JP2000110093A - Composition used for coated paper for gravure printing and coated paper for gravure printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coated paper for gravure printing, excellent in white paper gross, opacity, surface strength and anti-blocking property, and less generating missing dots, and a composition used for production of such coated paper for gravure printing. SOLUTION: This coated paper for gravure printing is obtained by coating a composition used for the coated paper for gravure printing, which contains a pigment, hollow polymer particles and a copolymer latex having 0.06-0.2 μm number-average particle diameter as an adhesive, in which the tetrahydrofuran un-dissolvable fraction of the copolymer constituting the copolymer latex is 60-90 wt.% and the glass transition temperature thereof is (-)25-(+)30 deg.C, over a raw material paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for coated paper for gravure printing and a coated paper for gravure printing. More specifically, the present invention relates to a composition for coated paper for gravure printing containing a pigment, hollow polymer particles and a specific copolymer latex as an adhesive, and a coated paper for gravure printing obtained by applying the composition to base paper.

[0002]

2. Description of the Related Art In recent years, gravure printing, which has a high ink density and can provide colorful printed matter, is often used for printing coated paper. Coated paper used for gravure printing is required not only to have excellent white paper gloss, opacity, surface strength, and blocking resistance, but also to be free from missing dots. Conventionally, in order to obtain a coated paper with less occurrence of missing dots, a method of using a copolymer having a glass transition temperature of −40 ° C. or less as an adhesive, and further performing a surface treatment under high temperature and high pressure using a calendar. Was used. However, the coated paper for gravure printing obtained by this method was inferior in opacity, surface strength and blocking resistance. The conventional coated paper having poor blocking resistance had a large amount of deposits on the calendar roll. Adhered matter causes problems such as damaging the roll and dents or scratches on the coated paper. Therefore, in the conventional method, the roll is frequently cleaned.

As another method for providing a coated paper with less occurrence of missing dots, a method using hollow polymer particles as a pigment has been proposed. JP-A-64-20
No. 396 discloses a pigment having an outer diameter of 0.2 to 0.6.
2-20 non-film-forming resin particles having voids inside
A gravure coated paper coated with a composition containing by weight is disclosed. Further, the publication discloses that a combination of an alkali-sensitive resin emulsion or an alkali-insensitive resin emulsion and a thickener is used as an adhesive. However, since this adhesive requires the use of a thickener, the viscosity of the coating composition becomes high, and the transfer of the coating composition is not easy, and the control of the coating amount is difficult. was there.

Japanese Patent Application Laid-Open No. Hei 5-125695 discloses a coating for gravure printing in which a specific base paper is provided with a coating layer containing 5 to 40% by weight of 0.8 to 6 μm hollow polymer particles as a pigment. Papermaking is disclosed. In this method, it is necessary to use a base paper containing 10 to 50% by weight of a filler. However, when base paper containing a large amount of filler is used, there has been a problem that paper peeling easily occurs during printing.

[0005] Coating paper for gravure printing with less occurrence of missing dots has been obtained by the above method using hollow polymer particles and the like. However,
These methods have failed to provide a coated paper for gravure printing which has excellent white paper gloss, opacity, surface strength, and blocking resistance, and generates few missing dots.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a coated paper for gravure printing which is excellent in white paper gloss, opacity, surface strength, and blocking resistance, and has little occurrence of missing dots. And to provide a composition used for the production of such a coated paper.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventor has conducted studies on adhesives. As a result, tetrahydrofuran insoluble components having a number average particle diameter in a specific range are obtained. By using a latex of a copolymer having a glass transition temperature in a specific range, it was found that an intended coated paper for gravure printing could be obtained, and based on this finding, the present invention was completed.

Thus, according to the present invention, an adhesive comprising a pigment, hollow polymer particles, and a copolymer latex having a number average particle diameter of 0.06 to 0.2 μm is contained. The copolymer has a tetrahydrofuran insoluble content of 60 to 90% by weight and a glass transition temperature of -2.
A composition for coated paper for gravure printing characterized by a temperature of 5 to + 30 ° C., and a coated paper for gravure printing obtained by applying the above composition to base paper are provided.

