Soundproofing material and method for producing the same

Abstract

To provide a soundproof material which is composed of polyurethane foam, is lightweight and has high sound insulating properties.SOLUTION: The air permeability (JISK6400 - 7:2012A method) of the coating layer is 10L / min or less, the air permeability (JISK6400 - 7:2012A method) on the inner side of the coating layer is 15L / min or more, and the relative density (JISK7222:2005) is less than 130kg / m3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a soundproofing material and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in automobiles, soundproofing materials are placed in gaps in the sound transmission path around the fenders, instrument panel, cowl, etc. to reduce the transmission of noise into the vehicle interior.

[0003] Conventional soundproofing materials are difficult to achieve both sound insulation and sound absorption properties with a single material, so some are made up of an integrated product that combines a high-density sound-insulating sheet to ensure sound insulation with polyurethane foam to ensure sound absorption (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 02-151899 Summary of the Invention [Problem to be solved by the invention]

[0005] However, soundproofing materials made of a sound-insulating sheet and polyurethane foam have the problem of being heavy. Also, when the surface on which the soundproofing material is installed is uneven, the presence of the sound-insulating sheet can impair the shape-following ability of the soundproofing material, resulting in gaps between the surface on which the soundproofing material is installed and the soundproofing material itself, which can result in poor sound insulation.

[0006] The present invention has been made in view of the above points, and has as its object to provide a lightweight soundproofing material with high sound insulation properties. [Means for solving the problem]

[0007] A first aspect of the present invention is a soundproofing material made of polyurethane foam, the polyurethane foam having a coating layer on its surface, the coating layer having an air permeability (JIS K6400-7:2012A method) of 10 L / min or less, the air permeability (JIS K6400-7:2012A method) of the inner side of the coating layer being 15 L / min or more, and the density (JIS K7222:2005) of the polyurethane foam being 130 kg / m 3 It is characterized in that it is less than

[0008] A second aspect of the invention is a method for producing a soundproofing material made of polyurethane foam, characterized in that a release agent having two melting peaks, one at 70 to 90°C and the other at 100 to 130°C, is applied to the inner surface of a foam molding die, polyurethane foam raw material is injected into the foam molding die and foamed, and polyurethane foam having a coating layer on its surface is molded, thereby producing a soundproofing material made of polyurethane foam having a coating layer on its surface.

[0009] A third aspect of the present invention is characterized in that, in the second aspect of the present invention, the release agent having two melting peaks is a mixed release agent containing a wax component having a weight-average molecular weight of 1,000 or more and a wax component having a weight-average molecular weight of 600 or less.

[0010] A fourth aspect of the invention is the polyurethane foam according to the second or third aspect of the invention, wherein the coating layer has an air permeability (JIS K6400-7:2012A method) of 10 L / min or less, an air permeability (JIS K6400-7:2012A method) of 15 L / min or more on the inner side than the coating layer, and a density (JIS K7222:2005) of 130 kg / m 3 It is characterized in that it is less than [Effects of the Invention]

[0011] According to the present invention, a lightweight soundproofing material with high sound insulation properties can be obtained. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a table showing the results of density, breathability, and sound insulation for each example and each comparative example. [Figure 2] 1 is a table showing the formulation of polyurethane foam raw materials used in each example and each comparative example. [Figure 3] 1 is a graph showing measurement results of transmission loss for some examples and some comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE INVENTION The soundproofing material of the present invention is made of polyurethane foam.

[0014] The polyurethane foam constituting the soundproofing material has a coating layer on its surface, and the breathability of the coating layer (JIS K6400-7:2012A method) is 10 L / min or less, preferably 8 L / min or less, and more preferably 5 L / min or less, and the breathability of the inner side of the surface coating layer (JIS K6400-7:2012A method) is 15 L / min or more, preferably 18 L / min or more, and more preferably 20 L / min or more.

[0015] The surface coating layer is the surface portion where the polyurethane foam cells are compressed, resulting in a layer that is denser than the inner (center) portion of the polyurethane foam. The thickness of the coating layer is usually about 0.001 to 3 mm. In the present invention, the inner side of the surface coating layer refers to the inner (central) part away from the surface coating layer, specifically the part 3 mm or more away from the surface of the polyurethane foam.

