JP2002161494A - High-gloss paper for gravure printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gravure printing paper of excellent sophisticated feeling. SOLUTION: This gravure printing paper is obtained by coating the obverse and/or reverse face(s) of a basal paper with a coating liquid containing a hollow organic pigment 0.2-0.5 μm in particle size followed by drying and then subjecting the coated surface(s) to supercalendering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gravure printing paper used for gravure printing, and more particularly to a high gloss paper for gravure printing having high blank gloss and high printing gloss.

[0002]

2. Description of the Related Art Hitherto, gravure printing, which is a type of intaglio printing, is well known as a printing means for obtaining fine and high-quality printed materials such as posters, calendars, high-grade photo books, and the like. In recent years, higher-quality printed matter has been demanded, and gravure printing technology has been improved in definition. Along with this, there is an increasing demand for gravure printing paper with low drydown and high quality.

In general, it is known that it is effective to increase the gloss of a printing paper in order to enhance the quality of a printed matter. Conventionally, the glossiness of a blank sheet and the printing gloss of the printing paper have been improved. Various proposals have been made on techniques for this.

[0004] For example, there is a cast coating method in which a coating liquid containing a pigment and an adhesive as a main component is coated on the surface of a base paper, and the coating layer is pressed against a heated metallic mirror drum and dried. A method of applying a coating composition containing a thermosoftening organic pigment, drying the coating composition, and pressing the coating composition in a dry state to a surface of a mirror-finished roll at a temperature higher than the softening point of the thermosoftening organic pigment (Japanese Patent Publication No.
148898) and the like.

[0005] The printing paper obtained by these prior arts has a high glossiness and high printing gloss and high quality.

[0006]

However, the printing papers obtained by the above-mentioned prior art are all developed mainly for letterpress printing. In intaglio printing, high smoothness is required because the ink in the cells of the plate needs to be sufficiently transferred to the paper. In particular, in intaglio printing, high-definition printing such as gravure printing requires a small drydown.

In the former cast coating method, voids are formed in the coating layer because the coating layer in a wet state is directly pressed against a heating drum and dried, and the resulting printing paper has low smoothness. Dry down, in which ink penetrates into the voids and the ink density and print gloss gradually decrease, is also large.

In the printing paper obtained by the method disclosed in Japanese Patent Publication No. 1-148898, the portion existing on the surface of the coating layer or a portion closer thereto by high-temperature calendaring is very dense due to deformation of the organic pigment. However, dry-down is not prevented because there are voids inside. Moreover, in this method, high-temperature calendering is performed, so that the coating surface is uneven and the smoothness is reduced due to the influence of the texture of the base paper.

As described above, the glossy printing paper obtained by the conventional technique is not suitable for gravure printing in terms of smoothness and dry down.

[0010] Therefore, the main object of the present invention is to provide a high smoothness without occurrence of dry-down, which is suitable for gravure printing, and a high glossiness and high glossiness of white paper and printing gloss.
It is to provide a high gloss paper for gravure printing.

[0011]

According to the first aspect of the present invention, there is provided gravure printing paper used for gravure printing, wherein at least one of the front and back surfaces of the base paper is provided.
A coating liquid containing a hollow organic pigment having a particle size of 0.2 μm to 0.5 μm and a delaminated clay having an aspect ratio of 30 to 60 is applied and dried, and then the coated surface is subjected to a super calendar treatment. It is a high gloss paper for gravure printing characterized by being made.

(Effect) Since the organic pigment used in the present invention is thermoplastic, it can be super-calendered to
Gloss is developed in the coating layer, resulting in high gloss printing paper. Also,
Since the hollow organic pigment is used, the surface is easily deformed by the super calendar process to form a coated surface having high smoothness. In addition, since the hollow pigment is easily deformed, it is not affected by the formation of the base paper even if it is subjected to the calendar treatment. Furthermore, since the hollow organic pigment having a small particle size is used, voids are reduced and the structure of the surface of the coating layer and the inside of the coating layer are more dense, and the dry down is improved. In addition, since the coated layer contains a delaminated clay having an aspect ratio of 30 to 60, the glossiness is enhanced and the quality is higher.

