KR20000062848A - Aqueous solution for treating a metallic surface and metallic material treated therewith - Google Patents

Abstract

An object of the present invention is to provide a water-based surface treatment agent and a surface-treated metal plate for a metal material that provide excellent damage corrosion resistance in addition to excellent corrosion resistance and paint adhesion.

That is, (A) urethane resin and / or acrylic resin, (B) hardening | curing agent, (C) silica particle, (D) polyethylene wax of 0.01-0.2 micrometer of average particle diameters, (E) It is represented by following formula (I) as a dispersing agent A water-based surface treatment agent for metal materials and a surface-treated metal sheet containing a paper compound and water at a specific mutual ratio are used as the solution for the above problems.

In the above formula, R ¹ and R ⁴ are alkyl, alkenyl and the like, R ² is (ethyleneO) _m- (propyleneO) _n , R ³ represents H or sulfonic acid (salt) group.

Description

AQUEOUS SOLUTION FOR TREATING A METALLIC SURFACE AND METALLIC MATERIAL TREATED THEREWITH}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based surface treatment agent for metal materials used to form a resin film having excellent planar corrosion resistance, damaged part corrosion resistance and paint adhesion on the surface of a metal material, and a surface treated metal plate on which such a resin film is formed.

Background Art Conventionally, zinc or zinc-based galvanized steel sheets have been widely used in household telephone products and building materials. Since these steel sheets are insufficient in corrosion resistance and paint adhesion [upper coating property], they are often used for forming or painting such as press work or bending process after chromate conversion treatment or phosphate conversion treatment. Depending on the application, it is often used as it is without painting.

In the case of use without coating, many surface treatment steel sheets, called chromate converted steel sheets, have been applied. However, there are problems such as adhesion of fingerprints and unevenness of color due to the difference in chromate coating amount during molding and assembling. Therefore, in order to solve these problems, an anti-fingerprint steel sheet having an organic coating formed on a chromate coating has been used. The anti-fingerprint steel sheet is formed by forming an organic resin layer having a thickness of about 1 μm after chromate treatment on the surface of a zinc-based plated steel sheet for the purpose of preventing adhesion of fingerprints. In addition to anti-fingerprint, the anti-fingerprint steel sheet requires various coating properties such as corrosion resistance, solvent resistance, paint adhesion, and damage resistance.

Among these performances, in recent years, the demand for damage resistance is increasing. The reason for the damage resistance is required is that the vibrations generated when transporting the product after the molding process cause the moldings or containers (such as cardboard boxes) containing the moldings to rub against each other to scratch the surface of the moldings. This damaged part is inferior in corrosion resistance than a conventional organic coated steel sheet, so quality deterioration cannot be avoided.

Therefore, some techniques regarding the surface treating agent steel plate which considered corrosion resistance and coating adhesion as well as damage resistance are proposed. As such a technique, there exists a method described in Unexamined-Japanese-Patent No. 3-17189, 6-64799, and 6-292859.

Japanese Patent Application Laid-Open No. 3-17189 discloses a method related to a resin coating in which a fluorine-based resin particle and silica particles are mixed with a urethane-modified polyolefin resin. The characteristic of this method is to protect the damaged part by using fluorine resin particles, but in order to uniformly disperse the fluorine resin particles in an aqueous solution, the use of a surfactant is indispensable, and since the surfactant is used, the level of corrosion resistance is increased. Overall, it was impossible to obtain satisfactory corrosion resistance.

Japanese Patent Application Laid-Open No. 6-104799 discloses a method related to a coating film containing a polyester resin, a crosslinking agent, and a polyethylene wax having an average molecular weight of 2000 to 8000. In this method, since the polyester resin is used as the base resin, it was impossible to obtain satisfactory corrosion resistance due to insufficient hydrolysis resistance of the coating itself.

Japanese Patent Application Laid-Open No. Hei 6-292859 discloses a method of coating a film containing spherical polyethylene particles and chain colloidal silica in a resin containing a room temperature crosslinking epoxy resin in a urethane resin having active hydrogen in a molecule. . Colloidal silica has a property of being attached to a solid surface, which is called elongation, which increases the coefficient of friction.In the case of using a chain colloidal silica like this method, damage to the colloidal silica is due to its structural properties. This degrades. Therefore, in this method, spherical polyethylene wax is blended, but since the drying temperature is lower than 100 ° C, the polyethylene wax is buried in the resin coating, resulting in insufficient lubrication, and thus satisfactory corrosion resistance of the damaged part is not obtained.

