WO2018155649A1

WO2018155649A1 - Coated paper for cold set offset printing

Info

Publication number: WO2018155649A1
Application number: PCT/JP2018/006792
Authority: WO
Inventors: 川島　正典; 遼外岡; 周平稲田; 詩織柿木
Original assignee: 日本製紙株式会社
Priority date: 2017-02-24
Filing date: 2018-02-23
Publication date: 2018-08-30
Also published as: CN110366621A; JP2018141260A

Abstract

Provided is a coated paper for cold set offset printing, said coated paper comprising a pigment coating layer on one or both sides of a base paper. The coated paper has a basis weight of 60–200 g/m². The pigment coating layer includes calcium carbonate having an average particle size of no more than 0.95 μm. There is at least 5 g/m² of the pigment coating layer per side. The coated paper demonstrates excellent printing characteristics and does not easily wrinkle.

Description

Cold-set offset coated paper

The present invention relates to a cold-set type offset printing coated paper.

Newspaper paper is usually printed on newspaper rotary presses that do not have a drying device using penetrating dry (cold set) newspaper dedicated ink. Conventionally, uncoated paper and fine coated paper (Patent Document 1: Japanese Patent Laid-Open No. 2003-286686) having no pigment coating layer are known as newspaper paper. However, the printed matter obtained by printing on these papers with a newspaper rotary press is inferior in drying property and low in print gloss compared with the printed matter obtained by printing on coated paper with a commercial printing machine equipped with an ink drying device. It was inferior.

On the other hand, in a rotary printing press, when the remaining amount of paper decreases, paper splicing is performed instantaneously and automatically without stopping the rotary press in order to avoid a reduction in work efficiency. In a rotary press operating at high speed, there is a problem that wrinkles are generated on newsprint because of the large impact at the time of paper splicing. For this reason, a method for preventing the occurrence of wrinkles (Patent Document 2: Japanese Patent Application Laid-Open No. 2011-168401) and a method for reducing the number of times of paper joining itself (Patent Document 3: Japanese Patent No. 5886664) have been proposed.

JP 2003-286686 A JP 2011-168401 A Japanese Patent No. 5886664

In order to improve the printing gloss, the inventors tried to print on a pigment-coated paper having a relatively high gloss, such as a coated paper for printing, using a newspaper rotary press. However, there are problems such as poor ink penetration and stains on the printed matter. Furthermore, the inventors have found that the problem of wrinkles during printing cannot be solved simply by using a printing coated paper provided with a pigment coating layer. In view of the above, an object of the present invention is to provide a cold-set type offset printing coated paper that exhibits excellent printing characteristics and is less likely to wrinkle.

The inventors have found that a cold-set type offset printing coated paper having a specific basis weight and having a specific pigment coating layer solves the above problems. That is, the said subject is solved by the following this invention.
(1) Cold-set type offset printing coated paper having a pigment coating layer on one side or both sides of a base paper,
The basis weight is 60 to 200 g / m ² ,
The pigment coating layer contains calcium carbonate having an average particle size of 0.95 μm or less,
The coating amount of the pigment coating layer is 5 g / m ² or more per side,
Cold set offset coated paper.
(2) The cold-set type offset printing coated paper according to (1), comprising 50 parts by weight or more of calcium carbonate in 100 parts by weight of the pigment in the pigment coating layer.
(3) The cold-set type offset printing coated paper according to (1) or (2), comprising 40 parts by weight or more of kaolin or clay in 100 parts by weight of the pigment in the pigment coating layer.
(4) The cold-set offset printing coated paper according to any one of (1) to (3), wherein the base paper contains 80 parts by weight or more of chemical pulp with respect to 100 parts by weight of pulp.
(5) The cold-set type offset printing coated paper according to any one of (1) to (4), wherein the density is 0.8 to 1.3 g / cm ³ .
(6) The cold-set offset printing coated paper according to any one of (1) to (5), wherein the coating amount of the pigment coating layer is 5 to 30 g / m ² per side.
(7) The cold-set type offset printing coated paper according to any one of (2) to (6), wherein the calcium carbonate has an average particle size of 0.8 μm or less.
(8) The cold-set type offset printing coated paper according to any one of (3) to (7), wherein the kaolin or clay has an average particle size of 6.0 μm or less.
(9) The cold-set offset printing coated paper according to any one of (1) to (8), wherein the glossiness of white paper is 25 to 80%.
(10) The cold-set type offset printing coated paper according to any one of (1) to (9), wherein the ISO whiteness is 80% or more.
(11) The cold-set offset printing coated paper according to any one of (1) to (10), wherein the ISO bending stiffness in the MD direction is 150 μN · m ² / m or more.
(12) The coated paper for cold set offset printing according to any one of (1) to (11), wherein the difference in printing gloss is 5 points or more.
(13) A winding paper obtained by winding the cold-set type offset printing coated paper according to any one of (1) to (12).
(14) A printing method wherein printing is performed on the cold-set offset printing coated paper according to any one of (1) to (12) or the winding paper according to (13) using a rotary press.

