Sound insulation material and manufacturing method thereof

Abstract

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

Description

Technical Field

[0001] The present invention relates to a sound insulating material and a method for manufacturing the same. More specifically, the present invention relates to a sound insulating material containing polyurethane foam, having excellent sound absorption and sound insulation properties, and a low density, and a method for manufacturing the same. Background Art

[0002] Polyurethane refers to a polymer compound having a urethane bond (-NH-C(O)O-). Polyurethane is generally obtained by reacting the hydroxyl group (-OH) of a polyol with the isocyanate group (-NCO) of a polyisocyanate. It is known that polyurethane exhibits various properties by optimizing the types of polyol and / or polyisocyanate. Therefore, polyurethane is applied to various automotive parts, synthetic leather, coatings, adhesives, etc. In addition, polyurethane foam obtained by foaming polyurethane is applied to heat insulating materials, cushioning materials, etc.

[0003] Polyurethane foam is roughly classified into:

[0004] (a) Soft polyurethane foam with interconnected cells;

[0005] (b) Rigid polyurethane foam with independent cells; and

[0006] (c) Semi-rigid polyurethane foam having intermediate properties between rigid and soft.

[0007] Among these, it is known that soft polyurethane foam exhibits sound absorption properties. When sound is incident on soft polyurethane foam, the sound enters the interconnected cells, and the sound is reflected in various directions within the interconnected cells. At this time, viscous friction of air is generated on the inner surface of the interconnected cells. As a result, a part of the sound energy is converted into heat energy due to the friction, and the sound is attenuated. Therefore, soft polyurethane foam is used as, for example, a sound insulating material in voids that become sound transmission paths in an automobile (for example, voids existing in fenders, instrument panels, and around engine hoods).

[0008] Regarding such sound insulating materials, various proposals have been made.

[0009] For example, Patent Documents 1 and 2 disclose a sound insulating material obtained by reacting raw materials containing the following components:

[0010] (a) Polyether polyol having a functionality of 3 and a molecular weight of 5000: 90 parts by mass,

[0011] (b) Polymer polyol having a functionality of 3 and a molecular weight of 5000: 10 parts by mass,

[0012] (c) Diethanolamine (crosslinking agent): 1 part by mass,

[0013] (d) Amine catalyst: 0.95 parts by mass,

[0014] (e) Water (foaming agent): 1.3 parts by mass,

[0015] (f) Silicone foam stabilizer: 0.17 parts by mass, and

[0016] (g) Modified 4,4'-diphenylmenthane diisocyanate: 41.7 parts by mass (equivalent to isocyanate index = 100).

[0017] It is described in this document that a sound insulation material can be obtained by using this method.

[0018] (A) Having a covering layer on the surface;

[0019] (B) The dynamic friction coefficient of the covering layer surface is 0.762;

[0020] (C) The surface hardness of the covering layer is 2 based on the ASKER C hardness meter;

[0021] (D) The air permeability of the surface is 7 L / min;

[0022] (E) The air permeability inside is 23 L / min;

[0023] (F) The density is 135 kg / m 3 .

[0024] Patent Document 3 discloses a sound insulation material obtained by reacting raw materials containing the following components:

[0025] (a) A polyol having a functionality of 4 or 5 and an average molecular weight of 500 to 600;

[0026] (b) A polyol having a functionality of 2 or 3 and an average molecular weight of 3000 to 4000;

[0027] (c) MDI-based isocyanate;

[0028] (d) Tertiary amine (catalyst); and

[0029] (e) Water (foaming agent).

[0030] It is described in this document that a sound insulation material can be obtained by using this method.

[0031] (A) The Young's modulus is 1.6×10 5 N / m 2 ;

[0032] (B) The density is 104 kg / m 3 ,

[0033] (C) Air permeability resistance is 3000 Ns / m 3 .

[0034] For sound insulation materials, not only high sound absorption but also high sound insulation (large transmission loss) is required. In order to increase the transmission loss, it is necessary to increase the density of the sound insulation material and increase the thickness of the sound insulation material. In a sound insulation material containing polyurethane foam, a high-density skin layer is provided on the surface, thereby performing an operation of imparting sound insulation. However, the sound insulation of conventional sound insulation materials containing polyurethane foam is insufficient.

[0035] On the other hand, if the density of the skin layer is further increased or the thickness of the skin layer is increased in order to improve the sound insulation, the weight of the sound insulation material increases, which runs counter to the demand for lightweight.

[0036] In addition, when molding polyurethane foam, if a mold release agent is applied to the surface of the mold, a stronger skin layer can be formed on the surface of the molded product. However, if the type of the mold release agent is inappropriate, when reducing the overall density of the polyurethane foam, open pores sometimes form on the surface of the skin layer. If open pores form on the surface of the skin layer, the sound insulation of the sound insulation material decreases.

[0037] On the other hand, if a general mold release agent that is not likely to form open pores is used, sometimes the cell unevenness occurs on the surface, and the sound insulation of the sound insulation material decreases.

[0038] To solve this problem, the following methods etc. can be considered:

[0039] (A) A method of flowing a polyurethane raw material onto the surface of a film and integrally molding the film and the polyurethane foam;

[0040] (B) A method of spraying a coating onto the cavity surface of a mold to form a surface layer, and then flowing a polyurethane raw material into the mold and integrally molding the surface layer and the polyurethane foam (so-called "molding coating method").

[0041] However, the shape followability of the sound insulation material containing a film is poor. Therefore, wrinkles sometimes form on the surface of the sound insulation material, and the sealing performance deteriorates. In addition, in the molding coating method, the periphery of the mold is easily soiled by the coating. Furthermore, these methods all increase the cost of the sound insulation material.

[0042] Prior art documents

[0043] Patent documents

[0044] Patent document 1: Japanese Patent Application Laid-Open No. 2013-246182 (Japanese Patent No. 6137783)

[0045] Patent document 2: Japanese Patent Application Laid-Open No. 2017-142532 (Japanese Patent No. 6352491)

[0046] Patent Document 3: Japanese Patent Application Laid-Open No. 2006-195055 (Japanese Patent No. 4757498) Summary of the Invention

[0047] Problems to be Solved by the Invention

[0048] The problem to be solved by the present invention is to provide a sound insulation material that includes a polyurethane foam, has excellent sound absorption and sound insulation properties, and has a low density.

[0049] In addition, another problem that the present invention aims to solve is to provide a method for manufacturing a sound insulation material that can manufacture such a sound insulation material at low cost.

[0050] Solutions to the Problems

[0051] To solve the above problems, the sound insulation material according to the present invention includes a polyurethane foam, and the polyurethane foam includes a double-wall structure region composed of a first skin layer / core layer / second skin layer.

[0052] The density ratio of the first skin layer region A is 1.05 or more.

[0053] The density ratio of the second skin layer region A is 1.05 or more.

[0054] The overall (OA) density of the sound insulation material is less than 130 kg / m 3 .

