JPH0931894A - Matte coated paper for web offset printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet of coated paper for the web offset printing improved in good balance among various characteristics such as surface strength, water and blister resistances and inking properties. SOLUTION: This sheet of coated paper for the web offset printing is prepared by coating the top surface of a sheet of base paper with a coating composition consisting essentially of a pigment and an adhesive and drying the coated composition. The adhesive is especially a copolymer latex, prepared by charging a monomer mixture containing the total amount of (2) an ethylenically unsaturated dicarboxylic acid and methacrylic acid in ethylenically unsaturated carboxylic acids in an amount of <=40wt.% based on the total amount of a monomer mixture containing (1) a conjugated diene-based monomer, (2) the ethylenically unsaturated carboxylic acids and (3) an ethylenically unsaturated carboxylic acid other than the monomer (2) into a polymerization reactor by collective adding and carrying out the emulsion copolymerization is blended in an amount of 1-30 pts.wt. based on 100 pts.wt. pigment in the first charging stage in carrying out the emulsion copolymerization of the monomer mixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to coated paper for off-wheel printing, particularly for off-wheel printing in which various characteristics such as surface strength, water resistance, ink receptivity, and blister resistance are improved in a well-balanced manner. It relates to coated paper.

[0002]

2. Description of the Related Art In recent years, coupled with the rapid increase in demand for coated paper,
The printing speed has become higher and higher due to the higher paper coating speed and the increased production of printed matter. This tendency is particularly strong in offset printing. As described above, the following paper qualities are demanded for printing paper with the improvement in productivity and the increase in printing speed.

First, the coated paper is required to have excellent surface strength. That is, generally, the coating composition constituting the coating layer contains a pigment as a main component, and when the adhesive strength is low, the coating force is applied to the coated paper surface coated with such a composition by a mechanical force during printing. The pigment may fall off from the layer, or the coated layer may peel off from the base paper. The destruction of the coating layer becomes more serious as the printing speed increases and the number of times of overprinting increases. Therefore, the coated paper is required to have higher surface strength.

Secondly, it is necessary that the surface of the coated paper has excellent water resistance. Especially in offset printing,
During the printing process, fountain solution is used to moisten the printing plate. Therefore, the coated layer is required to have a mechanical resistance against printing in a wet state, that is, excellent water resistance.

Thirdly, with the increase in printing speed,
In offset rotary printing (off rotary printing), the conditions for drying and heating are becoming more severe, and the coating layer is required to have much better ink receptivity and blister resistance than in the past.

As described above, in the case of offset printing paper, especially coated paper for offset printing, various characteristics such as surface strength, water resistance, ink receptivity, and blister resistance are required. However, the conventional methods have not provided coated papers having all of these characteristics at a high level and in good balance. The reason is that these properties largely depend on the physical properties (gel content, particle size, glass transition point, etc.) of the adhesive in the coating composition, especially the copolymer latex, and the surface strength depends on these physical properties. , Water resistance, ink receptivity and blister resistance are greatly influenced. That is,
Among the physical properties of the copolymer latex, if they are limited to a certain specific physical property and, for example, a countermeasure for improving the surface strength is exhibited, the blister resistance is deteriorated and the respective properties show contradictory properties.

As a specific example, conventionally, as a method for improving the surface strength of coated paper for printing, a method for increasing the gel content of the copolymer latex has been known. However, if the gel content is increased, the water resistance and the blister resistance of the resulting coated paper for printing are deteriorated. On the other hand, as a method for improving the ink receptivity, a method is known in which the particle size of the copolymer latex is increased or the glass transition point is increased. On the other hand, if this measure is taken, there are problems such as deterioration of the surface strength and water resistance of the coated paper.

As a method for solving such a problem, for example, JP-A-61-63794 and JP-A-63-1.
1308, JP-A-1-192896, and the like propose to devise a method of adding a polymerization chain transfer agent or a polymerization initiator at the time of producing a copolymer latex. However, when the copolymer latex thus obtained is used as an adhesive in a coating composition to finish coated paper for off-ring printing, surface strength, water resistance, ink receptivity, or blister resistance is obtained. In reality, it is not sufficient from the viewpoint of finishing a coated paper for printing which has various characteristics such as a good balance.

