JPH0248680B2 - KAMIKOOTEINGUYOSUIYOSEIJUSHISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a water-soluble resin composition for coating paper such as printing paper. [Prior art] It is well known that printing paper is coated with resin paint in order to protect the printing surface and give gloss and waterproof properties to the printing paper. There are several known methods, including a method of applying hot press processing after coating. Traditionally, paints for paper coating include:
Copolymers of vinyl unsaturated monomers such as vinyl chloride, vinyl acetate, and (meth)acrylic acid esters, and styrene aromatic monovinyl monomers are mixed with aromatic solvents such as benzene, toluene, and xylene, acetone, methyl ethyl ketone, and methyl. Ketone solvents such as isobutyl ketone and cyclohexane, ethylene glycol monomethyl ether,
Ether alcohols such as ethylene glycol monoethyl ether and mixtures of their esters are widely used. However, as mentioned above, those using organic solvents as solvents have had serious problems in terms of safety and health due to the flammability and toxicity of these organic solvents. Therefore, there is a demand in the industry for the development of an excellent water-based paper coating paint that has performance comparable to the conventional solvent-based paints mentioned above.
No. 066597 reports a water-soluble resin composition for paper coating, which is obtained by neutralizing the carboxyl groups of a vinyl monomer copolymer with a volatile base. [Problems to be solved by the invention] However, conventional water-based gloss paints dry more slowly than solvent-based paints, and the physical properties of the paint film are also inferior. releasability,
Improvements were needed in terms of coating film properties such as blocking resistance and water resistance. Incidentally, the brittleness and mold releasability of the coating film are physical properties required when performing hot press processing using a mirror-finished plate. In water-soluble resin compositions for paper coating made by neutralizing the carboxyl groups of a vinyl monomer copolymer as described above with a volatile base, carboxyl groups are added to the monomer composition of the copolymer in order to improve its water dilutability. Although it is necessary to blend a large amount of the group-containing monomer, on the other hand, if the blending ratio of the carboxyl group-containing monomer becomes high, it is inevitable that the blistering resistance and water resistance of the coating film will decrease. Therefore,
In the above-mentioned type of water-soluble resin composition for paper coating, the subject of research is to satisfactorily solve the conflicting physical property problems of the water solubility and water dilutability of the resin and the water resistance and blistering property of the coating film. Solving this problem will lead to expanded applications in hot press processing. The purpose of the present invention is to solve the problems of the prior art as described above, and to improve gloss, blistering properties, mold releasability, blocking resistance, water resistance, etc. while maintaining good water solubility and water dilutability. An object of the present invention is to provide a water-soluble resin composition for paper coating that provides improved coating film properties. [Technical means for solving the problem] In order to achieve the above object, in the present invention, (A) general formula (In the formula, X and Y are hydrogen or methyl group, n is 1
(an integer of ~10) 4-10% by weight (B) General formula (In the formula, R ₁ is hydrogen or a methyl group, R ₂ is a methyl group or an ethyl group, and n is an integer of 4 to 25.) 1 to 7.5% by weight (C) Methyl methacrylate 40-90% by weight (D) α, β- containing acrylic acid and methacrylic acid
Unsaturated carboxylic acid 5-12.5% by weight (E) Other radically polymerizable vinyl monomers Obtained by radical polymerization of a monomer mixture consisting of 30% by weight or less in an alcohol or a mixed solvent mainly composed of alcohols. A water-soluble resin composition for paper coating is selected by neutralizing the carboxyl groups of the copolymer obtained by neutralizing the carboxyl groups with a volatile base. [Operation of the invention] In the above, component (A), that is, the general formula (In the formula, X and Y are hydrogen or methyl group, n is 1-
Monomers with the structure shown by It is necessary to impart properties such as durability, water resistance, and gloss, and one type thereof can be used alone or two or more types can be used in combination. If the blending amount of component (A) exceeds 10% by weight, and if a large amount of component (D) such as acrylic acid and methacrylic acid is blended, the solution will undergo intramolecular crosslinking, resulting in a gelation phenomenon, resulting in paint failure. It cannot be used as an undiluted solution.
Furthermore, if a small amount of component (D) is blended in the above, gelation does not occur, but the hydrophilicity of component (A) is no longer blocked by crosslinking, and water resistance deteriorates. On the other hand, if the blending amount of component (A) is less than 4% by weight, if a small amount of component (D) is blended, the hydrophilicity will decrease, water dilutability and gloss will decrease, and the component
If a large amount of (D) is blended, the crushability and mold release properties will decrease. Next, component (B), that is, the general formula (In the formula, R ₁ is hydrogen or a methyl group, R ₂ is a methyl group or an ethyl group, and n is an integer from 4 to 25.) It is necessary to impart anti-whitening properties and anti-glare shrinkage properties to the film, and one or both of them may be used alone or in combination.
