JPH0715014B2 - 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 is to solve the above-mentioned drawbacks, and an object of the present invention is to provide 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 Problem) The thermosetting coating sheet of the present invention has a plurality of carboxyl groups, has a weight average molecular weight of 100,000 to 1,000,000, and a solid acrylic resin at room temperature, and a block. The thermosetting resin composition containing isocyanate as a main component is in an uncured or semi-cured state, whereby the above object is achieved. The coating of the present invention is obtained by applying a resin liquid containing the thermosetting resin composition onto the surface of an adherend and reacting a part of the acrylic resin and a part of the blocked isocyanate contained in the resin liquid by heating. Then, a thermosetting resin layer in a semi-cured state is formed to achieve 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. Other coatings of the present invention, a resin liquid containing the thermosetting resin composition is applied to the surface of the adherend, to form a thermosetting resin layer in a semi-cured state, thereby the above object To be achieved.

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 carboxyl group of the acrylic resin in the sheet reacts 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 carboxyl groups of the acrylic resin. Then, after applying 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 carboxyl group of the acrylic resin in the sheet and the isocyanate group of the blocked isocyanate. it can. in this way,
By using a semi-cured sheet, it is possible to further impart malleability and flexibility to the sheet to prevent cracks, cracks, etc. during processing, and impart flatness to enhance the appearance after curing. it can.

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 coating is processed into a desired shape, the coating is heated to the reaction temperature of the blocked isocyanate, thereby reacting the carboxyl group of the acrylic resin with the isocyanate group of the blocked isocyanate to form an article having a strong coating. Can be obtained.

Acrylic resin having a plurality of carboxyl groups used in the present invention (hereinafter referred to as acrylic polycarboxylic acid)
Is an acrylic polymer having a plurality of carboxyl groups and is a solid polymer at room temperature. Such an acrylic polycarboxylic acid includes, for example, various peroxides including a (meth) acrylic acid ester monomer, a styrene derivative monomer, and a (meth) acrylic acid ester monomer having a carboxyl group such as (meth) acrylic acid. It can be obtained by copolymerizing a chain transfer agent or the like as a catalyst.

Examples of the (meth) acrylic acid ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, and phenoxydiethylene glycol (meth) acrylate.

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 acrylic polycarboxylic acid can be changed depending on the conditions when carrying out the polymerization reaction using an initiator, and the acrylic polycarboxylic acid used in the present invention has a weight average molecular weight of 100,000-1,000,000
The range is selected. Weight average molecular weight 100,000
When it is below the range, it becomes difficult for the obtained covering sheet to maintain the sheet shape, 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. Further, the preferred range of Tg (glass transition point) and acid value (COOH value: the amount of COOH groups added during polymerization is calculated in the same manner as the OH value or quantified by KOH) of these acrylic polycarboxylic acids is It may be 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 -20 to 80 ° C. Acid value in the range of 20 ~
Those in the range of 200 are preferred. 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 acrylic polycarboxylic acid can also be used as a copolymer obtained by block- or graft-polymerizing a low-molecular weight acrylic polycarboxylic acid and another polymer or monomer. As other polymers or monomers, not only acrylic-based materials but also styrene-based, maleic acid-based, imide-based, etc. materials having good compatibility with acrylic-based materials, silicone-based materials, 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 weight average molecular weight of the mixture may be adjusted within the above range by mixing the above-mentioned acrylic polycarboxylic acid with the copolymer. Good. In the latter case, it is particularly advantageous to control the adhesive force to various adherends, for example, the surface of a polymer material such as melamine resin, epoxy resin, phenol resin, polycarbonate, acetal resin, or polyolefin.

