JPH10212320A - Production of anionic water-soluble polymer dispersion, anionic water-soluble polymer dispersion, and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer dispersion having a low viscosity, a good workability, and an excellent storage stability by polymerizing a monomer component contg. (meth)acrylic acid in an aq. salt soln. in the presence of a cationic water-soluble polymer. SOLUTION: The monomer component contg. (meth)acrylic acid comprises 15-100mol% acrylic acid and 0-85mol% acrylamide. The cationic water-soluble polymer is, e.g. a dimethyldiallylammonium chloride (co)polymer. The wt. ratio of the monomer component to the cationic water-soluble polymer is (100:1)-(10:1). A chloride, sulfate, or nitrate of an alkali metal (e.g. Na or K) or ammonium is used as the salt for forming the aq. salt soln. The concn. of the salt is from 5wt.% to the saturation concn. In a papermaking process, the aq. soln. is mixed into a paper material and then a water-diluted polymer dispersion is added to the material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anionic water-soluble polymer dispersion having good storage stability and good workability, which is effective for a papermaking method for improving the yield and / or drainage in the papermaking process. .

[0002]

2. Description of the Related Art In the papermaking process, a papermaking method is known in which a cationic or amphoteric water-soluble polymer is added to and mixed with paper stock, and then bentonite is added and mixed to improve the yield and / or drainage. . However, bentonite is a powder and has a disadvantage that workability is remarkably poor.
Further, a method is known in which acrylic acid / acrylamide is polymerized in a salt aqueous solution in which a monomer is dissolved and a formed polymer is not dissolved to obtain a dispersion of polymer fine particles (Japanese Patent Application Laid-Open No. 60-185900). . However, the fine particles in the acrylic acid / acrylamide (co) polymer dispersion obtained by the method have the property of coalescing upon standing and solidify in a tofu state, which is not practical. For this reason, of course, the dispersion has not been commercialized. JP-A-62-20511 discloses a method for obtaining a water-soluble polymer dispersion by polymerizing a monomer in a salt aqueous solution in which a monomer is dissolved and a formed polymer is not dissolved in the presence of a polymer electrolyte. Although disclosed, it is specified that the ionicity of the polymer electrolyte and the monomer are the same.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the technique described in JP-A-60-185900 to obtain an anionic water-soluble polymer dispersion having good storage stability and good workability. It is intended to be used in a papermaking method or the like for improving the yield and / or drainage in the papermaking process of papermaking. One of the objects of the present invention is to produce a high-quality paper by averaging the composition distribution in the thickness direction of the paper layer by using a method for improving the yield of fillers, etc. The advantage of reducing paper stock density and controlling the variation of paper making it easier to mass-produce paper of a certain quality or extending the life of plastic wire An inexpensive papermaking method is provided. Another purpose of the present invention is to improve drainage. The purpose of drainage improvement is generally to increase papermaking speed, but it is often used for the purpose of enhancing paper strength. That is, if the degree of beating of the pulp is improved, it is possible to increase the paper strength, but there is a disadvantage that the paper making speed is reduced. By using the method for improving drainage, it is possible to maintain the filtration speed and the drying speed of a wet paper web at the same level as pulp having a high degree of beating even for pulp having a high degree of beating. It is regarded as important as a papermaking method that enables the production of high-performance paper by making a stock using pulp with a high degree of beating without lowering the production speed.
It is an object of the present invention to provide an anionic water-soluble polymer dispersion having excellent workability and storage stability that is effective for achieving the above object.

[0004]

Means for Solving the Problems The present inventors dissolve a monomer containing (meth) acrylic acid in the presence of a cationic water-soluble polymer and dissolve the monomer and dissolve the resulting polymer in an aqueous salt solution. By conducting polymerization in water, an anionic water-soluble polymer dispersion having low viscosity, good workability and excellent storage stability can be produced. Was found to improve the yield and / or drainage by adding and mixing an aqueous diluent of the anionic water-soluble polymer dispersion of the present invention after adding and mixing, and reached the present invention.

The invention of claim 1 of the present invention is characterized in that, in the polymerization of a monomer containing (meth) acrylic acid in an aqueous salt solution, the polymerization is carried out in the presence of a cationic water-soluble polymer. To produce an anionic water-soluble polymer dispersion.

