JPH0538797A - Manufacture of coated material and sheet for coating - Google Patents

Abstract

PURPOSE:To form a rigid film on the surface of an article with irregularities and a curved surface such as the housing of an OA equipment. CONSTITUTION:A clear layer composed of a photo-setting or electron-ray curing resin composition and under an uncured or semirigid state, a colored layer consisting of a resin composition and a base material layer are laminated in the order, thus forming a sheet for coating. The sheet is stuck on an adherend, and the clear layer of the sheet is irradiated with light or electron rays, thus curing the sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coating having a hard coating on its surface and a coating sheet used in this method. More specifically, the invention relates to a vehicle body for corrosion prevention, decoration, display, etc. The present invention relates to a method for producing a covering and a covering sheet in which a covering sheet is attached and cured on the surface of an article such as a housing or sanitary of OA equipment and home electric appliances.

[0002]

2. Description of the Related Art Conventionally, paint is generally used to decorate the surface of an article or to give an indication to the surface of the article. Usually, the paint uses an organic solvent, so that the influence on the working environment (contamination, harmful to hygiene) is a problem. Further, in the water-based paint, the work ring does not pose a problem, but there is a problem that the drying time becomes long or a large amount of energy for drying is required.

Recently, sheet-like adhesive materials mainly composed of polyvinyl chloride have been proposed. When this sheet is used, there is no effect on the work environment, and because it is in sheet form, there is no need to dry it. However, this sheet-shaped patch material mainly uses a soft polyvinyl chloride sheet, and has a drawback that it is inferior in hardness and scratch resistance.

As a method for improving this, there has been proposed a method in which a sheet material is cured after being attached. For example, in JP-B-57-13425, a porous sheet-shaped substrate is impregnated with a radical initiator, and a layer containing a polymer and a radical-reactive monomer is laminated on one or both sides of the substrate. Thermosetting composite sheets have been proposed.

Further, Japanese Patent Publication No. 60-21630 discloses a powder containing a radical reactive unsaturated compound which is solid at room temperature and a room temperature in a self-supporting continuous layer made of a thermoplastic and / or rubber material. A heat-curable sheet material prepared by mixing powder containing a solid radical reaction initiator has been proposed.

[0006]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 57-1342
The sheet disclosed in Japanese Patent Publication No. 5 has a structure in which a layer having a radical-reactive unsaturated compound and a layer having a radical reaction initiator are laminated, and therefore, the sheet is made uniform to perform a uniform curing reaction. There is a drawback that it is difficult to control these because it is necessary to pressurize and heat. In addition, since paper, woven fabric, and non-woven fabric are used as the sheet-shaped base material impregnated with the radical reaction initiator, when coating the surface of an article having irregularities or curved surfaces, it is difficult to obtain sheet elongation and a good film is formed. Difficult to do.

The sheet disclosed in Japanese Examined Patent Publication No. 60-21630 has spreadability and is considered to be able to be attached to irregularities or curved surfaces. However, in order to manufacture a sheet, since operations such as freeze pulverization and powder mixing are required, a non-uniform coating film is likely to be formed, and there is a problem not only in surface performance of the sheet but also in appearance such as pigment dispersibility. ..

The present invention solves the above problems and provides a method for producing a coated article and a coating sheet which can be decorated with excellent scratch resistance and chemical resistance.

[0009]

The method for producing a coated article of the present invention comprises a uncured or semi-cured clear layer made of a photocurable or electronically curable composition, and a colored layer made of a resin composition. , A substrate layer and a covering sheet laminated in this order are attached to an adherend, and then the clear layer of the covering sheet is irradiated with light or an electron beam to cure the clear layer, and The coating sheet of the present invention has a clear layer in an uncured or semi-cured state made of a photocurable or electron beam curable composition, a colored layer made of a resin composition, and a base material layer in this order. They are laminated, so that the above-mentioned object is achieved.

The present invention will be described in detail below.

The photocurable composition for forming the clear layer is, for example, a compound having a reactive double bond such as a vinyl group in the molecule (not limited to low molecular weight compounds, but also includes polymers). An initiator necessary for photocuring, a base (coloring layer, and optionally a base material layer) protective material, for example, an ultraviolet absorber, and, if necessary, a high molecular weight material for improving sheet retention, for example, a resin. Those whose main components are and are mentioned.

The electron beam curable composition for forming the clear layer is, for example, a compound having a reactive double bond such as a vinyl group in the molecule, a base protective material (ultraviolet absorber), and if necessary. Those containing a resin as a main component are mentioned.

Examples of the compound having a reactive double bond in the molecule include a (meth) acryloyl group, for example,
Monofunctional type such as methyl (meth) acrylate, ethyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate,
6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate , Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

There are also oligomers such as polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligo acrylate, alkyd acrylate and polyol acrylate. Further, examples thereof include a styrene monomer having a vinyl group or an allyl group, α-methylstyrene, divinylbenzene, vinyl acetate, pentene, hexene, and an unsaturated compound. These compounds further introduce polar groups such as a hydroxyl group, an amino group, a carboxyl group, a carbonyl group, and an epoxy group in order to improve the adhesion with the printing layer (described later) and the compatibility with the undercoat protection material. Sometimes.

