JPH0715015B2 - Thermosetting coating sheets and coatings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to a surface of an article such as furniture and a steel plate for corrosion prevention, decoration, display, etc. The present invention relates to a curable coating sheet and a coated article in which a semi-cured thermosetting resin layer is laminated on the surface of a workable adherend such as a metal plate.

(Prior Art) When a surface of furniture, a steel plate or the like is decorated or displayed, a paint is generally used. However, an organic solvent is usually used for the paint, and the organic solvent is volatilized during the work, which deteriorates the working environment and poses a problem of environmental hygiene. When a water-based paint is used, it does not impair the working environment, but there is a problem that the drying time becomes long or a large amount of energy is required to dry the paint.

Therefore, recently, a sheet-shaped adhesive material mainly composed of polyvinyl chloride has been proposed. This adhesive material is to be adhered to the surface of an adherend such as furniture or a steel plate, and when using this adhesive material, there is no adverse effect on the working environment,
Moreover, since it is a sheet, there is an advantage that it does not need to be dried. However, this sheet-shaped patch material is mainly formed of soft polyvinyl chloride, and has a drawback that it is inferior in hardness and abrasion resistance.

As a method for improving this, there has been proposed a technique of forming a coating film having high surface hardness by curing a sheet material after attachment. For example, in Japanese Examined Patent Publication No. 57-13425,
A thermosetting type obtained by impregnating a porous sheet-shaped substrate with a radical reaction initiator to form an initiator-impregnated sheet, and laminating a layer containing a polymer and a radical-reactive monomer on one or both sides of the sheet. Composite sheets have been proposed.

Further, JP-B-60-21630 discloses that thermoplasticity and / or
Alternatively, in a self-supporting continuous layer made of rubber, a powder containing a radical-reactive unsaturated compound solid at room temperature and a powder containing a radical reaction initiator solid at room temperature are held without contact. Sheet materials made of these materials have been proposed.

(Problems to be Solved by the Invention) A composite sheet disclosed in JP-B-57-13425 has a structure in which a layer having a radical reactive unsaturated compound and a layer having a radical reaction initiator are laminated. Because
In order to carry out a uniform curing reaction during heating and pressurization, it is necessary to bring both layers into uniform contact, which makes it difficult to control heating and pressurization and to form a uniform cured coating. Further, since paper, woven cloth, non-woven cloth, etc. are used as the sheet-like base material impregnated with the radical reaction initiator, when the composite sheet is coated on the surface of an adherend having irregularities or curved surfaces, the composite sheet Is difficult to stretch and "wrinkles" are easily formed, and it is difficult to form a good film on the surface of the adherend.

The sheet material disclosed in Japanese Patent Application Laid-Open No. 60-21630 has spreadability and is considered to be able to be attached to irregularities or curved surfaces.
However, in this sheet material, the powder containing the radical-reactive unsaturated compound and the powder containing the radical-reaction initiator exist via the thermoplastic resin layer or the like without direct contact, and Since both powders and the resin layer are melt-mixed by heating and reacted and cured, there is a drawback that the characteristics of the sheet material are easily influenced by the particle size and the mixing property of the powder. In the production, since the reaction starts when both powders come into contact with each other, it is necessary to pulverize and mix each powder in a frozen state, so that the mixing property is poor, and therefore a non-uniform coating film is easily formed, and the surface performance as well as the pigment There was a problem in appearance such as dispersibility.

On the other hand, as the coating, for example, as disclosed in JP-B-57-53145, the surface of the adherend such as a steel plate or various metal plates is coated with a low-molecular weight precoat metal coating,
The dry one is proposed.

However, in the above coating material, the coating material for precoat metal is completely cured, and after the cured coating film is formed on the surface of the adherend, the coating material is post-processed (bending processing by pressing etc., drawing processing). As a result, the coating film is apt to be cracked or peeled off, and the post-processing is greatly limited. Further, when the coating film hardness is set to be soft in consideration of the followability of the coating film due to the bending of the coated material, the coating film flows against the pressing pressure during processing, resulting in uneven thickness and impairing the flatness. On the contrary, when the coating material is initially cured (B-staged) in order to increase the hardness of the coating film, the resin of the coating film has a low molecular weight, so that the cracks and peeling described above occur during processing.

Therefore, most of the conventional coatings as the precoat metal have been used as a flat surface, and have drawbacks such that the coating film becomes very thin and the coating film hardness decreases even if it is bent.

The present invention solves the above-mentioned drawbacks, and an object of the present invention is to have good spreadability before curing, and also to cover an adherend surface having an uneven surface or a curved surface with good flexibility. The present invention is to provide a thermosetting coating sheet which can be formed into a uniform coating after curing and has a high hardness. Another object of the present invention is to perform post-processing such as bending and drawing without hindrance, without lowering the flatness of the coating or cracking, and to increase the hardness or thickness of the coating. To provide a coating.

(Means for Solving the Problems) The thermosetting coating sheet of the present invention has at least two kinds of functional groups selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group, and has a weight average molecular weight of 100,000 to 1,000,0
00, which is in an uncured or semi-cured state composed of a thermosetting resin composition containing a solid acrylic resin at room temperature and a blocked isocyanate as a main component, thereby achieving the above object. . The coating material of the present invention is obtained by applying a resin liquid containing the thermosetting resin composition to an adherend and reacting a part of the acrylic resin and a part of the blocked isocyanate contained in the resin liquid by heating. To form a thermosetting resin layer in a semi-cured state, thereby achieving the above object.

Further, the other thermosetting coating sheet of the present invention is an unblocked isocyanate, at least one crosslinking agent selected from the group consisting of melamine-based crosslinking agent and epoxy-based crosslinking agent, and the acrylic resin, It is in a semi-cured state composed of a thermosetting resin composition containing a blocked isocyanate as a main component, and thereby the above object is achieved. Another coating material of the present invention comprises applying a resin liquid containing the thermosetting resin composition to an adherend to form a thermosetting resin layer in a semi-cured state, thereby achieving the above object. To be done.

The thermosetting coating sheet of the present invention is formed by forming the thermosetting resin composition into a sheet shape, and this sheet can be attached to the surface of an adherend having a three-dimensional curved surface (uneven surface) before curing. It has a degree of malleability and is highly flexible. After the sheet is attached to the adherend, the reaction temperature of the blocked isocyanate (including the reaction temperature and above)
By heating the sheet, the blocking agent is released, and the functional group of the acrylic resin in the sheet is reacted with the isocyanate group of the blocked isocyanate to cure the sheet.

Further, the thermosetting resin composition may further contain at least one crosslinking agent selected from the group consisting of unblocked isocyanate, melamine-based crosslinking agent, and epoxy-based crosslinking agent. The thermosetting coating sheet obtained from the above is in a semi-cured state at room temperature because the crosslinking agent reacts with a part of the functional groups of the acrylic resin. Then, after sticking this sheet to an article, by heating to the reaction temperature of the blocked isocyanate, it is possible to completely cure the sheet by reacting the functional group of the acrylic resin in the sheet and the isocyanate group of the blocked isocyanate. it can. As described above, by using the semi-cured sheet, the sheet is further imparted with malleability and malleability to prevent cracks and cracks during processing,
Flatness can be imparted to enhance the appearance after curing.

