JP3463715B2 - Undercoat agent for release paper - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an undercoat agent for release paper. Specifically, it relates to an undercoat agent for release paper used for release paper obtained by coating a solvent-type silicone resin.

[0002]

2. Description of the Related Art Release paper is widely used in the field of adhesives for labels and seals, and the production amount thereof is increasing year by year. Such release papers were mainly manufactured by a method of directly applying a release agent liquid such as a solvent-type or emulsion-type silicone resin to the backing paper, but since the coating liquid penetrates into the backing paper, release papers have been manufactured in recent years. In doing so, a method of first laminating polyethylene on a mount and applying a solvent-type silicone resin on it is becoming mainstream.

However, due to resource saving and environmental problems, it has become necessary to recycle the paper into recycled paper, and the polyethylene type release paper, which has poor recoverability, is converted to easily recoverable release paper. Is becoming preferred. As a method to make the release paper easily collectable, instead of laminating polyethylene on the mount, apply latex such as polymer emulsion or water-soluble polymer such as polyvinyl alcohol or polyacrylamide to the mount as an undercoating agent. How to do is being studied.

The polymer emulsion used for such an undercoat agent for release paper is generally obtained by emulsion polymerization of various vinyl monomers in the presence of a low molecular weight nonionic emulsifier or anionic emulsifier. Things are being used. However, such conventionally known polymer emulsions have excellent coatability, but since they contain a low molecular weight emulsifier, they lead to a decrease in the strength of the coating film, poor solvent resistance, and toluene of the silicone resin. There is a problem that the toluene solution permeates into the mount when the solution is applied. Further, such a polymer emulsion also has a problem in terms of adhesiveness with a silicone resin. Furthermore, anionic vinyl monomers are usually used in polymer emulsions to assist the emulsifying power of an emulsifier during polymerization and to improve the storage stability of the resulting polymer emulsion. The monomer hinders the fusion of the obtained polymer emulsion particles and reduces the strength of the coating film, which is not preferable in terms of adhesion to the silicone resin.

The undercoat agent for release paper using a water-soluble polymer such as polyvinyl alcohol needs to use a high molecular weight compound (that is, a highly viscous compound) in order to improve solvent resistance. There is a problem of poor stability over time and workability. On the other hand, when the coating is carried out at a low concentration to improve workability, the drying time becomes long and the solution permeates into the mount, which is not preferable.

[0006]

DISCLOSURE OF THE INVENTION The present invention is suitable for an easily recoverable release paper, and even when a solvent type silicone resin is coated on a backing paper, the silicone resin does not penetrate into the paper layer, and It is an object of the present invention to provide an undercoat agent for release paper, which has good adhesion to a silicone resin and excellent coatability.

[0007]

In order to solve the above-mentioned problems, the present inventor has conducted extensive studies on an undercoating agent for release paper used in release paper coated with a solvent-type silicone resin. It has been found that the above-mentioned problems can be solved by using the following specific polymer emulsion. The present invention has been completed based on this new finding.

That is, the present invention is for a release paper containing a polymer emulsion obtained by polymerizing 100 parts by weight of a nonionic vinyl monomer in the presence of 40 to 80 parts by weight of an anionic synthetic polymer protective colloid. Regarding an undercoat agent.

What is an anionic synthetic polymer protective colloid?
It refers to a copolymer composed of an anionic vinyl monomer and a nonionic vinyl monomer.

The anionic vinyl monomer means a vinyl monomer having a carboxylic acid group or a sulfonic acid group, and specific examples of the carboxylic acid group-containing vinyl monomer include (meth) acrylic acid (in the present invention, (meth) acrylic acid). The acid means acrylic acid and / or (meth) acrylic acid, and has the same meaning as (meth) below), itaconic acid, maleic acid, fumaric acid, and alkali metal salts and ammonium salts thereof. Examples of the vinyl monomer having a sulfonic acid group include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and alkali metal salts and ammonium salts thereof. Among these anionic vinyl monomers, (meth) acrylic acid or a salt thereof is preferable as the anionic synthetic polymer protective colloid of the present invention, and methacrylic acid or a salt thereof is particularly preferable. In addition,
The carboxylic acid group or sulfonic acid group of the anionic vinyl monomer may be converted into a salt after producing the anionic synthetic polymer protective colloid.