More than one species can be used in combination. In addition,
If the amount of this component (B) exceeds 7.5% by weight, the water resistance and blocking resistance of the coating film will decrease, and if it is less than 1% by weight, sufficient anti-whitening and anti-glare shrinkage properties will be obtained. I can't do it. In addition, component (C), methyl methacrylate, is necessary to impart gloss, blocking resistance, and mold release properties to the coating film, and if the amount is less than 40% by weight, the softening point of the resin will be low. This results in poor mold release during hot pressing, and the coating film lacks blocking resistance and gloss. On the other hand, its component (C)
If more than 90% by weight is added, the water dilutability of the resin and the adhesion of the coating film will decrease. Furthermore, component (D), an α,β-unsaturated carboxylic acid containing acrylic acid and methacrylic acid, is necessary to make the resin water-soluble and provide adhesion to the coating film, and is necessary to obtain the desired coating film. For this purpose, it is necessary to use acrylic acid and methacrylic acid in combination, but if necessary, a part of them may be replaced with itaconic acid or other components. If the amount of component (D) is less than 5% by weight, the water dilutability of the resin and the adhesion of the paint film will be poor, and if it exceeds 12.5% by weight, the paint film will have poor blistering and water resistance. Sexuality becomes poor. In addition, the other radically polymerizable vinyl monomers of component (E) provide adhesion to the coating film, scratch resistance,
It is used as appropriate to impart water resistance, etc.
If the blending amount exceeds 30% by weight, blocking resistance, mold releasability and crumbling properties will be poor. Examples of such component (E) include alkyl (meth)acrylates such as ethyl (meth)acrylate, butyl (meth)acrylate, and propyl (meth)acrylate, and non-containing compounds such as (meth)acrylonitrile. Examples include saturated nitriles, unsaturated amides such as (meth)acrylamide, styrene, and vinyltoluene. The copolymers consisting of the above various monomer components have carboxyl groups such as ammonia, dimethylethanolamine, morpholine, methylmorpholine, 2
It may be neutralized with a volatile base such as -amino-2-methylpropanol to make it water-soluble and diluted with water, preferably to a solid content of about 20 to 30% by weight. In addition, during its preparation, various additives and auxiliaries may be added as necessary. For example, as is known, nonionic or anionic surfactants and silicone oil may be added to facilitate mold release during hot pressing, and to impart slipperiness, abrasion resistance, and blocking resistance. For this purpose, nonionic, anionic surfactants, waxes, etc. can also be added. The water-soluble resin composition for paper coating according to the present invention is coated on printing paper using a roll coater, gravure cylinder, etc., dried using an infrared heater, hot air dryer, etc., and then hot-pressed. [Examples] Next, the present invention will be specifically explained based on Examples, but the present invention is not limited to these Examples. Note that parts and percentages in the following Examples and Comparative Examples are based on weight unless otherwise specified. Example 1 <Monomer mixture> 2-hydroxypropyl methacrylate 20 parts Methoxypolyethylene glycol methacrylate (n=6) 5 parts Methyl methacrylate 150 parts Acrylic acid 8 parts Methacrylic acid 15 parts Itaconic acid 2 parts Azobisisobutyro 3 parts nitrile 1 part dodecyl mercaptan Stirrer, thermometer, reflux condenser with dropping funnel,
150 parts of isopropyl alcohol was charged into a polymerization apparatus equipped with a nitrogen gas introduction tube, nitrogen gas was aerated, and the mixture was heated to 80°C with stirring, into which a monomer mixture with the above composition was added dropwise over 3 hours. Add 0.5 parts of azobisisobutyronitrile dispersed in 5 parts of isopropyl alcohol three times every hour at the same temperature. Polymerization was completed at a reaction temperature of 80° C. and a total reaction time of 8 hours. Then, after cooling, 19.3 parts of 25% ammonia water was dissolved in 30.7 parts of water, and the neutralization rate was
A water-soluble acrylic resin composition with a solid content of 90% by mole and 40% was obtained. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. The paint solution was applied to offset printing test paper using a roll coater equipped with an infrared heater, and then applied using a Matsumoto endless press at a press temperature of 110℃ and a press pressure of 250℃.