[0055] The method for manufacturing the sound insulation material according to the present invention includes:

[0056] A first step of preparing a raw material mixture for manufacturing a polyurethane foam including a polyol component, a polyisocyanate component, a catalyst, a foaming agent, and low molecular weight polyols;

[0057] A second step of coating a mold release agent on the inner surface of a mold; and

[0058] A third step of injecting the aforementioned raw material mixture into the mold coated with the aforementioned mold release agent, foaming and curing the aforementioned raw material mixture in the aforementioned mold to obtain the sound insulation material according to the present invention.

[0059] The aforementioned mold release agent includes a wax component having two melting peaks and a branched structure.

[0060] The aforementioned raw material mixture may further include a low molecular amine compound.

[0061] Effects of the Invention

[0062] If a mold is coated with a mold release agent, and a raw material mixture for producing a polyurethane foam is poured into the mold, and the raw material mixture is foamed and cured in the mold, the mold release agent will inhibit the generation of bubbles on the mold surface. As a result, a sound insulation material including a double-wall structure region composed of a first skin layer / core layer / second skin layer can be obtained. In this case, if a low molecular weight polyol or a low molecular weight polyol and a low molecular amine compound are added to the raw material mixture, and a substance containing a wax component having two melting peaks and a branched structure is used as the mold release agent, a sound insulation material excellent in sound absorption and sound insulation properties and having a low density can be produced at low cost.

[0063] Although the sound insulation material of the present invention is lighter in mass than a conventional polyurethane sound insulation material, it still exhibits high sound insulation properties. It is considered that this is because:

[0064] (A) By adding a low molecular weight polyol or a low molecular weight polyol and a low molecular weight amine compound to the raw material mixture, the density ratios of the first skin layer region A and the second skin layer region A increase, and the sound insulation effect achieved by the double wall is further improved; and

[0065] (B) By using a substance containing a wax component having two melting peaks and a branched structure as the mold release agent, the formation of open pores and cell non-uniformity on the surface of the skin layer is inhibited, and the sound insulation effect achieved by the double wall is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a graph showing the measurement results of the sound transmission loss of the sound insulation materials obtained in Examples 1 to 3, Comparative Example 1, and Comparative Example 5. DETAILED DESCRIPTION

[0067] Hereinafter, an embodiment of the present invention will be described in detail.

[0068] [1. Sound Insulation Material]

[0069] The sound insulation material of the present invention has the following constitution.

[0070] (1) The aforementioned sound insulation material contains a polyurethane foam.

[0071] (2) The aforementioned sound insulation material has a double-wall structure region composed of a first skin layer / core layer / second skin layer at least in a part thereof,

[0072] The density ratio of the first skin layer region A is 1.05 or more,

[0073] The density ratio of the second skin layer region A is 1.05 or more.

[0074] (3) The overall (OA) density of the aforementioned sound insulation material is less than 130 kg / m3 。

[0075] [1.1. Material]

[0076] The sound insulation material described in the present invention contains polyurethane foam. The polyurethane foam constituting the sound insulation material preferably has a three-dimensional crosslinked structure.

[0077] Examples of the polyurethane foam having a three-dimensional crosslinked structure include the following foams:

[0078] (a) A foam 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;

[0079] (b) A foam obtained by reacting a raw material mixture in which both the polyol and the polyisocyanate have 2 functional groups and the polyisocyanate is in excess, and forming biuret and / or urethane in the polymer chain.

[0080] The polyurethane foam constituting the sound insulation material is not particularly limited as long as it satisfies the conditions described below.

[0081] [1.2. Double-wall structure region]

[0082] The "double-wall structure region" refers to the following region:

[0083] (a) Two surfaces are opposed to each other along the sound propagation direction;

[0084] (b) Having a first skin layer on one surface side;

[0085] (c) Having a second skin layer on the other surface side;

[0086] (d) Having a core layer between the first skin layer and the second skin layer.

[0087] The "skin layer" refers to a region with a higher density compared to the interior (core layer) (i.e., a region with a lower foaming ratio compared to the interior). Generally, when the polyurethane raw material is foamed, a skin layer is formed on the outer surface. In the case of molding a polyurethane foam, if a mold release agent is applied to the mold surface, the mold release agent suppresses the generation of bubbles on the mold surface. As a result, a stronger skin layer can be formed. The thickness of the skin layer can be controlled according to the manufacturing conditions.

[0088] The sound insulation material may contain a double-wall structure region in a part thereof, or may contain a double-wall structure in its entirety.

[0089] When either the first cortex or the second cortex is disposed on the sound source side, if sound is incident on the cortex on the sound source side, a part of the sound is reflected (sound insulation) by the cortex on the sound source side. The sound passing through the cortex on the sound source side is attenuated (sound absorption) when passing through the core layer. Further, a part of the sound passing through the core layer is reflected (sound insulation) by the cortex disposed on the opposite side of the sound source, and the remaining sound passes through the cortex. Therefore, the sound insulation material having the double-wall structure region exhibits high sound insulation (sound absorption, sound insulation).

[0090] [1.3. Density ratio]

[0091] "The density ratio of the first cortex region A" refers to the ratio of the density (ρ s1 ) of the first cortex region A to the density (ρ c ) of the core layer region A (= ρ s1 / ρ c ).

[0092] "The density ratio of the second cortex region A" refers to the ratio of the density (ρ s2 ) of the second cortex region A to the density (ρ c ) of the core layer region A (= ρ s2 / ρ c ).

[0093] "Density" refers to the value measured in accordance with JIS K7222:2005.

[0094] "The core layer region A" refers to the region defined when measuring the density, which is a region excluding the high-density region of the surface layer. Specifically, "the core layer region A" refers to the region of the center of the double-wall structure region ±t A / 2.

[0095] "The first cortex region A" refers to the region defined when measuring the density, which is a region including the high-density region of the surface layer on the first cortex side. Specifically, "the first cortex region A" refers to the region from the surface on the first cortex side to the depth t A .

[0096] "The second cortex region A" refers to the region defined when measuring the density, which is a region including the high-density region of the surface layer on the second cortex side. Specifically, "the second cortex region B" refers to the region from the surface on the second cortex side to the depth t A .

[0097] t A = 5.0 mm or t0 × 0.125 (t0 is the thickness of the double-wall structure region)

[0098] The density ratio of the first cortical region A affects the sound insulation performance of the sound insulation material. Generally, the larger the density ratio of the first cortical region A, the higher the sound insulation performance. In order to obtain high sound insulation performance, the density ratio of the first cortical region A must be 1.05 or more. The density ratio is preferably 1.08 or more, 1.10 or more, 1.15 or more, or 1.20 or more.

[0099] Similarly, the density ratio of the second cortical region A affects the sound insulation performance of the sound insulation material. Generally, the larger the density ratio of the second cortical region A, the higher the sound insulation performance. In order to obtain high sound insulation performance, the density ratio of the second cortical region A must be 1.05 or more. The density ratio is preferably 1.08 or more, 1.10 or more, 1.15 or more, or 1.20 or more.

