末である。エアロゲル微粉末は、Blendtec社製のSTEALTH885を用いて、エアロゲル顆粒を21000rpmで20秒間粉砕することによって、さらに粒子径を小さくすることを試みた微粉末である。図８の横軸は粒子径、縦軸は相対粒子量の頻度分布である。右側の縦軸に頻度、左側の縦軸に積算値が示されている。図８は、レーザー回折式粒子径分布（PSD: particle size distribution）測定装置による観測結果である。本明細書において、粒子径についてはPSD測定を前提として説明する。ただし、PSD測定では、粒子自体の径だけではなく、粒子の凝集も粒子径として観測されるため、真の粒子径は測定値よりも小さい可能性が高い。測定法に依存した粒子径の相違があれば、換算して理解いただきたい。より具体的には、図８は、株式会社島津製作所製レーザー回折式粒子径分布測定装置SALD-2300を用いて測定した粒度分布である。粒度分布とは、測定対象となるサンプル粒子群の中に、どのような大きさ（粒子径）の粒子が、どのような割合（全体を100％とする相対粒子量）で含まれているかを示す指標で、粒子量の次元（オーダー）は体積基準である。 Aerogels that are generally available are granules that have a three-dimensional mesh structure with a skeleton consisting of secondary particles 12 as units, so even if they are finely crushed using a crushing device, the skeleton structure does not change. The experimental results are shown below. Figure 8 is an explanatory diagram showing an example of the frequency distribution of particle sizes for aerogel granules, aerogel powder, aerogel fine powder, and aerogel ultrafine particles, which are fine particles with a skeleton formed by primary particles, in order from the bottom. The aerogel granules are the aerogel granules that are generally available. The aerogel powder is an aerogel powder produced by crushing aerogel granules at 5000 to 7000 rpm for 2 minutes using a Spin Mix Homogenizer SX08 manufactured by Mitsui Electric Seiki Co., Ltd. The aerogel fine powder is a fine powder produced by crushing aerogel granules at 21000 rpm for 20 seconds using a STEALTH885 manufactured by Blendtec Co., Ltd., in an attempt to further reduce the particle size. The horizontal axis of Figure 8 is the particle size, and the vertical axis is the frequency distribution of the relative particle amount. The right vertical axis shows the frequency, and the left vertical axis shows the cumulative value. Figure 8 shows the results of observations made using a laser diffraction particle size distribution (PSD) measurement device. In this specification, particle size is explained on the assumption that PSD measurement is used. However, in PSD measurement, not only the diameter of the particle itself but also the aggregate of particles is observed as the particle diameter, so the true particle diameter is likely to be smaller than the measured value. If there is a difference in particle diameter depending on the measurement method, please convert it to understand. More specifically, Figure 8 shows the particle size distribution measured using a laser diffraction particle size distribution measurement device SALD-2300 manufactured by Shimadzu Corporation. Particle size distribution is an index that shows what size (particle diameter) of particles is contained in the sample particle group to be measured and what the ratio (relative particle amount with the total being 100%) is, and the dimension (order) of the particle amount is based on volume.
　一般に流通しているエアロゲル顆粒は、約400μmの粒子径を平均値として相対粒子量は1つのピークのみをもつ（図８最下段）。このエアロゲル顆粒を、上述のような装置を用いて粉砕したとき、エアロゲル粉末は平均約90μm、エアロゲル微粉末は平均約50μmの粒子径となるが、それぞれ相対粒子量のピークは1つである（3段目と2段目）。これに対して、エアロゲル超微粒子は、平均粒子径約20μmの第１のピークと平均粒子径約0.3μmの第２のピークをもち、相対粒子量は、平均粒子径約20μmの第1ピークが21.2%、平均粒子径約0.3μmの第2ピークが78.8%である。これは、平均粒子径約20μmの第1ピークが二次粒子１２を単位として骨格を構成された三次元網目構造を持つ微粒子で構成されているのに対して、平均粒子径約0.3μmの第2ピークは一次粒子で骨格が形成された三次元網目構造を有する微粒子で構成されているからである。 　Generally available aerogel granules have only one peak in relative particle amount with an average particle size of about 400 μm (bottom row of Figure 8). When these aerogel granules are crushed using the device described above, the aerogel powder has an average particle size of about 90 μm, and the aerogel fine powder has an average particle size of about 50 μm, but each has one peak in relative particle amount (third and second rows). In contrast, ultrafine aerogel particles have a first peak with an average particle size of about 20 μm and a second peak with an average particle size of about 0.3 μm, and the relative particle amount of the first peak with an average particle size of about 20 μm is 21.2%, and the second peak with an average particle size of about 0.3 μm is 78.8%. This is because the first peak, with an average particle size of approximately 20 μm, is composed of fine particles with a three-dimensional mesh structure whose skeleton is made up of secondary particles 12, whereas the second peak, with an average particle size of approximately 0.3 μm, is composed of fine particles with a three-dimensional mesh structure whose skeleton is made up of primary particles.
　一般のエアロゲルは、その三次元網目構造の骨格が二次粒子であるために、粉砕条件をどこまで高めても、粒子径10μm以下の微粒子を製作するのは困難である。一次粒子で骨格が形成された三次元網目構造を有する微粒子を製作するには、通常のエアロゲル製造工程とは異なり、粉砕条件だけでなくエージング条件を大幅に変更する等、製造方法の根本的な変更が必要である。 General aerogel has a three-dimensional mesh structure whose skeleton is made up of secondary particles, so no matter how high the grinding conditions are, it is difficult to produce fine particles with a particle size of 10 μm or less. In order to produce fine particles with a three-dimensional mesh structure whose skeleton is made up of primary particles, it is necessary to fundamentally change the manufacturing method, such as significantly changing not only the grinding conditions but also the aging conditions, unlike the normal aerogel manufacturing process.
　本発明の断熱シート１００において、断熱性微粒子１は以上説明したエアロゲル超微粒子、即ち、一次粒子１１の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する断熱性微粒子が好適である。また母材繊維６としてはシリカ繊維、バインダー繊維としてはＰＶＡ繊維、結合剤としてはＰＶＡが好適である。上述したように、代表的な母材繊維６であるシリカ繊維は太さが約10μmなので、数100μmエアロゲル顆粒を母材繊維の隙間に担持することができるようなサイズ関係にはなく、隙間に担持する構造をとるには、1μm以下のエアロゲル超微粒子が好適である。 In the heat insulating sheet 100 of the present invention, the heat insulating fine particles 1 are preferably the aerogel ultrafine particles described above, that is, heat insulating fine particles made of aerogel having a three-dimensional mesh structure with a skeleton formed of clusters that are aggregates of primary particles 11, having a three-dimensional mesh structure with a skeleton formed of the primary particles, and having a mode of particle diameters of 0.1 μm to 1.0 μm for 50% or more of the volume. In addition, silica fiber is preferable as the base fiber 6, PVA fiber is preferable as the binder fiber, and PVA is preferable as the bonding agent. As described above, silica fiber, which is a typical base fiber 6, has a thickness of about 10 μm, so it is not a size relationship that allows aerogel granules of several hundred μm to be supported in the gaps of the base fiber, and aerogel ultrafine particles of 1 μm or less are preferable to form a structure that supports them in the gaps.
　これにより、エアロゲル超微粒子の粒子径が極めて小さいという特徴を活かした薄い断熱シートを提供することができる。本実施形態の断熱シート１００において、その厚さを3mm以下に薄くした場合でも、断熱性微粒子１としてエアロゲル超微粒子を採用することにより、熱伝導率を約40mW/mKから30mW/mK未満に改善することができる。粒子径が大きな断熱性粒子では、薄膜化した場合に厚さ方向に並ぶ粒子の数が少なく、粒子の殻による熱伝導の寄与が大きいのに対して、エアロゲル超微粒子はその粒子径が極めて小さいので薄膜化した場合に厚さ方向には粒子よりもその隙間（空隙）が大きくなって、粒子の殻による熱伝導が小さく、さらに空隙が空気の対流を妨げるため、断熱性能が向上する。 This makes it possible to provide a thin insulating sheet that takes advantage of the extremely small particle diameter of the ultrafine aerogel particles. Even when the thickness of the insulating sheet 100 of this embodiment is reduced to 3 mm or less, the thermal conductivity can be improved from approximately 40 mW/mK to less than 30 mW/mK by using ultrafine aerogel particles as the insulating particles 1. With insulating particles with a large particle diameter, the number of particles aligned in the thickness direction is small when the sheet is made thin, and the contribution of the shells of the particles to heat conduction is large, whereas ultrafine aerogel particles have an extremely small particle diameter, so when the sheet is made thin, the gaps (voids) are larger than the particles in the thickness direction, and the heat conduction by the shells of the particles is small. Furthermore, the voids impede air convection, improving the insulating performance.
　〔難燃性の付加〕
　断熱シート１００において、母材繊維６の表面には、結合剤２によって断熱性微粒子１を接着するとよい。これにより、母材繊維６に断熱性と共に難燃性を付加し、断熱シート１００全体に難燃性を持たせることができる。 [Adding flame retardancy]
In the heat insulating sheet 100, it is preferable to adhere heat insulating particles 1 to the surface of the base fiber 6 with a binder 2. This imparts flame retardancy as well as heat insulating properties to the base fiber 6, and makes the entire heat insulating sheet 100 flame retardant.
　図３は、母材繊維６の表面に断熱性微粒子１を接着して構成した難燃繊維２００（難燃性が付加された断熱繊維）の構成例を示す説明図である。母材繊維６の表面をすべて覆うように、断熱性微粒子１を含む難燃層３を形成する方が確実であるが、図３に示すように島状に難燃層３を形成しても難燃性を高める効果が認められた。例えば、断熱性微粒子１としてエアロゲル超微粒子を採用すると、断熱シート１００の表面を1000℃を超える高温の炎で炙っても焦げない程度の難燃性を付加することができた。詳しくは、実施形態３～５及び実施例で説明する。 Figure 3 is an explanatory diagram showing an example of the configuration of a flame-retardant fiber 200 (insulating fiber with added flame retardancy) formed by adhering insulating fine particles 1 to the surface of a base fiber 6. It is more reliable to form a flame-retardant layer 3 containing insulating fine particles 1 so as to cover the entire surface of the base fiber 6, but it has been found that the effect of increasing flame retardancy can be achieved even when the flame-retardant layer 3 is formed in islands as shown in Figure 3. For example, when ultrafine aerogel particles are used as the insulating fine particles 1, it is possible to add flame retardancy to the extent that the surface of the insulating sheet 100 will not burn even if it is heated with a high-temperature flame exceeding 1000°C. Details will be explained in embodiments 3 to 5 and the examples.