[0016] By setting the air permeability of the surface coating layer and the air permeability of the inner side of the polyurethane foam within the above ranges and making the air permeability of the surface coating layer lower than the air permeability of the inner side, good sound insulation properties can be obtained. The difference in air permeability between the surface coating layer and the inner side is preferably 10 L / min or more, more preferably 15 L / min or more, and even more preferably 20 L / min or more.

[0017] The density of the polyurethane foam that makes up the soundproofing material (JIS K7222:2005) is 130 kg / m 3 less than 100 kg / m 3 less than 80 to 40 kg / m 3 The density range of the polyurethane foam can be changed by varying the blending ratio of the polyurethane foam raw materials (mainly the amount of blowing agent) and the amount of polyurethane foam raw materials injected into the foam molding die. By setting the density of the polyurethane foam constituting the soundproofing material within the above range, the soundproofing material can be made lightweight.

[0018] The soundproofing material of the present invention is produced by molding, in which polyurethane foam raw material is injected into a foam mold and foamed. Molding is a widely used method for producing polyurethane foam, and by pre-forming the inner surface of the foam mold in the shape of the product, polyurethane foam in the desired shape can be obtained without post-processing.

[0019] The polyurethane foam raw materials include polyol, catalyst, crosslinking agent, blowing agent, and polyisocyanate. Polyols are compounds with two or more hydroxyl groups in one molecule, and are produced by addition polymerization of alcohols with two or more functional groups (polyhydric alcohols), or by using these as initiators with ethylene oxide or propylene oxide. The polyol may be any of polyether polyol, polyester polyol, and polymer polyol, and the polyol is not limited to one type, but may be a mixture of multiple types. The polyol preferably has 2 to 4 functional groups and a molecular weight of 3,000 to 7,000.

[0020] Examples of the catalyst include amine catalysts and metal catalysts used for polyurethane foams. Examples of the amine catalyst include N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylaminoethanol, N,N',N'-trimethylaminoethylpiperazine, and triethylenediamine. Examples of the metal catalyst include tin catalysts such as stannous octoate and dibutyltin dilaurate, phenylmercury propionate, and lead octenate. The amount of catalyst is preferably about 0.1 to 8.0 parts by weight per 100 parts by weight of the polyol.

[0021] Examples of crosslinking agents include polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, butanetetraol, and polyoxypropylene glycol, as well as diethanolamine and polyamine. The crosslinking agent is not limited to one type, and multiple types may be used in combination. The amount of crosslinking agent is preferably about 0.3 to 5 parts by weight per 100 parts by weight of polyol. If the amount of crosslinking agent is less than the above range, the effect of film formation tends to be reduced, and if it is more, the polyurethane foam tends to be too hard.

[0022] Examples of blowing agents include water, hydrocarbons, halogenated compounds, etc., and one or more of these may be used. Examples of hydrocarbons include cyclopentane, isopentane, and normal pentane. Examples of halogenated compounds include methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, nonafluorobutyl ethyl ether, pentafluoroethyl methyl ether, and heptafluoroisopropyl methyl ether. Among these, water is particularly suitable as a blowing agent. The amount of water used as a blowing agent is preferably about 1 to 10 parts by weight, more preferably about 1 to 7 parts by weight, per 100 parts by weight of polyol, which allows adjustment of the density of the polyurethane foam.

[0023] The polyisocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups, and those for polyurethane foams can be used. The polyisocyanate is not limited to one type, and two or more types may be used in combination. Examples of polyisocyanates include aromatic, aliphatic, and alicyclic isocyanate compounds, and modified products thereof.

