JP2013040330A - Additive for strength improvement for producing polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive for strength improvement capable of producing a polyurethane foam having a high mechanical property, and a polyol composition for the production of the polyurethane foam that contains the additive for strength improvement.SOLUTION: The additive for strength improvement for producing polyurethane foam (K) includes a structure in which a polycarboxylic acid and a compound that has at least two active hydrogens (H) are condensed, wherein the polycarboxylic acid contains a trivalent or more aromatic carboxylic acid (A), and the additive for strength improvement has at least three structures induced from (A) in one molecule of the additive for the strength improvement.

Description

  The present invention relates to a strength improver for producing polyurethane foam.

In recent years, environmental considerations and cost reduction demands are strong, and there is a demand for lower density polyurethane foam. For example, in a vehicle application, a low density of flexible polyurethane foam is required to meet fuel efficiency regulations. In addition, in the heat insulating material application, weight reduction is desired for cost reduction and environmental consideration.
At present, the amount of water used as a foaming agent tends to increase to meet the demand for lower density. Increasing the amount of water used (Non-Patent Document 1, etc.) can increase the amount of carbon dioxide generated during foam production and is effective in reducing the density of flexible polyurethane foam. As the hardness decreases, the foam hardness decreases. Specific techniques for improving the hardness of polyurethane foam include a method of increasing the amount of the crosslinking agent used (Non-patent Document 1) and a method of dispersing a polymer in a resin (Patent Document 1). However, there are still problems such as insufficient mechanical properties such as elongation and tensile strength of the flexible polyurethane foam, and a flexible polyurethane foam that improves the hardness and maintains the mechanical properties is desired. Yes.
In order to reduce the density, it has also been proposed to use a relatively large amount of water as a blowing agent together with a small amount of methylene chloride. However, this method increases the hardness of the resulting foam, and this method cannot be employed from the viewpoint of obtaining a flexible polyurethane foam. Therefore, a method using monool or diol as a component of polyol has also been proposed. However, in this method, there arises a problem that other physical properties are impaired such as an increase in compression residual strain of the foam obtained (Patent Document 2).

JP-A-9-309937 JP-A-6-65346

Keiji Iwata, "Polyurethane Resin Handbook", Nikkan Kogyo, May 20, 1987, 1st Edition, 32 pages

  An object of the present invention is to provide a polyurethane foam-producing strength improver that can produce a polyurethane foam having high mechanical properties (elongation rate, tensile strength, tear strength, compressive strength), and a polyurethane foam containing the strength improver. A polyol composition for production and a strength improver or a method for producing a polyurethane foam using the polyol composition.

  As a result of intensive investigations to solve these problems, the present inventors have found that a high mechanical property (elongation rate, tensile strength, compressive strength) can be obtained by using a strength improver for producing polyurethane foam having a specific structure. And the present invention has been reached.

  That is, the first invention of the present invention is a strength improver having a structure in which a polycarboxylic acid and an active hydrogen-containing compound (H) having two or more active hydrogens are condensed, and the polycarboxylic acid is trivalent or higher. This is a strength improver (K) for producing a polyurethane foam containing an aromatic carboxylic acid (A) and having 3 or more structures derived from (A) in one molecule of the strength improver.

Moreover, 2nd invention of this invention is a polyol composition (B) for polyurethane foam manufacture containing the said strength improving agent (K) for polyurethane foam manufacture, and polyol (P).
The third invention of the present invention is a foaming agent comprising the above-mentioned strength improver for producing polyurethane foam (K) or the above-mentioned polyol composition for producing polyurethane foam (B) and the organic polyisocyanate component (D). And a process for producing a polyurethane foam obtained by reacting in the presence of a catalyst.

  When the strength improver for producing polyurethane foam of the present invention is used, a polyurethane foam having high mechanical properties (elongation rate, tensile strength, compressive strength) can be obtained.

  The strength improver for producing polyurethane foam of the present invention is a strength improver having a structure in which a polycarboxylic acid and an active hydrogen-containing compound (H) having two or more active hydrogens are condensed, and the polycarboxylic acid is trivalent or higher. The aromatic carboxylic acid (A) is included, and one molecule of the strength improver has three or more structures derived from (A). In order to react polycarboxylic acid with (H) to obtain (K), any known method such as a condensation reaction may be used.

  Examples of the active hydrogen-containing compound (H) having two or more active hydrogens include a hydroxyl group-containing compound, an amino group-containing compound, and a carboxyl group-containing compound (excluding polyvalent carboxylic acid. A compound having two or more active hydrogen-containing functional groups in the molecule, such as a carboxylic acid (F), a thiol group-containing compound, and a phosphoric acid compound. It is preferable to react one kind of these active hydrogen-containing compounds with a polycarboxylic acid to obtain a strength improver (K) in order to obtain the foam strength improving effect without variation.

Examples of the hydroxyl group-containing compound include divalent to octavalent polyhydric alcohols and polyhydric phenols. Specifically, ethylene glycol, propylene glycol, 1,3 and 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, diethylene glycol, neopentyl glycol, cyclohexanediol, cyclohexanedimethanol, 1, Dihydric alcohols such as 4-bis (hydroxymethyl) cyclohexane and 1,4-bis (hydroxyethyl) benzene; trihydric alcohols such as glycerin and trimethylolpropane; pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipenta 4- to 8-valent alcohols such as erythritol, sucrose, glucose, mannose, fructose, methylglucoside and derivatives thereof; hydroquinone, bisphenol A, bisphenol F, bisphenol Polyphenols such as S, 1-hydroxynaphthalene, 1,3,6,8-tetrahydroxynaphthalene, 1,4,5,8-tetrahydroxyanthracene and 1-hydroxypyrene; polybutadiene polyol; castor oil-based polyol A (co) polymer of hydroxyalkyl (meth) acrylate and a polyfunctional (for example, 2 to 100 functional group) polyol such as polyvinyl alcohol, a condensate of phenol and formaldehyde (novolak), and US Pat. No. 3,265,641 Examples include polyphenols.
(Meth) acrylate means methacrylate and / or acrylate, and the same applies hereinafter.