The coating of the present invention is a resin liquid prepared by dispersing or dissolving each of the above thermosetting resin compositions in a solvent, applying the resin liquid to an adherend, and heating or crosslinking the above-mentioned crosslinking agent and an acrylic resin. A semi-cured thermosetting resin layer is formed on the surface of an adherend by a reaction. As the thermosetting resin composition containing the acrylic resin and the blocked isocyanate as the main components, the acrylic resin is applied by applying the resin liquid to the adherend and then heating it to the reaction temperature of the blocked isocyanate. And a part of the blocked isocyanate are reacted with each other to form a semi-cured thermosetting resin layer. As a thermosetting resin composition containing a cross-linking agent, a resin solution is applied to an adherend within a pot life, and then a semi-cured thermosetting resin layer is formed by a reaction between the cross-linking agent and an acrylic resin. Form.

In such a coating, since the thermosetting resin layer is in a semi-cured state and not completely cured, even if the coating is largely processed (bending or drawing), the thermosetting resin layer is not covered. The deformation of the adhered body is satisfactorily followed, and the film thickness of the thermosetting resin layer is not significantly reduced so that the flatness of the surface is not degraded. Then, after the coated product is processed into a desired shape, the coated product is heated to the reaction temperature of the blocked isocyanate to react the functional group of the acrylic resin with the isocyanate group of the blocked isocyanate, and an article having a strong coating film. Can be obtained.

The acrylic resin used in the present invention (hereinafter referred to as a reactive acrylic resin) is an acrylic polymer having at least two kinds of a hydroxyl group, a primary amino group and a carboxyl group, and is a solid polymer at room temperature. Is. Such a reactive acrylic resin includes, for example, a (meth) acrylic acid ester monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate, and 2-aminoethyl (meth) acrylate. At least different from the (meth) acrylic acid ester monomer having an amino group such as 3-aminopropyl (meth) acrylate and the (meth) acrylic acid having a carboxyl group such as (meth) acrylic acid. Copolymerize monomer materials selected from combinations of functional groups with other (meth) acrylic acid ester, styrene derivative monomers, maleic acid monomers, etc. using various peroxides and chain transfer agents as catalysts. Can be obtained.

Examples of the other (meth) acrylic acid ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, benzyl (meth) acrylate, and 2
-Ethoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate and the like can be mentioned.

Examples of the styrene derivative monomer include styrene and
α-methylstyrene, α-ethylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-ethoxystyrene, p-chlorostyrene, m-
Examples thereof include chlorostyrene and o-chlorostyrene.

The weight average molecular weight (Mw) of the reactive acrylic resin can be changed depending on the conditions when carrying out the polymerization reaction using an initiator, and the reactive acrylic resin used in the present invention has a weight average molecular weight of Those in the range of 100,000 to 1,000,000 are selected. When the weight average molecular weight is less than 100,000, it becomes difficult to maintain the sheet shape of the obtained covering sheet, sufficient elongation cannot be obtained by stretching during the sticking operation, and cracks may occur in some cases. On the other hand, when the weight average molecular weight exceeds 1,000,000, the resin composition mixed with the blocked isocyanate or the like has poor moldability, and it becomes difficult to prepare a coating sheet. For example, when a sheet is formed by solvent casting, the viscosity of the solvent becomes high, the resin can be cast only at a low concentration, and it becomes difficult to increase the film thickness of the sheet. In addition, Tg (glass transition point) and functional group value (sum of OH value, NH ₂ and COOH value) of these reactive acrylic resins
The preferable range of is preferably determined by the surface hardness after curing of the obtained covering sheet. For example, when the surface hardness after curing of the sheet is B or more (23 ° C.) by the pencil hardness method, Tg is Those having a functional group value of 20 to 200 in the range of -20 to 80 ° C are preferable. However, when the surface hardness of the sheet after curing is not so high, for example, when it is 2B or less (23 ° C.) by the pencil hardness method, it is applicable even if it is out of these ranges. The NH ₂ value is calculated by calculating the amount of NH ₂ groups added during polymerization in the same way as the OH value, or by reacting the NH ₂ groups with nitrous acid and converting them into OH groups, and the COOH value is added during polymerization. Do
Calculate the amount of COOH groups in the same way as the OH value, or calculate the COOH groups by KOH
It is the value titrated by.

The reactive acrylic resin can also be used as a copolymer obtained by block- or graft-polymerizing a low-molecular weight reactive acrylic resin and another polymer or monomer.
As other polymers or monomers, not only acrylic-based materials but also styrene-based, malein-based, imide-based, etc. materials having good compatibility with acrylic-based materials, as well as silicone-based and fluorine-based materials, etc. May be used in combination. In this case, the weight average molecular weight of the obtained copolymer may be within the above range, or the copolymer may be mixed with the above-mentioned reactive acrylic resin to adjust the weight average molecular weight of the mixture within the above range. Good. In the latter case, in particular, various adherends, for example,
It is advantageous for controlling the adhesive force to the surface of a polymer material such as a melamine resin, an epoxy resin, a phenol resin, a polycarbonate, an acetal resin, or a polyolefin.

The blocked isocyanate is mainly used as a heat-reactive curing agent for curing the reactive acrylic resin. Here, the blocked isocyanate is 2 in the molecule.
It means a compound obtained by blocking (masking) the isocyanate group of an isocyanate compound having one or more isocyanate groups with a blocking agent such as phenol, oxime, ε-caprolactam, malonic acid ester and the like. Examples of the above-mentioned isocyanate compound include monomers such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate, or trimethylolpropane adducts thereof, isocyanurate modified products, carbodiimide modified products and the like. In the blocked isocyanate, the blocking agent is released by heating, and the resulting isocyanate group causes a crosslinking reaction with the functional group of the reactive acrylic resin. The content of the blocked isocyanate is a ratio (functional group value / NCO value) of the number of functional groups of the reactive acrylic resin and the number of isocyanate groups contained in the blocked isocyanate to 0.
It is preferably adjusted to be in the range of 5 to 2.0, more preferably 0.8 to 1.2.

The unblocked isocyanate 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 such as thiophosphite, P-phenylene diisocyanate, xylylene diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate , Or of these monomers Trimethylolpropane adduct, an isocyanurate modified product, biuret modified products, carbodiimide-modified compounds, urethane modified product, an allophanate modified product, and the like.

The amount of the isocyanate added varies depending on the sheet forming method, but is preferably such that the NCO of the reactive acrylic resin is such that the functional group value: NCO = 1: 0.01 to 0.9.

The melamine-based crosslinking agent, including melamine, urea, thiourea, guanidine, guanamine, acetoguanamine,
Benzoguanamine, dicyandiamide and other materials having a polyfunctional amino group are reacted with formaldehyde and trimethylol melamine, hexamethylol melamine, dimethylol urea, dimethylol guanidine, dimethylol acetoguanidine, dimethylol benzoguandin butyl alcohol or It is an etherified melamine resin reacted with an alcohol such as propyl alcohol.
The addition amount of these melamine-based cross-linking agents does not have a fixed value with respect to the functional group of the reactive acrylic resin like isocyanate, and when adding, it is preferable to determine the addition amount by performing a preliminary experiment before making a sheet. However, for example, the functional group of the reactive acrylic resin is: OR (ether value) =
An amount of 1: 0.1 to 1.2 is preferable.