[0013]

Embodiments of the present invention will be described below in detail. The present inventors have conducted intensive studies to produce high gloss paper having suitability as gravure printing paper, and as a result, the hollow organic pigment having a specific particle size and an aspect ratio of 30 to
A coating liquid containing 60 delaminated clay is coated on at least one of the front and back surfaces of the base paper, and after drying, the coated surface is subjected to a super calender treatment, so that dry down is small and printing gloss is high, The inventors have found that a high gloss paper for gravure printing having no gloss unevenness and excellent in gravure printing suitability can be obtained, and the present invention has been completed.

The hollow organic pigment used in the present invention has a particle size of 0.1.
It is 2 μm to 0.5 μm. If the particle size is less than 0.2 μm, the deformation does not proceed sufficiently by the super calendar treatment, so that the gloss development is poor and the smoothness does not increase. When it exceeds 0.5 μm, the stability of the aqueous dispersion is inferior, so that the viscosity of the coating liquid is increased, which causes disturbance of the coated surface and lowers the smoothness. It is necessary to use a hollow organic pigment because a solid organic pigment without voids is unlikely to be deformed by the super calendar process.

It is desirable that the hollow organic pigment has a glass transition temperature of 100 to 150 ° C. When the glass transition temperature is less than 100 ° C., when the coating liquid is applied and dried, the deformation and fusion of the pigment particles proceed, so that the bulkiness of the coating layer is reduced and the gloss development after the super calendar treatment is low. . Conversely, when a hollow pigment exceeding 150 ° C. is used, supercalendering at a high temperature is required, so that the base paper is discolored and the white glossiness is reduced.

The hollow organic pigment is preferably used in an amount of 5 to 20 parts by weight based on 100 parts by weight of all the pigment components contained in the coating liquid.

If the number of parts is less than 5, the deformability during the calendar processing is poor, and it is difficult to obtain a highly glossy coating layer. If the amount exceeds 20 parts by weight, the viscosity of the coating liquid increases, so that it becomes difficult to apply the coating liquid using a coating apparatus. In addition, an increase in the glossiness of blank paper tends to level off.

Furthermore, in the present invention, the coating liquid contains a laminate clay having an aspect ratio of 30 to 60. By blending such a delaminated clay, glossiness is enhanced and higher gloss is achieved. The delamination clay contains 10% of all pigment components contained in the coating solution.
When it is 0 parts by weight, it is preferably 15 to 25 parts by weight.

In the coating liquid according to the present invention, in addition to the hollow organic pigment and the delaminated clay, clay,
Known pigments such as calcium carbonate, satin white, titanium oxide, aluminum hydroxide, zinc oxide, barium sulfate, calcium sulfate, silica, activated clay, diatomaceous earth, and lakes may be contained.

The adhesive used in the coating liquid according to the present invention includes a styrene / butadiene-based adhesive and a styrene / butadiene-based adhesive.
Various copolymers such as acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, and synthesis of polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, etc. Examples include natural adhesives such as system adhesives, oxidized starch, esterified starch, enzyme-modified starch, cold-water-soluble starch obtained by flash-drying them, casein, soy protein, and the like. These adhesives are used in an amount of 5 to 25 parts by weight, more preferably about 6 to 15 parts by weight, per 100 parts by weight of the pigment. 5
When the amount is less than the weight part, the adhesiveness is low and a suitable coating layer is not formed. Conversely, if the amount is 25 parts by weight or more, the glossiness is poorly expressed.

The coating liquid according to the present invention may contain, if necessary, a dispersant, a thickener, a water retention agent, a defoaming agent, a waterproofing agent,
Various auxiliaries, such as a colorant, to be blended with a normal pigment for coated paper may be contained.

The coating of the coating liquid is performed on the base paper by a general coating apparatus such as a blade coater, an air knife coater, a roll coater, a brush coater, a curtain coater, a bar coater, a gravure coater, and a size press coater. It can be divided into multiple layers and applied on one or both sides.

The solid content of the coating solution is generally 40 to
70% by weight, but considering the operability of the coating apparatus,
A range of 5 to 65% by weight is preferred.

The base paper may be a general printing coated paper.
Basis weight used 30 to 400 g / m ^TwoPaper base
Alternatively, board-based base paper is used.
Is not particularly limited, acid papermaking, alkaline papermaking
Either one may be used.

