JPS6220502A - Production of water-soluble polymer dispersion - Google Patents

Abstract

PURPOSE:To obtain at low cost the titled low-viscosity and free-flowing dispersion useful as flocculant for wastewater treatment, papermaking chemicals, etc., by polymerization of a water-soluble monomer while stirring in an aqueous salt solution in the presence of polyhydric alcohol. CONSTITUTION:The objective dispersion can be obtained by polymerization of a water-soluble acrylic monomer on stirring, in an aqueous salt solution (e.g., of Na2SO4, NaCl) while separating the polymer formed, in the presence of, normally >=0.1wt%, based on said solution, of a polyhydric alcohol (e.g., ethylene glycol, glycerin, polypropylene glycol with a molecular weight <=600). Said water-soluble monomer is pref. a mixture of <=15mol% of (meth)acrylic acid alkali metal salt and (meth)acrylamide.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is widely applicable to flocculants and dehydrating agents for wastewater treatment, papermaking agents used in papermaking processes, dispersion stabilizers for various suspension solutions, soil conditioners, etc. (Regarding a new method for producing water-soluble polymers.

(Prior art) Conventionally, methods for producing water-soluble polymers as described above include stationary polymerization in an aqueous solution, water-in-oil emulsion polymerization (Japanese Patent Application Laid-open No. 102388-1988), and hydrophobic solvents. suspension polymerization (Japanese Unexamined Patent Publication No. 54-69196).

Also, as precipitation polymerization in a salt aqueous solution, JP-A-50-70
No. 489 has been disclosed in Japanese Patent Publication No. 46-1490 as polymerization in an aqueous salt solution containing acrylic acid as the main component at low pH.
7 are disclosed.

(Objective of the invention and problems to be solved) In the aqueous solution stationary polymerization method, in order to obtain a high molecular weight polymer, 1
Since polymerization is carried out at a monomer concentration of 0% or more, the product becomes a water-containing glue and is difficult to dissolve as it is, so it is either diluted further and sold as a fluid low concentration solution, or dried. It needs to be powdered. When commercially available at a low concentration, transportation costs are high, and when powdered, a large amount of thermal energy is required for drying, and three-dimensional crosslinking occurs due to heating, resulting in the formation of water-insoluble parts. It has the disadvantage of causing

Water-in-oil emulsions are flammable and have the disadvantage of wasting valuable organic solvents, while suspension polymerization in hydrophobic solvents produces flammable substances such as cyclohexane and toluene. This method has the disadvantage that a large amount of money is required for manufacturing equipment.

Precipitation polymerization in an aqueous salt solution is a good method because it requires low equipment costs, but it has the disadvantage that the polymers produced adhere to each other and form large lumps, making handling extremely difficult. Furthermore, in the method disclosed in Japanese Patent Publication No. 46-14907, it is possible to use only unneutralized acrylic acid, but it has not been successful with neutralized acrylic acid such as sodium salt.

The present invention aims to eliminate the above-mentioned drawbacks.

(Means for Solving the Problems) The present inventors have made efforts to overcome these drawbacks and to produce a water-soluble polymer dispersion that has good fluidity and is easy to handle using low-cost production equipment. As a result of research, we have arrived at the present invention. The present inventors have previously filed an application (Japanese Patent Application No. 59-244152) regarding the polymerization of a cationic monomer in which a benzyl group is bonded to an amine group in an aqueous salt solution.
It has been found that a similar polymerization method can be applied to the polymerization of water-soluble acrylic monomers in the coexistence of polyhydric alcohols, and the present invention has been achieved.

That is, the present invention provides a free-flowing solution characterized in that polyhydric alcohols are allowed to coexist when polymerizing the acrylic water-soluble monomer (A) while precipitating the polymer in a salt aqueous solution with stirring. The present invention relates to a method for producing a water-soluble polymer dispersion. Examples of the acrylic water-soluble monomer (A) include (meth)acrylamide, N,N-dimethylacrylamide, alkali metal salts of (meth)acrylic acid, alkali metal salts of 2-acrylamide-2-methylsulfonic acid, Examples include cationic monomers represented by the following formulas (I) and (It).

