JPH0753645A - Production of water-soluble grafted polymer - Google Patents

Abstract

PURPOSE:To provide a method, for producing a water-soluble grafted polymer having a high graft degree by grafting monoethylenic unsaturated monomers consisting mainly of (meth)acrylic acid to a polyether in a high content. CONSTITUTION:This method for producing a water-soluble grafted polymer comprises graft-polymerizing (B) a monomer component comprising (b1) 40-100mol.% of (meth)acrylic acid and (b2) 0-60mol.% of a copolymerizable monoethylenic unsaturated monomer to (A) a polyether compound containing 180mol.% of ethylene oxide as constituting units and having a number-average mol.wt. of >=200 in an amount (B) of >=25wt.% based on the polyether compound (A) in the presence of a polymerization initiator at >=100 deg.C substantially without using a solvent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyether having ethylene oxide as a main component and a monoethylenically unsaturated monomer having (meth) acrylic acid as a main component and a high graft ratio, that is, a polyether. The present invention relates to a method for producing a graft polymer, in which the amount of monoethylenically unsaturated monomer polymer not grafted onto is small.

[0002]

2. Description of the Related Art Attempts to graft-polymerize (meth) acrylic acid on a polyether compound have been made up to now in various fields of application such as polyurethane. For example, JP-A-5
In Japanese Patent Publication No. 5-71710, 3 to 15 w is added to the total charged amount.
A polymer obtained by graft-polymerizing t% acrylic acid on a polyoxyalkylene compound and a method for producing the same are disclosed.
However, in this case, when the obtained graft polymer is used as a dispersant such as a builder or an inorganic pigment, the amount of carboxylic acid is too small, so that satisfactory performance may not be obtained or the performance may be improved. Requires a very large amount of addition.

Further, in JP-A-59-62614, at least 20 wt% based on the graft polymer is added to a polyglycol ether having at least one hydrophobic group.
In the graft polymer obtained by graft-polymerizing the hydrophilic ethylenically unsaturated monomer and the method for producing the same, a method using a solvent of water or toluene, or a method in which the reaction temperature is 90 ° C. or lower without a solvent is disclosed. There is. The grafting efficiency of the graft polymer obtained by this method is low, and there are many ungrafted polymers. When this graft polymer is used as a dispersant such as a builder or an inorganic pigment, satisfactory performance is not obtained, and when it is used as a builder for a liquid detergent, the polymer is separated.

Further, JP-A-3-177406 also discloses a similar graft polymer obtained by polymerization in an aqueous solvent. However, the polymerization method of graft polymerization in the disclosed water solvent is poor in grafting efficiency, and many of the obtained polymers are ungrafted polycarboxylic acids, and when used in the above-mentioned applications, the desired performance is not obtained. There is a problem that you cannot get it.

As described above, according to the prior art, it has not been possible to easily produce a graft polymer having a high carboxylic acid density and a high grafting efficiency and having a small amount of ungrafted polymer.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a monoethylenically unsaturated monomer mainly composed of (meth) acrylic acid,
An object of the present invention is to provide a method for producing a water-soluble graft polymer which is grafted to a polyether in a high content and has a high graft ratio.

[0007]

Means for Solving the Problems The inventors of the present invention have improved the above-mentioned problems, and have conducted extensive studies as to a method for producing a water-soluble graft polymer having a high carboxylic acid density and a small amount of non-grafted polymer. The present invention has been completed.

In the present invention, ethylene oxide is added at 80mo
40% to 100 mol% of (meth) acrylic acid (b1), and other copolymerizable monoethylenically unsaturated monomer ((A)) having a number average molecular weight of 200 or more as a constituent unit of 1% or more. b2) The monomer component (B) consisting of 0 to 60 mol% is added to the polyether compound (A).
When the water-soluble graft polymer is obtained by graft polymerization in an amount of 25 wt% or more, the monomer component (B) is added to the polyether compound (A) substantially in the presence of a polymerization initiator. It is a production method characterized by carrying out a graft polymerization reaction at a temperature of 100 ° C. or higher without using it.