[0024] Examples of aromatic isocyanate compounds include diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethyl xylene diisocyanate (TMXDI), and tolidine isocyanate (TODI). Examples of aliphatic isocyanate compounds include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). Examples of alicyclic isocyanate compounds include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H 12 Examples of modified isocyanate compounds include urethane-modified isocyanate compounds, dimers, trimers, carbodiimide-modified isocyanate compounds, allophanate-modified isocyanate compounds, biuret-modified isocyanate compounds, urea-modified isocyanurate-modified isocyanate compounds, oxazolidone-modified isocyanate compounds, and isocyanate-terminated prepolymers.

[0025] The amount of polyisocyanate blended is preferably an amount that results in an isocyanate index of 70 to 110. If the isocyanate index is less than 70, the polyurethane foam will have too low strength and poor durability, or it will be difficult for gas to escape, resulting in shrinkage and poor molding quality. On the other hand, if the isocyanate index exceeds 110, the polyurethane foam will have high hardness, making it difficult for the soundproofing material to deform to the shape of the mating surface. The isocyanate index is a value that indicates, as a percentage, the equivalent ratio of isocyanate groups in polyisocyanate to the total active hydrogen groups in the polyurethane foam raw materials (e.g., hydroxyl groups in polyols, active hydrogen groups such as water used as a blowing agent), and is an index used in the field of polyurethane foam.

[0026] In addition, additives may be added to the polyurethane foam raw materials as needed, such as a foam stabilizer, a foam opener, a flame retardant, and a colorant.

[0027] The foam stabilizer may be any foam stabilizer that is used in polyurethane foams, and examples thereof include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, and known surfactants.

[0028] The cell opener has the effect of destroying bubbles (gas bubbles) during foaming of polyurethane foam. The types of cell openers include hydrocarbon-based, ester-based, silicone-based, and polyol-based, and are not limited to one type, but two or more types may be used. Examples of hydrocarbon-based cell openers include oils such as polybutene. Examples of ester-based cell openers include dimer acid diesters. Examples of silicone-based cell openers include cyclopentasiloxane. Examples of polyol-based cell openers include polyether polyols with a high addition amount of ethylene oxide (EO ratio of 50% or more, preferably 60 to 100%).

[0029] When a cell opener is used, the amount is preferably about 0.01 to 15 parts by weight per 100 parts by weight of polyol. If the amount of cell opener is too large, it becomes difficult to achieve good foaming of the polyurethane foam.

[0030] The flame retardant may be a powder flame retardant such as a phosphorus-based flame retardant or ammonium polyphosphate, or a liquid flame retardant such as a phosphate ester-based flame retardant, and either one or both may be used in combination. The coloring agent to be used may be selected depending on the location where the soundproofing material is to be used.

[0031] When molding soundproofing materials, a mold release agent is first applied to the inner surface of the foam molding mold. The foam molding mold is composed of a split mold that can be separated into upper and lower molds, and the inner surface of the mold is shaped to match the outer shape of the soundproofing material. The foam molding mold also has a heating means such as an electric heater or a heat transfer medium circulating pipe embedded in it, and the mold temperature can be controlled to a predetermined value using hot water or heated oil flowing through the electric heater or heat transfer medium circulating pipe. The mold temperature is preferably around 50 to 70°C. If the mold temperature is lower than 50°C, the curing property will be poor and productivity will be reduced. Conversely, if the mold temperature is higher than 70°C, the reactivity of the polyurethane foam raw material will be too high, which will reduce the flowability of the polyurethane foam raw material and may result in underfill and a rough exterior surface.

[0032] The release agent used contains a solid component (wax component) that has two melting peaks: one at 70 to 90°C and the other at 100 to 130°C. The melting peaks are values ​​measured by a differential scanning calorimeter (DSC) on the solid component remaining after evaporating the liquid components of the release agent. When the release agent has two melting peaks, one at 70 to 90°C and the other at 100 to 130°C, a polyurethane foam with a good surface coating layer can be obtained.

[0033] The release agent having two melting peaks, one between 70 and 90°C and the other between 100 and 130°C, preferably contains a branched-chain wax-based release agent. Examples of branched-chain wax-based release agents include those that use a branched-chain wax, such as modified polyethylene wax, microcrystalline wax, or hydrocarbon wax, as the main component, dissolved in an organic solvent, or dispersed in water using an emulsifier. The branched-chain wax-based release agent facilitates the formation of a coating layer on the surface of the polyurethane foam.

