JPH0459336A - Sheet for thermocurable coating - Google Patents

Abstract

PURPOSE:To obtain a sheet having ductility and flexibility at a curing temperature or lower, by a method wherein the title sheet is comprised of a composition containing mainly of a reactive compound having a reactive functional group and reactive vinyl group, a curing agent which is capable of reacting with a reactive vinyl monomer and reactive functional group and a photopolymerization initiator. CONSTITUTION:A composition for a sheet containing mainly of a reactive compound having a reactive functional group and a reactive vinyl group, a curing agent which is capable of reacting with a reactive vinyl monomer and a reactive functional group and photopolymerization initiator is applied to process paper at a fixed thickness and then the title sheet is obtained by allowing ultraviolet rays to react with the reactive vinyl group by applying the ultraviolet rays to the composition. The reactive compound possesses at least one piece of the reactive functional group in at least one kind out of an OH group, NH3 group and COOH group within a molecule and possesses at least one piece of a reactive unsaturated group such as the vinyl group. For example 2-amino ethyl (meth)acrylate and epoxy acrylate oligomer are available as the reactive compound. Isocyanate, melamine and epoxy are available as the curing agent. Benzoinalkylether series and acetophenone series are used as the photopolymerization initiator.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention can be applied to the surface of articles such as furniture and steel plates, and can be applied for decoration, display, surface protection, corrosion prevention such as rust prevention, etc. This relates to sheets (or films) for

(Prior Art) Conventionally, paints have generally been used to decorate or display the surfaces of articles. Since paints usually contain organic solvents, their impact on the working environment (pollution, hygiene hazards) is a problem.

Furthermore, while water-based paints pose no problems in terms of the working environment, they do have problems in workability, such as long drying times (or a large amount of energy required for drying).

Recently, sheet-like pasting materials based on polyvinyl chloride have been proposed. The material used in this sheet form does not affect the working environment, and since it is in a sheet form, there is no need for drying. However, since this sheet-like adhesive is mainly made of a soft polyvinyl chloride sheet, there is a drawback that the hardness and scratch resistance of the coating are poor.

As a method for improving such drawbacks, a method has been proposed in which the sheet material is hardened after being attached to the surface of the article. For example, in Japanese Patent Publication No. 57-13425, a porous sheet-like base material is impregnated with a radical initiator,
A thermosetting composite sheet has been proposed in which a layer containing a polymer, a radically reactive monomer, etc. is laminated on one or both sides. In addition, Japanese Patent Publication No. 60-21630 discloses that a powder containing a radically reactive unsaturated compound that is solid at room temperature and a powder that is solid at room temperature are contained in a self-supporting continuous layer made of thermoplastic and/or rubbery material. A heat-curable sheet material suitable for coating the surface of an article has been proposed, which is made by blending a powder containing a radical reaction initiator.

(Problems to be Solved by the Invention) The sheet material disclosed in Japanese Patent Publication No. 57-13425 has a structure in which a layer containing a radically reactive unsaturated compound and a layer containing a radical reaction initiator are laminated. Therefore, in order to cause a uniform curing reaction in both layers, it is necessary to uniformly contact and heat both layers, which makes it difficult to control pressure and heating. In addition, since paper, woven fabric, or non-woven fabric is used as the sheet-like base material to be impregnated with the radical reaction initiator, when coating articles with uneven or curved surfaces, the sheet does not stretch easily and forms a good coating. It's difficult.

The sheet material disclosed in Japanese Patent Publication No. 60-21630 is relatively malleable and is thought to be able to be applied to the surface of an article having an uneven or curved surface. However, since it is necessary to mix the radically reactive unsaturated compound and the radical reaction initiator in solid form, the same compounds must be mixed using a non-uniform method such as freeze-grinding and powder heating when manufacturing sheet materials. As a result, mixing tends to be non-uniform, causing problems not only in surface performance but also in appearance, such as pigment dispersibility.

