JP2013246182A - Sound insulation material and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound insulation material which can be easily inserted in a gap of a sound transmission path in the vicinity of a vehicle fender, an instrument panel or a cowl, while ensuring excellent sound insulation performance.SOLUTION: A polyol component comprises 100 to 50 pts.mass of polyol having molecular weight of 3000 to 7000 and 0 to 50 pts.mass of polymer polyol. A polyurethane foam row material containing 0.3 to 5.0 pts.mass of crosslinking agent having molecular weight of 60 to 470 and a functional group number of 2 to 4 with respect to 100 pts.mass of polyol component, is molded to form polyurethane foam. A sound insulation material 10 is formed of the polyurethane foam. A coating layer 11 is formed on the surface of the polyurethane foam. A dynamic friction coefficient (JIS K7125) of the surface of the coating layer 11 is 0.9 or less. A surface hardness of the coating layer is 20 or less in Asker C hardness meter.

Description

  The present invention relates to a sound insulating material and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, in an automobile, a sound insulating material is disposed in a gap of a sound transmission path around a fender, an instrument panel, a cowl, and the like so as to suppress noise from being transmitted into the vehicle. Some sound insulation materials are made of polyurethane foam or felt.

  In the air gap in the sound transmission path, if there is a gap between the inner surface of the air gap and the sound insulating material, the sound insulating property is lowered. Therefore, it is preferable to form a sound insulating material having a predetermined amount larger than the gap with polyurethane foam having a compressive restoring property, and arrange the sound insulating material in the gap in a compressed state and closely contact the inner surface of the gap by a restoring force. The sound insulating material may be placed in the gap by fixing the sound insulating material to the inner surface of the gap with a double-sided adhesive tape, etc., and then covering the opening of the gap to close the sound insulating material to the inner surface of the gap. In such a case, there is a problem that it takes time to fix the sound insulating material or to close the opening of the air gap. Therefore, it is preferable that the sound insulating material made of polyurethane foam larger than the air gap is inserted into the air gap from the insertion opening of the air gap while being compressed and deformed, and is restored in the air gap so that the sound insulating material is densely arranged in the air gap.

  However, since the sound insulation material made of conventional polyurethane foam has a poor surface slip, when inserting a sound insulation material larger than the air gap into the air gap, not only is it difficult to insert smoothly due to frictional resistance with the inner surface of the air gap, There is a problem that even within the gap, it is difficult to restore smoothly due to friction with the inner surface of the gap, so that a gap is easily formed in the gap, and good sound insulation cannot be obtained. In order to improve the slip of the surface, it is conceivable to laminate a plastic sheet on the surface of the polyurethane foam, but in that case, the deformability of the polyurethane foam is impaired, which makes it difficult to insert into the gap. A gap is generated in the inside.

Japanese Utility Model Publication No. 63-177657 JP 2006-195055 A JP 2011-235794 A

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a sound insulating material that can be easily inserted into a gap in a sound transmission path and has good sound insulating properties, and a method for manufacturing the same.

  The invention of claim 1 is a sound insulating material comprising a polyurethane foam, wherein the polyurethane foam has a coating layer on a surface thereof, a coefficient of dynamic friction (JIS K7125) of the coating layer surface is 0.9 or less, and the surface hardness of the coating layer Is 20 or less on an Asker C hardness tester.

  The invention of claim 2 is the invention according to claim 1, wherein the air permeability of the polyurethane foam coating layer surface (JIS K6400-7A method) is 10 L / min or less, and the inner air permeability of the coating layer (JIS K6400-7A). Method) is 15 L / min or more, and the difference between the air permeability on the surface of the coating layer and the air permeability on the inner side is 10 L / min or more.

  Invention of Claim 3 manufactures the sound insulation material which molds the sound insulation material which consists of a polyurethane foam by inject | pouring the polyurethane foam raw material containing a polyol component, a crosslinking agent, a catalyst, a foaming agent, and an isocyanate into a foaming mold, and making it foam. In the method, the polyol component contains 100 to 50 parts by mass of a polyol having a molecular weight of 3000 to 7000, and the crosslinking agent has a molecular weight of 60 to 470, 2 to 4 functional groups, and 0.3 to 5 with respect to 100 parts by mass of the polyol component. 0.0 parts by weight, and after applying a branched wax-based mold release agent to the inner surface of the foam mold, the polyurethane foam raw material is injected and foamed to have a coating layer on the surface, The coefficient of dynamic friction (JIS K7125) on the surface of the coating layer is 0.9 or less, and the surface hardness is 20 or less with an Asker C hardness meter. And forming a sound insulating material made of polyurethane foam.

