JP2017057541A - Foamable sheet-formed material, foam, method for producing foamable sheet-formed material, and method for producing foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foamable sheet-formed material which can achieve both weight saving and high strength, and a foam.SOLUTION: A foamable sheet-formed material comprises thermosetting resin, a short fiber, and a thermally expandable microcapsule.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foamable paper product, a foam, a method for producing a foamable paper product, and a method for producing a foam.

  In Patent Document 1, a thermoplastic resin, a thermally expandable microcapsule, a fiber reinforced resin composition containing a reinforcing fiber is used, and a foaming method is performed by foaming with a thermally expandable microcapsule using a molding method such as injection molding. It is disclosed to produce a shaped body.

In addition, “papermaking” is generally used as a technical term indicating the state of an object obtained by using a method of spreading a fiber material. This state is described in Patent Documents 2 and 3, for example. According to the document, the papermaking product is described as a wet solid content remaining on a filter after a liquid component is dehydrated from a raw material slurry in which raw materials such as fibers and resins are dispersed in a dispersion medium. ing. The said wet state here means the hardening state before performing drying and heat processing, ie, the hardening state before post-cure.
Moreover, according to the same literature, the said papermaking body is utilized for the molded object obtained by heating and drying-molding in a shaping | molding die. That is, it is described that the papermaking body is used as a molding material.

JP 2010-53351 A Japanese Patent No. 4675276 Patent No. 5426399

However, in the technique described in Patent Document 1, the thermally expandable microcapsule is broken when it is kneaded with the thermoplastic resin and the reinforcing fiber or when it is press-fitted from the injection cylinder into the mold as a foam material. There was. In addition, since the thermoplastic resin and the reinforcing fiber are difficult to mix, there is a problem that uniform and uniform foaming is difficult to obtain, and the amount of the reinforcing fiber is limited.
In addition, if an attempt is made to add a reinforcing material such as reinforcing fiber to the resin in order to simply increase the strength of the foam, the foam tends to be difficult to foam.
As described above, in the foam, there is a trade-off relationship between realizing weight reduction and increasing the strength, and thus it is difficult to achieve both at a high level.

  The present invention has been made in view of the above circumstances, and relates to a foamable papermaking product that achieves both weight reduction and high strength, and a foamed product.

  As a result of the present inventors diligently studying the above problems, by using a foamable paper-making body in which a thermosetting resin, a short fiber, and a thermally expandable microcapsule are used, the thermally expandable microcapsule is kneaded or injection molded. The heat-expandable microcapsules, the thermosetting resin, and the short fibers are uniformly mixed while being entangled with each other, and the content of the short fibers is not broken by the press-fitting of The knowledge that can be increased. Then, by forming a foam using the foamable papermaking product, it was found that uniform and uniform foaming was obtained, weight reduction was achieved, and high strength was obtained, and the present invention was completed.

  The present invention provides a foamable papermaking product comprising a thermosetting resin, short fibers, and thermally expandable microcapsules.

  The present invention provides a foam in which the foamable paper product is foamed.

The present invention also provides a foam comprising a thermosetting resin, short fibers, and foamed particles of a plurality of thermally expandable microcapsules, and having a specific gravity of 1.6 g / cm ³ or less.

  Moreover, this invention provides the manufacturing method of a foamable papermaking body including the process of mixing a thermosetting resin, a short fiber, and a thermally expansible microcapsule, and then making papermaking and obtaining a foamable papermaking body.

  The present invention also includes a step of mixing a thermosetting resin, short fibers, and thermally expandable microcapsules, and then making a paper to obtain a foamable paper, and placing the foamable paper in a mold, And expanding the thermally expandable microcapsule to obtain a foam having a predetermined shape.

  ADVANTAGE OF THE INVENTION According to this invention, the foamable papermaking body excellent in the balance of weight reduction and high intensity | strength, and a foam can be provided.

It is a perspective schematic diagram which shows an example of the foamable papermaking concerning 1st Embodiment. It is a cross-sectional schematic diagram which shows an example of the manufacturing method of the foamable papermaking concerning 1st Embodiment. It is a cross-sectional schematic diagram which shows an example of the manufacturing method of the foam which concerns on 1st Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

[First Embodiment]
<Foaming papermaking>
The foamable papermaking product according to this embodiment is obtained by a papermaking method described later, and has structural features A to C in the following points.
(Feature A) The short fibers are randomly oriented in the plan view of the surface of the foamable paper product.
(Feature B) In the cross-sectional view in the thickness direction of the foamable papermaking product, the orientation state of the short fibers is highly controlled, and the short fibers are oriented in a specific direction. In other words, the short fibers are in a laminated state in the thickness direction of the foamable papermaking product.
(Feature C) Short fibers are bound together by a thermosetting resin.

