JP2003211076A - Method for forming matte coating film and matte coated metallic sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which reduces the difference in the extent of formation of crepe by a fluctuation in film thicknesses and makes it possible to obtain a matte coating film by the uniform crepe. <P>SOLUTION: The method for forming the matte coating film comprises applying a primer coating material (A) containing a secondary amine and/or ternary amine of a boiling point 30 to 300°C at 1 to 50 pts.wt. per 100 pts.wt. resin solid content in the coating material and drying the coating film by heating at need, then applying a finish coating material (B) consisting of a hydroxy group-containing organic resin, an amino resin and an acid catalyst on the primer coating film and curing the coating film by heating. <P>COPYRIGHT: (C)2003,JPO

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 high-quality matte coating film having no gloss unevenness. It also relates to a matte coated metal plate using the method.

[0002]

2. Description of the Related Art In recent years, various innovations have been made in coating compositions and coating methods due to the diversification of tastes and taste preferences of consumers. Especially in the field of pre-coat painting such as home appliances, container processing, building materials, and outer surface of can packaging.
A low-gloss coating film with a gloss (60 ° gloss) of 10 or less has been demanded in the market, and a method of incorporating a large amount of fine silica powder into a paint, mica, alumina,
A method of blending silica, talc, etc. to reduce gloss is generally performed.

However, in these methods, since the light transmission of fine silica powder and extender pigment used for reducing gloss is large, photodegradation is easily received inside the coating film, and thus gloss is reduced by these methods. The paint film thus formed has a large discoloration and fading in the outdoors and is likely to cause chalking. Further, a coating film containing a large amount of fine silica powder or an extender pigment has a relatively small resin content in the coating film, and the pigment is not sufficiently covered with the resin to increase the exposed portion of the pigment. If the coating is strongly rubbed with gauze, the "color fading" phenomenon that the color is transferred to the gauze tends to occur.

As a method for solving these problems, a shrink paint prepared by blending a methylated melamine resin and a tertiary amine block sulfonic acid with a polyester resin (JP-A-62-62).
No. 174276); a shrink paint prepared by blending an acrylic resin with a methylated melamine resin, crosslinked organic fine particles and a tertiary amine block sulfonic acid (JP-A-62-20517).
No. 3); a matting method by causing shrinkage in a coating film, such as a shrinking paint obtained by blending a low-nuclear melamine resin and a secondary amine block sulfonic acid in a polyester resin (Japanese Patent Laid-Open No. 2-219881). .

All of the methods for causing shrinkage of these coating films are systems using an amine-blocked acid catalyst in the top coating composition, and when baking and curing the coating film with hot air, the surface of the coating film exposed to hot air is exposed. The surface of the coating film is shrunk by first curing the coating film surface by utilizing the removal of the amine block from the acid catalyst and then curing and shrinking the interior of the coating film later.

However, since these shrink paints make use of the difference in the curing speed between the surface and the interior of the coating film, the degree of shrinkage varies depending on the coating film thickness, and a thin film provides a sufficient matting effect. If it is not applied or if the coating film thickness is not uniform, gloss unevenness occurs.

An object of the present invention is to provide a method for obtaining a uniform matte coating film with a small difference in the degree of shrinkage due to variations in film thickness, and to provide a matte-coated metal sheet using the method. That is.

[0008]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that an undercoating paint containing an amine compound is applied first, and an overcoating paint having an acid catalyst is applied thereon. The inventors have found that a matte coating film which is extremely uniform and has no unevenness can be obtained by applying and baking it, and has completed the present invention.

Thus, the present invention contains 1 to 50 parts by weight of a secondary amine and / or a tertiary amine having a boiling point of 30 to 300 ° C. on the basis of 100 parts by weight of the resin solid content in the coating material. The undercoating coating composition (A) is applied and, if necessary, dried by heating, and then an overcoating coating composition (B) comprising a hydroxyl group-containing organic resin, an amino resin and an acid catalyst on the undercoating coating film.
A method for forming a matte coating film is provided, which comprises coating, heating and curing.

The present invention also provides a matte-coated metal sheet using the above-described method for forming a matte coating film.

The present invention will be described in more detail below.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an amine-containing undercoat paint (A) is applied onto a material and, if necessary, dried by heating, and then a hydroxyl group-containing organic resin or melamine is applied onto the undercoat film. This is a method for forming a matte coating film by applying a topcoat paint (B) comprising a resin and an acid catalyst, heating and curing.

