CN1398934A - Paint composition for metal product - Google Patents

Abstract

A coating composition for metal products, characterized in that 40-90 parts (weight) of resin for baking varnish, 5-50 parts (weight) of amino resin, and 3-10 parts (weight) of epoxy resin . The coating composition for metal products has excellent adhesion to non-ferrous metals such as aluminum, zinc, lead, and various metals such as stainless steel, and has flexibility, impact resistance, weather resistance, water resistance, moisture resistance, and abrasion resistance. Excellent physical properties such as scratch resistance, and can form a coating film with excellent pattern design properties such as gloss and appearance.

Description

Coating composition for metal articles

technical field

The present invention relates to a coating composition for metal products, and its object is to provide a coating composition that has excellent adhesion to non-ferrous metals such as aluminum, zinc, lead, and various metals such as stainless steel, and has flexibility, impact resistance, and weather resistance. , water resistance, moisture resistance, and scratch resistance and other excellent physical properties, and can form a coating film with excellent pattern design properties such as gloss and appearance. A coating composition for metal products.

Background technique

When decorating the exterior of automobile parts such as cars, motorcycles, buses, and trucks, home appliances, industrial machinery, or metal products such as buildings, coating is performed to form a coating film for the purpose of protecting and beautifying the metal product. The coating film is required to have various physical properties such as high weather resistance, transparency, and adhesion, and in recent years, the coating film has been required to have more excellent various physical properties.

In coatings for coating the surface of metal products, polyester resins are usually used as coatings with excellent adhesion, excellent impact resistance and scratch resistance, as well as coatings that use only solvent degreasing. Resin, the coating that uses amino resin as a crosslinking agent, that is, amino ester resin coating.

In addition, depending on the application of the metal product, a coating film particularly excellent in specific physical properties is required. For example, coating films formed on the surfaces of clubs, tennis rackets, golf club heads, etc. as sporting goods are required to have particularly high impact resistance and abrasion resistance in addition to excellent design such as appearance. hurtful.

In order to obtain a coating that can form these physical properties, especially a coating film with excellent impact resistance and scratch resistance, it is possible to mix the amino resin as a crosslinking agent, that is, benzoguanamine resin (ie: melamine Diamine resin) to achieve. By blending benzoguanamine resin, it is possible to form a coating film excellent in adhesion, gloss, flexibility, impact resistance, and scratch resistance.

However, although the coating film formed by the paint containing benzoguanamine resin is excellent in adhesion, gloss, softness, impact resistance and scratch resistance, it has disadvantages in weather resistance, Problems with poor water resistance and moisture resistance. Therefore, it is difficult to use a paint containing a benzoguanamine resin particularly as a paint for metal products used outdoors.

Contents of the invention

In view of this situation, the object of the present invention is to provide a kind of coating composition for metal products, it is the coating composition for metal products containing resin for baking varnish, amino resin, epoxy resin with certain specific ratio, to each It has excellent adhesion to this kind of metal, and has excellent physical properties such as flexibility, impact resistance, weather resistance, water resistance, moisture resistance, and scratch resistance, and can form gloss and appearance. Excellent pattern design coating film to overcome the defects in the prior art.

The above object of the present invention is achieved in this way: a coating composition for metal products, characterized in that it is combined with 40-90 parts (weight) of resin for baking varnishes, 5-50 parts (weight) of amino resins, 3-10 parts (weight) of epoxy resin.

The coating composition for metal products according to the present invention is characterized in that, on the basis of the total of 100 parts (weight) of the above-mentioned resin for lacquer, amino resin and epoxy resin, one of the following three components can also be added above:

(1) less than 3 parts (weight) of silane coupling agent;

(2) less than 3 parts (weight) of ultraviolet absorbers;

(3) Less than 180 parts by weight of pigment.

The coating composition for metal products of the present invention is characterized in that the resin for baking varnish is preferably one or more of polyester resin, alkyd resin, acrylic resin and epoxy polyester resin.

The coating composition for metal products according to the present invention is characterized in that the above-mentioned amino resin is preferably melamine resin and/or guanamine resin.

The coating composition for metal products of the present invention is characterized in that the above-mentioned amino resin is preferably a mixture of melamine resin and guanamine resin, and the mixing ratio of guanamine resin and melamine resin can be 1:1～3 (weight ratio).

The coating composition for metal products according to the present invention is characterized in that the above-mentioned melamine resin is butyl-etherified melamine resin and/or methyl-etherified melamine resin.

The coating composition for metal products of the present invention is characterized in that the above-mentioned guanamine resin is butylated benzoguanamine resin and/or guanamine resin having a spiro acetal ring.

Detailed ways

The coating composition for metal products involved in the present invention will be described in detail below in conjunction with specific examples. The coating composition for metal products according to the present invention is mainly used as a surface coating for forming the outermost coating film of a metal product to be coated. However, at least (A) resin for baking varnish, (B) amino resin, and (C) epoxy resin are blended as essential components.

The first essential component of the coating composition for metal products according to the present invention is: (A) resin for baking. The resin for baking varnish to be used is not particularly limited, and examples thereof include thermosetting resins such as polyester resins, alkyd resins, epoxy polyester resins, and acrylic resins.

In particular, the present invention preferably uses a polyester resin as the (A) resin for baking varnishes. As the polyester resin used in the present invention, can enumerate: (A1) oil-free polyester resin, (A2) alkyd resin, or the modified product of these resins, for example: (A3) epoxy-modified polyester resin , (A4) acrylic modified polyester resin, (A5) urethane modified polyester resin, (A6) urethane modified alkyd resin, etc.

