JP2011090060A - Sound absorbing material and sound insulating panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight sound absorbing material with an excellent sound absorbing property. <P>SOLUTION: A sound absorbing material 1 includes a porous pulp fiber of more than 90 mass% in a range of 350 to 650 ml (CSF) of a refining degree by a Canadian standard freeness degree which is specified to JIS P 8121-1995-4. Canadian Standard Freeness, and it is composed of a water-repellent laminating fiber sheet 5 which is impregnated with water-repellent, in which an organic synthetic fiber sheet 3 is backed through an air permeability adhesive layer 4, on a pulp fiber sheet 2 with air permeability resistance of 0.08 to 3.00 kPa s/m, and a fiber mat 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sound absorbing material used for a sound insulating wall of an expressway, for example, and a sound insulating wall panel incorporating the sound absorbing material.

  Conventionally, a synthetic fiber mat, a glass fiber mat, rubber, or a soft plastic is used as a sound absorbing material used for this type of sound insulation wall panel.

JP 2002-69940 A Japanese Patent Laid-Open No. 2004-132018 JP 2007-86505 A

However, the conventional sound absorbing material has a weight per unit area of 1000 g / m ² or more, and has a problem that it is heavy and difficult to construct.

According to the present invention, as a means for solving the above-described conventional problems, the beating degree is JIS P 8121-1995 4. It contains 90% by mass or more of a porous pulp fiber in the range of 350 to 650 ml (CSF) with a Canadian standard freeness specified by Canadian Standard Freeness, and a ventilation resistance of 0.08 to 3.00 kPa · s / m. Water-repellent laminated fiber sheets 5, 5A obtained by impregnating a laminated fiber sheet in which a synthetic fiber sheet 3, 3A is lined with a pulp fiber sheet 2, 2A through a breathable adhesive layer 4, 4A and a water-repellent agent. The sound-absorbing material 1, 11, 21, 31 comprising the fiber mats 6, 6A, 6B is provided.
The basis weight of the organic synthetic fiber sheets 3 and 3A is preferably 10 to ²⁰⁰ g / m ² .
Usually, the basis weight of the pulp fiber sheets 2 and 2A is 10 to 50 g / m ² , and the basis weight of the fiber mats 6 and 6A and 6B is 200 to 2000 g / m ² .
Furthermore, the present invention provides the sound insulation wall panels 10 and 20 incorporating the sound absorbing materials 1, 11, 21 and 31.

[Action]
A porous pulp fiber having a large number of pores opened on the surface has air permeability and air retention in the porous pulp fiber itself, and also has a large number of incisions on the fiber surface. Since a sheet made of fibers containing 90% by mass or more of porous pulp fibers having an air permeability is imparted with air permeability and air retention even by a space formed between the fibers, the sound absorbing material has a very large sound absorbing effect.

The ventilation resistance of the pulp fiber sheets 2 and 2A is in the range of 0.08 to 3.00 kPa · s / m. When the ventilation resistance of the pulp fiber sheets 2 and 2A is less than 0.08 kPa · s / m, the density of the pulp fiber sheets 2 and 2A becomes too low, and the strength and rigidity of the pulp fiber sheets 2 and 2A are lowered. On the other hand, if the airflow resistance exceeds 3.00 kPa · s / m, the density of the pulp fiber sheets 2 and 2A becomes high, the sound absorption characteristics become insufficient, and the moldability also deteriorates.
The porous pulp fiber having a large number of pores opened on the surface is a pulp fiber that has been moderately beaten.

  Beating the pulp fiber mechanically or grinding using a beater or disc refiner is called beating. When the pulp fiber is beaten, the fiber surface becomes fluffy due to friction during the beating process, whiskers are generated, and fine air grooves (holes) on the fiber surface are enlarged to make the fiber porous. 3. The beating degree of the pulp fiber is JIS P 8121-1995. If the Canadian standard freeness specified by the Canadian Standard Freeness is below 350 ml (CSF), the beating of the porous pulp fiber will proceed excessively and the fiber will be subdivided. When used, the density of the paper, which is a fiber sheet, is increased and the sound absorption characteristics are lowered. On the other hand, if the pulp fiber has a beating degree of more than 650 ml (CSF), fiber fluffing, flapping or concentric looseness is insufficient, and the pulp fiber is insufficiently porous, resulting in poor air permeability and air retention. As a result, the sound absorption characteristics deteriorate.