According to the method of the present invention, when the top coat is heated and cured, the lower portion of the top coat which is in contact with the bottom coat is an amine that migrates from the bottom coat, so that the acid catalyst does not work effectively in the initial stage of baking. Therefore, the upper part (surface) of the top coat film is cured first, and thereafter the lower part of the coat film is cured and shrunk, so that the film shrinks and the gloss of the film disappears. Compared with the conventional method in which an amine-blocked acid catalyst is added to the topcoat to cause shrinkage, the method of the present invention can cause shrinkage more reliably, and shrinks even if the topcoat film is thin. Can be stably formed, and the size of shrinkage is constant even if the film thickness of the top coating film varies, and a coating film having no gloss unevenness can be formed.

The undercoat paint (A) in the present invention
Is a paint for a coating film formed immediately below the top coating film formed on the uppermost layer of the coating film, and in the case of the two-coat specification, it means a primer directly coated on a material such as metal. When it has a coating layer of 3 coats or more, it means the coating material for the layer immediately below the top coating layer which causes shrinkage.

Undercoat paint (A) The undercoat paint (A) used in the present invention is a conventional undercoat paint such as an epoxy or polyester base having a boiling point of 30.
To 50 ° C. secondary amine and / or tertiary amine to 1 to 50 relative to 100 parts by weight of resin solid content in the undercoat paint.
It can be obtained by adding parts by weight, preferably 5 to 20 parts by weight. If the amount of amine added is too small, it is not possible to obtain a stable shrink pattern, and if it is too large, curing of the topcoat paint is impaired and the coating properties such as hardness and adhesion are reduced.

The resin used in the undercoat paint can be used without particular limitation as long as it is a resin capable of forming a coating film. For example, at least one selected from polyester resin, epoxy resin, acrylic resin, fluororesin and the like. And a mixture of these resins and a curing agent.

The coating film forming resin does not need to be a heat-crosslinking system in particular, but a heat-crosslinking system is generally superior in corrosion resistance, adhesion, coating film hardness and the like. Hydroxyl group-containing polyester resin (a) and epoxy resin (b)
At least one organic resin selected from the following and a curing agent (c)
A mixture with and can be preferably used.

Examples of the hydroxyl group-containing polyester resin (a) include oil-free polyester resins, oil-modified alkyd resins, and modified products of these resins, such as urethane-modified polyester resins, urethane-modified alkyd resins, epoxy-modified polyester resins, and acrylics. Modified polyester resins and the like are included. The hydroxyl group-containing polyester resin has a number average molecular weight of 1,500 to 35,000, preferably 2,000 to 25,000, and a glass transition temperature (T
g point) 10 to 100 ° C, preferably 20 ° C to 80 ° C, hydroxyl value 2 to 100 mgKOH / g, preferably 5 to 80
Those with mg KOH / g are preferred.

The glass transition temperature (Tg) of the above resin is measured by differential scanning calorimetry (DSC), and the number average molecular weight is measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. It is a thing.

The oil-free polyester resin comprises an esterified product of a polybasic acid component and a polyhydric alcohol component. As the polybasic acid component, for example, one or more selected from phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, etc. Dibasic acids and lower alkyl esterified products of these acids are mainly used, and if necessary, monobasic acids such as benzoic acid, crotonic acid, and pt-butylbenzoic acid, trimellitic anhydride, methylcyclohexene tricarboxylic acid. , A tribasic or higher polybasic acid such as pyromellitic dianhydride is used in combination. Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol,
Dihydric alcohols such as neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol are mainly used, and further, glycerin, trimethylolethane, trimethylolpropane, penta, etc. are used as necessary. A trihydric or higher polyhydric alcohol such as erythritol can be used in combination. These polyhydric alcohols can be used alone or in admixture of two or more. The esterification or transesterification reaction of both components can be carried out by a method known per se. As the acid component, isophthalic acid, terephthalic acid,
And lower alkyl esterified products of these acids are particularly preferable.

The alkyd resin is obtained by reacting an oil fatty acid by a method known per se in addition to the acid component and the alcohol component of the oil-free polyester resin, and examples of the oil fatty acid include coconut oil fatty acid and large oil fatty acid. Examples include soybean oil fatty acid, linseed oil fatty acid, safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, tung oil fatty acid and the like. The oil length of the alkyd resin is preferably 30% or less, more preferably about 5 to 20%.

