JP2977575B2 - Coating composition for high gloss paper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating composition for high gloss paper, and particularly to a coating composition for high gloss paper capable of producing a high gloss paper having an excellent glossy surface. It relates to a high gloss paper obtained by coating it.

[Conventional technology]

For example, as a method for producing a general cast coated paper having a glossiness of 85 to 90 according to JIS P-8142, a coating composition for coated paper is applied to a base paper, and pressed to a mirror-surface drum heated in a wet state. A direct method of drying and drying, a coagulation method of coagulating a wet coated paper coating composition applied to a base paper and then pressing and drying it with a heating mirror-surface drum, and a coating method of applying a coated paper coating composition to a base paper once After drying or semi-drying, there is a re-wetting method or the like in which the sheet is wetted again and dried by pressure bonding with a heated mirror drum.

In the production method of these cast coated papers, a coating composition for coated paper mainly comprising a coated pigment and an adhesive is pressed and dried on a heating drum in a wet state and peeled from a mirror surface to obtain a high gloss. In that a uniform cast surface is obtained. Further, for the purpose of improving the quality and productivity of the obtained cast coated paper, a coating composition for coated paper containing a pigment and an adhesive as a main component is coated and dried in advance on the surface of a general coated paper or a lightweight coated paper. There is also a method in which a small amount of a coating composition for cast-coated paper is applied, pressed against a heating drum, dried, and peeled from a mirror surface to obtain a high-gloss and uniform cast surface.

In any method, usually, a water-soluble polymer having an adhesive property, for example, casein, oxidized starch, phosphated starch, soybean protein, carboxymethylcellulose, hydroxyethylcellulose and the like are 5 to 15 parts by weight based on 100 parts by weight of the pigment. Used in parts by weight.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION The present invention provides a coating composition for a high gloss paper which can produce a high gloss paper having a high gloss level and a uniform cast surface, such as 100, which has not existed before.

[Means for solving the problem]

The present invention provides a coating composition containing a pigment and an adhesive as main components, wherein the adhesive copolymerizes an aliphatic conjugated diolefin monomer and an olefin aromatic monomer and / or a monoolefin monomer. Solid content of the polymer latex and / or emulsion obtained by
And a water-soluble urethane resin having a solid content of 30 to 5% by weight. The coating composition for high gloss paper is characterized by not using a water-soluble polymer having adhesiveness. This makes it possible to manufacture a high gloss paper having an unprecedented excellent surface gloss.

Further, in the present invention, it is intended to provide a coating composition for high gloss paper having the same effect without using an aliphatic conjugated diolefin-based monomer, and further obtained by coating these compositions. This is to provide high gloss paper.

When the present invention is described in detail, urethane resins that can be used in combination with a polymer latex, a polymer emulsion, or a mixture of a polymer latex and a polymer emulsion used as an adhesive include emulsions, colloidal dispersions, and the like. A polyurethane resin which can be stably present in water in the form of an aqueous solution or the like is used.

Examples of the aqueous urethane resin include isocyanates such as toluene diisocyanate, 4,4'-phenylmethane diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like, neopentyl glycol, 1,4-butanediol, 1,6 Nonionic type obtained by performing a urethane reaction with a polyol such as hexanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyester polyol, polycarbonate polyol, polyethylene glycol, etc., for example, tertiary such as N-methyldiethanolamine Cationic type obtained using an amine, and, for example, anionic type obtained using dimethylolpropionic acid and the like. . Furthermore, those obtained by polymerizing with amines such as triethylamine and dimethylethanolamine, or those obtained by crosslinking using a water-soluble amino resin such as methylated melamine resin, aziridine, epoxy resin, zinc complex, etc. Good.

As the polymer latex that can be used in the present invention, for example, SBR latex, MBR latex, those referred to as SMBR latex, similar to the latex generally used as an adhesive in a paper pigment coating composition Consists of components.

However, in the present invention, the aliphatic conjugated diolefin-based monomer is preferably 15% of the total constituent polymer components.
To 35% by weight, more preferably 20 to 30% by weight, and preferably 85 to 65% by weight, more preferably 80 to 70% by weight, of all the constituent polymer components. %.

