JP2945822B2 - Method for producing water-soluble graft polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Attempts to graft polymerize (meth) acrylic acid to polyether compounds have been made in various fields of application such as polyurethane. For example, JP
Japanese Patent Application Laid-Open No. 5-71710 discloses that 3 to 15 w
A polymer in which t% of acrylic acid is graft-polymerized to 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 the carboxylic acid is too small, so that satisfactory performance is not obtained or to obtain performance. Requires a very large amount of addition.

JP-A-59-62614 discloses that at least 20% by weight of a polyglycol ether having at least one hydrophobic group is based on a graft polymer.
In the graft polymer obtained by graft polymerization of the above hydrophilic ethylenically unsaturated monomer and a 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 even without a solvent is disclosed. I have. The graft 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 builder or a dispersant such as an inorganic pigment, satisfactory performance cannot be obtained, and when used as a builder for a liquid detergent, there is a problem that the polymer is separated.

Further, Japanese Patent Application Laid-Open No. 3-177406 discloses a similar graft polymer obtained by polymerization in an aqueous solvent. However, the disclosed polymerization method of graft polymerization in an aqueous solvent has poor grafting efficiency, and many of the resulting polymers are ungrafted polycarboxylic acids. There is a problem that it cannot be obtained.

As described above, according to the conventional technique, a graft polymer having a high carboxylic acid density and a high graft efficiency and having a small amount of ungrafted polymer could not be easily produced.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to 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 with a high content and has a high graft ratio.

[0007]

Means for Solving the Problems The present inventors have solved the above-mentioned problems, and as a result of intensive studies on 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.

According to the present invention, ethylene oxide is used in an amount of 80 mol.
The polyether compound (A) having a number average molecular weight of 200 or more having a structural unit of 1% or more is added with 40 to 100 mol% of (meth) acrylic acid (b1) and another copolymerizable monoethylenically unsaturated monomer ( b2) A monomer component (B) consisting of 0 to 60 mol% is converted to a polyether compound (A)
To obtain a water-soluble graft polymer by graft polymerization in an amount of 25% by weight or more based on the monomer component (B) with the polyether compound (A) in the presence of a polymerization initiator. A production method characterized by performing a graft polymerization reaction at a temperature of 100 ° C. or higher without using the same.

The polyether compound (A) used in the present invention has a number average molecular weight of 200 or more having ethylene oxide as a constitutional unit in an amount of 80 mol% or more. It is obtained by polymerizing in a known manner as a starting point. Examples of the alcohol for obtaining the polyether include alcohols having 1 to 1 carbon atoms such as methanol, ethanol, n-propanol, and n-butanol.
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, and propylene glycol;
Examples thereof include triols such as glycerin and trimethylolpropane; and polyols such as sorbitol. Other alkylene oxides that can be copolymerized with ethylene oxide include, but are not particularly limited to, propylene oxide,
Butylene oxide is preferred. Further, the content of other alkylene oxides copolymerizable with ethylene oxide needs to be less than 20 mol% as a whole. 20mol
% Or more, the graft ratio of the obtained graft polymer decreases. Further, as the polyether compound (A), the hydroxyl groups at all or some of the terminals of the polyether obtained as described above may be substituted with fatty acids having 2 to 22 carbon atoms, 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
00 or more, preferably 500 or more, more preferably 1000 or more. Although 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, 6000 or less is preferred.
When the molecular weight is smaller than 200, there is a problem that the amount of ungrafted polyether increases.

In the present invention, the polyether compound (A)
(Meth) acrylic acid (b1) 40 to 100 mol%,
And a monomer component (B) composed of 0 to 60 mol% of another copolymerizable monoethylenically unsaturated monomer (b2),
25 w / 100 wt% polyether compound (A)
It is necessary to perform graft polymerization of t% or more. More preferably, acrylic acid as the component (b1) in the monomer component (B) is graft-polymerized in an amount of 20% by weight or more based on 100% by weight of the polyether compound (A). When the amount is less than 25 wt%, the carboxylic acid density of the obtained graft polymer is low, 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 Alkyl esters of maleic acid such as dimethyl fumarate and diethyl fumarate; alkyl esters of fumaric acid such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, stearyl (meth) acrylate Alkyl (meth) acrylates; hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; alkenyl acetates such as vinyl acetate; aromatic vinyls such as styrene; (meth) acrylonitrile;
(Meth) acrolein, (meth) acrylamide; dialkylaminoethyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; 2-acrylamido-2-methylpropanesulfonic acid; and one or two of these. More than one species can be used. Among these, maleic acid, fumaric acid, and maleic anhydride are preferred from the viewpoint of increasing the carboxylic acid density of the graft polymer and increasing the polyvalent metal ion chelating ability and dispersing ability.