The polyether compound (A) used in the present invention has a number average molecular weight of 200 or more having ethylene oxide as a constituent unit of 80 mol% or more, and ethylene oxide and other alkylene oxides, water or alcohol. It is obtained by polymerizing by a known method as a starting point. As the alcohol for obtaining the polyether, for example, methanol, ethanol, n-propanol, n-butanol or the like having 1 to 1 carbon atoms is used.
22 primary alcohols; secondary alcohols having 3 to 18 carbon atoms; tertiary alcohols such as t-butanol; diols such as ethylene glycol, diethylene glycol, propanediol, butanediol, propylene glycol;
Examples include triols such as glycerin and trimethylolpropane; polyols such as sorbitol. The other alkylene oxide copolymerizable with ethylene oxide is not particularly limited, but propylene oxide,
Butylene oxide is preferred. Further, other alkylene oxide copolymerizable with ethylene oxide must be less than 20 mol% as a whole. 20 mol
If it is more than 100%, the graft ratio of the obtained graft polymer is lowered. Further, as the polyether compound (A), hydroxyl groups at all or some of the terminals of the polyether obtained as described above have C 2-22 fatty acids, succinic acid, succinic anhydride, and maleic acid. And those esterified with dicarboxylic acids such as maleic anhydride and adipic acid.

The molecular weight of these polyethers is 2
It is 00 or more, preferably 500 or more, more preferably 1000 or more. There is no particular upper limit of the molecular weight,
It is preferably 20,000 or less, and when the polyether has two or more hydroxyl groups, it is preferably 6000 or less.
When the molecular weight is less than 200, there is a problem that the amount of polyether not grafted increases.

In the present invention, the polyether compound (A)
In addition, (meth) acrylic acid (b1) 40 to 100 mol%,
And a monomer component (B) consisting of 0 to 60 mol% of another monoethylenically unsaturated monomer (b2) which is copolymerizable,
25w for 100wt% of polyether compound (A)
Graft polymerization is required for t% or more. It is more preferable that 20 wt% or more of acrylic acid as the component (b1) of the monomer component (B) is graft-polymerized with respect to 100 wt% of the polyether compound (A). If it is less than 25 wt%, the density of the carboxylic acid of the obtained graft polymer is small, and various performances such as polyvalent metal ion chelating ability and dispersing ability are not satisfied.

Other monoethylenically unsaturated monomers (b2) copolymerizable with (meth) acrylic acid (b1) include, for example, maleic acid; fumaric acid; maleic anhydride; dimethyl maleate, diethyl maleate. Such as alkyl esters of maleic acid; dimethyl fumarate, diethyl fumarate and other fumaric acid alkyl esters; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, stearyl (meth) acrylate, etc. Alkyl (meth) acrylate; hydroxyalkyl (meth) acrylate such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; acetic acid alkenyl ester such as vinyl acetate; aromatic vinyl such as styrene; (meth) acrylonitrile,
(Meth) acrolein, (meth) acrylamide; dialkylaminoethyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; 2-acrylamido-2-methylpropanesulfonic acid, and the like. One or two of these are listed. More than one species can be used. Among these, maleic acid, fumaric acid, and maleic anhydride are preferable from the viewpoint of increasing the carboxylic acid density of the graft polymer and increasing the polyvalent metal ion chelating ability and the dispersing ability.

When at least one selected from the group consisting of maleic acid, fumaric acid and maleic anhydride is used as the (meth) acrylic acid (b1) and the other copolymerizable monomer component (b2), It is particularly preferable that after mixing half or more of b2) with the polyether compound (A) in advance, the remaining monomer component (B) and the polymerization initiator are added and graft polymerization is carried out. By this method, the introduction rate of maleic acid, fumaric acid, and maleic anhydride into the graft polymer can be significantly improved.

The copolymerization ratio of the (meth) acrylic acid (b1) and the other copolymerizable monoethylenically unsaturated monomer (b2) is such that (b1) is 40 to 100 mol% and (b2) is 0. ~ 60
It is mol%. When the monomer (b2) is a monomer having no carboxyl group, the copolymerization ratio of (b1) is 80
˜100 mol%, and the monomer (b2) is preferably 0 to 20 mol%. When the monomer (b2) is a monomer having no carboxyl group, (meth) acrylic acid is 80 mol%
When the amount is less, the density of the carboxylic acid of the obtained graft polymer is low, and the properties such as polyvalent metal ion chelating ability and dispersing ability are not satisfied. When (b2) is a carboxyl group-containing monomer such as maleic acid, fumaric acid, and maleic anhydride, even if the amount of (meth) acrylic acid is less than 40 mol%, the carboxylic acid density of the resulting graft polymer decreases. It does not happen, but in this case (meth) acrylic acid is 40m
If it is less than ol%, there is a problem that the introduction rate of maleic acid, fumaric acid, maleic anhydride or the like into the graft polymer is lowered, and the amount of remaining monomers is increased.

