JP2010096979A - Sound-absorbing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight sound-absorbing material with superior sound-absorbing performance. <P>SOLUTION: Paper (3) is composed of pulp fibers with a beating degree, expressed as a Schopper freeness of 15° SP to 30° SP, specified by JIS P 8121-1995 5 and the Shopper freeness test method, and ventilation resistance is set at 0.05 to 3.0 kPa s/m, is inserted in a porous sheet (2); and the sheet (3) is disposed at a depth side of 6/10 to 9/10 of thickness of the porous sheet (2) from a surface in which noise comes, thereby the sound absorbing material (1) is constituted having improved sound-absorbing performance of the porous sheet (2). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sound-absorbing material such as a flooring material for automobiles and a wall material for houses.

  In recent years, due to problems such as soaring prices of petroleum resources and global warming, improvement of fuel efficiency has become an urgent issue particularly in the automobile industry. On the other hand, in order to improve the performance, it is necessary to take a soundproofing measure for the inside and outside of the car, and various sound absorbing materials have been proposed.

  For example, Patent Document 1 describes a sound absorbing felt made of a single layer felt. Patent Document 2 describes an automobile interior material made of a resin binder-attached fiber web. Further, Patent Document 3 describes an automotive insulator configured by a laminate of a sound absorbing layer made of a fiber assembly and a skin layer made of a foam material.

JP 2005-195989 A JP 2004-325993 A Japanese Patent Laid-Open No. 2003-081028

However, the conventional invention has the following problems. For example, a sound-absorbing material for automobiles or building wall materials is made of a porous material such as a fiber sheet or a plastic foam, but it is necessary to increase the thickness in order to ensure sound-absorbing performance. For this reason, the weight of the sound absorbing material is considerably large. This leads to a deterioration in workability due to an increase in weight, and particularly in the case of an automobile, which is disadvantageous in terms of reducing fuel consumption and weight. Specifically, in the invention of Patent Document 1, the air flow resistance value between the one surface layer and the opposite surface layer of the felt is continuously changed by the difference in the coating amount of the binder resin, but the weight is 1500 g / m ² and becomes large. In addition, the invention of Patent Document 2 also has a weight of 1750 g / m ² as an interior material. Moreover, although the invention of the said patent document 3 is weight-reduced, since a foaming layer becomes the surface, there exists a problem that surface strength is weak.

  The present invention has been made paying attention to such problems existing in the prior art, and the object of the present invention is to provide a sound-absorbing material capable of reducing the weight while maintaining a suitable sound-absorbing performance. It is to provide.

In the present invention, the beating degree is JIS P 8121-1995. A layer of paper (3) comprising pulp fibers with a shopper freeness of 15 ° SR to 30 ° SR as defined in the shopper freeness test method, and having a ventilation resistance of 0.05 to 3.0 kPa · s / m or Two or more layers are the sound absorbing material (1) inserted in the porous sheet (2), and the paper (3) inserted in the noise incident surface side is more porous than the surface of the porous sheet (2). The sound-absorbing material (1) inserted on the rear side of the thickness of 6/10 to 9/10 is provided.
The sound absorption material (1) preferably has a ventilation resistance of 0.1 to 5.0 kPa · s / m, and the paper (3) is subjected to creping and / or embossing so that the surface has a large number of irregularities. It is desirable that it be formed.
Further, the paper (3) and / or the porous sheet (2) has a ventilation resistance adjusted by applying and / or impregnating and / or mixing a synthetic resin and / or a synthetic resin precursor. The porous sheet (2) is preferably composed of a multilayer of a plurality of unit porous sheets, and the paper (3) is preferably inserted between the unit porous sheets.
Furthermore, it is desirable that the paper (3) and the unit porous sheet are bonded by a breathable adhesive layer, and the sound absorbing material (1) may be formed into a predetermined shape.

[Action]
It is called beating that the pulp fibers are mechanically beaten and ground. When pulp fibers are beaten, the fibers are branched into films, or concentrically loosened and the fibers become porous, and are obtained when paper is made using such beaten pulp fibers. The pores between the porous pulp fibers of the paper can be enlarged, and a paper having a low density and excellent sound absorption characteristics can be obtained. However, the beating degree of the pulp fiber is JIS P 8121-1995. When the shopper freeness of 30 ° SR specified in the shopper freeness test method is exceeded, the fibrillation of the pulp fibers proceeds, the fine fibers increase, the paper density increases, and the sound absorption characteristics deteriorate. On the other hand, if the beating degree of the pulp fiber is less than 15 ° SR, the pulp fiber becomes insufficiently porous or concentric, and the porosity is lowered to deteriorate the sound absorption characteristics.

  When such paper (3) is inserted into the porous sheet (2), the sound absorbing property of the sound absorbing material (1) is improved and the thickness of the porous sheet (2) can be reduced. When the paper (3) inserted into the sheet is inserted into the depth side of the porous sheet (2) from 6/10 to 9/10 from the surface, the sound absorbing material (1) There is provided a sound-absorbing material (1) which is lightweight even when the thickness is 10 mm or more and which is not only sound-absorbing performance only in a specific sound range but is stable in a wide sound range from a middle sound range to a high sound range and excellent in sound-absorbing performance.

When the paper (3) is subjected to creping and / or embossing to form a large number of irregularities on the surface, when the sound wave is applied, the paper (3) resonates and vibrates, resulting in attenuation of the sound wave. Therefore, the sound absorption characteristics are improved.
When the synthetic resin and / or the synthetic resin precursor is applied and / or impregnated and / or mixed with the paper (3) and / or the porous sheet (2), the paper 3 and / or the porous sheet. The rigidity of (2) is improved, and the ventilation resistance can be arbitrarily adjusted in the range of 0.1 to 5.0 kPa · s / m.

  Usually, in the sound-absorbing material (1) of the present invention, the porous sheet (2) is composed of a multilayer of a plurality of unit porous sheets, and the paper (3) is inserted between the unit porous sheets. Yes. In such a configuration, when the paper (3) and the unit porous sheet are bonded by the air-permeable adhesive layer, the air-permeability is not inhibited by the adhesive layer, and the air-flow resistance is 0.1 to 5.0 kPa. -Easily secured in the range of s / m.

〔effect〕
In the present invention, there is provided a sound-absorbing material that is lightweight and excellent in sound-absorbing characteristics even when the thickness is large.