As the polymer component, preferably, butadiene, styrene and / or methyl methacrylate as main components, and other monomers copolymerizable therewith, if necessary, are used. Examples of the copolymerizable monomer include: aliphatic conjugated diolefin monomers such as isoprene and 2-chlorobutadiene; olefin aromatic monomers such as α-methylstyrene, chlorostyrene and dimethylstyrene; (meth) acrylic acid Monoolefinic monomers such as methyl, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, and (meth) acrylonitrile; and monomers such as vinyl acetate There is. Further, if necessary, for example, olefinic unsaturated hydroxy monomers such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate; acrylamide, methacrylamide, N-methylolacrylamide, N -At least one or a combination of two or more olefinically unsaturated amide monomers such as methylol methacrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide and the like can be used. These monomers are examples, and any other copolymerizable monomers can be used. A polymer latex or a polymer emulsion may be formed by a combination of such monomers, and both may be mixed and used.

In the present invention, a polymer emulsion comprising an olefinic aromatic monomer and / or a monoolefinic monomer can be used without using an aliphatic conjugated diolefinic monomer. In the use of the polymer emulsion, monomers other than the aliphatic conjugated diolefin-based monomer used in the production of the polymer latex are similarly used.

Examples of the aqueous urethane resin used in the present invention include JP-B-48-25435 and JP-A-59-1.
Utilizing an aqueous urethane resin produced by a method disclosed in Japanese Patent Publication No.
The resin is crosslinked by a crosslinking method disclosed in, for example, Japanese Patent No. 987 and can be used as an aqueous urethane resin having a resin solid content concentration of 30 to 40% by weight.

Pigments that can be used in the coating composition for cast-coated paper of the present invention include clay, light calcium carbonate, heavy calcium carbonate, titanium oxide, aluminum hydroxide, satin white, barium sulfate, used in ordinary coated paper. Inorganic pigments such as magnesium oxide, talc and colloidal silica, and / or organic pigments such as plastic pigments and white urea resin pigments can all be used, and usually two or more kinds are used in combination.

It is preferable to use the aqueous urethane resin and the polymer latex and / or emulsion as an adhesive in the range of 25 to 50 parts by weight based on 100 parts by weight of the pigment.

The present invention uses an aqueous urethane resin and a polymer latex and / or a polymer emulsion,
It is important not to use a water-soluble polymer having adhesive properties, such as casein, oxidized starch, phosphated starch, soybean protein, carboxymethylcellulose, or hydroxyethylcellulose, which is commonly used in coating compositions for cast-coated paper. When these water-soluble polymers are used, it is difficult to obtain a high gloss paper as the object of the present invention. However, it is effective to add auxiliaries such as an antifoaming agent, a dispersing agent, a waterproofing agent, a preservative, a coloring agent, a coagulant, and a releasing agent as necessary.

The thus-obtained high gloss paper coating composition is coated, for example, by a coating apparatus such as an air knife coater, a blade coater, a roll coater, or a bar coater in the same manner as a general coated paper production. However, the solid content concentration of the coating composition at this time is usually 40 to 65% by weight.

Further, as the base paper for strong glossy paper of the present invention, commonly used printing coated paper or cast coated paper basis weight 40 to 30
Use is made of high-quality paper, medium-quality paper, paperboard, etc., of 0 g / m2, and coated paper in which a coating composition has been previously applied to one or both sides and dried. The coating amount of the coating composition on these base papers is
Usually 10 to 25 g / m2 is applied on one side by dry weight. After being coated in this manner, a mirror surface is formed by a direct casting method, a solidification casting method, a re-wetting casting method, or a combination thereof.

[Action]

In the high gloss paper coating composition of the present invention, that is, the high gloss paper coating composition containing a pigment and an adhesive as main components, 5 to 30% by weight of an aqueous urethane resin as an adhesive, an aliphatic conjugated diolefin monomer There is no conventional high gloss paper obtained by applying a coating composition for high gloss paper using 70 to 95% by weight of a synthetic rubber latex or emulsion containing the same in a known manner and drying it by close contact drying with a mirror drum. It can be manufactured with high surface gloss and uniform surface image quality.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Parts and% used below are based on weight unless otherwise specified.

