JPH0623318A - Method for manufacturing fabricated product of coated metal plate - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a processed metal plate product by imparting processability over time and high hardness and stain resistance contradictory thereto to a coating film formed by a precoat metal method. It is an object of the present invention to provide a method for producing a coated metal plate processed product, which is capable of forming a uniform coating film having a high hardness and a high stain resistance on the surface thereof. According to the present invention, there is provided a coating material comprising (I) a polymer having a polymerizable double bond and a crosslinkable functional group on a metal plate, and (B) a crosslinking agent which reacts with the functional group by heating. A step of coating and irradiating with active energy rays to form a primary cured coating film, (II) a step of forming a metal plate on which a primary cured coating film is formed, and (III) a formed metal Provided is a method for producing a coated metal plate processed product, which comprises the steps of baking a plate and completely curing the primary cured coating film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating film on the surface of a product formed by processing a metal plate (hereinafter referred to as a metal plate processed product), which has a particularly complicated shape. The present invention relates to a method for producing a coated metal plate processed product, which can form a uniform coating having a high hardness and a high stain resistance on the surface of the metal plate processed product.

[0002]

2. Description of the Related Art Conventionally, electric appliances, kitchen appliances, office equipment,
For the coating of roofing materials, outer wall siding materials, etc., the so-called post-coating method, in which an unpainted metal plate is formed by cutting, bending, squeezing, etc. and then painting, is the mainstream. The coating method is not only poor in coating workability, but also when the object to be coated has a complicated shape,
There was a problem that it was difficult to coat the entire surface uniformly. Therefore, a plate-shaped or coil-shaped metal plate such as a galvanized steel plate, a cold-rolled steel plate, an aluminum plate, and a stainless plate is pre-painted, the coating film is hardened, and then this coated metal plate is formed and processed. The (PCM) method has been adopted. But,
The coating film formed by the precoat metal method has the workability (that is, flexibility) of the coating film that can follow the elongation and bending of the metal material during the forming process, and at the same time, the high processability that is contradictory to this processability after the forming process. There is a contradiction that hardness and stain resistance are required. For this reason, a paint for precoat metal that satisfies both requirements has not been developed yet.

As a coating material used in the precoat metal method, a composition comprising a polyester resin, a curing agent therefor and a radiation-curable monomer or oligomer is undercoated on a metal plate and heat-cured, and then a radiation-curable coating material. A method of overcoating and radiation curing (JP-A-62-1258).
79), a polyester resin having active hydrogen, and a coating composition curable by an electron beam and heat, which contains a compound having a group capable of reacting with active hydrogen as an essential component (JP-A-2-
No. 102279 gazette) has been developed, but a coating film formed from these coating materials has a sufficient workability, but has a drawback of low hardness, and Japanese Patent Publication No. 56-807.
On the contrary, the method disclosed in Japanese Patent Publication No. 0 has a drawback that the hardness of the coating film is very high but the workability is insufficient, and the coating film has both high workability and high hardness. No coating film was obtained. Further, a coating composition using both ultraviolet curing and heat curing is generally known (for example, JP-A-60-112865, JP-A 2-10).
No. 3216), the hardness of the obtained coating film was insufficient.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art, and gradually imparts processability and contradictory high hardness and stain resistance to the coating film formed by the precoat metal method. By doing so, it is an object of the present invention to provide a method for producing a coated metal plate product, which can form a uniform coating film with high hardness and high stain resistance on the surface of the metal plate product.

[0005]

[Means for Solving the Problems] That is, the present invention is a method for producing a coated metal plate product, which comprises (I) a metal plate having (A) a polymerizable double bond and a crosslinkable functional group. Coupling and (B) a step of applying a coating material containing a crosslinking agent that reacts with the functional group by heating, irradiating with active energy rays to form a primary cured coating film, (II) primary cured coating film And (III) baking the formed metal plate to completely cure the primary cured coating film. It provides the law. Hereinafter, the present invention will be described in detail. The coating composition used in the present invention is mainly composed of a polymer (A) having a polymerizable double bond and a crosslinkable functional group, and a crosslinking agent (B) capable of reacting with the functional group by heating (B). Is. This coating composition is applied to a metal plate and then irradiated with active energy rays so that the polymerizable double bond of the polymer (A) reacts and undergoes radical polymerization to form a primary cured coating film. . At this stage, the cross-linking agent (B) in the composition did not substantially undergo cross-linking reaction with the polymer (A).
Since (B) has a kind of plasticizer function for the coating film,
The coating film has high flexibility, and the primary cured coating film has high processability.

