Soundproofing material and method for manufacturing the same

Abstract

This sound-proofing material comprises a polyurethane foam. The sound-proofing material contains, in at least a portion thereof, a double-walled structure region composed of a first skin layer, a core layer and a second skin layer, in which the density ratio of a first skin layer region A is 1.05 or more and the density ratio of a second skin layer region A is 1.05 or more. Furthermore, the sound-proofing material has an overall (OA) density of 130 kg / m3 or less. The sound-proofing material is produced by preparing a raw material mixture containing a relatively large amount of a low-molecular-weight polyol, then applying a mold release agent comprising a wax component having two melting peaks and a branched structure onto an inner surface of a mold, and then foaming and curing the raw material mixture in the mold.

Description

[Technical Field]

[0001] The present invention relates to a soundproofing material and a method for manufacturing the same, and more particularly to a low-density soundproofing material made of polyurethane foam that has excellent sound absorption and sound insulation properties, and a method for manufacturing the same. [Background technology]

[0002] Polyurethane refers to a polymer compound having a urethane bond (-NH-C(O)O-). Generally, polyurethane is obtained by reacting the hydroxyl group (-OH) of a polyol with the isocyanate group (-NCO) of a polyisocyanate. Polyurethane is known to exhibit diverse properties by optimizing the type of polyol and / or polyisocyanate used. Therefore, polyurethane is used in various applications such as automotive parts, synthetic leather, paints, and adhesives. Furthermore, polyurethane foam, obtained by foaming polyurethane, is used in applications such as thermal insulation and cushioning materials.

[0003] Polyurethane foam is (a) Flexible polyurethane foam in which air bubbles are interconnected, (b) Rigid polyurethane foam in which air bubbles are independent, (c) Semi-rigid polyurethane foam with properties intermediate between rigid and flexible. They can be broadly categorized into these two groups.

[0004] Of these, flexible polyurethane foam is known to exhibit sound absorption properties. When sound enters flexible polyurethane foam, the sound enters the interconnected bubbles and is reflected in various directions within the bubbles. At that time, viscous friction of air occurs on the inner surface of the interconnected bubbles. As a result, some of the sound energy is converted into thermal energy due to friction, and the sound is attenuated. For this reason, flexible polyurethane foam is used as a soundproofing material, for example, by placing it in gaps that serve as sound propagation paths in automobiles (e.g., gaps around fenders, instrument panels, and cowls).

[0005] Regarding such sound insulation materials, various proposals have been made in the past. For example, in Patent Documents 1 and 2, (a) Polyether polyol with a functionality of 3 and a molecular weight of 5000: 90 parts by mass, (b) Polymer polyol with a functionality of 3 and a molecular weight of 5000: 10 parts by mass, (c) Diethanolamine (crosslinking agent): 1 part by mass, (d) Amine catalyst: 0.95 part by mass, (e) Water (foaming agent): 1.3 parts by mass, (f) Silicone foam stabilizer: 0.17 part by mass, and (g) Modified 4,4'-diphenylmethane diisocyanate: 41.7 parts by mass (corresponding to an isocyanate index = 100) A sound insulation material obtained by reacting a raw material containing the above is disclosed.

[0006] In the same document, by such a method, (A) Having a coating layer on the surface, (B) The dynamic friction coefficient of the coating layer surface is 0.762, (C) The surface hardness of the coating layer is 2 on an Asker C hardness meter, (D) The air permeability of the surface is 7 L / min, (E) The air permeability inside is 23 L / min, (F) The density is 135 kg / m , ,

[0008] , , is described <00001​​​​​​​​​​​​​​​​​​​ The document states that by this method, (A) Young's modulus is 1.6 × 10⁻⁶ 5 N / m 2 And, (B) Density is 104 kg / m³ 3 And, (C) Air permeability resistance of 3000 Ns / m 3 That is It is stated that soundproofing material can be obtained from it.

[0009] Soundproofing materials are required to have not only high sound absorption properties but also high sound insulation properties (high transmission loss). To increase transmission loss, it is necessary to increase the density and thickness of the soundproofing material. In soundproofing materials made of polyurethane foam, a high-density skin layer is provided on the surface to give it sound insulation properties. However, conventional soundproofing materials made of polyurethane foam do not have sufficient sound insulation properties. On the other hand, increasing the density of the skin layer or increasing its thickness to improve sound insulation would increase the weight of the soundproofing material, which goes against the need for lightweight materials.

[0010] Furthermore, when molding polyurethane foam, applying a release agent to the mold surface allows for the formation of a stronger skin layer on the molded product surface. However, if the type of release agent is inappropriate, open pores may form on the surface of the skin layer when the overall density of the polyurethane foam is reduced. When open pores form on the surface of the skin layer, the sound insulation performance of the soundproofing material decreases. On the other hand, using a common release agent that does not easily form open pores may result in cellular roughness on the surface, which can reduce the sound insulation performance of the soundproofing material.

[0011] To solve this problem, (A) A method of integrally molding the film and polyurethane foam by pouring polyurethane raw material onto the surface of the film. (B) A method in which paint is sprayed onto the cavity surface of the mold to form a surface layer, and then polyurethane raw material is poured into the mold to integrally mold the surface layer and polyurethane foam (the so-called "mold coating method"). It is also possible to use methods such as the following.

[0012] However, soundproofing materials, including films, have poor shape conformability. This can lead to wrinkles forming on the surface of the soundproofing material, resulting in poor sealing performance. Furthermore, the mold coating method is prone to paint staining around the mold. In addition, all of these methods increase the cost of soundproofing materials. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Japanese Patent Publication No. 2013-246182 (Japanese Patent No. 6137783) [Patent Document 2] Japanese Patent Publication No. 2017-142532 (Japanese Patent Publication No. 6352491) [Patent Document 3] Japanese Patent Publication No. 2006-195055 (Japanese Patent Publication No. 4757498) [Overview of the Initiative] [Problems that the invention aims to solve]

[0014] The problem that this invention aims to solve is to provide a soundproofing material made of polyurethane foam that has excellent sound absorption and sound insulation properties and is low in density. Another problem that the present invention aims to solve is to provide a method for manufacturing soundproofing materials that can be produced at low cost. [Means for solving the problem]

[0015] To solve the above problems, the soundproofing material according to the present invention The polyurethane foam comprises a double-wall structure region consisting of a first skin layer / core layer / second skin layer, The density ratio of the first skin layer region A is 1.05 or higher. The density ratio of the second skin layer region A is 1.05 or higher. Overall (OA) density is 130 kg / m³ 3 It is less than.