〔paper〕
The paper used in the present invention is made of softwood or hardwood chips and has a beating degree of JIS P 8121-1995. It consists of pulp fibers in the range of 15 ° SR to 30 ° SR of shopper freeness specified by the shopper freeness test method.
The above beating is usually performed by a conical refiner, a disc refiner, or the like. When the beating degree of the pulp fiber is less than 15 ° SR, the pulp fiber is not made porous or concentric, and the porosity is lowered to adversely affect the sound absorbing performance of the sound absorbing material. On the other hand, when the temperature exceeds 30 ° SR, the fibrillation of the pulp fibers proceeds, the fine fibers increase, the paper density increases, and the sound absorbing properties of the sound absorbing material are adversely affected.
The airflow resistance of the paper is set to be 0.05 to 3.0 kPa · s / m. When the ventilation resistance is less than 0.05 kPa · s / m, the density of the paper becomes too low, and the strength and rigidity of the paper are lowered. On the other hand, if the ventilation resistance exceeds 3.0 kPa · s / m, the density of the paper increases and the sound absorption characteristics become insufficient.
If desired, the paper may be creped and / or embossed to form crimped ridges and numerous protrusions on the surface.

For the creping process, wet crepes that are compressed in the longitudinal direction (making direction) using a press roll or doctor blade in the state of wet paper and brazed, and the sheet is dried with a Yankee dryer or calender, and then the doctor There is a dry crepe in which brazing is performed by compressing in the vertical direction using a blade or the like. For example, the creped paper desirably has a crepe rate of 10 to 50%.
Here, the crepe rate is
Crepe rate (%) = (A / B) × 100 (A is the paper making speed in the paper manufacturing process, B is the paper winding speed)
In other words, the crepe rate is the ratio at which the paper web made of pulp fibers is compressed in the longitudinal direction (making direction) by creping (reference: JP-A-2002-327399, JP-T-10-510886).
Here, if the crepe rate is less than 10%, the improvement in sound absorption performance due to creping is not significant. On the other hand, if the crepe rate exceeds 50%, wrinkles easily occur during molding.
The embossed paper is formed by pressing a roll (embossing roll) or plate (embossing plate) with 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 height is 0.02 to 2.00 mm and the number of protrusions is 20 to 200 / cm ² . If the protrusion height is less than 0.02 mm, the improvement in sound absorption performance by embossing is not significant, and if the protrusion height exceeds 2.00 mm, wrinkles are likely to occur during molding. Moreover, if the number of protrusions is less than 20 pieces / cm ² , the improvement in sound absorption performance by embossing is not significant, and if the number of protrusions exceeds 200 pieces / cm ² , the sound absorption performance of embossed paper is improved. Can not be seen. In FIG. 1, a large number of protrusions p are formed on the embossed paper 1a, and the protrusion height corresponds to “h” shown in FIG.
In the embossing step, if creped paper is used as the base paper, embossed creped paper can be obtained.

Basis weight of the paper 10 to 50 g / ^{m 2} is desirable. When the basis weight is less than 10 g / m ² , the moldability is lowered and wrinkles are likely to occur during molding. On the other hand, when the basis weight exceeds 50 g / m ² , the mass increases and the moldability decreases. .

The paper has a ventilation resistance of 0.05 to 3.0 kPa · s / m.
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).

  The airflow resistance of the paper of the present invention is appropriately set according to the frequency required in the final product. The ventilation resistance is adjusted by adjusting the beating degree of paper pulp fibers, the entanglement and basis weight of the fibers, and the coating amount of the synthetic resin and / or synthetic resin precursor to be applied and / or impregnated and / or mixed. Can do.

[Porous sheet]
As the porous sheet used in the present invention, a fiber sheet is usually used.
[Fiber sheet]
Examples of the fiber material of the fiber sheet used in the present invention include polyester fibers, polyethylene fibers, polypropylene fibers, polyamide fibers, acrylic fibers, urethane fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, synthetic fibers such as acetate fibers, and corn. Biodegradable fiber made of starch extracted from plants such as sugarcane and sugarcane, natural fiber such as pulp, cotton, palm fiber, hemp fiber, bamboo fiber and kenaf fiber, inorganic such as glass fiber, carbon fiber, ceramic fiber and asbestos fiber One or two or more types of recycled fibers obtained by defibrating fibers or scraps of textile products using these fibers are used. For example, glass fibers, carbon fibers, ceramic fibers, asbestos fibers , Inorganic fiber such as stainless steel fiber, polymetaphenylene isophthalamide fiber, poly- -Extremely high heat resistance if heat-resistant synthetic fibers with a melting point of 250 ° C or higher, such as aramid fibers such as phenylene terephthalamide fibers, polyarylate fibers, alumina fibers, polyether ether ketone fibers, polyphenylene sulfide fibers, etc. A sound-absorbing skin material is obtained. Among them, carbon fiber is a useful inorganic fiber because it can be incinerated and is difficult to disperse fine pieces, and aramid fiber is a useful synthetic fiber because it is relatively inexpensive and easily available.

Moreover, the low melting-point thermoplastic fiber whose melting | fusing point is 180 degrees C or less can be used for a fiber sheet as all or one part of the said fiber.
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 are sheath-type fibers. When the core-sheath fiber is used, the rigidity and heat resistance of the obtained fiber sheet are not lowered.

  The fiber sheet of the present invention is a method in which the fiber web sheet or mat is entangled by needle punching, a spunbond method, the fiber web sheet or mat is made of the low-melting thermoplastic fiber, or the above When low-melting thermoplastic fibers are mixed, the fiber web sheet or mat is heated to soften the low-melting thermoplastic fibers to bond them, or the fiber web A chemical bond method in which a synthetic resin binder is impregnated or mixed with a sheet or mat, or the sheet or mat of the fiber web is entangled by needle punching, and then the low-melting thermoplastic fiber is heated and softened. Stitch bond method to bind or sew with thread or high pressure Spunlace entangled in the flow, a method of forming wear impregnated with the synthetic resin binder into a sheet or mat subjected to the needle punching, is further produced by a method in which woven knitted the fibers.

In addition to the fiber sheet, in the present invention, for example, a breathable plastic such as a breathable polyurethane foam, a breathable polyethylene foam, a breathable polypropylene foam, a breathable phenol resin foam, and a breathable melamine resin foam. A sheet made of a foam may be used.
In addition, the basis weight and thickness of the porous sheet according to the present invention can be arbitrarily set in principle, but may desirably be set to a basis weight of 150 to 800 g / m ² and a thickness of about 10 to 100 mm.