Graft polymerization is carried out in the presence of a polymerization initiator,
It is carried out substantially without solvent.

As the polymerization initiator, known radical initiators can be used, but organic peroxides are particularly preferable.

Examples of organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 2 , 5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3
-Hydroperoxides such as tetramethylbutyl hydroperoxide; di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxy) p
-Dialkyl peroxides such as diisopropylbenzene, α, α'-bis (t-butylperoxy) p-diisopropylhexyne; t-butylperoxyacetate, t-butylperoxylaurate, t-butylperoxybenzoate , Di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, peroxyesters such as t-butylperoxyisopropyl carbonate; n-butyl-4,4 Examples include peroxyketals such as -bis (t-butylperoxy) valeate and 2,2-bis (t-butylperoxy) butane; diacyl peroxides such as dibenzoyl peroxide.

The amount of the polymerization initiator is not particularly limited, but it is preferably 0.1 to the monoethylenically unsaturated monomer.
15% by weight, more preferably 0.5 to 10% by weight is used. If it is less or more than this, the grafting efficiency of the monomer to the polyether is lowered. Further, the polymerization initiator can be added to the polyether in advance,
It can also be added at the same time as the monoethylenically unsaturated monomer.

Graft polymerization is carried out substantially without solvent. When water or an organic solvent such as alcohol or toluene is used, the efficiency of grafting the monomer to the polyether is lowered. When a solvent is used to add an initiator or a monomer, the amount thereof should be as small as possible, preferably 5w based on the total amount.
It is preferable to reduce the amount to t% or less, or to immediately distill off from the reaction system after the addition.

The polymerization temperature is 100 ° C. or higher, preferably 11
It is performed at 0 ° C or higher and 160 ° C or lower. If the temperature is lower than 100 ° C, the efficiency of grafting the monomer to the polyether is lowered. Further, at a temperature higher than 160 ° C, thermal decomposition of the polyether and the graft polymer may occur.

In the graft polymerization, it is preferable that the polyether compound (A) is initially charged in a part or the whole amount. When maleic acid, fumaric acid or maleic anhydride is used as the monomer (b2), it is preferable to initially charge half or more of the amount of the monomer (b2) used together with the polyether compound (A). . Then, the remaining monomers and the initiator are separately added dropwise after heating the polyether to 100 ° C. or higher. At this time, when a part of the polyether compound (A) is initially charged, the remaining polyether compound (A) may be mixed with an initiator or a monomer and added dropwise.

The resulting polymer can be used as a dispersant or scale inhibitor by dissolving it in a solvent such as water or alcohol as it is, or by adding a base. Examples of the base include monovalent metal salts such as sodium salts and potassium salts, divalent metal salts such as calcium salts, trivalent metal salts such as aluminum salts, ammonium salts, organic amine salts such as monoethanolamine and triethanolamine. Can be mentioned. In that case, water is preferable as the solvent.

The water-soluble graft polymer obtained by the production method of the present invention exhibits good performance as a dispersant for a water-insoluble inorganic or organic substance. For example, it exhibits good performance as a dispersant for inorganic pigments such as heavy or light calcium carbonate and clay used for paper coating, and a dispersant for water slurry such as cement and coal. In addition, it is also used for cooling water system, boiler water system, seawater desalination equipment, pulp digester, water treatment agent for scale prevention in black liquor concentrator, and fiber treatment agents such as dyeing aids and antistatic aids for fibers. can do.

Further, the water-soluble graft polymer obtained by the production method of the present invention can be used as a water absorbent resin by crosslinking with a crosslinking agent. Since the water-soluble graft polymer obtained by the production method of the present invention has a high graft ratio, the water-absorbent resin obtained by cross-linking with a cross-linking agent has a small amount of soluble components, and since the main chain contains a polyether, it has salt resistance. A highly water-absorbent resin can be obtained. The crosslinking is carried out by a known method and is not particularly limited, but it is preferably carried out by reacting the carboxylic acid of the graft polymer with the crosslinking agent.