The invention of claim 2 of the present invention is characterized in that a monomer containing (meth) acrylic acid is dissolved, and the polymerization is carried out with stirring in an aqueous salt solution which does not dissolve the produced polymer. Item 10. A method for producing an anionic water-soluble polymer dispersion according to item 1.

According to a third aspect of the present invention, the anionic aqueous solution according to any one of claims 1 to 2, wherein the polymerization is carried out under stirring in a salt aqueous solution in which the cationic water-soluble polymer is dissolved. This is a method for producing a conductive polymer dispersion.

The invention of claim 4 of the present invention is characterized in that the composition of the monomer containing (meth) acrylic acid contains 15 to 1 acrylic acid.
The method for producing an anionic water-soluble polymer dispersion according to any one of claims 1 to 3, wherein the monomer composition contains 0 to 85 mol% of 00 mol% acrylamide.

The invention according to claim 5 of the present invention is characterized in that the cationic water-soluble polymer is a dimethyldiallylammonium chloride (co) polymer, and the anionic water-soluble polymer according to claims 1 to 4 is characterized in that: This is a method for producing a polymer dispersion.

The invention according to claim 6 of the present invention is characterized in that the weight ratio of the monomer containing (meth) acrylic acid to the cationic water-soluble polymer is 100: 1 to 10: 1. A method for producing an anionic water-soluble polymer dispersion according to any one of Items 1 to 5.

According to a seventh aspect of the present invention, a water-soluble polymer particle comprising a polymer of a monomer containing (meth) acrylic acid having a particle size of 100 μm or less is dispersed in an aqueous salt solution, and An anionic water-soluble polymer dispersion, characterized in that a cationic water-soluble polymer is contained in the liquid in a ratio of 100: 1 to 10: 1 based on the weight of the water-soluble polymer particles.

The invention according to claim 8 of the present invention is characterized in that the composition of the monomer containing (meth) acrylic acid contains 15 to 1 acrylic acid.
The anionic water-soluble polymer dispersion according to claim 7, which has a monomer composition containing 0 to 85 mol% of 00 mol% acrylamide.

According to a ninth aspect of the present invention, a cationic polymer is added to and mixed with a stock in the papermaking process of neutral papermaking, and then the production is performed by the production method according to any one of the first to sixth aspects. A papermaking method comprising adding a water dilution of the anionic water-soluble polymer dispersion according to claim 7 or 8.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first limitation of the present invention is to carry out polymerization of a monomer containing (meth) acrylic acid in an aqueous salt solution in the presence of a cationic water-soluble polymer. This is a method for producing a characteristic anionic water-soluble polymer dispersion. A second limitation of the present invention is that in the method for producing an anionic water-soluble polymer dispersion according to claim 1, a salt aqueous solution in which a monomer containing (meth) acrylic acid is dissolved and a produced polymer is not dissolved. It is characterized in that the polymerization is carried out under stirring in the inside. A third limitation of the present invention is that in the method for producing an anionic water-soluble polymer dispersion according to claim 1 or 2, the polymerization is carried out under stirring in a salt aqueous solution in which the cationic water-soluble polymer is dissolved. It is characterized by the following. A fourth limitation of the present invention is that, in the method for producing an anionic water-soluble polymer dispersion according to any one of claims 1 to 3, the composition of the monomer containing (meth) acrylic acid is 15 to It is characterized by a monomer composition containing 0 to 85 mol% of 100 mol% acrylamide. A fifth limitation of the present invention is that, in the method for producing an anionic water-soluble polymer dispersion according to any one of claims 1 to 4, the cationic water-soluble polymer is a dimethyldiallylammonium chloride (co) polymer. It is characterized by. According to a sixth limitation of the present invention, in the method for producing an anionic water-soluble polymer dispersion according to any one of claims 1 to 5, the method includes the step of preparing a monomer containing (meth) acrylic acid and a cationic water-soluble polymer. The weight ratio is 100: 1 to 10: 1. A seventh limitation of the present invention is that a water-soluble polymer particle composed of a polymer of a monomer containing (meth) acrylic acid having a particle size of 100 μm or less is dispersed in an aqueous salt solution, and the cationic liquid is dispersed in the dispersion. The water-soluble polymer is 10% based on the weight of the water-soluble polymer particles.
An anionic water-soluble polymer dispersion liquid characterized by being contained at a ratio of 0: 1 to 10: 1. An eighth limitation of the present invention is that in the anionic water-soluble polymer dispersion according to claim 7, the composition of the monomer containing (meth) acrylic acid is 15 to 100% by mole of acrylic acid and 0 to 100% by mole of acrylamide. It is characterized by a monomer composition containing 85 mol%. A ninth limitation of the present invention is that the cationic polymer is added to and mixed with the stock in the papermaking process of neutral papermaking, and then manufactured by the manufacturing method according to any one of claims 1 to 6. Item 10. A papermaking method comprising adding a water dilution of the anionic water-soluble polymer dispersion according to item 8.