[0100] It should be noted that the conditions for the density ratios of the first cortical region A and the second cortical region A only need to satisfy at least one of the following cases.

[0101] (A) The case where the density of each region is measured using a specimen with a thickness of 5.0 mm; or

[0102] (B) The case where the density of each region is measured using a specimen with a thickness of t0 × 0.125.

[0103] When the polyurethane foam is molded using an upper and lower split mold, generally, compared with the cortical layer formed on the upper mold side, the surface state of the cortical layer formed on the lower mold side is better. In addition, a strong foaming pressure is applied to the raw material on the upper mold side. Therefore, generally, the density of the cortical layer on the upper mold side is higher than that of the cortical layer on the lower mold side.

[0104] In contrast, if the method of the present invention is used, not only is the surface state of the cortical layer on the lower mold side good, but also the surface state of the cortical layer on the upper mold side is better than that of the conventional polyurethane foam. In addition, not only does the cortical layer on the upper mold side exhibit a high density, but also the density of the cortical layer on the lower mold side is higher than that of the conventional polyurethane foam.

[0105] [1.4. Overall (OA) density]

[0106] "Overall (OA) density" refers to the density of the entire sound insulation material.

[0107] "Density" refers to the value measured in accordance with JIS K7222:2005.

[0108] Generally, the larger the mass per unit area of the sound insulation material, the higher the sound insulation performance. However, the sound insulation material described in the present invention includes a double-wall structure region with a large density ratio. Therefore, although it is light in mass (low OA density), it still exhibits high sound insulation performance.

[0109] The OA density of the sound insulation material described in the present invention is less than 130 kg / m3 If the manufacturing conditions are optimized, the OA density becomes 120 kg / m 3 or less, 110 kg / m 3 or less, 100 kg / m 3 or less, 90 kg / m 3 or less, or 80 kg / m 3 or less.

[0110] [1.5. Thickness]

[0111] In the present invention, the thickness t0 of the double-wall structure region is not particularly limited, and the optimum thickness can be selected according to the purpose. t0 can be constant regardless of the part, or it can vary depending on the part.

[0112] However, if t0 becomes too thin, the sound insulation may sometimes decrease. Therefore, t0 is preferably 10 mm or more. t0 is more preferably 20 mm or more or 30 mm or more.

[0113] [1.6. Characteristics]

[0114] [1.6.1. Average transmission loss]

[0115] "Average transmission loss" means the average value of the sound transmission loss when the frequency is from 400 Hz to 4 kHz.

[0116] "Sound transmission loss" means the value measured according to JIS A1441-1:2007.

[0117] The sound insulation material according to the present invention includes a double-wall structure region with a large density ratio. Therefore, although it is light in weight, it still shows high sound insulation. If the manufacturing conditions are optimized, the average transmission loss becomes 15.0 dB or more. If the manufacturing conditions are further optimized, the average transmission loss becomes 16.0 dB or more, 17.0 dB or more, or 18.0 dB or more.

[0118] [1.6.2. Air permeability]

[0119] "Skin layer region B" refers to the region defined when measuring the air permeability, which is a region including the high-density region of the surface layer. Specifically, "skin 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.

[0120] "Core layer region B" refers to the region defined when measuring the air permeability, which is a region that 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.

[0121] "Air permeability" means the value measured according to JIS K6400-7:2012 Method A.

[0122] 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, the difference in air permeability between the skin layer region B and the core layer region B is preferably large. In order to increase the difference in air permeability, t0 is preferably 10 mm or more.

[0123] The air permeability Q of the skin layer region B s mainly affects the sound insulation of the sound insulation material. Generally speaking, the smaller Q s is, the higher the sound insulation can be obtained. In order to obtain high sound insulation, Q s is preferably 12.0 L / min or less. Q s More preferably, it is 10.0 L / min or less, 8.0 L / min or less, or 6.0 L / min or less.

[0124] The air permeability Q of the core layer region B c mainly affects the sound absorption of the sound insulation material. Generally speaking, the higher Q c is, the higher the sound absorption can be obtained. In order to obtain high sound absorption, Q c is preferably 15.0 L / min or more. Q c More preferably, it 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.

[0125] It should be noted that the condition of the air permeability of the skin layer region B can satisfy either the first skin layer side or the second skin layer side, or both. If the method described below is used, a sound insulation material can be obtained in which the air permeability of the skin layer region B taken at least from the lower mold side satisfies the above conditions.

[0126] [1.6.3. Coefficient of kinetic friction]

[0127] The "coefficient of kinetic friction" refers to the value measured according to JIS K7125.

[0128] The sound insulation material described in the present invention is sometimes installed in a way that it is squeezed into a narrow gap. Therefore, if the coefficient of kinetic friction of the surface of the sound insulation material becomes too large, it may be difficult to insert the sound insulation material into the gap. In order to easily insert the sound insulation material, the smaller the coefficient of kinetic friction of the surface, the better.

[0129] The coefficient of kinetic friction can be mainly controlled according to the types of raw materials for manufacturing polyurethane foam (especially low molecular weight polyols and low molecular amine compounds added as needed), and the types of mold release agents used in the molding process.

[0130] In order to facilitate the insertion of the sound insulation material, the dynamic friction coefficient of the surface of the sound insulation material is preferably 0.9 or less. The dynamic friction coefficient is more preferably 0.7 or less or 0.5 or less.

[0131] It should be noted that regarding the condition of the dynamic friction coefficient, either the surface of the first skin layer or the surface of the second skin layer may satisfy this condition, or both may satisfy this condition. In order to facilitate the insertion of the sound insulation material into the gap, it is preferable that both the surface of the first skin layer and the surface of the second skin layer satisfy the condition of the dynamic friction coefficient.

[0132] [2. Manufacturing method of sound insulation material]

[0133] The manufacturing method of the sound insulation material according to the present invention includes:

[0134] The first step, which includes a raw material mixture for manufacturing polyurethane foam containing a polyol component, a polyisocyanate component, a catalyst, a foaming agent, and low molecular weight polyols;

[0135] The second step, which coats a mold release agent on the inner surface of the mold; and

[0136] The third step, which injects the aforementioned raw material mixture into the mold coated with the aforementioned mold release agent, foams and cures the aforementioned raw material mixture in the aforementioned mold to obtain the sound insulation material according to the present invention.

[0137] [2.1. First step]

[0138] First, prepare a raw material mixture for manufacturing polyurethane foam containing a polyol component, a polyisocyanate component, a catalyst, a foaming agent, and low molecular weight polyols (the first step).

[0139] The raw material mixture may further contain a low molecular amine compound.

[0140] The sound insulation material according to the present invention is preferably a polyurethane foam having a three-dimensional crosslinked structure. As a method for obtaining such a polyurethane foam, there are methods such as the following:

[0141] (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;

[0142] (b) A method of reacting a raw material mixture in which both the polyol and the polyisocyanate have 2 functional groups and the polyisocyanate is in excess, and forming biuret and / or urethane in the polymer chain.