Since the pulp fiber sheets 2 and 2A have a very high sound absorbing effect as described above, the sound absorbing materials 1, 11, 21, and 31 in which the water-repellent laminated fiber sheets 5 and 5A are laminated on a fiber mat have the fiber mat 6 , 6A, 6B, a sound-absorbing material having a ventilation resistance in the range of 0.40 to 6.0 kPa · s / m, which is desirable for exhibiting high sound-absorbing performance even when the basis weight of 2000A / 6B is reduced to 2000 g / m ² or less 11, 21, 31 are obtained.
The pulp fiber sheets 2 and 2A are required to have water repellency when used as, for example, a sound insulation wall of a road. In order to impart water repellency to the pulp fiber sheets 2 and 2A, it is only necessary to impregnate a water repellent. However, when only the pulp fiber sheets 2 and 2A are impregnated with the water repellent, deformation such as swelling, shrinkage, distortion, etc. Will occur. Therefore, in the present invention, the above-described pulp fiber sheets 2 and 2A are lined with organic synthetic fiber sheets 3 and 3A to prevent deformation.

〔effect〕
In the present invention, a sound absorbing material having a small thickness, light weight, excellent sound absorbing characteristics, and low cost is provided. When the sound absorbing material is used, for example, in a sound insulation wall panel on an expressway, the construction becomes extremely easy.
Further, when the porous pulp fiber used for the pulp fiber sheets 2 and 2A is made of woody pulp fiber, it does not generate a large amount of carbon dioxide in the production process like an organic synthetic fiber, and has a decay property. Since it can be used as energy (for example, a raw material of bioethanol), it is a material that contributes to energy saving measures and global warming prevention measures.

Explanatory drawing explaining protrusion height h Explanatory drawing explaining the measuring method of ventilation resistance R Sectional view of the sound-absorbing material 1 of the present invention Sectional view of the sound-absorbing material 11 of the present invention Explanatory drawing of the sound insulation wall panel 10 of this invention Explanatory drawing of the sound insulation wall panel 20 of this invention

A sound-absorbing material as one embodiment of the present invention includes a water-repellent laminated fiber sheet obtained by impregnating a laminated fiber sheet with a pulp fiber sheet lined with an organic synthetic fiber sheet with a breathable adhesive layer impregnated with a water repellent, and a fiber mat. It consists of.
Each material is described in detail below.

(Porous pulp fiber)
The porous pulp fiber used in the pulp fiber sheet is made of non-wood plant fibers and / or wood plant fibers, and is usually made of softwood or hardwood chips, and the beating degree is JIS P 8121-1995 4. It is a porous pulp fiber in the range of 350 to 650 ml (CSF) with a Canadian standard freeness specified by Canadian Standard Freeness.
The above beating is usually performed by a conical refiner, a disc refiner, or the like. When the beating degree of the pulp fiber exceeds 650 ml (CSF), the pulp fiber is not sufficiently crushed or concentrically loosened, and the porous structure due to the large number of pores opening on the surface of the pulp fiber becomes insufficient. The porosity is lowered and the sound absorbing performance of the sound absorbing material is adversely affected. On the other hand, if it is less than 350 ml (CSF), the pulp fibers are fibrillated and subdivided, and the number of fine fibers increases. Therefore, the density of the pulp fiber sheet made of such pulp fibers, that is, the paper is increased, and the sound absorbing properties of the sound absorbing material are adversely affected. Is affected.
In the said pulp fiber sheet, you may use the mixed fiber which mixed the said porous pulp fiber and the normal fiber (non-porous pulp fiber). In addition, the mixing ratio in this case should contain 90 mass% or more of porous pulp fibers, desirably 95 mass% or more, and more desirably 100 mass%.

(Normal fiber)
Examples of the normal fibers (nonporous pulp fibers) include, for example, polyester fibers, polyethylene fibers, polypropylene fibers, polyamide fibers, acrylic fibers, urethane fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, and organic synthetic fibers such as acetate fibers, Biodegradable fiber (polylactic acid fiber) made of starch extracted from plants such as corn and sugarcane, natural fiber such as pulp, cotton, palm fiber, hemp fiber, bamboo fiber, kenaf fiber, glass fiber, carbon fiber, ceramic fiber Inorganic fibers such as asbestos fibers, or one type or two or more types of recycled fibers obtained by defibrating scraps of fiber products using these fibers are used. Desirable fibers include recycled polyester fibers regenerated from polyester product waste such as PET bottles.

