JP6892379B2 - Polyol composition for producing flexible polyurethane foam - Google Patents

Description

The present invention relates to a polyol composition for producing flexible polyurethane foam. More specifically, the present invention relates to a polyol composition suitable for producing a flexible polyurethane foam having low resilience and good breathability.

Flexible polyurethane foam is widely used for furniture, bedding mattresses, automobile seat cushions, clothing, etc. In particular, low-resilience pillows and mattresses for bedding are preferred.
Conventionally, it has been known that low resilience can be imparted by selecting a polyol component and an isocyanate component constituting a flexible polyurethane foam and adjusting the glass transition point (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-185335

However, the low-resilience flexible polyurethane foam has insufficient breathability. Poor breathability causes heat buildup and impairs comfort. In addition, there is a risk of shrinkage during the manufacturing process.
An object to be solved by the present invention is to provide a polyol composition for producing a low-resilience flexible polyurethane foam having good breathability.

The present inventors have arrived at the present invention as a result of studies for achieving the above object.
That is, the present invention comprises a polyether polyol (A1) having a hydroxyl value of 28 mgKOH / g or more and less than 85 mgKOH / g, and a polyether polyol (A2) having a hydroxyl value of 85 mgKOH / g or more and 400 mgKOH / g or less. Production of flexible polyurethane foam which is an alkylene oxide adduct of a tetrahydric alcohol, has a hydroxyl value of 760 mgKOH / g or more, has a number average molecular weight of 260 or less, and contains an alkylene oxide adduct (B) containing an ethylene oxide. Polyurethane composition (C); a polyol composition (C) for producing a flexible polyurethane foam and an organic polyisocyanate component (D) in the presence of a catalyst (E), a foaming agent (F) and a foam stabilizer (G). It is a method for producing a flexible polyurethane foam that reacts with.

By using the polyol composition for producing a flexible polyurethane foam of the present invention, a flexible polyurethane foam having low resilience and good breathability can be produced.

The polyol composition (C) for producing a flexible polyurethane foam of the present invention contains a combination of a polyether polyol (A1) and a polyether polyol (A2) having significantly different hydroxyl values and an alkylene oxide adduct (B). The hydroxyl value of the polyether polyol (A1) is 28 mgKOH / g or more and less than 85 mgKOH / g, and the hydroxyl value of the polyether polyol (A2) is 85 mgKOH / g or more and 400 mgKOH / g or less. Further, the alkylene oxide adduct (B) is an alkylene oxide adduct of a 2- to 4-valent alcohol, the hydroxyl value thereof is 760 mgKOH / g or more, and the number average molecular weight is 260 or less.

Polyether polyols (A1) include non-alcohols having 2 to 4 valences (dihydric alcohols having 2 to 20 carbon atoms, trihydric alcohols having 3 to 20 carbon atoms, tetrahydric alcohols having 4 to 20 carbon atoms, etc.) Examples thereof include alkylene oxides (hereinafter, may be abbreviated as AO) of active hydrogen group-containing compounds such as 2- to 4-valent hydroxyl group-containing compounds, amino group-containing compounds, and thiol group-containing compounds.

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 an alicyclic type. Examples thereof include diols (cyclohexanediol, cyclohexanedimethanol, etc.).

Examples of trihydric alcohols having 3 to 20 carbon atoms include aliphatic triols (glycerin, trimethylolpropane, etc.). Examples of the tetravalent alcohol having 4 to 20 carbon atoms include an aliphatic polyol (pentaerythritol and the like).

Examples of 2- to 4-valent hydroxyl group-containing compounds other than alcohol include polyhydric phenols (hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1,3,6,8-tetrahydroxynaphthalene, 1,4,5,8. -Tetrahydroxyanthracene, etc.), polybutadiene polyol, castor oil-based polyol, condensate of phenol and formaldehyde (Novolak, etc.) and the like.