Example 1 Kaolin (product name: UW90, manufactured by Engelhardt USA) 50
Part, calcium carbonate (Okutama Kogyo: Tamapearl)
30 parts of TP222HS), 20 parts of aluminum hydroxide (manufactured by Showa Denko: trade name: Heidilite H42), and 0.3 parts of Aron T40 (manufactured by Toagosei) as a dispersant, and dispersed in water using a Cowles disperser. A 70% pigment slurry was prepared. Then, as an antifoaming agent, tributyl phosphate 0.2
Parts, Pluronic L-61 (Asahi Denka) 0.1 part, calcium stearate 1.0 part as a release agent, aqueous urethane resin (Mitsui Toatsu Chemicals: Olester UD500) 5 parts as an adhesive, SBR latex (Mitsui Toatsu Chemicals: Polylac 518) 45 parts were added, and finally, water was added to adjust the solid concentration to 60%, and the coating composition for high gloss paper of the present invention (hereinafter referred to as coating composition of Example 1) ). The viscosity of the obtained coating composition was measured using a BM type viscometer (manufactured by Tokyo Keiki) 25
It was measured at 60 ° C. and 60 rpm, and is shown in Table 1.

Examples 2 to 4 The aqueous urethane resin (trade name: Olester UD500N, manufactured by Mitsui Toatsu Chemicals) and latex (trade name: Polylac 518, manufactured by Mitsui Toatsu Chemicals) used in Example 1 are shown in Table 1. The three types of coating compositions for strong glossy papers of the present invention (hereinafter referred to as Examples 2 to 3) were added in the same manner as in Example 1.
4 paint composition).

Comparative Example 1 Example 1 except that 0.5 parts of an aqueous urethane resin (Mitsui Toatsu Chemical: trade name Olestar UD500) and 49.5 parts of SBR latex (Mitsui Toatsu Chemical: trade name Polylac 518) were used as the adhesive. Perform the same experiment as in
Also shown in the table.

Comparative Examples 2 and 3 In Comparative Examples 2 and 3, in order to clarify the effects of the aqueous urethane resin of the present invention and a synthetic rubber latex, a coating composition for a high gloss paper obtained by using a water-soluble polymer in combination. Here is an example.

As an adhesive, water-based urethane resin (Mitsui Toatsu Chemical:
The amounts shown in Table 1 of Orestar UD500 (trade name) and SBR latex (trade name: Polylac 518, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) were added. Further, 10 parts of casein which was dissolved by heating with ammonia water was added. Was added, and the coating compositions of Comparative Examples 2 and 3 were obtained in the same manner as in Example 1 except that the solid content concentration was adjusted to 50% so as to obtain the same viscosity.

Hereinafter, an experiment was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4 In Comparative Example 4, in order to clarify the combined effect of the aqueous urethane resin of the present invention and a polymer latex, an example of a coating composition for cast-coated paper using a polymer latex alone is shown.

Without using an aqueous urethane resin as an adhesive,
SBR latex (Mitsui Toatsu Chemicals: Polylac 5
18) An experiment was conducted in the same manner as in Example 1 except that 25 parts was added to obtain a coating composition of Comparative Example 4.

Hereinafter, an experiment was performed in the same manner as in Example 1, and the results are shown in Table 1.

Production Example of Strong Glossy Paper: The coating composition for cast-coated paper obtained in the above Examples and Comparative Examples was applied to a base paper having a basis weight of 64 g / m2 by using an air knife coater to apply each coating composition. By dry weight
Coating was performed to 25 g / m2, and the mixture was passed through a cast drum.
Cast drum diameter is 1800mm, press pressure is 20kg / c
m, drum surface temperature was 96-98 ° C.

The physical properties of the obtained high gloss paper were measured, and the results are shown in Table 1.

The glossiness was measured according to JIS P-8142.
The surface strength was printed by an RI printing tester (manufactured by Meisho Seisakusho), and the surface picking was observed. Observation of the surface picking was evaluated on a 10-point scale (10: good without surface picking, 1: poor picking occurred on the entire surface).