(A1) An oil-free polyester resin is an esterified product of a polyhydroxy acid component and a polyhydric alcohol component. As the polyhydroxy acid component, phthalic anhydride, isophthalic anhydride, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, etc. Among them, one or more dihydroxy acids or lower alkyl esters of these acids are selected for use. In addition, if necessary, monohydroxy acids such as benzoic acid, crotonic acid, p-tert-butylbenzoic acid, trimellitic anhydride, methylcyclohexyl trihydroxy acid, spiroellitic anhydride and other trivalent or higher polyhydroxy acids can also be used together. Acid etc. In particular, isophthalic acid, terephthalic acid, and lower alkyl esters of these acids are preferably used as the polyhydroxy component in the present invention. These polyhydroxy acid components may be used alone or in combination of two or more.

As the polyhydric alcohol component, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl alcohol, 3-methylpentanediol, 1,4-hexanediol, 1, Dihydric alcohols such as 6-hexanediol. In addition, trihydric or higher polyhydric alcohols such as glycerol, trimethylolpropane, and pentaerythritol may also be used in combination as needed. These polyhydric alcohols may be used alone or in combination of two or more.

The method of producing an esterified product from the above polyhydroxy acid component and the above polyol component is not particularly limited, and any known esterification reaction or transesterification reaction may be used.

Examples of commercially available (A1) oil-free polyester resins include DIC Corporation's product name "Beckoline 46-118"; Mitsui Chemicals' product name "Almatex P645"; Changxing Chemical Corporation's product name Products such as "ETERKYD-5062-X-70-1".

(A2) The alkyd resin is an alkyd resin modified by reacting a fatty acid by a known method in addition to the acid component and alcohol component of the (A1) oil-free polyester resin. Examples of fatty acids include palm oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, saffron oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and tung oil fatty acid. The modification amount (oil amount) of the alkyd resin is not particularly limited, and generally can be below 30%, preferably 5-20%.

Examples of commercially available (A2) alkyd resins include "ETERKYD3803-X-65" manufactured by Eternal Chemical Co., Ltd., "BETERKYD3801-60" manufactured by DIC Corporation, Hitachi Chemical Co., Ltd. Products manufactured by the company under the trade name "Futal Kiddo 804-701A".

Examples of the (A3) epoxy-modified polyester resin include reaction products obtained by reactions such as addition, condensation, and grafting of a polyester resin and an epoxy resin. Specifically, the reaction product of the carboxyl group in the polyester resin and the epoxy group-containing resin prepared from the various components used in the production of the above polyester resin, and the reaction product of the hydroxyl group in the polyester resin and the epoxy resin in the epoxy resin The hydroxyl groups are combined into reaction products by polyisocyanate compounds.

(A3) The degree of modification in the epoxy-modified polyester resin, generally, the amount of the epoxy resin is 0.1 to 0.3% by weight relative to the epoxy-modified polyester resin.

Examples of commercially available (A3) epoxy-modified polyester resins include: DIC Corporation's product name "ベッコゾゾル P-790-50" and Mitsui Chemicals' product name "ェポキゾ-701HV" ", products such as "ETERKYDNP1022-R-50" manufactured by Eternal Chemical Co., Ltd.

Examples of (A4) acrylic-modified polyester resins include carboxyl groups or hydroxyl groups in polyester resins made from various components used in the production of the above-mentioned polyester resins, and groups containing reactive groups. Groups, such as carboxyl, hydroxyl or epoxy reaction products of acrylic resins; and polyester resins and (meth)acrylic acid and (meth)acrylates, etc., using peroxide polymerization initiators, prepared by graft polymerization formed reaction product.

The degree of modification in the (A4) acrylic-modified polyester resin, generally, the amount of the acrylic resin is 0.1 to 50% by weight in the acrylic-modified polyester resin.

Commercially available (A4) acrylic-modified polyester resins include "M-1400" manufactured by Showa Sunis Co., Ltd. and "Acrylic M-1156" manufactured by DIC Corporation.

Examples of (A5) urethane-modified polyester resins include the above-mentioned oil-free polyester resins, or low-molecular-weight oil-free polyesters obtained by reacting the acid components or alcohol components used in the production of the above-mentioned oil-free polyester resins. Resins, products of reaction with polyisocyanate compounds by known methods.

In addition, examples of (A6) urethane-modified alkyd resins include the above-mentioned alkyd resins, or low-molecular-weight alkyd resins obtained by reacting various components used in the production of the above-mentioned alkyd resins. Method, product of reaction with polyisocyanate compound.

The reason for introducing a urethane bond, as in (A5) urethane-modified polyester resin and (A6) urethane-modified alkyd resin, is that processability and impact resistance can be improved by introducing a urethane bond.

Examples of polyisocyanate compounds used in the production of (A5) urethane-modified polyester resins and (A6) urethane-modified alkyd resins include hexamethylene diisocyanate, isophorone diisocyanate, Xylylene diisocyanate, tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 4,4-methylene bis(cyclohexyl isocyanate), 2,4,6-triisocyanatotoluene wait.

(A5) urethane-modified polyester resin and (A6) urethane-modified alkyd resin, generally speaking, the amount of polyisocyanate compound is preferably at the In the fermented acid resin, reach the degree of modification below 30% (weight).

Commercially available (A6) urethane-modified alkyd resins include those manufactured by Showa Shines Co., Ltd. under the trade name "Shozukid UAL-031-45D".

Among the various polyester resins specified above, the polyester resin preferably used is (A1) oil-free polyester resin. In particular, the acid value is preferably 2-14 mgKOH/g, preferably 4-10 mgKOH/g, and the average molecular weight is preferably 1500-30000, preferably 5000-20000 oil-free polyester resin. Examples of such commercially available oil-free polyester resins include: DIC Corporation's product name "Beckoline 46-118", Mitsui Chemicals Corporation's product name "Almatex P645", Changxing Chemical Corporation's product name Products such as "ETERKYD-5062-X-70-1".

In the present invention, one kind of the above-mentioned (A) resin for baking varnish may be blended alone, or two or more kinds thereof may be blended.