As the urethane-modified polyester resin,
The oil-free polyester resin, or a low molecular weight oil-free polyester resin obtained by reacting an acid component and an alcohol component used in the production of the oil-free polyester resin, is reacted with a polyisocyanate compound by a method known per se. Some of them are the ones. Further, the urethane-modified alkyd resin is obtained by reacting the alkyd resin, or a low molecular weight alkyd resin obtained by reacting each component used in the production of the alkyd resin, with a polyisocyanate compound by a method known per se. Things are included. Examples of the polyisocyanate compound that can be used when producing the urethane-modified polyester resin and the urethane-modified alkyd resin include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate,
4,4'-methylenebis (cyclohexyl isocyanate), 2,4,6-triisocyanatotoluene and the like can be mentioned. As the urethane-modified resin, generally, those having a modification degree such that the amount of the polyisocyanate compound forming the urethane-modified resin is 30% by weight or less based on the urethane-modified resin can be preferably used.

As the epoxy-modified polyester resin,
Using a polyester resin produced from each component used in the production of the polyester resin, a reaction product of a carboxyl group of this resin and an epoxy group-containing resin, a hydroxyl group in the polyester resin and a hydroxyl group in the epoxy resin polyisocyanate A reaction product obtained by a reaction such as addition, condensation or grafting of a polyester resin and an epoxy resin, such as a product bonded via a compound, can be mentioned.
The degree of modification in such an epoxy-modified polyester resin is generally preferably such that the amount of the epoxy resin is 0.1 to 30% by weight based on the epoxy-modified polyester resin.

As the acrylic modified polyester resin,
Using a polyester resin produced from each component used in the production of the above polyester resin, a group having reactivity with these groups in the carboxyl group or hydroxyl group of the resin, for example, an acrylic resin containing a carboxyl group, a hydroxyl group or an epoxy group. And a reaction product obtained by graft-polymerizing (meth) acrylic acid or (meth) acrylic acid ester with a polyester resin using a peroxide-based polymerization initiator. The degree of modification in such an acrylic modified polyester resin is generally
The amount of the acrylic resin is preferably 0.1 to 50% by weight based on the acrylic modified polyester resin.

Among the polyester resins described above, the oil-free polyester resin and the epoxy-modified polyester resin are particularly preferable from the viewpoint of the balance of processability and corrosion resistance.

Epoxy resin (b) suitable as the coating film forming resin is bisphenol type epoxy resin or novolac type epoxy resin; modified epoxy obtained by reacting various modifying agents with epoxy groups or hydroxyl groups in these epoxy resins. Resin can be mentioned. In the production of the modified epoxy resin, the timing of modification with the modifying agent is not particularly limited, and the modification may be performed at an intermediate stage of the epoxy resin production or at a final stage of the epoxy resin production.

The above-mentioned bisphenol type epoxy resin is, for example, a resin obtained by condensing epichlorohydrin and bisphenol up to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, epichlorohydrin and bisphenol, and if necessary, alkali It may be any resin obtained by condensing into a low molecular weight epoxy resin in the presence of a catalyst such as a catalyst and subjecting the low molecular weight epoxy resin and bisphenol to a polyaddition reaction.

Examples of the bisphenol include bis (4-
Hydroxyphenyl) methane [bisphenol F],
1,1-bis (4-hydroxyphenyl) ethane, 2,
2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-) Hydroxy-tert-butyl-phenyl) -2,2-propane, p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4'-dihydroxybenzophenone, Examples thereof include bis (2-hydroxynaphthyl) methane, and among them, bisphenol A and bisphenol F are preferably used. The above bisphenols can be used alone or as a mixture of two or more.

Commercially available bisphenol type epoxy resins include, for example, Epicoat 828, 812, 815, 820, 834, 834, 1001, 1004, 1007, 1009 and 1009 manufactured by Yuka Shell Epoxy Co., Ltd. 1
010; Araldite AER6099 manufactured by Asahi Ciba Co., Ltd., and Epomic R-309 manufactured by Mitsui Chemicals, Inc., and the like.

The novolac type epoxy resin which can be used as the epoxy resin (b) includes, for example, phenol novolac type epoxy resin, cresol novolac type epoxy resin, phenol glyoxal type epoxy resin having many epoxy groups in the molecule, and the like. Various novolac type epoxy resins can be mentioned.