According to the present invention, it is possible to provide a cold-set type offset printing coated paper which exhibits excellent printing characteristics and hardly causes wrinkles.

Hereinafter, the present invention will be described in detail. In the present invention, “X to Y” includes X and Y which are end values.

Cold set type offset printing coated paper is coated paper that can be offset printed with penetrating dry ink, and can be used for newspaper rotary printing with newspaper rotary press and penetrating drying type special ink for newspaper. Includes craft paper. Newspaper printing webs are coated paper for newspaper rotary printing in the form of rolls. The cold-set type offset printing coated paper used in the present invention includes a pigment coating layer on one side or both sides of a base paper.

(1) Pigment coating layer The pigment coating layer is a layer containing a white pigment as a main component. Commonly used pigments such as calcium carbonate, kaolin, clay, calcined kaolin, amorphous silica, zinc oxide, aluminum oxide, satin white, aluminum silicate, magnesium silicate, magnesium carbonate, titanium oxide, plastic pigment, etc. Is mentioned. Of these, calcium carbonate having an average particle size of 0.95 μm or less is preferable, and calcium carbonate having an average particle size of 0.9 μm or less is more preferable from the viewpoint of improving ink penetration and reducing wrinkles. 0.8 μm or less is more preferable, and 0.7 μm or less is more preferable. The lower limit is not particularly limited, but the average particle size is about 0.1 μm or more, preferably 0.5 μm or more. By using the fine calcium carbonate within the above range, a coated paper having high gloss can be obtained even when a flat pigment such as kaolin or clay is not used or only a small amount thereof is used. The calcium carbonate to be used may be only calcium carbonate having the average particle diameter, or may be mixed with calcium carbonate having a particle diameter larger than the upper limit of the average particle diameter. The average particle size can be measured with a laser diffraction particle size distribution analyzer such as Mastersizer manufactured by Malvern. Examples of calcium carbonate include heavy calcium carbonate and light calcium carbonate. Moreover, you may use the light calcium carbonate (causticized light calcium carbonate) described in patent 5274077 etc. as light calcium carbonate. The calcium carbonate content is preferably 50 parts by weight or more and more preferably 70 parts by weight or more in 100 parts by weight of the white pigment. Although the upper limit of calcium carbonate content is not limited, it is preferably 100 parts by weight or less, and more preferably 90 parts by weight or less. The 50% volume average particle diameter (D50) measured by the laser diffraction particle size distribution analyzer or the like can be used as the average particle diameter of the pigment. By containing 50 parts by weight or more of calcium carbonate, a high white cold set type coated paper for offset printing can be obtained.

In order to improve the drying property, it is preferable to use kaolin or clay for the pigment coating layer. Kaolin or clay is preferably at least 40 parts by weight per 100 parts by weight of the white pigment. When kaolin and clay are used in combination, the total amount of both is preferably 40 parts by weight or more in 100 parts by weight of the white pigment. When kaolin or clay is used, it is possible to obtain a coated paper for high gloss cold set offset printing. The average particle size of kaolin or clay is preferably 6.0 μm or less, more preferably 5.5 μm or less. The lower limit of the average particle diameter is not limited, but is preferably 1.0 μm or more, and more preferably 2.0 μm or more. The 50% volume average particle diameter (D50) measured by a laser diffraction particle size distribution analyzer or the like can be used as the average particle diameter of kaolin or clay.