[0034] The release agent having two melting peaks, one at 70 to 90°C and the other at 100 to 130°C, is preferably a mixed release agent containing a wax component having a weight-average molecular weight of 1000 or more and a wax component having a weight-average molecular weight of 600 or less.

[0035] The release agent can be applied to the inner surface of the foam molding mold by brush or spray. The amount of release agent applied is 10 to 100 g / m. 2 is preferred.

[0036] After applying a mold release agent to the inner surface of the foam molding mold, the polyurethane foam raw material is mixed and injected into the foam molding mold, and the foam molding mold is closed. The amount of polyurethane foam raw material injected into the foam molding mold is set so that the density of the resulting polyurethane foam (JIS K7222:2005) is 130 kg / m 3 (0.13g / cm 3 ) is considered to be an amount less than that.

[0037] After foaming the polyurethane foam raw material, the foam mold is opened and the soundproofing material made of polyurethane foam is demolded. The polyurethane foam constituting the obtained soundproofing material has a coating layer on its surface and has the physical properties described above. [Example]

[0038] The inner surface of the mold is a rectangular parallelepiped foam molding mold with inner dimensions of 500 x 500 x 20 mm (mold volume: 5000 cm). 3 ) and a foam molding mold with inner dimensions of 500 × 250 × 40 mm (mold volume 5000 cm3 The release agent selected from the following release agents A, B, and C according to each example and comparative example shown in FIG. 1 was sprayed onto the inner surface of the mold (approximately 25 g / m 2 The polyurethane foam raw material having the composition shown in Figure 2, which was made up of the following raw materials, was mixed and poured into a foam molding die in an amount that would give the density set for each Example and Comparative Example, and foaming was carried out while maintaining the die temperature at 60°C. The soundproofing materials made of polyurethane foam for each Example and Comparative Example were then demolded to obtain them.

[0039] Release agent A: Branched wax-based release agent, first melting peak 81.0°C, second melting peak 110.2°C, product name: FRX-C8, manufactured by Neos Co., Ltd. Release agent B: Branched wax-based release agent, melting point 106.9°C, product name: M975, manufactured by Chukyo Yushi Co., Ltd. Release agent C: Straight chain wax-based release agent, first melting peak 93.2°C, second melting peak 108.3°C, product name: T-626, manufactured by Chukyo Yushi Co., Ltd. Polyol A: Polyether polyol, molecular weight 7000, functionality 3, EO content 14%, product name: KC-737, manufactured by Sanyo Chemical Industries, Ltd. Polyol B: Polyether polyol, molecular weight 5000, functionality 3, EO content 14%, product name: FA-703, manufactured by Sanyo Chemical Industries, Ltd. Polyol C: Polymer polyol, molecular weight 5000, functional group 3, product name: FA-728R, manufactured by Sanyo Chemical Industries, Ltd. Catalyst A: Amine catalyst, product name: DABCO BL-11, manufactured by Evonik Catalyst B: Amine catalyst, product name: DABCO 33LSI, manufactured by Evonik Catalyst C: Amine catalyst, product name: TOYOCAT D-60, manufactured by Tosoh Corporation Crosslinking agent: Diethanolamine Foam stabilizer: Silicone foam stabilizer, product name: B8738LF2, manufactured by Evonik Foam opener: Polyether polyol, molecular weight 4800, functionality 3, PO / EO = 30 / 70 (EO ratio 70%), product name: CP1421, manufactured by Dow Chemical Company Foaming agent: water Polyisocyanate: Polymeric MDI, NCO%: 31.5%, Product name: 600B, manufactured by BASF INOAC Polyurethanes Co., Ltd.

[0040] The polyurethane foams (soundproofing materials) of each example and each comparative example were measured for density (JIS K7222:2005), air permeability of the surface coating layer (JIS K6400-7:2012A method), and air permeability of the interior side (JIS K6400-7:2012A method).