[0009]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in order to solve the problems in the conventional coated paper for off-wheel printing as described above. As a result, the present invention uses a specific copolymer latex as an adhesive in a coating composition to provide a coating for off-ring printing such as surface strength, water resistance, ink receptivity, and blister resistance. It is intended to provide a coated paper in which the paper quality characteristics required for the paper are improved in an extremely well-balanced manner.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a coated paper for off-ring printing, which comprises coating a base paper with a coating composition containing a pigment and an adhesive as main components and drying the coated paper. When emulsion-polymerizing a monomer mixture containing (1) a conjugated diene monomer, (2) an ethylenically unsaturated carboxylic acid, and (3) an ethylenically unsaturated monomer other than (2), In the charging stage of (2), the total amount of ethylenically unsaturated dicarboxylic acid and methacrylic acid in the ethylenically unsaturated carboxylic acid is included, and 40% by weight of the total amount of the monomer mixture is used.
Charge the following by adding them all at once in the polymerization reactor,
A copolymer latex obtained by performing emulsion polymerization,
And the copolymer latex is 1 per 100 parts by weight of the pigment.
The coated paper for offset printing is characterized in that the content is ˜30 parts by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have used a specific copolymer latex as an adhesive component in a coating composition for coated paper for off-wheel printing to obtain surface strength, water resistance, The inventors have found that a coated paper for off-wheel printing, which has an excellent balance of ink receptivity and blister resistance, can be obtained, and completed the present invention.

That is, in the present invention, as an adhesive to be added to the coating composition, (1) a conjugated diene monomer, (2) an ethylenically unsaturated carboxylic acid and (3) an ethylenic unsaturated monomer other than (2) In emulsion polymerization of a monomer mixture containing a saturated monomer, in the first charging step, (2) the monomer containing all of the ethylenically unsaturated dicarboxylic acid and methacrylic acid among the ethylenically unsaturated carboxylic acids A coated paper for off-wheel printing, characterized in that 40% by weight or less of the total amount of the mixture is charged into a polymerization reactor by batch addition, and a copolymer latex obtained by emulsion polymerization is used. is there.

The method for producing the specific copolymer latex used in the coated paper for offset printing of the present invention will be described in detail below. First, as the (1) conjugated diene-based monomer, for example, 1,3-butadiene, isoprene, 2
-Chloro-1,3-butadiene, 2-methyl-1,3-
Examples thereof include butadiene and the like which have been generally used in the conventional production of copolymer latex. Then, one kind of these conjugated diene-based monomers or two or more kinds thereof are appropriately combined and used. Particularly, 1,3-butadiene is preferably used.

The conjugated diene-based monomer is used to impart appropriate elasticity and film hardness to the copolymer latex obtained, and the mixing ratio thereof is 20 to 20 with respect to the total monomer mixture. It is in the range of 50% by weight. By the way, when it is less than 20% by weight, sufficient surface strength may not be obtained, while when it exceeds 50% by weight, water resistance and surface strength of the obtained coated paper may decrease.

Next, (2) ethylenically unsaturated carboxylic acids (monomers) include, for example, monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, and dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid. And their anhydrides,
Examples thereof include monoesters of dicarboxylic acids such as methyl maleate and methyl itaconic acid, that is, half-esters. Among these ethylenically unsaturated carboxylic acid monomers, especially in the present invention, ethylenically unsaturated dicarboxylic acid and methacrylic acid are used as essential components. Of course, ethylenically unsaturated carboxylic acid monomers other than ethylenically unsaturated dicarboxylic acid and methacrylic acid can also be used in an appropriate combination.

The amount of these ethylenically unsaturated carboxylic acid monomers used is 0.2 to 12 with respect to the total monomer mixture.
It is adjusted in the range of 0.5% by weight, preferably 0.5 to 8% by weight. Incidentally, when it is less than 0.2% by weight, the mechanical stability of the obtained copolymer latex becomes unstable, and the surface strength of the coated paper obtained by using such a copolymer latex decreases. I'm worried. On the other hand, if it exceeds 12% by weight, the viscosity of the copolymer latex obtained becomes too high, and it may not be suitable for practical use. The amount of the ethylenically unsaturated dicarboxylic acid and methacrylic acid used is
0.1 to 10% by weight based on the solid content of the total monomer mixture,
It is preferably about 0.5 to 5% by weight. The ratio of ethylenically unsaturated dicarboxylic acid and methacrylic acid is, for example, ethylenically unsaturated dicarboxylic acid / methacrylic acid =
10/90 to 90/10 (% by weight), preferably 25 /
It is about 75 to 75/25 (% by weight).