The pigment coating layer contains an adhesive. Examples of the adhesive include oxidized starch, positive starch, urea phosphated starch, etherified starch such as hydroxyethyl etherified starch, various starches such as dextrin, proteins such as casein, soy protein, synthetic protein, polyvinyl Alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl-based polymers such as ethylene-vinyl acetate copolymer Polymer latex etc. are mentioned. These can be used alone or in combination of two or more. By using a mixture of starch-based adhesive and latex-based adhesive, there is an excellent balance between the coating suitability of the pigment coating solution and the printing suitability such as surface strength, and also suppresses wrinkling during printing. This is preferable because it is possible. The total amount of adhesive in the pigment coating layer is preferably 1 to 15 parts by weight, more preferably 2 to 14 parts by weight, and even more preferably 3 to 13 parts by weight with respect to 100 parts by weight of the pigment.

The pigment coating layer may contain various auxiliaries such as a dispersant, a thickener, an antifoaming agent, a colorant, an antistatic agent and an antiseptic used in the general paper manufacturing field.

The pigment coating layer can be provided by coating the coating liquid on one side or both sides of the base paper by a known method. The solid content concentration in the coating solution is preferably about 30 to 70% by weight from the viewpoint of coating suitability. The pigment coating layer may be one layer, two layers, or three or more layers. When a clear coating layer is provided, the pigment coating layer is one layer, and when no clear coating layer is provided, pigment coating is performed. It is preferable to provide two construction layers. By providing at least the pigment coating layer of the present invention, or by providing two coating layers of the pigment coating layer and the clear coating layer of the present invention, the base paper of the binder component in the outermost coating layer It is possible to suppress penetration into the resin and to obtain sufficient coating layer strength and rigidity. When two or more pigment coating layers are provided, it is preferable that at least the outermost pigment coating layer farthest from the base paper is the pigment coating layer of the present invention. The coating amount of the pigment coating layer is 5 g / m ² or more in total per side, and preferably 10 g / m ² or more. The upper limit is preferably 30 g / m ² or less, and preferably 25 g / m ² or less. When the coating amount is lower than 5 g / m ² , the drying property of the ink is inferior, and furthermore, the base paper cannot be sufficiently covered, so that the high printing gloss and the clear printed image of the present invention may not be obtained. There is. When it is higher than 30 g / m ² , the stiffness of the paper becomes low, and the generation of wrinkles may not be suppressed.

(2) Base Paper The pulp raw material of the base paper used in the present invention is not particularly limited. Mechanical pulp such as ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), deinked pulp (DIP), Chemical pulps such as softwood kraft pulp (NKP) and softwood kraft pulp (LKP) can be used. As the deinking (waste paper) pulp, it is possible to use selected waste paper such as high quality paper, medium quality paper, lower grade paper, newspaper, flyers, magazines, etc. or unselected waste paper in which these are mixed. The cold-set type offset printing coated paper of the present invention preferably contains 80 parts by weight or more, more preferably 90 parts by weight or more of chemical pulp in 100 parts by weight of pulp. By containing 80 parts by weight of chemical pulp, it is possible to obtain a cold-set type offset printing coated paper having high whiteness, excellent printing strength, and less wrinkling.

A known filler can be added to the base paper. Fillers include heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate, barium sulfate, aluminum hydroxide, calcium hydroxide, Inorganic filler such as amorphous silica produced by neutralization of magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide, sodium silicate with mineral acid, urea-formalin resin, melamine resin, polystyrene resin, phenol Examples include organic fillers such as resins. These may be used alone or in combination. Of these, calcium carbonate and light calcium carbonate-silica composite, which are typical fillers for neutral papermaking and alkaline papermaking and which can provide high opacity, are preferable.

