JP2001200196A - Latex composition for paper coating use and method for producing the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a latex composition for paper coating use having excellent liquid properties and giving a coated paper having excellent high-speed coatability, print strength, especially water-resistant print strength and ink building property. SOLUTION: The objective latex composition for paper coating use is produced by adding 0.1-5.0 pts.wt. (solid basis) of a non-formaldehyde crosslinked amine compound and 0.1-3.0 pts.wt. of a polymer electrolyte to 100 pts.wt. (solid basis) of a copolymer latex having a weight-average particle diameter of 0.05-0.15 μm and produced by the emulsion polymerization of monomers composed of 20-65 wt.% aliphatic conjugated diene monomer, 0.5-10 wt.% ethylenically unsaturated carboxylic acid monomer and 25-79.5 wt.% other monomer copolymerizable with the above monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latex composition for paper coating and a method for producing the same. More specifically, a latex composition for paper coating that provides a coated paper excellent in liquid properties of a latex composition and excellent in high-speed coating suitability and printing strength, particularly water-resistant printing strength, and ink adhesion during offset printing. The present invention relates to a product and a method for producing the same.

[0002]

2. Description of the Related Art Butadiene-based copolymer latex containing butadiene as a main component is widely used as various kinds of binders in the field of paper coating and the like. Various copolymer latexes have been used. The copolymer latex used as these paper coating binders is usually prepared as a paper coating composition together with pigments such as calcium carbonate, kaolin clay and talc and other additives as necessary. Coated on base paper.

[0003] In recent years, as the production of coated paper has increased,
High-speed coating for the purpose of improving coated paper production is progressing. In addition, a high concentration of a paper coating composition for the purpose of coping with a decrease in drying ability accompanying such high-speed coating and improving production efficiency has been promoted. Therefore, in order to cope with these, the paper coating composition is required to have high performance that can withstand high-speed coating and high-concentration coating. For example, in high-speed coating or high-concentration coating in blade coating, excellent high-speed fluidity and water retention are required. If these are inferior, deposits accumulate on the blade edge of the blade, and bleeding (coating on coated paper) Troubles such as residue adhesion and streaks (striations on the coated paper) occur, which greatly affects the coating workability. On the other hand, printing speed has also been increased, and coated paper used for printing is required to have high performance. That is, coated paper is required to have excellent printing strength and water-proof printing strength that can withstand high-speed printing, and particularly in offset printing, ink adhesion under the influence of dampening water is required.

[0004] In order to impart these various properties at the time of printing, a method has been proposed in which, for example, a polyalkylene polyamine-urea-formaldehyde resin or a polyamide-urea-formaldehyde resin is added to a paper coating composition (Japanese Patent Application Laid-Open No. H11-157572). JP-B-44-116677, JP-A-51-1210
No. 41, JP-A-61-281127, JP-A-6-22
No. 8899). Japanese Patent Publication No. 3-4680 proposes a method for preparing a paper coating composition in which an aqueous solution of a specific thermosetting resin is added to a copolymer latex in advance and then mixed with a pigment.

[0005] However, although some improvement can be expected with these methods, it is the present situation that sufficient improvement requests have not been taken, and in particular, the specific method disclosed in Japanese Patent Publication No. 3-4680. In the method of adding an aqueous solution of the thermosetting resin to the copolymer latex in advance, the mixing stability with the copolymer latex used as the binder is inferior, and therefore, there is a problem that the preparation of the binder is considerably restricted. is there.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have made intensive studies to solve the present problems in view of the above-mentioned circumstances, and as a result, have found that a copolymer latex having a specific composition has two specific compounds. Is added at a specific ratio, excellent in the mixing stability of the copolymer latex and the compound, and high-speed coating suitability and printing strength, particularly water-resistant printing strength,
The present inventors have found that this is a latex composition for paper coating which is useful as a binder for providing a coated paper having excellent ink depositability, and completed the present invention.

