Polyol composition for raw materials of flexible polyurethane foam for sound-insulating and sound-absorbing materials

Abstract

To provide a polyurethane foam with excellent low-frequency sound insulation performance. [Solution] A polyol composition for a flexible polyurethane foam raw material for sound-insulating and absorbing materials, comprising a polyol component (A), silica particles (B), a blowing agent (C), and a catalyst (D), wherein (A) contains the following polyether polyol (a), and the average particle size of (B) by volume is 0.1 to 100 μm; a polyurethane foam obtained by reacting a polyol component containing the above-described polyol composition with a polyisocyanate component is used.

Description

Technical Field

[0001] The present invention relates to a polyol composition for a raw material of a soft polyurethane foam for a sound insulation and absorption material.

Background Art

[0002] Conventionally, various polyurethane foams have been used as sound insulation and absorption materials for vehicles (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, for the purpose of improving fuel efficiency in vehicle applications such as automobiles, the weight reduction of each component to be mounted has been progressing. Along with this, in polyurethane foam products used as interior materials (especially sound insulation and absorption materials), the sound insulation and absorption performance inside the vehicle during weight reduction has come to be required to have performance better than before. However, the polyurethane foam of the prior art has had a problem that it does not have a satisfactory level of sound insulation and absorption performance.

Means for Solving the Problems

[0005] As a result of intensive studies, the present inventors have reached the present invention. In other words, the present invention relates to a polyol composition for a flexible polyurethane foam raw material for sound-insulating and absorbing materials, comprising a polyol component (A), silica particles (B), a blowing agent (C), and a catalyst (D), wherein (A) contains the following polyether polyol (a), and the average particle size of (B) by volume is 0.1 to 100 μm; a polyurethane foam obtained by reacting a polyol component containing the above-described polyol composition with a polyisocyanate component; and a sound-insulating and absorbing material for vehicles made of the above-described polyurethane foam. Polyether polyol (a): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 2.5 to 8.0, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by weight. [Effects of the Invention]

[0006] The polyurethane foam obtained by reacting the polyol composition of the present invention exhibits excellent low-frequency sound insulation performance. [Modes for carrying out the invention]

[0007] The polyol composition for the raw material of flexible polyurethane foam for sound-insulating and sound-absorbing materials of the present invention contains a polyol component (A), silica particles (B), a blowing agent (C), and a catalyst (D), wherein (A) contains the following polyether polyol (a), and the average particle size of (B) by volume is 0.1 to 100 μm. Polyether polyol (a): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 2.5 to 8.0, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by weight.

[0008] The polyol component (A) is a compound having at least two (preferably two to eight) hydroxyl groups. Examples include compounds having a structure in which an alkylene oxide (hereinafter abbreviated as AO) with 2 to 8 or more carbon atoms is added to a compound having at least two active hydrogen atoms, such as a polyhydric alcohol, polyhydric phenol, amine, or polycarboxylic acid.

[0009] Polyhydric alcohols include dihydric alcohols with 2 to 20 carbon atoms (aliphatic diols, e.g., alkylene glycols such as ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; alicyclic diols, e.g., cycloalkylene glycols such as cyclohexanediol and cyclohexanedimethanol), trihydric alcohols with 3 to 20 carbon atoms (aliphatic triols, e.g., alkanetriols such as glycerin, trimethylolpropane, trimethylolethane, and hexanetriol), and tetrahydric polyhydric alcohols with 5 to 24 carbon atoms. Examples include aliphatic polyols, such as pentaerythritol (4), sorbitol (6), mannitol (6), sorbitan (4), polyglycerin (degree of polymerization: 2-8) (4-10), polypentaerythritol (degree of polymerization: 2-4) (6-8), and other alkane polyols; intramolecular or intermolecular dehydrated products of alkanetriols; sugars such as sucrose (8), maltose (8), glucose (5), mannose (5), fructose (5), methyl glucoside (4), and their derivatives), and two or more of these may be used in combination.

[0010] Examples of polyhydric phenols include monocyclic polyhydric phenols such as pyrogallol, hydroquinone, and phloroglucin; bisphenols such as bisphenol A, bisphenol F, and bisphenol sulfone; condensates of phenol and formaldehyde (novolac); and polyphenols as described in U.S. Patent No. 3,265,641, and two or more of these may be used in combination.

