JPH1036458A - Water-based polymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based polymer composition which is mechanically and chemically stable and also a composition for use in producing a coated paper, especially a lightly coated paper or a surface-coated paper, and excellent in water resistance (sizing), surface strength, internal strength, printability, etc. SOLUTION: A water-based polymer composition (A) obtained by polymerizing 99.9-20 pts.wt. polymerizable monomer mixture (b) consisting of 0-60wt.% aliphatic conjugated diene, 0.5-10wt.% ethylenic acid, and 30-99.5wt.% monomer copolymerizable therewith in the presence of 0.1-80 pts.wt. water-soluble polymer (a) comprising at least 60wt.% acrylamide units to thereby yield fine polymer particles (the total amount of the ingredients (a) and (b) being 100 pts.wt.). A water-based polymer composition (B) obtained by mixing 20-99 pts.wt. composition (A) on a solid basis with 80-1 pt.wt. water-soluble polymer comprising at least 60wt.% acrylamide units (the sum of the two ingredients being 100 pts.wt.). A composition for paper coating contains either of the compositions (A) and (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylamide-based polymer, which is one of typical water-soluble polymers as paper and pulp chemicals such as an internal paper strength enhancer or a surface coating agent, and a paper coating agent. By combining a binder, a plastic pigment, and a copolymer latex (polymer fine particles) used as a pigment binder, an aqueous polymer composition having excellent mechanical and chemical stability is provided, and coated paper, particularly fine When using the water-soluble polymer in the production of coated paper or surface coated paper, surface strength,
Provided is a coated paper composition having excellent internal strength, printability, water resistance (size), and the like.

[0002]

2. Description of the Related Art In recent years, the usage ratio of used paper has been increasing in the papermaking industry for environmental protection. Recovered paper contains fine fibers and therefore has weak bonding between pulp and low paper strength. Therefore, a surface coating agent is used in addition to the internal paper strength agent, and the amount thereof is also increasing. Surface coating agents are used for corrugated cardboard exterior liners and other paperboard, high-quality paper, medium-quality paper, coated base paper, newsprint, etc., and modify surface properties, specifically, surface friction, fluff, lubricity , Moisture absorption, gloss, paper powder, picking during printing, internal paper strength, water resistance (size)
It is used for the purpose of improvement. Conventionally used surface coating agents include acrylamide polymers, starch and modified products thereof, cellulose derivatives such as carboxymethyl cellulose, and water-soluble polymers such as polyvinyl alcohol and derivatives thereof. It is difficult to obtain sufficient surface strength with a coating agent,
No improvement in water resistance (size) can be expected. In order to overcome these problems by increasing the amount of coating, new problems such as a decrease in ink set and occurrence of blocking occur. Further, in recent years, for example, in newsprint applications, the weight of the base paper has been reduced, and the surface strength, internal strength, printability, and water resistance (size) of the paper have been increased by increasing the speed of printing and increasing the ratio of offset rotary printing. Problems such as improvement have become apparent. For example, in the field of information recording paper such as ink jet recording paper, the use of special paper and common paper has been promoted, and a slight amount of coating processing (fine coating) has been performed.
There is an increasing demand for imparting sufficient printability and water resistance (size).

[0003]

SUMMARY OF THE INVENTION Under the above-mentioned background, the present invention provides a mechanically and chemically stable aqueous polymer composition, and provides a coated paper, especially a lightly coated paper or a surface coated paper. It is an object of the present invention to provide a coated paper composition having excellent surface strength, internal strength, printability, water resistance (size) and the like when the aqueous polymer composition is used for producing coated paper. It is.

[0004]

Means for Solving the Problems The present invention has been completed by using an aqueous polymer composition containing a water-soluble polymer containing acrylamide as a main component in a specific ratio in an aqueous dispersion of fine polymer particles. .

[0005] The aqueous polymer composition of the present invention comprises a water-soluble polymer (a) containing acrylamide as a main component and polymer fine particles.
(A) a method for producing polymer fine particles in the presence of (a),
(B) a method of mixing (a) with the aqueous polymer composition prepared in (A), and the present invention further provides the aqueous polymer composition as a composition for coated paper. It is characterized by using an object.

