JP2003108146A - Sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorbing material which is light in weight and is excellent in sound absorbing effect and is used for dashboards, hood silencers, etc., of automobiles. SOLUTION: The sound absorbing material 1 is a sound absorbing material 1 consisting of heartwood 2 longitudinally and transversely arrayed with a plurality of recessed parts 3 and covering materials 4 and 5 for covering the heartwood 2, in which the heartwood 2 is manufactured by thermoforming a porous material impregnated with a thermosetting resin composition and thermally curing the material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material used for automobile dashboards, dash outer silencers, hood silencers, engine undercovers and the like.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a sound absorbing material (1A) has been provided in which a core material (2A) made of a porous material such as a fiber layer is covered with a coating material (4A, 5A).

[0003]

The conventional sound absorbing material (1A) has a problem that the sound absorbing property is not sufficient and the weight is large.

[0004]

Means for Solving the Problems As a means for solving the above-mentioned conventional problems, the present invention comprises a core material (2) having a plurality of recesses (3) arranged vertically and horizontally, and the core material (2). Covering material (4,
5) A sound absorbing material (1) consisting of and, wherein the core material (2) is
The sound absorbing material (1) is produced by heat-molding a porous material impregnated with a thermosetting resin composition and heat-curing the porous material.

The thermoplastic resin composition is preferably a composition comprising a mixture of a phenol resin and an epoxy compound, and further, a part or all of the phenol resin is sulfomethylated and / or sulfimethylated. Is desirable. Further, the porous material is preferably a urethane resin foam.

[0006]

[Function] In the sound absorbing material (1) of the present invention, since the core material (2) is porous, the core material (2) itself has a sound absorbing property.
Since a plurality of them are arranged vertically and horizontally, the sound wave incident on the recess (3) is absorbed by the inner wall of the recess (3) as it is reflected and absorbed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the sound absorbing material (1) of the present invention is
As shown in FIGS. 1 to 4, a core material (2) having a plurality of rectangular box-shaped recesses (3) arranged vertically and horizontally, and a covering material (4,5) for covering the core material (2). Consists of. [Core material] As described above, a porous material impregnated with a thermosetting resin composition is heat-molded and heat-cured, and a plurality of rectangular box-shaped recesses (3) are formed vertically and horizontally to form a core material. (2) is manufactured.

[Porous Material] Examples of the porous material used in the present invention include plastic foams, fiber aggregates and the like. The plastic foam used in the present invention is a plastic foam having an open cell structure,
For example, urethane foam, polyolefin foam such as polyethylene and polypropylene, polyvinyl chloride foam,
Examples include polystyrene foam, amino resin foam such as melamine resin and urea resin, and phenol resin foam. The fiber aggregate used in the present invention, a web, a non-woven fabric,
Felts, knitted fabrics, laminates thereof, and the like, and as the fibers constituting the fiber assembly, natural fibers such as cotton, hemp, wool, silk, kenaf, coconut fibers, and bamboo fibers, polyamide fibers, polyester fibers, Organic synthetic fibers such as acrylic fiber, viscose fiber, acetate fiber, vinyl chloride fiber, vinylidene chloride fiber, asbestos fiber, glass fiber,
Inorganic fibers such as carbon fibers, ceramic fibers, metal fibers, whiskers, rock wool, etc., or recycled fibers obtained by defibrating scraps of fiber products using the above fibers, or two types of these fibers. The above-mentioned mixture, or a mixture of these fibers and low-melting-point fibers such as polyester fibers, polypropylene fibers, polyethylene fibers, and polyamide fibers having a melting point of 200 ° C. or less can be used.

[Thermosetting Resin Composition] Examples of the thermosetting resin composition used in the present invention include thermosetting urethane resin, melamine resin, thermosetting acrylic resin, urea resin, phenol resin, and epoxy resin. There are compositions made of thermosetting resins such as resins and thermosetting polyesters. In the present invention, it is particularly preferable to use a composition comprising a mixture of a phenol resin and an epoxy compound as the thermosetting resin composition, and the phenol resin is preferably water-soluble. The thermosetting resin composition of the present invention includes, for example, a thermosetting resin composition comprising an aqueous phenol resin solution and an epoxy compound dispersed or dissolved in the aqueous phenol resin solution. Less than,
The thermosetting resin composition will be described.

