JP5881496B2 - Undercoat for release substrate - Google Patents

Description

    The present invention relates to a release paper, release sheet, etc., for a release substrate having high smoothness and high gloss while retaining conventional solvent resistance, heat resistance and blocking resistance by applying to the substrate. It relates to a primer.

Conventionally, silicone dissolved in an organic solvent has been used as a release material component used in release paper. The silicone is very expensive, and it is necessary to obtain sufficient peeling performance with a coating amount as small as possible.
Therefore, in general, a sealing treatment is performed on the undercoat layer so that the silicone release material does not penetrate into the paper substrate, and then silicone is applied.
As such a sealing material, clay coating, a material coated with a water-soluble polymer such as polyvinyl alcohol or starch, polyethylene or the like is used after laminating (Patent Document 1). Moreover, there exists what apply | coated resin emulsions, such as an acrylic ester copolymer emulsion (patent document 2).
Although clay coating has heat resistance, it has poor adhesion to silicone, and water-soluble polymers such as polyvinyl alcohol and starch have a coating layer that is brittle, inferior in water resistance, and high in humidity. When it is stored only, it is easy to block. Furthermore, since it is a water-soluble polymer, it has a high viscosity, and its workability and drying properties are poor. Further, a laminate obtained by laminating polyethylene or the like has characteristics such as smoothness and flexibility, but is inferior in heat resistance.
Furthermore, the resin emulsion is excellent in film-forming properties, but is inferior in heat resistance and solvent resistance and lacks a sealing effect. A water-based emulsion composition with a two-layer structure obtained by polymerizing a vinyl monomer containing (meth) acrylamide in the presence of seed particles containing acrylonitrile is proposed as a sealing layer with excellent heat resistance and solvent resistance. (Patent Document 3). In this method, a sealing layer excellent in solvent resistance and heat resistance is provided. Recently, in addition to heat resistance and solvent resistance, smoothness and high glossiness at the time of applying the sealing layer are required. These points were insufficient.

U.S. Pat. No. 3,403,045 JP-B 63-54035 JP-A-3-121170

    The present invention overcomes the above-mentioned drawbacks of the prior art and provides a primer for a release substrate having high smoothness and high gloss while maintaining solvent resistance, heat resistance and blocking resistance. .

As a result of intensive investigations for solving the above problems, the present inventors have found that in a water-based emulsion containing a water-soluble resin (a) containing a (meth) acrylamide and organic particles (b), the resin (a It was found that the weight average molecular weight measured by the multi-angle light scattering method was less than 200,000. That is
[1] An acrylic aqueous dispersion that is a coating applied on a release substrate, the coating including a water-soluble resin (a) containing (meth) acrylamide and organic particles (b). A primer for a release substrate having a weight average molecular weight of a) of less than 200,000.
[2] An undercoat for a release substrate, wherein the organic particles (b) are particles obtained by polymerizing one or more vinyl monomers in the presence of the water-soluble resin (a).
[3] A primer for a release substrate, which is a resin obtained by polymerizing water-soluble resin (a) in the presence of organic particles (b) obtained by polymerizing one or more vinyl monomers.
[4] A primer for a release substrate obtained by mixing the water-soluble resin (a) and the organic particles (b).
[5] An undercoat for a release substrate containing 10 to 100% by weight of (meth) acrylamide in a solid content of 100 parts by weight of the water-soluble resin (a).
[6] Peeling in which the weight ratio of the water-soluble resin (a) to the organic particles (b) is (a) 10 to 90% by weight and (b) 90 to 10% by weight in the solid content of the acrylic aqueous dispersion. Base coat for base material.

    The primer of the present invention is applied to paper, film, cloth, etc., so that the primer for a peeling substrate having high smoothness and high gloss while maintaining the conventional solvent resistance, heat resistance and blocking resistance. It is an agent. In particular, when the release paper is prepared, when it is used as an undercoat agent, when a solvent-type release agent is applied thereon, an excellent release coating liquid sealing effect can be obtained.