Hereinafter, the present invention will be described in detail. The composition for coated paper for gravure printing of the present invention (hereinafter referred to as “coating composition”) comprises a pigment, hollow polymer particles and a copolymer latex.

The pigment used in the present invention is not particularly limited. Examples of the pigment include clay, calcium carbonate, titanium oxide, aluminum hydroxide, satin white, silica, talc,
Inorganic pigments such as barium sulfate; plastic pigments,
Organic pigments such as a binder pigment are exemplified. These can be used alone or in combination of two or more.

The hollow polymer particles used in the present invention are polymer particles having one or more voids (hollows) inside the particles. The hollow polymer particles preferably have a thermoplastic resin as a shell in order to reduce the occurrence of missing dots.

Examples of hollow polymer particles having a thermoplastic resin as a shell include styrene resins such as polystyrene and poly-β-methylstyrene; polymethyl methacrylate, polyethyl methacrylate, polyisopropyl methacrylate, and polyisobutyl methacrylate. , Acrylic resins such as polyacrylonitrile and polymethacrylonitrile; polyvinyl chloride, polytetrafluoroethylene, polyvinyl alcohol, poly-o-vinylbenzyl alcohol, poly-m-
Vinyl benzyl alcohol, poly-p-vinyl benzyl alcohol, polyvinyl formal, polyvinyl acetal, polyvinyl propional, polyvinyl butyral, polyvinyl isobutyral, polyvinyl tertiary butyl ether, polyvinyl pyrrolidone, polyvinyl carbazole, cellulose acetate, cellulose triacetate, polycarbonate, etc. Various things can be illustrated. Further, those having a shell made of a copolymer or the like obtained by variously combining monomers used for each of the above polymers can also be used. The hollow polymer particles having these thermoplastic resins as shells are not limited by the production method.

[0013] Further, these resins are preferably hollow polymer particles having a multilayer structure because they can obtain a high porosity. Among them, polystyrene-based polymer particles / poly (meth) acrylate-based polymer are preferred. Hollow polymer particles forming a multilayer structure are particularly preferred.

The outer diameter of the hollow polymer particles used in the present invention is:
Although not particularly limited, 0.3 to 10 μm is preferable,
0.5-8 μm is more preferred.

The porosity of the hollow polymer particles used in the present invention (the ratio of the internal void volume to the total particle volume) is not particularly limited, but is at least 10%, preferably at least 30%. It is considered that the larger the porosity, the more easily the coated paper is smoothened by the calendering treatment, so that the occurrence of missing dots is reduced. However, it is actually difficult to produce hollow polymer particles having a porosity of 90% or more.

The hollow polymer particles used in the present invention are not limited by the production method. Examples of the method for producing hollow polymer particles include those described in JP-A-64-1704, JP-A-5-279409, JP-A-6-248012, and JP-A-10-11018. Is mentioned.

The amount of the hollow polymer particles used in the present invention is 0.1 to 30 parts by weight, preferably 0.5 to 25 parts by weight, more preferably 1 to 20 parts by weight based on 100 parts by weight of the pigment. is there. If the amount is less than 0.1 part by weight, the glossiness and opacity of the coated paper are reduced, and more missing dots are generated. If the amount exceeds 30 parts by weight, the viscosity of the composition may increase, or the surface strength of the coated paper may decrease.
If the solid content concentration is lowered to lower the viscosity of the composition, mist is generated at the time of coating, and the coated paper tends to be insufficiently dried.

The adhesive used in the present invention comprises a copolymer latex. The number average particle size of the copolymer latex is
0.06 to 0.2 μm, preferably 0.07 to 0.18
μm, and more preferably 0.08 to 0.15 μm.
If it is less than 0.06 μm, the glossiness of the coated paper is reduced and the occurrence of missing dots is increased. If it exceeds 0.2 μm, the surface strength of the coated paper decreases.