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

The copolymerization ratio of (meth) acrylic acid (b1) and another copolymerizable monoethylenically unsaturated monomer (b2) is (b1) 40 to 100 mol% and (b2) is 0 ~ 60
mol%. When the monomer (b2) is a monomer having no carboxyl group, the copolymerization ratio is such that (b1) is 80%.
-100 mol%, and the monomer (b2) is preferably 0-20 mol%. When the monomer (b2) is a monomer having no carboxyl group, (meth) acrylic acid is 80 mol%
If the amount is smaller, the carboxylic acid density of the obtained graft polymer is low, and the performance such as polyvalent metal ion chelating ability and dispersing ability is not satisfied. In the case where (b2) is a carboxyl group-containing monomer such as maleic acid, fumaric acid, or maleic anhydride, even if the amount of (meth) acrylic acid is less than 40 mol%, the carboxylic acid density of the obtained graft polymer is reduced. In this case, (meth) acrylic acid is 40m
When the amount is less than ol%, there is a problem that the rate of introduction of maleic acid, fumaric acid, maleic anhydride or the like into the graft polymer decreases, and the amount of remaining monomer increases.

The graft polymerization is carried out in the presence of a polymerization initiator.
This is performed substantially without using a solvent.

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

Examples of the organic peroxide include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, , 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 Peroxyesters such as di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyisopropylcarbonate; n-butyl-4,4 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 is preferably 0.1 to 0.1 based on the monoethylenically unsaturated monomer.
It is used in an amount of 15% by weight, more preferably 0.5 to 10% by weight. If the amount is smaller or larger, the grafting efficiency of the monomer to the polyether decreases. Also, the polymerization initiator can be added to the polyether in advance,
It can be added simultaneously with the monoethylenically unsaturated monomer.

The graft polymerization is carried out substantially without a solvent. When water or an organic solvent such as alcohol or toluene is used, the grafting efficiency of the monomer onto the polyether decreases. When a solvent is used for the addition of the initiator and the monomer, its amount is minimized, preferably 5 w
It is preferable that the content is adjusted to t% or less, or it is distilled off from the reaction system immediately after the addition.

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

At the time of the graft polymerization, it is preferable to initially or partially charge the polyether compound (A). When maleic acid, fumaric acid or maleic anhydride is used for the monomer (b2), it is preferable to initially charge at least half of the amount of the monomer (b2) used together with the polyether compound (A). . Then, the remaining monomer and the initiator are separately dropped 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) can be mixed with an initiator or a monomer and dropped.

The obtained polymer can be used as it is as a dispersant or scale inhibitor by dissolving it in a solvent such as water or alcohol, or by adding a base. Examples of the base include, for example, monovalent metal salts such as sodium salts and potassium salts, divalent metal salts such as calcium salts, trivalent metal salts such as aluminum salts, and the like, and organic amine salts such as ammonium salts, 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 an inorganic or organic substance which is hardly soluble in water. 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 slurries such as cement and coal. In addition, it is also used for cooling water system, boiler water system, seawater desalination equipment, water treatment agent for scale prevention in pulp digester, black liquor concentration kettle, fiber treatment agent such as dyeing assistant and fiber antistatic assistant. can do.

Further, the water-soluble graft polymer obtained by the production method of the present invention can be used as a water-absorbing 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 grafting ratio, the water-absorbent resin obtained by crosslinking with a crosslinking agent has a low soluble content, and also contains a polyether in its main chain, so that it has salt resistance. Water-absorbent resin having a high water content is obtained. The crosslinking is carried out by a known method and is not particularly limited, but is preferably carried out by a reaction between a carboxylic acid of the graft polymer and a 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 and melted under a nitrogen stream to stir. 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-butyl peroxide were separately dropped continuously over 1 hour, and then stirring was continued for 20 minutes. Was. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added dropwise to the neutralized amount of acrylic acid, and the mixture was heated at reflux for 1 hour with stirring to obtain an aqueous sodium salt of graft polymer 1.