Further, (3) the ethylenically unsaturated monomer other than the ethylenically unsaturated carboxylic acid monomer, for example, styrene, α-methylstyrene, vinyltoluene, p
-Aromatic vinyl compounds such as methylstyrene, and unsaturated compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate Ethylenically unsaturated carboxylic acid amide compounds such as carboxylic acid alkyl ester compounds, acrylamide, methacrylamide, N, N-dimethylacrylamide and N-methylolacrylamide, carboxylic acid vinyl esters such as vinyl acetate, acrylonitrile, methacrylonitrile, α -Vinyl cyanide compounds such as chloracrylonitrile, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth)
Acrylate, dimethylaminopropyl (meth) acrylate, dibutylaminoethyl (meth) acrylate,
Examples thereof include ethylenically unsaturated amine compounds such as dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, 2-vinylpyridine and 4-vinylpyridine.

These may be used alone or in appropriate combination of two or more. Among them, styrene is preferably used as the aromatic vinyl compound, methyl methacrylate is preferably used as the unsaturated carboxylic acid alkyl ester compound, and acrylonitrile is particularly preferably used as the vinyl cyanide compound.

The amount of the ethylenically unsaturated monomer other than the ethylenically unsaturated carboxylic acid used is 20 to 79.8% by weight, preferably 50 to 7% by weight based on the total monomer mixture.
It is in the range of 9.8% by weight. By the way, when it is less than 20% by weight, the water resistance of the coated paper using the obtained copolymer latex tends to be lowered, while when it exceeds 79.8% by weight, the rigidity of the obtained copolymer latex is low. There is a concern that the surface strength of the coated paper obtained may be lowered due to too high a value.

The polymerization chain transfer agent used in the emulsion polymerization for preparing the copolymer latex according to the present invention is
It is not particularly limited, and a general chain transfer agent generally used in emulsion polymerization can be used. Specific examples include 2-mercaptopropionic acid and 3-
Mercaptocarboxylic acids such as mercaptopropionic acid and mercaptoacetic acid, or salts thereof (for example, ammonium mercaptoacetate), mercaptandicarboxylic acids such as mercaptosuccinic acid or salts thereof (such as mercaptandicarboxylic acid salt), 2-mercaptoethanol, 3
-Mercaptans having a hydroxyl group in the molecule such as mercapto-1,2-propanediol, mercaptans having an amino group in the molecule such as 2-mercaptoethylamine, thioglycolic acid, and 3,3'-thiodipropionic acid Having a carboxyl group in the molecule thereof or a salt thereof, a monosulfide having a hydroxyl group in the molecule such as β-thiodiglycol, a monosulfide having an amino group in the molecule such as thiodiethylamine, and dithiodiglycol Acids, 2,2'-dithiodipropionic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid and other disulfides having a carboxyl group in the molecule or salts thereof, thiodiglycolic anhydride Anhydrides of monosulfides and disulfides, such as D-, L- or D -Disulfides having a carboxyl group and an amino group in the molecule such as cystine, chloromethanol, 2-chloroethanol, 1-chloro-2-propanol, 2 or 3-chloro-n-propanol, 2-, 3- Or halogenated hydrocarbons having a hydroxyl group in the molecule such as 4-chloro-n-butanol, chloropentanol, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, chlorodifluoroacetic acid, 2-chloropropyroic acid, 3-chloropropion Acid, 2-bromopropionic acid, 3-bromopropionic acid, 2-bromopentanoic acid, chlorosuccinic acid, chlorofumaric acid, chloromaleic acid, chloromalonic acid, and the like, halogenated hydrocarbons having a carboxyl group in the molecule or salts thereof. Halogenated carbon, such as chloromaleic anhydride Acid anhydrides of the hydrogen acids, hexyl mercaptan,

Monothiols such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, 1,10-decanedithiol, 1,14
-Tetradecanedithiol, dithiol such as triglycol dimercaptan, trithiol such as 1,5,10-decanetrithiol, trimethylolpropane tristhioglycolate, tetraerythrone such as pentaerythritol tetrakisthioglycolate and pentaerythritol tetrakisthiopropionate Polythiols having at least two mercapto groups in the molecule such as thiols, xanthogen disulfides such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthigen disulfide, and thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetrabutylthiuram disulfide. , Halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, ethylene bromide, Mercaptocarboxylic acid alkyl esters such as captoacetic acid-2-ethylhexyl ester, mercaptopropionic acid-2-ethylhexyl ester and mercaptopropionic acid tridecyl ester, mercaptoacetic acid methoxybutyl ester, mercaptopropionic acid methoxybutyl ester and other mercaptocarboxylic acid alkoxyalkyl Esters, carboxylic acid mercaptoalkyl esters such as octanoic acid-2-mercaptoethyl ester and α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene,
Examples include anisole and allyl alcohol.