The epoxy-based cross-linking agent is a polyhydric alcohol glycidyl compound, and is used together with a Lewis acid catalyst. For example, diglycidyl ester of butadiene dioxide, hexazine dioxide and phthalic acid, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, triglycidyl ether amine of paraaminophenol, diglycidyl ether of aniline, tetraglycidyl of phenylenediamine. Examples thereof include glycidyl compounds such as ether, sulfonamide diglycidyl ether, glycerin triglycidyl ether, polyether-modified diglycidyl, polyester-modified diglycidyl, and urethane-modified diglycidyl compound (polymer).

The amount of the epoxy-based crosslinking agent added is based on the functional group value.
Functional group: CH ₂ CH ₂ O (epoxy group) = 0: 0.01 to 0.9 is preferable. Further, since this epoxy cross-linking agent reacts with a functional group to generate an OH group, the amount of the blocked isocyanate added at the same time is 3 to the equivalent of the remaining hydroxyl group of the functional group of the reactive acrylic resin and the generated hydroxyl group. It is preferable to add a combined amount of about 80%.

The addition amount of the above-mentioned cross-linking agent is preferably in the above-mentioned range, but actually the reaction of the cross-linking agents depending on the reactivity of the reactive acrylic resin used, for example, the reaction between the melamine-based cross-linking agent and the epoxy-based cross-linking agent, Since the reaction between these reactants and the functional group of the reactive acrylic resin occurs, it is preferable to determine the actual addition amount after conducting a preliminary experiment.

If necessary, a reactive acrylic oligomer containing a hydroxyl group, an amino group or a carboxyl group may be added to the thermosetting resin composition of the present invention to impart further spreadability and flexibility to the adherend. can do.

The reactive acrylic oligomer is an acrylic oligomer having at least one kind of a functional group of a hydroxyl group, an amino group and a carboxyl group like the above-mentioned reactive acrylic resin, and is a solid or solid solution polymer at room temperature. . Such a reactive acrylic oligomer can be obtained, for example, by the following method.

(Meth) acrylic acid ester monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate
Reaction with acrylic ester monomers.

(Meth) acrylic acid ester monomer and an amino group having an amino group such as 2-aminoethyl (meth) acrylate, 4-aminobutyl (meth) acrylate, etc.
Reaction with acrylic ester monomers.

Reaction of a (meth) acrylic acid ester monomer with a (meth) acrylic acid ester monomer having a carboxyl group such as (meth) acrylic acid.

Each of the above reactions can be obtained by copolymerization in the same manner as the above-mentioned reactive acrylic resin, but in this case, a chain transfer agent is added in a much larger amount than in the case of the above-mentioned reactive acrylic resin and polymerized. A reactive acrylic oligomer having a weight average molecular weight of 1,000 to 10,000 is preferably used. Weight average molecular weight of reactive acrylic oligomer is 1,00
When it is less than 0, the moldability of the obtained resin composition is poor and the handling of the coating sheet becomes difficult. The weight average molecular weight is
If it exceeds 10,000, the resulting sheet lacks flexibility and is inferior in moldability. Further, this reactive acrylic oligomer has a glass transition point of -50 ° C to 40 ° C within the range of -50 ° C to 40 ° C due to the relationship between the moldability of the sheet and the hardness of the cured film.
The total sum of ₂ and COOH value) is preferably in the range of 40 to 250.
The amount of the reactive acrylic oligomer added is preferably about 10 to 200 parts by weight based on 100 parts by weight of the solid content of the reactive acrylic resin. In addition, the reactive acrylic oligomer may be used in combination with a plurality of types of reactive acrylic oligomers as long as they are within these molecular weight ranges.

Further, the thermosetting resin composition may contain a coloring agent such as a pigment or a dye. As the colorant, pigments and dyes used in ordinary paints can be used. For example, pigments include titanium oxide, iron oxide, carbon black, cyanine-based pigments, quinacridone-based pigments, etc., and dyes include azo-based dyes, anthraquinone-based dyes, indigoid-based dyes, stilbene-based dyes, etc., and aluminum flakes, You may use metal powders, such as nickel powder, gold powder, and silver powder, as a coloring agent. When a colorant having a high hiding power is used, the total amount of the colorant is preferably in the range of 2 to 100 parts with respect to 100 parts by weight of the resin solid content (hereinafter referred to as “parts”). Further, the thermosetting resin composition may further contain an inorganic filler, a metal material or the like in order to adjust the surface condition, or may contain a known antiaging agent, rust preventive agent or the like. Good.

A thermosetting resin composition is obtained by mixing the above components, and the resin composition forms the thermosetting coating sheet of the present invention. The covering sheet may be manufactured by any method,
For example, the above-mentioned materials are sufficiently dissolved and stirred in an organic solvent, and then processed paper by a casting method such as comma roll or comma reverse (usually polyethylene terephthalate film (PET film) or paper release-treated with silicone) It can be obtained by coating the above and performing drying for removing the solvent.

The thermosetting coating sheet of the present invention is thus a sheet in an uncured state in which the functional groups of the acrylic resin contained in the composition are not reacted, or a semi-cured state in which a part of them is reacted. It can be used as a sheet.
When it is used as a semi-cured sheet, it can be heated by heating to the reaction temperature of the blocked isocyanate for a predetermined time as described above, or by adding the crosslinking agent.

In the semi-cured sheet, the functional group of the acrylic resin contained in the sheet is preferably such that 0.01% to 80% of the total number of functional groups of the acrylic resin before the reaction is reacted. That is, the reaction rate (initial curing rate) of this functional group varies depending on the method of using the sheet. For example, if the adherend to be pasted has convex or vertical parts or if the work of attaching the sheet is at a considerably high temperature (30 ° C or higher), the sheet forming temperature
It is preferable to crosslink 0.01 to 40%, more preferably 1 to 30% of the functional groups with an isocyanate so as to obtain an elongation of 100% or more. When the covering sheet is used in a place where high pressure acts on the sheet such as press molding or insert injection, 20-80% of functional groups are reacted so as to withstand molding temperature and resin pressure. Good to use. The value of the reaction rate of these functional groups may change to some extent depending on the molding temperature.

The film thickness of the thermosetting coating sheet of the present invention varies depending on the stickability of the sheet to an adherend and the addition of a function to the adherend,
Considering the case of sticking to an uneven adherend surface, 20
~ 500μm is preferable, but it is 5 for sticking on a flat surface.
It may be about 1,000 μm.

Further, the thermosetting coating sheet of the present invention may be laminated with other layers for imparting various functions. For example,
When the viscosity of the thermosetting resin composition at room temperature is low, it becomes difficult for the thermosetting coating sheet to retain its shape. In such a case, the shape retention of the covering sheet can be improved by providing a supporting layer on the covering sheet. This support layer is used for maintaining the shape of the entire sheet, but it is preferable to impart flexibility to the support layer when the sheet is attached to a three-dimensional curved surface or the like while the support layers are laminated. .

For example, the support layer can be formed of an elastic material such as rubber or a thermoplastic or thermosetting material that exhibits malleability when heated. These supporting layers may be peeled off and cured immediately after the sheet is applied to the adherend, and after the covering sheet is adhered and cured, until the use of these adherends. It may be used as a protective layer in between. Furthermore, the surface shape (surface state) of the thermosetting coating sheet can be adjusted by embossing or patterning the surface of the support layer.

