JPH01168703A - Dispersant for preversed-phase suspension polymerization - Google Patents

Abstract

PURPOSE:To provide the title dispersant capable of providing a bead polymer having a large particle diameter and excellent water absorption property etc., by constituting a copolymer of a specified MW made of a vinyl monomer having a polyalkylene glycol chain in its molecule. CONSTITUTION:A copolymer having an average MW in the range of 1,000-1,000,000 is prepd. by copolymerizing a vinyl monomer having a polyethylene glycol chain and/or a polypropylene glycol chain in its molecule (e.g., methoxypolyethylene glycol methacrylate or polypropylene glycol diacrylate) and a copolymerizable monomer (e.g., acylic acid or stearyl acrylate) in the presence of an initiator (e.g., benzoyl peroxide). A polymer is prepd. by using the copolymer thus obtd. as a dispersant for reverse-phase suspension polymn.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is a dispersant for reverse-phase suspension polymerization, particularly suitable for use in water-in-oil type reverse-phase suspension polymerization to produce bead-shaped polymers. This invention relates to a dispersant for polymerization.

[Conventional technology]

When manufacturing polymers by suspension polymerization, various dispersants are used to stabilize the suspension polymerization, to stabilize the dispersion of an aqueous polymer solution, and to prevent the produced polymer particles from agglomerating. Specifically, when producing bead-shaped polymers by dispersing an aqueous solution containing a water-soluble vinyl monomer in a water-insoluble organic solvent and performing water-in-oil reverse phase suspension polymerization, sorbitan has already been used. Nonionic surfactants such as monostearate, sorbitan monooleate, ethoxylated aliphatic amides, and glycerin fatty acid esters are used as dispersants. However, when these dispersants are used, the resulting polymer becomes fine particles, causing problems such as agglomeration or dust formation during the drying process.

In addition, copolymers containing lipophilic ethylenically unsaturated monomers such as cellulose ethers such as ethyl cellulose and ethyl hydroxycellulose, cellulose acetate, cellulose esters of cellulose butyrate, maleated polyethylene, and maleated α-olefins, etc. Polymer dispersants are used. However, when these polymer dispersants are used, the particle size of the synthesized polymer increases and the above problem can be solved, but the surface of the resulting polymer particles becomes hydrophobic and the polymer particles become larger. There is a problem that the wettability of the surface deteriorates. Furthermore, problems arose in that the stability of the emulsion used for suspension polymerization deteriorated and the performance of the resulting polymer itself deteriorated.

Furthermore, a method of using a copolymer of styrene/dimethylaminoethyl methacrylate/glycidyl methacrylate as a dispersant is already known (Japanese Patent Laid-Open No. 61-73
No. 704), but in the conventional synthesis method, the glycidyl groups cause crosslinking during synthesis, resulting in poor solubility of the resulting copolymer, and furthermore, when used as a dispersant, the stability of the emulsion formed deteriorates. . If a large amount of glycidyl groups are introduced, crosslinking will progress accordingly, resulting in insolubility in solvents, which is even more undesirable.

[Problem that the invention seeks to solve]

Therefore, it is an object of the present invention to provide a dispersant for reverse-phase suspension polymerization, in which polymer particles obtained by polymerization by reverse-phase suspension polymerization have a large particle size and have excellent wettability on the particle surface. purpose.

[Means for solving problems]

The present invention was made based on the knowledge that the above problems can be effectively solved by using a copolymer whose constituent monomer is a monomer component having a polyethylene glycol chain or a polypropylene glycol chain in the molecule as the dispersant. .

That is, the present invention provides a copolymer of a vinyl monomer A having a polyethylene glycol chain and/or a polypropylene glycol chain in the molecule and a monomer B copolymerizable with the monomer, and having an average molecular weight of 1.000 to 1.0.
Provided is a dispersant for reverse phase suspension polymerization, characterized in that the dispersant has a molecular weight of 0.00.000.

The following monomers (
It is preferable to use A-1) and/or (A-2).