[Pulp fiber sheet]
In order to form a pulp fiber sheet by sheeting the porous pulp fiber or a mixed fiber of the porous pulp fiber and the normal fiber, a general nonwoven fabric manufacturing method such as a papermaking method or a needle punching method is applied. The
As the pulp fiber sheet, an extensible paper material having a large number of irregularities on the surface may be used. When the stretchable paper material is used, a sound absorbing material having excellent sound absorbing performance and good moldability can be obtained.

Examples of the stretchable paper material include crepe paper having a crimped wrinkle formed on the surface, embossed paper having a large number of protrusions formed on the surface, and crepe embossed paper having a crimped wrinkle and many protrusions formed on the surface. Etc. are exemplified.
The creped paper is obtained by creping a raw material. In the crepe processing, a wet crepe that is compressed in the vertical direction using a press roll or a doctor blade in a wet paper state and brazed, and a sheet There is a dry crepe that is dried with a Yankee dryer or calendar and then compressed in the longitudinal direction using a doctor blade or the like.
In this case, it is desirable that the crepe rate calculated by the following formula is 10 to 50%.
Crepe rate (%) = (A / B) × 100
A: Paper making speed in the paper making process B: Paper winding speed That is, the crepe rate is the ratio at which the paper web is compressed in the longitudinal direction (paper making direction) by creping.
When the crepe rate is less than 10%, the sound absorbing performance of the creped paper is deteriorated and the stretchability is insufficient, and wrinkles are easily generated during molding. On the other hand, when the crepe rate exceeds 50%, Again, wrinkles are likely to occur during molding.

The embossed paper is formed by pressing a roll (embossing roll) or plate (embossing plate) having a large number of irregularities on the surface against the base paper to form a large number of protrusions on the surface of the paper. It is desirable that the thickness is 0.02 to 2.00 mm and the number of protrusions is 20 to 200 / cm ² . When the height of the protrusion is less than 0.02 mm, the sound absorption performance of the embossed paper is deteriorated and the stretchability is insufficient so that wrinkles are easily generated during molding. Even if it exceeds 0.000 mm, wrinkles are likely to occur during molding. On the other hand, when the number of protrusions is less than 20 / cm ² , the sound absorption performance of the embossed paper is deteriorated, the stretchability is insufficient, and wrinkles are easily generated during molding, while the number of protrusions is 200 Even if it exceeds / cm ² , the sound absorbing performance of the embossed paper deteriorates.
The embossed paper 1a (extensible paper material) shown in FIG. 1 has a large number of protrusions 1b on the surface, and the height of the protrusions 1b corresponds to “h” shown in FIG. If crepe paper is used as the base paper, it becomes embossed crepe paper.
As described above, the ventilation resistance of the pulp fiber sheet is in the range of 0.08 to 3.00 kPa · s / m.
The basis weight of the pulp fiber sheet is about 5 to 100 g / m ^{2 for} a normal one, whereas the basis weight of the pulp fiber sheet according to the present invention is desirably 10 to 50 g / m ² . When the basis weight is less than 10 g / m ² , the strength of the pulp fiber sheet is lowered and the pulp fiber sheet is easily torn during molding. On the other hand, when the basis weight exceeds 50 g / m ² , the mass is increased. As a result, the light-absorbing material loses its light weight, and the moldability is lowered and wrinkles are likely to occur.

[Organic synthetic fiber sheet]
As an organic synthetic fiber used for an organic synthetic fiber sheet, the organic synthetic fiber similar to the organic synthetic fiber used as said normal fiber is illustrated, for example.
Moreover, as said organic synthetic fiber, you may use the low melting-point thermoplastic resin fiber whose melting | fusing point is 180 degrees C or less. Examples of the low-melting point thermoplastic resin fiber include polyolefin fibers such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyvinyl chloride fiber, polyurethane fiber, polyester fiber, and polyester copolymer. There are polymer fibers, polyamide fibers, polyamide copolymer fibers and the like. These low melting point thermoplastic resin fibers are used alone or in combination of two or more. Further, these low melting point thermoplastic resin fibers are used as cores and high melting point fibers having a melting point of 200 ° C. or higher are used as sheaths, or high melting point fibers having melting points of 200 ° C. or higher are used as cores, and low melting point thermoplastic resin fibers are used as sheaths. A core-sheath composite fiber or the like is used.
The organic synthetic fiber sheet is a needle punched nonwoven fabric in which the organic synthetic fiber web is entangled by a needle punch, or the organic synthetic fiber web containing the low-melting-point thermoplastic resin fiber or an entangled product by the needle punch. It is provided as a nonwoven fabric or a fiber knitted fabric in which fibers are bound by heating to melt the low melting point thermoplastic resin fibers.
In addition, from the viewpoint of light weight and sound absorbing performance of the sound absorbing material, the basis weight of the organic synthetic fiber sheet is desirably 10 to ²⁰⁰ g / m ² .