[0007]

That is, the present invention relates to an aliphatic conjugated diene monomer of 20 to 65% by weight, an ethylenically unsaturated carboxylic acid monomer of 0.5 to 10% by weight and copolymerizable with these. The weight average particle diameter obtained by emulsion polymerization of a monomer comprising 25 to 79.5% by weight of the other monomer is 0.2.
0.1 to 5.0 parts by weight of a non-formaldehyde-based crosslinked amine compound (solids) and 0.1 to 3.0 parts by weight of a polymer electrolyte with respect to 100 parts by weight of a copolymer latex (solids) of 0.5 to 0.15 μm. A latex composition for paper coating characterized by adding 0 parts by weight, and a method for producing the same.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the aliphatic conjugated diene monomer in the present invention,
1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, substituted and side chain conjugated Hexadienes and the like can be used, and one kind or two or more kinds can be used. Especially 1,
3-Butadiene is preferred.

Examples of the ethylenically unsaturated carboxylic acid monomer include mono- or dicarboxylic acids (anhydrides) such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid. One or more of these can be used.

Other monomers copolymerizable with the aliphatic conjugated diene monomer and the ethylenically unsaturated carboxylic acid monomer include alkenyl aromatic monomers and unsaturated carboxylic acid alkyl ester monomers. And unsaturated monomers containing a hydroxyalkyl group, vinyl cyanide monomers, unsaturated carboxylic acid amide monomers and the like.

The alkenyl aromatic monomers include styrene, α-methylstyrene, methyl α-methylstyrene,
Vinyl toluene and divinyl benzene, and the like,
One or more kinds can be used. Particularly, styrene is preferred.

Examples of unsaturated carboxylic acid alkyl ester monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, glycidyl methacrylate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl dimethyl Examples include itaconate, monomethyl fumarate, monoethyl fumarate, 2-ethylhexyl acrylate, and the like, and one or more kinds can be used. Particularly, methyl methacrylate is preferred.

Examples of unsaturated monomers containing a hydroxyalkyl group include β-hydroxyethyl acrylate and β-hydroxyethyl acrylate.
-Hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,
Hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, di- (ethylene glycol) maleate,
Di- (ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis (2-hydroxyethyl)
Maleate, 2-hydroxyethyl methyl fumarate and the like can be mentioned, and one kind or two or more kinds can be used. In particular, β-hydroxyethyl acrylate and β-
Hydroxyethyl methacrylate is preferred.

Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like.
One or more kinds can be used. Particularly, acrylonitrile and methacrylonitrile are preferred.

The unsaturated carboxylic acid amide monomers include:
Acrylamide, methacrylamide, N, N-dimethylacrylamide and the like can be mentioned, and one or more kinds can be used. Particularly, acrylamide and methacrylamide are preferred.

The above monomer composition comprises 20 to 65% by weight of an aliphatic conjugated diene monomer, 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer and other copolymerizable with these. The monomer content is 25 to 79.5% by weight.

If the amount of the aliphatic conjugated diene monomer is less than 20% by weight, the printing strength tends to be poor.

When the amount of the ethylenically unsaturated carboxylic acid monomer is 0.
If it is less than 5% by weight, mechanical stability is poor, and 10% by weight
If it exceeds 300, the viscosity of the latex tends to increase, which is not preferable.

If the amount of the other copolymerizable monomer is less than 25% by weight, the water-proof printing strength tends to be poor, and if it exceeds 79.5% by weight, the printing strength tends to be poor.

The weight average particle diameter of the copolymer latex in the present invention is required to be 0.05 to 0.15 μm from the viewpoint of high speed coating suitability and water resistant printing strength.

The gel content of the copolymer latex is not particularly limited, but is preferably from 10 to 95% by weight.

In the present invention, a copolymer latex is obtained by emulsion-polymerizing the above-mentioned monomer, and the polymerization method is not particularly limited, and may be a one-stage polymerization, a two-stage polymerization, or a multi-stage polymerization. , Power feed polymerization or the like. The method of adding the various components during the emulsion polymerization is not particularly limited, and any of a batch addition method, a division addition method, and a continuous addition method can be employed. Further, in the emulsion polymerization, commonly used emulsifiers, chain transfer agents, polymerization initiators, hydrocarbon compounds, electrolytes, polymerization accelerators, chelating agents and the like can be used.

