JPS62258775A - Method for painting metal material - Google Patents

Abstract

PURPOSE:To markedly enhance the chipping resistance, corrosion resistance and physical capacity of a film, by preliminarily applying barrier coat having specific physical properties to an intermediate coat surface prior to applying top coat to a metal material. CONSTITUTION:Electrodeposition painting is applied to a metal material coming to the outer panel of a car using cationic and anionic electrodeposition paints and intermediate painting is subsequently applied by org. solution type thermosetting intermediate coat. A composition forming a film of which the static glass transition temp. is 0--75 deg.C and containing water and/or an org. solvent as a solvent or a dispersing medium is applied to the intermediate coat surface as barrier coat. Further, top coat containing an amino-acrylic resin or an amino- alkyd resin as a vehicle main component is applied to the surface of the barrier coat film in order to impart decorative effect and dried under heating to perform finishing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides chipping resistance to metal materials, especially automobile outer panels.
This invention relates to a coating method for forming a film with excellent corrosion resistance and physical performance.

In the automobile industry, emphasis is being placed on the durability of paint films, particularly problems such as deterioration of the appearance of paint films due to impact peeling and accelerated corrosion of metal materials.

In particular, when a car runs on the road, salt particles and pebbles thrown up by the wheels on the outside of the car can pile up or hit the paint surface.
This impact often causes the impact peeling phenomenon in which the paint film partially peels off from the car body, so-called "chipping 1." This phenomenon often exposes the metal surface of the impact area on the outside of the car body, causing rapid damage. Corrosion progresses as rust develops.

Usually, paint film peeling due to chipping occurs mostly on the bottom of the vehicle body and around the suspension, but it is known that it also occurs on the hood and roof, and localized corrosion becomes noticeable after about six months to a year.

In order to prevent this chipping and the progression of corrosion caused by it, various studies have been carried out on chemical conversion treatment of the surface of the external metal base of the car body, as well as on IE electrodeposition paints, intermediate coats, and top coats.

For example, the use of iron phosphate coatings and zinc phosphate coatings with different crystal forms in chemical conversion treatments has been considered, but such chemical conversion treatments can sufficiently improve the adhesion and latency of coatings on impact areas. What we do is Kokuden. In addition, electrodeposition paint,
Various studies have been conducted on the resins and/or pigments contained in intermediate and top coat paints, but so far no one has been found that has sufficient adhesion-improving effects to withstand chipping. ,
In order to improve the above-mentioned problems, the inventors of the present invention have proposed that the finished appearance is at least equivalent to that obtained by a steel plate coating system consisting of a conventional electrodeposition paint, an intermediate coat paint, and a top coat paint.
Moreover, with the aim of providing a coating method for forming a coating film with excellent chipping resistance, physical properties, and anticorrosion properties, the present invention has been completed as a result of extensive research.

That is, according to the present invention, an electrodeposition paint and an intermediate paint are applied to a metal material, and then,
On the intermediate coating surface, the static glass transition temperature of the formed coating film is θ~
A method for coating metal materials is provided, which comprises coating a coating composition at -75°C and then applying a top coat.

In the present invention, the coating composition that forms a coating film having the above-mentioned characteristic values is abbreviated as "barrier coat".The feature of the present invention is the step of sequentially applying electrodeposition paint, intermediate coat paint, and top coat paint to metal materials. In this method, a barrier coat having specific physical properties is applied to the intermediate coated surface in advance after the intermediate coat is applied and before the top coat is applied. As a result, it was found that it was possible to form f- and @ films with extremely excellent chipping resistance, corrosion resistance, physical performance, etc.

In other words, a barrier coat film with a static glass transition temperature adjusted to 0 to -75°C is more flexible than the intermediate coat film aimed at improving the anti-cheating property, and has such physical properties. Even if a strong impact force is applied to the surface of the top coat film formed through the barrier coat film due to a collision with rock salt or pebbles, most or all of the impact energy will be absorbed within the barrier coat film. It has been found that this does not affect the recoating of the underlying wL layer, and that the top coat film is also hardly physically damaged.