In the present invention, it is necessary that the copolymer constituting the copolymer latex has a tetrahydrofuran insoluble content (hereinafter referred to as "THF insoluble content") of 60 to 90% by weight. Preferably it is 65 to 85% by weight, more preferably 70 to 85% by weight. If the amount is less than 60% by weight, the surface strength of the coated paper is inferior, and further, the blocking resistance in the calendering treatment is inferior.
If it exceeds 90% by weight, the surface strength of the coated paper is inferior,
Many missing dots are generated.

In the present invention, the copolymer constituting the copolymer latex must have a glass transition temperature (hereinafter referred to as "Tg") of -25 to + 30 ° C. Preferably -20 to + 30 ° C, more preferably -1.
5 to + 25 ° C. If the temperature is lower than −25 ° C., the surface strength of the coated paper decreases, and the blocking resistance further decreases. +3
When the temperature exceeds 0 ° C., the surface strength of the coated paper is inferior, and the occurrence of missing dots increases.

The copolymer latex used in the present invention is not particularly limited as long as the number average particle diameter, THF insoluble content, and Tg are within the above ranges, respectively. Specific examples of the copolymer latex include acrylonitrile-butadiene copolymer latex, styrene-butadiene copolymer latex, carboxy-modified styrene-butadiene copolymer latex, styrene-butadiene- (meth) acrylate copolymer latex Conjugated diene copolymer latex such as carboxy-modified styrene-butadiene- (meth) acrylate copolymer latex;
(Meth) acrylate copolymer latex such as (meth) acrylate copolymer latex, styrene- (meth) acrylate copolymer latex, vinyl acetate- (meth) acrylate copolymer latex Is mentioned.

Among the above copolymers, styrene-butadiene copolymer latex, especially carboxy-modified styrene-butadiene copolymer latex, especially conjugated diene monomer, aromatic vinyl monomer, ethylenically unsaturated monomer A copolymer latex obtained by copolymerizing a carboxylic acid monomer and, if necessary, a monomer copolymerizable therewith is preferably used.

As the conjugated diene monomer, for example,
1,3-butadiene, isoprene, 2,3-dimethyl-
Examples thereof include 1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and chloroprene. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, β-methylstyrene, o-
Vinyltoluene, m-vinyltoluene, p-vinyltoluene, o-chlorostyrene, m-chlorostyrene, p-
Chlorostyrene, hydroxymethylstyrene, halogenated styrene and the like can be mentioned. Examples of the ethylenically unsaturated carboxylic acid monomer include, for example, acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, mono- or dicarboxylic acids such as itaconic acid, anhydrides of dicarboxylic acids,
And monoalkyl esters of dicarboxylic acids. Examples of the monomer copolymerizable with the monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, 2-ethylhexyl acrylate, glycidyl (meth) acrylate, and lauryl (meth) acrylate. Ethylenically unsaturated carboxylic acid ester monomers such as acrylate; ethylenically unsaturated carboxylic acid amide monomers such as (meth) acrylamide and N-methylol (meth) acrylamide; (meth) acrylonitrile, fumaronitrile, 2- Ethylenically unsaturated nitrile monomers such as chloropropenenitrile, 2-ethylpropenenitrile, 2-propylpropenenitrile and 2-butenenitrile; divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate What crosslinkable monomer, ethylene, and vinyl acetate.

The amount of the copolymer latex used as the adhesive in the present invention is 2 to 30 parts by weight, preferably 3 to 25 parts by weight, more preferably 3 to 25 parts by weight, based on 100 parts by weight of the pigment. 20 parts by weight. If the amount is less than 2 parts by weight, the surface strength of the coated paper is insufficient, and the printed surface is peeled off. If the amount is more than 30 parts by weight, the smoothness is hardly improved even by calendering, so that the glossiness of the coated paper is reduced, and more missing dots are generated.

