JP4617793B2 - Soundproofing materials for automobile interior materials - Google Patents

Description

The present invention relates to a soundproofing material for automobile interior materials using a flexible polyurethane foam having a good sound absorption performance over a wide range from a low frequency to a medium frequency. Since the flexible polyurethane foam has excellent sound absorbing performance, when used as a soundproof material for automobiles, it is not necessary to use it together with a thermoplastic material as in the prior art. In addition, since it exhibits excellent soundproofing performance even when used alone, it is also effective in reducing the weight of automobiles.

  Conventionally, the dashboard that separates the engine room from the vehicle interior has been equipped with soundproofing materials for sound absorption and sound insulation to prevent vibrations and noise from entering the vehicle interior. Measures are taken. As this soundproofing material, a sound absorbing material made of a porous material such as polyester fiber or flexible polyurethane foam (hereinafter also referred to as soft foam) is integrated with a sound insulating material such as rubber, polypropylene sheet or vinyl chloride sheet. I came. In particular, flexible foam has been used as a sound absorbing material because it has an advantage that it can be produced at a lower cost than polyester fiber. For example, Patent Document 1 discloses a flexible foam having a specific level of air permeability and hardness and a method for producing the same, and Patent Document 2 discloses a method for producing a lightweight and soft foam having excellent soundproofing performance. ing.

  However, conventional flexible foams alone have insufficient sound absorption performance in the low-frequency region, so the sound insulation performance is improved by sticking a thermoplastic material such as rubber, which is mainly composed of polyolefin, to the flexible foam. There was a problem that had to be done. This has created further problems such as the need to consider the adhesion between the flexible foam and the thermoplastic material, and an increase in mass. In Patent Document 3, a soundproofing material composed of a flexible foam alone has been proposed. Although an excellent sound absorption performance is exhibited in a medium frequency to a high frequency region (2000 Hz or more), it is 1000 Hz or less, particularly in a low frequency region of 500 Hz or less. There was a problem that the sound absorption performance was insufficient.

Japanese Patent Publication No. 7-59389 JP-A-5-209036 Japanese Patent Laid-Open No. 10-121597

  Therefore, the present invention provides a method for producing a flexible polyurethane foam with improved low-frequency sound absorption performance, which has been insufficient in the past. In particular, there is provided a method for producing a flexible polyurethane foam, which is a flexible foam having a good sound absorption performance over a wide range from a low frequency to a medium frequency, and can be used as a soundproofing material for an automobile without being used in combination with other materials. .

  The present inventors have found that the sound absorption performance in the low frequency to medium frequency range is enhanced by controlling the air permeability of the flexible polyurethane foam, and have completed the present invention. The present invention is the following inventions.

A soundproofing material for automobile interior materials using a flexible polyurethane foam, wherein the flexible polyurethane foam has a high molecular weight polyoxyalkylene polyol having an average number of hydroxyl groups of 2 or more and a molecular weight per hydroxyl group (Mc) of 500 to 5,000. A flexible polyurethane foam obtained by foaming in a closed mold using a raw material composition (E) containing A), an organic polyisocyanate compound (B), a foaming agent (C), and a catalyst (D) . 8 to 70% by mass of the high molecular weight polyoxyalkylene polyol (A) has an average number of hydroxyl groups of 2 or more, a molecular weight per hydroxyl group (Mc) of 1800 to 2800, and a total unsaturation degree (USV) of 0.08 meq / a g or less polyoxyalkylene polyol (p), expanded to a thickness of 26mm using the raw material composition (E) A flexible polyurethane foam, air permeability 0.085 ³ / min or less, the sound absorption rate measuring method according to the normal incidence method, sound-absorbing characteristics of 500Hz is 0.3 or more, the sound absorption characteristics of 2000Hz is 0.55 or more, and a density of 80 deadening for automobile interior material, which is a ~120kg / ^{m 3.}

  The flexible polyurethane foam obtained by the present invention has improved sound absorption performance in a low frequency region of around 500 Hz, and is therefore suitable as a soundproof material for buildings or vehicles. In particular, the flexible polyurethane foam according to the present invention has the effect that the foam alone can be used as a soundproof material for automobiles, and is also effective in reducing the weight of automobiles.