[0025]

【Example】

-Example 1-A glass reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 100 parts by weight of polyethylene glycol having an average molecular weight of 3000, and heated under a nitrogen stream to be melted and stirred. The temperature was raised to 145 ° C. below. Next, while maintaining the temperature at 145 to 147 ° C., 50 parts by weight of acrylic acid and 2.5 parts by weight of di-t-butylperoxide were separately added dropwise continuously over 1 hour, and then stirring was continued for 20 minutes. It was After cooling, a sodium hydroxide aqueous solution (10% solution) in a completely neutralized amount of acrylic acid was added dropwise, and the mixture was heated at reflux temperature for 1 hour with stirring to obtain an aqueous sodium salt solution of graft polymer 1.

-Example 2-A reactor similar to that of Example 1 was charged with 100 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000, heated under a nitrogen stream to melt, and stirred at 130 ° C.
The temperature was raised to. Next, while maintaining the temperature at 130 to 132 ° C., 66.8 parts by weight of acrylic acid and 5 parts by weight of t-butylperoxide were separately added dropwise over 1 hour, and then stirring was continued for 80 minutes. After cooling, a sodium hydroxide aqueous solution (10
% Solution), and the mixture was heated at reflux temperature with stirring for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 2.

Example 3 A reactor similar to that in Example 1 was charged with 70 parts by weight of polyethylene glycol having an average molecular weight of 2000, heated and melted under a nitrogen stream, and heated to 145 ° C. under stirring. . Next, while maintaining the temperature at 146 to 147 ° C., 30 parts by weight of acrylic acid, di-t-butylperoxide 0.
3 parts by weight are separately added dropwise continuously over 1 hour,
Then, stirring was continued for 1 hour. After cooling, a sodium hydroxide aqueous solution (10% solution) in a completely neutralized amount of acrylic acid was added dropwise, and the mixture was heated at reflux temperature for 1 hour with stirring to obtain an aqueous sodium salt solution of graft polymer 3.

Example 4 A reactor similar to that of Example 1 was charged with 70 parts by weight of polyethylene glycol having an average molecular weight of 3000, heated under a nitrogen stream to melt, and heated to 150 ° C. under stirring. . Next, while maintaining the temperature at 150 to 152 ° C., 30 parts by weight of methacrylic acid and 1.5 parts by weight of di-t-butylperoxide were separately and continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes. It was After cooling, a sodium hydroxide aqueous solution (1
0% solution) and heated at reflux temperature for 1 hour with stirring,
An aqueous sodium salt solution of the graft polymer 4 was obtained.

Example 5 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000 and 13.9 parts of maleic acid and heated under a nitrogen stream to be melt mixed. The temperature was raised to 145 ° C. with stirring. Next, while maintaining the temperature at 145 to 147 ° C., 19 parts by weight of acrylic acid and 1.7 parts by weight of di-t-butylperoxide were separately and continuously added dropwise over 1 hour, and then stirring was continued for 1 hour. It was After cooling, aqueous sodium hydroxide solution (10%
(Solution) was added with stirring to an amount of about 11 and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 5.

Example 6 A reactor similar to that of Example 1 was charged with 40 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000 and 20.9 parts by weight of maleic acid and heated under a nitrogen stream to melt-mix. Then, the temperature was raised to 145 ° C. with stirring. Next, while maintaining the temperature at 145 to 146 ° C., 30 parts by weight of the above monomethoxy polyethylene glycol was added to acrylic acid 1
The solution dissolved in 2.9 parts by weight and 1.3 parts by weight of di-t-butylperoxide were separately added dropwise over 1 hour, and then stirring was continued for 1 hour. After cooling, a sodium hydroxide aqueous solution (10% solution) was added while stirring with p
H was added in an amount of about 11 and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 6.

Example 7 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000 and 13.9 parts by weight of fumaric acid, and the mixture was melted by heating under a nitrogen stream. Then, the temperature was raised to 145 ° C. with stirring. Next, while maintaining the temperature at 145 to 146 ° C., 19 parts by weight of acrylic acid and 1.7 parts by weight of di-t-butylperoxide were separately and continuously added dropwise over 1 hour, and then stirring was continued for 1 hour. It was After cooling, aqueous sodium hydroxide solution (10%
The solution) was added with stirring to an amount of about 11 and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 7.