[0016] The method for manufacturing soundproofing material according to the present invention is: A first step involves preparing a raw material mixture for the manufacture of polyurethane foam, which includes a polyol component, a polyisocyanate component, a catalyst, a blowing agent, and low molecular weight polyols. The second step involves applying a release agent to the inner surface of the mold, A third step involves injecting the raw material mixture into a mold coated with the release agent, foaming and hardening the raw material mixture within the mold, and obtaining the soundproofing material according to the present invention. Equipped with, The aforementioned release agent contains a wax component having two melting peaks and a branched chain structure. The aforementioned raw material mixture may further contain low molecular weight amine compounds. [Effects of the Invention]

[0017] When a mold release agent is applied to a mold, a raw material mixture for polyurethane foam manufacturing is injected into the mold, and the raw material mixture is foamed and cured inside the mold, the mold release agent suppresses the generation of air bubbles on the mold surface. As a result, a soundproofing material is obtained that includes a double-wall structure region consisting of a first skin layer / core layer / second skin layer. In this case, if low molecular weight polyols, or low molecular weight polyols and low molecular weight amine compounds are added to the raw material mixture, and a mold release agent containing a wax component with two melting peaks and a branched chain structure is used, a low-density soundproofing material with excellent sound absorption and sound insulation properties can be manufactured at low cost.

[0018] The soundproofing material according to the present invention exhibits high sound insulation performance despite being lighter than conventional polyurethane soundproofing materials. This is because, (A) By adding low molecular weight polyols, or low molecular weight polyols and low molecular weight amine compounds, to the raw material mixture, the density ratio of the first skin layer region A and the density ratio of the second skin layer region A increased, further improving the sound insulation effect of the double wall, and (B) By using a release agent containing a wax component with two melting peaks and a branched chain structure, the formation of open pores and cell roughness on the surface of the skin layer is suppressed, and the sound insulation effect of the double wall is further improved. It is thought that... [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows the measurement results of the sound transmission loss of the soundproofing materials obtained in Examples 1-3, Comparative Example 1, and Comparative Example 5. [Modes for carrying out the invention]

[0020] One embodiment of the present invention will be described in detail below. [1. Soundproofing materials] The soundproofing material according to the present invention has the following configuration. (1) The soundproofing material is made of polyurethane foam. (2) The soundproofing material is provided with at least a portion of a double-wall structure region consisting of a first skin layer / core layer / second skin layer, The density ratio of the first skin layer region A is 1.05 or higher. The density ratio of the second skin layer region A is 1.05 or higher. (3) The soundproofing material has an overall (OA) density of 130 kg / m³ 3 It is less than.

[0021] [1.1. Materials] The soundproofing material according to the present invention is made of polyurethane foam. The polyurethane foam constituting the soundproofing material preferably has a three-dimensional crosslinked structure. Examples of polyurethane foams having a three-dimensional crosslinked structure include: (a) obtained by reacting a raw material mixture containing a polyol having 3 or more functional groups and / or a polyisocyanate having 3 or more functional groups, (b) obtained by reacting a raw material mixture in which both the polyol and polyisocyanate have 2 functional groups and the polyisocyanate is in excess, thereby generating a burette and / or allophanate in the polymer chain. These are some examples. The polyurethane foam that constitutes the soundproofing material is not particularly limited, as long as it satisfies the conditions described later.

[0022] [1.2. Double wall structure area] A "double-wall structure region" is, (a) Two surfaces face each other along the direction of sound propagation, (b) One surface side has a first skin layer, (c) The other surface side has a second skin layer, (d) There is a core layer between the first skin layer and the second skin layer. It refers to a domain or area.

[0023] The "skin layer" refers to a region with a higher density than the interior (core layer) (i.e., a region with a lower foaming ratio than the interior). Normally, when polyurethane raw materials are foamed, a skin layer is formed on the outer surface. When polyurethane foam is mold-molded, applying a release agent to the mold surface suppresses the generation of air bubbles on the mold surface. As a result, a stronger skin layer can be formed. The thickness of the skin layer can be controlled by the manufacturing conditions.

[0024] The soundproofing material may include a double-wall structure in part, or it may consist entirely of a double-wall structure. When either the first skin layer or the second skin layer is arranged on the sound source side, when sound is incident on the skin layer on the sound source side, a part of the sound is reflected (sound insulation) by the skin layer on the sound source side. The sound that passes through the skin layer on the sound source side is attenuated (sound absorption) when passing through the core layer. Furthermore, a part of the sound that passes through the core layer is reflected (sound insulation) by the skin layer arranged on the side opposite to the sound source, and the remaining sound passes through the skin layer. Therefore, the soundproof material having a double-wall structure region exhibits high soundproof performance (sound absorption performance, sound insulation performance).

[0025] [1.3. Density ratio] The "density ratio of the first skin layer region A" refers to the ratio of the density (ρ c ) of the first skin layer region A to the density (ρ s1 ) of the core layer region A (= ρ s1 / ρ c ). The "density ratio of the second skin layer region A" refers to the ratio of the density (ρ c ) of the second skin layer region A to the density (ρ s2 ) of the core layer region A (= ρ s2 / ρ c ). The "density" refers to the value measured in accordance with JIS K7222:2005.

[0026] The "core layer region A" is a region defined when measuring the density, and refers to a region that does not include the high-density region on the surface layer. Specifically, the "core layer region A" refers to the region within ±t A / 2 from the center of the double-wall structure region. The "first skin layer region A" is a region defined when measuring the density, and refers to a region that includes the high-density region on the surface layer on the first skin layer side. Specifically, the "first skin layer region A" refers to the region from the surface on the first skin layer side to a depth of t A . The "second skin layer region A" is a region defined when measuring the density, and refers to a region that includes the high-density region on the surface layer on the second skin layer side. Specifically, the "second skin layer region Area A” refers to the region from the surface on the second skin layer side to a depth of t A . tA = 5.0 mm or t0 × 0.125 (where t0 is the thickness of the double-wall structure region)

[0027] The density ratio of the first skin layer region A affects the sound insulation performance of the soundproofing material. Generally, the higher the density ratio of the first skin layer region A, the higher the sound insulation performance. To obtain high sound insulation performance, the density ratio of the first skin layer region A needs to be 1.05 or higher. Preferably, the density ratio is 1.08 or higher, 1.10 or higher, 1.15 or higher, or 1.20 or higher.

[0028] Similarly, the density ratio of the second skin layer region A affects the sound insulation performance of the soundproofing material. Generally, the higher the density ratio of the second skin layer region A, the higher the sound insulation performance. To obtain high sound insulation performance, the density ratio of the second skin layer region A needs to be 1.05 or higher. Preferably, the density ratio is 1.08 or higher, 1.10 or higher, 1.15 or higher, or 1.20 or higher.