These chain transfer agents may be used alone or in appropriate combination of two or more kinds. In the copolymer latex used in the present invention, especially monothiol, polythiol, xanthogen disulfide, thiuram disulfide, carbon tetrachloride, mercaptoacetic acid-2-ethylhexyl ester, octanoic acid-2-mercaptoethyl ester, mercaptoacetic acid methoxybutyl ester. , Mercaptopropionic acid methoxybutyl ester, α-methylstyrene dimer, terpinolene and the like are preferably used. These chain transfer agents are usually used in an amount of 0.05 to 20 parts by weight, preferably 0.1% to 100 parts by weight of the total monomer mixture.
It is adjusted in the range of 1 to 15 parts by weight, more preferably 0.2 to 10 parts by weight.

As the emulsion polymerization method, a conventionally known emulsion polymerization method is appropriately adopted. For example, emulsion polymerization is carried out by adding a monomer mixture, a polymerization initiator, an emulsifier, a polymerization chain transfer agent and the like to an aqueous medium such as water.

The polymerization initiator is not particularly limited, and examples thereof include inorganic persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, cumene hydroperoxide, benzoyl peroxide, isopropylbenzene peroxide and the like. An organic peroxide, an azo-based initiator such as azoisobutyronitrile, or the like can be used. These may be used alone or in combination of two or more. Among these polymerization initiators, persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate are preferably used from the viewpoint of polymerization stability. Further, in the emulsion polymerization of the copolymer latex used in the present invention, the above-mentioned polymerization initiator is
It is also possible to use it as a so-called redox type polymerization initiator which is combined with a reducing agent such as sodium bisulfite and ferrous sulfate. The amount of the polymerization initiator used is usually adjusted in the range of 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the total monomer mixture.

Further, the emulsifier used in the emulsion polymerization of the copolymer latex is not particularly limited, and examples thereof include sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium dodecyl diphenyl ether disulfonate, and dialkyl ester succinate. Anionic surfactants such as sodium acid, nonionic surfactants such as polyoxyethylene alkyl esters and polyoxyethylene alkylaryl ethers, alkyl betaine type salts such as salts of lauryl betaine and stearyl betaine, and lauryl-β-alanine , Amphoteric surfactants such as amino acid type such as lauryldi (aminoethyl) glycine and octyldi (aminoethyl) glycine salts. These may be used alone or in appropriate combination of two or more. Among these emulsifiers, sodium dodecylbenzene sulfonate or sodium dodecyl diphenyl ether disulfonate is particularly preferably used.

The amount of such an emulsifier used is usually from 0.05 to 2. per 100 parts by weight of the total monomer mixture used.
The amount is 5 parts by weight, preferably 0.1 to 1.5 parts by weight. Incidentally, when the amount exceeds 2.5 parts by weight, the water resistance of the coated paper obtained tends to be poor, and further, when the coating composition is applied to the base paper, the foaming of the coating composition becomes violent, resulting in coating. It is not preferable because it reduces the operability.

The copolymer latex may be polymerized in the presence of a chelating agent such as sodium ethylenediaminetetraacetate, a dispersant such as sodium formaldehyde sulfoxylate, an inorganic salt or the like, if necessary.

Further, in the method for polymerizing the copolymer latex according to the present invention, in the first charging stage, the total amount of the ethylenically unsaturated dicarboxylic acid and methacrylic acid in the ethylenically unsaturated carboxylic acid is contained, and a single amount is contained. It is characterized in that 40% by weight or less of the total amount of the body mixture is charged into the polymerization reactor by batch addition and emulsion polymerization is carried out to obtain a desired copolymer latex.