Example 2 A reactor similar to that of Example 1 was charged with 100 parts by weight of monomethoxy polyethylene glycol having an average molecular weight of 2,000, heated and melted under a nitrogen stream, and stirred at 130 ° C.
Temperature. 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-butyl peroxide were separately dropped continuously over one hour, and thereafter, stirring was continued for 80 minutes. After cooling, sodium hydroxide aqueous solution (10
% Solution), and the mixture was heated at reflux for 1 hour with stirring to obtain an aqueous sodium salt solution of the graft polymer 2.

Example 3 70 parts by weight of polyethylene glycol having an average molecular weight of 2,000 were charged into the same reactor as in Example 1, heated and melted under a nitrogen stream, and heated to 145 ° C. with stirring. . Next, while maintaining the temperature at 146 to 147 ° C., 30 parts by weight of acrylic acid and 0.1% of di-t-butyl peroxide were added.
3 parts by weight separately and continuously dropped over 1 hour,
Thereafter, stirring was continued for 1 hour. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added dropwise to the acrylic acid to completely neutralize acrylic acid, and the mixture was heated at reflux for 1 hour with stirring to obtain an aqueous solution of a sodium salt of the 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 and melted under a nitrogen stream, and heated to 150 ° C. with 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-butyl peroxide were separately dropped continuously over one hour, and thereafter, stirring was continued for 30 minutes. Was. After cooling, a sodium hydroxide aqueous solution (1
0% solution) and heated at reflux 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 monomethoxy polyethylene glycol having an average molecular weight of 2,000 and 13.9 parts of maleic acid, and heated and melted and mixed under a nitrogen stream. 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-butyl peroxide were separately dropped continuously over one hour, and thereafter, stirring was continued for one hour. Was. After cooling, aqueous sodium hydroxide solution (10%
The solution) was added to an amount of about pH 11 with stirring, and heated at reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 5.

Example 6 40 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2,000 and 20.9 parts by weight of maleic acid were charged into the same reactor as in Example 1, and the mixture was heated and melt-mixed under a nitrogen stream. The mixture was heated to 145 ° C. under 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
A solution dissolved in 2.9 parts by weight and 1.3 parts by weight of di-t-butyl peroxide were separately dropped continuously over 1 hour, and thereafter, stirring was continued for 1 hour. After cooling, an aqueous sodium hydroxide solution (10% solution) was added while stirring.
H was added to an amount of about 11, and the mixture was heated at the reflux temperature for 1 hour to obtain an aqueous sodium salt solution of the graft polymer 6.

Example 7 70 parts by weight of monomethoxy polyethylene glycol having an average molecular weight of 2000 and 13.9 parts by weight of fumaric acid were charged into the same reactor as in Example 1, and heated and melted and mixed under a nitrogen stream. The mixture was heated to 145 ° C. under 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-butyl peroxide were separately dropped continuously over 1 hour, and thereafter, stirring was continued for 1 hour. Was. After cooling, aqueous sodium hydroxide solution (10%
The solution) was added to an amount of about pH 11 with stirring, 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 monomethoxy polyethylene glycol having an average molecular weight of 2,000, heated and melted under a nitrogen stream, and stirred at 150 ° C.
Temperature. Next, while maintaining the temperature at 150 to 153 ° C, 29.4 parts by weight of acrylic acid and di-t-butyl
1.5 parts by weight of oxide was separately added dropwise continuously over 1 hour, and then stirring was continued for 30 minutes. After cooling,
An aqueous sodium hydroxide solution (10% solution) of the amount of the acrylic acid that was added dropwise was added, and the mixture was heated at reflux for 1 hour with stirring to obtain an aqueous sodium salt of the 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 2,000, heated and melted in a nitrogen stream, and heated to 150 ° C. with 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.
1 part by weight of the mixed solution, di-t-butyl peroxide
5 parts by weight separately and continuously dropped over 1 hour,
Thereafter, stirring was continued for 30 minutes. After cooling, a 90% neutralized amount of sodium hydroxide aqueous solution of acrylic acid (10%) was added dropwise.
% Solution) and stirred at room temperature to obtain an aqueous solution of a sodium salt 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 then charged under a nitrogen stream.
The temperature was raised to 150 ° C. under stirring. Next, raise 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-butyl peroxide were separately dropped continuously over 1 hour, and thereafter, stirring was continued for 30 minutes. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added dropwise to the neutralized amount of acrylic acid, and the mixture was heated at reflux for 1 hour with stirring to obtain an aqueous solution of a sodium salt of the graft polymer 10.