Such a highly curable primary cured coating film is
Since it can easily follow the elongation and bending of the metal material during the metal plate forming process, the metal plate with the primary cured coating film cracks on the coating surface while maintaining the uniformity and aesthetics of the coating film. It can be molded without causing cracks or other scratches. After the molding process, the primary cured coating film is baked to completely cure the coating film, so that the functional group in the polymer (A) reacts with the crosslinking agent (B) to crosslink in a network. Since the structure is formed, a coating film having high hardness and excellent stain resistance can be obtained. Polymer (A) and crosslinking agent in the present invention
As the combination of (B), a binder used in various conventionally known thermosetting coatings, that is, a combination of a polymer having a functional group and a crosslinking agent capable of reacting with the functional group by heating, is particularly preferable. It can be applied without limitation, and the polymer (A) of the present invention has a polymerizable double bond in addition to this functional group.

In the present invention, the polymer (A) having a hydroxyl group as a functional group and an aminoplast compound are used as a crosslinking agent.
The polymer used in the present invention, in which the combination (B) is preferable.
As (A), a conventionally known polymer having a polymerizable double bond and a crosslinkable functional group can be used without particular limitation. Among them, vinyl polymer, unsaturated polyester resin, epoxy resin , And fluororesins can be mentioned as typical ones. Of these, the following vinyl polymers are particularly preferable. This vinyl polymer having a polymerizable double bond and a crosslinkable hydroxyl group has a hydroxyl value of about 10 to 120 mg KOH / g, particularly 30 to 100 mg KOH.
polymer 1 containing a polymerizable double bond.
About 0.01 to 0.2 mol, especially 0.05 to 0.15 per 00 g
It is preferable that the content of the polymer is 50 mol% or more, especially 65 to 90 wt% of the methyl methacrylate unit in the main chain of the polymer. The weight average molecular weight of the vinyl polymer is preferably 10,000 to 300,000, particularly preferably 30,000 to 200,000. In addition to the hydroxyl group, a functional group such as a carboxyl group or an amino group may be used in combination as the functional group.

As a method for producing such a vinyl-based polymer, a vinyl copolymer (X) having a functional group is prepared by adding an ethylenically unsaturated monomer (Y) having a functional group reactive with the functional group. ) Can be mentioned as a typical method. However, the copolymer (X) and the monomer (Y)
It is necessary to make at least one of the functional groups of the above a part or all of them into a hydroxyl group and react them so that the hydroxyl groups remain in the above proportion even after both react. In addition, since the glycidyl group also changes into a hydroxyl group by the reaction, it is possible to use the copolymer (X) or the monomer (Y) having a glycidyl group. As the vinyl copolymer (X), methyl methacrylate and a functional group-containing ethylenically unsaturated monomer (a), or those and other ethylenically unsaturated monomers
(b) and, for example, in the presence of an ordinary peroxide-based or azo-based radical polymerization initiator at about 80 to 140 ° C. for 3 to 10
A typical example is a copolymer obtained by reacting for a period of time.

Typical examples of the ethylenically unsaturated monomer (a) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and glycoloxy (meth) acrylate. Hydroxyl group-containing monomers such as ethyl; carboxyl group-containing monomers such as (meth) acrylic acid; glycidyl group-containing monomers such as glycidyl (meth) acrylate; (meth) acrylic acid-t-butylaminoethyl and the like Amino group-containing monomers; amine-methacrylimides such as trimethylamine-methacrylimide, N-methylolacrylamide, Nn-butoxymethylacrylamide, acrylamides and the like. In addition, typical examples of the other ethylenically unsaturated monomer (b) include methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl. (Meth) acrylic such as (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate. Acid esters; Substituted styrenes such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene; (meth) acrylonitrile, vinyl chloride, vinyl formate, vinyl acetate, vinyl propionate, vinyl stearate, dialkyl maleate Divinylbenzene and the like. The ethylenically unsaturated monomer (Y)
Is a polymerizable double bond in the vinyl copolymer (X) and /
Alternatively, in order to introduce a hydroxyl group, a vinyl copolymer (X)
React with.