In the coating composition of the present invention, if necessary, auxiliary materials such as dyes, dispersants, pH adjusters, lubricants, mold release agents, viscosity adjusters, defoamers, preservatives, etc. Can be blended. The types of these auxiliary materials are not particularly limited. Further, the usage amount, addition concentration, addition method, and the like of these auxiliary materials can be arbitrarily selected within a range that does not impair the effects of the present invention.

The solid content of the coating composition of the present invention is not particularly limited, but is usually 20 to 70% by weight, preferably 30 to 65% by weight. If it is less than 10% by weight, mist is generated at the time of coating, or the coated paper tends to be insufficiently dried. If it exceeds 70% by weight, the fluidity of the coating composition will decrease, making it difficult to adjust the coating amount.

In the method for preparing the coating composition of the present invention, generally, a pigment, a hollow polymer particle, a copolymer latex, water and, if necessary, auxiliary materials are added to a dispersing machine. And stirred to prepare.

The coated paper for gravure printing of the present invention is obtained by coating the above-mentioned coating composition of the present invention on one or both sides of a base paper and then drying it.

The basis weight of the base paper used for producing the coated paper for gravure printing of the present invention is not particularly limited.
200 g / ^{m 2,} preferably 30~160g / ^{m 2.}

In order to obtain the coated paper for gravure printing of the present invention, the base paper is coated with the coating composition of the present invention in an amount of 3 to 3 per side.
Apply 20 g / m ² (dry weight).

The coating method is not particularly limited, but is usually performed using a coating machine such as a gate roll coater, blade coater, bill blade coater, bar coater, curtain coater, air knife coater, or the like.

The method of drying after coating is not particularly limited, but is usually carried out using a dryer such as a steam dryer, a hot air dryer or an electric heater dryer. The drying temperature and drying time vary depending on the dryer and the coating speed, but are usually from 80 to 1
At 80 ° C., the time is about 0.03 to 10 seconds.

After coating and drying the coating composition of the present invention on base paper, the coated paper is subjected to calendering using various calendars such as a super calender, a gloss calender, a soft calender, and a machine calender. Can be. The roll temperature and the linear pressure of the calender are not particularly limited, but usually the roll temperature is about 40 to 200 ° C and the linear pressure is about 60 to 200 kg / cm.

[0034]

The present invention will be described below in more detail with reference to Examples, Comparative Examples and Reference Examples. In the Examples, Comparative Examples and Reference Examples, parts and% are based on weight, and the weight of the copolymer latex is in terms of solid content. [Evaluation Method of Copolymer Latex] The method of measuring the number average particle diameter of the copolymer latex, and the THF-insoluble content and Tg of the copolymer constituting the copolymer latex are as follows.

(Number average particle diameter) The copolymer latex whose pH has been adjusted to 8 is measured using COULTER LS230 (manufactured by Coulter KK).

(THF insoluble content) A copolymer latex of pH 8 was cast on a glass plate held horizontally so that the thickness of the dried film was about 2 mm.
Dry naturally for 48 hours in a constant temperature and humidity room maintained at 65 ° C. and a humidity of 65%. The obtained film was peeled off from the glass plate and cut into 2 mm x 2 mm, and about 0.3 g of the film was cut into a box-shaped 80 mm.
It is precisely weighed (weight: Bg) and put into a mesh wire net (weight: Ag). This box-shaped 80 mesh wire mesh is put into a glass beaker, 100 ml of tetrahydrofuran (THF) is poured therein, and the mixture is left at room temperature for 48 hours. Thereafter, the wire net is pulled up, placed on an aluminum plate (weight: Cg) weighed in advance, and left in a draft for 4 hours. Thereafter, the entire aluminum plate is dried in a dryer at 105 ° C. for 3 hours, and the dry weight (weight: Dg) of the entire aluminum plate is measured.
The THF insoluble content is calculated by the following equation. THF-insoluble content (%) = (DCA) × 100 / B