The raw pulp for the base paper is not particularly limited. Chemical pulp such as known KP, PGW, SGP, RG
It can be mechanical pulp such as P, BCTMP, CTMP, etc., deinked pulp, waste paper pulp, or non-wood pulp derived from kenaf, bamboo, hemp, straw and the like. These pulp may be used alone or in combination of two or more. In particular, when the pulp containing the PGW in an amount of about 3 to 10% by weight is used as a raw material, the base paper becomes bulky, so that a high-grade glossy paper for gravure printing is obtained.

The high gloss paper for gravure printing of the present invention has a specular reflection smoothness particularly suitable for evaluating the smoothness of intaglio printing paper, which is 50% at a pressure of 20 kg / m ² .
%, Preferably 80% or more. In order to achieve such a range, the coating amount of the coating liquid and the roll pressure for the calendar treatment may be adjusted.

The amount of the coating solution applied to the base paper is about 10 to 50 g / m ² in terms of dry weight, but from 12 to 35 g / m ^{2 in} terms of white paper quality of the obtained coated paper. Most preferably, it is adjusted in a range. If it is less than 10 g / m ² , it is difficult to form a decoy coating layer in the coatability of the base paper, and it is difficult to develop smoothness due to the influence of the formation of the base paper. On the contrary 5
If it is 0 g / m ² or more, the resulting high gloss paper for gravure printing will not have any stiffness and will not have good printability. In addition, the cost increases.

The roll pressing condition of the super calendar is 100 to 400 kg / cm 2 in linear pressure, more preferably 150 to 400 kg / cm 2.
It is adjusted in the range of ~ 350 kg / cm. 100kg /
cm, a suitable smoothness cannot be obtained.
If it exceeds / cm, the paper thickness becomes thin, the opacity is reduced, and the sense of quality is reduced. In addition, fiber burning occurs and the glossiness of blank paper is reduced. The calender roll temperature is preferably in the range of 50 to 95 ° C. in order to stabilize the quality.
If it is lower than 50 ° C., a suitable coating layer cannot be formed. If it exceeds 95 degrees, fiber burning occurs and the glossiness of blank paper decreases.

On the other hand, in the high gloss paper for gravure printing of the present invention, it is desirable to adjust the regular reflection type smoothness at the coating amount measurement pressure of 20 kg / cm ² to 50 to 100%.

Here, the high gloss paper for gravure printing of the present invention is not necessarily limited to the use of only gravure printing, and can be used without problems in other known printing methods such as letterpress printing.

<Example> The present invention will be specifically described below with reference to examples. In the examples, parts and% indicate parts by weight and% by weight, respectively.

(Example 1) Hollow organic pigment having a particle size of 0.2 μm (trade name: LX407BP / manufactured by Zeon Corporation) 10
Parts, 65 parts of clay (trade name; Ultra White 90 / made by Engelhard), 25 parts of delaminated clay trade name; Hydraprint / Huber), and 1 part of calcium carbonate (trade name: FMT90 / Fimatec)
To 100 parts of 0 parts of the mixed pigment, 0.3 part of sodium polyacrylate (trade name: ARON T40M / manufactured by Toagosei Co., Ltd.) was added as a dispersant, and the mixture was dispersed in water using a Cowles disperser to obtain a solid content concentration. A 65% pigment dispersion was prepared. 0.3 part of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant, 1 part of phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as an adhesive,
8 parts of a styrene-butadiene copolymer latex (manufactured by Asahi Kasei Kogyo Co., Ltd.) was blended to obtain a coating solution having a solid content of 60%. This was coated with a blade coater at a coating amount of 13 g / m
Coating at ² and then dried to obtain a coated paper. One more
Using a 1 nip super calendar, metal roll temperature 70 ° C, speed 450m / min, linear pressure 300kg / cm
To obtain a high-gloss paper for gravure printing as Example 1.

