JPH10131093A - Multilayered coating paper for offset rotary printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject coating paper excellent in blocking resistance, resistance to fouling of a backing roll, surface strength and suitability for printing by including a specific copolymer latex in the first coating layer when forming plural pigment coating layers on a base paper. SOLUTION: The objective coating paper is obtained by forming the first coating layer adjacent to a base paper including a copolymer latex obtained by performing an emulsion polymerization of monomers comprising (A) 20-40wt.% aliphatic conjugated diene-based monomer, (B) 0.5-10wt.% ethylenically unsaturated carboxylic acid monomer, (C) 0.5-5wt.% ethylenically unsaturated carbonamide monomer, (D) 5-25wt.% alkyl ester of an ethylenically unsaturated carboxylic acid and (E) 20-74wt.% other copolymerizable monomers when at least two layers of pigment coating layers are formed per one side of the base paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer coated paper for web offset printing. For more information,
The present invention relates to a multilayer coated paper for offset rotary printing having excellent blocking resistance, backing roll stain resistance and surface strength, and good printability.

[0002]

2. Description of the Related Art In recent years, coated paper has been used for a very large number of printed materials because of its high printing effect.
In the periodicals such as quarterly and monthly papers, the number of cases where coated paper is used for all pages has increased considerably. In particular, most of direct mail and product catalogs in the mail order business use coated paper for all pages.

On the other hand, with the advance of printing technology, the speed of the printing process has been increased, and coated paper of a quality that can withstand the demand has been demanded. In particular, in the field of offset rotary printing, coated paper having excellent surface strength, good blister resistance, and high printing gloss is required at the same time.

[0004] For this reason, many techniques for improving coated paper by multilayer coating including double coating have been introduced. For example, JP-A-63-196793, JP-A-1-17469.
8, JP-A-1-250495, JP-A-2-26989
7, JP-A-3-161596 and the like.

According to these techniques, a copolymer latex having a specific gel content (the ratio of an insoluble portion to an organic solvent) has good blister resistance (a property of suppressing the occurrence of blistering upon drying of ink). Japanese Patent Publication No. Sho 59-3598, which discloses the application of a copolymer latex, or Japanese Patent Publication No. Sho 60-17879, which discloses that a copolymer latex containing a vinyl cyanide monomer gives good print gloss. It is a technology that uses a copolymer latex having a specific composition and a specific gel content for each coating layer to improve blister resistance and print gloss. is there.

[0006] However, there is a problem that the mechanical stability of the coating liquid is reduced by reducing the gel content of the copolymer latex.

Further, by lowering the gel content of the copolymer latex, the tackiness of the copolymer latex is increased, the blocking resistance is poor, and the backing roll stains during the coating process. there were.

[0008] The term "blocking resistance" as used herein refers to a property that coated papers after coating do not stick to each other.

[0009]

Means for Solving the Problems In view of the above-mentioned circumstances, the present inventors have conducted intensive studies to solve the present problems, and as a result, have found that a specific composition, By using a copolymer latex of a specific gel content,
The above problems can be solved, and the present invention has been completed.

That is, the present invention relates to a multi-layer coated paper in which at least two or more pigment coating layers are provided on one side of a coated base paper, wherein the first coating layer adjacent to the coated base paper has the following (A): An object of the present invention is to provide a multi-layer coated paper for rotary offset printing excellent in blocking resistance, backing roll stain resistance, strength, gloss and blister resistance, which comprises a polymer latex. (A) 20 to 40% by weight of an aliphatic conjugated diene monomer 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer 0.5 to 5% by weight of an ethylenically unsaturated carboxylic acid amide monomer Unsaturated carboxylic acid alkyl ester monomer 5
A copolymer latex obtained by emulsion polymerization of a monomer consisting of -25% by weight and 20-74% by weight of another copolymerizable monomer, wherein the gel content of the film is 0-70%.
% By weight.