(Tg) A copolymer latex having a pH of 8 was cast on a glass plate held horizontally so that the thickness of the dried film was about 2 mm, and the temperature was 23 ° C. and the humidity was 65%.
Dry naturally for 48 hours in a constant temperature and humidity room kept at a constant temperature. Peel off the obtained film from the glass plate, 2mm × 2mm
Then, cut about 10 mg in a special container and cover it. The dedicated container was set on a differential scanning calorimeter (Model RDC220, manufactured by Seiko Electronics Co., Ltd.), and the initial temperature was set at -8.
The measurement is performed under the conditions of 0 ° C., end temperature of 80 ° C., and heating rate of 10 ° C./min.

[Evaluation Method of Coated Paper] The evaluation methods of the white paper gloss, opacity, surface strength, number of missing dots and blocking resistance of the coated papers of the examples and comparative examples are as follows.

(Blank gloss) Using a gloss meter (manufactured by Murakami Color Research Laboratory: GM-26D), an incident angle of 75 degrees was used.
It is measured at a reflection angle of 75 degrees (unit:%). The higher the value, the better the blank gloss.

(Opacity) Measured using a spectral color whiteness meter PF10 (manufactured by Nippon Denshoku Industries Co., Ltd.) (unit:%). The higher the value, the better the opacity.

(Surface Strength) Using a RI printing suitability tester (manufactured by Ishikawajima-Harima Heavy Industries, Ltd.), the coated paper was overprinted four times with picking ink (tack value: 14; manufactured by Toyo Ink Co., Ltd.). Is visually determined and indicated by a five-point method. The higher the score, the better the surface strength.

(Number of missing dots) Using a gravure printing suitability tester (manufactured by Kumagaya Riki Kogyo Co., Ltd.)
Printing is performed on coated paper under the following conditions, and the number of missing dots in the 30% gradation portion is counted. The ink used was No. 1 with the addition of xylene to Toyo Ink OGH91 black ink. Adjust for 3 seconds with 30 seconds. Printing pressure of 12 kg / cm ²
And the printing speed is 70 m / min.

(Blocking resistance) The coating composition was applied to one surface of a commercially available medium base paper having a basis weight of 48 g / m ² using a wire bar so that the coating amount after drying was 10 g / m ^2. After coating, it is dried in a hot air dryer at 100 ° C. for 10 seconds. After drying, take out the coated paper, temperature 23 ℃, humidity 65
%, And the coated paper is cut into a width of 3 cm and a length of 20 cm to obtain a test piece. On the coated surface of this test piece, width 2.5 cm, length 25 c
m polyethylene film, 120 ° C, 3 kg using a heat sealer (manufactured by Tester Sangyo Co., Ltd.)
/ Cm ² for 30 seconds. After crimping, it is taken out of the heat sealer and left at room temperature for 3 minutes while being crimped. After standing for 3 minutes, the polyethylene film was peeled off from the test piece, and the amount of the adhered substance on the polyethylene film was visually determined and indicated by a 5-point method. Standard of 5-point method: 5 points with no deposits, 4 points with slight deposits, 3 points with slight deposits, 2 points with many deposits, extremely large number of deposits One point. The higher the score, the better the blocking resistance.

Reference Example 1 Production of Copolymer Latexes (A) to (H) 50 parts of water was placed in a pressure-resistant vessel equipped with a stirrer, the inside of which was replaced with nitrogen.
0.5 part of sodium bicarbonate, 0.2 part of sodium lauryl sulfate, the monomers shown in Table 1, and t-dodecyl mercaptan were charged and stirred for 30 minutes to prepare a monomer emulsion. An autoclave equipped with a stirrer and a temperature sensor, the inside of which was replaced with nitrogen, was charged with 0.05 parts of sodium ethylenediaminetetraacetate, 0.5 parts of potassium persulfate and 5 parts of water.
0 parts and sodium lauryl sulfate shown in Table 1 were charged, and the internal temperature was adjusted to 80 ° C. 8% of the monomer emulsion was added to an autoclave and reacted for 1 hour. The remaining monomer emulsion and 0.5 part of potassium persulfate were each added continuously over 5 hours. After completion of the addition, the internal temperature was set to 85 ° C., and the reaction was completed by maintaining the temperature for 4 hours. The polymerization conversion of each of the obtained copolymer latexes was 98% or more. After adding a 20% aqueous solution of sodium hydroxide to each of the obtained copolymer latexes to adjust the pH to 8, unreacted monomers were removed with a rotary evaporator. After further concentration, aggregates in the copolymer latex were removed using a 325 mesh wire mesh, and the solid content concentration was 50%.
A copolymer latex having a pH of 8 was obtained. Using each of the obtained copolymer latexes, the number average particle diameter, THF-insoluble content and Tg of the copolymer latex were measured and are shown in Table 1.