[Laminated fiber sheet]
The pulp fiber sheet and the organic synthetic fiber sheet are bonded by a breathable adhesive layer to form a laminated fiber sheet. The breathable adhesive layer can be applied by, for example, distributing hot melt adhesive powder, interposing a web-like hot melt adhesive layer, spraying a solution or aqueous emulsion by spray coating, silk printing, offset printing, etc. It is formed by the method of apply | coating to a shape or a line | wire. When distributing hot melt adhesive powder, from the viewpoint of improving sound absorption performance, the particle size by the sieving method of hot melt adhesive powder is in the range of 80 to 500 μm and the softening temperature is in the range of 80 to 180 ° C. the amount is preferably in the range of 2 to 40 g / ^{m 2.}

[Water repellent laminated fiber sheet]
The laminated fiber sheet is impregnated with a water repellent by a general coating impregnation method such as spray coating, roll coating, knife coating, flow coating, dipping, etc. to obtain a water-repellent laminated fiber sheet.
Examples of the water repellent include paraffin, waxes, metal salts (such as aluminum acetate), metal soaps (such as aluminum soap), zirconium salts of fatty acids, silicon resins, fluorine-based resins, fluorinated fatty acid amides, chromium complex salts (stearyl) Chromic chloride, etc.), octadecyloxymethylpyridinium chloride, stearamide methylpyridinium chloride, octadecylethyleneurea, alkyl ketene dimer, polyfluorocarbon compound and the like, emulsion, or dispersion. Two or more water repellents may be used in combination.
In the laminated fiber sheet, since the organic fiber sheet is lined with the pulp fiber sheet, deformation such as swelling, shrinkage, and distortion does not occur when the water repellent is impregnated.
In addition, the water repellent laminated fiber sheet impregnated with the water repellent agent desirably has a ventilation resistance of 0.10 to 4.00 kPa · s / m from the viewpoint of improving sound absorption performance.

Here, the ventilation resistance (Pa · s / m) is a scale representing the degree of ventilation of the breathable material. This ventilation resistance is measured by a steady flow differential pressure measurement method. As shown in FIG. 2, the test piece T is arranged in the cylindrical air passage W, and the pressure in the air passage W on the starting point side of the arrow in the figure in a state of a constant air flow V (the direction of the arrow in the figure). By measuring the pressure difference between P1 and the end point P2 of the arrow in the figure, the ventilation resistance R can be obtained from the following equation.
R = ΔP / V
Here, ΔP (= P1−P2): Pressure difference (Pa), V: Air flow rate per unit area (m ³ / m ² · s).
The ventilation resistance can be measured by, for example, an air permeability tester (product name: KES-F8-AP1, manufactured by Kato Tech Co., Ltd., steady flow differential pressure measurement method).

[Fiber mat]
The fiber used as the fiber mat is the same fiber as the normal fiber of the fiber sheet, but the melting point of 180 ° C. is the same as that used for the organic synthetic fiber sheet as all or part of the fiber. The following low melting point thermoplastic fibers can be used.
Examples of the low-melting thermoplastic fibers include polyolefin fibers such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer having a melting point of 180 ° C. or less, polyvinyl chloride fibers, polyurethane fibers, and polyester fibers. Polyester copolymer fibers, polyamide fibers, polyamide copolymer fibers, and the like. These low melting point thermoplastic fibers are used alone or in combination of two or more. The fineness of the low melting point thermoplastic fiber is preferably in the range of 0.1 to 60 dtex. As a desirable low melting point thermoplastic fiber used in the present invention, for example, a core having the above-mentioned normal fiber as a core part and a low melting point thermoplastic resin having a melting point of 100 to 180 ° C. which is a material resin of the low melting point thermoplastic fiber as a sheath. There is a sheath type composite fiber. When the core-sheath type composite fiber is used, the rigidity and heat resistance of the obtained fiber sheet are not lowered.

