JP5274996B2 - Method for producing flexible polyurethane foam - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing a flexible polyurethane foam, and more particularly to a method for producing a flexible polyurethane foam suitable for uses such as a cushion for a vehicle seat, the obtained flexible polyurethane foam, and a vehicle seat cushion material. It is.

  Conventionally, flexible polyurethane foams have been widely used in cushion materials for automobiles and the like, taking advantage of their excellent cushioning properties. In particular, the method of obtaining flexible polyurethane foam using diphenylmethane diisocyanate and polymethylene polyphenylene polyisocyanate as the main component of isocyanate improves the working environment by reducing productivity and reducing the use of highly toxic tolylene diisocyanate. In recent years, it has attracted a great deal of attention. As a method for producing a cushion comprising this flexible polyurethane foam, a polyol component containing a specific polyol and a polymer polyol, and a polyisocyanate component mainly composed of diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and / or a modified product thereof, and There is known a manufacturing method using the above. (For example, refer patent document 1) The flexible polyurethane foam manufactured by this method has the characteristics that it is low density and moldability is good.

JP 7-206961 A

  In recent years, a cushion material having low density and excellent ride comfort has been demanded for use as a backrest of a vehicle seat. However, the above manufacturing method has a problem that even if the density is low, the impact resilience is low and the riding comfort is not sufficient.

  The inventors of the present invention, after intensive studies to solve these problems, combine a polyol component having a specific content ratio and a specific isocyanate to produce a flexible polyurethane foam having a low density and a high resilience as a cushioning material. Thus, the present invention has been completed.

That is, the present invention uses the following polyol component (A), polyisocyanate component (B), foaming agent (C), catalyst (D) and foam stabilizer (E) as essential raw materials. the method of manufacturing; the flexible polyurethane foam obtained by the process; and soft crystalline poly urethane vehicle comprised of foam seat cushion material; a.
Polyol (A):
It contains a polyol (a) having 2 to 8 functional groups and a polymer polyol (b), and the polyol (a) comprises a polyether polyol (a1) having 3 functional groups and a polyether polyol (a2) having 4 functional groups. Each of (a1) and (a2) has a hydroxyl value of 20 to 40 mgKOH / g, oxyethylene is added to the terminal, and the content of the terminal oxyethylene unit is 5 to 25 wt. The polymer polyol (b) is a polymer polyol obtained by polymerizing the vinyl monomer (v) in the same polyether polyol as the above (a1) and / or the above (a2), and a polyol component It contained (a), the Ri weight ratio [(a1) / (a2)] is (70/30) - (90/10) der of used (a1) and (a2), polio Weight ratio of Lumpur (a) and the polymer polyol (b) is (a) / (b) = (60/40) ~ (90/10) Ru der.
Polyisocyanate component (B):
50% by weight or more of the polyisocyanate component is one or more polyisocyanates selected from diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and modified products thereof, and less than 50% by weight is tolylene diisocyanate.

  According to the method for producing a flexible polyurethane foam of the present invention, it is possible to obtain a flexible polyurethane foam having a low density and high rebound resilience as compared with the conventional method.

  Among the polyol components (A) in the present invention, the polyol (a) having 2 to 8 functional groups is, for example, an alkylene of an active hydrogen atom-containing compound such as a divalent to octavalent alcohol, a phenol or an amine. An oxide adduct is mentioned, and the valence of the active hydrogen atom-containing compound used is the same as that of the resulting polyol.

  Examples of the alcohols include dihydric alcohols having 2 to 18 carbon atoms [ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,3-butylene. Glycol, diethylene glycol, neopentyl glycol, etc.], C3-C18 trivalent alcohols [glycerin, trimethylolpropane, pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylit, mannitol, glucose, Fructose, sucrose, etc.] and combinations of two or more thereof. Examples of the phenols include hydroquinone, bisphenols (bisphenol A, bisphenol F, etc.), phenolic formalin low condensates (number average molecular weight 1000 or less) (novolak resin, intermediate of resole), and two or more of these Can be used in combination.