[0045]

[Table 1]

[Production of Coated Paper for Gravure Printing] Example 1 In a dispersing machine, 100 parts of clay (Hydrasperse, manufactured by Huber), 0.3 parts of sodium polyacrylate, 0.15 parts of sodium hydroxide were used. Polymer latex (A) 8
Parts, 5 parts of hollow polymer particles (HP-1055: manufactured by Rohm & Haas Co., Ltd.), 0.7 parts of a release agent (Nopcoat C104HS, manufactured by San Nopco) and 70 parts of water, and stirred for 30 minutes to obtain a solid content. A coating composition having a concentration of 62% was obtained.

This coating composition was applied onto a commercially available medium base paper having a basis weight of 48 g / m ² , and the coating amount after drying on one side was 10 g / m 2.
After coating using a wire bar so that it becomes ² , 10
It was dried in a hot air dryer at 0 ° C. for 10 seconds. Further, the other side was coated and dried in the same manner as above to obtain a coated paper. The obtained coated paper was heated at a temperature of 23 ° C and a humidity of 65.
% For 5 hours in a constant temperature / humidity room. The coated paper is coated on a metal roll at a surface temperature of 40 ° C. and a linear pressure of 75 kg / cm.
The surface treatment was performed twice with the experimental mini super calender adjusted to obtain coated paper (1). The coated paper (1) was measured for white paper gloss, opacity, surface strength, number of missing dots, and blocking resistance. Table 2 shows the results.

Examples 2 to 5 Coated papers (2) to (5) were prepared in the same manner as in Example 1 except that the copolymer latexes (B) to (E) were used instead of the copolymer latex (A). ) Got. Coated paper (2)-
Physical properties of (5) were measured as in Example 1. Table 2 shows the results. .

Example 6 A composition having a solid content of 62% was obtained in the same manner as in Example 1 except that the amount of the hollow polymer particles was changed to 10 parts and the amount of water was changed. A coated paper (6) was obtained in the same manner as in Example 1 using this composition. The physical properties of the coated paper (6) were measured in the same manner as in Example 1. Table 2 shows the results.

Comparative Examples 1 to 6 Coated papers (7) to (12) were prepared in the same manner as in Example 1 except that copolymer latexes (F) to (K) were used instead of copolymer latex (A). ) Got. Coated paper (7)-
Physical properties of (12) were measured in the same manner as in Example 1. Table 2 shows the results.

[0051]

[Table 2]

From Table 2, it can be seen that coated paper using a copolymer latex having a small number average particle diameter as an adhesive (Comparative Example 1)
Indicates that the gloss of the white paper is inferior and that the occurrence of missing dots is large. It can be seen that the coated paper using the copolymer latex having a large number average particle diameter as an adhesive (Comparative Example 2) has poor surface strength. In addition, it can be seen that the coated paper (Comparative Example 3) using a copolymer latex having a low THF insoluble content as an adhesive is inferior in white paper gloss, surface strength and blocking resistance. It can be seen that the coated paper (Comparative Example 4) using a copolymer latex having a high THF-insoluble content as an adhesive had poor white paper gloss and surface strength, and generated many missing dots. Furthermore, it can be seen that the coated paper using the copolymer latex having a low Tg as an adhesive (Comparative Example 5) has poor surface strength and blocking resistance. It can be seen that the coated paper using the copolymer latex having a high Tg as an adhesive (Comparative Example 6) is inferior in white paper gloss and surface strength, and generates many missing dots.
Compared with the coated papers of Comparative Examples 1 to 6, it can be seen that the coated paper for gravure printing of the present invention is excellent in white paper gloss, opacity, surface strength and blocking resistance, and generates few missing dots.