That is, in the first charging stage, the total amount of the ethylenically unsaturated dicarboxylic acid and methacrylic acid in the ethylenically unsaturated carboxylic acid is contained, and the amount of 40% by weight or less of the total amount of the monomer mixture is used in the polymerization reaction. Coated paper which is prepared by adding all at once into a container and carrying out a polymerization reaction to prepare a coating composition in which a copolymer latex is blended as an adhesive is found especially in conventional copolymer latex. It has been found that it is possible to provide a coated paper having a good balance of surface strength and blister resistance, and excellent printability. In addition, in the first charging stage, the total amount of the ethylenically unsaturated carboxylic acid is 5 to 5%.
It is desirable to add 40% by weight to the polymerization reaction vessel by batch addition. Further, as the emulsion polymerization method, a divided addition method in which the second step to the final step are divided and added in a plurality of steps, a continuous addition method in which the second step to the final step are continuously added, or a combination thereof is used. Either is fine.

In the present invention, the polymerization conversion rate during the production of the copolymer latex is preferably about 90% by weight or more, more preferably about 95% by weight or more.

The particle size of the specific copolymer latex used in the present invention is about 50 to 200 nm, and the gel content (indicated by toluene insoluble content) is 20 to 70% by weight, preferably 40. Finishing in the range of up to 69% by weight is desirable for obtaining the effect desired by the present invention. Incidentally, if the gel content is out of the above range, it is difficult to obtain a coated paper in which the desired properties of the present invention such as surface strength, water resistance, ink inking property, blister resistance and the like are balanced. Become.

The blending amount of the above-mentioned copolymer latex in the coating composition (hereinafter, simply referred to as paint) is
The amount is in the range of 1 to 30 parts by weight, preferably 2 to 25 parts by weight, based on 100 parts by weight of the pigment.

Next, the pigment which is one of the components of the coating material is not particularly limited, and generally known pigments used in the field of producing coated paper for printing, such as kaolin,
Delaminated kaolin, calcined kaolin, talc, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, satin white, titanium dioxide, zinc oxide, amorphous silica, zeolite, calcium sulfate, pyrophyllite clay, plastic pigment, etc. Named
One or more of these pigments are used as appropriate.

As the adhesive which is one of the components of the coating material, in addition to the copolymer latex specified above, for example, styrene / acrylic type, ethylene / vinyl acetate type, butadiene / methyl methacrylic type, acetic acid Various copolymer latex such as vinyl / butyl acrylate, and alkali sensitive or non-sensitive adhesive such as polyvinyl acetate,
Furthermore, polyvinyl alcohol, styrene copolymers, maleic anhydride copolymers, synthetic adhesives such as acrylic acid / methyl methacrylate copolymers, starches such as oxidized starch, esterified starch, etherified starch, enzyme-modified starch, etc. . Examples include cold water-soluble starch obtained by flash-drying them, natural adhesives such as casein and soybean protein, and the like. The blending amount of these adhesives is adjusted within the range of 1 to 20 parts by weight with respect to 100 parts by weight of all pigments.

If necessary, various auxiliary agents such as a dispersant, a thickener, a water retention agent, a defoaming agent, a lubricant, a dye, and a pH adjusting agent may be appropriately added to the coating material. When preparing the coating composition, a mixing stirrer such as a choles mixer, a kneader, or a ball mill is appropriately used so that the solid content is 50 to 70% by weight.
Is prepared as an aqueous paint. The coating material thus prepared is a coating machine generally used in the coated paper manufacturing field, for example, an air knife coater, a roll coater, or a paddle or inverter type bevel or bend type blade coater, a bill blade, a twin blade, Blade coater such as Chanplex coater, Bali bar coater, short dwell coater,
Using a bar coater, etc., the tsubo is about 30-400 g / m
^{About 2} or about ^{2 of the} base paper for coated paper is coated in one layer or in multiple layers so that the coated amount after drying is about 3 to 40 g / m ² .

The base paper for coated paper is not particularly limited, and acidic paper or neutral paper generally used in the field of coated paper for printing is applied. If necessary, a general pigment paint may be pre-coated on one side or both sides of the base paper. In this case, the coating amount is preferably about 1 to ²⁰ g / m ² in terms of dry weight per side. If necessary, the base paper or this pre-coated paper may be subjected to smoothing treatment such as super calendering, soft calendering or brushing in advance.

The coated paper thus obtained is usually passed through a finishing device such as a super calender, a gloss calender or a mat calender to impart smoothness to the coated layer surface for off-wheel printing. Finished as coated paper.

[0038]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these. Unless otherwise specified, "part" in the examples
And "%" means "part by weight" and "% by weight", respectively.
Is shown.