The photo-curing polymerization initiator is added when the above-mentioned double bond does not react and cure only by irradiating light, particularly when it is cured by ultraviolet rays. This polymerization initiator is usually called a photoinitiator, and for example, a benzoin alkyl ether-based, acetophenone-based, benzophenone-based, thioxanthone-based photoinitiator is preferably used.

Examples of the benzoin ether type include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin propyl ether.

Examples of the acetophenone type include 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, p-ter-butyltrichloroacetophenone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

Benzophenone, benzophenone,
4-chlorobenzophenone, 4,4'-dichlorobenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, dibenzosuberenone and the like.

The thioxanthone type includes thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone and 2-ethylanthraquinone.

The photoinitiator is added in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the above compound. Further, the photoinitiator is not limited to one type, and two or more types may be used in combination.

As the material for protecting the underlayer, a commercially available ultraviolet absorber or the like can be used. The material to be added is selected from those having good dispersion stability in the composition and not being modified by light irradiation. For example, phenyl salicylate, p-tert butyl phenyl salicylate, salicylic acid such as p-octyl phenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy Benzophenone such as -4-dodecyloxybenzophenone, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert
-Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole and other benzotriazoles, 2-ethylhexyl-2-cyano-3, There are cyanoacrylate materials such as 3'-diphenyl acrylate and ethyl-2-cyano-3,3'-diphenyl acrylate.

The UV absorber is added in an amount of 0.01 to 3 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the above compound. Further, the ultraviolet absorber is not limited to one type in order to improve the undercoat protection, and it is preferable to use two or more types in combination. Further, a hindered amine light stabilizer or an antioxidant may be added.

The high molecular weight material as a sheet retainability improving material does not have a reactive double bond added for improving the handleability (flexibility) of the sheet and the tack of the sheet surface. A material having good compatibility with the compound having is selected. For example, when the compound having a double bond has a urethane skeleton and a (meth) acryloyl group, an acrylic resin or polyester resin made of methyl methacrylate, a urethane resin, or the like can be used.

At this time, there is SP (solvability parameter) as a standard, and a combination of materials having similar values is preferable. In addition to this, a fluororesin, a silicone resin, etc. are used for this high molecular weight substance. Further, in order to improve the adhesion with the printing layer (described later) and the compatibility with the undercoat protection material, these high molecular weight substances may further contain a hydroxyl group, an amino group,
A polar group such as a carboxyl group, a carbonyl group or an epoxy group may be introduced.

A peroxide may be added to the clear layer, if desired. As the peroxide, a usual organic peroxide can be used. More preferably, in view of storage stability at room temperature, an organic peroxide having a decomposition temperature of 100 ° C or higher. It includes, for example, 2,2-bis (tert-butylperoxy) butane, tert-butylperoxybenzoate, di-tert-butylperoxyisophthalate, methyl ethyl ketone peroxide, dicumyl peroxide, tert-butylperoxy. There is acetate.

The amount of the peroxide added is 0.5 to 100 parts by weight of the low molecular weight product having the (meth) acryloyl group.
A range of 5.0 parts by weight is preferred. Further, the peroxide is not limited to one type, and two or more types may be used in combination. By adding these peroxides, it is possible to further heat-cure the portion that is hard to be cured by irradiation with light.

If necessary, a small amount of a coloring agent such as a pigment or a dye and a high hardness fine particle material for increasing hardness are added to the clear layer. The colorant may be a pigment or dye used in paint. Examples of pigments include titanium oxide, iron oxide, carbon black, cyanine pigments, and quinacridone pigments. Examples of dyes include azo dyes, anthraquinone dyes, indigoid dyes, and stilbenzene dyes. Also, aluminum flakes, nickel powder,
You may use metal powders, such as gold powder and silver powder, as a coloring agent. It is preferable that these materials are fine particles.
Further, fine particles (average particle diameter: 20 nm or less) of titanium oxide, silica, diamond, etc. are used as a material for increasing hardness.

When a material is added, it is preferable that the above-mentioned photoinitiator undergoes an initiating reaction with light having a wavelength with which absorption of a colorant is small.

The combinations of materials centering on acrylics will be shown below. The materials can be similarly combined in other systems.

(A) Weight average molecular weight of 20,000 to 1,00
A photocurable clear layer mainly composed of an acrylic resin which is solid at room temperature and has a double bond in the molecule (b), and a photoinitiator (c).