  Examples of the amino group-containing compound include amines, polyamines and amino alcohols. Specifically, ammonia; monoamines such as C1-C20 alkylamine (butylamine and the like) and aniline; aliphatic polyamines such as ethylenediamine, hexamethylenediamine and diethylenetriamine; heterocyclics such as piperazine and N-aminoethylpiperazine Polyamines; alicyclic polyamines such as dicyclohexylmethanediamine and isophoronediamine; aromatic polyamines such as phenylenediamine, tolylenediamine and diphenylmethanediamine; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; and dicarboxylic acids Polyamide polyamine obtained by condensation with excess polyamine; polyether polyamine; hydrazine (such as hydrazine and monoalkylhydrazine), dihydrazide ( Etc. Haq acid dihydrazide and dihydrazide terephthalate), guanidine (butyl guanidine and 1-cyanoguanidine, etc.); dicyandiamide; and the like.

  Examples of the carboxyl group-containing compound include aliphatic monocarboxylic acids such as acetic acid and propionic acid; aromatic monocarboxylic acids such as benzoic acid and the like.

  Examples of the thiol group-containing compound include divalent to octavalent polyvalent thiols. Specific examples include ethanedithiol and 1,6-hexanedithiol.

  Examples of phosphoric acid compounds include phosphoric acid, phosphorous acid, and phosphonic acid.

  As (H), a compound having two or more active hydrogen-containing functional groups (hydroxyl group, amino group, carboxyl group, thiol group, phosphate group, etc.) in the molecule can also be used.

  Moreover, as (H), the alkylene oxide adduct of the said active hydrogen containing compound can also be used.

  The alkylene oxide to be added (hereinafter abbreviated as AO) includes AO having 2 to 6 carbon atoms, such as ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1, 3-propyleneoxide, 1,2-butylene oxide, 1,4-butylene oxide and the like can be mentioned. Of these, PO, EO, and 1,2-butylene oxide are preferable from the viewpoints of properties and reactivity. When two or more types of AO are used (for example, PO and EO), block addition or random addition may be used, or a combination thereof may be used.

The aliphatic polycarboxylic acid means a compound that satisfies the following (1) and (2).
(1) One molecule has two or more carboxyl groups.
(2) The carboxyl group is not directly bonded to the aromatic ring.

  Aliphatic polycarboxylic acids include succinic acid, adipic acid, sebacic acid, maleic acid and fumaric acid.

The aromatic polycarboxylic acid means a compound that satisfies the following (1) to (3).
(1) One molecule has one or more aromatic rings.
(2) The number of carboxyl groups in one molecule is 2 or more.
(3) The carboxyl group is directly bonded to the aromatic ring.

  Aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, 2,2'-bibenzyldicarboxylic acid, trimellitic acid, hemilitic acid, trimesic acid, pyromellitic acid and naphthalene-1,4 dicarboxylic acid, naphthalene Examples include aromatic polycarboxylic acids having 8 to 18 carbon atoms such as -2,3,6 tricarboxylic acid, diphenic acid, 2,3-anthracene dicarboxylic acid, 2,3,6-anthracentricarboxylic acid and pyrene dicarboxylic acid.

  Moreover, when performing condensation reaction of polycarboxylic acid and an active hydrogen containing compound, the anhydride and lower alkyl ester of polycarboxylic acid can also be used.

  From the viewpoint of handling the strength improver and improving the mechanical properties (elongation rate, tensile strength, compressive strength) of polyurethane foam, (H) constituting (K) includes a hydroxyl group-containing compound, an amino group-containing compound, and the like. Polyester compounds obtained by condensation reaction of AO adducts and active hydrogen-containing compounds with polycarboxylic acids are preferred, ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitol, sucrose, benzyl alcohol, methylamine, Ethylamine, butylamine, phenylamine, their EO and / or PO adducts and condensates of these active hydrogen compounds with phthalic acid and / or isophthalic acid are preferred.

  (H) has 2 or more active hydrogens, and (K) preferably 2 to 8, more preferably 2 to 4 from the viewpoint of ease of handling during synthesis.

As polycarboxylic acid which comprises (K), the polycarboxylic acid mentioned above can be used, The aliphatic polycarboxylic acid mentioned above and aromatic polycarboxylic acid are contained.
The polycarboxylic acid constituting (K) includes a trivalent or higher aromatic polycarboxylic acid (A). The aromatic ring in (A) is composed of carbon atoms. The substituent of the aromatic ring may be a hydrogen atom or another substituent, but at least one substituent is preferably a hydrogen atom, that is, the aromatic ring of the aromatic polycarboxylic acid (A) is an aromatic ring. From the viewpoint of improving the mechanical strength, it is preferable to have at least one hydrogen atom bonded to the constituent carbon atoms.

  Other substituents are alkyl group, vinyl group, allyl group, cycloalkyl group, halogen atom, amino group, carbonyl group, carboxyl group, hydroxyl group, hydroxyamino group, nitro group, phosphino group, thio group, thiol group Aldehyde group, ether group, aryl group, amide group, cyano group, urea group, urethane group, sulfone group, ester group and azo group. From the viewpoint of improving mechanical properties (elongation rate, tensile strength, compressive strength) and cost, the other substituents are preferably alkyl groups, vinyl groups, allyl groups, amino groups, amide groups, urethane groups and urea groups. .

  As the arrangement of the substituents on the aromatic ring of (A), from the viewpoint of improving the mechanical properties, two carbonyl groups are adjacent and substituted between the third carbonyl group and the first or second carbonyl group. A structure in which hydrogen is arranged as a group is preferable.

  Examples of the trivalent or higher aromatic polycarboxylic acid (A) constituting (K) include trimellitic acid, hemititic acid, trimesic acid, pyromellitic acid, naphthalene-2,3,6 tricarboxylic acid, and 2,3,6. -C8-C18 aromatic polycarboxylic acid, such as anthracentricarboxylic acid.

  From the viewpoint of handling the strength improver and improving the mechanical properties (tensile strength, tear strength, compressive strength) of the polyurethane foam, (A) used in (K) is preferably a monocyclic compound, more preferably tricyclic. It is merit acid and pyromellitic acid.