    The release substrate of the present invention is made of a metal plate such as iron, copper, aluminum, and stainless steel in addition to a paper substrate, or polyethylene terephthalate, polyvinyl chloride, polyethylene, polypropylene, an ethylene-vinyl acetate copolymer, and the like. It can be selected from organic polymer films or fibrous substrates such as pulp, polyethylene, polypropylene, and polyester.

The primer of the present invention is an acrylic aqueous dispersion containing a water-soluble resin (a) containing (meth) acrylamide and organic particles (b).
The water-soluble resin in the present invention is defined as a resin having a transmittance of 85% or more of light having a wavelength of 400 nm at a concentration of 10% by weight in a medium mainly composed of water. It means a resin that forms a particulate form in a medium mainly composed of the above and has a light transmittance of 85% or less at a wavelength of 400 nm at a concentration of 10% by weight.
The acrylic water dispersion may be present in any form of the water-soluble resin (a) and the organic particles (b), and is a resin composition obtained by separately synthesizing and mixing (a) and (b). Both the form, the form of the resin composition obtained by polymerizing in the presence of (b), and the form of the resin composition obtained by polymerizing in the presence of (a) (b) are the present invention. Is within the range.

From the viewpoint of storage stability of the aqueous dispersion, the form of a resin composition obtained by synthesizing one resin in the presence of either the resin (a) or (b) is preferable. Furthermore, (b) is more preferably in the form of a resin composition obtained by polymerization in the presence of (a).
In the solid content of the acrylic water dispersion, the weight ratio of the resin solid content of the water-soluble resin (a) to the organic particles (b) is 10 to 90% by weight for (a) and 90 to 10% by weight for (b). Preferably, (a) is 20 to 80% by weight (b) is 80 to 20% by weight. When (a) is less than 10% by weight, the dispersion stability and adhesion are insufficient, and sufficient gloss cannot be obtained. Moreover, when it exceeds 90 weight%, there exists a possibility of producing a remarkable thixotropy characteristic.

  The volume average particle diameter of the acrylic aqueous dispersion according to the present invention is not particularly limited, but is 10 to 1,000 nm, preferably 10 to 800 nm, (particle size analyzer FPAR-1000 (Otsuka Electronics Co., Ltd.)). If present, it is preferable because of excellent water dispersion stability. If the thickness is less than 10 nm, the dispersion stability may be lowered, and if it exceeds 1,000 nm, the storage stability with time may be impaired. The method for controlling the particle size is not particularly limited, but can be appropriately adjusted depending on, for example, the amount of the surfactant.

The resin solid content concentration of the acrylic aqueous dispersion according to the present invention is 5 to 80% by weight, preferably 10 to 70% by weight. Within this range, good adhesion can be obtained.
In addition, by directly applying the aqueous dispersion of the present invention to a substrate, a coated substrate having excellent smoothness and high glossiness with Oken-type smoothness of 2000 seconds or more and 75 ° gloss value of 90 or more. Can be obtained.

Water-soluble resin (a)
The water-soluble resin (a) of the present invention is a resin containing at least (meth) acrylamide. Here, (meth) acrylamide means methacrylamide and acrylamide. In the present invention, methacrylamide is preferred from the viewpoint of adjusting the viscosity of the aqueous dispersion. The water-soluble resin (a) of the present invention may contain, in addition to (meth) acrylamide, a polymerizable monomer of an unsaturated carboxylic acid, and further one or more vinyl monomers. Here, methacrylic acid is preferred as the polymerizable monomer for the unsaturated carboxylic acids. The one or more vinyl monomers are preferably vinyl monomers having a functional group, such as amide group-containing vinyl monomers such as acrylamide, and carboxyl group-containing vinyl monomers such as (meth) acrylic acid. Hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate, glycidyl group-containing vinyl monomers such as glycidyl (meth) acrylate, cyano group-containing vinyl monomers such as (meth) acrylonitrile, N, N -Amino group-containing vinyl monomers such as dimethylaminoethyl (meth) acrylate, acetoacetoxy group-containing vinyl monomers such as acetoacetoxyethyl (meth) acrylate, sulfones such as sodium styrenesulfonate and sodium methallylsulfonate Examples include acid-containing monomers. Moreover, you may use hydrophobic vinyl monomers, such as styrene and (meth) acrylic acid ester. Further, a crosslinkable vinyl monomer may be used for the water-soluble resin (a), and examples of the monomer include methylene bis (meth) acrylamide, divinylbenzene, polyethylene glycol chain-containing di (meth) acrylate, and the like. It can be illustrated. Moreover, you may contain a 2 or more vinyl group as a crosslinkable vinyl monomer.