When hot pressing was carried out under the conditions of Kg/cm ² and press speed of 20 m/min, the mold releasability during hot pressing was good, and the resulting processed paper had excellent coating film gloss, blistering, adhesion, and It had excellent blocking resistance and water resistance. Comparative Example 1 <Monomer mixture> Methyl methacrylate 166 parts Ethyl methacrylate 24 parts Acrylic acid 4 parts Methacrylic acid 6 parts Azobisisobutyronitrile 3 parts Dodecyl mercaptan 0.5 parts Isopropyl alcohol in the same polymerization apparatus as Example 1 A monomer mixture having the above composition was added dropwise to the mixture, which was heated to 80°C while bubbling with nitrogen gas and stirring. Polymerization was carried out in the same manner as in Example 1, followed by cooling. 25% ammonia water 8.5
1 part was dissolved in 41.5 parts of water and added to obtain a water-soluble acrylic resin composition with a neutralization rate of 100 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it became cloudy and insolubilized and could not be made into a paint. Therefore, the above water-soluble acrylic resin composition with a solid content of 40% was mixed with isopropyl alcohol to give a solid content of 25%.
When diluted to make a coating solution and applied to offset printing test paper under the same conditions as in Example 1 and hot-pressed, the mold release properties during hot-pressing were good, but the resulting processed paper The coating film had poor gloss and adhesion and was unusable. Comparative Example 2 <Monomer mixture> Methyl methacrylate 175 parts Acrylic acid 8 parts Methacrylic acid 15 parts Itaconic acid 2 parts Azobisisobutyronitrile 3 parts Dodecyl mercaptan 1 part Isopropyl alcohol 150 parts was added to the same polymerization apparatus as in Example 1. A monomer mixture having the above composition was added dropwise to the mixture, which was heated to 80°C while bubbling with nitrogen gas and stirring. Polymerization was carried out in the same manner as in Example 1, and then cooled. 25% ammonia water 19.3
1 part was dissolved in 30.7 parts of water and added to obtain a water-soluble acrylic resin composition with a neutralization rate of 90 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. When the coating solution was applied to offset printing test paper and hot-pressed under the same conditions as in Example 1, the mold releasability during hot-pressing was good, but the resulting processed paper did not show the coating film. Bulking resistance, blocking resistance and water resistance are poor.
It was unusable. Comparative Example 3 <Monomer mixture> 2-Hydroxypropyl methacrylate 7 parts Methoxypolyethylene glycol methacrylate (n=9) 1 part Methyl methacrylate 167 parts Acrylic acid 8 parts Methacrylic acid 15 parts Itaconic acid 2 parts Azobisisobutyro Nitrile 3 parts Dodecyl mercaptan 1 part 150 parts of isopropyl alcohol was charged into the same polymerization apparatus as in Example 1, nitrogen gas was aerated, and the monomer mixture having the above composition was added dropwise to the mixture heated to 80°C with stirring. Polymerization was carried out in the same manner as in Example 1, and then cooled and 19.3% 25% ammonia water was added.
1 part was dissolved in 30.7 parts of water and added to obtain a water-soluble acrylic resin composition with a neutralization rate of 90 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. When the coating solution was applied to offset printing test paper and hot-pressed under the same conditions as in Example 1, the mold releasability during hot-pressing was good, but the resulting processed paper did not show the coating film. Poor blistering resistance, blocking resistance, and water resistance;
It was unusable. Example 2 <Monomer mixture> 2-hydroxyethyl methacrylate 9 parts Methoxypolyethylene glycol methacrylate (n=6) 3 parts Methyl methacrylate 140 parts Butyl methacrylate 18 parts Ethyl acrylate 10 parts Acrylic acid 6 parts Methacrylic acid 14 1 part azobisisobutyronitrile 3 parts 150 parts of isopropyl alcohol was placed in the same polymerization apparatus as in Example 1, and the monomer mixture having the above composition was heated to 80°C while bubbling nitrogen gas and stirring. Polymerization was carried out in the same manner as in Example 1, followed by cooling and adding 25% ammonia water (16.7 cm).