] One or a combination of two or more of the above monomers can be selected, but as stated in claim 1, since the polymerization is carried out while precipitating the polymer,
The condition is that the resulting polymer of monomer (A) is not dissolved in the salt aqueous solution. Regarding nonionic monomers such as acrylamide, the present invention can be carried out by homopolymerization, but the formula (
With respect to ionic monomers other than the monomer I), homopolymerization is impossible because the polymer dissolves in the salt aqueous solution.

Therefore, the ionic monomer not containing formula (I) is preferably copolymerized with a nonionic monomer such as acrylamide, and the amount thereof is preferably 15 mol or less.

Regarding the cationic monomer of formula (I), a strongly hydrophobic benzyl group is bonded to the amino group, and as a result, the formula (
Monomer I), even in the form of a homopolymer, does not dissolve in an aqueous salt solution and can be used in a wide range of proportions.

Furthermore, since the present invention relates to a method for producing a water-soluble polymer, it is limited to the combinations of monomers listed above as long as the polymer of the water-soluble monomer (A) is water-soluble. It's not a thing. For example, monomers having a certain degree of solubility in water, such as acrylonitrile, can also be used as long as the copolymer with the water-soluble monomer (A) is water-soluble.

Regarding the aqueous salt solution used in the present invention as a dispersion medium for polymerization, the condition is that the polymerization product does not dissolve therein. Typical salts include sodium sulfate, ammonium sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, sodium dihydrogen phosphate, ammonium hydrogen phosphate, dipotassium hydrogen phosphate, or two or more of these salts. Examples include mixtures of Salts other than these are within the scope of the present invention as long as they do not dissolve the polymerization product.

The concentration of the aqueous salt solution varies depending on the molar ratio of the ionic monomers and the salt used and is not particularly limited, but is generally preferably 15% by weight or more, up to the limit of solubility. Also,
It is also possible to further reduce the viscosity of the dispersion by adding a salt within the solubility range to the dispersion after polymerization.

Polyhydric alcohols coexisting during polymerization include ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitol, and alcohols with a molecular weight of 600.
Examples include the following polyethylene glycol, polypropylene glycol, etc., but are not particularly limited.

The amount of polyhydric alcohol is preferably 0.1% by weight or more based on the aqueous salt solution, and if it is less than 0.1%, the resulting polymer will not be obtained in a dispersed state and will adhere to each other and form large lumps, which is undesirable. .

Next, regarding the polymerization method, details will be described in Examples, but the outline thereof is as follows.

A predetermined water-soluble acrylic monomer (A) is added to an aqueous salt solution in which polyhydric alcohols are dissolved, and after deoxidizing with nitrogen gas, a polymerization initiator is added and polymerization is initiated while stirring. Upon completion of the polymerization, polymer particles having a particle size of about 1 mm or less are obtained in a dispersed state. The monomer concentration at this time is ioo of the salt aqueous solution.
Any amount of 5 parts by weight or more may be used, and if it is less than 5 parts by weight, there is no advantage in aqueous solution polymerization. Further, the upper limit can be up to the amount at which the product no longer has fluidity. The polymerization temperature varies depending on the type of polymerization initiator, and is not particularly limited as long as it is a temperature at which the initiator functions.

Further, the polymerization initiator is not limited and may be any commonly used redox type or azo type.

(Function) The feature of the present invention is that water-soluble monomers are polymerized in a salt aqueous solution in the coexistence of polyhydric alcohols with stirring.

At this time, the aqueous salt solution is there to prevent the polymer produced from dissolving, and the polyhydric alcohols that coexist with it, although their effects are not fully understood, act as protective colloids and adhere to the produced polymer. It is thought that this prevents this and contributes to the stabilization of the dispersion.