Example 11 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5,000 and 16.2 parts by weight of maleic acid were charged into the same reactor as in Example 1, and the mixture was heated and melted and mixed under a nitrogen stream. The temperature was raised to 150 ° C. under stirring. Next, while maintaining the temperature at 150 to 151 ° C., acrylic acid 21.
4 parts by weight and 2.48 parts by weight of di-t-butyl peroxide were separately added dropwise continuously over 1 hour, and then stirring was continued for 30 minutes. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added to the mixture so as to have a pH of about 11 with stirring, and the mixture was heated at a reflux temperature for 1 hour to obtain a graft polymer 11
To obtain an aqueous sodium salt solution.

Example 12 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 2,000 and 11.8 parts by weight of maleic anhydride were charged into a reactor similar to that of Example 1, and heated and melted under a stream of nitrogen. The mixture was mixed and heated to 150 ° C. with stirring. Next, while keeping the temperature at 150 ° C. to 151 ° C., 20.4 parts by weight of acrylic acid and di-t-butyl peroxide.
6 parts by weight separately and continuously dropped over 1 hour,
Thereafter, stirring was continued for 30 minutes. After cooling, an aqueous solution of sodium hydroxide (a 10% solution) was added to the mixture so as to have a pH of about 11 with stirring, and the mixture was heated at a reflux temperature for 1 hour to obtain an aqueous solution of a sodium salt 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 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5000 and 13.9 parts by weight of maleic acid were charged into a reactor similar to that of Example 1, and heated and melted and mixed in a nitrogen stream. The temperature was raised to 140 ° C. under stirring. Next, while maintaining the temperature at 140 to 141 ° C, acrylic acid 20.
4 parts by weight and 1.6 parts by weight of di-tert-butyl peroxide were separately added dropwise continuously over 1 hour.
Stirring was continued for 0 minutes. After cooling, an aqueous solution of sodium hydroxide (a 10% solution) was added while stirring to reach a pH of about 11 and heated at reflux for 1 hour to obtain an aqueous solution of a sodium salt of the graft polymer 14.

EXAMPLE 15 Monomethoxy polyethylene glycol having an average molecular weight of 5,000 was used in place of monomethoxy polyethylene glycol having an average molecular weight of 2,000, and the temperature was 140 to 142 ° C.
In the same manner as in Example 12, except that the temperature was kept at, an aqueous sodium salt solution of the graft polymer 15 was obtained.

Example 16 70 parts by weight of monomethoxypolyethylene glycol having an average molecular weight of 5,000 and 11.8 parts by weight of maleic anhydride were charged into the same reactor as in Example 1, and heated and melted under a nitrogen stream. The mixture was mixed and heated to 150 ° C. with stirring. Next, while maintaining the temperature at 150 ° C. to 152 ° C., 20.4 parts by weight of acrylic acid and cyclohexane peroxide
4 parts by weight separately and continuously dropped over 1 hour,
Thereafter, stirring was continued for 30 minutes. After cooling, an aqueous solution of sodium hydroxide (a 10% solution) was added while stirring to reach a pH of about 11 and heated at reflux for 1 hour to obtain an aqueous solution of a sodium salt of the graft polymer 16.

Example 17 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 and 13.9 parts by weight of maleic acid, and heated and melted and mixed under a nitrogen stream.
The temperature was raised to 140 ° C. under stirring. Next, raise the temperature to 140-
While maintaining at 141 ° C., benzoyl peroxide 1.
A solution in which 4 parts by weight of acrylic acid was dissolved in 20.4 parts by weight of acrylic acid 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 thereto while stirring, and the mixture was heated at reflux temperature for 1 hour to obtain a sodium salt aqueous solution of the graft polymer 17.

