JPH08199495A - Cast-coated paper for aqueous gravure printing - Google Patents

Abstract

PURPOSE: To prepare cast-coated paper having excellent aqueous gravure printabllity, especially excellent ink drying properties and ink colorability as paper for gravure printing. CONSTITUTION: In cast-coated paper provided with a coated layer comprising pigment and a water-soluble and/or water-dispersible adhesive as main components, the cast-coated paper is provided with a coated layer which comprises a pigment having a ratio of 10-80 pts.wt. of the pigment having >=1.20ml/g relative sedimentation volume in 100 pts.wt. of the whole pigment as the pigment, at least 1-30 pts.wt. of an aqueous urethane resin based on 100 pts.wt. of the pigment as the water-soluble and/or water-dispersible adhesive and 1-25 pts.wt. of a water-soluble polymer based on 100 pts.wt. of the pigment and subjected to cast finishing to give the objective cast-coated paper for aqueous gravure printability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based gravure printing cast coat paper used in a gravure printing machine or the like using a water-based ink. More specifically, the present invention relates to an aqueous cast gravure printing cast coated paper having an excellent suitability for drying and coloring of the aqueous gravure ink.

[0002]

2. Description of the Related Art In recent years, as print images have become higher in quality and finer in definition, there has been an increasing demand for gravure printing for forming beautiful printed surfaces with good reproducibility of photographs and paintings. Conventionally, solvent-based inks have been used for gravure printing, but due to the recent increase in awareness of global environmental problems and work environment problems, so-called water-based inks that are solvent-free are being replaced. . However, in gravure printing using a water-based ink, the drying speed of the ink is remarkably slow as compared with the case where a solvent-based ink is used, and there are problems such as deterioration of the ink drying property of the printing surface.

In general, as a paper having a good ink drying property, a bulky pigment such as synthetic fine silica is used like an ink jet recording paper, and a coating layer having a porous coating layer structure is provided. Or by using a pigment having a large oil absorption amount, it is possible to impart high ink drying property (absorption property). However, on the other hand, it has a high ink drying property, but on the other hand, there is a problem that the ink color density is lowered due to the penetration of the ink dye into the coating layer.
Furthermore, the number of missing dots in gravure printing is large and the reproducibility of high-quality printed images is extremely low, which is a serious drawback.

The present invention utilizes cast coated paper as a water-based gravure printing paper as a measure against halftone dot loss, but the conventional cast coated paper has various drawbacks as a water-based gravure printing paper. There is. The production method and problems of the cast coated paper will be described below.

That is, as a method for producing cast coated paper (strong gloss paper for printing), there is a method in which a coating liquid composition containing a pigment and an adhesive as a main component is coated on a base paper and then cast-finished. As a cast finishing method, a wet casting method in which the coating layer in a wet state is pressed and dried while the coating layer is in a wet state, and the coating layer in a wet state is once dried or semi-dried. After being solidified, it is wet-plasticized with a rewetting liquid and pressed onto a mirror-finished heating drum to dry it by a rewet casting method, and the wet coating layer is put into a gel state and pressed onto a mirror-finished heating drum to dry it. There are three generally known methods, namely the chemical cast method.

All of these casting coat paper finishing methods are common in that the coating layer in the wet plasticized state is pressed onto a mirror-finished heating drum, dried, and released from the heating drum to copy the mirror surface. However, among those skilled in the art,
Each is recognized as an individual technology.

The cast coated paper thus obtained has an excellent surface smoothness as compared with a super calender-finished ordinary coated paper, and the number of missing dots is very high. An excellent gravure printing image with few dots and good dot reproducibility can be obtained.

[0008] However, in general, in cast coated paper, a film-forming substance such as an adhesive in the coating liquid composition forming the coating layer is high because the mirror surface drum surface of the cast coater is copied. Although it has gloss and excellent surface smoothness, the porosity of the coating layer is lost due to the presence of this film-forming substance, and the color density of the ink is high, but the ink dryness (absorption) during aqueous gravure printing is high. Properties), and problems such as ink swimming, show-through of ink, and decrease in printing speed occur, and it is extremely difficult to satisfy both ink drying property and ink color density at the same time. Is the current situation.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to achieve a high ink drying speed, a high ink color density, and no dot loss. An object of the present invention is to provide a cast coated paper for water-based gravure printing capable of printing a print image with good reproducibility at high speed.