That is, the present invention relates to (1) a water-soluble polymer containing 60% by weight or more of acrylamide (a) 0.1
In the presence of -80 parts by weight, the aliphatic conjugated diene monomer 0
-60% by weight, ethylenically unsaturated acid monomer 0.5-10
99.9-20 parts by weight ((a)) of a polymerizable monomer mixture (b) consisting of 30-99.5% by weight (total of 100% by weight of monomers) and 30-99.5% by weight of other copolymerizable monomers. (B) a total of 100 parts by weight) to produce polymer fine particles, and (2) an aqueous polymer composition.
Solid content 20-99 of the aqueous polymer composition according to (1).
80-1 parts by weight of a water-soluble polymer containing 60% by weight or more of acrylamide is mixed with the parts by weight (total 1 part).
00 parts by weight)
(3) A coated paper composition containing the aqueous polymer composition according to (1) or (2).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The water-soluble polymer (a) containing acrylamide as a main component of the present invention will be described. Examples of monomers that can be used by copolymerizing with the acrylamide monomer include ionic, hydrophilic, and hydrophobic monomers, and among the ionic monomers, as the anionic monomer, (Meth) acrylic acid,
Monocarboxylic acids such as crotonic acid and salts thereof, dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid, half esters and salts thereof, 3-butene-1,2,3-tricarboxylic acid and 4-pentene- 1,2,
Tricarboxylic acids such as 4-tricarboxylic acid and aconitic acid and salts thereof, and unsaturated sulfonic acid group-containing unsaturated monomers such as vinylsulfonic acid, styrenesulfonic acid, 2-sulfoethylacrylate, acrylamidepropanesulfonic acid, and acrylamide-tert-butylsulfonic acid. And its salts and the like. Among the ionic monomers, cationic monomers include N, N-dimethylaminoethyl (meth)
Acrylate, N, N-diethylaminoethyl (meth)
Acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, Tertiary amino group-containing unsaturated monomers such as N-dimethylaminopropyl (meth) acrylate and N, N-diethylaminopropyl (meth) acrylate and quaternizing agents such as methyl chloride, dimethyl sulfate and benzyl chloride And a quaternary amino group-containing unsaturated monomer obtained by the reaction with

The hydrophilic monomers include methacrylamide, N-methylol (meth) acrylamide, acetone acrylamide, N, N-dimethyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-
Diethyl (meth) acrylamide, N-propylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, N-acryloylmorpholine, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, various methoxypolyethylene glycol (meth) acrylates , N-vinyl-2-pyrrolidone and the like.

The hydrophobic monomers include N, N-di-n
-Propyl (meth) acrylamide, Nn-butyl (meth) acrylamide, Nn-hexyl (meth) acrylamide, Nn-octyl (meth) acrylamide, N-tert-octyl (meth) acrylamide,
N-alkyl (meth) acrylamide derivatives such as N-dodecylacrylamide, Nn-dodecylacrylamide, N, N-diglycidyl (meth) acrylamide, N
N- (ω-glycidoxyalkyl) such as-(4-glycidoxybutyl) (meth) acrylamide, N- (5-glycidoxypentyl) acrylamide, N- (6-glycidoxyhexyl) acrylamide Meth) acrylamide derivatives, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
(Meth) acrylate derivatives such as dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and glycidyl (meth) acrylate; olefins such as vinyl acetate, vinyl chloride, vinylidene chloride, ethylene, propylene, and butene; acrylonitrile and methacryloyl Ethylene nitrile compounds such as nitrile, styrene, α-
Methylstyrene, butadiene, isoprene and the like can be mentioned. These monomer components can be used alone or in combination of two or more, but the total amount used is preferably less than 40% by weight of the water-soluble polymer component. In some cases, problems such as polymerization stability and storage stability may occur.

Examples of monomers which can be used by copolymerizing with the acrylamide monomer in addition to the above compounds include crosslinkable vinyl monomers. Specific examples include methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and divinylbenzene. Functional crosslinkable monomer or 1,3,5-triacryloylhexahydro-
Examples include polyfunctional crosslinkable monomers such as S-triazine, triallyl isocyanurate, and pentaerythritol triacrylate. The use amount of these crosslinkable vinyl monomers is 5% by weight or less based on the total amount of all monomers constituting the water-soluble polymer containing acrylamide as a main component.
The content is preferably 2% by weight or less from the viewpoint of the uniformity of the crosslinked structure. In addition, it is possible to use glyoxal monourenes such as monomethylol glyoxal monourene, dimethylol glyoxal monourene, monomethyl glyoxal monourene, dimethyl glyoxal monourene, and monomethylol monomethyl glyoxal monourene for the purpose of improving water resistance. (JP-A-6-341095). These are used in an amount of 0.1 to 10 parts based on 100 parts of the water-soluble polymer containing acrylamide as a main component.