[0053]

EFFECT OF THE INVENTION By using the composition for coated paper for gravure printing of the present invention, a coated paper for gravure printing which is excellent in white paper gloss, opacity, surface strength and blocking resistance and in which few missing dots are generated. Can be provided.

Preferred Embodiments of the Invention Embodiments of the present invention are summarized below. (1) Pigment, hollow polymer particles, and a copolymer latex having a number average particle diameter of 0.06 to 0.2 μm as an adhesive, and tetrahydrofuran insoluble in the copolymer constituting the copolymer latex A composition for coated paper for gravure printing, wherein the composition has an amount of 60 to 90% by weight and a glass transition temperature of -25 to + 30 ° C. (2) The composition for coated paper for gravure printing according to (1), wherein the outer diameter of the hollow polymer particles is 0.3 to 10 μm, preferably 0.5 to 8 μm. (3) The porosity of the hollow polymer particles (the ratio of the internal void volume to the total particle volume) is 10% or more, and preferably 30% or more.
% Or more of the composition for coated paper for gravure printing according to (1) or (2). (4) The amount of the hollow polymer particles used is 0.1 to 30 parts by weight, preferably 0.5 to 25 parts by weight, based on 100 parts by weight of the pigment.
Parts by weight, more preferably 1 to 20 parts by weight (1) to
The composition for coated paper for gravure printing according to any one of (3).

(5) The copolymer latex according to any one of (1) to (4), wherein the number average particle diameter is preferably 0.07 to 0.18 μm, more preferably 0.08 to 0.15 μm. A composition for a coated paper for gravure printing according to the above. (6) The tetrahydrofuran-insoluble content of the copolymer is preferably 65 to 85% by weight, more preferably 70 to 85% by weight.
The composition for coated paper for gravure printing according to any one of (1) to (5), which is a percentage by weight. (7) The glass transition temperature of the copolymer is preferably -20
The composition for coated paper for gravure printing according to any one of (1) to (6), wherein the composition has a temperature of from to + 30 ° C, more preferably from -15 to + 25 ° C. (8) The composition for coated paper for gravure printing according to any one of (1) to (7), wherein the copolymer latex is a styrene-butadiene copolymer latex or a carboxy-modified styrene-butadiene copolymer latex. . (9) The amount of the copolymer latex to be used is 2 to 30 parts by weight, preferably 3 to 25 parts by weight, more preferably 3 to 20 parts by weight, in terms of solid content, based on 100 parts by weight of the pigment ( The composition for a coated paper for gravure printing according to any one of 1) to (9).

(10) Coated paper for gravure printing obtained by applying the composition of (1) to (9) to base paper. (11) The coated paper for gravure printing according to (10), wherein the basis weight of the base paper is 20 to 200 g / m ² , preferably 30 to 160 g / m ² . (12) The base paper is coated with the composition of (1) to (9) in an amount of 3
２０20 g / m ² (dry weight).
The coated paper for gravure printing according to (0) or (11).

Claims (2)

[Claims] 1. A copolymer comprising a pigment, hollow polymer particles, and a copolymer latex having a number average particle diameter of 0.06 to 0.2 μm as an adhesive, and a tetrahydrofuran copolymer constituting the copolymer latex. A composition for coated paper for gravure printing characterized by having an insoluble content of 60 to 90% by weight and a glass transition temperature of -25 to + 30 ° C. 2. A coated paper for gravure printing obtained by coating the composition according to claim 1 on a base paper.