[0010]

In order to obtain a cast coated paper which maintains the high smoothness inherent in cast coated paper and is excellent in aqueous gravure printing, the present inventors have developed a pigment and an adhesive. As a result of intensive studies on the combination of the above, by using a pigment having a specific specific settling volume as a pigment, an aqueous urethane resin as an adhesive, and a water-soluble polymer in combination, the drying property (absorption) of the aqueous gravure ink The inventors have found that a cast coated paper having excellent dot reproducibility and high ink color density can be obtained, and completed the present invention.

The use of an aqueous urethane resin in cast coated paper is disclosed in JP-A-3-167386 and JP-A-3-252.
473, JP-A-6-2299, JP-A-6-16699
No. 0, disclosed in Japanese Patent Laid-Open No. 6-248598.
However, when these are subjected to gravure printing, particularly aqueous gravure printing using an aqueous ink, they do not sufficiently exhibit ink absorbency, and there is a drawback that problems such as reduction in practical ink dryness cannot be solved. .

The present invention is a cast-coated paper provided with a paper base material and a coating layer composed of a pigment as a main component and an adhesive formed on at least one surface of the paper base material. The specific sedimentation volume in 100 parts by weight is 1.2
A pigment having a ratio of 0 ml / g or more of 10 to 80 parts by weight is used, and an aqueous urethane resin as an adhesive is 1 to 30 parts by weight per 100 parts by weight of the pigment, and a water-soluble polymer is 100 parts by weight of the pigment. The present invention relates to a cast coat paper for water-based gravure printing, characterized in that a coating layer containing an adhesive containing 1 to 25 parts by weight as a main adhesive component is provided and then cast-finished.

The cast coat for aqueous gravure printing of the present invention
The paper is a paper base (in the present specification, the base paper and the base paper having an undercoat layer containing a pigment or an adhesive as a main component on the base paper are collectively referred to as a paper base). After the coating liquid composition is applied to form a cast coating layer, it is produced by any of the known cast finishing methods such as a wet method, a rewet method and a gelling method, and particularly preferably a rewet method.

The cast coat for aqueous gravure printing of the present invention
It is essential that the paper has a pigment having a specific sedimentation volume of 1.20 ml / g or more. The pigment having a specific sedimentation volume of 1.20 ml / g or more in the present invention may be a pigment alone or a mixture.

This is because only the pigment having a specific sedimentation volume of less than 1.20 ml / g is not sufficient in the ink drying property (absorption property) during aqueous gravure printing. Further, the pigment having a specific sedimentation volume of 1.20 ml / g or more must be contained in an amount of 10 to 80 parts by weight based on 100 parts by weight of the total pigment.
If it is less than 0 part by weight, the ink absorbency is insufficient, and if it exceeds 80 parts by weight, the color density of the ink after printing is lowered, which is not preferable.

The specific sedimentation volume is 100% by weight of the pigment sample, 0.1 parts by weight of a dispersant (Toagosei; Aron T-40) is added, and the mixture is stirred and dispersed at 1500 rpm for 10 minutes to obtain a 10% pigment. The slurry was adjusted, and the pigment in this slurry was rotated at a rotation speed of 1800 rpm and a rotation radius of 170 mm for 6 times.
After centrifuging for 0 minutes, the volume A (m
l) is measured. Furthermore, this cake is dried, and the absolute dry weight B
The value obtained by measuring (g) and substituting these measured values into the following equation is referred to. Specific sedimentation volume = A / B (ml / g)

On the other hand, in the production of the cast coated paper for aqueous gravure printing of the present invention, an aqueous urethane resin is used among urethane resins. The urethane resin is a polymer having a urethane bond (-OOCHN-) in the molecule, and generally, a saturated polyol (H having two or more OH groups is used.
O-PE-OH) and polycyanate (OCN-Ar-N)
CO).