The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to have spreadability and flexibility before curing and excellent workability, and to apply it uniformly by heating afterwards. An object of the present invention is to provide a thermosetting coating sheet capable of forming a cured film with high hardness and hardness.

(Means for Solving the Problems) The thermosetting coating sheet of the present invention comprises a reactive compound having a reactive functional group and a reactive vinyl group, a reactive vinyl monomer, and a curing sheet capable of reacting with the reactive functional group. The sheet composition is composed of a sheet composition containing as main components a photopolymerization initiator and a photopolymerization initiator, and is obtained by forming a film by irradiating ultraviolet rays, thereby achieving the above object.

The thermosetting coating sheet of the present invention has extensibility to the extent that it can be applied to the surface of an adherend having a three-dimensional curved surface (irregularities, etc.) before curing, and is highly flexible. This sheet is a thermosetting coating sheet that can be cured by heating the sheet after being applied to an adherend to cause the curing agent contained in the sheet to react with the reactive functional groups of the reactive compound. This thermosetting coating sheet is usually obtained by coating process paper with the above-mentioned sheet composition to a certain thickness and then irradiating it with ultraviolet rays to react the reactive vinyl groups to form a film.

The reactive compound having a reactive functional group and a reactive vinyl group used in the present invention includes an OH group, an NH2 group,
It is a compound that has one or more reactive functional groups of one type (also known as one kind) and has one or more reactive unsaturated groups such as vinyl groups.Such compounds are Usually liquid. Examples of such compounds include 2-aminoethyl (meth)acrylate, 2-aminoethyl (meth)acrylate,
Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy 3-
Phenoxypropyl acrylate, polypropylene gelicol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, glycerol monomethacrylate, 2-acryloyloxyethylsuccinic acid,
Examples include 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, glycerol di(meth)acrylate, and an epoxy acrylate oligomer represented by the general structural formula (1).

These compounds can be used alone or in combination.

(R,=H or CH3) Examples of the curing agent that can react with the reactive functional group of the above-mentioned reactive compound include incyanate curing agents, melamine curing agents,
There are epoxy hardeners.

The isocyanate curing agent is an incyanate compound having two or more incyanate groups in the molecule, such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, toridine diisocyanate, triphenylmethane triisocyanate,
Iris (incyanate phenyl) thiophosphite, p-phenylene diisocyanate, xylylene diisocyanate, bis(incyanate methyl) cyclohexane, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, inphorone diisocyanate and trimethylolpropane adducts, incyanurate-modified products, biuret-modified products, carbodiimide-modified products, urethane-modified products, allophanate-modified products, etc. of these monomers. The amount of incyanate added varies depending on the method of forming the sheet, but the amount of NCO group relative to the amount (number) of reactive functional groups in the reactive compound is: reactive functional group: NC0 = 1: 0.3 ~
It is about 1.5. Moreover, blocked isocyanate in which inocyanate groups are blocked with phenol or the like can also be used.

Melamine curing agents are trimethylol melamine, hexamethylol melamine, which is produced by reacting formaldehyde with materials having polyfunctional amino groups such as melamine, urea, thiourea, guanidine, guanamine, acetoguanamine, benzoguanamine, dicyandiamide, and guanamine. It is an etherified melamine resin made by reacting dimethylol urea, dimethylol guanidine, dimethylol acetoguanamine, dimethylol benzoguanamine, etc. with an alcohol such as butyl alcohol or propyl alcohol. It is difficult to determine the amount of these melamine crosslinking agents added based on the reactive group value of the reactive compound like incyanate curing agents, so when adding them, conduct preliminary experiments before making the sheet. It is preferable to decide the amount to be added. Regarding this sheet formation, the amount of reactive functional groups in the compound (
Functional group reactive with respect to number): OR (ether value) =
1: preferably about 0.3 to 1.5.