When the coating sheet does not have sufficient adhesive force to the adherend to be coated, an adhesive layer is laminated on the back surface of the sheet, and the surface of the adherend is coated via this adhesive layer. Sheet may be attached. As the adhesive layer, for example, EVA hot melt adhesive, SIS hot melt adhesive, acrylic hot melt adhesive, unsaturated polyester uncrosslinked material, acrylic adhesive, silicone adhesive, post-curing Acrylic adhesives and the like can be used, and blends or laminates of these can also be used.

When the surface of the adherend is hydrophilic, the above-mentioned coating sheet is directly attached to the adherend, or an adhesive layer is used, and the surface of the adherend is lipophilic. It is preferable to directly apply a covering sheet to the. When the surface of the adherend is water-repellent and oil-repellent, it is preferable to use a coating sheet laminated with a silicone adhesive layer. Regarding the adhesion to these adherends, by using a block or graft copolymer acrylic resin for the thermosetting coating sheet, or by using a coating sheet having an adhesive layer according to the adherend. It can be attached to various adherends without any trouble.

Furthermore, since the covering sheet of the present invention is mainly used in place of painting, a clear layer may be provided on the surface of the sheet. As the clear layer, a transparent resin composition, for example, a resin composition used in the present invention,
A layer of a resin composition containing no colorant may be provided, or a sheet material having excellent transparency such as an acrylic resin, a fluorine resin, a urethane resin, or a vinyl chloride resin may be used.

The thermosetting coating sheet of the present invention is to obtain an article by being attached to a workable adherend such as a steel plate in an uncured or semi-cured state, processed into an appropriate shape, or heat-cured as it is. .

Various methods can be used for the attachment to the adherend. For example, a hand pasting method, a laminator method, a (vacuum) press, an insert injection, a vacuum contact molding method (vacuum packaging molding), etc. can be adopted. In order to particularly improve the adhesion to the adherend and to improve the rust preventive property, vacuum adhesion molding or vacuum pressing in which a vacuum is applied between the adherend and the thermosetting coating sheet is preferable. The heating conditions for the thermosetting coating sheet are appropriately set depending on the reaction temperature of the blocked isocyanate used, the amount of the reactive and reactive acrylic resin, the crosslinking agent, and the like, the reactivity, and the like.

Next, the coating material of the present invention will be described in detail.

The thermosetting resin composition used for the coating of the present invention can be used the material used for the above-mentioned thermosetting coating sheet, a resin solution obtained by dissolving or dispersing the thermosetting resin composition in a solvent. It is applied to an adherend and dried to form a semi-cured thermosetting resin layer on the surface of the adherend.

Here, the semi-cured state is preferably a state in which 5% to 80% of the total number of functional groups of the acrylic resin before reaction contained in the thermosetting resin layer has reacted. If the reaction rate is lower than 5%, the thermosetting resin layer will flow out against the pressure during the secondary processing, or the molding process will be difficult. If the reaction rate exceeds 80%, the thermosetting resin layer will be hard. When the secondary processing is performed, the thermosetting resin layer is cracked or peeled off. Therefore,
The functional group of the acrylic resin contained in the thermosetting resin layer is 5
% To 80% is preferable, and more preferably 7 to 75%.

The thickness of the thermosetting resin layer is preferably about 5 to 1,000 μm, and 20 μm to 500 μm when the coating is processed to a large size.
Is preferable, and 30 μm to 100 μm is more preferable.

In the coating provided with a thermosetting resin layer using a resin solution containing no crosslinking agent described above, the reaction conditions for the initial curing of the reactive acrylic resin and the blocked isocyanate are the same as in the case of the coating sheet. The reaction temperature is determined by the blocking agent of the blocked isocyanate, and the reaction time is determined by the functional group value of the reactive acrylic resin, the addition amount of the blocked isocyanate, and their reactivity. For example, when methyl ethyl ketone oxime block (isophorone diisocyanate: non-catalyst state) is used as the blocked isocyanate, if the NCO value is 1: 1 with respect to the reactive acrylic resin (functional group value 80), it will be 2 %, 18% in 5 minutes, 40% in 10 minutes, 80% in 18 minutes, and 100% in 30 minutes.

In this method of confirming the reaction status, the functional group value can be quantified by the IR (infrared spectroscopy) absorption coefficient of the thermosetting resin layer in each state.

The preferable reaction time for these initial curings is related to the reaction temperature of the blocked isocyanate used (desorption temperature of the blocking agent) and the reaction completion time. The relationship is slightly different depending on the blocking agent, but is as shown in Table 1.

However, in these reactions, in addition to the reaction between the isocyanate and the functional group of the reactive acrylic resin, the reaction between the isocyanate and the isocyanate via water occurs, so that the reaction time depends on the curing environment (for example, temperature and humidity). It can be different. Further, a curing accelerating catalyst may be added to improve the reactivity of the blocked isocyanate, and in this case as well, the reaction rate may be slightly changed.

The coating can be produced by ordinary coating and drying. For example, a resin solution is evenly applied to the surface of an adherend by solvent coating with a spray gun or coating such as casting, and then the coating film is dried by hot air or infrared radiant heat in a drying zone (dryer). A thermosetting resin layer is formed. Here, in order to reduce the distribution of the curing rate with respect to the thickness of the coating material, it is preferable that the heating is performed uniformly on the entire coating film on the surface of the adherend.

Various adherends can be used as the adherend used in the present invention. For example, metal plates such as steel plates and aluminum plates,
Metal plating plates such as galvanized iron and tin plate, ceramics such as wood, gypsum board, cement and crockery, steel plates, ceramics, coated plates with resin film laminated on resin material, and also polyolefin, ABS resin, polyphenylene sulfide It is a material such as a thermoplastic resin such as (PPS) or polyetherimide, or a thermosetting resin such as a melamine resin, an epoxy resin, a phenol resin, or a polyimide.

Further, the surface of the adherend may be subjected to various surface treatments.
For example, there are various acid treatments such as phosphoric acid that are usually performed on steel sheets, alkali treatments, various surface treatments such as solvent treatment, corona discharge treatment, glow discharge treatment, plasma treatment, and ion implantation on the resin surface, and primer treatment. .

(Example) Hereinafter, the present invention will be described in detail based on examples.

The physical properties of the coated material were measured as follows.

(A) Adhesion: Put 100 cuts with a 1 mm interval on the surface of the coating in a grid pattern and attach a commercially available adhesive tape to this.
Then, the tape was peeled off and the residual rate of the cross-cut pieces was evaluated.

(B) Hardness: It was evaluated by a pencil hardness test according to JIS K5400.

(C) Appearance: The radius of curvature is obtained by placing the coating on a right-angled triangle die with the 90 ° vertex on top and pressing it.
It was bent 90 ° at 5 mm, and the appearance of the corners (generation of cracks and cracks and the thickness uniformity of the coating) was visually observed.

(D) Anticorrosion property: Performed according to a salt spray test (JIS Z 2370).