Moreover, in order to adjust the molecular weight of water-soluble resin (a), a polymerization initiator and a molecular weight modifier are used.
Examples of the polymerization initiator include hydrogen peroxide, persulfates such as ammonium persulfate and potassium persulfate, azobiscyanovaleric acid, 2,2′-azobis (2-amidinopropane) dihydrochloride, and 2,2′-azobis. [2- (N-phenylamidino) propane] dihydrochloride, 2,2′-azobis {2- [N- (4-chlorophenyl) amidino] propane} dihydrochloride, 2,2′-azobis {2- [ N- (4-hydroxyphenyl) amidino] propane} dihydrochloride, 2,2′-azobis [2- (N-benzylamidino) propane] dihydrochloride, 2,2′-azobis [2- (N-allyl) Amidino) propane] dihydrochloride, 2,2′-azobis {2- [N- (2-hydroxyethyl) amidino] propane} dihydrochloride, azobisisobutyronitrile, 2,2′-azobis {2- Methyl-N- [1,1-bis (hydroxymethyl -2-hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide}, 2,2′-azobis [2-methyl- Azo compounds such as N- [2-hydroxyethyl] propionamide] and 2,2′-azobis (isobutylamide) dihydrate; cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl Organic peroxides such as peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, lauroyl peroxide, and the like can be used, and one or more of these can be selected. The polymerization initiator is preferably water-soluble, and the amount of a general initiator used is 0.1 to 10% by weight, preferably 0.5%, based on the total weight of (co) polymerized monomers. -5.0 wt%.

  Examples of the molecular weight modifier include sodium methallyl sulfonate, n-dodecyl mercaptan, 1-thioglycerol and the like. The amount used of the molecular weight modifier is 0.1 to 10% by weight, preferably 0.1 to 5 parts by weight, based on the total weight of the (co) polymerized monomer, based on the total solid content of the water-soluble resin. .

  The weight average molecular weight calculated | required by the gel permeation chromatography (GPC) of water-soluble resin (a) is less than 200,000 by multi-angle light scattering detection, Preferably it is 1000-150,000, More preferably, it is 5000-100,000. . By setting the molecular weight of the water-soluble resin in the above range, the film forming property and the resin leveling property in the drying process are improved, and a highly smooth and highly glossy coated surface can be obtained. Furthermore, by reducing the molecular weight of the water-soluble resin, it is possible to reduce the viscosity of the dispersion, and the ripple effect is extremely high, such as improved handling properties. When the water-soluble resin has a weight average molecular weight of less than 1000, the film has excellent smoothness and gloss when formed into a film, but the coating film strength is insufficient and the strength of the coated paper may be reduced. In addition, sufficient heat resistance, solvent resistance, and blocking resistance may be reduced. Conversely, when it is 200,000 or more, excellent heat resistance, solvent resistance, and blocking resistance can be obtained, but sufficient glossiness and smoothness cannot be obtained.

  In 100 parts by weight of the solid content of the water-soluble resin (a), the amount of (meth) acrylamide used is 10 to 100% by weight, preferably 50 to 100% by weight, from the viewpoints of heat resistance, solvent resistance and blocking resistance. The vinyl monomer is 0 to 90% by weight, preferably 0 to 50% by weight.

Organic particles (b)
The organic particles (b) are preferably a (co) polymer emulsion obtained by emulsion polymerization of one or more vinyl monomers.