  Examples of the amines include ammonia; alkanolamines [monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, aminoethylethanolamine, etc.]; alkylamines having 1 to 20 carbon atoms [methylamine, ethylamine, n -Butylamine, octylamine and the like]; alkylene diamines having 2 to 6 carbon atoms [ethylene diamine, hexamethylene diamine and the like]; polyalkylene polyamines having an alkylene group having 2 to 6 carbon atoms (degree of polymerization 2 to 8) [diethylenetriamine, Triethylenetetramine, etc.]; C6-C20 aromatic amines [aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diphenyl ether diamine, etc.]; C4-C15 alicyclic Amines [isophoronediamine, cyclohexylenediamine, etc.]; heterocyclic amines having 4 to 15 carbon atoms [aminoethylpiperazine, those described in Japanese Patent Publication No. 55-21044], and combinations of two or more thereof. Can be mentioned.

  Examples of the alkylene oxide in the alkylene oxide adduct include alkylene oxides having 2 to 6 carbon atoms, such as ethylene oxide, 1,2-propylene oxide, 1,3-propylene oxide, and 1,4-butylene oxide. Of these, 1,2-propylene oxide (hereinafter abbreviated as PO) and ethylene oxide (hereinafter abbreviated as EO) are preferable. The addition method of PO and EO may be block addition, random addition, or a combination thereof.

  The polyol (a) having 2 to 8 functional groups in the present invention usually contains a polyether polyol (a1) having 3 functional groups and a polyether polyol (a2) having 4 functional groups, and (a1) and (a2) are All of them must satisfy the following requirements.

(1) having a hydroxyl value of 20 to 40 mgKOH / g, preferably 25 to 40 mgKOH / g; if the hydroxyl value of (a1) and (a2) is less than 20 mgKOH / g, the compression set is poor and the curing time is long. Therefore, the practicality is poor, and when it exceeds 40 mgKOH / g, the number of closed cells increases, so the practicality is poor. The adjustment of the hydroxyl value can be adjusted by the number of functional groups, the type of alkylene oxide and the number of added moles.

(2) An oxyethylene group is always added to the terminal, and the content of the terminal oxyethylene unit is 5 to 25% by weight, preferably 8 to 20% by weight based on the weight of (a1) or (a2). When the content of the terminal oxyethylene unit is less than 5% by weight, the foam is not easily cured immediately before the end of foaming and the foam tends to collapse. When the content of the terminal oxyethylene unit exceeds 25% by weight, there are many closed cells. It becomes easy to shrink the foam.

(3) The polymer polyol (b) is a polymer polyol obtained by polymerizing the vinyl monomer (v) in the same polyether polyol as the above (a1) and / or the above (a2), and the polyol component (A The weight ratio [(a1) / (a2)] used in (a1) and (a2) is (60/40) to (90/10), preferably (70/30) to (80 / 20); When (a1) is less than 60, the number of closed cells increases, and the physical properties of the foam deteriorate. When (a1) exceeds 90, the compression set deteriorates, and the curing time also increases. Since it becomes longer, it becomes less practical.

  The polyol (a) can contain other polyols other than the above (a1) and (a2). Examples of other polyols include the following polyol (a3) and the following polyol (a4).

  Polyol (a3): The average number of functional groups is 2 to 8, preferably 2 to 6, the hydroxyl value is 300 to 2000 mgKOH / g, preferably 400 to 1900 mgKOH / g, and the active hydrogen atom-containing compound has 2 carbon atoms. And / or a polyol obtained by adding 3 alkylene oxides.

Among the polyols (a3), from the viewpoint of reactivity, a PO single addition or an EO single addition product (polyoxypropylene polyol or polyoxyethylene polyol) is preferable. When the average number of functional groups of the polyol (a3) is 2 or more, the compression set is further improved and the curing time is shortened, which is more practical. When the average functional group is 8 or less, the foam elongation property is further improved. When the hydroxyl value is 300 mgKOH / g or more, the foam hardness can be sufficiently exerted, and when it is 2000 mgKOH / g or less, the foam elongation property is further improved.
Examples of the polyol (a3) include polyoxyethylene polyol having a hydroxyl value of 842 mgKOH / g, triethanolamine having a hydroxyl value of 1130 mgKOH / g, and the like.

  Polyol (a4): The average number of functional groups is 2-6, preferably 2-4, the hydroxyl value is 20-130 mgKOH / g, preferably 22-120 mgKOH / g, and the carbon number of the oxyalkylene group is 2 and / or Or a polyether polyol having a content of oxyethylene units of 50 to 80% by weight, preferably 60 to 80% by weight. Among the polyols (a4), preferred is an EO / PO random adduct having an oxyethylene unit content of 50 to 80% by weight from the viewpoint of foam breathability.