The method for polymerizing the water-soluble polymer containing acrylamide as a main component of the present invention is in accordance with a known method for polymerizing a water-soluble polymer, but radical polymerization is preferred. The production method may be either batch polymerization in which all the monomers are charged into a reaction vessel at a time and polymerization, or semi-batch polymerization in which a part of the monomers are continuously added during the polymerization.

The polymerization initiator used in the present invention is not particularly limited, but is preferably a water-soluble initiator. The monomers may be added all at once to the reaction vessel charged, or may be continuously dropped. Specific examples of the initiator include, for example, persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, and di-tert-butyl peroxide. . These initiators can be used alone or as a redox-based polymerization initiator in combination with a reducing agent. Examples of the reducing agent in this case include sulfites, bisulfites, organic amines such as N, N, N ', N'-tetramethylethylenediamine, and reducing sugars such as aldose and ketose. Azo compounds are also preferred initiators, and 2,2'-azobis-2
-Methylpropionamidine hydrochloride, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-N, N'-dimethyleneisobutylamidine hydrochloride, 2,2'-azobis-2- Methyl-N- (2-hydroxyethyl) -propionamide, 2,2′-azobis-2- (2-imidazolin-2-yl) -propane and salts thereof, 4,4′-azobis-4-cyanovaleric acid And its salts can be used. It is also possible to use two kinds of the above-mentioned polymerization initiators in combination.

The chain transfer agent used in the present invention is not particularly limited, but a water-soluble chain transfer agent is preferable. Specific examples thereof include allylsulfonic acid, methallylsulfonic acid and their sodium or potassium salts. And allyl compounds such as allylamine and allyl alcohol; mercaptans such as mercaptoethanol, mercaptopropionic acid and thioglycolic acid; and cysteamine.

The viscosity of the water-soluble polymer containing acrylamide as a main component of the present invention is 50% in an aqueous solution having a concentration of 20% by weight.
It is 0 poise or less, preferably 100 poise or less. If the viscosity is more than the above range, there is a problem that workability is deteriorated and stability at the time of compounding with polymer fine particles is lowered.

Next, a method for forming a composite of a water-soluble polymer and polymer fine particles will be described in detail. (A) A method for producing polymer fine particles in the presence of a water-soluble polymer containing acrylamide as a main component will be described. As the polymer containing acrylamide as the main component, the water-soluble polymer (a) obtained by the above method is used. The range of use of the acrylamide-based polymer is 0.1 to 80 parts by weight, preferably 0.2 to 40 parts by weight, based on 100 parts by weight of the solid content of the aqueous polymer composition. If this amount is less than the above range, mechanical and
Chemical stability may not be sufficient. On the other hand, if it is larger than the above range, the viscosity tends to increase and the polymerization tends not to be carried out stably. The concentration range of the monomer used for polymerizing the polymer fine particles is 5 to 50% by weight, preferably 10 to 50% by weight.
40% by weight. If the concentration is higher than the above range, the polymerization tends not to be carried out stably.

A method for producing polymer fine particles in the presence of a water-soluble polymer containing acrylamide as a main component may be a conventional emulsion polymerization method, except that polymerization is carried out under the above conditions, and is not particularly limited. . However, the use of an emulsifier is not always necessary.

The polymer fine particles of the present invention comprise 0-60% by weight of an aliphatic conjugated diene monomer, 0.5-10% by weight of an ethylenically unsaturated acid monomer, and 3 other copolymerizable monomers.
It is a copolymer consisting of 0 to 99.5% by weight (total 100% by weight of monomers). Specific examples of the aliphatic conjugated diene-based monomer include, for example, 1,3-butadiene, 2-methyl-
Examples thereof include 1,3-butadiene and 2-chloro-1,3-butadiene. These monomers can be used alone or in combination of two or more kinds, and the used amount is 0 to 60% by weight. If the amount is more than the above range, water resistance, whiteness and opacity tend to decrease when used as a composition for coated paper.

Specific examples of the ethylenically unsaturated acid monomers include, for example, monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, and further, methyl maleate and itaconic acid. Half esters such as methyl acid, sulfonic acids such as styrene sulfonic acid, 2-sulfoethyl acrylate and acrylamidopropane sulfonic acid can be exemplified. Also, anhydrides of dicarboxylic acids can be used. These monomers can be used alone or in combination of two or more. Their usage is 0.5-10
% By weight. If the amount is less than the above range, the adhesive strength and stability tend to decrease when used as a composition for coated paper. On the other hand, if it is more than the above range, the viscosity may increase, and the operability may decrease.