Example 18 In a reactor similar to that of Example 1, 70 parts by weight of an ethylene oxide / propylene oxide random copolymer (average molecular weight: 3000) (90/10 molar ratio), maleic acid 13.
9 parts by weight were charged, heated and melt-mixed under a nitrogen stream, and heated to 145 ° C. with stirring. Next, raise 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-butyl peroxide were separately dropped continuously over 1 hour, and thereafter, stirring was continued for 30 minutes. After cooling, aqueous sodium hydroxide solution (10
% Solution) was added thereto while stirring, and the mixture was heated at the reflux temperature for 1 hour to obtain a sodium salt aqueous 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 were added.
4 parts by weight, and heated 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. The temperature was raised 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-butyl peroxide. 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) was added while stirring to reach a pH of about 11 and heated at reflux for 1 hour to obtain an aqueous solution of a sodium salt of the graft polymer 19.

Example 20 Monomethoxy polyethylene glycol having an average molecular weight of 2,000 was used in place of monomethoxy polyethylene glycol having an average molecular weight of 5,000, and the temperature was 145 to 146 ° C.
, And an aqueous sodium salt solution of the graft polymer 20 was obtained in the same manner as in Example 14 except that acrylic acid and the initiator were continuously dropped over 2 hours.

Comparative 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, 200 parts by weight of water, and copper (II) sulfate. 0.024 parts by weight of the hydrate was charged and heated to the reflux temperature under a stream of nitrogen, and then 125 parts by weight of acrylic acid, 31%
40.3 parts by weight of an aqueous solution of hydrogen peroxide and 108.33 parts by weight of an aqueous solution of 48% sodium hydroxide were continuously dropped separately over 2 hours. After that, stirring was continued at the reflux temperature for 20 minutes. After cooling, 48% aqueous sodium hydroxide solution 2
By adding 3.44 parts by weight, an aqueous solution of sodium salt of Comparative Polymer 1 was obtained.

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

Comparative Example 3 A glass reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser was charged with 40 parts by weight of monomethoxy polyethylene glycol having an average molecular weight of 2,000, and heated at 90 ° C. under a nitrogen stream. Then, a solution of 0.5 parts by weight of benzoyl peroxide dissolved in 10 parts by weight of acrylic acid was continuously dropped over 30 minutes. Then for 2 hours,
Stirring was continued at 90 ° C. After cooling, an aqueous solution of sodium hydroxide (10% solution) was added dropwise in a completely neutralized amount of acrylic acid to obtain an aqueous solution of sodium salt of Comparative Polymer 3.

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

Example 21 The graft ratio (the amount of the homopolymer not grafted to the polyether) of the polymers obtained in Examples and Comparative Examples is determined by examining the solubility of the acid type polymer in benzene. Investigated by. Usually polyacrylic acid, acrylic acid /
Polycarboxylic acids such as maleic acid copolymer include benzene,
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, graft polymers 1 to 20 and comparative polymers 3 and 4 before polymerization and before neutralization with an aqueous sodium hydroxide solution were used as they were.

The polymer obtained in Comparative Example 1 was treated with a strongly acidic cation exchange resin, the sodium carboxylate was converted to an acid form, and the resulting product was dried to remove water. Thus, Comparative Polymer 1 was obtained.

The polymer obtained in Comparative Example 2 was dried before the solution was neutralized with an aqueous solution of sodium hydroxide after polymerization, and water was removed 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 stirring was continued for 1 hour. After cooling, the appearance of the benzene solution was visually observed.

Graft polymers 1 to 20 of Examples 1 to 20
Was a clear liquid without turbidity. On the other hand, Comparative Examples 1 to
The comparative polymers 1 to 4 of 4 had a precipitate. Comparative Examples 1-4
In Comparative Polymer No., a large amount of polyacrylic acid homopolymer not grafted to polyether was formed.

-Example 22-Sodium salt of the graft polymer 1, 5, 8, 11, 20 of Examples 1, 5, 8, 11, and 20 and Comparative Example 1
The compatibility of the sodium salts of Comparative Polymers 1 to 3 with a surfactant was examined. The compatibility at each temperature of 25 ° C. and 0 ° C. was evaluated as ○ when uniform, turbid and transparent, and X when separated, turbid or opaque. The results are shown in Tables 1 to 3.