[0041] The breathability of the coating layer was measured by cutting a 10 mm portion from the surface of a polyurethane foam molded with dimensions of 500 × 250 × 40 mm to obtain a 51 × 51 × 10 mm test piece for the coating layer. On the other hand, the breathability of the inner side was measured by cutting a central portion in the thickness direction of the molded polyurethane foam (10 to 20 mm away from the surface) to prepare an inner test piece of the same dimensions (51 × 51 × 10 mm) for use in the measurements.

[0042] When the breathability of the coating layer was 5 L / min or less, the breathability of the coating layer was evaluated as "◎", when it was between 5 L / min and 10 L / min or less, the breathability of the coating layer was evaluated as "〇", and when it was more than 10 L / min, the breathability of the coating layer was evaluated as "▲". When the difference in air permeability between the coating layer and the inner side was 20 L / min or more, the air permeability difference evaluation was "◎", when the difference in air permeability was 15 L / min or more but less than 20 L / min, the air permeability difference evaluation was "〇", and when the difference in air permeability was less than 15 L / min, the air permeability difference evaluation was "▲". An overall judgment of breathability was made based on the breathability evaluation and breathability difference evaluation of the coating layer according to the following criteria: When both the breathability evaluation and breathability difference evaluation of the coating layer were "◎", the overall breathability judgment was "◎", when either the breathability evaluation or the breathability difference evaluation of the coating layer was "◎" and the other was "〇", or when both were "〇", the overall breathability judgment was "〇", and when either or both of the breathability evaluation and the breathability difference evaluation of the coating layer were "▲".

[0043] Also, density 50kg / m 3 Example 1, Comparative Example 1, Comparative Example 5, density 150 kg / m 3The soundproofing material of Comparative Example 9 was evaluated for sound insulation. Sound insulation was evaluated by measuring sound transmission loss (JIS A1441-1:2007 / ISO 15186-1:2000) in a 1 / 3 octave band and calculating the average sound transmission loss (average sound transmission loss) over the frequency range of 400 Hz to 4 kHz. This average sound transmission loss is preferably 12 dB or more, more preferably 14 dB or more, and even more preferably 16 dB or more. If the average value of the transmission loss (average transmission loss) between 400Hz and 4kHz was 16dB or more, it was marked as "◎", if it was 12dB or more and less than 16dB, it was marked as "〇", if it was 8dB or more and less than 12dB, it was marked as "△", and if it was less than 8dB, it was marked as "×". It is preferable to judge the sound insulation by comparing at the same density. The sound source reverberation chamber used for the measurement of transmission loss was 36m 3 , the anechoic chamber is 20m 3 , measurement area is 400 × 400 mm (0.16 m 2 ) The soundproofing material, made of polyurethane foam and measuring 500mm square and 20mm thick (with a surface coating layer), was fixed in a 50mm wide frame around the periphery, and the gaps were further sealed with clay. Sound was incident from the reverberation chamber (the sound source side), and measurements were taken from the anechoic receiving chamber (the non-sound source side) at 25 locations (80mm pitch) 215mm away from the surface of the soundproofing material over the range of 250Hz to 10kHz, and the average value from 400Hz to 4kHz was calculated. The measurement results are shown in Figure 3.

[0044] In Examples 1 and 2, release agent A was used, the isocyanate index was set to 80, and the density of the polyurethane foam was set to 50 kg / m 3 (Example 1) and 70 kg / m 3 This is an example that is different from (Example 2).

[0045] Example 1 (density 50 kg / m 3) had an internal air permeability of 56.6 L / min, an internal air permeability of 3.0 L / min for the surface coating layer, an air permeability difference of 53.6 L / min for the surface coating layer and the internal side, an evaluation of "◎", an overall air permeability evaluation of "◎", an average transmission loss of 14.3 dB from 400 Hz to 4 kHz, and a sound insulation evaluation of "◎". Example 1 had higher sound insulation than Comparative Example 1, which had the same density and had an average transmission loss of 10.9 dB from 400 Hz to 4 kHz, and was evaluated as "good" for sound insulation.