  The invention of claim 4 is characterized in that, in claim 3, the polyol component comprises 100 to 50 parts by mass of a polyol having a molecular weight of 3000 to 7000 and 0 to 50 parts by mass of a polymer polyol.

  According to the invention of claim 1, the polyurethane foam constituting the sound insulating material has a coating layer on the surface, and the dynamic friction coefficient (JIS K7125) of the coating layer surface is 0.9 or less. Since the surface slip is better than the dynamic friction coefficient of the surface (0.94 to 1.91) and the surface hardness of the polyurethane foam is 20 or less with an Asker C hardness meter, the sound insulating material has good compressibility and resilience. Therefore, when the sound insulating material of the present invention is inserted into a gap in a sound transmission path such as an automobile fender, an instrument panel, a cowl, etc. It can be smoothly restored and brought into close contact with the inner surface of the gap, and good sound insulation can be obtained.

  According to the invention of claim 2, the air permeability (JIS K6400-7A method) on the surface of the coating layer is 10 L / min or less, and the air permeability (JIS K6400-7A method) on the inner side of the coating layer is 15 L / min or more. Since the difference between the air permeability on the surface of the coating layer and the air permeability on the inner side is 10 L / min or more, good sound insulation is obtained by the coating layer on the surface having a low air permeability.

According to invention of Claim 3, the sound-insulation material of Claim 1 and 2 with favorable surface slip and sound insulation property can be manufactured easily.
According to the invention of claim 4, when inserted into the gap, a sound insulating material that maintains a firm holding property and improves a sound insulating property can be obtained.

It is a perspective view of the sound insulation material of one embodiment in the present invention. It is a fragmentary figure of the motor vehicle which shows a use position about the sound insulation material of one Embodiment in this invention.

  Hereinafter, embodiments of the present invention will be described. The sound insulating material 10 shown in FIG. 1 is inserted and arranged in the gap in the automobile fender shown in FIG. 2 with the A part facing upward and the B part facing downward, and is molded into a shape corresponding to the arranged gap. Made of molded polyurethane foam. The polyurethane foam has a coating layer 11 on the surface, the dynamic friction coefficient (JIS K7125) of the coating layer 11 surface is 0.9 or less, and the surface hardness of the polyurethane foam on which the coating layer 11 is formed is an Asker C hardness meter. 20 or less.

  When the coefficient of dynamic friction (JIS K7125) on the surface of the coating layer 11 is greater than 0.9, the slippage is poor and it is difficult to insert and arrange in the gap. A more preferable range of the dynamic friction coefficient is 0.8 to 0.1. Further, when the surface hardness of the polyurethane foam on which the coating layer 11 is formed (that is, the hardness of the coating layer surface) is larger than 20 by the Asker C hardness meter, the sound insulating material 10 is too hard and is inserted into the gap. Becomes difficult. A more preferable range of the surface hardness is 12 to 1 with an Asker C hardness meter.

  The polyurethane foam has an air permeability on the surface of the coating layer 11 (JIS K6400-7A method) of 10 L / min or less, and an inner side of the coating layer 11 (that is, an inner side away from the coating layer 11). (JIS K6400-7A method) is preferably 15 L / min or more, and the difference between the air permeability on the surface of the coating layer 11 and the air permeability on the inner side of the coating layer 11 is preferably 10 L / min or more. The difference between the air permeability on the surface of the coating layer 11, the air permeability on the inner side, the air permeability on the surface of the coating layer 11 and the air permeability on the inner side is within the above range. Better sound insulation is obtained. In particular, since the air permeability of the inner polyurethane foam is 15 L / min or more, the air inside the foam circulates to some extent at the time of compression insertion into the gap, so that the compression deformation at the time of insertion into the gap is not hindered. It will help ease. The more preferable range of the air permeability on the surface of the coating layer 11 is 8 to 2 L / min, the more preferable range of the air permeability on the inner side is 20 to 40 L / min, the air permeability of the surface of the coating layer 11 and the inner side. A more preferable range of the difference from the air permeability is 12 to 35 L / min.