  As vinyl monomers, aromatic vinyl monomers, acrylic esters, methacrylic esters, unsaturated carboxylic acids, unsaturated sulfonic acids, hydroxyl group-containing vinyl compounds, aromatic vinyl compounds, unsaturated amides, amino Alkyl acrylates or aminoalkyl methacrylates, or quaternary chlorides thereof, such as methyl halides, ethyl halides, benzyl halides, N-aminoalkylacrylamides or N-aminoalkylmethacrylamides, or methyl halides thereof, Examples include quaternary chlorides, vinyl esters, vinylidene halides, diacrylates, dimethacrylates, and the like with ethyl halide, benzyl halide, and the like.

Examples of the aromatic vinyl monomer include styrene, p-methylstyrene, α-methylstyrene, 2-methylstyrene, t-butylstyrene, chlorostyrene, vinylxylene, vinylnaphthalene, vinylanthracene, vinylanisole, and divinylbenzene. .
As acrylic esters, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, Examples thereof include alkyl esters of 1 to 12 carbon atoms of acrylic acid such as decyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate.

  Methacrylic acid esters include ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 21-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, Examples thereof include alkyls having 1 to 12 carbon atoms and esters of methacrylic acid such as dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate.

  Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, acrylic anhydride, methacrylic anhydride, maleic anhydride, itaconic anhydride, and fumaric anhydride.

  Examples of the unsaturated sulfonic acids include 2-sulfoethyl methacrylate, t-butyl acrylamide sulfonic acid, styrene sulfonic acid, and salts thereof.

    Examples of hydroxyl-containing vinyl compounds include 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, polyethylene glycol monomethacrylate, polypropylene Examples include glycol monomethacrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, and glycerol monomethacrylate.

  As unsaturated amides, acrylamide, methacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-methylol Examples include methacrylamide, N-methylol acrylamide, diacetone acrylamide, and maleic amide.

  As aminoalkyl acrylates or aminoalkyl methacrylates, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-dimethylaminopropyl acrylate, N, N-dimethylaminopropyl methacrylate, N, N -T-butylaminoethyl acrylate, N, N-t-butylaminoethyl methacrylate, N, N-monomethylaminoethyl acrylate, N, N-monomethylaminoethyl methacrylate and the like can be mentioned.

  Examples of N-aminoalkyl acrylamide or N monoaminoalkyl methacrylamide include N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminoethyl acrylamide, N, N- And dimethylaminoethyl methacrylamide.

Examples of vinyl esters include vinyl acetate and vinyl propionate.
Examples of vinylidene halides include vinylidene chloride and vinylidene fluoride.
Examples of diacrylates include polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, and polypropylene glycol diacrylate.

  Dimethacrylates include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6- Hexanediol dimethacrylate, neopentyl glycol dimethacrylate and the like can be mentioned.

  Other monomers include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, allyl medaacrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, vinyl chloride, Vinyl ether, vinyl ketone, vinyl amide, chloroprene, ethylene, propylene, isoprene, butadiene, vinyl pyrrolidone, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, acrylonitrile, methacrylonitrile, isopropenyl- α, α-dimethylbenzyl isocyanate, ants Examples include lumercaptan.

Particularly suitable as the one or more vinyl monomers are methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate. 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile and the like.
More preferably, (b) should contain 10 to 70% by weight of acrylonitrile from the viewpoint of water resistance and solvent resistance.

If necessary, a crosslinkable vinyl monomer may be used. Examples of the monomer include methylene bis (meth) acrylamide, divinylbenzene, polyethylene glycol chain-containing di (meth) acrylate and the like. Moreover, you may contain a 2 or more vinyl group as a crosslinkable vinyl monomer. For the purpose of adjusting the molecular weight, a molecular weight modifier such as n-dodecyl mercaptan or 1-thioglycerol can also be used.
The glass transition temperature Tg of the organic particles (b) is not particularly limited, but is preferably −30 to 80 ° C. (according to calculation software CHEOPS (ver. 4.0)). If it is less than -30 degreeC, a tack | tuck remains after resin coating and is unpreferable.

