JPH02247208A - Production of polymer polyol and polyurethane - Google Patents

Abstract

PURPOSE:To obtain the title polyol which gives polyurethane of high hardness and elasticity by radical polymerization of specific polyether-ester-polyol bearing allyl groups followed by grafting monomers onto a mixture thereof with polyether polyol. CONSTITUTION:A polyether polyol is allowed to react with allyl glycidyl ether and a saturated dicarboxylic anhydride, then with an alkylene oxide to give an allyl groups-containing polyether-ester polyol. Then, the polyol is polymerized with a peroxide radical catalyst to give a high-molecular-weight polyether polyol. Another polyether polyol is added to the product, so that the concentration of the product becomes 1 to 40wt.%, then an ethylenically unsaturated group-containing monomer is grafted using a radical catalyst to give the subject polymer polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the production of polymer polyols and methods of producing polyurethanes using the same.

More specifically, allyl glycidyl ether and saturated dicarboxylic anhydride are added to polyether polyol, and allyl group-containing polyether ester polyol obtained by further reacting with alkylene oxide is polymerized with a peroxide radical catalyst to obtain a high molecular weight product. This article relates to a method for producing a polymer polyol obtained by making a polyether ester polyol, mixing it into a polyether polyol, and polymerizing an ethylenically unsaturated group-containing monomer therein, and a method for producing a polyurethane using the same. be.

[Conventional technology]

Compounds and mixtures obtained by polymerizing ethylenically unsaturated group-containing monomers in polyether polyols or polyester polyols are called polymer polyols, and are used as raw materials for polyurethane foams, polyurethane elastomers, and the like.

Conventionally, polymer polyols have poor dispersion stability and high viscosity, but polyurethanes made using them have excellent physical properties and are therefore widely used in the production of polyurethanes.

In the production of highly practical polymer polyols, acrylonitrile alone or a combination of acrylonitrile and a monomer containing ethylenically unsaturated groups such as styrene is used as the ethylenically unsaturated group-containing monomer (high acrylonitrile ratio). The polymer concentration of the polymer polyol obtained by polymerization was about 241% at most.

Polyurethane foams and polyurethane elastomers using these polymer polyols have the characteristic that the resulting polyurethane products can easily have high hardness or elastic modulus because the polymer particles in the polymer polyol act as organic fillers. show.

In addition, in the production of polymer polyols, acrylonitrile alone or a mixture of acrylonitrile/styrene with a high acrylonitrile ratio is used as the ethylenically unsaturated group-containing monomer, but the resulting polymer polyols are yellow or pale. It is yellow in color, and the polyurethane foam produced from it is also colored pale yellow and has the drawback of not being a white foam.

However, recently, there has been a demand for a white foam with high hardness, and there has been a demand for the production of even higher quality polymer polyols.

In order to achieve these objectives, it has become necessary to further increase the polymer concentration in the polymer polyol and to use an acrylonitrile/styrene mixed monomer with a high styrene ratio.

However, when the polymer concentration is increased (more than 30% by weight), a rapid increase in viscosity occurs, and when acrylonitrile and styrene are combined as monomers, when the proportion of styrene increases, the affinity with polyols decreases. As a result, dispersion stability was extremely reduced, causing aggregation and separation.

For this reason, the polymer concentration is high < (30% or more) and
It has been very difficult to obtain a polymer polyol with low viscosity and good dispersion stability under conditions with a high styrene content.

As a method to solve these problems, for example, a method of manufacturing a polymer polyol by polymerizing an ethylenically unsaturated group-containing monomer in a polyol having a polymer unsaturated group has been proposed. 51-37
228, and is described in the Public Register of Special Publication No. 51-40915.

The unsaturated polyols prepared by the methods described in these publications are
It is produced by a method in which a saturated polyol is reacted with an unsaturated polycarboxylic acid such as maleic anhydride, or by a method in which alkylene oxide is added after the reaction.

However, in the method of using unsaturated acids, the unsaturated groups of the unsaturated carboxylic acids used undergo polymerization or addition reactions, and the concentration of unsaturated groups is not constant. Therefore, when producing polymer polyols, , the copolymerization with the unsaturated group-containing monomer becomes uniform, making it difficult to produce stably.