Particularly, as the polyol used for the aqueous urethane resin, diol or triol is generally used. Neopentylglycol as an example of diol
In addition to usual glycols such as 1,4-butanediol and 1,6-hexadiol, polyethylene glycol,
Polyether glycol represented by polypropylene glycol and polytetramethylene glycol, polyester polyol, acrylic polyol, epoxy polyol, polycarbonate carbonate and the like can be mentioned. In addition, diol having a tertiary amine such as N-methyldiethanolamine, diol having a carboxyl group such as dimethylolpropionic acid, and the like are also included.

The isocyanate used in the aqueous urethane resin is toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, hexamethylene diisocyanate. , Lysine diisocyanate, 4,4'-cyclohexyl isocyanate
, Methylcyclohexane-2,4 (2,6) -diisocyanate, 1,3-cyclohexane, isophorone diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate and the like. .

Further, it is made water-soluble with amines such as triethylamine and dimethylethanolamine, or a water-soluble amino resin such as methylated melamine resin,
An aqueous polyurethane resin obtained by crosslinking using a metal complex such as aziridine, an epoxy resin, or zinc can also be used. The form of the water-based urethane resin thus obtained is emulgion, colloidal disperser.
It may be in the form of an aqueous dispersion such as John or an aqueous solution.

The mixing ratio of the aqueous urethane resin in the present invention is 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the pigment. When the compounding ratio of the water-based urethane resin is less than 1 part by weight, a sufficient ink color density at the time of aqueous gravure printing on the coated surface cannot be obtained, and when it exceeds 30 parts by weight, the ink color density on the coated surface is exceeded. Is not improved to a certain level or more, that is, the color density of ink is saturated and the cost is increased, which is not preferable.

The cast coat for aqueous gravure printing of the present invention
The mechanism of the effect of improving the ink drying property and the ink color density in the paper is not particularly clear, but it is presumed as follows. That is, specific sedimentation volume 1.
Use of 20 ml / g or more of pigment makes the coating layer relatively porous. In addition, the urethane bond or carboxyl group in the water-based urethane resin accelerates the adsorption rate of the vehicle component in the water-based gravure ink, and the ink dye is fixed near the coating surface layer, so the ink density is increased and, as a result, the ink drying property is improved. It is estimated that the ink color density is improved.

Pigments having a specific sedimentation volume of 1.20 ml / g or more include, for example, clay (some grades), calcined clay, aluminum hydroxide (some grades), calcium carbonate (some grades). , Calcium sulfate, magnesium carbonate, amorphous silica, satin white, talc, calcium silicate, diatomaceous earth, plastic pigment, urea resin and the like.

The pigment used in the mixture as a pigment having a specific sedimentation volume of 1.20 ml / g or more is a pigment for coated paper which is commonly used in combination with the above pigments and has a specific sedimentation volume of 1.20 ml / g or less. For example, clay, aluminum hydroxide, calcium carbonate, titanium dioxide, barium sulfate, zinc oxide, etc. are appropriately used.

The cast coat for aqueous gravure printing of the present invention
In a coating liquid composition for paper, it is an essential condition to include an aqueous urethane resin as an adhesive. Adhesives other than the water-based urethane resin include water-soluble polymers having adhesive properties, such as casein, oxidized starch, phosphoric acid esterified starch, enzyme-modified starch, acetic acid esterified starch, soybean protein, synthetic protein, and carboxymethylcellulose. 1 to 25 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the pigment.

In particular, it is preferable to use at least one of casein, soybean protein and synthetic protein in combination from the viewpoint of releasability from the cast drum and printability.

A latex such as a styrene-butadiene latex, an acrylic latex, an acrylic-butadiene latex, an acrylonitrile-butadiene latex, or a vinyl acetate latex, which is generally used as a water-dispersible adhesive, is used in combination if necessary. You may.