In this way, the surface-treated steel sheet which is excellent in corrosion resistance and coating adhesiveness and is excellent in corrosion resistance of a damaged part is not obtained in a real tablet.

Moreover, as a (water-based) lubricity paint containing a urethane resin and / or an epoxy resin, silica or silica particles, and a wax containing polyethylene wax, which is used for forming a resin film on a cold rolled steel sheet, a zinc-based galvanized steel sheet or an aluminum metal sheet, Although what is disclosed in Japanese Patent Application Laid-Open No. 5-118550, Patent No. 2719571 or Patent No. 2617838 is known, the present invention described below is different from these inventions in terms of other components and effects of the invention.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art described above, and is a water-based surface treatment agent for metal materials used to form an organic resin film having excellent corrosion resistance, paint adhesion, and especially corrosion resistance, and a surface obtained by using the same. It is an object to provide a treated metal plate.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined about the means for solving the subject which the said prior art has, and as a result, the compound of the specific structure as a urethane resin and / or an acrylic resin, a hardening | curing agent, a silica particle, polyethylene wax of a specific particle diameter, and a dispersing agent By using the water-based surface treating agent containing the present invention, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, this invention is (A) urethane resin and / or acrylic resin, (B) hardening | curing agent, (C) silica particle, (D) polyethylene wax of 0.01-0.2 micrometer of average particle diameters, (E) following formula (I) as a dispersing agent ), And water, components (A) and (B) are dissolved or dispersed in water, components (C) and (D) are dispersed in water, and component (E) Is dissolved in water, the proportion of solids of (A) + (B) is 50 to 95% by weight, and the proportion of solids of (C) is 3 to 40% by weight of the total solids of components (A) to (E). %, (D) + (E) ratio of solid content is 2-20 weight%, and (A) / (B) solid content weight ratio is 4/1-49/1, The water surface treatment agent for metal materials characterized by the above-mentioned. It is about.

[Wherein R ¹ represents an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, R ² represents (EO) _m- (PO) _n ( _wherein E represents an ethylene group and P represents a propylene group) m represents an integer of 5 to 20, n represents 0 or an integer of 1 to 10, and R ³ represents a hydrogen atom or SO ₃ M (wherein M represents a hydrogen atom, an alkali metal ion or an ammonium ion). R ⁴ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms.

It is preferable that the ratio of solid content of (E) with respect to solid content of (D) + (E) is 10-40 weight%, It is preferable that the glass transition temperature of component (A) exists in the range of -40-0 degreeC, It is preferable that component (B) is an epoxy resin, and it is more preferable that component (B) is an epoxy resin which has 3 or more epoxy groups in 1 molecule.

In addition, the present invention has a chromate coating layer of 3 to 100 mg / m ² in terms of metal chromium as a first layer on the surface of the metal material, 0.3 formed by applying and drying the water-based surface treatment agent for the metal material as a second layer It has a resin coating layer of -3.0 g / m <^2> , It is related with the surface-treated metal plate characterized by the above-mentioned.

Hereinafter, the configuration of the present invention will be described in detail.

A first feature of the present invention is to blend a suitable type of resin as a base resin in a certain weight ratio. As resin, it is necessary to set it as the structure which the balance of corrosion resistance, abrasion resistance, and chemical resistance was taken. Therefore, in this invention, (A) urethane resin and / or acrylic resin are used, This resin is melt | dissolved or disperse | distributed in this water-based surface treating agent for metal materials.

The urethane resin used in this invention is manufactured using the raw material which consists of four components of a compound which has a polyol component, a polyisocyanate component, a carboxylic acid component, and three or more active hydrogens.

Examples of the polyol component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4- Ethylene oxide and / or propylene oxide adducts of low molecular weight polyols such as butylene glycol, hexamethylene glycol, hydrogenated bisphenol-A, bisphenol-A, trimethylolpropane, glycerin, polyethylene glycol, polypropylene glycol, polyethylene / poly Polyether polyols such as propylene glycol, polycaprolactone polyol, polyolefin polyol, polybutadiene polyol, these polyols and succinic acid, glutamic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid Obtained by reaction with a polybasic acid such as hexahydrophthalic acid and having a hydroxyl group at the terminal. There may be mentioned polyester polyols, such as Li.

