Sound absorbing material

Abstract

To provide a sound absorbing material in which a nonwoven fabric is laminated on a polyurethane foam, which exhibits little deterioration in sound absorption even in the mid-frequency range and beyond, and has good sound absorption properties. The sound-absorbing material (10) is made by laminating a nonwoven fabric (21) on a polyurethane foam (11) obtained from a polyurethane foam raw material containing polyol, isocyanate, a blowing agent, and a catalyst. The polyurethane foam raw material contains sodium bicarbonate and an organic solid acid. The nonwoven fabric (21) has a basis weight of 2 to 200 g / m. 2 The average fiber diameter is preferably 0.5 to 20 μm. Examples of the organic solid acid include citric acid, fumaric acid, malonic acid, stearic acid, pyruvic acid, phthalic acid, malic acid, maleic acid, and succinic acid.

Description

[Technical field]

[0001] The present invention relates to a sound-absorbing material having good sound-absorbing properties even in the high frequency range. [Background technology]

[0002] Conventionally, there is a sound-absorbing material in which nonwoven fabric is laminated onto polyurethane foam in order to improve sound absorption in the mid-frequency range (2000 to 3150 Hz). Polyurethane foam is obtained by foaming a polyurethane foam raw material containing a polyol, an isocyanate, a blowing agent, and a catalyst. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3388681 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional sound-absorbing materials made of a laminate of polyurethane foam and nonwoven fabric have a problem in that their sound-absorbing properties peak in the mid-frequency range and then decrease in the high-frequency range. The present invention has been made in consideration of the above-mentioned points, and aims to provide a sound-absorbing material in which a nonwoven fabric is laminated to a polyurethane foam, which exhibits little deterioration in sound absorption properties even in the mid-frequency range and beyond, and which provides good sound absorption properties. [Means for solving the problem]

[0005] First aspect The sound-absorbing material is formed by laminating a nonwoven fabric to a polyurethane foam obtained from a polyurethane foam raw material containing a polyol, an isocyanate, a blowing agent, and a catalyst, and is characterized in that the polyurethane foam raw material contains sodium bicarbonate and an organic solid acid.

[0006] Second Aspect teeth, First aspect The nonwoven fabric has a basis weight of 2 to 200 g / m 2 The average fiber diameter is 0.5 to 20 μm.

[0007] Third aspect teeth, First aspect or Second Aspect The nonwoven fabric is bonded to the polyurethane foam via an adhesive layer.

[0008] Fourth aspect The invention is Third aspect The adhesive layer is characterized in that it is made of a layer of adhesive applied to one or both of the polyurethane foam and the nonwoven fabric to an extent that breathability can be ensured.

[0009] Fifth aspect teeth, First aspect from Fourth aspect Either one of t The nonwoven fabric is characterized in that it is a nonwoven fabric spun by a melt-blowing method.

[0010] Sixth Aspect The invention is First aspect or Second Aspect The nonwoven fabric is formed on the surface of the polyurethane foam by spinning using a melt-blowing method. Effect of the Invention

[0011] According to the present invention, in a sound-absorbing material in which a nonwoven fabric is laminated to a polyurethane foam, the polyurethane foam raw material contains sodium bicarbonate and an organic solid acid, so that a sound-absorbing material with good sound-absorbing properties is obtained with little deterioration in sound-absorbing properties even in the mid-frequency range and beyond. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of a sound-absorbing material according to one embodiment of the present invention. [Diagram 2]FIG. 1 is a diagram showing an endothermic reaction between sodium bicarbonate and citric acid. [Diagram 3] FIG. 1 is a diagram showing an endothermic reaction between sodium bicarbonate and malic acid. [Figure 4] 1 is a table showing the formulations of polyurethane foams and the results of measuring physical properties in the comparative examples and examples. [Diagram 5] 1 is a table showing the measurement results of normal incidence sound absorption coefficients of Examples and Comparative Examples. [Figure 6] 1 is a table showing the measurement results of the sound absorption coefficient in a reverberation room of an embodiment and a reference example. [Figure 7] 1 is a table showing the measurement results of the sound absorption coefficient in a reverberation room of an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A sound absorbing material 10 according to one embodiment of the present invention shown in FIG. 1 has a polyurethane foam 11 and a nonwoven fabric 21 laminated thereon. Polyurethane foam 11 is produced by mixing and reacting polyurethane foam raw materials including polyol, isocyanate, a blowing agent, a catalyst, sodium bicarbonate, and an organic solid acid.

