JPH03252473A - Coating compound composition for high gloss paper - Google Patents

Abstract

PURPOSE:To obtain the title composition useful for paper having excellent gloss and surface strength, consisting essentially of pigment and adhesive which comprises a specific polymer latex, etc., and an aqueous urethan resin in a specific ratio. CONSTITUTION:The objective composition which is a coating compound composition consisting essentially of pigment (e.g. clay) and an adhesive wherein the adhesive comprises 70-95wt.% solid content of latex and/or emulsion of a polymer prepared by copolymerizing an aliphatic conjugated diolefin-based monomer [e.g. butadiene; the amount thereof used is preferably 20-30wt.% in the polymer component] with an olefin-based aromatic monomer (e.g. alpha-methylstyrene) and/or a monoolefin-based monomer [e.g. methyl (meth)acrylate] and 30-5wt.% solid content of an aqueous urethane resin.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a coating composition for highly glossy paper, and particularly a coating composition for highly glossy paper that can produce highly glossy paper having an excellent glossy surface, and It relates to highly glossy paper obtained by coating it.

[Prior art] For example, the gloss level according to JIS P-8142 is 85~
General methods for producing cast-coated paper having a coating composition of 90 are the direct method, in which a coating composition for coated paper is applied to a base paper, and the coated paper is pressed onto a heated specular drum in a wet state, and then dried; A coagulation method involves coagulating a coating composition for coated paper and then pressing and drying it with a heated specular drum.The coating composition for coated paper is applied to a base paper, dried or semi-dried, and then re-wetted to produce a heated specular surface. There is a rewetting method that involves pressing and drying with a drum.

In all of these methods for producing cast coated paper, a coated paper coating composition containing pigments and adhesives as main components is pressed onto a heated drum in a wet state, dried, and then peeled off from the mirror surface to achieve high gloss. The common feature is that it provides a uniform casting surface. In addition, in order to improve purchasing and productivity of the resulting cast coated paper, the surface of general coated paper or lightweight coated paper that has been coated with a coated paper coating composition containing pigments and adhesives as main components and dried. Another method is to apply a small amount of a coating composition for cast-coated paper, press it onto a heated drum, dry it, and peel it off from the mirror surface to obtain a high-gloss, uniform cast surface.

In either method, a water-soluble polymer having adhesive properties, such as casein, oxidized starch, phosphoric ester starch, soybean protein, carboxymethyl cellulose, hydroxyethyl cellulose, etc., is usually added at 5 to 15 parts by weight per 100 parts by weight of the pigment. Parts by weight are used together.

[Problem to be solved by the invention]

The present invention provides a coating composition for highly glossy paper that can produce highly glossy paper having an unprecedented high gloss level of 100 and a uniform cast surface.

[Means to solve the problem]

The present invention relates to a coating composition containing a pigment and an adhesive as main components, wherein the adhesive is a copolymer of an aliphatic conjugated diolefin monomer, an olefin aromatic monomer and/or a monoolefin monomer. The solid content of the polymer latex and/or emulsion obtained by
5% by weight, and the solid content of water-based urethane resin is 30-5% by weight.
The present invention provides a coating composition for highly glossy paper, which makes it possible to produce highly glossy paper with unprecedented surface gloss.

In addition, the present invention provides a coating composition for highly glossy paper that achieves the same effect without using an aliphatic conjugated diolefin-based paint. This provides highly glossy paper.

To explain the present invention in detail, the urethane resin 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 includes an emulsion,
A polyurethane resin that can exist stably in water in the form of colloidal dispersion, aqueous solution, etc. 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 neopentyl glycol, 4-butane diol, 1.6 Nonionic type, such as N-methyljetanolamine, etc. obtained by performing a urethane reaction with polyols such as hexanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyester polyol, polycarbonate polyol, polyethylene glycol, etc. Examples include a cation type obtained using a tertiary amine and an anion type obtained using, for example, dimethylol propionic acid. In addition, polymers made with amines such as triethylamine and dimethylethanolamine, water-soluble amino resins such as methylated melamine resins, aziridine, epoxy resins, and
It may also be obtained by crosslinking using a complex or the like.