Further, the foamable papermaking material is a material for obtaining a foamed body by molding into a desired shape by foaming treatment.
The resin in the foamable paper product is not completely cured, for example, in a B stage state. Therefore, the foamable papermaking product can be transformed into another shape. The foamable paper product can be heated at the curing temperature of the resin used to foam the resin completely and obtain a foam.

(Thermosetting resin)
The thermosetting resin functions as a binder. Examples of the thermosetting resin include phenol resin, epoxy resin, unsaturated polyester resin, melamine resin, and polyurethane. These resins can be appropriately selected and used as necessary, and one kind may be used alone, or two or more kinds may be used in combination.
From the viewpoint of mechanical properties, it is more preferable to include at least one of a phenol resin and an epoxy resin, and from the viewpoint of achieving both weight reduction and high strength, a phenol resin is more preferable.

  The thermosetting resin may have a granular or powdery shape. Thereby, the intensity | strength of the foam obtained by foaming and hardening a foamable papermaking body can be improved more effectively. The reason for this is not clear, but when the foamable paper product is heated and pressurized to be foamed, the thermosetting resin has a granular or powdery shape, so that the impregnation property at the time of melting is improved, and short fibers, It is estimated that the interface with the thermosetting resin is well formed.

As the thermosetting resin, for example, a solid-state resin having an average particle diameter of 500 μm or less can be used. Thereby, in the manufacturing process of the foamable papermaking body mentioned later, it can make it easier to form the aggregation state of a thermosetting resin. Moreover, in the manufacturing process of a foamable papermaking body, from the viewpoint of obtaining a varnish-like material composition, the average particle size of the thermosetting resin is more preferably 1 nm or more and 300 μm or less.
The thermosetting resin having such an average particle diameter can be obtained by performing a pulverization process using, for example, an atomizer pulverizer.
The average particle size of the thermosetting resin is determined, for example, by using a laser diffraction particle size distribution measuring device such as SALD-7000 manufactured by Shimadzu Corporation as the average particle size based on a 50% particle size. Can do.

  The thermosetting resin contained in the foamable paper product is preferably in a semi-cured state. The semi-cured thermosetting resin is completely cured in the step of producing a foamable paper product, foaming it into a desired shape by heating and pressing, and molding it. Thereby, the foam excellent in the balance of high intensity | strength and weight reduction is obtained.

(Short fiber)
The short fiber is obtained by cutting a fiber yarn or a long fiber bundle into a predetermined length.
The average fiber length of the short fibers is preferably 0.1 mm or more from the viewpoint of obtaining a special structure by papermaking, more preferably 2 mm or more, and 2.5 mm or more from the viewpoint of obtaining mechanical strength. More preferably, it is more preferably 4 mm or more. On the other hand, from the viewpoint of obtaining good dispersibility, it is preferably 20 mm or less, more preferably 15 mm or less, and further preferably 12 mm or less.

  Examples of the short fibers include inorganic fibers such as metal fibers, ceramic fibers, glass fibers, and carbon fibers, wholly aromatic polyamides (aramids), wholly aromatic polyesters, wholly aromatic polyester amides, wholly aromatic polyethers, wholly aromatics. Polycarbonate, wholly aromatic polyazomethine, polyphenylene sulfide (PPS), poly (para-phenylenebenzobisthiazole) (PBZT), polybenzimidazole (PBI), polyetheretherketone (PEEK), polyamideimide (PAI), polyimide Organic fibers such as polytetrafluoroethylene (PTFE) and poly (para-phenylene-2,6-benzobisoxazole) (PBO). These short fibers can be appropriately selected and used as necessary, and one kind may be used alone, or two or more kinds may be used in combination.

  Furthermore, from the viewpoint of achieving a balance between weight reduction and strength, inorganic fibers are preferable, glass fibers and carbon fibers are more preferable, and carbon fibers are more preferable. Moreover, when glass fiber is used, the thing which processed aminosilane is preferable. The aminosilane treatment is performed by impregnating glass fibers with an amino group-containing silane coupling agent solution, or by applying an amino group-containing silane coupling agent solution to glass fibers.