[0014] As the polyol, a polyol for polyurethane foam can be used. For example, any of polyether polyol, polyester polyol, polyether ester polyol, etc. may be used, and one or more of these may be used.

[0015] Examples of polyether polyols include polyether polyols obtained by adding alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO) to polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose.

[0016] Examples of polyester polyols include polyester polyols obtained by polycondensation of an aliphatic carboxylic acid such as malonic acid, succinic acid, or adipic acid, or an aromatic carboxylic acid such as phthalic acid, and an aliphatic glycol such as ethylene glycol, diethylene glycol, or propylene glycol. Examples of the polyether ester polyol include those obtained by reacting the above-mentioned polyether polyol with a polybasic acid to form a polyester, and those having both polyether and polyester segments in one molecule.

[0017] As for the polyol, it is preferable to use one or more polyols having a hydroxyl value (OHV) of 20 to 300 mgKOH / g, a functionality of 2 to 6, and a weight average molecular weight of 500 to 15,000.

[0018] As the isocyanate, an aliphatic or aromatic polyisocyanate having two or more isocyanate groups, a mixture thereof, and a modified polyisocyanate obtained by modifying them can be used. As the aliphatic polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexamethane diisocyanate, etc. can be mentioned, and as the aromatic polyisocyanate, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate, xylylene diisocyanate, polymeric MDI (crude MDI), etc. can be mentioned. In addition, prepolymers can also be used.

[0019] The isocyanate index (INDEX) is preferably 100 or more, and more preferably 100 to 125. The isocyanate index is a value obtained by dividing the number of moles of isocyanate groups in an isocyanate by the total number of moles of active hydrogen groups such as hydroxyl groups in a polyol, and multiplying the result by 100, and is calculated by [NCO equivalent of isocyanate ÷ active hydrogen equivalent × 100].

[0020] The foaming agent is preferably water. When the polyol reacts with the isocyanate, water generates carbon dioxide gas, which causes foaming. The amount of water used as the foaming agent is 10 parts by weight or more relative to 100 parts by weight of the polyol, and the preferred amount of water is 10 to 15 parts by weight.

[0021] The catalyst includes a metal catalyst, which is preferably used in combination with an amine catalyst. Examples of the metal catalyst include tin catalysts such as stannous octoate and dibutyltin dilaurate, phenylmercury propionate, and lead octenate. The amount of the metal catalyst is 0.2 to 0.8 parts by weight, preferably 0.3 to 0.7 parts by weight, and more preferably 0.4 to 0.6 parts by weight, based on 100 parts by weight of the polyol. By including the metal catalyst in the above range, the air permeability of the polyurethane foam can be reduced and the sound absorption can be improved. Examples of the amine catalyst include triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, and tetramethylguanidine. The amount of the amine catalyst is preferably 0 or 0.05 to 0.5 parts by weight based on 100 parts by weight of the polyol.

[0022] The amount of sodium hydrogen carbonate is preferably 5 to 50 parts by weight based on 100 parts by weight of polyol. By setting the amount of sodium hydrogen carbonate within the above range, the endothermic reaction can be carried out well, and the rise in heat generation temperature during the production of polyurethane foam can be suppressed.