As the modified epoxy resin, for example, an epoxy ester resin obtained by reacting the above bisphenol type epoxy resin or novolac type epoxy resin with a drying oil fatty acid; a polymerizable unsaturated monomer component containing acrylic acid, methacrylic acid or the like. An epoxy acrylate resin reacted with an isocyanate compound; a urethane-modified epoxy resin reacted with an isocyanate compound; an amine compound is reacted with an epoxy group in the bisphenol type epoxy resin, the novolac type epoxy resin, or the various modified epoxy resins to give an amino group or Examples thereof include amine-modified epoxy resin obtained by introducing a quaternary ammonium salt.

The curing agent (c) may be used without particular limitation as long as it can be cured by reacting with the hydroxyl group-containing polyester resin (a) and / or the epoxy resin (b) by heating. However, among them, at least one curing agent selected from amino resins and blocked polyisocyanate compounds can be preferably used.

Examples of the amino resin include methylol amino resins obtained by the reaction of an aldehyde with an amino component such as melamine, urea, benzoguanamine, acetogramamine, sterogtanamine, spiroguanamine, and dicyandiamide. Examples of the aldehyde used in the above reaction include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, the above methylolated amino resin etherified with a suitable alcohol can also be used as the amino resin. Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

The blocked polyisocyanate compound that can be used as the curing agent (c) is a compound obtained by blocking the free isocyanate group of the polyisocyanate compound with a blocking agent.

Examples of the polyisocyanate compound before blocking are aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate; cyclic aliphatic diisocyanates such as hydrogenated xylylene diisocyanate or isophorone diisocyanate; tolylene diisocyanate. Alternatively, an organic diisocyanate itself such as an aromatic diisocyanate such as 4,4′-diphenylmethane diisocyanate, or an adduct of each of these organic diisocyanates with a polyhydric alcohol, a low molecular weight polyester resin or water, or each of the above-mentioned organic compounds Examples thereof include cyclized polymers of diisocyanates, and isocyanate / biuret.

Examples of the blocking agent for blocking the isocyanate group include phenols such as phenol, cresol and xylenol; ε-caprolactam; δ-
Lactams such as valerolactam and γ-butyrolactam;
Alcohol systems such as methanol, ethanol, n-, i- or t-butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol; formamidoxime, acetaldoxime, An oxime-based blocking agent such as acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexane oxime; an active methylene-based blocking agent such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, and acetylacetone can be preferably used. By mixing the polyisocyanate compound and the blocking agent, the free isocyanate group of the polyisocyanate compound can be easily blocked.

The mixing ratio of the hydroxyl group-containing polyester resin (a), the epoxy resin (b) and the curing agent (c) is such that the total solid content of the components (a), (b) and (c) is 10%.
Based on 0 parts by weight, the total amount of the polyester resin (a) and the epoxy resin (b) is 55 to 95 parts by weight, and further 6
0 to 95 parts by weight, and it is preferable that the curing agent (c) is in the range of 5 to 45 parts by weight, further 5 to 40 parts by weight from the viewpoint of corrosion resistance, water resistance, processability, curability and the like. Is.

The amine added to the undercoat paint is a secondary amine and / or a tertiary amine having a boiling point of 30 to 300 ° C. Examples of the secondary amine compound include diethylamine, diisopropylamine, di-n-propylamine, diallylamine, diamylamine, di-n-butylamine, diisobutylamine, disec-butylamine,
N-ethyl-1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 4-pipecoline, 2,4-, 2,
5- or 3,5-lupetidine, dimethyloxazolidine, 3-piperidinemethanol and the like can be mentioned. Examples of the tertiary amine compound include triethylamine, tributylamine, N-methylmorpholine,
N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N, N ', N'-tetramethyl-1,2-diaminoethane, N, N, N', N '
-Tetramethyl-1,3-diaminopropane, N-methylpiperidine, 4-ethylpiperidine, pyridine and the like can be mentioned. Further, a compound having both a secondary amino group and a tertiary amino group such as N-methylpiperazine can also be used as the secondary or tertiary amine compound.

In the present invention, in addition to the above-mentioned components, the undercoating material may be a rust preventive pigment, a coloring pigment such as titanium white, an extender pigment such as clay, talc, calcium carbonate or barium sulfate, a defoaming agent, a coated surface, if necessary. A regulator, an anti-settling agent, a pigment dispersant, an organic solvent and the like can be contained.