Example 1 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, weight average molecular weight 565,000, Tg 35 ° C., COOH value 2).
0 and NH ₂ value 40) to 100 parts by solid content, blocked isocyanate (Takeda Yakuhin Kogyo Co., Takenate B-815N, ketoxime block, NCO7.3%) 37 parts by solid content (this blocked isocyanate is 1.0 equivalent of isocyanate group with respect to the functional group of the reactive acrylic resin was mixed under good stirring. This resin solution was applied to the release surface of a polyethylene release-treated polyethylene terephthalate film (manufactured by Soken Kako Co., Ltd., film thickness 40 μm, hereinafter PET film) with an applicator and dried at 80 ° C. for 5 minutes. To obtain a thermosetting coating sheet. Sheet thickness is 80 μm
Met.

Next, the above sheet was subjected to acrylic melamine coating by vacuum adhesion molding (vacuum packaging molding) into a hemisphere with a radius of 15 cm at 50 ° C.
Then, when the ultimate vacuum reached 10 Torr, it was attached and then heat-cured at 160 ° C. for 30 minutes to obtain a coating. The pencil hardness of the obtained coating is H, and the adhesion is 1 mm wide in a cross-cut test.
It was 00/100.

Example 2 300 parts of ethyl acetate was added to a reactive acrylic resin (copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and ethyl acrylate, weight average molecular weight 250,000, Tg15).
℃, OH value 40 and COOH value 40) to 100 parts by solid content, blocked isocyanate (Takenate B-815 manufactured by Takeda Pharmaceutical Co., Ltd.)
N, ketoxime block, NCO 7.3%) 59 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin) were mixed with good stirring. PET this resin solution
The release surface of the film was coated with an applicator and dried at 80 ° C for 5 minutes to obtain a thermosetting coating sheet. The film thickness of the sheet was 200 μm.

Next, by vacuum contact molding, the above-mentioned sheet with a radius of 10 cm and height
It was attached to a dish of 6 cm and a radius of 6 cm at the bottom at 100 ° C when the ultimate vacuum reached 6 Torr, and then heat-cured at 160 ° C for 30 minutes to obtain a coating. The resulting coating had a pencil hardness of HB and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 3 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and 4-aminobutyl methacrylate, a weight average molecular weight of 36).
8,000, Tg10 ℃, OH value 40 and NH ₂ value 40) to 100 parts by solid content, block acrylic polycarboxylic acid (copolymer of stearyl methacrylate and methacrylic acid, weight average molecular weight
25,000, Tg20 ℃, COOH value 20) 10 parts by solid content, Blocked isocyanate (Nippon Polyurethane Industry Co., Coronate)
2513, ethyl acetoacetate block, NCO 10.2%) 48 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the total functional groups of the above-mentioned reactive acrylic resin and blocked acrylic polycarboxylic acid) Mix with good stirring. This resin solution was applied to the release surface of the PET film with an applicator and dried at 70 ° C for 10 minutes to obtain a thermosetting coating sheet. Sheet thickness is 100
was μm.

Next, by vacuum contact molding, the above sheet was attached to a polypropylene hemisphere with a radius of 15 cm at 60 ° C when the ultimate vacuum reached 5 Torr, and then at 120 ° C for 2 minutes and then 100 ° C.
The coating was obtained by heating and curing for 1 hour. The obtained coating had a pencil hardness of B and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 4 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate, acrylic acid and 4-aminoethyl methacrylate, weight average molecular weight of 360,000, Tg of 35 ° C., OH value). 20 and COOH value 20 and NH ₂
40) to 100 parts by solids, blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO 7.3%) 59 parts by solids (this blocked isocyanate is the above reactive acrylic resin). (Having 1.2 equivalents of isocyanate groups with respect to the functional groups of 1.) were mixed with good stirring. This resin solution was applied to the release surface of the PET film with an applicator, dried at 80 ° C for 5 minutes, and further heated at 160 ° C for 5 minutes to obtain a thermosetting coating sheet. Infrared absorption (IR) analysis of the reaction rate of this coating sheet
25% of the total functional groups had reacted, as determined by quantifying the sensitive groups of. The film thickness of the sheet was 50 μm.

Next, the sheet was fixed to the inner peripheral surface of a cylindrical cavity having a radius of 10 cm and a height of 6 cm formed in an injection mold, and a polyetherimide resin was injected. Then 16
A coating was obtained by heat curing at 0 ° C. for 20 minutes. The resulting coating has a pencil hardness of 2H and an adhesion of 100/1 in a 1mm width cross-cut test.
It was 00.

Example 5 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, methacrylic acid and 3-aminopropyl acrylate, weight average molecular weight 621,000, Tg 10 ° C, COO).
H value 40 and NH ₂ value 40) in 100 parts by solid content, acrylic polyamine oligomer (butyl acrylate and methacrylic acid 2-
Aminoethyl copolymer, weight average molecular weight 4,000, Tg-3
50 ° C., NH ₂ value 150) in solid content, blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO7.3%) 115 parts in solid content (the blocked isocyanate is The reactive acrylic resin and the acrylic polyamine oligomer have 1.2 equivalents of isocyanate groups based on the total functional groups), and 40 parts of titanium oxide were mixed while stirring well. This resin solution was applied to the release surface of the PET film with an applicator and dried at 80 ° C for 5 minutes to obtain a thermosetting coating sheet. Sheet thickness is 150μ
It was m.

Next, the above-mentioned sheet was heated to 100 ° C. by vacuum contact molding, and a rectangular parallelepiped made of stainless steel SUS-304 having a length and width of 15 cm and a height of 10 cm was attached at a time when the reached vacuum degree at 80 ° C. reached 6 Torr, and then, A coating was obtained by heat curing at 160 ° C. for 30 minutes. The obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 6 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, methacrylic acid and 2-aminoethyl acrylate, weight average molecular weight 565,000, Tg 35 ° C., COOH).
Valency 20 and NH ₂ valency 40) in 100 parts by solid content, acrylic polycarboxylic acid oligomer (copolymer of ethyl acrylate and methacrylic acid, weight average molecular weight 5,000, Tg-20 ° C, COOH value 5
0) solids 20 parts, blocked isocyanate (Nippon Polyurethane Industry Co., Ltd., 2525 Coronate, ethyl acetoacetate block, NCO 10.2%) solids 41 parts (this blocked isocyanate is the above-mentioned reactive acrylic resin and acrylic polycarboxylic 2 parts by weight of zinc chromate were mixed while stirring well, with 1.0 equivalent of isocyanate groups based on the total functional groups of the acid oligomer). This resin solution was applied to the release surface of the PET film with an applicator and dried at 70 ° C for 10 minutes to obtain a thermosetting coating sheet. Sheet thickness is 80 μm
Met.

Next, the above-mentioned sheet was heated to 100 ° C. by vacuum adhesion forming, and a vacuum degree of 6 Torr reached at 80 ° C. on a cube made of steel plate SS-41 (diluted nitric acid treatment-washed with ion-exchanged water) with a side of 10 cm.
When it reached r, it was pasted and then heat-cured at 120 ° C. for 20 minutes to obtain a coating. The obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test. Furthermore, when the rust prevention was evaluated, no rust was found even after 200 hours.

