JP2002212748A - Non-chromate type surface treated metallic sheet and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weldable surface treated metallic sheet which has various excellent performances with respect to the grade of the surface appearance of the steel sheet such as galling resistance on pressing, fingerprint resistance and resistance to unevenness of dew condensation as well as corrosion resistance and coating adhesion without incorporation of harmful chromium such as hexavalent chromium. SOLUTION: The surface treated metallic sheet has a film layer containing an aqueous resin, a silane coupling agent and a phosphoric component as a substrate treatment layer. The upper layer thereof is provided with an upper film layer consisting of a 100 pts.wt. organic resin and 1 to 50 pts.wt. particulates silica as solid contents, and the coating weight of the upper film layer is 0.1 to 5 g/m2. The substrate treatment layer may further contain particulate silica and a fluoride having etching properties, and the upper film layer may further contain a lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-chromate type surface-treated metal sheet having excellent corrosion resistance. Furthermore, corrosion resistance,
The present invention relates to a non-chromate type surface treated metal sheet having excellent press galling resistance and weldability. In particular, the present invention relates to the field of surface treatment using a zinc-based plated steel sheet that is frequently used in automobiles, home appliances, building material products, and the like.

[0002]

2. Description of the Related Art Conventionally, galvanized steel sheets or galvanized steel sheets have suffered from white rust on the surface in an atmosphere containing salt such as seawater or a high-temperature and high-humidity atmosphere, significantly impairing the appearance, and having a problem with respect to the base steel surface. Although the rust preventive power is reduced, a chromate-based rust preventive agent has conventionally been used to prevent this white rust.
No. 70 discloses a resin-based treating agent containing a water-dispersible chromium compound and water-dispersible silica in an olefin-α, β-ethylenically unsaturated carboxylic acid copolymer resin dispersion.

On the other hand, in recent years, in particular, in the home appliance industry, those which are applied without coating are increasing from the viewpoint of saving steps and costs, and not only corrosion resistance and paint adhesion but also galling resistance, fingerprint resistance, and fingerprint resistance are improved. The required level of various performances such as dew condensation unevenness on the surface appearance quality of a steel sheet is increasing.
In order to respond to such performance demands from consumers, a coated metal plate in which an organic composite film based on a special resin is formed on a plated steel plate subjected to a chromate treatment has been developed. For example, Japanese Patent Publication No. 4-14191 discloses that an organic composite film in which a colloidal sol of a specific fine particle size is additionally adjusted on an aqueous organic resin is formed on a plated steel sheet subjected to a chromate treatment, and the performance such as corrosion resistance and fingerprint resistance is improved. A method of manufacturing a surface-treated steel sheet with improved properties is disclosed. Also, JP-A-3-394.
No. 85 discloses that after a chromate treatment is performed on a zinc-based plated steel sheet, silica and a glass transition point (T
(g point) of 0.3 to 3.0 g / m ² as a dry weight is coated with a coating material in which wax having a temperature of 40 ° C. or more is dispersed. Also, JP-A-3-28380 discloses that
After performing chromate treatment on electrogalvanized steel sheet,
A paint comprising a carboxylated polyethylene resin and a Teflon (trademark) lubricant is 0.5 to 4.
A lubricated steel sheet coated with 0 g / m ² is disclosed. Furthermore, in order to meet the demands of consumers who require severe galling resistance, such as deep drawing workability, a surface treated steel sheet with improved lubricity by adding a solid lubricant to the organic film was developed. . For example, JP-A-6-173037 discloses a steel sheet having a lubricating film obtained by adding silica and a polyolefin wax to an ether / ester type urethane resin and an epoxy resin.

Japanese Patent Publication No. 4-14191 discloses a surface-treated steel sheet having an excellent balance of performance such as corrosion resistance, paint adhesion, fingerprint resistance and dew condensation resistance, and is currently one of the main products for home appliances. Has been used as. When importance is placed on galling resistance during press working, scratch resistance during handling, abrasion resistance during transportation, and the like, this is disclosed in JP-A-3-39485 and JP-A-3-28380. Such technologies are widely used.
Further, in the case of molding under extremely severe pressing conditions such as deep drawing and hard ironing, the technique disclosed in Japanese Patent Application Laid-Open No. 6-173037 is used.