[0023] The organic solid acid, when used in combination with sodium bicarbonate, exhibits a greater endothermic effect during the production of polyurethane foam, and can more effectively suppress the rise in heat-generating temperature of the polyurethane foam. The amount of the organic solid acid is preferably 1 / 30 to 1 / 60, more preferably 1 / 30 to 1 / 50, of the amount of sodium bicarbonate.

[0024] Examples of organic solid acids include citric acid, fumaric acid, malonic acid, stearic acid, pyruvic acid, phthalic acid, malic acid, maleic acid, succinic acid, and polybasic carboxylic acids having a hydroxyl group. The organic solid acid is not limited to one type, and two or more types may be used in combination. In particular, citric acid and malic acid (hydroxy acid) are more preferred organic solid acids in the present invention, and either one or both are used. In particular, malic acid is a preferred organic solid acid in the present invention. Note that either hydrate or anhydride of citric acid can be used.

[0025] When the organic solid acid is citric acid, the first-stage endothermic reaction is as shown in Figure 2, where the reaction between sodium bicarbonate and citric acid produces trisodium citrate, water, and carbon dioxide. The heat absorbed during this process suppresses the temperature rise caused by the reaction of the polyurethane foam raw materials.

[0026] Furthermore, sodium bicarbonate that was not consumed in the first-stage endothermic reaction undergoes the second-stage endothermic reaction shown in Figure 2 due to heat generated by the subsequent reaction of the polyurethane foam raw materials, thereby further suppressing the temperature rise due to the reaction of the polyurethane foam raw materials. In the second-stage endothermic reaction, sodium bicarbonate that was not consumed in the first-stage endothermic reaction is thermally decomposed into sodium carbonate, water, and carbon dioxide.

[0027] The first-stage endothermic reaction and the second-stage endothermic reaction when the organic solid acid is malic acid are as shown in FIG. In addition, water and carbon dioxide are generated as the reaction decomposition products of sodium bicarbonate and organic solid acid (e.g., citric acid or malic acid). The water generated evaporates and the carbon dioxide is naturally released from the polyurethane foam, making the polyurethane foam lighter.

[0028] Other auxiliaries may be added to the polyurethane foam raw material. Examples of auxiliaries include foam stabilizers and colorants. As the foam stabilizer, a foam stabilizer known for polyurethane foams can be used. Examples of the foam stabilizer include silicone foam stabilizers, fluorine foam stabilizers, and known surfactants. As the colorant, a carbon pigment or the like can be used depending on the application of the polyurethane foam.

[0029] The polyurethane foam 11 of the present invention has a density (JIS K7220) of 8 to 15 kg / m 3 By making the density low within the above range, the polyurethane foam can be made lightweight. In addition, the polyurethane foam 11 of the present invention has a breathability (JIS K6400-7:2012) of 0.2 to 10 cc / cm 2 / s, and more preferably 0.2 to 5 cc / cm 2 By achieving low air permeability within the above range, the sound absorbing properties of the polyurethane foam can be improved.

[0030] In addition, the thicker the polyurethane foam 11 of the present invention is, the better the sound absorbing property of the sound absorbing material 10 is, but the sound absorbing material 11 becomes bulky and heavy, so the thickness is determined according to the place where the sound absorbing material 11 is used, etc. An example is a thickness of 5 to 50 mm.

[0031] The foaming method for producing polyurethane foam can be a molded foaming method in which the mixture is poured into a metal mold or a slabstock foaming method, of which the slabstock foaming method is preferred for mass production. The slabstock foaming method is a method in which two liquid polyurethane foam raw materials are mixed in a mixer, discharged onto a belt conveyer, and foamed at atmospheric pressure and room temperature. The polyurethane raw material composition can be produced by a one-shot method, a prepolymer method, or the like.

[0032] The nonwoven fabric 21 has a basis weight of 2 to 200 g / m 2The average fiber diameter is preferably 0.5 to 20 μm. By setting the basis weight and average fiber diameter within the above ranges, the sound absorbing properties of the sound absorbing material 10 can be improved.