Example 7 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, methacrylic acid and 2-aminoethyl acrylate, weight average molecular weight 492,000, Tg 35 ° C., COOH).
Valency 40 and NH ₂ valency 40) to 100 parts by solid content, blocked isocyanate (Takeda Chemical Industries, Takenate B-870N, ketoxime block, NCO 12.6%) 23 parts by solid content (this blocked isocyanate is With respect to the functional group of the reactive acrylic resin, it has an isocyanate group of 0.8 equivalent),
Epoxy cross-linking agent (Ciba Geigy, Araldide CY17
5, epoxy equivalent 160, epoxy value corresponding to functional group value
220) 4.9 parts (amount in which 10% of the functional groups of the reactive acrylic resin react) were mixed with good stirring. This resin liquid is PE
The release surface of the T film was coated with an applicator and dried at 80 ° C for 5 minutes to obtain a thermosetting coating sheet. The film thickness of the sheet was 80 μm.

Next, the above-mentioned sheet was subjected to alkyd melamine coating treatment by vacuum adhesion molding at a temperature of 60 ° C. on a hemisphere with a radius of 10 cm and the ultimate vacuum was
When it reached 6 Torr, it was attached and then heat-cured at 160 ° C. for 30 minutes to obtain a coating. The obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 8 300 parts of ethyl acetate was added to a reactive acrylic resin (copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and acrylic acid, weight average molecular weight 250,000, Tg 15 ° C., OH).
Value 40 and COOH value 40) to 100 parts by solid content, blocked isocyanate (Takenate Beverage Co., Takenate B-815N, ketoxime block, NCO7.3%) 59 parts by solid content (this blocked isocyanate is the above It has 1.2 equivalents of isocyanate groups with respect to the functional groups of the reactive acrylic resin),
Isocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L, NCO 13.0%) was mixed with 10 parts of solid content (the amount by which 30% of the functional groups of the reactive acrylic resin reacts) with good stirring. This resin solution was applied to the release surface of the PET film with an applicator and dried at 80 ° C for 5 minutes to obtain a thermosetting coating sheet. The film thickness of the sheet was 200 μm.

Next, using a vacuum press (a dish-shaped mold), the above sheet was attached to a steel plate (SS41) dish with a radius of 15 cm, a height of 8 cm, and a bottom radius of 10 cm at 110 ° C, and then at 160 ° C for 30 minutes. The coating was obtained by heating and curing. The pencil hardness of the obtained coating is H,
Adhesion was 100/100 in a 1 mm width cross-cut test.

Example 9 300 parts of ethyl acetate was added to a reactive acrylic resin (copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and 4-aminobutyl methacrylate, weight average molecular weight 36
8,000, Tg10 ° C, OH value 40 and NH ₂ value 40) in 100 parts by solid content, block reactive acrylic resin (copolymer of methyl methacrylate and 2-hydroxyethyl methacrylate), weight average molecular weight 36,000, Tg40 ℃, OH value 40) as solid content 10
Part, blocked isocyanate (Nippon Polyurethane Industry, Coronate 2513, ethyl acetoacetate block, NCO1
0.2%) 49 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the total functional groups of the reactive acrylic resin and the block reactive acrylic resin), isocyanate (Nippon Polyurethane Industry, Coronate L, NCO 13.0%), and 3.6 parts (the amount by which 10% of the total functional groups of the above-mentioned reactive acrylic resin and block reactive acrylic resin react) in solid content was mixed with good stirring. This resin solution was applied to the release surface of the PET film with an applicator and dried at 70 ° C for 10 minutes to obtain a thermosetting coating sheet. The film thickness of the sheet was 100 μm.

Next, by vacuum contact molding, the above sheet was attached to a polypropylene hemisphere with a radius of 12 cm at 60 ° C when the ultimate vacuum reached 10 Torr, and then heat cured at 120 ° C for 2 minutes and further at 100 ° C for 1 hour. A coating was obtained. The obtained coating had a pencil hardness of B and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 10 300 parts of ethyl acetate was added to a reactive acrylic resin (copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate, acrylic acid and 4-aminoethyl methacrylate, weight average molecular weight of 480,000, Tg of 35 ° C., OH value of 20 and COOH value 20 and NH ₂
40) to 100 parts by solids, blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO 7.3%) 39 parts by solids (this blocked isocyanate is the above-mentioned reactive acrylic resin). With 0.8 equivalent of isocyanate group) and a melamine-based cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Beckamine (butylated melamine resin) J-820-60) with a solid content of 56 parts (reactivity). 60% of the functional groups of the acrylic resin reacted) were mixed with good stirring. This resin solution was applied to the release surface of the PET film with an applicator and dried at 80 ° C for 5 minutes to obtain a thermosetting coating sheet. Sheet thickness is 60
was μm.

Next, this sheet was treated in the same manner as in Example 4 with the cavity of an injection mold (a tubular shape having a radius of 10 cm and a height of 3 cm).
It was fixed to the inner peripheral surface of and the polyetherimide resin was injected. Then, it was heated and cured at 160 ° C. for 20 minutes to obtain a coating. The resulting coating had a pencil hardness of HB and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 11 To 300 parts of ethyl acetate, a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 3-aminopropyl acrylate, weight average molecular weight 621,000, Tg 10 ° C., COOH
Valence 40 and NH ₂ valence 40) to 100 parts by solid content, acrylic polycarboxylic acid oligomer (copolymer of ethyl acrylate and acrylic acid, weight average molecular weight 25,000, Tg-30 ° C, COOH value 10
0) 20 parts by solid content, blocked isocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate 2513, ethyl acetoacetate block, NCO 10.2%) 59 parts by solid content (this blocked isocyanate is the above-mentioned reactive acrylic resin and acrylic polycarboxylic acid). For the functional group including the acid oligomer, 1.
Has 0 equivalents of isocyanate group), isocyanate (Nippon Polyurethane Industry, Coronate L, NCO13.0
%) In solid content (amount in which 10% of the above functional groups reacts) and 2.5 parts of zinc chromate were mixed with good stirring. This resin solution was applied to the release surface of the PET film with an applicator and dried at 70 ° C for 10 minutes to obtain a thermosetting coating sheet. The film thickness of the sheet was 80 μm.

Next, the above sheet was attached to a cube by vacuum contact molding in the same manner as in Example 6, and then heat-cured at 120 ° C. for 20 minutes to obtain a coating. The obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test. Furthermore, when the rust prevention was evaluated, no rust was found even after 200 hours.

Example 12 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, methacrylic acid and 2-aminoethyl acrylate, weight average molecular weight 250,000, Tg 30 ° C., COOH).
Valency 30 and NH ₂ valency 30) to 100 parts by solids, blocked isocyanate (Takeda Chemical Industries, Takenate B-815N, ketoxime block, NCO 7.3%) 37 parts by solids (this blocked isocyanate is 1.0 equivalent of isocyanate group with respect to the functional group of the above-mentioned reactive acrylic resin) was mixed while stirring well. This resin solution is applied to a steel plate (SS-41,
2mm thick, diluted nitric acid treatment-washed with ion-exchanged water), spray coated to a thickness of 60μm, dried at 60 ° C for 20 minutes, then heat-cured at 160 ° C for 10 minutes to form a coating. Obtained. The reaction rate of the obtained coating was 40% by IR measurement.