The epoxy curing agent is a glycidyl compound of polyhydric alcohol, and is usually used together with a Lewis acid catalyst. Examples of epoxy curing agents include butadiene cidoxide, hexacin dioxide, diglycidyl ester of phthalic acid, diglycidyl ether of bisphenol-A, diglycidyl ether of bisphenol-F, triglycidyl ether amine of para-aminophenol, and diglycidyl ether of aniline. Examples include glycidyl compounds such as diglycidyl ether, tetraglycidyl ether of phenylenediamine, diglycidyl ether of sulfonamide, and triglycidyl ether of glycerin, as well as polyether-modified diglycidyl, polyester-modified diglycidyl, and urethane-modified diglycidyl compounds (polymers). The amount of this epoxy compound added is preferably about 3 to 1.5, based on the amount (number) of reactive functional groups of the above-mentioned reactive compound: reactive functional groups: CH2CH2O (epoxy group) = 1:Q .

The amount of these curing agents added is preferably the amount stated above, but in reality, depending on the reactivity of the reactive functional group of the reactive compound used, the curing agent is added at the same time as the reaction with the reactive functional group of the compound. For example, reactions occur between melamine hardeners and between melamine hardeners and epoxy hardeners, so it is preferable to conduct preliminary experiments before making a decision.

Any commonly used photopolymerization initiator can be used, and benzoin alkyl ether, acetophenone, benzophenone, thioxanthone, and the like are often used. For example, benzoin ether types include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc.; acetophenone types include 2.2°-jethoxyacetophenone, 2.2-dibutoxyacetophenone,
2-hydroxy-2-methylpropiophenone, p-t
Benzophenone types such as er-butyltrichloroacetophenone include benzophenone, 4-chlorobenzophenone, 4.4°-dichlorobenzophenone, 3.3-dimethyl-4-methoxybenzophenone, and dibenzosuberone; thioxanthone types include thioxanthone, 2-
Chlorothioxanthone, 2-methylthioxanthone, 2
-isopropylthioxanthone, 2-ethylanthraquinone, etc. Regarding the amount of photoinitiator added,
Although the appropriate amount differs depending on each material, it is 0.5-2.0 parts per 100 parts by weight of the reactive compound. It is preferably within the range of parts by weight. Moreover, the photopolymerization initiator is not limited to one type, but can be used in combination of two or three types.

As the above-mentioned reactive vinyl monomer, (meth)acrylic and styrene materials are suitable as materials that have good compatibility with a reactive compound having a reactive functional group and a reactive vinyl group. For example, (meth)acrylics include methyl (meth)acrylate, ethyl (meth)acrylate,
From monofunctional types such as benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, phenoxygelene glycol (meth)acrylate; 1,6-hexadiol di(meth)acrylate, neopentyl glycol di(meth)acrylate , polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylpropane tri
(meth)acrylate, pentaerythritol tri(
Multifunctional types such as meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate are applicable. In the styrene series, styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, p-ethoxystyrene, p-phenylstyrene, p-ethoxystyrene,
Various styrene derivatives such as p-chlorostyrene, m-chlorostyrene, and o-chlorostyrene can be used. The amount of these compounds added is 1 to 1,00 parts by weight per 100 parts by weight of the reactive compound having a reactive functional group and a reactive vinyl group.
The amount is adjusted to 0 parts by weight, preferably 100 to 600 parts by weight. In addition, the reactive vinyl monomer is
It is not limited to one type, but can be combined with two or three types. Addition of reactive monomers often has the effect of increasing the spreadability and flexibility of the thermosetting coating sheet before curing (it is also effective as a means of controlling spreadability and flexibility). .

The thermosetting coating sheet of the present invention can be produced by thoroughly and uniformly kneading the above-mentioned materials using an organic solvent, if necessary, using a casting method such as a knife coater, a comma coater, or a reverse coater. Release-treated PET (polyethylene terephthalate, paper, etc.) is coated and heat-dried to remove the solvent to create a thermosetting coating sheet. In this heating and drying step, the curing agent reacts with the reactive compound, and the thermosetting coating sheet comes to have properties such as spreadability and flexibility necessary for application to an adherend.

