JPH0673149A - Polyurethane composition using a dispersant for dispersion polymerization in non-aqueous medium - Google Patents

Abstract

PURPOSE:To obtain polyurethane coatings, adhesives and moldings of excellent physical properties without bleeding of the dispersant. CONSTITUTION:The objective composition comprises a dispersant obtained from a polyol having unsaturated bonds and an ethylenically unsaturated monomer of 6 or more carbon atoms, a polyisocyanate, a polyol and a chain extender.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyurethane composition for obtaining a polyurethane powder polymer by a non-aqueous dispersion polymerization method.

[0002]

Process for the preparation of polyurethane powder by the Background of the non-aqueous dispersion polymerization method, already, Matsumoto et al. (Journal of the Adhesion Society of Japan, 9.18
3. 1973) explains the basic polymerization method. Further, Japanese Patent Publication No. 57-29485 discloses a method for producing a polyurethane powder by a non-aqueous dispersion (emulsion) polymerization method. The most important point of this polymerization method is the choice of dispersant. Japanese Examined Japanese Patent Publication 57-29485
In the publication, a copolymer of a monomer having a long chain alkyl such as lauryl methacrylate and a monomer such as methyl methacrylate and acrylamide is used as a dispersant. This dispersant has a low dispersibility and may be insufficiently dispersed depending on the composition of the polyurethane. In addition, since the conventional dispersant is an addition type, a molded article of the polyurethane polymer may be exuded by the dispersant with the passage of time to cause problems such as appearance change.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present inventor has conducted extensive studies and studies on the dispersant composition in order to improve the dispersibility, which is a drawback of conventional dispersants, and as a result, one of the raw materials for polyurethane is A certain polyol has an unsaturated bond,
By finding a dispersant obtained by graft-polymerizing an ethylenically unsaturated monomer having a hydrocarbon side chain and using the dispersant in producing a polyurethane powder polymer by a non-aqueous dispersion polymerization method, the dispersion can be obtained. The inventors have found that the properties can be improved and completed the present invention.

[0004]

That is, according to the present invention, 100 parts by weight of a polyol having an unsaturated bond in the molecule and an ethylenically unsaturated monomer 20 having a side chain composed of a hydrocarbon group having 6 or more carbon atoms are used. The present invention relates to a polyutalene composition characterized by comprising a polyisocyanate, a polyol, and a chain extender, which are obtained by reacting ˜400 parts by weight.

The dispersant of the present invention can be effectively used for the production of polyurethane by non-aqueous dispersion polymerization of any composition. Further, the polyurethane molded product obtained by the non-aqueous dispersion polymerization does not show a change with time due to the bleeding of the dispersant because the dispersant reacts with the polyisocyanate.

As the polyol having an unsaturated bond in the molecule which can be used in the present invention, for example, in the case of polyester polyol, a glycol containing a raw material, a dibasic acid or the like having an unsaturated group-containing glycol or an unsaturated group is used. Examples thereof include those produced using a group-containing dicarboxylic acid. Further, in the case of polyether polyol, those produced by using an unsaturated group-containing glycol as a starting material are also included. Further, a polyol obtained by esterification of a hydroxyl group-terminated polyester, polyether, polycarbonate or the like having a molecular weight of 2000 or less with an unsaturated group-containing dicarboxylic acid can also be mentioned. Examples of the unsaturated group-containing glycol described here include 2-butene-1,
4-diol, glycerin monoallyl ether, etc. are mentioned. Examples of unsaturated group-containing dicarboxylic acids include maleic acid and itaconic acid. The molecular weight and unsaturated bond concentration of the polyol having an unsaturated bond in the molecule that can be used in the present invention are not particularly limited,
Desirably, the unsaturated group has a molecular weight of 3000 or less and an unsaturated bond concentration of 10 mol or less on average per one molecule of polyol. The method for producing the polyol having an unsaturated bond in the molecule of the present invention can be carried out by an ordinary method for producing polyester, polyether and the like.