  The fiber mat is formed by a method in which the fiber web mat is entangled by needle punching or a spunbond method, or the fiber web mat is made of the low-melting thermoplastic fiber, or the low-melting thermoplastic fiber is In the case of being mixed, a thermal bond method in which the low-melting thermoplastic fiber is softened by heating the fiber web mat, or the fiber web mat is impregnated with a synthetic resin binder or A chemical bond method in which the fibers are mixed and bonded, or a stitch bond in which the low-melting thermoplastic fiber is heated and softened after being entangled with the web web mat by needle punching, or stitched with a thread. Method, spun lace method entangled with high-pressure water flow, mat with the above needle punching How to sintering wearing impregnated with the synthetic resin binder is further produced by a method in which woven knitted the fibers.

The basis weight and thickness of the fiber mat according to the present invention can be arbitrarily set in principle, but from the viewpoint of achieving good sound absorption performance, light weight, and thin layer, desirably, the basis weight is 200 to 2000 g / m ² . More desirably, it can be set to 300 to 1000 g / m ² , a thickness of 10 to 150 mm, and more desirably 20 to 100 mm.

<Synthetic resin>
The water-repellent laminated fiber sheet or fiber mat according to the present invention may be coated and / or impregnated and / or mixed with a synthetic resin or the like in order to impart rigidity or moldability or to adjust air permeability. Good. Examples of the synthetic resin include a thermoplastic resin and / or a thermosetting resin.

  Examples of the thermoplastic resin include acrylic acid ester resin, methacrylic acid ester resin, ionomer resin, ethylene-ethyl acrylate (EEA) resin, acrylonitrile / styrene / acrylic rubber copolymer (ASA) resin, and acrylonitrile / styrene copolymer ( AS) resin, acrylonitrile / chlorinated polyethylene / styrene copolymer (ACS) resin, ethylene vinyl acetate copolymer (EVA) resin, ethylene vinyl alcohol copolymer (EVOH) resin, methacrylic resin (PMMA), polybutadiene (BDR), polystyrene (PS), polyethylene (PE), acrylonitrile-butadiene-styrene copolymer (ABS) resin, chlorinated polyethylene (CPE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polypropylene PP), cellulose acetate (CA) resin, syndiotactic polystyrene (SPS), polyoxymethylene (= polyacetal) (POM), polyamide (PA), polyimide (PI), polyamideimide (PAI), poly Etherimide (PEI), polyarylate (PAR), thermoplastic polyurethane (TPU) elastomer, thermoplastic elastomer (TPE), liquid crystal polymer (LCP), polyetheretherketone (PEEK), polysulfone (PSF), polyethersulfone (PES), fluororesin, polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polycarbonate (PC), polyphenylene ether (PPE), modified PPE, polyphenylene sulfide (PP ), Polybutylene terephthalate (PBT), polybenzimidazole (PBI), wholly aromatic polyester (POB), and the like. Such a thermoplastic resin is impregnated and / or applied and / or mixed with the fiber sheet or the fiber mat to give a thermoplastic sheet having excellent molded shape retention and rigidity.

  The above thermoplastic resins may be used in combination of two or more, and may be used by mixing one or more of a certain amount of thermosetting resin to the extent that it does not inhibit the thermoplastic resin of the thermoplastic sheet. . The thermoplastic resin is preferably in the form of an aqueous solution, an aqueous emulsion, or an aqueous dispersion from the viewpoint of easy handling, but may be in the form of an organic solvent solution.

Examples of the thermosetting resin include urethane resin, melamine resin, thermosetting acrylic resin, particularly thermosetting acrylic resin that cures by forming an ester bond by heating, urea resin, phenol resin, epoxy resin, thermosetting type Polyester or the like is used, but urethane resin prepolymer, urea resin prepolymer (initial condensate), phenol resin prepolymer (initial condensate), diallyl phthalate prepolymer, acrylic oligomer, polyisocyanate that produce the synthetic resin. Synthetic resin precursors such as prepolymers such as narate, methacrylic ester monomers and diallyl phthalate monomers, oligomers and monomers may be used. The thermosetting resin is preferably used in the form of an aqueous solution, an aqueous emulsion, or an aqueous dispersion because it is easy to handle, but may be used in the form of an organic solvent solution.
Two or more of the above thermosetting resins or synthetic resin precursors may be used in combination.
The addition of the synthetic resin, particularly the thermosetting resin, improves both the shape retention and rigidity of the water-repellent laminated fiber sheet and the fiber mat.