Example 8 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000, heated under a nitrogen stream to melt, and stirred at 150 ° C.
The temperature was raised to. Next, while maintaining the temperature at 150 to 153 ° C., 29.4 parts by weight of acrylic acid and di-t-butylperoxide were added.
Separately, 1.5 parts by weight of oxide was continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling
An aqueous solution of sodium hydroxide (10% solution) in a completely neutralized amount of acrylic acid was added dropwise, and the mixture was heated at reflux temperature with stirring for 1 hour to obtain an aqueous sodium salt solution of graft polymer 8.

Example 9 A reactor similar to that of Example 1 was charged with 70 parts by weight of polyethylene glycol having an average molecular weight of 2000, heated under a nitrogen stream to melt, and heated to 150 ° C. under stirring. . Next, while maintaining the temperature at 150 to 153 ° C., 23.9 parts by weight of acrylic acid and 6.1 parts of n-butyl acrylate were used.
Parts by weight mixed solution, di-t-butylperoxide 1.
5 parts by weight were separately added dropwise continuously over 1 hour,
Then, stirring was continued for 30 minutes. After cooling, a sodium hydroxide aqueous solution (10
% Solution), and the mixture was stirred at room temperature to obtain an aqueous sodium salt solution of the graft polymer 9.

Example 10 A reactor similar to that of Example 1 was charged with 70 parts by weight of polyethylene glycol having an average molecular weight of 200, and the mixture was placed under a nitrogen stream.
The temperature was raised to 150 ° C. with stirring. Next, set the temperature to 150 ~
While maintaining the temperature at 151 ° C., 27.4 parts by weight of acrylic acid and 3 parts by weight of di-t-butylperoxide were separately added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling, a sodium hydroxide aqueous solution (10% solution) in a completely neutralized amount of acrylic acid was added dropwise, and the mixture was heated at reflux temperature with stirring for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 10.

Example 11 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5000 and 16.2 parts by weight of maleic acid, and heated and melt-mixed in a nitrogen stream. Then, the temperature was raised to 150 ° C. with stirring. Next, while maintaining the temperature at 150 to 151 ° C., acrylic acid 21.
Separately, 4 parts by weight and 2.48 parts by weight of di-t-butylperoxide were continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling, an aqueous sodium hydroxide solution (10% solution) was added with stirring in an amount so as to have a pH of about 11, and the mixture was heated at reflux temperature for 1 hour to give a graft polymer 11
An aqueous solution of sodium salt of

Example 12 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000 and 11.8 parts by weight of maleic anhydride, and heated to melt under a nitrogen stream. After mixing, the temperature was raised to 150 ° C. under stirring. Next, while maintaining the temperature at 150 ° C. to 151 ° C., 20.4 parts by weight of acrylic acid, di-t-butylperoxide 1.
6 parts by weight separately, continuously added dropwise over 1 hour,
Then, stirring was continued for 30 minutes. After cooling, a sodium hydroxide aqueous solution (10% solution) was added with stirring in an amount such that the pH was about 11, and the mixture was heated at a reflux temperature for 1 hour to obtain a sodium salt aqueous solution of the graft polymer 12.

Example 13 An aqueous sodium salt solution of the graft polymer 13 was obtained in the same manner as in Example 12 except that the temperature was kept at 140 to 142 ° C.

Example 14 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5000 and 13.9 parts by weight of maleic acid, and melted by heating under a nitrogen stream. The temperature was raised to 140 ° C. with stirring. Next, while keeping the temperature at 140 to 141 ° C., acrylic acid 20.
4 parts by weight and 1.6 parts by weight of di-t-butylperoxide were separately added dropwise continuously over 1 hour, and then 3 parts by weight.
Stirring was continued for 0 minutes. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added with stirring in an amount such that the pH was about 11, and the mixture was heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 14.

Example 15 Monomethoxy polyethylene glycol having an average molecular weight of 5000 was used in place of monomethoxy polyethylene glycol having an average molecular weight of 2000, and the temperature was 140 to 142 ° C.
A sodium salt aqueous solution of the graft polymer 15 was obtained in the same manner as in Example 12 except that the above was maintained.

Example 16 A reactor similar to that of Example 1 was charged with 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5000 and 11.8 parts by weight of maleic anhydride, and heated and melted under a nitrogen stream. After mixing, the temperature was raised to 150 ° C. under stirring. Next, while maintaining the temperature at 150 ° C to 152 ° C, 20.4 parts by weight of acrylic acid, cyclohexaneperoxide 2.
4 parts by weight, separately added dropwise over 1 hour,
Then, stirring was continued for 30 minutes. After cooling, a sodium hydroxide aqueous solution (10% solution) was added with stirring in an amount so that the pH was about 11, and the mixture was heated at a reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 16.