A surface-treated steel sheet having such a chromate-based coating or a surface-treated steel sheet having an organic composite coating on the chromate-based coating has the best corrosion resistance among known surface-treated steel sheets. Has been recognized as. Nevertheless, chromate-based coatings contain hexavalent chromium, which is known to be a harmful element, and there is an increasing demand for surface-treated metal plates that do not contain hexavalent chromium. Also, in order to improve the adhesion and corrosion resistance of the upper organic composite film, known electrolytic chromates and reactive chromates mainly composed of trivalent chromium, which are often used as a coating base treatment, are slightly hexavalent. Since it may contain chromium, it may be difficult to use it in the future. As described above, chromate-based treatment is used as a primary rust preventive treatment for steel sheets and plated steel sheets, and as a base treatment for painting and coating. Is desired.

As a surface treatment technique that does not contain chromium,
There is a phosphate treatment such as a zinc phosphate treatment. However, phosphate treatment is somewhat inferior to primary chromate treatment as a primary rust preventive treatment, and chromium sealing is required to ensure corrosion resistance even as a coating base, as an alternative technology to chromate treatment. Is not enough. In order to solve these problems, JP-A-5-195244 and JP-A-7-145486 disclose,
A treatment method for forming a coating layer containing no chromium has been proposed, but all have the same performance as those subjected to conventional chromate treatment, that is, satisfying the same corrosion resistance and paint adhesion as chromate treatment. Not in.

JP-A-11-106945 discloses a non-chromate type rust preventive agent containing a water-soluble polymer, phosphoric acid, and a silane coupling agent, and a treatment method for forming a treated film on a metal surface by one-layer treatment. Although it is disclosed, it does not satisfy the corrosion resistance of the processed part equivalent to the one subjected to chromate treatment, the press galling resistance equivalent to the above-mentioned organic composite film coated steel sheet containing organic resin and silica as main components, and the like. .

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to have a corrosion resistance more than that of chromate treatment, which is effective for a metal plate such as a zinc or zinc alloy plated steel plate. An object of the present invention is to provide an inexpensive non-chromate type rust-proof metal plate. In addition, inexpensive welding that can meet the required level of various performance requirements for steel sheet surface appearance quality such as corrosion resistance and paint adhesion as well as galling resistance, fingerprint resistance, uneven condensation, etc. It is an object of the present invention to provide a non-chromate type anti-rust treated metal sheet.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, not only corrosion resistance and paint adhesion, but also galling resistance, fingerprint resistance, and condensation unevenness resistance have been studied. It was found that it was effective to apply a film composed of organic resin and fine silica to the upper layer in order to improve various performances on the surface appearance quality of the steel sheet, and found that the organic resin, silane coupling agent, and phosphoric acid It is possible to improve the adhesion between the upper layer coating and the metal plate such as zinc or zinc alloy-plated steel plate by performing the base treatment combining the components. No corrosion resistance equivalent to or higher than that of chromate treatment was found.

That is, the non-chromate type rust-preventive metal plate of the present invention has a coating layer containing an aqueous resin, a silane coupling agent and a phosphoric acid component as an undercoating layer. 1 to 50 parts by weight of organic resin
0.1 to 5 g of upper layer coating containing parts by weight of fine silica
/ M ² . The undercoating layer contains 0.1 to 3000 parts by weight of a silane coupling agent and 100 parts by weight of an aqueous resin as a solid component, and a phosphoric acid component (P
(As an anion component) in an amount of 0.01 to 100 parts by weight.

The above-mentioned undercoating layer is, in terms of solid content, at least one of 1 to 2000 parts by weight of fine silica and 0.1 to 1000 parts by weight of etchable fluoride based on 100 parts by weight of the aqueous resin. Can be further contained.
The silane coupling agent contained in the undercoat layer preferably has a glycidyl ether group.

The amount of the undercoating layer to be applied is 5 to 500 mg.
/ M ² . Galling resistance during pressing,
Scratch resistance during handling, abrasion resistance during transportation, if you want to further improve, the upper layer coating, in terms of solids content,
The lubricant may further contain 1 to 30 parts by weight based on 100 parts by weight of the organic resin.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present invention, without using a chromate-based treatment agent, corrosion resistance including the processed part more than chromate-based treatment, excellent coating adhesion, galling resistance during pressing, fingerprint resistance, condensation unevenness resistance, etc. It successfully responded to the needs of high surface appearance quality.

[0014] Not only the corrosion resistance and the paint adhesion of the metal plate including the zinc or zinc alloy-plated steel plate including the processed part, but also the galling resistance at the time of pressing, the fingerprint resistance, the condensation unevenness resistance, etc.
There have been many reports that a film composed of an organic resin and fine silica particles is effective in improving various performances on the surface appearance quality of a steel sheet.
It was premised that the undercoat had a chromate treatment and the adhesion between the upper coating and the metal plate was ensured.