Examples of the cationic water-soluble polymer used in the present invention include dialkylaminoalkyl (meth) acrylate salts or quaternary compounds or dialkylaminoalkyl (meth) acrylamide salts or quaternary compounds. It can be selected from coalesced and dialkyldiallylammonium salt (co) polymers. Examples of the salt or quaternary compound of dialkylaminoalkyl (meth) acrylate include dimethylaminoethyl methacrylate hydrochloride, acryloyloxyethyltrimethylammonium chloride, and the like. Examples of the salt or quaternary compound of dialkylaminoalkyl (meth) acrylamide include dimethylaminopropylacrylamide hydrochloride and methylated product. As the dialkyldiallylammonium salt, dimethyldiallylammonium chloride can be mentioned. Not only one kind of cationic monomer but also a mixture of two or more kinds can be used. The cationic monomer may be a homopolymer or a copolymer with a nonionic monomer such as acrylamide. A particularly preferred cationic water-soluble polymer is dimethyldiallylammonium chloride (co) polymer.

As the monomer containing (meth) acrylic acid used in the present invention, acrylic acid alone, methacrylic acid alone, itaconic acid alone, these acids, acrylamide, acrylonitrile, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl acrylate A mixture with one kind of nonionic monomer selected from ethyl methacrylate, vinyl methyl ether, vinyl acetate and a mixture thereof is used. Among these (meta)
A monomer having an acrylic acid-containing monomer composition having a molar ratio of acrylic acid: acrylamide of 100: 0 to 15:85 is most awarded, and furthermore, a ternary copolymer containing acrylonitrile. Coalescing is also preferably used.

The salt forming the aqueous salt solution used in the present invention includes chlorides, sulfates, nitrates and the like of alkali metal salts such as sodium and potassium or ammonium salts. As the salt concentration in these salt aqueous solutions, a salt concentration of 5% by weight or more to a saturated concentration is appropriately used.
As a characteristic property of the salt aqueous solution, it is an essential condition that the monomer containing (meth) acrylic acid is dissolved and the resulting polymer is not dissolved. On the other hand, the coexisting cationic water-soluble polymer needs to be soluble in the salt aqueous solution. (Meta)
The ratio of the monomer containing acrylic acid to the cationic water-soluble polymer is 100: 1 to 10: 1, and if the amount of the cationic water-soluble polymer is too small, the dispersion is curd into a tofu form,
Being too large is economically meaningless.

The papermaking method of the present invention comprises a cationic polymer,
For example, an aqueous solution such as cationic starch or cationic polyacrylamide is added to and mixed with the stock, and then a water diluent of a (meth) acrylic acid-containing monomer polymer produced by the production method of the present invention is added. It is characterized by the following. The feature of the present invention resides in that a polymer of a monomer containing (meth) acrylate is not used. For example, a (meth) acrylic acid (co) polymer is hardly soluble, has a low viscosity even in the case of a high molecular weight substance, and does not require strong stirring to disperse and mix it in paper stock. A dispersion of polymer fine particles obtained by carrying out polymerization in an aqueous salt solution that dissolves the monomer and does not dissolve the formed polymer of the present invention as the (meth) acrylic acid (co) polymer most suitable for this purpose. It is simple and desirable to add a water diluent to the stock.