As the ethylenically unsaturated monomer (Y), when the functional group in the vinyl copolymer (X) is a hydroxyl group, the carboxyl group-containing monomer and the glycidyl group-containing monomer are included. Body, amine-methacrylimides, acrylamides, isocyanate group-containing monomers such as isocyanate ethyl (meth) acrylate,
When the functional group in the vinyl copolymer (X) is a carboxyl group, it is the glycidyl group-containing monomer, amine-methacrylimides, acrylamides, amino group-containing monomer, or the like, and the vinyl copolymer is further included. When the functional group in (X) is a glycidyl group, it is the above-mentioned carboxyl group-containing monomer, hydroxyl group-containing monomer, amino group-containing monomer, amine-methacrylimides or acrylamides. When the functional group in the vinyl copolymer (X) is an amino group, the isocyanate group-containing monomer, the carboxyl group-containing monomer, the glycidyl group-containing monomer and the like can be mentioned as typical ones. . These ethylenically unsaturated monomer (Y) and vinyl copolymer (X) can be reacted in the presence of an ordinary catalyst at 0 to 150 ° C. for 30 minutes to 15 hours.

The polymer (A) can be produced under the above-mentioned starting materials and conditions, but the reactivity between the polymer (A) and the cross-linking agent (B) is increased, and the adhesion to a metal plate, etc. In order to impart the above, it is also possible to impart a functional group other than the hydroxyl group to the polymer (A). Aminoplast compounds suitable as the crosslinking agent (B) of the present invention include amino compounds such as melamine, urea, and benzoguanamine, self-condensates thereof, condensates of these amino compounds and aldehyde compounds, or condensates thereof. Examples thereof include those etherified with alcohols such as methanol and butanol. Among these aminoplast compounds, compounds having a triazine ring structure represented by the following general formula (i) or condensates thereof having a molecular weight of about 6,000 or less are particularly preferable in the present invention.

[0012]

[Chemical 3]

[Wherein R is —H, —CH ₂ OH, —CH ₂ OC
_{H 3, -CH 2 OC 4 H} 9, -CH 2 OC (O) CH = CH 2, -CH 2 OC (O) C (C
_{H 3) = CH 2, -CH} 2 NHC (O) CH = CH 2 or _{-CH 2 NHC (O) C (} CH 3) = C
H _{2 is} a kind of H ₂ , and R may be different or the same. ]

Commercially available aminoplast compounds include, for example, Uban 2 as a butyletherified melamine resin.
0SE [trade name, manufactured by Mitsui Toatsu Chemicals, Inc.], cymel as a methyl etherified or mixed etherified melamine resin [trade name, manufactured by Mitsui Cyanamide Co., Ltd.], and esramine as a partially acryloylated methoxymethylol melamine resin [trade name] , Shin-Nakamura Chemical Co., Ltd.] and the like. In the coating composition used in the present invention, the crosslinking agent (B)
Is about 30 to 150 parts by weight with respect to 100 parts by weight of the polymer (A),
It is particularly preferable to use it in a proportion of 60 to 120 parts by weight.
When the proportion of the cross-linking agent (B) is less than 30 parts by weight, the hardness of the coating film tends to decrease, and when it exceeds 150 parts by weight, the coating film after processing becomes tacky and plastic deformation of the coating film occurs. Becomes larger, the recovery of creep deformation during storage tends to be difficult.

When the active energy ray irradiated in the manufacturing process is ultraviolet rays, a photopolymerization initiator must be added to the coating composition used in the present invention. Specific examples of the photopolymerization initiator include benzoin, benzoin alkyl ethers, anthraquinone derivatives, benzanthrone derivatives, and 2,2-dimethoxy-.
2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane, benzyl derivative, benzophenone derivative, xanthone derivative, thioxanthone derivative, bisimidazoles, acyl Phosphines, 4,4'-bis-dimethylaminobenzophenone, trichloromethyl-8-triazine,
There are 3,4,3 ', 4'-tetra (t-butylperoxycarbonyl) benzophenone and the like, and combinations of these with amine compounds and the like. These should be used alone or as a mixture of two or more kinds. You can