[0011] Examples of amines include those with 2 to 10 or more active hydrogen atoms, such as ammonia and aliphatic amines. Examples of aliphatic amines include alkanolamines with 2 to 20 carbon atoms (e.g., monoethanolamine, diethanolamine, and isopropanolamine), alkylamines with 1 to 20 carbon atoms (e.g., n-butylamine and octylamine), alkylenediamines with 2 to 6 carbon atoms (e.g., ethylenediamine, propylenediamine, and hexamethylenediamine), and polyalkylene polyamines with 4 to 20 carbon atoms (dialkylentriamines to hexaalkyleneheptamines with 2 to 6 carbon atoms in the alkylene group, e.g., diethylenetriamine and triethylenetetramine). Other examples include aromatic mono- or polyamines having 6 to 20 carbon atoms (e.g., aniline, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline, and diphenyl etherdiamine), alicyclic amines having 4 to 20 carbon atoms (isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine), and heterocyclic amines having 4 to 20 carbon atoms (e.g., piperazine, aminoethylpiperazine, and those described in Japanese Patent Publication No. 55-21044). Two or more of these amines may be used in combination.

[0012] Examples of polycarboxylic acids include aliphatic polycarboxylic acids with 4 to 18 carbon atoms (such as succinic acid, adipic acid, sebacic acid, glutaric acid, and azelaic acid), and aromatic polycarboxylic acids with 8 to 18 carbon atoms (such as phthalic acid, terephthalic acid, isophthalic acid, and trimellitic acid). Two or more of these may be used in combination.

[0013] Two or more of these active hydrogen-containing compounds may be used in combination. Among these, polyhydric alcohols are preferred.

[0014] Examples of AOs with 2 to 8 or more carbon atoms that can be added to the above-mentioned active hydrogen-containing compound include ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3-, 1,4- and 2,3-butylene oxide, styrene oxide, and combinations of two or more of these (block and / or random addition). Among these, PO and / or EO are preferred.

[0015] The polyol component (A) contains the following polyether polyol (a).

[0016] Polyether polyol (a): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 2.5 to 8.0, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by mass.

[0017] Furthermore, from the viewpoint of moldability, it is preferable that the polyether polyol (a) includes the following polyether polyols (a1) and (a2).

[0018] Polyether polyol (a1): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 2.5 to 3.5, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by weight. Polyether polyol (a2): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 3.5 to 8.0, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by weight.

[0019] Polyoxyethylene polyoxypropylene polyol is a polyol having polyoxyalkylene groups, each consisting of two or more EO and PO groups.

[0020] (a1) is an AO adduct consisting of EO and PO of the above-mentioned active hydrogen-containing compound, and two or more AO adducts may be used in combination. The active hydrogen-containing compound which is the raw material of (a1) may be used in combination of two or more kinds, and polyhydric alcohols having 2 to 4 valences are preferable, and polyhydric alcohols having 3 valences are more preferable. As the method for adding EO and PO to the active hydrogen-containing compound, either block addition or random addition may be used, but block addition (particularly in the order of PO-EO (chipped)) is preferable.

[0021] The average number of functional groups per molecule of (a1) is 2.5 to 3.5. The lower limit is preferably 2.8, and the upper limit is preferably 3.2. Even if those having a number of functional groups outside this range are included, as long as they are AO adducts of two or more kinds of active hydrogen-containing compounds and their average number of functional groups is 2.5 to 3.5 (the same applies to the following average number of functional groups). Here, the average number of functional groups is a theoretical value calculated from the average number of functional groups of the raw material, regarded as the number of functional groups. However, as the number of functional groups of (a1), 2 to 4 are preferable, and more preferably 3. The hydroxyl value is 20 to 150 (mgKOH / g, the same applies to the following hydroxyl values). The lower limit is preferably 22, more preferably 24, the upper limit is preferably 60, more preferably 50. The content of the oxyethylene unit at the terminal of (a1) (hereinafter abbreviated as terminal EO unit, the same applies to (a2) below) is 10 to 30% by weight (hereinafter, weight% may be simply denoted as %). % other than the sound absorption rate means weight%. The lower limit is preferably 12%, more preferably 14%, the upper limit is preferably 25%, more preferably 20%. In addition, the content of the oxyethylene unit other than the terminal EO unit of (a1) (hereinafter abbreviated as internal EO unit, the same applies to (a2) below) is preferably 5% or less, more preferably 0%. When the average number of functional groups of (a1) is 2.5 to 3.5, curability can be ensured. Also, when the hydroxyl value is 20 to 150 and the content of the terminal EO unit is 10 to 30%, the cream time at the initial stage of foaming becomes long and the liquid flowability can be ensured, so that a foam with good moldability and less likely to cause molding defects can be obtained.