(Problems to be Solved by the Invention) The present inventors have conducted extensive research to find a method for producing a polymer polyol that solves the above problems. As a result, under conditions of a high polymer concentration and a high styrene ratio, The present invention was achieved by discovering a method for producing a polymer polyol with low viscosity and good dispersion stability.

That is, when producing a polymer polyol, in order to stably disperse polymer particles, an ethylenically unsaturated group-containing monomer is copolymerized with a polyol containing a polymer unsaturated group in advance to generate a graft product.
It is based on a completely new idea that it can be made into a stable dispersion and solve the above problems.
This is a method in which a so-called emulsifier is synthesized in advance and a portion of this emulsifier is added to a polyether polyol in order to stably disperse polyol particles.

Since this emulsifier basically does not contain polymerizable unsaturated groups, it does not participate in copolymerization with ethylenically unsaturated group-containing monomers during the polymer polyol production reaction, resulting in products with stable properties at all times. It has the characteristic of being

Another feature is that an allyl glycidyl ether group polymer is used as an emulsifier component that has an affinity for polymer particles, and as an emulsifier component that has an affinity for a dispersion medium.
Since the same/or other polyether polyols are used,
The structure of the emulsifier can be freely designed in accordance with the polymer composition to be stabilized or the polyether polyol composition as a dispersion medium, and the stabilization of the polymer polyol is easy.

Furthermore, by introducing an ester skeleton into the emulsifier using a saturated dicarboxylic anhydride, a polymer polyol with high layer hardness can be produced.

It has been found that the polyurethane foam obtained using the above polymer polyol is whiter and harder than polyurethane foam using known polymer polyols.

[Means for Solving the Problems] That is, the present invention graft-polymerizes a part of a polyether polyol with an ethylenically unsaturated group-containing monomer,
In a method for producing a polymer polyol, (1) an allyl group-containing polyether ester polyol obtained by reacting polyether polyol (A) with allyl glycidyl ether and a saturated dicarboxylic anhydride, and then reacting with an alkylene oxide; (2) a first stage reaction step in which a high molecular weight polyether polyol (B) is obtained by polymerization using a peroxide radical catalyst; (2) a liquid high molecular weight polyether polyol (B) obtained in the first stage reaction step; ), the concentration of B is 1 to 40% by weight
A second reaction step of adding polyether polyol (C) at a ratio of This invention relates to a method for producing polyol.

The polyether polyol (A) of the present invention is one or two polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, diglycerin, trimethylolpropane, pentaerythritol, shishitang, and sorbitol.
A polyether polyol obtained by reacting one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc. with a molecular weight of 3000 to 7000, preferably 4
A value in the range of 000 to 6000 is used.

The amount of allyl glycidyl ether used in the present invention is 0.5 to 5 mol, preferably 1 to 2 mol, per 1 mol of polyether polyol (A).

When the amount of allyl glycidyl ether used is 0.5 mol or less, when graft polymerization is carried out using a radical catalyst,
Sufficient high-molecular polyether ester polyol cannot be obtained to stably disperse polymer particles.In addition, if the amount exceeds 5 moles, a rapid grafting reaction will occur even if a small amount of nodical catalyst is used, resulting in high viscosity or immobilization. This makes it difficult to control the viscosity (molecular weight) of high molecular weight polyetherester polyols.

Examples of the saturated carboxylic anhydride used in the present invention include succinic anhydride, phthalic anhydride, and glutaric anhydride. The amount of saturated dicarboxylic anhydride used is 0.5 to 5 mol per 1 mol of polyether polyol (A),
Preferably it is 1 to 2 mol.

If the amount of saturated dicarboxylic acid anhydride used is less than 0.5 mol, a polymer polyol with sufficient curing cannot be obtained, and if it is more than 5 mol, the viscosity of the produced polymer polyol will increase significantly, and at the same time, the high molecular weight polyol will not be obtained. Since the viscosity of the ether ester polyol itself increases, the neutralization reaction during neutralization and purification becomes insufficient, and at the same time, filtration failure or clogging occurs during dehydration filtration.