When used in combination, the total amount of adhesive is 100 for all pigments.
The solid content is limited to 8 to 50 parts by weight with respect to parts by weight.
If it is less than the lower limit, the strength of the coating layer is weak, and if it exceeds the upper limit, the ink absorbency is deteriorated. The combined proportion of water-dispersible adhesives (latex) other than the water-based urethane resin is preferably 15% by weight or less of the water-based urethane resin, and above this range, the effect of the water-based urethane resin decreases.

In addition to the above-mentioned pigments and adhesives, a dispersant, a defoaming agent, and a defoaming agent may be added, if necessary, in the coating liquid composition used for the cast coated paper for aqueous gravure printing of the present invention.
Various auxiliaries such as a colorant, a water-proofing agent, a release agent, a fluidity modifier, and a coagulant can be appropriately mixed and used.

When the above-mentioned coating liquid composition is coated on a paper substrate, a coater commonly used in the production of general coated paper, such as a blade coater or an air knife coater, is used. -,
Roll coater, river roll coater, bar coater, carter coater, die slot coater, gravure coater, chanplex coater, etc. Using a coater provided with the coating device, the coating is applied in one layer or in multiple layers. The solid content concentration of the coating liquid at that time is 20 to 7
Although it is in the range of 0% by weight, this concentration is appropriately adjusted depending on the type and speed of the coater.

As the paper base material, a basis weight of 30 to 400 g / m ² which is used for general coated paper for printing and cast coated paper.
The base paper of the paper base or the paper board base of the range is used, but the papermaking method is not particularly limited, and it may be acidic papermaking, neutral papermaking, single-layer papermaking, or multi-layer papermaking. Of course, it is also possible to use a medium-quality raw paper containing mechanical pulp or waste paper pulp in an amount of about 10% by weight or more based on all pulp components.
Further, the undercoating of the above paper base material, the coated paper with the back surface of the cast coating layer having a general pigment coating, or one surface (back surface) of the paper base material is improved in glossiness by a mirror finishing method. Cast coated paper or the like can also be used as the paper substrate.

The coating amount of the coating liquid composition on the paper substrate is 10 to 50 g / m ² in terms of dry weight, but it is 15 to 30 g / m in view of the target quality of the coated paper and the intended use. ^It is desirable to adjust within the range of ² .

The degree of drying of the coated paper varies depending on the type of paper base material, the type of coating liquid composition, etc., but when the cast finish is carried out by the rewet method, the water content is 2 to 10.
It is dried in the range of wt%, preferably in the range of 3-8 wt%.

The coated paper after drying is subjected to a smoothing treatment such as a machine calender, a super calender and a gloss calender, if necessary, which is a characteristic of cast coated paper. Obviously, it is necessary to avoid excessive treatment that significantly impairs bulkiness and rigidity.

In the case of the rewet method, the coating layer is rewetted, and a pressing pressure of 50 to 80 kg / c is applied to the mirror-finished drum surface heated to 100 to 120 ° C.
It is pressed with m to give gloss and smoothness.

The re-wetting liquid for re-wetting includes, for example, fresh water, hot water, hot water, aqueous solution containing a release agent, soda citrate, zinc sulfate, calcium formate, calcium acetate, calcium chloride, magnesium formate. A rewetting liquid such as an aqueous solution containing amines such as magnesium acetate, magnesium chloride, or dicyandiamide is used. Preferably, an aqueous solution of calcium salt or magnesium salt of formic acid, acetic acid, chloride, sulfuric acid or the like is used.

By using the above calcium salt or magnesium salt aqueous solution, the ink drying property and the ink color density are further improved, and the releasability from the cast drum is also improved.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples, but of course the present invention is not limited thereto. Also, the parts and% used below
Indicates the parts by weight and the weight% of the active ingredient per 100 parts by weight of the pigment, unless otherwise specified.