[0033] The nonwoven fabric is made of olefin fibers, polyester fibers, acrylic fibers, urethane fibers, acetate fibers, rayon fibers, etc. The fibers are produced by melt spinning, dry spinning, dry spinning, etc., and the production method is not limited. The cross section of the fiber may be a single-layer cross section, a multi-layer cross section, a core-sheath cross section, a hollow cross section, a split structure, etc. Ultrafine fibers obtained by a process of splitting the fibers after spinning are also useful. The nonwoven fabric may be obtained by any of the spinning methods of the dry method, the wet method, the spunbond method, the meltblowing method (also called the meltblown method), and the airlaid method. The method of bonding the fibers together may be any of the spinning methods of the chemical bond method, the thermal bond method, the needle punch method, and the spunlace method. In particular, nonwoven fabrics spun by the meltblowing method are preferred. In the melt-blowing spinning method, molten thermoplastic resin is blown out of the fine holes in the die of the extruder with a high-speed, high-temperature air flow into threads, which are then accumulated on a belt conveyer and form a web by the entanglement and fusion of the fibers. The fine holes in the die are formed in the number of several hundred per meter.

[0034] The nonwoven fabric 21 may be bonded to the polyurethane foam 11 via an adhesive layer, or may be formed directly on the surface of the polyurethane foam 11 by a melt-blowing method.

[0035] The adhesive layer is preferably formed of a layer of adhesive applied to one or both of the polyurethane foam 11 and the nonwoven fabric 21 to an extent that breathability can be ensured. An example of a method for ensuring breathability in the adhesive layer is a method in which a liquid adhesive is applied in a scattered manner to one or both of the polyurethane foam 11 and the nonwoven fabric 21 by spraying or the like. An example of the adhesive is a moisture-curing urethane-based hot melt manufactured by Taihei Chemack Co., Ltd., product number 708.1, etc.

[0036] When the nonwoven fabric 21 is formed directly on the surface of the polyurethane foam 11 by the melt-blowing method, the polyurethane foam is fed onto a belt conveyer, and molten thermoplastic resin is blown out of the die of an extruder in the form of threads onto the surface of the polyurethane foam on the belt conveyer, and the threads are accumulated on the surface of the polyurethane foam, forming a web by entanglement and fusion of the fibers. At that time, the web is fused to the surface of the polyurethane foam, and the formed nonwoven fabric is adhered to the surface of the polyurethane foam. EXAMPLES

[0037] The following components were mixed in the ratio shown in Figure 4 and reacted and foamed to produce polyurethane foams of the comparative examples and examples. The unit of the amount of each component added is parts by weight. Polyol: Polyether polyol, molecular weight: 3000, functionality: 3, hydroxyl value: 56.1 mg KOH / mg, product number: GP-3050, manufactured by Sanyo Chemical Industries, Ltd. Foaming agent: water Amine catalyst: N-ethylmorpholine, product code: NEM, manufactured by Huntsman Metal catalyst: Stannous octoate, product number: MRH110, manufactured by Johoku Chemical Industry Co., Ltd. Foam stabilizer: Silicone foam stabilizer, product code: B8110, manufactured by Evonik Sodium bicarbonate Malic Acid Isocyanate: 2,4-TDI / 2,6-TDI=80 / 20, Product No.: Coronate T-80, manufactured by Nippon Polyurethane Industry Co., Ltd.

[0038] The polyurethane foams of the comparative examples and examples were measured for heat generation temperature (maximum heat generation temperature), density (JIS K7220), hardness (JIS K6400-2:2004), and air permeability (JIS K6400-7:2012).

