JP3137751B2 - Method for producing matte lightweight coated paper for gravure printing - 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 matte lightweight coated paper for gravure printing, which has a low misdot ratio,
The present invention relates to a method for producing a matte light-weight coated paper for gravure printing having excellent dot reproducibility and excellent print strikethrough.

[0002]

2. Description of the Related Art Gravure printing is excellent in color tone reproducibility of printed matter because the area and depth of a halftone dot of a plate can be changed, and is used for high quality printed matter. Recently, the trend of printing paper has shifted from glossy to matte. This seems to be because users have come to prefer calm objects with gentle eyes, instead of those with noticeable surface glare and difficult to read characters. Also,
There is an increasing demand for better print finish in picture parts such as photographs. Under such circumstances, matte coated paper for gravure printing has recently been used to obtain legibility of the text and sharpness of the pattern.

[0003] The gravure printing, first giving the ink to the entire plate, scraped off the ink of non-image areas with soil compactors to the next,
In this method, the ink accumulated in the recesses is transferred to paper under pressure. For this reason, the smoothness of the paper surface is necessary in order for the ink in the concave portion to smoothly and uniformly transfer to the paper. The smoothness referred to here is smoothness in a state of being compressed under printing pressure, and is also called so-called dynamic smoothness, and requires cushioning. In addition, oil absorption is required to improve the transferability of the ink.

A number of patent applications have been filed with respect to a matte coated paper for gravure printing by specifying a pigment formulation and the like (Japanese Patent Application Laid-Open Nos. 59-199897 and 1-1).
18695) were all medium-grade base papers using mechanical pulp to provide cushioning properties, and were matte coated papers without a high-grade feel. On the other hand, in the base paper made of bleached chemical pulp alone that gives a high-quality feel, there is no matte coated paper for gravure printing that is likely to cause misdots because it cannot provide cushioning properties and is sufficiently satisfactory. When the basis weight is low, the opacity is low, and there is a problem of print strikethrough.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a matte light weight for gravure printing which is excellent in print strike-through, has high whiteness, and has a high quality, even if the product has a low white paper gloss and a low misdot ratio and is lighter in weight. To obtain an excellent quality matte lightweight coated paper for gravure printing by applying a specific coating solution twice to the base paper of chemical pulp alone, drying and smoothing to obtain coated paper Was found.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a frosted lightweight coated paper for gravure printing, which has a long diameter of 4 as a pigment component of an undercoating layer in order to suppress the gravure suitability and the print-through property.
50% by weight or more of columnar light calcium carbonate having a particle diameter of 0 μm or less and a minor diameter of 0.5 μm or less, and heavy calcium carbonate having a particle diameter of 0.5 to 3.0 μm as a pigment component of the overcoat layer.
0% or more, using bleached chemical pulp alone
Low-gloss coated paper and low-gloss white paper with low glossiness and low mis-dot ratio due to smoothing treatment, excellent in print strike-through even with lightweight paper, high whiteness, high-grade matte lightweight coated paper for gravure printing Was found. The ratio of the columnar light calcium carbonate used in the undercoat layer used in the present invention is preferably 50% by weight or more, and more preferably 60% by weight or more based on all the pigments. If the ratio of the columnar light calcium carbonate to all the pigment components is less than 50% by weight, the opacity is reduced and the problem of print strikethrough occurs. Further, even with other light calcium carbonates having different shapes, the opacity is reduced, and the problem of print strikethrough occurs.
However, if the undercoating layer is applied only once, there is no problem such as print strikethrough, but the pigment is oriented on the surface of the coating layer due to the shape of the columnar calcium carbonate, so that the glossiness of white paper increases, and the matte coating is performed. Not suitable for papermaking. Therefore, heavy calcium carbonate having a particle size of 0.5 to 3.0 μm, which is hard to give out white paper gloss,
By providing a top coat layer containing 0% or more and applying two coats and smoothing, the matte weight for gravure printing is low for the first time because of low glossiness of white paper and misdot ratio and excellent print-through. Coated paper can be obtained. The basis weight of the lightweight coated paper of the present invention generally refers to a paper having a weight of about 70 g / m ² or less.

[0007] Regarding the base paper used for coating,
By using the base paper of bleached chemical pulp alone, it is possible to produce a matte coated paper with high whiteness and high quality. Examples of pigments other than the pigments used in the present invention include kaolin, clay, satin white, titanium oxide,
Examples include aluminum hydroxide, zinc oxide, barium sulfate, calcium sulfate, silica, activated clay, and silicon earth.

The adhesive used in the present invention includes various adhesives such as styrene / butadiene, styrene / acrylic, vinyl acetate / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylic, and vinyl acetate / butyl acrylate. copolymers and polyvinyl alcohol, maleic acid-styrene copolymer anhydride, isobutylene Ten anhydrous maleic acid copolymer,
Synthetic adhesives such as acrylic acid / methyl methacrylate copolymers; oxidized starch, etherified starch, esterified starch, enzyme-modified starch and cold water-soluble starch obtained by flash-drying them, casein, soy protein, etc. Commonly known adhesives such as natural adhesives can be used. Also,
If necessary, various auxiliaries to be added to ordinary coating pigments, such as a dispersant, a thickener, a water retention agent, a defoaming agent, a waterproofing agent, and a coloring agent, can be used as appropriate.