Examples of the amino group-containing compound include amines, polyamines and amino alcohols. Specifically, ammonia, alkylamines having 1 to 20 carbon atoms (butylamine, etc.), aniline, aliphatic polyamines (ethylenediamine, hexamethylenediamine, etc.), heterocyclic polyamines (piperazine, N-aminoethylpiperazine, etc.), fats Cyclic polyamines (such as dicyclohexylmethanediamine and isophoronediamine), aromatic polyamines (such as phenylenediamine, tolylenediamine and diphenylmethanediamine), alkanolamines (such as monoethanolamine, diethanolamine and triethanolamine), dicarboxylic acids and excess polyamines. Examples thereof include polyamide polyamines, polyether polyamines, hydrazines (hydrazine, monoalkyl hydrazines, etc.) and dicyandiamides obtained by condensation with.

Examples of the thiol group-containing compound include polythiol compounds. Examples of polythiols include 2- to tetravalent multi-valent thiols. Specific examples thereof include ethanedithiol and 1,6-hexanedithiol.

Examples of the phosphoric acid compound include phosphoric acid, phosphorous acid and phosphonic acid.

As AO, AO having 2 to 4 carbon atoms, for example, ethylene oxide (hereinafter, may be abbreviated as EO), 1,2-propylene oxide (hereinafter, may be abbreviated as PO), 1,3 -Propylene oxide, 1,2-butylene oxide and 1,4-butylene oxide can be mentioned.
Of these, 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, the addition form may be block addition, random addition, or a combination of these.

From the viewpoint of elastic modulus, the hydroxyl value of the polyether polyol (A1) is 28 or more and less than 85 mgKOH / g, preferably 28 to 60 mgKOH / g, and more preferably 30 to 58 mgKOH / g. The number of functional groups of the polyether polyol (A1) is preferably 2 to 4 from the viewpoint of the elastic modulus.
Two or more kinds of polyether polyols (A1) may be used in combination.

Polyether polyols (A2) are also other than alcohols having 2 to 4 valences (dihydric alcohols having 2 to 20 carbon atoms, trihydric alcohols having 3 to 20 carbon atoms, tetrahydric alcohols having 4 to 20 carbon atoms, etc.) Examples thereof include AO adducts of active hydrogen group-containing compounds such as 2- to 4-valent hydroxyl group-containing compounds, amino group-containing compounds, and thiol group-containing compounds. As this AO, the same AO as that used in the above-mentioned polyether polyol (A1) can be used, and the bonding form when two or more kinds are used in combination is the same as that of the polyether polyol (A1).

From the viewpoint of elastic modulus, the hydroxyl value of the polyether polyol (A2) is 85 or more and 400 mgKOH / g or less, preferably 110 to 400 mgKOH / g, and more preferably 150 to 350 mgKOH / g.
The number of functional groups of the polyether polyol (A2) is preferably 2 to 4 from the viewpoint of the elastic modulus.
Two or more kinds of polyether polyols (A2) may be used in combination.

The polyol composition (C) for producing a flexible polyurethane foam of the present invention imparts low resilience to a flexible polyurethane foam by combining a polyether polyol (A1) and a polyether polyol (A2) having different hydroxyl value ranges. Can be done.
Two or more kinds of polyether polyols (A1) or two or more kinds of polyether polyols (A2) may be used in combination, but one or more kinds of polyether polyols (A1) and polyether polyols (A2) must be used together. It is necessary to use one or more of them together.

The alkylene oxide adduct (B) is an alkylene oxide adduct of a 2- to tetravalent alcohol. As the AO, the same AO as that used in the above-mentioned polyether polyol (A1) can be used, and the bonding form when two or more kinds are used in combination is the same as that of the polyether polyol (A1). However, from the viewpoint of breathability, EO is always included as AO.
The EO / AO (molar ratio) is preferably 0.7 to 1.0, more preferably 1.0.