Conventionally, there has been reported a method of adding a silane coupling agent or a phosphoric acid component to a treatment agent for forming a film in order to improve the adhesion to a base metal by a single treatment. There is a problem in terms of life such as gelation, and a problem of performance deterioration such as workability and corrosion resistance due to the film becoming hard and brittle, particularly corrosion resistance of a processed portion. Also, with this method, it is extremely difficult to ensure the same high level of adhesion to the underlying metal as when there is a chromate treatment on the substrate, and to develop higher quality such as corrosion resistance and press galling resistance. There are limits to gender.

On the other hand, the present invention is characterized in that it is a two-layer treatment of an undercoating treatment combining an aqueous resin, a silane coupling agent and a phosphoric acid component and an upper coating film composed of an organic resin and fine silica particles. . By combining the aqueous resin, the silane coupling agent, and the phosphoric acid component at the same time, the adhesion between the underlying metal and the upper layer film can be dramatically improved. The strong adhesion guarantee also contributes to the improvement of corrosion resistance due to the shielding effect of corrosion factors. The phosphoric acid component has an effect of etching the surface of the underlying metal, and has a great effect on stabilizing the performance. Furthermore, due to the synergy of the upper layer organic resin and the film composed of fine silica, not only the corrosion resistance and coating adhesion including the processed part, but also the press appearance, the anti-fingerprint property, the anti-condensation resistance, etc. Various performances with respect to quality can be improved. By separating the functions by the two-layer processing, the above-mentioned problems of the processing agent life and performance deterioration can be easily solved. Furthermore, development to higher quality can be expected.

Hereinafter, embodiments of the present invention will be described in detail. The base metal plate applicable in the present invention includes iron, iron-based alloy, aluminum, aluminum-based alloy, copper, and copper-based alloy. A plated metal plate optionally plated on a metal plate can also be used.As the plated metal plate, a zinc-plated metal plate, a zinc-nickel plated metal plate, a zinc-iron plated metal plate, a zinc-chrome plated metal plate, Zinc-based electroplating, hot-dip plating, vapor-deposited steel sheet, such as zinc-aluminum-plated metal sheet, zinc-titanium-plated metal sheet, zinc-magnesium-plated metal sheet, and zinc-manganese-plated metal sheet
Aluminum or aluminum alloy-plated metal plate, lead or lead alloy-plated metal plate, tin or tin alloy-plated metal plate, and a small amount of different metal elements or impurities such as cobalt, molybdenum, tungsten, nickel, titanium, chromium , Manganese, iron, magnesium, lead, antimony, tin, copper, cadmium, arsenic, etc., and / or silica, alumina, titania, etc. dispersed therein. Further, the present invention is also applicable to a multi-layer plating in which the above plating is combined with another type of plating, for example, iron plating, iron-phosphorus plating, or the like. The plating method is not particularly limited, and may be any of known methods such as an electroplating method, a hot-dip plating method, a vapor deposition plating method, a dispersion plating method, and a vacuum plating method. In addition, these metal plates can be subjected to ordinary treatment such as hot water washing and alkali degreasing before the base treatment.

The undercoating treatment used in the present invention is characterized in that a chemical solution containing an aqueous resin, a silane coupling agent and a phosphoric acid component is applied and dried. As the aqueous resin used for the base treatment, in addition to a water-soluble resin, a resin that is originally water-insoluble but can be in a finely dispersed state in water such as an emulsion or a suspension (a water-dispersible resin). Say including. The resin that can be used as such an aqueous resin is not particularly limited, but is a polyolefin resin, an acrylic olefin resin, a polyurethane resin, an acrylic resin, a polycarbonate resin, an epoxy resin, a polyester resin, an alkyd resin. , Phenolic resins, other heat-curable resins, and the like, and more preferably crosslinkable. The organic resin may be used as a mixture of two or more or a copolymer. Among them, especially wettability with the upper layer film,
In consideration of the adhesion, it is desirable to select a resin having a high acid value and / or hydroxyl value.