Example 17 In a reactor similar to that of Example 1, 70 parts by weight of polyethylene glycol having an average molecular weight of 3000 and 13.9 parts by weight of maleic acid were charged and heated under a nitrogen stream to melt-mix.
The temperature was raised to 140 ° C. with stirring. Next, set the temperature to 140 ~
While maintaining the temperature at 141 ° C., benzoyl peroxide 1.
A solution prepared by dissolving 4 parts by weight of acrylic acid in 20.4 parts by weight was continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling, aqueous sodium hydroxide solution (10
% Solution) was added with stirring to a pH of about 11 and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 17.

Example 18-In a reactor similar to that of Example 1, 70 parts by weight of ethylene oxide / propylene oxide random copolymer (90/10 molar ratio) having an average molecular weight of 3000, maleic acid 13.
9 parts by weight were charged and heated under a nitrogen stream to melt and mix, and the temperature was raised to 145 ° C. with stirring. Next, set the temperature to 14
While maintaining the temperature at 5 to 147 ° C., 20.4 parts by weight of acrylic acid and 1.6 parts by weight of di-t-butylperoxide were separately added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling, aqueous sodium hydroxide solution (10
% Solution) was added with stirring to a pH of about 11 and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 18.

Example 19 In a reactor similar to that of Example 1, 70 parts by weight of polyethylene glycol having an average molecular weight of 10,000 and succinic anhydride 1.5
Charge 4 parts by weight and raise the temperature to 90 ° C. under a nitrogen stream,
Stir for 1 hour. Next, 13.9 parts by weight of maleic acid was added and melt-mixed, and while maintaining the temperature at 140 to 141 ° C., 20.4 parts by weight of acrylic acid and 1.6 parts by weight of di-t-butylperoxide. Were continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes. After cooling
A sodium hydroxide aqueous solution (10% solution) was added with stirring in an amount so that the pH was about 11, and the mixture was heated at a reflux temperature for 1 hour to obtain a sodium salt aqueous solution of the graft polymer 19.

-Example 20-In place of monomethoxypolyethylene glycol having an average molecular weight of 5000, monomethoxypolyethylene glycol having an average molecular weight of 2000 was used and the temperature was 145 to 146 ° C.
A sodium salt aqueous solution of the graft polymer 20 was obtained in the same manner as in Example 14, except that the acrylic acid and the initiator were continuously added dropwise over 2 hours.

Comparative Example 1 100 parts by weight of polyethylene glycol having an average molecular weight of 3000, 200 parts by weight of water and 1 part of copper (II) sulfate were placed in a glass reactor equipped with a thermometer, a stirrer, a nitrogen introducing tube and a reflux condenser. Charge 0.024 parts by weight of the hydrate and heat to reflux temperature under nitrogen flow, then 125 parts by weight of acrylic acid, 31%
40.3 parts by weight of aqueous hydrogen peroxide solution and 108.33 parts by weight of 48% aqueous sodium hydroxide solution were separately and continuously added dropwise over 2 hours. Then, stirring was continued for 20 minutes at the reflux temperature. After cooling, 48% sodium hydroxide aqueous solution 2
3.44 parts by weight was added to obtain an aqueous sodium salt solution of Comparative Polymer 1.

Comparative Example 2 A glass reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 25 parts by weight of polyethylene glycol having an average molecular weight of 3000 and 50 parts by weight of water, and under a nitrogen stream. , 90 ° C., and then 30 parts by weight of a solution of 1 part by weight of benzoyl peroxide in 25 parts by weight of acrylic acid.
It was dripped continuously over a period of minutes. 90 hours for 2 hours
Stirring was continued at ° C. After cooling, an aqueous solution of sodium hydroxide (10% solution) in a completely neutralized amount of acrylic acid was added dropwise to obtain a sodium salt aqueous solution of Comparative Polymer 2.

Comparative Example 3 A glass reactor equipped with a thermometer, a stirrer, a nitrogen introducing tube, and a reflux condenser was charged with 40 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2000, and the temperature was 90 ° C. under a nitrogen stream. Then, a solution of 0.5 parts by weight of benzoyl peroxide in 10 parts by weight of acrylic acid was continuously added dropwise over 30 minutes. 2 hours later,
Stirring was continued at 90 ° C. After cooling, an aqueous solution of sodium hydroxide (10% solution) in a completely neutralized amount of acrylic acid was added dropwise to obtain an aqueous sodium salt solution of Comparative Polymer 3.