Monomer (A-1) Polyethylene glycol having a polyethylene glycol chain (p=2-200) (meth)acrylate, methoxypolyethylene glycol (P=2-200)
Alkoxypolyethylene glycol (meth)acrylate such as (meth)acrylate, phenoxypolyethylene glycol (P=4-200) (meth)acrylate or phenoxyethyloxyethyl acrylate, methacryloyloxyethyl hydrogen succinate, 3-chloro-2-hydroxy Monoesters such as propyl methacrylate, polypropylene glycol (meth)acrylate having a polypropylene glycol chain,
Examples include diesters such as polyethylene glycol di(meth)acrylate or polybrobylene glycol di(meth)acrylate having a polyethylene glycol chain. These vinyl monomers can be used alone or as a mixture of two or more. As the vinyl monomer used in the present invention, methoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate and polybrobylene glycol di(meth)acrylate are preferred.

The polyethylene glycol chain or polypropylene glycol chain in these vinyl monomers has a corresponding alkylene oxide of 200 or less on average, preferably 2
-200, more preferably 2-100. In the above formula, 100 indicates the average number of moles of the corresponding alkylene oxide added (the same applies hereinafter).

Monomer (A-2) A vinyl monomer represented by the following general formula [I] is used.

R,0-(CH,Ctl,0)n-(CHCHO),
-C-R2...[I:1 (wherein, R1 has 1 to 1 carbon atoms)
6 alkyl group, Hue I? 1 R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms), and n
is 2 to 200, and m is 0 to 100. )in particular,
methoxypolyethylene glycol (meth)acrylate having a polyethylene glycol chain of n=2 to 200,
Monoesters such as ethoxypolyethylene glycol (meth)acrylate and phenoxypolyethylene glycol (meth)acrylate; diesters such as polyethylene glycol di(meth)acrylate having a polyethylene glycol chain of n=2 to 200; Mention may be made of monoesters and diesters such as methoxypolyethylene glycol polypropylene glycol (meth)acrylate and polyethylene glycol polypropylene glycol di(meth)acrylate having a polypropylene glycol chain and a polyethylene glycol chain with n=2-:2oO.

These can be used alone or as a mixture of two or more, but n = 2 to 200, more preferably 2 to 200.
It is preferable to use at least one type of 100 methoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, or the like.

As the monomer B to be copolymerized with the monomer A, the following monomers (B-1) and/or (B-2) and/or (B-3) are preferably used.

Monomer (B-1) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, etc.
meth) Hydroxyalkyl acrylates, unsaturated sulfonic acids such as acrylamide methylpropanesulfonic acid, allylsulfonic acid, alkylene imines such as ethyleneimine, propyleneimine, 1゜1'-dimethylethyleneimine, vinylpyridine, methylvinylpyridine N- such as vinylpyridine neck, N-vinylcarbazole, N-vinyl-1,2,3,4-tetracarbacy, etc.
Vinyl carbazoles, vinylamines such as N,N'-divinylamine, aminomethyl (meth)acrylate,
Aminoethyl (meth)acrylate, N-methylaminoethyl (meth)acrylate, N-ethylaminoethyl (meth)acrylate), N,N'-dimethylamino (
Examples include one type or a mixture of two or more types of (meth)acrylamides such as meth)acrylate and N,N'-diethylamino (meth)acrylate.

Chizuma (B-2) Unsaturated carboxylic acid esters such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid having an alkyl group having 1 to 24 carbon atoms, alkyl such as vinyl acetate, vinyl propionate, vinyl butyrate, etc. Vinyl esters, alkyl vinyl ethers such as butyl vinyl ether, 2-ethylhexyl vinyl ether, cetyl vinyl ether, stearyl vinyl ether, olefins or diolefins such as ethylene, propylene, butene, butadiene, styrene, vinylopear chloride, acrylonitrile, carbon number 12 ~
Examples include one kind or a mixture of two or more kinds of α-olefins such as 36 α-olefins. Among the monomers (B-2), preferred monomers include unsaturated carboxylic acid esters such as acrylic acid and methacrylic acid having an alkyl group having 6 to 24 carbon atoms, and alkyl vinyl esters such as vinyl acetate, vinyl propionate, and vinyl butyrate. , alkyl vinyl ether having an alkyl group having 6 to 24 carbon atoms, olefin such as ethylene, propylene, butene, butadiene, diolefin, styrene, vinyl chloride, α having 12 to 36 carbon atoms
- Examples include olefins.