When polyether polyol (A) is reacted with allyl glycidyl ether and saturated dicarboxylic acid anhydride, and then with alkylene oxide to obtain an allyl group-containing polyether ester polyol, a catalyst is used to accelerate the reaction. It is preferable to do so.

Specific examples of catalysts include hydroxides, oxides, and salts of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, and lithium chloride.

The reaction temperature is 80-160°C, preferably 110-13
It is carried out at 0° C. and the polyether ester polyol obtained is purified by conventional methods.

Next, to the allyl group-containing polyether ester polyol,
A high molecular weight polyether ester polyol is produced using a peroxide radical catalyst.

Peroxide-based radical catalysts include benzoyl peroxide, propionyl peroxide, t-butylpitropaloxide, dicumyl peroxide,
Di-L-butyl peroxide and the like are used.

The amount of catalyst is 0.01 to 5.0% by weight, preferably 0.05 to 1.0% by weight, based on the allyl group-containing polyether polyol.
It is 0% by weight.

The temperature of the polymerization reaction varies depending on the type of catalyst, but is higher than the decomposition temperature, preferably 70 to 200"C1, preferably 120 to 187"C.
It is °C.

In the present invention, when producing a polymer polyol under conditions where the polymer concentration is high (20 to 60% by weight) and the styrene ratio is high, the allyl group-containing polyether ester polyol is polymerized with a peroxide radical catalyst. It is characterized in that the obtained high molecular weight polyether ester polyol is used as a dispersion stabilizer for a polymer. That is, a high molecular weight polyether ester polyol is dissolved as a dispersion stabilizer in a polyether polyol (C), and an ethylenically unsaturated group-containing monomer is polymerized in the polyether polyol (C) using a radical catalyst, thereby achieving low viscosity and dispersion stability. Obtain a good polymer polyol.

The amount of the high molecular weight polyether ester polyol added as a dispersion stabilizer is 1 to 1% by weight, preferably 5 to 20% by weight, based on the polyether polyol (C). If the amount added is less than 1% by weight, the dispersion stability of the polymer polyol will be extremely reduced, causing aggregation, separation, etc. Also,
When 40% by weight or more is added, the dispersion stability is good, but the viscosity increases significantly, making it impractical to use as a raw material for polyurethane.

Polyether polyol (C) includes ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, diglycerin, trimethylolpropane, pentaerythritol, sig sugar,
A polyether polyol obtained by reacting one or more polyhydric alcohols such as sorbitol with one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and having a molecular weight of 2000 to 6000, preferably 300
A value in the range of 0 to 5000 is used.

Ethylenically unsaturated group-containing monomers include butadiene, 1,4-pentadiene, styrene, methylstyrene,
Examples include phenylstyrene, chlorostyrene, acrylic acid, methyl methacrylate, methacrylic anhydride, acrylonitrile, methacrylatrile, phenyl acrylate, acrylamide, and vinyl acetate. Preferably, acrylonitrile alone, styrene alone, or a combination of acrylonitrile and styrene are used.

The polymerization ratio of acrylonitrile/styrene is 10010
~0/100, preferably 50150~10/90. The amount of monomer used is 20 to 60% by weight, preferably 30 to 5% by weight based on the total amount of polyether polyol and monomers.
It is 0% by weight.

As the radical catalyst, a well-known catalyst for vinyl polymerization reaction is used in an amount of 0.01 to 5% by weight, preferably 0.1 to 2.0% by weight.
added. Examples of radical catalysts include hydrogen peroxide,
benzoyl peroxide, acetyl peroxide,
peroxides such as -butyl hydroperoxide, di-t-butyl peroxide, azo compounds such as azobisisobutyronitrile, or persulfates, persuccinic acid, di-isopropyl peroxy dicarbonate and preferably azobisisobutyronitrile.

The polymerization reaction of the polymer polyol according to the invention can be carried out either batchwise or continuously.

The polymerization temperature varies depending on the type of radical catalyst, but is higher than the decomposition temperature, preferably 60 to 200" C1, preferably 90 to 160
℃ range.