[0029] The conditions for the density ratio of the first skin layer region A and the second skin layer region A are as follows: (A) When the density of each region is measured using a sample with a thickness of 5.0 mm, or (B) When the density of each region is measured using a sample with a thickness of t0 × 0.125 It is sufficient if at least one of the following conditions is met.

[0030] When polyurethane foam is molded using a split upper and lower mold, the skin layer formed on the lower mold side usually has a better surface condition than the skin layer formed on the upper mold side. Also, because the raw material is subjected to strong foaming pressure on the upper mold side, the density of the skin layer on the upper mold side is usually higher than that of the skin layer on the lower mold side. In contrast, using the method according to the present invention, not only is the surface condition of the skin layer on the lower mold good, but the surface condition of the skin layer on the upper mold is also better than that of conventional polyurethane foam. Furthermore, not only is the skin layer on the upper mold high-density, but the density of the skin layer on the lower mold is also high-density compared to conventional polyurethane foam.

[0031] [1.4. Overall (OA) Density] "Overall (OA) density" refers to the density of the entire soundproofing material. "Density" refers to the value measured in accordance with JIS K7222:2005.

[0032] Generally, the sound insulation performance of soundproofing materials increases as the mass per unit area increases. However, the soundproofing material according to the present invention exhibits high sound insulation performance despite being lightweight (low OA density) because it includes a double-wall structure region with a high density ratio. The soundproofing material according to the present invention has an OA density of 130 kg / m³ 3 It is less than . When manufacturing conditions are optimized, the OA density is 120 kg / m³. 3 Below 110kg / m 3 Below 100kg / m 3 Below 90kg / m 3 Below, or 80 kg / m 3 The following applies.

[0033] [1.5. Thickness] In the present invention, the double-wall structure region thickness t 0 teeth The thickness is not particularly limited, and the optimal thickness can be selected according to the purpose. t0 may be constant regardless of location, or it may vary depending on the location. However, if t0 becomes too thin, the sound insulation performance may decrease. Therefore, t0 is preferably 10 mm or more. More preferably, t0 is 20 mm or more, or 30 mm or more.

[0034] [1.6. Characteristics] [1.6.1. Average transmission loss] "Average transmission loss" refers to the average value of sound transmission loss in the frequency range of 400Hz to 4kHz. "Acoustic transmission loss" refers to the value measured in accordance with JIS A1441-1:2007.

[0035] The soundproofing material according to the present invention exhibits high sound insulation despite being lightweight, due to the inclusion of a double-wall structure region with a high density ratio. Optimizing the manufacturing conditions results in an average transmission loss of 15.0 dB or higher. Further optimization of the manufacturing conditions results in an average transmission loss of 16.0 dB or higher, 17.0 dB or higher, or 18.0 dB or higher.

[0036] [1.6.2. Breathability] "Skin layer region B" refers to the region defined when measuring air permeability, and includes the high-density region of the surface. Specifically, "skin layer B" refers to the region from the surface of the first skin layer or the surface of the second skin layer to a depth of 10.0 mm. "Core layer region B" refers to the region defined when measuring air permeability, and does not include the high-density region of the surface layer. Specifically, "core layer region B" refers to the region within ±5.0 mm from the center of the double-wall structure region. "Air permeability" refers to the value measured in accordance with JIS K6400-7:2012 Method A.

[0037] The thickness t0 of the double-wall structure region is not particularly limited, and the optimal thickness can be selected according to the purpose. However, in order to obtain high sound insulation, it is preferable that there is a large difference between the air permeability of the skin layer region B and the air permeability of the core layer region B. In order to increase the difference in air permeability, t0 is preferably 10 mm or more.

[0038] Air permeability Q of skin layer region B s This primarily affects the sound insulation properties of soundproofing materials. Generally, Q s The smaller Q is, the better the sound insulation. To achieve high sound insulation, Q s A flow rate of 12.0 L / min or less is preferable. s More preferably, the flow rate is 10.0 L / min or less, 8.0 L / min or less, or 6.0 L / min or less.

[0039] Air permeability Q of core layer region B c This primarily affects the sound absorption properties of soundproofing materials. Generally, Q cThe higher the value, the better the sound absorption. To achieve high sound absorption, Q c A flow rate of 15.0 L / min or higher is preferable. c More preferably, the flow rate is 20.0 L / min or more, 25.0 L / min or more, 30.0 L / min or more, or 35.0 L / min or more.

[0040] Furthermore, the breathability requirements for skin layer region B may be met on either the first skin layer side or the second skin layer side, or on both sides. Using the method described later, a soundproofing material can be obtained in which the breathability of skin layer region B, at least taken from the lower mold side, satisfies the above-mentioned conditions.

[0041] [1.6.3. Coefficient of Dynamic Friction] "Dynamic friction coefficient" refers to the value measured in accordance with JIS K7125.

[0042] The soundproofing material according to the present invention may be installed by being pressed into a narrow gap. Therefore, if the coefficient of dynamic friction on the surface of the soundproofing material becomes too high, it may become difficult to insert the soundproofing material into the gap. To facilitate the insertion of the soundproofing material, it is desirable for the coefficient of dynamic friction on the surface to be as low as possible.

[0043] The coefficient of dynamic friction can be controlled primarily by the type of raw materials used in the manufacture of polyurethane foam (especially low molecular weight polyols and low molecular weight amine compounds added as needed) and the type of release agent used in mold molding. To facilitate the insertion of soundproofing material, the coefficient of dynamic friction of the surface of the soundproofing material is preferably 0.9 or less. More preferably, the coefficient of dynamic friction is 0.7 or less, or 0.5 or less. The conditions for the coefficient of dynamic friction may be met by either the surface of the first skin layer or the surface of the second skin layer, or by both. To facilitate the insertion of soundproofing material into the gap, it is preferable that the conditions for the coefficient of dynamic friction be met by both the surface of the first skin layer and the surface of the second skin layer.

[0044] [2. Method for manufacturing soundproofing materials] The method for manufacturing soundproofing material according to the present invention is: A first step involves preparing a raw material mixture for the manufacture of polyurethane foam, which includes a polyol component, a polyisocyanate component, a catalyst, a blowing agent, and low molecular weight polyols. The second step involves applying a release agent to the inner surface of the mold, A third step involves injecting the raw material mixture into a mold coated with the release agent, foaming and hardening the raw material mixture within the mold, and obtaining the soundproofing material according to the present invention. It is equipped with.

[0045] [2.1. 1st step] First, a raw material mixture for the manufacture of polyurethane foam is prepared, containing a polyol component, a polyisocyanate component, a catalyst, a blowing agent, and low molecular weight polyols (Step 1). The raw material mixture may further contain low molecular weight amine compounds.