As the internal additive, a bulking agent, a dry paper strength improver, a wet paper strength improver, a freeness improver, a dye, a neutral sizing agent, and the like may be used as necessary. Examples of the dry paper strength improver include polyacrylamide and cationized starch, and examples of the wet paper strength improver include polyamidoamine epichlorohydrin. These chemicals are added within a range that does not affect the formation and operability. Examples of neutral sizing agents include alkyl ketene dimers, alkenyl succinic anhydrides, and neutral rosin sizing agents. These internally added chemicals can be used together with pulp and filler as needed to make paper.

The base paper is manufactured by a known paper making method. For example, it can be carried out using a long net paper machine, a gap former type paper machine, a hybrid former type paper machine, an on-top former type paper machine, a round net paper machine, etc., but is not limited thereto. The cold-set type offset printing coated paper of the present invention may be produced by an on-machine method in which the paper making process and the pigment coating process are continuous, and the off-machine is applied in the pigment coating process after the paper making process. You may manufacture by a method. The paper making and coating speed is preferably 400 to 2000 m / min.

(3) Other treatment The cold set type offset printing coated paper of the present invention may further have a clear coating layer mainly composed of an adhesive on one side or both sides of the base paper. The clear coating layer is preferably adjacent to the base paper layer, but may be provided on the outermost layer farthest from the base paper. The adhesive used for the clear coating layer is as described above. When a clear coating layer is provided adjacent to the base paper, it is possible to suppress penetration of the pigment coating liquid into the base paper, which is preferable because the base paper coverage of the pigment coating layer is improved. Starch is preferred. Moreover, the strength of the base paper is improved by the penetration of the clear coating liquid into the base paper. From the above, the coating amount of the clear coating layer on both sides, preferably 0.5 g / ^{m 2} or more 5.0 g / ^{m 2} or less, 1.0 g / ^m, more preferably ² or more 4.5 g / ^{m 2} or less, More preferably, it is 2.0 g / m ² or more and 4.0 g / m ² or less.

The cold-set type offset printing coated paper of the present invention may be subjected to a surface treatment. Examples of the surface treatment include a soft calendar, a super calendar, a gloss calendar, a thermal calendar, and a shoe calendar.

(4) Properties of cold-set type offset printing coated paper 1) Basis weight Generally, the pigment coated paper grade is about 80 to 150 g / m ² and the pigment coated paper grade is about A2 grade. The pigment coated paper having a basis weight of about 60 to 80 g / m ² is classified into A3 grade, and the paper to be used is selected according to the application. The basis weight of the cold-set type offset printing coated paper of the present invention is 60 to 200 g / m ² . If the basis weight is too high, the winding length is short, and the frequency of paper change on the rotary press increases, so the risk of paper breakage increases. In addition, since the paper is highly stiff, it is difficult to print on the web, and the difference in thickness from that of normal newsprint paper increases, leading to an increased risk of mechanical problems. On the other hand, if the basis weight is too low, the generation of wrinkles at the time of paper joining cannot be suppressed. From the above, the lower limit of the basis weight is preferably 60 g / m ² or more, and more preferably 70 g / m ² or more. Upper limit of the basis weight is preferably from 180 g / ^{m 2} or less, more preferably 170 g / ^{m 2} or less. The basis weight of the cold-set type offset printing coated paper of the present invention is more preferably 80 g / m ² or more and 150 g / m ² or less of A2 grade. The coated paper for A2 grade cold set offset printing of the present invention is less likely to cause wrinkling during printing, and can provide excellent print gloss and image sharpness. The basis weight is measured according to JIS P8124.

2) Winding Diameter The winding paper obtained by winding the cold-set type offset printing coated paper of the present invention is useful as a newspaper printing paper, and the winding diameter is preferably 850 to 1200 mm. The roll diameter is the diameter of the web (roll) and is calculated by using the following formula:
D = (4 tL / π + d ² ) ^1/2 × 1000
D: winding diameter (mm), t: paper thickness (m), L: winding length (m), d: diameter of core rod (m)
When the winding diameter is less than the lower limit value, the winding length is shortened, the number of times of paper splicing during printing is increased, and work efficiency and the like can be reduced. On the other hand, if the winding diameter exceeds the upper limit value, the transport efficiency may be reduced, and the printing press may not be able to cope. In this respect, the lower limit value of the winding diameter is preferably 890 mm or more, and more preferably 900 or more. The upper limit of the winding diameter is preferably 1150 mm or less, and more preferably 1100 mm or less.