The pH of the stock used in the present invention is 6.5 to 6.5.
9.0 neutral papermaking. At this pH, the (meth) acrylic acid (co) polymer dissociates from the (meth) acrylate (co) polymer, thickens, and aggregates due to a synergistic effect with the cationic or amphoteric polymer added in the previous stage. It exerts its power and improves the yield and drainage. The amount of the (meth) acrylic acid (co) polymer that is effective for improving the yield and drainage is 50 to 500 ppm per stock SS. If the amount is too small, there is no effect of improving the yield and drainage. If the amount is too large, floc formation occurs and the quality of the formed paper is deteriorated.

[0020]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

[Synthesis example of (meth) acrylic acid (co) polymer] A monomer having the composition shown in Table 1 and polydimethyldiallylammonium chloride (CPS) were placed in a reactor equipped with a stirrer, a nitrogen aeration tube and a temperature controller. Agefloc-WT40HV (trade name, manufactured by the company) in saline (NaCl) such that the monomer concentration per product is 20% by weight.
(18% by weight aqueous solution), 2,2′-azobis (2-amidinopropane) hydrochloride was added as a polymerization initiator, and the resulting mixture was polymerized at 50 ° C. for 10 hours with stirring, and dispersed in an aqueous salt solution. A polymer of fine particles having a diameter of 10 to 20 μm was obtained. The viscosity of the polymer dispersion was 500 mPa · s or less, and the molecular weight was determined from the intrinsic viscosity based on an aqueous solution dissolved in water to which sodium carbonate was added. Monomer composition of each sample,
Table 1 shows the amount of polydimethyldiallylammonium chloride added, the molecular weight, and the presence or absence of curd.

[0022]

[Table 1]

(Effect test 1) The results of measuring the filler yield and the total yield with a brit type dynamic jar tester are shown in Table-2. The stock used in the test was 900 ppm charcoal, 300 ppm kaolin, and 4000 pulp.
ppm, PH 8.1, CSF 300 ml medium quality paper. The procedure is as follows. 500 ml of the stock is charged into a britt type dynamic jar tester, stirring is started at 1500 rpm, and a 0.1% by weight aqueous solution of polymer of Himoloc NR12ML (acrylamide / acryloyloxyethyltrimethylammonium chloride copolymer) is added.
0 seconds later, a 0.1% by weight water dilution of the polymer described in Table 1 is added. After another 30 seconds, the cock for collecting white water is opened, and the white water that has passed through the 150 mesh wire is allowed to flow out. The white water for the first 10 seconds was discarded, and then the white water for 30 seconds was collected and used for measurement, and the total yield and the incineration at 600 ° C. were determined for the filler yield. The chemical addition amount is an addition amount per solid content with respect to the paper amount, and is a Hymoloc NR12ML.
Is referred to as a first-stage polymer, and the polymers described in Table 1 are referred to as a second-stage polymer.

[0024]

[Table 2]

(Effect test 2) Ash content in paper was set to 20 using a fourdrinier on-top type paper machine under the conditions of stock pH 8.1 to 8.3.
%, High-quality paper having a basis weight of 84.0 g / m ² was made. The filler composition is 80% light calcium carbonate and 20% talc. To the seed box, 5000 ppm of cation starch (cationization rate of corn starch raw material) to pulp was added, and the prepolymer was added as a 0.15% by weight aqueous solution immediately before the inlet of the fan pump. Papermaking was performed by adding a water concentration of 0.03% by weight of a polymer diluent, and the total yield and filler yield were determined from the SS and ash content of the flow box and the white water pit. The results are shown in Table-3. The chemical addition amount is an addition amount per solid content with respect to the paper amount, and the name of the polymer is the same as in the effect test 1. In all of the formulations of the present invention, a 10% or more improvement in papermaking speed when only the first-stage polymer was added was observed.

[0026]

[Table 3]

[0027]

According to the papermaking method of the present invention, the yield of cellulose fiber and filler can be improved in the papermaking process, and the effect of increasing the papermaking speed is also recognized. The fact that a high (meth) acrylic acid (co) polymer effective for coagulation can be used in a low-viscosity dispersion state with good long-term storage stability without being carded has great economic value.