  Examples of amino group-containing silane coupling agents include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyl. Methyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β An amino group-containing alkoxysilane such as (aminoethyl) -γ-aminopropylmethyldiethoxysilane, and hydrolysates thereof. These amino group-containing silane coupling agents may be used alone or in combination of two or more.

  The content of the short fiber is preferably 10% by weight or more, more preferably 20% by weight or more with respect to the thermosetting resin, from the viewpoint of increasing the strength. From the viewpoint of balancing the strength and weight reduction, it is preferably 80% by weight or less, more preferably 75% by weight or less, and still more preferably 70% by weight or less with respect to the thermosetting resin. 50% by weight or less is particularly preferable.

(Thermal expansion microcapsule)
Thermally expandable microcapsules are particles obtained by microencapsulating a volatile liquid foaming agent with a thermoplastic shell polymer having gas barrier properties. Thermally expandable microcapsules are softened in the outer shell of the capsule by heating, but the liquid foaming agent contained in the capsule is vaporized and the pressure is increased. As a result, the particles expand and hollow spherical particles (foamed thermally expandable microcapsules) By forming (particles), it functions as a foaming agent.

Examples of the liquid blowing agent include low boiling point hydrocarbons such as isopentane, isobutane, and isopropane.
Examples of the thermoplastic shell polymer include polyacrylonitrile, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-methyl methacrylate copolymer, vinylidene chloride-ethyl methacrylate, acrylonitrile-methyl methacrylate copolymer, acrylonitrile-ethyl methacrylate, and the like. It is done.

  As the heat-expandable microcapsules, commercially available products such as EXPANSEL (manufactured by Nippon Philite), Microsphere F50, Microsphere F60 (manufactured by Matsumoto Yushi Seiyaku), Advancel EM (manufactured by Sekisui Chemical Co., Ltd.) are used. be able to.

  The content of the heat-expandable microcapsules is preferably 0.05% by weight or more and 0.1% by weight or more with respect to the thermosetting resin from the viewpoint of lowering the specific gravity of the foam. More preferred. Further, from the viewpoint of expressing an appropriate strength of the foam, it is preferably 10% by weight or less, and more preferably 5% by weight or less with respect to the thermosetting resin.

  In addition, the foamable papermaking product in the present embodiment can contain components such as pulp, flocculant, and various additives in addition to the above components.

(pulp)
The foamable papermaking product in the present embodiment may include pulp. Pulp is a fiber material having a fibril structure and is different from the above short fibers. Pulp can be obtained, for example, by mechanically or chemically fibrillating the fiber material.
More stable foamable papermaking can be achieved by making pulp together with thermosetting resin, short fibers, and heat-expandable microcapsules during the production of foamable papermaking. The production of the body can be realized.

  Examples of pulp include cellulose fibers such as linter pulp and wood pulp, natural fibers such as kenaf, jute and bamboo, para-type wholly aromatic polyamide fibers (aramid fibers) and copolymers thereof, aromatic polyester fibers, and polybenza. Examples include fibrillated organic fibers such as sol fibers, meta-type aramid fibers and copolymers thereof, acrylic fibers, acrylonitrile fibers, polyimide fibers, and polyamide fibers. Pulp may be used individually by 1 type and may use 2 or more types together.

  The pulp content is preferably 0.5% by weight or more, more preferably 1% by weight or more, and still more preferably 2% by weight or more based on the thermosetting resin. Thereby, aggregation of the thermosetting resin at the time of papermaking can be generated more effectively, and a more stable production of foamable papermaking can be realized. On the other hand, the pulp content is preferably 10% by weight or less, more preferably 8% by weight or less, and still more preferably 5% by weight or less with respect to the thermosetting resin. Thereby, it becomes possible to improve the mechanical characteristic and thermal characteristic of a foam more effectively.

(Flocculant)
The foamable papermaking product in this embodiment may contain a flocculant. The aggregating agent has a function of aggregating the thermosetting resin, the short fibers, and the thermally expandable microcapsules in a flock state during the production of the foamable papermaking product. For this reason, the production of a more stable foamable papermaking product can be realized.