　〔実施形態２〕
　実施形態１の断熱シート１００の製造方法について説明する。 [Embodiment 2]
A method for producing the heat insulating sheet 100 of the first embodiment will be described.
　図４は、本発明の一実施形態に係る断熱シートの製造方法の例を示すフローチャートである。断熱シート１００の製造方法は、以下の各工程を含んで構成される。 FIG. 4 is a flow chart showing an example of a method for manufacturing a heat insulating sheet according to one embodiment of the present invention. The method for manufacturing the heat insulating sheet 100 includes the following steps:
　第１工程（Ｓ１）：断熱性微粒子１を分散させて断熱性微粒子含有懸濁液を調製する。ここで「（微粒子を）分散させ」とは、当該微粒子を液体（媒質）に投入して撹拌して分散させることを意味しており、溶解することは意味していない。断熱性微粒子1が疎水性の場合にはアルコールに、親水性の場合には水に分散させる。断熱性微粒子1が、その表面がトリメチルシロキシ基または他の疎水基で修飾されているエアロゲル超微粒子であるときは強い疎水性を示し、アルコール（例えば、エタノール）とは親和性が高いため、第1工程（Ｓ１）ではアルコールを媒質とするとよい。一方、疎水性のエアロゲル超微粒子を450℃程度の高温で処理すると表面のトリメチルシロキシ基が消失してシリカが露出し、親水性になるので、断熱性微粒子含有懸濁液は水を媒質とする液とすればよく、アルコール（例えば、エタノール）を不要とすることができる。シリカエアロゲルの疎水性官能基は、一般に390℃が熱分解の開始温度として知られているが、断熱性があるため試料の中心部も十分に加熱するためには余裕をもって450℃程度の高温が好ましい。
　第２工程（Ｓ２）：結合剤を溶かして結合剤溶液を調製する。結合剤としては例えばＰＶＡ粉末が好適であり、ＰＶＡ粉末を常温の水に投入した後に約80℃に加熱して撹拌して溶かし、その後常温に戻す。
　第３工程（Ｓ３）：第１工程（Ｓ１）で調製した断熱性微粒子含有懸濁液と、第２工程（Ｓ２）で調製した結合剤溶液と、母材繊維６と、バインダー繊維７とを混ぜて繊維含有懸濁液を調製する。
　第４工程（Ｓ４）：第３工程（Ｓ３）で調製した繊維含有懸濁液を抄く、抄紙工程である。 First step (S1): Disperse the heat insulating fine particles 1 to prepare a suspension containing heat insulating fine particles. Here, "disperse (fine particles)" means to put the fine particles in a liquid (medium) and disperse them by stirring, not to dissolve them. If the heat insulating fine particles 1 are hydrophobic, they are dispersed in alcohol, and if they are hydrophilic, they are dispersed in water. When the heat insulating fine particles 1 are ultrafine aerogel particles whose surfaces are modified with trimethylsiloxy groups or other hydrophobic groups, they show strong hydrophobicity and have high affinity with alcohol (e.g., ethanol), so alcohol is preferably used as the medium in the first step (S1). On the other hand, when hydrophobic ultrafine aerogel particles are treated at a high temperature of about 450°C, the trimethylsiloxy groups on the surface disappear, exposing the silica, and the particles become hydrophilic, so that the heat insulating fine particle-containing suspension can be prepared as a liquid containing water as the medium, and alcohol (e.g., ethanol) is not required. The hydrophobic functional group of silica aerogel is generally known to begin to decompose at 390°C. However, due to its insulating properties, a higher temperature of around 450°C is preferable in order to sufficiently heat the center of the sample.
Second step (S2): Dissolve the binder to prepare a binder solution. For example, PVA powder is suitable as the binder. The PVA powder is put into water at room temperature, heated to about 80°C, stirred to dissolve, and then returned to room temperature.
Third step (S3): The insulating microparticle-containing suspension prepared in the first step (S1), the binder solution prepared in the second step (S2), base material fibers 6, and binder fibers 7 are mixed together to prepare a fiber-containing suspension.
Fourth step (S4): This is a papermaking step in which the fiber-containing suspension prepared in the third step (S3) is paper-made.
　第４工程（Ｓ４）の「抄く」とは、紙すき（和紙の製造方法の工程）と同様の工程であって、懸濁液から液体成分を除去し、懸濁液中の固体成分を薄膜状に残してシート体を形成する工程である。より具体的には、液体を通す網を張った状態で第３工程（Ｓ３）の繊維含有懸濁液を通すことによって、液体（媒質）は通過し、母材繊維６とバインダー繊維７が網の上に残る。残った母材繊維６とバインダー繊維７は互いに絡まり合い、断熱性微粒子１と結合剤を含んだ液で濡れた状態である。母材繊維６はバインダー繊維７よりも長いので網に沿って広がり、バインダー繊維７は短いため母材繊維６の間に挟まる。母材繊維６とバインダー繊維７が絡まった状態で網の上に広がり、その隙間に断熱性微粒子１と結合剤溶液が保持されている。網から剥がすとシート状になる。１枚のまままたは何枚か重ねて上下方向に押しつぶして余分な液体を絞りとり、乾燥させると不織布、即ち本実施形態１の断熱シート１００となる。乾燥のために加熱されることにより、バインダー繊維７の表面が一部または全部溶けて膜状になり、接している母材繊維６と接着される。バインダー繊維７をＰＶＡ繊維とした場合、65℃～85℃で乾燥するとよい。 The "sheeting" in the fourth step (S4) is a process similar to papermaking (a process in the manufacturing method of Japanese paper), in which liquid components are removed from the suspension and the solid components in the suspension are left in a thin film to form a sheet. More specifically, by passing the fiber-containing suspension in the third step (S3) through a liquid-permeable mesh, the liquid (medium) passes through and the matrix fibers 6 and binder fibers 7 remain on the mesh. The remaining matrix fibers 6 and binder fibers 7 are entangled with each other and are wet with a liquid containing heat insulating fine particles 1 and a binder. The matrix fibers 6 are longer than the binder fibers 7 and spread along the mesh, while the binder fibers 7 are shorter and are sandwiched between the matrix fibers 6. The matrix fibers 6 and binder fibers 7 are entangled and spread over the mesh, and the heat insulating fine particles 1 and binder solution are held in the gaps. When peeled off from the mesh, it becomes a sheet. The sheet is pressed vertically as is or multiple sheets are stacked together to squeeze out excess liquid, and then dried to produce a nonwoven fabric, i.e., the heat insulating sheet 100 of this embodiment 1. When heated for drying, the surfaces of the binder fibers 7 melt in part or in whole, forming a film that bonds with the adjacent base fibers 6. When the binder fibers 7 are PVA fibers, it is recommended to dry them at 65°C to 85°C.
　第４工程（Ｓ４）で調製される繊維含有懸濁液は、第２工程（Ｓ２）の結合剤溶液を含んでいるので、乾燥した後も結合剤が機能して、断熱性微粒子１が母材繊維６の隙間からこぼれ落ちないように担持される。 The fiber-containing suspension prepared in the fourth step (S4) contains the binder solution from the second step (S2), so the binder continues to function even after drying, supporting the insulating microparticles 1 so that they do not fall out of the gaps between the base fibers 6.
　これにより、実施形態１の断熱シート１００の製造方法が提供される。 This provides a method for manufacturing the insulating sheet 100 of embodiment 1.
　第１工程（Ｓ１）における断熱性微粒子1の濃度は例えば、0.1～0.5wt%、第２工程（Ｓ２）におけるポリビニルアルコールの濃度は例えば0.075g/dl、繊維含有懸濁液における母材繊維６とバインダー繊維７の含有量は例えばそれぞれ0.5wt%、0.025wt%とされる。 The concentration of the insulating microparticles 1 in the first step (S1) is, for example, 0.1 to 0.5 wt%, the concentration of the polyvinyl alcohol in the second step (S2) is, for example, 0.075 g/dl, and the contents of the base fibers 6 and binder fibers 7 in the fiber-containing suspension are, for example, 0.5 wt% and 0.025 wt%, respectively.
　断熱性微粒子含有懸濁液における断熱性微粒子1の含有量は、液中に均一に分散する範囲でできるだけ多くするとよい。断熱性微粒子1の含有量は凝集しない程度を上限とし、これに適した媒質の量を添加する。添加する媒質の量が少なすぎると、懸濁液中の断熱性微粒子1が凝集しクラスターになり、均一に分散しない。一方、媒質の量を多くしすぎると単位体積当たりの断熱性微粒子1の含有量が低下するので、トレードオフの関係にある。実験等によって最適化設計する。 The content of insulating microparticles 1 in the suspension containing insulating microparticles should be as high as possible while still allowing uniform dispersion in the liquid. The content of insulating microparticles 1 should be limited to the amount at which they do not aggregate, and an appropriate amount of medium should be added. If the amount of medium added is too small, the insulating microparticles 1 in the suspension will aggregate and form clusters, and will not disperse uniformly. On the other hand, if the amount of medium is too large, the content of insulating microparticles 1 per unit volume will decrease, so there is a trade-off. Optimize the design through experiments, etc.
　繊維含有懸濁液については、母材繊維６の含有量を増やすことにより、シートの強度、例えば引っ張り強度を増すことができる。また、バインダー繊維７の含有量を増やすことにより、シートをさらに強化することができる反面、断熱性能は犠牲になる。 For fiber-containing suspensions, the strength of the sheet, for example the tensile strength, can be increased by increasing the content of matrix fibers 6. Also, the sheet can be further strengthened by increasing the content of binder fibers 7, but this comes at the expense of thermal insulation performance.