The blocked isocyanate is mainly used as a heat-reactive curing agent for curing acrylic polycarboxylic acid. Here, the blocked isocyanate refers to an isocyanate group of an isocyanate compound having two or more isocyanate groups in the molecule, phenol, oxime, ε
-Means a compound blocked with a blocking agent such as caprolactam or malonate. As the above-mentioned isocyanate compound, for example, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, a monomer such as isophorone diisocyanate,
Alternatively, trimethylolpropane adducts thereof, isocyanurate modified products, carbodiimide modified products and the like can be mentioned. In the blocked isocyanate, the blocking agent is released by heating, and the resulting isocyanate group causes a crosslinking reaction with the carboxyl group of the acrylic polycarboxylic acid. The content of the blocked isocyanate is the ratio of the number of carboxyl groups of the acrylic polycarboxylic acid and the number of isocyanate groups contained in the blocked isocyanate (acid value / N
The CO value) is preferably adjusted to be in the range of 0.5 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 this isocyanate added varies depending on the sheet forming method, but is preferably such that the NCO of the acrylic polycarboxylic acid is COOH: NCO = 1: 0.01 to 0.9.

The melamine-based crosslinking agent, including melamine, urea, thiourea, guanidine, guanamine, acetoguanamine,
Benzoguanamine, trimethylol melamine obtained by reacting a material having a polyfunctional carboxyl group such as dicyandiamide with formaldehyde, trimethylol melamine, dimethylol urea, dimethylol guanidine, dimethylol aketoguanidine, dimethylol benzoguandin and the like are butyl alcohol and 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 carboxyl group of acrylic polycarboxylic acid like isocyanate, and it is preferable to determine the addition amount by performing a preliminary experiment before making a sheet when adding. However, for example, COOH: OR to the acid value of acrylic polycarboxylic acid
The amount is preferably (ether value) = 1: 0.1 to 1.2.

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 epoxy cross-linking agent added is
The amount is preferably H: CH ₂ CH ₂ O (epoxy group) = 0: 0.01 to 0.9. Further, since this epoxy cross-linking agent reacts with COOH groups to generate OH groups, the amount of the blocked isocyanate added at the same time is 3 to the equivalent of the remaining hydroxyl groups of the acrylic polycarboxylic acid and the generated hydroxyl groups. It is preferable to add a total amount of about 80%.

The addition amount of the above-mentioned cross-linking agent is preferably within the above-mentioned range, but actually the reaction of the cross-linking agents depending on the reactivity of the acrylic polycarboxylic acid 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 carboxyl group of acrylic polycarboxylic acid occurs, it is preferable to determine the actual amount to be added after conducting a preliminary experiment.

A reactive acrylic oligomer such as an acrylic polycarboxylic acid oligomer may be further added to the thermosetting resin composition of the present invention, if necessary, to impart further spreadability and flexibility to the adherend. You can