The film thickness of the thermosetting coating sheet of the present invention varies depending on the adhesion of the sheet to the adherend and the function imparted to the adherend. From this point of view, the range of about 20 to 500 μm is preferable, but when pasting on a flat surface, the range of about 5 to 1.000 μm is also acceptable.

The following materials may be added to the thermosetting coating sheet of the present invention as necessary.

Colorants such as pigments and dyes may be included in the sheet composition. As for the colorant, pigments, dyes, etc. used in ordinary painting can be used. For example, pigments include titanium oxide, iron oxide, carbon black, and cyanine pigments; dyes include azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes; and aluminum flakes, nickel powder, and gold powder. , metal powder such as silver powder. The amount of colorant that can be added depends on the type of constituent components of the sheet composition, the thickness of the sheet, the type of colorant, etc., but it is within the range that can be formed into a sheet by irradiation with ultraviolet rays. Needless to say. These sheet compositions contain inorganic fillers, metal materials, anti-aging agents, rust preventive agents, etc. in an amount that allows the sheet to be cured by ultraviolet rays in order to control the surface and improve functionality. It doesn't matter if it is included.

When the thermosetting coating sheet of the present invention has low rigidity at room temperature, it becomes difficult for the thermosetting coating sheet to maintain its shape. In such a case, by providing a support layer on the thermosetting coating sheet, the shape retention of the sheet can be improved. This support layer is
Although it is used to maintain the shape of the entire sheet, flexibility may be imparted to the support layer when it is attached to a three-dimensional curved surface or the like with this support layer. For example, a rubber-like material is used, or a thermoplastic or thermosetting material that becomes malleable when heated or the like is used. These supporting layers may be peeled off immediately after pasting and the sheet is cured, or they may be cured while being attached to the adherend and serve as a protective layer until the adherend is used. It can also be used as Furthermore, the surface shape (surface condition) of the thermosetting coating sheet can be adjusted by providing embossing or patterns on the surface of the support layer.

Next, the obtained sheet is applied to an adherend, and the sheet is cured by heating to obtain a coating. Various methods can be used to attach it to the adherend. For example, there are methods such as manual pasting, laminator method, (vacuum) pressing, insert injection (in-mold coating), vacuum adhesion molding (vacuum packaging molding), etc., but these methods can improve adhesion to the adherend and prevent rust. In order to improve properties, etc., vacuum contact molding, vacuum pressing, etc. in which a vacuum is created between the adherend and the thermosetting coating sheet are preferred. The heat curing of the thermosetting coating sheet is preferably carried out for a predetermined period of time that satisfies the use (reaction) conditions of the curing agent used.

(Effects) The thermosetting coating sheet of the present invention is a thermosetting sheet that has spreadability and flexibility at a temperature below the curing temperature, and forms a strong film after being heated and cured. Therefore, before heating,
It is possible to coat not only flat surfaces but also adherends with some unevenness or three-dimensional curved surfaces, and a good coating without wrinkles can be formed.

Since the thermosetting coating sheet of the present invention is formed into a sheet by irradiation with ultraviolet light from an ultraviolet lamp or the like, the sheet composition is not heated to high temperatures during film formation. Therefore, for example, when a blocked isocyanate is used as a post-curing agent, it has the characteristic that it does not decompose during the film forming process.

This thermosetting sheet material can be integrally molded with resin □ in the painting and injection molding of not only automobiles, home products, and building materials, but also furniture, decorative accessories, etc., which are currently being painted. It can also be done.

(Example) The present invention will be specifically described below based on examples.

Note that "parts" means "parts by weight."