  The sound insulating material 10 is manufactured by molding by injecting a polyurethane foam material into a foaming mold and foaming. Mold molding is a method often used as a method for molding polyurethane foam, and by setting the inner surface of a foam mold to a product shape, a polyurethane foam having a desired product shape can be obtained without post-processing. it can.

The polyurethane foam raw material contains a polyol component, a crosslinking agent, a catalyst, a foaming agent, and an isocyanate.
The polyol component is composed of 100 to 50 parts by mass of a polyol having a molecular weight of 3000 to 7000 and 0 to 50 parts by mass of a polymer polyol.
The polyol having a molecular weight of 3000 to 7000 may be either a polyether polyol or a polyester polyol. The polyol is not limited to one type and may be composed of a plurality of types. When the molecular weight of the polyol is less than 3000, the resulting sound insulating material made of polyurethane foam becomes hard, and when it exceeds 7000, the polyol has a high viscosity, and the raw materials such as polyol components are injected into the foam mold. Occasionally, the flowability of the raw material is deteriorated, the raw material is difficult to reach every corner of the mold, and there is a possibility that a void, a lack of meat, etc. are generated. The polyol having a molecular weight of 3000 to 7000 preferably has 2 to 4 functional groups.
The polymer polyol preferably has 2 to 4 functional groups and a molecular weight of 3000 to 5000. The amount of the polymer ol is 0 to 50 parts by mass in 100 parts by mass of the polyol component. When the amount of the polymer polyol exceeds 50 parts by mass, the polyurethane foam becomes too hard to be inserted into the void.

  The crosslinking agent has a molecular weight of 60 to 470 and a functional group number of 2 to 4. When the molecular weight is less than 60, there are almost no highly practical ones. Conversely, when the molecular weight exceeds 470, the reactivity becomes too low to contribute to film formation. As a crosslinking agent having a molecular weight of 60 to 470 and a functional group number of 2 to 4, ethylene glycol (functional group number 2, molecular weight 62.1), diethylene glycol (functional group number 2, molecular weight 106.1), glycerin (functional group number 3, molecular weight 92. 1), polyhydric alcohols such as butanetetraol (functional group number 4, molecular weight 122.1), polyoxypropylene glycol (functional group number 2-3, molecular weight 200-400), diethanolamine (functional group number 3, molecular weight 105.1) And polyamines. The crosslinking agent is not limited to one type and may be used in combination. The amount of the crosslinking agent is preferably 0.3 to 5 parts by mass with respect to 100 parts by mass of the polyol component. When the amount of the crosslinking agent is less than the above range, the effect of forming a film is small, and when the amount is large, the polyurethane foam becomes too hard to be inserted into the void.

  Examples of the catalyst include amine catalysts and metal catalysts used for polyurethane foams. Specific examples of the amine catalyst include N, N-dimethylcyclohexylamine, N, N-dimethylbenzylamine, N, N-dimethylaminoethanol, N, N ′, N′-trimethylaminoethylpiperazine, and triethylenediamine. Etc. are used. Examples of the metal catalyst include tin catalysts such as stass octoate and dibutyltin dilaurate, phenylmercury propionate and lead octenoate. The amount of the catalyst is about 0.1 to 8.0 parts by mass with respect to 100 parts by mass of the polyol component.

  Examples of the foaming agent include water, hydrocarbons, halogen compounds, and the like. One of these may be used, or two or more may be used. Examples of the hydrocarbon include cyclopentane, isopentane, and normal pentane. Examples of the halogen compound include methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, nonafluorobutyl ethyl ether, pentafluoroethyl methyl ether, heptafluoroisopropyl methyl ether and the like. Among these, water is particularly suitable as a foaming agent. The amount of water as the foaming agent is preferably about 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the polyol component.

  Isocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups, and those for polyurethane foam can be used. The isocyanate may be used alone or in combination of two or more. Examples of the isocyanate include aromatic, aliphatic, and alicyclic isocyanate compounds, and modified products thereof.

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), and tetramethylxylene diisosodium. Examples include dianate (TMXDI) and tolidine isocyanate (TODI). Examples of the aliphatic isocyanate compound include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). Examples of the alicyclic isocyanate compound include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H ₆ XDI), hydrogenated MDI (H ₁₂ MDI), and the like. Examples of the modified isocyanate compound include urethane-modified products, dimers, trimers, carbodiimide-modified products, allophanate-modified products, burette-modified products, urea-modified products, isocyanurate-modified products, oxazolidone-modified products, and isocyanate group-terminated prepolymers. Examples thereof include polymers.