[Table 2]

[Table 2]

[Procedure amendment]

[Submission date] October 16, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

As the monomer containing (meth) acrylic acid used in the present invention, acrylic acid alone, methacrylic acid alone, itaconic acid alone, these acids, acrylamide, acrylonitrile, methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl acrylate A mixture with one kind of nonionic monomer selected from ethyl methacrylate, vinyl methyl ether, vinyl acetate and a mixture thereof is used. Among these (meta)
A monomer having an acrylic acid-containing monomer composition having a molar ratio of acrylic acid: acrylamide of 100: 0 to 15:85 is most awarded, and furthermore, a ternary copolymer containing acrylonitrile. Coalescing is also preferably used.
The (meth) acrylic acid (co) polymer dispersion in the present invention is prepared by dissolving the above monomer in an aqueous salt solution, maintaining the system in a deoxygenated state under a nitrogen atmosphere, and adding 2,2′-azobis (2-
Obtaining a desired polymer by performing radical polymerization by adding a water-soluble azo polymerization initiator such as amidinopropane) hydrochloride or a water-soluble redox polymerization initiator used in combination with ammonium persulfate and sodium hydrogen sulfite Can be. A known arbitrary supply method such as a method in which the entire amount of the monomer is previously charged into the reaction apparatus, a method in which a part is previously charged in the reaction apparatus and the remaining amount is continuously added, and a method in which the entire amount is continuously added can be adopted. The temperature of the polymerization system can be arbitrarily selected in the range of 0 to 100 ° C. depending on the properties of the polymerization initiator. Addition of a chain transfer agent such as isopropyl alcohol or mercaptan for controlling the molecular weight can be arbitrarily selected as in the case of ordinary radical polymerization. In the production of the (meth) acrylic acid (co) polymer dispersion, it is necessary to perform stirring at a peripheral speed of 1 m / min or more in order to smoothly precipitate the fine polymer particles. As long as the contents do not overflow from the apparatus, there is no upper limit on the stirring speed, and any stirring conditions can be selected.

Claims (9)

[Claims] 1. An anionic water-soluble polymer dispersion characterized in that, in the polymerization of a monomer containing (meth) acrylic acid in an aqueous salt solution, the polymerization is carried out in the presence of a cationic water-soluble polymer. Liquid production method. 2. The anionic aqueous solution according to claim 1, wherein the monomer containing (meth) acrylic acid is dissolved, and the polymerization is carried out with stirring in a salt aqueous solution in which the produced polymer is not dissolved. Method for producing conductive polymer dispersion. 3. The polymerization is carried out under stirring in an aqueous salt solution in which the cationic water-soluble polymer is dissolved.
A method for producing the anionic water-soluble polymer dispersion according to claim 2. 4. The composition of a monomer containing (meth) acrylic acid is a monomer composition containing 15 to 100 mol% of acrylic acid and 0 to 85 mol% of acrylamide. A method for producing the anionic water-soluble polymer dispersion according to claim 3. 5. The method for producing an anionic water-soluble polymer dispersion according to claim 1, wherein the cationic water-soluble polymer is a dimethyldiallylammonium chloride (co) polymer. 6. The weight ratio of the monomer containing (meth) acrylic acid to the cationic water-soluble polymer is 100: 1 to 10:
The method for producing an anionic water-soluble polymer dispersion according to any one of claims 1 to 5, wherein 7. A water-soluble polymer particle comprising a polymer of a (meth) acrylic acid-containing monomer having a particle size of 100 μm or less is dispersed in an aqueous salt solution, and a cationic water-soluble polymer is dispersed in the dispersion. Molecule is 100:
An anionic water-soluble polymer dispersion, which is contained in a ratio of 1 to 10: 1. 8. The monomer composition containing (meth) acrylic acid is a monomer composition containing 15 to 100 mol% of acrylic acid and 0 to 85 mol% of acrylamide. 3. The anionic water-soluble polymer dispersion according to item 1. 9. The method according to claim 7, wherein the cationic polymer is added to and mixed with the stock in the papermaking process of neutral papermaking, and then the paper is manufactured by the manufacturing method according to claim 1. A paper-making method, comprising adding a water diluent of the anionic water-soluble polymer dispersion of (1).