Monomer (B-3) A vinyl monomer having at least one group selected from an epoxy group, a carboxylic acid anhydride group, and an incyanate group. These monomers as reactive vinyl monomers (
Among B-3), monomers having epoxy groups such as glycidyl (meth)acrylate, incyanate groups such as butene diisocyanate, 1゜3-butadiene-1,4-diisocyanate, 2-phthielene-1,4-diisocyanate, etc. or a vinyl monomer having a carboxylic acid anhydride group such as maleic anhydride, methyl maleic anhydride, phenyl maleic anhydride, citraconic anhydride, and itaconic anhydride. These reactive vinyl monomers can be used singly or as a mixture of two or more, but glycidyl (meth)acrylate and maleic anhydride are particularly preferred.

In the present invention, the above monomers A and B can be copolymerized in any ratio, but A and B may be copolymerized at an A/B ratio of 0.005.
~2 (molar ratio, same below), preferably 0.01~2
The average molecular weight is 1,000 to 1,000.
,000, preferably 1.000 to 500.000.

In the present invention, monomer (A-2) is further added to monomer (B).
-2) and (B-3) are preferably copolymerized. In this case, especially (A-2)/(B-3)=0.05-20
(molar ratio): C(A-2) + (B-3))/(B
-2) is preferably 0.02 to 2 (molar ratio), since a dispersant with excellent properties such as enabling stable suspension polymerization with an extremely small amount can be obtained, so it is preferable. The form of polymerization may be arbitrary, and may be a random polymer, a block polymer, a graft polymer, etc. of monomers A and B. These can be polymerized, for example, by bulk polymerization, solution polymerization, emulsion polymerization, etc., but solution polymerization is preferably carried out.

Examples of initiators used in the synthesis of the dispersant for reversed-phase suspension polymerization of the present invention include diacyl peroxides such as benzoyl peroxide and lauroyl peroxide, and azobisisobutyronitrile) k%2. 2'-Azobis(4-methoxy-2,4-dimethylvaleronitrile), 2.2'-
Azobis(2,4-dimethylvaleronitrile), (1-
phenylethyl) azodiphenylmethane, dimethyl-2
, 2'-azobisisobutyrate, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(
1-cyclohexanecarbonitrile), 2,2'-azobis(2,4,4'-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2'-azobis(2- Examples include azo compounds such as methylpropyl), which are used in an amount of 0.01 to 5% by weight based on the total amount of monomers.

When the dispersant for reverse-phase suspension polymerization of the present invention is synthesized by solution polymerization, the solvents include n-pentane, cyclopenkune,
Aliphatic hydrocarbons such as n-hexane, cyclohexane, n-hebutane, methylcyclohexane, kerosene, aromatic hydrocarbons such as benzene, toluene, xylene, methyl alcohol, ethyl alcohol, isopropyl alcohol, N-butyl alcohol , aliphatic alcohols such as amyl alcohol, aliphatic ketones such as acetone and methyl ethyl ketone, and aliphatic esters such as ethyl acetate, and these may be used alone or as a mixture of two or more. Incidentally, it is preferable that the polymerization is carried out at a temperature of 40° C. or higher, and the reaction time is 1 to 24 hours.

More specifically, a total of 5 to 500 parts by weight of monomers A and B and a polymerization initiator are dissolved per 100 parts by weight of the above solvent, and polymerization is carried out by heating to 40°C or higher, preferably 40 to 200°C. Good.

When producing a polymer by reverse phase suspension polymerization using the dispersant of the present invention, the dispersant of the present invention is added to a hydrophobic dispersion medium at 0.00%.
It is preferable to add it in advance so that it becomes 1 to 25%.