The compounding quantity of (A) resin for baking varnishes is not specifically limited, It can be 40-90 parts by weight, Preferably it is 50-80 parts by weight, Most preferably, it is 60-75 parts by weight. The reason is that when the amount is less than 40 parts (weight), the flexibility of the coating film tends to decrease, and when the amount is greater than 90 parts (weight), the crosslinking density of the coating film decreases, and various physical properties decrease. , so anything outside the range of 40 to 90 parts by weight is undesirable.

The second essential component of the coating composition for metal products according to the present invention is: (B) amino resin. Amino resin is compounded as a crosslinking agent. The amino resin used in the present invention is not particularly limited, but examples thereof include amino components such as melamine, urea, benzoguanamine, acetylguanamine, steroguanamine, spiroguanamine, dicyandiamide, and Melamine resin, urea resin, guanamine resin, etc. obtained by aldehyde reaction, preferably use (B1) melamine resin, (B2) guanamine resin.

As a specific example, as (B1) melamine resin, there may be mentioned methylolated amino resins obtained by the reaction of melamine and aldehydes, or methylolated amino resins, which are etherified with appropriate alcohols. The generated alkyl etherified melamine resin and the like.

Formaldehyde, paraformaldehyde, acetaldehyde, etc. are mentioned as an aldehyde used at the time of manufacture of the said methylolation amino resin. In addition, examples of alcohols used in the production of the above-mentioned alkyl etherified melamine resins include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylbutanol, 2 -Ethylhexanol, etc.

In particular, in the present invention, as (B1) melamine resin, it is preferable to use methylated melamine resin and n-butyl etherified melamine resin, especially from the viewpoint of weather resistance, it is more preferable to use methylated melamine resin. of melamine resin.

Examples of commercially available methylated melamine resins include products such as "Symel 303" manufactured by Mitsui Cytech Co., Ltd., and "Superbeckamin L-105-60" manufactured by DIC Corporation. .

In addition, examples of commercially available n-butyl etherified melamine resins include: DIC Corporation's product name "Suppa Beckamin G-821-60", Eternal Chemical's product name "ETERMINO9216-60 "And other products.

Examples of the (B2) guanamine resin include reaction products of amino components such as benzoguanamine, acetylguanamine, steroguanamine, and spiroguanamine and aldehydes. Examples of the aldehyde used in the above reaction include the same formaldehyde, paraformaldehyde, and acetaldehyde as described above.

In addition, (B2) guanamine resins include alkyl etherified guanamine resins that are etherified with appropriate alcohols. As the alcohol used in the above reaction, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylbutanol, 2-ethylhexanol, etc. wait.

In the present invention, as (B2) guanamine resin, adopt the butylated benzoguanamine resin formed by etherifying the guanano resin formed by benzoguanamine and formaldehyde through n-butanol, Alternatively, it is preferable to use a guanamine resin (3,9-bis[2-(3,5-dicyano-2,4,6-tris Azaphenyl) ethyl] 2,4,8,10-tetraspiro [5,5] n-undecane) and the alkyl etherification reactant of formaldehyde and n-butanol, promptly have by following formula 2 ( 2) A guanamine resin having a spiro acetal ring represented by the following formula 2 (Formula 2) is more preferably used. The reason is that the physical properties of the cured coating film when using a guanamine resin having a spiro acetal ring represented by the following formula 2 (Chem. It is more excellent in weather resistance, water resistance, moisture resistance and pollution resistance.

【Chemical 1】

【Chemical 2】

Examples of the butylated benzoguanamine resins sold on the market include “Delamin T-100-S” manufactured by Fuji Chemical Co., Ltd., and “Superbeckamin T-100-S” manufactured by DIC Corporation. TD-126", products such as "ETERMINO9411-75" manufactured by Eternal Chemical Co., Ltd.

In addition, examples of commercially available guanamine resins having a spiroacetal ring include products such as "Delamin CTU-100" manufactured by Fuji Chemical Corporation.

In addition, in the present invention, two or more types of (B) amino resins may be mixed in any ratio and used. Especially in this invention, it is preferable to mix and use (B1) melamine resin and (B2) guanamine resin. When (B1) melamine resin and (B2) guanamine resin are mixed and used, the mixing ratio is not particularly limited, but it can be B2: B1 = 1: 1 to 3 (weight ratio), preferably 1:1-2.5, more preferably 1:1.1-2.0. The reason is that when the blending amount of (B1) melamine resin is lower than (B2) the blending amount of guanamine resin, it is considered that the weather resistance of the coating film tends to decrease, and the blending amount of (B1) melamine resin exceeds (B2) ) when the compounding amount of guanamine resin is 3 times, it is considered that the impact resistance of the coating film tends to decrease, so any situation outside the range of B2:B1=1:1~3 (weight ratio) is not acceptable. ideal.

The blending amount of (B) amino resin as the second essential component of the present invention is not particularly limited, and may be 5 to 50 parts by weight, preferably 15 to 40 parts by weight, more preferably 20 to 35 parts ( weight). The reason is that when the compounding amount is less than 5 parts by weight, the curability of the coating film is lowered, and various physical properties are lowered, which is not preferable. On the other hand, when the compounding amount exceeds 50 parts by weight, the flexibility of the coating film is lowered, which is also unfavorable.

The third essential component involved in the present invention is: (C) epoxy resin. The epoxy resin used in the present invention is not particularly limited, but examples include: glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidylamino type epoxy resin and cyclic oxirane type epoxy resin resin etc. In particular, a bisphenol A type epoxy resin synthesized from bisphenol A and epichlorohydrin is preferably used in the present invention. The reason is that since the bisphenol A epoxy resin has both the toughness of the bisphenol A resin and the flexibility of the ether bond, it is excellent in adhesiveness, corrosion resistance and chemical resistance. The epoxy equivalent of the bisphenol A type epoxy resin is not particularly limited, but the preferred range is 300 to 2000 (g/eg). In addition, the amino equivalent weight of the bisphenol A type epoxy resin is not particularly limited, but the preferred range is 400-1000 (g/eg).