Examples of the 2-tetrahydric alcohol used for the alkylene oxide adduct (B) include aliphatic diols (ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and the like. ), Aliphatic triol (glycerin, trimethylolpropane, etc.), aliphatic tetraol (pentaerythritol, etc.).
Of these, glycerin, trimethylolpropane and pentaerythritol are preferred, with glycerin being particularly preferred.

The hydroxyl value of the alkylene oxide adduct (B) is 760 mgKOH / g or more, preferably 760 to 950 mgKOH / g, from the viewpoint of air permeability.

The number average molecular weight of the alkylene oxide adduct (B) is 260 or less, preferably 180 to 260, from the viewpoint of air permeability.

The average number of moles of alkylene oxide added to the alkylene oxide adduct (B) is preferably 2 to 4 moles.
As a specific example of the alkylene oxide adduct (B), an average of 2 to 4 mol of ethylene oxide adduct of glycerin is preferable.

The content of (B) is preferably 0.1 to 2.0% by weight based on the weight of the polyol composition (C) for producing a flexible polyurethane foam. Within this range, the air permeability is high and the elastic modulus is also low.

The flexible polyurethane foam of the present invention is a mixture containing the above-mentioned polyol composition for producing flexible polyurethane foam (C), an organic polyisocyanate component (D), a catalyst (E), a foaming agent (F) and a foam stabilizer (G). It is a flexible polyurethane foam made of the foam of.

As the organic polyisocyanate (D), all organic polyisocyanates used in flexible polyurethane foam can be used, and aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, and modified products thereof. (Urethane group, carbodiimide group, allophanate group, urea group, burette group, isocyanurate group, oxazolidone group-containing modified product, etc.) and a mixture of two or more of these can be mentioned.

As the aromatic polyisocyanate, an aromatic diisocyanate having 6 to 16 carbon atoms excluding carbon in the NCO group (in the following polyisocyanates, the carbon number in the NCO group is excluded). , Aromatic triisocyanates having 6 to 20 carbon atoms and crude products of these isocyanates can be mentioned. Specific examples include 1,3- or 1,4-phenylenediocyanate, 2,4- or 2,6-toluene diisocyanate (TDI), crude TDI, 2,4'-or 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 and lysine diisocyanate.

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

Examples of the aromatic aliphatic isocyanate include aromatic aliphatic 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 organic polyisocyanates (D), aromatic polyisocyanates are preferable from the viewpoint of reactivity and moldability, and more preferably TDI, crude TDI, MDI, crude MDI and modified products of these isocyanates, in particular. Preferably, it is TDI, MDI and crude MDI.

Polyurethane foam is obtained by reacting a polyol composition with isocyanate, and the amount of isocyanate used is adjusted by adjusting the ratio of isocyanate groups (NCO groups) to active hydrogen atoms in the raw material. Will be done.
In the flexible polyurethane foam of the present invention, the ratio of isocyanate groups (NCO groups) to active hydrogen atoms [also referred to as isocyanate index (index)] is preferably 80 to 100, more preferably 80 to 100, from the viewpoint of impact resilience and air permeability. It is 82 to 98, particularly preferably 85 to 95.
The isocyanate index (index) is calculated as the ratio (%) of the equivalent of the isocyanate group in (D) to the equivalent of the active hydrogen atom-containing group in the polyol composition (C) for producing a flexible polyurethane foam.

From the viewpoint of moldability, the amount of the catalyst (E) used is preferably 0.01 to 5.0 parts by weight, more preferably 0.02 to 2.0 parts by weight, based on 100 parts by weight of the polyol composition (C). It is a part by weight. The catalyst (E) may be used alone or in combination of two or more.

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

Examples of the low boiling point compound include hydrogen atom-containing halogenated hydrocarbons and low boiling point hydrocarbons. Specific examples of hydrogen atom-containing halogenated hydrocarbons and low-boiling hydrocarbons include methylene chloride, HCFCs (hydrochlorofluorocarbons) (HCFC-123, HCFC-141b, HCFC-142b, etc.); HFCs (hydrofluorocarbons) (HFC- 152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc, etc.), butane, pentane, cyclopentane and the like.