  When the average functional group number of the polyol (a4) is 2 or more, the curing time is shortened, which is more practical. When the polyol (a4) is 6 or less, the foam elongation property is further improved. If the content of oxyethylene units is 50% by weight or more, the number of closed cells in the foam is further reduced and the foam tends to be difficult to shrink. If the hydroxyl value is 20 mgKOH / g or more, the hardness of the foam tends to be more sufficient, and if it is 130 mgKOH / g or less, the foam has fewer closed cells and the foam tends to be difficult to shrink.

  In the present invention, the polyol (a) uses the polyols (a1) and (a2) as essential polyols, and further contains the polyols (a3) and (a4), the total weight of the polyol (a) Based on the above, it is preferable that the total of (a1) and (a2) is 88 to 98.5% by weight, (a3) is 1 to 8% by weight, and (a4) is 0.5 to 4% by weight. More preferably, the sum of (a1) and (a2) is 89 to 97.5% by weight, (a3) is 2 to 8% by weight, and (a4) is 0.5 to 3% by weight. If (a3) is 1% by weight or more, the hardness of the foam is further improved, and if it is 8% by weight or less, the elongation property is easily improved. If (a4) is 0.5% by weight or more, closed cells tend to be further reduced, and if it is 4% by weight or less, the curing time tends to be further shortened. If the total of (a1) and (a2) is 88% by weight or more, the stretched physical properties of the foam tend to be exhibited more satisfactorily. There is a tendency.

  The polymer polyol (b) of the polyol component (A) in the present invention is a vinyl monomer (v) in the same polyether polyol as the above (a1) and / or (a2). It is a polymer polyol obtained by polymerization by a method. The polyol used for the production of the polymer polyol is preferably (a1) from the viewpoint of moldability. The polymerization is obtained by polymerizing and stably dispersing the vinyl monomer (v) in the presence of a normal radical initiator. Examples of the vinyl monomer (v) include acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl (2 to 5 carbon atoms) (meth) acrylate, and alkyl (1 to 5 carbon atoms) (meth) acrylate. Preferred are acrylonitrile and styrene.

  In the present invention, the content of the vinyl polymer in the polymer polyol (b) is preferably 1 to 40% by weight. If it is 1% by weight or more, the hardness of the foam can be exhibited sufficiently, and if it is 40% by weight or less, compression set can be exhibited more satisfactorily.

  In the polyol component (A) in the present invention, the weight ratio of the polyol (a) and the polymer polyol (b) is preferably (a) / (b) = 50/50 to 95/5 from the viewpoint of foam hardness. More preferably, (a) / (b) = 60/40 to 90/10.

  As the polyisocyanate component (B) in the present invention, one or more polyisocyanates selected from diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and modified products thereof for reasons such as improvement of productivity and improvement of work environment ( (Hereinafter abbreviated as MDI)) is 50% by weight or more, preferably 60 to 90% by weight. Examples of the modified products include urethane-modified products, carbodiimide-modified products, allophanate-modified products, urea-modified products, burette-modified products, isocyanurate-modified products, and oxazolidone-modified products. The content of other polyisocyanates is 50% by weight or less, preferably 10 to 40% by weight, and is tolylene diisocyanate.

  As the foaming agent (C) in the present invention, water is essential. In addition, hydrogen atom-containing halogenated hydrocarbons, low boiling point hydrocarbons, liquefied carbon dioxide gas, or the like may be used, and one or more other types may be used in combination with water. In the case of using only water alone as (C), the amount of water used is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, especially 100 parts by weight of the polyol component (A). Preferably it is 2-6 weight part. The amount of water used when used in combination with another blowing agent is preferably 0.1 to 10 parts by weight, more preferably 2 to 6 parts by weight, based on the weight of the polyol component (A).