(D) At least one selected from the group consisting of hydroxyl group, amino group and carboxyl group in the molecule
Having multiple functional groups, the weight average molecular weight is 20,000 to 1,00
Acrylic resin which is solid at room temperature and is 0,000, (b) a low molecular weight compound having a double bond in the molecule, (c) a photoinitiator, (e) an isocyanate-based crosslinking agent, a melamine-based crosslinking agent and an epoxy. A photocurable clear layer containing, as a main component, at least one crosslinking agent selected from the group consisting of system crosslinking agents.

(F) Acrylic resin having a plurality of reactive double bonds in the molecule and having a weight average molecular weight of 20,000 to 1,000,000 and solid at room temperature, and (b) a low molecular weight having a double bond in the molecule. And a photocurable clear layer containing (c) a photoinitiator as a main component.

(G) At least one selected from the group consisting of hydroxyl group, amino group and carboxyl group in the molecule
An acrylic resin having a plurality of different functional groups and a plurality of reactive double bonds, having a weight average molecular weight of 20,000 to 1,000,000 and being solid at room temperature; and (b) a low molecular weight product having a double bond in the molecule, A photocurable clear layer containing, as a main component, c) a photoinitiator and (e) at least one crosslinking agent selected from the group consisting of an isocyanate crosslinking agent, a melamine crosslinking agent and an epoxy crosslinking agent.

As the electron beam curable clear layer, for example, a composition obtained by removing the photoinitiator from the above-mentioned photocurable clear layer is used.

The acrylic resin (a) having a weight average molecular weight of 20,000 to 1,000,000 and solid at room temperature contained in the clear layer is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate or the like. It can be obtained by copolymerizing the (meth) acrylic acid ester of, with a styrene derivative monomer or a maleic acid-based monomer in the presence of a reaction initiator (various peroxides, chain transfer agents, etc.).

The (d) molecule contained in the clear layer has a plurality of at least one functional group selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group, and has a weight average molecular weight of 20,000 to 1,000,000. Acrylic resins that are solid at room temperature include (meth) acrylic acid ester-containing (meth) acrylic acid ester monomers and 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. At least one of (meth) acrylic acid ester monomer having a hydroxyl group and (meth) acrylic acid ester monomer having an amino group such as 2-aminoethyl (meth) acrylate and 3-aminopropyl (meth) acrylate Monomers with functional groups and other (meth) acrylic acid esters and styrene derivatives Reaction initiator with mer and maleic acid type monomer (various peroxides, chain transfer agents, etc.)
It can be obtained by copolymerization in the presence of

An acrylic resin having a plurality of (meth) acryloyl groups in the molecule (f) contained in the clear layer and having a weight average molecular weight of 20,000 to 1,000,000 and solid at room temperature, and a hydroxyl group in the molecule (g). , A plurality of at least one functional group selected from the group consisting of an amino group and a carboxyl group and a (meth) acryloyl group, and having a weight average molecular weight of
Acrylic resins that are 20,000 to 1,000,000 and solid at room temperature include (meth) acrylic acid having a carboxyl group such as (meth) acrylic acid; 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth).
(Meth) acrylic acid ester monomer having a hydroxyl group such as acrylate; and (meth) acrylic acid ester monomer having an amino group such as 2-aminoethyl (meth) acrylate and 3-aminopropyl (meth) acrylate; 2- ( (Meth) acrylic acid ester monomers having aziridinyl such as 1-aziridinyl) ethyl (meth) acrylate and 2- (1-aziridinyl) butyl (meth) acrylate; and having epoxy groups such as glycidyl (meth) acrylate (meth) Among the acrylic acid ester monomers, etc., a monomer having at least one kind of functional group and other (meth) acrylic acid ester, styrene derivative monomer, maleic acid-based monomer, etc. are used as reaction initiators (various peroxides and chain transfer). Functionalities that can be obtained by copolymerization in the presence of The acrylic copolymer having a can be obtained by adding a monomer having a functional group.

These acrylic resins (a), (d),
The weight average molecular weights (Mw) of (f) and (g) can be changed depending on the conditions when carrying out the polymerization reaction using a reaction initiator. The acrylic resin used in the present invention is
Those having a weight average molecular weight in the range of 20,000 to 1,000,000 are preferably used.

If the weight average molecular weight is less than 20,000, sufficient elongation cannot be obtained for stretching during the sheet sticking operation,
Cracks may occur. Weight average molecular weight is 1,
When it exceeds, 000,000, it is difficult to dissolve in a solvent and it becomes difficult to prepare a coating sheet from the photocurable resin composition.

For example, when a sheet is prepared by solvent casting, the solvent viscosity increases, and therefore the resin can be cast only at a low concentration, which makes it difficult to increase the film thickness of the sheet.

These acrylic resins have a Tg (glass transition point) of -20 because of the relationship between the hardness after the sheet is cured and the scratch resistance.
Those in the range of ℃ to 100 ℃ are preferable. However, when the surface hardness is not too high, for example, 2B or less (23 ° C.) by the pencil hardness method, or when the elongation of the sheet is hardly required, it is applicable even if it is out of these ranges. Acrylic resins may be used in combination of different types as long as they have these molecular weight ranges.