Specific examples of other monomers include, for example, aromatic vinyl compounds such as styrene, vinyltoluene and p-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, Acrylic or methacrylic acid ester compounds such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and glycidyl (meth) acrylate; and ethylenically unsaturated carboxylic acid dialkyls such as diethyl fumarate and dimethyl itaconate Esters, acrylonitrile, methacrylonitrile,
Vinyl cyanide compounds such as α-chloroacrylonitrile, (meth) acrylamide, N, N-dimethyl (meth)
Ethylenically unsaturated carboxylic acid amides such as acrylamide and N-methylol (meth) acrylamide and N-substituted compounds thereof, methylaminoethyl (meth) acrylate,
Dimethylaminoethyl (meth) acrylate, methylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, 2-vinyl Examples include ethylenically unsaturated monomers such as ethylenically unsaturated amine compounds such as pyridine and 4-vinylpyridine. These monomers can be used alone or in combination of two or more. Their usage is 30-99.5% by weight. If the amount is less than the above range, the water resistance, whiteness and opacity tend to decrease when used as a composition for coated paper.

The surfactant (emulsifier) used in the present invention is not particularly limited, and nonionic, anionic, amphoteric and polymerizable surfactants can be used. Specifically, for example, a sulfate salt of a higher alcohol such as sodium dodecyl sulfate, a sulfonate-type anionic interface such as sodium (di) alkyldiphenyl ether (di) sulfonate, sodium dodecylbenzenesulfonate, sodium dioctylsulfosuccinate and the like. Surfactants, nonionic surfactants of the type such as alkyl esters of polyethylene glycol, alkyl phenol ethers, alkyl ethers and the like can be used. Examples of the amphoteric surfactant include those having a carboxylate, a phosphate, or a phosphate as an anion portion and an amine salt or a quaternary ammonium salt as a cation portion. Specifically, betaine type,
Glycine-type amphoteric surfactants and the like can be mentioned. Examples of the polymerizable surfactant include, specifically, propenyl-
Anionic polymerizable surfactant such as 2-ethylhexyl sulfosuccinate sodium salt, (meth) acrylic acid polyoxyethylene sulfate, polyoxyalkylpropenyl ether sulfate ammonium salt, (meth) acrylic acid polyoxyethylene ester phosphate, etc. And nonionic polymerizable surfactants such as polyoxyethylene alkyl benzene ether (meth) acrylate and polyoxyethylene alkyl ether (meth) acrylate. These may be used alone or in combination of two or more.

The polymerization initiator used in the present invention includes potassium persulfate, ammonium persulfate and sodium persulfate.
A water-soluble initiator, such as da, may be used alone or in combination with a reducing agent, such as sodium bisulfite or amines, as a redox polymerization initiator. Further, oil-soluble initiators such as a water-soluble azo initiator, benzoyl peroxide and azobisisobutyronitrile can also be used.

As the molecular weight modifier in the present invention, a known molecular weight modifier used in general emulsion polymerization can be used. Specifically, for example, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, mercaptans such as t-tetradecyl mercaptan, dimethyl xanthogen disulfide, diethyl xanthogen disulfide, Xanthogen disulfides such as diisopropylxanthogen disulfide, thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, terpenoids such as terpinolene, α-methylstyrene dimer, 2-ethylhexyl thioglycolate, 3-phenyl -1-pentene, 1,4-cyclohexadiene, hydroquinone,
t-butylcatechol, 2,6-di-t-butyl-4-
In addition to methylphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-xylenol, allyl compounds such as allylamine and allyl alcohol, mercaptans such as mercaptoethanol, mercaptopropionic acid and thioglycolic acid, and cysteamine. Can be mentioned.

(B) A method of blending a water-soluble polymer containing acrylamide as a main component with the aqueous polymer composition prepared by the method (A) will be described. As the water-soluble polymer containing acrylamide as the main component, the water-soluble polymer (a) containing acrylamide as the main component produced by the method described above is used. Complexation by blending is performed by adding and mixing an aqueous solution of a water-soluble polymer (a) to the aqueous polymer composition prepared by the method (A). The concentration range during mixing is (A)
Each of the aqueous polymer composition and the aqueous solution of the water-soluble polymer (a) prepared by the method of
5% or less is preferable. According to this method, there is a problem of stability that occurs when a water-soluble polymer (a) containing polyacrylamide as a main component and ordinary polymer fine particles obtained by emulsion polymerization in the absence of the water-soluble polymer are mixed. The reduction in mechanical stability, chemical stability and storage stability is greatly improved or substantially eliminated.