(High molecular weight polyoxyalkylene polyol (A))
In the present invention, a high molecular weight polyoxyalkylene polyol (A) (hereinafter also referred to as polyol (A)) is used. The polyol (A) in the present invention is preferably obtained by ring-opening addition polymerization of alkylene oxide in the presence of an initiator and a catalyst. The average number of hydroxyl groups is 2 or more, and the molecular weight per hydroxyl group (Mc) is 500 or more. It is preferable.

  The molecular weight (Mc) per hydroxyl group of the polyol (A) is preferably 500 to 5000, more preferably 800 to 2800, and particularly preferably 850 to 2500. The polyol (A) may be a mixture of high molecular weight polyoxyalkylene polyols having a molecular weight (Mc) per hydroxyl group of 500 or more. In this case, the average molecular weight (Mc) per hydroxyl group is 500 to 5000. Preferably, it is 800-2800, more preferably 850-2500.

  If the average molecular weight (Mc) per hydroxyl group is less than 500, the flexible foam is not sufficiently cured and shrinkage tends to occur. This is not preferable, and if it exceeds 5000, the elasticity of the foam tends to be insufficient. In the present invention, a polyoxyalkylene polyol having a molecular weight per hydroxyl group of less than 500 may be used. Such a polyoxyalkylene polyol is classified as a crosslinking agent described later in the present invention.

  The polyol (A) is a polyol having an average number of hydroxyl groups of 2 or more. The polyol (A) may be a single type or a mixture of two or more types, or may be a polyol produced using the mixture as an initiator as described later. The average number of hydroxyl groups is preferably 2 to 8, more preferably 2 to 4, still more preferably 2.2 to 3.9, and most preferably 2.4 to 3.7. If the average number of hydroxyl groups in the polyol is less than 2, the foam becomes too soft and compression set deteriorates. If the number of hydroxyl groups exceeds 8, the foam becomes hard, and mechanical properties such as foam elongation deteriorate, and soundproofing performance is impaired. It tends to be. The number of hydroxyl groups in the polyol (A) is the same as the number of hydroxyl groups in the initiator used for the production.

  As the initiator used for producing the polyol (A), a compound having 2 to 8 active hydrogen atoms is preferable. For example, 2 to 8 valent polyhydric alcohols, polyhydric phenols, and amines are preferable. Specifically, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, dipropylene glycol, glycerin, trimethylolpropane. , Pentaerythritol, diglycerin, meso-erythritol, methyl glucoside, glucose, dextrose, sorbitol, sucrose and other polyhydric alcohols, bisphenol A, pyrogallol, hydroquinone and other polyhydric phenols, ethylenediamine, diethylenediamine, diaminodiphenylmethane, Hexamethylenediamine, propylenediamine and other polyamines, and amines such as condensation compounds obtained by condensation reaction of these polyamines with phenolic resins, novolac resins, etc. And the like. The polyhydric alcohols, polyhydric phenols, and amines are low molecular weight polyether polyols obtained by ring-opening addition polymerization of alkylene oxide in a small amount, and the molecular weight per hydroxyl group is about 200 to 500, preferably 200-350 compounds can also be used. Such a compound preferably has a molecular weight of 1200 or less.

  As the initiator, a compound having 2 to 4 active hydrogen atoms is more preferable, and a 2 to 4 valent polyhydric alcohol or a 2 to 4 valent low molecular weight polyether polyol is preferable. Among them, a polyol produced using a trihydric or higher polyhydric alcohol or a low molecular weight polyether polyol as an initiator is preferable because the sound insulation, foaming stability and physical properties of the flexible foam can be balanced. It is preferable to use it as at least a part of the polyol (A). Two or more of these initiators may be used in combination.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and styrene oxide. A combination of ethylene oxide and propylene oxide is preferable.

  When ethylene oxide and propylene oxide are combined, a method in which propylene oxide is subjected to ring-opening addition polymerization and then ethylene oxide is subjected to ring-opening addition polymerization to form an oxyethylene block chain at the terminal, and a mixture of propylene oxide and ethylene oxide is subjected to ring-opening addition polymerization A method of forming a random polymer chain by oxypropyleneoxyethylene (hereinafter referred to as random addition), a method of performing block ring-opening addition polymerization of ethylene oxide inside the molecular chain, or a method of performing random ring-addition polymerization of ethylene oxide after random addition. And a method of forming an oxyethylene block chain at the terminal and having an oxypropyleneoxyethylene random polymer chain.