[0039] The polyurethane foam of the comparative example contains 100 parts by weight of polyol, 5.6 parts by weight of blowing agent (water), 0.2 parts by weight of amine catalyst, 0.3 parts by weight of metal catalyst, 1 part by weight of foam stabilizer, 66 parts by weight of isocyanate, and has an isocyanate index of 105, and is an example in which neither sodium bicarbonate nor malic acid (organic solid acid) is added. The polyurethane foam of the comparative example has a heat generation temperature of 159°C and a density of 21.0 kg / m 3 , hardness 98N, ventilation 90cc / cm 2 / s, and the density and breathability were high.

[0040] The polyurethane foam of the example contains 100 parts by weight of polyol, 12 parts by weight of blowing agent (water), 0.2 parts by weight of amine catalyst, 0.5 parts by weight of metal catalyst, 1 part by weight of foam stabilizer, 30 parts by weight of sodium bicarbonate, 0.8 parts by weight of malic acid, 131.2 parts by weight of isocyanate, and an isocyanate index of 105. In the example, the heat generation temperature is 145°C and the density is 10.5 kg / m 3 , hardness 78N, ventilation 0.2cc / cm 2 / s.

[0041] The polyurethane foam of the Example has an increased amount of blowing agent (water) of 12 parts by weight compared to the polyurethane foam of the Comparative Example. Although the heat generation temperature would be higher without any change, the inclusion of both sodium bicarbonate and malic acid resulted in a lower heat generation temperature than the Comparative Example. In addition, the amount of blowing agent (water) of the Example was increased to 12 parts by weight, resulting in a lower density and lower breathability. Due to the low breathability of the polyurethane foam of the Example, it is expected that the sound absorbing material in which nonwoven fabric is laminated to the polyurethane foam of the Example will have good sound absorbing properties.

[0042] The polyurethane foam of the example was cut to a thickness of 20 mm, and a nonwoven fabric was laminated to the polyurethane foam via an adhesive layer to produce the sound absorbing material (PUt20 + nonwoven fabric) of Example 1. The polyurethane foam of the comparative example was cut to a thickness of 20 mm, and a nonwoven fabric was laminated to the polyurethane foam via an adhesive layer to produce the sound absorbing material (PUt20 + nonwoven fabric) of Comparative Example 1. The nonwoven fabric and adhesive layer were the same for the sound absorbing material of Example 1 (PUt20 + nonwoven fabric) and the sound absorbing material of Comparative Example 2 (PUt20 + nonwoven fabric). The nonwoven fabric is a melt-blown nonwoven fabric (propylene), with a basis weight of 20 g / m 2 , average fiber diameter 2.3 μm, product number: MER04, manufactured by Mitsui Chemicals. The adhesive layer was made by applying 20 g / m2 of moisture-curing urethane hot melt adhesive (product number 708.1, manufactured by Taihei Chemack Co., Ltd.) to the surface of the polyurethane foam. 2 was applied in a dot pattern to ensure breathability.

[0043] The normal incidence sound absorption coefficient (in accordance with JIS A1405-2:2007) was measured for the sound absorbing material of Comparative Example 1 (PUt20+nonwoven fabric) and the sound absorbing material of Example 1 (PUt20+nonwoven fabric) in the center frequency range of 500 to 6300 Hz in the 1 / 3 octave band. The normal incidence sound absorption coefficient was measured in accordance with JIS A 1405-2. In the present invention, the evaluation was performed with the ultra-low frequency region being the center frequency of the 1 / 3 octave band (500 to 800 Hz), the low frequency region being (1000 to 1600 Hz), the mid frequency region being (2000 to 3150 Hz), and the high frequency region being (4000 to 6300 Hz).

[0044] The measurement results of the normal incidence sound absorption coefficient are shown in Figure 5. The sound absorbing material of Example 1 (PUt20 + nonwoven fabric) had higher sound absorption properties than the sound absorbing material of Comparative Example 1 (PUt20 + nonwoven fabric) in all ranges from the infrasound frequency range to the high frequency range. In addition, the sound-absorbing material of Example 1 (PUt20 + nonwoven fabric) had almost the same sound absorption coefficient in the mid-frequency region and the high-frequency region, with almost no decrease in sound absorption coefficient, whereas the sound-absorbing material of Comparative Example 1 (PUt20 + nonwoven fabric) had a large decrease in sound absorption coefficient, with the sound absorption coefficient in the high-frequency region decreasing by just under 50% relative to the sound absorption coefficient in the mid-frequency region.