Examples of the emulsifier include anionic salts such as sulfates of higher alcohols, alkyl benzene sulfonates, alkyl diphenyl ether sulfonates, aliphatic sulfonates, aliphatic carboxylates, and sulfate salts of nonionic surfactants. A surfactant or a nonionic surfactant such as an alkyl ester type, an alkyl phenyl ether type or an alkyl ether type of polyethylene glycol is used alone or in combination of two or more.

Examples of the chain transfer agent include alkyl mercaptans such as n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and n-stearyl mercaptan; xanthogens such as dimethyl xanthogen disulfide and diisopropyl xanthogen disulfide. Compounds, terpinolene, thiuram-based compounds such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, phenolic compounds such as 2,6-di-t-butyl-4-methylphenol, styrenated phenol, allyl Allyl compounds such as alcohols, halogenated hydrocarbon compounds such as dichloromethane, dibromomethane, carbon tetrabromide, α-benzyloxystyrene, α-benzyloxy Siacrylonitrile, vinyl ethers such as α-benzyloxyacrylamide, α-methylstyrene dimer, triphenylethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexyl thioglycolate, and the like. Can be used alone or in combination of two or more.

As the polymerization initiator, a water-soluble polymerization initiator such as potassium persulfate, sodium persulfate and ammonium persulfate, a redox polymerization initiator, and an oil-soluble polymerization initiator such as benzoyl peroxide can be appropriately used.

The hydrocarbon compounds include pentane, hexane, heptane, octane, cyclohexane,
Saturated hydrocarbons such as cycloheptane, unsaturated hydrocarbons such as pentene, hexene, heptene, cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene and 1-methylcyclohexene; and aromatic hydrocarbons such as benzene, toluene and xylene. . In particular, cyclohexene, which has a moderately low boiling point and which can be used to recover and reuse components remaining as unreacted substances after polymerization by steam distillation or the like, is preferred.

In the present invention, based on 100 parts by weight of the copolymer latex (solid content) obtained by the above method,
Non-formaldehyde crosslinked amine compound (solid content)
By adding 0.1 to 5.0 parts by weight and 0.1 to 3.0 parts by weight, the latex composition for paper coating intended for the present invention can be obtained. If the proportion of the non-formaldehyde-based crosslinked amine compound is less than 0.1 parts by weight, the effect of the present invention is insufficient, and if it exceeds 5.0 parts by weight, the printing strength is remarkably reduced, which is not preferable. Preferably it is 0.3 to 3.0 parts by weight. If the proportion of the polymer electrolyte is less than 0.1 part by weight, the effect of the present invention is insufficient, and if it exceeds 3.0 parts by weight, the mixing stability with the pigment is undesirably reduced. Preferably 0.3 to 2.
0 parts by weight.

As described above, by adding a non-formaldehyde-based crosslinked amine compound and a polymer electrolyte to the copolymer latex of the present invention,
It is excellent in mixing stability, and a latex composition for paper coating useful as a binder expressing excellent coated paper performance is obtained.For example, a copolymer latex and a non-formaldehyde-based crosslinked amine compound in the present invention and In the method of mixing the polymer electrolyte and the pigment simultaneously with the pigment, the effect expected in the present invention cannot be exhibited.

Examples of the non-formaldehyde-based crosslinked amine compound used in the present invention include, for example, a reaction product of a heterocyclic amine and a glycidyl compound (Japanese Unexamined Patent Publication No.
140792), a reaction product of a polyalkylene polyamine and a glycidyl compound (JP-A-11-107195).
), A reaction product of a polyalkylene polyamine, an alicyclic compound and a urea (JP-A-11-36188); a reaction product of a polyalkylene polyamine with an α, β-unsaturated monomer and a urea JP-A-11-124794), JP-A-10-195799 and JP-A-11-2377.
Examples thereof include, but are not limited to, crosslinked amine compounds described in No. 96 and the like.