  Further, a phenolic resin is particularly desirable as the resin used in the present invention. The phenolic resin can be obtained by condensing a phenolic compound with formaldehyde and / or a formaldehyde donor.

In order to coat and impregnate the water-repellent laminated fiber sheet and / or the fiber mat with the synthetic resin or the like, the sound absorbing material or the porous sheet is usually immersed in an aqueous emulsion or aqueous dispersion of the synthetic resin, or a knife Apply with a coater, roll coater, flow coater, etc.
In order to adjust the amount of resin in the water-repellent laminated fiber sheet or fiber mat impregnated or coated with the resin, after impregnating or applying the resin, the water-repellent laminated fiber sheet or fiber mat is squeezed using a squeeze roll or a press machine. Squeeze. In this case, the thickness of the water-repellent laminated fiber sheet or fiber mat is reduced. If the fiber mat is made of low-melting fibers or contains low-melting fibers, the water-repellent laminated fiber sheet or fiber mat is impregnated before the resin impregnation. It is desirable to heat the fiber mat to melt the low melting point fibers and bind the fibers with the melt. Then, the strength and rigidity of the fiber mat are further improved, the workability at the time of resin impregnation is improved, and the restoration of the thickness after drawing becomes remarkable.
After impregnating or applying the resin to the fiber mat, the water-repellent laminated fiber sheet or the fiber mat is dried at room temperature or by heating.

[Manufacture of sound absorbing materials]
The sound absorbing material according to the present invention is manufactured by laminating the water-repellent laminated fiber sheet and the fiber mat. The water repellent laminated fiber sheet may be laminated on the surface (one side or both sides) of the fiber mat, or the water repellent laminated fiber sheet may be inserted in the middle of the fiber mat. In this case, the water-repellent laminated fiber sheet is sandwiched between the fiber mats.
The number of water-repellent laminated fiber sheets inserted in the middle of the fiber mat is not limited to one, and a plurality of water-repellent laminated fiber sheets may be inserted into the fiber mat if desired.
The water-repellent laminated fiber sheet and the fiber mat are bonded by a breathable adhesive layer in the same manner as when the pulp fiber sheet and the organic synthetic fiber sheet are laminated. The breathable adhesive layer can be applied by, for example, spreading hot melt adhesive powder, interposing a web-like hot melt adhesive layer, spraying a solution or aqueous emulsion by spray coating, silk printing, offset printing, etc. It is formed by the method of apply | coating to a shape or a line | wire. When distributing hot melt adhesive powder, from the viewpoint of improving sound absorption performance, the particle size by the sieving method of hot melt adhesive powder is in the range of 80 to 500 μm, softening temperature is in the range of 80 to 180 ° C. the amount is preferably in the range of 2 to 40 g / ^{m 2.}

3 and 4 are sectional views of a sound absorbing material as one embodiment of the present invention.
FIG. 3 shows that a water-repellent laminated fiber sheet 5 in which a pulp fiber sheet 2 and an organic synthetic fiber sheet 3 are bonded via a breathable adhesive layer 4 is bonded to the surface of the fiber mat 6 via a breathable adhesive layer 14. The sound-absorbing material 1 is shown.
FIG. 4 shows a fiber mat 6A on both sides of a water-repellent laminated fiber sheet 5A obtained by bonding a pulp fiber sheet 2A and an organic synthetic fiber sheet 3A via a breathable adhesive layer 4A, and breathable adhesive layers 14A and 14B. , 6B is shown.

  The sound absorbing material may be formed in a predetermined shape. A thermoplastic resin is applied and / or impregnated and / or mixed with the fiber sheet and / or fiber mat which is a component of the sound absorbing material, or the fiber mat is made of low-melting fiber, or low-melting fiber is used. If included, the sound absorbing material is hot-pressed at a temperature equal to or lower than the softening temperature of the thermoplastic resin or low-melting fiber, or is cold-pressed after being heated above the softening temperature.

  In the case where a thermosetting resin is applied and / or impregnated and / or mixed with the fiber sheet and / or the fiber mat, the fiber sheet and / or the fiber mat is treated with a curing temperature of the thermosetting resin or Hot press at higher temperature.