  It is particularly preferable to use a polyol (A) having at least 5 to 25% by weight of a polyoxyethylene block chain, and particularly preferably 50 to 100% by mass of the polyol (A). .

  As the catalyst for the ring-opening addition polymerization of alkylene oxide, ordinary catalysts are used, for example, potassium hydroxide, sodium hydroxide, cesium hydroxide, phosphazenium compounds, boron trifluoride compounds, double metal cyanide complexes, etc. It is done. Of these, use of cesium hydroxide and a double metal cyanide complex is preferable because a polyol with low unsaturation can be produced, and a flexible foam having appropriate air permeability can be produced by using the polyol.

  The polyol (A) may contain fine polymer particles dispersed in the polyol. The polymer fine particles are those in which the polymer fine particles are stably dispersed in the base polyol as the dispersion medium. Examples of the polymer fine particles include addition polymer series polymers and condensation polymerization series polymers. For example, it consists of an addition polymerization system polymer such as acrylonitrile, styrene, alkyl methacrylate, alkyl acrylate, and other vinyl monomer homopolymers and copolymers, and a polycondensation polymer such as polyester, polyurea, polyurethane, and melamine resin. Of these, acrylonitrile, styrene or a copolymer thereof is preferable.

  The content of the polymer fine particles is preferably 0.1 to 10% by mass in the polyol (A), and preferably 1 to 10% by mass. The amount of the polymer fine particles need not be particularly large, and if it is too large, it is not inconvenient except for economical reasons. In addition, the presence of the polymer fine particles in the polyol (A) is not essential, but if present, it is effective for improving the hardness, air permeability and other physical properties of the foam. Therefore, it is preferable that it is 1% by mass or more, particularly 3% by mass or more. The method for dispersing the polymer fine particles includes a method in which the polymer fine particles are dispersed using the polyol (A) as a base polyol, and a method in which a part of the polyol (A) is dispersed as a base polyol to produce polymer fine particles. Any other method may be used.

  In the present invention, when the polyol (A) contains polymer-dispersed particles, the use ratio of the polyol (A) and the later-described polyol (p) is calculated based on the mass excluding the polymer fine particles.

(Polyoxyalkylene polyol (p))
In the present invention, a polyoxyalkylene polyol (p) (hereinafter also referred to as polyol (p)) is used as at least a part of the polyol (A). The polyol (p) is a polyoxy having a number of hydroxyl groups of 2 or more, a molecular weight per hydroxyl group (Mc) of 1800 to 2800, and a total unsaturation (USV) of 0.08 meq / g or less. It is an alkylene polyol.

  The molecular weight (Mc) per hydroxyl group of the polyol (p) is 1800-2800, preferably 1850-2500. When the molecular weight per hydroxyl group (Mc) is less than 1800, the flexible foam is not sufficiently cured and shrinkage tends to occur, which is not preferable. If the molecular weight is higher than 2800, the elasticity of the foam is insufficient.

The polyoxyalkylene polyol (p) has a total degree of unsaturation of 0.08 meq / g or less. If the total degree of unsaturation is greater than 0.08 meq / g, the air permeability of the flexible foam tends to exceed 0.085 m ³ / min and the sound absorption performance is poor, which is not preferable. The total degree of unsaturation is more preferably 0.06 meq / g or less, further preferably 0.05 meq / g or less, and most preferably 0.04 meq / g or less.

  In order to obtain a polyol having such a total unsaturation degree, it is preferable to use cesium hydroxide and a double metal cyanide complex as an alkylene oxide ring-opening addition polymerization catalyst, and it is particularly preferable to use a double metal cyanide complex. A well-known thing can be used as a double metal cyanide complex catalyst. A complex mainly composed of zinc hexacyanocobaltate is preferable, and one having ether and / or alcohol as an organic ligand is preferable. As the organic ligand, monoethylene glycol mono-tert-butyl ether, tert-butyl alcohol, glyme (ethylene glycol dimethyl ether) and the like are preferable.