(Examples) Next, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 1t equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube
Five-neck separable flask, acrylamide 75
gI, 106.3 f of ammonium sulfate, 7.5 y of ethylene glycol, and 311.22 g of ion-exchanged water were charged, heated to 45°C, and replaced with nitrogen.

To this, 2.37 g of 2-2'-azobis(2-amidinopropane) hydrochloride aqueous solution was added as a polymerization initiator, and polymerization was carried out at 45°C for 10 hours with stirring, resulting in dispersion in the salt aqueous solution. A finely divided polymer was obtained.

The viscosity of this product was 2060 Cp at 25°C, and the viscosity in a 0.5% polymer solution in IN saline was 3 f) cp.

Example 2 In the separable flask used in Example 1, acrylamide 757, ammonium sulfate 501, ammonium hydrogen phosphate 252, and glycerin 3.8? , and 296.2 f of ion-exchanged water were charged, heated to 40°C, and replaced with nitrogen.

Add 0.751 g of ammonium persulfate aqueous solution to this.
．． Adding 0.75 f of aqueous sodium bisulfite solution and polymerizing for 10 hours at 400C under stirring yields a fine particle polymer dispersed in the salt aqueous solution, and the viscosity of this dispersion is 8400 Cp at 25°C. The viscosity in an IN saline solution containing 0.5% polymer was 70.2 cp.

° When 50 r of ammonium hydrogen phosphate was further added to this dispersion, the viscosity decreased to 350 cp.

Example 3 Acrylamide 43.6? (90 mol%), sodium acrylate 6.4 f (I0 mol%), ammonium sulfate 1
12.5? , 2.5 f of pentaerythritol, and 3351 of ion-exchanged water were charged, heated to 40°C, and replaced with nitrogen.

To this was added 1% ammonium persulfate aqueous solution and 17.1 g of hydrogen sulfite aqueous solution, and polymerization was carried out at 40°C for 10 hours with stirring to obtain a polymer of fine particles dispersed in the salt aqueous solution. It was done.

The viscosity of this product is 1830 Cp at 25°C, and the viscosity of the polymer in a 0.5% IN saline solution is 25.50 Cp.
It was P.

Example 4 Acrylamide 51.5% was added to the separable flask used in Example 1. ! M (90 mol%), 2-acrylamide-2
-Sodium methylpropanesulfonate 23.5'?
(I, 0 mol%), ammonium sulfate 106.3? ,
Sorbitol 3.8? , 7'robilene glycol 3.8
1 and 311.1 f of ion-exchanged water, and heated to 45°C.
The reactor was heated to 100°C and replaced with nitrogen.

To this, 3.82 g of 2,2'-azobis(2-amidinopro-gun) hydrochloride aqueous solution of Part 1 was added, and the mixture was heated at 45°C while stirring.
After polymerization at C for 10 hours, a fine particle polymer dispersed in the salt aqueous solution was obtained.

The viscosity of this product is 910 cp at 25°C, and the viscosity of the polymer in a τN saline solution of 0.5 coefficient is 40.7 C1
:l.

Example 5 57.6 t (90 mol) of acrylamide, 4.2 F (5 mol %) of sodium acrylate, and 2-acrylamide were added to the rubble flask used in Example 1.
2-Mefulguronosulfonic acid) IJ U A 1
3.22 (5 mol%), ammonium sulfate 63.8 F
, sodium chloride 42.5 f, polyethylene glycol #4007.5 f, and ion exchange water 311.2 f
f was charged, heated to 45°C, and replaced with nitrogen.

To this, add 2.3t of 1% ammonium persulfate aqueous solution,
2.32 liters of aqueous sodium hydrogen sulfite solution was added and polymerization was carried out at 45°C for 10 hours with stirring to obtain a fine particle polymer dispersed in the salt aqueous solution.

The viscosity of this product is 1200 CI at 25°C.
The viscosity of the polymer in a 0.5% IN saline solution is 35.
It was 1 cp.