Examples of the isocyanate component include aliphatic, alicyclic and aromatic polyisocyanates, preferably tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexylene diisocyanate , 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 1 , 5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4 ' -Diphenylmethane diisocyanate, phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, etc. are mentioned. All. Among these, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4 ' When an aliphatic or alicyclic polyisocyanate such as dicyclohexyl methane diisocyanate or isophorone diisocyanate is used, a film having excellent corrosion resistance and chemical resistance is obtained.

As a carboxylic acid component, 2, 2- dimethyl roll propionic acid, 2, 2- dimethyl roll butyric acid, 2, 2- dimethyl roll valeric acid, etc. are mentioned.

Examples of the compound having three or more active hydrogens include melamine, diethylenetriamine, trimethylolpropane, pentaerythritol, glycerin and ethylene oxide and / or propylene oxide adducts thereof.

And it is naturally possible to add further the compound (chain extender) which has two active hydrogens normally used as needed at the time of urethane resin manufacture. Examples of such chain extenders include polyols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol or ethylene oxide and / or propylene oxide adducts thereof, ethylenediamine, propylenediamine, hexamethylenediamine, Tolylenediamine, xylylenediamine, diaminodiphenylmethane, diaminodicyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydra Amines such as jides, and the like.

The usage-amount of the raw material of the urethane resin used by this invention is 30-70 weight part of polyol components, Preferably it is 35-65 weight part, 20-50 weight part of polyisocyanate components, Preferably it is 25- with respect to 100 weight part of urethane resins. It is 40 weight part, 0.5-10 weight part of carboxylic acid components, Preferably 1-8 weight part, 0.1-5 weight part of compounds which have 3 or more active hydrogens, Preferably it is 0.2-3 weight part. And the usage-amount of the chain extending agent at the time of using is 1-15 weight part with respect to 100 weight part of urethane resins, Preferably it is 3-10 weight part.

There is no restriction | limiting in particular about the manufacturing method of the urethane resin used by this invention, Although a well-known method can be used, It is preferable to manufacture by the prepolymer method used industrially. In the prepolymer method, a polymer obtained by reacting a polyol component, a polyisocyanate component, a carboxylic acid component, and a compound having three or more active hydrogens in an organic solvent which is inert to reaction and has a high affinity for water contains a neutralizing agent and a chain extender. A urethane resin is manufactured by disperse | distributing in aqueous solution.

Examples of the organic solvent include acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethyl acetate and the like. And as said neutralizing agent, inorganic bases, such as organic amine, such as trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyl diethanolamine, and triethanolamine, sodium hydroxide, potassium hydroxide, ammonia, are mentioned, for example. .

Although there is no restriction | limiting in particular about the molecular weight of the urethane resin obtained, It is preferable that it is 5,000 or more.

Next, the acrylic resin used by this invention shall mean the copolymer obtained by copolymerizing (meth) acrylic acid and the monomer which has an ethylenic double bond different from this.

Examples of such monomers include maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth ) Allyl ether, 3-hydroxypropyl (meth) allyl ether, 4-hydroxybutyl (meth) allyl ether, allyl alcohol, glycidyl (meth) acrylate, 2- (1-aziridinyl) ethyl acrylate , Vinyltrimethoxysilane, vinyltriethoxysilane, allyl glycidyl ether, imol methacrylate, acryloyl morpholine, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylic Amide, N-ethoxymethyl (meth) acrylamide, N-butoxymethyl (meth) Acrylamide, (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, vinyl formate, vinyl acetate, vinyl butyrate, acrylic acid Vinyl, styrene, α-methylstyrene, t-butylstyrene, vinyltoluene, (meth) acrylonitrile, vinyl cinnamic acid, (meth) acryloxyethyl phosphate, bis- (meth) acryloxyethyl phosphate, (meth) acrylic And oxyethylphenyl azide phosphate.

It is preferable that it is 1-20 weight part with respect to 100 weight part of acrylic resin used by this invention, and, as for the usage-amount of (meth) acrylic acid, it is more preferable that it is 2-15 weight part.

Although there is no restriction | limiting in particular about the manufacturing method of the acrylic resin used by this invention, All the emulsion polymerization method and monomer which disperse | distribute the surfactant and monomer which are called emulsifiers in water uniformly in water, and advance a polymerization reaction after monomer is emulsified all Or in industrial bases such as suspension polymerization, in which a monomer is dispersed in a solvent (such as water) which is almost insoluble, and the polymerization reaction is advanced in a small drop of the monomer suspended using a polymerization initiator that is poorly soluble in the solvent and soluble in the monomer. It is preferable that it is an effective method.