1 part was dissolved in 33.3 parts of water and added to obtain a water-soluble acrylic resin composition with a neutralization rate of 100 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. When the coating solution was applied to offset printing test paper under the same conditions as in Example 1 and hot-pressed, the mold releasability during hot-pressing was good, and the resulting processed paper had a glossy coating, It had excellent blistering properties, adhesion, blocking resistance, and water resistance. Example 3 <Monomer mixture> 2-hydroxyethyl methacrylate 6 parts 2-hydroxypropyl acrylate 6 parts Ethoxypolyethylene glycol methacrylate (n=6) 4 parts Methyl methacrylate 146 parts Isobutyl methacrylate 12 parts Butyl acrylate 4 parts acrylic acid 7 parts methacrylic acid 13 parts azobisisobutyronitrile 3 parts dodecyl mercaptan 0.5 parts In a polymerization apparatus similar to Example 1, 100 parts of isopropyl alcohol, 50 parts of ethyl alcohol, and 1 part of the monomer mixture having the above composition were added. The remaining 2/3 of the monomer mixture having the above composition was added dropwise to the mixture, which was heated to 80°C while aerating nitrogen gas and stirring, and polymerization was carried out in the same manner as in Example 1. After cooling, 15.2 parts of 25% ammonia water dissolved in 34.8 parts of water was added to obtain a water-soluble acrylic resin composition with a neutralization rate of 90 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. When the coating solution was applied to offset printing test paper under the same conditions as in Example 1 and hot-pressed, the mold releasability during hot-pressing was good, and the resulting processed paper had a glossy coating, It had excellent blistering properties, adhesion, blocking resistance, and water resistance. Example 4 <Monomer mixture> 2-hydroxyethyl methacrylate 8 parts Polypropylene glycol methacrylate (n=
6) 2 parts ethoxy polyethylene glycol methacrylate (n = 4) 5 parts methyl methacrylate 155 parts isobutyl methacrylate 15 parts acrylic acid 5 parts methacrylic acid 10 parts azobisisobutyronitrile 3 parts dodecyl mercaptan 1 part Same as Example 1 Example 1 was prepared by charging 130 parts of isopropyl alcohol and 20 parts of ethylene glycol monobutyl ether into a polymerization apparatus, bubbling nitrogen gas, and heating the mixture to 80°C with stirring. Polymerization was carried out in the same manner as above, and then cooled and 10.1 parts of 25% ammonia water dissolved in 39.9 parts of water was added to give a neutralization rate of 80 mol%.
A water-soluble acrylic resin composition with a solid content of 40% was obtained.
Next, the water-soluble acrylic resin composition is reduced to a solid content.
When diluted with water to 25%, it was easily dissolved and a clear paint solution was obtained. When the coating solution was applied to offset printing test paper under the same conditions as in Example 1 and hot-pressed, the mold releasability during hot-pressing was good, and the resulting processed paper had a glossy coating, It had excellent blistering properties, adhesion, blocking resistance, and water resistance. Example 5 <Monomer mixture> 2-hydroxyethyl methacrylate 10 parts Polyethylene glycol methacrylate (n=
9) 2 parts methoxypolyethylene glycol methacrylate (n=9) 3 parts methyl methacrylate 155 parts styrene 5 parts lauryl methacrylate 10 parts acrylic acid 4 parts methacrylic acid 11 parts azobisisobutyronitrile 3 parts dodecyl mercaptan 1 part Examples 150 parts of isopropyl alcohol was charged into the same polymerization apparatus as in Example 1, and the monomer mixture having the above composition was added dropwise to the mixture, which was heated to 80°C while aerating with nitrogen gas, and the same operation as in Example 1 was carried out. Polymerization is carried out with 25% ammonia water after cooling.
1 part was dissolved in 38.8 parts of water and added to obtain a water-soluble acrylic resin composition with a neutralization rate of 90 mol% and a solid content of 40%. Next, when the water-soluble acrylic resin composition was diluted with water to a solid content of 25%, it was easily dissolved and a transparent coating solution was obtained. When the coating solution was applied to offset printing test paper under the same conditions as in Example 1 and hot-pressed, the releasability during hot-pressing was good, and the resulting processed paper had a glossy coating, It had excellent blistering properties, adhesion, blocking resistance, and water resistance. Comparison of physical properties of water-soluble resin compositions Table 1 shows the results of comparing the physical properties of the water-soluble resin compositions for paper coating according to Examples 1 to 5 and Comparative Examples 1 to 3 for each item.

【table】

〔Effect of the invention〕

As described above, the water-soluble resin composition for paper coating according to the present invention has good water solubility and water dilutability required for coating, and also has gloss and
It is possible to provide a coating film with excellent physical properties in terms of blistering properties, mold release properties, blocking resistance, water resistance, etc.

Claims (1)

[Claims] 1 (A) General formula (In the formula, X and Y are hydrogen or methyl group, n is 1
(an integer of ~10) 4-10% by weight (B) General formula (In the formula, R ₁ is hydrogen or a methyl group, R ₂ is a methyl group or an ethyl group, and n is an integer of 4 to 25.) 1 to 7.5% by weight (C) Methyl methacrylate 40-90% by weight (D) α, β- containing acrylic acid and methacrylic acid
Unsaturated carboxylic acid 5-12.5% by weight (E) Other radically polymerizable vinyl monomers Obtained by radical polymerization of a monomer mixture consisting of 30% by weight or less in an alcohol or a mixed solvent mainly composed of alcohols. A water-soluble resin composition for paper coating, which is obtained by neutralizing the carboxyl groups of a copolymer obtained by neutralizing the carboxyl groups with a volatile base.