Furthermore, at least one coating layer other than the first coating layer contains a copolymer latex of the following (B), characterized in that the multilayer coating for offset rotary printing is further excellent in strength and printing gloss. Provide paper. (B) 15 to 40% by weight of an aliphatic conjugated diene monomer 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer 0.5 to 5% by weight of an ethylenically unsaturated carboxylic acid amide monomer Unsaturated carboxylic acid alkyl ester monomer 5
A copolymer latex obtained by emulsion polymerization of a monomer consisting of 20 to 79% by weight of a copolymerizable monomer and 20 to 79% by weight of another copolymerizable monomer, wherein the gel content of the film is 20 to 7%.
0% by weight.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The aliphatic conjugated diene monomer in the present invention includes 1,3-butadiene and 2-methyl-1,3-
Butadiene, 2,3-dimethyl-1,3-butadiene,
Examples thereof include 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, substituted and side chain conjugated hexadienes, and one or more kinds can be used. In particular, 1,3-butadiene is preferred.

Examples of the ethylenically unsaturated carboxylic acid monomer include mono- or di-carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Can be.

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

The 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 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 other copolymerizable monomers include an aromatic vinyl monomer, an unsaturated monomer containing a hydroxyalkyl group, and a vinyl cyanide monomer.

The aromatic vinyl 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 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. Particularly, β-hydroxyethyl acrylate is preferable.

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

The amount of each monomer used in the copolymer latex (A) used in the present invention is 20 to 40% by weight of the aliphatic conjugated diene monomer. 20% by weight
If the amount is less than the above, the surface strength of the coated paper is inferior. If the amount exceeds 40% by weight, the surface strength, printing gloss, blocking resistance and backing roll stain resistance of the coated paper are reduced. Preferably 25 to
35% by weight.

The amount of the ethylenically unsaturated carboxylic acid monomer is 0.1.
5 to 10% by weight. If the amount is less than 0.5% by weight, the polymerization stability of the copolymer latex will decrease. If it exceeds 10% by weight, the viscosity of the latex becomes too high, which is not preferable. Preferably, it is 1 to 5% by weight.

The amount of the ethylenically unsaturated carboxylic acid amide monomer is 0.5 to 5% by weight. If the amount is less than 0.5% by weight, the mechanical stability of the coating solution, the anti-blocking property of the coated paper, and the anti-backing roll stain resistance will decrease. If the amount exceeds 5% by weight, the polymerization stability of the copolymer latex will decrease. . Preferably,
0.5 to 3% by weight.

The amount of the ethylenically unsaturated carboxylic acid alkyl ester monomer is from 5 to 25% by weight. If the amount is less than 5% by weight, the blister resistance decreases, and if it exceeds 25% by weight, the blocking resistance and the backing roll stain resistance of the coated paper decrease.

The other copolymerizable monomers are used in an amount of 20 to 74% by weight so that the total amount of the monomers is 100% by weight.

The gel content of the copolymer latex (A) film used in the present invention is from 0 to 70% by weight. If it exceeds 70% by weight, the blister resistance is reduced.

The gel content in the present invention refers to the ratio of the insoluble portion to the toluene in the copolymer latex film. Specifically, the copolymer latex is dried to obtain a copolymer having a known weight. The latex film is immersed in toluene, filtered, weighed dry weight, and calculated by calculating the ratio of the dry weight of the organic solvent insoluble portion of the copolymer to the dry weight of the copolymer.

The number average particle size of the copolymer latex in the present invention can be determined by a dynamic light scattering method.

The amount of the copolymer latex used in the first coating layer is determined by the total pigment used in the first coating layer.
The amount is preferably from 5 parts by weight to 30 parts by weight with respect to parts by weight, and if it is less than 5 parts by weight, the effect on strength becomes small, and if it exceeds 30 parts by weight, it is not preferable in terms of economy.

In the present invention, it is preferable that at least one coating layer other than the first coating layer contains the following copolymer latex (B) in terms of strength and printing gloss. (B) 15 to 40% by weight of an aliphatic conjugated diene monomer 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer 0.5 to 5% by weight of an ethylenically unsaturated carboxylic acid amide monomer Unsaturated carboxylic acid alkyl ester monomer 5
A copolymer latex obtained by emulsion polymerization of a monomer consisting of 20 to 79% by weight of a copolymerizable monomer and 20 to 79% by weight of another copolymerizable monomer, wherein the gel content of the film is 20 to 7%.
0% by weight.