The photopolymerization initiator is preferably used in a proportion of 0.05 to 10 parts by weight, particularly 0.1 to 6 parts by weight, based on 100 parts by weight of the polymer (A). However, when the active energy ray is an electron beam, it may be blended as necessary. The coating composition used in the present invention, if necessary,
Various kinds of additives such as various reactive oligomers, reactive diluents, non-reactive diluents, color pigments, extender pigments, plasticizers, other dispersants, polymerization inhibitors and crosslinking catalysts can be added. The oligomer has a number average molecular weight of 500 to 1
50,000 urethane (meth) acrylate oligomers,
An epoxy (meth) acrylate oligomer etc. can be mentioned. These oligomers are suitably added in an amount of 10 parts by weight or less, preferably 2 to 5 parts by weight, based on 100 parts by weight of the polymer (A).

Examples of the reactive diluent include glycidyl (meth) acrylate, glycerol (meth) acrylate and glucoxy (meth).
Acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
Ethylene oxide modified phosphoric acid (meth) acrylate,
A monomer having a polymerizable double bond and a crosslinkable hydroxyl group, such as ethylene oxide, butanol modified phosphoric acid (meth) acrylate, ethylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate.
A monomer having a polymerizable double bond and a crosslinkable carboxyl group such as (meth) acrylic acid, other methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, propyl (meth) acrylate, hexyl ( (Meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, vinyltoluene, styrene, vinyl acetate, vinyl isobutyl ether, 2-ethylhexyl vinyl ether, acrylonitrile, N-vinylbenzene, dimethyl (meth)
For example, acrylamide. Examples of non-reactive diluents include toluene, xylene, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diethylene glycol monoethyl ether acetate, and water. is there. These diluents are preferably blended so that the viscosity of the coating composition is about 20 to 150 seconds (Ford cup No. 4/20 ° C).

Next, each step of the manufacturing method of the present invention will be described. First, in the step (I), a wide range of metal plates such as a galvanized steel plate, a cold-rolled steel plate, an aluminum plate, and a stainless plate, which are selected according to the purpose of use, are subjected to degreasing treatment, surface treatment, primer as necessary. The coating composition is applied, and the coating composition is applied to the metal plate by means such as spray coating, roller coating and curtain flow coating. It is appropriate that the coating amount is such that the dry film thickness is about 10 to 300 μm. Then, the coating surface is irradiated with active energy rays to cure the coating film, thereby forming a primary cured coating film. When using a coating composition containing a non-reactive diluent, before irradiating with active energy rays,
It is preferable to evaporate the non-reactive diluent in the coating film. At this time, the functional group of the polymer (A) and the cross-linking agent (B) may be heat-treated at a temperature at which the cross-linking reaction does not substantially occur (for example, 120 ° C. or less). In the present invention, as the active energy rays, high-energy radiation such as X-rays, α-rays, β-rays, γ-rays, electron beams and neutron rays, and ultraviolet rays can be used. It is necessary to add a photopolymerization initiator to the coating composition of the invention.

Typical examples of the electron beam source include Cockcroft type, Van de Graaf type, resonance transformer type, dynamitron type and high frequency type, and the dose is 0.1 to 20. Suitably Megarad. Typical examples of the ultraviolet ray irradiation source include a mercury lamp, a xenon lamp, a metal halide lamp, and a carbon arc.
It is suitable to set it up to 2000 mj / cm ² . In this way, the coating film is cured by the active energy ray in the step (I) to form a primary cured coating film. At the stage where step (I) is completed, the functional group in the polymer (A) (and the functional group in the reactive diluent) and the cross-linking agent (B) have not substantially reacted.

Next, in step (II), the coated metal plate obtained in step (I) is formed into a desired shape by cutting, bending, squeezing, or the like. The coated metal plate obtained in the step (I) does not need to be immediately subjected to the forming process in the step (II), but can be formed after being stored for a certain period of time. After forming the coated metal plate in this way, in step (III), put it in a heating furnace etc. to perform baking treatment, and to remove the functional group of the polymer (A) (and the functional group in the reactive diluent). By crosslinking reaction with the crosslinking agent (B), the primary cured coating film is completely cured to form a coating film having high hardness and excellent stain resistance. The baking conditions are about 130
Suitably heating at ~ 300 ° C for about 1 to 30 minutes. In the present invention, a coated metal plate processed product is manufactured as described above, but when the coated metal plate is irradiated with an active energy ray, for the purpose of preventing coating film curing and isolation due to oxygen, or damage to the coating film, etc. For the purpose of prevention, it is desirable to laminate a protective film of polyethylene, polyethylene terephthalate or the like with a thickness of 20 to 1000 μm before or after irradiating the coated metal plate with active energy rays. The protective film is removed before starting the baking step (III).

