JP3247768B2 - Manufacturing method of coated paper and coated paper obtained by the manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coated paper and a coated paper obtained by the method, and more particularly, to a method in which a paper is coated with a specific coating agent and pressed by a hot roll. The present invention relates to a method for producing a coated paper having excellent printing ink setting property and very high gloss.

[0002]

2. Description of the Related Art Conventionally, in the field of offset printing, paper is mainly used as a printing medium. Among them, coated paper has a smoother printed surface compared to uncoated paper,
It has good printing suitability such as ink acceptability and setting properties, and has the advantage that a glossy and clear printed matter can be produced. Therefore, it has been widely used for producing cosmetic printed matter.

[0003] Coating agents used for producing this coated paper generally include inorganic extender pigments such as kaolin clay, calcium carbonate and titanium dioxide, casein, starch and SB.
R resin, alkali-soluble latex, and other binder resins, which are obtained by mixing them with various coating means such as a roll coater, blade coater or air knife coater. Coated paper is obtained by pressing with a roll.

[0004] The pigments are arranged in layers on the paper surface to smooth the paper surface, absorb the flow components of the offset ink, improve the ink setting property, and have the luster of the pigment itself. This gives gloss to the printed matter.

[0005] On the other hand, the binder resin has the effect of maintaining the fluidity of the coating agent and preventing the pigment from falling off the printing medium and cracking of the coating agent layer.

Therefore, the gloss of the coated paper obtained by using the conventional coating agent depends on the surface gloss and the particle size of the pigment itself.

[0007] In general, the use of fine-particle pigments makes it possible to obtain high-gloss coated paper.
No. 6996 discloses that the primary particle diameter is 0.1 to 1.0 μm.
Of cubic calcium carbonate fine particles of 30
It describes a method for producing cast paper that can maintain high glossiness and can be produced at a high speed by using an inorganic extender pigment containing up to 70% by weight as a pigment of a coating agent.
However, in this method, the gloss of the coated paper decreases as the ratio of the fine particles of calcium carbonate to the total pigment increases.

This is because even if a pigment having a small primary particle diameter is used, the pigment itself forms a strong aggregate,
This is because it is difficult to disperse the particles to the level of the primary particles by a normal production method, and the result is substantially the same as that obtained by using coarse particles.

Japanese Patent Application Laid-Open No. 57-25499 discloses a method for dispersing a pigment to a fine particle diameter.
A method is described in which calcium carbonate having a fine particle diameter of about 1.0 μm is mixed with a starch derivative and subjected to a dispersion treatment with a sand mill to thereby disperse the primary particles.

[0010] However, even if the pigment particles can be reduced to the primary particle level by this treatment, the fluidity of the obtained coating agent is remarkably reduced in the binder resin system used in the ordinary coating agent, Further, gloss higher than the surface gloss of the pigment could not be obtained.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to disperse inorganic extender pigments to the level of primary fine particles, and have good fluidity.
Another object of the present invention is to produce a coated paper having excellent printing ink setting properties and high gloss by using a coating agent capable of imparting high gloss.

[0012]

That is, according to the present invention, a coating agent satisfying the following conditions (a), (b) and (c) is coated on a base paper in an amount of 10 to 40 g / m ² (dry weight). ), Followed by press working using a hot roll heated to 90 to 160 ° C., and a method for producing coated paper.

(A) The solid content of the coating composition is composed of calcium carbonate and other inorganic pigments having an average primary particle size of 0.04 to 1.0 μm, and the weight ratio of both is 30 /
Inorganic extender pigment having an acid value of 50 to 25
0, at least one aqueous binder resin selected from the group consisting of an acrylic resin, a styrene-acrylic resin, a styrene-maleic acid resin, and a styrene-acryl-maleic acid resin having a glass transition temperature of -50 to 120 ° C. It contains.

(B) The weight ratio of the inorganic extender pigment and the aqueous binder resin is 70/30 to 95/5.

(C) The inorganic extender is dispersed by a bead mill or a ball mill.