  Examples of the hydrogen atom-containing halogenated hydrocarbon include those of the HCFC (hydrochlorofluorocarbon) type (for example, HCFC-123, HCFC-141b, HCFC-22, and HCFC-142b); those of the HFC (hydrofluorocarbon) type (for example, HFC- 134a, HFC-152a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, and HFC-365mfc). Among these, HCFC-141b, HFC-134a, HFC-356mff, HFC-236ea, HFC-245ca, HFC-245fa, HFC-365mfc and a mixture of two or more thereof are preferred. The amount of hydrogen atom-containing halogenated hydrocarbon used is preferably 50 parts by weight or less, more preferably 5 to 45 parts by weight per 100 parts by weight of the polyether component (A).

  The low boiling point hydrocarbon is usually a hydrocarbon having a boiling point of −5 to 50 ° C., and specific examples thereof include butane, pentane, cyclopentane, and mixtures thereof. The amount of low-boiling hydrocarbon used is preferably 40 parts by weight or less, more preferably 5 to 30 parts by weight per 100 parts by weight of the polyether component (A). The amount of liquefied carbon dioxide used is preferably 30 parts by weight or less, more preferably 25 parts by weight or less per 100 parts by weight of the polyether component (A).

  As the catalyst (D) in the present invention, a usual catalyst for promoting the urethanization reaction can be used. Examples thereof include triethylenediamine, bis (N, N-dimethylamino-2-ethyl) ether, N, N, N ′. , N′-tetramethylhexamethylenediamine and other tertiary amines and carboxylic acid salts thereof; carboxylic acid metal salts such as potassium acetate, potassium octylate and stannous octoate; and organometallic compounds such as dibutyltin dilaurate. The amount of the catalyst (D) used is preferably 0.01 to 5 parts by weight, more preferably 0.2 to 2 parts by weight with respect to 100 parts by weight of the polyether component (A).

  As the foam stabilizer (E) in the production method of the present invention, those used in the production of ordinary polyurethane foams can be used. As an example, a dimethylsiloxane foam stabilizer [for example, “Toray Dow Corning Co., Ltd.” SRX-253 "etc.], polyether-modified dimethylsiloxane foam stabilizers (for example," L-3640 "manufactured by Momentive Performance Materials LLC," SF-2962 "manufactured by Toray Dow Corning Co., Ltd.) Examples thereof include silicone foam stabilizers such as “SZ-1327” and “TEGOSTAB B8715LF” manufactured by Goldschmidt. The amount of the foam stabilizer (E) used is preferably 0.5 to 3 parts by weight, more preferably 0.8 to 2.0 parts by weight with respect to 100 parts by weight of the polyether component (A).

  In the production method of the present invention, if necessary, other additives as described below may be used and reacted in the presence thereof. For example, colorants (dyes, pigments), flame retardants (phosphate esters, halogenated phosphate esters, etc.), anti-aging agents (triazoles, benzophenones, etc.), antioxidants (hindered phenols, hindered amines) Etc.) in the presence of the usual auxiliary components. Regarding the usage-amount of these auxiliary components with respect to 100 weight part of polyol components (A), a coloring agent becomes like this. Preferably it is 1 weight part or less. The flame retardant is preferably 5 parts by weight or less, more preferably 2 parts by weight or less. The anti-aging agent is preferably 1 part by weight or less, more preferably 0.5 part by weight or less. The antioxidant is preferably 1 part by weight or less, more preferably 0.01 to 0.5 part by weight.

  In the production method of the present invention, an isocyanate index [(NCO group / active hydrogen atom-containing group equivalent ratio) × 100] (hereinafter referred to as an index) in the production of polyurethane is preferably 70 to 125, more preferably 75. ˜120, particularly preferably 80˜115.

  The flexible polyurethane foam of the present invention can be obtained by an ordinary method for producing a flexible urethane foam using the above raw materials as essential raw materials. An example of the manufacturing method is as follows. First, a predetermined amount of a polyol component (A), a foaming agent (C), a catalyst (D), a foam stabilizer (E), and, if necessary, other additives are mixed. Subsequently, this mixture and polyisocyanate component (B) are temperature-controlled at 25 degreeC using a polyurethane foaming machine (for example, "High pressure foaming machine" made by PEC) or a stirrer, and then rapidly mixed. The obtained mixed liquid (foaming stock solution) is poured into a sealed or open mold (made of metal or resin) adjusted to 65 ° C. to perform a urethanization reaction, demolded after curing for a predetermined time. A flexible polyurethane foam can be obtained. In addition, a flexible polyurethane foam can be obtained even by continuous foaming. The present invention is particularly suitable as a method for producing a mold foam.