Of 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.

The amount of water used as the foaming agent (F) is preferably 1.0 to 4.0 parts by weight, more preferably 1.2, based on 100 parts by weight of the polyol composition (C) from the viewpoint of foam density. ~ 3.8 parts by weight.
From the viewpoint of moldability, the amount of the low boiling point compound used as the foaming agent (F) is preferably 30 parts by weight or less, more preferably 5 to 25 parts by weight, based on 100 parts by weight of the polyol composition (C). is there.
The amount of liquefied carbon dioxide gas as the foaming agent (F) is preferably 30 parts by weight or less, more preferably 1 to 25 parts by weight, based on 100 parts by weight of the polyol composition (C).

As the defoaming agent (G), known defoaming agents (silicone-based defoaming agents, non-silicone-based defoaming agents, etc.) used for producing polyurethane foam can be used, and are manufactured by Toray Dow Corning Co., Ltd. "SZ-1959", "SF-2904", "SZ-1142", "SZ-1720", "SZ-1675t", "SF-2936F", "SZ-3601", "SRX-294A", "SH" -193 "," L-540 "," L-3601 "manufactured by Nippon Unicar Co., Ltd.," L-626 "manufactured by Momentive Performance Materials," B8715 LF2 "manufactured by Ebonic Degusa Japan Co., Ltd. , Etc., which can be obtained from the market.
From the viewpoint of moldability and impact resilience, the amount of the defoaming agent (G) used is preferably 0.4 to 5.0 parts by weight, more preferably 0. 4 to 3.0 parts by weight.

The flexible polyurethane foam of the present invention may be a foam that has undergone a urethanization reaction using other auxiliaries described below.
Other auxiliaries include colorants (dye and pigment), plasticizers (phthalates and adipates, etc.), organic fillers (synthetic short fibers, hollow microspheres made of thermoplastic or thermosetting resin, etc.). , Known auxiliary components such as flame retardant (phosphate ester, halogenated phosphoric acid ester, etc.), antiaging agent (triazole, benzophenone, etc.) and antioxidant (hindered phenol, hindered amine, etc.).

The amount of these auxiliaries added is preferably 1 part by weight or less with respect to 100 parts by weight of the polyol composition (C). 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, more preferably 2 to 20 parts by weight. The antiaging 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 the auxiliary agent used is preferably 50 parts by weight or less, more preferably 0.2 to 30 parts by weight.

The flexible polyurethane foam according to the method of the present invention can be produced by a known method. For example, first, a predetermined amount of the polyol composition (C) for producing a flexible polyurethane foam, a foaming agent, a catalyst, a foam stabilizer, and if necessary, other additives are mixed. The mixture is then rapidly mixed with the organic polyisocyanate component using a polyurethane foam foamer or stirrer. A flexible polyurethane foam can be obtained by continuously foaming the obtained mixed solution (foaming stock solution). Further, it can be injected into a closed type or open type mold (made of metal or resin), subjected to a urethanization reaction, cured for a predetermined time, and then demolded to obtain a flexible polyurethane foam.

The elastic modulus of the flexible polyurethane foam of the present invention is preferably 15% or less from the viewpoint of sitting comfort and sleeping comfort.

The breathability of the flexible polyurethane foam of the present invention ^{is preferably 10 cc / cm 2} / sec or more from the viewpoint of sitting comfort and sleeping comfort.

The flexible polyurethane foam of the present invention is used for furniture, bedding pillows, bedding mattresses, automobile seat cushions, clothing and the like.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified,% indicates a weight% and a part indicates a weight part.