The average number of hydroxyl groups of the polyol (p) is 2 or more. The polyol (p) may be a single type or a mixture of polyols having a molecular weight per hydroxyl group (Mc) of 1800 to 2800 and a total unsaturation (USV) of 0.08 meq / g or less. . Moreover, what was manufactured using the mixture as an initiator may be used. The average number of hydroxyl groups is preferably 2 to 8, more preferably 2 to 4, still more preferably 2.2 to 3.9, and most preferably 2.4 to 3.7. If the average number of hydroxyl groups in the polyol is less than 2, the foam becomes soft and compression set is deteriorated. If the number of hydroxyl groups exceeds 8, the foam becomes hard, and mechanical properties such as foam elongation are deteriorated, and soundproof performance is impaired.
Further, the polyol (p) preferably has a polyoxyethylene block chain at the end, and particularly preferably has 5 to 25% by mass.

  In this invention, it is preferable that the ratio of a polyol (p) is 5-100 mass% in a polyol (A). By containing 5 to 100% by mass of the polyol (p), a flexible foam having an appropriate hardness and an appropriate air permeability is obtained, and the foam strength is improved. The proportion of the polyol (p) is preferably 8 to 100% by mass, and most preferably 8 to 70% by mass. As described above, when the polyol (A) contains fine polymer particles, the ratio of the polyol (p) in the polyol (A) is calculated based on the mass excluding the fine polymer particles.

  In the present invention, in addition to the polyol (A), other high molecular weight polyols such as a polyester polyol may be used. However, the amount used is preferably 20 parts by mass or less, preferably 10 parts by mass or less, and particularly preferably not substantially used, with respect to 100 parts by mass of the polyol (A).

(Organic polyisocyanate compound (B))
The organic polyisocyanate compound (B) used in the present invention is not particularly limited, but is obtained by modifying aromatic, alicyclic or aliphatic polyisocyanates having two or more isocyanate groups; Modified polyisocyanates, etc .; a mixture of two or more of the above polyisocyanates. Specific examples include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (common name: crude MDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HMDI), and the like. These polyisocyanates, or their prepolymer-modified products, isocyanurate-modified products, urea-modified products, and carbodiimide-modified products. Of these, TDI, MDI, crude MDI, or modified products thereof are preferred.

  The amount of the organic polyisocyanate compound is usually represented by the isocyanate index ((isocyanate equivalent) / (total equivalent of all active hydrogens such as polyol, crosslinking agent, water) × 100), but the amount of polyisocyanate compound used in the present invention. The isocyanate index is preferably 50 to 110, more preferably 55 to 95.

(Foaming agent (C))
In the present invention, the foaming agent (C) is not particularly limited, but it is preferable to use at least one foaming agent selected from water and an inert gas. Specific examples of the inert gas include air, nitrogen, and carbon dioxide gas. It is particularly preferable to use water as the foaming agent. The amount of these blowing agents used is not particularly limited, but when water is used, polyol (A) (when using a high molecular weight polyol other than polyol (A), the total of polyol (A) and other high molecular weight polyols) 10 mass parts or less are preferable with respect to 100 mass parts, and 0.1-8 mass parts is more preferable. Other foaming agents can also be used in an appropriate amount according to demands such as foaming ratio.

(Catalyst (D))
When the polyol (A) and the organic polyisocyanate compound (B) are reacted, the catalyst (D) is used. Examples of the catalyst (D) include amine compounds and organometallic compounds.

  A tertiary amine catalyst having a molecular weight of 500 or less and having a hydroxyl group in the molecule is preferable from the viewpoint of prevention of fogging of automobile glass (fogging) and prevention of contamination (whitening) of polycarbonate resin used in automobile interiors. When the molecular weight is larger than 500, the reactivity between the hydroxyl group in the molecule and the organic polyisocyanate is not preferable.

Specific examples of the tertiary amine catalyst having a molecular weight of 500 or less and having a hydroxyl group in the molecule include N, N-dimethylaminoethoxyethoxyethanol, N, N-dimethylamino-6-hexanol, N, N-dimethylamino. Examples include, but are not limited to, ethoxyethanol, N, N-dimethylaminoethoxyethanol added with 2 moles of ethylene oxide, 5- (N, N-dimethyl) amino-3-methyl-1-pentanol, and the like.
Other tertiary amine catalysts can also be used, such as triethylenediamine, bis (2-dimethylaminoethyl) ether, N, N, N ′, N′-tetramethylhexamethylenediamine and the like.