[Synthetic resin and / or synthetic resin precursor]
As described above, in the sound-absorbing material according to the present invention, a synthetic resin and / or a synthetic resin precursor may be applied and / or impregnated on paper and / or a porous sheet. As a synthetic resin and / or a synthetic resin precursor, a thermoplastic resin, a thermosetting resin, and a synthetic resin precursor are illustrated, for example.

  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 or applied to the fiber sheet, stretchable paper material, or breathable porous material 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 used in the form of an aqueous solution, an aqueous emulsion, or an aqueous dispersion from the viewpoint of easy handling, but may be used 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 is used. 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.
Addition of the synthetic resin, particularly thermosetting resin, improves both the shape retention and rigidity of the paper and porous sheet.

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

(Phenolic compounds)
The phenolic compound used in the phenolic resin may be a monohydric phenol, a polyhydric phenol, or a mixture of a monohydric phenol and a polyhydric phenol. When only monohydric phenol is used, formaldehyde is easily released during and after curing. Therefore, polyhydric phenol or a mixture of monohydric phenol and polyhydric phenol is preferably used.

(Monohydric phenol)
Examples of the monohydric phenol include phenol, alkylphenols such as o-cresol, m-cresol, p-cresol, ethylphenol, isopropylphenol, xylenol, 3,5-xylenol, butylphenol, t-butylphenol, and nonylphenol, and o-fluoro. Phenol, m-fluorophenol, p-fluorophenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, o-iodophenol, m-iodo Phenol, p-iodophenol, o-aminophenol, m-aminophenol, p-aminophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitro Examples include monohydric phenol substitutes such as enol and 2,4,6-trinitrophenol, and polycyclic monohydric phenols such as naphthol. These monohydric phenols may be used alone or in combination of two or more. I can do it.

(Polyhydric phenol)
Examples of the polyhydric phenol include resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol, dihydroxynaphthalene, and the like. These polyhydric phenols are used alone or in combination of two or more. can do. Among the polyhydric phenols, preferred is resorcin or alkylresorcin, and particularly preferred is alkylresorcin, which has a higher reaction rate with aldehyde than resorcin.

Examples of the alkyl resorcin include, for example, 5-methyl resorcin, 5-ethyl resorcin, 5-propyl resorcin, 5-n-butyl resorcin, 4,5-dimethyl resorcin, 2,5-dimethyl resorcin, 4,5-diethyl resorcin, 2 , 5-diethyl resorcin, 4,5-dipropyl resorcin, 2,5-dipropyl resorcin, 4-methyl-5-ethyl resorcin, 2-methyl-5-ethyl resorcin, 2-methyl-5-propyl resorcin, 2 , 4,5-trimethylresorcin, 2,4,5-triethylresorcin and the like. A polyhydric phenol mixture obtained by dry distillation of an Estonia oil shale is inexpensive and contains a large amount of highly reactive various alkylresorcins in addition to 5-methylresorcin. Therefore, it is a particularly preferable polyhydric phenol raw material in the present invention.
Among the polyhydric phenols, one or a mixture of two or more resorcinol compounds such as resorcin and alkylresorcin (including polyhydric phenol mixture obtained by dry distillation of Estonian oil shale), aldehyde and / or aldehyde donation The resorcinol-based resin composed of a body is preferably used as the phenolic resin of the present invention.

(Formaldehyde donor)
In the present invention, the phenolic compound is condensed with formaldehyde and / or a formaldehyde donor, and the formaldehyde donor means a compound that forms and provides formaldehyde when decomposed or a mixture of two or more thereof. Examples of such aldehyde donors include paraformaldehyde, trioxane, hexamethylenetetramine, tetraoxymethylene and the like. In the present invention, formaldehyde and formaldehyde donor are collectively referred to as formaldehyde hereinafter.

(Manufacture of phenolic resins)
There are two types of the phenolic resin, a resole obtained by reacting with an alkali catalyst with an excess of formaldehyde with respect to the phenolic compound, and an acid catalyst with an excess of phenol with respect to the formaldehyde. There are novolaks obtained by reacting, and resole consists of a mixture of various phenol alcohols added with phenol and formaldehyde, usually provided in aqueous solution, novolac is a variety of dihydroxydiphenylmethane series in which phenol is further condensed with phenol. It consists of a derivative and is usually provided as a powder.
In the phenolic resin used in the present invention, first, the phenolic compound and formaldehyde are condensed to form an initial condensate, and after the initial condensate is adhered to the fiber sheet, a curing catalyst and / or Resinized by heating.
In order to produce the above condensate, monohydric phenol and formaldehyde may be condensed to form a monohydric phenol single initial condensate, or a mixture of monohydric phenol and polyhydric phenol may be condensed with formaldehyde. The monohydric phenol-polyhydric phenol initial cocondensate may be used. In order to produce the initial condensate, either one or both of monohydric phenol and polyhydric phenol may be used as the initial condensate in advance.

In the present invention, a desirable phenolic resin is a phenol-alkylresorcin cocondensate. The phenol-alkylresorcin cocondensate is stable in an aqueous solution of the cocondensate (initial cocondensate) and is stored for a long time at room temperature as compared with a condensate (initial condensate) composed only of phenol. There is an advantage that you can. Further, the fiber sheet obtained by impregnating or applying the aqueous solution to the sheet base material and pre-curing is good, and the moldability is not lost even if the fiber sheet is stored for a long period of time. Furthermore, alkylresorcin has a high reactivity with formaldehydes and captures and reacts with a free aldehyde, so that it also has an advantage of reducing the amount of free aldehyde in the resin.
A desirable method for producing the phenol-alkylresorcin cocondensate is to first react phenol with formaldehyde to produce a phenolic resin initial condensate, and then add alkylresorcin to the phenolic resin initial condensate. If it becomes, it is a method of adding formaldehyde and reacting.

  For example, in the above-mentioned condensation of (a) monohydric phenol and / or polyhydric phenol and formaldehyde, usually 0.2 to 3 mol of formaldehyde is 1 mol of monohydric phenol and formaldehyde is 1 mol of polyhydric phenol. 0.1 to 0.8 mol of the compound and, if necessary, a solvent and a third component are added, and the mixture is heated and reacted at a liquid temperature of 55 to 100 ° C. for 8 to 20 hours. At this time, all the formaldehydes may be added at the start of the reaction, or may be added in divided portions or continuously.