Examples of the vine polymer latex used in the present invention include SBR latex, MBR latex, and SMBR latex, which are similar to latexes commonly used as adhesives in paper nodding coating compositions. It consists of the following ingredients.

However, in the present invention, the aliphatic conjugated diolefin monomer preferably contains 15% of the total constituent polymer components.
~35% by weight, more preferably 20 to 30% by weight, and the olefinic aromatic monomer and/or monoolefinic monomer preferably accounts for 8% of the total constituent polymer components.
It is 5 to 65% by weight, more preferably 80 to 70% by weight.

The main components of the polymer are preferably butadiene, styrene and/or methyl methacrylate, and other monomers copolymerizable with these are used as necessary. The copolymerizable monomers include, for example, aliphatic conjugated diolefin monomers such as isoprene and 2-chlorobutadiene; olefinic aromatic monomers such as α-methylstyrene, chlorostyrene, and dimethylstyrene; ) Monoolefinic monomers such as methyl acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, and (meth)acrylonitrile; and vinyl acetate. There are thousands of them. In addition, if necessary, for example, olefinically unsaturated hydroxy monomers such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, niacrylamide, methacrylamide, N-methylolacrylamide, At least one kind or a combination of two or more kinds of olefinically unsaturated amide monomers such as N-methylolmethacrylamide, N-methoxymethylmethacrylamide, N-methoxymethylmethacrylamide, etc. can be used. These monomers are just examples, and other copolymerizable monomers can be used. A polymer latex or a polymer emulsion may be formed by a combination of such monomers, and a mixture of the two may also be used.

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

As the water-based urethane resin used in the present invention, water-based urethane resins manufactured by methods disclosed in, for example, Japanese Patent Publication No. 48-25435 and Japanese Patent Application Laid-open No. 59-138211, etc., are used. It is crosslinked by the crosslinking method disclosed in Publication No. 49-987 etc., and usually has a resin solid content concentration of 30
It can be used as a water-based urethane resin of up to 40% by weight.

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

The aqueous urethane resin and polymer latex and/or emulsion that are adhesives are preferably used in an amount of 25 to 50 parts by weight based on 100 parts by weight of the pigment.

By using a water-based urethane resin and a polymer latex and/or a polymer emulsion, the present invention can produce water-soluble polymers with adhesive properties, such as casein, oxidized starch,
One of its characteristics is that it does not contain phosphoric acid ester starch, soybean protein, carboxymethyl cellulose, hydroxyethyl cellulose, etc. When these water-soluble polymers are used, it is necessary to use strong gloss paper, which is the object of the present invention. difficult to obtain. However, antifoaming agents, dispersants,
It is effective to add auxiliary agents such as waterproofing agents, preservatives, coloring agents, coagulants, and mold release agents as necessary.

The coating composition for highly glossy paper thus obtained is coated with coating equipment such as an air knife coater, a plate coater, a roll coater, or a bar coater.
Coating is carried out in the same manner as in the production of coated paper, but the solid content concentration of the coating composition at this time is usually 40 to 65% by weight.

In addition, the base paper for highly glossy paper of the present invention includes generally used printing coated paper and cast coated paper with a basis weight of 40 to 3.
00 g/m2 high-quality paper, medium-quality paper, paperboard, etc., and coated paper, etc., which are coated with a coating composition on one or both sides and dried, are used. The coating amount of the coating composition on these base papers is usually 10 to 25 g/m 2 on one side in terms of dry weight. After being coated in this way, direct casting method,
A mirror surface is formed by a solidification casting method, a rewetting casting method, or a combination thereof.