Although the graft polymers of the examples exhibited excellent compatibility with the surfactant, the comparative polymers of Comparative Examples 1 to 3
The compatibility with the surfactant was poor as in the case of sodium polyacrylate, and it was confirmed 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) Graft polymer of Example 1 and Comparative polymer 1 of Comparative Examples 1 and 4 And 4 were evaluated as dispersants.

Light calcium carbonate (Brilliant # 15)
00: trade name manufactured by Shiraishi Industry Co., Ltd.) / Water = 60/40
The graft polymer and the comparative polymer were added to the slurry adjusted to be (weight ratio), and the viscosity of the slurry adjusted by stirring was measured by a B-type rotational viscosity system, and was indicated in 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 small amount of addition.

[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) The above Examples 5, 13, and 20
Using the graft polymer of Comparative Example 4 and Comparative Polymer 4 of Comparative Example 4 as water treatment agents, the scale prevention performance was evaluated.

170 g of water in a 225 ml glass bottle
And 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 10 g of a 3% aqueous sodium bicarbonate solution and 7 g of water were further added to make the total amount 200 g.
The obtained 530 ppm supersaturated aqueous solution of calcium carbonate was sealed and heated at 70 ° C. for 3 hours. After cooling,
The precipitate was filtered with a membrane filter having a pore size of 0.1 μm, and the filtrate was analyzed in accordance with JIS K0101. The calcium carbonate inhibition rate (%) was determined by the following equation. Table 5 shows the results
It was shown to.

Scale inhibition rate (%) = (CB) / (A
-B) × 100 A: The concentration of calcium dissolved in the liquid before the test B: The concentration of calcium in the filtrate, which was tested without the addition of a scale inhibitor C: The concentration of calcium in the filtrate after the test The graft polymer of (1) showed better performance as a water treatment agent than the comparative polymer of Comparative Example.

[0067]

[Table 5]

-Reference Example 8- (Evaluation of a water-absorbent resin obtained by crosslinking a water-soluble graft polymer obtained by the production method of the present invention) In a reactor similar to that in Example 1, polyethylene glycol 70 having an average molecular weight of 7,500 was used. A part by weight was charged, heated and melted under a nitrogen stream, and heated to 150 ° C. with stirring. Next, 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 part by weight of t-butyl peroxide were separately added.
The solution was continuously dropped for one hour, and thereafter, 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% aqueous sodium hydroxide solution and 12 parts by weight of water were added, and the mixture was heated to the reflux temperature with stirring to dissolve uniformly. , 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-absorbing resin.

When the water absorption capacity of the water-absorbent resin was measured,
The ratio was 104 times with pure water, 34 times with physiological saline, and 20 times with seawater, indicating high salt resistance.

[0070]

According to the method for producing a water-soluble graft polymer of the present invention, a monoethylenically unsaturated monomer mainly composed of (meth) acrylic acid is added to a polyether mainly composed of ethylene oxide. It is possible to easily and efficiently produce a water-soluble graft polymer having a high acid density and a high grafting efficiency, in other words, having a small amount of a polymer of a monoethylenically unsaturated monomer not grafted to a polyether.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-211949 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F 283/06

Claims (1)

(57) [Claims] 1. A polyether compound (A) having a number average molecular weight of 200 or more having ethylene oxide as a constitutional unit in an amount of 80 mol% or more is added with (meth) acrylic acid (b1) 40 to
A monomer component (B) consisting of 100 mol% and 0 to 60 mol% of another copolymerizable monoethylenically unsaturated monomer (b2) is added at 25 wt% to the polyether compound (A).
In obtaining the water-soluble graft polymer by graft polymerization in the above amount, the monomer component (B) is added to the polyether compound (A) in the presence of a polymerization initiator substantially without using a solvent,
A method of performing a graft polymerization reaction at a temperature of 100 ° C. or more.
Thus, as the other monomer (b2), maleic acid, fumaric acid,
At least one monomer selected from the group of water maleic acid
Using at least half of the amount of monomer (b2) used in advance, the polyether
After mixing with compound (A), the remaining monomer component (B)
And a method for producing a water-soluble graft polymer, which comprises adding the polymerization initiator and performing graft polymerization.