[0022] Examples of the polyether polyol (a2) include AO adducts of the above active hydrogen-containing compounds, and two or more kinds of AO adducts may be used in combination. The active hydrogen-containing compounds that are the raw materials for (a2) may be used in combination of two or more kinds, polyhydric alcohols having 6 to 10 hydroxyl groups are preferred, and polyhydric alcohols having 8 hydroxyl groups are more preferred. The above AO consists of EO and PO. As the addition method of EO and PO, either block addition or random addition may be used, but block addition (especially in the order of PO-EO (chipped)) is preferred.

[0023] The average number of functional groups per molecule of (a2) is 3.5 to 8.0. The lower limit is preferably 3.6, more preferably 3.7, the upper limit is preferably 7.5, more preferably 7.0. As the number of functional groups of (a2), 3.7 to 7.0 (especially 4.15) is preferred. The hydroxyl value is 20 to 150. The lower limit is preferably 20, more preferably 30, the upper limit is preferably 60, more preferably 40. The content of terminal EO units is 10 to 30%. The lower limit is preferably 12%, more preferably 14%, the upper limit is preferably 25%, more preferably 20%. In addition, the content of internal EO units is preferably 5% or less, more preferably 0%. When the average number of functional groups of (a2) is 3.5 to 8.0, curability can be ensured. Also, when the hydroxyl value is 20 to 150 and the content of terminal EO units is 10 to 30%, the cream time at the initial stage of foaming becomes longer and the liquid flowability can be ensured, so that a foam with good moldability and less likely to cause molding defects can be obtained.

[0024] In the present invention, in the polyol component (A), in addition to the polyether polyol (a) which is an essential component, other polyols (compounds other than (a) obtained by adding AO to the above compound having at least 2 active hydrogens, and polyester polyols, etc.), the above compound having at least 2 active hydrogens, and a monool may be contained.

[0025] The polyester polyols include the aforementioned polyhydric alcohols and / or polyether polyols [for example, dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol; mixtures of these dihydric alcohols with trihydric or higher polyhydric alcohols such as glycerin and trimethylolpropane; and low molar (1-10 molar) AO adducts of these polyhydric alcohols] and the aforementioned polycarboxylic acids or their ester-forming derivatives [anhydrous, lower alkyl (carbon of alkyl group)]. Examples include: 1-4) Condensation reaction products with esters, etc. (e.g., adipic acid, sebacic acid, maleic anhydride, phthalic anhydride, dimethyl terephthalate); condensation reaction products of the above-mentioned polyhydric alcohols and / or polyether polyols with the carboxylic acid anhydrides and AO; alkyleon oxide (EO, PO, etc.) adducts of these condensation reaction products; polylactone polyols, for example, those obtained by ring-opening polymerization of lactones (ε-caprolactone, etc.) using the above-mentioned polyhydric alcohol as an initiator; polycarbonate polyols, for example, reaction products of the above-mentioned polyhydric alcohols and alkylene carbonates; and so on.

[0026] Examples of polyols include polymer polyols (such as polyesters) other than those used in polyether polyols; polydiene polyols such as polybutadiene polyols and their hydrogenated products; acrylic polyols, hydroxyl group-containing vinyl polymers described in Japanese Patent Publication No. 58-57413 and Japanese Patent Publication No. 58-57414, etc.; natural oil-based polyols such as castor oil; modified products of natural oil-based polyols such as castor oil modified products (e.g., polyhydric alcohol transesterification products, hydrogenated products); terminal radical polymerizable functional group-containing active hydrogen compounds (including monools) described in International Publication No. WO98 / 44016; modified polyols obtained by jumping (a) with alkylene halides such as methylenedihalides; OH-terminated prepolymers of (a); and the like. Among compounds having two active hydrogens, alkanolamines are preferred as amines.