[0143] [2.1.1. Polyol component]

[0144] "Polyol component" means one of the main raw materials for forming the polyurethane main chain, which is a mixture containing one polyol or two or more polyols.

[0145] "Polyol" refers to a compound having two or more hydroxyl groups in one molecule. Polyols (main polyols) used for forming the polyurethane main chain usually use polyols having a molecular weight of 500 or more. The type of polyol is not particularly limited as long as it can produce a polyurethane foam satisfying the above conditions.

[0146] As the main polyol, there are, for example, the following polyols:

[0147] (a) A polyol obtained by using a polyol as an initiator and adding and polymerizing ethylene oxide and propylene oxide thereto (so-called "polyether polyol");

[0148] (b) A polyol obtained by subjecting a dibasic acid (e.g., dicarboxylic acid) and a polyol to dehydration condensation (so-called "polyester polyol");

[0149] (c) A polyol in which polymer fine particles are dispersed, obtained by polymerizing a vinyl monomer (e.g., acrylonitrile, styrene) in a polyether polyol (so-called "polymer polyol").

[0150] In the present invention, any one of them can be used, or two or more can be used.

[0151] In particular, the polyol component preferably contains one or two or more polyols having a functional group number of 2 or more and 4 or less and a weight average molecular weight of 1000 or more and 10000 or less.

[0152] It should be noted that the polyol component may contain a polyol having a molecular weight of less than 1000 (e.g., a polyol having a molecular weight of about 600) as long as the weight average molecular weight is within a specified range.

[0153] If the weight average molecular weight of the polyol is too small, the polyurethane foam may sometimes become excessively hard. Therefore, the weight average molecular weight of the polyol is preferably 1000 or more. The weight average molecular weight is more preferably 1500 or more or 2000 or more.

[0154] On the other hand, if the weight average molecular weight becomes too large, the viscosity of the raw material mixture rises excessively. As a result, a high pump capacity is required in the manufacturing process. In addition, the miscibility and fluidity of the raw material mixture sometimes deteriorate. Therefore, the weight average molecular weight of the polyol is preferably 10000 or less. The weight average molecular weight is more preferably 9000 or less or 8000 or less.

[0155] [2.1.2. Polyisocyanate component]

[0156] "Polyisocyanate component" refers to another main raw material used to form the polyurethane main chain, which is one polyisocyanate or a mixture of two or more polyisocyanates.

[0157] "Polyisocyanate" refers to a compound having two or more isocyanate groups in one molecule. The types of polyisocyanates are not particularly limited as long as they can produce polyurethane foams that meet the above conditions.

[0158] Examples of polyisocyanates include the following substances:

[0159] (a) Aromatic isocyanate compounds, aliphatic isocyanate compounds, or alicyclic isocyanate compounds;

[0160] (b) Modified products of the above compounds.

[0161] Examples of aromatic isocyanate compounds include, for example:

[0162] Diphenylmethane diisocyanate (MDI),

[0163] Crude diphenylmethane diisocyanate, toluene diisocyanate (TDI),

[0164] Naphthalene diisocyanate (NDI),

[0165] p-Phenylene diisocyanate (PPDI), xylene diisocyanate (XDI),

[0166] Tetramethylxylene diisocyanate (TMXDI),

[0167] Dimethylbiphenyl diisocyanate (TODI), etc.

[0168] Examples of aliphatic isocyanate compounds include, for example:

[0169] Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), lysine triisocyanate (LTI), etc.

[0170] Examples of alicyclic isocyanate compounds include, for example:

[0171] Isophorone diisocyanate (IPDI),

[0172] Cyclohexyl diisocyanate (CHDI),

[0173] Hydrogenated XDI (H6XDI),

[0174] Hydrogenated MDI (H 12 MDI), etc.

[0175] Examples of the modified isocyanate compound include, for example, a urethane-modified product of an isocyanate compound, a dimer, a trimer, a carbodiimide-modified product, a urethane-modified product, a biuret-modified product, a urea-modified product, an isocyanurate-modified product, an oxazolidone-modified product, an isocyanate group-terminated prepolymer, and the like.

[0176] [2.1.3. Catalyst]

[0177] The "catalyst" refers to a catalyst that promotes the resinification reaction, a catalyst that promotes the foaming reaction, or a catalyst that promotes both the resinification reaction and the foaming reaction.

[0178] It should be noted that when a chemical foaming agent (water) is not used as the foaming agent, a catalyst that only promotes the foaming reaction does not need to be added.

[0179] Examples of the catalyst include an amine-based catalyst, a metal catalyst, etc. The amine-based catalyst is a catalyst that promotes both the resinification reaction and the foaming reaction. The metal catalyst is a catalyst that promotes the resinification reaction. The raw material mixture may contain any one of these catalysts, or may contain two or more.

[0180] Examples of the amine-based catalyst include:

[0181] N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine,

[0182] N,N-dimethylaminoethanol,

[0183] N,N’,N’-trimethylaminoethylpiperazine,

[0184] triethylenediamine, etc.

[0185] Examples of the metal catalyst include:

[0186] (a) Tin catalysts such as stannous octoate and dibutyltin dilaurate;

[0187] (b) Mercury catalysts such as phenylmercury propionate;

[0188] (c) Lead catalysts such as lead octenoate, etc.

[0189] [2.1.4. Foaming agent]

[0190] The "foaming agent" refers to an additive used to generate bubbles in polyurethane.

[0191] In the present invention, the foaming agent may be any one of the following foaming agents:

[0192] (a) A physical foaming agent that generates gas by reducing pressure or heating; or

[0193] (b) Chemical blowing agents that generate gas through thermal decomposition or chemical reactions.

[0194] Examples of physical blowing agents include the following blowing agents:

[0195] (a) Hydrocarbons such as cyclopentane, isopentane, and n-pentane;

[0196] (b) Halogenated compounds such as dichloromethane, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, pentafluoroethyl methyl ether, and pentafluoroisopropyl methyl ether.

[0197] Examples of chemical blowing agents include the following blowing agents:

[0198] (a) Water that reacts with isocyanate groups to generate CO2;

[0199] (b) Azodicarbonamide that generates nitrogen, carbon monoxide, carbon dioxide, or ammonia through thermal decomposition.

[0200] The raw material mixture may contain any one of these blowing agents, or may contain two or more of them.

[0201] Among these, the blowing agent is preferably water. If water is used as the blowing agent, the CO2 gas generated by the reaction of water with isocyanate groups promotes foaming. In addition, urethane bonds and urea bonds are formed by the reaction of water with isocyanate groups, promoting resinification.

[0202] [2.1.5. Low molecular weight polyols]

[0203] "Low molecular weight polyols" refers to polyols different from the polyol component, with a molecular weight less than 500.

[0204] The number of functional groups of low molecular weight polyols is preferably 2 or more and 6 or less. The number of functional groups is preferably 2 or more and 4 or less, more preferably 2 or more and 3 or less.

[0205] The molecular weight of low molecular weight polyols is preferably 300 or less. The molecular weight is preferably 200 or less, more preferably 150 or less.