The acrylic polycarboxylic acid oligomer is an acrylic polymer having a plurality of carboxyl groups like the above-mentioned acrylic polycarboxylic acid, and is a solid or solid solution polymer at room temperature. Such an acrylic polycarboxylic acid oligomer includes, for example, a (meth) acrylic acid ester monomer and a (meth) acrylic acid ester monomer having a carboxyl group such as 2-aminoethyl (meth) acrylate as described above. It can be obtained by copolymerizing like an acid. In this case, the chain transfer agent is added in a much larger amount than in the case of the above-mentioned acrylic polycarboxylic acid and polymerized. As the acrylic polycarboxylic acid oligomer, those having a weight average molecular weight in the range of 1,000 to 10,000 are preferably used. When the weight average molecular weight of the acrylic polycarboxylic acid oligomer is less than 1,000, the obtained resin composition is poor in moldability, and it becomes difficult to handle the coating sheet. When the weight average molecular weight exceeds 10,000, the resulting sheet lacks flexibility and is inferior in moldability. Further, this acrylic polycarboxylic acid oligomer has a glass transition point of -50 ° C to 40 ° C due to the relationship between the moldability of the sheet and the film hardness after curing.
And the acid value is in the range of 80 to 250.
The addition amount of the acrylic polycarboxylic acid oligomer is preferably about 10 to 200 parts by weight with respect to 100 parts by weight of the solid content of the acrylic polycarboxylic acid. In addition, the acrylic polycarboxylic acid oligomer may be used in combination with a plurality of kinds of acrylic polycarboxylic acid oligomers as long as they are in 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 uncured sheet in which the carboxyl groups of the acrylic resin contained in the composition have not reacted, or a semi-cured state in which a part of them has been 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, it is preferable that 0.01% to 80% of the total number of the carboxyl groups of the acrylic resin before the reaction is reacted with the carboxyl groups of the acrylic resin contained in the sheet. That is, the reaction rate (initial curing rate) of the carboxyl group varies depending on the method of using the sheet. For example, if the adherend to be pasted has convex or vertical portions, or if the work of attaching the sheet is at a very high temperature (30 ° C or higher), make sure that elongation of 100% or more is obtained at the sheet forming temperature. , 0.01-40%, more preferably 1-30% of the carboxyl groups should be crosslinked with isocyanates. Also,
When the coating sheet is used in a place where high pressure acts on the sheet such as press molding or insert injection, use a material in which 20 to 80% of amino groups react so as to withstand the molding temperature and resin pressure. Is good. The value of the reaction rate of these carboxyl groups may vary somewhat within an appropriate range 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 covering sheet does not have sufficient adhesive force to the adherend to be coated, an adhesive layer is laminated on the back surface of the covering sheet, and the surface of the adherend is covered via this adhesive layer. Sheet may be attached. As the adhesive layer, for example, FVA 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 reactivity, the addition amount and reactivity of the acrylic polycarboxylic acid, the crosslinking agent, 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, in the semi-cured state, as in the case of the above-mentioned covering sheet, 5% to 80% of the total number of carboxyl groups of the acrylic resin before reaction contained in the thermosetting resin layer has reacted. The state is preferred. 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 carboxyl 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 acrylic polycarboxylic acid and the blocked isocyanate are the same as in the case of the coating sheet. The reaction temperature depends on the blocking agent of the blocked isocyanate, the acid value of the acrylic polycarboxylic acid and the addition amount of the blocked isocyanate,
And the reaction time is determined by their reactivity and the like. For example, as a blocked isocyanate, a methyl ethyl ketone oxime block (isophorone diisocyanate:
When using (non-catalyst state), if the NCO value is 1: 1 with respect to acrylic polycarboxylic acid (acid value 80), 2% at 160 ° C for 1 minute, 18% for 5 minutes, 40% for 10 minutes , 80% in 18 minutes
It will be 100% complete curing reaction in 30 minutes.

In this method of confirming the reaction status, the acid 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 carboxyl group of the acrylic polycarboxylic acid, the reaction between the isocyanate and the isocyanate through 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 solvent is applied from a spray gun to a coating solution such as casting to apply the resin solution uniformly on the adherend surface, 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 forming the thermosetting resin layer by hot air, radiant heat of infrared rays, etc. under the conditions of temperature, time, etc. mentioned above, heating is carried out in order to reduce the distribution of the curing rate with respect to the thickness of the coating. It is preferable to uniformly heat the entire coating film.

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 2371).

Example 1 Acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 235,000, Tg 20 ° C., acid value 60) was blocked to 100 parts by solids in 300 parts of ethyl acetate and blocked. Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) were mixed with 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 100μ
It was m.

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 Acrylic polycarboxylic acid (a copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 360,000, Tg 35 ° C., acid value 80) was blocked to 100 parts by solids in 300 parts of ethyl acetate, and blocked. Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%) 59 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) 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. 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 obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 3 Acrylic polycarboxylic acid (a copolymer of methyl methacrylate and methacrylic acid and butyl acrylate, a weight average molecular weight of 620,000, Tg 0 ° C., an acid value of 40) was blocked in 300 parts of ethyl acetate in 100 parts by solid content, and blocked. Acrylic polycarboxylic acid (copolymer of stearyl methacrylate and methacrylic acid, weight average molecular weight 25,000, Tg20 ° C, acid value 20) 10 parts by solid content,
Blocked isocyanate (Nippon Polyurethane Industry, Coronate 2513, Ethyl acetoacetate block, NCO 10.2
%) 25 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the above acrylic polycarboxylic acid and blocked acrylic polycarboxylic acid) 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 120 μm.