  The amount of the isocyanate blended is preferably such that the isocyanate index is 80 to 120. When the isocyanate index is less than 80, the strength of the polyurethane foam is too low and the durability is poor, or the gas is difficult to escape and the molded state is poor. On the other hand, when the index exceeds 120, the polyurethane foam has high hardness, and it becomes difficult to insert the sound insulating material into the gap. The isocyanate index is a value indicating the equivalent ratio of the isocyanate group of the isocyanate to the total of the active hydrogen groups in the polyurethane foam raw material (for example, the active hydrogen group such as water used as a blowing agent). It is an indicator used in the field of polyureta foam.

  In addition, additives are appropriately blended. Examples of additives that are appropriately blended include foam stabilizers, flame retardants, colorants, fillers, and the like. Any foam stabilizer may be used as long as it is used for polyurethane foams, and examples thereof include silicone foam stabilizers, fluorine-containing compound foam stabilizers, and known surfactants.

  When molding the sound insulating material, first, a release agent is applied to the inner surface of the foaming mold. The foaming mold is a split mold that can be separated into an upper mold and the like, and the inner surface of the mold is the same shape as the outer shape of the sound insulating material. Further, the foaming mold has a heating means such as an electric heater or a heat medium circulation pipe embedded therein, and the temperature can be adjusted to a predetermined mold temperature by hot water or heating oil flowing through the electric heater or the heat medium circulation pipe. . The mold temperature is preferably 40 to 80 ° C. When the mold temperature is lower than 40 ° C., the curing property is deteriorated and the productivity is not good. On the contrary, when the mold temperature is higher than 80 ° C., the reactivity of the urethane raw material in contact with the mold becomes too high, There is a risk that the flowability of the urethane raw material will deteriorate, resulting in a lack of thickness and a rough appearance.

As the release agent, a branched wax-based release agent is used. As the branched wax-based release agent, a branched wax such as modified polyethylene wax, microcrystalline wax, hydrocarbon wax or the like is used as a main component, which is dissolved in an organic solvent, or water is added using an emulsifier. What is dispersed in is mentioned. The branched wax preferably has a melting point of 40 to 90 ° C.
When a release agent composed of a linear hydrocarbon wax or a release agent containing silicone is used in general, it is difficult to form a film on the foam surface, so-called skinless. On the other hand, when the specific cross-linking agent of the present invention is used in combination using a branched wax-based release agent, the coating layer 11 can be formed on the surface of the polyurethane foam. The release agent is applied by brush or spray. The application amount of the release agent is 30 to 300 g / m ² .

After the release agent is applied to the inner surface of the mold, the polyurethane foam raw material is mixed and injected into the foam mold, and the foam mold is closed. The injection amount is preferably such that the density of the polyurethane foam (JIS K7222: 2005) is 130 to 200 kg / m ³ (0.13 to 0.20 g / cm ³ ).
After foaming the polyurethane foam raw material, the foam molding die is opened and the sound insulating material 10 made of polyurethane foam is removed. The polyurethane foam which comprises the obtained sound-insulating material 10 has the said film layer 11 on the surface, and has the said physical property.

The following mold release agent A or B is sprayed (at a rate of about 100 g / m ² ) on the inner surface of a foam molding die (internal volume 4000 cm ³ ) having an inner surface dimension of 400 × 400 × 25 mm, the inner surface shape of which is a rectangular parallelepiped. ) The polyurethane foam raw material having the composition shown in Table 1 composed of the following raw materials was mixed and injected into a foaming mold, and foaming was performed while maintaining the mold temperature at 60 ° C. Thereafter, it was demolded to obtain sound insulating materials of Examples 1 to 7 and Comparative Examples 1 and 2 made of polyurethane foam. In Comparative Example 3, a polyurethane foam raw material having the composition shown in Table 1 was mixed and 360 g was injected into a foaming mold, and foaming was performed while maintaining the mold temperature at 60 ° C. The numerical value of the raw material in the composition of Table 1 is part by mass. Further, as Comparative Example 4, a slab foamed polyurethane foam (density 23 kg / m ³ , product number: Calm Flex F-4, manufactured by INOAC Corporation) was cut into the same dimensions as other examples and comparative examples, and sound insulating material Formed. In Comparative Example 4, since there was no coating on the surface, it was difficult to insert into the gap.