  For example, as shown in FIG. 5, the sound absorbing material is used as the sound absorbing material 21 incorporated in the sound insulation wall panel 10 having the surface material 7 such as punching metal, or as shown in FIG. It is molded and used as the sound absorbing material 31 of the sound insulation wall panel 20. Since the sound-absorbing material of the present invention can provide high sound-absorbing performance even if it is thinner than the conventional sound-absorbing material, the sound-insulating wall panels 10 and 20 can be reduced in weight.

  Examples for describing the present invention more specifically will be described below, but the present invention is not limited to these examples.

[Example 1]
An organic synthetic fiber sheet, which is a needle punched nonwoven fabric having a basis weight of 120 g / m ^{2 made} of polyester fiber, was produced.
Next, wood pulp composed of 80 parts by weight of softwood pulp and 20 parts by weight of hardwood pulp is used as a raw material, and the beating degree is JIS P 8121-1995 4. It is beaten to a Canadian standard freeness of 500 ml (CSF) as defined by Canadian Standard Freeness, and after a normal paper making process, the crepe rate is 20%, the basis weight is 28 g / m ² , and the ventilation resistance is 0.83 kPa. A s / m pulp fiber sheet was produced.
On one side of the organic synthetic fiber sheet, a hot-melt adhesive powder made of polyamide resin with a softening point of 120 ° C. and a particle size of 200 to 500 μm is applied in a spreading amount of 3 g / m ² to form a breathable adhesive layer, and then applied. The pulp fiber sheet was laminated on the surface, and pressure-bonded with a heating roll at 150 ° C. to produce a laminated fiber sheet having the pulp fiber sheet lined on the organic synthetic fiber sheet.
Applying a fluorine-based water repellent (solid content: 5% by mass aqueous dispersion) to the laminated fiber sheet with a roll so that the impregnation amount is 2% by mass as a solid content, and then drying at 140 to 150 ° C. A water-repellent laminated fiber sheet having a ventilation resistance of 1.02 kPa · s / m was produced.
The obtained water-repellent laminated fiber sheet was free from peeling, swelling, shrinkage, and distortion between the pulp fiber and the organic synthetic fiber sheet.
Next, 30 parts by mass of a core-sheath type composite fiber (fineness: 6.6 dtex, fiber length: 75 mm) made of polyester fiber and having a sheath part having a melting point of 130 ° C. and normal polyester fiber (fineness: 2.2 dtex, fiber length) : 60 mm), and a fiber mat having a basis weight of 500 g / m ² by a thermal bond method, a thickness of 50 mm, and a ventilation resistance of 0.07 kPa · s / m was prepared.
Furthermore, the same hot-melt adhesive powder as that used for the breathable adhesive layer was applied to one surface of the fiber mat at a spraying amount of 5 g / m ² , and the water-repellent laminated fiber sheet pulp fiber was applied to the coated surface. The sheet side is laminated, heated to 150 ° C. while sucking, and the water-repellent laminated fiber sheet and the fiber mat are bonded and laminated. The sound absorbing material having a thickness of 50 mm and a ventilation resistance of 1.22 kPa · s / m (No. 1) Was made.

[Comparative Example 1]
A needle punching nonwoven fabric having a basis weight of 150 g / m ^{2 made} of polyester fiber is prepared, and the nonwoven fabric is filled with the fluorine-based water repellent used in Example 1 in an amount of 2% by mass with respect to the nonwoven fabric. After coating, a water repellent nonwoven fabric sheet having a ventilation resistance of 0.04 kPa · s / m was produced by drying at 140 to 150 ° C.
Next, a fiber sheet made of the same components as the fiber mat used in Example 1 and having a basis weight of 2500 g / m ² by a thermal bond method, a thickness of 50 mm, and a ventilation resistance of 1.26 kPa · s / m was produced.
On one side of the fiber sheet, the same hot melt adhesive powder as in Example 1 was applied in an amount of 5 g / m ² , the water-repellent nonwoven sheet was laminated on the coated surface, and the temperature was increased to 150 ° C. while sucking. A heat absorbing material (No. 2) having a thickness of 50 mm and a ventilation resistance of 1.31 kPa · s / m was prepared by heating and bonding the water-repellent nonwoven fabric sheet and the fiber sheet.

[Comparative Example 2]
In Comparative Example 1, a sound absorbing material having a thickness of 50 mm and a ventilation resistance of 0.13 kPa · s / m was similarly used except that the basis weight of the fiber sheet was 500 g / m ² and the ventilation resistance was 0.07 kPa · s / m. .3) was produced.