Monomers used to produce polymers that can be polymerized using the dispersant of the present invention include water-soluble vinyl monomers, such as olefinically unsaturated carboxylic acids, olefinically unsaturated sulfonic acids, olefinically unsaturated ethers, and olefinically unsaturated Examples include vinyl monomers having polymerizable unsaturated groups such as amide. Specifically, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and sodium fumarate, and water-soluble salts thereof, and the water-soluble salts include alkali metal salts, alkaline earth metal salts, Examples include ammonium salts. Examples of the vinyl monomer having a sulfonic acid group include unsaturated sulfonic acids such as acrylamide methylpropanesulfonic acid and allylsulfonic acid. Examples of vinyl monomers having an amide group include (meth)acrylamide, dimethyl or diethylaminoethyl ester tertiary salts, or quaternary salts of (meth)acrylic acid. The above monomers can be used alone or as a mixture of two or more, and the monomers described in the section of the synthesis of the dispersant of the present invention can also be added in an amount of 50% by weight or less. In addition, the monomer concentration in reverse phase suspension polymerization is 15 to 80% by weight, preferably 30 to 80% by weight.
It is 70% by weight.

Solvents used when performing reverse phase suspension polymerization using the dispersant of the present invention include n-pentane, cyclopenkune, n-
Aliphatic hydrocarbons such as hexane, cyclohexane, n-hebutane, methylcyclohexane, kerosene, benzene,
Aromatic hydrocarbons such as toluene and xylene, aliphatic alcohols with 4 to 6 carbon atoms such as isopropyl alcohol, N-butyl alcohol, and amyl alcohol, aliphatic ketones such as acetone and methyl ethyl ketone, and aliphatic esters such as ethyl acetate. One type or a mixture of two or more types can be mentioned. Further, the amount of the solvent used is preferably in the range of 10 to 500 parts by weight per 100 parts by weight of the monomer aqueous solution.

Examples of initiators for reverse-phase suspension polymerization using the dispersant of the present invention include hydrogen peroxide, persulfates such as potassium persulfate and ammonium persulfate, potassium perchlorate, and sodium perchlorate. Examples include azo compounds such as perchloric acid and 2-carbamoylazoisobutyronitrile.

When performing reverse phase suspension polymerization using the dispersant of the present invention, additives such as a crosslinking agent or a chain transfer agent can be added. Examples of the crosslinking agent include polyallyl compounds such as N,N'-diacrylamide, diallylamine, diallyl methacrylate, triallyl cyanurate, and triallyl phosphate, divinylbenzene, N,
N'-methylenebisacrylamide, polyvinyl compounds such as ethylene glycol dimethacrylate, polyglycidyl ethers such as ethylene glycol diglycidyl ether and polyethylene glycol glycidyl ether, haloepoxy compounds such as epichlorohydrin, polyaldehydes such as gel taraldehyde, glycerin, etc. Polyols, polyamines such as ethylene diamine, hydroxyvinyl compounds such as 2-hydroxyethyl methacrylate, and inorganic or organic metal salts that generate polyvalent ions such as calcium, magnesium, and aluminum can be used. As a chain transfer agent,
For example, mercaptans, chloroform, carbon tetrachloride,
Isopropyl alcohol or the like can be used. Furthermore, monoglycidyl compounds such as phenol polyoxyethylene glycidyl ether can be used as a modifier.

Although the mechanism by which the dispersant of the present invention has excellent effects has not been fully explained, it is presumed as follows. That is, since the dispersant of the present invention has a polyethylene glycol chain or a polypropylene glycol chain as a group that imparts hydrophilicity in its molecule, it has a lipophilic group consisting of this hydrophilic portion and a copolymerized monomer that imparts lipophilicity. The part is
It has a molecular structure that cannot be obtained with general random copolymers. Therefore, when the dispersant of the present invention is used, polyethylene glycol chains, polypropylene glycol chains, etc. that impart hydrophilicity enter the aqueous phase side from the interface.
It is presumed that a stable emulsion can be formed by the lipophilic part made of the copolymerized monomer that imparts lipophilicity entering the oil phase from the interface.