Since the acrylic resins (d) and (g) have a functional group such as a hydroxyl group, an amino group and a carboxyl group, they are crosslinked by the above crosslinking agent, which can improve the flexibility of the sheet. ..

Functional group values of the above acrylic resins (d) and (g) {OH group value and NH ₂ group value (NH ₂ value: N added during polymerization)
The amount of H ₂ groups similar calculation or the OH number, which was quantified by changing the NH ₂ group to the OH group is reacted with nitrous acid) and COO
It is preferable that the total of H group value (COOH value: amount of COOH group added at the time of polymerization is calculated in the same manner as OH value, or COOH group is titrated with KOH)}.
When the functional group value is less than 2, improvement in flexibility of the sheet cannot be expected. Further, if the functional group value exceeds 50, sufficient elongation of the sheet cannot be obtained. However, when the elongation of the sheet is hardly required, it is applicable even if it is out of these ranges.

Since the acrylic resins (e) and (h) have functional groups such as hydroxyl group, amino group and carboxyl group, they are cross-linked by the above-mentioned cross-linking agent, whereby the flexibility of the sheet can be improved. .. Said reactive acrylic resin (e), the functional group value of (h) {OH group value and NH ₂ groups number (NH ₂ dihydric: similar to the OH value amount of NH ₂ groups to be added during the polymerization calculation or, NH ₂ COOH group value (quantified by reacting the group with nitrous acid to change it to OH group) and COOH value (COOH value: amount of COOH group added during polymerization is calculated in the same manner as OH value, or COOH group is titrated with KOH) } Sum is 2
Those in the range of up to 50 are preferred.

When the functional group value is less than 2, the improvement in flexibility cannot be expected. Further, when the functional group value is 50 or more, sufficient elongation of the sheet cannot be obtained. However, when the surface hardness is not too high, for example, 2B or less (23 ° C.) by the pencil hardness method, or when the elongation of the sheet is hardly required, it is applicable even if it is out of these ranges.

Also, these acrylic resin materials can be used as a block copolymer in which the reactive portion of the acrylic resin is block-shaped or comb-shaped. In this case, as the material that forms a block with these reactive acrylic resin materials, not only acrylic materials but also styrene-based materials, maleic acid-based materials, and imide-based materials having good compatibility with acrylics, silicone-based materials, and fluorine-based materials. Any combination of materials that can be blocked can be used. In this case, there are a method in which the weight average molecular weight of this material is within the above range and a method in which it is used, and a method in which the above-mentioned reactive acrylic resin is blended with these block polymers.

The low molecular weight compound having a double bond in the molecule (b) contained in the clear layer is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, benzyl (meth) acrylate or 2-ethoxyethyl. Monofunctional types such as (meth) acrylate and phenoxydiethylene glycol (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di Multifunctional such as (meth) acrylate, trimethylpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate There are types.

There are also oligomers such as polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligo acrylate, alkyd acrylate and polyol acrylate. These low molecular weight substances may further have functional groups such as a hydroxyl group, an amino group and a carboxyl group.

The amount of the low molecular weight substance added is almost related to the Tg of the acrylic resin and the viscosity of the low molecular weight substance to be added (plasticizing effect on the reactive acrylic resin). For example, Tg
= 60 ℃, when using acrylic resin, viscosity is 500cp
10-150 parts for low molecular weight substances below s (25 ℃), viscosity 500cps
It is preferable to add 50 to 300 parts of a low molecular weight substance (25 ° C.) or higher. If the added amount is too small, sufficient hardness and chemical resistance cannot be obtained after curing. If the amount added is large, the handleability of the sheet will deteriorate. The low molecular weight substances may be used in combination of different types.

The above-mentioned isocyanate-based cross-linking agent is an isocyanate compound having two or more isocyanate groups in the molecule, and examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, triphenylmethane triisocyanate and tris (isocyanate. Phenyl)
Monomers of thiophosphite, P-phenylene diisocyanate, xylylene diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc. Examples include methylolpropane adduct, isocyanurate modified product, biuret modified product, carbodiimide modified product, urethane modified product, and allophanate modified product.

The above-mentioned melamine-based cross-linking agent is trimethylolmelamine obtained by reacting formaldehyde with a material having a polyfunctional amino group such as melamine, urea, thiourea, guanidine, guanamine, acetoguanamine, benzoguanamine, dicyandiamide, and guanamine. Hexamethylol melamine, dimethylol urea dimethylol guanidine, dimethylol acetoguanamine, dimethylol benzoguanamine and the like are etherified melamine resins obtained by reacting with alcohols such as butyl alcohol and propyl alcohol.

The epoxy crosslinking agent is a glycidyl compound of a polyhydric alcohol containing a plurality of epoxy groups and is used together with a Lewis acid catalyst. The Lewis acid is preferably microencapsulated to delay the reaction.