  Examples of the flocculant include a cationic polymer flocculant, an anionic polymer flocculant, a nonionic polymer flocculant, and an amphoteric polymer flocculant. More specifically, for example, cationic polyacrylamide, anionic polyacrylamide, Hoffman polyacrylamide, mannic polyacrylamide, amphoteric copolymerized polyacrylamide, cationized starch, amphoteric starch, polyethylene oxide and the like can be mentioned. These flocculants may be used individually by 1 type, and may use 2 or more types together. In the flocculant, the polymer structure and molecular weight, the amount of functional groups such as hydroxyl groups and ionic groups, and the like can be adjusted according to the required characteristics.

  The content of the flocculant is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and more preferably 0.1% by weight or more based on the thermosetting resin. Further preferred. Thereby, the improvement of a yield can be aimed at in manufacture of an expandable papermaking body. On the other hand, the content of the flocculant is preferably 1.5% by weight or less, more preferably 1% by weight or less, and preferably 0.5% by weight or less with respect to the thermosetting resin. Further preferred. This makes it possible to perform dehydration and the like more easily and stably in the production of foamable papermaking using a papermaking method.

  The foamable paper product of the present embodiment can further use various additives for the purpose of adjusting production conditions and expressing required physical properties. For example, thermoplastic resins, inorganic powders for improving properties, metal powders, stabilizers such as antioxidants and UV absorbers, flame retardants, mold release agents, plasticizers, resin curing catalysts and accelerators, pigments , Dry paper strength improver, wet strength strength improver, yield improver, drainage improver, size fixer, rosin sizing agent for acidic papermaking, rosin sizing agent for neutral papermaking, alkyl Examples thereof include sizing agents such as ketene dimer sizing agents, alkenyl succinic anhydride sizing agents and specially modified rosin sizing agents, and coagulants such as sulfuric acid bands, aluminum chloride and polyaluminum chloride.

<Method for producing foamed paper>
In the present embodiment, the method for producing a foamable paper product includes a step of mixing a thermosetting resin, short fibers, and thermally expandable microcapsules, and then papermaking to obtain a foamable paper product. The obtained foamed papermaking material becomes a raw material of the foam described later.

The papermaking method indicates a papermaking technique which is one of papermaking techniques.
The foamable paper product of the present embodiment is obtained by treating a material composition containing a thermosetting resin, short fibers, and thermally expandable microcapsules by a papermaking method, whereby the surface direction of the foamable paper product (XY axis direction). ), It is considered that random entanglement can be appropriately made while maintaining the shape of the short fiber, and a special structure in which these overlap in the thickness direction (Z-axis direction) can be formed.
As a result, it becomes possible to mix a large amount of short fibers into the thermosetting resin, and it is possible to obtain a foamable paper product having an excellent balance between weight reduction and strength.

FIG. 1 is a schematic perspective view showing an example of a foamable papermaking product according to this embodiment.
As shown in FIG. 1, in the foamable papermaking product 10, the thermosetting resin (A), the short fibers (B), and the thermally expandable microcapsules (C) are entangled randomly in the plane direction. It has a special structure by papermaking so that the smooth surfaces overlap in the thickness direction. The short fibers (B) are bound to each other by the thermosetting resin (A). The short fiber (B) may have a linear shape in a plan view, may be curved, or may be bent.

  FIG. 2 is a schematic cross-sectional view showing an example of a method for producing an expandable paper product according to this embodiment. Hereinafter, with reference to FIG. 2, the manufacturing method of the foamable papermaking body 10 by a wet papermaking method is explained in full detail.

First, as shown to Fig.2 (a), a thermosetting resin (A), a short fiber (B), and a thermally expansible microcapsule (C) are added to a solvent, and it stirs, mixes, and disperses. Thereby, the varnish-like material composition for forming a foamable papermaking body can be obtained.
Under the present circumstances, you may add other components except a flocculent among the components mentioned above in a solvent.

  A method of dispersing each component in a solvent is not particularly limited, and examples thereof include a method of stirring using a disperser.

The solvent is not particularly limited, but it is difficult to volatilize in the process of dispersing the constituent materials of the material composition, and it is easy to remove the solvent in order to suppress the remaining in the foamed paper product. From the standpoint of suppressing the increase in energy, those having a boiling point of 50 ° C. or higher and 200 ° C. or lower are preferable.
Examples of such a solvent include alcohols such as water, ethanol, 1-propanol, 1-butanol, and ethylene glycol; ketones such as acetone, methyl ethyl ketone, 2-heptanone, and cyclohexanone; ethyl acetate, butyl acetate, and acetoacetic acid. Examples thereof include esters such as methyl and methyl acetoacetate, and ethers such as tetrahydrofuran, isopropyl ether, dioxane and furfural. These solvents may be used alone or in combination of two or more. Among these, it is more preferable to use water because the supply amount is abundant, the cost is low, the environmental load is low, the safety is high, and the handling is easy.