In other words, the barrier coat film layer exhibits a ff (Tr) effect against external impact forces, significantly improving chipping resistance, and preventing rusting and corrosion of metal materials due to chipping. This also eliminated the deterioration of the top coat due to collisions with rock salt, pebbles, etc.

The coating method of the present invention will be explained in more detail below.

Metal material: The metal material to be coated by the method of the present invention is not limited in any way as long as it is a conductive object to be coated and has a metal surface that can be coated by electrodeposition. Examples include materials such as iron, copper, aluminum, tin, zinc, alloys containing these metals, and plated or vapor-deposited products of these metals and alloys. Specifically, passenger cars made using these materials, This includes vehicle bodies and parts for trucks, safari cars, motorcycles, electrical products, and building materials. It is preferable that the metal material is previously subjected to a chemical conversion treatment with a phosphate or chromate prior to being coated with the electrodeposition paint.

Electrodeposition paint: The electrodeposition paint for coating the above-mentioned metal material can be either a known cation type or anion type.

Firstly, cationic @visual paints include cathodic deposition type thermosetting electrodeposition paints that are based on resins with basic amine groups and are neutralized with acid and made water-soluble (moisture edification). is painted using the metal material (object to be coated) as a cathode. Examples of resins with basic amino groups include epoxy groups such as bisphenol-type epoxy resins, acrylic resins containing epoxy groups (or glycidyl groups), glycidyl ethers of alkylene glycols, epoxidized polybutadienes, and epoxy heptadides of novolabbutzenol resins. Addition of amine to the epoxy group (oxirane ring) of the resin contained; ■ Unsaturated compounds with basic amino groups (e.g. dimethylaminoethyl methacrylate, N-vinylpyrazole, N-diethylamine ethyl acrylate, etc.) as a monomer Polymerization used: ■ Tertiary amine group-containing glycol (for example, N
-Methyljetanolamine) as a glycol component and a polyisocyanate compound; ■Introduction of an amino group into the resin by generating iminoamine by reaction with an acid anhydride and a diamine; etc.; The amines that can be used in the reaction (2) above include basic amines such as aliphatic, alicyclic, or aromatic-alicyclic primary amines, secondary amines, tertiary amine salts, and quaternary amines. Examples include class ammonium salts, and secondary sulfide salts and tertiary phosphine salts can also be used.

As a neutralizing agent for neutralizing the resin having a basic amine group and making it water-soluble (moisture #2), for example,
Acetic acid, hydroxyl acetic acid, propionic acid, acetic acid, lactic acid,
Organic acids such as glycine; inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid can be used. The blending amount of the neutralizing agent is determined by the base number (
A range of approximately 20 to 200) K in terms of neutralization equivalent to 0.1 to C), 4 is suitable.

In addition, blocked polyisocyanate compounds are generally used as crosslinking agents for cationic electrodeposition paints.
When the coating film is heated (approximately 140° C. or higher), the blocking agent dissociates, the incyanate group is regenerated, and crosslinks with the hydroxyl group in the cationic resin as described above, resulting in curing. moreover,
Cationic electrodeposition paints contain pigments (coloring pigments, extender pigments,
Rust-preventing pigments, etc. The blending amount of the pigment can be less than 150 parts by weight per 100 parts by weight of the resin solid content), a hydrophilic solvent, water, additives, etc. are blended as necessary, and the solid content concentration is about 5 to 40 parts by weight. It is diluted with deionized water or the like so as to give a weight percent, and the pH is adjusted within the range of 5.5 to 8.0. Cationic electrodeposition coating using a cationic electrodeposition paint coated with K in this way is usually carried out under the conditions of a bath temperature of 15 to 35°C and a load voltage of 100 to 400V, with the object being coated as a cathode. can. ii! The coating film thickness is not particularly limited, but
A range of 10 to 40 microns is preferred based on the cured coating. Generally, a temperature range of 100 to 200°C is suitable for baking and curing the coating film.