Polyol A: polyether polyol, molecular weight 3000, functional group number 3, hydroxyl value 56 mgKOH / g
Polyol B: polyether polyol, molecular weight 5000, functional group number 3, hydroxyl value 34 mgKOH / g
Polymer polyol: molecular weight 5000, functional group number 3, hydroxyl value 28 mgKOH / g
Crosslinking agent A: diethanolamine, 3 functional groups, molecular weight 105.1
Crosslinking agent B: ethylene glycol, functional group number 2, molecular weight 52.1
Crosslinking agent C: glycerin, 3 functional groups, molecular weight 92.1
-Crosslinking agent D: Polyether terol, functional group number 4, molecular weight 450, product name: EDP-450, manufactured by ADEKA-catalyst; amine catalyst, product name: 33LV, manufactured by Air Products Co., Ltd.-foaming agent: water-foam stabilizer ; Silicone foam stabilizer, product name: SZ1346E, manufactured by Toray Dow Corning Silicone Co., Ltd .; modified 4,4'-diphenylmethane diisocyanate, product name: Coronate 1050, manufactured by Nippon Polyurethane Industry Co., Ltd.-Release agent A; branched chain Wax release agent, product name: N-915, manufactured by Chukyo Yushi Co., Ltd., melting point 48 ° C.
-Release agent B; linear wax release agent, product name: URH-520, manufactured by Konishi Co., Ltd., melting point 92-102 ° C

  Example 1 is an example in which 50 parts by mass of polyol A and polymer polyol are used as the polyol component, Example 2 is an example in which polyol B is used alone, Example 3 and Example 4 are the amounts of polyol B and polymer polyol. When changed, and when Example 3 and Examples 5-7 differed in the type of crosslinking agent, Comparative Example 1 was compared when no crosslinking agent was used in the formulation of Example 3 and Examples 5-7. In Example 2, when the release agent B (linear wax release agent) was used instead of the release agent A (branched wax release agent) in Example 3, Comparative Example 3 had a crosslinking agent. In Comparative Example 1 that is not used, a release agent B (linear wax release agent) is used instead of the release agent A (branched wax release agent).

  With respect to Examples 1 to 7 and Comparative Examples 1 to 3, the moldability and the presence or absence of a surface coating layer were judged visually. Further, the density (JIS JIS K7222: 2005), surface hardness and sound insulation were measured. The formability was evaluated as “X” when there was a lack of thickness, down, shrink, or defective appearance, and “◯” when there was no defective appearance. The surface coating layer is “None” when no coating layer is present, the boundary between the coating layer and the inner side is unclear but “△” when the surface coating layer is present, and “Yes” when the coating layer is clearly present. " The surface hardness was measured with an Asker C hardness meter (Japan Rubber Association Standard SRIS 0101). Sound insulation was measured by transmission loss (acoustic transmission loss tube transmission matrix method: ASTM E2611-09 compliant, φ = 28.9 mm for thin tubes). For sound insulation, the measurement data is taken as transmission loss on the vertical axis, frequency (500 to 6300 Hz) on the horizontal axis, and the transmission loss is 10 decibels or less in consideration of the entire frequency range (500 to 6300 Hz). In the case of “x”, 10 to 20 dB, “Δ”, and in the case of 20 to 30 dB, “◯” was evaluated. Table 1 shows the measurement results.

  All of the sound insulating materials of Examples 1 to 7 had a moldability of “◯”, a surface coating layer, and a surface hardness of 20 or less with an Asker C hardness meter. Moreover, although the sound insulating material of Examples 1-7 was less than 20 decibels in the region of 500 to 900 Hz, it exceeded 30 decibels in the high frequency region exceeding 1000 Hz to 3500 HZ and 20 to 30 decibels. ○ ”.

  In contrast, Comparative Example 1 (without crosslinking agent, using release agent A (branched wax-based release agent)) has a surface coating layer of “Δ”, and Comparative Example 2 (crosslinking agent A and release agent B ( The surface coating layer was “none” in Comparative Example 3 (no crosslinking agent, no release agent B (linear wax release agent) used) and Comparative Example 3 (use of linear wax release agent)). As for the sound insulation, Comparative Example 1 and Comparative Example 2 were 10 to 20 decibels in the region of 4000 Hz or less, which is almost the entire frequency range, and therefore, the evaluation was Δ. In Comparative Example 3, the total frequency was In the region, since it was 7 to 18 decibels, the evaluation was x to Δ.