  Furthermore, in the present invention, as the phenolic resin, if desired, urea, thiourea, melamine, thiomelamine, dicyandiamine, guanidine, guanamine, acetoguanamine, benzoguanamine, 2,6-diamino-1,3-diamine amino series An initial condensate composed of a resin monomer and / or the amino resin monomer may be added to cause co-condensation with the phenol compound and / or the initial condensate.

  During the production of the phenolic resin, before, during or after the reaction, for example, hydrochloric acid, sulfuric acid, orthophosphoric acid, boric acid, oxalic acid, formic acid, acetic acid, butyric acid, benzenesulfonic acid, phenolsulfonic acid, para Inorganic or organic acids such as toluenesulfonic acid, naphthalene-α-sulfonic acid, naphthalene-β-sulfonic acid, esters of organic acids such as dimethyl oxalate, acid anhydrides such as maleic anhydride, phthalic anhydride, Ammonium salts such as ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium oxalate, ammonium acetate, ammonium phosphate, ammonium thiocyanate, ammonium imidosulfonate, monochloroacetic acid or sodium salt thereof, organic halides such as α, α'-dichlorohydrin, Triethanolamine hydrochloride , Hydrochlorides of amines such as aniline hydrochloride, urea adducts such as urea adducts salicylate, urea stearate, urea adduct heptanoate, acidic substances such as N-trimethyltaurine, zinc chloride, ferric chloride, ammonia, amines Alkali metals such as sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, hydroxides of alkaline earth metals, oxides of alkaline earth metals such as lime, sodium carbonate, sodium sulfite, sodium acetate An alkaline substance such as weak acid salts of alkali metals such as sodium phosphate may be mixed as a catalyst or a pH adjuster.

The initial condensate (including the initial cocondensate) of the phenolic resin of the present invention may be further mixed with a curing agent such as the above formaldehydes or alkylolated triazone derivatives.
The alkylolated triazone derivative is obtained by a reaction of a urea compound, an amine and formaldehyde. Examples of the urea compounds used in the production of alkylolated triazone derivatives include alkyl ureas such as urea, thiourea and methylurea, alkylthioureas such as methylthiourea, phenylurea, naphthylurea, halogenated phenylurea, and nitrated alkyl. Examples thereof include urea alone or a mixture of two or more. A particularly desirable urea compound is urea or thiourea. In addition, amines such as aliphatic amines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine and amylamine, amines such as benzylamine, furfurylamine, ethanolamine, ethylenediamine, hexamethylenediamine and hexamethylenetetramine, as well as ammonia. These are used alone or as a mixture of two or more. The formaldehydes used in the production of the alkylolated triazone derivative are the same as the formaldehydes used in the production of the initial condensate of phenolic resin.
In the synthesis of the above-mentioned alkylolated triazone derivative, a ratio of 0.1 to 1.2 mol of amines and / or ammonia and a ratio of 1.5 to 4.0 mol of formaldehydes is usually 1 mol of urea compound. React with. In the above reaction, the order of addition is arbitrary, but as a preferred reaction method, first, the required amount of formaldehydes is charged into the reactor, and the amines and / or ammonia are usually kept at a temperature of 60 ° C. or lower. There is a method in which a required amount is gradually added, and a required amount of a urea compound is further added, followed by stirring and heating at 80 to 90 ° C. for 2 to 3 hours. As formaldehydes, 37% formalin is usually used, but a part thereof may be replaced with paraformaldehyde in order to increase the concentration of the reaction product. When hexamethylenetetramine is used, a reaction product having a higher solid content can be obtained. Reactions of urea compounds, amines and / or ammonia, and formaldehydes are usually carried out in aqueous solution, but instead of part or all of water, methanol, ethanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, etc. These alcohols may be used alone or as a mixture of two or more kinds, and water-soluble organic solvents such as ketones such as acetone and methyl ethyl ketone may be used alone or in combination of two or more kinds. The addition amount of the curing agent is 10 to 100 parts by mass with respect to 100 parts by mass of the initial condensate (initial cocondensate) of the phenolic resin of the present invention in the case of formaldehyde, and the phenol in the case of an alkylolated triazone derivative. It is 10 to 500 parts by mass with respect to 100 parts by mass of the initial condensate (initial cocondensate) of the resin.

(Sulfomethylation and / or sulfimethylation of phenolic resins)
In order to improve the stability of the water-soluble phenolic resin, it is desirable to sulfomethylate and / or sulfmethylate the phenolic resin.

(Sulfomethylating agent)
Examples of sulfomethylating agents that can be used to improve the stability of water-soluble phenolic resins include sulfite, bisulfite or metabisulfite, and alkali metals or quaternary amines or quaternary compounds such as trimethylamine or benzyltrimethylammonium. Examples thereof include water-soluble sulfites obtained by reacting with secondary ammonium and aldehyde adducts obtained by reacting these water-soluble sulfites with aldehydes.
Examples of the aldehyde adduct include formaldehyde, acetaldehyde, propionaldehyde, chloral, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, etc. An aldehyde adduct composed of formaldehyde and sulfite is, for example, hydroxymethanesulfonate.

(Sulfimethylating agent)
Sulfimethylating agents that can be used to improve the stability of water-soluble phenolic resins include aliphatic and aromatic aldehyde alkali metal sulfoxylates such as formaldehyde sodium sulfoxylate (Longalite) and benzaldehyde sodium sulfoxylate. Examples thereof include alkali metals such as sodium hydrosulfite and magnesium hydrosulfite, hydrosulfites (dithionates) of alkaline earth metals, and hydroxyalkanesulfinates such as hydroxymethanesulfinate.

When the above-mentioned phenolic resin initial condensate is sulfomethylated and / or sulfimethylated, a sulfomethylating agent and / or a sulfimethylating agent may be added to the initial condensate at an optional stage to obtain a phenolic compound and / or initial condensate. Is sulfomethylated and / or sulfimethylated.
The addition of the sulfomethylating agent and / or the sulfymethylating agent may be performed at any stage before, during or after the condensation reaction.

  The total amount of the sulfomethylating agent and / or sulfmethylating agent is usually 0.001 to 1.5 mol with respect to 1 mol of the phenol compound. When it is 0.001 mol or less, the hydrophilicity of the phenolic resin is not sufficient, and when it is 1.5 mol or more, the water resistance of the phenolic resin is deteriorated. In order to satisfactorily maintain performance such as curability of the initial condensate to be produced and physical properties of the resin after curing, the content is preferably about 0.01 to 0.8 mol.