On the other hand, anionic electrodeposition paints are anodic deposition type electrodeposition paints that are mainly made of a resin having a carboxyl group and are neutralized with a basic compound and made water-soluble (water lI:r soluble). The metal material (object to be coated) is used as an anode for coating.

Resins with carboxyl groups include: ■Maleated resin obtained by adding maleic anhydride to drying oil (linseed oil, dehydrated castor oil, tung oil, etc.); ■Polybutadiene (1, 2 type, 1.4 type);
Maleated polybutadiene made by adding maleic anhydride to the unsaturated fatty acid ester of epoxy resin; Resins obtained by adding polybasic acids (trimellitic anhydride, maleated fatty acids, maleated parts, etc.) to carboxyl group-containing polyester resins (including esters and styrene/allylic alcohol copolymers); ■ Carboxyl group-containing acrylic resins; ■ Polymers or copolymers formed using the reaction product of a polymerizable unsaturated polymer containing a glycidyl group or an aqueous group and an unsaturated fatty acid. Examples include resins to which maleic anhydride or the like is added, and those having a carboxyl group content in the range of about 30 to 200 based on the acid value are generally suitable. Examples of neutralizing agents for neutralizing the carboxyl groups in these carboxyl group-containing resins and making the resins water-soluble (fractional) include alkanolamines such as monoethanolamine, jetanolamine, and dimethylaminoethanol. / Alkylamines such as diethylamine and triethylamine; Inorganic alkalis such as potassium hydroxide and sodium hydroxide, etc. can be used. The amount of these neutralizing agents to be used is approximately 0.1 to 1.0 times (preferably 0.4 to 0.8 times) the theoretical neutralization equivalent to the acid value of the resin.

Further, as a crosslinking agent for the above resin, a low molecular weight melamine resin such as hexakismethoxymethylmelamine, butoxylated methylmelamine, or ethoxylated methylmelamine can be used as required.

Furthermore, the 1-anion type electric IF housing contains pigments (coloring pigments,
Extender pigments, anti-M pigments, etc. The amount of pigment blended is resin solid content 1
00 parts by weight), a hydrophilic solvent, water, additives, etc. are blended as necessary, and the solid content concentration is about 5 to 4o1(i)% with deionized water, etc. ! jl! and maintain the pH within the range of 7 to 9 to remove the anion 1.
1. Can be used for painting. Anion 11 coat coating can be done according to the usual method, for example, bath temperature 15-35
C. and a load voltage of 100 to 350 V, and the object to be coated can be used as an anode. The coating film thickness is not particularly limited, but it is usually preferably in the range of 10 to 40μ based on the cured coating.Anionic electrolyte films are generally heated at 100 to 200°C, preferably 140 to 200°C. It can be cured by heating within a certain range, but if a resin modified with a 1/L drying unsaturated fatty acid is used, it can also be dried at room temperature.

Intermediate coating paint: As the intermediate coating paint applied to the above-mentioned electrodeposited surface, there are known intermediate coating paints that have excellent adhesion, smoothness, sharpness, overpaint resistance, weather resistance, etc. Can be used. Specifically, an organic solution-type thermosetting intermediate coating material whose vehicle main components are a short-oil or ultra-short-oil alkyd resin with an oil length of 30% or less or an oil-free polyester resin and an amino resin can be mentioned. These alkyd resins and polyester resins have a hydroxyl value of 60 to 140 and an acid value of 5 to 2.
0, and preferably uses an unsaturated oil (or unsaturated fatty acid) as the modified oil, and the amine resin is
Suitable are alkyl (preferably those having 1 to 5 carbon atoms) etherified melamine resin, urea resin, benzoguanamine resin, and the like.