Examples of the polymer electrolyte used in the present invention include an alkali metal salt or an ammonium salt of a polymer having a water-soluble monomer as a main component. Particularly, potassium salt of a polymer having a number average molecular weight of 1,000 to 20,000, comprising 60 to 100 mol% of an ethylenically unsaturated carboxylic acid monomer and 0 to 40 mol% of another monomer copolymerizable therewith. , Sodium salts or ammonium salts are preferred. As the ethylenically unsaturated carboxylic acid monomer,
Acrylic acid, methacrylic acid, crotonic acid, maleic acid,
Mono- or dicarboxylic acids (anhydrides) such as fumaric acid, itaconic acid and the like can be mentioned, and these can be used alone or in combination of two or more.
More than one species can be used. Further, as other monomers copolymerizable with the ethylenically unsaturated carboxylic acid monomer,
Copolymers such as alkenyl aromatic monomers, unsaturated carboxylic acid alkyl ester monomers, hydroxyalkyl group-containing unsaturated monomers, vinyl cyanide monomers, unsaturated carboxylic acid amide monomers, etc. The monomers exemplified in the section of the latex can be mentioned, and one or more kinds can be used respectively.

The paper coating latex composition obtained by the present invention is usually mixed at a ratio of 3 to 20 parts by weight in terms of solid content with respect to 100 parts by weight of the pigment. It is prepared as a product. As the pigment used here,
Examples thereof include inorganic pigments such as kaolin clay, talc, barium sulfate, titanium oxide, calcium carbonate, aluminum hydroxide, and zinc oxide, and organic pigments such as polystyrene latex, and these may be used alone or in combination.

In preparing the paper coating composition,
Starch, oxidized starch, modified starch such as esterified starch, soy protein, natural binders such as casein, or polyvinyl alcohol, polyvinyl acetate latex, synthetic latex such as acrylic latex, etc. Furthermore, other auxiliaries, such as dispersants (sodium pyrophosphate, sodium polyacrylate, sodium hexametaphosphate, etc.), defoamers (polyglycols, fatty acid esters, phosphate esters, silicone oils, etc.), leveling agents (funnel oil, Dicyandiamide, urea, etc.), preservatives, mold release agents (calcium stearate, paraffin emulsion, etc.), fluorescent dyes, color water retention improvers (carboxymethyl cellulose, sodium alginate, etc.) are added as required.

Further, the method of applying the paper coating composition to the coated paper is performed by a coating machine such as a blade coater, a roll coater, and a bar coater. After the application, the surface is dried and finished with a calender ring or the like.

[Examples] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist thereof. In the examples, parts and% indicating percentages are based on weight unless otherwise specified. The evaluation of various physical properties in the examples was based on the following methods.

[0035]Stability of copolymer latex (composition)  Dilute the copolymer latex (composition) to 45%
A 50 g sample of the latex sample,
Under a condition of 10kg load and 10 minutes with a maron type tester
After testing, filter residue on 200 mesh wire mesh
Shown together.

[0036]Evaluation of flowability of paper coating composition  Double cylindrical Hercules high shear viscometer (Osamu Kumagai
(Manufactured by Kiki Kogyo). Using the inner cylinder bob F
Composition for each paper coating at 4000 rpm to give a cutting speed
The apparent viscosity (cps) of the object was measured. The lower number is
It has low apparent viscosity and good fluidity.

[0037]Evaluation of dry pick strength of coated paper  Picking when simultaneously printing each coated paper sample with an RI printing machine
The degree of aging is judged with the naked eye, and it is grade 5 (best) to grade 1.
(Worst) was relatively evaluated.

[0038]Evaluation of wet pick strength of coated paper  Each coated paper sample by Molton roll using RI printing machine
Fountain solution at the same time
Picking when printing each coated paper sample at the same time
The degree is judged with the naked eye, and the level is 5 (best) to 1 (worst
Relatively).

[0039]Evaluation of ink deposition on coated paper  Print while mixing water with ink using RI printing machine
To determine the ink inking property with the naked eye
) To 1st grade (worst).