  The amount of the amine-based catalyst used is 0.1 per 100 parts by mass of the polyol (A) (when using a high molecular weight polyol other than the polyol (A), the total of the polyol (A) and the other high molecular weight polyol). -5 mass parts is preferable. Even if the amount used exceeds or exceeds this range, the reaction curing between the isocyanate group and the active hydrogen group becomes unsatisfactory, and is particularly preferably 0.5 to 3.0 parts by mass.

  Moreover, an organometallic compound can also be used as a catalyst. Examples of organometallic compounds include organotin compounds, organobismuth compounds, organolead compounds, and organozinc compounds. For example, di-n-butyltin oxide, di-n-butyltin dilaurate, di-n-butyltin diacetate, di-n-octyltin oxide, di-n-octyltin dilaurate, monobutyltin trichloride, di-n-butyltin Examples thereof include dialkyl mercaptans and di-n-octyltin dialkyl mercaptans. The amount of these organometallic compounds used is 1.0 mass with respect to 100 parts by mass of polyol (A) (when using a high molecular weight polyol other than polyol (A), the total of polyol (A) and other high molecular weight polyols). Less than part, especially 0.005-1.0 part by mass is preferable.

(Other)
In the present invention, a crosslinking agent can also be used. As the crosslinking agent, a compound having two or more active hydrogen-containing groups selected from a hydroxyl group, a primary amino group, and a secondary amino group is preferable. The number of active hydrogen-containing groups is preferably 2-8. Moreover, the molecular weight per active hydrogen-containing group of the crosslinking agent is preferably 30 to less than 500, more preferably 30 to 200. Two or more crosslinking agents may be used in combination.

  Specific examples of the crosslinking agent include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, and pentane. Erythritol, diglycerin, monoethanolamine, diethanolamine, triethanolamine, bisphenol A, ethylenediamine, 3,5-diethyl-2,4 (or 2,6) -diaminotoluene (DETDA), 2-chloro-p-phenylenediamine (CPA), 3,5-bis (methylthio) -2,4 (or 2,6) -diaminotoluene, 1-trifluoromethyl-3,5-diaminobenzene, 1-trifluoromethyl-4-chloro-3 , 5-Di Minobenzene, 2,4-toluenediamine, 2,6-toluenediamine, bis (3,5-dimethyl-4-aminophenyl) methane, 4,4'-diaminodiphenylmethane, m-xylylenediamine, 1,4-diamino Examples of the compound include hexane, 1,3-bis (aminomethyl) cyclohexane, and isophoronediamine. Low molecular weight polyoxyalkylene polyols can also be used. 0.1-20 mass parts is preferable with respect to 100 mass parts of polyols (A), and, as for a crosslinking agent, 0.5-10 mass parts is especially preferable.

  In addition, foam stabilizers are often used to form good bubbles. Examples of the foam stabilizer include a silicone foam stabilizer and a fluorine-containing compound foam stabilizer. Other optional emulsifiers; antioxidants such as antioxidants and ultraviolet absorbers; fillers such as calcium carbonate and barium sulfate; various known types such as plasticizers, colorants, flame retardants, antifungal agents, and foam breakers Additives and auxiliaries can be used as necessary.

(Breathable)
The present invention relates to a metal mold sealed with a raw material composition (E) containing a high molecular weight polyoxyalkylene polyol (A), an organic polyisocyanate compound (B), a foaming agent (C), and a catalyst (D). The flexible polyurethane foam produced by foaming at a thickness of 26 mm using the raw material composition (E) has a breathability of 0.085 m ³ / min or less. . Hereinafter, the flexible polyurethane foam foamed to a thickness of 26 mm is also referred to as a 26 mm thickness sample. This is obtained by foaming using a closed mold having a height of 26 mm.

The air permeability refers to a numerical value measured by a method based on JIS K6400B method (1997). By using the raw material composition (E) having a gas permeability of 0.085 m ³ / min or less when a 26 mm-thickness sample is used, the sound absorption performance in the low frequency region, which has been insufficient with a conventional flexible polyurethane foam, is excellent. A flexible polyurethane foam that does not impair the sound absorption performance in the middle frequency range, which is originally good, can be obtained. Breathable when a 26mm thickness sample is preferably not more than 0.030 m ³ / min, more preferably less preferably 0.025 m ³ / min.

(Characteristic)
In the present invention, in the sound absorption measurement method in the normal incidence method of the flexible polyurethane foam foamed to a thickness of 26 mm using the raw material composition (E), the sound absorption performance at 500 Hz is 0.3 or more, and the sound absorption characteristic at 2000 Hz is It is preferable that it is 0.55 or more.