[0046] Example 2 (density 70 kg / m 3 ) had an internal breathability of 22.0 L / min, an internal breathability of 3.5 L / min for the surface coating layer, and a rating of "◎." The difference in breathability between the surface coating layer and the internal side was 18.5 L / min, and a rating of "〇." Overall breathability was judged to be "〇."

[0047] In Examples 3 and 4, release agent A was used, the isocyanate index was set to 100, and the density of the polyurethane foam was set to 50 kg / m 3 (Example 3) and 70 kg / m 3 This is an example that is different from (Example 4).

[0048] Example 3 (density 50 kg / m 3 ) had an internal breathability of 55.0 L / min, an internal breathability of 3.7 L / min for the surface coating layer, and a rating of "◎." The difference in breathability between the surface coating layer and the internal side was 51.2 L / min, and a rating of "◎." Overall breathability was judged to be "◎."

[0049] Example 4 (density 70 kg / m 3 ) had an internal breathability of 24.1 L / min, an external coating layer breathability of 3.9 L / min, and a rating of "◎." The difference in breathability between the external coating layer and the internal side was 20.3 L / min, and a rating of "◎." Overall breathability was judged to be "◎."

[0050] In Comparative Examples 1 and 2, release agent B was used, the isocyanate index was set to 80, and the density of the polyurethane foam was set to 50 kg / m 3 (Comparative Example 1) and 70 kg / m 3 This is an example that is different from (Comparative Example 2).

[0051] Comparative example 1 (density 50kg / m 3 ) had an internal air permeability of 58.6 L / min, an internal air permeability of 26.9 L / min for the surface coating layer, and a rating of "▲." The difference in air permeability between the surface coating layer and the internal side was 31.7 L / min, and a rating of "◎." Overall air permeability was judged to be "▲." The average transmission loss at 400 Hz-4 kHz was 10.9 dB, and the sound insulation was lower than that of Example 1 with the same density, and the sound insulation was judged to be "△."

[0052] Comparative example 2 (density 70kg / m 3 ) had an internal breathability of 22.1 L / min, an internal breathability of 9.2 L / min for the surface coating layer, and a rating of "Good." The difference in breathability between the surface coating layer and the internal side was 12.9 L / min, and a rating of "▲." Overall breathability was judged to be "▲."

[0053] In Comparative Examples 3 and 4, release agent B was used, the isocyanate index was set to 100, and the density of the polyurethane foam was set to 50 kg / m 3 (Comparative Example 3) and 70 kg / m 3 This is an example that is different from (Comparative Example 4).

[0054] Comparative example 3 (density 50kg / m 3 ) had an internal breathability of 68.6 L / min, an internal breathability of 14.0 L / min for the surface coating layer, and a rating of "▲." The difference in breathability between the surface coating layer and the internal side was 54.6 L / min, and a rating of "◎." Overall breathability was judged to be "▲."

[0055] Comparative example 4 (density 70kg / m 3 ) had an internal breathability of 35.1 L / min, an internal breathability of 14.7 L / min for the surface coating layer, and a rating of "▲." The difference in breathability between the surface coating layer and the internal side was 20.5 L / min, and a rating of "〇." The overall breathability rating was "▲."

[0056] In Comparative Examples 5 and 6, release agent C was used, the isocyanate index was set to 80, and the density of the polyurethane foam was set to 50 kg / m 3 (Comparative Example 5) and 70 kg / m 3 This is an example that is different from (Comparative Example 6).

[0057] Comparative example 5 (density 50kg / m 3 ) had an internal air permeability of 47.3 L / min, an internal air permeability of 14.7 L / min for the surface coating layer, and was rated as "▲." The difference in air permeability between the surface coating layer and the internal side was 32.6 L / min, and was rated as "◎." Overall air permeability was judged as "▲." The average transmission loss at 400 Hz-4 kHz was 7.5 dB, and the sound insulation was lower than that of Example 1 and Comparative Example 1 of the same density, and the sound insulation was judged as "×."