Example 2 A hollow pigment having a particle size of 0.5 μm
5 parts of hollow organic pigment (trade name; MH5055 / manufactured by Zeon Corporation), 65 parts of clay (trade name: Ultra White 90 / manufactured by Engelhard Co.), 20 parts of delaminated clay trade name; , And calcium carbonate (trade name; FMT90 / manufactured by Pharmatec) 100 parts of the mixed pigment, and sodium polyacrylate (trade name: ARON T40M /
(Toa Gosei Co., Ltd.) was added and dispersed in water using a Cowles disperser to prepare a pigment dispersion having a solid content of 65%. 0.3 part of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant, 1 part of phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as an adhesive, styrene-butadiene copolymer latex ( 8 parts of Asahi Kasei Kogyo Co., Ltd.) to obtain a coating solution having a solid content of 60%. This was coated with a blade coater so that the coating amount was 13 g / m ² on one side, and dried to obtain a coated paper. Further, using a 11-nip super calendar, the metal roll temperature was 70 ° C., the speed was 450 m / min, and the linear pressure was 30.
By treating at 0 kg / cm 2, a high gloss paper for gravure printing as Example 2 was obtained.

Example 3 A hollow pigment having a particle size of 0.5 μm
15 parts of hollow organic pigment (trade name; MH5055 / Zeon Corporation), clay (trade name: Ultra White 90 /
Dispersant for 100 parts of a mixed pigment consisting of 60 parts of Engelhard Co., 20 parts of a delamination clay, trade name of Hydraprint / Huber, and 5 parts of calcium carbonate (trade name, FMT90 / Fimatec) 0.3 parts of sodium polyacrylate (trade name: ARON T40M / Toa Gosei) was added and dispersed in water using a Cowles disperser to prepare a pigment dispersion having a solid content of 65%. 0.3 part of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant, 1 part of phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as an adhesive, styrene-butadiene copolymer latex ( 8 parts of Asahi Kasei Kogyo Co., Ltd.) to obtain a coating solution having a solid content of 60%. This was coated with a blade coater so that the coating amount was 13 g / m ² on one side, and dried to obtain a coated paper. Further, using a 11-nip super calendar, the metal roll temperature was 70 ° C., the speed was 450 m / min, and the linear pressure was 30.
By treating at 0 kg / cm 2, a high gloss paper for gravure printing as Example 3 was obtained.

Comparative Example 1 A hollow pigment having a particle size of 0.55 μm
m, 10 parts of hollow organic pigment (trade name; MH5055 / Zeon Corporation), clay (trade name: Ultra White 90)
/ Engelhard Co., Ltd.) 65 parts, Delamination Clay trade name; Hydraprint / Huber Co., Ltd. 20 parts, and calcium carbonate (trade name: FMT90 / Fimatec Co., Ltd.) 5 parts Sodium acrylate (trade name; ARON T40M /
(Toa Gosei Co., Ltd.) was added and dispersed in water using a Cowles disperser to prepare a pigment dispersion having a solid content of 65%. 0.3 part of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant, 1 part of phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as an adhesive, styrene-butadiene copolymer latex ( 8 parts of Asahi Kasei Kogyo Co., Ltd.) to obtain a coating solution having a solid content of 60%. This was coated with a blade coater so that the coating amount was 13 g / m ² on one side, and dried to obtain a coated paper. Further, using a 11-nip super calendar, the metal roll temperature was 70 ° C., the speed was 450 m / min, and the linear pressure was 30.
A glossy paper as Comparative Example 1 was obtained by treatment with 0 kg / cm.

(Comparative Example 2) 5 parts of a hollow organic pigment having a particle size of 0.3 μm (trade name: Ropaike HP-1055 / Rohm & Haas Co.), clay (trade name: Ultra White 9)
0 / manufactured by Engelhard Co., Ltd.), 70 parts, delamination clay trade name;
And 100 parts of a mixed pigment of 10 parts of a mixed pigment of 10 parts of calcium carbonate (trade name; FMT90 / Fimatech Co., Ltd.) as a dispersant, sodium polyacrylate (trade name; ARON T40
M / Toa Gosei Co., Ltd.), and dispersed in water using a Cowles disperser to prepare a pigment dispersion having a solid content of 65%. 0.3 g of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant was added to the dispersion.
Parts, phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as adhesive, 1 part of styrene-butadiene copolymer latex (manufactured by Asahi Kasei Kogyo Co., Ltd.) and a solid content concentration of 60%
Was obtained. This was coated with a blade coater so that the coating amount was 13 g / m ² on one side, and dried to obtain a coated paper. Further, using a 11-nip super calendar, the metal roll temperature was 70 ° C., the speed was 450 m / min, and the linear pressure was 30.
By processing at 0 kg / cm 2, a glossy paper as Comparative Example 2 was obtained.