The amount of each monomer used in the copolymer latex (B) is 15
４０40% by weight. Outside this range, the surface strength and printing gloss of the coated paper are reduced. Preferably it is 20 to 35% by weight.

The amount of the ethylenically unsaturated carboxylic acid monomer is 0.1.
5 to 10% by weight. If the amount is less than 0.5% by weight, the polymerization stability of the copolymer latex will decrease. If it exceeds 10% by weight, the viscosity of the latex becomes too high, which is not preferable. Preferably, it is 1 to 5% by weight.

The amount of the ethylenically unsaturated carboxylic acid amide monomer is 0.5 to 5% by weight. If the amount is less than 0.5% by weight, the mechanical stability of the coating solution, the anti-blocking property of the coated paper, and the anti-backing roll stain resistance will decrease. If the amount exceeds 5% by weight, the polymerization stability of the copolymer latex will decrease. . Preferably,
0.5 to 3% by weight.

The amount of the ethylenically unsaturated carboxylic acid alkyl ester monomer is 5 to 25% by weight. If the amount is less than 5% by weight, the blister resistance decreases, and if it exceeds 25% by weight, the blocking resistance and the backing roll stain resistance of the coated paper decrease.

The other copolymerizable monomers are used in an amount of 20 to 79% by weight so that the total amount of the monomers is 100% by weight.

The gel content of the copolymer latex (B) film is 20 to 70% by weight. If the amount is less than 20% by weight, the surface strength of the coated paper decreases, and if it exceeds 70% by weight, the blister resistance decreases.

The copolymer latex (B) used in the present invention preferably has a number average particle diameter of 60 to 250 nm in view of the surface strength of the coated paper, printing gloss and blister resistance.

The amount of the copolymer latex (B) used in the present invention is 5 parts by weight based on 100 parts by weight of the total pigment used in the pigment composition for coated paper containing the copolymer latex (B). Not less than 30 parts by weight, preferably less than 5 parts by weight, the effect on strength is reduced,
If it exceeds 30 parts by weight, it is not preferable in terms of economy.

In the emulsion polymerization of the copolymer latex used in the present invention, the method of adding the various components used is not particularly limited, and any of a batch addition method, a division addition method, and a continuous addition method is employed. be able to. Further, in the emulsion polymerization of the copolymer latex, conventional chain transfer agents, emulsifiers, polymerization initiators, electrolytes, polymerization accelerators, chelating agents and the like can be used.

The method of emulsion-polymerizing the copolymer latex used in the present invention is not particularly limited, either, a method in which all the monomers are added to the reactor in one step, or a method in which an arbitrary monomer is added in a two-step manner. Either a method of adding the monomer to the reactor in stages or a method of adding an arbitrary monomer to the reactor in multiple stages can be adopted, but it is particularly preferable to carry out emulsion polymerization by the following method.

That is, in the first stage, 3 to 3
Adopting a so-called two-stage addition method in which polymerization is started with 40% by weight, preferably 5 to 18% by weight of a monomer, and the remaining monomer is further added as a second step, it is possible to improve the adhesive strength. It is preferred in that respect.

The chain transfer agent used in the present invention includes:
n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan and other alkyl mercaptans, xanthogen compounds such as dimethyl xanthogen disulfide, diisopropyl xanthogen disulfide, α-methyl Compounds such as styrene dimer and terpinolene; thiuram compounds such as tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide; phenols such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol System compounds, allyl compounds such as allyl alcohol, halogenated hydrocarbons such as dichloromethane, dibromomethane, carbon tetrachloride, and carbon tetrabromide Compounds, alpha-benzyloxy styrene, alpha-benzyloxy acrylonitrile, alpha-benzyloxy ethers such as acrylamide, triphenyl ethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalate, 2
-Ethylhexyl thioglycolate and the like, and one or more kinds can be used.

The gel content of the copolymer latex can be adjusted by the amount of the chain transfer agent used.
It is preferable to use 0.05 to 10 parts by weight based on 100 parts by weight of the total of monomers.

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 esters 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.