  In the present embodiment, a flocculant can be further added to the varnish-like material composition obtained above. Thereby, it is easier to obtain the aggregate (F) by aggregating the thermosetting resin (A), the short fiber (B), and the thermally expandable microcapsule (C) in a solvent in a floc form. (See FIG. 2B).

Next, as shown in FIG. 2 (b), the solvent and the aggregate (F) obtained above are put into a container whose bottom surface is composed of a sheet-like mesh 30, and the solvent is removed from the mesh 30. Discharge. Thereby, the aggregate (F) and the solvent can be separated from each other. As a result, the aggregate (F) remains on the mesh 30.
Here, by appropriately selecting the shape of the mesh 30, it is possible to adjust the shape of the foamable paper product to be obtained.

  In the present embodiment, the agglomerate (F) obtained above can be taken out, placed in a drying furnace and dried to further remove the solvent. Thus, the foamable papermaking body 10 as shown in FIG.2 (c) is manufactured.

<Foam>
In the present embodiment, the foam is in a state where the foamable paper product is foamed. In addition, the foam includes a thermosetting resin, short fibers, and foamed particles of a plurality of thermally expandable microcapsules, and has a specific gravity of 1.6 g / cm ³ or less.
The expanded particles of the thermally expandable microcapsule are spherical hollow particles in which a thermally expandable microcapsule described later is expanded.
The specific gravity of the foam is 1.6 g / cm ³ or less, and preferably 1.5 g / cm ³ or less from the viewpoint of weight reduction.

<Method for producing foam>
In this embodiment, the method for producing a foam includes a step of mixing a thermosetting resin, short fibers, and thermally expandable microcapsules, and then making a paper to obtain a foamable paper, and the foamable paper And expanding the thermally expandable microcapsule to obtain a foam having a predetermined shape.

  FIG. 3 is a schematic cross-sectional view showing an example of a method for producing a foam according to the present embodiment. Hereinafter, with reference to FIG. 3, the manufacturing method of the foam 50 is explained in full detail.

As shown in FIG. 3A, the foamable papermaking body 10 is disposed in the mold 40 and the mold 41. At this time, the volume of the mold cavity including the mold 40 and the mold 41 is assumed to be larger than the volume of the foamable papermaking product 10. That is, the foam of this embodiment can be manufactured using a so-called short shot method.
Next, the heat-expandable microcapsule (C) is expanded by heating and pressurizing to foam the foamable papermaking product 10, and the foam 50 is filled into the mold cavity. Thereby, the foam 50 which has a bubble (D) (expanded particle of a thermally expansible microcapsule) as shown in FIG.3 (b) is obtained. That is, the thermally expandable microcapsule (C) contained in the foamable papermaking product 10 is expanded by heat treatment to form bubbles (D). As a result, the entire foamable papermaking body 10 is enlarged, and the foam 50 is filled in the mold cavity, and the foam 50 is shaped into a predetermined shape by utilizing the foaming pressure by the thermally expandable microcapsule (C). To mold.

  As the heat and pressure treatment, for example, the foam 50 can be molded into a predetermined shape at 160 to 250 ° C. and 1.5 to 5 MPa for 10 to 30 minutes.

  Thereby, the problem that the thermally expandable microcapsule (C) cannot be foamed and the problem that the bubbles (D) are crushed by the filling pressure and holding pressure by the conventional injection molding method can be reduced.

  Moreover, according to this invention, destruction of the thermally expansible microcapsule by kneading | mixing can be suppressed by using the foamable papermaking body which combined the thermosetting resin, the short fiber, and the thermally expansible microcapsule. Further, according to the present invention, the structure of the expandable paper-making body in which the thermally expandable microcapsules, the thermosetting resin, and the short fibers are entangled with each other, the content of the short fibers can be increased, By combining a thermosetting resin, short fibers, and thermally expandable microcapsules, uniform and uniform good foaming can be obtained. As a result, by forming a foam using the foamable paper product, weight reduction is achieved and high strength is obtained.

[Second Embodiment]
Subsequently, a second embodiment of the present invention will be described. Here, it demonstrates centering around difference with embodiment mentioned above, The description of the same matter is abbreviate | omitted.