Example 6 Into the separable flask used in Example 1, 52.7 t (90 molti) of acrylamide and 22.7 t (90 molti) of acryloyloxyethyldimethylbenzyl ammonium chloride were added.
39 (I0 mole ratio), 5111 aluminum sulfate, 3411 sodium sulfate, 3.811 glycerin, and 336.29 ion exchange water were heated to 45°C and replaced with nitrogen.

To this, 1.5 f of 1% 2,2'-azobis(2-amidinopro-hydrochloride) aqueous solution was added, and while stirring, 45
Polymerization for 10 hours at °C resulted in a finely divided polymer dispersed in an aqueous salt solution.

The product has a viscosity of 2100 Qp at 25°C and a viscosity of 40.3 in a 0.5% polymer iN saline solution.
It was cp.

Example 7 In the separable flask used in Example 1, 35.3 t (65 mol%) of acrylamide and acryloyl-ol I
F-diethyldimethylbenzylammonium chloride 45.49 (22 molti), acryloyloxyethyltrimethylammonium chloride 19. :1 (I3 mol%), ammonium sulfate 68.8 f, ethylene glycol 2.5 f, f-lyethylene glycol #2002
．． 2702 of ion-exchanged water were charged, heated to 45°C, and replaced with nitrogen.

To this was added 1 qlJ of 2,2'-azobis(2-amidinopropane) hydrochloride aqueous solution, and heated at 450C under stirring.
After polymerization for 10 hours at
The viscosity in an aqueous solution of sodium trisulfate containing 0.5% of the polymer was 50.6 cp.

Add 5 ml of ammonium hydrogen phosphate to this dispersion.
When 6.2 f was added, the viscosity decreased to 390 cp.
It became.

Example 8 Acrylamide 56.6. ? (90 molti), methacryloyloxyethyltrimethylammonium chloride 18
．． 49 (I0 mol%), ammonium sulfate 512, ammonium hydrogen phosphate 34, glycerin 2.32,
Ethylene glycol 1.57 and ion exchange water 336.
29 was charged, heated to 50°C, and purged with nitrogen.

To this, 1.57 g of 1% 2,2'-azobis(2-amidinopropane) hydrochloride aqueous solution was added, and the mixture was heated at 50°C while stirring.
After polymerization for 10 hours, a fine particle polymer dispersed in the salt aqueous solution was obtained.

The viscosity of this product is 3510 CI at 25°C.
The viscosity of 0.5% of the polymer in fN saline solution is 15.1
It was (!1).

It is also possible to use a polyelectrolyte dissolved in the salt aqueous solution together with the polyhydric alcohol. Examples are Examples 9 and 1.
0.

Example 9 In the separable flask used in Example 1, a homopolymer of sodium acrylate (a 0.5% pure aqueous solution with a viscosity of 2
l0CI at 5°C) 3.8 f, ammonium sulfate 507, ammonium hydrogen phosphate 25? , globylene glycol 3.82, and ion exchange water 292.47
was added and dissolved, and acrylamide 757 was charged therein, heated to 45°C, and purged with nitrogen.

Add 2.31% 1% ammonium persulfate aqueous solution to this.
Adding 2.3 ml of 1% aqueous sodium bisulfite solution and polymerizing at 45°C for 10 hours with stirring yields a polymer with fine particles dispersed in the salt aqueous solution, and the viscosity of this dispersion is 2.
7200 Cp at 5 °C and 0.5% of polymer
The viscosity in N-saline solution was 35.3 Cp.

When 50 r of potassium sulfate was further added to this dispersion, the viscosity decreased to 450 cp.