[0021]

According to the production method of the present invention, when a coated metal plate is processed, a primary cured coating film having good flexibility and high workability is formed on the surface of the metal plate. Even when processed, the coating film easily follows the elongation and bending of the metal material, maintaining the uniformity and aesthetics of the coating film, and without causing cracks or cracks on the coating surface. After the molding process, the primary cured coating film is baked to completely cure the coating film to form a crosslinked structure in the coating film, which has high hardness and excellent stain resistance. A final coating is obtained. That is, the workability of the primary cured coating film (JIS G3312 12.2 inner spacing of bending: 0 plate of the indicated thickness) is OT, and the pencil hardness (JIS K5400 8.4.2) of the final coating film is 5H or more. A coating film is obtained, and therefore, the present invention and the metal sheet formed product manufactured according to the present invention have high industrial utility value.

[0022]

(Synthesis of polymer (A))

(Synthesis Example 1) 103.7 parts of butyl acetate was charged into a four-necked flask, heated to 92 ° C. in a nitrogen stream, and stirred with stirring, 128.5 parts of methyl methacrylate and ethyl acrylate.
15.5 parts, acrylic acid 9 parts and butyl acetate 125 parts to tertiary butyl peroxy 2-ethylhexanoate.
A mixture prepared by dissolving 3 parts in advance was added dropwise over 3 hours. Then, the temperature was raised to 98 ° C. over 1 hour, and a mixture of 0.3 part of tert-butyl peroxy 2-ethylhexanoate in 90 parts of butyl acetate was added dropwise over 2 hours, and further 2 hours. Aged. Next, 0.25 parts of hydroquinone and 0.1 part of triethylamine were added, the temperature was raised to 130 ° C., 17.7 parts of glycidyl methacrylate was added, and the reaction was carried out for 2 hours. The obtained polymer has a solid content concentration.
It was 35% and the weight average molecular weight was 17 × 10 ⁴ (polymer (A-
1).

(Synthesis Example 2) Except that the monomer dropped in Synthesis Example 1 was changed to 128.5 parts of methyl methacrylate, 12.4 parts of ethyl acrylate, 9 parts of acrylic acid and 3.1 parts of glycooxyethyl methacrylate. Was reacted in the same manner as in Synthesis Example 1. The obtained polymer has a solid content concentration of 35.
%, The weight average molecular weight was 16 × 10 ⁴ (polymer (A-2)
). (Synthesis Example 3) 101.1 parts of butyl acetate were charged into a four-necked flask, heated to 92 ° C. in a nitrogen stream, and then, with stirring, 95 parts of methyl methacrylate and ethyl acrylate 11.
4 parts, 2-hydroxyethyl methacrylate 32.4 parts and butyl acetate 125 parts to tertiary butyl peroxy 2-.
A mixture in which 0.45 parts of ethyl hexanoate was previously dissolved was added dropwise over 3 hours. Then, the temperature was raised to 98 ° C. over 1 hour, and a mixture of 0.3 part of tert-butyl peroxy 2-ethylhexanoate in 90 parts of butyl acetate was added dropwise over 2 hours, and further 2 hours. Aged
After cooling to 80 ° C, 2.5 parts of dibutyltin dilaurate, 3 parts
26.3 parts of -isopropenyl-α, α-dimethylbenzylisocyanate was added and reacted for 2 hours. The obtained polymer had a solid concentration of 35% and a weight average molecular weight of 9 × 10 ⁴ . (Polymer (A-3)).