[0045] The sound-absorbing material of Example 1 (PUt20 + nonwoven fabric) uses the same nonwoven fabric as the sound-absorbing material of Comparative Example 1 (PUt20 + nonwoven fabric), but uses a polyurethane foam formed from a polyurethane foam raw material containing both sodium bicarbonate and malic acid (organic solid acid) as a base material. As a result, the sound-absorbing material of Example 1 has higher sound absorption properties than the sound-absorbing material of Comparative Example 1 (PUt20 + nonwoven fabric), and there is almost no decrease in sound absorption rate from the mid-frequency range to the high-frequency range.

[0046] A sound-absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) was produced by laminating two types of nonwoven fabric. The reverberation chamber sound absorption coefficient (in accordance with JIS A 1409) was measured for the sound-absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) and that of Example 1 (PUt20 + nonwoven fabric) by dividing the center frequency range of 500 to 6300 Hz in a 1 / 3 octave band into four frequency regions. The sound-absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) has a base material of polyethylene terephthalate fiber nonwoven fabric with a basis weight of 40 g / m 2 The material is a melt-blown nonwoven fabric (propylene), with an average fiber diameter of 25 μm, a thickness of 20 mm, manufactured by Inoac Corporation, and adhesive (moisture-curing urethane-based hot melt, manufactured by Taihei Chemack Co., Ltd., product number 708.1). 2 The average fiber diameter was 2.3 μm, product number: MER04, manufactured by Mitsui Chemicals, was laminated and bonded.

[0047] The specific method for measuring the sound absorption rate of a reverberation room is to place a sample of 500 mm square x 20 mm thick in a reverberation room (approximately 30 m 3 The sound-absorbing material of Comparative Example 2 (nonwoven fabric t20+nonwoven fabric) was placed on the floor surface of the room, with the substrate side facing upwards, while the sound-absorbing material of Example 1 (PUt20+nonwoven fabric) was placed with the polyurethane foam side facing upwards, and the sound absorption coefficient of each was measured.

[0048] The measurement results of the reverberation room sound absorption coefficient are shown in Figure 6. The four frequency ranges were the same as those for the measurement of the normal incidence sound absorption coefficient. The sound absorbing material of Example 1 (PUt20 + nonwoven fabric) had lower sound absorption properties than the sound absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) in the ultra-low frequency range, but had higher sound absorption properties than the sound absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) in all ranges from the low frequency range to the high frequency range. In addition, the sound-absorbing material of Example 1 (PUt20 + nonwoven fabric) showed a small decrease in sound absorption coefficient, with the sound absorption coefficient in the high frequency region decreasing by just under 10% compared to the sound absorption coefficient in the mid frequency region, whereas the sound-absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric) showed a large decrease in sound absorption coefficient, with the sound absorption coefficient in the high frequency region decreasing by just under 50% compared to the sound absorption coefficient in the mid frequency region.

[0049] The nonwoven fabric laminated to the substrate was the same in the sound-absorbing material of Example 1 (PUt20 + nonwoven fabric) and the sound-absorbing material of Comparative Example 2 (nonwoven fabric t20 + nonwoven fabric). However, the sound-absorbing material of Example 1 (PUt20 + nonwoven fabric) has a polyurethane foam substrate formed from a polyurethane foam raw material containing both sodium bicarbonate and malic acid (solid acid), and therefore has higher sound absorption properties than the sound-absorbing material of Comparative Example 2 (PUt20 + nonwoven fabric) which has a nonwoven fabric substrate, and the decrease in sound absorption rate from the mid-frequency range to the high-frequency range was slight.