The aqueous polymer composition of the present invention can be used as it is as a composition for coated paper, or can be used by further blending a pigment or the like. When a pigment is not used, for example, when used as a surface coating agent, the aqueous polymer composition may be used alone or with various chemicals, for example, a sizing agent such as a rosin-based or synthetic system, a water-proofing agent, and a release agent. , An antifoaming agent, a rust inhibitor and the like.
When using a pigment in the composition for coated paper, as the pigment to be used, clay used for ordinary coated paper, light calcium carbonate, heavy calcium carbonate, titanium oxide, aluminum hydroxide, satin white, barium sulfate, Inorganic pigments such as magnesium oxide, talc, and colloidal silica, and organic pigments such as polystyrene, SBR, and phenolic resin can be used alone or in combination of two or more. In addition, dispersants, water-proofing agents, viscosity modifiers, Antifoaming agent, water retention agent, dye, fluorescent dye, solvent, pH adjuster, surfactant,
Preservatives, other auxiliaries, additives and the like can be used as needed.

The composition for coated paper thus obtained is applied by a coating apparatus such as a blade coater, bar coater, gate roll coater, size press, calender, spray or the like.

The coating base paper of the present invention has a basis weight of 40-3.
Use newspaper base paper, medium quality paper, high quality paper and paperboard of 00 g / m 2. The coating amount of the composition for coated paper on these base papers is 0.1-25 g / m 2 on one side in a dry state. The coated paper is finished by various methods such as a calender.

[0027]

The present invention will now be described more specifically with reference to examples. In the examples, “%” and “parts” are based on weight.

Production of water-soluble polymer (a) containing acrylamide as a main component 80.71 parts of deionized water was placed in a five-necked flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen gas inlet pipe, and a dropping port.
90 parts of a 50% aqueous acrylamide solution and 6.25 parts of an 80% aqueous acrylic acid solution were charged, and the temperature of the aqueous solution was adjusted to 30 ° C. while blowing nitrogen gas. To this aqueous solution, 0.28 parts of ammonium persulfate was added as an initiator in deionized water 3
To 6.52 parts, 0.13 part of sodium bisulfite as a reducing agent of a redox initiator was dissolved in 35.52 parts of deionized water, respectively, and then added to start the reaction. 60
Polymerization for minutes, without controlling the temperature of the aqueous solution during that time,
Spontaneous fever was caused. The reaction was terminated by cooling, and Brookfield B type viscosity at 25 ° C. was 20% of 30 cps.
A water-soluble polymer (1) was obtained. In the same manner, after adjusting the temperature of the aqueous solution of the monomer mixture to 30 ° C., 2.68 parts of sodium methallylsulfonate is added, and 1.05 part of ammonium persulfate is added as an initiator to 36.52 parts of deionized water. After dissolving 2.32 parts of sodium bisulfite as a reducing agent of a redox initiator in 35.52 parts of deionized water, the mixture was added to start a reaction. Polymerization was carried out for 60 minutes, during which temperature control of the aqueous solution was not performed, and spontaneous heat generation was performed. The reaction was terminated by cooling, and a 20% water-soluble polymer (2) having a Brookfield type B viscosity of 12 cps at 25 ° C. was obtained.

Production Comparative Example 1 Into an autoclave equipped with a stirrer, 100 parts of deionized water was charged and adjusted to 65 ° C. while purging with nitrogen, and then 0.5 part of sodium dodecylbenzenesulfonate and 1.8 parts of potassium persulfate were added. Added. To this aqueous solution, 34 parts of butadiene emulsified using a homogenizer and styrene 60 were added.
Parts, a total of 100 parts by weight of a monomer mixture of 1 part by weight of acrylic acid, 2 parts of itaconic acid, and 3 parts of methacrylamide.
0.6 parts of dodecyl mercaptan, 2,4-dimethyl-6
-T-butylphenol (trade name: Anti-Oxid
ant No. 30 / E. I. DU PONT NEM
OURS & Co. (Inc., INC) 1.2 parts, an emulsion consisting of 0.3 parts of sodium dodecylbenzenesulfonate and 50 parts of deionized water was added continuously for 6 hours, and then the polymerization was continued for another 8 hours to complete the polymerization. The polymerization was completed at a polymerization conversion of 98%. Then, the obtained polymer fine particle dispersion is p-pulped using sodium hydroxide.
After adjusting to H6, steam was blown in to remove unreacted monomers.
Polymer fine particles (1) were obtained.