　〔実施形態３〕
　本発明の一実施形態に係る難燃繊維について説明する。この難燃繊維は、実施形態１で図３を引用して説明したように、母材繊維６の表面に結合剤によって断熱性微粒子１を接着して製作することができる。実施形態１及び２でこの難燃繊維を母材繊維として用いれば、断熱シート１００に難燃性を付加することができる。このときの断熱性微粒子１としては、エアロゲル超微粒子が特に好適である。 [Embodiment 3]
A flame-retardant fiber according to one embodiment of the present invention will be described. As explained in embodiment 1 with reference to Fig. 3, this flame-retardant fiber can be produced by bonding heat insulating fine particles 1 to the surface of the base fiber 6 with a binder. If this flame-retardant fiber is used as the base fiber in embodiments 1 and 2, flame retardancy can be imparted to the heat insulating sheet 100. In this case, ultrafine aerogel particles are particularly suitable as the heat insulating fine particles 1.
　エアロゲル超微粒子は原料として、二酸化珪素の純度が高いシリカエアロゲルを用いると、シリカの難燃性をそのまま有する断熱性微粒子となる。母材繊維６として一般的なシリカ繊維を例にとると、その直径は約8μm～12μmであるのに対し、図８を引用して説明したとおり、従来のエアロゲル微粉末の粒子径は数10μm～数100μmであるので、シリカ繊維の表面に付着するというような態様で接着することはできない。一方、エアロゲル超微粒子の直粒子径は大半が0.3μm～0.7μmに分布するので、シリカ繊維の表面に付着させることができる。実施形態１の「難燃性の付加」で説明したように、母材繊維６の表面をすべて覆うように、断熱性微粒子１を含む難燃層３を形成する方が確実であるが、図３に示すように島状に難燃層３を形成しても難燃性を高めることができる。断熱性微粒子１としては、上述のようにエアロゲル超微粒子が好適である。ただし、これに限定されない。難燃性を備えて母材繊維の直径よりも十分に小さい粒子径をもつような微粒子であればよい。 When silica aerogel, which is a high-purity silicon dioxide, is used as the raw material for the aerogel ultrafine particles, the particles retain the flame retardancy of silica. Taking typical silica fibers as an example of the matrix fiber 6, the diameter is about 8 μm to 12 μm, whereas the particle diameter of conventional aerogel fine powder is several tens of μm to several hundreds of μm as explained with reference to FIG. 8, so that it cannot be bonded in such a manner that it adheres to the surface of the silica fiber. On the other hand, the linear particle diameter of the aerogel ultrafine particles is mostly distributed in the range of 0.3 μm to 0.7 μm, so that it can be adhered to the surface of the silica fiber. As explained in "Adding flame retardancy" of the first embodiment, it is more reliable to form the flame retardant layer 3 containing the insulating fine particles 1 so as to cover the entire surface of the matrix fiber 6, but the flame retardancy can also be increased by forming the flame retardant layer 3 in an island shape as shown in FIG. 3. As described above, the insulating fine particles 1 are preferably aerogel ultrafine particles. However, this is not limited to this. Any fine particles that are flame retardant and have a particle size that is sufficiently smaller than the diameter of the base fiber will suffice.
　〔実施形態４〕
　実施形態３の難燃繊維の製造方法について説明する。図５は、本発明の一実施形態に係る難燃繊維の製造方法の例を示すフローチャートである。母材繊維６の表面に断熱性微粒子１を蒸着する製造方法（ａ）と、母材繊維６の表面に断熱性微粒子１を粉付けする製造方法（ｂ）とを示す。 [Embodiment 4]
A method for producing a flame-retardant fiber according to embodiment 3 will now be described. Fig. 5 is a flow chart showing an example of a method for producing a flame-retardant fiber according to one embodiment of the present invention. A method for producing a flame-retardant fiber according to embodiment 3 will be described ...
　（ａ）母材繊維６の表面に断熱性微粒子１を蒸着する難燃繊維の製造方法は、以下の各工程を含んで構成される。 (a) The method for producing a flame-retardant fiber by vapor-depositing insulating microparticles 1 onto the surface of a base fiber 6 includes the following steps:
　第１工程（Ｓ１１）：断熱性微粒子１を分散させて断熱性微粒子含有懸濁液を調製する。Ｓ１と同様に、断熱性微粒子1が親水性の場合には水を媒質として、疎水性の場合にはアルコールを媒質として分散させる。
　第２工程（Ｓ１２）：結合剤を溶かして結合剤溶液を調製する。Ｓ２と同様に、結合剤としては例えばＰＶＡ粉末が好適であり、ＰＶＡ粉末を常温の水に投入した後に約80℃に加熱して撹拌して溶かし、その後常温に戻す。
　第３工程（Ｓ１３）：第１工程（Ｓ１１）で調製した断熱性微粒子含有懸濁液と、第２工程（Ｓ１２）で調製した結合剤溶液とを混ぜてスラリーを調製する。
　第４工程（Ｓ１４）：母材繊維６に対して、第３工程（Ｓ１３）で調製したスラリーを蒸発源として蒸着する。母材繊維６は、シート状、ブランケット状、パット状または綿状など、任意の形態でよいし、解繊された状態でもよい。 First step (S11): Prepare a suspension containing heat insulating particles by dispersing heat insulating particles 1. As in S1, if the heat insulating particles 1 are hydrophilic, they are dispersed in water as a medium, and if they are hydrophobic, they are dispersed in alcohol as a medium.
Second step (S12): Dissolve the binder to prepare a binder solution. As in S2, the binder is preferably, for example, PVA powder, which is added to water at room temperature, heated to about 80°C, stirred to dissolve, and then returned to room temperature.
Third step (S13): The heat insulating fine particle-containing suspension prepared in the first step (S11) and the binder solution prepared in the second step (S12) are mixed to prepare a slurry.
Fourth step (S14): The slurry prepared in the third step (S13) is evaporated as an evaporation source onto the base fiber 6. The base fiber 6 may be in any form such as a sheet, blanket, pad, or cotton, or may be in a defibrated state.
　これにより、母材繊維に、より高い難燃性を付加するための製造方法を提供することができる。第４工程（Ｓ１４）の蒸着は、超音波蒸着または加熱蒸着とすると好適である。これにより、母材繊維６の表面に、より効率的に断熱性微粒子１を接着することができる。ここで「より効率的に」とは、少ない消費量で多くの断熱性微粒子１を接着させることができることを意味している。第４工程（Ｓ１４）において蒸着に代えて、第３工程（Ｓ１３）で調製されるスラリーを噴霧、または、シート状またはブランケット状の母材繊維６を浸した後に引き上げて乾燥する工程を採用することもできる。 This provides a manufacturing method for imparting higher flame retardancy to the base fiber. The deposition in the fourth step (S14) is preferably ultrasonic deposition or heat deposition. This allows the insulating fine particles 1 to be adhered to the surface of the base fiber 6 more efficiently. Here, "more efficiently" means that a large amount of insulating fine particles 1 can be adhered with a small amount of consumption. Instead of deposition in the fourth step (S14), a step of spraying the slurry prepared in the third step (S13) or immersing the sheet-like or blanket-like base fiber 6 and then pulling it up and drying it can also be adopted.
　断熱性微粒子（エアロゲル超微粒子)は、その表面がトリメチルシロキシ基または他の疎水基で修飾されているときは強い疎水性を示す一方、アルコール（例えば、エタノール）とは親和性が高いため、第1工程（Ｓ１）ではエタノールを媒質とした。微粒子としては、エアロゲル超微粒子以外でも耐熱性と疎水性を発現させる物質材料であれば任意であり、一般に疎水性微粒子はアルコールとの親和性が高く、均一に分散させることができるので、他の耐熱性疎水性微粒子とそれに適する媒質に代替しても良い。一方、断熱性微粒子（エアロゲル超微粒子）が親水性の場合にはアルコール（エタノール）を使う必要がなく、第1工程（Ｓ１）では水を媒質とすれば良い。 The insulating fine particles (ultrafine aerogel particles) exhibit strong hydrophobicity when their surfaces are modified with trimethylsiloxy groups or other hydrophobic groups, but have a high affinity for alcohol (e.g., ethanol), so ethanol was used as the medium in the first step (S1). The fine particles can be any material other than ultrafine aerogel particles that exhibits heat resistance and hydrophobicity, and since hydrophobic fine particles generally have a high affinity for alcohol and can be uniformly dispersed, other heat-resistant hydrophobic fine particles and a suitable medium may be used instead. On the other hand, if the insulating fine particles (ultrafine aerogel particles) are hydrophilic, there is no need to use alcohol (ethanol), and water can be used as the medium in the first step (S1).
　調製されるスラリーにおいて、水、アルコール（例えばエタノール）、微粒子、結合剤（例えばＰＶＡ）の配合比率は、目的の仕様に応じて実験等によって最適化される。例えば、結合材であるＰＶＡの量は、多くすると微粒子の定着を高める一方、難燃性を下げる傾向にある。 The mixing ratio of water, alcohol (e.g. ethanol), fine particles, and binder (e.g. PVA) in the prepared slurry is optimized through experiments etc. according to the desired specifications. For example, increasing the amount of PVA as a binder increases the adhesion of the fine particles but tends to decrease flame retardancy.