3) Density The density of the cold-set type offset printing coated paper of the present invention is preferably 0.8 to 1.3 g / cm ³ . If the density exceeds the upper limit, the paper strain may be lowered. Further, since it is necessary to reduce the coating amount in order to make it less than the lower limit value, as a result, the drying property and printing gloss of the ink are lowered, and the effect of the present invention may not be obtained. In this respect, the lower limit value of the density is preferably 0.8 g / cm ³ or more, and more preferably 0.9 g / cm ³ or more. The upper limit of the density is preferably 1.3 g / cm ³ or less, 1.2 g / cm ³ or less is more preferable.

4) White Paper Glossiness The white paper glossiness of the cold-set type offset printing coated paper of the present invention is preferably 25 to 80%. When a matte texture is required for the printed matter, it is preferably 25 to 50%, and when a glossy texture is required, it is preferably 50 to 80%. Matte-style cold-set offset coated paper does not undergo calendering, or if it is done, it is a minor process, so the density of cold-set offset coated paper is small and wrinkles are not generated. Can be suppressed, which is preferable. Further, a matte-like cold set type offset printing coated paper having a glossiness of 25 to 50% is excellent in drying property at the time of printing. The blank paper glossiness is measured according to JIS P8142.

5) ISO whiteness The ISO whiteness of the cold-set type offset printing coated paper of the present invention is preferably 80% or more, and more preferably 82% or more. When the ISO whiteness is within this range, a clear image can be obtained when newspaper rotary printing is performed. ISO whiteness is measured according to JIS P8148.

6) Bending Stiffness coldset type coated paper for offset printing of the ISO bending stiffness in the MD direction of the present invention is preferably at 150μNm ² / m or more, more preferably 200μNm ² / m or more. Furthermore, ISO flexural stiffness in the CD direction is preferably at 100μNm ² / m or more, more preferably 120μNm ² / m or more. When the ISO bending stiffness is within this range, the generation of wrinkles during paper splicing can be suppressed. In addition, when the newspaper is widened, the newspaper does not bend by its own weight when the newspaper is spread, and the newspaper is easy to read and turn. ISO bending stiffness is measured according to ISO 2493.

7) Glossiness of printing The printing glossiness (indigo: C, red: M) of the coated paper for offset printing of the present invention when printed with newspaper printing (cold set) ink is 10-80. % Is preferred. When printed on matte-like cold-set type offset printing coated paper, 15 to 55% is preferable, and when printed on glossy-type cold-set type offset printing coated paper, 55 to 85% is preferable. When the printing glossiness is within this range, the printing characteristics are good. The print glossiness is measured according to JIS P81428. Further, the print glossiness difference defined as a value obtained by subtracting the blank paper glossiness from the print glossiness is preferably 5 points or more, more preferably 8 points or more. The cold-set type offset printing coated paper of the present invention has a high printing gloss even when a penetrating ink for newspaper printing is used, so that images such as photographs are clear.

[Example 1]
After preparing a paper containing 100% by weight of LBKP as a base paper and 13% by weight of light calcium carbonate as a filler, a 1% by weight of cationized starch was applied and a solid content of 3 g / m ² was applied. An amount of clear coating was provided, and high-quality paper having a density of 0.73 g / cm ³ and a basis weight of 51.4 g / m ² was prepared.

Heavy calcium carbonate as a pigment (manufactured by Pfematech Co., Ltd., trade name: FMT97, proportion of particles having a particle diameter of 2 μm or less by sedimentation method: 97%, D50 = 0.88 μm) 55 parts by weight (solid content) and second grade 45 parts by weight (solid content) of clay (made by IMERYS, trade name: KCS, D50 = 4.9 μm), and styrene-butadiene copolymer latex (made by A & L, trade name: PB9501, average) as an adhesive 4 parts by weight of particle size 80 nm, glass transition temperature -12 ° C), 6 parts by weight of oxidized starch (trade name: SK200, manufactured by Nippon Corn Starch Co., Ltd.), and water added to a solid content concentration of 66% by weight A pigment coating solution was obtained.