The polymer polyol obtained after the completion of the polymerization reaction can be used as a raw material for polyurethane as it is, but it is preferable to use it as a raw material for polyurethane after removing unreacted monomers, decomposition products of the radical catalyst, etc. under reduced pressure after the completion of the reaction. .

The polyisocyanate used in the present invention is, for example, 2.4
-) Lylene diisocyanate, 2.6-lylene diisocyanate, a mixture of both these isocyanates in an 80/20 weight ratio (80/20- T DI ) or a 65/35 weight ratio (65/35- T DI ), crude Tolylene diisocyanate (crude TDI'), 4.4'
-diphenylmethane diisocyanate (4,4'-MD
I), 2.4'-diphenylmethane diisocyanate (2,4-MD I), 2.2'-diphenylmethane diisocyanate (2,4'-MD I), isomer mixture of diphenylmethane diisocyanate (MD
I), polymethylene polyphenylisocyanate (crude MDI) toluidine diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and carbodiimide modified products, billet modified products, dimers, trimers of these isocyanates , a prepolymer.

Polyisocyanates can be used alone or in combination, but
A polyisocyanate particularly suitable for the present invention is a mixture of a carbodiimide modification of an isomer mixture of diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate.

The crosslinking agents used in the present invention include monomeric polyols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol, 1,3-&hy-1,4-butanediol, and triethanol. amines, alkanolamines such as jetanolamine, aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, methylene orthochloroaniline, 4
．． 4'-diphenylmethanediamine, aniline, 2゜4
-tolylene diamine, 2.6-) It is a compound having a hydroxyl value of 20011 gKOH/g or more obtained by adding ethylene oxide, propylene oxide, etc. to aromatic polyamines such as lylene diamine, and their active hydrogen compounds.

In addition, compounds having a hydroxyl value of 200 ■KOH/g or more obtained by adding ethylene oxide and/or propylene oxide to hydroquinone, resorcinol, aniline, etc. can also be used.

The equivalent ratio of the NCO group in the polyisocyanate to the active hydrogen in the polyol and crosslinking agent (NCO/H"J is 0.70
The polyisocyanate, polyol, and crosslinking agent are used so that the

Catalysts that can be used in combination in the present invention are conventionally known catalysts and are not particularly limited. For example, as amine-based urethanation catalysts, triethylamine, tripropylamine, triisopropanolamine, tributylamine, hexadecyldimethylamine, N - Methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, jetanolamine, triethanolamine,
N-methyljetanolamine, N,N-dimethylethanolamine, diethylenetriamine, N,N.

N', N'-tetramethylethylenediamine, N, N,
N'.

N'-tetramethylpropylene diamine, N, N, N'
.

N-tetramethylbutanediamine, N, N, N'
, N”tetramethyl-1,3-butanediamine, N
, N, N'N'-tetramethylhexamethylenediamine, bis(2-(N,N-dimethylamino)ethyl]
Ether, N, N-dimethylbenzylamine, N, N-
Dimethylcyclohexylamine, +1. N, N', N"
, N”-pentamethyldiethylenetriamine, triethylenediamine, formates and other salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, azacyclic compounds such as N,N-dialkylpiperazines, Various N,N',N''-trialkylaminoalkylhexahydrotriazines, Japanese Patent Publication No. 52-435
17 β-Aminocarbonyl Catalyst, Japanese Patent Publication No. 142-1983
79 β-aminonitrile catalyst, etc., and organometallic urethanation catalysts such as tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octoate, These include lead naphthenate, nickel naphthenate, cobalt naphthenate, etc. These catalysts may be used alone or in combination, and the amount used is from 0.0001 to 10.0 parts per 100 parts of the compound having active hydrogen.

The blowing agent in the present invention is one or more of water, trichloromonofluoromethane (Fil), dichlorodifluoromethane, methylene chloride, trichlorotrifluoroethane, dibromotetrafluoroethane, trichloroethane, pentane, n-hexane, etc. It is a mixture.

