JP2003166079A - Precoated metal sheet superior in press formability, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precoated metal sheet superior in press formability, and a manufacturing method therefor. <P>SOLUTION: The precoated metal sheet superior in press formability has a chemical conversion coating layer on one side or both sides, which contains, at least either of tannin or tannic acid, a silane coupling agent, and fine silica powders, altogether as solid contents, and further has a painted layer thereon, which contains an aluminum phosphate-based pigment of 1-140 pts.mass to a resin solid content of 100 pts.mass. The manufacturing method is also disclosed. The chemical conversion coating layer preferably further contains a polyester resin. The painted layer preferably further contains a rust preventive pigment. In addition, the aluminum phosphate-based pigment optimally includes aluminum dihydrogentripolyphosphate. The rust preventive pigment optimally includes calcium ion-exchangeable silica. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface-treated metal material having excellent press formability and corrosion resistance, which can be used for home appliances, building materials, civil engineering, machinery, automobiles, furniture, containers, etc. It is said that there are especially environmental problems 6
It is characterized by exhibiting coating film adhesion and rust preventive effect during press molding without using valent chromium.

[0002]

2. Description of the Related Art For home electric appliances, building materials, automobiles, etc., pre-coated metal coated with a colored coating film has come to be used in place of the conventional post-painted products that have been painted after processing. . This metal plate is obtained by coating a metal plate that has been pretreated for metal with a coating material, and is generally used after being coated with the coating material and then cut and press-molded. Therefore, the corrosion resistance of the cut end surface where the coating film is not coated and the peeling of the coating film at the time of pressing have been problems of the precoated metal plate, but the chromate treatment is performed as a pretreatment for metal, and By containing a hexavalent chromium-based rust preventive pigment in the coating film, these problems are solved,
It is now used for general purposes.

However, due to the environmental problems of hexavalent chromium which may be eluted from a coating film containing a chromate treatment and a hexavalent chromium anticorrosive pigment, recently, a non-chromate chemical conversion treatment containing no hexavalent chromium and a non-chromate conversion treatment The demand for chromate paint films is increasing. JP 2001-8
Japanese Patent No. 9868 discloses a technique for providing a precoated metal sheet having excellent workability adhesion and corrosion resistance by using a chemical conversion treatment containing tannin and tannic acid, a silane coupling agent, and finely divided silica at the same time instead of the chromate treatment. ing. On the other hand, in Japanese Unexamined Patent Publication (Kokai) No. 9-12931, instead of the hexavalent chromium type anticorrosive pigment, a phosphoric acid type anticorrosive pigment and an ion exchange silica type anticorrosive pigment are used in combination with a polyester type and an epoxy type paint to cut end faces A technique for providing a precoated metal plate having excellent corrosion resistance is disclosed.

The chemical conversion treatment technology disclosed in Japanese Unexamined Patent Publication No. 2001-89868 is excellent in the adhesion of the processed portion in the Erichsen test and the T-folding test, but when the press formability represented by deep drawing is performed. In comparison with the chromate-treated pre-coated metal plate, the coating film has a drawback that it is easily bitten by the press die and peeled off. On the other hand, in the technique disclosed in Japanese Patent Laid-Open No. 9-12931,
Since zinc phosphate treatment is used for the chemical conversion treatment, the adhesion of the coating film in the processed part is insufficient compared to the chromate-treated pre-coated metal sheet with this technology. Therefore, the coating film had a defect that it was easily peeled off.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems in the prior art and provides a precoated metal sheet having excellent corrosion resistance even without containing hexavalent chromium, and further excellent in press formability, and a method for producing the same. The task is to provide.

[0006]

