JPH10273618A - Undercoating agent for release paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an undercoating film for release paper, having various performances such as barrier properties or adhesion to a silicone resin required for an undercoating agent for the release paper, good in stability when mixed with a pigment such as a clay and capable of carrying out the high- concentration coating. SOLUTION: This undercoating agent for release paper comprises a copolymer emulsion, prepared by copolymerizing a monomer mixture comprising (A) a monomer having one (meth)allyl group as a carbon-carbon double bond and/or (B) N-(meth)acrylamides represented by the general formula (1):CH2 =C(R<1> )- CONR<2> (R<3> ) (R<1> denotes hydrogen atom or methyl group; R<2> denotes hydrogen atom or a 1-4C straight-chain or branched chain alkyl group; R<3> denotes a 1-4C straight-chain or branched alkyl group) and (C) a nonionic vinyl monomer except the component B in the presence of an emulsifying agent and having -60 to +50 deg.C glass transition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an undercoat agent for release paper. More specifically, the present invention relates to an undercoat agent for release paper that can be used stably at a high concentration even when a pigment is mixed.

[0002]

2. Description of the Related Art In the production of release paper used in the field relating to adhesives for labels and seals, the mainstream method is to first laminate polyethylene on a base paper and then apply a release solution such as a silicone resin on the base paper. It is. However, due to resource and environmental issues, the need to recycle paper into recycled paper has arisen, and it is desired to convert the polyethylene-based release paper with poor recoverability into easily recoverable release paper. It has become.

As a method for making the release paper easily recoverable, a method of applying an undercoat agent to the base paper instead of laminating polyethylene on the base paper has been proposed. As the undercoat agent, emulsions such as SBR and acrylic emulsion, various water-soluble polymers such as polyvinyl alcohol and polyacrylamide, and pigments such as inorganic clay are used.

[0004] Among the undercoat agents, polyvinyl alcohol is currently the mainstream in place of polyethylene due to its low cost. However, at present, the polyvinyl alcohol aqueous solution has many problems such that high-concentration coating cannot be performed due to high viscosity and heat resistance and the like.

[0005] Clay has the feature that it can be coated at a higher concentration than water-soluble polymers such as polyvinyl alcohol, and is generally less expensive than emulsions such as acrylic emulsions and has a lower coating amount. Has recently attracted particular attention because it can be increased. The undercoat agent using clay is usually used in combination with polyvinyl alcohol, starch or the like in order to reinforce the solvent resistance or adjust the viscosity of the coating solution. However, the undercoating agent using clay has a problem that the coating film is hard and brittle, so that the coating film surface cracks or powder is generated when cutting or processing release paper, thereby deteriorating the working environment and operability. . For this reason, various emulsions or water-soluble polymers are often used in combination with clay-based undercoat agents for the purpose of imparting flexibility.

However, emulsions and the like generally used as an undercoat agent use acrylic acid monomers such as acrylic acid and methacrylic acid as a part of the polymerization component for the purpose of imparting solvent resistance. When mixing the emulsion and the clay, the carboxylic acid is often adsorbed to the positive charge on the surface of the clay to form an aggregate, which makes it difficult to stably and uniformly mix the clay. Therefore, when preparing an undercoat agent obtained by mixing an emulsion or the like with clay, p
In general, a method of adjusting the H or changing the charge state of the clay surface using an acid salt such as a phosphate to enhance the mixing stability with a carboxylic acid is used. Stability cannot be sufficiently enhanced. Particularly when the amount of carboxylic acid in the emulsions is large, there is almost no effect.

On the other hand, emulsions containing no carboxylic acid are excellent in mixing stability with clay, but are inferior in solvent resistance because there is no carboxylic acid serving as a hydrophilic group. Also, polyacrylamide is not suitable for use for the purpose of imparting flexibility by mixing with clay because the glass transition temperature is too high, and when used alone as an undercoat agent, it causes curing inhibition of silicone. In some cases, the barrier properties and adhesion to the silicone resin are insufficient. Also, when mixed with clay at a high concentration, it becomes high viscosity,
There is a problem similar to polyvinyl alcohol.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides various properties such as barrier properties and adhesion to silicone resin required for an undercoat agent for release paper, and when mixed with a pigment such as clay. Another object of the present invention is to provide an undercoat agent for release paper which has good stability and is capable of high-concentration coating.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a release paper containing a copolymer emulsion containing a monomer mixture having a specific composition shown below is obtained. It has been found that the undercoat agent can solve all of the above problems. The present invention has been completed based on such new findings.