There is no restriction | limiting in particular about the molecular weight of acrylic resin used by this invention, When measured by a gel permeation chromatography, it is preferable that it is about 10,000 to 1 million.

It is preferable that it is -40 degreeC-0 degreeC, and, as for (A) resin used by this invention, it is more preferable that it is -40 degreeC --5 degreeC. If the glass transition temperature is lower than −40 ° C., the blocking resistance of the resulting film is poor, which is not preferable. In addition, the film physical properties of the resin tend to change greatly at the glass transition temperature. Usually, the temperature at which the product after the molding process is handled is in the range of 10 ° C to 50 ° C. If there is a glass transition temperature in this temperature range, the film physical properties of the resin change depending on the temperature, and the damage resistance of the film is caused. There is a high possibility of this deterioration. Furthermore, when the glass transition temperature exceeds 50 ° C., the film formation property of the film is lowered, so it is necessary to increase the drying temperature of the treatment agent and it is not economically useful. Therefore, it is preferable to make the glass transition temperature of resin into the range of -40 degreeC-0 degreeC.

Next, the measuring method of the glass transition temperature of resin is demonstrated. For measuring glass transition temperature: Measuring apparatus: Leorograph Fu Solid S-1 manufactured by Toyo Seiki Co., Ltd. of Japan, Test Specimen: Film thickness of 100 μm, width of 8 mm, length of 30 mm, dried at 100 ° C. for 30 minutes. The film was used and measured at a frequency of 100 Hz to obtain from the inflection point of the elastic loss rate.

In this invention, in order to derive the characteristic of (A) resin further, the (B) hardening | curing agent is mix | blended. As (B) hardening | curing agent used by this invention, an isocyanate compound, an aziridine compound, and an epoxy resin are preferable, and the epoxy resin which has three or more epoxy groups in 1 molecule is more preferable. The resin used in the present invention has a carboxyl group, and since the resin structure obtained by the reaction of this carboxyl group with a functional group of the curing agent (isocyanato group, aziridinyl group, epoxy group, etc.) forms a three-dimensional network structure, The performance is dramatically improved. As such epoxy resin, a novolak-type epoxy resin, the epoxy resin obtained by reaction of the compound which has three or more OH groups, and epichlorohydrin, etc. are mentioned. There is no restriction | limiting in particular about the molecular weight of the said epoxy resin used by this invention, When measured by a gel permeation chromatography, it is preferable that it is 3,000 or less.

The epoxy resin is dissolved or dispersed in water in the water-based surface treatment agent of the present invention.

As for solid content weight ratio (A) / (B) of (A) urethane resin and / or acrylic resin used by this invention, and (B) hardening | curing agent, 4/1-49/1 are preferable, and 10/1-40/1 This is more preferable. When the ratio of (A) / (B) is less than 4/1, the resin (A) cannot exhibit sufficient properties, and since unreacted curing agents remain and play a plastic role, the corrosion resistance is preferable. Not. On the other hand, when the ratio of (A) / (B) exceeds 49/1, the compounding effect of the curing agent is insufficient and satisfactory corrosion resistance cannot be obtained.

Of (A) + (B) to solids (hereinafter, referred to as total solids) of components (A) + (B) + (C) + (D) + (E) of the water-based surface treatment agent of the present invention It is necessary that the ratio of solid content is 50 to 95 weight%, and it is preferable that it is 60 to 85 weight%. When this ratio is less than 50 weight%, since the water resistance of the film itself falls, it is unpreferable. On the other hand, when this ratio exceeds 95 weight%, since corrosion resistance of a damaged part falls, it is unpreferable.

The (C) silica particles used in the present invention are not particularly limited in terms of particle size, shape and type, but the particle size is preferably in the range of 3 to 30 nm. Silica particles are dispersed in water in the water-based surface treatment agent of the present invention. The ratio of the silica particles to the total solids needs to be 3 to 40% by weight, preferably 10 to 30% by weight. When this ratio is less than 3 weight%, the improvement of corrosion resistance is lacking, On the other hand, when it exceeds 40 weight%, since the binder effect of a resin component (A) decreases and corrosion resistance falls, it is unpreferable.