The inventors of the present invention have formed a chemical conversion treatment coating layer containing at least one of tannin and tannic acid, a silane coupling agent, and fine silica particles at the same time. It has been found that by forming a coating layer containing an aluminum-based pigment, a composite coating having not only corrosion resistance but also excellent press moldability can be obtained. The present invention has been completed based on such findings, and the gist thereof is as follows. (1) On one or both sides of a metal plate, as a solid content, at least one of tannin and tannic acid, a silane coupling agent, and a chemical conversion treatment coating layer containing fine silica particles at the same time, and a resin solid content thereon. A precoated metal sheet having excellent press formability, which further comprises a coating layer containing 1 to 140 parts by mass of an aluminum phosphate pigment with respect to 100 parts by mass. (2) The precoated metal sheet having excellent press formability according to (1), wherein the chemical conversion coating layer further contains a polyester resin as a solid content. (3) The aluminum phosphate-based pigment contained in the coating layer is
The precoated metal sheet having excellent press formability according to (1) or (2) above, which is aluminum dihydrogen tripolyphosphate. (4) The coating layer further contains a rust preventive pigment, and the total content of the rust preventive pigment and the aluminum phosphate pigment is 10 resin solids.
140 parts by mass or less with respect to 0 parts by mass, The precoated metal plate having excellent press formability according to any one of (1) to (3) above. (5) The precoated metal sheet having excellent press formability according to (4), wherein the rust preventive pigment contained in the coating layer is calcium ion-exchangeable silica. (6) The precoated metal plate having excellent press formability according to any one of (1) to (5), wherein the metal plate is a metal plate having a plating layer on one side or both sides. (7) A treatment liquid containing at least one of tannin and tannic acid, a silane coupling agent and fine silica particles is applied to one or both surfaces of a metal plate at the same time and dried to form a chemical conversion treatment film layer, and further a resin. Solid content 10
A method for producing a precoated metal sheet having excellent press formability, which comprises applying a coating material containing 1 to 140 parts by mass of an aluminum phosphate pigment to 0 part by mass and drying and curing the paint. (8) The method for producing a precoated metal sheet having excellent press formability as described in (7) above, wherein the treatment liquid further contains a polyester resin. (9) The paint further contains a rust preventive pigment, and the total content of the rust preventive pigment and the aluminum phosphate pigment is 100 resin solids.
The method for producing a precoated metal sheet having excellent press formability according to (7) or (8) above, which is 140 parts by mass or less based on parts by mass.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a chemical conversion method in which one surface or both surfaces of a metal plate or a plated metal plate contains at least one of tannin and tannic acid as a solid content, a silane coupling agent, and fine silica particles at the same time. Treatment A treatment film layer is formed, and an aluminum phosphate pigment is further applied on top of it.
It is achieved by forming a coating layer containing ˜140 parts by mass. It is more preferable that the aluminum phosphate-based pigment is aluminum dihydrogen tripolyphosphate because the coating film is less likely to be galled during press molding. Further, when the chemical conversion treatment film layer applied to the precoated metal plate of the present invention further contains a polyester resin as a solid content, the coating film adhesion is improved, and the coating film is more resistant to galling during press molding, which is more preferable.

It is preferable to add a rust preventive pigment to the coating layer formed on the precoated metal sheet of the present invention in addition to the aluminum phosphate pigment, because the corrosion resistance of the precoated metal sheet is improved. The addition amount of these pigments is preferably such that the total content of the aluminum phosphate pigment and the rust preventive pigment is 140 parts by mass or less with respect to 100 parts by mass of the resin solid content. Furthermore, it is preferable that the rust preventive pigment is calcium ion-exchangeable silica because the corrosion resistance is further improved.

The chemical conversion treatment film layer formed on the precoated metal plate of the present invention contains at least one of tannin and tannic acid, a silane coupling agent, and fine silica simultaneously, or a polyester resin in addition to the treatment liquid. It is more preferable that the pretreatment metal plate of the present invention can be produced more efficiently if the treatment liquid is applied and dried. Furthermore, the coating layer formed on the precoated metal plate of the present invention is formed by applying a coating material containing an aluminum phosphate pigment, or an aluminum phosphate pigment and an anticorrosion pigment at the same time and drying and curing it. The precoated metal plate of the present invention can be manufactured more efficiently, and is therefore more preferable.

As a result of various studies on the non-chromate pre-coated metal plate in which the coating film is difficult to be galvanized by the press die when press-molded, the present inventors have found that the metal plate or the plated metal plate has tannin and / or tannin. By forming a chemical conversion treatment coating layer containing tannic acid, a silane coupling agent and finely divided silica at the same time, and further forming a coating layer containing an aluminum phosphate pigment on it, it is possible to scratch the press die during press molding. It was found that the phenomenon in which the coating film peels off due to this is dramatically improved. The phenomenon in which the coating film is galled on the press die during press molding and peels off is due to the shearing force applied to the coating film of the precoated metal plate under a high load by the press die and acting on the coating film at this time. Conceivable.
Therefore, the following two methods can be considered as means for improving this problem. The first is to increase the adhesion between the coating and the metal. Secondly,
It is to make it difficult for the shearing force acting on the coating film to be transmitted to the interface between the coating film and the original metal plate, which is the coating film peeling surface. The details of the reason why the coating film is difficult to be galled in the press mold when the precoated metal sheet of the present invention is press-formed are not known.
Adhesion of tannin and / or tannic acid with excellent adhesion, chemical conversion treatment film layer containing silane coupling agent and fine silica particles at the same time, and coating layer containing aluminum phosphate pigment, synergistic effect It is presumed that the shear stress generated in the coating film during press molding is hard to be transmitted to the interface between the coating film and the metal plate due to the unique mechanical properties of the aluminum phosphate pigment.

The metal plate used in the precoated metal plate of the present invention is a cold rolled steel plate, a hot rolled steel plate, a hot dip galvanized steel plate, an electrogalvanized steel plate, a hot dip galvanized steel plate, an aluminized steel plate, an aluminium-zinc alloyed plating plate. Generally known metal plates and plated plates such as a steel plate, an aluminum-magnesium-zinc plated steel plate, an aluminum-magnesium-silicon-zinc plated steel plate, a stainless steel plate, and an aluminum plate can be applied. These metal plates may be subjected to usual treatments such as washing with hot water and alkaline degreasing before the chemical conversion treatment before use.