[0040]Measurement of gel content of copolymer latex  A latex film is prepared at room temperature. afterwards
About 1 g of a latex film is weighed and 400 cc
In toluene for 48 hours to dissolve. Then
This was filtered through a 300 mesh wire mesh and captured by the wire mesh.
After the toluene-insoluble portion is dried and weighed,
The percentage of the weight of the tex film as the gel content
% By weight.

[Example I]Preparation of copolymer latex  In a pressure-resistant polymerization reactor, 70 parts of polymerization water and
0.7 parts of sodium decylbenzenesulfonate, sodium carbonate
Charge 0.2 parts of thorium and 2 parts of cyclohexene, and add 40 parts.
After sufficiently stirring at 4 ° C., 4 parts of butadiene, 3 parts of styrene,
3 parts of methyl methacrylate, 1 part of itaconic acid and meth
1.5 parts of acrylamide was added, and the temperature was raised to 60 ° C.
Thereafter, 1.2 parts of potassium persulfate was added, and
30 minutes later, butadiene 35 parts, styrene
28.5 parts of lene, 12 parts of methyl methacrylate,
Ronitrile 10 parts, fumaric acid 1 part, methacrylamide
1 part, sodium dodecylbenzenesulfonate 0.3
Parts, 4 parts of cyclohexene and 70 parts of polymerization water
The dispersion was added continuously over 8 hours. One hour later 85
Temperature, and stirred for 2 hours.
Addition of 0.05 parts of diethylhydroquinone completes polymerization
did. The polymerization conversion of the obtained copolymer latex was 98.
%Met. Next, the obtained copolymer latex is caustic.
After adjusting the pH to 8 with aqueous sodium hydroxide solution,
Unconcentrated monomers and other low-boiling compounds
This was removed to obtain a copolymer latex A having a solid content of 50%.
The weight average particle diameter of the obtained copolymer latex is 0.0
9 μm, the gel content was 75% by weight.

[0042]Preparation of copolymer latex composition  100 parts by weight of the above copolymer latex A (solid content)
On the other hand, non-formaldehyde crosslinked amine compounds (SP
I-100: manufactured by Sumitomo Chemical Co., Ltd., SPA-179:
Nippon PMC Co., Ltd.) or formaldehyde
Compounds (SR-636: manufactured by Sumitomo Chemical Co., Ltd.) and
And polymer electrolyte (Aron T-40: manufactured by Toagosei Co., Ltd.
Poise 530: manufactured by Kao Corporation)
And added at the ratio shown in Table 1 to obtain the copolymer latex composition.
Products A-1 to 6 were prepared. In addition, these compounds not added
Latex is prepared from these copolymer latex compositions A-1
In order to distinguish from No. 6, copolymer latex A-0 is used.
Table 1 shows the liquid properties of the obtained copolymer latex composition.
You.

[0043]Preparation of composition for paper coating  According to the formulation shown below, the copolymer latex
Using products A-1 to 6 or copolymer latex A-0
To prepare paper coating compositions I-1 to I-7 shown in Table 2.
Was. In addition, about the composition for paper coating I-7, the following formulation
In addition, non-formaldehyde crosslinked amine compounds (SP
0.4 parts of I-100: manufactured by Sumitomo Chemical Industries, Ltd.
Min). Liquid properties of the obtained paper coating composition
Are shown in Table 2. (Formulation of paper coating composition) Kaolin clay 80 parts Heavy calcium carbonate 20 parts Starch oxide 3 parts Dispersant (sodium polyacrylate) 0.5 part Copolymer latex composition or 10 parts Copolymer latex・ ・ ・ ・ ・ ・ ・ Solid content concentration 65%