Although the polyethylene wax (D) used by this invention is mix | blended in order to improve the level of damage resistance, the average particle diameter needs to be 0.01-0.2 micrometer, and it is preferable that it is 0.05-0.18 micrometer. In general, the coefficient of friction used as an indicator of lubricity tends to decrease as the wax particle diameter increases. However, the friction coefficient and the damage resistance do not necessarily coincide with each other, but the relationship between the sliding coefficient (or sliding distance) and the friction coefficient (abrasion resistance) is important. MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the relationship between the average particle diameter of a wax, and a sliding frequency, the present inventors discovered that excellent damage resistance was obtained by making the average particle diameter of a wax into 0.01-0.2 micrometer. The average particle diameter of the wax depends on the melt viscosity of the wax and the performance of the machine used to disperse it. Therefore, if the average particle diameter of the wax is less than 0.01 µm, it is not economical to use a higher performance machine. On the other hand, when it exceeds 0.2 micrometer, the wax which protruded from the film surface easily disappears at the time of sliding, and as a result, continuous sliding property falls, and it is unpreferable.

And in this invention, although there is no restriction | limiting in particular about the molecular weight and melting | fusing point of (D) polyethylene wax, The range of 5-50 is preferable and, as for an acid value, the range of 10-30 is more preferable. If the acid value is less than 5, the wax and the resin are hardly compatible with each other, and therefore, the wax is completely oriented on the surface of the coating during formation of the coating, which is not preferable because it causes damage resistance and coating film degradation. On the other hand, when the acid value exceeds 50, the hydrophilicity of the wax becomes strong, so that the activity of the wax itself is lowered and damage resistance is lowered, which is not preferable.

(E) dispersing agent used by this invention is a compound represented by said Formula (I).

It is preferable that R <^1> is a C5-C20 alkyl group or a C2-C5 alkenyl group from above, As m, it is preferable that it is an integer of 8-20, As n, It is preferable that it is an integer of 0 or 1-5, As R <^3> It is preferable that it is a hydrogen atom or SO ₃ NH ₄ , and R ⁴ is preferably a hydrogen atom or an alkenyl group having 2 to 4 carbon atoms.

The polyethylene wax (D) used by this invention is used as a water dispersion prepared normally using the (E) dispersing agent. There is no restriction | limiting in particular about the dispersion method of polyethylene wax, What is necessary is just a method used industrially.

Moreover, the average particle diameter of said (D) polyethylene wax is a value in this water dispersion.

It is preferable that it is 5-40 weight%, and, as for the ratio of solid content of (E) with respect to solid content (that is, solid content of (D) + (E)) of the said water dispersion, it is more preferable that it is 5-30 weight%. If the ratio is less than 10% by weight, the dispersion stability of the polyethylene wax is insufficient. On the other hand, when the said ratio exceeds 40 weight%, since the water resistance of the film obtained using the water-based surface treating agent obtained falls, it is unpreferable.

The ratio of the water dispersion to the total solids of the water-based surface treatment agent of the present invention (ie, solids of components (A) + (B) + (C) + (D) + (E)) is (D) + (E) It is necessary to be 2-20 weight% as a ratio of solid content of, It is preferable that it is 3-15 weight%, It is more preferable that it is 3-10 weight%. If the ratio is less than 2% by weight, the effect of improving the damage resistance is insufficient. On the other hand, if the ratio exceeds 20% by weight, the coat coatability is lowered, which is not preferable.

In the water-based surface treatment agent of the present invention, as an optional component, a surfactant called a wettability improving agent for forming a uniform coating on the surface to be coated, a conductive material for improving welding, a coloring pigment for improving the designability, and a film forming property You may contain the solvent etc. for improvement.

The water-based surface treatment agent for metal materials of the present invention by mixing, dissolving, and dispersing the components (A), (B), (C) and the water dispersion [ie, (D) + (E)] and the optional components in water. Can be obtained. Although there is no restriction | limiting in particular in the order of addition of components, It is suitable to mix, for example by stirring using a propeller type stirrer.

It is preferable that it is in the range of 5-50 weight% of solid content concentration, and, as for the water type surface treating agent of this invention obtained, it is more preferable to exist in the range which is 5-40 weight%. If the solid content concentration is less than 5% by weight, the drying time becomes long, which is not preferable. On the other hand, when solid content concentration exceeds 50 weight%, the viscosity of a processing agent itself is high and there exists a possibility of causing trouble in handling.