Examples of the rust preventive pigment include strontium chromate, calcium chromate, zinc chromate,
Chromium-based rust preventive pigments such as zinc potassium chromate and barium chromate; ion exchange silica such as calcium ion exchange silica, zinc phosphate, zinc phosphite, aluminum phosphite, calcium phosphite, aluminum tripolyphosphate, zinc molybdate, oil absorption 30-200ml / 100
g, preferably in the range of 60 to 180 ml / 100 g and having a pore volume of 0.05 to 1.2 ml / g, preferably in the range of 0.2 to 1.0 ml / g, a small oil absorption silica fine powder. Non-chromium rust preventive pigments such as

The undercoat coating film obtained from the undercoat coating composition (A) of the present invention has a glass transition temperature of 40 to 100 ° C., preferably 50 to 85 ° C. in order to improve acid resistance, corrosion resistance and processability. It is preferable from the point.

In the present invention, the glass transition temperature of the coating film is DINAMICVISCOELASTOMETER.
Model VIBRON (dynamic viscoelastometer model vibron) DDV-II EA type (manufactured by Toyo Baldwin Co., Ltd., automatic dynamic viscoelasticity measuring instrument) was used to measure temperature dispersion at a frequency of 110 Hz, tan.
It is the maximum temperature obtained from the change of δ.

Topcoat Paint (B) The topcoat paint used in the present invention comprises a hydroxyl group-containing organic resin, an amino resin and an acid catalyst.

Examples of the hydroxyl group-containing organic resin include hydroxyl group-containing polyester resin, acrylic resin, fluororesin, silicone polyester resin, and the like. Among them, the hydroxyl group-containing polyester resin is the processability of the coating film. It is preferable in terms of adhesion, etc. The hydroxyl value of the hydroxyl group-containing organic resin is 5 to 110 mg.
KOH / g, preferably in the range of 20-100 mg KOH / g is suitable for stable formation of shrinkage.

Examples of the amino resin include methylol amino resins obtained by the reaction of an aldehyde with an amino component such as melamine, urea, benzoguanamine, acetogramamine, sterogtanamine, spiroguanamine, and dicyandiamide. Examples of the aldehyde used in the above reaction include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Further, the above methylolated amino resin etherified with a suitable alcohol can also be used as the amino resin. Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

As the amino resin, an alkyl etherified methylolated amino resin, particularly a methyl etherified melamine resin, or a mixed etherified melamine resin of methyl ether and butyl ether can be preferably used, and the shrink pattern stability is improved. From the standpoint, the low-nuclear methyl etherified melamine resin is particularly excellent.

The above-mentioned low-nuclear methyl etherified melamine resin is a low-nuclear melamine resin having a methoxy group by methylation, and a melamine resin containing 40% by weight or more of hexamethoxymethylmelamine mononuclear is particularly preferable.

Examples of commercially available methyl etherified melamine resins include Cymel 300, 303, and 37.
0, 232, 235, 238, 272 (above,
Both are manufactured by Mitsui Cyanamid Co., Ltd.), Nikarac MW3
0, the same MW22A (all of which are manufactured by Sanwa Chemical Co., Ltd.), Sumimar M100 (manufactured by Sumitomo Chemical Co., Ltd.), Regimins 747, 745, and 755 (all of which are manufactured by Monsanto Co., Ltd.).

The acid catalyst is a catalyst that accelerates the curing reaction between the hydroxyl group-containing organic resin and the amino resin, and for example, a sulfonic acid compound is preferably used. Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and the like.
Among them, p-toluenesulfonic acid and dodecylbenzenesulfonic acid are preferable.

In the above acid catalyst, a part or all of the acid may be neutralized with a secondary amine or a tertiary amine,
From the viewpoint of storage stability of the topcoat paint, it is preferably neutralized. Further, even if the topcoat paint alone is designed to generate shrinkage, it can be used, but in that case, it is preferable to adjust the baking temperature or the baking time so that the coating film does not become insufficiently cured.

The topcoat paint (B) is blended in such a manner that 3 parts by weight of the amino resin is added to 100 parts by weight (solid content) of the hydroxyl group-containing organic resin.
50 parts by weight (solid content), preferably 5 to 30 parts by weight (solid content), and an acid catalyst as an active ingredient amount of 0.1 per 100 parts by weight of the total solid content of the hydroxyl group-containing organic resin and the amino resin. What is contained in the range of 5 to 5 parts by weight, preferably 0.5 to 3 parts by weight is suitable.