Example 1 As a pigment, 60 parts of clay (manufactured by Engelhardt; UW-90, specific sedimentation volume 1.08 ml / g), calcium carbonate (manufactured by Shiraishi Kogyo; Brilliant 15, specific sedimentation volume 1.39)
ml / g) to 40 parts of polyacrylic acid soda 0.4
And 0.1 part of a mineral oil-based defoaming agent were added, and a pigment slurry having a solid content concentration of 58% was prepared using a coalescing disperser. Furthermore, 14 parts of casein obtained by adding ammonia as a water-soluble polymer as an adhesive component and heating and dissolving, and 12 parts of an aqueous urethane resin (manufactured by Teikoku Chemical Industry Co .; SL-1930) and 1.5 parts of calcium stearate, Finally, water was added to prepare a paint having a solid content of 35%. The resulting coating material was applied to a high-quality base paper (100 g / m @ 2 of tsubo) using a Mayer bar so that the coated amount was 25 g / m @ 2 on one side, dried with hot air, and then a 2% calcium formate aqueous solution was applied by the rewetting method. The coating layer was re-wetted using and was passed through a cast drum. At this time, the surface temperature of the cast drum was 110 ° C. and the pressing pressure was 50 kg / cm to obtain cast coated paper.

Examples 2 to 5 Calcium carbonate (Brilliant 15) or rewetting liquid used in Example 1 was used as Example 2 in calcium carbonate (manufactured by Okutama Kogyo; Tamapal 222H, specific sedimentation volume 1.42 ml / g). ), The rewetting liquid was added to a 2% aqueous solution of magnesium formate as Example 3 and made of clay (manufactured by Diklite; B).
Kaolin, specific sedimentation volume of 1.51 ml / g, calcium carbonate as Example 4 (manufactured by Okutama Kogyo; Tamapar 12)
3, specific sedimentation volume of 2.00 ml / g), as Example 5 calcined clay (manufactured by Seal; Kao Cal, specific sedimentation volume of 2.05 m)
The coating material was adjusted in the same manner as in Example 1 except that the content was changed to 1 / g) to obtain cast coated paper.

Examples 6 and 7 The pigment used in Example 1, Cray (UW-90),
Same as Example 1 except that the compounding amount of calcium carbonate (Brilliant 15) was changed to 90 parts for clay and 10 parts for calcium carbonate in Example 6, 20 parts for clay and 80 parts in calcium carbonate for Example 7, respectively. The coating material was adjusted by the above procedure to obtain cast coated paper.

Examples 8 to 11 The aqueous urethane resin (SL-19 used in Example 1)
The compounding amount of 30) was used as Example 8 (manufactured by Teikoku Kagaku Sangyo;
SL-2108) 2 parts, as Example 9 (SL-210)
8) 20 parts, and further 2 parts of styrene-butadiene latex (DL-636 manufactured by Asahi Kasei) as Example 10 (S
L-1930) 5 parts, as Example 11 (SL-193
0) The coating material was adjusted in the same manner as in Example 1 except that the content was changed to 30 parts to obtain cast coated paper.

Example 12 An undercoat layer (pigment; UW-90) was used as a coated base paper.
/ Ace 25 = 50/50 starch / SBR latex = 4
/ 12, coating amount 10g / m ² ) with medium quality coated paper (bleached chemical pulp 60%, bleached mechanical pulp 20%, deinking pulp 2
0%, tsubo 136g / m ² ) and coating amount 13g
Except for using / m ^2, to adjust the coating in the same operation as in Example 1 Cast co - give the door sheet.

Example 13 In Example 1, 90 parts of clay (made by Ceil; Caobrite, specific sedimentation volume 1.13 ml / g), urea resin (made by Mitsui Toatsu Chemicals; Le C-120, 5 parts of specific sedimentation volume 6.64 ml / g, synthetic silica (manufactured by Mizusawa Chemical;
Mizukacil P-78D, specific sedimentation volume 4.51 ml / g)
5 parts, the adhesive component was changed to 25 parts of water-based urethane resin (manufactured by Teikoku Chemical Industry; SL-2106), and the water-soluble polymer was changed to 7 parts of phosphate esterified starch (manufactured by Nippon Shokuhin Kogyo; MS-4600). The coating material was adjusted in the same manner as in Example 1 to obtain cast coated paper.