[Phenolic Resin] A phenolic resin is obtained by condensing a phenolic compound with an aldehyde and / or an aldehyde donor. As the water-soluble phenolic resin, it is preferable to use a sulfoalkylated and / or sulfialkylated phenolic resin for improving stability. The present invention is not limited to the phenolic resin, for example, m
A novolac resin obtained by subjecting a cresol composed of -cresol and p-cresol to a carbonyl compound and condensation reaction (JP-A No. 11-322874) can also be used as the water-soluble phenol resin.

(Phenolic Compound) The phenolic compound used in the above phenol resin may be a monohydric phenol or a polyhydric phenol, or a monohydric phenol and a polyhydric phenol. A mixture may be used, but when only monohydric phenol is used, formaldehyde is easily released during and after curing, and therefore polyhydric phenol or a mixture of monohydric phenol and polyhydric phenol is preferably used.

(Monohydric Phenol) Examples of the monohydric phenol include phenol, o-cresol, m-cresol, p-cresol, ethylphenol, isopropylphenol, xylenol, 3,5-xylenol, butylphenol, t-butylphenol, Alkylphenol such as nonylphenol, o-fluorophenol, m-fluorophenol, p-fluorophenol, o-chlorophenol, m-chlorophenol, p
-Chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, o-iodophenol, m-iodophenol, p-iodophenol, o-aminophenol, m-aminophenol, p
-Substituted monohydric phenols such as aminophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, polycyclic ones such as naphthol Examples of the monohydric phenol include these monohydric phenols, which may be used alone or in admixture of two or more.

(Polyhydric Phenol) Examples of the polyhydric phenol include resorcin, alkylresorcin, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol, dihydroxynaphthalene, and the like. Alternatively, two or more kinds can be mixed and used. Among the polyhydric phenols, preferred is resorcin or alkylresorcin, and particularly preferred is alkylresorcin, which has a faster reaction rate with aldehyde than resorcin.

Examples of the alkylresorcin include 5-
Methylresorcin, 5-ethylresorcin, 5-propylresorcin, 5-n-butylresorcin, 4,5-dimethylresorcin, 2,5-dimethylresorcin, 4,
5-diethylresorcin, 2,5-diethylresorcin, 4,5-dipropylresorcin, 2,5-dipropylresorcin, 4-methyl-5-ethylresorcin, 2
-Methyl-5-ethylresorcin, 2-methyl-5-propylresorcin, 2,4,5-trimethylresorcin, 2,4,5-triethylresorcin, and the like. The polyhydric phenol mixture obtained by dry distillation of Estonian oil shale is inexpensive, and contains a large amount of highly reactive alkylresorcin in addition to 5-methylresorcin, and is therefore a particularly preferable polyhydric phenol raw material in the present invention.

In the present invention, the above-mentioned phenolic compound is condensed with an aldehyde and / or an aldehyde donor (aldehydes), and the above-mentioned aldehyde donor means a compound or a mixture thereof which forms and provides an aldehyde when decomposed. Such aldehydes include formaldehyde, acetaldehyde, propionaldehyde, chloral, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allyl aldehyde, benzaldehyde, crotonaldehyde,
Examples thereof include acrolein, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde and the like, and examples of the aldehyde donor include paraformaldehyde, trioxane, hexamethylenetetramine, tetraoxymethylene and the like.

In order to improve the stability of the water-soluble phenolic resin as described above, it is desirable to sulfoalkylate and / or sulfialkylate the phenolic resin.