Next, the above-mentioned sheet was attached to a polypropylene hemisphere having a radius of 15 cm by vacuum adhesion molding at 60 ° C when the ultimate vacuum reached 6 Torr, then at 120 ° C for 2 minutes, and further 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 and acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight of 260,000, Tg of 40 ° C., acid value of 80) were blocked in 100 parts of solid content. Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%) 59 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) 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
Of the carboxyl group
25% were reacting. 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 pencil hardness of the obtained coating is HB, and the adhesion is 100/1 in a 1 mm width cross-cut test.
It was 00.

Example 5 To 300 parts of ethyl acetate, 100 parts of acrylic polycarboxylic acid (copolymer of methyl methacrylate, acrylic acid and ethyl acrylate, weight average molecular weight 220,000, Tg15 ° C., acid value 80) in solid content, acrylic 40 parts of polyamine oligomer (copolymer of ethyl acrylate and 2-aminoethyl methacrylate, weight average molecular weight 5,000, Tg-10 ° C, NH ₂ value 100) in solid content, blocked isocyanate (Takenate B, manufactured by Takeda Pharmaceutical Co., Ltd.) -815N, ketoxime block, NC
O7.3%) 89 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid and amino groups of the acrylic polyamine oligomer), 40 parts of titanium oxide are well stirred While mixing. 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 150
was μm.

Next, the above-mentioned sheet was heated to 100 ° C. by vacuum adhesion molding, and the length and width of the stainless steel SUS-304 was 15 cm, and a rectangular parallelepiped having a height of 10 cm was applied at 80 ° C. When the ultimate vacuum reached 6 Torr, it was attached. Then, it was heated and cured at 160 ° C. for 30 minutes to obtain a coating. The pencil hardness of the coating was H, and the adhesion was 100/100 in a 1 mm width cross-cut test.

Example 6 To 300 parts of ethyl acetate, 100 parts of acrylic polycarboxylic acid (copolymer of methyl acrylate, methacrylic acid and butyl acrylate, weight average molecular weight 730,000, Tg 10 ° C., acid value 40) in solid content, acrylic Polycarboxylic acid oligomer (copolymer of ethyl acrylate and methacrylic acid, weight average molecular weight 25,000, Tg-20 ° C, acid value 50) 20 parts by solid content, blocked isocyanate (Nippon Polyurethane Industry Co., Ltd., Coronate 2513, Acetate) Ethyl acetate block, NCO 10.2%)
A solid content of 28 parts (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid and the acrylic polycarboxylic acid oligomer) and 2 parts of zinc chromate were thoroughly mixed. 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 heated to 100 ° C. by vacuum contact molding, and a cube of steel plate SS-41 (dilute nitric acid treatment-washed with ion-exchanged water) having a side of 10 cm was set to 80 ° C.
When it reached 6 Torr, it was attached 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 blocked with acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 153,000, Tg 35 ° C., acid value 60) in 100 parts by solid content. Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate group with respect to the carboxyl group of the acrylic polycarboxylic acid), epoxy-based crosslinking agent (manufactured by Ciba-Geigy, Araldide CY175, epoxy equivalent, An epoxy value of 220) corresponding to the acid value of 3.7 parts (the amount by which 10% of the carboxyl groups of the acrylic polycarboxylic acid reacts) was mixed while stirring well. 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 80 μm.

Next, the ultimate vacuum degree was reached at 50 ° C on a hemisphere with a radius of 10 cm, which was obtained by coating the above sheet by alkyd melamine by vacuum contact molding.
When it reached 7 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 Acrylic polycarboxylic acid (a copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, a weight average molecular weight of 450,000, Tg of 35 ° C., an acid value of 80) was blocked to 300 parts of ethyl acetate in a solid content of 100 parts and blocked. Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO7.3%) 59 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), isocyanate (Nippon Polyurethane Industry Co., Coronate L, NCO1
3.0%) was mixed with 10 parts by solid content (amount in which 30% of the carboxyl groups of the acrylic polycarboxylic acid reacts) 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. The film thickness of the sheet was 200 μm.