  Sound absorption characteristics can be measured by a method based on JIS A1405 method (1963). When the sound absorption characteristic at 500 Hz is smaller than 0.3, the sound absorption performance at low frequencies is insufficient, and it is unavoidable to combine with other materials as a sound insulation material for automobiles. When the sound absorption performance at 2000 Hz is less than 0.55, the sound absorption at medium frequency is insufficient, and the performance is inferior as a soundproof material, particularly a soundproof material for automobiles.

  More preferably, the sound absorption characteristic at 500 Hz is 0.35 or more, and 0.4 or more is particularly preferable. The sound absorption characteristic at 2000 Hz is preferably 0.57 or more, and particularly preferably 0.6 or more.

  Moreover, it is preferable that F hardness of the flexible foam of this invention is 80 or less. If the F hardness is 80 or less, a good soundproofing effect is obtained, and if the F hardness is greater than 80, the soundproofing effect is inferior. The F hardness is preferably 40 or more.

Furthermore foam density of the flexible polyurethane foam of the present invention is preferably 120 kg / ^{m 3} or less, it is preferable that 60~120kg / ^{m 3.} If the foam density exceeds this range, the mass of the flexible foam increases, so that it is not possible to follow the recent reduction in weight of automobiles. The foam density is particularly preferably 80 to 100 kg / m ³ . The rebound resilience is preferably 30 to 50%. On the other hand, if the resilience elastic modulus is larger than this range, the energy attenuation of the foam is lowered and the acoustic characteristics are lowered, which is not preferable.

(Molding method)
Molding of the flexible foam in the method of the present invention is a method in which the raw material composition (E) is directly injected into a sealed mold using a low-pressure foaming machine or a high-pressure foaming machine (that is, a reaction injection molding method) or is injected into the mold. A method of post-sealing is preferred.

  The high pressure foaming machine is preferably a mixture of two ordinary liquids. In this case, an organic polyisocyanate compound is used for one of the two liquids, and a mixture of all raw materials other than the organic polyisocyanate compound (usually called a polyol system liquid) is used for the other liquids. In some cases, a reactive mixture may be formed and injected with a total of three or more components including a catalyst or a foam stabilizer (usually dispersed or dissolved in a part of a high molecular weight polyol) and a foaming agent as separate components.

  The flexible foam of the present invention is usually produced by a cold cure method, but can also be produced by a method other than the cold cure method, for example, including a heating step.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to this.

  Molecular weight per hydroxyl group (Mc), hydroxyl group number, oxyethylene (EO) group of polyols (p-1) to (p-2) and (A-1) to (A-5) used in Examples and Comparative Examples Table 1 shows the content (unit: mass%), the total unsaturation (USV) (unit: meq / g), and the polymerization catalyst. In Table 1, KOH represents a potassium hydroxide catalyst, CsOH represents a cesium hydroxide catalyst, and DMC represents a zinc hexacyanocobaltate-monoethylene glycol mono-t-butyl ether complex catalyst. The degree of unsaturation was measured by a method based on JIS K 1557 method (1970). Polyol (p-1) is a compound having a molecular weight of 1000 obtained by ring-opening addition polymerization of propylene oxide (PO) to glycerin as an initiator, and using KOH after ring-opening addition polymerization of PO in the presence of DMC. EO was produced by ring-opening addition polymerization. The polyol (p-2) was produced by subjecting PO to ring-opening addition polymerization and EO to ring-opening addition polymerization in the presence of CsOH using glycerol as an initiator. Polyols (A-1) and (A-5) were produced by subjecting PO to ring-opening addition polymerization and EO to ring-opening addition polymerization in the presence of KOH using glycerol as an initiator. The polyol (A-2) was produced by ring-opening addition polymerization of PO using KOH with a mixture of glycerin and sucrose as an initiator and then ring-opening addition polymerization of EO. The polyol (A-3) was produced by ring-opening addition polymerization of a mixture of PO and EO in the presence of KOH using glycerol as an initiator. The polyol (A-4) was produced by ring-opening addition polymerization of PO in the presence of KOH using glycerol as an initiator. Other raw materials are shown in Table 2.