(Sulfoalkylating Agent) Examples of the sulfoalkylating agent that can be used to improve the stability of the water-soluble phenolic resin include sulfite, bisulfite or metabisulfite, alkali metal, trimethylamine or benzyltrimethylammonium. Examples thereof include water-soluble sulfites obtained by reacting a quaternary amine or a quaternary ammonium, and aldehyde adducts obtained by reacting these water-soluble sulfites with aldehydes. The aldehyde adducts include formaldehyde, acetaldehyde, propionaldehyde, chloral, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, etc. Is added to the water-soluble sulfite, and the aldehyde adduct consisting of formaldehyde and sulfite is hydroxymethanesulfonate.

(Sulfialkylating Agent) As the sulfialkylating agent which can be used to improve the stability of the water-soluble phenolic resin, aliphatic sulfites such as formaldehyde sodium sulfoxylate (Rongalit) and benzaldehyde sodium sulfoxylate are used. Alkali metal sulfoxylates of aromatic aldehydes, sodium hydrosulfite, magnesium hydrosulfite, and other alkali metals, alkaline earth metal hydrosulfites (dithionates), hydroxymethanesulfinate, hydroxy Examples include alkanesulfinate and the like.

(Third component) In the production of the above-mentioned phenol resin, if necessary, for example, hydrochloric acid, sulfuric acid, orthophosphoric acid, boric acid, oxalic acid, formic acid, acetic acid, butyric acid, benzenesulfonic acid,
Inorganic or organic acids such as phenolsulfonic acid, paratoluenesulfonic acid, naphthalene-α-sulfonic acid, naphthalene-β-sulfonic acid, esters of organic acids such as oxalic acid dimethyl ester, maleic anhydride, phthalic anhydride, etc. Acid anhydride, ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium oxalate, ammonium acetate, ammonium phosphate, ammonium thiocyanate, ammonium imidosulfonate, etc., monochloroacetic acid or its sodium salt, α, α'-dichlorohydrin, etc. Organic halides, triethanolamine hydrochloride, amine hydrochlorides such as aniline hydrochloride, urea adducts such as salicylate urea adduct, stearic acid urea adduct, heptanoic acid urea adduct, N-trimethyltaurine, zinc chloride, chloride 2 Oxidation of acidic substances such as iron, ammonia, amines, hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, barium hydroxide and calcium hydroxide, alkaline earth metals such as lime Substances, alkaline substances such as weak salts of alkali metals such as sodium carbonate, sodium sulfite, sodium acetate, sodium phosphate and the like may be mixed as a catalyst or a pH adjuster.

(Production of Phenolic Resin) The above-mentioned phenolic resin (initial condensate) can be produced by a conventional method,
Specifically, (a) a method of condensing a monohydric phenol and / or a polyhydric phenol with an aldehyde, (b) an initial condensate obtained by condensing a monohydric phenol with an aldehyde, and / or a polyhydric phenol An initial condensate obtained by condensing an aldehyde with a monohydric phenol and / or a polyphenol, (c) an initial condensate obtained by condensing a monohydric phenol, a polyhydric phenol and an aldehyde, A method of condensing a monohydric phenol and / or a polyhydric phenol, (d) an initial condensate obtained by condensing a monohydric phenol with an aldehyde, and an initial condensate obtained by condensing a polyhydric phenol with an aldehyde A method of condensing,
(e) An initial condensate obtained by condensing a monohydric phenol and an aldehyde and / or an initial condensate obtained by condensing a polyhydric phenol and an aldehyde, and a monohydric phenol, a polyhydric phenol and an aldehyde are condensed. It can be produced by a method such as condensation with the initial condensate.

For example, the above (a) monohydric phenol and / or
Or, in the condensation of polyhydric phenol and aldehydes, usually 0.2 to 10 aldehydes per mol of monohydric phenol.
3 mol, 1 mol of polyhydric phenol, 0.1 to 0.8 mol of aldehydes, and if necessary, a solvent and a third component are added, and the mixture is heated at a liquid temperature of 55 to 100 ° C. for 8 to 20 hours. Let At this time, all of the aldehydes may be added at the start of the reaction, divided additions or continuous dripping.