On the base paper, the pigment coating solution was coated on both sides with a blade coater so that the dry coating amount per side was 15.0 g / m ^2, and then dried to obtain a coated paper for printing. From the coated paper for printing, a roll paper having a roll diameter of 970 mm was produced by a conventional method. The coated paper for printing was evaluated as described later.

[Example 2]
A coated paper for printing was obtained in the same manner as in Example 1 except that high-quality paper having a basis weight of 74.7 g / m ² was prepared as the base paper. From the coated paper for printing, a wound paper having a winding diameter of 920 mm was produced by a conventional method. Evaluation was performed in the same manner as in Example 1.

[Example 3]
A coated paper for printing was obtained in the same manner as in Example 1 except that high-quality paper having a basis weight of 97.9 g / m ² was prepared as the base paper. From the coated paper for printing, a web having a winding diameter of 960 mm was produced by a conventional method. Evaluation was performed in the same manner as in Example 1.

[Example 4]
Bulky chemical as an organic compound having an effect of inhibiting fiber-to-fiber bonding of pulp, using 80% by weight of LBKP and 20% by weight of NBKP as the base paper and containing 20% by weight of light calcium carbonate as the internal additive per base paper weight. A high-quality base paper having a basis weight of 40.5 g / m ² containing 0.5% by weight of the base paper weight (KB 110, manufactured by Kao Corporation) was prepared.

As a pigment, 77 parts by weight of light calcium carbonate (average particle size: 0.95 μm) and 23 parts by weight of fine kaolin (manufactured by JM Huber, Japan Gloss) are used. Part by weight was added and dispersed with a serie mixer to prepare a pigment slurry having a solid content of 70% by weight. To the pigment slurry thus obtained, 8.5 parts by weight of a styrene-butadiene latex and 4.8 parts by weight of hydroxyethyl etherified starch are added, and water is further added to form a coating solution having a solid content concentration of 64% by weight. Obtained.

After applying oxidized starch with a gate roll coater to the base paper so that the coating amount on both sides is 1.5 g / m ² in solid content, calendering is performed at 1 nip, 15 kN / m, and metal roll surface temperature of 50 ° C. went. Then, apply the above-mentioned pigment coating solution on both sides with a blade coater at a coating speed of 700 m / min so that the coating amount on one side is 9 g / m ² in solids, and then dry and apply matte coated paper. Obtained. From the coated paper, a web having a winding diameter of 990 mm was produced by a conventional method. Evaluation was performed in the same manner as in Example 1.

[Example 5]
Wrapping paper was produced and evaluated in the same manner as in Example 1 except that the secondary clay was changed to FMT100 manufactured by Pfematech Co., Ltd. (ratio of particles of 2 μm or less, 100%, D50 = 0.66 μm).

[Example 6]
100 parts by weight of heavy calcium carbonate (Fmatec FMT90 (90% ratio of particles of 2 μm or less, D50 = 1.15 μm)), 7 parts by weight of styrene butadiene latex, 3 parts by weight of oxidized starch, Was added to obtain an undercoating liquid having a solid content of 66% by weight. The base paper used in Example 2 was not provided with a clear coating layer, and on the base paper, the under coating liquid was coated on both sides at a coating amount of 5 g / m ² per side and then dried. Further, using the pigment coating solution prepared in Example 5 as a top coating solution, double-side coating was performed at a coating amount of 10 g / m ² per side, and drying was performed to produce a web.

[Example 7]
An under coating solution was prepared by changing FMT90 of the under coating solution used in Example 6 to causticized light calcium carbonate for coating (D50 = 1.38 μm) manufactured by Nippon Paper Industries Co., Ltd. The top coating solution FMT97 used in Example 5 was coated with causticized light calcium carbonate (D50 = 1.02 μm) manufactured by Nippon Paper Industries Co., Ltd., and FMT100 was coated with causticized light calcium carbonate (D50 manufactured by Nippon Paper Industries Co., Ltd.). = 0.64 μm) to prepare a top coating solution. Using these, the base paper used in Example 3 was not provided with a clear coating layer, and a coating layer was provided on the base paper in the same manner as in Example 6 to produce a roll paper and evaluated.