Examples of the silane coupling agent used for the base treatment include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-aminoethyl)
Aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ-
(2-aminoethyl) aminopropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane,
γ-methacryloxypropylmethyldiethoxysilane,
N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (N-vinyl Benzylaminoethyl) -γ-aminopropyltriethoxysilane,
N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane Silane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane,
γ-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane,
Vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltriethoxysilane, γ-
Chloropropylmethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ
-Anilinopropyltriethoxysilane, γ-anilinopropylmethyldiethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl ] Ammonium chloride, octadecyldimethyl [3- (methyldimethoxysilyl) propyl] ammonium chloride, octadecyldimethyl [3- (triethoxysilyl) propyl] ammonium chloride, octadecyldimethyl [3- (methyldiethoxysilyl)
Propyl] ammonium chloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and the like.Examples thereof include γ-glycidoxypropyltrimethoxysilane having a glycidyl ether group, and γ-glycidoxypropyltriethoxysilane. When used, the adhesion to the upper layer film is further improved.

The content of the silane coupling agent is 0.1 to 300 parts by weight based on 100 parts by weight of the aqueous resin in terms of solid content.
It is preferably 0 parts by weight. If the amount is less than 0.1 part by weight, sufficient adhesion to the underlying metal and the upper layer film cannot be obtained, and the corrosion resistance is not sufficient. If the amount exceeds 3,000 parts by weight, workability and corrosion resistance, particularly the corrosion resistance of the processed portion may be deteriorated, and the resin may be gelled in the state of the treatment agent to cause problems.

As the phosphoric acid component used for the base treatment,
Orthophosphoric acid (H ₃ PO _4), hypophosphorous acid (H ₃ PO _2), phosphorous acid (H ₃ PO _3), pyrophosphoric acid _{(H 4 P 2 O 7)} , tripolyphosphate (H ₅ P ₃ O ₁₀ ) and the chemical formula is H _{X + 2} P _X O
All acids of _{3X + 1} (where X is an integer of 3 or more) condensed phosphoric acids and salts thereof are included. Particularly, orthophosphate, phosphite, hypophosphite, and pyrophosphate are preferable because they are economical.

Phosphoric acid component (as P-containing anion component)
Is preferably 0.01 to 100 parts by weight based on 100 parts by weight of the aqueous resin in terms of solid content.
If the amount is less than 0.01 parts by weight, sufficient adhesion to the underlying metal and the upper layer film cannot be obtained, and the corrosion resistance is not sufficient. 100
If the amount is more than the weight part, the workability and the corrosion resistance, particularly the corrosion resistance of the processed part may be degraded, or the resin may be gelled in the state of the treatment agent to cause a problem.

The undercoating in the present invention may include finely divided silica. When the surface treatment contains fine silica,
The adhesion to the upper layer film and the corrosion resistance are improved. As the finely divided silica used for the base treatment, any of spherical, linear, or beaded silica in which spherical silica having a branch is bonded may be used. In the case of spherical silica, the particle diameter is 5 to 5
0 nm, for linear silica, 5-50 nm in diameter and length /
In the case of chemically bonded ones having a thickness ratio of 1 to 5 or branched beaded silica, the ratio of [length of conjugate / average particle size of spherical silica] is 4 or more and at least one location. Those having a branch are preferred. If the primary particle size exceeds 50 nm, it is difficult to form a dense film, and the adhesion to the upper film and the corrosion resistance may deteriorate. As the type of the fine silica, water-dispersible silica, fine powder silica, and the like can be used. The water-dispersible silica is a generic term for silica having such properties that it can maintain a water-dispersed state when dispersed in water because of having a fine particle size, and semipermanently does not have sedimentation. As water-dispersible silica,
From the viewpoint of corrosion resistance, those containing less impurities such as sodium are preferable. For example, "Snowtex N", "Snowtex C", "Snowtex UP", "Snowtex PS" (all manufactured by Nissan Chemical Industries), "Adelite AT"
Commercially available silica gels such as "-20Q" and "Adelite AT-20N" (all manufactured by Asahi Denka Kogyo) can be used. Silica fine powder is generally called dry silica, and fine silica such as "Aerosil # 300" (manufactured by Nippon Aerosil) can be used. The fine silica may be appropriately selected according to the required performance.

The content of the finely divided silica is preferably 1 to 2,000 parts by weight based on 100 parts by weight of the aqueous resin in terms of solid content. If the amount is less than 1 part by weight, the effect of addition is small. If the amount exceeds 2,000 parts by weight, the effect of improving corrosion resistance is saturated, which is uneconomical. In addition, the treated film becomes too hard, the film is cracked, etc. Adhesion with the film may be reduced.