The flexible polyurethane foam of the present invention preferably has a total density of 28 to 50 kg / m ³ , more preferably 33 to 45 kg / m ² , preferably a rebound resilience of 60 to 75%, more preferably 63 to 75%. It is. When the total density is 28 kg / m ³ or more, the wet heat compressive stress strain is further improved, and when it is 50 kg / m ³ or less, the foam breathability is further improved. When the impact resilience is 60% or more, the ride comfort is further improved. The total density and impact resilience can be measured based on the method of JIS K 6401 relating to the measurement of physical properties of polyurethane foam.

  The vehicle seat cushion material composed of the flexible polyurethane foam of the present invention can be obtained by a normal method for producing a vehicle seat cushion material using the above-mentioned raw materials as essential raw materials. An example of the manufacturing method is as follows. First, a predetermined amount of a polyol component (A), a foaming agent (C), a catalyst (D), a foam stabilizer (E), and, if necessary, other additives are mixed. Subsequently, this mixture and polyisocyanate component (B) are temperature-controlled at 25 degreeC using a polyurethane foaming machine (for example, "High pressure foaming machine" made by PEC) or a stirrer, and then rapidly mixed. The obtained mixed solution (foaming stock solution) is poured into a sealed or open mold (made of metal or resin) for vehicle seats adjusted to 65 ° C. to allow urethanization reaction, and after curing for a predetermined time By removing the mold, a flexible polyurethane foam for a vehicle seat cushion material can be obtained. Moreover, even if it foams continuously, the flexible polyurethane foam for vehicle seat cushion materials can be obtained. The present invention is particularly suitable as a method for producing a mold foam. The vehicular seat cushion material composed of the flexible urethane foam of the present invention has a high impact resilience and has a characteristic that it is comfortable to ride as a vehicular seat.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by this. In Examples and Comparative Examples, “parts” and “%” respectively represent “parts by weight” and “% by weight” unless otherwise specified.

The raw materials in the examples and comparative examples are as follows. (Hereinafter, the EO unit means an oxyethylene unit.)
<Raw material as polyol (a1)>
Polyol (a1-1): 85.4 mol of PO added to glycerin, and then 21.9 mol of EO, functional group number 3, hydroxyl value 28 mgKOH / g, terminal EO unit 16%,
Polyol (a1-2): 72.5 mol of PO added to glycerin and then 15.9 mol of EO, functional group number 3, hydroxyl value 34 mgKOH / g, terminal EO unit 14%,
<Raw material as polyol (a2)>
Polyol (a2-1): 101.4 mol of PO added to pentaerythritol, followed by 19.1 mol of EO, number of functional groups 4, hydroxyl value 32.1 mg KOH / g, terminal EO unit 12%,
<Raw material as polymer polyol (b)>
Polymer polyol (b-1): Polymer polyol obtained by polymerizing acrylonitrile at 130 ° C. in polyol (a1-2), hydroxyl value 28 mgKOH / g (polymer content 20% by weight).
Polymer polyol (b-2): a polymer polyol obtained by copolymerizing acrylonitrile and styrene in polyol (a1-2) / (a2-1) = 80/20 with acrylonitrile / styrene = 70/30, hydroxyl value 26.7 mg KOH / g (polymer content 40% by weight).
<Raw material as polyol (a3)>
Polyol (a3-1): a polyoxyethylene polyol having 6 functional groups, a hydroxyl value of 1246 mgKOH / g, and an EO unit content of 55%.
Polyol (a3-2): A polyoxyethylene polyol having 3 functional groups and a hydroxyl value of 842 mgKOH / g.
Polyol (a3-3): Triethanolamine having 3 functional groups and a hydroxyl value of 1130 mgKOH / g.
<Raw material as polyol (a4)>
Polyol (a4-1): Random addition polyoxyethylene polyoxypropylene polyol having 3 functional groups, a hydroxyl value of 24 mgKOH / g, and an EO unit content of 70%.
<Other raw materials>
Foaming agent (C): Water catalyst (D-1): Ethylene glycol solution of triethylenediamine [“TEDA-L33” manufactured by Tosoh Corporation]
Catalyst (D-2): 70% dipropylene glycol solution of bis (dimethylaminoethyl) ether [“TOYOCAT ET” manufactured by Tosoh Corporation]
Foam stabilizer (E-1): “TEGOSTAB B8715LF” manufactured by Goldschmidt
Foam stabilizer (E-2): “L-3640” manufactured by Momentive Performance Materials GK
Isocyanate (B-1): TDI-80 / crude MDI = 35/65 (weight ratio), NCO% = 35.6
Isocyanate (B-2): TDI-80 / crude MDI = 20/80 (weight ratio), NCO% = 32.0