The chemical conversion treatment coating layer applied to the precoated metal plate of the present invention is characterized by containing tannin and / or tannic acid, a silane coupling agent, and fine silica particles.

The tannin and tannic acid used may be hydrolyzable tannins or condensed tannins, or may be those in which some of these have been decomposed. Tannins and tannic acids include, but are not limited to, hamameta tannins, quintet tannins, gallic tannins, tannins of myrobalans, tannins of dividibi, tannins of agarovilla, tannins of baronia, and catechins, but "tannic acid: AL".
When (Fuji Chemical Industry Co., Ltd.) is used, the processing adhesion of the coating film is particularly improved. The addition amount of at least one of tannin and tannic acid is not particularly specified, but the content in the chemical conversion treatment solution applied to the metal plate to form the tannin or tannic acid is 2
It is more preferable that it is ˜80 g / l. If the addition amount of at least one of tannin and tannic acid is less than 2 g / l, the rust preventive effect and coating film adhesion may not be ensured,
On the other hand, if it exceeds 80 g / l, the anticorrosion effect and the coating film adhesion may be rather deteriorated, or it may not be dissolved in the aqueous solution.

The silane coupling agent used is, for example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyl. Triethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, γ- (2
-Aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
γ-methacryloxypropylmethyldimethoxysilane,
γ-methacryloxypropyltriethoxysilane, γ-
Methacryloxypropyl methyldiethoxysilane, N-
β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (N-vinylbenzylamino) Ethyl) -γ-aminopropyltriethoxysilane, N-
β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-
Mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloro Propyltriethoxysilane, 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, γ-chloropropylmethyldimethoxysilane, γ -Mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane and the like can be mentioned, but γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane having a glycidyl ether group. When used, the processing adhesion of the coating film is particularly improved. Furthermore, when a triethoxy type silane coupling agent is used, the storage stability of the undercoat material can be improved. It is considered that this is because triethoxysilane is relatively stable in an aqueous solution and the polymerization rate is slow.

The amount of the silane coupling agent added is not particularly limited, but the content in the chemical conversion treatment liquid applied to the metal plate to form the chemical conversion coating layer is 2 to 80 g /
More preferably, it is 1. If it is less than 2 g / l, sufficient coating film adhesion may not be obtained during processing, and corrosion resistance may be insufficient. If it exceeds 80 g / l, the coating film adhesion may be rather deteriorated.

The fine-grained silica used in the present invention is a generic term for silica which has a fine particle diameter and can stably maintain a water-dispersed state when dispersed in water. Examples of the fine silica particles include “Snowtex N”, “Snowtex C”, and “Snowtex U”.
Commercially available silica gel such as "P", "Snowtex PS" (all manufactured by Nissan Chemical Industry), "Adelite AT-20Q" (manufactured by Asahi Denka Kogyo), or powdered silica such as Aerosil # 300 (manufactured by Nippon Aerosil). Can be used. The fine silica particles may be appropriately selected according to the required performance. As the fine silica, "Snowtex C", which can be stably dispersed even at a pH of 4 or more, can be used to improve the storage stability of the base treatment agent. It is considered that this is because the pH of the chemical solution can be adjusted to 4 or more, and thus the reaction of the silane coupling agent having high reactivity at low pH can be suppressed.

The amount of finely divided silica added is not particularly limited, but the content in the chemical conversion treatment liquid applied to the metal plate to form the chemical conversion coating layer is preferably 1 to 40 g / l. . If it is less than 1 g / l, the coating adhesion of the coating film may be poor, and if it exceeds 40 g / l, the effects of processing adhesion and corrosion resistance are saturated, which is uneconomical.

It is more preferable that the chemical conversion treatment film layer further contains a polyester resin as a solid content because the processing adhesion is further improved. The content of the polyester resin is not particularly limited, but when the content in the chemical conversion treatment liquid applied to the metal plate to form the chemical conversion treatment coating layer is 1 to 60 g / l, the processing adhesion is further improved. Is improved. If it is less than 1 g / l, the effect of resin addition is not observed, and 6
If it exceeds 0 g / l, the coating film adhesion may rather deteriorate. As the polyester resin, for example,
"Finetex ES-650", "Finetex ES-611", "Finetex ES-67"
0 "," Finetex ES-675 "(all manufactured by Dainippon Ink and Chemicals)," Vironard MD-120 "
0 "," Baironard MD-1220 "," Baironard MD-1250 "," Baironard MD-110 "
0 ”,“ Baironard MD-1330 ”,“ Baironard MD-1930 ”(all manufactured by Toyobo) and the like can be used.

An acid, an alkali or the like may be added to the chemical conversion treatment liquid applied to form the chemical conversion treatment film layer of the present invention for pH adjustment within the range where the performance is not impaired.