Further, the underlayer treatment in the present invention may include an etching fluoride. When the base treatment contains an etching fluoride, the adhesion to the upper layer film is improved and stabilized. In the present invention, as the etching fluoride, zinc fluoride tetrahydrate, zinc hexafluorosilicate hexahydrate, zircon hydrofluoric acid, titanium hydrofluoric acid, hydrofluorosilicic acid, and the like can be used. .
The content of the etchable fluoride is preferably 0.1 to 1000 parts by weight based on 100 parts by weight of the aqueous resin in terms of solid content. If it is less than 0.1 part by weight, the effect of addition is small, and if it exceeds 1000 parts by weight, the effect of improving corrosion resistance is saturated and uneconomical.

In order to form an undercoating layer on a metal plate, the above-mentioned undercoating agent is applied to the metal plate, heated and dried. The adhesion amount of these undercoat layers is 5 to 500 mg in terms of solid content.
/ M ² . If the amount is less than 5 mg / m ² , a sufficient effect cannot be obtained, and the adhesion to the underlying metal or the upper layer film and the corrosion resistance may decrease. Even if it exceeds 500 mg / m ² , the adhesiveness to the underlying metal and the upper layer film may be rather reduced.

As a coating method for forming the undercoating layer, any method such as spraying, curtain, flow coater, roll coater, bar coater, brush coating, dipping, and air knife drawing may be used.
The ultimate heating temperature is preferably 50 to 250 ° C.
If the temperature is lower than 50 ° C., sufficient film-forming properties cannot be obtained, so that the adhesion to the underlying metal or the upper layer film and the corrosion resistance are reduced, and appearance unevenness occurs. On the other hand, if the temperature exceeds 250 ° C., the alkyl portion of the organic resin or the silane coupling agent undergoes modification such as thermal decomposition, or the treated film becomes too hard, and the adhesion and corrosion resistance with the base metal and the upper layer film become poor. descend. 70-160 ° C is more preferred.

Although there is no particular limitation on the drying equipment, a method using hot air blowing, a method using indirect heating with a heater, a method using infrared rays, a method using induction heating, and a method using these in combination can be adopted. Further, depending on the type of the aqueous resin used, the resin can be cured by energy rays such as ultraviolet rays and electron beams.

The upper layer film used in the present invention is characterized in that a chemical solution containing an organic resin and fine silica particles is applied to the upper layer of a metal plate which has been subjected to base treatment, and is baked and dried. The organic resin used for the upper layer coating may be any form of an aqueous resin, a solvent resin, a powder resin, or a solventless resin. The term “aqueous resin” used herein includes not only water-soluble resins but also resins that are inherently water-insoluble but can be finely dispersed in water such as emulsions and suspensions (water-dispersible resins). . The resin that can be used as the organic resin is not particularly limited, but includes a polyolefin resin, an acrylic olefin resin, a polyurethane resin, an acrylic resin, a polycarbonate resin, an epoxy resin, a polyester resin, an alkyd resin, and a phenol resin. Resins and other heat-curable resins can be exemplified, and it is more preferable that the resin be crosslinkable. Organic resin is 2
Mixtures of more than one kind or copolymerization may be used. If necessary, a crosslinking agent such as various melamine resins and amino resins may be added. Among these, when considering both performance and cost, it is preferable to use an acrylic olefin resin or an acrylic resin. When strict deep drawing is required, it is preferable to use a urethane resin having both hardness and elongation.

As fine silica used for the upper layer coating,
Any of spherical, linear, or beaded silica having branched spherical silica bonded thereto may be used. In the case of spherical silica, the particle diameter is 5 to 50 nm, in the case of linear silica,
In the case of a beaded silica having a diameter of 5 to 50 nm and a length / thickness ratio of 1 to 5 chemically, or a branched beaded silica, the ratio of [length of conjugate / average particle size of spherical silica] is Those having 4 or more and one or more branches are preferred. If the primary particle size exceeds 50 nm, it is difficult to form a dense film, and the corrosion resistance may deteriorate. As the type of the fine silica, water-dispersible silica, fine powder silica, organic solvent-dispersible silica, and the like can be used. The water-dispersible silica is a generic term for silica having such properties that it can maintain a water-dispersed state when dispersed in water because of having a fine particle size, and semipermanently does not have sedimentation. As the water-dispersible silica, those having few impurities such as sodium are preferable from the viewpoint of corrosion resistance. For example,
"Snowtex N", "Snowtex C", "Snowtex UP", "Snowtex PS" (manufactured by Nissan Chemical Industries), "Adelight AT-20Q", "Adelight AT-20N" (manufactured by Asahi Denka Kogyo) ) Can be used. The silica fine powder is generally called dry silica, and fine silica such as “Aerosil # 300” (manufactured by Nippon Aerosil) can be used. The organic solvent dispersible silica is a so-called organosilica sol, for example, US Pat. No. 2,285,4.
No. 49 dispersed in an organic solvent by the production method described in JP-A No. 49-49. That is, a silica sol obtained by substituting water in an aqueous dispersion of colloidal silica sol with an organic solvent and using an alcohol such as methanol, isopropanol, or butyl cellosolve as a dispersion medium is particularly useful. The fine silica may be appropriately selected depending on the dispersion form of the resin in the treatment agent and the required performance.