(Examples 1 to 11)
The upper and lower mold temperatures of an aluminum mold having a length of 400 mm and a height of 26 mm were heated to 60 ° C. Among the raw materials having the blending amounts shown in Table 3 and Table 4, the mixture of all raw materials other than the organic polyisocyanate compound (polyol system liquid) and the organic polyisocyanate compound liquid were adjusted to a liquid temperature of 25 ± 1 ° C., respectively. A predetermined amount of the organic polyisocyanate compound liquid was added to the polyol system liquid, and the mixture was stirred and mixed for 5 seconds with a high speed mixer (3000 rpm), poured into a mold at room temperature, sealed, and foamed and cured to produce a flexible polyurethane foam. . After 3 minutes, the flexible foam was taken out of the mold and left in a room adjusted to room temperature (23 ° C.) and humidity (50%) for 24 hours or more, and various physical properties were measured. The measurement results are shown in Tables 3 and 4. In addition, the measuring method of foam physical properties is based on the following, and the standard used for measuring the physical properties of the flexible foam is shown below. Examples 1 to 8 are examples, and examples 9 to 11 are comparative examples. Moreover, in Tables 3-4, the numerical value of a prescription column shows the mass%.

Foam density (unit: kg / m ³ ), air permeability (unit: m ³ / min) is a method based on JIS K6400B method (1997), normal incident sound absorption characteristics is a method based on JIS A1405 method (1963) Measured by using a device: Bruel & Kjaer vertical incident sound absorption measuring tube Model No. 4206 Analysis software: Winzac manufactured by Nittobo Acoustic Engineering Co., Ltd. Power amplifier: Yamaha A100a, microphone amplifier: Bruel & Kjaer Model No. 2691

  The flexible foams obtained in Examples 1 to 8 have good sound absorption performance, and particularly good sound absorption performance at 500 Hz (low frequency region). Further, the foam density and F hardness also show appropriate values. On the other hand, Examples 9 to 11 tend to be inferior in the low frequency region sound absorption performance.

The flexible polyurethane foam obtained by the present invention has improved sound absorption characteristics in a low frequency region of around 500 Hz, and is therefore suitable as a soundproof material for buildings or vehicles. It is particularly suitable as a soundproof material for vehicles such as automobiles.

Claims (6)

A soundproofing material for automobile interior materials using flexible polyurethane foam,
The flexible polyurethane foam has a high molecular weight polyoxyalkylene polyol (A) having an average number of hydroxyl groups of 2 or more and a molecular weight (Mc) per hydroxyl group of 500 to 5000, an organic polyisocyanate compound (B), a foaming agent (C), And a flexible polyurethane foam obtained by foaming in a closed mold using a raw material composition (E) containing a catalyst (D) ,
8 to 70 mass% of the high molecular weight polyoxyalkylene polyol (A) has an average number of hydroxyl groups of 2 or more, a molecular weight per hydroxyl group (Mc) of 1800 to 2800, and a total unsaturation degree (USV) of 0.08 meq / g. It is the following polyoxyalkylene polyol (p),
The flexible polyurethane foam foamed to a thickness of 26 mm using the raw material composition (E) has an air permeability of 0.085 m ³ / min or less , and a sound absorption characteristic at 500 Hz in a sound absorption coefficient measurement method by a normal incidence method is 0.3. As described above, a soundproofing material for automobile interior materials having a sound absorption characteristic of 2000 Hz of 0.55 or more and a density of 80 to 120 kg / m ³ . The automobile interior according to claim 1, wherein the polyol (p) is a polyoxyalkylene polyol obtained by ring-opening addition polymerization of an alkylene oxide in the presence of a double metal cyanide complex catalyst or a cesium hydroxide catalyst and an initiator. Soundproofing material. The soundproofing material for automobile interior materials according to claim 1 or 2, wherein the polyol (p) has 5 to 25 mass% of a polyoxyethylene block chain at a terminal.   The soundproofing material for automobile interior materials according to any one of claims 1 to 3, wherein the organic polyisocyanate compound (B) is used in an isocyanate index of 50 to 110. The soundproofing material for automobile interior materials according to any one of claims 1 to 4 , wherein the foaming agent (C) is one kind of foaming agent selected from water and an inert gas . The soundproofing material for automobile interior materials according to any one of claims 1 to 5, wherein the flexible polyurethane foam has an F hardness of 40 to 80.