To form a chemical conversion treatment layer on a metal plate,
It is preferable to apply the above-mentioned chemical conversion treatment agent to a metal plate and bake and dry it, because the production efficiency is further improved. For the baking temperature,
50-250 degreeC is good. If the temperature is lower than 50 ° C., the evaporation rate of water is slow and a sufficient film-forming property cannot be obtained. On the other hand, when the temperature exceeds 250 ° C., tannin, tannic acid, which is an organic substance, and the alkyl portion of the silane coupling agent are modified by thermal decomposition and the like, and the adhesion and corrosion resistance are deteriorated. 70-160 degreeC is more preferable. In hot air drying, drying for 1 second to 5 minutes is more preferable because it improves the production efficiency.

The coating method of the chemical conversion treatment liquid is not particularly limited, and generally known coating methods such as roll coating, ringer roll coating, air spray, airless spray, and dipping can be employed. Further, it is more preferable to apply the resin on a continuous coating line called a general coil coating line or a sheet coating line which is fully equipped with these coating devices, because the coating work efficiency is good and mass production is possible.

The amount of the chemical conversion coating layer deposited is preferably 10 to 500 mg / m ² in terms of solid content. 10m
If it is less than g / m ² , sufficient processing adhesion cannot be ensured and
Even if it exceeds 0 mg / m ² , the processing adhesion is rather deteriorated.

The resin of the coating layer formed on the chemical conversion coating layer of the precoated metal sheet of the present invention may be any of water type, solvent type, powder type and the like. As the kind of resin, generally known ones, for example, polyacrylic resin, polyolefin resin, polyurethane resin, epoxy resin, polyester resin, polybutyral resin, melamine resin, etc. may be used as they are or in combination. You can

The coating layer of the precoated metal plate of the present invention contains 1 part of aluminum phosphate pigment per 100 parts by mass of resin solid content.
It is necessary to include ~ 140 parts by mass. If the addition amount of the aluminum phosphate pigment is less than 1 part by mass, it is not suitable because it has no effect on the galling of the coating film by the mold during press molding. The greater the amount of aluminum phosphate pigment added, the more effective it is against galling of the coating film during press molding, which is more preferable.
If it exceeds 140 parts by mass, the workability as a pre-coated metal plate is largely inferior, which is not suitable.

As the aluminum phosphate-based pigment, generally known ones such as aluminum dihydrogen tripolyphosphate and aluminum metaphosphate can be used, but aluminum dihydrogen tripolyphosphate is more easily available and more preferable. Commercially available aluminum dihydrogen tripolyphosphate, for example, "K-WHITE" manufactured by Teika can be used.

In the coating layer of the precoated metal sheet of the present invention, it is preferable to add a rust preventive pigment exhibiting a rust preventive effect in addition to the aluminum phosphate pigment, because the corrosion resistance is improved. It is preferable that the added amount of the rust preventive pigment is more effective, so that the total content of the aluminum phosphate pigment and the rust preventive pigment is 140 parts by mass or less based on 100 parts by mass of the resin solid content. . The total amount of aluminum phosphate pigment and rust preventive pigment added is 1
If it exceeds 40 parts by mass, there is a case where the workability when the precoated metal sheet is bent is greatly deteriorated, which is not preferable.

As the rust preventive pigment to be added to the coating layer of the precoated metal sheet of the present invention, generally known rust preventive pigments can be used. For example, (1) zinc phosphate, iron phosphate, and other phosphoric acid-based rust preventive pigments, (2) calcium molybdate, molybdenum aluminum, barium molybdate, and other rust preventive pigments, and (3) vanadium oxide. Vanadium rust preventive pigments such as (4) strontium chromate, zinc chromate, calcium chromate,
Chromate-based rust-preventive pigments such as potassium chromate and barium chromate (5) Water-dispersible silica, fumed silica, and fine-grained silica such as calcium ion-exchangeable silica can be used. However, it is desirable not to use the chromate rust preventive pigment described in (4) because it has an environmental problem. Further, among the silica-based pigments described in (5), calcium ion-exchangeable silica is environmentally harmless and has a large rust-preventing effect. Therefore, when it is added as a rust-preventing pigment, the rust-preventing effect is more exerted, which is preferable. Is. Calcium ion-exchangeable silica is manufactured by Grace's "Shielde
x "can be used. Further, these rust preventive pigments may be added in combination of plural kinds.

In the coating layer of the precoated metal sheet of the present invention, in addition to the aluminum phosphate-based pigment and the rust preventive pigment, a known pigment generally called an extender pigment or a coloring pigment for coloring is added in combination. be able to. An extender pigment is a generic term for pigments added to improve various properties required for a coating film, such as brittleness of the coating layer and hiding properties after coating, and plays a role such as filling and matting of the coating film. Examples thereof include talc that exhibits, titanium white (titanium oxide) that improves the hiding power of the coating film, and silica that improves the matteness of the coating film and the scratching property of the coating film.
It is preferable to add these extender pigments because the above-mentioned various performances are improved. The coloring pigments include titanium oxide (TiO ₂ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), alumina (Al ₂ O ₃ ), kaolin. Clay, carbon black, iron oxide (Fe ₂ O ₃ ,
Inorganic pigments such as Fe ₃ O ₄ ) and generally known coloring pigments such as organic pigments can be used. It is more preferable to use a plurality of these extender pigments and coloring pigments having different effects in combination, because the respective effects are exhibited.
When an extender pigment or a coloring pigment is added, the addition amount of all pigments, which is a total of aluminum phosphate pigments, rust preventive pigments, and extender pigment coloring pigments, is 14 per 100 parts by mass of the resin solid content in the paint.
It is preferable that the amount is 0 parts by mass or less. Addition amount of all pigments is 1
If it exceeds 40 parts by mass, problems such as a great deterioration in workability when the precoated metal plate is bent may occur.