  The sulfomethylating agent and / or sulfimethylating agent added to sulfomethylate and / or sulfmethylate the initial condensate reacts with the methylol group of the initial condensate and / or the aromatic ring of the initial condensate, A sulfomethyl group and / or a sulfimethyl group is introduced into the initial condensate.

  The aqueous solution of the precondensate of the phenolic resin thus sulfomethylated and / or sulfimethylated is stable in a wide range from acidic (pH 1.0) to alkaline, and in any of acidic, neutral and alkaline regions. Can be cured. In particular, when cured on the acidic side, residual methylol groups are reduced, and the cured product is not decomposed to generate formaldehyde.

〔Flame retardants〕
Moreover, a flame retardant may be added to the paper and / or the porous sheet. Examples of the flame retardant include phosphorus flame retardant, nitrogen flame retardant, sulfur flame retardant, boron flame retardant, bromine flame retardant, guanidine flame retardant, phosphate flame retardant, phosphate ester flame retardant, amino acid Resin-based flame retardant, expanded graphite, etc.
In the present invention, it is particularly desirable to use a powdery solid flame retardant which is hardly soluble or insoluble in water. A powdery solid flame retardant that is insoluble or insoluble in water imparts flame resistance excellent in water resistance and durability to the sound absorbing skin material and the sound absorbing material. In particular, since the fiber sheet and the breathable porous material of the present invention have a rough structure, the above-mentioned powdery solid flame retardant smoothly penetrates into the interior and imparts high flame retardancy or non-flammability.

  In the present invention, the fibers of the fiber sheet as the porous sheet are inorganic fibers such as metal fibers, carbon fibers, glass fibers and ceramic fibers, mineral fibers such as asbestos fibers, aramid fibers (aromatic polyamide fibers). When using non-combustible, flame-retardant, and flame-proof fibers such as wool (natural wool), etc., the flame-absorbing, flame-retardant, and flame-proofing of the sound-absorbing skin material and sound-absorbing material is possible without using the flame retardant described below. It becomes possible to impart sex.

  The synthetic resin or synthetic resin precursor used in the present invention further includes calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, Titanium oxide, iron oxide, zinc oxide, alumina, silica, colloidal silica, mica, diatomaceous earth, dolomite, gypsum, talc, clay, asbestos, mica, calcium silicate, bentonite, white carbon, carbon black, iron powder, aluminum powder, Inorganic fillers such as glass powder, stone powder, blast furnace slag, fly ash, cement, zirconia powder; natural rubber or derivatives thereof; styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene rubber Synthetic rubbers such as isoprene rubber and isoprene-isobutylene rubber; water-soluble polymers such as polyvinyl alcohol, sodium alginate, starch, starch derivatives, glue, gelatin, blood powder, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyacrylate, and polyacrylamide Organic gums such as wood powder, walnut powder, coconut powder, wheat flour and rice flour; higher fatty acids such as stearic acid and palmitic acid; higher alcohols such as palmityl alcohol and stearyl alcohol; butyryl stearate and glycerin Esters of fatty acids such as monostearate; fatty acid amides; natural waxes such as carnauba wax, synthetic waxes; paraffins, paraffin oil, silicone oil, silicone resin, fluororesin, polyvinyl Mold release agents such as alcohol and grease; organic compounds such as azodicarbonamide, dinitrosopentamethylenetetramine, P, P′-oxybis (benzenesulfonylhydrazide), azobis-2,2 ′-(2-methylgropionitrile) Foaming agent; inorganic foaming agent such as sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate; hollow particles such as shirasu balloon, perlite, glass balloon, foamed glass, hollow ceramics; plastic such as foamed polyethylene, foamed polystyrene, foamed polypropylene, etc. Foam and foam particles: pigments, dyes, antioxidants, antistatic agents, crystallization accelerators, phosphorus compounds, nitrogen compounds, sulfur compounds, boron compounds, bromine compounds, guanidine compounds, phosphate compounds Compounds, phosphate ester compounds, flame retardants such as amino resins, flame retardants, flame retardants, repellent Water, oil repellent, insect repellent, antiseptic, waxes, surfactants, lubricants, anti-aging agents, UV absorbers; phthalate plasticizers such as DBP, DOP, dicyclohexyl phthalate and other tricresyls A plasticizer such as phosphate may be added and mixed.

  Examples of the water / oil repellent according to the present invention include natural wax, synthetic wax, fluororesin, and silicon resin.

In order to apply or impregnate the synthetic resin to the paper or the porous sheet, the aqueous emulsion or aqueous dispersion of the synthetic resin is usually spray applied, or the paper or the porous sheet is immersed, or a knife coater Apply with a roll coater, flow coater or the like.
In order to adjust the amount of resin in the paper or porous sheet impregnated or coated with the resin, after impregnating or coating the resin, the paper or porous sheet is squeezed using a squeezing roll or a press machine. In this case, the thickness of the paper or porous sheet is reduced, but when the porous sheet is a fiber sheet, the fiber sheet is composed of low-melting fibers or contains low-melting fibers. It is desirable that the fiber sheet is heated before the resin impregnation to melt the low melting point fibers and the fibers are bound by the melt. As a result, the strength and rigidity of the fiber sheet are further improved, workability at the time of resin impregnation is improved, and restoration of the thickness after drawing becomes remarkable.
After impregnating or applying the resin to the fiber sheet, the fiber sheet is dried at room temperature or by heating.

[Sound absorbing material]
As shown in FIGS. 3D and 3E, a general method for producing the sound-absorbing material (1) of the present invention includes two or more unit porous sheets (2A1) and (2A2) of the porous sheet (2). And the paper (3) is inserted between the unit porous sheets (2A1) and (2A2). At this time, the thickness of the unit porous sheet (2A1) on the noise incident surface side is set to 6/10 to 9/10 of the total thickness of the sound absorbing material (1).

When the paper (3) is interpolated between the porous sheets (2A1) and (2A2) to form the sound absorbing material (1), it is an ordinary solution-type or water-emulsion-type adhesive, powder, or web-like shape. Solution type or aqueous emulsion type hot melt adhesives are used. In the case of a hot melt adhesive in the form of a powder or a web, a breathable adhesive layer is provided, so that the breathability can be secured and the breathability of the laminated material is not hindered.
In the case of a solution-type or aqueous emulsion-type adhesive, it is desirable to ensure the breathability of the laminated material by applying the adhesive in the form of dots by spray coating, silk printing coating, offset printing coating, or the like.
The ventilation resistance of the sound absorbing material (1) is preferably set in the range of 0.1 to 5.0 kPa · S / m. When the ventilation resistance exceeds 5.0 kPa · s / m, sound absorption characteristics and moldability are deteriorated.