Examples of commercially available (C) epoxy resins include "Epicoat 1001×50" manufactured by Yuka Shirepokishi Co., Ltd., and "Epicoat YD-011" manufactured by Togun Chemical Co., Ltd. , products such as "EPICLON 1050-70X" manufactured by DIC Corporation.

(C) Epoxy resins may be compounded alone or in combination of two or more.

The compounding amount of (C) epoxy resin is not particularly limited, however, it may be 1 to 10 parts by weight, preferably 3 to 7 parts by weight, and more preferably 3 to 5 parts by weight, in the total solid content of the paint. parts (weight). The reason is that when the compounding amount is less than 1 part (weight), it is not preferable because the adhesive effect is insufficient. On the other hand, when the compounding amount exceeds 10 parts by weight, since the hardness of the coating film tends to decrease, it is also not preferable.

The above are the essential components of the coating composition for metal products according to the present invention, but in the present invention, one of (D) a silane coupling agent, (E) an ultraviolet absorber, and (F) a coloring pigment can be optionally mixed as needed. more than one species.

In the present invention, the (D) silane coupling agent can be arbitrarily blended as appropriate. By blending a silane coupling agent, it is possible to improve the adhesion effect to all metal materials.

The silane coupling agent used is not particularly limited, and examples include: silicone compounds having reactive functional groups such as alkoxy groups and glycidyl groups, specifically, aminoethylaminopropylmethoxysilane, aminopropyl Aminosilane compounds such as trimethoxysilane, aminopropyldimethoxysilane, aminopropyltriethoxysilane, aminopropyldiethoxysilane, etc.

In particular, in the present invention, as (D) the silane coupling agent, a compound represented by the following formula 3 (Chem. 3) having at least two functional groups with different reactivity in one molecule is preferably used. The reason is that the alkoxy groups of the silane coupling agent are hydrolyzed into silanol groups under the action of water or moisture, and the silanol groups form Si-O-M bonds through condensation reaction with the inorganic surface. On the other hand, the reactive group X may be bonded to the organic matter, or may be compatible without bonding. As a result, the inorganic matter and the organic matter are chemically bonded to improve the adhesion.

【Chemical 3】

(In the formula: X is a reactive group chemically combined with organic materials such as vinyl, epoxy, amino, methacryl, mercapto and other synthetic resins; OR group is a group that combines with methoxy, ethoxy, etc. A reactive group for chemical bonding of inorganic materials such as glass and metal.)

As commercially available (D) silane coupling agents, Shin-Etsu Chemical Co., Ltd. product name "KBM-503", a brand name "KBM-403", a product name "KBM-603", etc. are mentioned.

When blending (D) the silane coupling agent, one of the above-mentioned silane coupling agents may be blended alone, or two or more kinds may be blended and blended.

In the case of compounding (D) silane coupling agent, its compounding amount is not particularly limited, but it can be less than 3 parts by weight, preferably 0.1 to 2.5 parts by weight, more preferably 0.3 to 2.0 parts by weight. The reason is that even if the compounding amount exceeds 3 parts (weight), further improvement of adhesiveness is not found, and it is economically disadvantageous, so it is not preferable.

In the present invention, the (E) ultraviolet absorber may be arbitrarily blended as appropriate. By adding UV absorbers, the weather resistance of the coating film can be significantly improved.

The (E) ultraviolet absorber to be used is not particularly limited, and salicylates, benzophenols, benzotriazoles, phenylsalicylates, diphenylacrylates, One or more mixtures of acetylphenols and cyanoacrylate compounds. Moreover, better effects can be obtained by using UV stabilizers and hindered amine stabilizers (HALS) together.

In the case of compounding ultraviolet absorbers, there is no special restriction on the compounding amount, but on the basis of 100 parts (weight) of the total compounding amount of the essential components (A, B, C), the compounding amount can be less than 3 parts (weight) ), preferably 0.5 to 3 parts by weight, more preferably 1.0 to 2.5 parts by weight. The reason is that even if the compounding amount exceeds 3 parts by weight, further improvement of the weather resistance effect is not found, and it is uneconomical, so it is not preferable.

Furthermore, in the present invention, the (F) coloring pigment may be optionally blended as appropriate. Usable coloring pigments include: coloring pigments commonly used in the paint field, for example, white pigments such as titanium white and zinc white, blue pigments such as cyanine blue and indanthrene, and green pigments such as cyanine green and green cyan. Pigments, organic red pigments such as azo and quinacridines, red pigments such as iron red, benzimidazoles, isoindolinones, organic yellow pigments such as isoindolins and quinphthalones, titanium Yellow pigments such as yellow and yellow lead, black pigments such as carbon black, black lead, and pine smoke, bright pigments such as aluminum powder, copper powder, nickel powder, titanium oxide-coated mica powder, iron oxide-coated mica powder, and bright graphite wait. (F) The compounding quantity of a coloring pigment should just be in the range which can form a topcoat film and does not affect the transparency of a topcoat.

Furthermore, in the present invention, a humidifying raw material, an antifoaming agent, a coating film regulator, a curing catalyst, an inorganic fine powder, etc. can be arbitrarily blended as appropriate within the range that does not impair the effect of the present invention.