[0046] The soundproofing material according to the present invention is preferably a polyurethane foam having a three-dimensional crosslinked structure. A method for obtaining such a polyurethane foam is: (a) A method of reacting a raw material mixture containing a polyol having 3 or more functional groups and / or a polyisocyanate having 3 or more functional groups. (b) A method of reacting a raw material mixture in which both the polyol and polyisocyanate have 2 functional groups and the polyisocyanate is in excess, to produce a burette and / or allophanate in the polymer chain. These are some examples.

[0047] [2.1.1. Polyol components] "Polyol component" refers to one of the main raw materials for forming the polyurethane main chain, and means one type of polyol or a mixture containing two or more types of polyols. A "polyol" is a compound that has two or more hydroxyl groups in a single molecule. For forming the polyurethane main chain (main polyol), a polyol with a molecular weight of 500 or more is typically used. The type of polyol is not particularly limited, as long as it is capable of producing polyurethane foam that satisfies the above-mentioned conditions.

[0048] For example, the main polyol is (a) Those obtained by using a polyhydric alcohol as an initiator and adding ethylene oxide or propylene oxide to it (so-called "polyether polyols"), (b) Substances obtained by dehydrating and condensing a dibasic acid (e.g., a dicarboxylic acid) with a polyhydric alcohol (so-called "polyester polyols") (c) A polyether polyol in which polymer fine particles obtained by polymerizing a vinyl monomer (e.g., acrylonitrile or styrene) are dispersed (so-called "polymer polyols"). These are some examples. In this invention, one of these polyols may be used, or two or more may be used.

[0049] In particular, the polyol component is preferably one or more polyols having 2 to 4 functional groups and a weight-average molecular weight of 1,000 to 10,000. Furthermore, the polyol component may include polyols with a molecular weight of less than 1000 (for example, polyols with a molecular weight of about 600), as long as the weight-average molecular weight is within a predetermined range.

[0050] If the weight-average molecular weight of the polyol becomes too low, the polyurethane foam may become excessively rigid. Therefore, the weight-average molecular weight of the polyol is preferably 1000 or higher. More preferably, it is 1500 or higher, or even 2000 or higher. On the other hand, if the weight-average molecular weight becomes too high, the viscosity of the raw material mixture increases excessively. As a result, a high pump capacity is required in the manufacturing process. In addition, the mixability and fluidity of the raw material mixture may deteriorate. Therefore, the weight-average molecular weight of the polyol is preferably 10,000 or less. More preferably, the weight-average molecular weight is 9,000 or less, or 8,000 or less.

[0051] [2.1.2. Polyisocyanate components] "Polyisocyanate component" refers to one of the other main raw materials for forming the polyurethane main chain, and means one type of polyisocyanate or a mixture of two or more types of polyisocyanates. A "polyisocyanate" is a compound that has two or more isocyanate groups in a single molecule. The type of polyisocyanate is not particularly limited, as long as it is capable of producing polyurethane foam that satisfies the above-mentioned conditions.

[0052] As for polyisocyanates, (a) Aromatic isocyanate compounds, aliphatic isocyanate compounds, or alicyclic isocyanate compounds (b) Modified product of the above compound These are some examples.

[0053] Examples of aromatic isocyanate compounds include, Diphenylmethane diisocyanate (MDI), Crude diphenylmethane diisocyanate, tolylene diisocyanate (TDI), Naphthalene diisocyanate (NDI), p-phenylenediisocyanate (PPDI), xylenediisocyanate (XDI), Tetramethylxylene diisocyanate (TMXDI), Examples include toridine diisocyanate (TODI).

[0054] Examples of aliphatic isocyanate compounds include, Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), Examples include lysine triisocyanate (LTI).

[0055] Examples of alicyclic isocyanate compounds include, Isophorone diisocyanate (IPDI), Cyclohexyl diisocyanate (CHDI), Hydrogenated XDI (H6XDI), Hydrogenated MDI(H 12 Examples include MDI (Multi-Distributed Injection).

[0056] Examples of modified isocyanate compounds include urethane-modified, dimer-modified, trimer-modified, carbodiimide-modified, allophanate-modified, biuret-modified, urea-modified, isocyanurate-modified, oxazolidone-modified, and isocyanate-terminated prepolymers of isocyanate compounds.

[0057] [2.1.3. Catalyst] A "catalyst" refers to a catalyst that promotes a resin formation reaction, a catalyst that promotes a foaming reaction, or a catalyst that promotes both a resin formation reaction and a foaming reaction. Furthermore, if a chemical foaming agent (water) is not used as the foaming agent, it is not necessary to add a catalyst that promotes only the foaming reaction.

[0058] Examples of catalysts include amine-based catalysts and metal catalysts. Amine-based catalysts promote both the resinification reaction and the foaming reaction. Metal catalysts promote the resinification reaction. The raw material mixture may contain one of these catalysts, or two or more.

[0059] Examples of amine-based catalysts include, N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylaminoethanol, N,N',N'-trimethylaminoethylpiperazine, Triethylenediamine These are some examples.

[0060] Examples of metal catalysts include, (a) Tin catalysts such as stanus octoate and dibutylthin dilaurate, (b) Mercury catalysts such as phenylmercurypropionate, (c) Lead catalysts such as lead octonate These are some examples.

[0061] [2.1.4. Foaming agents] A "foaming agent" is an additive used to create bubbles in polyurethane. In the present invention, the foaming agent is (a) A physical foaming agent that generates gas by pressure reduction or heating, or (b) Chemical blowing agents that generate gas by thermal decomposition or chemical reaction Either of these is acceptable.

[0062] Examples of physical blowing agents include, (a) hydrocarbons such as cyclopentane, isopentane, and n-pentane, (b) Halogen compounds such as methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, pentafluoroethyl methyl ether, and pentafluoroisopropyl methyl ether. These are some examples.

[0063] Examples of chemical blowing agents include, (a) Water that reacts with an isocyanate group to produce CO2, (b) Azodicarbonamides that generate nitrogen, carbon monoxide, carbon dioxide, or ammonia gas by thermal decomposition. These are some examples.

[0064] The raw material mixture may contain one of these blowing agents, or it may contain two or more of them. Among these, water is preferred as the foaming agent. When water is used as the foaming agent, the CO2 gas generated by the reaction of water with isocyanate groups promotes foaming. In addition, the reaction between water and isocyanate groups forms urea bonds and urea bonds, promoting resin formation.