[0016]

When the inorganic pigment such as calcium carbonate is dispersed using an ordinary stirrer such as a high-speed mixer, since the shear force applied in the system is smaller than the cohesive force of the pigment, the pigment is dispersed to the primary particles. It is difficult.

Further, even if a high shearing force is applied to disperse the primary particles, the average primary particle diameter is 0.04 to 0.04.
In the case of a 1.0 μm fine particle pigment, since the surface area of the pigment is very large, a latex binder resin used in a usual coating agent cannot completely wet the pigment surface, and the obtained coating agent The fluidity is significantly reduced.

Therefore, in order to disperse the fine particle pigment to the primary particle size and maintain good fluidity, it is necessary to use a special disperser and a binder resin.

The aqueous binder resin used in the present invention comprises:
The molecule has a functional group such as a carboxyl group, a hydroxyl group, and an amide group that can be adsorbed on the pigment surface. By mixing these aqueous binder resins and inorganic extender pigments, a bead mill,
When dispersed by a specific dispersing machine such as a ball mill, a high shearing force is applied to the system, and the pigment can be dispersed to primary particles.

Further, since these aqueous binder resins wet the pigment surface well, the fluidity of the obtained coating agent can be improved.

Further, the gloss of coated paper obtained from the conventional coating agent depends on the gloss of the pigment itself contained in the coating agent. Since the binder resin has a good wet glass-like gloss, the gloss of the coated paper becomes very high.

Hereinafter, the present invention will be described in more detail.

First, the inorganic extender pigment used in the coating composition according to the present invention has an average primary particle diameter of 0.04 to 0.04.
1.0 μm calcium carbonate as an essential component,
Among them, more fine particles of 0.04 to 0.50 μm
Those having a cubic crystal structure of m are preferred.

In the present invention, the amount of the calcium carbonate in the above-mentioned specific primary particle size range is 30% by weight or more, more preferably 70% by weight, based on the total inorganic extender pigment.
That is all. 30% by weight of the calcium carbonate used
If it is less than 1, the luster desired in the present invention cannot be obtained, which is not preferable.

As other inorganic extender pigments that can be used in combination, titanium dioxide, kaolin clay, talc and the like can be used. Since the present invention is characterized in that the inorganic extender pigment is dispersed to fine particles, It is desirable that the inorganic extender also has a primary particle diameter of 1.0 μm or less.

Next, the aqueous binder resin used in the present invention includes at least one aqueous resin selected from acrylic resins, styrene-acrylic resins, styrene-maleic acid resins, and styrene-acryl-maleic acid resins. Binder resins can be used.

The respective aqueous binder resins are defined as follows.

The acrylic resin is an aqueous binder resin obtained by copolymerizing an acrylic monomer.

As the acrylic monomer, acrylic acid or methacrylic acid can be used as an essential component, and one or more acrylic acid or methacrylic acid derivatives can be selected and used.

The following monomers can be used as the derivatives of acrylic acid or methacrylic acid.

Alkyl (meth) acrylates Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) acryl Octyl acid, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc. alkyl esters having 1 to 18 carbon atoms (meth) acrylic acid hydroxyalkyl esters (meth) acrylic acid 2- Hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 9- (meth) acrylate Hydroxyalkyls having 2 to 9 carbon atoms such as hydroxynonyl Ether (meth) acrylic acid alkyl amides (meth) methylamide acrylic acid, (meth) ethylamide acrylic acid, (meth) acrylic acid propyl amide,
(Meth) acrylic acid butylamide, (meth) acrylic acid hexylamide, (meth) acrylic acid octylamide,
Alkylamides having 1 to 18 carbon atoms, such as (meth) acrylic acid decylamide, (meth) acrylic acid laurylamide, (meth) acrylic acid stearylamide, etc. Styrene-acrylic resins are the acrylic monomers and styrene-based resins. An aqueous binder resin obtained by copolymerizing monomers.

Here, as the styrene-based monomer, one or more selected from unsaturated aromatic compounds having 8 to 9 carbon atoms such as styrene, α-methylstyrene, vinyltoluene and the like can be used. it can.