The number average particle diameter of the copolymer latex can be adjusted by the amount of the emulsifier used.

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

It is preferable to use a polyphosphate as the electrolyte from the viewpoint of the mechanical stability of the coating solution. Examples of the polyphosphate include sodium, potassium and ammonium salts of pyrophosphoric acid, tripolyphosphoric acid, and metaphosphoric acid, and one or more of these can be used.

In the emulsion polymerization, cyclopentene, cyclohexene, cycloheptene, 4-
In addition to cyclic unsaturated hydrocarbons having one unsaturated bond in the ring such as methylcyclohexene and 1-methylcyclohexene, compounds such as benzene, toluene and cyclohexane may be used.

The amount of such a compound used is 1
It is preferably 0.1 to 30 parts by weight with respect to 00 parts by weight in view of surface strength or polymerization stability of the coated paper.

The amount of water used in the emulsion polymerization is preferably from 90 to 400 parts by weight based on 100 parts by weight of the total monomers in view of polymerization stability.

When the copolymer latex used in the present invention is used as one component of a coating solution, for example, the copolymer, together with a pigment, a water-soluble polymer and various additives, may be dissolved in water in which a dispersant is dissolved. A method in which latex is added and mixed, and used as a homogeneous dispersion can be adopted.

Here, examples of the dispersant include sodium pyrophosphate, sodium polyacrylate, sodium hexametaphosphate and the like.

Examples of the pigment include inorganic pigments such as kaolin clay, talc, barium sulfate, titanium oxide, calcium carbonate, aluminum hydroxide, zinc oxide, and satin white; and organic pigments such as polystyrene latex. Are used alone or as a mixture.

Examples of the water-soluble polymer include modified starches such as starch, oxidized starch and esterified starch, natural binders such as soybean protein and casein, and polyvinyl alcohol, carboxymethylcellulose, polyacrylate, polyacrylamide and the like. Derivatives, maleic acid copolymers, polyvinylpyrrolidone and the like can be mentioned.

Examples of various additives include antifoaming agents (polyglycol, fatty acid ester, phosphate ester,
Silicone oil, etc.), leveling agents (funnel oil, dicyandiamide, urea, etc.), preservatives, waterproofing agents, mold release agents (calcium stearate, paraffin emulsion, etc.), fluorescent dyes, etc., and are added as necessary. .

The multilayer coated paper of the present invention has at least two or more pigment coated layers on one side of the coated base paper. The formation of each coating layer is performed by sequentially applying an aqueous coating liquid on a coating base paper. As the coating method, for example, known coating techniques such as blade coating, gate roll coating, roll coating, air knife coating, and bar coating can be used. You can change each one.

The number of coating layers per side is not particularly limited, but is preferably 3 or less, more preferably 2 if there are complicated processes and economic restrictions.

In the manufacturing process including the coating process and the drying process of the multilayer coated paper of the present invention, the coating solution of the first layer is applied.
After passing through the drying step, a method of applying the second layer coating liquid and forming a further subsequent coating layer in the same manner may be used, or the coating liquid of all layers may be continuously applied. And then a drying step to form a coating layer (wet-on-wet method).

After coating and drying, known surface finishing treatments such as a super calender and a machine calender can be applied.

Examples of the pigment used in the present invention include mineral white pigments such as clay, calcined clay, delami clay, heavy calcium carbonate, precipitated calcium carbonate, titanium dioxide, aluminum hydroxide, talc, and satin white, and plastic pigments. Pigments commonly used in the field of paper coating, such as organic synthetic white pigments such as binder pigments and hollow synthetic pigments, can be used alone or in combination of two or more.

[0061]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples in order to clarify the excellent effects of the present invention. It is not limited by the embodiment. The parts and percentages shown in the examples and comparative examples are based on weight unless otherwise specified.

The methods for testing various physical properties in Examples and Comparative Examples are as follows.