[For production]

In the coating composition for highly glossy paper of the present invention, that is, the coating composition for highly glossy paper containing a pigment and an adhesive as main components, 5 to 30% by weight of an aqueous urethane resin and an aliphatic conjugated diolefin monomer are used as the adhesive. A highly glossy paper that is obtained by applying a highly glossy paper coating composition containing 70 to 95% by weight of a synthetic rubber latex or emulsion using a known method and drying it in close contact with a mirror drum is unprecedented. It has high surface gloss and can be manufactured with uniform surface image quality.

[Examples] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not equally limited by these.

In addition, parts and percentages used below are based on weight unless otherwise specified.

Example 1 Kaolin (manufactured by Engelhard, USA: trade name UW90)
50 parts, 30 parts of calcium carbonate (manufactured by Okutama Kogyo, trade name Tama Pearl TP222H3), 20 parts of aluminum hydroxide (manufactured by Showa Denko, trade name Hisilite H42), and as a dispersant, 0.3 parts of trade name Aron T40 (manufactured by Toagosei). of water and dispersed in water using a colorless dispersion machine to obtain a concentration of 70%.
A pigment slurry was prepared. Next, 0.2 parts of tributyl phosphate, trade name Pluronic L-6, was added as an antifoaming agent to this.
1 (manufactured by Asahi Denka) 0.1 part, calcium stearate 1.0 part as a mold release agent, water-based urethane resin (manufactured by Mitsui Toatsu Chemicals: trade name Orestar UD500) 5 parts as an adhesive, S
Add 45 parts of BR latex (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Polylac 518), and finally add water to make the solid content concentration 6.
The coating composition for highly glossy paper of the present invention (hereinafter referred to as Example 1 coating composition) was obtained by adjusting the coating composition to 0%. The viscosity of the obtained coating composition was measured using a BM type viscometer (manufactured by Tokyo Keiki) at 25°C.
Measured at 60 rpm and shown in Table 1.

Examples 2 to 4 The water-based urethane resin (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Niorestar UD50ON) and the latex (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Polylac 518) used in Example 1 were weighed as shown in Table 1. Three kinds of coating compositions for highly glossy paper of the present invention (hereinafter referred to as coating compositions of Examples 2 to 4) were obtained in the same manner as in Example 1.

Comparative Example 1 As an adhesive, 0.5 part of water-based urethane resin (manufactured by Mitsui Toatsu Chemicals: trade name OLESTAR UD500) and SBR latex (manufactured by Mitsui Toatsu Chemicals: trade name Polylac 5 j8) were used.
The experiment was conducted in the same manner as in Example 1 except that 49.5 parts were used, and the results are also listed in Table 1.

Comparative Example 2.3 In Comparative Examples 2 and 3, the aqueous urethane resin of the present invention and
In order to clarify the effects of synthetic rubber latex, etc., an example of a highly glossy paper coating composition obtained by using a water-soluble polymer in combination will be shown.

As an adhesive, the amounts shown in Table 1 of water-based urethane resin (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name: OLESTAR UD500) and SBR-based latex (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name Polylac 518) were added, and ammonia water was added. The coating compositions of Comparative Examples 2 and 3 were prepared in the same manner as in Example 1, except that 10 parts of casein dissolved by heating were added, and finally water was added to adjust the solid content concentration to 50% so that the viscosity was about the same. I got something.

Hereinafter, experiments were conducted in the same manner as in Example 1, and the results are also listed in Table 1.

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

S without using water-based urethane resin as adhesive.
A coating composition of Comparative Example 4 was obtained by carrying out an experiment in the same manner as in Example 1, except that 25 parts of BR latex (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name: Polylac 518) was added.

Hereinafter, experiments were conducted in the same manner as in Example 1, and the results are also listed in Table 1.

Production Example of Highly Glossy Paper The coating compositions for cast coated paper obtained in the above Examples and Comparative Examples were applied to a base paper with a basis weight of 64 g/m2 using an air knife coater to reduce the coating amount of each coating composition after drying. It was coated to a weight of 25 g/m2 and passed through a cast tram. The diameter of the cast drum is 1800 mm, the press pressure is 20 kg/cm, and the drum surface temperature is 96-98
It was carried out at ℃.