[0027] When polyether polyol (a) contains polyether polyols (a1) and (a2), the content of polyether polyol (a1) based on the total weight of polyol component (A) is preferably 50 to 90% by weight. The lower limit is more preferably 55% by weight, particularly preferably 60% by weight, and the upper limit is more preferably 80% by weight, particularly preferably 75% by weight. The content of polyether polyol (a2) based on the total weight of polyol component (A) is preferably 10 to 50% by weight. The lower limit is more preferably 20% by weight, particularly preferably 25% by weight, and the upper limit is more preferably 45% by weight, particularly preferably 40% by weight. If (a1) is 50% by weight or (a2) is 50% by weight or less, the cells of the urethane foam will not be closed cells and the moldability will be good. If (a1) is 90% by weight or less or (a2) is 10% by weight or more, the curability will be good and productivity will be improved. The total content of (a1), (a2) and polymer polyols composed of them in polyol component (A) is preferably 80% by weight or more, more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 99% by weight or more. The content of other polyols or active hydrogen components other than (a1) and (a2) is preferably 20% by weight or less, more preferably 10% by weight or less, particularly preferably 5% by weight or less, and most preferably 1% by weight or less.

[0028] In this invention, silica particles (B) are particles that mainly contain SiO2. From the viewpoint of low-frequency sound insulation properties of urethane foam, silica particles (B) obtained from calcined rice husks are preferred. Calcined rice husks can be obtained, for example, by burning rice husks at high temperatures to remove organic matter and moisture, concentrating the silica component in the rice husks to 70% by weight, dissolving the silica component from the burnt rice husk ash, separating it, and drying it. This can be obtained from the market as white silica, etc. The silica particle (B) content based on the total weight of the polyol composition is preferably 5 to 20% by weight, and more preferably 7 to 15% by weight.

[0029] The volume-based average particle diameter of silica particles (B) is 0.1 to 100 μm, preferably 0.1 to 20 μm, and more preferably 1 to 10 μm, from the viewpoint of low-frequency sound insulation and dispersibility. The volume-average particle diameter of silica particles (B) was measured using dynamic light scattering under the conditions of 15 minutes of sonication in a methanol dispersion with a silica concentration of 5 wt% at room temperature (25°C).

[0030] Water is preferred as the blowing agent (C). When water is used alone for (C), the water content is preferably 0.2 to 20% by weight, and more preferably 2 to 7% by weight, based on 100 parts by weight of polyol component (A). When used in combination with other blowing agents, the water content is preferably 0.1 to 10% by weight. Other materials, such as hydrogen atom-containing halogenated hydrocarbons, low-boiling-point hydrocarbons, and liquefied carbon dioxide, may be used as needed.

[0031] Specific examples of hydrogen atom-containing halogenated hydrocarbons include HCFC (hydrochlorofluorocarbon) types (e.g., HCFC-123, HCFC-141b, HCFC-22, and HCFC-142b); and HFC (hydrofluorocarbon) types (e.g., HFC-134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, and HFC-365mfc). Of these, preferred are HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc, and mixtures of two or more of these. When using hydrogen atom-containing halogenated hydrocarbons, the content is preferably 50% by weight or less, and more preferably 5 to 45% by weight, based on (A) 100 parts by weight.

[0032] Low-boiling point hydrocarbons are hydrocarbons with a boiling point typically ranging from -5 to 70°C. Specific examples include butane, pentane, cyclopentane, and mixtures thereof. When using low-boiling hydrocarbons, the content is preferably 40% by weight or less, and more preferably 5 to 30% by weight, based on 100 parts by weight of (A). When using liquefied carbon dioxide, the content is preferably 30% by weight or less, and more preferably 25% by weight or less, based on 100 parts by weight of (A).

[0033] As catalyst (D), any conventional catalyst that promotes the urethane reaction can be used, including tertiary amines having a hydroxyl group, such as N,N-dimethylethanolamine, N,N-dimethylhexanolamine, and N,N-dimethylaminopropyldipropanolamine; tertiary amines without a hydroxyl group and their carboxylate salts, such as triethylenediamine, bis(N,N-dimethylamino-2-ethyl) ether, and N,N,N',N'-tetramethylhexamethylenediamine; and organometallic compounds such as carboxylate metal salts, such as potassium acetate, potassium octoate, stanus octoate, and dibutyltin dilaurate; and two or more of these may be used in combination. Among these (D), preferred are tertiary amines having at least a portion of hydroxyl groups, more preferably tertiary amines having hydroxyl groups alone, and combinations of tertiary amines having hydroxyl groups and tertiary amines not having hydroxyl groups (especially triethylenediamine). When tertiary amines having hydroxyl groups and, if necessary, tertiary amines not having hydroxyl groups are used as (D), the content of tertiary amines having hydroxyl groups in the tertiary amine is preferably 20 to 100% by weight. The lower limit is more preferably 30% by weight, particularly preferably 40% by weight, and most preferably 50% by weight, and the upper limit is more preferably 90% by weight, particularly preferably 80% by weight, and most preferably 70% by weight. The content of (D) is preferably 0.01 to 6% by weight, and more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of polyol component (A).