Gel content The copolymer latex was treated with sodium hydroxide to obtain a PH =
Adjust to 8.0. Next, the copolymer latex is applied on a glass plate and dried in a hot air drier at 80 ° C. for 4 hours to produce a latex film having a thickness of about 0.5 mm.
Thereafter, about 1.0 g of the latex film was accurately weighed, placed in 400 cc of toluene, allowed to dissolve for 48 hours, filtered through a 300-mesh wire net, dried, and the toluene-insoluble matter (gel) on the wire net was weighed. Calculate the gel content.

Method for Measuring Particle Size of Copolymer Latex The number average particle size was measured by a dynamic light scattering method. In the measurement, LPA-3000 / 3100 (manufactured by Otsuka Electronics) was used.

Mechanical Stability of Coating Liquid Using a commercially available Malon-type mechanical stability tester, the coating liquid (solid content: 40% by weight, sample: 70 g) was subjected to rotor rotation at 1000 rpm, rotor load of 10 kg, and rotation. Time 10
After mechanical shearing under the conditions of minutes, the generated aggregates were captured by a 200 mesh wire mesh. After drying the captured agglomerates, the ratio of the agglomerates to the original sample solids weight was determined in weight percent. According to the determined values, the mechanical stability of the paper coating composition was evaluated on the following three levels.・ ・ ・: Less than 0.01% by weight. Δ: 0.01% by weight or more and less than 0.10% by weight. ×: 0.10% by weight or more.

Each coated paper sample was simultaneously printed on a dry pick RI printer to cause picking. The degree of picking was determined with the naked eye and relatively evaluated from 5 to 1 point. The higher the score, the better.

Using a wet pick RI printer, dampening water was simultaneously applied to each coated paper sample by a Molton roll, and immediately thereafter, each coated paper sample was simultaneously printed by an ink roll to cause picking. . The degree of picking was determined with the naked eye and relatively evaluated from 5 to 1 point. The higher the score, the better.

Suitability for Blister Resistance A coated paper sample printed on both sides was humidified for about one day and night in an atmosphere of 20 ° C. and a relative humidity of 60%, and was thrown into an oil bath capable of variably controlling the temperature. The temperature was determined. The higher the minimum temperature, the better the blister resistance.

White paper gloss JIS. It was measured according to P-8142. The larger the value, the better the glossiness of the blank paper.

Print Gloss After printing each coated paper sample under the same conditions with an RI printer,
Leave it overnight to determine the glossiness of the printed surface according to JIS. P-8142
It measured according to. The higher the value, the better the print gloss.

Adhesion Each coated paper sample was cut into strips 3 cm wide, and the same sample was
Stack them. This is pressed for 10 minutes with a heating and pressing machine at 80 ° C. and 20 kg / cm 2, and then left at room temperature for 1 hour. The pressed test pieces were peeled off one by one four times, and when peeled off, all easily peeled off were evaluated as ○, when there was hardly peeling off 1-3 times, when all were hardly peeled off or not peeled off, they were evaluated as x did.

Backing roll dirt resistance A double-sided printing coated paper is conditioned (8%), placed on an NBR rubber sheet, and then subjected to a linear pressure of about 20 kg / cm by a metal roll heated from above to about 100 ° C. And crimped. Thereafter, the coated paper was peeled off from the rubber sheet, and the degree of dirt on the NBR rubber sheet was judged with the naked eye. A non-dirty one was evaluated as ○, a slightly dirty one was evaluated as Δ, and a considerably dirty one was evaluated as x.

Preparation of Copolymer Latex In a 100 liter autoclave, 120 parts by weight of water were added.
After charging 0.3 parts of sodium tripolyphosphate, 1.0 part of potassium persulfate and the first-stage monomer mixture and chain transfer agent shown in Tables 1 and 2, polymerization was carried out at 70 ° C. for 1 hour. . Thereafter, the second-stage monomer mixture, chain transfer agent and the like were continuously added over 6 hours. The polymerization was continued until the polymerization conversion reached 97%, and the polymerization was completed. After adjusting the obtained copolymer latex to PH8 using sodium hydroxide,
Unreacted monomers and the like were removed by steam distillation to obtain copolymer latexes A-1 to A-8 and B-1 to B-7. A-
In No. 9, since a large amount of aggregates was generated during the polymerization, the polymerization was stopped halfway, and no copolymer latex was obtained.