Further, the styrene-maleic acid resin is
An aqueous binder resin obtained by copolymerizing the styrene monomer and the maleic monomer.

Here, as the maleic acid monomer,
One or more selected from maleic anhydride, maleic acid, and a maleic acid derivative can be used.

The maleic acid derivatives are an alkyl half ester of maleic acid, a hydroxyalkyl half ester, an alkyl polyalkylene glycol half ester of maleic acid, and an alkyl half amide. It is a half ester compound with one monoalcohol or a diol component having 2 to 9 carbon atoms, or a half amide compound with an amine component having 1 to 18 carbon atoms.

Finally, the styrene-acryl-maleic acid resin is an aqueous binder resin obtained by copolymerizing the styrene monomer, the acrylic monomer and the maleic monomer.

In the above aqueous binder resin, the content of the carboxyl group required for aqueous conversion is determined by adjusting the acid value of the aqueous binder resin to 50 to 250, preferably 80 to 250.
It is an amount in the range of ~ 200. Here, if the acid value of the aqueous binder resin is less than 50, the solubility of the resin in water decreases, causing separation or sedimentation.
When it is larger than 0, the water resistance is reduced, and a favorable result cannot be obtained.

The aqueous binder resin has a glass transition temperature in the range of -50 to 120 ° C., preferably -40.
-40 ° C. When the glass transition temperature of the aqueous binder resin is lower than this range, the obtained coating agent,
The releasability from the hot roll at the time of press working is reduced, and if it is increased, creases and the like are generated, which is not preferable.

Further, the molecular weight (weight average molecular weight, the same applies hereinafter) of the aqueous binder resin is from 5,000 to
100,000, especially 10,000-30,00
A range of 0 is preferred.

Regarding the method for producing the aqueous binder resin according to the present invention, first, a mono- or polyalkylene glycol having a boiling point of 60 to 200 ° C. or its ether or ester solvent, an acetate ester solvent under an inert gas such as nitrogen or the like. A water-miscible solvent such as a solvent, an aromatic hydrocarbon-based solvent, a water-immiscible solvent such as a ketone-based solvent, and a monomer mixture of each of the above components are added. A reaction initiator such as oxide and azobisisobutyronitrile is added, and the mixture is added at 60 to 170 ° C. for 1 to 10 hours, preferably 4 to 8 hours.
After copolymerization for a period of time, the organic solvent can be distilled off to produce a solid copolymer.

Further, in using the aqueous binder resin, the solid copolymer can be added to water to which a base has been added, and used as an aqueous binder resin varnish.

As the base used for aqueous conversion, an inorganic base such as aqueous ammonia or an alkali metal hydroxide, or an organic base such as an organic amine can be used. Sodium hydroxide, potassium hydroxide and the like can be used as oxides, and monoethanolamine, diethanolamine, triethanolamine, morpholine and the like can be used as organic amines.

In the coating agent obtained using the above-mentioned inorganic extender pigment and the aqueous binder resin varnish, the content ratio thereof is such that the aqueous binder resin is 5 to 30 parts by weight based on 70 to 95 parts by weight of the inorganic extender pigment. (However, the sum of the inorganic extender and the aqueous binder resin is 100 parts by weight). Here, when the content ratio of the pigment is more than this range, it becomes difficult to produce the coating agent specified in the present invention,
High gloss cannot be obtained. On the other hand, when the content ratio of the pigment is low, the setting property of the offset ink is low.

In the coating composition according to the present invention, another binder resin can be used in combination with the purpose of improving the adhesiveness to paper and the rub resistance, etc., within the range not deteriorating the effects of the present invention. . Here, as the other binder resin, a resin used in an ordinary coating agent, an aqueous ink, or the like can be used.

Specifically, an aqueous resin such as polyvinyl alcohol or aqueous cellulose, an alkyl ester or alkyl amide compound of an unsaturated carboxylic acid such as acrylic acid, or a fatty acid vinyl ester type compound such as vinyl acetate is emulsion-polymerized. Aqueous resin emulsion obtained, aqueous SBR resin emulsion, and the like can be used.