Furthermore, the dispersant obtained by copolymerizing monomer (A-2) with monomers (B-2) and (B-3) has an epoxy group derived from monomer (B-3), which is a reactive vinyl monomer, Since the carboxylic anhydride group and isocyanate group are maintained as they are, when reverse phase suspension polymerization is performed using the dispersant and an unsaturated carboxylic acid such as acrylic acid as the polymerization monomer, It is speculated that the reactive group of the dispersant and the carboxyl group of the monomer acrylic acid react, making the interface stronger, and as a result, stable polymerization can be achieved even with a smaller amount of the dispersant used. be done.

〔Effect of the invention〕

According to the present invention, an aqueous solution containing one or more water-soluble vinyl monomers is dispersed in the monomer and an organic solvent insoluble in water, and water-in-oil reverse phase suspension polymerization is performed to form beads. In the production of polymers, an extremely excellent dispersant is provided that allows the production of bead-shaped polymers with large polymer particles and excellent water absorption properties or wettability.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

〔Example〕

Example 1 300 equipped with a stirrer, reflux condenser, and nitrogen gas inlet tube
In a three-neck flask of mf, 28.2 g (0,102 mol) of methoxypolyethylene glycol (p = 4) methacrylate (M-40G = manufactured by Shin Nakamura Chemical Industry), 37.2 g (0,115 mol) of stearyl acrylate) were added. mole), V-
65 (manufactured by Junsei Kagaku) 170 mg,) Add 70 g of toluene, stir, and blow nitrogen gas to drive out dissolved oxygen.
After raising the temperature to 65°, it was kept at that temperature for 9 hours to perform reaction and ripening. Next, toluene was distilled off to obtain a yellowish-white waxy polymer (dispersant A of the present invention). The average molecular weight of the polymer was 50,000, and it was a random polymer. In addition, ■-65 is 2.2'-azobis-(2,
4-dimethylvaleronitrile) (the same applies hereinafter).

Example 2 Various polymer dispersants were manufactured in the same manner as in Example 1 using the same equipment except that the various raw materials shown in Table 1 were used. Table 1 also shows the average degree of polymerization of the obtained polymer.
Shown below. In addition, the amount of each component in the table is g.

Example 3 300m equipped with a stirrer, reflux condenser, and nitrogen gas inlet pipe
j! In a three-neck flask, 1.54 g (0,0109 mol) of methoxypolyethylene glycol methacrylate (M-230G: Shin Nakamura Chemical Co., Ltd. > 12.2 g (0,0109 mol), glycidyl mechcrylate) was added.
mol), stearyl acrylate 63.4 g (
0,196 mol), V-65 (Junsei Kagaku) 1
70 mg, ) 100 g of toluene was added and stirred, nitrogen gas was blown in to drive out dissolved oxygen, the temperature was raised to 65°C, and the temperature was maintained for 9 hours to carry out reaction and ripening. Next, toluene was distilled off to obtain a yellowish-white waxy polymer (dispersant K of the present invention). The obtained polymer had an average molecular weight of 280.000 and was a random polymer.

Example 4 Various polymer dispersants were produced in the same manner as in Example 3 using the same equipment except that the various raw materials shown in Table 2 were used. The average molecular weight of the obtained polymer is also shown in Table 2.
Shown below. In addition, the amount of each component in the table is g.

Comparative Example 1 300 equipped with a stirrer, reflux condenser, and nitrogen gas introduction pipe
2.8 g of methacrylic acid (0
, 033 mol), glycidyl methacrylate 2, 32
g (0,016 mol), stearyl acrylate)
Add 49.3g (0,152mol), 170cm of V-65 (manufactured by Junsei Kagaku), and 100g of toluene and stir.
Dissolved oxygen was driven out by blowing in nitrogen gas, the temperature was raised to 65°C, and the temperature was maintained for 9 hours to carry out reaction and ripening. Next, toluene was distilled off to obtain a yellowish-white solid polymer (dispersant T).