[0065] [2.1.5. Low Molecular Weight Polyols] "Low molecular weight polyols" refers to polyols that are different from polyol components and have a molecular weight of less than 500. The number of functional groups in low molecular weight polyols is preferably 2 to 6. Preferably, the number of functional groups is 2 to 4, and more preferably 2 to 3. The molecular weight of the low molecular weight polyol is preferably 300 or less. Preferably, the molecular weight is 200 or less, and more preferably 150 or less. The hydroxyl value of low molecular weight polyols is preferably 400 mg KOH / g or higher. Preferably, the hydroxyl value is 600 mg KOH / g or higher, 800 mg KOH / g or higher, or 1000 mg KOH / g or higher.

[0066] Examples of low molecular weight polyols include, (a) Ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BG), 1,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, (b) Trimethylolpropane, glycerin, sorbitol, quadrol, These are some examples. The raw material mixture may contain one of these low molecular weight polyols, or it may contain two or more.

[0067] Low molecular weight polyols function as chain extenders. Furthermore, if the molecular structure of the low molecular weight polyols is branched, or if the raw material mixture contains components with three or more functional groups, the low molecular weight polyols also function as crosslinking agents that crosslink polymer chains. Adding a relatively large amount of low molecular weight polyols to the raw material mixture allows for the production of polyurethane foam with a high density ratio and low density. In particular, the density of the skin layer on the lower mold side becomes higher than that of conventional polyurethane foam. This is thought to be because the addition of a large amount of low molecular weight polyols to the raw material mixture initiates the resinification reaction from the early stages of the reaction, and foam growth in the region near the lower mold is suppressed by resinification.

[0068] [2.1.6. Low molecular weight amine compounds] "Low molecular weight amine compounds" are, (a) Compounds having a hydroxyl group (-OH) and an amino group (-NH2, -NHR, -NRR') on an alkane skeleton (alkanolamines), or (b) Compounds having two or more amino groups (-NH2, -NHR, -NRR') It refers to. The number of functional groups in the low molecular weight amine compound is preferably 2 to 6. More preferably, the number of functional groups is 2 to 4, and even more preferably, 2 to 3. Furthermore, the molecular weight of the low-molecular-weight amine compound is preferably 200 or less. More preferably, the molecular weight is 150 or less.

[0069] Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-(2-aminoethylamino)ethanol, 2-amino-2-hydroxymethyl-1,3-propanediol, ethylaminoethanol, and aminobutanol. Examples of compounds with two or more amino groups include ethylenediamine. The raw material mixture may contain one of these, or it may contain two or more of these.

[0070] Low molecular weight amine compounds function as chain extenders or amine catalysts. Furthermore, if the molecular structure of the low molecular weight amine compound is branched, or if the raw material mixture contains components with three or more functional groups, the low molecular weight amine compound can also function as a crosslinking agent, bridging polymer chains. Low molecular weight amine compounds are not always necessary. However, adding low molecular weight amine compounds to the raw material mixture further accelerates the resinification reaction, making it easier to produce polyurethane foam with a high density ratio and low density.

[0071] [2.1.6. Other Ingredients] The raw material mixture for the manufacture of polyurethane foam may contain other components in addition to the components listed above. These other components may include, for example, foam stabilizers, foam breakers, flame retardants, and colorants. The raw material mixture may contain one or more of these other components.

[0072] [A. Foam stabilizer] A "foam stabilizer" is an additive that helps to equalize the size and distribution of bubbles. By adding a foam stabilizer to the raw material mixture, a soundproofing material with uniform bubble size and distribution can be obtained. Examples of foam stabilizers include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, and known surfactants.

[0073] [B. Antifoaming agent] A "defoaming agent" is an additive that has the effect of connecting closed cells, and is also called a "cell opener." When a raw material mixture is foamed, if there are closed cells in the polyurethane foam, the cells will contract during the cooling process, and the soundproofing material will also contract accordingly. In contrast, by adding a foam-breaking agent to the raw material mixture, the cells will become interconnected, reducing the number of closed cells and suppressing the contraction of the soundproofing material during the cooling process. Examples of foam-breaking agents include hydrocarbon-based foam-breaking agents, ester-based foam-breaking agents, silicone-based foam-breaking agents, and polyol-based foam-breaking agents.

[0074] Examples of hydrocarbon-based antifoaming agents include oils such as polybutene. Examples of ester-based antifoaming agents include dimer acid diesters. Examples of silicone-based antifoaming agents include cyclopentasiloxane. Examples of polyol-based antifoaming agents include polyether polyols having an EO ratio of 50% or more (preferably 60-100%).

[0075] [C. Flame retardant] A "flame retardant" is an additive that makes soundproofing materials flame-retardant. By adding a flame retardant to the raw material mixture, soundproofing materials can be made flame-retardant. Examples of flame retardants include: (a) Phosphorus-based flame retardants, powder flame retardants such as ammonium polyphosphate, (b) Liquid flame retardants such as phosphate ester flame retardants These are some examples.

[0076] [D. Colorants] A "coloring agent" refers to an additive that has the effect of coloring soundproofing materials to a desired color. By adding a coloring agent to the raw material mixture, soundproofing materials can be colored to the desired color. Examples of coloring agents include carbon black.

[0077] [2.1.7. Content of each component] [A. Isocyanate Index] The "isocyanate index" is the value obtained by multiplying the ratio of the equivalent amount of isocyanate groups in the polyisocyanate in the raw material mixture to the equivalent amount of active hydrogen groups in the raw material mixture by 100.

[0078] If the isocyanate index becomes too low, the strength of the polyurethane foam may become excessively low, potentially reducing its durability. Furthermore, during the cooling process after foaming, gas may not escape easily from the bubbles, potentially causing the soundproofing material to shrink. Therefore, an isocyanate index of 80 or higher is preferable. More preferably, the isocyanate index is 85 or higher, or even 90 or higher. On the other hand, if the isocyanate index becomes too high, the polyurethane foam may become excessively rigid, making it difficult for the soundproofing material to deform according to the shape of the mating surface. Therefore, an isocyanate index of 120 or less is preferable. More preferably, the isocyanate index is 115 or less, or 110 or less.

[0079] [B. Catalyst content] "Catalyst content" refers to the weight of the catalyst (parts per hundred parts of polyol, pphp) relative to the weight of the polyol component, which is set to 100.

[0080] Generally, the higher the catalyst content, the faster the reaction proceeds. To obtain this effect, a catalyst content of 0.1 pphp or more is preferable. More preferably, the content is 0.5 pphp or more, or 1.0 pphp or more. On the other hand, if the catalyst content is excessive, the polyurethane foam may become excessively hard. Therefore, the catalyst content is preferably 8.0 pphp or less. More preferably, the content is 6.0 pphp or less, or 4.0 pphp or less.

[0081] [C. Foaming agent content] "Foaming agent content" refers to the weight of the foaming agent (pphp) relative to the weight of the polyol component, which is set to 100.