In the case where the glass transition temperature of the aqueous binder resin specified in the present invention exceeds 40 ° C., when prevention of creases is more strongly required, other binder resins having a glass transition temperature of 40 ° C. or lower are required. Is preferably used together as a solid content of about 1/2.

Further, depending on the purpose, various additives such as a water-miscible solvent, an antifoaming agent, a release agent, and a coloring agent can be added and mixed. Examples of the water-miscible solvent include lower alcohols, polyhydric alcohols, and alkyl ethers or alkyl esters thereof.

Next, a method for producing a coating agent according to the present invention will be described.

The coating agent according to the present invention can be produced by first stirring and mixing the inorganic extender pigment and the aqueous binder resin varnish with a stirrer, and then performing a dispersion treatment with a bead mill or a ball mill. .

The bead mill referred to in the present invention is a cylindrical metal container (vessel) provided with a rotating shaft provided with a disk-shaped stirring blade (disk) or a rod-shaped stirring member.
In the meantime, the average particle size called media is 0.5-5m
m, usually filled with Ottawa sand, natural mineral beads, hard glass beads, metal beads, etc. of about 1 to 3 mm. When the rotating shaft rotates, the stirring blade or the stirring member stirs the media. Has become.
The dispersion treatment is performed by retaining the mixture of the pigment and the aqueous binder resin varnish therein.

The bead mill includes a continuous type and a batch type. For example, as a continuous type, a vertical sand grinder, a Glen mill, a horizontal type super mill, a dyno mill, etc. Both an attritor and an agitation mill can be used.

Regarding the dispersion processing conditions of the bead mill and the ball mill, the rotation speed of the mill, the type and the filling amount of the media, etc. are appropriately adjusted depending on the solid content, the processing amount, the flow characteristics, etc. of the mixture of the pigment and the aqueous binder resin varnish. be able to.

Among the above dispersers, it is preferable to use a continuous bead mill because a large amount of coating agent can be produced in a short time.

Next, a method for obtaining the coated paper of the present invention using the above coating agent will be described.

First, as the base paper to be coated with the coating agent according to the present invention, general high-quality paper or neutral paper-made base paper is used.

The coating composition according to the present invention is applied directly to base paper, or applied to a base material coated with another coating composition.

The coating can be carried out during or after papermaking. Examples of the coating machine include a roll coater, a doctor blade coater, a knife edge coater, a curtain coater, a gravure coater and a bar coater. Can also be used. Further, it can be coated on one or both sides of the base paper, and the coating amount is usually in the range of 10 to 40 g / m ² (dry weight) in one or more coatings.

The base paper on which the coating agent has been applied is subjected to hot pressing. As the hot press processing, after the coating agent was applied to the base paper, the coating agent was solidified by an acid treatment after the direct or indirect casting method in which the coating agent was hot pressed while the coating agent was kept wet. Either a gel casting method in which hot pressing is performed later, or a raster processing method in which pressing is performed after the coating agent is completely dried, can be adopted.
This gives a glossy finish to a coated paper.

The hot pressing is usually performed at 90 to 1
Using a mirror-finished metal roll heated to 60 ° C., at a line speed of 10 to 150 m / min,
It is performed under the condition of a linear pressure of 0 to 150 kg / cm.
When the heating temperature of the metal roll is lower than the above range, the press efficiency is reduced and the surface smoothness is poor. On the other hand, when the heating temperature is higher than the above range, the press suitability is reduced and the coating agent layer is deteriorated due to bumping of water. Invite.

The coated paper manufactured by the above manufacturing method is a coated paper which can be printed by a normal offset printing method and gives a printed material having good printability and very high gloss.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” represent “parts by weight” and “% by weight”.