For example, butadiene sidioxide, hexazine dioxide and diglycidyl ester of phthalic acid, bisphenol-A diglycidyl ether, bisphenol-F diglycidyl ether, paraaminophenol triglycidyl ether amine, aniline diglycidyl ether, Phenylenediamine tetraglycidyl ether, sulfonamide diglycidyl ether,
Examples thereof include glycidyl compounds such as triglycidyl ether of glycerin, polyether-modified diglycidyl, polyester-modified diglycidyl, urethane-modified diglycidyl compound (polymer), vinylcyclohexenedioxide, and dicyclopentadienedioxide.

The addition amount of these crosslinking agents is preferably such that the functional group value of the acrylic resin: the functional group value of the crosslinking agent = 1: 0.7 to 1.3. However, in reality, due to the reactivity with the acrylic resin used, the functional groups of the acrylic resin and the cross-linking agents, for example, the melamine-based cross-linking agents, the reaction of the melamine-based cross-linking agent and the epoxy-based cross-linking agent, etc. occur. It is preferable to decide.

The above-mentioned colored layer is a binder material in which the above-mentioned coloring agents such as pigments and dyes are favorably dispersed. As the binder material, an acrylic resin or urethane resin having a polar group such as a hydroxyl group or a carboxyl group, which has good pigment dispersibility, a polyester, or a vinyl chloride resin, an ABS resin, a PS resin, or the like, which also has good pigment dispersibility, , These modified materials and various copolymers. For example, acrylic resin is an acrylic polyol that is solid at room temperature (containing only hydroxyl groups and carboxyl groups), and when dispersing pigments in a solvent system, the material must be soluble in the solvent, so the weight average molecular weight Is preferably in the range of 20,000 to 1,000,000.

When the pigment is dispersed with a kneader, it may be out of this range. However, in order to make the color of the colored layer as vivid as the paint, it is necessary to increase the pigment concentration of the colored layer material, and therefore it is preferable to use a solvent system.
Further, the urethane resin is classified into a linear type and a crosslinked type.

When a linear type urethane resin is used, there are a method of forming a colored layer by casting as it is and a method of forming a colored layer by polymerizing at the time of casting film formation.

When the cross-linking type is used, it is preferable to form a sheet by the latter method. These materials are, for example, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, P-phenylene diisocyanate, xylylene diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, lysine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
Diisocyanates such as tetramethylxylylene diisocyanate and trimethylhexamethylene diisocyanate, polyester diols (condensation polyester diols, lactone polyester diols, polycarbonate diols, etc.), polyether diols and other diols, ethylene glycol, 1,4-butane diol, It is composed of a chain extender such as hydroquinone diethylol ether.

When the casting film is formed as it is,
These materials can be previously polymerized in a solution (a catalyst such as dibutyltin dilaurate may be added in order to accelerate this reaction).

In this case, the urethane resin preferably has a weight average molecular weight in the range of 20,000 to 1,000,000. If the weight average molecular weight is less than 20,000, the sheet is likely to be cracked during sheet spreading. When the weight average molecular weight exceeds 1,000,000, it becomes difficult to dissolve in a solvent, and for example, when a sheet is formed by solvent casting, the solvent viscosity becomes high, and therefore the resin can be cast only at a low concentration, and therefore the thick colored layer. Would be very expensive to create.

In the case of polymerizing at the time of casting, the above-mentioned low molecular weight materials or polymer materials obtained by polymerizing them are used, and a bifunctional isocyanate is further added to polymerize by heat during film formation to form a colored layer. Is.

As for the cross-linking type, as in the case of polymerizing at the time of casting described above, a low molecular weight material or a polymer material obtained by polymerizing them is used, and at least trifunctional or more functional isocyanate is further added to polymerize by heat during film formation. Then, the covering sheet is prepared.

These isocyanates are added within the range where the sheet can be spread (curved surface followability). For example, isocyanurate of hexamethylene diisocyanate and isocyanate such as trimethylolpropane adduct.
In addition to isocyanates, melamine crosslinkers may also be used. It is possible to further improve the solvent resistance of the covering sheet by using urethane partially cross-linked in this way.

The polyester resin used in the colored layer is
For example, there are a saturated type obtained from terephthalic acid and an ethylene glycol-based material, and an unsaturated type obtained from terephthalic acid and butadiene. The polyester resin preferably has a weight average molecular weight of 20,000 to 1,000,000.

When the weight average molecular weight is less than 20,000, the sheet is likely to be cracked when the sheet is spread. The weight average molecular weight is
If it exceeds 1,000,000, it becomes difficult to dissolve in a solvent, and for example, when a colored layer is formed by solvent casting, the solvent viscosity becomes high, so the resin can be cast only at a low concentration, and therefore a thick film sheet can be formed. Will be very expensive.