[0082] It is preferable to select the optimal amount of foaming agent depending on the type of foaming agent. For example, when the foaming agent is water, generally, the higher the water content, the lower the OA density of the soundproofing material that can be obtained. To obtain a low-density soundproofing material, a water content of 1.0 pphp or more is preferable. A content of 2.0 pphp or more, or even 3.0 pphp or more, is more preferable. On the other hand, if the water content is excessive, the OA density may decrease excessively, and the strength of the soundproofing material may decrease. Therefore, the water content is preferably 10.0 pphp or less. More preferably, the content is 8.0 pphp or less, or 6.0 pphp or less.

[0083] [D. Content of low molecular weight polyols] "Low molecular weight polyol content" refers to the weight of low molecular weight polyols (pphp) when the weight of the polyol component is set to 100.

[0084] Generally, the higher the content of low molecular weight polyols, the easier it is for a skin layer region with a high density ratio to form on the surface. To obtain this effect, the content of low molecular weight polyols is preferably 1.5 pphp or more. More preferably, the content is 2.0 pphp or more, or 3.0 pphp or more. On the other hand, because low molecular weight polyols do not contain amino groups, polyurethane foam is less likely to become excessively hard compared to low molecular weight amine compounds. However, if the content of low molecular weight polyols is excessive, the polyurethane foam may become excessively hard. Therefore, the content of low molecular weight polyols is preferably 10.0 pphp or less. More preferably, the content is 7.0 pphp or less.

[0085] [E. Low molecular weight amine compound content] "Low molecular weight amine compound content" refers to the weight (pphp) of the low molecular weight amine compound when the weight of the polyol component is set to 100.

[0086] In the present invention, the content of the low molecular weight amine compound may be zero. Generally, the higher the content of the low molecular weight amine compound, the easier it is to form a skin layer region with a high density ratio on the surface. To obtain such an effect, the content of the low molecular weight amine compound is preferably greater than 0 pphp. More preferably, the content is 0.4 pphp or more, or 0.8 pphp or more.

[0087] On the other hand, the amino group of the low molecular weight amine compound also functions as a catalyst for the urethane reaction. Therefore, if the content of the low molecular weight amine compound is excessive, the polyurethane foam may become excessively hard. If the polyurethane foam becomes too hard, it may become difficult to insert soundproofing material into the voids. For this reason, the content of the low molecular weight amine compound is preferably 2.0 pphp or less. More preferably, the content is 1.6 pphp or less, or 1.2 pphp or less.

[0088] [F. Content of other ingredients] The content of other ingredients is not particularly limited, and the optimal amount can be selected according to the purpose.

[0089] [2.2. 2nd process] Next, a release agent is applied to the inner surface of the mold (second step).

[0090] The shape of the mold is not particularly limited, and the optimal shape can be selected according to the purpose. Typically, a split mold that can be separated into upper and lower halves is used. In addition, heating means such as electric heaters and heat transfer pipes are usually embedded in the mold to maintain the mold at a predetermined temperature.

[0091] The type of release agent affects the breathability of the skin layer. In this invention, the release agent used contains a wax component having two melting peaks and a branched chain structure. This is different from conventional methods.

[0092] Release agents, in particular, (a) A first wax component having a first melting peak between 70°C and 90°C and a branched chain structure, (b) A second wax component having a second melting peak between 100°C and 130°C and a branched chain structure It is preferable that it contains [the specified ingredient]. The first wax component is preferably one with a weight-average molecular weight of 600 or less. The second wax component is preferably one with a weight-average molecular weight of 1000 or more.

[0093] When molding polyurethane foam, release agents not only facilitate the removal of the molded product from the mold, but also suppress the formation of air bubbles near the mold surface. Therefore, applying a release agent to the mold surface during molding allows for the formation of a high-density skin layer on the surface of the molded product. However, if the type of release agent is not appropriate, open pores may form on the surface of the skin layer, cell roughness may occur, or the density of the skin layer on the lower mold side may be reduced. In contrast, using a release agent that satisfies the above conditions makes it possible to form a skin layer on the surface with fewer open pores and cell roughness. Furthermore, the density of the skin layer on the lower mold side, as well as the upper mold side, becomes higher.

[0094] The method of applying the release agent is not particularly limited, and the most suitable method can be selected according to the purpose. Application methods include brush application and spray application. Furthermore, the amount of release agent applied is not particularly limited, and the optimal amount can be selected according to the purpose. Typically, the application amount is 10 mg / m². 2 ~100g / m 2 It is to that extent.

[0095] [2.3. Third step] Next, the raw material mixture is injected into a mold coated with a release agent, and the raw material mixture is foamed and hardened inside the mold (third step). This yields the soundproofing material according to the present invention.

[0096] The raw material mixture is poured into a mold heated to a predetermined temperature. In this case, if the mold temperature is too low, the curing of the raw material mixture will take a long time, which may reduce productivity. Also, the foaming of the raw material mixture may be insufficient, and the mold cavity may not be completely filled with polyurethane foam. Therefore, the mold temperature is preferably 40°C or higher. More preferably, the mold temperature is 50°C or higher.

[0097] On the other hand, if the mold temperature becomes too high, the reactivity of the raw material mixture may become too high, resulting in poor flowability of the mixture. Also, some of the release agent may melt excessively, causing the surface of the molded product to become rough. Therefore, the mold temperature is preferably 80°C or lower. More preferably, the mold temperature is 70°C or lower. After a predetermined time has elapsed, the soundproofing material is removed from the mold.

[0098] [3. Effect] When a mold release agent is applied to a mold, a raw material mixture for polyurethane foam manufacturing is injected into the mold, and the raw material mixture is foamed and cured inside the mold, the mold release agent suppresses the generation of air bubbles on the mold surface. As a result, a soundproofing material is obtained that includes a double-wall structure region consisting of a first skin layer / core layer / second skin layer. In this case, if low molecular weight polyols, or low molecular weight polyols and low molecular weight amine compounds are added to the raw material mixture, and a mold release agent containing a wax component with two melting peaks and a branched chain structure is used, a low-density soundproofing material with excellent sound absorption and sound insulation properties can be manufactured at low cost.

[0099] The soundproofing material according to the present invention exhibits high sound insulation performance despite being lighter than conventional polyurethane soundproofing materials. This is because, (A) By adding low molecular weight polyols, or low molecular weight polyols and low molecular weight amine compounds, to the raw material mixture, the density ratio of the first skin layer region A and the density ratio of the second skin layer region A increased, further improving the sound insulation effect of the double wall, and (B) By using a release agent containing a wax component with two melting peaks and a branched chain structure, the formation of open pores and cell roughness on the surface of the skin layer is suppressed, and the sound insulation effect of the double wall is further improved. It is thought that... [Examples]

[0100] (Examples 1-16, Comparative Examples 1-5) [1. Sample Preparation] [1.1. Raw materials] The following polyols were used: (1) Polyol A: Polyether polyol, molecular weight 7000, number of functional groups 3, EO content 14%, product name: KC-737, manufactured by Sanyo Chemical Industries, Ltd. (2) Polyol B: Polyether polyol, molecular weight 5000, number of functional groups 3, EO content 14%, product name: FA-703, manufactured by Sanyo Chemical Industries, Ltd. (3) Polyol C: Polymer polyol, molecular weight 5000, number of functional groups 3, product name: FA-728R, manufactured by Sanyo Chemical Industries, Ltd.