The blending ratio of these two resins is based on the solid weight: alkyd resin and (!!) oil-free polyester resin 65 to 85%, especially 70 to 80%, amine resin 35 to 1%.
It is preferably 5%, especially 30-20%. Furthermore, at least a portion of the above amino resin can be replaced with a polyisocyanate compound or a blocked polyisocyanate compound.

Although the form of the intermediate coating is most preferably an organic solution type, it may also be a non-aqueous dispersion type using the above-mentioned vehicle component, a high solid type, an aqueous solution type, an aqueous solution type, or the like. In the present invention, the hardness of the intermediate coating film (pencil hardness)
Generally, it is preferable that the number is in the range of 3B to 2H.Furthermore, extender pigments, coloring pigments, other paint additives, etc. can be added to the intermediate coating paint as necessary.

In the present invention, the method of applying the above-mentioned ``wt coating surface intermediate coating paint is not particularly limited, and examples include spray coating,
Brush coating, dip coating, electrostatic coating, etc. can be used, and the coating thickness is preferably in the range of 10 to 50 μm based on the cured coating, and the hardening temperature of the coating varies depending on the vehicle composition. , 80-170℃ for heat curing
It is particularly preferable to heat at a temperature in the range of 120 to 150°C.

Barrier coat: The barrier coat is a coating composition for coating on the above-mentioned intermediate coated surface, and in the present invention, it is particularly composed of water and ( or)
A composition using an organic solvent as a solvent or dispersion medium is used.

The composition mainly includes a vehicle and a solvent or dispersion medium,
In addition, tackifiers, organic solvents, coloring pigments, extender pigments, anticorrosion pigments, and the like can be added as appropriate.

The vehicle is preferably a thermoplastic resin that has excellent adhesion to the intermediate coating film and the top coating film and has a static glass transfer temperature within the range of the static glass transition temperature. Things can be mentioned.

■ Modified polyolefin-based laparotomy: For example, propylene-ethylene copolymer (molar ratio, 4
0 to 80:60 to 20% is preferable) and 1 to 50 parts by weight, preferably 10 to 20 parts by weight of chlorinated polyolefin (for example, polypropylene with a chlorination rate of about 1 to 60% by weight) (in both cases, the copolymer (per 100 parts by weight of the combined); or the above propylene-ethylene copolymer 10
0 heavy parts per simalic acid or maleic anhydride 0.
Examples include graft polymers obtained by craft polymerizing i≧parts, preferably 0.3 to 20 parts by weight.

The number average molecular weights of these copolymers, chlorinated polyolefins and kraft polymers range from about 5,000 to about 30.
It is preferably in the @ range of 0000. The above-mentioned constituent gas can be dissolved or dispersed in an organic solvent, and examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, and xylene, and aliphatic carbonizations such as hexane, heptane, octane, and decane. Examples include hydrogen, chlorinated hydrocarbons such as trichlorethylene, perchlorethylene, dichloroethylene, dichloroethane, and dichlorobenzene.

In making the modified polyolefin resin aqueous, the propylene-ethylene copolymer can be made aqueous by anionic, cationic or nonionic emulsion polymerization, which is known per se. The chlorinated polyolefin can be water-solubilized or water-enriched by neutralization, for example, in the presence of an emulsifier.

■ Styrene-butadiene copolymer: Styrene content is approximately 1 to 80% by weight, preferably 10% by weight.
An aqueous dispersion of the copolymer is obtained by copolymerizing styrene and butadiene in the presence of a polymerization modifier, catalyst, soap, and water. The polymerization temperature is preferably 100°C or less. The number average molecular weight of the shredded copolymer is about to, ooo to about 1,00
Preferably, it is in the range of 0,000.

In addition, the above copolymer was coated with an ordinary paint organic solvent.
It is also possible to solve or disperse v\.

0 Butadiene resin: This is an organic solvent-based or water-based composition obtained by polymerizing in (2) above without using styrene.