[0034] In the present invention, other additives (E), such as a foam stabilizer (E1), may be included as needed. As the foam stabilizer (E1), all foam stabilizers commonly used in the manufacture of polyurethane foam can be used. Examples include dimethylsiloxane-based foam stabilizers [e.g., "SRX-253" from Tore Dow Corning Silicone Co., Ltd.], polyether-modified dimethylsiloxane-based foam stabilizers [e.g., "L-5309" and "SZ-1311" from Nippon Unicar Co., Ltd., and "SF-2972" and "SRX-274C" from Tore Dow Corning Silicone Co., Ltd.], and other silicone foam stabilizers. The content of (E1) is preferably 5% by weight or less, and more preferably 0.2 to 3% by weight, based on 100 parts by weight of polyol component (A).

[0035] Furthermore, it may contain crosslinking agents (E2) (such as triethanolamine), colorants (dyes, pigments), flame retardants (such as phosphate esters, halogenated phosphate esters), anti-aging agents (such as triazole-based and benzophenone-based agents), antioxidants (such as hindered phenol-based and hindered amine-based agents). Based on 100 parts by weight of polyol component (A), the content of these additives is preferably 1% by weight or less for the crosslinking agent (E2). Preferably 1% by weight or less for the colorant. Preferably 5% by weight or less for the flame retardant, more preferably 2% by weight or less. Preferably 1% by weight or less for the anti-aging agent, more preferably 0.5% by weight or less. Preferably 1% by weight or less for the antioxidant, more preferably 0.01 to 0.5% by weight.

[0036] The present invention is a polyurethane foam obtained by reacting a polyol component, which includes any of the polyol compositions described above, with a polyisocyanate component.

[0037] The polyisocyanate component used in the present invention can be one that is commonly used in polyurethane foams. Examples of such isocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, modified products thereof (e.g., modified products containing carbodiimide groups, allophanate groups, urethane groups, urea groups, biuret groups, isocynurate groups, or oxazolidone groups), and mixtures of two or more of these.

[0038] Aromatic polyisocyanates include aromatic diisocyanates with 6 to 16 carbon atoms (excluding carbon atoms in the NCO group; the same applies to the following isocyanates), aromatic triisocyanates with 6 to 20 carbon atoms, and crude products of these isocyanates. Specific examples include 1,3- and 1,4-phenylenediisocyanate, 2,4- and 2,6-tolylenediisocyanate (TDI), crude TDI, 2,4'- and 4,4'-diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (crude MDI), naphthylene-1,5-diisocyanate, and triphenylmethane-4,4',4''-triisocyanate.

[0039] Examples of aliphatic polyisocyanates include aliphatic diisocyanates with 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0040] Examples of alicyclic polyisocyanates include alicyclic diisocyanates with 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate.

[0041] Examples of aromatic aliphatic polyisocyanates include aromatic aliphatic diisocyanates with 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate.

[0042] Specific examples of modified polyisocyanates include urethane-modified MDI, carbodiimide-modified MDI, sucrose-modified TDI, and castor oil-modified MDI.

[0043] Of these, preferred are aromatic polyisocyanates and their modified products, more preferably one or more selected from MDI, crude MDI, TDI, crude TDI, and urethane group-containing modified products thereof, and particularly preferred is a combination of MDI and TDI.

[0044] The isocyanate index [(equivalent ratio of NCO group / active hydrogen atom-containing group) × 100] used in the production of the polyurethane foam of the present invention is preferably 60 to 100, more preferably 65 to 95, and particularly preferably 70 to 90. When the isocyanate index is 60 or higher, the liquid flowability is good and the moldability is good, and when it is 100 or lower, the curing properties are good and productivity is improved.