Examples 1-7 and Comparative Examples 1-5
Using a high-pressure foaming machine (manufactured by PEC), the polyol component and the polyisocyanate component shown in Tables 1 and 2 were adjusted to 25 ° C., then impact-mixed and 400 × 400 × 100 mm adjusted to 65 ° C. Poured into a closed mold and molded with a cure time of 6 minutes. Tables 1 and 2 show the measurement results of the physical properties of each form. The physical properties of the polyurethane foam were measured based on the method of JIS K 6401. In Tables 1 and 2, “parts” represents “parts by weight”.

  From the above results, when compared with foams having the same density, the foams of Examples 1 to 7 obtained by the method of the present invention are soft polyurethane foams having higher impact resilience than the foams of Comparative Examples 1 to 5. Can be obtained.

  According to the method for producing a flexible polyurethane foam of the present invention, a flexible polyurethane foam having a low density and high impact resilience and excellent ride comfort when used in a vehicle seat cushion material as compared with the conventional method. Can be obtained.

Claims (6)

The manufacturing method of the flexible polyurethane foam characterized by using the following polyol component (A), the following polyisocyanate component (B), a foaming agent (C), a catalyst (D), and a foam stabilizer (E) as an essential raw material.
Polyol component (A):
It contains a polyol (a) having 2 to 8 functional groups and a polymer polyol (b), and the polyol (a) comprises a polyether polyol (a1) having 3 functional groups and a polyether polyol (a2) having 4 functional groups. Each of (a1) and (a2) has a hydroxyl value of 20 to 40 mgKOH / g, oxyethylene is added to the terminal, and the content of the terminal oxyethylene unit is 5 to 25 wt. The polymer polyol (b) is a polymer polyol obtained by polymerizing the vinyl monomer (v) in the same polyether polyol as the above (a1) and / or the above (a2), and a polyol component It contained (a), the Ri weight ratio [(a1) / (a2)] is (70/30) - (90/10) der of used (a1) and (a2), polio Weight ratio of Lumpur (a) and the polymer polyol (b) is (a) / (b) = (60/40) ~ (90/10) Ru der.
Polyisocyanate component (B):
50% by weight or more of the polyisocyanate component is one or more polyisocyanates selected from diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate and modified products thereof, and less than 50% by weight is tolylene diisocyanate. The polyol component (a) further contains the following polyol (a3) and polyol (a4), and the total weight of polyol (a1) and polyol (a2) is 88 to 98 based on the total weight of polyol (a). 2. The method for producing a flexible polyurethane foam according to claim 1, wherein 0.5% by weight, the following polyol (a3) is 1 to 8% by weight, and the following polyol (a4) is 0.5 to 4% by weight.
Polyol (a3):
A polyol having an average number of functional groups of 2 to 8, a hydroxyl value of 300 to 2000 mgKOH / g, and an alkylene oxide having 2 and / or 3 carbon atoms added to an active hydrogen atom-containing compound.
Polyol (a4):
The number of average functional groups is 2 to 6, the hydroxyl value is 20 to 130 mgKOH / g, the carbon number of the oxyalkylene group is 2 and / or 3, and the content of oxyethylene units is 50 to 80% by weight. Polyether polyol.   The method for producing a flexible polyurethane foam according to claim 1 or 2, wherein the polymer content of the vinyl monomer (v) is 1 to 40% by weight based on the weight of the polymer polyol (b).   The flexible polyurethane foam obtained by the manufacturing method in any one of Claims 1-3. The flexible polyurethane foam according to claim 4, wherein the total density is 28 to 50 kg / m ³ and the impact resilience is 60 to 75%.   The vehicle seat cushion material comprised from the flexible polyurethane foam of Claim 4 or 5.