[0101] The following catalysts were used: (1) Catalyst A: Amine catalyst, product name: DABCO BL-11, manufactured by Evonik. (2) Catalyst B: Amine catalyst, product name: DABCO 33LSI, manufactured by Evonik. (3) Catalyst C: Amine catalyst, Product name: TOYOCAT D-60, manufactured by Tosoh Corporation

[0102] The following were used as crosslinking agents (alkanolamines or low molecular weight polyols): (1) Crosslinking agent A: Diethanolamine, molecular weight 105, number of functional groups 2, hydroxyl value 1603 mgKOH / g (2) Crosslinking agent B: Ethylene glycol (EG), molecular weight 62, number of functional groups 2, hydroxyl value 1810 mgKOH / g (3) Crosslinking agent C: Diethylene glycol (DEG), molecular weight 106, number of functional groups 2, hydroxyl value 1059 mgKOH / g (4) Crosslinking agent D: 1,4-butanediol, molecular weight 90, number of functional groups 2, hydroxyl value 1245 mgKOH / g

[0103] The following were used as the foam stabilizer, foam breaker, and foaming agent, respectively. (1) Foam stabilizer: Silicone foam stabilizer, product name: B8738LF2, manufactured by Evonik. (2) Antifoaming agent: Polyether polyol, molecular weight 4800, number of functional groups 3, PO / EO = 30 / 70 (EO ratio 70%), product name: CP1421, manufactured by Dow Chemical Company. (3) Foaming agent: Water

[0104] The following polyisocyanates were used: (1) Polyisocyanate A: Polymeric MDI, NCO%: 31.5%, Product name: 600B, manufactured by BASF INOAC Polyurethane Co., Ltd. (2) Polyisocyanate B: Polymeric MDI, NCO%: 27.0%, Product name: M249, manufactured by Sumika Covestro Urethane Co., Ltd. (3) Polyisocyanate C: A 50 / 50 mixture of TDI-80 and polymeric MDI, NCO%: 31.5%, Product name: TM50, manufactured by Mitsui Chemicals, Inc.

[0105] The following were used as release agents. (1) 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. (2) Release agent B: Branched wax-based release agent, melting peak 106.9℃, product name: M975, manufactured by Chukyo Oils Co., Ltd. (3) Release agent C: Linear wax-based release agent, first melting peak 93.2°C, second melting peak 108.3°C, product name: T-626, manufactured by Chukyo Oils Co., Ltd.

[0106] Table 1 shows the composition of the raw materials used. Table 1 also includes the OA density of each sample and the type of release agent used during mold molding.

[0107] [Table 1]

[0108] [1.2. Molding] For foam molding, (a) The mold is divided into an upper and lower section, and the inner surface shape of the mold is a rectangular parallelepiped, with inner surface dimensions of 500 × 500 × t20 mm (mold volume: 5000 cm²). 3 ) a mold, and (b) The mold is divided into an upper and lower section, and the inner surface shape of the mold is a rectangular parallelepiped, with inner surface dimensions of 500 × 250 × t40 mm (mold volume: 5000 cm³) 3 ) is a mold I used it.

[0109] A release agent was sprayed onto the inner surface of the mold. The amount applied was approximately 25 g / m². 2 The process involved pouring a predetermined amount of raw material mixture into a mold maintained at 60°C, and allowing the mixture to foam and harden within the mold. After a predetermined time, the mold was demolded to obtain polyurethane foam.

[0110] [2. Test Method] [2.1. OA density] A 500 x 250 x t40 mm polyurethane foam sample was used for OA density measurement. The OA density of the sample was measured in accordance with JIS K7222:2005.

[0111] [2.2. Upper mold surface density, core density, lower mold surface density] A 500 x 250 x 40 mm thick polyurethane foam was cut into a rectangular prism measuring 51 mm square x 40 mm thick. Next, the rectangular prism was sliced ​​parallel to its top and bottom surfaces, and sheets measuring 51 mm square x 5 mm thick were obtained from the upper die-side surface region, the central region, and the lower die-side surface region of the rectangular prism.

[0112] Using these sheets, in accordance with JIS K7222:2005, (A) Upper mold surface density (density of the first skin layer region A) ρ s1 , (B) Core density (density of core layer region A) ρ c, and, (C) Lower mold surface density (density of the second skin layer region A) ρ s2 We measured it. Furthermore, using the obtained density, (A) Density ratio of the upper mold surface layer (density ratio of the first skin layer A) ρ s1 / ρ c , and, (B) Lower mold surface density ratio (density ratio of the second skin layer A) ρ s2 / ρ c The result was calculated.

[0113] [2.3. Breathability] 500 x 250 x t4 0mm Polyurethane foam was cut into a rectangular prism measuring 51 mm square x 40 mm thick. Next, the rectangular prism was sliced ​​parallel to its top and bottom surfaces, and sheets measuring 51 mm square x 10 mm thick were obtained from the central region and the lower surface region of the rectangular prism. Using these sheets, in accordance with JIS K6400-7:2012 Method A, (A) Air permeability of the inner core layer (air permeability of core layer region B) Q c , and, (B) Air permeability of the surface skin (air permeability of skin layer region B) Q s We measured it.

[0114] [2.4. Sound Insulation] A 400mm x 400mm opening was formed in the center of a 500 x 500 x t20mm polyurethane foam. This was used to evaluate sound insulation performance in accordance with JIS A1441-1:2007. Acoustic transmission loss was measured in a 1 / 3 octave band, and the average acoustic transmission loss (average transmission loss) at frequencies from 400Hz to 4kHz was determined.

[0115] [2.5. Coefficient of Dynamic Friction] A 500 x 250 x 40 mm thick polyurethane foam was cut into a rectangular prism measuring 63 mm square x 40 mm thick. Next, the rectangular prism was sliced ​​parallel to its top and bottom surfaces, and a sheet measuring 63 mm square x 10 mm thick was obtained from the lower surface area of ​​the rectangular prism. The coefficient of dynamic friction was measured using this sheet in accordance with JIS K7125.