The upper layer film in the present invention can contain a lubricant. The type of the lubricant may be either an organic lubricant or an inorganic lubricant, but an organic lubricant is preferable in consideration of the lubricity after the film is formed. As the organic lubricant, a polyolefin resin fine powder having an average particle diameter of 20 μm or less is effective. Any material may be used as long as it is made of a polymer of an olefinic hydrocarbon such as polyethylene, polypropylene, and polybutene, or a combination thereof. The polyolefin resin fine powder preferably has a weight average molecular weight of 500 or more from the viewpoint of quality. If the weight average molecular weight is less than 500, the surface of the resin film becomes sticky, which may cause blocking during storage of the coil, which is not preferred. In addition to the fine powder of the polyolefin resin, fine powders of a fluorine resin, for example, a polytetrafluoroethylene resin, a polyhexafluoride polypropylene resin, a polyvinylidene fluoride resin, or the like, may be used. Powders may be used in combination. As the inorganic lubricant, graphite, molybdenum disulfide or the like may be used.

The content of the lubricant is preferably 1 to 30 parts by weight based on 100 parts by weight of the aqueous resin in terms of solid content. If the amount is less than 1 part by weight, the effect of addition is small, and
Exceeding the weight part is not preferred because the paint adhesion may be deteriorated. More preferably, it is in the range of 2 to 15 parts by weight. Further, a surfactant, a rust inhibitor, an antifoaming agent and the like may be added to these upper layer coatings as necessary.

The range of the amount of adhesion of the upper layer coating is 0.1 to 5 g / m ^{2 in} terms of dry weight. More preferably, it is 0.3 to 3.0 g / m ² . 0.1 g / m ² adhesion amount
If it is less than 5, the corrosion resistance is inferior, and if it exceeds 5.0 g / m ² , weldability becomes difficult, which is not preferable. As an application method for forming these upper layers, any method such as spraying, curtain, flow coater, roll coater, bar coater, brush coating, dipping, and air knife drawing may be used.

The ultimate baking temperature is 80 to 250 ° C.
It is desirable that If the temperature is lower than 80 ° C., the corrosion resistance is reduced because the water in the paint is difficult to completely evaporate. If the temperature is higher than 250 ° C., the alkyl portion of the organic resin undergoes denaturation such as thermal decomposition or the film hardens too much. It is not preferable because corrosion resistance and workability are reduced. 70-160 ° C is more preferred.

The drying equipment is not particularly limited, but a method using hot air, a method using indirect heating with a heater, a method using infrared rays, a method using induction heating, and a method using these in combination can be adopted. In addition, depending on the type of the organic resin used, the resin can be cured by energy rays such as ultraviolet rays and electron beams.

[0036]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (1) Kind of metal plate The metal plate shown in Table 1 was used.

[0037]

[Table 1]

(2) Types of base treatment chemicals Table 2 shows a list of base treatment chemicals used in the examples.

[0039]

[Table 2]

(3) Adjustment of the base treatment agent The aqueous resin, silane coupling agent, phosphoric acid component, fine silica, and etching fluoride shown in Table 1 were blended in the ratios shown in Tables 5, 6, and 9, and the base treatment agent was prepared. Was adjusted. (4) Method of applying / drying the base treatment agent Roll the aqueous metal-organic composite paint prepared in (2) on the plated metal plate shown in (1) so that the dry weight becomes the value shown in Tables 5, 6 and 9 Apply with a coater, and in a hot air oven, Table 5,
Samples for evaluation were prepared by baking and drying at the plate temperatures shown in 6 and 9. Table 5 shows the adhesion amount of the undercoating film.
6 and 9. (5) Types of upper layer coating chemicals Table 3 shows a list of upper layer coating chemicals used in the examples.