[0206] The hydroxyl value of low molecular weight polyols is preferably 400 mgKOH / g or more. The hydroxyl value is preferably 600 mgKOH / g or more, 800 mgKOH / g or more, or 1000 mgKOH / g or more.

[0207] Examples of low molecular weight polyols include the following substances:

[0208] (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;

[0209] (b) Trimethylolpropane, glycerin, sorbitol, tetrapropyl ethylene diamine (quadrol).

[0210] The raw material mixture may contain any one of these low molecular weight polyols, or may contain two or more.

[0211] The low molecular weight polyols function as chain extenders. In addition, when the low molecular weight polyols have a branched chain in their molecular structure or when the raw material mixture contains a component having three or more functional groups, the low molecular weight polyols also function as crosslinking agents for crosslinking polymer chains.

[0212] If a relatively large amount of low molecular weight polyols is added to the raw material mixture, a polyurethane foam with a large and low density can be produced. In particular, the density of the skin layer on the lower mold side is higher than that of conventional polyurethane foams. It is considered that this is because: by adding a large amount of low molecular weight polyols to the raw material mixture, resinification reaction starts from the initial stage of the reaction, and in the vicinity of the lower mold, the growth of bubbles is inhibited by resinification.

[0213] [2.1.6. Low molecular amine compounds]

[0214] "Low molecular amine compounds" refer to:

[0215] (a) Compounds having a hydroxyl group (-OH) and an amino group (-NH2, -NHR, -NRR') in an alkane skeleton (alkanolamines); or

[0216] (b) Compounds having two or more amino groups (-NH2, -NHR, -NRR').

[0217] The number of functional groups of the low molecular amine compounds is preferably 2 or more and 6 or less. The number of functional groups is more preferably 2 or more and 4 or less, and even more preferably 2 or more and 3 or less.

[0218] In addition, the molecular weight of the low molecular amine compounds is preferably 200 or less. The molecular weight is more preferably 150 or less.

[0219] Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-(2-aminoethylamino)ethanol, 2-amino-2-hydroxymethyl-1,3-propanediol, ethylaminoethanol, aminobutanol, etc.

[0220] Examples of the compound having two or more amino groups include ethylenediamine and the like.

[0221] The raw material mixture may contain any one of these, or may contain two or more of them.

[0222] The low molecular weight amine compound functions as a chain extender or an amine catalyst. In addition, when the low molecular weight amine compound has a branched chain in its molecular structure or when the raw material mixture contains a component having three or more functional groups, the low molecular weight amine compound also functions as a crosslinking agent for crosslinking between polymer chains.

[0223] The low molecular weight amine compound is not necessarily essential. However, if a low molecular weight amine compound is further added to the raw material mixture, the resinification reaction is further promoted, and thus, it is possible to more easily produce a polyurethane foam having a large and low density.

[0224] [2.1.6. Other Components]

[0225] The raw material mixture for producing the polyurethane foam may further contain other components on the basis of containing the above components. Examples of the other components include foam stabilizers, defoaming agents, flame retardants, colorants, and the like. The raw material mixture may contain any one of these other components, or may contain two or more of them.

[0226] [A. Foam Stabilizer]

[0227] The "foam stabilizer" refers to an additive having the function of making the size and distribution of bubbles uniform.

[0228] If a foam stabilizer is added to the raw material mixture, a sound insulation material having uniform bubble size and distribution can be obtained. Examples of the foam stabilizer include silicone-based foam stabilizers, fluorine compound-based foam stabilizers, and known surfactants.

[0229] [B. Defoaming Agent]

[0230] The "defoaming agent" refers to an additive having the function of connecting independent bubbles, and is also referred to as a "cell opener".

[0231] When the raw material mixture is foamed, if there are independent bubbles in the polyurethane foam, the bubbles shrink during the cooling process, and accordingly, the sound insulation material also shrinks. In contrast, if a defoaming agent is added to the raw material mixture, the bubbles are connected, the number of independent bubbles decreases, and the shrinkage of the sound insulation material during the cooling process can be suppressed. Examples of the defoaming agent include hydrocarbon-based defoaming agents, ester-based defoaming agents, silicone-based defoaming agents, polyol-based defoaming agents, and the like.

[0232] Examples of hydrocarbon-based defoaming agents include oils such as polybutene.

[0233] Examples of ester-based defoaming agents include, for example, dimer acid diesters.

[0234] Examples of silicone-based defoaming agents include, for example, cyclopentasiloxane.

[0235] Examples of polyol-based defoaming agents include, for example, polyether polyols with an ethylene oxide (EO) content of 50% or more (preferably 60 - 100%).

[0236] [C. Flame Retardant]

[0237] "Flame retardant" refers to an additive that has the function of making the sound insulation material flame retardant.

[0238] If a flame retardant is added to the raw material mixture, the sound insulation material can be made flame retardant. Examples of flame retardants include the following:

[0239] (a) Phosphorus-based flame retardants, powder flame retardants such as ammonium polyphosphate;

[0240] (b) Liquid flame retardants such as phosphate ester-based flame retardants.

[0241] [D. Colorant]

[0242] "Colorant" refers to an additive that has the function of coloring the sound insulation material into a desired color.

[0243] If a colorant is added to the raw material mixture, the sound insulation material can be colored into a desired color. Examples of colorants include carbon black.

[0244] [2.1.7. Content of Each Component]

[0245] [A. Isocyanate Index]

[0246] "Isocyanate index" refers to the value obtained by multiplying the ratio of the equivalent of the isocyanate groups of the polyisocyanate in the raw material mixture to the equivalent of the active hydrogen groups in the raw material mixture by 100.

[0247] If the isocyanate index becomes too small, the strength of the polyurethane foam may be excessively reduced and the durability may decrease. In addition, during the cooling process after foaming, it may be difficult for gas to escape from the bubbles, and the sound insulation material may shrink. Therefore, the isocyanate index is preferably 80 or more. The isocyanate index is more preferably 85 or more or 90 or more.

[0248] On the other hand, if the isocyanate index becomes too large, the polyurethane foam may become excessively hard, and it may be difficult for the sound insulation material to deform according to the shape of the target surface. Therefore, the isocyanate index is preferably 120 or less. More preferably, the isocyanate index is 115 or less or 110 or less.

[0249] [B. Content of Catalyst]

[0250] The "content of catalyst" means the weight of the catalyst (parts per hundred parts of polyol, pphp) when the weight of the polyol component is set to 100.

[0251] Generally, the more the content of the catalyst, the faster the reaction will proceed in a short time. To obtain this effect, the content of the catalyst is preferably 0.1 pphp or more. More preferably, the content is 0.5 pphp or more or 1.0 pphp or more.

[0252] On the other hand, if the content of the catalyst becomes excessive, the polyurethane foam may become excessively hard. Therefore, the content of the catalyst is preferably 8.0 pphp or less. More preferably, the content is 6.0 pphp or less or 4.0 pphp or less.