Examples 14 and 15 In Example 1, as Example 14, the rewetting liquid was added to a 3% zinc sulfate solution, and as Example 15, casein was added to soy protein (Protein Technologies International; The coating material was adjusted in the same manner as in Example 1 except that the content was changed to 10 parts.

Comparative Example 1 The pigment used in Example 1, Cray (UW-90),
A coating material was prepared in the same manner as in Example 1 except that the blending amount of calcium carbonate (Brilliant 15) was changed to 95 parts of clay and 5 parts of calcium carbonate to obtain cast coated paper.

Comparative Examples 2 to 4 Calcium carbonate (Brilliant 15) used in Example 1 was used as Comparative Example 2 in clay (manufactured by Huber; HG).
90, specific sedimentation volume 1.02 ml / g), calcium carbonate (made by Dowa Calfine; Ace 25, specific sedimentation volume 1.11 ml / g) as Comparative Example 3, and structured kaolin (Engelhard) as Comparative Example 4. (Manufactured by Ixilon, specific sedimentation volume 1.19 ml / g) except that the coating material was adjusted in the same manner as in Example 1 to obtain cast coated paper.

Comparative Example 5 The pigment used in Example 1, Cray (UW-90),
A coating material was prepared in the same manner as in Example 1 except that the blending amount of calcium carbonate (Brilliant 15) was changed to 10 parts for clay and 90 parts for calcium carbonate to obtain cast coated paper.

Comparative Examples 6 and 7 The pigment used in Example 1 was used in Comparative Example 6 as 100 parts of calcined clay (kaocar) and as Comparative Example 7 in synthetic silica (manufactured by Mizusawa Chemical Co .; Mizukasil P-604, specific sedimentation volume 2). ．
(97 ml / g) The coating material was adjusted in the same manner as in Example 1 except that the amount was changed to 100 parts to obtain cast coated paper.

Comparative Example 8 Water-based urethane resin (SL-19 used in Example 1)
30) to styrene-butadiene latex (DL-6
36) A coating material was prepared in the same manner as in Example 1 except that the content was changed to 12 parts to obtain cast coated paper.

Comparative Example 9 Aqueous urethane resin (SL-2 used in Example 13
106) to styrene-butadiene latex (DL-
A coating material was prepared in the same manner as in Example 13 except that the cast coated paper was obtained.

Comparative Example 10 50 parts of clay (UW-90) as a pigment, calcium carbonate (manufactured by Okutama Kogyo; TP-222HS, specific sedimentation volume 1.
42 ml / g) 50 parts and 0.2 parts of sodium pyrophosphate as a dispersant are added to water and dispersed to prepare a pigment slurry having a concentration of 70%.
Was adjusted. Next, with respect to 100 parts of the pigment, 0.2 part of tributyl phosphate as a defoaming agent, 0.1 part of Pluronic L-61 (manufactured by Asahi Denka Co., Ltd.), 1 part of calcium stearate as a release agent, 5 parts of casein as an adhesive, and 2 parts of water-based urethane resin (Mitsui Toatsu Chemicals; Olester UD500)
Styrene-butadiene latex (Mitsui Toatsu Chemicals;
13 parts of polylac 515) was added, and finally water was added to prepare a paint having a solid content of 50%. This is 100 g of basis weight /
After coating was dried so that the coating amount 23 g / m ² on a high-quality base paper of m ^2, surface temperature 96 to 98 ° C. gave rewetting solution
The cast drum was treated with a press drum of 100 kg / cm to obtain cast coated paper.