　（ｂ）母材繊維６の表面に断熱性微粒子１を粉付けする難燃繊維の製造方法は、以下の各工程を含んで構成される。 (b) The method for producing a flame-retardant fiber in which insulating microparticles 1 are powdered onto the surface of the base fiber 6 includes the following steps:
　第５工程（Ｓ１５）：結合剤を溶かして結合剤溶液を調製する。Ｓ２，Ｓ１２と同様に、結合剤としては例えばＰＶＡ粉末が好適であり、ＰＶＡ粉末を常温の水に投入した後に約80℃に加熱し撹拌して溶かし、その後常温に戻す。
　第６工程（Ｓ１６）：母材繊維６に対して、第５工程（Ｓ１５）で調製した結合剤溶液を蒸発源として蒸着する。
　第７工程（Ｓ１７，粉付け工程）：第６工程（Ｓ１６）で結合剤溶液が表面に付着した母材繊維６に、断熱性微粒子１を機械的に塗す。機械的に塗すとは、母材繊維６の表面が濡れた状態、即ち蒸着された結合剤溶液がまだ乾いていない状態で、断熱性微粒子１と混ぜ合わせて撹拌することによって、結合剤溶液で濡れた母材繊維６の表面に断熱性微粒子１を付着させることを言う。 Fifth step (S15): Dissolve the binder to prepare a binder solution. As in S2 and S12, a suitable binder is, for example, PVA powder. The PVA powder is added to water at room temperature, heated to about 80°C, stirred to dissolve, and then returned to room temperature.
Sixth step (S16): The binder solution prepared in the fifth step (S15) is evaporated onto the base fiber 6 as an evaporation source.
Seventh step (S17, dusting step): The heat insulating fine particles 1 are mechanically applied to the base material fibers 6 on whose surfaces the binder solution has been applied in the sixth step (S16). "Mechanically applying" refers to mixing and stirring the heat insulating fine particles 1 while the surfaces of the base material fibers 6 are wet, i.e., while the evaporated binder solution is not yet dry, to cause the heat insulating fine particles 1 to adhere to the surfaces of the base material fibers 6 wet with the binder solution.
　母材繊維に難燃性を付加するための別の製造方法が提供される。 An alternative manufacturing method is provided for imparting flame retardancy to matrix fibers.
　母材繊維６の表面に断熱性微粒子１を蒸着する製造方法（ａ）と、母材繊維６の表面に断熱性微粒子１を粉付けする製造方法（ｂ）のいずれによっても、難燃繊維を製造することができる。実施形態４で説明したとおりの理由で、このときの断熱性微粒子１としては、エアロゲル超微粒子が特に好適である。 The flame-retardant fiber can be manufactured by either manufacturing method (a) in which the insulating fine particles 1 are vapor-deposited onto the surface of the base fiber 6, or manufacturing method (b) in which the insulating fine particles 1 are powdered onto the surface of the base fiber 6. For the reasons explained in embodiment 4, aerogel ultrafine particles are particularly suitable as the insulating fine particles 1 in this case.
　〔実施形態５〕
　本発明の一実施形態に係る難燃性を付加した断熱シート１００について説明する。図１に示した断熱シート１００において、母材繊維６の表面に断熱性微粒子１を含む難燃層３が形成されている。母材繊維６の表面をすべて覆うように、断熱性微粒子１を含む難燃層３を形成してもよいが、図３に示すように島状に難燃層３を形成しても難燃性を高める効果がある。 [Embodiment 5]
An insulating sheet 100 with added flame retardancy according to one embodiment of the present invention will be described. In the insulating sheet 100 shown in Fig. 1, a flame retardant layer 3 containing insulating fine particles 1 is formed on the surface of a matrix fiber 6. The flame retardant layer 3 containing insulating fine particles 1 may be formed so as to cover the entire surface of the matrix fiber 6, but forming the flame retardant layer 3 in an island shape as shown in Fig. 3 also has the effect of enhancing flame retardancy.
　難燃性を付加した断熱シート１００の製造方法について説明する。 This section describes a method for manufacturing a flame-retardant heat insulating sheet 100.
　図６は、難燃性が付加された断熱シートの製造方法の例を示すフローチャートである。 Figure 6 is a flow chart showing an example of a method for manufacturing a flame-retardant insulating sheet.
　実施形態４で示した母材繊維６の表面に断熱性微粒子１を蒸着する製造方法（ａ）または母材繊維６の表面に断熱性微粒子１を粉付けする製造方法（ｂ）によって製造された難燃繊維２００を母材繊維６として使って、実施形態１及び２で説明したのと同様の断熱シート１００を構成するために、以下の各工程を順次実施する。 The following steps are carried out in order to construct a heat insulating sheet 100 similar to that described in the first and second embodiments, using flame-retardant fiber 200 as base fiber 6, which is manufactured by manufacturing method (a) of vapor-depositing heat insulating microparticles 1 on the surface of base fiber 6 shown in embodiment 4, or manufacturing method (b) of powdering heat insulating microparticles 1 on the surface of base fiber 6.
　第８工程（Ｓ２１）：断熱性微粒子１を分散させて断熱性微粒子含有懸濁液を調製する。第１工程（Ｓ１１）で調製した断熱性微粒子含有懸濁液と同じでもよいし、抄紙工程（第１１工程，Ｓ２４）を考慮して、断熱性微粒子１の含有量の最適化を行ってもよい。
　第９工程（Ｓ２２）：ポリビニルアルコール粉末を水に溶かして繊維用の第２の結合剤溶液を調製する。第２工程（Ｓ１２）で調製した結合剤溶液でもよいし、抄紙工程（第１１工程，Ｓ２４）を考慮して、結合剤の濃度を最適化してもよい。
　第１０工程（Ｓ２３）：上記難燃繊維２００とバインダー繊維７と、第８工程（Ｓ２１）で調製した繊維用の第２の断熱性微粒子含有懸濁液と、第９工程（Ｓ２２）で調製した繊維用の第２の結合剤溶液とを混ぜて、繊維含有懸濁液を調製する。
　第１１工程（Ｓ２４）：第１０工程（Ｓ２３）の繊維含有懸濁液を抄く、抄紙工程である。 Eighth step (S21): A suspension containing heat insulating particles is prepared by dispersing heat insulating particles 1. The suspension containing heat insulating particles may be the same as the suspension containing heat insulating particles prepared in the first step (S11), or the content of the heat insulating particles 1 may be optimized in consideration of the papermaking step (eleventh step, S24).
Ninth step (S22): Prepare a second binder solution for the fibers by dissolving polyvinyl alcohol powder in water. This may be the binder solution prepared in the second step (S12), or the binder concentration may be optimized in consideration of the papermaking process (eleventh step, S24).
Tenth step (S23): The flame-retardant fiber 200, binder fiber 7, the second insulating microparticle-containing suspension for fibers prepared in the eighth step (S21), and the second binder solution for fibers prepared in the ninth step (S22) are mixed together to prepare a fiber-containing suspension.
Eleventh step (S24): This is a papermaking step in which the fiber-containing suspension of the tenth step (S23) is paper-made.
　これにより、難燃性が付加された断熱シートの製造方法を提供することができる。 This makes it possible to provide a method for manufacturing a heat insulating sheet with added flame retardant properties.
　本実施形態についても、実施形態１から４と同様に、断熱性微粒子１をエアロゲル超微粒子、母材繊維６をシリカ繊維、結合剤をポリビニルアルコールとすることができる。 In this embodiment, as in the first to fourth embodiments, the insulating microparticles 1 can be ultrafine aerogel particles, the matrix fibers 6 can be silica fibers, and the binder can be polyvinyl alcohol.
　母材繊維６をシリカ繊維とすることにより、実施形態１，２のように断熱シート１００を構成することができる。本実施形態３に示すように母材繊維６に難燃層３を接着することにより、難燃繊維２００を得ることができる。さらにこの難燃繊維を母材繊維６として使用することにより、断熱シート１００に難燃性を付加することができる。これにより、1000℃以上の高温の炎にも耐えることができる、断熱だけでなく耐熱性や難燃性を兼ね備えた断熱シートを実現することができる。このような断熱シートは、多数の電池セルを集積して構成される電池において、隣接する電池セルまたは電池モジュールの間を遮蔽して、熱暴走を防止するために利用することができる。 By using silica fiber as the base fiber 6, the insulating sheet 100 can be constructed as in the first and second embodiments. As shown in the third embodiment, the flame-retardant layer 3 can be bonded to the base fiber 6 to obtain the flame-retardant fiber 200. Furthermore, by using this flame-retardant fiber as the base fiber 6, flame retardancy can be added to the insulating sheet 100. This makes it possible to realize an insulating sheet that is not only insulating but also heat-resistant and flame-retardant, and can withstand high-temperature flames of 1000°C or more. Such an insulating sheet can be used to shield adjacent battery cells or battery modules in a battery composed of a large number of accumulated battery cells, thereby preventing thermal runaway.
　〔実施形態６〕
　本実施形態では、本発明に係る別の断熱シートの一実施形態について説明する。図１に示した断熱シート１００との違いは、図１１に示すように、断熱シートを構成する母材繊維３００に断熱性微粒子１４の少なくとも一部が埋設されている。すなわち、母材繊維３００は熱可塑性樹脂８からなる繊維であるが、この熱可塑性樹脂８中に断熱性微粒子１４が混合されて存在している。断熱性微粒子１４の粒子径が比較的大きい場合、及び／又は、断熱性微粒子１４の量が熱可塑性樹脂８の量に対して比較的多い場合、断熱性微粒子１４の一部が熱可塑性樹脂８から露出した状態で母材繊維３００表面に断熱性微粒子１４が存在する状態であってもよい。あるいは、断熱性微粒子１４の粒子径が、母材繊維３００の径よりも十分に小さい場合、又は、断熱性微粒子１４の量が熱可塑性樹脂８の量に対して比較的少ない場合には、断熱性微粒子１４が完全に熱可塑性樹脂８中に埋没されて母材繊維３００表面には断熱性微粒子１４が存在しない状態であってもよい。 [Embodiment 6]
In this embodiment, another embodiment of the heat insulating sheet according to the present invention will be described. The difference from the heat insulating sheet 100 shown in FIG. 1 is that, as shown in FIG. 11, at least a part of the heat insulating fine particles 14 is embedded in the matrix fiber 300 constituting the heat insulating sheet. That is, the matrix fiber 300 is a fiber made of a thermoplastic resin 8, and the heat insulating fine particles 14 are mixed and present in the thermoplastic resin 8. When the particle diameter of the heat insulating fine particles 14 is relatively large and/or when the amount of the heat insulating fine particles 14 is relatively large compared to the amount of the thermoplastic resin 8, the heat insulating fine particles 14 may be present on the surface of the matrix fiber 300 with a part of the heat insulating fine particles 14 exposed from the thermoplastic resin 8. Alternatively, when the particle diameter of the heat insulating fine particles 14 is sufficiently smaller than the diameter of the matrix fiber 300, or when the amount of the heat insulating fine particles 14 is relatively small compared to the amount of the thermoplastic resin 8, the heat insulating fine particles 14 may be completely embedded in the thermoplastic resin 8 and no heat insulating fine particles 14 may be present on the surface of the matrix fiber 300.