Production Example 1-2 (Production of aqueous polymer composition obtained by polymerizing polymer fine particles in the presence of water-soluble polymer (a) containing acrylamide as a main component) In an autoclave equipped with a stirrer, 350 deionized water was added. After adjusting the temperature to 65 ° C. while purging with nitrogen, 100 parts of a 20% aqueous solution of a water-soluble polymer (1) containing acrylamide as a main component, 0.5 part of sodium dodecylbenzenesulfonate, 1.8 parts of potassium persulfate Is added. This aqueous solution was emulsified using a homogenizer, and a monomer mixture of butadiene (34 parts), styrene (60 parts), acrylic acid (1 part), itaconic acid (2 parts), and methacrylamide (3 parts) in total was 10 parts.
0 parts by weight and 0.6 parts of tert-dodecyl mercaptan,
2,4-dimethyl-6-t-butylphenol 1.2
, An emulsion consisting of 0.3 parts of sodium dodecylbenzenesulfonate and 50 parts of deionized water was added continuously for 6 hours, and then the polymerization was continued for another 8 hours to complete the polymerization. Finished. Next, the obtained aqueous polymer composition is adjusted to pH 6 using sodium hydroxide, and then unreacted monomers are removed by blowing steam, and the aqueous polymer composition having a solids concentration of 35% is further distilled by heating under reduced pressure. (1) was obtained. In the same manner, an aqueous polymer composition (2) was obtained using the water-soluble polymer (2) as the water-soluble polymer containing acrylamide as a main component.

Production Example 3-5 In the same manner as in Production Example 1, the amounts of the deionized water initially charged in the autoclave and the aqueous solution of the water-soluble polymer (1) containing acrylamide as the main component (1) were each 390 parts by weight. Except for changing to 50 parts by weight, 270 parts by weight and 200 parts by weight or 180 parts by weight and 10 parts by weight, according to the method of Production Example 1, aqueous polymer compositions (3), (4) and (3) having a solid content of 35% (5) was obtained.

Production Example 6-8 (Production of Aqueous Polymer Composition by Blend of Fine Polymer Particles Containing Water-Soluble Polymer Containing Acrylamide as Main Component and Water-Soluble Polymer Containing Acrylamide as Main Component) 13450 g of a 20% aqueous solution of the water-soluble polymer (1) containing acrylamide as a main component was added to 450 g of the aqueous polymer composition (2) having a solid content of 35% by stirring with a stirrer. % Of an aqueous polymer composition (6) was obtained. In a similar manner, 71.6 g of a 20% aqueous solution of a water-soluble polymer (1) containing acrylamide as a main component was added to 450 g of the aqueous polymer composition (3) having a solid content of 35% obtained in Production Example 3.
Addition and 139 g of a 20% aqueous solution of a water-soluble polymer (1) containing acrylamide as a main component were added to 450 g of the aqueous polymer composition (5) having a solid content of 35% obtained in Addition and Production Example 5 to give a solid content of 35%. Thus, aqueous polymer compositions (7) and (8) were obtained.

Production Example 9 An aqueous polymer composition (9) was obtained in the same manner as in Production Example 1, except that tert-dodecylmercaptan was not used.

Production Example 10 An aqueous polymer composition (10) was obtained in the same manner as in Production Example 1, except that the amounts of styrene and butadiene were changed to 84 parts and 10 parts, respectively.

Comparative Production Example 2 Polymer fine particles (2) were obtained in the same manner as in Production Comparative Example 1, except that tert-dodecyl mercaptan was not used.

Comparative Production Example 3 Polymer fine particles (3) were obtained in the same manner as in Production Comparative Example 1, except that the amounts of styrene and butadiene were changed to 84 parts and 10 parts, respectively.

Production Comparative Example 4-6 (Water-soluble polymer containing acrylamide as a main component (a) and fine polymer particles (b)
Production of Aqueous Polymer Composition by Blend) Acrylamide adjusted to a solid concentration of 10% was added to 250 g of each of the aqueous polymer particle dispersions (1) to (3) adjusted to a solid concentration of 40% with stirring. 200 g of an aqueous solution of a water-soluble polymer (1) as a main component was added, and the obtained aqueous polymer composition was adjusted to pH 6 using sodium hydroxide, and then heated under reduced pressure to obtain an aqueous polymer having a solid content of 35%. Compositions (11)-(13)
I got

The physical properties (a)-(e) of the aqueous polymer compositions (1)-(13) and polymer fine particles (1)-(3) obtained in Production Example 1-10 and Production Comparative Example 1-6 were measured. The measurement or evaluation was performed according to the following methods, and the results are shown in Table 1.