Comparative example, 2 300m equipped with a stirrer, reflux condenser, and nitrogen gas introduction pipe
In the three-necked flask A', add 2.35 g of acrylic acid (0
,033 mol), glycidyl methacrylate 4,64
g (0,033 mol), stearyl acrylate,
) 55.1 g (0.17 mol), 170 g of V-65 (manufactured by Junsei Kagaku), and 100 g of toluene were added, stirred, nitrogen gas was blown in to drive out dissolved oxygen, and the temperature was raised to 65°C. The mixture was kept for 9 hours for reaction and aging. Next, toluene was distilled off to form a yellowish-white solid polymer (
A dispersant U) was obtained.

Comparative Example 3 300- equipped with a stirrer, reflux condenser, and nitrogen gas introduction tube
In a three-necked flask, 8.80 g (0,056 mol) of dimethylaminoethyl methacrylate, 4.64 g (0,033 mol) of glycidyl methacrylate,
Stearyl acrylate 55.1 g (0.17 mo
l), V-65 (manufactured by Gensei Kagaku) 170■, toluene 1
00g was added and stirred, nitrogen gas was blown in to drive out dissolved oxygen, the temperature was raised to 65°C, and the temperature was maintained for 9 hours for reaction and aging. Next, toluene was distilled off to obtain a yellowish-white solid polymer (dispersant V).

Table 3 summarizes the results of solubility and emulsion stability tests for the above dispersants.

Here, the dispersant Log was added to 100 g of the organic solvent at 30°C.
The solubility is considered to be good if it is completely dissolved.○)
In this case, the presence of insoluble matter was considered to be poor solubility (X). In addition, 0.3 g of dispersant and 30 g of cyclohexane were added to a 100 rnl emulsification cylinder and dissolved at 70°C, and 10 g of acrylic acid, 4.
After adding an aqueous solution consisting of 3 g and 13 g of water, shaking vigorously, and observing the emulsion after standing at 70°C for 1 minute, if the number of separated layers is 1 or less, the emulsion stability is considered to be good. , 1rn1 or more separation occurs, the emulsion stability is considered to be poor (×).

Table 3 Reference Example 1 300 g of cyclohexane and 3 g of dispersant A were added to a 11-four-bottle flask equipped with a stirrer, reflux condenser, dropping funnel, and nitrogen gas introduction tube, stirred, and nitrogen gas was blown to drive out dissolved oxygen. The temperature was raised to 70°C. Meanwhile, in another flask, 43 g of sodium hydroxide was dissolved in 130 g of water, and 100 g of acrylic acid was added thereto. 0.3 g of ammonium persulfate (APS), an initiator, was added and dissolved, and nitrogen gas was blown into the aqueous solution. An aqueous monomer solution was prepared by expelling dissolved oxygen.

Next, the monomer aqueous solution was added dropwise to the neck flask with thorough stirring at a speed of 40 rpm over 1 hour to polymerize the monomers, and the mixture was further aged for 3 hours. After aging, it was directly dried at 80° C. under reduced pressure to obtain a colorless bead-like polymer.

In addition, dispersant B-3 was used instead of dispersant A, but
The same effect as when using dispersant A was obtained in each case.

Reference Example 2 In Reference Example 1, the monomer aqueous solution was mixed with acrylic acid 10
0 g, 100 g water and ammonium persulfate (APS)
An experiment was carried out in the same manner as in Example 2, except that an aqueous solution containing 0.3 g was used, and a colorless bead-shaped polymer was obtained.

Further, although dispersant K was used in place of dispersant A, the same effect as when dispersant A was used was obtained.

Reference Example 3 300 ml of cyclohexane was placed in a IIl four-hole flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube.
g and 3 g of dispersant E were added and stirred, nitrogen gas was blown in to drive out dissolved oxygen, and the temperature was raised to 70°C. In another flask, 43 g of sodium hydroxide was dissolved in 130 g of water, and 100 g of acrylic acid was added to the resulting aqueous solution.
61 modified polyvinyl alcohol (manufactured by Nippon Gosei Co., Ltd., trade name Oks-3266> 4 g, ethylene glycol diglycidyl ether 25 mg, and cyclohexane 54 g
A monomer aqueous solution (0/w emulsion) was prepared by adding g and stirring, and blowing nitrogen gas to drive out dissolved oxygen.