The coating composition according to the present invention contains (A) organic resin for baking varnish, (B) amino resin, and (C) epoxy resin as essential components, and (G) solvent may be blended as necessary. The solvent is added to improve the finishing performance of the coating composition of the present invention. The solvent usable in the present invention is not particularly limited as long as it can dissolve or disperse the above-mentioned solid content. Specifically, hydrocarbon solvents such as toluene, xylene, and high-boiling petroleum hydrocarbons; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; Ester solvents such as glycol monoethyl ether acetate and diethylene glycol monoethyl ether acetate; methanol, ethanol, butanol and other alcohol solvents; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl Ether alcohol solvents such as ether; or water, etc. These solvents may be used alone or in combination of two or more.

The compounding amount of (G) solvent is not particularly limited, but on the basis of 100 parts (weight) of the total paint solid content, the compounding amount can be 15 to 60 parts (weight), preferably 20 to 55 parts ( weight), more preferably 25 to 50 parts (weight). The reason is that when the compounding amount is less than 15 parts by weight or more than 60 parts by weight, it is difficult to adjust the viscosity of the paint product, which is not preferable.

The method of forming a coating film using the coating composition for metal products according to the present invention is not particularly limited, and the coating film may be formed by a 3-layer 3-baking method, a 2-layer 2-baking method or a 2-layer 1-baking method.

Next, an example of a method of coating a metal surface with a paint comprising the above-mentioned paint composition for metal products of the present invention will be described.

Examples of metal products coated with the coating composition for metal products according to the present invention include: aluminum, steel, aluminum with various chemical conversion treatments (such as chromium treatment, etc.), cold-rolled steel sheets, hot-dip galvanized steel sheets, electrogalvanized steel sheets, Metal products such as alloy-plated steel plates, aluminum plates, stainless steel plates, copper plates, copper-plated steel plates, and tin-plated steel plates, or metal products that have been surface-treated with phosphates and chromates on these metal plates, and coated with polyester, etc. Pressed steel plate, copper, brass and stainless steel etc.

First, a cured primer film is formed on the surface of the above-mentioned metal product. The cured film of the primer is formed to improve the corrosion resistance of metal products and the adhesion of the coating film. The method of forming the cured primer film is not particularly limited. For example, it can be prepared by baking and drying the dried coating film to a thickness of 15-20 μm on metal products by manual brushing and other methods. The primer used is not particularly limited, and examples thereof include epoxy-based, polyester-based, acrylic-based, and modified primers thereof.

Also, as described above, the primer may be applied to the metal surface to form a primer cured film, or the primer may not be formed on the metal surface.

Next, on the metal product with or without the cured film of the primer, the surface base paint is painted and then baked. Surface base coating is a coating that forms a surface base coating film between the surface coating film and the cured film of the primer or the surface of the metal product. The surface layer base paint used is not particularly limited, and paints containing (a) an organic resin for baking varnishes, (b) an amino resin, and (c) an epoxy resin can be preferably used.

The (a) resin for baking varnish mixed in the surface layer base paint is not particularly limited, for example, one or more than two kinds of polyester resin, alkyd resin, acrylic resin and epoxy polyester resin can be mentioned. mixture.

Among the various resins mentioned above, polyester resins among them can be used. Examples of the polyester resin include the polyester resins described in A and A1 to A6 above. Among them, it is preferable to use an oil-free polyester resin. The average molecular weight of the oil-free polyester resin is not particularly limited, but is preferably 5,000 to 2,000. Also, the acid value is not particularly limited, but is preferably 4 to 10 mgKOH/g.

The compounding quantity of (a) resin for baking varnishes is not specifically limited, It can be 40-90 parts by weight, Preferably it is 60-75 parts by weight.

Examples of the (b) amino resin to be blended in the surface layer base paint include the amino resins described in B and B1 to B2 above. Particularly in the present invention, it is preferable to use a melamine resin and a guanamine resin as the (b) amino resin, and it is more preferable to use a mixture of a melamine resin and a guanamine resin.

The compounding quantity of (b) amino resin is not specifically limited, It can be 5-50 parts by weight, Preferably it is 20-35 parts by weight.

Examples of the (C) epoxy resin to be blended in the surface layer base paint include the epoxy resins described in C above. In particular, in the present invention, it is preferable to use a bisphenol A type as the epoxy resin, and it is more preferable to use an epoxy resin having an epoxy equivalent of 450 to 500 (g/eg).

The compounding quantity of (C) epoxy resin is not specifically limited, It can be 1-10 parts by weight, Preferably it is 3-5 parts by weight.

Furthermore, the (d) coloring pigment may be optionally blended in the surface layer base paint as appropriate. As the coloring pigment used, can enumerate: the coloring pigment that generally uses in coating field, for example, white pigments such as titanium white, zinc white, blue pigments such as cyanine blue, indanthrene, green pigments such as cyanine green, green blue. , organic red pigments such as azo and quinacridines, red pigments such as iron red, organic yellow pigments such as benzimidazoles, isoindolinones, isoindolinones and quinphthalones, titanium yellow , yellow lead and other yellow pigments, carbon black, black lead, pine smoke and other black pigments, aluminum powder, copper powder, nickel powder, titanium oxide coated mica powder, iron oxide coated mica powder and bright graphite and other bright pigments, etc. .

There is no special limitation on the compounding amount of (d) coloring pigment, as long as it can be within the range of good beautiful decoration effect. Generally, when the total compounding amount of (a), (b) and (c) is 100 The compounding amount can be used within the range of 1 to 180 parts (weight) on the basis of parts (weight).

In addition to (a) organic resin for baking varnish, (b) amino resin, (c) epoxy resin, and (d) coloring pigment, (e) solvent may be added to the surface base paint.

The solvent to be mixed in the top coat base paint is mixed as needed to improve the finishing performance, and solvents capable of dissolving or dispersing the above (a), (b) and (c) can be used. Specifically, hydrocarbon solvents such as toluene, xylene, and high-boiling petroleum hydrocarbons; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; ethyl acetate, butyl acetate, etc. , ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate and other ester solvents; methanol, ethanol, butanol and other alcohol solvents; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Ether alcohol solvents such as monobutyl ether; or water, etc.