In addition, the physical properties of the obtained highly glossy paper were measured, and the results are shown in Table 1.

Note that the glossiness was measured according to JIS P-8142. The surface strength was evaluated by performing printing using an RI printing tester (manufactured by Mei Seisakusho) and observing picking on the surface on a 10-point scale (10 being good with no surface picking and 1 being poor with picking occurring on the entire surface).

Example 5 Kaolin (manufactured by Engelhard, USA: trade name UW90)
50 parts, 30 parts of calcium carbonate (manufactured by Okutama Kogyo, trade name Tama Pearl TP222H5), 20 parts of aluminum hydroxide (manufactured by Showa Denko, trade name Hisilite H42), and as a dispersant, 0.3 parts of trade name Aron T40 (manufactured by Toagosei). of water and dispersed in water using a colorless dispersion machine to obtain a concentration of 70%.
A pigment slurry was prepared. Next, 0.2 parts of tributyl phosphate and Pluronic L- (trade name) were added to this as an antifoaming agent.
61 (manufactured by non-electronics) 0.1 part, calcium stearate 10 parts as a mold release agent, water-based urethane resin (as an adhesive)
Manufactured by Mitsui Toatsu Chemical Co., Ltd. (trade name: Orestar UD500) 5 parts,
45 parts of an acrylic emulsion (manufactured by Mitsui Toatsu Chemical Co., Ltd.; trade name: Bonlon 880) was added, and finally water was added to adjust the solid content concentration to 60% to obtain a highly glossy paper coating composition of the present invention. In addition, the viscosity of the obtained coating composition was measured using a BM type viscometer (
The results are shown in Table 2.

Examples 6 to 8 The aqueous urethane resin and acrylic emulsion used in Example 5 were added in the weights shown in Table 2, and the same procedure as in Example 5 was carried out to prepare the highly glossy paper coating composition 3 of the present invention.
Seeds (hereinafter referred to as Examples 6-8 coating compositions) were obtained.

Comparative Example 5 An experiment was conducted in the same manner as in Example 5, except that 0.5 parts of water-based urethane resin and 49.5 parts of acrylic emulsion were used as adhesives, and the results are also listed in Table 2.

Comparative examples 6 and 7 An example of a case where a water-soluble polymer is used in combination is shown below.

As an adhesive, 10 parts of casein dissolved by heating with ammonia water, and the amounts of water-based urethane resin and acrylic emulsion shown in Table 2 were added, and finally water was added to adjust the solid content to the same level of viscosity. 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 also listed in Table 2.

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

Add 25 parts of acrylic emulsion as an adhesive,
A coating composition of Comparative Example 8 was obtained by conducting the same experiment as in Example 5, except that water was added at the end to adjust the solid content concentration to 45%.

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

〔Effect of the invention〕

According to the values in Tables 1 and 2, the highly glossy paper obtained by using the highly glossy paper coating composition according to the example of the present invention has a cast surface with excellent gloss and surface strength. This shows that the coating composition of the present invention is an unprecedented and useful coating composition.

Claims (3)

[Claims] (1) A coating composition containing a pigment and an adhesive as main components, wherein the adhesive is a copolymer of an aliphatic conjugated diolefin monomer, an olefin aromatic monomer, and/or a monoolefin monomer. A coating composition for highly glossy paper comprising 70 to 95% by weight of the solid content of the obtained polymer latex and/or emulsion and 30 to 5% by weight of the solid content of an aqueous urethane resin. (2) A coating composition containing a pigment and an adhesive as main components, the solid content of a polymer emulsion obtained by copolymerizing an olefin aromatic monomer and/or a monoolefin monomer as the adhesive: 70 A coating composition for highly glossy paper comprising ~95% by weight and a solid content of an aqueous urethane resin of 30-5% by weight. (3) Highly glossy paper obtained by coating the composition according to claim 1 or claim 2.