■ Acrylonitrile-butadiene copolymer: The content of acrylonitrile is 1 to 50%, preferably 10 to 50%.
A 40W% copolymer containing acrylonitrile and butadiene, optionally containing a functional hexamer such as acrylic acid or methacrylic acid, and the presence of a polymerization catalyst, molecule 1, regulator, surfactant, etc. Polymerization can be accomplished by emulsion polymerization in water at low temperatures, or by polymerization in a high pJ solvent. The polymerization temperature is 1 (preferably 10°C or lower).

The number average molecular weight of the copolymer is about 10,000 to about 1.0.
A range of 00,000 is suitable.

(Polybutene: 1 KL is mainly composed of isobutylene, if necessary, normal butylene is mixed, and the resulting polybutene is heated to 50 to 70°C in the presence of an emulsifier, and water is added to homogenize it. The polybutene can be obtained by stirring thoroughly or by dissolving or dispersing the polybutene in an organic solvent for paint.The number average molecular weight of the resin is about 1000 to about 5oooooo.
A range of is preferred.

■ Acrylic resin Niacrylic powder ester and (or) methacrylic acid ester are the main components, and in addition, acrylic acid,
An aqueous dispersion is obtained by emulsion polymerization of a vinyl heptamer composition prepared by mixing functional monomers such as methacrylic acid, hydroxyethyl acrylate, and hydroxypropyl methacrylate and/or other polymerizable unsaturated polymers. : Or, after solution polymerization, it can be obtained by dissolving it in an organic solvent for paint or converting it into an aqueous solution or dispersion. Examples of the acrylic esters include ethyl acrylate, propyl acrylate, n
-butyl acrylate, 1so-butyl acrylate,
3-pentyl acrylate, hexyl acrylate, 2
-hebutyl acrylate, octyl acrylate, 2-
Octyl acrylate, nonyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-
Ethyl butyl acrylate is particularly preferred, and examples of the methacrylic acid ester include pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, and stearyl methacrylate. The static glass transition temperatures of homopolymers derived from acid esters and methacrylic esters are all below 0°C, and one type selected from these monomers (2〈 means two or more acrylic esters) and methacrylic acid esters are suitable monomers for forming the acrylic resin.The acrylic resin has a number average molecular weight of about 5,000 to 1,
Preferably, it is in the range of 000.000.

(7) In addition to these, natural rubber latex,
Methyl methacrylate-butadiene copolymer emulsions, polychloroprene emulsions, polyvinylidene chloride emulsions, etc. can also be used as vehicles themselves.

The coating film formed by the barrier coat has a static glass transition temperature (T2) of 0 to -75°C, preferably -30 to
It is important that the temperature is -60℃, particularly preferably in the range of -40 to -55℃.If the Tg is higher than 0℃, the chipping resistance, corrosion resistance, physical performance, etc. of the 4I layer coating will be improved. On the other hand, if the temperature is lower than -75°C, the water resistance, adhesion, etc. of the multilayer coating will deteriorate, which is not preferable.

In the present invention, if these vehicles themselves have a static glass transition temperature within the above range, they can be used as a barrier coating by themselves, but if the vehicle deviates from the above range or even within the range, the static glass transition temperature cannot be used. When it is desired to finely adjust the glass transition temperature, a viscosity imparting agent can be added as necessary.

As the viscosity imparting agent, resins having good compatibility with the vehicle, such as rosin, petroleum resin (coumarone resin),
Ester gum, epoxy-modified polybutadiene, low-molecular-weight aliphatic epoxy resin, low-molecular-weight aliphatic bisphenol type epoxy resin, polyoxytetramethylene glycol, vinyl acetate-modified polyethylene, etc. are listed, and the blending amount of these is based on the vehicle (solid content) above. 100
A range of 1 to 50 parts by weight (as solids) per part by weight is preferred.

Furthermore, extender pigments, coloring pigments, anti-corrosion plantings, etc. may be added to the barrier coat.