The foam stabilizer in the present invention is a conventionally known organosilicon surfactant, such as L-52 manufactured by Nippon Unicar Co., Ltd.
0, L-532, L-540%L-544, L-55
0, L-3500, L-5305, L-3600, L-
3601, L-5305, L-5307, L-5309
, L-5710, L-5720, L-5740M,
L-6202, etc., and 5H manufactured by Toray Silicone Co., Ltd.
-190,5H-192,5H-194,5H-200
,5RX-253,5RX274CSS F-2961
, SF-2962, S RX-28OA.

S RX-294A, etc., manufactured by Shin-Etsu Silicone Co., Ltd.
F-114, F-121, F-122, F-220, F
-230, F-258, F-260B, F-317
, F-341, F-601, F-606, X-20-
200, X-20-201, etc.; those manufactured by Toshiba Silicone Co., Ltd. are TFA-4200, TFA-4202, etc., and those manufactured by Goldschmidt Co., Ltd. are B-4113, etc.

The amount of these foam stabilizers used is 0.1 to 100 parts by weight of the total amount of the active hydrogen compound and polyisocyanate.
5 parts by weight.

In addition to the above, stabilizers, fillers, colorants, etc. may be used in the present invention as necessary.

To carry out the present invention, a resin component is prepared by mixing a polyol, a crosslinking agent, a foam stabilizer, a catalyst, a blowing agent, and other auxiliary agents in predetermined amounts. Further, the polyisocyanate is mixed to form a polyisocyanate component.

According to the method of the present invention, a polymer polyol having a high styrene ratio and a high polymer concentration can be produced with low viscosity and with good stability.

Furthermore, polyurethane foam produced using this as a raw material not only has high hardness and can withstand high loads, but also has a white foam, which improves product value.

(Examples) Hereinafter, in order to explain the present invention more specifically, Examples and Comparative Examples will be given and explained, but the present invention is not limited to these Examples.

Examples 1 to 5 Predetermined amounts of polyol A and caustic potash were charged into a container equipped with a thermometer and a stirring device, and the temperature was raised to 120°C.

After reaching the temperature, predetermined amounts of allyl glycidyl ether and saturated dicarboxylic anhydride were charged, and then a predetermined amount of ethylene oxide was continuously charged, followed by stirring at the same temperature for 4 hours.

After that, the temperature was lowered to 8o''C, phosphoric acid and water were added in the specified amounts, and the mixture was stirred for 30 minutes to neutralize it.After neutralization, the specified amount of adsorbent was added, and the water was heated at 2 Off + 11 Hg for 4 hours. After that, a filter aid was added and the mixture was filtered to obtain an allyl group-containing polyether ester polyol.

A predetermined amount of this allyl group-containing polyether ester polyol and a radical initiator were charged into a container equipped with a thermometer and a stirring device, and the temperature was raised to a predetermined temperature.

After reaching the temperature, stir at the same temperature for a specified time, then stir for 2 hours.
m) A vacuum treatment with Ig was performed for 30 minutes to remove decomposition products of the initiator to obtain a high molecular weight polyether ester polyol.

Table 1 shows the results of Examples (1 to 5).

Comparative Example 1 As a comparative example, a high molecular weight polyether polyol was obtained under the same reaction conditions without adding saturated dicarboxylic anhydride and ethylene oxide.

Table 1 shows the results of Comparative Example 1.

Examples 6 to 10 and Comparative Examples 2 to 3 Polyol B A predetermined amount of polyol B was filled into a pressure-resistant container equipped with a thermometer and a stirring device, and the inside of the container was purged with nitrogen several times.

While stirring, the internal temperature was raised to 100°C, and after reaching the temperature, a mixture of predetermined amounts of polyol B, the high molecular weight polyether ester polyol (dispersion stabilizer) obtained in Reference Example 1, styrene, acrylonitrile, and AIBN was added. , was continuously fed by a pump over a period of 4 hours.

After further stirring at the same temperature for 30 minutes, 2011 mHg
The mixture was treated under reduced pressure for 3 hours to obtain a white emulsion-like polymer polyol with good dispersion stability.

Table 2 shows the results of Examples (6 to 10), Comparative Examples 2 and 3.

Examples of forming the present invention are shown below.

The following raw materials were used in the examples. Hereinafter, parts refer to parts by weight.