(A) Gel content The polymer fine particles and the aqueous polymer composition were uniformly cast on a polypropylene plate, dried at room temperature for 1 week, and dried in a hot air circulating drier at 80 ° C. for 1 hour to form a film. Is formed. After accurately weighing about 1 g with an analytical balance and immersing it in 100 ml of toluene for 2 days, 10 ml of a toluene solution is collected, and the solid content after drying is weighed, and the gel content is calculated by the following method.

(Equation 1) (B) Viscosity The viscosity was adjusted to 25% by adjusting the solid content of the polymer fine particles and the aqueous polymer composition to 35% and using a BE type viscometer.
At 60 ° C. and 60 ° C., the guidelines were read after 60 seconds.

(C) Chemical Stability An aqueous calcium chloride solution having a solid content of 5% was added to polymer fine particles having a solid content of 35% and 30 g of the aqueous polymer composition. Stability was evaluated on the following four scales. ◎: 50 ml or more ：: 25 ml or more and less than 50 ml △: 10 ml or more and less than 25 ml ×: less than 10 ml (d) Mechanical stability 150 g of polymer fine particles having a solid concentration of 20% or an aqueous polymer composition (pH 6) was measured using a Marlon tester. After applying mechanical shearing with a load of 15 kg for 20 minutes, this was filtered through a 300-mesh wire gauze, the amount of solidified material remaining on the mesh was measured (in terms of solid content), and the ratio to the sample was determined. It was evaluated on a scale. ：: less than 100 ppm △: 100 ppm or more-less than 1000 ppm ×: 1000 ppm or more (e) Storage stability Take an aqueous polymer composition having a solid content of 20% in a graduated cylinder, leave at room temperature for 30 days, and observe the phase separation state. did. ○: No phase separation ×: With phase separation

Coating Example 1 The aqueous polymer composition (1) obtained in Production Example 1
%, 5%, and 10%, respectively, by diluting with deionized water. Next, using a blade coater, length 28 cm, width 1
By adjusting the solid content of the aqueous polymer composition and the blade pressure of a blade coater on a base paper having a basis weight of 44 g / m 2 adjusted to 8 cm, a dry coating amount (hereinafter simply referred to as a coating amount) of 0.2 g / m2, 0.5 g / m2, 1.5 g / m2
Was applied on one side. After coating, the coated paper was dried in a drum dryer at 70 ° C. for 50 seconds to obtain a coated paper. The coated paper was subjected to seasoning at a constant temperature and humidity (temperature of 20 ° C., humidity of 65%) for 24 hours, and the following physical properties were evaluated. The results are shown in Table 2.

(1) Blank glossiness Using a gloss meter GM-3D manufactured by Murakami Color Co., Ltd., an angle of 75 was used.
The specular gloss of ゜ was measured. (2) Printing gloss Using an RI printing suitability tester (manufactured by Mei Seisakusho), printing with ink (Toyo Ink Mark Five New Indigo)
After seasoning at constant temperature and humidity (temperature 20 ° C, humidity 65%) for a period of time, use a gloss meter GM-3D manufactured by Murakami Color Co., Ltd.
The specular gloss at an angle of 60 ° was measured. (3) Dry pick strength Using an RI printing suitability tester (manufactured by Mei Seisakusho), printing with ink (Toyo Ink SMX Tack 25) was used to visually determine the peeling state, and the 5-point method (5 points was excellent, One point was evaluated as poor). (4) Wet pick strength Using a RI printing suitability tester (manufactured by Akira Seisakusho), wet the paper surface with a Molton roll, immediately print with ink (Toyo Ink SMX Tack 25), and visually check the peeling state. The evaluation was made according to a 5-point method (5 points excellent, 1 point poor). (5) Ink acceptability test Using a RI printing suitability tester (manufactured by Meiji Seisakusho), wet the paper surface with a Molton roll, immediately print with ink (Toyo Ink SMX Tack 25), and use the ink accepting density 5
Evaluation was made by the point method (5 points excellent, 1 point poor). (6) Ink setting test Using an RI printing suitability tester (manufactured by Mei Seisakusho), printing was performed every 10 seconds with ink (Toyo Ink Mark Five New Indigo), and ink density was transferred by pressing art paper on the printing surface. For 24 hours at a constant temperature and humidity (temperature of 20 ° C., humidity of 65%), and then measured with a Macbeth ink densitometer (Sakata Inx Co., Ltd.). (7) Stiffness test A coated paper sample was adjusted to 5 cm in length and 2.5 cm in width, and a Gurley stiffness tester (Kumaya Riki Kogyo Co., Ltd.)
Was used for the measurement. (8) Break length measurement test Adjust the coated paper sample to 15 cm long and 1.5 cm wide,
The measurement was carried out using a digital tensile tester (manufactured by Sagawa Seisakusho). (9) Size test A test was conducted by a water drop method. After 1 μl of deionized water was dropped on the coated paper, the time until the water droplet on the surface of the coated paper disappeared was measured and expressed in seconds.