Next, the O/W emulsion was added dropwise over 1 hour to polymerize the monomer while thoroughly stirring the four-hole flask at a speed of 400 rpm, and the mixture was further aged for 3 hours. Immediately after aging, the mixture was dried at 80° C. under reduced pressure to obtain a porous bead-like polymer.

Also, dispersant K was used instead of dispersant E, but dispersant E
The same effect was obtained when using .

Reference example 4 (for comparison) 300 g of cyclohexane was placed in 11 four-bottle flasks equipped with a stirrer, reflux condenser, dropping funnel, and nitrogen gas introduction tube.
and 3 g of dispersant T were added and stirred, nitrogen gas was blown in to drive out dissolved oxygen, and the temperature was raised to 70°C. Meanwhile, in another flask, 43 g of sodium hydroxide was dissolved in 130 g of water, and 100 g of acrylic acid was added to the resulting aqueous solution, which contained 0.3 g of ammonium persulfate (APS), an initiator.
was added and dissolved, and dissolved oxygen was removed by blowing in nitrogen gas to prepare an aqueous monomer solution.

Next, the aqueous monomer solution was added dropwise into the four-lobe flask with sufficient stirring at a speed of 40 rpm over 1 hour to polymerize the monomers, but aggregation occurred during the dropwise addition.

Further, when dispersant U or V was used instead of dispersant T, the same results as when dispersant T was used were obtained.

The polymerization stability and particle size of the obtained polymers in Reference Examples are summarized in Table 4. Here, the polymerization stability is considered to be good if a polymer of -order particles is obtained (○), and the polymerization stability is considered to be poor if agglomeration occurs during polymerization or secondary particles are obtained. (×)

Table-4 Reference Example 5 In Reference Example 1, using dispersant C instead of dispersant A,
And the amount of dispersant added is 6.0g, 3.0g, 1.5g,
An experiment was carried out in the same manner as in Reference Example 1, except that the amounts were 0.8 g and 0.4 g, and a colorless bead-shaped polymer was obtained.

Further, although dispersant E was used in place of dispersant C, similar results were obtained when dispersant C was used.

Reference Example 6 In Reference Example 1, using dispersant N instead of dispersant A,
And the amount of dispersant added was 6.0g and 3.0g.

An experiment was conducted in the same manner as in Reference Example 1, except that the amounts were 1.5 g, 0.8 g, and 0.4 g, and a colorless bead-shaped polymer was obtained.

Further, although dispersant 0 was used in place of the above-mentioned dispersant N, results similar to those obtained when dispersant N was used were obtained.

Reference example 7 (for comparison) In reference example 1, ethyl cellulose (N-50) was used instead of dispersant A, and the amount added was 6.0 g.
3.0 g, '1.5 g, 0.8 g and 0.4
An experiment was conducted in the same manner as in Reference Example 1, except that Example 1 was used in Example 1. Ethylcellulose made by Percules ■ was used.

Reference Example 8 (for comparison) In Reference Example 1, 6.0 g, 3.0 g,
An experiment was conducted in the same manner as in Reference Example 1, except that 1.5 g, 0.8 g, and 0.4 g were used. Table 5 shows the polymerization stability with respect to the amount of dispersant added in Reference Examples. Here, the polymerization stability is considered to be good if a few particles of polymer are obtained (○), and the polymerization stability is considered to be poor if aggregation occurs during polymerization or secondary particles are obtained. I did (×)
.

Reference Example 9 In Reference Example 1, using dispersant C instead of dispersant A,
After the addition was completed, an experiment was carried out in the same manner as in Reference Example 1, except that 61'mg of ethylene glycol diglycidyl ether (manufactured by Nagashio Sangyo) was added to the reaction system, to obtain a colorless bead-like polymer.

Further, although dispersant E was used in place of dispersant C, similar results were obtained when dispersant C was used.