The foamable papermaking product according to the present embodiment is characterized by containing metal fibers as short fibers, and can thereby impart electromagnetic wave shielding properties as a foam.
Here, in this embodiment, since the foam is formed from the foamable papermaking product, the weight of the foam can be reduced, and both the high electromagnetic shielding properties and the light weight can be satisfied. it can.

The metal fiber that can be used here may be a metal fiber composed of a single metal element or an alloy fiber composed of a plurality of metals, and may also be a metal-coated organic fiber or metal-coated fiber. You may use the fiber which coat | covered the other member with the metal like carbon fiber.
Examples of the metal element constituting such a metal fiber include iron, silver, nickel, aluminum, copper, and the like.

Examples of commercially available and easily available metal fibers include stainless steel fiber manufactured by Nippon Seisen Co., Ltd. and Bekaert Japan Co., Ltd., copper fiber manufactured by Niji Co., Ltd., aluminum fiber, brass fiber, steel fiber, titanium fiber, phosphor bronze fiber, etc. However, it is not limited to these.
Of these, stainless steel fiber is particularly preferred because of its high relative permeability.

  In addition, these metal fibers may be used as they are, but they may be surface-treated with a silane coupling agent, an aluminate coupling agent, a titanate coupling agent, etc. depending on the required properties, or may have adhesiveness and handleability with a resin. In order to improve the above, a product treated with a sizing agent may be used.

  In the present embodiment, the content of the metal fiber is preferably 1% by weight or more, and more preferably 2% by weight or more with respect to the thermosetting resin, from the viewpoint of increasing the electromagnetic shielding. From the viewpoint of achieving a balance between strength and weight reduction, the content is preferably 50% by weight or less, and more preferably 40% by weight or less with respect to the thermosetting resin.

  In addition, the foamable papermaking body which concerns on this embodiment may use together the short fiber comprised with another member other than said metal fiber. The short fibers that can be used are as shown in the first embodiment.

In the present embodiment, the specific gravity of the foam in the state in which the foamable papermaking body is foamed is preferably 1.6 g / cm ³ or less as in the first embodiment. It is more preferably 5 g / cm ³ or less, further preferably 1.35 g / cm ³ or less, and particularly preferably 1.3 g / cm ³ or less.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  EXAMPLES Next, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.

[Examples 1 to 4, Comparative Example 1]
The materials used in the examples and comparative examples are as follows.
-Phenol resin: Phenol resin "PR51723" manufactured by Sumitomo Bakelite Co., Ltd.-Carbon fiber-1: PAN-based carbon fiber "Tenax (registered trademark) HT C110": manufactured by Toho Tenax Co., Ltd .: average fiber length 6 mm
Carbon fiber-2: PAN-based carbon fiber “Tenax (registered trademark) HT C110”: manufactured by Toho Tenax Co., Ltd .: average fiber length 3 mm
Glass fiber-1: chopped strand “CS3J 891”: manufactured by Nittobo Co., Ltd. Glass fiber-2: obtained by impregnating glass fiber-1 with a solution of an amino group-containing silane coupling agent (aminosilane) It was used.
-Thermally expandable microcapsule: “Advancel (registered trademark) EM304” manufactured by Sekisui Chemical Co., Ltd.

(Manufacture of foamable paper products)
With the formulation (parts by weight) shown in Table 1, foamable paper products were produced as follows.
First, a thermosetting resin, short fibers, and thermally expandable microcapsules pulverized to an average particle size of 100 μm (50% particle size based on mass) with an atomizer pulverizer are added to water, and 30 minutes with a disperser. Stir to give a mixture. Here, a total of 100 parts by weight of a constituent material composed of a thermosetting resin and short fibers was added to 10,000 parts by weight of water.
Next, a flocculant previously dissolved in water was added in an amount of 0.2% by weight based on the total of the constituent materials described above, and the constituent materials were aggregated in a floc form.
Subsequently, the obtained agglomerate is separated from water with a 30-mesh metal net, and then the agglomerate is subjected to dehydration pressing, and further dried in a drier at 70 ° C. for 3 hours to obtain a foamable paper product. Got. The yield was 97%.

(Manufacture of foam)
The obtained foamable papermaking product was placed in a 4 mm thick mold and subjected to heat and pressure treatment at 180 ° C. and 2 MPa for 10 minutes to produce a foamed product.
Each evaluation was performed about the obtained foam. The results are shown in Table 1.