  The ventilation resistance of the sound-absorbing material (1) of the present invention is appropriately set according to the required frequency. The ventilation resistance is adjusted by adjusting the beating degree of the pulp fibers of the paper (3), the entanglement and basis weight of the pulp fibers, the resin to be applied and / or impregnated and / or mixed, or the porous sheet (2). The density and ventilation resistance can be adjusted by the amount of resin applied and / or impregnated and / or mixed. If the resin to be applied and / or impregnated and / or mixed has adhesiveness, the adhesive layer may not be formed using a special adhesive.

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

[Example 1] (Production of paper and porous sheet)
<Paper 3A>
4. Raw material pulp consisting of 80% by weight of wood pulp and 20% by weight of non-wood pulp is JIS P 8121-1995 using a disc refiner. After papermaking with a shopper freeness of 26 ° SR specified in the shopper freeness test method, paper weight is 20 g / m ² , crepe rate is 28%, ventilation resistance is 0.623 kPa · s. A paper (3A) which is a creped paper of / m was obtained.

<Paper 3B>
4. Raw material pulp consisting of 80% by weight of wood pulp and 20% by weight of non-wood pulp is JIS P 8121-1995 using a disc refiner. After papermaking with a shopper freeness of 10 ° SR specified in the shopper freeness test method, paper weight is 20 g / m ² , crepe rate is 28%, and airflow resistance is 0.031 kPa · s. / M creped paper was obtained. Next, an acrylic ester resin emulsion was applied to the surface of the creped paper at a solid content of 50 g / m ² by a spray method and dried to obtain paper (3B) having a ventilation resistance of 0.630 kPa · s / m.

<Paper 3C>
4. Raw material pulp consisting of 80% by weight of wood pulp and 20% by weight of non-wood pulp is JIS P 8121-1995 using a disc refiner. After papermaking with a shopper freeness of 35 ° SR specified in the shopper freeness test method, paper weight is 20 g / m ² , crepe rate is 28%, air flow resistance is 3.34 kPa · s. A paper (3C) which is a creped paper of / m was obtained.

<Porous sheet 2A>
A fiber web having a basis weight of 300 g / m ² consisting of 70% by mass of polyester fiber (fineness: 15 dtex) and 30% by mass of low melting point polyester fiber (fineness: 4.4 dtex, melting point: 120 ° C.) was used as the porous sheet (2A). .

[Example 2]
Using the paper (3A) of Example 1 and the porous sheet (2A), a spider web-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3A) and the porous sheets (2A1) and (2A2), heated at 150 ° C. for 1 minute, and then the paper (3A) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 1 was obtained. In the figure, 4 is a noise source.

Example 3
Using the paper (3A) of Example 1 and the porous sheet (2A), a spider web-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3A) and the porous sheets (2A1) and (2A2), heated at 150 ° C. for 1 minute, and then the paper (3A) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material no. 2 was obtained.

[Comparative Example 1]
After heating for 1 minute at 150 ° C. using only the porous sheet (2A) of Example 1, it was molded into a plate shape with a cooling press molding machine, and molded sound-absorbing material No. 20 having a thickness of 20 mm with the arrangement shown in FIG. 11 was obtained.

[Comparative Example 2]
Using the paper (3A) of Example 1 and the porous sheet (2A), a spider web-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3A) and the porous sheet (2A) and heated at 150 ° C. for 1 minute, and then the paper 3A and the porous sheet 2A are bonded with a cooling press molding machine. The molded sound-absorbing material No. 20 having a thickness of 20 mm having the arrangement shown in FIG. 12 was obtained.

[Comparative Example 3]
Using the paper (3A) of Example 1 and the porous sheet (2A), a spider web-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3A) and the porous sheets (2A1) and (2A2), heated at 150 ° C. for 1 minute, and then the paper (3A) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 13 was obtained.

[Comparative Example 4]
Using the paper (3B) of Example 1 and the porous sheet (2A), a cobweb-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3B) and the porous sheet (2A) and heated at 150 ° C. for 1 minute, and then the paper (3B) and the porous sheet (2A) with a cooling press molding machine. Are molded and formed into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 22 was obtained.

[Comparative Example 5]
Using the paper (3B) of Example 1 and the porous sheet (2A), a cobweb-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3B) and the porous sheets (2A1) and (2A2) and heated at 150 ° C. for 1 minute, and then the paper (3B) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 23 was obtained.

[Comparative Example 6]
Using the paper (3B) of Example 1 and the porous sheet 2A, a cobweb-like hot melt adhesive made of a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. After interposing between the paper (3B) and the porous sheets (2A1) and (2A2) and heating at 150 ° C. for 1 minute, the paper (3B) and the porous sheet ( 2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 24 was obtained.

[Comparative Example 7]
Using the paper (3B) of Example 1 and the porous sheet (2A), a cobweb-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3B) and the porous sheets (2A1) and (2A2) and heated at 150 ° C. for 1 minute, and then the paper (3B) and the porous material with a cooling press molding machine. The sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material No. 20 having a configuration of FIG. 25 was obtained.

[Comparative Example 8]
A porous sheet having a thickness of 20 mm and mainly composed of ultrafine fibers composed of a web sheet having a basis weight of 400 g / m ² consisting of 65% by mass of polypropylene microfiber fibers (average diameter 2 μm) and 35% by mass of polyester fibers (fineness: 2.2 dtex). (2B) molded sound absorbing material No. 21 was manufactured (arrangement configuration of FIG. 3A ′).

[Comparative Example 9]
Using the paper (3A) of Example 1 and the porous sheet (2A), a spider web-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3A) and the porous sheet (2A) and heated at 150 ° C. for 1 minute, and then the paper (3A) and the porous sheet (2A) with a cooling press molding machine. Are molded into a plate shape, and the molded sound-absorbing material No. 20 having a thickness of 20 mm having the arrangement shown in FIG. 16 was obtained.

[Comparative Example 10]
Using the paper (3B) of Example 1 and the porous sheet (2A), a cobweb-like hot melt adhesive comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3B) and the porous sheet 2A and heated at 150 ° C. for 1 minute, and then the paper (3B) and the porous sheet (2A) are cooled with a cooling press molding machine. The molded sound-absorbing material No. 20 having a thickness of 20 mm having the arrangement configuration shown in FIG. 26 was obtained.