Example 13 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and 2-aminoethyl acrylate, a weight average molecular weight of 560,
000, Tg20 ℃, OH value 40 and NH ₂ value 40) to 100 parts by solid content,
Blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO7.3%, ethyl acetate solvent) 49 parts by solids (this blocked isocyanate is 1.0% relative to the functional group of the reactive acrylic resin). 60 parts of titanium oxide were mixed with good stirring. This resin solution was spray-coated on the same steel plate as in Example 12 so that the film thickness was 50 μm, and the temperature was 60 ° C.
And dried at 160 ° C. for 3 minutes to obtain a coating. The reaction rate of the coating was 10% by IR measurement.

Example 14 300 parts of ethyl acetate, a reactive acrylic resin (copolymer of methyl methacrylate and 3-hydroxypropyl methacrylate and methacrylic acid, weight average molecular weight 450,000, Tg 0 ℃,
OH value 40 and COOH value 80) to 100 parts by solids, block acrylic polyamine (copolymer of stearyl methacrylate and 2-aminoethyl methacrylate, weight average molecular weight 25,0
00, Tg20 ° C, NH ₂ value 20), 10 parts by solid content, blocked isocyanate (Nippon Polyurethane Industry, Coronate 251)
3, ethyl acetoacetate block, NCO 10.2%) solid content 71
Parts (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin and the amino groups of the blocked acrylic polyamine) were thoroughly mixed. This resin solution was applied to a steel plate similar to that used in Example 12 so that the film thickness was 20 μm, dried at 60 ° C. for 20 minutes, and then heat-cured at 120 ° C. for 10 minutes to obtain a coated product. The reaction rate of the obtained coating was 70% by IR measurement. Example 15 300 parts of ethyl acetate was added to a reactive acrylic resin (2-hydroxyethyl methacrylate, methacrylic acid, 2-aminoethyl methacrylate and methacrylic acid). Butyl copolymer, weight average molecular weight 163,000, Tg-10 ℃, OH number 30 and COOH number 20 and N
H ₂ value 30) to 100 parts by solids, blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO 7.3%) 49 parts by solids (this blocked isocyanate has the above-mentioned reactivity) 60 parts of titanium oxide and 1.0 equivalent of isocyanate groups with respect to the functional groups of the acrylic resin were mixed with good stirring. This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness was 50 μm, dried at 60 ° C. for 20 minutes, and then heat-cured at 160 ° C. for 15 minutes to obtain a coating. The reaction rate of the obtained coating is IR
It was 72% as measured.

Example 16 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and 2-aminoethyl acrylate, a weight average molecular weight of 560,
000, Tg20 ℃, OH value 40 and NH ₂ value 40) to 100 parts by solid content,
Block isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NCO 12.6%) 20 parts by solid content (this block isocyanate is 0.7 equivalent of isocyanate group based on the functional group of the reactive acrylic resin) And a melamine-based cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Beckamine (isobutylated melamine resin) J-821-60) with solid content of 26 parts (amount in which 40% of the functional groups react) are well stirred. While mixing.

This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness would be 40 μm, and dried at 70 ° C. for 20 minutes.
A coating was obtained by heating at 120 ° C for 10 minutes.

Example 17 300 parts of ethyl acetate was mixed with a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, a weight average molecular weight of 250,000, a Tg of 30 ° C. and a COOH value of 5).
0 and NH ₂ value 50) to 100 parts by solid content, blocked isocyanate (Takenate B-815N, NCO7.3 manufactured by Takeda Pharmaceutical Co., Ltd.)
%) 37 parts by solid content (this blocked isocyanate has 0.6 equivalent of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin), isocyanate (Nippon Polyurethane Industry Co., Coronate L, NCO 13.0%) solid 2 in a minute
2 parts (amount in which 50% of the functional groups of the reactive acrylic resin react) and 60 parts of titanium oxide were mixed while stirring well.

This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness was 35 μm, and dried at 60 ° C. for 20 minutes to obtain a coating.

Example 18 300 parts of ethyl acetate, a reactive acrylic resin (copolymer of methyl methacrylate and 3-hydroxypropyl methacrylate and methacrylic acid, weight average molecular weight 450,000, Tg 0 ℃,
OH value 40 and COOH value 80) to 100 parts by solid content, comb-shaped reactive acrylic resin (comb-shaped block copolymer of main chain stearyl methacrylate and side chain methacrylic acid, weight average molecular weight 105,
000, Tg 0 ° C, OH value 20) 10 parts by solid content, blocked isocyanate (Nippon Polyurethane Industry Co., Ltd., Coronate 2513,
NCO 10.2%) 43 parts by solids (this blocked isocyanate has 0.6 equivalent of isocyanate groups with respect to the functional groups of the reactive acrylic resin and the comb-shaped reactive acrylic resin), isocyanate (Nippon Polyurethane Industry, Coronate L, NCO 13.0%) was mixed in a solid content with 26 parts (the amount by which 50% of the functional groups of the reactive acrylic resin and the comb-shaped reactive acrylic resin react) with thorough stirring.

This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness would be 50 μm, and dried at 70 ° C. for 20 minutes to obtain a coating.

Example 19 To 300 parts of ethyl acetate, a reactive acrylic resin (copolymer of 2-hydroxyethyl methacrylate, methacrylic acid, 2-aminoethyl methacrylate and butyl methacrylate, weight average molecular weight 163,000, Tg-10 ° C, OH Value 30 and COOH value 20 and N
H ₂ value 30) in 100 parts by solid content, blocked isocyanate (Takeda Chemical Industries, Takenate B-815N, NCO 7.3%) 39 parts in solid content (this blocked isocyanate is a functional group of the above reactive acrylic resin) On the other hand, it has 0.8 equivalent of isocyanate group, epoxy type cross-linking agent (made by Ciba Geigy, Araldide CY175, epoxy equivalent 160, epoxy value 220 corresponding to functional group value) 18 parts (50 of the functional group of the reactive acrylic resin) %), And 60 parts of titanium oxide were mixed with good stirring. This resin solution was spray-coated on the same steel plate as in Example 12 so that the film thickness was 50 μm, and the temperature was 60 ° C.
And dried for 20 minutes to obtain a coating.

Comparative Example 1 In Example 1, as the reactive acrylic resin, a reactive acrylic resin having a weight average molecular weight of 32,000 (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, Tg 30 ° C., COOH value 40 and NH 3) was used. except for using the _bivalent 20), to obtain a coated sheet having a thickness of 100μm in the same manner as in example 1.

The obtained sheet was stuck to a hemisphere with a radius of 15 cm which had been subjected to acrylic melamine coating by vacuum adhesion molding in the same manner as in Example 1 at 80 ° C. and when the ultimate vacuum reached 6 Torr, the sheet broke and could not be molded. .

Comparative Example 2 In Example 2, as the reactive acrylic resin, a reactive acrylic resin having a weight average molecular weight of 63,000 (a copolymer of methyl methacrylate and 2-hydroxyethyl methacrylate and acrylic acid, Tg 15 ° C., OH value 40 and COOH) was used. A coating sheet having a film thickness of 200 μm was obtained in the same manner as in Example 2 except that the value of 40) was used.

The obtained sheet was stuck on a dish of Setomono at 100 ° C. when the ultimate vacuum reached 4 Torr by vacuum adhesion forming as in Example 2, and the sheet was broken and could not be formed.