[0045] An example of the method for producing the polyurethane foam of the present invention is as follows: First, predetermined amounts of polyol component (A), silica particles (B), blowing agent (C), catalyst (D), and other additives (E) such as foam stabilizer (E1) are mixed. Next, this mixture and the polyisocyanate component (preferably with a liquid temperature of 20-40°C) are rapidly mixed using a polyurethane low-pressure or high-pressure injection foamer or stirrer. The resulting mixture (foaming stock) is injected into a closed or open mold (made of metal or resin, preferably 15-65°C), and the urethane reaction is carried out. After curing for a predetermined time (e.g., 0.5-6 minutes), the mold is removed to obtain the polyurethane foam. When using a closed mold, a pack ratio of 1.0-2.0 times is preferred. Polyurethane foam can also be obtained by spray foaming or continuous foaming.

[0046] Because the polyurethane foam of the present invention has excellent sound insulation and absorption performance, it can be suitably used as a sound insulation and absorption material for vehicles.

[0047] The sound-absorbing and insulating material for vehicles of the present invention is considerably more than the polyurethane foam described above, and is particularly suitable for use as a sound-absorbing and insulating material for automobiles (for example, between the engine compartment and the seats). [Examples]

[0048] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % refers to weight percent and parts refers to parts by weight.

[0049] The raw materials for the polyurethane foam in the examples and comparative examples are as follows: Polyether polyol a1-1: PO·EO block adduct of glycerin (hydroxyl value 28, content of terminal EO units = 15%). Polyether polyol a1-2: PO·EO block adduct of glycerin (hydroxyl value 24, content of terminal EO units = 72%). Polyether polyol a2-1: A mixture of PO·EO block adducts of sorbitol and PO·EO block adducts of glycerin (hydroxyl value 32.5, content of terminal EO units = 15%). Silica particles B-1: Calcined rice husk product (manufactured by MIT Corporation, RHS-C) Foaming agent C-1: Water Catalyst D-1: N,N-dimethylaminopropyldipropanolamine [Manufactured by Sunapro Co., Ltd., U-CAT2024] Catalyst D-2: Manufactured by Evonik Japan Co., Ltd., Dabco 33LV Catalyst D-3: Manufactured by Evonik Japan Co., Ltd., Dabco BL-19 Foam stabilizer E1-1: Silicone-based foam stabilizer (manufactured by Evonik Japan Co., Ltd., Tegostab B8738) Crosslinking agent E2-1: Triethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Polyisocyanate component I-1: TDI / MDI = 80 / 20 (weight ratio) (Cosmonate TM-20, manufactured by Mitsui Chemicals, Inc.)

[0050] <Examples 1-2 and Comparative Examples 1-3> Polyol components and isocyanate components containing the polyol composition shown in Table 1 were warmed to 25°C, then hand-mixed at 3000 rpm for 10 seconds. The mixture was then poured into a 300 × 300 × 100 mm mold warmed to 65°C, the mold was closed, and the mixture was allowed to react and cure for 5 minutes to form polyurethane foam. The results of the measurement of the physical properties of each foam are shown in Table 1. The physical properties of the polyurethane foam were measured according to the method of JIS K 6401. However, the sound absorption coefficient was measured in accordance with ASTM-E-1050.

[0051] [Table 1]

[0052] As is clear from Table 1, the polyurethane foams of Examples 1 and 2, manufactured using the polyol composition of the present invention, exhibited particularly high sound absorption coefficients and transmission loss rates at low frequencies, demonstrating excellent low-frequency sound insulation. On the other hand, the polyurethane foams of Comparative Examples 1 to 3, manufactured using polyol compositions that did not contain silica particles (B), exhibited particularly low sound absorption coefficients and transmission loss rates at low frequencies, resulting in poor low-frequency sound insulation.

Claims

1. A polyol composition for use as a raw material for flexible polyurethane foam for sound-insulating and absorbing materials, comprising a polyol component (A), silica particles (B), a blowing agent (C), and a catalyst (D), wherein (A) contains the following polyether polyol (a), and the average particle size of (B) by volume is 0.1 to 100 μm. Polyether polyol (a): A polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 2.5 to 8.0, a hydroxyl value of 20 to 150, and a terminal oxyethylene unit content of 10 to 30% by mass.

2. The polyol composition according to claim 1, wherein the silica particles (B) are silica particles obtained from a calcined rice husk product.

3. The polyol composition according to claim 1, wherein at least a portion of (D) is a tertiary amine having a hydroxyl group.

4. A polyurethane foam obtained by reacting a polyol component, which includes the polyol composition according to any one of claims 1 to 3, with a polyisocyanate component.

5. A sound-absorbing and insulating material for vehicles made of polyurethane foam as described in claim 4.

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