Next, using a vacuum press (dish-shaped die), stick the above sheet to a plate made of steel plate (SS41) with a radius of 10 cm, a height of 6 cm and a bottom radius of 6 cm at 100 ° C, and then at 160 ° C for 30 minutes. The coating was obtained by heating and curing. The obtained coating had a pencil hardness of H and an adhesion of 100/100 in a 1 mm width cross-cut test.

Example 9 Acrylic polycarboxylic acid (copolymer of methyl methacrylate, acrylic acid and butyl acrylate, weight average molecular weight 210,000, Tg10 ° C., acid value 40) was blocked to 100 parts by solids in 300 parts of ethyl acetate, and blocked. Acrylic polycarboxylic acid (copolymer of stearyl methacrylate and methacrylic acid, weight average molecular weight 25,000, Tg20 ° C, acid value 20) 10 parts by solid content,
Blocked isocyanate (Nippon Polyurethane Industry, Coronate 2513, Ethyl acetoacetate block, NCO 10.2
%) 25 parts by solids (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the above-mentioned acrylic polycarboxylic acid and blocked acrylic polycarboxylic acid), isocyanate (Nippon Polyurethane Industry, Coronate L, NCO13 0.0%) was mixed with 1.8 parts of solid content (the amount by which 10% of the carboxyl groups reacts) while stirring well. 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 15 cm at 60 ° C. when the ultimate vacuum reached 10 Torr, and then heat cured at 120 ° C. for 20 minutes and then 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, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 260,000, Tg35 ℃, acid value 80) in 100 parts by solid content, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO7.3%) 39 parts by solid content (this blocked isocyanate has 0.8 equivalent of isocyanate groups to the carboxyl groups of the acrylic polycarboxylic acid) and a melamine-based cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Becker Min (butylated melamine resin) J-820-60 (56 parts by solid content) (amount capable of reacting 60% of the carboxyl groups) was 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. The film thickness of the sheet was 60 μm.

Next, this sheet was fixed to the inner peripheral surface of the cavity of the injection mold in the same manner as in Example 4, and the polyetherimide resin was injected. Then, it was heated and cured at 160 ° C. for 20 minutes to obtain a coating. The pencil hardness of the obtained coating is
The HB and adhesion were 100/100 in a 1 mm width cross-cut test.

Example 11 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and butyl acrylate, weight average molecular weight 470,000, Tg10 ℃, acid value 40) to 100 parts by solid content, acrylic 20 parts by weight of polycarboxylic acid oligomer (copolymer of ethyl acrylate and acrylic acid, weight average molecular weight 5,000, Tg-30 ° C, acid value 50) in solid content,
Blocked isocyanate (Nippon Polyurethane Industry, Coronate 2513, Ethyl acetoacetate block, NCO 10.2
%) Solid content 29 parts (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid and acrylic polycarboxylic acid oligomer), isocyanate (Nippon Polyurethane Industry Co., Coronate L, NCO13 .0%) as solid content 2.2 parts (10% of carboxyl groups react), zinc chromate
2.5 parts were mixed with good stirring. Apply this resin solution to the release surface of PET film with an applicator and apply at 70 ℃ for 10
After drying for a minute, a thermosetting coating sheet was obtained. The film thickness of the sheet was 80 μm.

Next, the sheet was attached by vacuum contact molding to a cube similar to that of Example 6 at 80 ° C. when the ultimate vacuum reached 10 Torr, 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, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 363,000, Tg35 ℃, acid value 60) in 100 parts by solids, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) were mixed with good stirring. Apply this resin solution to a steel plate (SS-41, thickness 2 m
m, diluted nitric acid treatment-washed with ion-exchanged water) has a film thickness of 6
The coating was obtained by spray coating to a thickness of 0 μm, drying at 60 ° C. for 20 minutes, and then heat curing at 160 ° C. for 10 minutes.
The reaction rate of the obtained coating was 35% by IR measurement.