　熱可塑性樹脂としては、例えば、ポリエチレンテレフタレート（ＰＥＴ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリアルキレンテレフタレートを主体とした芳香族ポリエステル、ポリ乳酸などの脂肪族ポリエステルポリ乳酸などのポリエステルの他、ポリアミド、ポリウレタン、ポリオレフィン等、化学繊維の材料として用いることが可能な公知の熱可塑性樹脂が挙げられる。これらの熱可塑性樹脂は単独で又は二種類以上を混合して使用することができる。 Thermoplastic resins include, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), aromatic polyesters mainly composed of polyalkylene terephthalate, aliphatic polyesters such as polylactic acid, polyesters such as polylactic acid, as well as known thermoplastic resins that can be used as materials for chemical fibers, such as polyamide, polyurethane, polyolefin, etc. These thermoplastic resins can be used alone or in a mixture of two or more types.
　また、熱可塑性樹脂として、例えば、ペットボトル等の熱可塑性樹脂成形品を再溶融しペレットや粉体に成形したリサイクル樹脂を使用してもよい。 Furthermore, recycled resins made by remelting thermoplastic resin molded products such as PET bottles and molding them into pellets or powder may be used as the thermoplastic resin.
　本実施形態の断熱シートは、前記母材繊維３００が紡糸された糸が織編みされて構成されている。母材繊維３００は、後述する任意の公知の紡糸方法で紡糸されることができる。 The heat insulating sheet of this embodiment is constructed by weaving and knitting threads spun from the base fiber 300. The base fiber 300 can be spun by any known spinning method described below.
　また、糸は任意の公知の方法で織編みされることができる。本実施形態において「織編み」とは、織物を形成するために糸を織ること、または編組織を形成するために糸を編むことを意味する。織物としては、平、ツイル、サテン、アムンゼン、二重織物等の公知の任意の組織が挙げられる。編組織としては、天竺やスムース、ハーフ、ダブルラッセル等の公知の任意の編組織が挙げられる。 The yarns may also be woven or knitted in any known manner. In this embodiment, "woven" refers to weaving yarns to form a woven fabric, or knitting yarns to form a knitted fabric. Woven fabrics include any known weaves, such as plain, twill, satin, amundsen, and double weave. Knitted fabrics include any known knitted fabrics, such as jersey, smooth, half, and double raschel.
　本実施形態の断熱シートは、母材繊維３００中に断熱性微粒子１４が混合されている糸を織編みされているため、結合剤で断熱性微粒子１４を担持することなく、断熱性の高い断熱シートが得られる。 The insulating sheet of this embodiment is made by weaving and knitting yarn in which insulating particles 14 are mixed into the base fiber 300, so a highly insulating sheet can be obtained without the insulating particles 14 being supported by a binder.
　〔実施形態７〕
　本実施形態では、本発明に係る別の断熱シートの一実施形態について説明する。本実施形態の断熱シートは、前記実施形態６で示した母材繊維３００と同様の母材繊維を用いる。すなわち、前記母材繊維は、熱可塑性樹脂を含み、断熱性微粒子は前記母材繊維の熱可塑性樹脂中に少なくとも一部が埋設された状態で存在し、シート体は、前記母材繊維が、前記熱可塑性樹脂が溶けてできた膜で互いに接着されることで形成されている断熱シートである。 [Embodiment 7]
In this embodiment, another embodiment of the heat insulating sheet according to the present invention will be described. The heat insulating sheet of this embodiment uses the same base material fiber as the base material fiber 300 shown in the above-mentioned embodiment 6. That is, the base material fiber contains a thermoplastic resin, the heat insulating fine particles are present in a state where at least a part of them is embedded in the thermoplastic resin of the base material fiber, and the sheet body is a heat insulating sheet formed by bonding the base material fibers to each other with a film formed by melting the thermoplastic resin.
　本実施形態の母材繊維は、熱可塑性樹脂を含むため、熱などで容易に溶融させることができるため、バインダー繊維を用いることなく、母材繊維同士を熱可塑性樹脂が溶けてできた膜で互いに接着し、シート状に形成することができる。また、実施形態６と同様に、母材繊維中に断熱性微粒子が混合されているため、結合剤で断熱性微粒子を担持することなく、断熱性の高い断熱シートが得られる。 The base fiber in this embodiment contains a thermoplastic resin and can be easily melted by heat, etc., so that the base fibers can be bonded together with a film made by melting the thermoplastic resin and formed into a sheet without using binder fibers. Also, as in embodiment 6, insulating fine particles are mixed into the base fiber, so a highly insulating sheet can be obtained without carrying the insulating fine particles with a binder.
　一方、本実施形態の母材繊維を、実施形態１における母材繊維の代替として使用して、実施形態２の製造方法によって、断熱シートを作成してもよい。即ち、母材繊維として熱可塑性樹脂に断熱性微粒子の少なくとも一部が埋設された繊維を用い、ＰＶＡ繊維と結合剤とさらに、断熱性微粒子を含む懸濁液を用いた抄紙工程によって、断熱シートを製造する。母材繊維が断熱性微粒子を含んでいるため、より高い断熱性能を得ることができる。 On the other hand, the matrix fibers of this embodiment may be used as a substitute for the matrix fibers of embodiment 1 to produce an insulating sheet by the manufacturing method of embodiment 2. That is, fibers in which at least some of the insulating microparticles are embedded in a thermoplastic resin are used as the matrix fibers, and the insulating sheet is produced by a papermaking process using PVA fibers, a binder, and a suspension containing the insulating microparticles. Since the matrix fibers contain the insulating microparticles, higher insulating performance can be obtained.
　〔実施形態８〕
　本実施形態では、本発明に係る別の断熱シートの製造方法の一実施形態について説明する。 [Embodiment 8]
In this embodiment, another embodiment of a method for producing a heat insulating sheet according to the present invention will be described.
　本実施形態の製造方法は、上記実施形態６及び７で示した断熱シートを製造する方法の一例としても挙げられる。本実施形態の断熱シートの製造方法は、図１２に例示されるように、以下の各工程を含んで構成される。 The manufacturing method of this embodiment can also be cited as an example of a method for manufacturing the heat insulating sheets shown in the above-mentioned embodiments 6 and 7. As illustrated in FIG. 12, the manufacturing method of the heat insulating sheet of this embodiment includes the following steps.
　第１２工程（Ｓ２５）：熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を得る工程。
　第１３工程（Ｓ２６）：前記微粒子含有樹脂を、細孔を有する容器に収容し、前記容器を加熱しながら回転させて前記細孔から前記微粒子含有樹脂を噴出させ短繊維を得る工程。
　第１４工程（Ｓ２７）：前記短繊維をシート状に成形する工程。 Twelfth step (S25): A step of mixing a thermoplastic resin and heat insulating fine particles to obtain a fine particle-containing resin.
Thirteenth step (S26): A step of placing the microparticle-containing resin in a container having fine holes, rotating the container while heating it, and ejecting the microparticle-containing resin from the fine holes to obtain short fibers.
Fourteenth step (S27): A step of forming the short fibers into a sheet shape.
　第１２工程では、熱可塑性樹脂を加熱して溶融させてその中に断熱性微粒子を添加し、加熱しながら撹拌して混合することによって、予め、微粒子含有樹脂を調製しておき、それを砕いて前記容器に投入して改めて溶融しても良い。これにより、熱可塑性樹脂の中の断熱性微粒子は、比較的均一に分散される。 In the 12th step, the thermoplastic resin is heated and melted, and the insulating microparticles are added thereto, and the mixture is stirred and mixed while being heated to prepare a microparticle-containing resin. The resin may then be crushed and placed in the container and melted again. This allows the insulating microparticles in the thermoplastic resin to be dispersed relatively uniformly.
　あるいは、溶融させた熱可塑性樹脂と断熱性微粒子とを共に容器等に入れることで微粒子含有樹脂を得てもよい。この場合、熱可塑性樹脂と断熱性微粒子とは完全に混合されていない状態で微粒子含有樹脂が構成される。 Alternatively, the microparticle-containing resin may be obtained by placing the molten thermoplastic resin and the insulating microparticles together in a container or the like. In this case, the thermoplastic resin and the insulating microparticles are not completely mixed together to form the microparticle-containing resin.
　第１３工程では、図１３に示すように、第１２工程で得られた微粒子含有樹脂９を、チャンバーＣに配置された細孔を有する容器４００に収容し、前記容器４００を加熱しながらモーターＭを駆動して回転させ前記容器４００の細孔から前記微粒子含有樹脂９を遠心力によって噴出させ、チャンバーＣの内壁に吹き付けながら短繊維を得る。微粒子含有樹脂は、溶融させた熱可塑性樹脂と断熱性微粒子とを共に第１３工程で使用する細孔を有する容器に直接入れることで得てもよい。この場合第１２工程と第１３工程を同時に実施することになる。 In step 13, as shown in FIG. 13, the microparticle-containing resin 9 obtained in step 12 is placed in a container 400 with fine holes arranged in chamber C, and while the container 400 is heated, motor M is driven to rotate the container, causing the microparticle-containing resin 9 to be ejected from the fine holes in the container 400 by centrifugal force, and the resin is sprayed against the inner wall of chamber C to obtain short fibers. The microparticle-containing resin may be obtained by directly putting the molten thermoplastic resin and the insulating microparticles together into the container with fine holes used in step 13. In this case, steps 12 and 13 are carried out simultaneously.