[0044]Production of coated paper  Using a commercially available hot air coating dryer MLC-100S,
The obtained paper coating composition was applied to a base paper (basis weight 80 g / m2).
Each of the products I-1 to I-7 was coated to prepare a coated paper.
All coated papers were made under the same conditions as shown below.
Was. Coating conditions: Coating of the above composition with the hot air coating dryer described above.
Use a wire bar so that the work volume is 13 g / m2 on one side
And applied. The coating speed is 50 m / min. Set to
Was. Drying condition: about 0.5 seconds after coating, drying oven at 150 ° C
Within 5 seconds with hot air at a temperature of 210 ° C and a wind speed of 33m / s
While drying. Each coated paper obtained was subjected to a relative humidity of 65% and a temperature of 65%.
After conditioning for 24 hours at a temperature of 20 ° C, the linear pressure was 70 kg /
cm, temperature 50 ° C, paper passing speed 7m / min,
Super calender processing under a total of 4 paper passing conditions, each coating
I got the paper. The coated paper thus obtained was subjected to each test and evaluated.
Table 2 shows the results.

[0045]

[Table 1]

[0046]

[Table 2]

[Example II]Preparation of copolymer latex  In a pressure-resistant polymerization reactor, 60 parts of polymerization water and
Sodium ruquil diphenyl ether sulfonate 0.5
Part, α-methylstyrene dimer 1 part, t-dodecylme
0.3 parts of lucaptan was charged and sufficiently stirred at 40 ° C.
Then, butadiene 5 parts, styrene 2 parts, acrylonitrile
3 parts, β-hydroxyethyl methacrylate 1 part, ita
1.5 parts of conic acid was added, and the temperature was raised to 60 ° C. That
Thereafter, 1.5 parts of potassium persulfate was added and polymerization was carried out at 65 ° C.
30 minutes after starting, 40 parts of butadiene, styrene
34 parts, acrylonitrile 12 parts, acrylic acid 1.5
Part, sodium alkyl diphenyl ether sulfonate
0.3 part, 1 part of α-methylstyrene dimer and polymerization water 7
0 parts were added continuously over 10 hours.
Was. One hour later, the temperature was raised to 80 ° C, and the mixture was stirred for 2.5 hours.
After that, diethylhydroquinone was used as a polymerization terminator in 0.1 ml.
The polymerization was terminated by adding 05 parts. Obtained copolymer latte
The polymerization conversion of the resin was 98%. Then the obtained
The copolymer latex to pH 8 with aqueous sodium hydroxide solution
After adjustment, unreacted monomer is removed by stripping and concentration.
And other low-boiling compounds to remove 50% solids
A combined latex B was obtained. The obtained copolymer latex
Has a weight average particle size of 0.11 μm and a gel content of 65
%.

[0048]Preparation of copolymer latex composition  100 parts by weight of the above copolymer latex B (solid content)
On the other hand, non-formaldehyde crosslinked amine compounds (SP
I-100: manufactured by Sumitomo Chemical Co., Ltd., SPA-179:
Nippon PMC Co., Ltd.) and polymer electrolyte
(Aron T-40: manufactured by Toagosei Co., Ltd.)
The copolymer was added at the ratio shown in Table 3 in terms of
Compositions B-1 to B-5 were prepared. These compounds
Latex without any additives
Copolymer latex B- to distinguish it from products B-1 to B-5
Set to 0. The liquid properties of the obtained copolymer latex composition
It is shown in Table 3.

[0049]Preparation of composition for paper coating  According to the formulation shown below, the copolymer latex
Using products B-1 to 5 or copolymer latex B-0
To prepare paper coating compositions II-1 to II-6 shown in Table 4.
Was. The composition for paper coating II-6 has the following formulation.
In addition, non-formaldehyde crosslinked amine compounds (SP
A-179: manufactured by Nippon PMC Co., Ltd.)
(Solid content). The obtained composition for paper coating
Table 4 shows the liquid properties of the product. (Blending composition of paper coating composition) Kaolin clay 50 parts Heavy calcium carbonate 50 parts Oxidized starch 5 parts Dispersant (sodium polyacrylate) 0.5 part Copolymer latex composition or 10 parts Copolymer latex・ ・ ・ ・ ・ ・ ・ Solid content concentration 65%