[Comparative Example 1]
Pulp slurry prepared by mixing newspaper deinked pulp, TMP, and NKP at a weight ratio of 80: 15: 5 as a base paper, and light calcium carbonate (average particle size of 4.1 μm) as a filler is 4.0 wt. % Was added to prepare a paper stock. Using this stock, newspaper base paper was made at a speed of 1000 m / min with a gap former type twin wire paper machine, and then the coating amount of hydroxyethylated starch was felt with an on-machine gate roll coater. Coating was performed so that both the surface and the wire surface were 0.2 g / m ^2, and newsprint paper having a basis weight of about 42 g / m ² (41.7 g / m ² ) was obtained. From the newsprint, a web having a winding diameter of 1093 mm was produced by a conventional method. Evaluation was performed in the same manner as in Example 1.

[Comparative Example 2]
As a base paper, light calcium carbonate (average particle size 4.3 μm, whiteness 95%) is used as a filler in a pulp slurry in which LBKP, newspaper bleach DIP, cedar TMP, and NKP are mixed at a weight ratio of 35: 5: 30: 30. Newspaper paper was made using a gap former type paper machine at a speed of 1000 m / min and a basis weight of 58 g / m ² using a gap former type paper machine. Next, hydroxyethylated starch was applied with an on-machine gate roll coater so that the coating amount was 0.5 g / m ^{2 on} both the felt surface and the wire surface. Processing was carried out to obtain 0.67 g / cm ³ to obtain newsprint. From the newsprint, a web having a winding diameter of 1050 mm was produced by a conventional method. Evaluation was performed in the same manner as in Example 1.

[Comparative Example 3]
Using LBKP 90% by weight and NBKP 10% by weight as the base paper, adjusting the paper stock so that the target paper ash content is 19% with light calcium carbonate as the internal filler, basis weight 60.5g at a papermaking speed of 650 m / min A high-quality base paper / m ² was prepared.

A cationized starch was applied to the base paper with a gate roll coater so that the coating amount on both sides was 3.5 g / m ² in terms of solid content to obtain a high quality paper. A roll paper having a roll diameter of 970 mm was produced from the fine paper by a conventional method. Evaluation was performed in the same manner as in Example 1.

The results are shown in Table 1. It is clear that the cold-set type offset printing coated paper of the present invention exhibits excellent printing characteristics and is less likely to wrinkle.

Details of the evaluation method will be described below.
(1) White paper glossiness Measured based on JIS-P8142.

(2) Print gloss (print gloss difference)
Using rotary offset printing press B2T-600 (4 colors) manufactured by TOSHIBA CORPORATION, newspaper rotary ink (VANTEAN ECHO manufactured by Toyo Ink Co., Ltd.), printing speed of 900 rpm and solid ink ink density of 0.90 indigo. , And printed in the order of red (CM) so as to be red 0.90. The glossiness of the indigo red (CM) solid printed part of the obtained printed matter was measured based on JIS P-8142.
A value obtained by subtracting the blank paper glossiness from the print glossiness was defined as a print glossiness difference (Δ gloss). If the difference in print glossiness is 5 points or more, the difference in gloss between the printed portion and the blank paper portion is sufficiently obtained, and a printed matter with good appearance can be obtained.
Print gloss difference = Print gloss (%)-Blank paper gloss (%)

(3) Basis weight It measured based on the "basis weight measuring method" as described in JIS-P8124.

(4) Paper Thickness and Density Measured in accordance with “Paper and Paperboard—Test Method for Thickness and Density” described in JIS-P8118.

(5) Opacity Measured according to JIS-P8149: 2000.

(6) ISO bending stiffness The bending stiffness in the MD direction (papermaking direction) and the CD direction was measured in accordance with ISO2493.

(7) Smoothness Beck smoothness Measured based on JISP8119.