The compounding quantity of (e) solvent is not specifically limited, It can be 20-55 parts (weight) based on 100 parts (weight) of the total solid content compounded with respect to the surface base paint, Preferably it is 25-50 parts (weight).

The surface base paint is essentially composed of organic resins for baking varnishes, amino resins, epoxy resins, and coloring pigments and solvents that are mixed as needed, and preferably, talc, clay, Moisture-resistant pigments such as mica, silica, and alumina; rust-proof pigments such as strontium chromate, potassium chromate, zinc chromate, barium chromate, and zinc phosphate; additives such as curing catalysts, defoamers, and coating regulators.

The finishing method of the surface base paint is not particularly limited, and examples thereof include spray coating, gate-type automatic casting, knife coating, roll coating, pour coating, and dip coating.

In addition, the firing temperature of the surface base paint is not particularly limited, and may be 130 to 150°C. The firing time is also not particularly limited, and may be 10 to 20 minutes.

After the surface base coating is fired to form a surface base coating film, a top coating composed of the coating composition for metal products according to the present invention is applied and fired. The coating method of the top coat is not particularly limited, and examples thereof include spray coating, sluice casting, knife coating, roll coating, pour coating, and dip coating.

In addition, the thickness of the applied topcoat is not particularly limited, and the thickness of the coating film after drying may be 5-20 μm, preferably 5-10 μm. Furthermore, the coating film can be formed by heat treatment at 130 to 160°C, preferably at a firing temperature of 150 to 160°C, for 20 to 40 minutes, preferably 30 to 40 minutes.

The metal products manufactured in this way, the outermost layer is coated with a surface coating compounded with a baking resin, an amino resin, and an epoxy resin to form a coating film, so it has adhesion, gloss, flexibility, and anti-corrosion properties. Impact, weather, water and humidity resistant metal products.

Example

The present invention will be described below based on examples, but the present invention is not limited by these examples. In addition, the compounding quantity is a weight part.

1. Sample preparation

According to the composition in Table 1, various samples of Examples 1-9 and Comparative Examples 1 and 2 were formulated.

Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Comparative example 1 Comparative example 2 thermosetting resin Oil-free polyester resin (*1) 66 64 63 66 63 70 70 70 70 - - Oil-modified short oil alkyd resin (*2) - - - - - - - - - 77 - Acrylic resin for baking varnish (*3) - - - - - - - - - - 77 Mixture of bisphenol A type solid epoxy resin and xylene (*4) 5 5 5 5 5 5 5 5 5 - - crosslinking agent Low molecular weight methyl ether melamine resin (*5) - - - twenty one twenty one - 13 13 - - N-Butylated Melamine Resin(*6) twenty one twenty one twenty one - - 13 13 twenty three twenty three Butylated Benzoguanamine Resin(*7) 8 9 11 8 11 6 6 - - - - Formaldehyde-Butanol Modified Guanoamine Resin (*8) - - - - - 6 6 12 12 - -

(*1) Product name: "Eterkyd 5062-X-70-1", produced by Eternal Chemical Industry Co., Ltd.

(*2) Product name: "ベッコゾ一ル ER-3653-60", manufactured by Dainippon Inki Chemical Industry Co., Ltd.

(*3) Product name: "Akritec 54-172-60", manufactured by Dainippon Inki Chemical Industry Co., Ltd.

(*4) Product name: "ェピコート1001×50", produced by Yuka Shirepokishi Co., Ltd.

(*5) Product name: "Saimel 303", manufactured by Mitsui Cytech Co., Ltd.

(*6) Product name: "Yuban 20SE60", manufactured by Mitsui Cytech Co., Ltd.

(*7) Product name: "Etermino 9411-75", manufactured by Eternal Chemical Industry Co., Ltd.

(*8) Product name: "Delamin CTU-100", manufactured by Fuji Chemical Industry Co., Ltd.

In addition, the compounding quantity of the thermosetting resin and a crosslinking agent in Table 1 is shown by solid content weight. The special diluent (methyl ethyl ketone: butyl acetate: methoxybutyl acetate: isobutanol: butyl carbinol: xylene: solben-100 (Solbesso-100) = 5: 10: 15: 10 : 10: 30: 20 (weight ratio)) is used to adjust the viscosity of the coating, and adjust the viscosity of the surface coating to 13-15 seconds (Ford cup 4#, 20 ° C).

Fabrication of test panels

On the hot-dip galvanized steel sheet with a thickness of 0.8 mm after chromate treatment, first, use a special thinner to adjust the viscosity of the surface base paint recorded in Table 2 and Table 3 below to 18 to 20 seconds (Ford cup 4#, 20°C), coating is carried out so that the dry film thickness reaches about 20 μm. Then, bake for 20 minutes to make the raw material blank reach the maximum temperature of 150°C (however, Comparative Example 1 is 120°C for 20 minutes), and then use the samples of Examples 1 to 9 and Comparative Examples 1 and 2 made above as The surface coating, the combinations shown in Table 2 and Table 3 below, is applied by spraying method, so that the dry film thickness reaches about 10 μm. Next, firing was performed for 30 minutes to bring the raw material billets to a maximum temperature of 150° C. (however, in Comparative Example 1, it was 120° C. for 20 minutes) to obtain various sample steel sheets.

In Table 2 and Table 3, "DB-1" uses a white surface layer of polyester-melamine resin manufactured by Dafeng Paint Co., Ltd. with the trade name "Supercoat DB-5201 White". coating. "DB-2" used an alkyd-melamine resin-based white surface paint with a trade name of "Daimin White" manufactured by Dafeng Paint Co., Ltd. And "DB-3" uses a white surface coating of acrylic-melamine resin manufactured by Taifeng Paint Co., Ltd. under the trade name "Akrin White".