〔performance test〕
The sound absorbing material No. obtained in Example 1 and Comparative Examples 1 and 2 were used. 1, no. 2, no. The performance test results of 3 are shown in Table 1.

From the test results, the sound absorbing material No. 1 of Example 1 was used without using a pulp fiber sheet as in the conventional sound absorbing material. When a sound-absorbing material having the same level of sound-absorbing performance as that of the sound absorbing material No. As can be seen from Fig. 2, the weight is about 4 times.
Further, the sound absorbing material No. 1 of Example 1 was used without using a pulp fiber sheet. The sound absorbing material No. 1 of Comparative Example 2 having the same weight as that of No. 1 was used. 3 indicates that the sound absorption performance is significantly reduced.

[Example 2]
The sound absorbing material No. 1 obtained in Example 1 was used. A sound insulating wall panel 1 was built in a punching metal container made of an aluminum material shown in FIG.
The sound insulation wall panel was lighter than the conventional one and excellent in sound absorption.

Example 3
In the laminated fiber sheet used in Example 1, 20 parts by mass of a phenol-alkylresorcin-formaldehyde initial condensation resin (solid content: 40% by mass aqueous solution) as a thermosetting resin, and a fluorine-based water repellent (solid content) as a water repellent. : 5% by mass aqueous dispersion) After impregnating a mixed solution of 5 parts by mass and 75 parts by mass of water with a roll so as to be 20% by mass of the laminated fiber sheet as a solid content, heat drying at 140 ° C. The water-repellent laminated fiber sheet was prepared with the thermosetting resin in the B state. The weight of this product was 180 g / m ² , and the ventilation resistance was 1.20 kPa · s / m.
Next, 30 parts by mass of a core-sheath type composite fiber (fineness: 6.6 dtex, fiber length: 75 mm) made of polyester fiber and having a sheath part having a melting point of 130 ° C. and normal polyester fiber (fineness: 2.2 dtex, fiber length) : 60 mm) 70 parts by mass, and a fiber sheet having a basis weight of 200 g / m ² by a thermal bond method and a thickness of 30 mm is impregnated with a roll so that the thermosetting resin becomes 10% by mass of the fiber sheet. Then, the fiber mat was produced by heating and drying at 140 ° C. to change the thermosetting resin to the B state. This product weighed 220 g / m ² and had a ventilation resistance of 1.43 kPa · s / m.
Further, the fiber mat is laminated on the pulp fiber sheet side of the water-repellent laminated fiber sheet, and is molded to a thickness of 25 mm with a 180 ° C. hot press machine, and has a weight of 400 g / m ² , a ventilation resistance of 2 A sound absorbing material of .63 kPa · s / m was produced.
The sound insulating wall panel in which the obtained sound absorbing material was incorporated in a punching metal container similar to that of Example 2 was excellent in water repellency of the sound absorbing material and the sound absorbing performance of the sound insulating wall panel, and was lightweight and easy to handle.

  Since the sound-absorbing material of the present invention is lightweight and excellent in sound-absorbing performance, it is particularly useful as, for example, a sound-insulating wall panel on an expressway and can be used industrially.

1,11,21,31 Sound absorbing material 2,2A Pulp fiber sheet 3,3A Organic synthetic fiber sheet 4,4A, 14,14A, 14B Breathable adhesive layer 5,5A Water repellent laminated fiber sheet 6,6A, 6B Fiber Mat 7 Surface material 10, 20 Sound insulation wall panel

Claims (4)

  The beating degree is JIS P 8121-1995. It contains 90% by mass or more of a porous pulp fiber in the range of 350 to 650 ml (CSF) with a Canadian standard freeness specified by Canadian Standard Freeness, and a ventilation resistance of 0.08 to 3.00 kPa · s / m. It is characterized by comprising a water repellent laminated fiber sheet obtained by impregnating a laminated fiber sheet with an organic synthetic fiber sheet lined through a breathable adhesive layer on a pulp fiber sheet, and a water mat, and a fiber mat. Sound absorbing material. Sound absorbing material according to claim 1 basis weight of the organic synthetic fiber sheet is 10 to 200 g / ^{m 2.} The basis weight of the pulp fiber sheet is 10 to 50 g / ^{m 2,} the sound absorbing material according to claim 1 or claim 2 basis weight of the fiber mat is 200 to 2000 g / ^{m 2.} A sound insulation wall panel comprising the sound absorbing material according to any one of claims 1 to 3.