[0253] [C. Content of Blowing Agent]

[0254] The "content of blowing agent" means the weight of the blowing agent (pphp) when the weight of the polyol component is set to 100.

[0255] The content of the blowing agent is preferably selected according to the type of the blowing agent to obtain the optimal content.

[0256] For example, when the blowing agent is water, generally, the more the content of water, the lower the OA density of the sound insulation material can be obtained. To obtain a sound insulation material with a low density, the content of water is preferably 1.0 pphp or more. More preferably, the content is 2.0 pphp or more or 3.0 pphp or more.

[0257] On the other hand, if the content of water becomes excessive, the OA density may be excessively reduced and the strength of the sound insulation material may be reduced. Therefore, the content of water is preferably 10.0 pphp or less. More preferably, the content is 8.0 pphp or less or 6.0 pphp or less.

[0258] [D. Content of Low-Molecular-Weight Polyols]

[0259] The "content of low-molecular-weight polyols" means the weight of the low-molecular-weight polyols (pphp) when the weight of the polyol component is set to 100.

[0260] Generally, the larger the content of low-molecular-weight polyols, the easier it is to form a cortical region with a higher density on the surface. To achieve this effect, the content of low-molecular-weight polyols is preferably 1.5 pphp or more. The content is more preferably 2.0 pphp or more, or 3.0 pphp or more.

[0261] On the other hand, since low-molecular-weight polyols do not have amino groups, the polyurethane foam is less likely to become overly hard compared to low-molecular amine compounds. However, if the content of low-molecular-weight polyols becomes excessive, the polyurethane foam may sometimes become overly hard. Therefore, the content of low-molecular-weight polyols is preferably 10.0 pphp or less. The content is more preferably 7.0 pphp or less.

[0262] [E. Content of low-molecular amine compound]

[0263] The "content of low-molecular amine compound" refers to the weight (pphp) of the low-molecular amine compound when the weight of the polyol component is set to 100.

[0264] In the present invention, the content of the low-molecular amine compound can be zero. Generally, the larger the content of the low-molecular amine compound, the easier it is to form a cortical region with a higher density on the surface. To achieve this effect, the content of the low-molecular amine compound is preferably more than 0 pphp. The content is more preferably 0.4 pphp or more, or 0.8 pphp or more.

[0265] On the other hand, the amino group of the low-molecular amine compound also functions as a catalyst for the carbamate esterification reaction. Therefore, if the content of the low-molecular amine compound becomes excessive, the polyurethane foam may sometimes become overly hard. If the polyurethane foam becomes too hard, it may sometimes be difficult to insert a sound insulation material into the voids. Therefore, the content of the low-molecular amine compound is preferably 2.0 pphp or less. The content is more preferably 1.6 pphp or less, or 1.2 pphp or less.

[0266] [F. Content of other components]

[0267] The content of other components is not particularly limited, and the optimal content can be selected according to the purpose.

[0268] [2.2. Second process]

[0269] Next, a mold release agent is applied to the inner surface of the mold (second process).

[0270] The shape of the mold is not particularly limited, and the optimal shape can be selected according to the purpose. Generally, a split mold that can be divided vertically can be used for the mold. In addition, heating means such as an electric heater and a heat medium circulation pipe are usually embedded in the mold so that the mold can be maintained at a specified temperature.

[0271] The type of mold release agent affects the air permeability of the skin layer region. In the present invention, a mold release agent containing a wax component having two melting peaks and a branched structure is used. This is different from the past.

[0272] The mold release agent preferably contains:

[0273] (a) A first wax component having a first melting peak of 70°C or higher and 90°C or lower and having a branched structure;

[0274] (b) A second wax component having a second melting peak of 100°C or higher and 130°C or lower and having a branched structure.

[0275] The first wax component is preferably a component having a weight average molecular weight of 600 or less.

[0276] The second wax component is preferably a component having a weight average molecular weight of 1000 or more.

[0277] In the case of molding a polyurethane foam, the mold release agent not only simply has the function of easily removing the molded product from the mold, but also has the function of suppressing the generation of bubbles near the surface of the mold. Therefore, if the mold release agent is coated on the mold surface during molding, a high-density skin layer can be formed on the surface of the molded product. However, if the type of mold release agent is inappropriate, there may be a case where open holes are formed on the surface of the skin layer, or cell unevenness occurs, or the density of the skin layer on the lower mold side becomes low.

[0278] In contrast, if a mold release agent that satisfies the above conditions is used, a skin layer with few open holes and cell unevenness can be formed on the surface. In addition, not only the density of the skin layer on the upper mold side becomes high, but also the density of the skin layer on the lower mold side becomes high.

[0279] The coating method of the mold release agent is not particularly limited, and the best method can be selected according to the purpose. As the coating method, there are brush coating, spraying, etc.

[0280] In addition, the coating amount of the mold release agent is not particularly limited, and the best amount can be selected according to the purpose. The coating amount is usually 10 mg / m 2 ~100 g / m 2 or so.

[0281] [2.3. Third process]

[0282] Next, the raw material mixture is injected into the mold coated with the mold release agent, and the raw material mixture is foamed and cured in the mold (third process). Thus, the sound insulation material of the present invention is obtained.

[0283] The raw material mixture is injected into a mold heated to a specified temperature. In this case, if the temperature of the mold is too low, it sometimes takes a long time for the thermal curing (curing) of the raw material mixture, resulting in a reduced productivity. In addition, sometimes the foaming of the raw material mixture becomes insufficient, and the mold cavity is not completely filled with the polyurethane foam. Therefore, the temperature of the mold is preferably 40 °C or higher. More preferably, the temperature of the mold is 50 °C or higher.

[0284] On the other hand, if the temperature of the mold becomes too high, sometimes the reactivity of the raw material mixture becomes too high, and the fluidity of the raw material mixture deteriorates. In addition, sometimes a part of the mold release agent melts excessively, and the surface of the molded product becomes rough. Therefore, the temperature of the mold is preferably 80 °C or lower. More preferably, the temperature of the mold is 70 °C or lower.

[0285] After a specified time has elapsed, the sound insulation material is taken out of the mold.

[0286] [3. Function]

[0287] If a mold release agent is applied to the mold, the raw material mixture for producing the polyurethane foam is injected into the mold, and the raw material mixture is foamed and cured in the mold, the mold release agent will inhibit the generation of bubbles on the mold surface. As a result, a sound insulation material including a double-wall structure region composed of a first skin layer / core layer / second skin layer can be obtained. In this case, if a low molecular weight polyol or a low molecular weight polyol and a low molecular amine compound are added to the raw material mixture, and a substance containing a wax component having two melting peaks and a branched structure is used as the mold release agent, a sound insulation material with excellent sound absorption and sound insulation properties and a low density can be manufactured at low cost.