As the nonionic vinyl monomer, styrene compounds such as styrene, α-methylstyrene and vinyltoluene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, Iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Alkyl (meth) acrylates such as stearyl acrylate; 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, 2-hydroxy-3-
Hydroxyl group-containing (meth) acrylic acid ester such as phenoxypropyl (meth) acrylate and glycerol mono (meth) acrylate; (meth) acrylamide, (meth)
Various known compounds such as acrylonitrile, vinyl acetate, methyl vinyl ether, glycidyl (meth) acrylate, N-methylol (meth) acrylamide, urethane acrylates, diphenyl-2 (meth) acryloyloxyphosphate and the like can be mentioned. As the nonionic vinyl monomer of the anionic synthetic polymer protective colloid of the present invention, among these nonionic vinyl monomers, various (meth) acrylic compounds are preferable, and alkyl (meth) acrylates are particularly preferable.

The amount of the anionic vinyl monomer and the nonionic vinyl monomer used is the anionic vinyl monomer 5
About 0 to 95 parts by weight, nonionic vinyl monomer 5 to 5
It is preferably about 0 parts by weight. More preferably, it is 60 to 80 parts by weight of anionic vinyl monomer and 20 to 40 parts by weight of nonionic vinyl monomer. When the amount of the anionic vinyl monomer used is less than 50 parts by weight, the solvent resistance of the undercoating agent for release paper is insufficient, and when it exceeds 95 parts by weight, anionic synthesis during the production of the polymer emulsion is performed. The emulsifying ability of the polymer protective colloid becomes low, the film-forming property of the obtained polymer emulsion deteriorates, and the solvent resistance cannot be satisfied.

The anionic synthetic polymer protective colloid can be produced by a known aqueous solution polymerization method using the anionic vinyl monomer and the nonionic vinyl monomer in the presence of a radical polymerization initiator.

Aqueous solution polymerization can be carried out in an aqueous solution as well as ethyl alcohol, n-, iso-propyl alcohol,
It can also be carried out in an alcohol such as butyl alcohol or in an aqueous alcohol solution containing these alcohols, or in an aqueous solution containing ethylene glycol, diethylene glycol or the like.

Examples of the radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, water-soluble radical polymerization initiators such as aqueous azo initiators, and the above-mentioned persulfates. Examples thereof include redox-based polymerization initiators in the form of a combination with a reducing agent such as sodium hydrogen sulfite and sodium thiosulfate, and the amount thereof is 100 parts by weight with respect to the total amount of the anionic vinyl monomer and the nonionic vinyl monomer. 0.05 to 5 parts by weight,
It is preferably 0.1 to 3 parts by weight.

The solid content of the reaction system is usually 30 to 5
It is about 0% by weight, preferably 35 to 45% by weight. The pH during the polymerization is usually in the range of about 4-8. The reaction temperature may be in a temperature range that activates the polymerization initiator, and is usually about 40 to 90 ° C., preferably 60.
The reaction time is usually about 30 minutes to 4 hours.

The obtained anionic synthetic polymer protective colloid preferably has a nonvolatile content of about 30 to 45% by weight and a viscosity of about 1000 cps or less (25 ° C.). The weight average molecular weight is about 5,000 to 100,000.

Next, the polymer emulsion used as the undercoat agent for release paper of the present invention will be described. The polymer emulsion of the present invention can be obtained by polymerizing a nonionic vinyl monomer in the presence of the anionic synthetic polymer protective colloid.

As the nonionic vinyl monomer that is polymerized in the presence of the anionic synthetic polymer protective colloid, the same nonionic vinyl monomer that constitutes the anionic synthetic polymer protective colloid can be used.

The amount of the anionic synthetic polymer protective colloid used is 40 to 80 parts by weight, preferably 50 to 70 parts by weight, based on 100 parts by weight of the nonionic vinyl monomer.
Parts by weight. When the amount of the anionic synthetic polymer protective colloid used is less than 40 parts by weight, the solvent resistance cannot be satisfied, and when it exceeds 80 parts by weight, the obtained polymer emulsion has a high viscosity and the coating property is poor. become worse.