Examples and comparative examples were carried out as follows. First, the components were mixed in the proportions shown in Table 1, and the obtained compositions were each treated with ethyl acetate to give a viscosity of 70 seconds (Ford Cup No. 4
/ 20 ° C). These compositions were dried on a stainless steel substrate using a curtain flow coater to give a dry film thickness of 30 μm.
And was dried at 80 ° C. for 5 minutes to evaporate the diluent. Next, a transparent polyethylene film with a thickness of 50 μm was applied as a protective film, and exposed with ultraviolet rays from a high-pressure mercury lamp with a light intensity of 120 w / cm from a distance of 10 cm at a substrate speed of 5 m / min to obtain a first cured coating film. Got The obtained substrate was subjected to a 180 ° T-bending process and a blocking creep test. The cracks and peeling of the bent portion and the blocking and creep test were evaluated after heat curing. After removing the protective film from the substrate that was bent and the like, it was heated and cured at 180 ° C. for 30 minutes to obtain a final coating film. The final cured coating film was tested for hardness, stain resistance and impact resistance. The obtained results are shown in Table 2.

[0025]

[Table 1] Table 1 (Recipes) (Parts by weight of solid content) ─────────────────────────────────── Polymer (A) Crosslinking agent (B) Photopolymerization Others ──────────────── Initiator ⁽⁴⁾ component Example A-1 A-2 A-3 B-1 ⁽²⁾ B-2 ⁽³⁾ ────────────────────────────────── 1 30 30 1.4 2 30 30 1.4 3 30 30 1.4 5 ⁽⁵⁾ 4 30 30 1.4 5 30 30 1.4 2 ⁽⁶⁾ 6 30 30 1.4 7 30 15 15 1.4 5 ⁽⁵⁾ ───────────────── ────────────────── Comparative Example 1 30 1.4 30 ⁽⁷⁾ 2 30 30 3 30 15 15 5 ⁽⁵⁾ 4 30 ⁽¹⁾ 30 ────── ────────────────────────────

(1) Polyester polyol: Byron TP
00 5 (trade name, manufactured by Toyobo Co., Ltd.) Weight average molecular weight 10 × 10
⁴ (2) Melamine resin: Cymel 325 [trade name, manufactured by Mitsui Cyanamide Co., Ltd.] (3) Melamine acrylate resin: esramine [trade name,
Shin-Nakamura Chemical Co., Ltd.] (4) A mixture of 1 part of benzophenone and 0.4 part of Michler's ketone is used as a photopolymerization initiator. (5) Silica pigment (6) Urethane acrylate oligomer resin: Aronix M1100 (trade name, manufactured by Toagosei Co., Ltd.) (7) CH ₂ = CHCOOCH ₂ -C (CH ₂ OCOCH = CH ₂ ) ₂ CH ₂ OCOCH = CH ₂

[0027]

[Table 2] Table 2 [Test result] ───────────────────────────────── Blocking cliff fold Bending pencil Impact resistance Stain resistance Recovery rate ⁽⁸⁾ Workability ⁽⁹⁾ Hardness ⁽¹⁰⁾ Property ⁽¹¹⁾ Property ⁽¹²⁾ ─────────────────────────── ─────── Example 1 ○ Pass 5H ○ ○ 2 ◎ Pass 5 ~ 6H ○ ○ 3 ◎ Pass 5 ~ 6H ○ ○ 4 ○ Pass 5H ○ ○ 5 ◎ Pass 5H ◎ ○ 6 ○ Pass 5H ○ ○ 7 ◎ Pass 5-6H ○ ○ ───────────────────────────────── Comparative Example 1 ○ Failure 4H × ○ 2 × Fail 5H ○ ○ 3 ○ Fail 5H ○ ○ 4 × Fail 3H × △ ─────────────────────────────── ───

(8) Blocking / creep recovery rate: The coating film after UV curing was subjected to longitudinal deformation of 20, 30 and 50% of the film thickness, and applied to the coating film at 40 ° C. of 40 kg / cm ² . Pressure was applied for 8 hours to evaluate how much the resulting deformation had recovered after the final heat cure. ◎: Deformation disappeared even at 50% ○: Deformation disappeared at 30% △: Deformation disappeared at 20% ×: Deformation remained even at 20% (9) Bending workability: JIS-K-5400, After pre-bending with a bending vise specified in Section 8.1 (bending resistance), crush it with a vise and observe the state of the coating at the bend R with a 30 times magnifying glass to ensure that the coating does not crack. Was accepted, and those with cracks were rejected. (10) Pencil hardness: JIS-K-5400, 8.4.2 using Mitsubishi Uni-Pencil
Tested according to paragraph. (11) Impact resistance: Using JIS-K-5400, Item 8.3.2 DuPont impact tester, a 300 g weight is dropped onto the surface of a coating film on which a hemispherical die with a radius of 6.35 mm is placed. ◎: 20 cm or more without any abnormality ○: 10 cm without cracks ×: 10 cm with cracks