Comparative Example 3 10 parts of a solid organic pigment having a particle size of 0.3 μm (trade name: V1004 / manufactured by Zeon Corporation)
50 parts of clay (trade name; Ultra White 90 / manufactured by Engelhard), 30 parts of delaminated clay (trade name: Hydraprint / Huber), and 10 parts of calcium carbonate (trade name: FMT90 / Fimatec) Sodium polyacrylate as a dispersant for 100 parts of the mixed pigment (trade name: ARON T40M / Toa Gosei)
0.3 parts was added and dispersed in water using a Cowles disperser to prepare a pigment dispersion having a solid content of 65%. 0.3 part of calcium stearate (trade name: LB2700 / manufactured by Hyundai Chemical) as a lubricant, 1 part of phosphate esterified starch (manufactured by Nippon Shokuhin Kako) as an adhesive,
8 parts of a styrene-butadiene copolymer latex (manufactured by Asahi Kasei Kogyo Co., Ltd.) was blended to obtain a coating solution having a solid content of 60%. This was coated with a blade coater at a coating amount of 13 g / m
Coating at ² and then dried to obtain a coated paper. One more
Using a 1 nip super calendar, metal roll temperature 70 ° C, speed 450m / min, linear pressure 300kg / cm
To obtain a glossy paper as Comparative Example 3.

The evaluation results of Examples 1 to 3 and Comparative Examples 1 to 3 are as shown in the table.

[0039]

[Table 1]

(Quality Evaluation Method) The coating liquid viscosity, coating aptitude, blank gloss, blank gloss, specular reflection smoothness, and number of halftone dots in the table are values determined as follows. .

[Coating Suitability] The state of the blade at the time of coating was visually observed and judged. ：: No bleeding was observed, and high-speed coating was possible. X: The occurrence of bleeding was recognized, and it was difficult to apply at a high speed.

[Glossiness of Blank Paper] The glossiness of blank paper of the coated paper was visually observed and judged. ：: No uneven gloss is observed. X: Uneven gloss is observed.

[Blank gloss] Using a gloss meter manufactured by Murakami Color Research Laboratory, 75 ° according to JIS P 8142 method.
The gloss was measured. ：: 80% or more, ×: less than 80%. The numbers in parentheses in the table are measured values.

[Specular Reflection Smoothness] The specular reflection type smoothness at 20 kg / cm ² was measured using a microtopograph manufactured by Toyo Seiki. ：: 80% or more, ×: less than 80%. The numbers in parentheses in the table are measured values.

[Number of missing dots] Using a gravure printing aptitude tester manufactured by Kumagai Riki Kogyo Co., Ltd., Ministry of Finance, the number of missing dots in 175 lines, 10% halftone dots, 10 mm × 10 mm places, and 4747 pieces were measured. did. ：: Less than 30 netting defects, ×: 30 or more netting defects. The number in parentheses in the table indicates the number of net loss.

[0046]

As described in detail above, according to the present invention, it depends on the low smoothness or the dry-down, which has occurred in the high gloss paper obtained by the cast coating method or the blending of the solid organic pigment and the high-temperature calendaring. Thus, a high gloss paper for gravure printing having high glossiness suitable for gravure printing can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L055 AG11 AG12 AG27 AG48 AG56 AG63 AG76 AG89 AG94 AH02 AH37 AJ04 BE02 BE08 EA15 EA16 FA12 FA14 FA15 GA19

Claims (1)

[Claims] 1. A gravure printing paper used for gravure printing, wherein at least one of the front and back surfaces of the base paper has a particle size of 0.2 μm or more.
0.5 μm hollow organic pigment and aspect ratio of 30-60
A high gloss paper for gravure printing, characterized in that a coating liquid containing a delaminated clay is applied, dried, and then the coated surface is subjected to a super calendar treatment to make paper.