As described above, the undercoat agent for release paper of the present invention uses a specific polymer emulsion obtained by polymerizing a nonionic vinyl monomer in the presence of a specific amount of anionic synthetic polymer protective colloid. In the conventional method, the problems of solvent resistance and adhesiveness due to a decrease in the strength of the coating film when a low molecular weight emulsifier is used are improved. Therefore, the nonionic vinyl monomers exemplified above are not particularly limited and may be used alone or in combination of two or more kinds. Among the nonionic vinyl monomers exemplified above, the number of carbon atoms of the alkyl group is not limited. 4 to 8 about 15 to 55 parts by weight of alkyl (meth) acrylate and hydroxyl group-containing (meth) acrylate ester 5 to 5
A mixture prepared to 100 parts by weight of about 30 parts by weight and about 15 to 80 parts by weight of a nonionic vinyl monomer other than these is particularly excellent in solvent resistance and adhesiveness of the obtained undercoat agent for release paper. It is preferable in terms.

Examples of the alkyl (meth) acrylate having 4 to 8 carbon atoms in the alkyl group include n-butyl (meth) acrylate, iso-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. To be The alkyl (meth) acrylate having 4 to 8 carbon atoms in the alkyl group can impart film-forming property to the undercoat agent for release paper, has solvent resistance,
In order to improve the adhesion, it is preferable to use about 15 to 55 parts by weight. It is more preferably 20 to 45 parts by weight.

As the hydroxyl group-containing (meth) acrylic acid ester, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
2-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate,
Examples thereof include glycerol mono (meth) acrylate. Hydroxyl group-containing (meth) acrylic acid ester can improve solvent resistance by introducing hydrophilic group into polymer emulsion in addition to anionic synthetic polymer protective colloid, and has copolymerizability with other nonionic vinyl monomers. Since it is good, it is preferable to use about 5 to 30 parts by weight. It is more preferably 10 to 20 parts by weight.

As the nonionic vinyl monomer other than the alkyl (meth) acrylate having 4 to 8 carbon atoms of the alkyl group and the hydroxyl group-containing (meth) acrylic acid ester,
An alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group or a styrene compound can be preferably used.

The method for producing the polymer emulsion of the present invention may be carried out by a known emulsion polymerization method. For example, a method in which a predetermined reaction vessel is charged with the anionic synthetic polymer protective colloid and water, then a nonionic vinyl monomer is charged and emulsified, a radical polymerization initiator is added, and the mixture is heated under stirring may be used. . As another method, a predetermined reaction container is charged with the anionic synthetic polymer protective colloid and water and heated to a predetermined temperature, and then a nonionic vinyl monomer and a radical polymerization initiator are continuously added for a predetermined time. There is a method of dropping. In addition,
The dropping method of the nonionic vinyl monomer and the radical polymerizable initiator may be either a batch dropping method or a divided dropping method.

In the method for producing a polymer emulsion of the present invention, a small amount of an emulsifier may be added, if necessary, in order to suppress the generation of aggregates in the production process and to stabilize the emulsion after production. It can also be used in combination with a molecular protective colloid. However, the amount to be used is preferably kept to the minimum required amount in consideration of the decrease in strength of the coating film of the undercoat agent for release paper using the obtained polymer emulsion.
Usually, to 100 parts by weight of nonionic vinyl monomer,
It is about 3 parts by weight or less, preferably 1 part by weight or less. The emulsifier is not particularly limited, and various anionic emulsifiers and nonionic emulsifiers can be used. Examples of the anionic emulsifier include long-chain sodium α-olefinsulfonate, alkyldiphenyloxyethylene alkylaryl ether sulfate ester salt, and the like, and examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene block polymer, Polyoxyethylene alkyl phenyl ether etc. can be illustrated.

Examples of the radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, water-soluble radical polymerization initiators such as an aqueous azo initiator, and the above-mentioned persulfates. Examples thereof include redox-based polymerization initiators in the form of a combination with a reducing agent such as sodium hydrogen sulfite and sodium thiosulfate. Usually, the amount of the initiator used is about 0.05 to 5 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the nonionic vinyl monomer.
3 parts by weight is preferable.

The solid content concentration of the reaction system is usually about 30 to 55% by weight, preferably 35 to 45% by weight.
In addition, the pH during polymerization is usually preferably in the range of about 3-9. The reaction temperature may be in the temperature range that activates the polymerization catalyst, and is usually about 40 to 90 ° C, preferably 60 to 90 ° C.
It is 85 ° C., and the reaction time is usually 30 minutes to 4 hours.