Comparative Example 3 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, a weight average molecular weight of 32,000, a Tg of 30 ° C., a COOH value of 40).
And NH ₂ value 20) to 100 parts by solids, blocked isocyanate (Takeda Yakuhin Kogyo Co., Takenate B-815N, ketoxime block, NCO7.3%) 37 parts by solids Having an equivalent amount of isocyanate groups to the functional groups of the water-soluble acrylic resin), isocyanate (made by Nippon Polyurethane Industry, Coronate L, NC)
O13.0%) was mixed in a solid content of 2.6 parts (the amount by which 10% of the functional groups of the above-mentioned reactive acrylic resin react) with thorough stirring. This resin solution was applied and dried in the same manner as in Example 1 to obtain a thermosetting coating sheet. The film thickness of the sheet was 100 μm.

The obtained sheet was stuck to a hemisphere having a radius of 15 cm, which was subjected to alkyd melamine coating treatment by vacuum adhesion molding in the same manner as in Example 1, at 80 ° C. and when the ultimate vacuum reached 6 Torr, the sheet broke and could not be formed. .

Comparative Example 4 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl methacrylate and acrylic acid, a weight average molecular weight of 63,000, a Tg of 15 ° C., an OH value).
40 and COOH value 40) to 100 parts by solid content, blocked isocyanate (Takenate Kogyo Co., Ltd., Takenate B-815N, ketoxime block, NCO7.3%) 59 parts by solid content (this blocked isocyanate is the above reaction With an isocyanate group of 1.2 equivalents with respect to the functional group of the water-soluble acrylic resin),
Melamine type cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Beckamine (butylated melamine resin) J-820-60) 28 parts (amount that 30% of the functional groups of the reactive acrylic resin react) with solid content are well stirred While mixing. This resin solution was applied and dried in the same manner as in Example 1 to obtain a thermosetting coating sheet. The film thickness of the sheet was 200 μm.

The obtained sheet was stuck on a dish of Setomono by vacuum adhesion forming in the same manner as in Example 2 at 100 ° C. and when the ultimate vacuum reached 4 Torr, and the sheet broke and could not be formed.

Comparative Example 5 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, a weight average molecular weight of 78,000, a Tg of 25 ° C. and a COOH value of 40).
And NH ₂ value 20) to 100 parts by solids, blocked isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block, NCO7.3%) 37 parts by solids (Having 1.0 equivalent of isocyanate groups with respect to the functional groups of the water-soluble acrylic resin) was mixed with good stirring. This resin solution was spray-coated on a steel plate similar to that of Example 12 to a film thickness of 50 μm, and the coating was performed at 60 ° C.
The coating was obtained by drying for 20 minutes and then heat curing at 160 ° C. for 15 minutes. The reaction rate of the obtained coating is 70% by IR measurement
Met.

Comparative Example 6 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl acrylate and 2-aminoethyl acrylate, a weight average molecular weight of 153,00).
0, Tg35 ℃, OH value 40 and NH ₂ value 20) to 100 parts by solid content, blocked isocyanate (Takenate B, manufactured by Takeda Pharmaceutical Co., Ltd.)
-815N, ketoxime block, NCO 7.3%) solid content
37 parts (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin) were mixed with good stirring. This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness was 60 μm, and dried at 60 ° C. for 20 minutes to obtain a coating. The reaction rate of the obtained coating was 0% by IR measurement.

Comparative Example 7 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate and methacrylic acid and 2-aminoethyl acrylate, a weight average molecular weight of 78,000, a Tg of 25 ° C. and a COOH value of 40).
And NH ₂ value 20) to 100 parts by solid content, blocked isocyanate (Takeda Yakuhin Kogyo Co., Takenate B-815N, ketoxime block, NCO 7.3%) 18 parts by solid content Having an isocyanate group of 0.5 equivalent to the functional group of the water-soluble acrylic resin) and isocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.)
NCO (13.0%) was mixed with 13 parts of solid content (the amount by which 50% of the functional groups of the reactive acrylic resin reacts) while stirring well.

This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness was 50 μm, and dried at 60 ° C. for 20 minutes to obtain a coated product.

Comparative Example 8 300 parts of ethyl acetate was added to a reactive acrylic resin (a copolymer of methyl methacrylate, 2-hydroxyethyl acrylate and 2-aminoethyl acrylate, a weight average molecular weight of 153,00).
0, Tg35 ° C, OH value 60 and NH ₂ value 20) to 100 parts by solid content, blocked isocyanate (Takenate B, manufactured by Takeda Pharmaceutical Co., Ltd.)
-815N, ketoxime block, NCO 7.3%) solid content
49 parts (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the functional groups of the above-mentioned reactive acrylic resin) were mixed with good stirring.

This resin solution was spray-coated on a steel plate similar to that of Example 12 so that the film thickness was 60 μm, and dried at 60 ° C. for 20 minutes to obtain a coating.

The appearance, adhesion and pencil hardness of the sheets obtained in Examples 12 to 19 and Comparative Examples 5 to 8 were measured. The results are shown in Table 2.

(Effects of the Invention) The constitution of the covering sheet of the present invention is as described above, and it is a sheet that is excellent in spreadability and flexibility at a curing temperature or lower and forms a strong coating film after curing. Therefore, not only the flat surface but also the surface of the adherend having some irregularities and curved surfaces can be coated satisfactorily and with good workability without causing "wrinkles". Furthermore, even if the components are brought into contact with each other before heating, curing does not occur. Therefore, when the coating sheet is produced, the components can be uniformly mixed, and variations in physical properties are small. A film having a good appearance can be obtained.

Therefore, the thermosetting coating sheet is suitable not only for painting automobiles, home appliances, and building materials currently used for painting, but also for painting furniture and decorative accessories, and further for injection and the like. In molding, it can be integrated with resin.

Further, according to the coated article of the present invention, an article capable of forming a hard coating can be obtained without causing cracking or peeling of the thermosetting resin layer during processing of the coated article. Therefore,
Since it can be processed into a box type or dish type without any problems,
For example, it can be used as an article material for automobile outer panels, refrigerators, washing machines, home electric appliances such as microwave ovens, and furniture such as chairs and desks.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area C08J 5/18 CEY 9267-4F

Claims (4)

[Claims] 1. An acrylic resin which has at least two kinds of functional groups selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group, has a weight average molecular weight of 100,000 to 1,000,000, and is solid at room temperature, and a block. An uncured or semi-cured thermosetting coating sheet comprising a thermosetting resin composition containing isocyanate as a main component. 2. A main component comprising at least one crosslinking agent selected from the group consisting of unblocked isocyanate, melamine crosslinking agent and epoxy crosslinking agent, the acrylic resin according to claim 1, and blocked isocyanate. A semi-cured thermosetting coating sheet comprising the thermosetting resin composition described above. 3. A resin liquid containing the thermosetting resin composition according to claim 1 is applied to an adherend, and a part of the acrylic resin and a part of the blocked isocyanate contained in the resin liquid are heated by heating. A coated article obtained by reacting to form a semi-cured thermosetting resin layer. 4. A coated article obtained by applying a resin liquid containing the thermosetting resin composition according to claim 2 to an adherend to form a thermosetting resin layer in a semi-cured state.