(8) Whiteness ISO whiteness measurement method: Measured with a light source including ultraviolet light using a color difference meter CMS-35SPX manufactured by Murakami Color Co., Ltd. according to JIS P8148.

(9) Tensile strength and elongation According to JIS P8113, the paper piece was pulled under certain conditions, and the strength and elongation until breaking were measured. Elongation was expressed as a percentage of the initial test length.

(10) Stains on the paper Offset printing (4 colors) is performed using cold set ink on an offset rotary press (B2T-600 manufactured by Toshiba Corporation), and the ink generated on the paper surface of the printed matter is insufficiently dried. The degree of occurrence of ink stains due to the fact was judged by visual evaluation. ◎: No paper stains ○: Slightly dirty but usable △: Slightly dirty cannot be used ×: Many stains cannot be used

(11) Roll dirt By offset printing (four colors) using cold set ink on the offset rotary press, and in the roll where the paper surface comes into contact after passing through the printing unit, the ink is transferred due to insufficient drying of the paper surface. The degree of occurrence of dirt was determined by visual evaluation.
◎: Roll is not soiled ○: Slightly soiled but printable △: Slightly soiled and hinders printing

(12) Wrinkles Offset printing (4 colors) was performed using cold set ink on the offset rotary press, and the degree of wrinkles occurring in the printed material after passing through the printed folding portion was determined.
5: Wrinkles are not generated at all. 4: Wrinkles are slightly generated but can be used without any problems. 3: Wrinkles are generated slightly, but they can be used. 2: Wrinkles are slightly generated. Can not

(13) Print quality Offset printing (four colors) was performed using cold set ink on the offset rotary press, and the degree of print quality such as density and gloss of the printed matter was determined in five stages by sensory evaluation.
5: Extremely clear 4: Clear 3: Slightly clear 2: Inferior in sharpness but not problematic for practical use 1: Inferior in sharpness and not usable

(14) Tear strength Measured according to JIS P8112: 2008.

Claims

Cold set type offset printing coated paper having a pigment coating layer on one or both sides of a base paper,
The basis weight is 60 to 200 g / m 2 ,
The pigment coating layer contains calcium carbonate having an average particle size of 0.95 μm or less,
The coating amount of the pigment coating layer is 5 g / m 2 or more per side,
Cold set offset coated paper.
The cold-set offset printing coated paper according to claim 1, comprising 50 parts by weight or more of calcium carbonate in 100 parts by weight of the pigment in the pigment coating layer.
The cold-set type offset printing coated paper according to claim 1 or 2, comprising 40 parts by weight or more of kaolin or clay in 100 parts by weight of the pigment in the pigment coating layer.
The cold-set offset printing coated paper according to any one of claims 1 to 3, wherein the base paper contains 80 parts by weight or more of chemical pulp with respect to 100 parts by weight of pulp.
The cold-set offset printing coated paper according to any one of claims 1 to 4, wherein the density is 0.8 to 1.3 g / cm 3 .
The cold-set offset printing coated paper according to any one of claims 1 to 5, wherein the coating amount of the pigment coating layer is 5 to 30 g / m 2 per side.
The cold-set offset printing coated paper according to any one of claims 2 to 6, wherein the calcium carbonate has an average particle size of 0.8 µm or less.
The cold set type offset printing coated paper according to any one of claims 3 to 7, wherein the average particle diameter of the kaolin or clay is 6.0 µm or less.
The cold set type offset printing coated paper according to any one of claims 1 to 8, wherein the glossiness of the blank paper is 25 to 80%.
The cold-set type offset printing coated paper according to any one of claims 1 to 9, wherein the ISO whiteness is 80% or more.
The cold-set offset printing coated paper according to any one of claims 1 to 10, wherein the ISO bending stiffness in the MD direction is 150 µN · m 2 / m or more.
The cold-set offset printing coated paper according to any one of claims 1 to 11, wherein the printing gloss difference is 5 points or more.
A winding paper obtained by winding the cold-set type offset printing coated paper according to any one of claims 1 to 12.
A printing method, wherein printing is performed on the cold-set type offset printing coated paper according to any one of claims 1 to 12 or the winding paper according to claim 13 using a rotary press.