In addition to the above resin component and acid catalyst, the top coating material (B) may be an inorganic pigment, an organic pigment, a bright pigment, an organic resin fine particle, an organic resin fiber, glass beads, an organic solvent or a defoaming agent, if necessary. Conventionally known coating materials such as an agent, a coating surface modifier, and a lubricity imparting agent can be contained.

The above-mentioned organic resin fine particles, organic resin fibers, and glass beads stabilize the shrinkage pattern of the topcoat coating film formed from the topcoat paint, adjust the size of the pattern of the shrinkage pattern, and impart design characteristics. It is mixed for the purpose such as.

As the bright pigment, mica-like iron oxide powder, pearl-like mica powder, aluminum powder, copper powder,
Examples of the powder include stainless powder, gold powder, and other metal powders, which exhibit a unique design property when the top coating is clear.

Coating Method Materials used in the present invention include cold rolled steel sheets, hot-dip galvanized steel sheets, electrogalvanized steel sheets, alloy-plated steel sheets, aluminum sheets, stainless steel sheets, copper sheets, copper-plated steel sheets, tin-plated steel sheets and other metals. It can be applied to plastics, wood, cement, etc. As a painting method,
Curtain coating, roll coating, dip coating and spray coating are possible.

In the case of coating metals, the metal surface as the material to be coated may be coated as it is if it is not contaminated with contaminants such as oil, but it improves the adhesion to the coating film and the corrosion resistance. Therefore, it is desirable to perform a known metal surface treatment. Examples of these known surface treatment methods include phosphate surface treatment, chromate surface treatment, and coating treatment with a chromic acid coating agent.

The coating film thickness of the undercoat paint (A) and the topcoat paint (B) is not particularly limited, but the dry film thickness of the undercoat paint (A) is usually 1 to 20 μm, and particularly preferably 3 to 15 μm. Yes, the top coat (B) is usually 10 to 10 in dry film thickness.
It is preferably in the range of 50 μm, particularly 15 to 30 μm.

As the method of forming the coating film, after the undercoat paint (A) is applied, for example, a method of applying the topcoat paint by wet-on-wet with a spray, a curtain flow coater, a die coater, etc. and baking it, and a undercoat paint There is a method in which (A) is applied, heated and dried, and then an overcoat paint is applied and baked, which may be selected according to the application. In the case of the latter method, it is preferable to set the drying conditions of the undercoat paint to as low a temperature as possible without causing problems in coating workability so that the amine sufficiently remains in the undercoat paint film. For example, in the precoat coating field, a maximum material reaching temperature (PMT) of 60 to 200 ° C. for about 10 to 60 seconds is suitable.

The topcoat paint (B) may be baked at the temperature and time conventionally used. For example, in the field of precoat coating, the maximum material temperature (PMT) is 170 to 260 ° C. and the temperature is 15 to 90. Seconds are preferred. However, when using a high-boiling amine or when the amount of amine added is large and the curability of the coating film is not sufficient, increase the baking temperature and / or extend the baking time while checking the curability of the coating film. Need to be adjusted.

Since the matte coating material obtained as described above has a high design property, it is suitable for the field of precoat coating such as home appliances, processing of articles, building materials, and outer surfaces of can packaging.

[0061]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, "part" and "%"
All are based on weight.

Synthesis of Polyester Resin Synthesis Example 1 740 parts of phthalic anhydride in a reaction tank using a conventional polyester resin production apparatus equipped with a heating device, a stirrer, a reflux device, a water separator, a rectification column, a thermometer, etc. 498 parts of isophthalic acid,
145 parts of adipic acid, 735 parts of neopentyl glycol and 236 parts of 1.6-hexanediol were charged and heated. After the raw materials are melted, stirring is started and the reaction temperature is set to 230.
The condensate water produced by heating to 230 ° C. for 2 hours was distilled out of the system through a rectification column. Next, 90 parts of xylol was added to the reaction tank and the reaction was continued by switching to the solvent condensation method. When the acid value reached 5 mgKOH / g, the reaction was terminated and cooled. After cooling, 1414 parts of xylol was added to obtain a polyester resin solution R1 having a solid content of 60%.
The obtained resin had a hydroxyl value of 79 mgKOH / g and a number average molecular weight of about 1,300.