The phenolic resin obtained by the condensation reaction of the above phenolic compound with an aldehyde and / or an aldehyde donor may be either a novolac type or a resol type phenolic resin. Considering to prepare as
It is preferably a resol type phenol resin.

When the above-mentioned phenol resin precondensate is sulfoalkylated and / or sulfialkylated,
A sulfoalkylating agent and / or a sulfialkylating agent is added to the precondensate at any stage to sulfoalkylate and / or sulfialkylate the phenolic compound and / or the precondensate. The addition of the sulfoalkylating agent and / or the sulfialkylating agent is
It may be carried out at any stage before, during, or after the condensation reaction.

The total amount of the sulfoalkylating agent and / or the sulfialkylating agent added is usually 0.001 to 1.5 mol per mol of the phenol compound. 0.
When the amount is 001 mol or less, the hydrophilicity of the phenol resin is insufficient, and when the amount is 1.5 mol or more, the water resistance of the phenol resin becomes poor. In order to maintain good properties such as the curability of the initial condensate to be produced and the physical properties of the resin after curing, 0.
The amount is preferably about 01 to 0.8 mol.

The sulfoalkylating agent and / or sulfialkylating agent added to sulfoalkylate and / or sulfialkylate the precondensate is a methylol group of the precondensate and / or the precondensate. A sulfoalkyl group and / or a sulfialkyl group are introduced into the precondensate by reacting with the aromatic ring of the product.

Thus sulfoalkylation and / or
Alternatively, the aqueous solution of the initial condensation product of the sulfialkylated phenol resin is stable in a wide range of acidity (pH 1.0) to alkaline and can be cured in any of the acidic, neutral and alkaline regions. In particular, when cured on the acidic side, residual methylol groups are reduced, and there is no risk of the cured product decomposing and generating formaldehyde.
Even when the epoxy compound used in the present invention is water-insoluble, the water-insoluble epoxy compound is mixed with the aqueous solution of the initial condensate of the sulfomethylated and / or sulfimethylated phenolic resin to give the water-insoluble epoxy compound. It has the advantage that it can be easily dispersed in water and a stable epoxy compound dispersion can be obtained.

Further, in the present invention, as the above-mentioned phenol resin, if desired, urea, thiourea, melamine, thiomelamine, dicyandiamine, guanidine, guanamine, acetoguanamine, benzoguanamine, 2,6 diamino-, etc.
An amino resin monomer of 1,3-diamine and / or an initial condensation product of the amino resin monomer may be added for cocondensation with the phenol compound and / or the initial condensation product.

[Epoxy Compound] The epoxy compound in the present invention is a compound having at least two epoxy groups in one molecule. Examples of such an epoxy compound include diethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether. , Tripropylene glycol diglycidyl ether,
Polypropylene glycol diglycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ester, fatty acid Polyepoxy compounds such as modified epoxy, bisphenol A type epoxy resin, tetrabromobisphenol A
Type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol B type epoxy resin, naphthalene type epoxy resin, novolac type epoxy resin, epoxy resin having fluorene skeleton,
Epoxy resins made from a copolymer of a phenol compound and dicyclopentadiene as a raw material, diglycidyl resorcinol type epoxy resins, glycidyl ether type epoxy resins, glycidyl amine type epoxy resins and other epoxy resins, and the polyepoxy compound and The epoxy resins may be used alone or in combination of two or more.

The above-mentioned epoxy compound is preferably water-soluble or water-dispersible in consideration of the easiness of dissolution and dispersion in the phenol resin aqueous solution, the homogeneity of the mixture, and the like. It is preferable to emulsify with a surfactant and then mix with the phenol resin aqueous solution. However, even a water-insoluble epoxy compound can be dissolved or emulsified by dissolving a surfactant in an aqueous solution of a phenol resin as it is or in an organic solvent. And / or sulfialkylated, since the phenolic resin itself acts as a dispersant, even if the epoxy compound is water-insoluble, it can be dispersed and emulsified without using a surfactant. . When an epoxy resin is used as the epoxy compound, the resin composition of the present invention gives a cured product having high strength. In this case, when the epoxy resin has an aromatic ring, a part or the whole thereof may be sulfoalkylated and / or sulfialkylated in the same manner as the phenol resin to improve the affinity for water. In this case, the sulfoalkylating agent and / or the sulfialkylating agent is 0.00 relative to the epoxy resin monomer such as bisphenol.
The amount is 1 to 1.5 mol, preferably about 0.01 to 0.8 mol. When it is less than 0.001 mol, the hydrophilicity of the epoxy resin is not sufficient, and when it is more than 1.5 mol, the water resistance of the epoxy resin is deteriorated.