[0288] The sound insulation material according to the present invention is lightweight compared to conventional polyurethane sound insulation materials, but still exhibits high sound insulation performance. It is considered that this is because:

[0289] (A) By adding a low molecular weight polyol or a low molecular weight polyol and a low molecular amine compound to the raw material mixture, the density ratios of the first skin layer region A and the second skin layer region A become larger, and the sound insulation effect achieved by the double wall is further improved; and

[0290] (B) By using a substance containing a wax component having two melting peaks and a branched structure as the mold release agent, the formation of open pores and non-uniform cell structure on the surface of the skin layer is inhibited, and the sound insulation effect achieved by the double wall is further improved.

[0291] Examples

[0292] (Examples 1 to 16, Comparative Examples 1 to 5)

[0293] [1. Preparation of Specimens]

[0294] [1.1. Raw Materials]

[0295] The polyol used is as follows.

[0296] (1) Polyol A: Polyether polyol, molecular weight 7000, functionality 3, EO content 14%, product name: KC-737, manufactured by Sanyo Chemical Industries, Ltd.

[0297] (2) Polyol B: Polyether polyol, molecular weight 5000, functionality 3, EO content 14%, product name: FA-703, manufactured by Sanyo Chemical Industries, Ltd.

[0298] (3) Polyol C: Polymer polyol, molecular weight 5000, functionality 3, product name: FA-728R, manufactured by Sanyo Chemical Industries, Ltd.

[0299] The catalyst used is as follows.

[0300] (1) Catalyst A: Amine catalyst, product name: DABCO BL-11, manufactured by Evonik

[0301] (2) Catalyst B: Amine catalyst, product name: DABCO 33LSI, manufactured by Evonik

[0302] (3) Catalyst C: Amine catalyst, product name: TOYOCAT D-60, manufactured by Tosoh Corporation

[0303] The crosslinking agent (alkanolamine or low molecular weight polyols) used is as follows.

[0304] (1) Crosslinking agent A: Diethanolamine, molecular weight 105, functionality 2, hydroxyl value 1603 mgKOH / g

[0305] (2) Crosslinking agent B: Ethylene glycol (EG), molecular weight 62, functionality 2, hydroxyl value 1810 mgKOH / g

[0306] (3) Crosslinking agent C: Diethylene glycol (DEG), molecular weight 106, functionality 2, hydroxyl value 1059 mgKOH / g

[0307] (4) Crosslinking agent D: 1,4-Butanediol, molecular weight 90, functionality 2, hydroxyl value 1245 mgKOH / g

[0308] The foam stabilizer, foam breaker, and blowing agent used are as follows, respectively.

[0309] (1) Foam stabilizer: Silicone foam stabilizer, product name: B8738LF2, manufactured by Evonik

[0310] (2) Foaming 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

[0311] (3) Blowing agent: Water

[0312] The following substances are used as polyisocyanates.

[0313] (1) Polyisocyanate A: Polymerized MDI, NCO%: 31.5%, product name: 600B, manufactured by BASF INOAC Polyurethanes

[0314] (2) Polyisocyanate B: Polymerized MDI, NCO%: 27.0%, product name: M249, manufactured by Sumika Covestro Urethane

[0315] (3) Polyisocyanate C: 50 / 50 mixture of TDI-80 and polymerized MDI, NCO%: 31.5%, product name: TM50, manufactured by Mitsui Chemicals

[0316] The following substances are used as mold release agents.

[0317] (1) Mold release agent A: Branched wax-based mold release agent, first melting peak at 81.0 °C, second melting peak at 110.2 °C, product name: FRX-C8, manufactured by NEOS

[0318] (2) Mold release agent B: Branched wax-based mold release agent, melting peak at 106.9 °C, product name: M975, manufactured by Chukyo Yushi

[0319] (3) Mold release agent C: Straight-chain wax-based mold release agent, first melting peak at 93.2 °C, second melting peak at 108.3 °C, product name: T-626, manufactured by Chukyo Yushi

[0320] The mixing ratios of the raw materials used are shown in Table 1. It should be noted that the OA density of each specimen and the type of mold release agent used in the molding are also shown in Table 1.

[0321] [Table 1]

[0322]

[0323] [1.2. Molding]

[0324] The following mold is used for the foaming molding:

[0325] (a) A mold divided into an upper mold and a lower mold, with the inner surface shape of the mold being a cuboid and the inner surface dimensions being 500 × 500 × t20 mm (mold internal volume: 5000 cm 3 ) and

[0326] (b) is divided into an upper mold and a lower mold. The inner surface shape of the mold is a cuboid, and the inner surface dimensions are 500×250×t40 mm (mold internal volume: 5000 cm 3 ).

[0327] A mold release agent is applied to the inner surface of the mold by spraying. The application amount is set to approximately 25 g / m 2 . A specified amount of raw material mixture is injected into the mold maintained at 60°C, and the raw material mixture is foamed and cured in the mold. After a specified time, demolding is performed to obtain a polyurethane foam.

[0328] [2. Test method]

[0329] [2.1. OA density]

[0330] For the specimen for OA density measurement, a polyurethane foam of 500×250×t40 mm is used. According to JIS K7222:2005, the OA density of the specimen is measured.

[0331] [2.2. Upper mold side surface layer density, core density, lower mold side surface layer density]

[0332] The 500×250×t40 mm polyurethane foam is cut into a cuboid of 51 mm square × t40 mm. Then, the cuboid is sliced parallel to the upper and lower surfaces of the cuboid, and slices of 51 mm square × t5 mm are obtained from the upper mold side surface layer area, the central area, and the lower mold side surface layer area of the cuboid respectively.

[0333] Using these slices, according to JIS K7222:2005, the following parameters are measured:

[0334] (A) Upper mold side surface layer density (density of the first skin layer area A) ρ s1 ,

[0335] (B) Core density (density of the core layer area A) ρ c , and

[0336] (C) Lower mold side surface layer density (density of the second skin layer area A) ρ s2 .

[0337] Furthermore, using the obtained densities, the following parameters are calculated:

[0338] (A) Upper mold side surface layer density ratio (density ratio of the first skin layer A) ρ s1 / ρ c , and

[0339] (B) Lower mold side surface layer density ratio (density ratio of the second skin layer A) ρ s2 / ρc .

[0340] [2.3. Air permeability]

[0341] Cut a 500×250×t40 polyurethane foam into a cuboid with a side length of 51 mm×t40 mm. Then, slice the cuboid parallel to its upper and lower surfaces to obtain slices with a side length of 51 mm×t10 mm from the central region and the lower mold side surface layer region of the cuboid respectively.

[0342] Using these slices, measure the following parameters according to JIS K6400-7:2012 Method A:

[0343] (A) Air permeability of the internal core layer (air permeability of the core layer region B) Q c and

[0344] (B) Air permeability of the surface skin (air permeability of the skin layer region B) Q s .

[0345] [2.4. Sound insulation performance]

[0346] Form an opening of 400 mm×400 mm in the center of a 500×500×t20 mm polyurethane foam. Use it to evaluate the sound insulation performance according to JIS A1441-1:2007. Measure the sound transmission loss using the 1 / 3 octave frequency band and find the average of the sound transmission loss at frequencies from 400 Hz to 4 kHz (average transmission loss).