Synthesis Example 2 In Synthesis Example 1, the raw material composition initially charged in the reaction vessel was 592 parts phthalic anhydride, 747 parts isophthalic acid, 145 parts adipic acid, 735 parts neopentyl glycol, and 1.6 parts.
-The same operation was performed except that the composition was 295 parts of hexanediol and 68 parts of trimethylolpropane, and the solid content was 6
A 0% polyester resin solution R2 was obtained. The obtained resin has a hydroxyl value of 42 mgKOH / g and a number average molecular weight of about 2,
It was 100.

Production of Topcoat Paint Production Example 1 100 parts of polyester resin solution R1 having a solid content of 60%,
A mixture of 10 parts of xylol, 70 parts of titanium white, and 5 parts of phthalocyanine blue was dispersed with a shaker until the tub became 10 microns. Then, 42 parts of this polyester resin solution R1, 15 parts of Cymel 303 (manufactured by Mitsui Cyanamid Co., low-nuclear methylated melamine resin, solid content: about 100%), 0.5 parts of dinonylnaphthalenedisulfonic acid and Syloid were used. 8 parts of 74 (manufactured by Fuji Devison Co., Ltd., amorphous silica fine powder, average particle size of about 6 μm) and 5 parts of polyacrylonitrile fiber (average diameter: about 25 μm, average length: about 0.5 mm) were added and stirred uniformly. , Solvesso 1
A viscosity of 80 seconds (Ford cup # 4, 25 with a 1: 1 mixed solvent of 50 (high boiling point petroleum solvent manufactured by Esso Oil Co., Ltd.) and ethylene glycol monoethyl ether acetate.
C.) to obtain coating material T1.

Production Example 2 100 parts of polyester resin solution R2 having a solid content of 60%,
A mixture of 10 parts of xylol, 70 parts of titanium white, and 5 parts of phthalocyanine blue was dispersed with a shaker until the tub became 10 microns. Then, 42 parts of polyester resin solution R2, 15 parts of Cymel 303 (manufactured by Mitsui Cyanamid Co., low-nuclear-body methylated melamine resin, solid content: about 100%), Naikuure 5225 (Dodecyl, manufactured by King Industries, USA) were added. 1 part of a secondary amine neutralized product of benzenesulfonic acid) and Syloid 74 (manufactured by Fuji Devison Co., Ltd., amorphous silica fine powder, average particle size of about 6 μ)
m) Add 10 parts, stir evenly, Solvesso 150
The viscosity was adjusted to 80 seconds (Ford cup # 4, 25 ° C.) with a 1: 1 mixed solvent of (Esso Petroleum Co., Ltd., high boiling point petroleum solvent) and ethylene glycol monoethyl ether acetate to obtain a coating T2.

Production Example 3 (for Comparative Example) A coating material T3 was obtained by adding 1.5 parts of di-n-butylamine to 100 parts of the coating material T2 obtained in Production Example 2.

Preparation of Test Coated Plates Examples 1 to 16 and Comparative Examples 1 to 5 Chromate-treated galvalume steel plates having a plate thickness of 0.35 mm were coated with the amine-added undercoat paint shown in Table 1 below by a bar coater. Baking was performed for a second. Further, apply a top coat paint on the undercoat coat with a bar coater, and
Printing was performed for a second. The types of the undercoat and topcoat paints, the PMT (maximum temperature reached by the material, ° C) during baking, and the dry film thickness are as shown in Table 1 below.

Coating Film Performance Test The coating film performance of each test coated plate obtained above was evaluated according to the test method shown below. The results are shown in Table 1 below.

Appearance of coating film: Whether or not a shrinkage pattern was uniformly generated on the coated surface was visually evaluated according to the following criteria. ◯: A uniform and clear shrink pattern is seen on the entire coated surface. Δ: The shrinkage pattern is non-uniform and looks uneven. X: Almost no shrinkage is observed on the coated surface.

Pencil hardness: JIS K-for each test plate
5400 84.2 (1990), a pencil scratching test was performed, and the following criteria were evaluated. ◯: 2H or more. Δ: HB to H. X: B or less.

Solvent resistance: Approximately 1 kg / g on the coated surface with gauze impregnated with methyl ethyl ketone in a room at 20 ° C.
A load of cm ² was applied to reciprocate between lengths of about 5 cm. The number of times of reciprocation until the base was visible was evaluated according to the following criteria. ◯: 50 times or more. Δ: 30 to 49 times. X: 29 times or less.