The gel content and the number average particle size of the obtained copolymer latex were measured, and the results are shown in Tables 1 and 2.

Preparation of Coating Liquid In accordance with the formulation shown in Table 3, using the copolymer latexes A-1 to A-8 shown in Table 1, the first liquid having a solid concentration of 58% was used.
A coating liquid for a coating layer was prepared. A mechanical stability test was performed on the obtained coating liquid, and the results are shown in Table 1.

Preparation of Coating Liquid According to the formulation shown in Table 4, the copolymer latex B-1 to B-7 shown in Table 2 was used to prepare a second liquid having a solid concentration of 64%.
A coating liquid for a coating layer was prepared. A mechanical stability test was performed on the obtained coating liquid, and the results are shown in Table 2.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

Preparation of Multi-Layered Coated Paper A commercially available coated hot air dryer (MLC manufactured by Osugi Corporation)
Coating base paper (basis weight 64 g / m) using -100S type
The obtained coating liquid was applied to both surfaces of 2) to form respective coating layers, and multilayer coated papers 1 to 15 were prepared. The order of formation and the amount of coating were the same on both sides of the coating base paper.

The coating layers were all formed under the same conditions as described below. Coating conditions: Coating was carried out on the above-mentioned hot-air dryer using a wire bar # 3 to # 6 as appropriate. Coating speed is 46m
/ Min. Set to. Drying condition: 0.5 seconds after coating, in a coating hot air drying device kept at 150 ° C, temperature 190 ° C, wind speed 36m /
sec. For 4 seconds.

After the obtained coated paper was conditioned for 24 hours at a relative humidity of 65% and a temperature of 20 ° C., a linear pressure of 70 Kg /
The sheet was subjected to a super calender treatment under the conditions of cm, a temperature of 60 ° C., a paper passing speed of 7 m / min, and paper passing four times, and subjected to a physical property test of each coated paper. Tables 5 and 6 show the results of paper quality evaluations performed on the multilayer coated papers 1 to 15.

[0084]

[Table 5]

[0085]

[Table 6]

[0086]

As described above, a coating composition having excellent mechanical stability can be obtained by using the copolymer latex of the present invention. Furthermore, the multi-layer coated paper obtained by the present invention has extremely excellent anti-blocking properties, anti-backing roll stain resistance and strength, and has excellent printing suitability. Is provided.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takashi Matsuyama 3-1-198, Kasuganaka, Konohana-ku, Osaka Sumika ABS Latex Co., Ltd. Osaka Research Laboratory

Claims (4)

[Claims] 1. A multilayer coated paper in which at least two or more pigment coating layers are provided on one side of a coated base paper, wherein a first coating layer adjacent to the coated base paper contains a copolymer latex of the following (A). A multilayer coated paper for web offset printing characterized by including: (A) 20 to 40% by weight of an aliphatic conjugated diene monomer 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer 0.5 to 5% by weight of an ethylenically unsaturated carboxylic acid amide monomer Unsaturated carboxylic acid alkyl ester monomer 5
A copolymer latex obtained by emulsion polymerization of a monomer consisting of 〜25% by weight and 20-74% by weight of another copolymerizable monomer, wherein the gel content of the film is from 0 to 70%.
% By weight. 2. The multilayer coated paper for web offset printing according to claim 1, wherein at least one coating layer other than the first coating layer contains the following copolymer latex (B). (B) 15 to 40% by weight of an aliphatic conjugated diene monomer 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid monomer 0.5 to 5% by weight of an ethylenically unsaturated carboxylic acid amide monomer Unsaturated carboxylic acid alkyl ester monomer 5
A copolymer latex obtained by emulsion polymerization of a monomer consisting of 20 to 79% by weight of a copolymerizable monomer and 20 to 79% by weight of another copolymerizable monomer, wherein the gel content of the film is 20 to 7%.
0% by weight. 3. The multilayer coated paper for web offset printing according to claim 1, wherein the number average particle diameter of the copolymer latex (A) is from 60 to 250 nm. 4. The multilayer coated paper for web offset printing according to claim 2, wherein the number average particle diameter of the copolymer latex (B) is from 60 to 250 nm.