That is, the present invention relates to (A) a monomer having one (meth) allyl group as a carbon-carbon double bond and / or (B) a general formula (1): CH ₂ ＣC (R ¹ )
—CONR ² (R ³ ) (wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ is a 1 to 4 carbon atom. N-substituted (meth) acrylamides represented by a straight-chain or branched-chain alkyl group);
The present invention relates to an undercoat agent for release paper containing a copolymer emulsion having a glass transition temperature of -60 to 50 ° C, which is obtained by copolymerizing a monomer mixture comprising a nonionic vinyl monomer excluding components in the presence of an emulsifier. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a monomer constituting a copolymer emulsion used as an undercoat agent for release paper includes (A) a monomer having one (meth) allyl group as a carbon-carbon double bond. And / or (B) the general formula (1): CH ₂ ＣC (R ¹ ) -CONR
² (R ³ ) (wherein, R ¹ is a hydrogen atom or a methyl group;
² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ represents a linear or branched alkyl group having 1 to 4 carbon atoms). Acrylamides and a monomer mixture of (C) a nonionic vinyl monomer excluding the component (B) are used.

(A) As a carbon-carbon double bond, (meth)
A monomer having one allyl group is defined as (meth)
A monomer having only one allyl group and having no carbon-carbon double bond other than the (meth) allyl group. In addition, when there are two or more (meth) allyl groups in the molecule, it is not preferable because gelation occurs and the molecular weight distribution becomes wide. The same applies to a case having another carbon-carbon double bond different from a (meth) allyl group, for example, an acryloyl group. Examples of such a monomer having one (meth) allyl group as a (A) carbon-carbon double bond include:
At least one selected from (meth) allylsulfonic acid, (meth) allylcarboxylic acid and salts thereof and (meth) allyl alcohol can be used. These (A)
Among the components, (meth) allyl sulfonic acid or a salt thereof is preferable in that the obtained copolymer emulsion has a high concentration and a low viscosity, and methallyl sulfonic acid or a salt thereof is more preferable in terms of monomer stability. Examples of the salt include an alkali metal salt such as a sodium salt and a potassium salt, an ammonium salt, and the like.

(B) General formula (1): CH ₂ ＣC (R ¹ )
—CONR ² (R ³ ) (wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ is a 1 to 4 carbon atom. A linear or branched alkyl group having 1 to 4 carbon atoms at R ² or R ³ in an N-substituted (meth) acrylamide represented by a linear or branched alkyl group) Examples include a methyl group, an ethyl group, an isopropyl group, and a t-butyl group. As specific examples of the component (B),
N, N-dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N
-Isopropyl (meth) acrylamide and Nt-
Butyl (meth) acrylamide; and at least one selected from these can be used. Among these components (B), dimethylacrylamide is preferred in view of copolymerizability and chain transfer.

The above components (A) and (B) are both intended to introduce many branched structures into the obtained copolymer emulsion by utilizing the chain transfer properties of the components. By using this technique, a branched polymer without gelation can be obtained, and a high-concentration, low-viscosity copolymer emulsion can be obtained. Even if a generally known chain transfer agent such as isopropyl alcohol is used instead of the components (A) and (B), a copolymer emulsion having a reduced viscosity cannot be obtained. When a crosslinkable vinyl monomer (having at least two double bonds) is used, the copolymer emulsion is apt to gel, and it is difficult to produce it at a high concentration.