Adhesion: JIS K-54008.5.2.
(1990) According to the cross-tape method, 11 straight lines that are orthogonal to each other are drawn at 1 mm intervals so that the coating film surface of the test plate reaches the substrate with a cutter knife.
100 squares of 1 mm x 1 mm were created. A cellophane adhesive tape was brought into close contact with the surface, and the degree of peeling of the squares when the tape was rapidly peeled off was observed and evaluated according to the following criteria. ◯: No peeling of the coating film is observed. . Δ: The coating film peeled slightly, but 90 or more squares remained. X: The coating film peeled considerably and the number of remaining squares was less than 90.

[0073]

[Table 1]

Each note (* 1 to 3) in Table 1 is as follows. (* 1) Paint type: The contents of the undercoat paint type indicated by each symbol are as follows: P1: KP color 8000 primer, manufactured by Kansai Paint Co., Ltd., trade name, epoxy / polyisocyanate based undercoat paint. P2: KP color 8625 primer, manufactured by Kansai Paint Co., Ltd., trade name, polyester / melamine based undercoat paint. (* 2) Additive amine species: The content of amine species indicated by each symbol is as follows. A1: Trinormal butylamine, boiling point 212 ° C. A2: Dinormal butylamine, boiling point 159 ° C. A3: Diisobutylamine, boiling point 137 ° C. A4: Triphenylamine, boiling point 365 ° C. (* 3) Amount of added amine: Resin solid content in undercoat paint 10
Addition weight part of amine to 0 weight part.

[0075]

EFFECTS OF THE INVENTION By using the method for forming a matte coating film of the present invention, it is possible to obtain a uniform and high-quality matte coating film, which is particularly useful for precoating of household appliances, container processing, building materials, outer surfaces of can packaging, etc. It is extremely useful in the coating field.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shingo Amagi             Seki, 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Prefecture             West Paint Co., Ltd. F-term (reference) 4D075 AE03 AE08 BB26Z BB92Z                       BB93Z BB95Z CB02 DA06                       DB01 DC01 DC10 DC18 DC38                       DC42 EA07 EA19 EB32 EB33                       EB35 EB55 EB56 EC37 EC60                 4F100 AB01A AB03 AK35C AK41C                       AL05C AT00A BA03 BA07                       CA02C CC01B CC03C EJ08                       EJ42 EJ65B GB07 GB16                       GB48 JL11 JN26

Claims (7)

[Claims] 1. A resin solid content of 100 in a paint on a material.
After applying a base coating composition (A) containing 1 to 50 parts by weight of a secondary amine and / or a tertiary amine having a boiling point of 30 to 300 ° C. to parts by weight, and heating and drying if necessary,
A method for forming a matte coating film, which comprises applying an upper coating composition (B) comprising a hydroxyl group-containing organic resin, an amino resin and an acid catalyst on the undercoating coating film and heating and curing the same. 2. The method for forming a matte coating film according to claim 1, wherein the hydroxyl group-containing organic resin is a hydroxyl group-containing polyester resin. 3. The hydroxyl value of the hydroxyl group-containing organic resin is 5 to 1
The method for forming a matte coating film according to claim 1 or 2, which is in the range of 10 mgKOH / g. 4. The method for forming a matte coating film according to any one of claims 1 to 3, wherein the amino resin is a low molecular weight methyl etherified melamine resin. 5. The topcoat paint (B) comprises 3 to 50 amino resins based on 100 parts by weight of hydroxyl group-containing organic resin (solid content).
3. The acid catalyst is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total solid content of the hydroxyl group-containing polyester resin and the amino resin.
5. The method for forming a matte coating film according to any one of 4 to 4. 6. The coating film thickness of the undercoat paint (A) is in the range of 3 to 15 μm in terms of dry film thickness, and the coating film thickness of the topcoat paint (B) is in the range of in the range of 10 to 50 μm in terms of dry film thickness. The method for forming a matte coating film according to claim 1. 7. A resin solid content of 100 in a paint on a metal plate.
An undercoat paint (A) containing 1 to 50 parts by weight of a secondary amine and / or a tertiary amine having a boiling point of 30 to 300 ° C. with respect to parts by weight so that the dry film thickness is 3 to 15 μm Maximum temperature reached (PMT) 60-200 ℃
After heating and drying for 10 to 60 seconds, a top coating composition (B) consisting of a hydroxyl group-containing organic resin, an amino resin and an acid catalyst is coated on the undercoat coating film at a dry film thickness of 10 to 50 μm.
Material reaching maximum temperature (PMT) 170-260 ℃ 15-
Matte coated metal plate obtained by heating and curing for 90 seconds.