During the reaction, a transition metal ion may be added as a polymerization accelerator. Examples of the transition metal ion include copper ion, and the transition metal ion concentration in the reaction system is usually 1.0 × 10 ^{−8 to} 1.0 × 10 ⁻³ mol / mol.
It is recommended to use it so that it is about 1 liter.

Thus, the average particle size is usually 10 to 10.
A polymer emulsion containing fine particles of about 300 nm is obtained. When the polymer emulsion is used as an undercoat agent for release paper, it is preferable to adjust the nonvolatile content to about 30 to 45% by weight and the viscosity to about 1000 cps or less (25 ° C.).

The glass transition temperature of the emulsion polymer thus obtained is 15 to 90 ° C, preferably 25 to 70 ° C. When the glass transition temperature is less than 15 ° C, the sticking property of the coated surface is insufficient and
If the temperature exceeds ℃, the film-forming property of the coating film is not sufficient, which is not preferable in terms of solvent resistance and adhesion.

When the undercoating agent for release paper of the present invention is applied to a base paper, a crosslinking agent such as glyoxal or a water-soluble zirconium compound is used in combination to improve the adhesion to the silicone resin at high temperature and high humidity. It can be further improved. As a coating method of the undercoat agent for release paper, a wire bar, a blade coater,
An air knife coater, a roll coater, or the like can be used, and a known drying device such as an oven or a drum dryer can be used for drying. Further, a calendar process may be performed to adjust the smoothness to a desired level.

[0033]

According to the present invention, even when a solvent-type release agent (for example, a toluene solution of a solvent-type silicone resin) is applied to a mount, the release agent is not absorbed in the paper layer, and It is possible to provide an undercoat agent for release paper, which has excellent coatability and good adhesion with a silicone resin. Furthermore, the release paper obtained by using the undercoating agent for release paper is easy to collect and can contribute to resource saving and environmental problems.

[0034]

EXAMPLES The present invention will be described in more detail below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. In addition,% in each example
Is by weight unless otherwise specified. The glass transition temperature was measured by a differential thermal analyzer.

Production Example 1 (Synthesis of Anionic Synthetic Polymer Protective Colloid) 200 g of isopropyl alcohol and 200 g of water were charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas introducing tube, a monomer dropping funnel and a thermometer. Then, heating was started and the temperature was raised to 80 ° C. under a nitrogen stream. Monomer mixed solution consisting of 210 g of methacrylic acid and 90 g of methyl methacrylate and 100 g of 14% potassium persulfate initiator aqueous solution
Was continuously added over 2 hours. After the addition of the monomer mixture, the reaction was performed for 60 minutes to obtain a resin solution. Isopropyl alcohol was removed from the obtained resin solution by a steam distillation method. Then, water and ammonia water are added to adjust the concentration and pH, and the nonvolatile content is 30%, and the pH is 7.2, 25.
An aqueous resin solution having a viscosity at 85 ° C. of 85 cps was obtained. The water-soluble resin had a weight molecular weight of 35,000.

Production Example 2 (Synthesis of Anionic Synthetic Polymer Protective Colloid) 400 g of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas introducing tube, a monomer dropping funnel and a thermometer, and heated. Starting, the temperature was raised to 80 ° C. under a nitrogen stream. Monomer mixture liquid consisting of 150 g of methacrylic acid and 150 g of methyl methacrylate and 14
% Potassium persulfate initiator aqueous solution 100 g was continuously added over 2 hours. After the addition of the monomer mixture, the reaction was performed for 60 minutes to obtain a resin solution. Isopropyl alcohol was removed from the obtained resin solution by a steam distillation method. Then, water and ammonia water were added to adjust the concentration and pH to obtain a water-soluble resin solution having a nonvolatile content of 30%, a pH of 7.2 and a viscosity of 30 cps at 25 ° C. The weight-average molecular weight of the water-soluble resin was 28,000.