  The valence of the carboxylic acid of the aromatic polycarboxylic acid (A) is not less than 3, and (K) is preferably 3 to 5 and more preferably 3 to 4 from the viewpoint of ease of handling during synthesis. is there.

  From the viewpoint of improving mechanical strength, the trivalent or higher aromatic polycarboxylic acid is preferably used in an amount of 25 to 100% by weight, more preferably 50 to 100% by weight, based on the weight of the polycarboxylic acid. preferable

  The strength improver (K) has three or more structures derived from (A) in one molecule. The number of structures derived from (A) in one molecule of (K) is preferably from 3 to 10, more preferably from 3 to 8, from the viewpoint of the effect of improving mechanical strength.

The hydroxyl value (mgKOH / g) of the strength improver (K) for producing the polyurethane foam of the present invention is preferably from 30 to 400, more preferably from 40 to 390, from the viewpoint of handling (viscosity) and tensile strength during molding. Next, it is more preferably 50 to 380.
In the present invention, the hydroxyl value is measured in accordance with JISK-1557.

The aromatic ring concentration (mmol / g) of the strength improver (K) for producing the polyurethane foam of the present invention is preferably 0.1 to 10.0 from the viewpoint of improving mechanical properties (elongation rate and tensile strength), It is preferably 0.2 to 9.5, and more preferably 0.3 to 9.0.
In addition, the aromatic ring concentration of (K) means the number of moles of the aromatic ring in 1 g of the strength improver (K).

The strength improver (K) for producing a polyurethane foam according to the present invention preferably has no acidic group in order to ensure stability at the time of producing the polyurethane foam, and preferably has an acid value of 2.0 mgKOH / g or less.
The acid value as used herein means the number of milligrams of potassium hydroxide required to neutralize the free acid contained in 1 g of the sample. (K) 5 to 10 g can be dissolved in 100 ml of a neutral methanol / acetone 1: 1 mixed solvent, titrated with a 0.1N aqueous potassium hydroxide solution, and calculated from the titer required for neutralization.

  The polyol composition (B) for producing a polyurethane foam of the present invention comprises the above-described strength improver (K) for producing a polyurethane foam and a polyol (P).

  Specific examples of the polyol (P) include known polyols such as the following polyhydric alcohols, polyether polyols, and polyester polyols other than (K).

Examples of the polyhydric alcohol include a dihydric alcohol having 2 to 20 carbon atoms, a trihydric alcohol having 3 to 20 carbon atoms, and a 4 to 8 alcohol having 5 to 20 carbon atoms.
Examples of the dihydric alcohol having 2 to 20 carbon atoms include aliphatic diols (ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc.) and alicyclic Diols (cyclohexanediol and cyclohexanedimethanol etc.) are mentioned.
Examples of the trihydric alcohol having 3 to 20 carbon atoms include aliphatic triols (such as glycerin and trimethylolpropane).
Examples of the 4- to 8-valent polyhydric alcohol having 5 to 20 carbon atoms include aliphatic polyols (pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol and the like, and saccharides (sucrose, glucose, mannose, fructose, methyl). Glucoside and derivatives thereof).

  Examples of the polyether polyol include AO adducts of polyhydric alcohols. Examples of AO include the aforementioned AO, and PO, EO, and 1,2-butylene oxide are preferable from the viewpoint of properties and reactivity. When two or more types of AO are used (for example, PO and EO), block addition or random addition may be used, or a combination thereof may be used.

  Polyester polyols include polyhydric hydroxyl group-containing compounds (the above polyhydric alcohols and polyether polyols), aromatic polycarboxylic acids (such as those described above) and aliphatic polycarboxylic acids (such as those described above), and anhydrides thereof. Products and condensation reaction products of these lower alkyl (alkyl group having 1 to 4 carbon atoms) esters such as esters (phthalic anhydride and dimethyl terephthalate, etc.); And AO addition reaction products; these AO (EO, PO, etc.) addition reaction products; polylactone polyols {obtained by ring-opening polymerization of lactones (e.g., ε-caprolactone etc.) using the polyhydric alcohol as an initiator. And polycarbonate polyols (for example, the polyhydric alcohols and alkylene cars) Reactant) or the like and sulfonates and the like.

  Examples of other polyols other than these include polydiene polyols such as polymer polyols and polybutadiene polyols and hydrogenated products thereof; acrylic polyols, JP-A 58-57413 and JP-A 58-57414, etc. Hydroxyl group-containing vinyl polymers; natural oil polyols such as castor oil; modified natural oil polyols; and the like.

  The content of the strength improver (K) for polyurethane foam production based on the weight of the polyol composition (B) for polyurethane foam production is 0.1 or more from the viewpoint of improving mechanical properties (elongation rate and tensile strength). The amount is preferably less than 100% by weight, more preferably 0.5 to 80% by weight, and particularly preferably 1.0 to 60% by weight. In the present invention, when the polymer polyol to be used contains the strength improver (K), it is handled as if the polyol composition (B) contains (K).

  In producing the polyol composition (B) for producing the polyurethane foam, any known method may be used for mixing the strength improver (K) and the polyol (P).

In the polyurethane foam production method of the present invention, the polyurethane foam strength improver (K) or the polyurethane foam production polyol composition (B) and the organic polyisocyanate component (D) are reacted in the presence of a blowing agent and a catalyst. To form a polyurethane foam.
When (K) is used alone, that is, when (K) is not used in combination with the polyol (P), it is preferable that (K) has a hydroxyl group.

  As the organic polyisocyanate component (D), all organic polyisocyanates usually used in polyurethane foams can be used. Aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, araliphatic polyisocyanates, these Modified products (urethane groups, carbodiimide groups, allophanate groups, urea groups, burette groups, isocyanurate groups, oxazolidone group-containing modified products, etc.) and mixtures of two or more of these.

  Aromatic polyisocyanates include aromatic diisocyanates having 6 to 16 carbon atoms (excluding carbons in NCO groups; the following polyisocyanates are also the same), aromatic triisocyanates having 6 to 20 carbon atoms, and crude products of these isocyanates. Thing etc. are mentioned. Specific examples include 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4′- and 4,4′-diphenylmethane diisocyanate ( MDI), polymethylene polyphenylene polyisocyanate (crude MDI), naphthylene-1,5-diisocyanate, and triphenylmethane-4,4 ′, 4 ″ -triisocyanate.