COMPARATIVE EXAMPLE 4 An ethylene oxide / propylene oxide random copolymer (60/4) having an average molecular weight of 3000 was placed in a glass reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser.
(0 mole ratio) 54 parts by weight were charged, and the mixture was heated to 150 ° C. with stirring under a nitrogen stream, and then the above polyether 1
A mixed solution of 1 part by weight and 20 parts by weight of acrylic acid and a mixed solution of 15 parts by weight of the above polyether and 1 part by weight of t-butylperoxy were separately added dropwise continuously for 1 hour and 30 minutes, and then 1 Stirring was continued for hours. After cooling, a sodium hydroxide aqueous solution (10
% Solution), and the mixture was heated at reflux temperature for 1 hour with stirring to obtain a sodium salt aqueous solution of Comparative Polymer 4.

Example 21 The grafting ratio (the amount of the homopolymer not grafted to the polyether) of the polymers obtained in the Examples and Comparative Examples is determined by the solubility of the acid type polymer in benzene. Investigated by. Usually polyacrylic acid, acrylic acid /
Polycarboxylic acids such as maleic acid copolymers are benzene,
It does not dissolve in solvents such as toluene and chloroform.

First, a polymer was prepared as follows.

In Examples 1 to 20 and Comparative Examples 3 and 4, the graft polymers 1 to 20 and the comparative polymers 3 and 4 which had not been neutralized with an aqueous sodium hydroxide solution after the polymerization were used as they were.

The polymer obtained in Comparative Example 1 was treated with a strongly acidic cation exchange resin, sodium carboxylate in acid form was dried, and water was removed to obtain Comparative Polymer 1.

The polymer obtained in Comparative Example 2 was dried to remove water after the polymerization and was neutralized with an aqueous solution of sodium hydroxide to obtain Comparative Polymer 2.

Next, with respect to 10 parts by weight of the prepared polymer,
90 parts by weight of benzene was added, the mixture was heated to the reflux temperature with stirring, and the stirring was continued for 1 hour. After cooling, the state of the benzene solution was visually observed.

Graft polymers 1-20 of Examples 1-20
Was a clear liquid with no turbidity. On the other hand, Comparative Examples 1 to
Comparative polymers 1-4 of 4 had a precipitate. Comparative Examples 1 to 4
In the comparative polymer of (1), many polyacrylic acid homopolymers not grafted to polyether were formed.

-Example 22-Graft polymers 1, 5, 8, 11, and 20 of the above Examples 1, 5, 8, 11, and 20 and Comparative Example 1
The compatibility of the sodium salts of Comparative Polymers 1 to 3 with surfactants was investigated. The compatibility at each temperature of 25 ° C. and 0 ° C. was evaluated as ◯ when uniform and transparent without turbidity, and as × when separated or turbid or opaque. The results are shown in Tables 1 to 3.

The graft polymers of the examples showed excellent compatibility with the surfactant, while the comparative polymers of comparative examples 1 to 3
It was confirmed that the compatibility with the surfactant was as poor as that of sodium polyacrylate, and that many polyacrylic acid homopolymers not grafted to the polyether were formed.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

Reference Examples 1 to 3 (Evaluation of Water-Soluble Graft Polymer Obtained by the Production Method of the Present Invention as Dispersant) The graft polymer of Example 1 and Comparative Polymer 1 of Comparative Examples 1 and 4 above. 4 was evaluated as a dispersant.

Light calcium carbonate (Brilliant # 15
00: product name of Shiraishi Industry Co., Ltd.) / Water = 60/40
The viscosity of the slurry prepared by adding the graft polymer and the comparative polymer to the slurry adjusted to have a (weight ratio) and stirring the mixture was measured by a B-type rotational viscosity system and shown in units of centipoise. When the graft polymer was not added, the slurry had almost no fluidity and the viscosity could not be measured. The results are shown in Table 4. The graft polymer of the example exhibited better performance as a dispersant than the comparative polymer of the comparative example, and the viscosity of the calcium carbonate slurry was reduced with a low addition amount.