The base material layer is provided to further improve the handleability of the covering sheet. When the adhesion between the base material layer and the colored layer made of the resin composition is poor, it is preferable to provide a primer layer between the two layers. Since the sheet is stretched as necessary and attached to the adherend, it is preferable that the base material layer is composed of a film having a malleability at least under heating. This base material layer may optionally contain a colorant as described above.

Examples of the resin used for the base material layer include polystyrene, acrylic polymer, polycarbonate, polyvinyl chloride, polyethylene, polypropylene, ABS (acrylonitrile-butadiene-styrene copolymer) and the like.

In order to further improve the designability of the covering sheet used in the present invention, the sheet may be provided with a printing layer. In this case, the printing layer is preferably provided between the clear layer and the coloring layer.

[Preparation of Photocurable or Electron Beam Curable Sheet] As the sheet, a sheet which constitutes each layer of a clear layer, a coloring layer and a base material layer is calendered, extruded, casted or the like. And a method of separately laminating and laminating, a colored layer is formed by casting molding on the base material layer, and further, a light or electron beam curable layer is successively laminated by a casting method, or It can be prepared by a method such as laminating a clear layer on a release polyethylene terephthalate sheet by casting, laminating a coloring layer, and laminating this sheet on a base material layer.

Casting is performed by using a coating machine having a comma roll, a knife coater or the like.

The thickness of the light- or electron-beam curable sheet thus obtained is determined by the appearance of the molded product, performance such as scratch resistance and weather resistance. For example, when it is used as a molded product, that is, when the sheet is spread to reduce the sheet thickness, the initial film thickness is set so that the final thickness of the clear layer is at least 5 μm or more.

The covering sheet is preferably thicker than the above-mentioned minimum required film thickness of the clear layer by about 200 to 1,000 μm in total thickness of the base material layer and the coloring layer.

The thickness of the covering sheet used in the present invention thus obtained is preferably about 100 to 1,000 μm when it is applied to the surface of an uneven adherend, and 50 to when it is applied to a flat surface. It may be about 500 μm.

The electron beam is emitted from an electron beam accelerator having various shapes and sizes and is usually 20 to 1,000 keV, preferably 100 to 5 keV.
00 keV is used.

The ultraviolet light used for light irradiation is irradiated by a high-pressure mercury lamp or a metal halide lamp from each direction (particularly in the case of a three-dimensional shape), and the irradiation energy on the irradiation surface is 5 to 500 mW / cm ² , preferably It is set to 50 to 200 mW / cm ² .

[Uses of Cover Sheet] For example, exterior materials such as automobile bumpers, spoilers and exterior plates, interior materials such as instrument panels, exterior materials such as motorcycle kaure, and housing materials for office automation equipment and home appliances. Etc.,
Used to improve hardness, weather resistance, solvent resistance, and aesthetics.

[Production Method of Coated Product] The coating sheet of the present invention has various uses. In a method such as injection molding or stamping molding, in which a coating sheet is introduced into a mold in advance and is attached to a molded product at the same time as molding, the sheet is heated at room temperature or heated inside the mold to obtain vacuum and / or compressed air. It is brought into close contact with the mold by molding, and then ordinary molding is performed.

In a method for continuously producing a molded product such as extrusion molding or pultrusion molding, a method of introducing a coating sheet into a mold and simultaneously molding the molded product and attaching it to the surface of the molded product, sizing, There is a method such as pasting after cooling.

The method of introducing the coating sheet into the mold is usually carried out by winding the coating sheet in front of and in the middle of the mold. In the method of sticking the covering sheet after molding (immediately), it is usually carried out by sticking with a pressure roller along the surface of the molded product.

In vacuum (pressure) molding, the coating sheet (base material layer) of the present invention is laminated on a sheet to be molded in advance,
It is done in the usual way.

When the sheet is attached to a long member such as wood or aluminum sash, it can be performed using a commercially available profile laminator or the like. At this time, it is preferable to provide an adhesive layer on the sheet in order to improve the adhesiveness to the adherend. The coating sheet on which the pressure-sensitive adhesive is laminated is usually attached directly to the surface of the molded product by a hand or by using a double vacuum forming machine (sticking machine) or the like.

After the sheet is attached, the clear layer is cured by irradiating the clear layer with light or an electron beam and, if necessary, further heating, to cure the clear layer and finally obtain a coating.

Incidentally, in the method for producing a coated article, in order to attach the coating sheet to the adherend as is clear from the above description, the visco-adhesive action is not an essential requirement, and injection of the molding material, etc. Lamination by is also preferably used.

[0084]

[Function] A hard coating can be formed by pasting a coating sheet on the surface of a molded product and irradiating it with light or an electron beam. Therefore, it does not require a paint coating space as in the case of using a conventional paint. In addition, the working environment is not affected by the solvent.

Furthermore, since the clear layer of the coating film provided on the surface of the molded product is made of a photocurable or electron beam curable resin composition, it has excellent scratch resistance, chemical resistance and the like. The colored layer will be viewed from the outside. Further, since the covering sheet has excellent stretchability, it can be easily stuck even in deep drawing by sticking it to the adherend while stretching the sheet.