　容器はモーターＭと回転軸４０１で連結され、モーターＭの駆動によって回転軸４０１を中心に回転可能に設けられている。また、容器４００の側壁には容器内部と外部とを連通する細孔が複数設けられている。かかる容器４００を、下方に設置されたヒーターＨで加熱し内部の微粒子含有樹脂９を溶解させ、この状態でモーターＭを駆動して回転させる。容器４００内部の微粒子含有樹脂９には回転による遠心力が作用し、微粒子含有樹脂９は容器４００の細孔から噴出されることによって急冷されて繊維状になり、チャンバーＣの内壁に短い繊維状になって吹き付けられる。チャンバーＣの内壁に吹き付けられた短繊維は、短繊維同士が絡まりあっている繊維（綿状の繊維）５００となっている。 The container is connected to motor M by a rotating shaft 401, and is rotatable around the rotating shaft 401 by driving motor M. The side wall of container 400 has a number of fine holes that connect the inside and outside of the container. The container 400 is heated by heater H installed below to melt the microparticle-containing resin 9 inside, and in this state, motor M is driven to rotate it. Centrifugal force due to rotation acts on the microparticle-containing resin 9 inside container 400, and the microparticle-containing resin 9 is rapidly cooled and turned into fibers by being ejected from the fine holes in container 400, and is sprayed in the form of short fibers onto the inner wall of chamber C. The short fibers sprayed onto the inner wall of chamber C become fibers (cotton-like fibers) 500 in which the short fibers are entangled with each other.
　第１４工程では、得られた短繊維５００をシート状に成形する。短繊維は熱可塑性樹脂を含むため、加熱により容易に変形できる。従って、例えば、綿状の繊維を加熱しながらシート状に成形することで容易にシート状に形成することができる。あるいは、かかる短繊維を実施形態６のように公知の紡糸方法で紡糸し、糸として織編みすることでシート状に形成することも可能である。 In step 14, the obtained short fibers 500 are formed into a sheet. Since the short fibers contain a thermoplastic resin, they can be easily deformed by heating. Therefore, for example, the cotton-like fibers can be easily formed into a sheet by heating and forming them into a sheet. Alternatively, such short fibers can be spun by a known spinning method as in embodiment 6, and woven and knitted into yarn to form a sheet.
　〔実施形態９〕
　本実施形態では、本発明に係る別の断熱シートの製造方法の一実施形態について説明する。 [Embodiment 9]
In this embodiment, another embodiment of a method for producing a heat insulating sheet according to the present invention will be described.
　本実施形態の製造方法は、上記実施形態６で示した断熱シートを製造する方法の一例としても挙げられる。本発明のさらに別の実施の形態である断熱シートの製造方法は、図１４に例示されるように、以下の各工程を含んで構成される。 The manufacturing method of this embodiment can also be cited as an example of a method for manufacturing the heat insulating sheet shown in embodiment 6 above. A manufacturing method of a heat insulating sheet according to yet another embodiment of the present invention includes the following steps, as illustrated in FIG. 14.
　第１５工程（Ｓ２８）：熱可塑性樹脂を溶融し、該溶融された熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を調製する工程。
　第１６工程（Ｓ２９）：溶融された前記微粒子含有樹脂を細孔から押し出して繊維を得る工程。
　第１７工程（Ｓ３０）：前記繊維を紡糸して糸を得る工程。
　第１８工程（Ｓ３１）：前記糸を織編みする工程。 Fifteenth step (S28): A step of melting a thermoplastic resin and mixing the melted thermoplastic resin with heat insulating fine particles to prepare a fine particle-containing resin.
Sixteenth step (S29): A step of extruding the molten microparticle-containing resin through pores to obtain fibers.
Seventeenth step (S30): A step of spinning the fiber to obtain yarn.
18th step (S31): A step of weaving and knitting the yarn.
　第１５工程は、前記実施形態８の第１２工程（図１２のＳ２５）と同様に実施できる。 Step 15 can be performed in the same manner as step 12 of embodiment 8 (S25 in FIG. 12).
　第１６工程は、溶融された前記微粒子含有樹脂を細孔から押し出して繊維を得る。押し出して繊維を得る方法には、例えば、図１５に示すような紡糸装置６００を用いて冷却雰囲気中（冷風を吹き付ける）に溶融状態の微粒子含有樹脂６０１を押し出し複数の繊維とし、かかる繊維に撚りをかけて紡糸する方法（溶融紡糸方法）や、冷却雰囲気ではなく凝固液中に微粒子含有樹脂を押し出す方法（湿式紡糸法）や、冷却雰囲気ではなく加熱雰囲気中に微粒子含有樹脂を押し出す方法（乾式紡糸方法）等の公知の化学繊維の紡糸方法で行うことが可能である。 In step 16, the molten microparticle-containing resin is extruded through the pores to obtain fibers. Methods for obtaining fibers by extrusion include, for example, a method in which molten microparticle-containing resin 601 is extruded into a cooling atmosphere (by blowing cold air) using a spinning device 600 as shown in FIG. 15 to form multiple fibers, which are then twisted and spun (melt spinning method), a method in which microparticle-containing resin is extruded into a solidifying liquid rather than a cooling atmosphere (wet spinning method), and a method in which microparticle-containing resin is extruded into a heated atmosphere rather than a cooling atmosphere (dry spinning method).
　第１７及び１８工程は、実施形態６と同様に実施できる。 Steps 17 and 18 can be carried out in the same manner as in embodiment 6.
〔実施例１〕
　シリカ繊維であるグラスウールに、実施形態４～５で説明したように、エアロゲル超微粒子を接着して難燃層を形成し、難燃層を形成しないグラスウールと比較した。 Example 1
As explained in the fourth and fifth embodiments, ultrafine aerogel particles were adhered to glass wool, which is a silica fiber, to form a flame-retardant layer, and the flame-retardant layer was compared with glass wool that did not have a flame-retardant layer.
　１枚のグラスウールブランケットから同じ厚さの試料を切り出し、難燃層を形成しないグラスウールブランケット試料と、難燃層を形成したグラスウールブランケット試料とを作成し、一方の面からColeman製ミニトーチ170-9105を用いて1300℃の炎で60秒間炙り、炙った面とその反対面を肉眼及び光学顕微鏡で観察した。 Samples of the same thickness were cut out from a single glass wool blanket to create a glass wool blanket sample without a flame-retardant layer and a glass wool blanket sample with a flame-retardant layer. One side was heated with a Coleman mini torch 170-9105 for 60 seconds over a 1300°C flame, and the heated side and the opposite side were observed with the naked eye and an optical microscope.
　図９は、実物の写真である。難燃層を形成しないグラスウールブランケット試料（左側）は、炎で炙った面（Hot side）は融けており、その反対面（Cold side）も炙られた中央部が薄くなっている様子が観察される。一方、難燃層を形成したグラスウールブランケット試料（右側）は、炎で炙った面（Hot side）に窪みが観察されるものの、その反対面（Cold side）には変化がない。 Figure 9 is a photograph of the actual product. The glass wool blanket sample without a flame-retardant layer (left side) has melted on the surface that was heated by the flame (hot side), and the opposite surface (cold side) has also been observed to have thinned in the center where it was heated. On the other hand, the glass wool blanket sample with a flame-retardant layer (right side) has a dent observed on the surface that was heated by the flame (hot side), but there is no change on the opposite surface (cold side).
　図１０は、光学顕微鏡写真である。難燃層を形成しないグラスウールブランケット試料（左側）のHot sideの炎で炙られた部分は、繊維が融けたことが観察されるが、難燃層を形成したグラスウールブランケット試料（右側）は、炎で炙る前からほとんど変化が見られない。 Figure 10 is an optical microscope photograph. It can be seen that the fibers have melted in the area of the glass wool blanket sample (left side) that does not form a flame-retardant layer, but the glass wool blanket sample (right side) that does form a flame-retardant layer shows almost no change from before it was heated by the flame.
　以上のように、エアロゲル超微粒子を接着して難燃層を形成することによって、母材繊維に難燃性が付加される。
〔実施例２〕
　実施形態８に示した断熱シートの製造方法で用いられる短繊維の製造を以下の方法で行った。
（材量）
　ペットボトルのカット片
　エアロゲル超微粒子（商品名：ＴＩＩＳＡ、株式会社Thermalytica製）
（微粒子含有樹脂の作製方法）
　ペットボトルのカット片とエアロゲル超微粒子をステンレスカップに入れ、アルコールランプで加熱しながらペットボトル片が完全に溶融するまで攪拌し、加熱を止めて室温まで冷却し、微粒子含有樹脂を得た。 As described above, by forming a flame-retardant layer by adhering ultrafine aerogel particles, flame retardancy is imparted to the base fiber.
Example 2
The staple fibers used in the method for producing a heat insulating sheet shown in embodiment 8 were produced by the following method.
(Material amount)
Cut pieces of PET bottles Ultrafine aerogel particles (product name: TIISA, manufactured by Thermalytica Inc.)
(Method of producing fine particle-containing resin)
The cut pieces of the PET bottle and ultrafine aerogel particles were placed in a stainless steel cup and stirred while being heated with an alcohol lamp until the pieces of the PET bottle were completely melted. Heating was then stopped and the mixture was cooled to room temperature to obtain a resin containing fine particles.
　微粒子含有樹脂中のエアロゲル超微粒子の含有量は、１質量％、３質量％、４質量％、及びコントロールとしてエアロゲル超微粒子なし（０質量％）になるように調整した。冷却された微粒子含有樹脂をハンマーで叩き固まりを砕いた。
（短繊維の作製方法）
　３５０ｍｌの飲料用アルミニウム製ボトルの側面に、ドリルで細孔を開け、図１６に示すような装置にセットした。細孔のサイズは２ｍｍである。 The content of ultrafine aerogel particles in the fine particle-containing resin was adjusted to 1 mass %, 3 mass %, 4 mass %, and as a control, no ultrafine aerogel particles (0 mass %). The cooled fine particle-containing resin was hit with a hammer to break up lumps.