[0058] Comparative example 6 (density 70kg / m 3 ) had an internal breathability of 21.3 L / min, an internal breathability of 7.3 L / min for the surface coating layer, and a rating of "Good." The difference in breathability between the surface coating layer and the internal side was 14.0 L / min, and a rating of "▲." Overall breathability was judged to be "▲."

[0059] In Comparative Examples 7 and 8, release agent C was used, the isocyanate index was set to 100, and the density of the polyurethane foam was set to 50 kg / m 3 (Comparative Example 7) and 70 kg / m 3 This is an example that is different from (Comparative Example 8).

[0060] Comparative example 7 (density 50kg / m 3 ) had an internal breathability of 54.4 L / min, an internal breathability of 18.9 L / min for the surface coating layer, and a rating of "▲." The difference in breathability between the surface coating layer and the internal side was 35.5 L / min, and a rating of "◎." Overall breathability was judged to be "▲."

[0061] Comparative example 8 (density 70kg / m 3 ) had an internal breathability of 26.1 L / min, an internal breathability of 11.5 L / min for the surface coating layer, and a rating of "▲". The difference in breathability between the surface coating layer and the internal side was 14.6 L / min, and a rating of "▲". Overall breathability was rated as "▲".

[0062] In Comparative Example 9, release agent B was used, the isocyanate index was set to 100, and the density of the polyurethane foam was set to 150 kg / m 3 This is an example. In Comparative Example 9, the air permeability on the inner side was 24.8 L / min, the air permeability of the surface coating layer was 7.8 L / min, and the evaluation was "good." The difference in air permeability between the surface coating layer and the inner side was 17.0 L / min, and the evaluation was "good." The overall air permeability was judged to be "good." The average transmission loss from 400 Hz to 4 kHz was 15.8 dB. Since release agent B, which is different from the release agent of the present invention, was used, the sound insulation was lower than that of Example 5 of the same density, and the sound insulation was judged to be "good." Comparative Example 9 has a density of 150 kg / m 3 Because it is expensive, it has good sound insulation but is heavy.

[0063] In Comparative Example 10, release agent C was used, the isocyanate index was set to 100, and the density of the polyurethane foam was set to 150 kg / m 3 This is an example. In Comparative Example 10, the air permeability on the inner side was 31.8 L / min, the air permeability of the surface coating layer was 30.2 L / min, and the rating was "▲". The difference in air permeability between the surface coating layer and the inner side was 1.6 L / min, and the rating was "▲". The overall air permeability rating was "▲".

[0064] As described above, according to the present invention, a lightweight soundproofing material with high sound insulation properties can be obtained. Note that the present invention is not limited to the examples, and modifications can be made without departing from the spirit of the invention.

Claims

1. In soundproofing materials made of polyurethane foam, The polyurethane foam has a coating layer on its surface, and the coating layer has an air permeability (JIS K6400-7:2012A method) of 10 L / min or less, and an air permeability (JIS K6400-7:2012A method) on the inner side of the coating layer of 15 L / min or more, and a density (JIS K7222:2005) of 130 kg / m ３ A soundproofing material characterized in that it is less than

2. A method for producing a soundproofing material made of polyurethane foam, comprising: A method for producing a soundproofing material, comprising: applying a mold release agent having two melting peaks, one at 70 to 90°C and the other at 100 to 130°C, to the inner surface of a foam molding die; injecting polyurethane foam raw material into said foam molding die and foaming it; and molding a polyurethane foam having a coating layer on its surface, thereby producing a soundproofing material composed of polyurethane foam having a coating layer on its surface.

3. 3. The method for producing a soundproofing material according to claim 2, wherein the release agent having two melting peaks is a mixed release agent containing a wax component having a weight-average molecular weight of 1,000 or more and a wax component having a weight-average molecular weight of 600 or less.

4. The polyurethane foam having a coating layer on its surface has an air permeability (JIS K6400-7:2012A method) of the coating layer of 10 L / min or less, an air permeability (JIS K6400-7:2012A method) of 15 L / min or more on the inner side than the coating layer, and a density (JIS K7222:2005) of 130 kg / m ３ 4. The method for producing a soundproofing material according to claim 2, wherein the thickness is less than 1 / 2 mm.

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