The film thickness of the coating film containing the aluminum phosphate-based pigment of the precoated metal plate of the present invention is not particularly specified, but various performances of the coating film differ depending on the film thickness, and therefore it is appropriately selected as necessary. There is a need.

In order to form a coating layer containing the aluminum phosphate-based pigment of the precoated metal sheet of the present invention, a coating material containing the pigment in the amount specified in the present invention with respect to the resin solid content is prepared in advance, It is more preferable to apply this and dry-cure it because the production efficiency is improved. These paints can be used in any form such as solvent-based paints, water-based paints, melt-type paints, powder paints, electrodeposition paints, UV-curable paints, electron beam-curable paints. The coating method of these paints is a generally known coating method, for example, roll coating, curtain flow coating, roller curtain coating, die coating, air spray, airless spray, electrodeposition coating, powder coating, dipping, bar coating, brush coating. And so on. However, it is more suitable to coat with a continuous coating line called a general coil coating line or sheet coating line that is fully equipped with roll coat, curtain flow coat, and roller curtain coat, as it allows good coating work efficiency and mass production. . The dry baking method of this paint is hot air oven, open flame type oven,
A generally known dry curing method such as a far infrared oven or an induction heating oven can be used. Further, when the form of the coating material is an ultraviolet curable coating material, a generally known ultraviolet irradiation device can be used, and when it is an electron beam curing type coating material, a generally known electron beam irradiation device can be used.

In the precoated metal sheet of the present invention, an overcoat coating layer can be further provided on the coating layer containing the aluminum phosphate pigment. This is more preferable because it improves the color appearance, the design appearance, and other coating film performance of the coating appearance of the precoated metal sheet. The top coat film layer can be formed by applying a generally known top coat paint, followed by drying and baking to cure. Examples of generally known topcoat paints include polyester topcoat paints, epoxy topcoat paints, urethane topcoat paints, acrylic topcoat paints, and melamine-based topcoat paints. As the topcoat paint, any form such as solvent-based paint, water-based paint, powder paint, electrodeposition paint, ultraviolet curable paint, electron beam curable paint can be used. In the overcoat paint, generally known coloring pigments and extender pigments such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ). , Alumina (Al ₂ O ₃ ), kaolin clay, carbon black, iron oxide (Fe ₂ O ₃ ,
Fe ₃ O ₄ ), talc, silica and the like can be added. Further, the top coating is a generally known design coating,
For example, a yuzu skin tone paint, a fine paint, a hammer tone paint, a matte paint, a metallic paint, a pearl paint, a texture paint and the like can be used. The coating method of the topcoat paint is a generally known coating method, for example, roll coating, curtain flow coating, roller curtain coating, die coating, air spray, airless spray, electrodeposition coating, powder coating, dipping, bar coating,
It can be done by brushing. However, it is more suitable to coat with a continuous coating line called a general coil coating line or sheet coating line that is fully equipped with roll coat, curtain flow coat, and roller curtain coat, as it allows good coating work efficiency and mass production. . As a method for dry baking of the top coat, a generally known dry baking method such as a hot air oven, a direct fire type oven, a far infrared oven, an induction heating type oven or the like can be used. When the top coating material is an ultraviolet curable coating material, a generally known ultraviolet irradiation apparatus can be used, and when it is an electron beam curing type coating material, a generally known electron beam irradiation apparatus can be used.

[0032]