[Comparative Example 11]
A cobweb-like hot melt adhesive comprising the paper (3C) of Example 1 and the porous sheet (2A) and comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3C) and the porous sheet (2A) and heated at 150 ° C. for 1 minute, and then the paper (3C) and the porous sheet (2A) with a cooling press molding machine. Are molded into a plate shape, and the molded sound-absorbing material No. 20 having a thickness of 20 mm having the arrangement configuration shown in FIG. 32 was obtained.

[Comparative Example 12]
A cobweb-like hot melt adhesive comprising the paper (3C) of Example 1 and the porous sheet (2A) and comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3C) and the porous sheets (2A1) and (2A2) and heated at 150 ° C. for 1 minute, and then the paper (3C) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and formed into a plate shape, and the arrangement of FIG. 33 was obtained.

[Comparative Example 13]
A cobweb-like hot melt adhesive comprising the paper (3C) of Example 1 and the porous sheet (2A) and comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3C) and the porous sheets (2A1) and (2A2) and heated at 150 ° C. for 1 minute, and then the paper (3C) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the arrangement of FIG. 34 was obtained.

[Comparative Example 14]
A cobweb-like hot melt adhesive comprising the paper (3C) of Example 1 and the porous sheet (2A) and comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3C) and the porous sheets (2A1) and (2A2) and heated at 150 ° C. for 1 minute, and then the paper (3C) and the porous material with a cooling press molding machine. Sheets (2A1) and (2A2) are bonded and molded into a plate shape, and the molded sound-absorbing material no. 35 was obtained.

[Comparative Example 15]
A cobweb-like hot melt adhesive comprising the paper (3C) of Example 1 and the porous sheet (2A) and comprising a copolymerized polyamide (melting point: 130 ° C.) having a basis weight of 10 g / m ² as a breathable adhesive. An agent is interposed between the paper (3C) and the porous sheet (2A) and heated at 150 ° C. for 1 minute, and then the paper (3C) and the porous sheet (2A) with a cooling press molding machine. Are molded into a plate shape, and the molded sound-absorbing material No. 20 having a thickness of 20 mm having the arrangement shown in FIG. 36 was obtained.

  Table 1 shows the lamination position of the paper in the molded sound-absorbing material in each example and comparative example. FIG. 3A, B, C, D, E, F, A ′, B ′, C ′, D ′, E ′, F ′, A ″, B ″, C ″, D ″, E ″, F ″ are explanatory views of the arrangement configuration of the molded sound absorbing material in each example and comparative example.

  Table 1 and FIGS. 3A, B, C, D, E, F, A ′, B ′, C ′, D ′, E ′, F ′, A ″, B ″, C ″, D ″ Table 2 shows the measurement results of the sound absorption coefficient based on the airflow resistance and the normal incident sound absorption coefficient for each of the sound absorbing materials indicated by E, E ″ and F ″. The normal incident sound absorption coefficient was measured in an arrangement as shown in FIG. No. 1, no. 2 in FIG. 11, no. 12, no. 13 in FIG. 22, no. 23, no. 32, no. 33 is shown in FIG. 24, no. 25, no. 21 in FIG. 16, no. 26, no. 34, no. 35, no. FIG. 8 is a graph showing the sound absorption coefficient with respect to frequency in FIG.

The following can be understood with reference to Table 2 and FIGS.
Molded sound absorbing material No. 1, no. 2 and comparative molded sound absorbing material No. 12, no. No. 13, even if a sound absorbing material made of the same paper and porous sheet is used, even if the air resistance of the molded product is approximately the same depending on the position where the paper is inserted, the comparative molded sound absorbing material No. 12, no. In No. 13, the sound absorption rate decreases when the frequency is 3000 Hz or more.
No. In No. 11, the sound absorption coefficient is extremely bad because the ventilation resistance of the molded product itself is low.
No. 22, no. 23, no. 24, no. For paper No. 25, paper 3B adjusted to have a ventilation resistance equivalent to that of paper 3A by applying resin to paper using pulp fibers having a beating degree of 15 ° SR or less at the time of producing the sound absorbing material was used. Although it is a comparative molded sound absorbing material, no. 24, no. No. 25 is No. 22, no. Although the sound absorption coefficient is better than that of No. 23, No. 23 which is an example of the present invention. 1, no. Compared with 2, a decrease in the sound absorption coefficient is also observed in the frequency band of 3000 to 4000 Hz or higher.
No. No. 16, No. 26 has good ventilation resistance as a whole, but the position where the paper layer exceeds 9/10 as the distance from the sound source (10/10, that is, the porous sheet) It can be seen that the sound absorption performance does not improve on the opposite side of the sound source. No. It can be seen that 36 is the same.
No. 32, no. 33, no. 34, no. No. 35 has a beating degree of 30 ° SR or more and a large ventilation resistance (5.0 kPa · s / m or more), and it can be seen that the sound absorption performance is lowered at 1500 Hz or more.
No. The comparative molded sound-absorbing material consisting only of the porous sheet (2B) composed of 21 ultrafine fibers has a moderate airflow resistance and generally good sound absorption coefficient, but is inferior in attenuating sound-absorbing performance as compared with the examples of the present invention. This is because the pulp fiber used in the paper of the present invention is JIS P 8121-1995. By beating the shopper to a freeness of 15 ° SR to 30 ° SR specified in the shopper freeness test method, a large number of fine pores are formed on the pulp surface. It is considered that the material has appropriate ventilation resistance and good sound absorption performance. Moreover, when this paper is arranged on the porous sheet, if it is arranged at a position 6/10 to 9/10 depth from the sound source side, the sound absorbing performance is not deteriorated even at 3000 Hz or higher. The reason why the sound absorption performance does not improve even when using paper whose pulp resistance is 15 ° SR or less and the resin is coated to adjust the airflow resistance is because the influence of the beating degree at the time of pulp beating is large. Seem.

Example 4
A fiber web having a basis weight of 150 g / m ² consisting of 70% by mass of polyester fibers (fineness: 6.0 dtex) and 30% by mass of low-melting polyester fibers (fineness: 4.4 dtex, melting point: 120 ° C.) is heat-cooled, A porous sheet (2C) having a thickness of 30 mm was obtained. Similarly, a porous sheet (2D) having a basis weight of 2000 g / m ² and a thickness of 90 mm was obtained.
Separately, a raw material pulp made of wood pulp is JIS P 8121-1995 by a disc refiner. After papermaking by beating at a shopper freeness 25 ° SR specified in the shopper freeness test method, crepe embossed paper (weight per unit area 18 g / m ² , crepe rate: 25%, protrusion height: Paper (3D) having 0.3 mm, the number of protrusions: 9 pieces / cm ² , and airflow resistance: 0.307 kPa · s / m) was obtained.