Examples of the metal material (material) to which the water-based surface treatment agent of the present invention is applied include metal plates such as cold rolled steel sheet, zinc-based plated steel sheet, aluminum-based plated steel sheet, and aluminum sheet.

Although the water-based surface treating agent of the present invention may be applied directly to such a metal material, in order to fully exhibit the effects of the present invention, first, a chromate coating is formed by a chromate treatment by a conventional method, and the water-based surface treating agent of the present invention thereon. It is preferable to apply a resin to form a resin film.

In the chromate treatment, electrolytic chromate to form a chromate film by electrolysis, reaction chromate to form a film by reaction with a raw material, and then wash the excess treatment liquid and apply the treatment liquid to the object to be dried without washing with water. There is a coating type chromate which forms a film by forming a film. Any treatment method can be employed in the present invention.

The resin coating is formed by applying the water-based surface treatment agent of the present invention at 10 to 50 ° C. and drying the reaching plate temperature at 60 to 200 ° C. on the base film formed by the chromate treatment. As the coating method, a conventional method such as a roll coater method, an immersion method, an electrostatic coating method, or the like can be used.

The surface-treated metal plate of the present invention obtained by such a two-stage treatment has a chromate coating layer of 3 to 100 mg / m ² in terms of metal chromium as the first layer on the surface of the metal material, and as the second layer for the metal material of the present invention. It is a surface-treated metal plate characterized by having a resin coating layer of 0.3-3.0 g / m <^2> formed by apply | coating and drying a water type surface treating agent. It is preferable that it is 3-50 mg / m <^2> in conversion of metal chromium, and, as for the weight of a chromate coating layer, it is more preferable that it is 5-40 mg / m <^2> .

If the chromium adhesion amount is less than 3 mg / m ² , the improvement of corrosion resistance is insufficient. On the other hand, if the amount of chromium adhesion exceeds 100 mg / m ² , the effect of improving the corrosion resistance is saturated, which is not economical. If the dry resin film amount is less than 0.3 g / m ^{2, the} effect of improving corrosion resistance is insufficient, and if it exceeds 3.0 g / m ² , the effect of improving corrosion resistance is saturated and not economical.

The resin coating formed by coating and drying the water-based surface treatment agent of the present invention, and the surface-treated metal plate is excellent in the flat part corrosion resistance, damage part corrosion resistance and coating adhesion. There is no restriction | limiting in particular as a top coat paint apply | coated on a resin film, For example, a room temperature dry type melamine alkyd paint, a bake-type melamine alkyd paint, an acrylic resin paint, an ultraviolet curable resin paint etc. are mentioned.

EXAMPLE

Hereinafter, this invention is demonstrated concretely using an Example, a manufacture example, and a comparative example. These examples are described for the purpose of illustrating the present invention and are not intended to limit the invention.

[Creation of trial version]

(1) Test materials

Commercial materials shown below were used as test materials.

Electro Galvanized Steel Sheet (EG)

Plate thickness 0.8 mm, adhesion amount = 20/20 (g / m ² )

Galvanized Steel Sheet with 5% Aluminum (GF)

0.8 mm thick, 90 = 90 (g / m ² )

Aluminum Plate (AL)

Board thickness 1.0mm, 5182 system

(2) degreasing treatment

It was degreased with fine cleaner 4336 (registered trademark of Nippon Parkarizing Co., Ltd., Japan) which is each of the above-described silicate-based alkali degreasing agents. The solution was sprayed at a concentration of 20 g / L and a temperature of 60 ° C. for 2 minutes, and then washed with tap water.

(3) not processed

(3-1) Reactive Chromate Chemical Treatment (Material: EG, GF)

A test plate was constructed by spraying at a liquid temperature of 50 ° C. for 5 seconds using Jinchromu 357 (trademark: manufactured by Nippon Parkarizing Co., Ltd.), washed with tap water, and air dried.

(3-2) Coating type chromate conversion treatment (material: EG, GF)

A test plate was constructed by immediately applying at 40 ° C an atmospheric temperature without applying water by using a roll coater method, using Jinromu 1300AN (registered trademark: Nippon Parkarizing Co., Ltd.). And the reached plate temperature at this time is 100 degreeC.

(3-3) Reactive Chromate Chemical Treatment (Material: AL)

A test plate was prepared by spraying at a liquid temperature of 50 ° C. for 5 seconds using Jinromu 713 (trademark: manufactured by Nippon Parkarizing Co., Ltd.), washed with tap water, and air dried.