Examples of the ethylenically unsaturated monomer having a side chain composed of a hydrocarbon group having 6 or more carbon atoms, which is used for producing the dispersant in the present invention, include 1-octene and 1
-Or 2-nonene, 1- or 2-decene, 1- or 2-heptadecene, 2-methyl-1-nonene, 2-methyl-1-decene, 2-methyl-1-dodecene, 2-methyl-1- Hexadecene, vinyl such as 2-methyl-1-heptadecene, aliphatic straight chain unsaturated hydrocarbon containing propenyl or isopropenyl group, acrylic acid or methacrylic acid and fats having 6 or more carbon atoms such as 2-ethylhexyl alcohol and hexyl alcohol Examples thereof include group alcohols and esters with cycloaliphatic alcohols having 6 or more carbon atoms such as cyclohexanol, norbonanol and adamantanol. These may be used alone or in combination of two or more.

The reaction between the polyol having an unsaturated bond and the ethylenically unsaturated monomer in the present invention is not particularly limited, and a usual method for polymerizing an ethylenic monomer using a radical initiator or the like as a reaction initiator. Is available. In the reaction of the present invention, a solvent can be used if necessary. For example, butyl acetate, cyclohexane, n-heptane, and other solvents commonly used for the polymerization of ethylenic monomers can be used. Furthermore, the amount ratio of the polyol having an unsaturated bond to the ethylenically unsaturated monomer of the present invention is 1
00 / 20-400 (weight) is desirable. Polyol 1
When the amount of the ethylenically unsaturated monomer is less than 20 parts by weight with respect to 00 parts by weight, the performance as a dispersant is deteriorated, and when the polyurethane is produced, it is necessary to increase the amount of the dispersant charged, which is economical. Will be at a disadvantage. When the amount of the ethylenically unsaturated monomer exceeds 400 parts by weight with respect to 100 parts by weight of the polyol, the polar and nonpolar balance is lost during the non-aqueous dispersion polymerization, and the effect as the dispersant cannot be exhibited.

The dispersant for non-aqueous dispersion polymerization of the present invention can be used as a dispersant when producing polyurethane resin by the non-aqueous dispersion polymerization method. As this polyurethane, a usual thermoplastic plastic resin, An incomplete thermoplastic polyurethane resin containing an isocyanate group or a blocked isocyanate group as necessary, a thermosetting polyurethane resin, or the like.

Polyurethanes are basically composed of polyols, chain extenders and polyisocyanates. The polyol constituting these polyurethanes includes all compounds having at least two active hydrogen groups. Examples include polyester polyols, polyalkylene ether polyols, polycarbonate polyols and mixtures thereof.

As the chain extender constituting the polyurethane, one having at least two active hydrogen groups per molecule and having a molecular weight of about 60 to about 300 can be used.

As the polyisocyanate constituting the polyurethane, a compound having at least two isocyanate groups can be used. Examples of these include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate and 4,4'-diphenylmethane diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocineate and 1,12-dodecane diisocyanate, Examples thereof include alicyclic diisocyanates such as cyclohexane 1,4-diisocyanate and isophorone diisocyanate. In addition, isocyanate group terminal compounds by the reaction of these compounds with an active hydrogen group-containing compound, carbodiimidization reaction, isocyanate modified products such as isocyanurate reaction, phosgenated polycondensation products of aniline and formartehide, etc. Other examples include isocyanate. In addition, polyisocyanate partially or wholly stabilized with a suitable blocking agent having one active hydrogen in the molecule such as methanol, n-butanol, benzyl alcohol, ε-caprolactam, methyl ethyl ketone oxime, phenol and cresol is used. You can also do it.

The content of the polyol, the chain extender and the polyisocyanate for producing polyurethane is as follows.
Although it cannot be limited because it depends on the purpose of use of the polyurethane, the molar ratio of the chain extender to the polyol is usually 1/10 to 1
The range of 0/1 is preferable, and a chain extender may not be used in some cases. Further, the molar ratio of the isocyanate group of the polyisocyanate to the polyol and the active hydrogen group of the chain extender is usually preferably in the range of 1.5 to 0.8. Since the dispersant of the present invention used for producing these polyurethanes has an active hydrogen group, the polyisocyanate compounding amount needs to be adjusted depending on the amount of the dispersant used. The content of the dispersant is usually 1 to 20% by weight based on polyurethane.