[0086]

EXAMPLES The present invention will be described in detail below based on examples. In addition, "part" means "part by weight".

(A) Materials used for each layer 1) Substrate layer I ABS sheet (manufactured by Sanpo Resin Co., Ltd., A20)
5, film thickness 500 μm) II ABS sheet (manufactured by Sanpo Resins Co., Ltd., A20)
5, film thickness 300 μm) III ABS sheet (manufactured by Sanpo Resins Co., Ltd., A10)
6, film thickness 300 μm) IV PVC sheet (manufactured by Sanpo Resin Industry Co., Ltd., film thickness 30)
0 μm) 2) Colored resin layer resin composition A Acrylic resin (copolymer of methylmethacrylate, methacrylic acid, and butylmethacrylate, weight average molecular weight 58,000, Tg = 80 ° C.) 100 parts Quinacridone red 50 parts Ethyl acetate Mixture of 300 parts or more with stirring.

B acrylic polyol (copolymer of methyl methacrylate, butyl acrylate and 2-hydroxyl ethyl acrylate, weight average molecular weight 450,00
0, Tg = 70 ° C) 100 parts Rutile titanium oxide 200 parts Ethyl acetate 300 parts A mixture of the above with stirring.

C Vinyl chloride resin (degree of polymerization: 900) 100 parts Rutile titanium oxide 200 parts Ethyl acetate 300 parts A mixture obtained by mixing the above with stirring.

D Reactive acrylic resin (copolymer of methyl methacrylate, butyl acrylate and 2-hydroxyl ethyl acrylate, Mw = 653,000, Tg = 45 ° C., OH
Value = 10) 100 parts Isocyanate crosslinking agent (Nippon Polyurethane Industry Co., Ltd.)
Manufactured by Coronate L, NCO = 13.0%, solid content 75%) 5.2 parts by solid content (this cross-linking agent has 1.2 equivalents of isocyanate groups based on the functional groups of the reactive acrylic resin) quinacridone red 50 parts ethyl acetate Mixture of 300 parts or more with stirring.

3) Resin composition for clear layer Acrylic resin (copolymer of methyl methacrylate, ethyl methacrylate and butyl acrylate, weight average molecular weight 183,000, Tg = 60 ° C.) 100 parts Acrylate monomer (Nippon Kayaku KAYARAD D
PCA-20) 50 parts 2,4-dihydroxybenzophenone 0.4 parts Phenyl salicylate 0.3 parts Ethyl acetate 300 parts A mixture of the above with stirring.

Acrylic resin (copolymer of methyl methacrylate, ethyl methacrylate, and butyl acrylate, weight average molecular weight 387,000, Tg = 80 ° C.) 100
Part Acrylate monomer (Nippon Kayaku Co., Ltd., KAYARAD D
PCA-20) 50 parts Photoinitiator (Nippon Ciba Geigy Co., Ltd., Irgacure 18)
4) 2 parts 2-Hydroxy-4-dodecyloxybenzophenone 0.7 parts 2- (2'-hydroxy-3 ', 5'-ditert-butylphenyl) benzotriazole 0.3 parts Ethyl acetate 300 parts The above components were mixed with stirring. blend.

Reactive acrylic resin (reactive acrylic resin obtained by adding 2-hydroxyethyl methacrylate to a copolymer of methyl methacrylate, butyl methacrylate, butyl acrylate, and acrylic acid,
Weight average molecular weight = 175,000, Tg = 40 Average double bond per molecule = 58) 100 parts Acrylate monomer (Nippon Kayaku Co., KAYARAD R)
604) 80 parts Photoinitiator (Nippon Ciba Geigy Co., Ltd., Irgacure 18)
4) 2 parts 2-Ethylhexyl-2-cyano-3,3'-diphenyl acrylate 0.8 parts Ethyl acetate 300 parts A mixture of the above with stirring.

Reactive acrylic resin (copolymer of methyl methacrylate, butyl acrylate and 2-hydroxyl ethyl acrylate, Mw = 186,000, Tg = 65 ° C., OH
Value = 5) 100 parts Acrylate monomer (Nippon Kayaku Co., Ltd., KAYARAD D
PCA-20) 100 parts Photoinitiator (Nippon Kayaku Co., Ltd., Kayacure DETX) 1 part Photopolymerization accelerator (Nippon Kayaku Co., Ltd., Kayacure EPA)
2 parts isocyanate cross-linking agent (Japan Polyurethane Industry Co., Ltd.)
Manufactured by Coronate L, NCO = 13.0%, solid content 75%) 2.2 parts by solid content (this crosslinking agent has an equivalent amount of isocyanate groups to the functional groups of the reactive acrylic resin) 2-hydroxy-4-dodecyl Oxybenzophenone 1.0 part Ethyl acetate 300 parts A mixture of the above with stirring.