[Preparation of Water-Based Surface Treatment Agent]

At room temperature, the resins of Table 1, the curing agents of Table 2, the silica particles of Table 3, and the wax water dispersions of Table 4 were mixed in this order with stirring using a propeller stirrer, distilled water was added to adjust the solid content concentration shown in Table 5 The water surface treating agent of the Example and the water surface treating agent of the comparative example shown in Table 6 were prepared. And the wax water dispersion was prepared by putting all the wax, compound (I), and water shown in Table 4 into an autoclave, heating and stirring to the temperature of 130 degreeC-140 degreeC.

[Application Method of Water-Based Surface Treatment Agent to Test Plate]

Each water-based surface treatment agent prepared above was applied to each of the test plates described above using a bar coater, and dried at an ambient temperature of 240 ° C. for 10 seconds. The reached plate temperature at this time is 100 degreeC. The adhesion amount was adjusted by appropriately changing the solid content concentration and the type of bar coater of the composition.

[Paint plate performance test]

(1) flat part corrosion resistance

The salt spray test according to JIS-Z2371 was performed for 240 hours for EG materials, 480 hours for GF materials, and 600 hours for AL materials, and white rust (white rust) was observed and evaluated according to the following criteria.

<Evaluation standard>

◎: White rust generating area rate is less than 3% of the total area

: White rust generating area rate is more than 3% and less than 10% of the total area

: White rust generating area rate is more than 10% and less than 30% of the total area

×: white rust-generating area rate is more than 30% of total area

(2) Damaged part corrosion resistance

The specimen is cut to a size of 30 mm x 300 mm and subjected to a draw bead test (bead tip 1 mmR, bead height 4 mm, die shoulder 1 mmR, compressive load 500 kg, temperature 30 ° C). The salt spray test according to JIS-Z2371 was conducted on the sliding part of the test piece for 120 hours for EG material, 240 hours for GF material, and 360 hours for AL material, and observed white rust (white rust). Evaluation was made based on the criteria.

<Evaluation standard>

◎: White rust generating area rate is less than 3% of the total area

: White rust generating area rate is more than 3% and less than 10% of the total area

: White rust generating area rate is more than 10% and less than 30% of the total area

×: white rust-generating area rate is more than 30% of total area

(3) Paint adhesion

Melamine alkyd paint (registered trademark: Amirak # 1000, manufactured by Nishiso Paint Co., Ltd.) is applied so that the film thickness after baking is 25 µm and baked at 125 ° C. for 20 minutes. Using a test piece after 24 hours of baking, 100 sheets of 1 mm checkerboard eyes were drawn in accordance with JIS-Z5400, and then the coating film was peeled off with cellophane and evaluated according to the following criteria.

◎: No coating film peeling, remaining number of coating film

: Very slight peeling of paint, 100 remaining film

: 95 ~ 99 paint film remaining

×: 94 films or less

The test results are shown in Tables 7 and 8. In Examples 1 to 21 using the water-based surface treatment agent of the present invention, any of the flat portion corrosion resistance, damage portion corrosion resistance, and paint adhesion was satisfactory. On the other hand, in Comparative Examples 1 to 9 using water-based surface treatment agents outside the scope of the present invention, at least two performances of the flat part corrosion resistance, the damaged part corrosion resistance, and the paint adhesion were poor.

Table 1 Resin Used in Examples and Comparative Examples

Suzy Product Name maker Resin Glass transition temperature Solids concentration Claim Reason A1 Super flex 107M 第一 工業 製藥 (株) urethane -40 ℃ 25% A2 Ade Carbon Tighter HUX-580 電 化 電 工業 (株) urethane -14 ℃ 62% A3 Buraimaru K-3 ROHM & HAAS acryl -27 ℃ 46% A4 Buraimaru NW-1715 ROHM & HAAS acryl -6 ℃ 44% A5 Byronaru MD-1930 東洋 紡 績 (株) ester -10 ℃ 30% × Different resin system

Table 2 Curing Agents Used in Examples and Comparative Examples

Hardener Product Name maker Functional group Solids concentration B1 Dinakoru EX-512 Nagase Chemical Epoxy 100% B2 Elastron BN-69 第一 工業 製藥 (株) Isocyanato 40%