[0063]

[Table 4]

-Reference Examples 4 to 7- (Evaluation of Water-Soluble Graft Polymer Obtained by the Production Method of the Present Invention as a Water Treatment Agent) Examples 5, 13 and 20 above
Using the graft polymer of Comparative Example 4 and Comparative Polymer 4 of Comparative Example 4 as a water treatment agent, the scale prevention performance was evaluated.

170 g of water in a glass bottle of 225 ml capacity
Add 1.56% calcium chloride dihydrate aqueous solution 10
g, and 0.02% of the graft polymer of the above example
3 g of the aqueous solution was mixed, and further 10 g of a 3% sodium bicarbonate aqueous solution and 7 g of water were added to make the total amount 200 g.
The resulting supersaturated aqueous solution of calcium carbonate (530 ppm) was sealed and heat-treated at 70 ° C. for 3 hours. After cooling
The precipitate was filtered through a membrane filter having a pore size of 0.1 μm, the filtrate was analyzed according to JIS K0101, and the calcium carbonate inhibition rate (%) was determined by the following formula. The results are shown in Table 5.
It was shown to.

Scale inhibition rate (%) = (CB) / (A
-B) x 100 A: Calcium concentration dissolved in the liquid before the test B: Calcium concentration in the filtrate tested without adding a scale inhibitor C: Calcium concentration in the filtrate after the test Example The graft polymer of No. 3 showed better performance as a water treatment agent than the comparative polymer of Comparative Example.

[0067]

[Table 5]

Reference Example 8 (Evaluation of Water-Absorbent Resin Formed by Crosslinking Water-Soluble Graft Polymer Obtained by the Production Method of the Present Invention) In the same reactor as in Example 1, polyethylene glycol 70 having an average molecular weight of 7,500 was used. Part by weight was charged and heated under a nitrogen stream to melt, and the temperature was raised to 150 ° C. with stirring. Then set the temperature to 15
While maintaining the temperature at 0 to 152 ° C., 26.5 parts by weight of acrylic acid and 0.6 parts by weight of t-butylperoxide were separately added,
The solution was continuously added dropwise over 1 hour, and then stirring was continued for 30 minutes to obtain a graft polymer. To 13.7 parts by weight of the obtained graft polymer, 4.8 parts by weight of a 48% sodium hydroxide aqueous solution and 12 parts by weight of water were added, and the mixture was heated to the reflux temperature with stirring and uniformly dissolved. , Polyethylene glycol diglycidyl ether (Denacol EX-
830: 0.8 part by weight of Nagase Kasei Kogyo Co., Ltd.) was added and heated at 90 ° C. for 4 hours to obtain a gel. Next, the obtained gel was dried under reduced pressure at 90 ° C. for 12 hours and pulverized to obtain a water absorbent resin.

When the water absorption capacity of the water absorbent resin was measured,
Pure water was 104 times, physiological saline was 34 times, and seawater was 20 times, showing high salt resistance.

[0070]

According to the method for producing a water-soluble graft polymer of the present invention, a polyether containing ethylene oxide as a main component and a monoethylenically unsaturated monomer mainly containing (meth) acrylic acid as a carboxylic acid A water-soluble graft polymer having a high acid density and a high graft efficiency, in other words, a small amount of a polymer of a monoethylenically unsaturated monomer not grafted on a polyether, can be easily and efficiently produced.

Claims (2)

[Claims] 1. A (meth) acrylic acid (b1) 40 is added to a polyether compound (A) having a number average molecular weight of 200 or more and having 80 mol% or more of ethylene oxide as a constitutional unit.
˜100 mol% and a copolymerizable other monoethylenically unsaturated monomer (b2) 0 to 60 mol% of the monomer component (B) to the polyether compound (A) 25 w
When a water-soluble graft polymer is obtained by graft polymerization in an amount of t% or more, the monomer component (B) is added to the polyether compound (A) in the presence of a polymerization initiator and substantially no solvent is used.
A method for producing a water-soluble graft polymer, which comprises carrying out a graft polymerization reaction at a temperature of 100 ° C. or higher. 2. At least one selected from the group consisting of maleic acid, fumaric acid and maleic anhydride as the monomer component (b2).
One monomer is used, and half or more of the amount of the monomer component (b2) used is mixed in advance with the polyether compound, and then the rest of the monomer component (B) and the polymerization initiator are added to perform grafting. The method for producing a water-soluble graft polymer according to claim 1, wherein the polymerization is performed.