(C) As the nonionic vinyl monomer excluding the component (B), various known nonionic vinyl monomers can be used without particular limitation. However, the barrier properties required for an undercoat agent for release paper and the adhesion to a silicone resin are sufficient. (A) alkyl (meth) acrylates having 4 to 8 carbon atoms in the alkyl group from 30 to 85 in view of various properties such as properties and mixing stability with pigments such as clay.
Weight percent, (b) about 5 to 60 weight percent of a hydroxyl group-containing (meth) acrylate, and (c) the (a) and (b)
It is preferable to use a nonionic vinyl monomer composed of about 10 to 65% by weight.

(A) 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. And the like.
(A) Alkyl (meth) acrylate having 4 to 8 carbon atoms in the alkyl group can impart flexibility and film forming property to the undercoat agent for release paper, and can improve the yield of silicone on the paper surface. Its use ratio is about 30 to 85% by weight of the component (C). The lower limit of the use ratio is 40% by weight,
The upper limit is more preferably 80% by weight. 30 usage
When the amount is less than the weight percentage, the glass transition temperature of the copolymer emulsion tends to increase, and the flexibility of the coating film tends to be insufficient. On the other hand, when the content exceeds 85% by weight, the flexibility and tackiness of the coating film tend to be increased, and the solvent resistance generally tends to be reduced.

The (b) hydroxyl group-containing (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and polyethylene glycol mono ( Meth) acrylate, 2-
Examples thereof include hydroxy-3-phenoxypropyl (meth) acrylate and glycerol mono (meth) acrylate. (B) The hydroxyl group-containing (meth) acrylic ester can improve the water dispersibility at the time of polymerization by introducing a hydrophilic group into the copolymer emulsion, and can improve the adhesion by bonding between the hydroxyl group and the silicone polymer. Its use ratio is 5 to 60% by weight of the component (C). The upper limit of the use ratio is more preferably 40% by weight. If the amount is less than 5% by weight, the adhesion to the silicone applied to the coating film surface tends to decrease. On the other hand, if it exceeds 60% by weight, the glass transition temperature of the copolymer tends to increase, and the flexibility of the coating film tends to be insufficient. In addition, the viscosity of the copolymer emulsion tends to be high, the workability is reduced, and the flexibility and adhesiveness of the coating film are likely to be strong.

(C) Nonionic vinyl monomers other than the above (a) and (b) include styrene compounds such as styrene, α-methylstyrene and vinyltoluene;
Alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and stearyl (meth) acrylate; ) Acrylamide, (meth) acrylonitrile, vinyl acetate, methyl vinyl ether, glycidyl (meth) acrylate,
Various known compounds such as N-methylol (meth) acrylamide, urethane acrylates, diphenyl-2 (meth) acryloyloxyphosphate and the like can be mentioned. The usage ratio of the nonionic vinyl monomer (c) is 10 to 65% by weight of the component (C). The lower limit of the use ratio is more preferably 20% by weight, and the upper limit is more preferably 50% by weight. If the amount used exceeds 60% by weight, the glass transition temperature of the copolymer emulsion tends to increase, the flexibility of the coating film tends to be insufficient, and the viscosity of the copolymer emulsion tends to increase. Is reduced.

In the present invention, among the nonionic vinyl monomers (c), acrylamide, alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group, and styrene compounds can be preferably used. Acrylamide is a water-soluble monomer, which is preferable in that it has a large effect on the solvent resistance of the coating film. It is preferable in that it has good effects on glass transition temperature, coating properties, and solvent resistance of the coating film. Particularly, in order to impart solvent resistance, it is preferable to use acrylamide in an amount of 10 to 40% by weight of the component (C).

In the present invention, the amount of each component of the monomer mixture comprising the components (A), (B) and (C) determines the performance of the obtained copolymer emulsion as an undercoat agent for release paper. Make a decision with due consideration. Usually, the amount of component (A) and / or component (B) used is
It is about 0.01 to 10 parts with respect to 100 parts of the component (C). The upper limit of the amount of component (A) and / or component (B) used is preferably 5 parts by weight, more preferably 3 parts by weight.
Parts by weight. The lower limit is preferably 0.05
Parts by weight, more preferably 0.1 parts by weight. In addition,
When the components (A) and (B) are used in combination, the total weight is within the above range. The amount of the component (A) and / or the component (B) used is based on 100 parts of the component (C).
If it exceeds about 10 parts, it is difficult to obtain sufficient barrier properties as an undercoat agent for release paper, and it is difficult to obtain a stable copolymer emulsion when mixed with clay or the like.