Polyol D: A polymer polyol with a hydroxyl value of 45 ■ KOI (/g) obtained by polymerizing acrylonitrile/styrene in a polyethyl polyol obtained by addition polymerizing propylene oxide to glycerin Polyol E: Addition polymerizing propylene oxide and ethylene oxide to glycerin Polymer polyol L-6202 with a hydroxyl value of 45 KOH/g obtained by polymerizing acrylonitrile/styrene in a polyether polyol obtained by
Foaming agent S, O, Stanus octoate TDI-80/20; Toluene diisocyanate (2.4-isomer of 80χ and 2.6-isomer of 20%) TEDA i) Liethylenediamine N-MM
; N-Methylmorpholine Examples 11 to 15, Comparative Example 4
~5 180 parts of polyol B, 420 parts of the polyol of Examples 6 to 10 in Table 2 or the polyol of Comparative Example 2, L-620
24, 8 parts, H, 016, 2 parts, TEDAo, 36 parts,
20 parts of N-MMl were mixed in advance, and to this, 2 parts of SOl
After adding 0 parts and mixing at high speed, immediately add the specified TDI-80/
20 (shown in Table 3), mixed at high speed, poured into a box with internal dimensions of 300 x 300 x 150 + n, and left for 1 day and night.

The physical properties of the obtained foam were as shown in Table 3. In this example, the equivalent ratio of isocyanate groups to active hydrogen (
NGO/H) is 1.10.

In comparison with Comparative Example 4.5, the hardness was improved in all Examples.

Example 16.17 and Comparative Example 6.7 186 parts of the polyol of Examples 6 and 9 in Table 2 or the polyol of Comparative Example 2, 8434 parts of polyol, L-5740
8.7 parts of M, 24.8 parts of water, 0.50 parts of TEDA catalyst, and 1.24 parts of N-MM catalyst were mixed in advance, and to this, SO
Add 74 parts of
Add I-80/20 (shown in Table 4) and mix at high speed.Inner size 400 x 400 adjusted to 40°C in advance
Pour into a 10 ha mold, close the lid and let it foam.

After hardening in a 180'c oven for 12 minutes, the foam is removed from the mold.

The physical properties of the obtained foam are shown in Table 4. In this example, the equivalent ratio of incyanate group to active hydrogen (
NCO/H) is 1.00.

Comparative Example 6 and Comparative Example 7 using 186 parts of polyol E
The hardness was improved in all of the examples.

〔Effect of the invention〕

As shown in the Examples, the polyurethane foam produced using the polymer polyol obtained in the present invention has a higher hardness than that shown in the Comparative Examples, as shown in Tables 3 and 4. It is clear from this.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. A method for producing a polymer polyol by graft polymerizing a part of a polyether polyol with a monomer containing an ethylenically unsaturated group, in which (1) allyl glycidyl ether and The first step is to polymerize the allyl group-containing polyether ester polyol obtained by reacting a saturated dicarboxylic anhydride and then reacting an alkylene oxide using a peroxide radical catalyst to obtain a high molecular weight polyether polyol (B). a one-stage reaction step; (2) the high molecular weight polyether polyol (B) obtained in the first-stage reaction step has a B concentration of 1 to 40% by weight;
A second reaction step of adding a polyether polyol (C) at a ratio of 1 to 2 and then graft polymerizing the monomer (D) containing an ethylenically unsaturated group using a radical catalyst. manufacturing method. 2. Polyether polyol (A) has a molecular weight of 3000
7,000. The method for producing a polymer polyol according to claim 1. 3. The method for producing a polymer polyol according to claim 1, wherein the ethylenically unsaturated group-containing monomer (D) is a mixture of acrylonitrile and styrene. 4. Polyether polyol (C) has a molecular weight of 2000
6,000. The method for producing a polymer polyol according to claim 1. 5. The method for producing a polymer polyol according to claim 1, wherein the total amount of the ethylenically unsaturated group-containing monomer (D) is 20 to 60% by weight in the polymer polyol. 6. A method for producing polyurethane, which comprises producing polyurethane by reacting the polymer polyol produced by the method according to claim 1 with polyisocyanate.