Example 13 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 260,000, Tg40 ℃, acid value 80) in 100 parts by solid content, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%, ethyl acetate solvent) 49 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), 60 parts of titanium oxide are mixed with good stirring did.
This resin solution was spray-coated on a steel plate similar to that used in Example 12 so that the film thickness was 50 μm, dried at 60 ° C. for 20 minutes, and then 16
A coating was obtained by heat curing at 0 ° C. for 3 minutes. The reaction rate of the coating was 8% by IR measurement.

Example 14 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and acrylic acid and butyl acrylate, weight average molecular weight 210,000, Tg10 ℃, acid value 100) to 100 parts by solid content, block Acrylic polycarboxylic acid (copolymer of stearyl methacrylate and methacrylic acid, weight average molecular weight 25,000, Tg20 ° C, acid value 20) 10 parts by solid content,
Blocked isocyanate (Nippon Polyurethane Industry, Coronate 2513, Ethyl acetoacetate block, NCO 10.2
%) 60 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the above-mentioned acrylic polycarboxylic acid and blocked acrylic polycarboxylic acid) were mixed with good stirring. 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 is
It was 70% by IR measurement.

Example 15 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 363,000, Tg35 ℃, acid value 60) to 100 parts by solids, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%, ethyl acetate solvent) 49 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), 60 parts of titanium oxide are mixed with good stirring did.
This resin solution was spray-coated on a steel plate similar to that used in Example 12 so that the film thickness was 50 μm, dried at 60 ° C. for 20 minutes, and then 16
A coating was obtained by heat curing at 0 ° C for 15 minutes. The reaction rate of the obtained coating was 72% by IR measurement.

Example 16 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 202,000, Tg35 ℃, acid value 100) in 100 parts by solid content, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%) 49 parts by solid content (this blocked isocyanate has 0.8 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) and a melamine-based cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Becker). Min (butylated melamine resin) J-820-60) (30 parts by solid content) (amount in which 40% of the carboxyl groups react) was 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.

Example 17 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 580,000, Tg35 ℃, acid value 80) to 100 parts by solid content, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO 7.3%, ethyl acetate solvent) 39 parts by solid content (this blocked isocyanate has 0.8 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), isocyanate (Nippon Polyurethane Industry, Coronate L, NCO 13.0%) was mixed with 17 parts of solid content (amount in which 50% of carboxyl groups reacts) and 60 parts of titanium oxide 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, and dried at 60 ° C. for 20 minutes to obtain a coated product.

Example 18 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and acrylic acid and butyl acrylate, weight average molecular weight 450,000, Tg10 ℃, acid value 40) in 100 parts of solid content, acrylic Polycarboxylic acid oligomer (copolymer of ethyl acrylate and acrylic acid and butyl methacrylate, weight average molecular weight 5,000, Tg-20 ° C, acid value 20) is 10 parts by solid content, blocked isocyanate (Nippon Polyurethane Industry Co., Coronate) 2513, NCO 10.2%) 13 by solids
Parts (this blocked isocyanate has 0.5 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid and acrylic carboxylic acid oligomer) and isocyanate (Nippon Polyurethane Industry Co., Coronate L, NCO 13.0%) in solid content Then, 13 parts (the amount by which 70% of the carboxyl groups react) 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 20 μm, and dried at 60 ° C. for 20 minutes to obtain a coating.

Example 19 300 parts of ethyl acetate, acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 202,000, Tg35 ℃, acid value 100) in 100 parts by solid content, block Isocyanate (Takeda Yakuhin Kogyo, Takenate B-815N, ketoxime block,
NCO7.3%, ethyl acetate solvent) 42 parts by solid content (this blocked isocyanate has 0.7 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), epoxy-based cross-linking agent (Ciba Geigy, Araldide CY175 , An epoxy equivalent of 160, an epoxy value of 220 corresponding to an acid value of 18 parts (an amount at which 50% of the carboxyl groups react), and 60 parts of titanium oxide 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, and dried at 60 ° C. for 20 minutes to obtain a coated product.

Comparative Example 1 In Example 1, except that acrylic polycarboxylic acid having a weight average molecular weight of 52,000 (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, Tg 20 ° C., acid value 60) was used as the acrylic polycarboxylic acid. In the same manner as in Example 1, a coating sheet having a film thickness of 100 μm was obtained.