Production of organic particles (b) The method for synthesizing the organic particles (b) is not particularly limited, but emulsion polymerization carried out in a solvent containing water as a main component is preferred. A surfactant or a water-soluble polymer can be appropriately used for the purpose of improving the polymerization stability and storage stability of the organic particles (b). Examples of the surfactant include an anionic surfactant and a nonionic surfactant.
Examples of the anionic surfactant include dodecylbenzene sulfonate, lauryl sulfate, alkyl diphenyl ether disulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, stearate, oleate, dioctyl sulfosuccinate, Examples thereof include polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, dialkyl sulfosuccinate, tert-octylphenoxyethoxy polyethoxyethyl sulfate, and the like.

 Nonionic surfactants include, for example, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyalkylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene Styrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, oxyethylene / oxypropylene block copolymer, t-octylphenoxyethyl polyethoxy Examples include ethanol and nonylphenoxyethyl polyethoxyethanol. Is mentioned.

These dispersing agents can select 1 type (s) or 2 or more types.
Water-soluble polymers used for the purpose of improving polymerization stability and storage stability may be added. Examples of these water-soluble polymers include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, (meth) Examples thereof include water-soluble polymers such as acrylic acid (co) polymers, poly (meth) acrylamide (co) polymers, and ethylene glycol.
Examples of the polymerization initiator include the types described above.

Although there is no restriction | limiting in the polymerization temperature at the time of the synthesis | combination of an organic particle (b), it synthesize | combines in the range of 30-95 degreeC when manufacturing time, the conversion rate (reaction rate) of a monomer into a copolymer are taken into consideration. It is preferable to carry out, and 50-85 degreeC is especially preferable.
Moreover, at the time of superposition | polymerization, it is also possible to use PH preparation agent, EDTA which is a metal ion sealing agent, or its salt for the purpose of improving manufacturing stability. After forming the copolymer emulsion, the pH may be adjusted with a general neutralizing agent such as ammonia, organic amine, potassium hydroxide, sodium hydroxide, or lithium hydroxide.

In the aqueous dispersion of the present invention, an aqueous polymer such as celluloses, starch and polyvinyl alcohol, a crosslinking agent such as a melamine resin, a formaldehyde resin, and an aqueous epoxy resin, and a filler as long as the desired effects of the present invention are not impaired. An antifoaming agent, a wetting agent, a leveling agent, a film forming aid and the like can be appropriately added.
The aqueous dispersion thus obtained can be directly applied to paper, film, cloth, etc., or mixed with inorganic pigments such as calcium carbonate, clay, titanium oxide, or organic pigments such as plastic pigments, and such water dispersion. When the body is used as a pigment binder and applied to paper or the like, a film excellent in solvent resistance, blocking resistance and heat resistance can be obtained.
For example, the coated surface such as a release paper undercoat, a back surface treatment agent, a diazo photosensitive paper binder, and an offset master binder is useful in applications where solvent resistance, blocking resistance, and heat resistance are required.

In particular, when producing release paper, an excellent effect of the release agent coating solution as an undercoat for applying a solvent-type release agent was obtained. It is also useful as a back-treatment agent for release paper that requires blocking resistance and heat resistance.
In addition, when used as a binder for diazo photosensitive paper and a binder for offset masters, it has good miscibility with inorganic pigments, and a stable pigment coating solution can be obtained. was gotten.

   EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these various examples. In addition, all the parts and% in various examples represent parts by weight and% by weight unless otherwise specified.

<Preparation of emulsion composition>
Production Example 1
<Synthesis of water-soluble resin containing amide group>
A separable flask equipped with a stirrer and reflux cooling was charged with 200 parts by weight of distilled water, replaced with nitrogen gas, and then heated to 80 ° C. Next, 2.0 parts of ammonium persulfate was added, and a mixture of vinyl monomer and water having the following composition was continuously added over 2 hours with stirring, and then aged at the same temperature for 2 hours to complete the polymerization. It was. An aqueous resin solution having a solid content of 20.0% was obtained.
The weight average molecular weight by GPC (multi-angle light scattering method, DAWN EOS ^™ manufactured by Wyatt Technology, Co.) was 150,000.