Preparation Example 3 (Synthesis of Anionic Synthetic Polymer Protective Colloid) 400 g of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas introduction tube, a monomer dropping funnel and a thermometer, and heated. Starting, the temperature was raised to 80 ° C. under a nitrogen stream. Monomer mixture consisting of 90 g of methacrylic acid and 210 g of methyl methacrylate and 14%
100 g of an aqueous potassium persulfate initiator solution was continuously added over 2 hours. After the addition of the monomer mixture, the reaction was performed for 60 minutes to obtain a resin solution. Isopropyl alcohol was removed from the obtained resin solution by a steam distillation method. Then by adding water and ammonia water, the concentration and p
H was adjusted to obtain a water-soluble resin solution having a nonvolatile content of 30%, a pH of 7.2, and a viscosity of 30 cps at 25 ° C. The weight-average molecular weight of the water-soluble resin was 28,000.

Example 1 A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube, a monomer dropping funnel and a thermometer was placed in a water-soluble resin solution (anionic) having a nonvolatile content of 30% obtained in Production Example 1. 200 g of synthetic polymer protective colloid and 50 g of water were charged,
While not heating, the temperature was raised to 80 ° C. Next, 100 g of a monomer mixture liquid (weight mixing ratio is 35:45:20 in order) consisting of butyl acrylate, methyl methacrylate and 2-hydroxyethyl methacrylate and 100 g of a 1.8% ammonium persulfate aqueous solution are kept at a constant speed for about 3 hours. Was added and polymerized. After the addition of the monomer mixture, the reaction was performed for 60 minutes to obtain a polymer emulsion. Water was added to the obtained polymer emulsion to adjust the concentration, and
This was a polymer emulsion having a viscosity of 35% at 0%, pH 6.9 and 25 ° C. The glass transition temperature of the obtained emulsion polymer was 60 ° C.

Example 2 In Example 1, instead of the water-soluble resin solution having a nonvolatile content of 30% obtained in Production Example 1 as the anionic synthetic polymer protective colloid, the nonvolatile content 30 obtained in Production Example 2 was used. % Water-soluble resin solution was used to obtain a polymer emulsion in the same manner as in Example 1. Water was added to the obtained polymer emulsion to adjust the concentration, and the nonvolatile content was 30% and pH was adjusted.
A polymer emulsion having a viscosity of 25 cps at 6.8 and 25 ° C was prepared. The glass transition temperature of the obtained emulsion polymer was 56 ° C.

Example 3 In Example 1, as a monomer mixture liquid, 2-ethylhexyl acrylate, styrene, and 2-hydroxyethyl acrylate (weight mixing ratio is 35:45:20 in order).
A polymer emulsion was obtained in the same manner as in Example 1 except that 200 g was used. Water was added to the obtained polymer emulsion to adjust the concentration, and the nonvolatile content was 30% and the pH was 6.
A polymer emulsion having a viscosity of 55 cps at 8 and 25 ° C. was obtained. The glass transition temperature of the obtained emulsion polymer was 42 ° C.

Example 4 In Example 1, as the anionic synthetic polymer protective colloid, the nonvolatile content 30 obtained in Production Example 3 was used instead of the water-soluble resin solution having a nonvolatile content of 30% obtained in Production Example 1. % Water-soluble resin solution was used to obtain a polymer emulsion in the same manner as in Example 1. Water was added to the obtained polymer emulsion to adjust the concentration, and the nonvolatile content was 30% and pH was adjusted.
It was a polymer emulsion having a viscosity of 33 cps at 7.2 and 25 ° C. The glass transition temperature of the obtained emulsion polymer was 52 ° C.

Comparative Example 1 A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas introducing pipe, a monomer dropping funnel and a thermometer was charged with polyoxyethylene alkyl ether sulfate ester (trade name: Hitenol N-08, Daiichi). Kogyo Seiyaku Co., Ltd.) 3 g and water 125
I charged g. Next, 100 g of a monomer liquid mixture (weight mixing ratio is 35:45:20 in order) consisting of 2-ethylhexyl acrylate, methyl methacrylate and 2-hydroxyethyl methacrylate was added and the temperature was raised under a nitrogen stream to 70 ° C. Then, a potassium persulfate initiator (concentration in the system: 6.0 × 10 ⁻³ mol / liter) was added to initiate polymerization. The reaction was carried out for 60 minutes so that the polymerization temperature did not exceed 80 ° C. to obtain a polymer emulsion. The obtained polymer emulsion had a nonvolatile content of 30%, a pH of 8.2, and a viscosity of 33 cps at 25 ° C. The glass transition temperature of the obtained emulsion polymer was 7 ° C.