One or more monoepoxy compounds may be added to the above epoxy compound for the purpose of improving flexibility and reactive diluent. Examples of such monoepoxy compounds include higher alcohol glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, nonylphenyl glycidyl ether, and glycidyl methacrylate.

The compounding amount of the epoxy compound with respect to 100 parts by weight of the phenol resin is preferably 2 to 150 parts by weight as a solid content, and particularly preferably 5 to 100 parts by weight. If the compounding amount of the epoxy compound is less than 2 parts by weight, the phenol resin is not sufficiently cured, and if the compounding amount of the epoxy compound exceeds 150 parts by weight, the amount of the epoxy compound that does not bond with the phenol resin increases and the strength is adversely affected. Exert. The resin composition is usually provided as an aqueous solution of an initial condensate.

In the resin composition of the present invention, if necessary, ethylenediamine, diethylenetriamine, triethylenetetramine, dipropylenetriamine, dimethylaminopropylamine, diethylaminopropylamine, cyclohexylaminopropylamine, monoethanolamine, diethanolamine, propanol. Amines, aliphatic amines such as N-methylethanolamine, aminoethylethanolamine, methanephenylenediamine, P, P'-diaminodiphenylmethane, diaminodiphenylsulfone, benzyldimethylamine, α-methyldimethylamine, dimethylaminomethylphenol,
Amine such as aromatic amine such as tridimethylaminomethylbenzene, phthalic anhydride, hexahydrophthalic hydride, dodecyl succinic hydride, pyromeric dianhydride, chlorentic hydride and other acid anhydrides Epoxy resin curing agent; formaldehyde, acetaldehyde, propionaldehyde, chloral, furfural, glyoxal, n-butyraldehyde, caproaldehyde,
Allyl aldehyde, benzaldehyde, crotonaldehyde, acrolein, phenylacetaldehyde, o-
Aldehydes such as tolaldehyde and salicylaldehyde,
Aldehydes such as aldehyde donors such as paraformaldehyde, trioxane, hexamethylenetetramine and tetraoxymethylene; amino resins such as urea resins and melamine resins; natural rubber or its derivatives; styrene-
Butadiene rubber, acrylonitrile-butadiene rubber,
Synthetic rubbers such as chloroprene rubber, ethylene-propylene rubber, isoprene rubber, isoprene-isobutylene rubber; vinyl acetate, vinyl propionate, styrene, acrylic ester, methacrylic ester, acrylonitrile, acrylic acid, methacrylic acid, maleic acid, vinyl chloride, chloride Homopolymers of vinyl monomers such as vinylidene and vinyl pyridine, or copolymers of two or more kinds of these vinyl monomers; polyurethane, polyamide, butyral resin,
Emulsion, latex or aqueous solution of various synthetic resins such as polyethylene, polypropylene, vinyl acetate-ethylene copolymer, chlorinated polyethylene, chlorinated polypropylene, polyester; polyvinyl alcohol, sodium alginate, starch, starch derivative, glue, gelatin, blood powder, Water-soluble polymers and natural gums such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid salt, polyacrylamide; calcium carbonate, talc, gypsum, carbon black, wood flour, walnut flour, coconut husk flour, wheat flour, rice flour, etc. Fillers; surfactants; higher fatty acids such as stearic acid and palmitic acid; higher alcohols such as palmityl alcohol and stearyl alcohol; butyryl stearate, glycerin monostearate and other fats Esters of acids; fatty acid amides; natural waxes such as carnauba wax; synthetic waxes; paraffins, paraffin oil, silicone oil, silicone resins, fluororesins, polyvinyl alcohol, mold release agents such as grease; hexane, butane, n-pentane, alcohol, ether, methylene chloride, carbon tetrachloride, chlorofluoromethane, 1,1,2-trichloro-
Low boiling point solvents such as 1,2,2-trifluoroethane; azodicarbonamide, dinitrosopentamethylenetetramine, P, P'-oxybis (benzenesulfonylhydrazide), azobis-2,2 '-(2-methylgulos) Pionitrile) and other organic foaming agents; sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate and other inorganic foaming agents; n-pentane, isopentane, butane, isobutane, etc. encapsulated in thermoplastic resin microcapsules Agents: hollow particles such as shirasu balloon, perlite, glass balloon, foam glass, hollow ceramics; plastic foams and expanded particles such as expanded polyethylene, expanded polystyrene, expanded polypropylene; pigments, dyes, flame retardants, flame retardants, and repellents Water solution, oil repellent, insect repellent, antiseptic, antiaging agent, ultraviolet absorber; D The above-mentioned phenol resin and / or epoxy compound is prepared by adding a third component such as a phthalic acid ester plasticizer such as P, DOP or dicyclohexyl phthalate, or another plasticizer such as tricresyl phosphate, and by cocondensation or mixing. May be modified.