EXAMPLES The test materials used in the experiments will be described in detail below. 1. The following metal plates were used as test materials for the metal plate experiment. Hot-dip galvanized steel sheet (GI) : Plate thickness 0.6 mm, zinc adhesion amount 60 g / m ² per side (double-sided plating) Electrogalvanized steel sheet (EG) : Plate thickness 0.6 mm, zinc adhesion amount 20 g / m ² per side (Double-sided plating) 55% alloyed aluminum-galvanized steel plate (GL) : Plate thickness 0.
6 mm, 90 g / m ^{2 on} one side in terms of zinc adhesion (double-sided plating) Zn-11% Aluminum-3% Magnesium-0.2% Siri
Con-plated steel plate (SD) : 0.6 mm in plate thickness, 60 g / m ^{2 on} one side in terms of zinc adhesion (double-sided plating) Cold rolled steel plate (CR) : 0.6 mm in plate thickness 2. The following chemical conversion treatment liquids were prepared as the chemical conversion treatment liquids used for the test materials of the chemical conversion treatment experiment. Chemical conversion treatment liquid (A) : An aqueous solution containing 20 g / l of tannic acid, 40 g / l of silane coupling agent, and 20 g / l of finely divided silica was prepared as a pretreatment agent for metal. In addition, "tannic acid AL" manufactured by Fuji Chemical Industry Co., Ltd. was used for tannic acid, γ-glycidoxypropyltrimethoxysilane was used for the silane coupling agent, and "Snowtech-N" manufactured by Nissan Chemical Co., Ltd. was used for the fine silica. . Chemical conversion treatment liquid (B) : An aqueous solution containing 20 g / l of tannic acid, 40 g / l of silane coupling agent, 20 g / l of finely divided silica, and 20 g / l of polyester resin was prepared as a pretreatment agent for metal. In addition, "tannic acid AL" manufactured by Fuji Chemical Industry Co., Ltd. for tannic acid, γ-glycidoxypropyltrimethoxysilane for silane coupling agent, "Snowtech-N" manufactured by Nissan Chemical Co., Ltd. for fine silica, polyester resin Includes Finetex ES-65 manufactured by Dainippon Ink and Chemicals.
0 ”was used. Chemical conversion treatment liquid (C) : For comparison with the present invention, a commercially available coating chromate treatment "ZM-" manufactured by Nippon Parkerizing Co., Ltd.
1300AN "was used. Chemical conversion treatment liquid (D) : For comparison of the present invention, a commercially available zinc phosphate treatment "PALBOND" manufactured by Nippon Parkerizing Co., Ltd. was used. 3. Aluminum phosphate pigment-containing paints Commercially available polyester-based, urethane-based, epoxy-based clear paints that do not contain pigments at all are added aluminum phosphate-based pigments and, if necessary, rust preventive pigments, and stirred to form paints. Created. For aluminum phosphate pigments, "K
-G105 "was used. As the rust preventive pigment, "NP-530" manufactured by Toho Pigment Co., Ltd. as a zinc phosphate-based rust preventive pigment (described as "Zn phosphate" in the table) and as calcium ion-exchangeable silica "Shieldex-" manufactured by Grace Co. C3
03 ”(described as“ Ca—Si ”in the table) and commercially available strontium chromate as a chromium-based rust preventive pigment (described as“ Sr—Cr ”in the table). The amount of each pigment added is shown in Table 1. In addition, as an extender pigment, “Aerosil 300” manufactured by Japan Aerosil Co., Ltd. (described as “silica” in the table) as a commercially available fine silica, and titanium oxide “CR- manufactured by Ishihara Sangyo Co., Ltd.” as a white pigment, if necessary. 9
5 ”(described as“ titanium white ”in the table) was added. The amount of each pigment added is shown in the table. 4. Topcoat paint Commercially available polyester topcoat paint "FL100HQ" manufactured by Nippon Paint Co., Ltd. was used. The color used was white. 5. Backside paint A commercially available polyester topcoat paint "FL100HQ" manufactured by Nippon Paint Co., Ltd. was used. The color used was gray. 6. Preparation of Pre-coated Metal Plate Various metal plates were degreased by immersing them in an aqueous solution of FC-364S (manufactured by Nippon Parkerizing Co., Ltd.) at a concentration of 2% by mass and a temperature of 60 ° C. for 10 seconds, washed with water, and then dried. Then, the chemical conversion treatment liquids (A), (B), (C) and (D) were applied on both sides of the metal plate by a roll coater and dried in a hot air drying oven to obtain a chemical conversion treatment coating layer. The amount of chemical conversion treatment applied is
In the case of the chemical conversion treatment liquids (A), (B) and (D), coating was performed so that the adhesion amount of the entire dry film was 200 mg / m ² . In the case of the chemical conversion treatment liquid (C), coating was performed so that the adhesion amount was 50 mg / m ^{2 in} terms of metallic chromium. As for the test piece using the chemical conversion treatment liquid (E), the degreased metal plate was immersed in the chemical conversion treatment liquid (E) for 2 minutes and dried in a hot air drying oven to obtain a chemical conversion treatment film layer. The chemical conversion treatment (E) was applied such that the amount of zinc phosphate adhered was 2 g / m ² . The ultimate plate temperature during the chemical conversion treatment drying was 60 ° C. Next, a coating containing an aluminum phosphate pigment is applied on one side by a roll coater to a film thickness of 5 μm after drying, and the other side is coated by a back coater by a roll coater on the dried film. Thick 5
A coating layer was obtained by coating so as to have a thickness of μm, and drying and curing in an induction heating furnace in which hot air was blown, under the condition that the ultimate plate temperature of the metal plate was 210 ° C. After drying and baking, the coated metal plate was wiped with water by spraying and cooled with water. Further, a top coat paint is applied on a coating layer containing an aluminum phosphate pigment by a roll coater so that the film thickness after drying becomes 15 μm, and the ultimate plate temperature of the metal plate is reached by an induction heating furnace in which hot air is blown. Was baked at a temperature of 230 ° C. After drying and baking, the coated metal plate was wiped with water by spraying and cooled with water to obtain a pre-coated metal plate as a test material.