Reference Example 10 In Reference Example 1, using dispersant N instead of dispersant A,
After the addition was completed, an experiment was carried out in the same manner as in Reference Example 1, except that 61 mg of ethylene glycol glycidyl ether (manufactured by Nagashio Sangyo) was added to the reaction system, to obtain a colorless bead-like polymer.

Further, in place of the above-mentioned dispersant N, the same results were obtained as in the case where force 1 was used and dispersant O was used, and when dispersant N was used.

Reference example 11 (for comparison) Reference example 1 except that 3 g of ethyl cellulose was used instead of dispersant A, and 61 mg of ethylene glycol diglycidyl ether (manufactured by Nagashio Sangyo) was added to the reaction system after the dropwise addition was completed. Conduct an experiment in the same manner as 1.
A colorless bead-like polymer was obtained.

Reference Example 12 (For Comparison) In Reference Example 1, 6 g of polyoxyethylene sorbitol stearate (Nippon Emulsion, Emarex EG2854-3) was used instead of dispersant A, and after the dropwise addition, ethylene glycol diglycidyl ether (Nagashio) was used. An experiment was conducted in the same manner as in Reference Example 1, except that 61 mg (manufactured by Sangyo) was added to the reaction system, and a colorless bead-shaped polymer was obtained.

The table summarizes the water absorption capacity and gel strength of the obtained polymer.
6. Here, the gel strength and physiological saline water absorption capacity were measured as follows.

O Physiological saline water absorption capacity 0.3 g of a water-absorbing resin was sealed in a non-woven fabric bag, and the bag was held horizontally so that the sample was evenly sprinkled on it. 300ml of this! After immersing horizontally in a Petri dish containing physiological saline for 30 minutes,
The sample was drained for 1 minute on a g-mesh screen tilted at an angle of 100 degrees, and the weight was measured. Separately, a nonwoven fabric bag containing no water-absorbing resin was measured using the above method, and this was used as a blank.

The blank was subtracted from the measured value thus obtained, and the value converted to the weight per 1 g of water absorbent resin was defined as the physiological saline water absorption capacity.

The larger this value is, the higher the water absorption is.

○ Gel strength measurement 100mI! 2 g of water absorbent resin was placed in a beaker, and 2 g of methanol was added to sufficiently wet the water absorbent resin. 40 g of ion-exchanged water was added to the mixture at once, and the mixture was shaken to avoid clumping, and the mixture was uniformly absorbed to prepare a sample. Next, using a rheometer (manufactured by Fudo Kogyo, NRM-2002J), this sample was raised at a speed of 2 cm/sec,
The stress 10 seconds after the adapter (a disk of φ10 mm) and the gel surface came into contact was measured, and this was taken as the gel strength. The larger this value is, the stronger the water-absorbing gel is.

Table 6 * For comparison, 1988, month and day, Mr. Kunio Ogawa, Commissioner of the Patent Office, 1, Indication of the case, 1988 Patent Application No. 329027
No. 2, Title of the invention Dispersant for reverse phase suspension polymerization 3. Relationship with the case of the person making the amendment Applicant name (676) Lion Co., Ltd. 4, Agent 5, Date of amendment order Voluntary 6, Subject of amendment Column 7 of detailed explanation of the invention in the specification, contents of amendment (1) “2cm/sec” in the fifth line from the bottom of page 39 of the specification
” is corrected to r 2 cm/min, J.

Claims (1)

Scope of Claims: (1) A copolymer of a vinyl monomer A having a polyethylene glycol chain and/or a polypropylene glycol chain in the molecule and a monomer B copolymerizable with the monomer, the average molecular weight being 1,000 to 1,000. A dispersant for reverse phase suspension polymerization, characterized in that the molecular weight is in the range of 1,000,000. (2) The dispersant according to claim (1), wherein the polyethylene glycol chain and the polypropylene glycol chain are polymers having an average of 200 or less of the corresponding alkylene oxide. (3) The dispersant according to claim (1), wherein the molar ratio of monomers A and B is in the range of 0.005 to 2.