The blending amount of these ingredients is preferably in the range of 1 to 150 parts by weight per 100 parts by weight of vehicle (solid content).

In the present invention, regarding the formed coating film of the barrier coat,
Although it is essential that the static glass transition temperature is within the above range, it is also necessary to increase the tensile strength elongation of the coating film itself at a tensile rate of 20 W/20 in an atmosphere of -20°C.
If the amount is adjusted within the range of 200 to 1000%, particularly 300 to 700%, the chipping resistance, corrosion resistance, etc. of the final coating film can be further improved.

(Daini Seiko Kin DSC-10FM), and the "tensile breaking strength elongation rate" is a value measured using a universal tensile tester with a constant temperature bath (Shimadzu Autograph S-D model). is a value measured at 20+w and a tensile speed of 20 cod/min. The samples used for these measurements would have been isolated by the mercury amalgam method after coating the barrier coat on a tin plate for 25 seconds based on the formed coating, baking it at 120°C for 30 minutes. In the present invention, the barrier coat can be applied either after heating and curing the coating film or in an uncured state, and the coating film has a coating film of 1 to 20% based on the coating film formed.
μ, particularly preferably 5 to 10 μ.

When applying the top coat to the barrier coat coating surface, it is preferable to bake the barrier coat in advance, but it is also possible to apply the top coat wet-on-wet without baking. Generally, a baking temperature range of 80 to 200°C is suitable.

Top coat is a paint that is applied to the above-mentioned barrier coated surface, and is used to impart cosmetic properties to the coated object. Specifically, the finished appearance (sharpness, smoothness, gloss, etc.), weather resistance (gloss retention, color retention, chalking resistance, etc.), chemical resistance, water resistance, moisture resistance, hardenability, etc. Paints known per se that form a coating film with excellent properties can be used, such as paints whose vehicle main component is an amino-acrylic resin, an amino-alkyd resin, an amino-polyester resin, or the like. The form of these paints is not particularly limited, and may include organic solution type, non-aqueous dispersion type,
Any form can be used, such as water-soluble wave type, powder type, and high solid type. Drying or curing of the coating film is carried out by drying at room temperature, heating drying, irradiation with active energy rays, etc. In the present invention, it is desirable that the paint film formed by these top coats has a pencil hardness usually in the range of 2B to 3H.

The top coat used in the present invention is a paint whose main component is the above-mentioned vehicle, a metallic pigment and (!!)
The paint may be either an enamel paint containing colored pigments or a clear paint containing no or almost no pigments.

Examples of methods for forming a top coating film using these paints include the following methods: (1) Metallic paints, which are made by blending metallic pigments and, if necessary, coloring pigments; A method of applying a solid color paint containing pigments and curing it by heating (metallic or solid color finish using the 1-coat, 1-bake method).

After applying CI metallic paint or solid color paint and curing by heating, apply clear paint.
Method of heating and curing again (metallic or solid color finish using 2-coat, 2-bake method).

■ A method in which metallic paint or solid color paint is applied, followed by clear paint, and then both coatings are cured at the same time by heating (metallic or solid color finishing using a 2-coat, 1-bake method).

These top coat paints are preferably applied by spray painting, electrostatic painting, or the like. In addition, the coating film thickness is in the range of 25 to 40 J1 in the above (■), based on the dry coating film, and in the above (■).
and ■, metallic paints and solid color paints range from 10 to 30j, and clear paints range from 25 to 50j.
Each of these ranges is preferable. Heating conditions can be arbitrarily adopted depending on the vehicle components, but generally 80 to 170°C;
In particular, it is preferable to heat at 120 to 150°C for 10 to 40 minutes.