Example 5 Kaolin (product name: UW90, manufactured by Engelhardt USA) 50
Part, calcium carbonate (Okutama Kogyo: Tamapearl)
30 parts of TP222HS), 20 parts of aluminum hydroxide (manufactured by Showa Denko: Heidilite H42) and 0.3 part of Aron T40 (manufactured by Toagosei) as a dispersant, and dispersed in water using a Cowles disperser. A 70% pigment slurry was prepared. Next, 0.2 parts of tributyl phosphate as a defoaming agent, 0.1 parts of Pluronic L-61 (manufactured by Asahi Denka), 1.0 part of calcium stearate as a release agent, and an aqueous urethane resin as an adhesive (manufactured by Mitsui Toatsu Chemicals) : 5 parts of Orestar UD500 (trade name) and 45 parts of an acrylic emulsion (trade name: Bonlon 880, manufactured by Mitsui Toatsu Chemicals Co., Ltd.), and finally water was added to adjust the solid content to 60%. A coating composition for paper was obtained. Further, the viscosity of the obtained coating composition is determined by BM
Measured with a mold viscometer (Tokyo Keiki) 25 ° C, 60 rpm,
The results are shown in Table 2.

Examples 6 to 8 The water-based urethane resin used in Example 5 and the acrylic emulsion were added by weight as shown in Table 2, and the same operation as in Example 5 was carried out, and the coating composition 3 for high gloss paper of the present invention was obtained. Seeds (hereinafter referred to as Examples 6 to 8 paint compositions) were obtained.

Comparative Example 5 An experiment was conducted in the same manner as in Example 5 except that 0.5 parts of an aqueous urethane resin and 49.5 parts of an acrylic emulsion were used as an adhesive, and the results are shown in Table 2 together.

Comparative Examples 6, 7 Examples in which a water-soluble polymer is used in combination are shown.

As an adhesive, 10 parts of casein, which was heated and dissolved by adding aqueous ammonia, and an aqueous urethane resin and an acrylic emulsion in the amounts shown in Table 2 were added. Finally, water was added, and the solid content was adjusted to about the same value. Coating compositions of Comparative Examples 6 and 7 were obtained in the same manner as in Example 5, except that the concentration was adjusted to 50%.

Hereinafter, an experiment was conducted in the same manner as in Example 5, and the results are shown in Table 2.

Comparative Example 8 In Comparative Example 8, in order to clarify the combined effect of the aqueous urethane resin of the present invention and an acrylic emulsion, an example of a coating composition for cast-coated paper using an acrylic emulsion alone is shown.

Add 25 parts of acrylic emulsion as adhesive,
Finally, the same experiment as in Example 5 was carried out except that water was added to adjust the solid content concentration to 45%, to obtain a coating composition of Comparative Example 8.

Hereinafter, an experiment was conducted in the same manner as in Example 5, and the results are shown in Table 2.

[Effect of the Invention] According to the numerical values in Tables 1 and 2, the high gloss paper obtained by using the coating composition for high gloss paper according to the embodiment of the present invention has a cast surface excellent in gloss and surface strength. This indicates that the coating composition of the present invention is a useful coating composition that has never been used before.

Claims (3)

(57) [Claims] 1. A coating composition comprising a pigment and an adhesive as main components, wherein the adhesive copolymerizes an aliphatic conjugated diolefin monomer with an olefin aromatic monomer and / or a monoolefin monomer. Solid content of the polymer latex and / or emulsion obtained by
1. A coating composition for high gloss paper, which comprises 30% by weight and a solid content of 30 to 5% by weight of an aqueous urethane resin, and does not contain a water-soluble polymer having adhesiveness. 2. A coating composition comprising a pigment and an adhesive as main components, the solid content of a polymer emulsion obtained by copolymerizing an olefinic aromatic monomer and / or a monoolefinic monomer as the adhesive. A highly glossy paper coating composition comprising 70 to 95% by weight and a solid content of 30 to 5% by weight of an aqueous urethane resin. 3. A high gloss paper obtained by applying the composition according to claim 1 or 2.