[0050]Production of coated paper  Using a commercially available hot air coating dryer MLC-100S,
The obtained paper coating composition was applied to a base paper (basis weight 80 g / m2).
Each of the products II-1 to II-6 was coated to prepare each coated paper.
All coated papers were made under the same conditions as shown below.
Was. Coating conditions: Coating of the above composition with the hot air coating dryer described above.
Use a wire bar so that the work volume is 13 g / m2 on one side
And applied. The coating speed is 50 m / min. Set to
Was. Drying condition: about 0.5 seconds after coating, drying oven at 150 ° C
Within 5 seconds with hot air at a temperature of 210 ° C and a wind speed of 33m / s
While drying. Each coated paper obtained was subjected to a relative humidity of 65% and a temperature of 65%.
After conditioning for 24 hours at a temperature of 20 ° C, the linear pressure was 70 kg /
cm, temperature 50 ° C, paper passing speed 7m / min,
Super calender processing under a total of 4 paper passing conditions, each coating
I got the paper. The coated paper thus obtained was subjected to each test and evaluated.
Table 4 shows the results.

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

According to the present invention, by adding two specific compounds at a specific ratio to the copolymer latex of the specific composition of the present invention, the liquidity (viscosity, viscosity, To provide a latex composition which is excellent as a paper coating binder which is excellent in stability) and which can provide a coated paper excellent in high-speed coating suitability, printing strength, especially water resistant printing strength, and ink inking property. Can be done.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) C09D 135/00 C09D 135/00 201/00 201/00 D21H 19/58 D21H 19/58 F-term (reference) 4J038 CA021 CA041 CA051 CA061 CA071 CC041 CG032 CG062 CG072 CG082 CG141 CG161 CG171 CH121 CR072 DJ012 GA01 GA03 GA06 GA09 GA16 JB25 KA08 LA06 MA09 AL04 NA11 NA12 NA24 NA25 PC10 4J100 AB02R ABQR03 A04 AB03A04 AM02R AM15R AM19R AS01P AS02P AS07P BA03R BB01R CA05 DA36 EA09 FA03 4L055 AG11 AG27 AG48 AG63 AG70 AG71 AG72 AG75 AG76 AG89 AG93 AG94 AG97 AG99 AH02 AH37 AJ04 BE07 EA16 EA32 FA15 GA19

Claims (4)

[Claims] 1. An aliphatic conjugated diene monomer of 20 to 65% by weight, an ethylenically unsaturated carboxylic acid monomer of 0.5 to 10%.
% And other monomers copolymerizable therewith.
100 parts by weight of a copolymer latex (solid content) having a weight-average particle diameter of 0.05 to 0.15 μm obtained by emulsion polymerization of a monomer consisting of 9.5% by weight is added to a non-formaldehyde-based crosslinked amine. Compound (solid content) 0.1-5.
A latex composition for paper coating, comprising 0 parts by weight and 0.1 to 3.0 parts by weight of a polymer electrolyte. 2. A polymer electrolyte comprising 60 to 100 mol% of an ethylenically unsaturated carboxylic acid monomer and 0 to 40 mol% of another monomer copolymerizable therewith, having a number average molecular weight of 1
The latex composition for paper coating according to claim 1, which is a potassium salt, sodium salt or ammonium salt of a polymer having a molecular weight of 000 to 20,000. 3. An aliphatic conjugated diene monomer of 20 to 65% by weight, an ethylenically unsaturated carboxylic acid monomer of 0.5 to 10%.
% And other monomers copolymerizable therewith.
100 parts by weight of a copolymer latex (solid content) having a weight-average particle diameter of 0.05 to 0.15 μm obtained by emulsion polymerization of a monomer consisting of 9.5% by weight is added to a non-formaldehyde-based crosslinked amine. Compound (solid content) 0.1-5.
A method for producing a latex composition for paper coating, characterized by adding 0 parts by weight and 0.1 to 3.0 parts by weight of a polymer electrolyte. 4. A polymer electrolyte comprising 60 to 100 mol% of an ethylenically unsaturated carboxylic acid monomer and 0 to 40 mol% of another monomer copolymerizable therewith with a number average molecular weight of 1
The method for producing a latex composition for paper coating according to claim 1, which is a potassium salt, a sodium salt or an ammonium salt of a polymer of 000 to 20,000.