Coating Example 2-10 The aqueous polymer composition (2)-(1) obtained in Production Example 2-10
0) was diluted to a solid content of 5% to obtain a coated paper having a coating amount of 0.5 g / m 2 in the same manner as in Coating Example 1. The physical properties were evaluated in the same manner as in Coating Example 1. The results are shown in Table 2.

Coating Comparative Example 1 The above physical properties were evaluated using base paper having a basis weight of 44 g / m 2, and the results are shown in Table 2.

Coating Comparative Example 2 The water-soluble polymer (1) containing acrylamide as a main component was adjusted to a solid content of 2%, 5% and 10% by diluting with deionized water, respectively. m2, 0.5g / m2,
A coated paper of 1.5 g / m 2 was obtained in the same manner as in Coating Example 1.
These samples were also evaluated for physical properties as described above, and the results are shown in Table 2.

Coating Comparative Examples 3-5 and 6-8 The aqueous polymer composition (11)-(1) obtained in Production Comparative Example 1
3) and polymer fine particles (1)-(3) at a solid content of 5%
To obtain a coated paper having a coating amount of 0.5 g / m 2 in the same manner as in Coating Example 1. These samples were also evaluated for physical properties as described above, and the results are shown in Table 2.

Comparative Comparative Example 9 A 1-liter four-neck separable flask equipped with a stirrer, a reflux condenser and a thermometer and a heating device (water bath) were prepared, and 889 g of deionized water was charged into the separable flask. Then, 111 g of commercially available oxidized starch (Ace A: manufactured by Oji Cornstarch Co., Ltd.) was added thereto. After stirring at 90 ° C. for 30 minutes, the mixture was cooled to room temperature with ice water. The obtained 10% aqueous starch solution was diluted to 5%, and a coated paper having a coating amount of 0.5 g / m 2 was obtained in the same manner as in Coating Example 1. This sample was also evaluated for physical properties as described above, and the results are shown in Table 2.

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[Table 1]

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[Table 2]

[0050]

[Table 3]

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[Table 4]

[0052]

According to the present invention, there is provided an acrylamide polymer which is one of typical water-soluble polymers as paper and pulp chemicals such as an internal paper strength enhancer or a surface coating agent, and a binder for paper coating. By combining copolymer latex (polymer fine particles) used as a plastic pigment and a pigment binder, it provides an aqueous polymer composition with excellent mechanical and chemical stability, as well as coated paper, especially fine coated When the water-soluble polymer is used for the production of paper or surface-coated paper, water resistance (size),
Provided is a coated paper composition having excellent surface strength, internal strength, printability and the like.

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location D21H 1/34 E (72) Inventor Goro Kuwamura 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Saburo Hayano 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemicals Co., Ltd. (72) Inventor Kenichi Nakane 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Mitsui Toatsu Chemicals Co., Ltd.

Claims (3)

[Claims] 1. An aliphatic conjugated diene-based monomer in the presence of 0.1 to 80 parts by weight of a water-soluble polymer (a) containing 60% by weight or more of acrylamide. 0.5-10% by weight of the monomer 30-99.5% by weight of the other copolymerizable monomer (100% by weight of the total monomer) 99.9-20% by weight of the polymerizable monomer mixture (b) Aqueous polymer composition characterized in that polymer parts are produced by polymerizing parts (total 100 parts by weight of (a) and (b)). 2. An aqueous polymer composition according to claim 1, wherein acrylamide is added in an amount of 6 to 99 parts by weight on a solid basis.
An aqueous polymer composition characterized by mixing 80-1 parts by weight of a water-soluble polymer containing 0% by weight or more (100 parts by weight in total). 3. A composition for coated paper, comprising the aqueous polymer composition according to claim 1.