Example 10 A homopolymer of acryloyloxyethyltrimethylammonium chloride (an aqueous solution with a viscosity of 5% pure at 20°C at 25°C
p) 2.3 y, ammonium sulfate 852, glycerin 3.8? , and 333.9 r of ion-exchanged water were added and dissolved, and 34.7 r of acrylamide (75
(mol%), acryloyloxyethyltrimethylbenzylammonium chloride (31.59 mol), acryloyloxyethyltrimethylammonium chloride (8.8 r (7 mol)) were charged, and the mixture was heated to 45°C and replaced with nitrogen.

To this, 2.31 g of 1% 2,2'-azobis(2-amitunozolopane) hydrochloride aqueous solution was added, and the mixture was heated at 45°C while stirring.
After polymerization for 10 hours, a fine particle polymer dispersed in the salt aqueous solution was obtained.

The viscosity of this product is 720 cp at 25°C, and the viscosity in an aqueous solution of 0.5% polymer trivalent sodium sulfate is 6.
It was 5Cp.

Comparative Example Into the separable flask used in Example 1, 112.5 F of ammonium sulfate and 337.59 F of ion-exchanged water were added and dissolved, and acrylamide 501 was charged thereto.
It was heated to 0°C and replaced with nitrogen.

To this, 1% ammonium persulfate aqueous solution and 11.1% sulfur hydrogen sulfite aqueous solution were added, and while stirring,
When polymerized at 40°C, the viscosity increased after 10 minutes and the whole became a lump.

(Effects of the Invention) (I) The properties of the products of the present invention produced in Examples and those produced by ordinary aqueous solution polymerization were compared.

Table 1) Solution viscosity is the viscosity of 0.5 ml of polymer in IN saline solution.

2) The monomer composition of the aqueous solution polymerized product is the same as in Example 1.

In this way, products with similar molecular weights were obtained with lower viscosity and fluidity compared to aqueous solution polymerized products.

Patent applicant Kyoritsu Organic Industrial Research Institute Co., Ltd. Procedural amendment September 1985 // [1

Claims (1)

[Scope of Claims] 1. A method characterized in that a polyhydric alcohol is allowed to coexist in polymerizing the acrylic water-soluble monomer (A) while precipitating the polymer in a salt aqueous solution with stirring. A method for producing a fluid water-soluble polymer dispersion. 2. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the water-soluble monomer (A) is acrylamide. 3. A patent claim in which the water-soluble monomer (A) is an alkali metal salt of (meth)acrylate and (meth)acrylamide, and the alkali metal salt of (meth)acrylate is a mixture of monomers containing 15 mol% or less. A method for producing a water-soluble polymer dispersion according to Scope 1. 4. The water-soluble monomer (A) is an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid and (meth)acrylamide, and the alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid is 15 mol% or less. A method for producing a water-soluble polymer dispersion according to claim 1, which is a mixture of monomers. 5. The water-soluble monomer (A) is one or more cationic monomers represented by the following formula (I) and another monomer copolymerizable with this in a molar ratio of 100: 0-5:9
5. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer dispersion is mixed in the following range. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In the formula, R_1 is H or CH_3; R_2 and R_3 are alkyl groups having 1 to 3 carbon atoms; A is an oxygen atom or NH; B is an alkyl group having 2 to 4 carbon atoms; Alkylene group or hydroxypropylene group; X^- is an anionic ion. 2.) The method for producing a water-soluble polymer dispersion according to claim 1, wherein the acrylamide is a mixture of monomers containing 15 mol% or less of the monomer of formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (II) [In the formula, R_1 is H or CH_3; R_2 and R_3 are alkyl groups with 1 to 3 carbon atoms; R_4 is H or C 1 to 3
an alkyl group or an alkanol group;
The method for producing a water-soluble polymer dispersion according to claim 1, which is one kind or a mixture of two or more kinds selected from the group of sorbitol. 8. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the polyhydric alcohol is polyethylene glycol and/or polypropylene glycol having a molecular weight of 600 or less. 9. The water-soluble polymer dispersion according to claim 1, wherein the salt aqueous solution satisfies the conditions that the water-soluble monomer (A) polymer is not dissolved. manufacturing method.