(Evaluation)
Density: measured by a method based on JIS K-7112 A method.

-Bending strength: It measured by the method based on JISK-7171.

[Examples 5 to 6, Comparative Example 2]
The materials used in the examples and comparative examples are as follows.
・ Phenolic resin: phenolic resin “PR51723” manufactured by Sumitomo Bakelite Co., Ltd. ・ Metal fiber: Stainless steel fiber “Naslon (registered trademark) CHOP6 / 5CMC”: manufactured by Nippon Seisen Co., Ltd .: average fiber length 5 mm
Aramid fiber: Aramid fiber “Technola (registered trademark) P32TNW”: manufactured by Teijin Limited: average fiber length of 3 mm
Thermally expandable microcapsule: “Advancel (registered trademark) EM304” manufactured by Sekisui Chemical Co., Ltd.

(Manufacture of foamable paper products)
With the formulation (parts by weight) shown in Table 2, foamable paper products were produced as follows.
First, a thermosetting resin, short fibers, and thermally expandable microcapsules pulverized to an average particle size of 100 μm (50% particle size based on mass) with an atomizer pulverizer are added to water, and 30 minutes with a disperser. Stir to give a mixture. Here, a total of 100 parts by weight of a constituent material composed of a thermosetting resin and short fibers was added to 10,000 parts by weight of water.
Next, a flocculant previously dissolved in water was added in an amount of 0.2% by weight based on the total of the constituent materials described above, and the constituent materials were aggregated in a floc form.
Subsequently, the obtained agglomerate is separated from water with a 30-mesh metal net, and then the agglomerate is subjected to dehydration pressing, and further dried in a drier at 70 ° C. for 3 hours to obtain a foamable paper product. Got. The yield was 97%.

(Manufacture of foam)
The obtained foamable papermaking product was placed in a 4 mm thick mold and subjected to heat and pressure treatment at 180 ° C. and 2 MPa for 10 minutes to produce a foamed product.
Each evaluation was performed about the obtained foam. The results are shown in Table 2.

(Evaluation)
Density: measured by a method based on JIS K-7112 A method.

Flexural strength and flexural modulus: measured by a method based on JIS K-7171.

Specific strength and specific elastic modulus: Calculated by dividing the obtained bending strength and bending elastic modulus by density.

-EMI shielding characteristics: In the range of 0.5 MHz to 500 MHz, evaluation was performed with ◯ indicating a shielding effect of 99% or more (KEC method, electric field), and × indicating that the shielding effect was less than that.

  As is apparent from Table 2, in Examples 5 and 6, the weight reduction as a molded body was achieved while having the same electromagnetic shielding properties (EMI shielding properties) as compared with Comparative Example 2.

DESCRIPTION OF SYMBOLS 10 Foamable body 30 Mesh 40 Mold 41 Mold 50 Foam A Thermosetting resin B Short fiber C Thermally expansible microcapsule D Bubble F Flocculant

Claims (10)

  A foamable papermaking product comprising a thermosetting resin, short fibers, and thermally expandable microcapsules. In the foamable papermaking according to claim 1,
A foamable papermaking product, wherein the short fibers contain carbon fibers. In the foamable papermaking according to claim 1,
A foamable papermaking product, wherein the short fibers include metal fibers. In the foamable papermaking according to any one of claims 1 to 3,
The foamable papermaking product, wherein the content of the short fibers is 10 to 70% by weight with respect to the thermosetting resin. In the foamable papermaking product according to any one of claims 1 to 4,
The foamable papermaking product, wherein the thermosetting resin is a phenol resin.   The foam in which the foamable papermaking body as described in any one of Claims 1 thru | or 5 foamed. A foam comprising a thermosetting resin, short fibers, and expanded particles of a plurality of thermally expandable microcapsules and having a specific gravity of 1.6 g / cm ³ or less. The foam according to claim 7,
The foamed body whose content of the said short fiber is 10 to 70 weight% with respect to the said thermosetting resin.   A method for producing a foamable paper product comprising a step of mixing a thermosetting resin, a short fiber, and a thermally expandable microcapsule, and then paper making to obtain a foamable paper product. Mixing a thermosetting resin, short fibers, and thermally expandable microcapsules, and then making paper to obtain a foamable paper product;
Disposing the foamable papermaking body in a mold and expanding the thermally expandable microcapsule to obtain a foam having a predetermined shape.

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