Core material used for the sound absorbing material (1) of the present invention
(2) is usually to impregnate the porous material with the thermosetting resin composition, and heat-dry at a temperature not higher than the curing temperature of the thermosetting resin composition to obtain a molding material, It is manufactured by hot pressing using a molding machine composed of a lower mold and an upper mold having a mold surface shape.

As a method of impregnating the porous material with the thermosetting resin composition, a known method such as a dipping method or a spray method is applied. In the case of the dipping method, for example, by immersing the porous material in an impregnation tank filled with the resin composition, and then pressing the porous material to which the resin composition adheres with a squeezing roll or a press platen, The porous material can be impregnated with a predetermined amount of the resin composition. The resin composition filled in the impregnation tank may be foamed and / or foamed. The amount of the resin composition impregnated in the core material (2) is 5 to 200% by weight as the solid content of the resin composition.

The porous material impregnated with the resin composition as described above is subjected to a heating and drying step to become a molding material. In this step, the resin composition with which the porous material is impregnated may be in the B state. In order to keep the resin composition in the B state, the heating temperature, the heating time and the like may be adjusted, and the heating temperature is set to the curing temperature of the resin composition or lower. For example, when a composition comprising a mixture of an aqueous phenol resin solution and an epoxy compound is used as the curable resin composition, it is usually 50 to 180 ° C., and the heating time is about 0.1 to 5 hours. For the heating and drying, hot air drying, far infrared ray drying, high frequency heating and drying, etc. are usually applied.

The molding material obtained as described above is hot-pressed to manufacture a plurality of rectangular box-shaped core materials (2) arranged vertically and horizontally. The molding machine used for hot pressing has a lower mold and an upper mold having a desired mold surface shape, and for forming the shape of the recess (3) of the core material (2) on the upper mold. A plurality of rectangular convex portions are arranged vertically and horizontally. The conditions for the hot pressing are set to a temperature and a time at which the thermosetting resin is completely cured, and the pressing pressure is usually 1 to 10 kg / cm ² .

The shape of the recess (3) formed in the core material (2) is
The shape is not limited to the rectangular box shape shown in FIG.
It may have a circular hole shape such as the concave portion (13) of the core material (12) shown in FIG. The total area of the recesses (3) with respect to the surface area of the core material (2) (core material
(2) The ratio of the cross-sectional areas of the plurality of recesses (3) formed on the surface is preferably in the range of 50:50 to 5:95.

[Coating Material] Core material obtained as described above
The sound absorbing material (1) is obtained by covering the upper and lower sides of (2) with the covering materials (4,5).