Example 1 (Production of Copolymer Latex) 1,3-Butadiene 5 was added to a nitrogen-substituted autoclave as a first stage charge.
Parts, styrene 7 parts, methyl methacrylate 5 parts, acrylamide 1 part, itaconic acid 1 part, methacrylic acid 1 part, potassium persulfate 0.5 part, water 100 parts, sodium alkylbenzene sulfonate 0.1 part and octanoic acid- 0.2 part of 2-mercaptoethyl ester was charged and reacted at 70 ° C. with stirring.

After 2 hours, as the second stage preparation, 1,3
-Butadiene 20 parts, styrene 39.5 parts, methyl methacrylate 10 parts, acrylonitrile 5 parts, acrylic acid-
2-Hydroxyethyl (2.5 parts), acrylic acid (3 parts) and octanoic acid-2-mercaptoethyl ester (0.5 parts) were continuously added together with 0.5 part of sodium alkylbenzenesulfonate over 5 hours to carry out a reaction.

After the reaction was carried out for 15 hours, when the polymerization conversion reached 95% or more (per 100 parts of the monomer), the obtained reaction mixture was cooled to 30 ° C. and sodium hydroxide was added. PH was adjusted to 7.0 ± 0.2. Then, water vapor was blown into the reaction mixture to remove unreacted monomers, and further concentrated to a solid content concentration of 50% to obtain a target copolymer latex.

(Production of Coated Paper) Next, the following coating materials were prepared using the copolymer latex thus obtained. That is, 70 parts of kaolin (trade name: Ultra White-90 / Engelhard), 30 parts of heavy calcium carbonate (trade name: Carbital-90 / ECC), sodium polyacrylate (trade name: Aron T)
-40 / 0.1 part of Toagosei Chemical Industry Co., Ltd., 14 parts of the copolymer latex obtained above (solid content), and 3 parts of modified starch MS-4600 (manufactured by Nippon Shokubai Co., Ltd.),
Mix and stir each, and add water to obtain a solid concentration of 60%
A paint was prepared. Coated Thus paint obtained in basis weight 75 g / m ² of web offset printing coated onto base paper, both surfaces with a blade coater so laydown after drying per one side is 15 g / m ² After covering, it was dried with an air floating dryer to obtain a coated paper for offset printing.

The coated paper thus obtained was subjected to a linear pressure of 100.
Super calendering was performed under the conditions of kg / cm and roll temperature of 70 ° C. The quality characteristics of the coated paper thus obtained were measured, and the results are shown in Table 4.

Examples 2 to 11 Emulsion polymerization was carried out in the same manner as in Example 1 except that the polymerization was carried out with the monomer composition, the polymerization chain transfer agent composition and the polymerization initiator composition shown in Tables 1 and 2. A coating material was prepared in the same manner as in Example 1 except that a polymer latex was produced and the copolymer latex portion was changed, and a coated paper was obtained using the coating material. The quality characteristics of each coated paper thus obtained were measured, and the results are shown in Table 4.

Comparative Examples 1 to 5 Emulsion polymerization was carried out in the same manner as in Example 1 except that the monomer composition, the polymerization chain transfer agent composition and the polymerization initiator composition shown in Table 3 were used for the copolymer latex. Was prepared, and a coating material was prepared in the same manner as in Example 1 except that the copolymer latex portion was changed, and a coated paper was obtained using the coating material. The quality characteristics of each coated paper thus obtained were measured, and the results are shown in Table 4.

Examples 12 to 22 and Comparative Examples 6 to 10 Using the copolymer latexes obtained in Examples 1 to 11 and Comparative Examples 1 to 5, undercoat paints having the following compositions were prepared. That is, Kaolin (trade name: Ultra White-90
/ Engelhard) 20 parts, heavy calcium carbonate (trade name: Carbital-90 / ECC) 80
Part, sodium polyacrylate (trade name: Aron T-40 /
0.1 part by Toagosei Co., Ltd., 3 parts (solid content) of the copolymer latex obtained above, modified starch MS-4
8 parts of 600 (Nippon Shokuhin Kako Co., Ltd.) were mixed and stirred, and water was added to prepare a coating material having a solid content concentration of 60%.

The undercoat paint thus obtained was coated on a base paper for off-wheel printing having a basis weight of 75 g / m ² with 9 g per side.
So that / m ^2, coated on both sides with a blade coater,
It was dried to obtain an undercoated paper.