  Examples of the aliphatic polyisocyanate include aliphatic diisocyanates having 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include alicyclic diisocyanates having 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate.

Examples of the araliphatic isocyanate include araliphatic diisocyanates having 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate and α, α, α ′, α′-tetramethylxylylene diisocyanate.
Specific examples of the modified polyisocyanate include carbodiimide-modified MDI.

  Among these, aromatic polyisocyanates are preferable from the viewpoints of reactivity and mechanical properties (tensile strength, tear strength, compressive strength) of polyurethane foam, and more preferably TDI, crude TDI, MDI, and crude MDI. And modified products of these isocyanates, particularly preferably TDI, MDI and crude MDI.

  Examples of the foaming agent include water, liquefied carbon dioxide, and low boiling point compounds having a boiling point of −5 to 70 ° C.

  Low boiling point compounds include hydrogen atom-containing halogenated hydrocarbons and low boiling point hydrocarbons. Specific examples of the hydrogen atom-containing halogenated hydrocarbon and low boiling point hydrocarbon include methylene chloride, HCFC (hydrochlorofluorocarbon) (HCFC-123, HCFC-141b, HCFC-142b, etc.); HFC (hydrofluorocarbon) (HFC- 152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa and HFC-365mfc), butane, pentane and cyclopentane.

  Among these, from the viewpoint of moldability, water, liquefied carbon dioxide, methylene chloride, cyclopentane, HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc and It is preferable to use a mixture of two or more of these as a foaming agent.

  Among the foaming agents, the amount of water used is the polyol component used for polyurethane foam production {strength improver for polyurethane foam production (K) and polyurethane foam production for the purpose of suppressing foam density during foam formation and scorch generation. The polyol composition (B)} is preferably 1.0 to 8.0 parts by weight, more preferably 1.5 to 7.0 parts by weight, based on 100 parts by weight. The amount of the low boiling point compound used is preferably 30 parts by weight or less, more preferably 5 to 25 parts by weight, with respect to 100 parts by weight of the polyol component, from the viewpoint of poor molding. The liquefied carbon dioxide gas is preferably 30 parts by weight or less, more preferably 1 to 25 parts by weight.

  As the catalyst, any catalyst that promotes the urethanization reaction can be used. Tertiary amine {triethylenediamine (1,4-diazabicyclo [2.2.2] octane), N-ethylmorpholine, diethylethanolamine, tetra Methylethylenediamine, 1,2-dimethylimidazole, 1-methylimidazole, 1,8-diazabicyclo- [5,4,0] -undecene-7, bis (N, N-dimethylamino-2-ethyl) ether and N, N, N ′, N′-tetramethylhexamethylenediamine, etc.] and / or carboxylic acid metal salts (potassium acetate, potassium octylate, stannous octylate, dibutylstannic dilaurate, lead octylate, etc.) Can be mentioned. The amount of the catalyst used is 0.01 to 5.0 parts by weight with respect to 100 parts by weight of the polyol component used in the production of polyurethane foam from the viewpoint of improving mechanical properties (tensile strength, tear strength, compressive strength) Is more preferable, and 0.1 to 2.0 parts by weight is more preferable.

  As the foam stabilizer, all those used in the production of ordinary polyurethane foams can be used. Dimethylsiloxane foam stabilizers [“SRX-253”, “PRX-607”, etc., manufactured by Toray Dow Corning Co., Ltd.] And polyether-modified dimethylsiloxane-based foam stabilizer [“L-540”, “SZ-1142”, “L-3601”, “SRX-294A”, “SH-193” manufactured by Toray Dow Corning Co., Ltd.] “SZ-1720”, “SZ-1675t”, “SF-2936F” and “B-4900” manufactured by Degussa Japan Co., Ltd.]. The amount of the foam stabilizer used is 0.5 to 5.0 parts by weight with respect to 100 parts by weight of the polyol component from the viewpoint of mechanical properties (elongation rate, tensile strength), mechanical properties over time and foam discoloration. Is more preferable, and 1.0 to 3.0 parts by weight is more preferable.

In the method for producing the polyurethane foam of the present invention, if necessary, other auxiliary agents described below may be used and reacted in the presence thereof.
Other auxiliaries include colorants (dyes and pigments), plasticizers (phthalates and adipates, etc.), organic fillers (synthetic short fibers, hollow microspheres made of thermoplastic or thermosetting resins, etc.) And known auxiliary components such as flame retardants (such as phosphate esters and halogenated phosphate esters), anti-aging agents (such as triazole and benzophenone), and antioxidants (such as hindered phenol and hindered amine).

  As the addition amount of these auxiliaries, the colorant is preferably 1 part by weight or less with respect to 100 parts by weight of the polyol component. The plasticizer is preferably 10 parts by weight or less, more preferably 5 parts by weight or less. The organic filler is preferably 50 parts by weight or less, more preferably 30 parts by weight or less. The flame retardant is preferably 30 parts by weight or less, and more preferably 2 to 20 parts by weight. The anti-aging agent is preferably 1 part by weight or less, more preferably 0.01 to 0.5 part by weight. The antioxidant is preferably 1 part by weight or less, more preferably 0.01 to 0.5 part by weight. The total amount of auxiliary agent used is preferably 50 parts by weight or less, more preferably 0.2 to 30 parts by weight.

  In the production method of the present invention, the isocyanate index (index) [(equivalent ratio of NCO group / active hydrogen atom-containing group) × 100] in the production of polyurethane foam is determined from the viewpoint of moldability, mechanical properties (tensile strength, tearing). From the viewpoint of strength and compressive strength, 70 to 150 is preferable, 80 to 130 is more preferable, and 90 to 120 is particularly preferable.

  An example of a method for producing a polyurethane foam according to the method of the present invention is as follows. First, a predetermined amount of a polyol component for producing polyurethane foam, a foaming agent, a catalyst, a foam stabilizer, and other additives as necessary are mixed. The mixture and the organic polyisocyanate component are then rapidly mixed using a polyurethane foam foamer or stirrer. The obtained mixed liquid (foaming stock solution) can be continuously foamed to obtain a polyurethane foam. Alternatively, it can be poured into a sealed or open mold (made of metal or resin), subjected to a urethanization reaction, cured for a predetermined time, and then demolded to obtain a polyurethane foam.