Production Example 1 <Production of Polyether Polyol (A1-1)>
The reaction temperature was set to 95 ° C to 130 ° C using potassium hydroxide as a catalyst [catalyst usage 0.3% by weight (reaction product weight standard)] so that the molar ratio of glycerin to PO was 1: 58.9. After adding PO to glycerin, potassium hydroxide was removed using Kyoward 600 [manufactured by Kyowa Chemical Industry Co., Ltd.] to obtain a polyether polyol (A1-1). (A1-1) is a PO adduct of glycerin having a hydroxyl value of 48 and a Mn of 3,500.

Production Example 2 <Production of Polyether Polyol (A1-2)>
A PO / EO mixture containing PO and EO was added to glycerin at a ratio of 16.6 mol of PO and 51.0 mol of EO to 1 mol of glycerin, and the hydroxyl value was 51 by the same operation as in Production Example 1. A polyether polyol (A1-2), which is a PO / EO random adduct of glycerin having a Mn of 3300, was obtained.

Production Example 3 <Production of Polyether Polyol (A2-1)>
5.9 mol of PO was added to 1 mol of propylene glycol, and by the same operation as in Production Example 1, a polyether polyol (A2-1) which is a PO adduct of propylene glycol having a hydroxyl value of 270 and a Mn of 420. ) Was obtained.

Production Example 4 <Production of Polyether Polyol (A2-2)>
11.7 mol of PO was added to 1 mol of glycerin, and by the same operation as in Production Example 1, a polyether polyol (A2-2), which is a PO adduct of glycerin having a hydroxyl value of 220 and a Mn of 770, was added. Obtained.

Production Example 5 <Production of alkylene oxide adduct (B-1)>
2.5 mol of EO was added to 1 mol of glycerin, and by the same operation as in Production Example 1, an alkylene oxide adduct (B-1) which is an EO adduct of glycerin having a hydroxyl value of 840 and a Mn of 200 was added. Got

Production Example 6 <Production of alkylene oxide adduct (B-2)>
2.5 mol of EO was added to 1 mol of pentaerythritol, and by the same operation as in Production Example 1, an alkylene oxide adduct (B-) which is an EO adduct of pentaerythritol having a hydroxyl value of 910 and a Mn of 245 was added. 2) was obtained.

Comparative Production Example 1 <Production of alkylene oxide adduct (B'-1)>
10 mol of EO was added to 1 mol of glycerin, and by the same operation as in Production Example 1, an alkylene oxide adduct (B') which is an EO adduct of glycerin having a hydroxyl value of 315 and a Mn of 530 was used in Comparative Example. -1) was obtained.

Comparative Production Example 2 <Production of alkylene oxide adduct (B'-2)>
An alkylene oxide adduct which is a PO adduct of glycerin having a hydroxyl value of 710 and a Mn of 235, which is used in Comparative Example by adding 2.5 mol of PO to 1 mol of glycerin and performing the same operation as in Production Example 1 ( B'-2) was obtained.

Comparative Production Example 3 <Production of alkylene oxide adduct (B'-3)>
2.5 mol of EO is added to 1 mol of sorbitol, and by the same operation as in Production Example 1, an alkylene oxide adduct (alkylene oxide adduct) which is an EO adduct of sorbitol having a hydroxyl value of 1150 and a Mn of 290 is used in Comparative Example. B'-3) was obtained.

<Examples 1 and 2, Comparative Examples 1 and 6>
Each of the polyol components shown in Table 1 was uniformly mixed in a mixing container to obtain a polyol composition (C) for producing a flexible polyurethane foam according to Examples 1 and 2 and Comparative Examples 1 to 6.

Further, the polyol compositions (C-1) to (C-2) obtained in Examples 1 and 2 and the polyol compositions (C'-1) to (C'-) obtained in Comparative Examples 1 to 6 Using 6), the organic isocyanates, catalysts, foaming agents, and foam stabilizers shown in Table 1 are further added and uniformly mixed, and foamed under the following foaming conditions to form flexible polyurethane foams (H-1) to (H-2). ) And (H'-1) to (H'-6) were prepared.
Of the numerical values of each component in Table 1, the numerical values excluding the organic polyisocyanate (D-1) are the number of parts by weight, and the organic polyisocyanate (D-1) is the isocyanate index. An amount of organic isocyanate corresponding to the isocyanate index was used.