[0009] Methods for coating liquid according to the present invention is applied to the base paper is not specifically limited, an air knife coater over,
Conventional various coating apparatuses such as a roll coater, various blade coaters, and short dwell coaters are used. The coating amount of the undercoating layer is 1 to 8 on one side, which is a normal coating amount range.
g / ^{m 2,} preferably there is no problem if the 4~7g / ^{m 2.} Even in the range of the coating layer of the top coating layer, 4 to 15 g /
In m ² approximately, the basis weight of the toe barrel is to 70 g / ^{m 2} or less degree of the product. Thus, the coated paper which has been coated with the coating liquid and dried can be finished through a device such as a super calender, a soft calender, etc., but the glossiness of white paper (JIS P 814)
2) is 40% or less.

[0010]

EXAMPLES The effects of the present invention will be described below with reference to examples, but the present invention is not limited thereto. In the examples, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively. Further, various test methods in the examples are as follows. (1) Misdot ratio: A test piece was printed using a dot gravure as a picture using a gravure printing tester (manufactured by Kumagaya Riki Kogyo Co., Ltd.) of the Ministry of Finance. The ratio of the number of generated misdots to the total number of halftone dots is indicated by% as the misdot ratio. The smaller the value, the better. (2) Blank gloss: measured at an angle of 75 degrees according to JISP8142.

(3) Whiteness: Measured with a Hunter whiteness tester according to JISP8123. (4) Opacity: Measured with a Hunter whiteness tester according to JISP8123. (5) Print strikethrough: 0.35 mL to 0.45 m of black ink
RI printing was performed with L, and the back surface was visually evaluated. The evaluation results were displayed as follows. ◎: no strikethrough, ○: normal, ×: strikethrough,

Example 1 Undercoat Coating Layer Columnar light calcium carbonate having a major axis of 1.5 to 3.0 μm and a minor axis of 0.1 to 0.3 μm (trade name: TP-, manufactured by Okutama Industry Co., Ltd.)
123) 50 parts of heavy calcium carbonate having a particle size of 1.4 μm (manufactured by Sankyo Flour Milling Co., Ltd., trade name: Escalon # 2000) 30
Section and kaolin (product name: Beta Gloss, manufactured by ECC) 2
0 parts were dispersed in water using 0.4 part of sodium polyacrylate as a dispersant so as to have a solid content of 72%, and 8 parts of an alkali-sensitive SB latex and 2.5 parts of an enzyme-modified starch were further used as adhesives. CMC was added as an agent, and auxiliaries such as a waterproofing agent and a release agent were added and blended to obtain a coating liquid having a concentration of 62%. The pulp component is exposed to this with a blade coater and the kraft pulp is 100% by weight and 40 g / m ² of base paper (A).
And dried so that the coating amount was 14 g / m ^{2 on} both sides.

Top coat layer Heavy calcium carbonate having a particle size of 1.4 μm (Sankyo Flour Milling Co., Ltd.)
Using 80 parts of Escalon # 2000 (trade name, manufactured by ECC Corporation) and 20 parts of kaolin (beta gloss, manufactured by ECC) as a dispersant, using 0.4 part of sodium polyacrylate as a dispersant to obtain a solid content of 72 parts.
% Of an alkali-sensitive SB latex and 2.5 parts of an enzyme-modified starch as an adhesive.
In addition, CMC was added as a water retention agent, and a water-proofing agent and an auxiliary agent such as a release agent were added and blended to obtain a coating solution having a concentration of 62%. This coating solution is further coated on the coated paper obtained above with a blade coater so that the coating amount is 10 g / m ² on both sides, dried, and further subjected to a super calender treatment to obtain a matte light weight for gravure printing. A coated paper was obtained. Table 1 shows the quality evaluation results of the obtained coated paper.

COMPARATIVE EXAMPLE 1 A base paper was prepared by using 30 parts of columnar light calcium carbonate and 50 parts of heavy calcium carbonate and 20 parts of kaolin in the undercoating layer, and blending 75 parts of bleached kraft pulp with 25 parts of mechanical pulp. A matte lightweight coated paper for gravure printing was obtained in the same manner as in Example 1 except that (B) was used.

Comparative Example 2 The undercoat coating solution of Example 1 was exposed to kraft pulp 4
The base paper (A) having a coating weight of 0 g / m ² was coated once and dried at a coating amount of 24 g / m ^{2 on} both sides, dried, and further subjected to a super calender treatment to obtain a matte lightweight coated paper for gravure printing. .

[0016]

[Table 1]

Base paper used A: bleached kraft pulp alone B: bleached kraft pulp 75 parts, mechanical pulp 25 parts

[0018]

As is apparent from Table 1, Example 1 has a low blank gloss level, a high opacity and a high whiteness, and has an excellent level of the misdot ratio. On the other hand, Comparative Example 1 is inferior in opacity and has a problem of print strike-through, and further inferior in whiteness and does not have a high-grade feeling. In Comparative Example 2, the glossiness of white paper was high, and the coated paper was not matte-coated.

Continuation of front page (72) Inventor Sachi Sakamoto 2-8-1 Iida-cho, Iwakuni-shi, Yamaguchi Prefecture Sanyo Kokusaku Pulp Co., Ltd. Production Technology Laboratory (56) References JP-A-5-214699 (JP, A) 60-119294 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D21H 11/00-27/42

Claims (1)

(57) [Claims] 1. A method for producing a matte light-weight coated paper for gravure printing in which a coating liquid is applied twice to a base paper, the major diameter of which is 4.0 μm.
Thereafter, the undercoat coating liquid containing 50% by weight or more of columnar light calcium carbonate having a minor axis of 0.5 μm or less is exposed to a chemical pulp 10
0% by weight, and a particle size of 0.5-3.
A matte light weight coating for gravure printing, characterized by applying a top coating liquid containing 50% or more of 0 μm heavy calcium carbonate, drying and smoothing the white paper gloss to 40% or less. Manufacturing method of paper.