Aqueous Binder Resin Varnish Production Example 1 Ethyl acetate (600 parts) was charged into a four-necked flask equipped with a stirrer, a cooling tube, and a nitrogen gas inlet tube, heated to 75 to 78 ° C., and nitrogen gas was introduced. While methacrylic acid 50
Parts, methyl methacrylate 120 parts, styrene 130 parts,
A mixture of 100 parts of 2-ethylhexyl acrylate and 4 parts of di-tert-butyl peroxide as a reaction initiator was added dropwise over 2 hours. Further, after random copolymerization for 2 hours while maintaining the same temperature, the solvent was evaporated under reduced pressure to obtain an aqueous binder resin having an acid value of 81 and Tg (glass transition temperature, the same applies hereinafter) of 30 ° C.

After crushing 400 parts of the aqueous binder resin, the mixture was stirred and mixed with 600 parts of water in which an equivalent amount of ammonia was dissolved, and dissolved by heating at 80 ° C. to obtain an aqueous binder resin varnish No. 1 having a solid content of 40%. I got 1.

Production example 2 of aqueous binder resin varnish Production example of aqueous binder resin varnish except that the monomer composition was changed to 50 parts of methacrylic acid, 50 parts of methyl methacrylate, 50 parts of styrene, and 250 parts of 2-ethylhexyl acrylate. Aqueous binder resin varnish No. 1 having a solid content of 40% under the same conditions as in No. 1. I got 2.

(Aqueous Binder Resin Acid Value 81, Tg-40 ° C.) Aqueous Binder Resin Varnish Production Example 3 The monomer composition was changed to 50 parts of methacrylic acid, 140 parts of methyl methacrylate, 140 parts of styrene, and 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as in the aqueous binder resin varnish production example 1 except that the amount was changed to 70 parts. I got 3.

(Aqueous Binder Resin Acid Value 81, Tg 49 ° C.) Aqueous Binder Resin Varnish Production Example 4 The monomer composition was changed to 50 parts of methacrylic acid, 80 parts of methyl methacrylate, 80 parts of styrene, and 110 parts of 2-hydroxyethyl methacrylate. Parts, 2-ethylhexyl acrylate 80
Production example 1 of aqueous binder resin varnish except for changing to part
Under the same conditions as those of the aqueous binder resin varnish No. 40% solids, I got 4.

(Acid Value of Aqueous Binder Resin 81, Tg 32 ° C.) Aqueous Binder Resin Varnish Production Example 5 The monomer composition was changed to 50 parts of methacrylic acid, 100 parts of methyl methacrylate, 110 parts of styrene, and 40 parts of acrylamide.
Parts, aqueous binder resin varnish No. having a solid content of 40% under the same conditions as in Production Example 1 of aqueous binder resin varnish except that the amount was changed to 100 parts of 2-ethylhexyl acrylate. 5
I got

(Aqueous Binder Resin Acid Value 81, Tg 32 ° C.) Aqueous Binder Resin Varnish Production Example 6 The monomer composition was changed to 120 parts of methacrylic acid, 80 parts of methyl methacrylate, 100 parts of styrene, and 100 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish No. I got 6.

(Aqueous Binder Resin Acid Value 197, Tg 32 ° C.) Aqueous Binder Resin Varnish Production Example 7 Except that the monomer composition was changed to 120 parts of methacrylic acid, 160 parts of methyl methacrylate, and 120 parts of 2-ethylhexyl acrylate Is an aqueous binder resin varnish No. having a solid content of 40% under the same conditions as those of the aqueous binder resin varnish production example 1. I got 7.

(Aqueous Binder Resin Acid Value 197, Tg 27 ° C.) Aqueous Binder Resin Varnish Production Example 8 An aqueous binder resin varnish was prepared except that the monomer composition was changed to 300 parts of monoethoxyethoxyethyl maleate and 100 parts of styrene. Under the same conditions as in Production Example 1, a solid content of 40%
Aqueous binder resin varnish No. I got 8.

(Acid Value of Aqueous Binder Resin 120, Tg 30 ° C.) Aqueous Binder Resin Varnish Production Example 9 The monomer composition was changed to 80 parts of methacrylic acid and 160 parts of styrene.
Parts, 80 parts of butyl maleate, and 80 parts of 2-ethylhexyl acrylate under the same conditions as in Production Example 1 of aqueous binder resin varnish, and an aqueous binder resin varnish No. having a solid content of 40% was used. I got 9.