The coating material (4,5) is a non-woven fabric made of synthetic fibers such as polyamide fiber, polyester fiber, polyolefin fiber, acrylic fiber, vinyl chloride fiber and vinylidene chloride fiber, and natural fibers such as cotton, hemp and wool. knitted fabrics, and the synthetic consists resin resin films and sheets such as material, usually a basis weight 15g / m ² ~200g / m ² about what is used, the coating material (4, 5) is non-woven or knitted fabric In some cases, it may be impregnated with a synthetic resin. The synthetic resin used as the material of the coating material (4,5) is a known synthetic resin, for example, polyolefin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, chloride, etc. Vinyl resin, styrene resin, acrylic resin, methacrylate resin, vinylidene chloride resin, vinyl propionate resin, styrene-butadiene copolymer, thermoplastic polyester resin, thermoplastic polyamide resin, acrylonitrile-butadiene- Styrene copolymer (ABS), acrylonitrile-chlorinated polyethylene-styrene copolymer (ACS), acrylonitrile-butadiene-styrene-N-phenylmaleimide copolymer, polyethylene naphthalate (PEN) resin, polyethylene terephthalate (PET) resin Polybutylene terephthalate (PB
T) resin, polytrimethylene terephthalate (PTT)
Resin, isophthalic acid or 1,4-cyclohexanedimethanol modified (A-PET), polycarbonate (P
C), polyester (PE), polysulfone (PS
F), polyether sulfone (PES), polyphenylene ether (PPE), polyether ether ketone (PEEK), polyamideimide (PAI), polyetherimide (PEI), methylpentene copolymer (T
PX), polyphenylene ether (PPE), cellulose acetate (CA), polyimide (PI), polyallyl ester (PAE), polyarylate (PAR), polyvinyl fluoride (PVF), polyvinylidene fluoride (P).
VDF), liquid crystal type such as polyallyl ether, fluororesin (polytetrafluoroethylene), amorphous polymer, aminobimaleimide, styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS) , Styrene-ethylene-
Butylene-styrene copolymer (SEBS), styrene-
Ethylene-propylene-styrene copolymer (SEP
S), styrene-maleic anhydride copolymer, styrene-
Acrylonitrile copolymer, acrylonitrile-styrene-acrylic acid ester copolymer, methyl methacrylate-butadiene-styrene copolymer, syndiotactic polystyrene (S
PS), polyacetal (POM), acrylic rubber-acrylonitrile-styrene copolymer (AAS), acrylonitrile-ethylene / propylene rubber-styrene copolymer (AES), metallocene polypropylene, metallocene polyethylene, methyl methacrylate-butadiene-
Styrene copolymer (MBS), polyamide, polycarbonate, polyester, polyphenylene sulfide (P
PS), polyphenylene sulfone (PPSU), engineering plastics such as methylpentene copolymer, and the like.

[Sound Absorbing Material] The sound absorbing material of the present invention is obtained by coating the core material (2) above and below with the coating material (4,5).
(1) is manufactured. Usually the upper and lower covering materials (4,5) are core materials (2)
Are overlapped around and fixed by adhesion, sewing, etc. A normal adhesive or a hot melt adhesive is used for adhesion.

The core material (2) of the sound absorbing material (1) is formed by impregnating a porous material with a thermosetting resin and then forming the concave portion (3). The core material (22) may be made of a porous material in which the recesses (3) have been formed in advance before the resin is impregnated. In this case, the recesses (23) formed in the core material (22) are As shown in FIG. 6, it may have a shape penetrating the core material (22).