(Method of Producing Short Fibers)
A small hole was drilled in the side of a 350 ml aluminum beverage bottle, and the bottle was set in the apparatus shown in Figure 16. The size of the small hole was 2 mm.
　各微粒子含有樹脂をボトルに入れ、ブンセンバーナーで加熱しながらモーターを駆動し、ボトルを回転させた。回転速度は1493rpm（モーター電圧0.7V）である。ボトルを回転させながらボトル内の微粒子含有樹脂を細孔から噴出させ、ボックスの内壁に付着した綿状の短繊維を回収した。
（短繊維の観察）
　回収された短繊維を以下のように観察した。 Each resin containing fine particles was placed in a bottle, and while heating it with a Bunsen burner, a motor was driven to rotate the bottle. The rotation speed was 1493 rpm (motor voltage 0.7 V). While rotating the bottle, the resin containing fine particles in the bottle was ejected from the pores, and the cotton-like short fibers attached to the inner wall of the box were collected.
(Observation of Short Fibers)
The recovered short fibers were observed as follows.
　短繊維から数本の繊維を取り、直径約２０ｍｍ、高さ２０ｍｍの円柱形プラスチック容器内で直立するように固定した。エポキシと硬化剤を均一に混合した混合物を容器内に注ぎ、混合物を硬化させ、繊維サンプルを完全に固定した。エポキシが硬化したら、繊維サンプルを容器ごと側面から薄く切断し、切断面を研磨した。観察する表面をプラチナでコーティングして導電性を付与し、ＳＥＭ観察用のサンプルを得た。かかるサンプルを、ショットキー電界放出形走査電子顕微鏡（JSM-7900F、日本電子株式会社製）で観察した。 Several fibers were taken from the short fibers and fixed upright in a cylindrical plastic container with a diameter of approximately 20 mm and a height of 20 mm. A homogeneous mixture of epoxy and hardener was poured into the container, and the mixture was allowed to harden, completely fixing the fiber sample. Once the epoxy had hardened, the fiber sample was cut thinly from the side together with the container, and the cut surface was polished. The surface to be observed was coated with platinum to make it conductive, and a sample for SEM observation was obtained. The sample was observed with a Schottky field emission scanning electron microscope (JSM-7900F, manufactured by JEOL Ltd.).
　観察の結果を図１７に示す。図１７中の、２００倍の各写真において白い丸で囲んだ部分が短繊維の断面である。１０００倍の各写真において黒い丸で囲んだ部分が短繊維中のエアロゲル超微粒子である。１０００倍の写真の１質量％、４質量％の繊維では、エアロゲル超微粒子を含まないコントロールの繊維には表れていない白い塊が見え、これはエアロゲル超微粒子を示しており、従って、エアロゲル超微粒子を内部に含んだ繊維が得られたことを示す。 The results of the observation are shown in Figure 17. In Figure 17, the areas surrounded by white circles in each of the 200x photographs are the cross sections of the short fibers. In each of the 1000x photographs, the areas surrounded by black circles are the ultrafine aerogel particles in the short fibers. In the 1000x photographs, white lumps are visible in the 1% and 4% by mass fibers that are not visible in the control fibers that do not contain ultrafine aerogel particles, and these indicate ultrafine aerogel particles, and therefore indicate that fibers containing ultrafine aerogel particles inside have been obtained.
　以上本発明者によってなされた発明を実施形態に基づいて具体的に説明したが、本発明はそれに限定されるものではなく、その要旨を逸脱しない範囲において種々変更可能であることは言うまでもない。 　The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the invention is not limited thereto and can be modified in various ways without departing from the gist of the invention.
　本発明は、断熱シート及びその製造方法、断熱繊維及びその製造方法、並びに断熱シートの製造に用いられる繊維含有懸濁液に好適に利用することができる。 The present invention can be suitably used for heat insulating sheets and manufacturing methods thereof, heat insulating fibers and manufacturing methods thereof, and fiber-containing suspensions used in the manufacture of heat insulating sheets.
　１　断熱性微粒子（例えば、エアロゲル超微粒子）
　２　結合剤（例えば、ＰＶＡ）
　３　難燃層
　４　結合剤層
　６　母材繊維（例えば、シリカ繊維）
　７　バインダー繊維（例えば、ＰＶＡ繊維）
　８　熱可塑性樹脂
　９　微粒子含有樹脂
　１１　一次粒子
　１２　二次粒子（一次粒子の集合体、クラスター）
　１３　エアロゲル微粉末（二次粒子による骨格が形成された粉末）
　１４　一次粒子によって骨格が形成された微粒子（例えば、エアロゲル超微粒子）
　１００　断熱シート
　２００　難燃繊維
　３００　母材繊維 1. Heat insulating fine particles (e.g., ultrafine aerogel particles)
2. Binder (e.g., PVA)
3 Flame retardant layer 4 Binder layer 6 Base fiber (e.g., silica fiber)
7 Binder fiber (e.g., PVA fiber)
8 Thermoplastic resin 9 Microparticle-containing resin 11 Primary particle 12 Secondary particle (aggregate of primary particles, cluster)
13. Aerogel fine powder (powder with a skeleton formed by secondary particles)
14. Fine particles whose skeleton is formed by primary particles (e.g., ultrafine aerogel particles)
100 Heat insulating sheet 200 Flame retardant fiber 300 Base fiber

Claims (24)

  1. 　母材繊維と断熱性微粒子とを含む断熱シートであって、
    　前記母材繊維は互いに接着され又は織編みされてシート体を形成し、
    　前記断熱性微粒子は、前記母材繊維の内部又は／及び外側に存在している、
    　断熱シート。     A heat insulating sheet comprising matrix fibers and heat insulating particles,
    The matrix fibers are bonded or woven together to form a sheet body;
    The heat insulating fine particles are present inside and/or outside the base material fibers.
    Insulating sheet.
  2. 　請求項１において、
    　前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子である、
    　断熱シート。     In claim 1,
    The heat insulating fine particles are made of aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less.
    Insulating sheet.
  3. 　請求項１又は２において、
    　前記母材繊維はシリカ繊維であって、
    　前記シート体は、前記母材繊維とバインダー繊維と結合剤とを含み、
    　前記母材繊維は、前記バインダー繊維が溶けてできた膜で互いに接着され、接着された前記母材繊維の隙間に、前記結合剤によって断熱性微粒子が担持される、
    　断熱シート。     In claim 1 or 2,
    The matrix fiber is a silica fiber,
    The sheet body includes the base fiber, a binder fiber, and a binder,
    The base material fibers are bonded to each other by a film formed by dissolving the binder fibers, and the heat insulating particles are supported in the gaps between the bonded base material fibers by the binder.
    Insulating sheet.
  4. 　請求項３において、
    　前記母材繊維の表面には、前記断熱性微粒子が前記結合剤によって接着されている、
    　断熱シート。     In claim 3,
    The heat insulating particles are bonded to the surface of the base fiber by the binder.
    Insulating sheet.
  5. 　請求項１又は２において、
    　前記母材繊維は、熱可塑性樹脂を含み、
    　前記断熱性微粒子は前記母材繊維中の前記熱可塑性樹脂に少なくとも一部が埋設された状態で存在し、
    　前記シート体は、前記母材繊維が紡糸された糸が織編みされて構成されている、
    　断熱シート。     In claim 1 or 2,
    The matrix fibers include a thermoplastic resin,
    the heat insulating fine particles are present in a state where at least a part of them is embedded in the thermoplastic resin in the matrix fiber,
    The sheet body is formed by weaving and knitting yarns spun from the base fiber.
    Insulating sheet.
  6. 　請求項１又は２において、
    　前記母材繊維は、熱可塑性樹脂を含み、
    　前記断熱性微粒子は前記母材繊維の前記熱可塑性樹脂に少なくとも一部が埋設された状態で存在し、
    　前記シート体は、前記母材繊維が、前記熱可塑性樹脂が溶けてできた膜で互いに接着されることで形成されている、
    　断熱シート。     In claim 1 or 2,
    The matrix fibers include a thermoplastic resin,
    The heat insulating fine particles are present in a state where at least a part of the fine particles is embedded in the thermoplastic resin of the base fiber,
    The sheet body is formed by bonding the base fibers to each other with a film formed by melting the thermoplastic resin.
    Insulating sheet.
  7. 　断熱シートの製造方法であって、
    　断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程と、
    　結合剤を溶かして結合剤溶液を調製する工程と、
    　前記断熱性微粒子含有懸濁液と、前記結合剤溶液と、母材繊維と、バインダー繊維とを混ぜて繊維含有懸濁液を調製する工程と、
    　前記繊維含有懸濁液から液体成分を除いてシート体を形成する工程と、を含む、
    　断熱シートの製造方法。     A method for producing a heat insulating sheet, comprising:
    A step of dispersing heat insulating fine particles to prepare a heat insulating fine particle-containing suspension;
    Dissolving a binder to prepare a binder solution;
    A step of preparing a fiber-containing suspension by mixing the heat insulating microparticle-containing suspension, the binder solution, base material fibers, and binder fibers;
    and removing the liquid component from the fiber-containing suspension to form a sheet body.
    A method for manufacturing a heat insulating sheet.
  8. 　請求項７において、
    　前記母材繊維はシリカ繊維であり、
    　前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子である、
    　断熱シートの製造方法。     In claim 7,
    the matrix fibers are silica fibers;
    The heat insulating fine particles are made of aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less.
    A method for manufacturing a heat insulating sheet.
  9. 　請求項７又は８において、
    　前記断熱性微粒子が疎水性であって、前記断熱性微粒子含有懸濁液は、アルコールを含む、
    　断熱シートの製造方法。     In claim 7 or 8,
    The heat insulating fine particles are hydrophobic, and the heat insulating fine particle-containing suspension contains alcohol.
    A method for manufacturing a heat insulating sheet.