(Acid Value of Aqueous Binder Resin 196, Tg 39 ° C.) Aqueous Binder Resin Varnish Production Example 10 The monomer composition was changed to 180 parts of methacrylic acid, 50 parts of methyl methacrylate, 60 parts of styrene, and 110 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. I got 10.

(Aqueous Binder Resin Acid Value 294, Tg 29 ° C.) Aqueous Binder Resin Varnish Production Example 11 The monomer composition was changed to 50 parts of methacrylic acid, 20 parts of methyl methacrylate, 40 parts of styrene, and 290 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish No. I got 11.

(Acid Value of Aqueous Binder Resin 81, Tg-54 ° C.) Coating Agent Production Examples 1 to 19 After mixing the inorganic extender pigment and the aqueous binder resin varnish having the composition shown in Table 1 with a stirrer, 100-5
After adjusting the viscosity with water so as to be 00 poise, the residence time in the vessel was set to 0.7 using a horizontal bead mill.
Dispersion processing was performed by adjusting the ejection amount so as to fall within the range of ~ 1.4 minutes. Here, the dispersion condition is that the particle size is 1.7.
Glass beads of about mm were filled to 80% of the volume of the vessel, and the peripheral speed of the disk was 78 m / min.

The inorganic pigment / water-based binder resin varnish dispersion obtained by the above-mentioned dispersion treatment is further treated with S
A predetermined amount of the BR resin aqueous emulsion and water were added, and the mixture was stirred and mixed. 1-19 were obtained.

Coating Agent Production Example 20 An inorganic extender pigment and sodium polyacrylate as a pigment dispersant were stirred and mixed with a propeller-type stirrer in accordance with the composition shown in Table 1, and then an aqueous SBR resin emulsion and water were added. No. 20 were produced.

Production Example 21 of Coating Agent According to the composition shown in Table 1, an inorganic extender pigment, sodium polyacrylate as a pigment dispersant, and a starch derivative were stirred and mixed with a propeller-type stirrer. Dispersion treatment was performed under the same conditions as in the production of Nos. 1 to 19. Further, an aqueous emulsion of SBR resin and water were added, and 21 were produced.

Production Example 22 of Coating Agent 3 was stirred with a propeller-type stirrer. 22 coatings were obtained.

The above coating agent No. Examples of the materials Nos. 1 to 22 include, as calcium carbonate, white luster T-DD (average particle size 0.14 μm, manufactured by Shiraishi Calcium Co., Ltd.), PC
(Average particle size 0.46 μm, Shiraishi Calcium Co., Ltd.
P-50 (average particle diameter 1.15 μm, manufactured by Toyo Fine Chemical Co., Ltd.) as kaolin clay as BRI
LLIANT-15 (manufactured by Ishihara Sangyo Co., Ltd.) was converted into an aqueous emulsion of SBR resin using JSR-0624 (Tg-1).
4 ° C., solid content 48%, manufactured by Nippon Synthetic Rubber Co., Ltd.).

Coating agent No. After storing Nos. 1 to 22 for 7 days at an ambient temperature of 40 ° C, the change in fluidity was evaluated. Sample No. 21 did not have fluidity even after vigorous shaking, and was not subjected to subsequent evaluation tests.

Examples 1 to 14 and Comparative Examples 1 to 7 1 to 20, 22 were coated on a cast base paper with a 0.15 mm diameter bar and dried at room temperature. Then, using a mirror drum heated to 108 ° C., a line speed of 60 m / min and a line speed of 60 m / min. Gloss finishing was performed under the conditions of a pressure of 100 kg / cm, and coated papers of Examples 1 to 14 and Comparative Examples 1 to 7 were obtained.

The coated papers were evaluated for gloss, printing ink setting, pick strength, water resistance, press suitability and crease evaluation. The results are shown in Table 2.

The evaluation method is as follows.