  The polyurethane foam obtained by the method of the present invention is suitably used for vehicle cushions, furniture / building materials, clothing, electrical equipment, electronic equipment or packaging.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this.

<Examples 1 to 79 Production of Strength Improvement Agent>
Hereinafter, the production of the strength improvers K-1 to K-19 and the polyol compositions B-1 to B-60 will be described. The measured values of the obtained strength improvers are shown in Tables 1 and 2.

The active hydrogen-containing compound used in the production of the strength improver is described below. Those not described can be easily obtained as reagents.
GP-250: Glycerin PO adduct (Sanix GP-250 manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 250, hydroxyl value 670)
GP-1000: glycerin PO adduct (Sanyox GP-1000 manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 1000, hydroxyl value 160)
SP-750: Sucrose PO adduct (Sanix SP-750 manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 750, hydroxyl value 490)
GP-3000NS: Glycerin PO adduct (Sanix GP-3000NS manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 3000, hydroxyl value 56)
RP-410A: sucrose PO adduct (Sanix RP-410A manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 1070, hydroxyl value 420)

Polyol (I): glycerin PO adduct (number average molecular weight 500, hydroxyl value 337)
A stainless steel autoclave equipped with a stirrer and a temperature controller was charged with 1 mol of glycerin and 0.03 mol of KOH, and dehydrated at 130 ± 5 ° C. and 10 kPa for 2 hours. After completion of dehydration, the mixture was cooled to 110 ± 5 ° C., dropped over 4 hours while controlling 7 mol of PO to be 0.5 MPa or less, and aged for 2 hours after the completion of dropping. After completion of aging, the mixture was cooled to 90 ± 5 ° C., 2% by weight of water and 2% by weight of KYOWARD 600 (manufactured by Kyowa Chemical Co., Ltd .; synthetic silicate) were added and treated for 1 hour. After taking out from the autoclave, it was filtered using 1 micron filter paper and dehydrated under reduced pressure to obtain polyol (I).

Polyol (II): pentaerythritol PO adduct (number average molecular weight 550, hydroxyl value 408)
EP-400 (manufactured by Sanyo Chemical Industries, Ltd .; pentaerythritol PO adduct, number average molecular weight 400, hydroxyl value 561) was charged in 1 mol and KOH 0.03 mol in a stainless steel autoclave equipped with a stirrer and a temperature controller. It dehydrated at 130 ± 5 ° C. and 10 kPa for 2 hours. After completion of the dehydration, the mixture was cooled to 110 ± 5 ° C., dropped over 4 hours while controlling 2.6 mol of PO to be 0.5 MPa or less, and aged for 2 hours after the completion of dropping. After completion of aging, the mixture was cooled to 90 ± 5 ° C., 2% by weight of water and 2% by weight of KYOWARD 600 (manufactured by Kyowa Chemical Co., Ltd .; synthetic silicate) were added and treated for 1 hour. After taking out from the autoclave, it was filtered using 1 micron filter paper and dehydrated under reduced pressure to obtain polyol (II).

Polyol (III): pentaerythritol PO adduct (number average molecular weight 1500, hydroxyl value 149.6)
In a stainless steel autoclave equipped with a stirrer and a temperature controller, 1 mol of EP-400 manufactured by Sanyo Chemical Industries, Ltd. and 0.08 mol of KOH were charged and dehydrated at 130 ± 5 ° C. and 10 kPa for 1 hour. After completion of dehydration, the mixture was cooled to 110 ± 5 ° C., dropped over 4 hours while controlling the PO19 mole to be 0.5 MPa or less, and aged for 2 hours after the completion of dropping. After completion of aging, the mixture was cooled to 90 ± 5 ° C., 2% by weight of water and 2% by weight of KYOWARD 600 (manufactured by Kyowa Chemical Co., Ltd .; synthetic silicate) were added and treated for 1 hour. After taking out from the autoclave, it was filtered using 1 micron filter paper and dehydrated under reduced pressure to obtain polyol (III).

Polyol (IV): phthalic acid EO adduct (number average molecular weight 250, hydroxyl value 449)
1 mol of phthalic acid is charged in a stainless steel autoclave equipped with a stirrer and temperature controller, and dropped at 110 ± 5 ° C over 2 hours while controlling 2.1 mol of EO to 0.5 MPa or less. Aging for 6 hours gave polyol (IV).

Polyol (V): glycerin PO / EO block adduct (number average molecular weight 5500, hydroxyl value 30.6)
A stainless steel autoclave equipped with a stirrer and a temperature controller was charged with 1 mol of glycerin and 0.25 mol of KOH and dehydrated at 130 ± 5 ° C. and 10 kPa for 1 hour. After completion of the dehydration, the mixture was cooled to 110 ± 5 ° C., dropped over 4 hours while controlling the PO mol to be 0.5 MPa or less, and aged for 2 hours after the dropping. After aging, 19 mol of EO was added dropwise over 2 hours while controlling to 130 ° C. ± 5 ° C. and 0.5 MPa or less, and aging was performed for 2 hours after the completion of the addition. After completion of aging, the mixture was cooled to 90 ± 5 ° C., 2% by weight of water and 2% by weight of KYOWARD 600 (manufactured by Kyowa Chemical Co., Ltd .; synthetic silicate) were added and treated for 1 hour. After taking out from the autoclave, it was filtered using 1 micron filter paper and dehydrated under reduced pressure to obtain polyol (V).