The "pencil hardness" of the above intermediate coating and top coating is determined by applying a test plate coated on a glass plate and hardened (cured coating thickness 30μ).
Hold a pencil (Mitsubishi drafting pencil "Uni") with a flat tip and a sharp 01 angle at a 45 degree angle while keeping it at 0 degrees Celsius.
About 1 hour while pressing firmly against the painted surface so that the thin film does not break.
This is the value when evaluated using the hardness of the hardest pencil that leaves no trace of scratches caused by the pencil when the pencil is moved (3 seconds/hour).

According to the method of the present invention described above, the performance of a multilayer coating film formed on a metal material by electrodeposition coating - intermediate coating coating - barrier coating coating - top coating coating is as follows: I! Compared to films, the finished appearance (e.g., smoothness, clarity, sharpness, water resistance, weather resistance, etc.) is at least the same, but the chipping resistance, corrosion resistance, physical properties, etc. are significantly improved. There is a characteristic that

Next, the present invention will be further explained by Examples and Comparative Examples.

(1) Metal material: Bonderite 4#3030 (Japan Parker Rising■
manufactured by Kasei I;I! (based on zinc phosphate). ! processed steel plate (size 300x90x0.8m).

(2) Electrodeposition paint: (a) Cationic electrocoat paint: Elekron #9200 (
Made by Kansai Paint ■, epoxy polyamide cationic electrodeposition paint, gray color).

(l Anionic electrodeposition paint: Elekronna 7200 (manufactured by Kansai Paint ■, polybutadiene-based anionic electrodeposition paint).

(3) Intermediate paint Near Mirac N-2 Sealer (manufactured by Kansai Paint, amino polyester resin intermediate paint) (4) Barrier coat: Propylene/ethylene copolymer (weight ratio Near 0/3)
Organic solvent solution of resin grafted with 10 parts by weight of maleic acid per 100 parts by weight (static glass transition temperature: 41C1-20°C)
Tensile strength elongation at break: 4 (10%).

(B: Aqueous dispersion obtained by emulsion polymerization of a component consisting of 301@i% styrene and 70% by weight of butadiene according to a conventional method (static glass transition temperature: 48°C, -20% by weight)
Tensile breaking strength elongation rate at °C: 450%).

(0: Organic solvent solution of copolymer consisting of 30% by weight of acrylonitrile, 67% by weight of butadiene and 3% by weight of acrylic acid (static glass transition temperature: 50°C, tensile strength elongation at -20°C: 500%) .

(I): Emulsified water solution of copolymer consisting of isobutylene and normal butylene (static glass transition temperature: 55°C
, tensile strength elongation at -20°C: 600%).

(D: 60% by weight of nonyl acrylate, 20% by weight of 2-ethylhexyl acrylate, 15% by weight of methyl acrylate
An organic solution of a copolymer consisting of 511 parts by weight and 511 parts by weight of hydroxyethyl acrylate (static glass transition temperature: 48°C, tensile strength elongation at -20°C: 370
%).

(D: 60% by weight of hexadecyl acrylate, 20% by weight of 2-ethylhexyl acrylate, 15% by weight of methyl acrylate, and 5% by weight of hydroxyethyl acrylate)
Organic solvent solution of copolymer consisting of % by weight (static glass transition temperature: +4°C) (5) Top coat: (A Near Miracle White (manufactured by Kansai Paint ■, amino-alkyd resin top coat, 1 coat) 1-bake white paint, pencil hardness H (20°C)).

(B: Magiklon Silver (manufactured by LE Nishi Paint ■, aminoacrylic resin topcoat paint, 2-coat, 1-bake silver metallic paint, pencil hardness H (20°C)).

(0: Magikron Clear (manufactured by Kansai Paint ■, aminoacrylic resin-based paint, 2-coat, 1-bake clear paint, pencil hard 1111jH (20°C)).

Examples Comparative Examples The above samples were used to coat steel materials with electrodeposition paint, intermediate coat paint, barrier coat, and top coat paint according to the steps shown in Table 1 below.In Table 1, cationic electrodeposition coated strips, Conditions: Bath solid content concentration 19% by weight, bath temperature 28℃, pH 6.5, load voltage approximately 250■, 18
Power on for 0 seconds.