The basic technique of the non-aqueous dispersion polymerization method is disclosed in JP-B-44-30736, and its application to polyurethane is disclosed in JP-B-57-29485. In summary, the non-aqueous dispersion polymerization method is a method in which an organic liquid other than water is used as a solvent to polymerize a monomer, and an organic medium is used as a continuous phase to produce a polymer in the form of discontinuous particles. In this case, a technique of adding a dispersant to produce a polymer in a stable state is used, and the selection of the dispersant is extremely important.

The organic medium used in the non-aqueous dispersion polymerization method of the present invention is insoluble in the resulting particulate polymer and has an inert property that does not inhibit the polymerization reaction. In the present invention, for example, n-hexane, octane,
Aliphatic hydrocarbons such as dodecane and liquid paraffin, or alicyclic hydrocarbons such as cyclohexane are used.
Considering the reaction temperature, the boiling point is preferably 60 ° C or higher. These can be used alone or as a mixture of two or more kinds. Also, if necessary, toluene, butyl acetate,
A polar solvent such as methyl ethyl ketone can also be used in combination.

In the present invention, the amount ratio of the organic medium as the continuous phase and the polyurethane as the dispersed phase is preferably in the range of 10 to 80% by weight of the total amount of polyurethane. From the viewpoint of production efficiency and cost, 40% by weight or more is particularly preferable.
It is desirable to use a catalyst to increase the reaction rate of polyurene and to complete the reaction. Examples of catalysts include dibutyltin dilaurate, stannous octoate, tertiary amines such as N-methylmorpholine and triethylamine, lead naphthenate, lead octoate and the like. These catalysts are used in an amount necessary to provide a catalytic action, but usually 0.01
It is preferably about 1% by weight.

In order to disperse the reactant composed of the dispersant, the polyol, the chain extender and the polyisocyanate in the present invention in the organic medium, any known emulsification equipment may be used. As for the charging method, all the raw materials may be charged at the same time, or they may be charged stepwise according to the purpose. As a stepwise charging method, (1) an organic medium is added to a mixture of a dispersant, a polyol, and a chain extender, and the mixture is emulsified (dispersed) and charged with polyisocyanate. (2) An organic medium is added to a mixture of a dispersant, a polyol, and a polyisocyanate to emulsify, and a chain extender is charged immediately after that or after the reaction is allowed to proceed. (3) A dispersant, a polyol and a polyisocyanate are reacted in advance to form a prepolymer, an organic medium is added and emulsified, and a chain extender is charged. There is a method such as. The catalyst may be charged at any time, but it is preferable to charge it after the total amount has been charged.

The particulate polyurethane thus obtained may contain methanol, if necessary, during or after the reaction.
A suitable blocking agent having one active hydrogen atom in the molecule, such as ε-caprolactam, methyl ethyl ketone oxime, and phenol, can be added and reacted for stabilization.
The dispersion solution can be used as it is as a paint or an adhesive. The particulate polyurethane thus obtained can be recovered from the dispersion solution by filtering or decanting and then drying under normal pressure or reduced pressure. The obtained polyurethane powder had an average particle size of 0.
The particles are in the range of 1 to 2000 μm and more. The powder can be widely used in various molding materials, powder coatings, various modifiers, fillers and the like.

[0019]

EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 (1) Synthesis of polyol having unsaturated bond in molecule In a 2-liter four-necked flask, a stirrer, thermometer, distilling tower, N 2
_{2 With a} gas introduction tube, measure 660 g of adipic acid, 98 g of maleic anhydride, 410 g of ethylene glycol, and 0.05 g of stannous octoate. Heat and mix while flowing N ₂ gas. After the condensed water was discharged from the system at 120 to 160 ° C., the reaction was continued while gradually reducing the pressure in the system, and finally the reaction was completed at 190 ° C. and 30 mmHg for 4 hours, and then the reaction was terminated. The obtained polyester has a hydroxyl value of 104 mgKOH.
/ G, the acid value was 2.6 mgKOH / g. This polyester has a molecular weight of 1170 and has an average of 1 mol of double bonds in one molecule. (2) Synthesis of dispersant 74 g of polyol synthesized in (1), equipped with a stirrer, thermometer, dropping funnel and condenser in a 500 ml four-necked flask.
Weigh 99 g of butyl acetate. N ₂ gas is heated and mixed while flowing into the system from the upper part of the dropping funnel. When the temperature reached 110 ° C., a solution mixture of 74 g of 2-ethylhexyl metaarylate and 1.5 g of benzoyl peroxide was added dropwise from a dropping funnel. The dropping was completed in 1 hour, and then the reaction was completed at 130 ° C. for 2 hours. The hydroxyl value of this dispersant was 41 mgKOH / g. (3) Synthesis of Polyurethane Powder A 500 ml four-neck separable flask was equipped with a propeller-type blade stirrer, a thermometer, and a condenser, and the dispersant obtained in (2) was 9.1 g (0.003 mol), 60. Poly (ethylene adipate) diol 5 with a molecular weight of 1000 heated to ℃ 5
7.2 g (0.057 mol) and 5.1 g (0.057 mol) of 1,4-butanediol are charged and uniformly mixed.
29.3 g of diphenylmethane diisocineate at 50 ° C
(0.117 mol) is added and mixed homogeneously, and then 91 g of Shellzol 71 (Shell Chemical, paraffin having a boiling point of 170 to 200 ° C.) is added and stirred to emulsify. Next, 0.01 g of dibutyltin dilaurate was added, and the mixture was reacted for 1 hour at room temperature. Further, the temperature was raised to 70 ° C. and the reaction was carried out for 3 hours to obtain a particulate polyurethane polymer dispersed in Shell-Zol 71. This dispersion was allowed to stand, the supernatant was removed by decantation, and dried under reduced pressure to obtain a polyurethane powder. This powder has a main particle size of about 20 to 150 μm.
Met.

Example 2 (1) Synthesis of Polyol Having Unsaturated Bond in Molecule In a flask similar to that used in Example 1, (1), poly (butylene adipate) diol having a molecular weight of 1000 (trade name: Nipolan 4009, manufactured by Nippon Polyurethane Industry Co., Ltd., a hydroxyl value of 110 mgKOH / g) of 1000 g and maleic anhydride of 49 g are weighed and mixed by heating while flowing N ₂ gas. After the condensed water was discharged from the system at 140 to 160 ° C., the reaction was continued while gradually reducing the pressure in the system, and finally 190
After reacting for 4 hours under the conditions of 30 ° C and 30 mmHg, the reaction was terminated. The polyester has a hydroxyl value of 53 mgKOH / g and an acid value of 4.
It was 1 mgKOH / g. This polyester has a molecular weight of 21
00 has an average of 1 mol of double bonds in one molecule. (2) Synthesis of dispersant In a flask similar to that used in Example 1, (2),
Weigh 44 g of the polyol synthesized in (1) and 99 g of butyl acetate. N ₂ gas is heated and mixed while flowing into the system from the upper part of the dropping funnel. When it reaches 110 ℃,
2-Ethylhexyl methacrylate 5 from the dropping funnel
A solution mixture of 1 g, 51 g of lauryl methacrylate and 2 g of benzoyl peroxide is added dropwise. 1
The dropwise addition was completed in half an hour, and then the reaction was completed at 130 ° C. for 2 hours. The hydroxyl value of this dispersant is 11 mgKOH /
It was g. (3) Synthesis of Polyurethane Powder In the same flask as used in Example 1, (3),
18.2 g (0.002 mol) of the dispersant obtained in (2), Nippon Polan 4009 heated to 60 ° C., 57.2
g (0.056 mol), 1,4-butanediol 5.0
g (0.056 g mol) is charged and mixed uniformly. Fifty
28.5 g of diphenylmethane diisocyanate at ℃
(0.114 mol) was added and uniformly mixed, and then IP Solvent 1620 (manufactured by Idemitsu Petrochemical, boiling point 170 to 20)
Add 90 g of paraffin at 0 ° C., stir and emulsify.
Then add 0.01 g of dibutyltin laurate and add 1
The reaction was carried out at room temperature for an hour. Further, the temperature was raised to 70 ° C. and the reaction was carried out for 3 hours to obtain a particulate polyurethane polymer dispersed in the IP solvent. This dispersion zone was left standing, the supernatant was removed by decantation, and dried under reduced pressure to obtain a polyurethane powder. This powder has a main particle size of about 10 to 130.
was μm.