(Mixture of vinyl monomer and water)
Methacrylamide 65.0 parts Methacrylic acid 10.0 parts 2-Hydroxyethyl methacrylate 20.0 parts Methyl methacrylate 5.0 parts Sodium methallyl sulfonate 0.5 parts Distilled water 200.0 parts

Production Example 2
<Synthesis of organic particles>
A separable flask equipped with a stirrer and reflux cooling was charged with 360 parts by weight of distilled water, replaced with nitrogen gas, and then heated to 80 ° C. Next, 2.0 parts of ammonium persulfate was added, and then a vinyl monomer emulsion having the following composition was continuously added over 3 hours and held for 3 hours to complete the polymerization. A copolymer resin having a solid content of 20.0% was obtained.

(Vinyl monomer emulsion)
Styrene 30.0 parts n-butyl acrylate 65.0 parts Methacrylic acid 5.0 parts Ammonium lauryl sulfate 0.1 part Distilled water 40.0 parts

Example 1
<Production of emulsion containing water-soluble resin containing amide group and organic particles>
The water-soluble resin containing an amide group obtained in Production Example 1 and the organic particles obtained in Production Example 2 were mixed at a dry weight ratio of 33:67 to produce a copolymer emulsion.

Example 2
<Preparation of an emulsion containing a resin obtained by emulsion polymerization in the presence of a resin containing an amide group>
360 parts of distilled water for solid content adjustment was added to 250 parts of the aqueous resin solution obtained in Production Example 1, and the temperature was raised to 75 ° C. while replacing with nitrogen again. Next, 2.0 parts of ammonium persulfate was added, and then a vinyl monomer emulsion having the following composition was continuously added over 3 hours and held for another 3 hours to complete the polymerization. An emulsion having a solid content of 20.0% was obtained.

(Vinyl monomer emulsion)
Styrene 30.0 parts n-butyl acrylate 65.0 parts Methacrylic acid 5.0 parts Ammonium lauryl sulfate 0.1 part Distilled water 40.0 parts

Example 3
<Preparation of an emulsion containing a resin obtained by emulsion polymerization in the presence of a resin containing an amide group>
Except for increasing the amount of sodium methallylsulfonate added as a chain transfer agent to 5 parts, the same operation as in Production Example 1 was repeated to obtain a water-soluble resin containing an amide group. Next, an emulsion was obtained by the same operation as in Example 2 using the obtained water-soluble resin.
The weight average molecular weight by GPC was 15,000.

Example 4
<Preparation of an emulsion containing a resin obtained by emulsion polymerization in the presence of a resin containing an amide group>
Except changing to the composition shown in Table 1, the same operation as in Example 3 was performed to obtain a copolymer emulsion.
The weight average molecular weight by GPC was 15,000.

Example 5
<Emulsion obtained by polymerizing water-soluble resin containing amide group in the presence of organic particles obtained by polymerizing one or more vinyl monomers>
The organic particle dispersion 2000 parts obtained in Production Example 2 was heated to 75 ° C. while being purged with nitrogen again. Next, 2.0 parts of ammonium persulfate was added, and a mixture of the vinyl monomer and water having the following composition was continuously added over 2 hours with stirring, and then aged at the same temperature for 2 hours to complete the polymerization. It was. An emulsion having a solid content of 20.0% was obtained.

(Mixture of vinyl monomer and water)
Methacrylamide 65.0 parts Methacrylic acid 10.0 parts 2-Hydroxyethyl methacrylate 20.0 parts Methyl methacrylate 5.0 parts Sodium methallyl sulfonate 0.5 parts Distilled water 200.0 parts

The weight molecular weight by GPC was 150,000.

Example 6
Except changing to the composition shown in Table 1, the same operation as in Example 3 was performed to obtain a copolymer emulsion.
The weight molecular weight by GPC was 60,000.

Example 7
Except changing to the composition shown in Table 1, the same operation as in Example 3 was performed to obtain a copolymer emulsion.
The weight molecular weight by GPC was 15,000.

Comparative Example 1
Except changing to the composition shown in Table 1, the same operation as in Production Example 1 was performed to obtain a water-soluble resin containing an amide group.
The weight molecular weight by GPC was 200,000.