Anion electrodeposition coating conditions: Bath solid content concentration 12% by weight, bath temperature 30°C, pH 7.8, load voltage approximately 200V, 180
Power on for seconds.

In any of the above cases, after applying @, wash with water and heat at 170℃ for 3
The coating film was cured by baking for 0 minutes. The coating thickness is 20μ based on the cured coating.

The barrier coat was applied with an air spray machine to 6JI based on the dry coating and baked at 120C for 0 minutes.

Both the intermediate and top coats were spray-painted using an electrostatic coating machine, and the film thickness of the intermediate coat was 25 μm based on the cured coating (K), and was baked at 140° C. for 30 minutes.

In topcoat painting, r ICIBJ is a coating system that coats topcoat paint A to a thickness of 35μ based on the cured film and bakes it at 140°C for 30 minutes. Based on the cured coating, the top coat C was applied wet-on-wet to a film thickness of 15 μm, and then a 35 μm film FfEK was applied based on the cured film.
This system hardens the material by baking it at 40°C for 30 minutes.

Summer Performance Test Age Results A coating film property f@ test was conducted using the coated plates coated in the above Examples and Comparative Examples. The results are also listed in Table @1.

〔Test method〕

(*1) Chi-calling resistance: ■Test equipment: Q-G-R Graperometer (product of Q Panel Company) ■Stone to be sprayed: Crushed stone with a diameter of approximately 15-20% (@ Volume of stone to be sprayed) t: Approximately 500 - [Yes] Air pressure for spraying is approximately 4 Kg/cλ ■Temperature during test: Approximately 20°C The test piece is attached to a holding table outside the trial, and spraying of approximately 4 Kp/c11 is approximately 500 with air pressure. - After firing crushed stone onto the test piece, the coating surface condition and salt water spray resistance were carefully evaluated. 960 by Z2371
After applying adhesive cellophane tape to the coated surface for a long time, a salt spray test is carried out. ○) (Good) There are some scratches on the second top coat due to impact.
Only slightly acceptable, 9! No peeling of the applied coating was observed.

C, (slightly poor): There are many scratches on the top coat and intermediate coat due to impact, and there are also occasional peelings of the electrodeposition coat.

× (Poor): Most of the top coat and intermediate coat have peeled off, and the 11th coat on the impact area including the impact area and its surroundings has peeled off. P11. .

@Salt spray resistance C?・No secondary rust, corrosion, peeling of paint, etc. (#, Slight corrosion and peeling of the paint film are observed.

△: m, corrosion and paint peeling are slightly more observed. X: Significant #&S corrosion and paint peeling occurred.

(*2) Impact resistance: Performed in an atmosphere at 0°C according to JIS K5400-1979 6.13.3B method. Weight 500F
A weight was dropped from a height of 50 m to examine damage to the paint film.

(*3) Adhesiveness: According to JIS K5400-1979 6.15 K, make gopan marks on the trunk, apply adhesive tape to the surface, and peel off the tape quickly. evaluate.

(*4) Water resistance: Evaluate the coated surface after immersing it in 40°C water for 1 () day at rfX1.

Procedural correction band, jfe.

August 7, 1986 2 Title of the invention Method for painting metal materials 3 Relationship to the case of the person making the amendment Applicant address 33-1 Kanzaki-cho, Amagasaki City, Hyogo Prefecture 7, 1988
July 2nd (Delivery date: July 29th, 1985) 6. Contents of the amendment As per the engraving and attachment of the specification originally attached to the alt document (no changes to the content)

Claims (1)

[Claims] Apply electrodeposition paint and intermediate paint to the metal material, then
The static glass transition temperature of the formed coating film is 0 to 0 on the intermediate coated surface.
A method for coating metal materials, which comprises applying a top coat after applying a coating composition having a temperature of -75°C.