[0116] [3. Results] The results are shown in Table 2. Figure 1 shows the measurement results of the sound transmission loss of the soundproofing materials obtained in Examples 1-3, Comparative Example 1, and Comparative Example 5. From Table 2 and Figure 1, the following can be seen.

[0117] Note that in Table 2, the density ratio (ρ s1 / ρ c ρ s2 / ρ c Regarding the above, "◎" indicates a density ratio of 1.10 or higher, "○" indicates a density ratio of 1.08 or higher but less than 1.10, "△" indicates a density ratio of 1.05 or higher but less than 1.08, and "×" indicates a density ratio of less than 1.05.

[0118] Breathability of the surface skin (Q s Regarding the above, "◎" indicates that the air permeability is 4.0 L / min or less, "○" indicates that the air permeability is greater than 4.0 L / min but 8.0 L / min or less, "△" indicates that the air permeability is greater than 8.0 L / min but 12.0 L / min or less, and "×" indicates that the air permeability is greater than 12.0 L / min.

[0119] The difference in air permeability between the surface layer and the inner core layer (ΔQ = Q) c -Q s Regarding the above, "◎" indicates that the difference in air permeability is 20.0 L / min or more, "○" indicates that the difference in air permeability is 15.0 L / min or more but less than 20.0 L / min, and "△" indicates that the difference in air permeability is less than 15.0 L / min.

[0120] Regarding sound insulation, "◎" indicates an average transmission loss of 16.0 dB or more, "○" indicates an average transmission loss of 12.0 dB or more but less than 16.0 dB, "△" indicates an average transmission loss of 8.0 dB or more but less than 12.0 dB, and "×" indicates an average transmission loss of less than 8.0 dB.

[0121] (1) Comparative Example 1 had an average transmission loss of 14.3 dB. Also, Comparative Example 1 had a lower surface density ratio ρ s2 / ρ c The value was 1.04. This is thought to be because the raw material mixture does not contain low molecular weight polyols. (2) Comparative Example 2 had an average transmission loss of 10.9 dB. In addition, Comparative Example 2 had a surface skin layer air permeability Q s The flow rate increased to 26.9 L / min. This is thought to be because the raw material mixture did not contain low molecular weight polyols and the release agent was inappropriate.

[0122] (3) Comparative Example 3 had an average transmission loss of 7.5 dB. Also, Comparative Example 3 had a lower mold side surface density ratio ρ s2 / ρ c The value was 1.04. Furthermore, in Comparative Example 3, the breathability Q of the surface skin layer was s The flow rate increased to 14.7 L / min. This is thought to be because the raw material mixture did not contain low molecular weight polyols and the release agent was inappropriate. (4) Comparative Example 4 showed good sound insulation with an average transmission loss of 20.9 dB. However, the OA density of Comparative Example 4 was 150 kg / m³. 3 It increased to a low level in the raw material mixture. molecular weight This is likely because it does not contain polyols and the amount of diethanolamine is relatively excessive.

[0123] (5) Comparative Example 5 showed good sound insulation with an average transmission loss of 15.8 dB. However, the OA density of Comparative Example 5 was 150 kg / m³. 3 It increased to ρ. Also, the surface density ratio ρ of the lower mold in Comparative Example 5 s2 / ρ c The value was 1.03. This indicates a low concentration in the raw material mixture. molecular weight This is thought to be because the product did not contain polyols, the amount of diethanolamine was relatively excessive, and the release agent was inappropriate. (6) Examples 1 to 16 all have an OA density of 80 kg / m³. 3 The following results were obtained, with an average transmission loss of 16.0 dB or higher. This is thought to be due to the relatively large amount of low molecular weight polyols contained in the raw material mixture, and the use of an appropriate release agent.

[0124] [Table 2]

[0125] Although embodiments of the present invention have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Industrial applicability]

[0126] The soundproofing material according to the present invention is (a) Soundproofing material inserted into the gaps surrounding the fenders, instrument panel, cowl, dash silencer, floor silencer, etc. of an automobile. (b) Soundproofing material to cover the area around noisy components such as motors and compressors. It can be used for things like this.

Claims

1. The polyurethane foam comprises a double-wall structure region consisting of a first skin layer / core layer / second skin layer, The density ratio of the first skin layer region A is 1.05 or higher. The density ratio of the second skin layer region A is 1.05 or higher. Overall (OA) density is 130 kg / m³ 3 Less than Soundproofing material. however, The aforementioned "density ratio of the first skin layer region A" refers to the density of the core layer region A (ρ c The density of the first skin layer region A relative to (ρ s1 The ratio of (=ρ) s1 / ρ c ) refers to, The "density ratio of the second skin layer region A" refers to the density (ρ c ) of the second skin layer region A with respect to the density (ρ s2 ) of the core layer region A (= ρ s2 / ρ c ), and The aforementioned "core layer region A" is defined as ±t from the center of the double-wall structure region. A This refers to the region of / 2. The "first skin layer region A" refers to the region from the surface of the first skin layer side of the double-wall structure region to a depth t. A This refers to the area up to that point. The aforementioned "second skin layer region A" refers to the region from the surface of the second skin layer side of the double-wall structure region to a depth t. A This refers to the area up to that point. t A = 5.0 mm, or t 0 × 0.125 (t 0 (This is the thickness of the double-wall structure region.)

2. The soundproofing material according to claim 1, wherein the average transmission loss is 15.0 dB or more. however, The aforementioned "average transmission loss" refers to the average value of the sound transmission loss in the frequency range of 400 Hz to 4 kHz. The aforementioned "acoustic transmission loss" refers to the value measured in accordance with JIS A1441-1:2007.

3. The soundproofing material according to claim 1, wherein the air permeability of the skin layer region B is 12.0 L / min or less. however, The aforementioned "skin layer region B" refers to the region from the surface on the first skin layer side or the surface on the second skin layer side to a depth of 10.0 mm. The aforementioned "air permeability" refers to the value measured in accordance with JIS K6400-7:2012 Method A.

4. A first step involves preparing a raw material mixture for the manufacture of polyurethane foam, which includes a polyol component, a polyisocyanate component, a catalyst, a blowing agent, and low molecular weight polyols. The second step involves applying a release agent to the inner surface of the mold, A third step involves injecting the raw material mixture into a mold coated with the release agent, foaming and hardening the raw material mixture within the mold, and obtaining the soundproofing material described in claim 1. Equipped with, The mold release agent contains a wax component having two melting peaks and a branched chain structure. A method for manufacturing soundproofing materials. However, the term "low molecular weight polyols" refers to polyols that are different from the aforementioned polyol components and have a molecular weight of less than 500.

5. The method for producing a soundproofing material according to claim 4, wherein the raw material mixture further comprises a low molecular weight amine compound.

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