Comparative Example 2
Except changing to the composition shown in Table 1, the same operation as in Example 2 was performed to obtain a copolymer emulsion.

Comparative Example 3
Except changing to the composition shown in Table 1, the same operation as in Example 5 was performed to obtain a copolymer emulsion.

Comparative Example 4
Instead of the copolymer emulsion, an aqueous polyvinyl alcohol solution (degree of saponification of 95% or more, degree of polymerization of 1700, solid content of 10%) was used as it was.

[Evaluation method]
(1) Toluene resistance The obtained aqueous emulsion and aqueous solution were applied to a glass plate and dried at 120 ° C. for 5 minutes to prepare a test film. The obtained film was cut into 30 mm square and weighed (W0). Next, after immersing this film in toluene for 24 hours, the toluene was lightly wiped off and weighed (W1).
The film swelling rate by toluene was calculated by the following calculation formula.
Swell rate (%) = (W1-W0) / W0 × 100
A: Swell rate 0%
○: Swell ratio 1 to 10%
Δ: Swell rate 11% to 30%
X: Swelling ratio of 31% or more (2) Heat resistance Each resin (solid content 20%) was applied to commercially available high quality paper with a bar coater # 20 and dried at 120 ° C. for 30 seconds to prepare a test paper. The obtained test paper was cut into a 10 cm square, aged at 100 ° C. for 10 minutes, and then the coated surfaces were put together and a load of about 3 kg · f / cm was applied under the condition of 160 ° C., taken out after 10 seconds, and melted. The degree of wearing was confirmed.

◎: No fusion at all ○: No fusion but there is a feeling of adhesion △: There is a partial fusion ×: There is a full fusion
(3) 75 ° gloss Each resin (solid content 20%) was applied to commercially available coated paper with a bar coater # 16, dried at 120 ° C for 1 minute, and then aged at 100 ° C for 10 minutes to obtain a test paper. It was. About 75 degree glossiness of the application surface of the obtained test paper, it measured using the glossiness meter (Nippon Denshoku Co., Ltd. VG7000).

A: 95-100
○: 90-94
Δ: 85-90
X: 84 or less (4) Each resin (solid content 20%) was applied to a commercially available coated paper with a bar coater # 16, dried at 120 ° C. for 1 minute, and then aged at 100 ° C. for 10 minutes. Obtained. About the smoothness of the coated surface of the obtained test paper, it measured using the Oken type | mold smoothness meter (made by Asahi Seiko Co., Ltd.).

◎: 5000 seconds or more ○: 3000 to 5000 seconds △: 1000 to 3000 seconds ×: 1000 seconds or less

Claims (6)

A coating applied on a release substrate,
The paint is
A water-soluble resin (a) containing (meth) acrylamide as a raw material monomer to be polymerized,
An acrylic aqueous dispersion comprising organic particles (b) which are polymers of vinyl monomers comprising aromatic vinyl monomers or acrylonitrile, acrylic esters and unsaturated carboxylic acids ,
An undercoat for a release substrate, wherein the resin (a) has a weight average molecular weight of less than 200,000.   The release substrate according to claim 1, wherein the organic particles (b) are particles obtained by polymerizing one or more kinds of vinyl monomers in the presence of the water-soluble resin (a). For undercoat.   The water-soluble resin (a) described above is a resin obtained by polymerization in the presence of organic particles (b) obtained by polymerizing one or more kinds of vinyl monomers. The primer for peeling substrates as described.   The primer for a release substrate according to claim 1, wherein the primer is obtained by mixing the water-soluble resin (a) and the organic particles (b).   The release substrate according to any one of claims 1 to 4, wherein the content ratio of (meth) acrylamide is 10 to 100% by weight in 100 parts by weight of the raw material monomer solid content of the water-soluble resin (a). For undercoat. In the solid content of the acrylic water dispersion, the weight ratio of the water-soluble resin (a) to the organic particles (b) is (a) 10 to 90% by weight, and (b) 90 to 10% by weight. The undercoat agent for a peeling substrate according to any one of claims 1 to 5.