Then, on each of the undercoated papers thus obtained, the coating materials obtained in Examples 1 to 11 and Comparative Examples 1 to 5 were applied as a top coating material in such a manner that the coating amount was 8 g / m ^{2 on each} side. Was coated on both sides and dried to obtain a double-sided coated paper with double coating on one side. The coated paper thus obtained was subjected to a super calender treatment under the conditions of a linear pressure of 100 kg / cm and a roll temperature of 70 ° C. The quality characteristics of the coated paper obtained were measured, and the results are shown in Table 5.

The quality characteristics in Tables 4 and 5 are as follows:
The evaluation was carried out as follows. (1) Toluene-insoluble matter (gel content) Copolymer latex was poured into a glass mold to a thickness of 0.
Make a 3 mm film. This film is 2-3m
Cut into m squares and weigh 0.4 g precisely. The sample is 100m
It is immersed in 1 l of toluene and shaken in a shaking constant temperature bath at 30 ° C. for 6 hours. Then, filter with 100 mesh wire mesh,
The solid content of the filtrate was determined, and the gel content was calculated from this sol solid content.

(2) Surface Strength (Dry Pick) Using a RI tester (Myo Seisakusho), tack no. Overprinting was performed several times with the red ink of No. 13, and the picking state of the printed surface was visually judged and evaluated according to the following criteria. ◎: No picking at all. ○: Picking is slightly observed. Δ: Picking is observed, but printable surface strength. X: Picking is remarkably observed and printing is impossible.

(3) Water resistance (wet pick) Using a RI tester, the surface of the test piece was wetted with water using a molton roll. Printing was performed with the red ink of No. 13, and the picked state of the printed surface was visually judged and evaluated according to the following criteria. ◎: No picking at all. ○: Picking is slightly observed. Δ: Picking is observed, but printable surface strength. X: Picking is remarkably observed and printing is impossible.

(4) Ink ink receptivity Ink is printed by the same method as water resistance, but has a lower tack value than in water resistance measurement (New Champion F-GLOSS / Dainippon Ink and Chemicals). Was used to prevent picking, and the state of ink transfer was visually compared and evaluated, and evaluated according to the following criteria. ⊚: Very good ink receptivity. ○: Ink receptivity is good. Δ: Ink receptivity is poor.

(5) Suitability for Blister Using a Komori off-wheel printing machine (System C-20),
Ink for web offset ink (Web World
d Luster H Type / manufactured by Dainippon Ink Kogyo Co., Ltd., and printing was performed at a printing speed of 200 rpm, and the temperature at which blister was generated was examined (the lower the temperature, the poorer the blister resistance).

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

[0057]

[Table 4]

[0058]

[Table 5]

[0059]

As is clear from the results of Tables 4 to 5,
The coated paper for off-ring printing obtained in the examples of the present invention had a very good balance in surface strength, water resistance, ink receptivity and blister resistance.

Claims (5)

[Claims] 1. A coated paper for off-ring printing, which comprises coating a base paper with a coating composition containing a pigment and an adhesive as main components and drying the coated paper, wherein the adhesive is (1) a conjugated diene-based monolithic paper. In emulsion-polymerizing a monomer mixture containing a monomer, (2) an ethylenically unsaturated carboxylic acid, and (3) an ethylenically unsaturated monomer other than (2), in the first charging stage, (2) Of the ethylenically unsaturated carboxylic acids, the total amount of the ethylenically unsaturated dicarboxylic acid and methacrylic acid is contained, and 40% by weight or less of the total amount of the monomer mixture is charged into the polymerization reactor by batch addition to carry out emulsion polymerization. A coated latex for off-wheel printing, characterized in that it is a copolymer latex obtained by performing the above step, and the copolymer latex is blended in an amount of 1 to 30 parts by weight with respect to 100 parts by weight of the pigment. 2. The monomer composition constituting the copolymer latex is (1) 20 to 50% by weight of a conjugated diene monomer, (2)
0.2 to 12% by weight of ethylenically unsaturated carboxylic acid, and 50 to 7 of ethylenically unsaturated monomer other than (3) and (2)
The coated paper for offset printing according to claim 1, which comprises 9.8% by weight. 3. The coated paper for off-wheel printing according to claim 1, wherein the conjugated diene monomer is 1,3-butadiene. 4. The coated paper for offset printing according to claim 1, wherein the copolymer latex has an average particle diameter of 50 to 200 nm. 5. The coated paper for offset printing according to claim 4, wherein the copolymer latex has a gel content of 20 to 70% by weight.