The copolymer emulsion of the present invention can be prepared by a known emulsion polymerization method using the component (A) and / or
Alternatively, it can be obtained by copolymerizing a monomer mixture comprising the component (B) and the component (C) in the presence of an emulsifier. For example, after charging water in a predetermined reaction vessel, then charging the monomer mixture and the emulsifier, and stirring,
The method can be carried out by adding a radical polymerization initiator and heating under stirring. As another method, water is charged into a predetermined reaction vessel, heated to a predetermined temperature, and then the monomer mixture and an emulsifier are mixed in water to form a pre-emulsified aqueous solution. There is a method of dropping continuously after a predetermined time is required.
The method of dropping the monomer mixture or the radical polymerizable initiator may be any of batch dropping and split dropping.

The emulsifier is not particularly limited, and examples thereof include anionic surfactants such as oleate, laurylate, alkylbenzene sulfonate, dialkyl sulfosuccinate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl. Nonionic surfactants such as ether, polyoxyethylene phenyl ether and polyoxyethylene alkyl allyl ether can be exemplified. In addition, a relatively low-molecular polymer compound having emulsifying and dispersing ability, for example, polyvinyl alcohol, and a modified product thereof, polyacrylamide, a polyethylene glycol derivative, a neutralized product of a polycarboxylic acid copolymer, casein, etc. alone or as described above. It can be used in combination with an emulsifier. Further, a water-soluble acrylic copolymer can be used as an emulsifier. The amount of the emulsifier used is generally and preferably about 0.5 to 5 parts by weight based on 100 parts by weight of the monomer mixture. If the amount is less than 0.5 part by weight, a stable copolymer emulsion is hardly formed, and the generation of aggregates tends to increase. On the other hand, when the amount exceeds 5 parts by weight, the viscosity of the copolymer emulsion becomes high and it may be difficult to efficiently synthesize a high-concentration emulsion. Further, in the case of a low-molecular-weight emulsifier, the adhesion of silicone is reduced. It can also be the cause. However, the amount of the above-mentioned emulsifier is not necessarily limited to this range. For example, when it is considered that the adhesiveness of silicone is not adversely affected as in the case of a polymer emulsifier, the use of 5 parts by weight or more is also possible. is there. When a polymer compound containing a large amount of carboxylic acid is used as an emulsifier, care must be taken because aggregates may be generated when mixed with clay depending on the amount used.

Examples of the radical polymerization initiator include water-soluble radical polymerization initiators such as persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, aqueous azo initiators, and the like. Redox polymerization initiators in the form of a combination with a reducing agent such as sodium hydrogen sulfite, sodium thiosulfate and the like can be mentioned. The amount of the initiator used is not particularly limited, but is usually about 0.5 to 5 parts by weight based on 100 parts by weight of the monomer mixture.

The solid concentration of the reaction system is usually about 20 to 70% by weight. If the viscosity is low, the solid content concentration is usually preferably higher. In addition, the pH at the time of polymerization is usually preferably in the range of about 2 to 9. The reaction temperature may be within a temperature range for activating the radical polymerization initiator, and is usually 40 to 9
The lower limit is about 60 ° C. or more, and the upper limit is more preferably 90 ° C. or less. Reaction time is usually 30 minutes or more.
It is about 4 hours.

The glass transition temperature of the copolymer emulsion thus obtained is -60 to 50 ° C, and the lower limit is preferably -50 ° C. The upper limit is 20
° C, more preferably 0 ° C. Glass transition temperature is -6
When the temperature is lower than 0 ° C., the flexibility and tackiness of the coating film become too strong. Also, the solvent resistance generally decreases. On the other hand, when the temperature exceeds 50 ° C., the coating film becomes hard and brittle, and when it is used for the purpose of imparting flexibility by mixing with clay, its effect is reduced.