Test Example 1: Appearance of the coated surface

The coating film appearance of the test coated panels coated with various samples of Examples 1 to 9 and Comparative Examples 1 and 2 was evaluated visually according to the following evaluation criteria. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

⊚: There is no abnormality in the coating film, and it is good.

x: Abnormalities in the coating film were confirmed.

Test Example 2: Pencil Hardness

Using the pencil scratch test stipulated in JIS K-5600-5-4 11.4.20 (1999), the hardness of the coating film on the test coated panels coated with various samples of Examples 1 to 9 and Comparative Examples 1 and 2 , to evaluate. The results are recorded in Table 2 and Table 3.

Test Example 3: Adhesion

According to the base mesh belt method test specified in JIS K-5400-5-6 11.4.20 (1999). First, on the surface of the coating film of the test coating plate coated with various samples of Examples 1 to 9 and Comparative Examples 1 and 2, use a scissors to draw 11 vertical and horizontal lines parallel to each other at intervals of 1 mm. Draw a straight line to the substrate and make 100 square meshes of 1mm×1m. Adhere the surface with an adhesive film adhesive tape, observe the degree of peeling of the entire mesh when the tape is quickly peeled off, and evaluate according to the following evaluation criteria. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

◎: The cut edge was completely smooth, and any grid mesh was not peeled off.

◯: At the intersection of cuts, the coating film has small peeling. In the cross-cut section, the affected clear did not reach 5%.

Δ: The coating film was lifted at the cut edge, and/or peeled off at the intersection. In the cross-cut segment, the affected clearly exceeded 5%, but did not rise to 15%.

×: The coating film lifts up at the edge of the cut, and partial or complete large peeling occurs, and/or partial or complete peeling occurs in each part of the mesh. In the cross-cut segment, the affected clearly exceeded 15% but did not rise to 35%.

Test Example 4: Impact Resistance

DuPont-type impact resistance test is carried out in accordance with JIS K 5400. First, a core driver (head diameter = 1/2 inch) was placed on a test coating plate coated with various samples of Examples 1 to 9 and Comparative Examples 1 and 2. A weighted slider (500 g) was dropped onto the core from a height of 50 cm, and the peeling state of the coating film was evaluated according to the following evaluation criteria.

Evaluation benchmark

◎: Peeling did not occur.

△There is peeling.

Test Example 5: Drawing Test

Using the rotation of the loaded needle and the lateral movement of the sample stage, a cycloid-like curve is drawn on the surface of the coating film, and the coating film is analyzed by the traces and peeling states generated on the sample surface (more than 20). Hardness, adhesion, etc. were compared and evaluated. In this test, evaluation was performed with a copper load of 500g×10m/m (arc). The results are recorded in Table 2 and Table 3.

Test Example 6: Cupping Test

The cupping test was performed in accordance with JIS K-5400. First, extrude the steel ball with a punch with a spherical head (20 mmφ) until it is extruded from the inside of the test coating plate coated with the samples of Examples 1 to 9 and Comparative Examples 1 and 2, so that the coating film Cracks and peeling occurred, and the extrusion distance at that time was determined (crack distance method). The results are recorded in Table 2 and Table 3.

Test Example 7: Solvent Resistance

In a room at 20°C, the gauze soaked with methyl ethyl ketone was placed on the coated surface of the test plate coated with each sample of Examples 1 to 9 and Comparative Examples 1 and 2, and a load of about 1 kg/ ^cm2 was applied. Under certain conditions, make it go back and forth between a length of about 5cm, and record the number of back and forth before seeing the substrate. Also, the test coated panel in which the substrate was not seen after 50 round trips was recorded as ">50". The results are recorded in Table 2 and Table 3.

Test Example 8: Acid Resistance Test

The test coated panels coated with various samples of Examples 1-9 and Comparative Examples 1 and 2 were immersed in 5% H ₂ SO ₄ solution at 30° C. for 24 hours, and then left at room temperature for 24 hours. The surface state of the coating film of each sample was evaluated visually according to the following evaluation criteria. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

⊚: No change was observed on the surface of the coating film.

◯: A slight change was observed on the surface of the coating film.

Test Example 9: Alkali Resistance Test

The test coated panels coated with the samples of Examples 1 to 9 and Comparative Examples 1 and 2 were immersed in 5% NaOH solution at 30° C. for 24 hours, and then left at room temperature for 24 hours. The surface state of the coating film of each sample was evaluated visually in accordance with the following evaluation criteria. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

⊚: No change was found on the surface of the coating film.

○: A slight change is found on the surface of the coating film.

Test Example 10: Corrosion Resistance Test

Conduct neutral salt spray resistance test according to JIS K-5400-7-1 11.4.20 (1999). First, the test coated panels coated with the samples of Examples 1 to 9 and Comparative Examples 1 and 2 were kept in the salt water spray test device for 150 hours, and the rust caused by salt water and the occurrence of coating film were evaluated according to the following evaluation criteria The state of swelling and peeling. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

◎: No rust and no change in the coating film.

◯: No rust, but slight change in the coating film.

Test Example 11: Pollution Resistance Test

Contamination resistance test according to JIS K-5400. First, attach contamination materials (marker pen (red) and lipstick specified in JIS S-6037) to the coating surface, and leave it at room temperature for 24 hours. Then, wipe the contaminated material with gauze, and then gently wipe it with a clean gauze washed with ethanol and dried, and evaluate the contamination degree of the sample visually according to the following evaluation criteria. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

⊚: Changes in color and gloss and swelling were not observed.

◯: Color and luster slightly changed, but swelling was not observed.

△: The color and luster changed greatly, but swelling was not observed.