The following evaluation tests were carried out on the precoated metal sheet thus prepared. In each test, the surface coated with the paint containing the aluminum phosphate pigment was used as the evaluation surface. 1. Coating Film Processing Adhesion Test The prepared precoated metal plate was bent by 180 °, and the coating film in the processed portion was observed with a 20-fold loupe to check for cracks in the coating film. In the bending test, bending was performed so that the surface coated with the paint containing the aluminum phosphate pigment was the outside. In addition, an adhesive tape was attached to the processed portion, and the remaining state of the coating film was visually observed when the adhesive tape was peeled off vigorously. In this test, tape peeling was performed twice. The bending process was 0T processing in an atmosphere of 20 ° C.

The evaluation of coating film cracking is ⊚ when there is no coating film cracking, and ◯ when there are about 1 to 3 very small cracks in the coating film.
When the coating film had very small cracks on the entire surface, it was evaluated as Δ, and when the coating film had large visible cracks on the entire surface of the processed part, it was evaluated as x.

Further, the evaluation of the state of the coating film remaining after peeling off with the tape is ⊚ when it remains on the plated steel sheet without peeling at all, and ◯ when the coating film partially peels off. The case where the coating film was partially peeled off was evaluated as Δ, and the case where peeling was observed over almost the entire bent portion was evaluated as x.

Further, the precoated metal plate was processed to 0T, immersed in boiling water for 1 hour, taken out and allowed to stand for 24 hours, and the coating film was peeled off with a tape. Evaluation of the coating film remaining state,
◎ when it remains on the plated steel sheet without peeling at all,
The case where the coating film was slightly peeled off was evaluated as ◯, the case where the coating film was partially peeled off was marked as Δ, and the case where peeling was observed over almost the entire bent portion was evaluated as x. 2. Coating scuffing test by beads Bead coating scuffing test by bead, which is a test method that reproduces the peeling of the coating film that occurs when the coating film of the precoat metal plate is galvanized by the press die when the precoat metal plate is press molded Method ”(publication technique 95-1078). First, make the pre-coated metal plate 30 mm
A test piece of (width) × 300 mm (length) is cut out, and the test piece is sandwiched between a flat mold and a mold provided with a bead having a radius of 3 mmR. At this time, the test piece was sandwiched so that the bead of the mold could be pressed against the surface coated with the paint containing aluminum phosphate pigment (evaluation surface), and a load of 1 t was applied to the pre-coated metal plate. It was pressed against the evaluation surface of. In this state, the pre-coated metal plate is 200 mm / m
The state of peeling of the coating film on the evaluation surface of the precoated metal plate, which was pulled out at a speed of in and rubbed with a bead, was visually observed and evaluated.

The evaluation is ⊚ when the coating film is not peeled at all, ◯ when it is extremely peeled off, and about 20% or more in terms of the area ratio of the portion rubbed by the beads. The case was designated as Δ, and the case where the entire surface was peeled was designated as ×. 3. Corrosion resistance test A cut scratch that penetrates the coating film to the metal plate with a cutter is made on the surface of the prepared precoated metal plate coated with paint containing aluminum phosphate pigment, and further, for the end face part, at the time of cutting A sample for corrosion resistance test was prepared by cutting so that the return (burr) was on the surface coated with the backside coating (so that it became the lower burr). And the salt spray test was implemented by the method of 9.1 of JISK5400. Salt water
The surface containing the paint containing the aluminum phosphate pigment was wiped and sprayed. The test time is 120 hours when the original plate of the pre-coated metal sheet is a cold-rolled steel sheet, 240 hours when it is an electrogalvanized steel sheet, hot-dip galvanized steel sheet, 55
% Alloyed Aluminum Zinc Plated Steel, Zn-11% Aluminum-
In the case of a 3% magnesium-0.2% silicon plated steel sheet, it was set to 360 hours.

The method for evaluating the coating film at the cut portion is ⊚ when the maximum swelling width on one side of the cut is less than 1 mm.
○ when less than m, △ when 3 mm or more and less than 5 mm,
When it was 5 mm or more, it was evaluated as x.

Further, the method for evaluating the cut end surface is as follows: ⊚ when the swollen width from the end surface is within 2 mm, ○ when 2 mm or more and less than 3 mm, Δ when 3 mm or more and less than 5 mm,
When it was 5 mm or more, it was evaluated as x.

[0040]

[Table 1]

[0041]

[Table 2]

Details of the evaluation results will be described below.