The undercoat agent for release paper of the present invention containing such a copolymer emulsion can be used as an undercoat agent for release paper as it is, or can be mixed with a pigment such as clay. Can also be used. The mixing ratio with the pigment such as clay is not particularly limited, but the mixing ratio can be 1000 parts by weight or less of the pigment such as clay with respect to 100 parts by weight of the copolymer emulsion in terms of solid content. Pigments in which polyvinyl alcohol, starch, and the like are previously blended can be used as the pigment such as clay.

When the undercoat agent for release paper of the present invention is applied to a backing paper, a cross-linking 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 method of applying 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. Furthermore, the film may be subjected to a calendering treatment to prepare a desired smoothness.

[0028]

The undercoat agent for release paper comprising the copolymer emulsion of the specific monomer mixture of the present invention is:
Suitable for easy-recovery release paper, solvent, water and silicone resin penetrate into the paper layer and undercoat layer even when various types of solvent type, solventless type and emulsion type silicone resins are applied to the base paper. It has good adhesion to silicone resin without any problems, and has excellent coating properties and mechanical stability. Further, the undercoat agent for release paper comprising the copolymer emulsion of the present invention has a low viscosity despite its high concentration, so that a high coating amount is possible and excellent in operability. Furthermore, it can be stably mixed with clay at a high concentration, and can impart solvent resistance and flexibility to the clay coat layer.

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples.

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 charged with 52 g of water. Then, 61 g of n-butyl acrylate, 14 g of 2-hydroxyethyl methacrylate, and acrylonitrile 7
g, 18 g of acrylamide and 1 g of sodium methallylsulfonate and 1.5 g of sodium alkylbenzenesulfonate, and the mixture was heated under a nitrogen stream and heated at 70 ° C. to 2 g of potassium persulfate and 51 g of water. The aqueous solution was added to initiate the polymerization. After the reaction was carried out for 60 minutes so that the polymerization temperature did not exceed 80 ° C., the mixture was neutralized with ammonia to obtain a target copolymer emulsion. The obtained copolymer emulsion had a nonvolatile content of 50% by weight, a pH of 7.1 and a viscosity at 25 ° C. of 800 c.
ps. The glass transition temperature of the obtained emulsion polymer was -13 ° C.

Examples 2 to 7 and Comparative Examples 1 to 3 Example 1 was the same as Example 1 except that the types, amounts and solid contents of the components of the monomer mixture and the emulsifier were changed as shown in Table 1. Polymerization was carried out in the same manner to obtain various copolymer emulsions. Table 1 shows the properties of the obtained copolymer emulsion.

[0032]

[Table 1]

The meanings of the symbols described in Table 1 are as follows. SMAS: sodium methallyl sulfonate, SAS: sodium allyl sulfonate, DMAA: N,
N-dimethylacrylamide, IPAA: N-isopropylacrylamide, BA: n-butyl acrylate, 2
HEMA: 2-hydroxyethyl methacrylate, A
N: acrylonitrile, AM: acrylamide, emulsifier A: sodium alkylbenzene sulfonate, emulsifier B: sulfosuccinate (trade name: AEROSOL501,
Emulsifier C: polyoxyethylene nonyl phenyl ether (trade name Neugen EA-1)
70, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

(Preparation of Sample: Clear Coated Paper)
After preparing a coating solution prepared by diluting the copolymer emulsions obtained in Comparative Examples 1 to 7 and Comparative Examples 1 to 20% by weight, coating and drying the PPC paper so that the solid content becomes 3 g / m ^2. Was done. Using this as a sample, a performance test was performed according to the following method. Table 2 shows the results.

(Preparation of sample: clay coated paper)
7 and the 60% by weight clay aqueous solution were mixed with each other so that the solid content weight ratio of the copolymer emulsions obtained in Comparative Examples 1 to 3 was 1: 1. After adding water to 50% by weight, the mixture was stirred at a high speed with a homodisper and mixed to prepare a coating liquid. This was applied to PPC paper and dried so that the solid content was 6 g / m ² . Using this as a sample, a performance test was performed according to the following method. Table 2 shows the results.