Comparative Example 2 In Example 1, the nonvolatile content obtained in Production Example 1 was 30%.
A polymer emulsion was obtained in the same manner as in Example 1 except that the amount of the water-soluble resin solution (anionic synthetic polymer protective colloid) used in Example 1 was changed to 100 g. Water was added to the obtained polymer emulsion to adjust the concentration, and
%, PH 7.5, and a polymer emulsion having a viscosity of 20 cps at 25 ° C. The glass transition temperature of the obtained emulsion polymer was 39 ° C.

COMPARATIVE EXAMPLE 3 Except that in Example 1, 200 g of a monomer mixture liquid consisting of acrylic acid, methyl methacrylate and 2-ethylhexyl methacrylate (the weight mixing ratio was 35:45:20 in order) was used as the monomer mixture liquid. Example 1
A polymer emulsion was obtained in the same manner as above. Water was added to the obtained polymer emulsion to adjust the concentration, nonvolatile content 30%, pH 3.2, viscosity at 25 ° C. 100 cps.
Of a polymer emulsion. The glass transition temperature of the obtained emulsion polymer was 116 ° C.

(Performance Evaluation) Examples 1 to 4 and Comparative Examples 1 to 1
3. The polymer emulsion obtained in No. 3, fully saponified polyvinyl alcohol having a degree of polymerization of 500 (trade name PVA105,
After adjusting the coating concentration of Comparative Example 4 manufactured by Kuraray Co., Ltd. to the coating concentration shown in Table 1, P was adjusted so that the solid content was 5 g / m ^2.
PC paper was applied and dried, and then calendered (50 Kg / cm). Using this as a sample, a performance test was conducted according to the following method. The results are shown in Table 1.

(Solvent resistance) Toluene in which a dye was dissolved was applied to the coated surface with a paintbrush, and the presence or absence of strikethrough was observed. ◯: No strikethrough. △: There are strikethroughs in places. X: Many strikethroughs.

(Silicone adhesion) 1% of a curing catalyst (CAT-PL-8, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to a silicone resin (KS776A, manufactured by Shin-Etsu Chemical Co., Ltd.) diluted to a concentration of 5% with toluene. After coating the added amount (based on the solid content of KS766A) so that the solid content deposition amount becomes 1 g / m ² , it is first dried at 70 ° C. for 30 seconds and then dried and cured at 140 ° C. for 1 minute. It was Then 20
After standing for 1 day under conditions of ℃ and humidity of 65% (condition 1)
After being left for 1 week under each condition of 50 ° C. and humidity of 90% (condition 2), the coated surface was rubbed with a finger and the peeled state of the silicone was observed. ◯: Does not peel. Δ: A little peeled off. X: Completely peeled.

[0048]

[Table 1]

In Comparative Example 4, the coating density is 1 which is half of that in Example.
Despite 0%, unevenness occurred during coating.

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-6-145612 (JP, A) JP-A-3-281675 (JP, A) JP-A-63-120770 (JP, A) JP-A-62- 70410 (JP, A) JP 2-308881 (JP, A) JP 4-209682 (JP, A) JP 6-107713 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 133/00-133/26 C09D 5/00 C09J 7/02-7/04 D21H 27/00

Claims (4)

(57) [Claims] 1. Anionic synthetic polymer protective colloid 40.
In the presence of -80 parts by weight of nonionic vinyl monomer 1
An undercoat agent for release paper, which comprises a polymer emulsion obtained by polymerizing 100 parts by weight. 2. An anionic synthetic polymer protective colloid,
The undercoat for release paper according to claim 1, which is a copolymer of 50 to 95 parts by weight of (meth) acrylic acid and / or a salt thereof and 5 to 50 parts by weight of a (meth) acrylic nonionic vinyl monomer. Agent. 3. 100 parts by weight of a nonionic vinyl monomer, 15 to 55 parts by weight of an alkyl (meth) acrylate having 4 to 8 carbon atoms, 5 to 30 parts by weight of a hydroxyl group-containing (meth) acrylate ester, and The undercoat agent for release paper according to claim 1, which is a mixture of 15 to 80 parts by weight of a nonionic vinyl monomer other than the above. 4. The undercoat agent for release paper according to claim 1, wherein the glass transition temperature of the emulsion polymer is 15 to 90 ° C.