[0041]

[Table 3]

(6) Preparation of upper layer coating agent The organic resin, fine silica and lubricant shown in Table 3 were used in Tables 7, 8,
The mixture was blended at the ratio shown in Fig. 10 to prepare an upper layer coating agent. (7) Coating and drying method for base treatment chemicals
Table 7, 8, 1
It was applied with a roll coater so as to have a value shown as 0, and was baked and dried in a hot-air oven at the plate temperatures shown in Tables 7, 8, and 10 to produce a sample for evaluation. Tables 7, 8, and 10 show the amount of the upper layer film attached. (8) Performance evaluation items 1) Adhesion of upper layer film For the evaluation sample manufactured in (7), JISK5
The extruded upper layer film was extruded by 7 mm using an Erichsen tester specified in No. 400 so that a convex portion was formed, and an adhesive tape (Nichiban Co., Ltd .: Cellotape) was attached to the extruded portion. The adhesive tape was immediately pulled obliquely at an angle of 45 °, and the appearance of the extruded portion was visually judged. When it was difficult to visually evaluate the adhesion, the dyeing was performed with a 3% acetone solution of methyl violet, and the coating was determined to be present on the dyed portion and the coating was not present on the unstained portion, and the adhesion was determined. The criteria were as follows, and ◎ and ○ were judged to be good.

◎: No peeling of the coating ○: Peeling of less than 20% area △: Peeling of less than 50% area ×: Peeling of more than 50% area 2) Flat plate corrosion resistance JISZ237 as a flat plate (sealing the end face and back face of the steel sheet as cut)
The salt spray test described in 1 was performed, and the white rust occurrence rate after 72 hours was measured. In the following evaluations, ◎ and ○ were judged to be good.

◎: No white rust generated ○: White rust generation rate less than 10% △: White rust generation rate 10% or more, less than 50% ×: White rust generation rate 50% or more 3) Corrosion resistance in processed part (7) JISK54 about the sample for evaluation
The extruded upper layer film is extruded by 6 mm with an Erichsen tester specified in No. 00 (the end face and the back face of the steel sheet extruded by 6 mm with the Erichsen tester are sealed) and described in JISZ2371. A salt spray test was performed to measure the white rust generation rate in the extruded portion after 48 hours. In the following evaluations, ◎ and ○ were judged to be good.

◎: No white rust generated ○: White rust generation rate less than 5% △: White rust generation rate 5% or more and less than 20% ×: White rust generation rate 20% or more 4) Paint adhesion (7) Using a bar coater, a melamine alkyd resin paint (Amilac # 1000, manufactured by Kansai Paint Co., Ltd.) was further applied to the evaluation sample thus obtained.
It was applied to a thickness of μm and baked at a furnace temperature of 130 ° C. for 20 minutes. Next, after being left overnight, those immersed in boiling water for 30 minutes and those not immersed were subjected to a 7 mm Erichsen process, and an adhesive tape (Nichiban Co., Ltd .: Cellotape) was attached to the Eriksen-processed portion of the test piece. Was. The adhesive tape was quickly pulled obliquely at an angle of 45 °, and the appearance of the Erichsen processed portion was visually evaluated. In the following evaluations, ◎ and ○ were judged to be good.

: No peeling ○: Peeling area ratio less than 5% △: Peeling area ratio 5% or more and less than 50% ×: Peeling area ratio 50% or more 5) Continuous weldability Table 4 shows the samples prepared in (7). A continuous spot welding test was performed under the conditions shown in (1), and the number of spots at which a nugget diameter of 3 mmφ or more could be formed stably was determined.

[0047]

[Table 4]

In the following evaluations, ◎ and ○ were judged to be good. ◎: Number of hit points 5000 or more ○: Number of hit points 2500 or more and less than 5000 △: Number of hit points 1000 or more and less than 2500 ×: Number of hit points less than 1000 6) Press galling resistance The sample prepared in (7) was subjected to a square cylinder crank press test. . The conditions of the rectangular cylinder crank press test were such that a sample (0.8 × 220 × 180 mm) was formed into a 65 × 115 mm and a height of 30 mm with a wrinkle holding pressure of 4 tons, and the sliding surface after the molding was visually evaluated. In the following evaluations, ◎ and ○ were judged to be good.

◎: no blackening ○: less than 50% of the sliding part is blackened and has sliding flaws △: 50% or more of the sliding part is blackened and has sliding flaws ×: base metal 7) Fingerprint resistance A fingerprint resistance test was performed on the sample prepared in (7). In the fingerprint resistance test, a real finger was pressed against the sample for 3 seconds, and the degree of conspicuousness of the fingerprint was visually evaluated. In the following evaluation ◎
And ○ were determined to be good.