  10. 　断熱シートの製造方法であって、
    　熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を得る工程と、
    　前記微粒子含有樹脂を、細孔を有する容器に収容し、前記容器を加熱しながら回転させて前記細孔から前記微粒子含有樹脂を噴出させて短繊維を得る工程と、
    　前記短繊維をシート状に成形する工程と、を含む、
    　断熱シートの製造方法。     A method for producing a heat insulating sheet, comprising:
    A step of mixing a thermoplastic resin and heat insulating fine particles to obtain a fine particle-containing resin;
    a step of placing the microparticle-containing resin in a container having fine holes, rotating the container while heating it, and ejecting the microparticle-containing resin from the fine holes to obtain short fibers;
    and forming the short fibers into a sheet.
    A method for manufacturing a heat insulating sheet.
  11. 　請求項１０において、
    　前記短繊維を紡糸して糸を得る工程と、
    　前記糸を織編みする工程と、を含む、
    　断熱シートの製造方法。     In claim 10,
    A step of spinning the staple fibers to obtain yarn;
    and weaving and knitting the yarn.
    A method for manufacturing a heat insulating sheet.
  12. 　請求項１０において、
    　前記短繊維をシート状に成形する工程において、前記短繊維を薄膜状に広げ、加熱することでシート状に成形する、
    　断熱シートの製造方法。     In claim 10,
    In the step of forming the short fibers into a sheet, the short fibers are spread into a thin film and heated to form the sheet.
    A method for manufacturing a heat insulating sheet.
  13. 　断熱シートの製造方法であって、
    　熱可塑性樹脂を溶融し、該溶融された熱可塑性樹脂と断熱性微粒子とを混合して微粒子含有樹脂を調製する工程と、
    　前記溶融された前記微粒子含有樹脂を細孔から押し出して繊維を得る工程と、
    　前記繊維を紡糸して糸を得る工程と、
    　前記糸を織編みする工程と、を含む、
    　断熱シートの製造方法。     A method for producing a heat insulating sheet, comprising:
    A step of melting a thermoplastic resin and mixing the melted thermoplastic resin with heat insulating fine particles to prepare a fine particle-containing resin;
    a step of extruding the molten microparticle-containing resin through pores to obtain fibers;
    spinning the fibers to obtain yarn;
    and weaving and knitting the yarn.
    A method for manufacturing a heat insulating sheet.
  14. 　断熱シートの製造方法であって、
    　断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程と、
    　結合剤を溶かして結合剤溶液を調製する工程と、
    　断熱繊維と、バインダー繊維と、前記断熱性微粒子含有懸濁液と、前記結合剤溶液とを混ぜて繊維含有懸濁液を調製する工程と、
    　前記繊維含有懸濁液から液体成分を除いてシート体を形成する工程と、を含み、
    　前記断熱繊維は、
    　母材繊維の表面に繊維用の断熱性微粒子が繊維用の結合剤によって接着され、
    　前記繊維用の断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり
    　前記母材繊維はシリカ繊維である、
    　断熱シートの製造方法。     A method for producing a heat insulating sheet, comprising:
    A step of dispersing heat insulating fine particles to prepare a heat insulating fine particle-containing suspension;
    Dissolving a binder to prepare a binder solution;
    A step of preparing a fiber-containing suspension by mixing heat insulating fibers, binder fibers, the heat insulating microparticle-containing suspension, and the binder solution;
    and removing the liquid component from the fiber-containing suspension to form a sheet body,
    The insulating fiber is
    The insulating particles for the fibers are bonded to the surface of the base fiber by a binder for the fibers,
    The insulating fine particles for the fibers are made of aerogel having a three-dimensional network structure with a skeleton composed of clusters that are aggregates of primary particles, and have a three-dimensional network structure with a skeleton composed of the primary particles, and 50% or more of the volume of the fine particles are dispersed with a mode of particle diameter of 0.1 μm to 1.0 μm, and the base fiber is silica fiber.
    A method for manufacturing a heat insulating sheet.
  15. 　請求項１４において、
    　前記母材繊維の表面に繊維用の断熱性微粒子及び繊維用の結合剤は超音波蒸着または加熱蒸着により蒸着される、
    　断熱シートの製造方法。     In claim 14,
    The insulating particles for fibers and the binder for fibers are deposited on the surface of the base fiber by ultrasonic deposition or thermal deposition;
    A method for manufacturing a heat insulating sheet.
  16. 　請求項１４において、
    　前記断熱性微粒子が疎水性であって、前記断熱性微粒子含有懸濁液は、アルコールを含む、
    　断熱シートの製造方法。     In claim 14,
    The heat insulating fine particles are hydrophobic, and the heat insulating fine particle-containing suspension contains alcohol.
    A method for manufacturing a heat insulating sheet.
  17. 　断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、母材繊維と、バインダー繊維とが混合された断熱シートの製造用の繊維含有懸濁液。 A fiber-containing suspension for manufacturing insulating sheets, which is a mixture of insulating microparticle-containing suspension in which insulating microparticles are dispersed in a solvent, a binder solution, base fibers, and binder fibers.
  18. 　断熱性微粒子を溶媒に分散させた断熱性微粒子含有懸濁液と、結合剤溶液と、断熱繊維と、バインダー繊維とが混合され、
    　前記断熱繊維は、
    　母材繊維の表面に繊維用の断熱性微粒子が繊維用の結合剤によって接着され、
    　前記繊維用の断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、
    　前記母材繊維はシリカ繊維である、
    　断熱シートの製造用の繊維含有懸濁液。     A suspension containing heat insulating fine particles, in which heat insulating fine particles are dispersed in a solvent, is mixed with a binder solution, heat insulating fibers, and binder fibers,
    The insulating fiber is
    The insulating particles for the fibers are bonded to the surface of the base fiber by a binder for the fibers,
    The insulating fine particles for fibers are made of aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less;
    The matrix fibers are silica fibers.
    Fiber-containing suspension for the production of insulating sheets.
  19. 　断熱繊維であって、
    　母材繊維の表面に断熱性微粒子が結合剤によって接着され、
    　前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、
    　前記母材繊維はシリカ繊維である、
    　断熱繊維。     An insulating fiber,
    The insulating particles are bonded to the surface of the matrix fibers by a binder.
    The heat insulating fine particles are made from an aerogel having a three-dimensional network structure with a skeleton formed of clusters that are aggregates of primary particles, and are fine particles having a three-dimensional network structure with a skeleton formed of the primary particles, with 50% or more of the volume of the fine particles being dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less,
    The matrix fibers are silica fibers.
    Insulating fiber.
  20. 　断熱繊維であって、
    　母材繊維の内部に、断熱性微粒子が少なくとも一部が埋設された状態で存在し
    　前記断熱性微粒子は、一次粒子の集合体であるクラスターで骨格を構成された三次元網目構造を有するエアロゲルを原料とし、前記一次粒子で骨格を構成された三次元網目構造を有し、その体積の50％以上が粒子径について0.1μm以上1.0μm以下に最頻値をもって分散する微粒子であり、
    　前記母材繊維は熱可塑性樹脂を含む、
    　断熱繊維。     An insulating fiber,
    The insulating fine particles are present in a state where at least a part of them is embedded inside the matrix fiber, the insulating fine particles are made of aerogel having a three-dimensional mesh structure with a skeleton composed of clusters which are aggregates of primary particles, the insulating fine particles have a three-dimensional mesh structure with a skeleton composed of the primary particles, and 50% or more of the volume of the insulating fine particles are dispersed with a mode of particle diameter of 0.1 μm or more and 1.0 μm or less,
    The matrix fibers include a thermoplastic resin.
    Insulating fiber.
  21. 　請求項１９に記載される断熱繊維の製造方法であって、
    　前記断熱性微粒子を分散させて断熱性微粒子含有懸濁液を調製する工程と、
    　結合剤を溶かして結合剤溶液を調製する工程と、
    　前記断熱性微粒子含有懸濁液と前記結合剤溶液とを混ぜてスラリーを調製する工程と、
    　前記母材繊維に対して、前記スラリーを蒸発源として蒸着する工程とを含む、
    　断熱繊維の製造方法。     20. A method for producing the insulating fiber according to claim 19, comprising the steps of:
    A step of dispersing the heat insulating fine particles to prepare a heat insulating fine particle-containing suspension;
    Dissolving a binder to prepare a binder solution;
    A step of mixing the heat insulating fine particle-containing suspension and the binder solution to prepare a slurry;
    The method includes a step of depositing the slurry as an evaporation source onto the base fiber.
    A method for producing insulating fibers.
  22. 　請求項１９に記載される断熱繊維の製造方法であって、
    　結合剤を溶かして結合剤溶液を調製する工程と、
    　母材繊維に対して、前記結合剤溶液を蒸発源として蒸着する工程と、
    　前記蒸着によって結合剤溶液が表面に付着した前記母材繊維に、断熱性微粒子を機械的に塗す工程と、を含む、
    　断熱繊維の製造方法。     20. A method for producing the insulating fiber according to claim 19, comprising the steps of:
    Dissolving a binder to prepare a binder solution;
    depositing the binder solution onto the base fiber as an evaporation source;
    and mechanically applying heat insulating fine particles to the base material fibers having the binder solution attached to the surface thereof by the vapor deposition.
    A method for producing insulating fibers.
  23. 　請求項２１において、
    　前記蒸着する工程で行われる蒸着は、超音波蒸着または加熱蒸着である、
    　断熱繊維の製造方法。     22. In claim 21,
    The deposition performed in the deposition step is ultrasonic deposition or thermal deposition;
    A method for producing insulating fibers.
  24. 　請求項２１において、
    　前記断熱性微粒子が疎水性であって、前記断熱性微粒子含有懸濁液は、アルコールを含む、
    　断熱繊維の製造方法。
     
     
     

     
          22. In claim 21,
    The heat insulating fine particles are hydrophobic, and the heat insulating fine particle-containing suspension contains alcohol.
    A method for producing insulating fibers.
PCT/JP2024/002618 2023-01-31 2024-01-29 Insulation sheet and method for manufacturing same, insulation fibers and method for manufacturing same, and fiber-containing suspension used to manufacture insulating sheet WO2024162246A1 (en)

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