Reactive acrylic resin (reactive acrylic resin obtained by adding 2-hydroxyethyl acrylate to a copolymer of methyl methacrylate, butyl acrylate and acrylic acid, weight average molecular weight = 175,000, Tg = 80 Average double bond per molecule = 18, COOH value = 5) 100 parts Acrylate monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., NPA-
10G) 50 parts Photoinitiator (2,4,6, -trimethyl benzoyl diphenylphosphine oxide) 1 part N-methyldiethanolamine 2 parts Isocyanate crosslinking agent (Nippon Polyurethane Industry Co., Ltd.)
Manufactured by Coronate L, NCO = 13.0%, solid content 75%) 2.2 parts by solid content (this crosslinking agent has an equivalent amount of isocyanate groups to the functional groups of the reactive acrylic resin) 2- (2'-hydroxy -3 ', 5'-ditert-aminophenyl) benzotriazole 1.0 part Ethyl acetate 300 parts A mixture of the above with stirring.

B) Preparation of Coating Sheet A resin composition for the coloring layer was applied onto the substrate layer and dried at 80 ° C. for 15 minutes to form a coloring layer, and the resin composition for the clear layer was further formed on the coloring layer. Was coated and dried at 80 ° C. for 15 minutes to form a clear layer to obtain a coating sheet.

Tables 1 and 2 show the base material layer, the coloring layer resin composition and the clear layer resin composition used in each example.
In Table 1, the thickness of the colored layer is 50 μm and the thickness of the clear layer is 30 μm. In Table 2, the thickness of the colored layer is 70 μm and the thickness of the clear layer is 50 μm.

C) Method for producing coated material-Simultaneous injection molding method The sheet was heated inside the mold to form a close contact by vacuum pressure molding, and then the molding resin was injected. The clear layer on the surface of the obtained molded product was irradiated with light or an electron beam.

Stamping Molding Method A sheet was heated inside the mold to form a close contact by vacuum pressure molding, and then a resin was introduced and the mold was closed. The clear layer on the surface of the obtained molded product was irradiated with light or an electron beam.

Simultaneous method of extrusion molding Immediately after the molded product came out of the mold, a sheet was attached before sizing and then irradiated with light. In this case, a covering sheet was used in which 30 μm of a SIS type hot melt adhesive was laminated on the back surface of the base material layer (the surface opposite to the colored resin layer).

D) Evaluation of Molded Articles (Coatings) As shown in Tables 1 and 2, the adhesiveness of the coating sheet obtained in each of the above Examples to the adherend and the hardness of the coating film after curing the sheet were measured. The weather resistance was evaluated.

The adhesiveness was determined by an adhesiveness test (the number of crosses remaining after peeling the tape) by a cross-cut test, and the hardness was determined by pencil hardness. The weather resistance was evaluated by the gloss retention rate and the color difference ΔE after 2000 hours of the sunshine weather meter. The results are shown in Tables 1 and 2.

[0103]

[Table 1]

[0104]

[Table 2]

Comparative Example A) Sheet I ABS Sheet (A205, manufactured by Sanpo Resins Co., Ltd.)
Film thickness 500 μm) II ABS sheet (manufactured by Sanpo Resins Co., Ltd., A106,
Film thickness 300 μm) B) Method for producing coated material The same method as in Example 1 was performed.

C) Evaluation of Molded Article (Coated Material) The same method as in Example 1 was carried out. The results are shown in Table 3.

[0107]

[Table 3]

[0108]

According to the method for producing a coated article of the present invention, a coating sheet having a clear layer composed of a photocurable or electron beam curable composition on the surface thereof is attached to the surface of an article, and the light or electron beam is applied. By irradiation, a film having excellent solvent resistance and scratch resistance can be formed on the surface of the article.

Therefore, in addition to being excellent in productivity, there is an advantage that the problem of the conventional coating space and the environmental problem such as the solvent are eliminated.

Further, since the covering sheet of the present invention has excellent stretchability before the clear layer is cured, it can be applied not only to a flat article but also to an article surface having irregularities or a curved surface. Furthermore, since the clearing layer, the coloring layer, and the base material layer are laminated in this order on the covering sheet, the coloring layer can be visually recognized from the outside through the clear layer, and the sheet is provided with a design property. Car,
There is an advantage that it is possible to easily and inexpensively decorate various plastic moldings and metal moldings such as a body of a motorcycle, an OA device, a housing of an electric home appliance, and a stationery.

Claims (2)

[Claims] 1. An uncured or semi-cured clear layer made of a photocurable or electron beam curable composition, a colored layer made of a resin composition, and a substrate layer laminated in this order. A method for producing a coated article, which comprises applying the coating sheet to an adherend, and then curing the clear layer by irradiating the clear layer of the coating sheet with light or an electron beam. 2. An uncured or semi-cured clear layer made of a photocurable or electron beam curable composition, a colored layer made of a resin composition, and a substrate layer laminated in this order. Covering sheet.