The strength improvers K-1, 2, 6-10, 13-16, 18 and 19 were each prepared using the raw materials and amounts (moles) shown in Table 1 by the following production method. As an example, 1 mol of glycerin is added to the Dean-Stark reactor described in K-1 (of the molar ratio in Table 1, the number of hydroxyl groups of the active hydrogen-containing compound is the anhydride group of trimellitic anhydride used). The same number of moles), 3 mol of trimellitic anhydride, 3.6 mol of toluene as a solvent, and half esterification was performed at 80 ± 10 ° C. for 2 hours in a nitrogen atmosphere. Thereafter, 6 mol of glycerin (number of moles excluding the portion used previously in the molar ratio in Table 1) and 0.06 mol of sulfuric acid as a catalyst were added to control to 95 ± 5 ° C. and 550 ± 10 kPa. The reaction was continued for 6 hours. During the reaction, volatile toluene and water were condensed and separated with a cooler, and toluene was returned to the reactor again. After completion of the reaction, the solution was neutralized with an aqueous sodium hydroxide solution, and water and toluene were added to extract the strength improver K-1. Thereafter, toluene was distilled off at 80 ± 10 ° C. and 10 kPa to obtain a strength improver K-1. The measured values of each strength improver are shown in Table 1.

Strength improvers K-3 and 17 were each prepared using the raw materials and amounts used (in moles) shown in Table 1 by the following production method. As an example, the Dean-Stark reactor described in K-3 is 1 mol of Sanix GP-250 (manufactured by Sanyo Chemical Industries, Ltd., number average molecular weight 250, hydroxyl value 670) in the molar ratio in Table 1. The number of moles of the hydroxyl group of the hydrogen-containing compound is the same as the number of moles of pyromellitic anhydride used), 3 moles of pyromellitic anhydride, 9.8 moles of toluene as a solvent, and 80 ± 10 in a nitrogen atmosphere. Half esterification was carried out at 2 ° C. for 2 hours. Thereafter, water was added in the same mole as pyromellitic anhydride and stirred for 30 minutes. Thereafter, 9 moles of GP-250 (number of moles in Table 1 excluding the amount previously used) and 0.15 mole of sulfuric acid as a catalyst were added to 95 ± 5 ° C. and 550 ± 10 kPa. The reaction was performed for 6 hours while controlling. During the reaction, volatile toluene and water were condensed and separated with a cooler, and toluene was returned to the reactor again. After completion of the reaction, the solution was neutralized with an aqueous sodium hydroxide solution, and water and toluene were added to extract the strength improver K-3. Thereafter, toluene was distilled off at 80 ± 10 ° C. and 10 kPa to obtain a strength improver K-3. The measured values of each strength improver are shown in Table 1.

The strength improvers K-4, 5, 11 and 12 were each prepared by the following production method using the raw materials and usage amounts (moles) shown in Table 1. As an example, the Dean-Stark reactor described in K-4 is 1 mol of Sanix GP-250 (manufactured by Sanyo Chemical Industries, Ltd., number average molecular weight 250, hydroxyl value 670) in the molar ratio in Table 1. The number of moles of hydroxyl groups in the hydrogen-containing compound is the same mole as the polycarboxylic acid used), 3 moles of 2,3,6-naphthalenetricarboxylic acid, 7.9 moles of toluene as a solvent, sulfuric acid as a catalyst 0.12 mol was charged and reacted for 3 hours under nitrogen atmosphere while controlling to 95 ± 5 ° C. and 550 ± 10 kPa. During the reaction, volatile toluene and water were condensed and separated with a cooler, and toluene was returned to the reactor again. After the reaction, 6 mol of GP-250 (the number of moles excluding the portion used previously in the molar ratio in Table 1) was added, and the reaction was performed under the same conditions as the previous reaction. After the reaction, the solution was neutralized with an aqueous sodium hydroxide solution, and water and toluene were added to extract the strength improver K-4. Thereafter, toluene was distilled off at 80 ± 10 ° C. and 10 kPa to obtain a strength improver K-4. The measured values of each strength improver are shown in Table 1.

  Polyol compositions B-1 to B-60 were prepared by mixing various strength improvers (K) and various polyols (P) at 80 ± 10 ° C. for 30 minutes in a nitrogen atmosphere. Table 2 shows the mixed formulation of various strength improvers and polyols. The mixing amount wt% described in Table 2 represents the weight% of the strength improver (K) based on the weight of (B) in the polyol composition (B).

Comparative Example 1
Glycerin PO adduct (Sanix GP-3000NS; hydroxyl value 56.0, manufactured by Sanyo Chemical Industries, Ltd.) was used as the polyol (H-1). The measured values of (H-1) are as follows.
Hydroxyl value (mgKOH / g) = 56.0, amount of trivalent or higher valent aromatic polycarboxylic acid (wt%) = 0, aromatic ring concentration (mmol / g) = 0.0.

Comparative Example 2
Glycerin PO adduct (manufactured by Sanyo Chemical Industries, Ltd .; hydroxyl value 112.0) was used as polyol (H-2). The measured value of (H-2) is as follows.
Hydroxyl value (mgKOH / g) = 112.0, amount of trivalent or higher valent aromatic polycarboxylic acid (wt%) = 0, aromatic ring concentration (mmol / g) = 0.0

Comparative Example 3
In a stainless steel autoclave with a stirrer and a temperature controller, 1 mol of glycerin PO adduct (Sanyox GP-1500 manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 1500, hydroxyl value 112.0), 6 mol of phthalic anhydride and Half esterification was performed by charging 0.010 mol of an alkali catalyst (N-ethylmorpholine) and reacting at 0.20 MPa and 120 ± 10 ° C. for 1 hour in a nitrogen atmosphere. Thereafter, PO6 mol was added dropwise over 5 hours while controlling the pressure to be 120 ± 10 ° C. and a pressure of 0.50 MPa or less, followed by aging at 120 ± 10 ° C. for 1 hour. After completion of aging, the alkali catalyst was removed under reduced pressure at 0.1 MPa for 1 hour to obtain a polyol (H-3). The measured values of (H-3) are as follows.
Hydroxyl value (mgKOH / g) = 63, amount of trivalent or higher valent aromatic polycarboxylic acid (wt%) = 0, aromatic ring concentration (mmol / g) = 2.26.