◎: Fingerprint traces are not recognized ○: Fingerprint traces are observable by good observation △: Fingerprint traces are slightly noticeable ×: Fingerprint traces are noticeable The above evaluation results are shown in Tables 5 to 10. According to the technology of the present invention, it is possible to obtain a welded surface-treated metal plate which is excellent in various performances such as corrosion resistance, paint adhesion, press galling resistance, fingerprint resistance and the like.

[0051]

[Table 5]

[0052]

[Table 6]

[0053]

[Table 7]

[0054]

[Table 8]

[0055]

[Table 9]

[0056]

[Table 10]

[0057]

According to the present invention, the treated film contains no harmful chromium such as hexavalent chromium and has not only corrosion resistance and paint adhesion, but also galling resistance at the time of pressing, fingerprint resistance, and unevenness of dew condensation. For example, it is possible to provide a weldable surface-treated metal sheet excellent in various performances with respect to the surface appearance quality of a steel sheet, and is particularly suitable as a material for automobiles, home appliances, and building materials. Therefore, the present invention can be said to be an invention having extremely high industrial value.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C10M 103/02 C10M 103/02 Z 103/06 103/06 C 107/02 107/02 107/38 107 / 38 125/26 125/26 143/00 143/00 145/14 145/14 145/20 145/20 145/22 145/22 149/18 149/18 169/04 169/04 173/02 173/02 C23C 22/36 C23C 22/36 28/00 28/00 C // C10N 10:12 C10N 10:12 20:06 20:06 Z 30:06 30:06 30:12 30:12 50:02 50:02 50 : 08 50:08 80:00 80:00 (72) Inventor Yujiro Miyauchi 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation Kimitsu Works (72) Inventor Akira Takahashi 1 Kimitsu, Kimitsu City, Chiba Prefecture New F Term in Kimitsu Works of Nippon Steel Corporation (Reference) 4D075 CA13 CA33 CA39 CA48 DA23 DB02 DB05 DB06 DB07 DC01 DC11 DC18 EA06 EA10 EA13 EA19 EB13 EB22 EB32 EB33 EB35 EB36 EB38 EB52 EB55 EB56 EB57 EC03 EC22 EC24 EC45 EC53 EC54 4F100 AA04B AA20C AB01A AH06B AK01B AK01C AK24 AK33 AK41 AK51 AK53 BA01A BA02 BA07 BA10C EJ65B EJ67B GB07 GB32 JB02 JB05B JK20 YY00B YY00C 4H104 AA04A AA19A AA22C CA01A CA01C CA02A CA03A CA04A CB08C CB12C CB13C CD01A CE13C EA08C FA06 LA03 LA06 PA34 QA08 QA12 4K026 AA02 AA07 AA12 AA13 AA22 BA01 BA03 BA12 BB04 BB06 BB08 BB09 BB10 CA16 CA23 CA28 CA37 CA39 CA41 DA15 DA16 EB08 4K044 AA02 AB02 BA10 BA17 BA20 BA21 BB04 CA01 BC02 BC04 BC05 BC05

Claims (6)

[Claims] A coating layer containing an aqueous resin, a silane coupling agent, and a phosphoric acid component is provided as a base treatment layer.
0.1 to 5 parts by weight of the upper film containing 0 parts by weight of fine silica.
g / m < ² >, The surface-treated metal plate characterized by the above-mentioned. 2. The undercoating layer contains a silane coupling agent in an amount of 0.1 part by weight based on 100 parts by weight of an aqueous resin as a solid content.
2. The surface-treated metal sheet according to claim 1, comprising 1 to 3000 parts by weight and 0.01 to 100 parts by weight of a phosphoric acid component. 3. The method according to claim 1, wherein the undercoating layer is formed of, based on 100 parts by weight of the aqueous resin, 1 to 2000 parts by weight of fine-particle silica and 0.1 to 1000 parts by weight of an etching fluoride in terms of solid content. The surface-treated metal sheet according to claim 1, further comprising at least one species. 4. The surface-treated metal sheet according to claim 1, wherein the silane coupling agent contained in the undercoating layer has a glycidyl ether group. 5. The method according to claim 1, wherein an amount of the base treatment layer is in terms of solid content.
5 to 500 mg / m ^Two2. The method according to claim 1, wherein
5. The surface-treated metal plate according to any one of items 4 to 4. 6. The method according to claim 1, wherein the upper layer film further contains 1 to 30 parts by weight of a lubricant based on 100 parts by weight of the organic resin in terms of solid content. A surface-treated metal plate according to item 1.