  Next, the porous sheet 2C is overlaid on three layers (2C1), (2C2), (2C3) (total thickness: 90 mm), and the paper (3D) is placed on the porous sheets (2C1), (2C2), ( 2C3), a sound-absorbing material having a structure as shown in FIG. 9 was manufactured, and ventilation resistance and normal incidence sound absorption coefficient were measured. The results are shown in Table 3 and FIG. The sound source 4 at the time of measuring the normal incident sound absorption coefficient was measured as shown in FIG.

  From Table 3 and FIG. 3 shows that the sound absorption performance is stable from a low frequency to a high frequency. Comparative molded sound absorbing material No. No. 37 has a relatively stable sound absorbing performance, but the molded sound absorbing material No. Compared with 3, the sound absorption performance is inferior. Comparative molded sound absorbing material No. 39, no. No. 40 has a frequency of 800 Hz or more, and the sound absorption coefficient greatly fluctuates up and down. Comparative molded sound absorbing material No. 38 is No. 38. Although the sound absorption performance is about the same as that of No. 3, the mass of the molded product is No. 3. Compared to 3, the molded product is very large. Therefore, the sound absorbing material of the present invention is lighter than before, and when the position where the sound absorbing material is laminated with the porous sheet is arranged at a position of 6/10 to 9/10 of the entire thickness when viewed from the sound source side, the medium frequency is obtained. It can be seen that the sound absorbing performance improves stably over the entire medium frequency to high frequency without being biased to the specific frequency described above.

Example 5
To a fiber web composed of 60% by mass of kenaf fiber, 25% by mass of polyester fiber, and 15% by mass of low-melting polyester fiber (melting point: 140 ° C.), 25% of a sulfomethylated phenol-alkylresorcin-formaldehyde initial cocondensate resin aqueous solution is added to the fiber. After spray coating so that the coating amount was mass%, the resin was heated to 150 ° C. to obtain a B state, and a porous sheet (2E) having a thickness of 15 mm and a basis weight of 150 g / m ² was obtained.
Similarly, a porous sheet (2F) having a thickness of 5 mm and a basis weight of 50 g / m ² was obtained.
Next, the raw material pulp made of wood pulp is JIS P 8121-1995 by a disc refiner. Paper (3E) (airflow resistance: 0.087 kPa · s / m, basis weight 16 g / m ² ) having a shopper freeness of 18 ° SR specified in the shopper freeness test method is applied to the porous sheet ( 2E), an acrylic emulsion was applied as a solid content at a coating amount of 30 g / m ² , and the air flow resistance of the polymer sheet after drying was adjusted to 0.698 kPa · s / m. Further, the above porous sheet (2F) is polymerized thereon and molded into a predetermined shape at 200 ° C. to form a molded sound absorbing material No. 4 was obtained.

  This molded sound absorbing material No. No. 4 differs depending on the molded part, but the thickness was 12 to 18 mm and the ventilation resistance was in the range of about 0.850 to 1.147 kPa · s / m, and it was lightweight and had good sound absorption performance. This molded sound absorbing material No. 4 is arranged such that the porous sheet (2E) comes to the noise source side, and is useful for automobile hood silencers, dash silencers, engine under cover silencers, fender liner silencers, cowl side silencers, cylinder head cover silencers, and the like.

  The sound-absorbing material of the present invention is lightweight and excellent in sound-absorbing performance, and is particularly useful as an automobile interior material, so that it can be used industrially.

It is explanatory drawing explaining protrusion height h. It is explanatory drawing explaining the measuring method of ventilation resistance R. FIG. It is a figure which shows the arrangement configuration of a shaping | molding sound-absorbing material. Sound absorbing material No. 1, no. It is a graph which shows the sound absorption rate with respect to the frequency of 2. FIG. Sound absorbing material No. 11, no. 12, no. It is a graph which shows the sound absorption rate with respect to the frequency of 13. Sound absorbing material No. 22, no. 23, no. 32, no. It is a graph which shows the sound absorption rate with respect to the frequency of 33. Sound absorbing material No. 21, no. 24, no. It is a graph which shows the sound absorption factor with respect to the frequency of 25. Sound absorbing material No. 16, no. 26, no. 34, no. 35, no. It is a graph which shows the sound absorption rate with respect to the frequency of 36. It is a figure which shows the arrangement configuration of a shaping | molding sound-absorbing material. Sound absorbing material No. 3, no. 37, no. 38, no. 39, no. It is a graph which shows the sound absorption factor with respect to the frequency of 40.

Explanation of symbols

1 Sound absorbing material 1a Embossed paper 2, 2A, 2B, 2C, 2D, 2E, 2F Porous sheet 3, 3A, 3B, 3C, 3D, 3E Paper p Projection h Projection height

Claims (8)

  4. Degree of beating is JIS P 8121-1995 One or more layers of paper consisting of pulp fibers with a shopper freeness of 15 ° SR to 30 ° SR specified in the shopper freeness test method and having a ventilation resistance of 0.05 to 3.0 kPa · s / m Is a sound-absorbing material inserted into the porous sheet, and the paper inserted into the noise incident surface side is located on the inner side of the porous sheet from 6/10 to 9/10 of the thickness of the porous sheet. Sound-absorbing material characterized by being inserted.   The sound absorbing material according to claim 1, wherein the porous sheet has a thickness of 10 mm or more.   The sound-absorbing material according to claim 1 or 2, wherein the sound-absorbing material has a ventilation resistance of 0.1 to 5.0 kPa · s / m.   The sound absorbing material according to any one of claims 1 to 3, wherein the paper is subjected to creping and / or embossing to form a large number of irregularities on the surface.   The air resistance is adjusted by applying and / or impregnating and / or mixing a synthetic resin and / or a synthetic resin precursor to the paper and / or the porous sheet. The sound absorbing material according to any one of the above.   The sound absorbing material according to any one of claims 1 to 5, wherein the porous sheet is composed of a multilayer of a plurality of unit porous sheets, and the paper is inserted between the unit porous sheets. .   The sound-absorbing material according to claim 6, wherein the paper and the unit porous sheet are bonded by a breathable adhesive layer. The sound absorbing material according to any one of claims 1 to 7, wherein the sound absorbing material is molded into a predetermined shape.