Comparative Example 4
In an autoclave similar to Comparative Example 1, 1 mol of glycerin PO adduct (Sanyox GP-1500 manufactured by Sanyo Chemical Industries, Ltd .; number average molecular weight 1500, hydroxyl value 112.0), 6 mol of phthalic anhydride and an alkali catalyst (N -Ethylmorpholine) 0.010 mol was charged, and half esterification was performed by reacting at 0.20 MPa and 120 ± 10 ° C. for 1 hour in a nitrogen atmosphere. Thereafter, 20 mol of EO was added dropwise over 5 hours while controlling the pressure to be 80 ± 10 ° C. and a pressure of 0.50 MPa or less, followed by aging at 80 ± 10 ° C. for 1 hour. After completion of aging, the alkali catalyst was removed under reduced pressure at 0.1 MPa for 1 hour to obtain a polyol (H-4). The measured values of (H-4) are as follows.
Hydroxyl value (mgKOH / g) = 51.2, amount of trivalent or higher valent aromatic polycarboxylic acid (wt%) = 0, aromatic ring concentration (mmol / g) = 1.82.

Comparative Example 5
In the same autoclave as in Comparative Example 1, 1 mol of GP-3000NS and 0.22 mol of KOH were charged and dehydrated at 110 ± 5 ° C. and 10 kPa for 1 hour. After completion of dehydration, 36.2 mol of PO was added dropwise over 4 hours while controlling to 0.5 MPa or less, and aging was performed for 3 hours after completion of the addition. After completion of aging, the mixture was cooled to 90 ± 5 ° C., 2% by weight of water and 2% by weight of KYOWARD 600 (manufactured by Kyowa Chemical Co., Ltd .; synthetic silicate) were added and treated for 1 hour. After taking out from the autoclave, it was filtered using 1 micron filter paper and dehydrated under reduced pressure to obtain a polyol (H-5). The measured value of (H-5) is as follows.
Hydroxyl value (mgKOH / g) = 33.7 Amount of trivalent or higher valent aromatic polycarboxylic acid (wt%) = 0, aromatic ring concentration (mmol / g) = 0.0.

<Examples 80 to 119 and Comparative Examples 6 to 8 Production of soft slab foam>
Using the strength improver (K) and the strength improver-containing polyol composition (B), a flexible polyurethane foam was produced by foaming under the following foaming conditions according to the formulation shown in Tables 3 to 4, and Foam core density (kg / m ³ ), hardness (25% ILD, N / 314 cm ² ), tear strength (N / cm), tensile strength after standing at a temperature of 23 ° C. and a humidity of 50% for 24 hours The thickness (kPa) and elongation (%) were measured. The measured values are shown in Tables 3 to 4, respectively.

(Foaming conditions)
BOX SIZE: 250mm x 250mm x 250mm
Material: Wood Mixing method: Hand mixing (foaming method in which a necessary amount of necessary reagent is charged in a predetermined container, and then a stirring blade is inserted into the container and stirred for 6 to 20 seconds at a rotational speed of 5000 rpm)
Mixing time: 6 to 20 seconds, stirring blade rotation speed: 5000 rotations / minute

The polyurethane foam raw materials in Examples 80 to 119 and Comparative Examples 6 to 8 are as follows.
(1) Organic polyisocyanate component (D-1)
TDI: NCO% = 48.3 (trade name: Coronate T-80, manufactured by Nippon Polyurethane Industry Co., Ltd.)
(2) Blowing agent Blowing agent: Water (3) Catalyst catalyst-1: “DABCO-33LV” (33% by weight dipropylene glycol solution of triethylenediamine) manufactured by Air Products Japan Co., Ltd.
Catalyst-2: Tin octylate (trade name: “Neostan U-28” manufactured by Nitto Kasei Co., Ltd. (stannic octylate)
(4) Foam stabilizer Foam stabilizer-1: “L-540” manufactured by Toray Dow Corning

<Test method>
The measurement method for each item is as follows. The obtained results are shown in Tables 3 to 4.
-The measurement method and unit of foam physical properties are shown below.
Core density: Conforms to JIS K6400, unit is kg / m ³
Hardness (25% -ILD): Conforms to JIS K6400, unit is N / 314 cm ²
Elongation: Conforms to JIS K6400, unit is%
Tensile strength: Conforms to JIS K6400, unit is kPa
Tear strength: Conforms to JIS K6400, unit is N / cm

  In Tables 3 to 4, the polyurethane foams of Examples 80 to 119 of the present invention have foam physical properties, particularly foam hardness, tensile strength, and tear strength, compared with the polyurethane foams of Comparative Examples 6 to 8 obtained by conventional techniques. It has improved.

<Examples 120-159 and Comparative Examples 9-10 Production of flexible HR foam>
According to the foaming formulation shown in Tables 5 to 6, after forming a foam by foaming a flexible polyurethane foam in the mold under the following foaming conditions, the foam is taken out from the mold for 24 hours at a temperature of 23 ° C. and a humidity of 50%. ) Various properties of the flexible polyurethane foam after standing were measured. The measured values are shown in Tables 5 to 6, respectively.

(Foaming conditions)
Mold size: 40cm x 40cm x 10cm (height)
Mold temperature: 65 ° C
Mold material: Aluminum Mixing method: High pressure urethane foaming machine (manufactured by Polymer Engineering) Mixing polyol premix and isocyanate at 15 MPa

The raw materials of the flexible polyurethane foam in Examples 120 to 159 and Comparative Examples 9 to 10 are the same as those shown in the above Examples and Comparative Examples, and the other items are as follows.
1. Catalyst catalyst-3: “TOYOCAT ET” manufactured by Tosoh Corporation (70% by weight dipropylene glycol solution of bis (dimethylaminoethyl) ether)
2. Foam stabilizer Foam stabilizer-2: “TEGOSTAB B8737LF” manufactured by EVONIK