Table 3 Silica Used in Examples and Comparative Examples

Silica Product Name maker Solids concentration C1 Snow Tex-N Nippon Chemical Engineering Co., Ltd. 20% C2 Snow Tex-O Japanese Chemical Industry 20%

Table 4 Wax Water Dispersions Used in Examples and Comparative Examples (20% solids concentration)

Wax Compound (1) Average particle size μm Claim Type ^{* 1} Compounding amount ^{* 2} R ¹ R ² R ³ R ⁴ Compounding amount ^{* 2} m n W1 Sanji Hiwax 4202E Shinga 17 75 C ₉ H _19- 12 0 -H -CH = CHCH ₃ 25 0.08 W2 Sanji Hiwax 2203A Shinga 30 95 C ₁₈ H _37- 20 0 -SO ₃ NH ₄ -H 5 0.12 W3 Sanji Hiwax 4202E Shinga 17 90 C ₈ H _17- 10 5 -H -H 10 0.15 W4 Sansei High Wax 4051E Shinga 12 80 CH ₂ = CHCH _2- 10 5 -H -H 20 0.15 W5 Sanji Hiwax 4202E Shinga 17 85 C ₉ H _19- 12 0 -H -H 15 0.45 × ^{* 3} W6 Sanji Hiwax NP055 Shinga 0 90 C ₁₈ H _37- 20 0 -SO ₃ NH ₄ -H 10 0.10 × ^{* 4}

* 1: W1 to W5 are polyethylene wax, W6 is polypropylene wax

* 2: The numerical value of the compounding amount is the weight percent of solids based on the total solids of the wax water dispersion.

* 3: particle size is out of range

* 4: Wax type is out of range

Table 5 Water-Based Surface Treatment Agents Used in Examples

* 1: Values in () are the solids weight% relative to the total solids of the water-based surface treatment agent.

Table 6 Water-Based Surface Treatment Agents Used in Comparative Examples

* 1: Values in () are the solids weight% relative to the total solids of the water-based surface treatment agent.

Table 7 Test Levels and Film Performance of Examples

* 1: metal chromium equivalent weight * 2: dry resin film weight

Table 8 Test Levels and Film Performance of Comparative Examples

* 1: metal chromium equivalent weight * 2: dry resin film weight

As described above, by applying the water-based surface treatment agent of the present invention to the surface of the metal plate subjected to the chromate treatment, it is possible to obtain a surface-treated metal plate excellent in flat portion corrosion resistance, damage portion corrosion resistance and paint adhesion.

Claims (6)

(A) Urethane resin and / or acrylic resin, (B) hardening | curing agent, (C) silica particle, (D) polyethylene wax of 0.01-0.2 micrometer of average particle diameters, (E) The compound represented by following formula (I) as a dispersing agent , And water, components (A) and (B) are dissolved or dispersed in water, components (C) and (D) are dispersed in water, and component (E) is dissolved in water 50-95 weight% of ratio of solid content of (A) + (B) with respect to the total solid of components (A)-(E), 3-40 weight% of ratio of solid content of (C), (D) + The ratio of solid content of (E) is 2-20 weight%, (A) / (B) solid content weight ratio is 4/1-49/1, The water-based surface treatment agent for metal materials. [Wherein R ¹ represents an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, R ² represents (EO) _m- (PO) _n ( _wherein E represents an ethylene group and P represents a propylene group) m represents an integer of 5 to 20, n represents 0 or an integer of 1 to 10, and R ³ represents a hydrogen atom or SO ₃ M (wherein M represents a hydrogen atom, an alkali metal ion or an ammonium ion). R ⁴ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. The water-based surface treatment agent for metal materials according to claim 1, wherein the ratio of the solid content of (E) to the solid content of (D) + (E) is 5 to 40% by weight. The water-based surface treatment agent for a metal material according to claim 1 or 2, wherein the glass transition temperature of the component (A) is in the range of -40 to 0 ° C. The water-based surface treatment agent for a metal material according to any one of claims 1 to 3, wherein the component (B) is an epoxy resin. The water-based surface treatment agent for a metal material according to claim 4, wherein the component (B) is an epoxy resin having three or more epoxy groups in one molecule. The water-based surface treatment agent for metal materials according to any one of claims 1 to 5, having a chromate coating layer of 3 to 100 mg / m ² in terms of metal chromium as a first layer on the surface of the metal material. And a resin coating layer of 0.3 to 3.0 g / m ² formed by coating and drying.