[0050] The polyurethane foam of the example was cut to a thickness of 10 mm, and a nonwoven fabric was laminated on the polyurethane foam via an adhesive layer to produce a sound absorbing material (PUt10 + nonwoven fabric) of Example 2. The nonwoven fabric was the same as the nonwoven fabric used in the sound absorbing material (PUt20 + nonwoven fabric) of Example 1. The polyurethane foam of the example was cut to a thickness of 10 mm, and the sound absorbing material of the reference example (PUt10 alone) was produced using the polyurethane foam alone. The reverberation room sound absorption coefficient (JIS A 1409 compliant) was measured for the sound absorbing material of Example 2 (PUt10 + nonwoven fabric) and the sound absorbing material of the reference example (PUt10 alone).

[0051] The measurement results of the sound absorption coefficient in a reverberation room are shown in Figure 7. The sound absorbing material of Example 2 (PUt10 + nonwoven fabric) had higher sound absorption properties than the sound absorbing material of the reference example (nonwoven fabric t10 alone) in all frequency ranges from the infrasonic range to the high range. In addition, the sound absorption coefficient of the sound absorbing material of Example 2 (PUt10 + nonwoven fabric) was slightly higher in the high frequency range than in the mid frequency range, whereas the sound absorption coefficient of the sound absorbing material of the reference example (nonwoven fabric t10 alone) was almost the same in the mid frequency range and the high frequency range, and no improvement in the sound absorption coefficient was observed.

[0052] The sound-absorbing material of Example 2 (PUt10 + nonwoven fabric) is composed of a laminate of polyurethane foam and nonwoven fabric, and therefore has higher sound absorption properties than the sound-absorbing material of the reference example (PUt10 alone) composed of polyurethane foam alone, and there is no decrease in sound absorption rate from the mid-frequency range to the high-frequency range; in fact, the sound absorption rate is slightly higher.

[0053] Thus, the sound-absorbing material of the present invention exhibits little or no decrease in sound-absorbing properties even in the mid-frequency range and beyond, and has good sound-absorbing properties. [Explanation of symbols]

[0054] 10 Sound absorbing material 11 Polyurethane foam 21 Nonwoven fabrics

Claims

1. In sound-absorbing materials in which nonwoven fabric is laminated to polyurethane foam, The polyurethane foam has a density (JIS K7200) of 8 to 15 kg / m ３ and the air permeability (JIS K6400-7:2012) is 0.2 to 10 cc / cm ２ / s, The sound absorbing material has a reverberation chamber sound absorption coefficient (based on JIS A 1409) of 0.967 or more at 1 / 3 octave band center frequencies of 2000 Hz, 2500 Hz, and 3150 Hz, and the average value of the reverberation chamber sound absorption coefficient of the sound absorbing material is 0.947 or more at 1 / 3 octave band center frequencies of 4000 Hz, 5000 Hz, and 6300 Hz, However, this does not include a polyurethane foam produced by reacting and foaming a composition for producing polyurethane foam, which comprises a polyol, a polyisocyanate, a catalyst, a blowing agent, a foam stabilizer, and an auxiliary blowing agent, and which contains water as a blowing agent, the content of the water being 4 to 11 parts by mass relative to 100 parts by mass of the polyol, and which contains a liquid halogenated olefin as the auxiliary blowing agent, the content of the liquid halogenated olefin being 10 to 30 parts by mass relative to 100 parts by mass of the polyol. Sound absorbing material.

2. The sound-absorbing material described in claim 1, wherein the nonwoven fabric is made of olefin fibers.

3. The sound-absorbing material described in claim 1, wherein the nonwoven fabric is adhered to the polyurethane foam via an adhesive layer consisting of a layer of adhesive, and the adhesive is a moisture-curing urethane-based hot melt.

Images