Test Example 12: Weather Resistance Test

Using an accelerated weather resistance tester (trade name: "Sanciainzezaometa", manufactured by Atlas Corporation), the test coating panels coated with each sample of Examples 1 to 9 and Comparative Examples 1 and 2 were tested. In the 500-hour weather resistance test, the change of the coating film before and after the weather resistance test was evaluated visually. The results are recorded in Table 2 and Table 3.

Evaluation benchmark

◎: No special change was found

○: slightly changed

△: Significant change

Table 2 Surface coating Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 surface base paint DB-1 DB-1 DB-1 DB-1 DB-1 DB-1 Coated Appearance ◎ ◎ ◎ ◎ ◎ ◎ pencil hardness 2H 2H 2H 3H 3H 3H tightness ◎ ◎ ◎ ◎ ◎ ◎ Impact resistance ◎ ◎ ◎ ◎ ◎ ◎ drawing test 10/10 10/10 10/10 10/10 10/10 10/10 cupping test 7.0 7.0 7.5 7.0 7.0 7.0 Solvent resistance >50 >50 >50 >50 >50 >50 acid resistance ◎ ◎ ◎ ◎ ◎ ◎ Alkali resistance ○ ○ ○ ◎ ○ ◎ Corrosion resistance uncut ◎ ◎ ◎ ◎ ◎ ◎ cross cutting ○ ○ ○ ◎ ○ ◎ Pollution resistance marker pen (red) ○ ○ ○ ◎ ○ ◎ lipstick ○ ○ ○ ◎ ○ ◎ weather resistance ◎ ◎ ◎ ◎ ◎ ◎

table 3 Surface coating Example 7 Example 8 Example 9 Comparative example 1 Comparative example 2 surface base paint DB-1 DB-1 DB-1 DB-2 DB-3 Coated Appearance ◎ ◎ ◎ ◎ ◎ pencil hardness 3H 3H 2H 2H 2H tightness ◎ ◎ ◎ ◎ ◎ Impact resistance ◎ ◎ ◎ △ △ drawing test 10/10 10/10 10/10 10/10 10/10 cupping test 7.0 7.5 7.5 6.0 6.5 Solvent resistance >50 >50 >50 >50 >50 acid resistance ◎ ◎ ◎ ○ ◎ Alkali resistance ◎ ◎ ◎ ○ ○ Corrosion resistance uncut ◎ ◎ ◎ ○ ○ cross cutting ◎ ◎ ◎ ○ ○ Pollution resistance marker pen (red) ◎ ◎ ◎ △ ◎ lipstick ◎ ◎ ◎ ○ ◎ weather resistance ◎ ◎ ◎ ○ ◎

As mentioned above, the coating composition for metal products related to the present invention is blended with 40-90 parts (weight) of baking varnish resin, 5-50 parts (weight) of amino resin, 3-10 parts ( Weight) epoxy resin has excellent adhesion to non-ferrous metals such as aluminum, zinc, lead, and various metals such as stainless steel. At the same time, it has flexibility, impact resistance, weather resistance, water resistance, moisture resistance and It has excellent physical properties such as scratch resistance, and can form a coating film with excellent pattern design properties such as gloss and appearance.

In addition, in addition to the above-mentioned essential components, by blending 3 parts (by weight) or less of a silane coupling agent, the adhesion of the formed coating film can be improved. The weather resistance of the formed coating film can be remarkably improved by compounding the ultraviolet absorber in an amount of 3 parts (by weight) or less. By adding 180 parts (weight) or less of the pigment, excellent design performance can be imparted to the coating film.

Since the resin for baking varnish is one or more of polyester resin, alkyd resin, acrylic resin, and epoxy polyester resin, a coating film excellent in various physical properties can be formed.

Since the above-mentioned amino resin is a melamine resin and/or a guanamine resin, a coating film excellent in various physical properties can be formed.

Since the above-mentioned amino resin is a mixture of melamine resin and guanamine resin, the mixing ratio of guanamine resin and melamine resin is 1:1 to 3 (weight ratio), so the weather resistance and impact resistance of the coating film can be improved. sex.

Since the above-mentioned melamine resin is a butyl etherified melamine resin and/or a methyl etherified melamine resin, the weather resistance of the coating film can be improved.

Since the above-mentioned guanamine resin is a benzoguanamine resin with butylated ether/or a guanamine resin with a spiro acetal ring, the weather resistance, water resistance, moisture resistance and pollution resistance of the coating film can be improved. sex.

Claims (7)

1. A coating composition for metal products, characterized in that it is mixed with 40-90 parts (weight) of resin for baking varnish, 5-50 parts (weight) of amino resin, and 3-10 parts (weight) of epoxy resin resin. 2. The coating composition for metal products according to claim 1, characterized in that, in addition to the total of 100 parts (by weight) of the above-mentioned resin for baking varnish, amino resin and epoxy resin, the following three components More than one of: (1) silane coupling agents below 3 parts (weight); (2) 3 parts (weight) or less of ultraviolet absorbers; (3) 180 parts (weight) or less of pigments. 3. The coating composition for metal products according to claim 1 or 2, wherein the resin for baking varnish is at least one of polyester resin, alkyd resin, acrylic resin and epoxy polyester resin. 4. The coating composition for metal products according to any one of claims 1 to 3, wherein the amino resin is a melamine resin and/or a guanamine resin. 5. The coating composition for metal products according to any one of claims 1 to 3, wherein the above-mentioned amino resin is a mixture of melamine resin and guanamine resin, and the combination of guanamine resin and melamine resin The ratio is 1:1-3 (weight ratio). 6. The coating composition for metal products according to claim 4 or 5, wherein said melamine resin is butyl-etherified melamine resin and/or methyl-etherified melamine resin. 7. The coating composition for metal products according to any one of claims 4 to 6, characterized in that, the above-mentioned guanamine resin is butylated benzoguanamine resin, and/or has spiro acetal Cyclic guanamine resin.