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, except that acrylic polycarboxylic acid having a weight average molecular weight of 60,000 (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, Tg 25 ° C., acid value 80) was used as the acrylic polycarboxylic acid. In the same manner as in Example 2, a coating sheet having a film thickness of 200 μm was obtained.

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 Acrylic polycarboxylic acid (a copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, a weight average molecular weight of 52,000, Tg of 35 ° C., an acid value of 60) was blocked in 100 parts of solids in 300 parts of ethyl acetate. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) 38 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid), isocyanate (Nippon Polyurethane Industry Co., Coronate L, NCO1)
3.0%) was mixed with 2.8 parts (amount in which 10% of the carboxyl groups reacts) in terms of solid content 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 and acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 60,000, Tg15 ° C., acid value 80) were blocked to 100 parts by solid content. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) 59 parts by solid content (this blocked isocyanate has 1.2 equivalents of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) and a melamine cross-linking agent (manufactured by Dainippon Ink and Chemicals, Super Becker). Mining (butylated melamine resin) J-820-60) 28 parts (amount reacting with 30% of carboxyl groups) in solid content was mixed with good stirring. This resin solution was applied and dried in the same manner as in Example 1 to obtain a thermosetting coating sheet. Sheet thickness is 20
It was 0 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 In 300 parts of ethyl acetate, acrylic polycarboxylic acid (a copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 23,000, Tg 35 ° C., acid value 60) was blocked in 100 parts by solid content. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) were mixed with good stirring. This resin solution was spray-coated on a steel plate similar to that in Example 12 to a film thickness of 50 μm, and the coating was performed at 60 ° C. for 20 minutes.
The coating was obtained by drying for 1 minute and then heat curing at 160 ° C. for 15 minutes. The reaction rate of the obtained coating was 70% by IR measurement.

Comparative Example 6 Acrylic polycarboxylic acid (a copolymer of methyl methacrylate and acrylic acid and ethyl acrylate, weight average molecular weight 153,000, Tg 35 ° C., acid value 60) was blocked to 100 parts by solids in 300 parts of ethyl acetate. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) were mixed with good stirring. This resin solution was spray-coated on a steel plate similar to that in Example 12 to a film thickness of 60 μm, and the coating was performed at 60 ° C. for 20 minutes.
A coating was obtained after drying for one minute. The reaction rate of the obtained coating is
It was 0% by IR measurement.

Comparative Example 7 Acrylic polycarboxylic acid (copolymer of methyl methacrylate and methacrylic acid and ethyl acrylate, weight average molecular weight 28,000, Tg 35 ° C., acid value 60) was blocked to 100 parts by solids in 300 parts of ethyl acetate, and blocked. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) solid content 19 parts (this blocked isocyanate has 0.5 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) and isocyanate (Nippon Polyurethane Industry Co., Ltd., Coronate L, NC)
O13.0%) was mixed with 13 parts (amount reacting 50% of the carboxyl groups) in solid content 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, and dried at 60 ° C. for 20 minutes to obtain a coated product.

Comparative Example 8 Acrylic polycarboxylic acid (copolymer of methyl methacrylate and acrylic acid and ethyl acrylate, weight average molecular weight 153,000, Tg 35 ° C., acid value 60) was blocked to 100 parts by solids in 300 parts of ethyl acetate, and blocked. Isocyanate (manufactured by Takeda Pharmaceutical Co., Takenate B-815N, ketoxime block, NC
O7.3%) 37 parts by solid content (this blocked isocyanate has 1.0 equivalent of isocyanate groups with respect to the carboxyl groups of the acrylic polycarboxylic acid) 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 Internal reference number FI technical display location C08J 5/18 CEY 9267-4F

Claims (4)

[Claims] 1. A thermosetting resin composition comprising a plurality of carboxyl groups, a weight average molecular weight of 100,000 to 1,000,000, and a solid acrylic resin at room temperature, and a blocked isocyanate as a main component. An uncured or semi-cured thermosetting coating sheet. 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.