3. Organic polyisocyanate component (D-2)
“CE-729” manufactured by Nippon Polyurethane Industry Co., Ltd. (TDI-80 (2,4- and 2,6-TDI, ratio of 2,4-isomer is 80% / crude MDI (average functional group number: 2.9 ) = 80/20 (weight ratio))
4). Polyol (1) Polymer polyol (P-1): Polyoxyethylene polyoxy having an average number of functional groups of 3.0 obtained by block addition of PO and EO to glycerin, a hydroxyl value of 34, and a total of EO units = 14% Polymer polyol (polymer content 30%) obtained by copolymerizing styrene and acrylonitrile (weight ratio: 30/70) in propylene polyol. Hydroxyl value 24.
(2) Polyol (P-2): Polyoxyethylene polyoxypropylene polyol (average functional group number 3.0, hydroxyl value 24, total of EO units = 72% obtained by randomly adding PO and EO to glycerin ( 3) Polyol (P-3): polyoxypropylene polyol (4) polyol (P-4): glycerin having an average functional group number of 6.0 and a hydroxyl value of 490 obtained by adding PO to sorbitol. Functional group number 3.0, hydroxyl value 1829.
(5) Polyol (P-5): Polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 4.0, a hydroxyl value of 28, and a total of EO units of 14% obtained by block addition of PO and EO to pentaerythritol (6) Polyol (P-6): Polyoxyethylene polyoxypropylene polyol having an average number of functional groups of 3.0, a hydroxyl value of 33, and a total of EO units of 14% obtained by block addition of PO and EO to glycerin

The measurement method for each item is as follows. The obtained results are shown in Tables 5 and 6.
-The measurement method and unit of foam physical properties are shown below.
Core density: Conforms to JIS K6400, unit is kg / m ³
Elongation: Conforms to JIS K6400, unit is%
Tensile strength: Conforms to JIS K6400, unit is kPa
Hardness (25% -ILD): Conforms to JIS K6400, unit is N / 314 cm ²
Tear strength: Conforms to JIS K6400, unit is N / cm

表５、表６において、本発明実施例１２０〜１５９のポリウレタンフォームは、従来技術により得られる比較例９〜１０のポリウレタンフォームよりも、フォーム物性、特にフォーム硬さや引張強さ、引裂強さが向上している。

In Tables 5 and 6, the polyurethane foams of Examples 120 to 159 of the present invention have foam physical properties, particularly foam hardness, tensile strength, and tear strength, compared with the polyurethane foams of Comparative Examples 9 to 10 obtained by conventional techniques. It has improved.

<Examples 160 to 193, Comparative Examples 11 to 13>
In accordance with the foaming formulation shown in Tables 7 and 8, a rigid polyurethane foam is foamed in a mold under the following foaming conditions to form a foam, and after demolding all day and night (24 hours at a temperature of 23 ° C. and a humidity of 50%) The solid polyurethane foam was measured for various physical properties. Tables 7 and 8 also show measured values of physical properties.

(Foaming conditions)
Mold size: 40cm x 40cm x 5cm (height)
Mold temperature: 35 ℃
Mold material: Aluminum Mixing method: High pressure urethane foaming machine (manufactured by Polymer Engineering Co., Ltd.) Mixing polyol premix and isocyanate at 12 MPa

The raw materials of the rigid polyurethane foams in Examples 160 to 193 and Comparative Examples 11 to 13 are the same as those shown in the above Examples, and other items are as follows.
1. Catalyst catalyst-4: “U-CAT 1000” (amine-based catalyst) manufactured by San Apro Co., Ltd.
2. Foam stabilizer Foam stabilizer-3: “SF-2936F” manufactured by Toray Dow Corning Co., Ltd.

3. Organic polyisocyanate component (D-3)
"Millionate MR-200" (Polymeric MDI) manufactured by Nippon Polyurethane Industry Co., Ltd.
4). Polyol (1) Polyol (P-7): Polyoxypropylene polyol having an average functional group number of 8.0 obtained by adding PO to sucrose and a hydroxyl value of 490 (2) Polyol (P-8): Pentaerythritol with PO Polyoxypropylene polyol (3) Polyol (P-9) having an average functional group number of 4.0 and a hydroxyl value of 410 obtained by adding NO: Average functional group number of 6.0 and hydroxyl group obtained by adding PO to sorbitol 4. Polyoxypropylene polyol having a value of 400 Flame Retardant Flame Retardant-1: “TMCPP” manufactured by Daihachi Chemical Industry Co., Ltd. (Tris (β-chloropropyl phosphate 6. blowing agent blowing agent-1: “HFC-245fa” manufactured by Central Glass Co., Ltd.) (1 , 1,1,3,3-pentafluoropropane)

The measurement method for each item is as follows. The obtained results are shown in Tables 7 and 8.
Density: Conforms to JIS A9511, unit is kg / m ³
Compressive strength: Conforms to JIS A9511, unit is kPa

  In Tables 7 and 8, the polyurethane foams of Examples 160 to 193 of the present invention have improved foam physical properties, particularly compressive strength, as compared with the polyurethane foams of Comparative Examples 11 to 13 obtained by the prior art.

  The polyurethane foam of the present invention can be used for all kinds of polyurethane foam for vehicle seats, furniture, building materials, bedding, apparel, electrical equipment, electronic equipment, packaging, and other uses (sanitary goods, cosmetics). Can be suitably used.

Claims (7)

A strength improver having a structure in which a polycarboxylic acid and an active hydrogen-containing compound (H) having two or more active hydrogens are condensed, wherein the polycarboxylic acid contains a trivalent or higher valent aromatic carboxylic acid (A), A strength improver for producing polyurethane foam (K) having three or more structures derived from (A) in one molecule of the strength improver. The strength improver for producing polyurethane foam according to claim 1, wherein the hydroxyl value is 30 to 400 mgKOH / g. The strength improver for producing polyurethane foam according to claim 1 or 2, wherein the aromatic ring concentration is 0.1 to 10.0 mmol / g. The strength improver for producing polyurethane foam according to any one of claims 1 to 3, wherein the active hydrogen-containing compound (H) constituting the strength improver (K) is one kind. The polyol composition (B) for polyurethane foam manufacture containing the strength improvement agent (K) for polyurethane foam manufacture in any one of Claims 1-4, and a polyol (P). The polyurethane foam production according to claim 5, wherein the content of the strength improver (K) for producing polyurethane foam based on the weight of the polyol composition (B) for producing polyurethane foam is 0.1 or more and less than 100% by weight. Polyol composition. The polyurethane foam production strength improver (K) according to any one of claims 1 to 4 or the polyurethane foam production polyol composition (B) according to claim 5 or 6, an organic polyisocyanate component (D), A process for producing a polyurethane foam obtained by reacting in the presence of a foaming agent, a catalyst and a foam stabilizer.