Comparative Example 11 As a pigment, 50 parts of clay (UW-90), 30 parts of calcium carbonate (TP-222HS), aluminum hydroxide (manufactured by Showa Denko; Hydilite H42, specific sedimentation volume 1.1)
(5 ml / g) 20 parts, 0.3 part of Aron T-40 as a dispersant is added to water and dispersed, and a pigment slurry having a concentration of 70% is prepared.
Was adjusted. Next, with respect to 100 parts of the pigment, 0.2 part of tributyl phosphate and Pluronic L-61 as an antifoaming agent were added.
1 part, 1 part of calcium stearate as a release agent, 5 parts of an aqueous urethane resin (manufactured by Mitsui Toatsu Kagaku; Oresta-UD500) as an adhesive, 45 parts of styrene-butadiene latex (manufactured by Mitsui Toatsu Kagaku; Polylac 518) Then, water was added at the end to prepare a paint having a solid content of 60%.
This is applied to a high-quality base paper with a basis weight of 100 g / m ² and a coating amount of 25 g
It was coated so as to have a surface area of m ² and immediately treated with a cast drum having a surface temperature of 96 to 98 ° C. and a press pressure of 20 kg / cm to obtain cast coated paper.

Comparative Example 12 50 parts of clay (UW-90) as a pigment, 50 parts of calcium carbonate (TP-222HS), 0.2 part of sodium pyrophosphate as a dispersant, and 0.1 part of Pluronic L-61. Was added to water and dispersed to prepare a pigment slurry having a concentration of 70%.
Next, with respect to 100 parts of the pigment, 0.2 part of CMC (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a water retention agent, 1 part of calcium stearate as a release agent, and an aqueous urethane resin as an adhesive (Mitsui Toatsu Chemicals; Part, JP-A-6
13 parts of latex described in -2299 was added, and finally water was added to prepare a coating material having a solid content of 50%. Weigh this 1
200 g / m ² of coated so that the coating amount 20 g / m ² on a high-quality base paper, the cast drum having a surface temperature of 96 to 98 ° C. giving rewetting solution, casting and treated with a press pressure of 150 kg / cm co - DOO Got the paper.

Comparative Example 13 As a pigment, 60 parts of clay (UW-90), 40 parts of calcium carbonate (TP-222HS), and 0.5 parts of sodium polyacrylate were added to water and dispersed to prepare a pigment slurry having a concentration of 65%. Was adjusted. Then, with respect to 100 parts of the pigment, 0.5 part of tributyl phosphate as an antifoaming agent, 1 part of ammonium stearate as a releasing agent, and an anionic water-based urethane resin as an adhesive (Mitsui Toatsu Chemical; Barrier Star X
UD2120) 5 parts, styrene-butadiene copolymer (Asahi Kasei; L-1537) 20 parts, and zinc sulfate 1 part were added to prepare a paint having a pH of 8 and a solid content of 45% with water and ammonia. This was coated on a high-quality base paper having a basis weight of 100 g / m ² so that the coating amount was 20 g / m ² , and dried. Next, the coated surface of the coated paper was treated with a rewetting liquid consisting of a 1% polyethylene emulsion and treated with a cast drum having a surface temperature of 105 ° C. and a press pressure of 200 kg / cm to obtain a cast coated paper.

Comparative Example 14 80 parts of clay (UW-90) as a pigment, calcium carbonate (manufactured by Phimatec; FMT-90, specific sedimentation volume of 0.
99 ml / g) 7 parts, calcium carbonate (manufactured by Shiraishi Kogyo; Callite KT, specific sedimentation volume 1.51 ml / g) 13 parts,
Alon T-400.4 parts are added to water and dispersed, and the concentration is 65%.
The pigment slurry of was prepared. Next, based on 100 parts of the pigment, an aqueous urethane resin (manufactured by Mitsui Toatsu Chemicals;
D100N) 27 parts, styrene / butadiene copolymer (L-1537) 7 parts, wax emulsion (manufactured by San Nopco) 1.4 parts, calcium formate 0.7 part, non-phosphoric acid antifoaming agent 0.1 part, fluorescent dye 0.3 parts, water is added sequentially,
After stirring well, the pH was made alkaline with 25% aqueous ammonia to prepare a paint having a solid content of 40%. This was coated on a high-quality base paper having a basis weight of 100 g / m ² so that the coating amount was 23 g / m ² , and dried. Next, a 0.3% zinc sulfate aqueous solution was sprayed onto the coated surface of this coated paper and pressure-bonded to a cast drum having a surface temperature of 110 ° C. to obtain a cast coated paper.