Fruit 1" 20 parts of 2-hydroxyethyl methacrylate, 50 parts of methyl methacrylate, 50 parts of butyl methacrylate, incyanate (manufactured by Nippon Polyurethane Industries, Coronate LS)
NC0=13.0%) 38 parts (this crosslinking agent has 1.0 equivalent of incyanate groups with respect to the OH groups of the acrylic polyol), and 0.0 parts of jetoxyacetophenone. 5 parts were mixed with good stirring. This mixture was applied with an applicator to the release surface of a silicone release-treated polyethylene terephthalate film (hereinafter referred to as PET film), and irradiated with 500 mJ using a high-pressure mercury lamp to produce a thermosetting sheet. The thickness of the sheet is 10
It was 0 μm, and no bubbles were generated.

Next, this sheet was heated to 50°C by vacuum contact molding (vacuum packaging molding) on a hemisphere with a radius of 15 cm coated with acrylic melamine, and the ultimate vacuum level was 10 Tor.
I attached it when it reached r. It was heated and cured at 160"C for 130 minutes to create a coating. The hardness of this coating was a pencil hardness, and the H11 property was 100710 in the 1-width base test.
It was 0.

20 parts of 2-aminoethyl methacrylate, 50 parts of methyl methacrylate, 50 parts of butyl acrylate, 100 parts of melamine curing agent (Dainippon Ink Chemical Co., Ltd., Super Beckamine (butylated melamine resin, J-820-60)) (This crosslinking agent has 1
, with 0 equivalents of isocyanate groups), and jetoxyacetophenone 0. 5 parts of the mixture was mixed with stirring. This mixture was applied to the release surface of the PET film using an applicator and irradiated with a high-pressure mercury lamp for 50011 IJ hours to create a thermosetting sheet. The thickness of the sheet was as follows:
It was 120 μm, and no bubbles were generated.

Next, this sheet was attached to an acrylic melamine coated hemisphere with a radius of 15 cm by vacuum contact molding (vacuum packaging molding) and heated to 50° C., and when the ultimate vacuum degree reached 10 Torr. This was heated and cured at 110° C. for 30 minutes to form a coating. The hardness of this coating was a pencil hardness, and the H11 property was 1007100 in the liIm width board test.

Acrylic polyamine (MW = 11
0,000) 120 parts, blocked isocyanate (Nippon Polyurethane Co., Ltd., Coronate 2513, ethyl acetoacetate block NGO = 10.2%) 51 parts (this crosslinking agent has 1.0 equivalent f for the amine group of the acrylic polyamine)
i) having an incyanate group) and 0.5 part of jetoxyacetophenone were dissolved and mixed in 200 parts of ethyl acetate. This mixture was applied to the release surface of the PET film using an applicator and dried by heating at 80° C. for 10 minutes to prepare a thermosetting sheet. The thickness of the sheet is 120
μm, and no bubbles were generated.

Next, when I tried to attach this sheet to a hemisphere with a radius of 15 cm coated with acrylic melamine and heated it to 50°C by vacuum contact molding (vacuum packaging molding) and when the ultimate vacuum reached 10 Torr, the sheet broken,
Could not paste. It was found that this was due to insufficient elongation of the sheet, and that the acrylic polyol partially reacted with the blocked incyanate due to heating during film formation, resulting in crosslinking.

To 120 parts of 2-hydroxyethyl methacrylate, incyanate (Coronate L, manufactured by Nippon Polyurethane Industries, Ltd.) was added.
NC0 = 13.0%) 38 parts (this crosslinking agent has 1.0 equivalent of isocyanate groups with respect to the OH group of the acrylic polyol), jetoxyacetophenone 0.59
Mixed well with stirring. This mixture was applied to the release surface of the PET film using an applicator and irradiated with 500+aJ using a high-pressure mercury lamp, but the polymer was too brittle to be used as a thermosetting sheet.

that's all

Claims (1)

[Claims] 1. A sheet composition containing as main components a reactive compound having a reactive functional group and a reactive vinyl group, a reactive vinyl monomer, a curing agent capable of reacting with the reactive functional group, and a photopolymerization initiator. A thermosetting coating sheet obtained by forming a film by irradiating it with ultraviolet rays.