[0347] [2.5. Coefficient of dynamic friction]

[0348] Cut a 500×250×t40 mm polyurethane foam into a cuboid with a side length of 63 mm×t40 mm. Then, slice the cuboid parallel to its upper and lower surfaces to obtain a slice with a side length of 63 mm×t10 mm from the lower mold side surface layer region of the cuboid. Use this slice to measure the coefficient of dynamic friction according to JIS K7125.

[0349] [3. Results]

[0350] The results are shown in Table 2. In addition, Figure 1 shows the measurement results of the sound transmission loss of the sound insulation materials obtained from Examples 1 to 3, Comparative Example 1, and Comparative Example 5. From Table 2 and Figure 1 the following conclusions can be drawn.

[0351] It should be noted that in Table 2, regarding the density ratio (ρ s1 / ρ c , ρ s2 / ρ c) "◎" indicates a density ratio of 1.10 or more, "○" indicates a density ratio of more than 1.08 and less than 1.10, "△" indicates a density ratio of more than 1.05 and less than 1.08, and "×" indicates a density ratio of less than 1.05.

[0352] Regarding the air permeability (Q s ) of the surface skin, "◎" indicates an air permeability of 4.0 L / min or less, "○" indicates an air permeability exceeding 4.0 L / min and being 8.0 L / min or less, "△" indicates an air permeability exceeding 8.0 L / min and being 12.0 L / min or less, and "×" indicates an air permeability exceeding 12.0 L / min.

[0353] Regarding the difference in air permeability between the surface layer and the inner core layer (ΔQ = Q c -Q s ), "◎" indicates a difference in air permeability of 20.0 L / min or more, "○" indicates a difference in air permeability of more than 15.0 L / min and less than 20.0 L / min, and "△" indicates a difference in air permeability of less than 15.0 L / min.

[0354] Regarding sound insulation, "◎" indicates an average transmission loss of 16.0 dB or more, "○" indicates an average transmission loss of more than 12.0 dB and less than 16.0 dB, "△" indicates an average transmission loss of more than 8.0 dB and less than 12.0 dB, and "×" indicates an average transmission loss of less than 8.0 dB.

[0355] (1) The average transmission loss of Comparative Example 1 is 14.3 dB. In addition, the density ratio ρ s2 / ρ c of the surface layer of the lower mold in Comparative Example 1 is 1.04. It is considered that this is because low molecular weight polyols are not contained in the raw material mixture.

[0356] (2) The average transmission loss of Comparative Example 2 is 10.9 dB. In addition, the air permeability Q s of the surface skin layer in Comparative Example 2 increases to 26.9 L / min. It is considered that this is because low molecular weight polyols are not contained in the raw material mixture and the mold release agent is inappropriate.

[0357] (3) The average transmission loss of Comparative Example 3 is 7.5 dB. In addition, the density ratio ρ s2 / ρ c of the surface layer on the lower mold side in Comparative Example 3 is 1.04. Furthermore, the air permeability Q s of the surface skin layer in Comparative Example 3 increases to 14.7 L / min. It is considered that this is because low molecular weight polyols are not contained in the raw material mixture and the mold release agent is inappropriate.

[0358] (4) The average transmission loss of Comparative Example 4 was 20.9 dB, showing good sound insulation. However, the OA density of Comparative Example 4 increased to 150 kg / m 3 . It is considered that this is because the raw material mixture does not contain low-molecular-weight polyols and the amount of diethanolamine is relatively excessive.

[0359] (5) The average transmission loss of Comparative Example 5 was 15.8 dB, showing good sound insulation. However, the OA density of Comparative Example 5 increased to 150 kg / m 3 . In addition, the surface density ratio ρ s2 / ρ c of the lower mold of Comparative Example 5 was 1.03. It is considered that this is because the raw material mixture does not contain low-molecular-weight polyols, the amount of diethanolamine is relatively excessive, and the release agent is inappropriate.

[0360] (6) The OA density of Examples 1 to 16 was 80 kg / m 3 or less, and the average transmission loss was 16.0 dB or more. It is considered that this is because the raw material mixture contains a relatively large amount of low-molecular-weight polyols and an appropriate release agent is used.

[0361] [Table 2]

[0362]

[0363] As described above, the embodiments of the present invention have been described in detail, but the present invention is not limited to the above embodiments at all, and various changes can be made without departing from the gist of the present invention.

[0364] Industrial Applicability

[0365] The sound insulation material described in the present invention can be used for the following materials:

[0366] (a) A sound insulation material inserted into the gaps around the fenders, instrument panels, engine hoods, dash silencers, floor silencers, etc. of automobiles;

[0367] (b) A sound insulation material covering the surroundings of noise components such as motors and compressors.

Claims

1. A sound insulation material comprising a polyurethane foam, wherein the polyurethane foam includes a double-wall structure region composed of a first skin layer / core layer / second skin layer, The density ratio of the first skin layer region A is 1.05 or more, The density ratio of the second skin layer region A is 1.05 or more, The overall (OA) density of the sound insulation material is less than 130 kg / m 3 , wherein, The "density ratio of the first cortical region A" refers to the density (ρ s1 ) of the first cortical region A relative to the density (ρ c ) of the core region A (= ρ s1 / ρ c ). The "density ratio of the second cortical region A" refers to the density (ρ s2 ) of the second cortical region A relative to the density (ρ c ) of the core layer region A (= ρ s2 / ρ c ). The "core layer region A" refers to the region within ±t A / 2 starting from the center of the double-wall structure region, The "first cortical region A" refers to the region from the surface on the first cortical side of the double-wall structure region to a depth of t A up to The "second cortical region B" refers to the region from the surface on the second cortical side of the double-wall structure region to a depth of t A up to t A = 5.0 mm or t0 × 0.125, where t0 is the thickness of the double-wall structure region.

2. The sound insulation material according to claim 1, having an average transmission loss of 15.0 dB or more, wherein, The "average transmission loss" refers to the average value of the sound transmission loss at a frequency of 400 Hz to 4 kHz, The "sound transmission loss" refers to the value measured in accordance with JIS A1441-1:2007.

3. The sound insulation material according to claim 1, wherein, The air permeability of the skin layer region B is 12.0 L / min or less, wherein, The "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 "air permeability" refers to the value measured in accordance with JIS K6400-7:2012 Method A.

4. A method for manufacturing a sound insulation material, comprising: A first step of preparing a raw material mixture for manufacturing a polyurethane foam containing a polyol component, a polyisocyanate component, a catalyst, a foaming agent, and low molecular weight polyols; A second step of coating a mold release agent on the inner surface of the mold; and A third step of injecting the raw material mixture into the mold coated with the mold release agent, foaming and curing the raw material mixture in the mold to obtain the sound insulation material according to claim 1, The mold release agent contains a wax component having two melting peaks and a branched structure, Among them, The "low molecular weight polyols" refers to polyols different from the polyol component, having a molecular weight of less than 500.

5. The manufacturing method of the sound insulation material according to claim 4, wherein, The raw material mixture further contains a low molecular amine compound.

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