The sound absorbing material of the present invention will be described below with reference to examples.
(1) will be explained. However, the present invention is not limited to the examples shown below. (Example) A urethane resin foam as a porous material, a core material using a composition comprising a mixture of an aqueous phenol resin solution and an epoxy compound as a thermosetting resin composition (2)
Was manufactured. In order to obtain the core material (2), the urethane resin foam is immersed in a dipping tank filled with the above resin composition, pressed by a roll to impregnate a predetermined amount of the resin composition, and the resin composition is heated. In the drying step, the molding material was obtained in the B state. The various conditions of the heating and drying step are as follows: 120 ° C. while sucking the molding material impregnated with the resin composition from the lower surface,
Allow to dry for minutes. The obtained molding material was hot-press molded to obtain a core material (2) having a plurality of rectangular box-shaped recesses (3) shown in FIG. The various conditions in hot press molding were a heating temperature of 180 ° C., a heating time of 60 seconds, and a pressing pressure of 10 kg / cm ² . The recess (3) provided in the core (2) is in the shape of a rectangular box as shown in FIG. 3, and the surface area of the core (2) and the recess
The ratio with the area of the upper end surface of (3) is 15:85. Polyester fiber non-woven fabric (Basis weight 40 g / m
² ) The sound absorbing material (1) was obtained by coating the covering material (4,5).

[Sound Absorption Test] The sound absorption material (1) manufactured in the above-mentioned example was subjected to a sound absorption test. The height h ₁ of the sound absorbing material (1) is 20 mm, and the upper surface of the recess (3) L ₁ × L ₂ = 5 mm ×
The height of the concave portion (3) is 5 mm, and the height h ₂ is 15 mm. 800H
Waveforms having frequencies of z, 1500 Hz and 2000 Hz were irradiated from the upper surface of the sound absorbing material (1), and the sound absorbing efficiency (%) was measured on the lower surface of the sound absorbing material (1). Sound absorption efficiency (%) at each frequency is 85% (800 Hz), 98% (15
It was confirmed that the sound absorbing material (1) had a good sound absorbing efficiency, which was 00 Hz) and 95% (2000 Hz).

(Comparative Example) As a comparative example of the sound absorbing material (1), a urethane resin foam having no recessed portion is used as a core material, and the core material is a polyester fiber which is a coating material of the sound absorbing material (1). A sound absorption test of the sound absorbing material coated with a non-woven fabric (unit weight: 40 g / m ² ) was performed. The shape of the core material is the same as that of the sound absorbing material (1) except that the recess is not formed. Sound absorption efficiency (%) under the same conditions as in the above example
Was measured. Sound absorption efficiency (%) at each frequency of the comparative example
Are 60% (800 Hz), 78% (1500 Hz) and 74% (2000 Hz), and the sound absorbing material (1) of the comparative example is inferior in sound absorbing efficiency (%). all right.

[0045]

INDUSTRIAL APPLICABILITY The present invention provides a sound absorbing material which is lightweight and has a large sound absorbing effect.

[Brief description of drawings]

FIG. 1 Perspective view of sound absorbing material

FIG. 2 is a partial perspective view of the sound absorbing material, showing an AA cross section of the sound absorbing material.

FIG. 3 is a perspective view of a core material having a rectangular box-shaped recess.

FIG. 4 is a partial perspective view of the core material, showing a BB cross section of the core material of FIG. 3;

FIG. 5 is a perspective view of a core material having a circular hole-shaped recess.

FIG. 6 is a partial perspective view of a core material having a recess in which the height of the core material is equal to the height of the recess.

FIG. 7 is a perspective view of a conventional sound absorbing material.

[Explanation of symbols]

1 Sound absorbing material 2,12,22 core material 3, 13, 23 recess 4,5 coating material

Claims (4)

[Claims] 1. A sound-absorbing material comprising a core material having a plurality of recesses arranged vertically and horizontally, and a covering material for covering the core material, wherein the core material is impregnated with a thermosetting resin composition. A sound-absorbing material produced by heat-molding a porous material and thermosetting it. 2. The sound absorbing material according to claim 1, wherein the thermoplastic resin composition is a composition comprising a mixture of a phenol resin and an epoxy compound. 3. The sound absorbing material according to claim 2, wherein a part or all of the phenol resin is sulfomethylated and / or sulfimethylated. 4. The sound absorbing material according to claim 1, wherein the porous material is a urethane resin foam.