<foaming conditions>
Mold size: 250 mm x 250 mm x 250 mm
Material: Wood mixing method:
Hand mixing (a foaming method in which the required amount of the required reagent is charged in a predetermined container, and then the stirring blade is inserted into the container and stirred at a rotation speed of 5000 rpm for 6 to 20 seconds).
Mixing time: 6 to 20 seconds Stirring blade rotation speed: 5000 rotations / minute

The following organic isocyanates, catalysts, foaming agents, and foam stabilizers shown in Table 1 were used.
Organic polyisocyanate (D-1): Mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (mixing ratio: 80/20) [Product name: "Coronate T-80" manufactured by Toso Co., Ltd. (isocyanate group) Content = 48.3% by weight)]
Catalyst (E-1): "DABCO-33LX" manufactured by Air Products Japan Co., Ltd.
Catalyst (E-2): "DABCO-BL22" manufactured by Air Products Japan Co., Ltd.
Catalyst (E-3): "Neostan U-28" manufactured by Nitto Kasei Co., Ltd.
Foaming agent (F): Water defoaming agent (G-1): Silicone defoaming agent "SF-2904" manufactured by Toray Dow Corning Co., Ltd.

The obtained flexible polyurethane foam was allowed to stand at a temperature of 25 ° C. and a humidity of 50% for 24 hours, and then the density, air permeability and elastic modulus of each flexible polyurethane foam were measured based on the following measurement methods, and the results were obtained. It is shown in Table 1.

<Test method for flexible polyurethane foam>
The measurement method for each item is as follows.
(1) Density: Measured according to JIS K6400 (unit: kg / m ³ ).
(2) Breathability: Measured according to JIS K6400 (unit: cc / cm ² / sec).
(3) Elastic modulus: Measured according to JIS K6400 (unit:%).

Since the polyol compositions of Examples 1 and 2 of the present invention contain an appropriate amount of the alkylene oxide adduct (B), the obtained flexible polyurethane foam has a low elastic modulus and high air permeability.
On the other hand, Comparative Example 1 which does not contain the alkylene oxide adduct (B), Comparative Example 2 which uses the alkylene oxide adduct (B'-1) having a high molecular weight, and the alkylene oxide adduct (B'-) which does not contain EO. The air permeability of Comparative Example 3 using 2) and Comparative Example 4 using the alkylene oxide adduct (B'-3) of hexahydric alcohol is low.
Further, Comparative Example 5 containing no polyether polyol (A2) had a high rebound resilience, and Comparative Example 6 containing no polyether polyol (A1) shrank during standing after foaming.

The flexible polyurethane foam obtained by using the polyol composition of the present invention has excellent low resilience and breathability, and therefore can be suitably used as a seat cushion, bedding and furniture.

Claims (2)

Average of a polyether polyol (A1) having a hydroxyl value of 28 mgKOH / g or more and less than 85 mgKOH / g, a polyether polyol (A2) having a hydroxyl value of 150 mgKOH / g or more and 350 mgKOH / g or less, and ethylene oxide of glycerin. the number average molecular weight in 2-4 molar adduct is a by hydroxyl value 760mgKOH / g or higher 260 or less der Ru alkylene oxide adduct (B) and a flexible polyurethane foam production for polyol composition containing (C) met A polyol composition for producing a flexible polyurethane foam, wherein the content of (B) is 0.1 to 2.0% by weight based on the weight of the polyol composition (C). The polyol composition (C) for producing a flexible polyurethane foam according to claim 1 and the organic polyisocyanate component (D) are reacted in the presence of a catalyst (E), a foaming agent (F) and a foam stabilizer (G). A method for producing a flexible polyurethane foam to be used, wherein the amount of (D) used is such that the ratio of isocyanate groups to active hydrogen atoms in the raw material is 82 to 98.