Example 3 (1) Synthesis of Polyol Having Unsaturated Bond in Molecule In the same flask as used in Example 1, (1), poly (hexamethylene carbonate) diol having a molecular weight of 1000 (trade name Nipporane) was used. 981, manufactured by Nippon Polyurethane Industry Co., Ltd., hydroxyl value 115 mg KOH / g) 980 g and maleic anhydride 49 g were weighed and reacted in the same manner as in Example 1, (1). The obtained polyol has a hydroxyl value of 57 m.
It was gKOH / g and the acid value was 4.2 mgKOH / g. This polyol has a molecular weight of 1970 and has an average of 1 mol of double bonds in one molecule. (2) Synthesis of dispersant In a flask similar to that used in Example 1, (2),
Weigh 44 g of the polyol synthesized in (1) and 99 g of butyl acetate. N ₂ gas is heated and mixed while flowing into the system from the upper part of the dropping funnel. When it reaches 110 ℃,
From the dropping funnel, a dissolution mixture of 103 g of lauryl methacrylate and 2 g of benzoyl peroxide is added dropwise. The dropping was completed in 1 hour and a half, and then the reaction was completed at 130 ° C. for 2 hours. The hydroxyl value of this dispersant is 1
It was 3 mgKOH / g. (3) Synthesis of Polyurethane Powder In the same flask as used in Example 1, (3),
9.1 g (0.001 mol) of the dispersant obtained in (2),
Poly (hexamethylene carbonate) diol having a molecular weight of 2000 and heated to 70 ° C. (trade name: Nipolan 980,
Made by Nippon Polyurethane Industry, hydroxyl value 56.9 mgKOH /
67 g (0.034 mol) of g) and 6.1 g (0.068 mol) of 1,4-butanediol are charged and mixed uniformly. Hexamethylene diisocine ate 17.3g
(0.103 mol) is added and mixed uniformly, then 90 g of SHERZOLE 71 is added and stirred to emulsify. Next, 0.03 g of dibutyltin dilaurate was added, and the mixture was reacted for 1 hour at room temperature. Further, the temperature was raised to 90 ° C., and the reaction was carried out for 5 hours to obtain a particulate polyurethane polymer dispersed in Shell-Zol 71. This dispersion was allowed to stand, the supernatant was removed by decantation, and dried under reduced pressure to obtain a polyurethane powder. The main particle system of this powder is 40-150μ
It was m. Next, a sheet was formed from the powder. 200 x 200 mm iron plate coated with silicone release agent
The polyurethane powder of the present invention was dropped on this iron plate and melt-molded. After cooling, remove the sheet,
A molded product having a thickness of about 1 mm was obtained. After heating this molded product for 2 days at 80 ° C., the surface condition of the molded product was observed, but no bleeding of the dispersant was observed.

Example 4 Polyurethane powder was synthesized using the dispersant synthesized in Example 3. The dispersant 9.1 obtained in Example 3, (2) was placed in the same flask as used in Example 1, (3).
g (0.001 mol), molecular weight 100 heated to 70 ° C
0 of poly (hexamethylene carbonate) diol (Nipporan 981, hydroxyl value 115 mg KOH / g) of 55.
7 g (0.057 mol), 1,4-butanediol 5.
Charge 1 g (0.057 mol) and mix evenly.
4,4'-dicyclohexylmethane diisocyanate 3
After 0.1 g (0.115 mol) is added and mixed uniformly, 100 g of SHERZOL 71 is added and stirred to emulsify. Next, 0.03 g of dibutyltin dilaurate was added, and the mixture was reacted for 1 hour at room temperature. Further, the temperature was raised to 90 ° C., and the reaction was performed for 6 hours to obtain a particulate polyurethane polymer dispersed in Shell-Zol 71. The solvent was removed from this dispersion under reduced pressure to obtain a polyurethane powder. The main particle diameter of the powder was 20 to 150 μm. This polyurethane powder was formed into a sheet by the same method as in Example 3 (3). Further, it was pressed under a pressing condition of 160 to 180 ° C. and 15 to 20 kg / cm ² for 5 minutes to obtain a sheet having a thickness of 0.5 mm.
When the mechanical strength of the sheet was measured by the method of JIS K6723, the tensile strength was 530 kg / cm ² , and the elongation was 280%.
Met.