(1) Gloss A 60-degree gloss value was measured with a gloss meter, and the gloss value was evaluated based on the value. Evaluation criteria A: Measured value of 80 or more B: Measured value of 60 or more and less than 80 C: Measured value of less than 60 (2) Printing ink setting property Offset ink was printed on a 1cc / 200cm2 plate, and a set test was performed with an offset ink set tester (manufactured by Toyo Seiki Co., Ltd.)
The settability of the ink was evaluated from the set time.

Evaluation criteria A: Set time of less than 1 minute B: Set time of 1 minute or more and less than 3 minutes C: Set time of 3 minutes or more (3) Pick strength Suitability of offset ink for fogla printing Using a testing machine,
Printing at a printing pressure of 60 KPa and a printing speed of 120 m / min,
The transfer of the coating layer to the plate cylinder was visually evaluated.

Evaluation criteria A: No transfer to the plate cylinder B: Partial transfer to the plate cylinder C: Complete transfer to the plate cylinder (4) Water resistance To the coated surface of the coated paper (4 cm × 5 cm) , 0.1 ml of water was dropped, and the coated surface (dry surface) of the same coated paper was put thereon, a load of 1 kg / cm ² was applied thereto, and left at 25 ° C. for 24 hours. After peeling off, the water resistance was evaluated from the state at that time.

Evaluation criteria A: Coated surface peels off without resistance B: Pigment slightly migrates to the mating surface upon peeling C: Coated surfaces adhere to each other (5) Press aptitude When performing gloss finish, The transfer of the working layer to the hot roll was evaluated by visual judgment.

Evaluation Criteria A: No transfer to hot roll B: Partial transfer to hot roll C: Transfer completely to hot roll (6) Crackability Coated paper with coated side inside After bending, a cellophane tape was stuck to the coated surface and peeled off. The creasing property was evaluated from the state of the coating agent layer and the amount of peeling.

A: The coating agent layer does not crack and does not peel off at all. B: The coating agent layer partially cracks, but the fold portion does not peel. C: The entire coating agent layer cracks. Only the upper layer of the fold part peels off D: Cracks occur in the entire coating agent layer, and all the layers of the fold part peel off

[0090]

[Table 1]

[0091]

[Table 2]

[0092]

As described above in detail with reference to the examples, the coating agent specified in the present invention is applied to base paper and pressed by a hot roll to set an excellent printing ink. And coated paper having higher glossiness.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Kojima 1-23-37 Edobori, Nishi-ku, Osaka-shi Inside Saka Tinex Co., Ltd. (56) References JP-A-3-241095 (JP, A) (58) Investigated Field (Int.Cl. ⁷ , DB name) D21H 11/00-27/42

Claims (4)

(57) [Claims] 1. The following conditions (a), (b) and (c)
Is applied to the base paper in an amount of 10 to 40 g / m ^2.
A method for producing coated paper, wherein the coated paper is coated with (dry weight) and then pressed using a hot roll heated to 90 to 160 ° C. (A) As a solid content of the coating agent, the average primary particle diameter is 0.0
4 to 1.0 μm of calcium carbonate and other inorganic extender pigments, the weight ratio of both being 30/70 to 100
/ 0, an inorganic extender pigment, an acid value of 50 to 250, and a glass transition temperature of -50 to 120 ° C, from an acrylic resin, a styrene-acrylic resin, a styrene-maleic acid resin, and a styrene-acryl-maleic acid resin. It contains at least one aqueous binder resin selected from the group consisting of: (B) The weight ratio of the inorganic extender and the aqueous binder resin is 70/30 to 95/5. (C) The inorganic extender is dispersed by a bead mill or a ball mill. 2. The method for producing coated paper according to claim 1, wherein the average primary particle diameter of the calcium carbonate is 0.04 to 0.50 μm. 3. The method for producing coated paper according to claim 1, wherein the glass transition temperature of the aqueous binder resin is −40 to 40 ° C. 4. Coated paper obtained by the method for producing coated paper according to claim 1, 2 or 3.