Quality Evaluation Method The quality evaluation of the thus obtained cast coated paper for aqueous gravure printing was carried out as follows. Ink drying property: Using a Mayer bar, an aqueous gravure ink (black) was applied to a cast coated paper at 23 g / m @ 2, and the time until the gloss of the ink disappeared (setting time) was measured. The shorter the time is, the better the ink drying property is. In the present invention, the ink drying property is set to 10 seconds or less.

Ink color density: 100 after printing with an aqueous gravure ink (magenta) using an IGT Helio printer
The ink density in the% solid area was measured with a Macbeth densitometer. The higher the Macbeth density, the higher the ink color density, and in the present invention, the ink color density of 1.90 or higher was targeted. The results obtained in Examples 1 to 15 are shown in Table 1 and Comparative Examples 1 to 14
The results obtained in Step 2 are shown in Table 2.

[0060]

[Table 1]

[0061]

[Table 2]

[0063]

As can be seen from Tables 1 and 2, the aqueous urethane resin contains a pigment having a specific sedimentation volume of 1.20 ml / g or more in the range of 10 to 80 parts by weight based on 100 parts by weight of the total pigment. In an amount of 1 to 30 parts by weight per 100 parts by weight of the pigment, and a water-soluble polymer is further added to the pigment 100.
The cast coat paper for water-based gravure printing of the present invention obtained by applying a coating composition containing 1 to 25 parts by weight per part by weight and casting it is excellent in ink drying property during water-based gravure printing, and Ink color density is high. (Examples 1 to 15) When the rewetting liquid is an aqueous solution of calcium salt or magnesium salt, the ink drying property and the ink color density are further improved.

However, the specific sedimentation volume in all pigments was 1.20.
If the content of the pigment of ml / g or more is less than 10% by weight (Comparative Example 1), or if the pigment having the specific sedimentation volume of less than 1.20 ml / g is used, the ink drying property is deteriorated (Comparative Examples 2 to 2).
4), even if the specific sedimentation volume of the pigment and the content of the aqueous urethane resin are appropriate, the content of such pigment is high (Comparative Examples 5 to 7), and the specific sedimentation volume of the pigment and the content of Even if the water content is appropriate, if the aqueous urethane resin is not used (Comparative Examples 8 and 9), the color density of the ink becomes low, and the water-soluble polymer is not used in combination, or the styrene-butadiene latex is used in combination, When the ratio is more than 15% by weight based on the aqueous urethane resin, the ink drying property is significantly deteriorated and the effect of the aqueous urethane resin is reduced (Comparative Examples 10 to 14).

Cast Coat for Aqueous Gravure Printing of the Invention
The printing paper has a high drying speed of the water-based gravure ink, a high ink color density, and enables high-speed printing of a print image with good reproducibility.

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Claims (4)

[Claims] 1. A cast coat paper, which comprises a coating layer comprising a pigment and an adhesive as main components and is cast-finished, and has a specific sedimentation volume of 1.20 ml / g in 100 parts by weight of all pigments as the pigment. The ratio of the above pigments is 10
Using 80 parts by weight of the pigment, 1 to 30 parts by weight of an aqueous urethane resin as the adhesive agent per 100 parts by weight of the pigment, and 1 to 100 parts by weight of the water-soluble polymer per 100 parts by weight of the pigment.
A cast coat paper for water-based gravure printing, characterized by being provided with a coating layer containing an adhesive containing 25 parts by weight as an essential adhesive component and then being cast-finished. 2. The cast coated paper for aqueous gravure printing according to claim 1, wherein the water-soluble polymer is at least one of casein and / or soybean protein and / or synthetic protein. 3. When latex is used together as a water-dispersible adhesive other than the aqueous urethane resin, the combined proportion of the latex is 15% by weight or less of the aqueous urethane resin. The cast coated paper for water-based gravure printing according to 2. 4. A cast coated paper for aqueous gravure printing according to claim 1, 2 or 3, wherein a rewetting method is used in the cast finishing and the rewetting liquid is an aqueous solution of calcium salt and / or magnesium salt.