(Solvent resistance) Dye (Sudan II)
A toluene solution containing 1% by weight was applied so as to have a concentration of 12 g / m ^2, and after 5 seconds, it was wiped off with a gauze, and the coated surface was visually observed according to the following criteria. Sex "was evaluated.

"Toluene oil repellency" ：: Almost no dyeing. Δ: Stained with dye but no strikethrough. ×: Complete strikethrough.

"Toluene barrier property" ：: No strikethrough and no pinholes. Δ: Pinholes are generated. ×: Complete strikethrough.

(Silicone Adhesion) A curing catalyst (Silcolease 90) was added to 100 g of solvent silicone (Silicolyse KF-100, manufactured by Arakawa Chemical Industries, Ltd.).
B, manufactured by Rhone Poulin Co., Ltd.) and adjusted to a concentration of 7% by weight with toluene.
m ² after coating on the above sample,
For 20 seconds. Then, at 20 ° C and 65% humidity
%, The coated surface was rubbed with a finger, and the peeled state of silicone was evaluated according to the following criteria. ：: Does not peel. Δ: Slightly peeled off. ×: Complete peeling.

(Clay Mixability) The state of the coating liquid prepared by the above method was evaluated according to the following criteria. ：: uniformly dispersed. The viscosity is also stable. Δ: Aggregates are slightly generated. It is slightly thicker. ×: Completely agglomerated.

(Coating Suitability) The clay coating solution prepared by the above method was applied to a Mayer bar coating machine PI-1210F.
The condition at the time of coating with ILMCOATER (manufactured by Tester Sangyo Co., Ltd.) was evaluated according to the following criteria. ：: The bar proceeds smoothly, and a uniform and smooth coated surface is formed. Δ: The bar was slightly caught and it was difficult to obtain a smooth surface. ×: The bar was completely caught and coating was extremely difficult or impossible.

[0042]

[Table 2]

In Comparative Example 1, good results were obtained in terms of performance. However, since the solid content concentration was lower than that of the Example (the viscosity of the copolymer emulsion was high), the viscosity of the clay coating solution was high. Was not able to be reduced, and the coating suitability was inferior to the examples. When the concentration of the emulsion of Comparative Example 1 was increased (Comparative Example 2) in the same manner as in the Example, the viscosity increased, and a clay coating liquid having an appropriate viscosity could not be prepared. Comparative Example 3 was inflexible due to a high glass transition temperature, and the coating film was cracked. In particular, the film was brittle in clay coating. Further, the copolymer emulsion obtained in Comparative Example 3 had a high viscosity, caused unevenness during coating, and generated many pinholes in a solvent resistance test.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 141: 00) (C08F 220/12 220: 56 228: 02)

Claims (5)

[Claims] (A) a monomer having one (meth) allyl group as a carbon-carbon double bond and / or (B) a general formula (1): CH ₂ ＣC (R ¹ ) -CONR ²
(R ³ ) (wherein, R ¹ is a hydrogen atom or a methyl group, R ²
Is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³ is a linear or branched alkyl group having 1 to 4 carbon atoms). And (C) a monomer mixture comprising a nonionic vinyl monomer excluding the component (B) in the presence of an emulsifier, and having a glass transition temperature of -6.
An undercoat agent for release paper containing a copolymer emulsion at 0 to 50 ° C. 2. The component (C) comprises: (a) 30 to 85% by weight of an alkyl (meth) acrylate having 4 to 8 carbon atoms in an alkyl group; and (b) 5 to 5% of a hydroxyl group-containing (meth) acrylate.
2. The composition according to claim 1, comprising 60% by weight and (c) 10 to 65% by weight of a nonionic vinyl monomer other than (a) and (b).
The undercoat agent for release paper according to the above. 3. The undercoat agent for release paper according to claim 2, wherein the nonionic vinyl monomer (c) contains acrylamide. 4. The amount of component (A) and / or component (B) used is 0.01 to 10 parts per 100 parts of component (C).
The undercoat agent for release paper according to claim 1, which is a part. 5. The undercoat agent for release paper according to claim 1, further comprising a pigment in addition to the copolymer emulsion.