The evaluation test results of the prepared precoated metal plate are shown in the table. The pre-coated metal sheets of the present invention (Examples of the present invention-Nos. 1 to 22) use a conventional chromate-free chemical conversion treatment such as zinc phosphate treatment (Comparative Example-N).
o. Compared with 28), the coating film is less likely to peel off in the scuffing test of the coating film with beads, which is preferable. Furthermore, the aluminum phosphate-based material is not added to the coating layer on the chemical conversion coating (Comparative Example-
No. 23) and aluminum phosphate pigments have a resin solid content of 100.
Less than 1 part by mass relative to parts by mass (Comparative Example-No. 2
Even when compared with 4), the coating film is less likely to peel off in the galling test of the coating film with beads, which is preferable. Further, the precoated metal plate of the present invention, by containing a polyester resin in the chemical conversion treatment film layer, the processing adhesion of the coating film is improved, and the coating film is less likely to peel off even in the galling test of the coating film by beads. ,
It is more preferable (Comparative example of the present invention-No. 1 and No. 10). Compared to the one in which the rust preventive pigment was added to the paint in addition to the aluminum phosphate-based pigment (Invention example-No. 8 to 22) (Invention example-No. 2 to 7) Corrosion resistance is improved, which is preferable. In particular, the rust preventive pigment is calcium ion-exchangeable silica (Inventive Example-No. 1, 8 to 1).
No. 4, 17 to 22), the corrosion resistance is further improved, and moreover, it has the same corrosion resistance as those in which the conventional chromate-based rust preventive pigment is added (Invention Example-No. 16 and Comparative Example-No. 26). Therefore, it is preferable.

[0044]

EFFECTS OF THE INVENTION The present invention provides a precoated metal sheet which is excellent in process adhesion and corrosion resistance of a coating film and which is very suitable for press molding, without using hexavalent chromium, which may have an environmental impact. It has become possible. Therefore, it can be said that the present invention has an extremely high industrial value.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshio Kizen             1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel shares             Company Kimitsu Works F-term (reference) 4D075 AE03 BB73Y CA09 CA13                       CA33 DA06 DB02 DB04 DB05                       DB07 DC01 DC10 DC11 DC15                       DC18 DC38 DC41 EA06 EA07                       EA10 EB13 EB19 EB22 EB32                       EB33 EB35 EB38 EB56 EC01                       EC03 EC07 EC11 EC15 EC45                       EC54                 4F100 AA04C AA04H AA20B AA20C                       AA20H AB01A AB01D AJ02B                       AK41B BA03 BA04 BA05                       BA06 BA07 BA10A BA10C                       CA13C CA14C CC00B EH71D                       EJ67B EJ68B GB07 GB16                       GB32 GB48 GB81 GB90 JB02                       JL01 JM02B YY00C                 4K026 AA02 AA04 AA07 AA09 AA12                       AA13 AA22 BA08 BA12 BB08                       BB09 CA13 CA37 CA38 CA39                       CA41 EB02 EB08 EB11                 4K044 AA02 AA03 AA06 AB02 BA10                       BA12 BA17 BA19 BA21 BB03                       BB04 BB05 BB09 BB11 BC02                       BC05 CA11 CA16 CA18 CA53                       CA62

Claims (9)

[Claims] 1. A chemical conversion coating layer containing at least one of tannin or tannic acid, a silane coupling agent, and fine silica as a solid content on one or both sides of a metal plate, and a resin on the chemical conversion coating layer. A precoated metal sheet having excellent press formability, which further comprises a coating layer containing 1 to 140 parts by mass of an aluminum phosphate pigment with respect to 100 parts by mass of solid content. 2. The chemical conversion treatment film layer, as a solid content,
The precoated metal sheet having excellent press formability according to claim 1, further comprising a polyester resin. 3. The precoated metal sheet having excellent press formability according to claim 1, wherein the aluminum phosphate-based pigment contained in the coating layer is aluminum tripolyphosphate. 4. The coating layer further contains an anticorrosive pigment,
The press molding according to any one of claims 1 to 3, wherein the total content of the rust preventive pigment and the aluminum phosphate pigment is 140 parts by mass or less with respect to 100 parts by mass of the resin solid content. Pre-coated metal plate with excellent properties. 5. A rust preventive pigment contained in the coating layer,
The precoated metal sheet having excellent press formability according to claim 4, which is a calcium ion-exchangeable silica. 6. The pre-coated metal plate having excellent press formability according to claim 1, wherein the metal plate is a metal plate having a plating layer on one side or both sides. 7. A chemical conversion treatment film layer is formed by coating a treatment liquid containing at least one of tannin and tannic acid, a silane coupling agent and fine silica particles on one or both surfaces of a metal plate and drying the coating liquid. Furthermore, 1 to 1 part of aluminum phosphate pigment is added to 100 parts by mass of resin solid content.
A method for producing a precoated metal sheet having excellent press formability, which comprises applying a coating material containing 40 parts by mass and drying and curing it. 8. The method for producing a precoated metal sheet having excellent press formability according to claim 7, wherein the treatment liquid further contains a polyester resin. 9. The coating composition further contains a rust preventive pigment, and the total content of the rust preventive pigment and the aluminum phosphate pigment is 140 parts by mass or less based on 100 parts by mass of the resin solid content. The method for producing a precoated metal sheet having excellent press formability according to claim 7 or 8.