Example 5 28.5 g of diphenylmethane diisocyanate used in Example 2, (3) was changed to 18.9 g (0.114 mol) of 1,4-cyclohexyl diisocyanate, and the amount of dibutyltin dilaurate was changed from 0.01 g to 0. Polyurethane powder was synthesized in the same manner as in Example 2 and (3) except that the amount of the reaction mixture was adjusted to 03 g, and the reaction time at 70 ° C. for 3 hours was changed to 90 ° C. for 6 hours. The polyurethane powder thus obtained had a main particle size of about 10 to 100 μm. Comparative Example 1 (1) Synthesis of Dispersant In the same manner as that used in Example 1 and (2), 97.7 g of Shellzol 71 was charged into a flask, and N ₂ gas was flown into the system from the upper part of the dropping funnel. Heated. 119 g (0.47 g) of lauryl methacrylate prepared in advance
Mol), 27.5 g (0.28 mol) of methyl methacrylate and 2.5 g of benzoyl peroxide were added dropwise with stirring at the same temperature over 2 hours. 140
The temperature was raised to ° C and the reaction was carried out for 4 hours to obtain a dispersant. (2) Synthesis of Polyurethane Powder The emulsion was emulsified in the same manner as in Example 1 (3) except that 9.1 g of the dispersant of (1) was used. As a result, the reactant was poorly dispersed in Shelsol 71 and became a lump.

[0024]

The dispersant for non-aqueous dispersion polymerization obtained according to the present invention has excellent dispersibility in the production of polyurethane powder, and further reacts with the polyisocyanate which is a constituent component, so that the molded article bleeds. And has excellent physical properties. Further, the polyurethane dispersion using the dispersant can be used as a paint or an adhesive as it is as a dispersion solution. The polyurethane powder obtained by the present invention has a wide range of applications such as various molding materials, powder coatings, various modifiers, and fillers.

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[Procedure amendment]

[Submission date] December 22, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Polyurethane composition using dispersant for non-aqueous dispersion polymerization

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The reaction between the polyol having an unsaturated bond and the ethylenically unsaturated monomer in the present invention is not particularly limited, and a usual method for polymerizing an ethylenic monomer using a radical initiator or the like as a reaction initiator. Is available. In the reaction of the present invention, a solvent can be used if necessary. For example, butyl acetate, cyclohexane, n-heptane, and other solvents commonly used for the polymerization of ethylenic monomers can be used. Furthermore, the amount ratio of the polyol having an unsaturated bond and the ethylenically unsaturated monomer of the present invention is preferably 100/20 to 400 (weight). The ethylene
The reaction initiator is added in an amount of 0.4 to 8.
1 part by weight can be used. When the amount of the ethylenically unsaturated monomer is less than 20 parts by weight based on 100 parts by weight of the polyol, the performance as a dispersant is deteriorated, and it is necessary to increase the amount of the dispersant charged when producing a polyurethane, which is economical. Will be disadvantageous. When the amount of the ethylenically unsaturated monomer exceeds 400 parts by weight with respect to 100 parts by weight of the polyol, the polar and nonpolar balance is lost during the non-aqueous dispersion polymerization, and the effect as the dispersant cannot be exhibited.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009] non-aqueous dispersion polymerization dispersant of the present invention can be used as a dispersing agent in the manufacture of Pouretan in non-aqueous dispersion polymerization method, as the polyurethane, conventional thermal-friendly plastic polyurethane resin, An incomplete thermoplastic polyurethane resin containing an isocyanate group or a blocked isocyanate group as necessary, a thermosetting polyurethane resin, or the like.

Claims (1)

[Claims] 1. A polyol 1 having an unsaturated bond in the molecule.
A dispersant for non-aqueous dispersion polymerization obtained by reacting 00 parts by weight with 20 to 400 parts by weight of an ethylenically unsaturated monomer having a side chain composed of a hydrocarbon group having 6 or more carbon atoms, polyisocyanate, and polyol, A polyurethane composition comprising a chain extender.