  Further, Example 3 and Comparative Example 2 (using a crosslinking agent A and a release agent B (linear wax-based release agent)) and Comparative Example 3 (without a crosslinking agent, release agent B (a linear wax-based release agent) The kinetic friction coefficient (JIS K7125) of the surface was measured with respect to (use of mold agent). The measurement results of the dynamic friction coefficient are as shown in Table 1. The dynamic friction coefficient of Example 3 was 0.76, whereas the dynamic friction coefficient of Comparative Example 2 was 1.91, and the dynamic friction coefficient of Comparative Example 3 was The surface friction coefficient of Example 3 is smaller than that of Comparative Example 2 and Comparative Example 3, and the slip is good.

  In addition, Example 3 and Comparative Example 2 (using a cross-linking agent A and a release agent B (linear wax-based release agent)) and Comparative Example 3 (no cross-linking agent, release agent B (linear wax-based) Of the foam molding die used in Example 1 or the like, using a polyurethane foam raw material of the mold release agent)), using a foam molding die having dimensions of 400 × 400 × 100 mm on the inner surface of the mold. According to the fact that the injection amount is four times that of Example 1, etc., the polyurethane foam was molded in the same manner as in the above case, and the third example was used for measuring air permeability. These were prepared as Comparative Example 2 and Comparative Example 3, and surface air permeability (JIS K6400-7A method) and internal side air permeability (JIS K6400-7A method) were measured. The surface breathability test piece is cut to a thickness of 10 mm from the surface of the polyurethane foam to a size of 51 × 51 × 10 mm, while the inner side breathability test piece is the center in the thickness direction of the molded polyurethane foam. The test piece for the measurement of the shape of the same dimension was prepared and used for measurement. Since Example 3 for measuring air permeability has a coating layer on the surface, the measurement of surface air permeability is the measurement of air permeability on the surface of the coating layer. On the other hand, since Comparative Example 2 and Comparative Example 3 for measuring air permeability do not have a coating layer on the surface, the measurement of surface air permeability is measurement of air permeability on the surface without the coating layer.

  The surface air permeability was 7 L / min in Example 3, while 15 L / min in Comparative Example 2 and 36 L / min in Comparative Example 3. Further, the inner side air permeability was 23 L / min in Example 3, whereas it was 22 L / min in Comparative Example 2 and 36 L / min in Comparative Example 3. Further, the difference between the surface air permeability and the internal side air permeability was 16 L / min in Example 3, whereas 7 L / min in Comparative Example 2 and 0 L / min in Comparative Example 3.

  Thus, according to the present invention, it is possible to obtain a sound insulating material that has a good surface slip, can be easily inserted into a gap, and has a good sound insulating property.

10 Sound insulation material 11 Coating layer

Claims (4)

In sound insulation material made of polyurethane foam,
The polyurethane foam has a coating layer on the surface,
The dynamic friction coefficient (JIS K7125) of the coating layer surface is 0.9 or less,
The sound insulating material, wherein the surface hardness of the coating layer is 20 or less by an Asker C hardness meter. The air permeability (JIS K6400-7A method) of the coating layer surface of the polyurethane foam is 10 L / min or less,
The inner side air permeability (JIS K6400-7A method) of the coating layer is 15 L / min or more,
The sound insulating material according to claim 1, wherein the difference between the air permeability of the surface of the coating layer and the air permeability of the inner side is 10 L / min or more. In a method for producing a sound insulation material, a polyurethane foam raw material containing a polyol component, a crosslinking agent, a catalyst, a foaming agent, and an isocyanate is injected into a foaming mold and foamed to mold a sound insulation material made of polyurethane foam.
The polyol component contains 100 to 50 parts by mass of a polyol having a molecular weight of 3000 to 7000,
The crosslinking agent comprises a molecular weight of 60 to 470, a functional group number of 2 to 4, and 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the polyol component.
After applying a branched wax-based release agent to the inner surface of the foaming mold, the polyurethane foam raw material is injected and foamed to have a coating layer on the surface, and the dynamic friction coefficient ( A method for producing a sound insulation material, comprising forming a sound insulation material comprising polyurethane foam having a JIS K7125) of 0.9 or less and a surface hardness of 20 or less by an Asker C hardness meter.   The said polyol component consists of 100-50 mass parts of polyols with a molecular weight of 3000-7000, and 0-50 mass parts of polymer polyols, The manufacturing method of the sound-insulating material of Claim 3 characterized by the above-mentioned.

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