(12) Contamination resistance: Draw on the surface of the coating film with a magic ink (manufactured by Yoko Uchida) at 20 ° C., leave it for 24 hours, wipe the ethanol with a gauze cloth, wipe it off, and evaluate after the line. ◯: No trace remains at all Δ: Trace remains slightly ×: Trace remains clearly As is clear from the test results of Table 2, the coating films of the coated metal sheets of Examples 1 to 7 obtained by the method of the present invention Had good workability, high hardness, and excellent stain resistance and impact resistance.
On the other hand, Comparative Example 1 using a coating material containing no cross-linking agent had poor processability and impact resistance, and had a hardness lower than that of the present invention. It is considered that this is because the coating film is only polymerized and cured by irradiation of ultraviolet rays and there is no crosslinking reaction between the polymer (A) and the crosslinking agent (B). Further, although the ultraviolet rays were used as the active energy rays, Comparative Examples 2, 3 and 4 in which the paints containing no photopolymerization initiator were used had poor processability. It is considered that this is because the coating is only cured by the crosslinking reaction between the polymer (A) and the crosslinking agent (B), and is not cured by ultraviolet irradiation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B05D 7/24 R 8720-4D 302 S 8720-4D

Claims (7)

[Claims] 1. A method for producing a coated metal plate product, comprising: (I) a metal plate having (A) a polymer having a polymerizable double bond and a crosslinkable functional group; and (B) the functional group. A process of applying a coating material containing a cross-linking agent that reacts by heating and irradiating with active energy rays (excluding ultraviolet rays) to form a primary cured coating film, (II) Metal on which a primary cured coating film is formed A method for producing a coated metal sheet product, which comprises the step of forming a sheet, and (III) baking the formed metal sheet to completely cure the primary cured coating film. 2. The method for producing a coated metal sheet product according to claim 1, wherein the functional group of the polymer (A) is a hydroxyl group, and the crosslinking agent (B) is an aminoplast compound. 3. The aminoplast compound is represented by the following general formula:
The method for producing a coated metal sheet product according to claim 2, which is a compound represented by (i) or a condensate thereof: Wherein R _{is, -H, -CH 2 OH, -CH} 2 OCH 3, -CH 2 OC
_{4 H 9, -CH 2 OC (} O) CH = CH 2, -CH 2 OC (O) C (CH 3) = CH 2, -CH 2
NHC (O) CH = CH ₂ or _{-CH 2 NHC (O) C (} CH 3) = a one CH _2, R is also each have different and also may be the same. ] 4. A method for producing a coated metal plate product, comprising: (I) a metal plate having (A) a polymer having a polymerizable double bond and a crosslinkable functional group; and (B) the functional group. A step of applying a coating material containing a crosslinking agent that reacts by heating, and (c) a photopolymerization initiator, and irradiating ultraviolet rays to form a primary cured coating film, (II) forming a primary cured coating film A method for producing a coated metal sheet product, which comprises the step of forming a formed metal sheet, and (III) baking the formed metal sheet to completely cure the primary cured coating film. 5. The method for producing a coated metal sheet product according to claim 4, wherein the functional group of the polymer (A) is a hydroxyl group and the crosslinking agent (B) is an aminoplast compound. 6. The aminoplast compound is represented by the following general formula:
The method for producing a coated metal sheet product according to claim 5, which is a compound represented by (i) or a condensate thereof: Wherein R _{is, -H, -CH 2 OH, -CH} 2 OCH 3, -CH 2 OC
_{4 H 9, -CH 2 OC (} O) CH = CH 2, -CH 2 OC (O) C (CH 3) = CH 2, -CH 2
NHC (O) CH = CH ₂ or _{-CH 2 NHC (O) C (} CH 3) = a one CH _2, R is also each have different and also may be the same. ] 7. The protective film is laminated on the surface of a painted metal plate before or after the irradiation with the active energy ray, and the protective film is removed before baking. The method for producing a coated metal plate product according to item 1.