JP2006321957A - Aqueous surface-treating agent for environmental response type pre-coated metal material and surface-treating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-chromium based aqueous surface-treating agent useful as a substrate-treating agent for forming pre-coated metal materials having excellent coating adhesiveness, corrosion resistance and coin scratch resistance. <P>SOLUTION: This aqueous surface-treating agent for environmental response type pre-coated metal materials contains a silane coupling agent (A) and a vanadium-containing compound and/or tungsten-containing compound (B) in a vanadium atom and/or tungsten atom/(A) solid content mass ratio of 0.1/100 to 40/100. The coating adhesiveness and the coin scratch resistance are further improved by further compounding the surface-treating agent with water-dispersible silica (C). When an amino functional group-containing silane coupling agent is used, coating adhesiveness is excellent. When an amino group (primary or secondary)-containing silane coupling agent and a silane coupling agent having an epoxy group bound to adjacent carbon atoms are together used, the corrosion resistance is further improved. A method for treating the surface of an environmental response type pre-coated metal material is characterized by coating the surface of the metal material with the aqueous surface-treating agent and then drying the coated aqueous surface-treating agent to form the dried coating film of 0.01 to 1 g/m<SP>2</SP>. A method for producing a non-chromium-based pre-coated metal material is characterized by applying a chromium-free top coating to the metal material surface-treated by the surface-treating method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-chromium-based aqueous surface treatment agent useful as a base treatment agent for producing a pre-coated metal material excellent in coating adhesion, corrosion resistance, and coin scratch resistance, a treatment method, and a method for producing a non-chromium-based pre-coated metal material. Is.

  Conventional post-painted products that have been painted after processing on parts for home appliances, building materials, automobiles, etc. have been subjected to many pre-treatments such as phosphates. Instead of pretreatment, precoated metal sheets coated with a colored organic film have been used. This metal plate is obtained by coating an organic film on a metal plate and a plated metal plate that have been subjected to a base treatment, and has the characteristics of having good workability and good corrosion resistance while having an aesthetic appearance.

  For example, Patent Document 1 discloses a pre-coated steel sheet in which end face corrosion resistance is improved by applying a specific chromate treatment liquid and drying without washing. Pre-coated steel sheets with such chromium-containing ground treatment have corrosion resistance and workability and paint adhesion due to the combined effects of chromate treatment and organic coating, and omit post-processing coating to improve productivity. It is intended for quality improvement and is currently used for general purposes. However, due to the toxicity problem of hexavalent chromium that may be eluted from the chromate-treated film and the organic film containing the chromium-based rust-preventive pigment, recently there has been a growing demand for non-chromium anti-rust treatment and non-chromium organic film.

  The first characteristic required for the pretreatment of the precoated steel sheet is coating adhesion, and it is required that the two interfaces with the underlying metal as the lower layer and the primer as the upper layer adhere well. This coating adhesion may be evaluated after being immersed in boiling water for a predetermined time. This is particularly called secondary coating adhesion, and is distinguished from coating primary adhesion which is coating adhesion before being immersed in boiling water. Both the primary and secondary adhesion properties are extremely important characteristics essential for pre-coated steel sheets that are premised on being processed into complicated shapes by post-processing. The T-bending test is an extremely severe test and is used for evaluating the adhesion of precoated steel sheets.

  As a second characteristic required for the pretreatment of the precoated steel sheet, there is a coin scratch resistance. This is a characteristic influenced not only by adhesion but also by the film hardness of the ground treatment.

  The third characteristic required for the pretreatment of the precoated steel sheet is corrosion resistance. In the case of a pre-coated steel plate, usually, a base treatment, a primer coating treatment, and a top coat coating treatment are sequentially performed on the steel plate. In the case of a precoated steel sheet subjected to conventional chromate treatment, chromate is contained not only in the base treatment layer but also in the primer layer. In particular, the primer layer, which is used as thick as 3 to 10 μm, contains many chromium components as anti-corrosion pigments, as compared to the base treatment that is not normally used exceeding 0.5 μm, and plays a major role in imparting corrosion resistance to precoated steel sheets. Is responsible. However, the actual condition is that the primer in the precoated steel sheet not containing chromium can only provide corrosion resistance that does not reach the primer containing the chromium-based rust preventive pigment. Therefore, it can be said that in the non-chromate pre-coated steel sheet, the base treatment part plays a role of imparting corrosion resistance rather than the conventional chromate system.

  In addition, the pre-coated steel sheet also has applications that require heat resistance, such as the outer plate of a microwave oven, and in general, the resin is weak against heat and causes deterioration in adhesion after heating history. It is desired that the base does not contain a resin.

  As a non-chromium-based antirust treatment method that replaces chromate treatment, Patent Document 2 describes that white rust resistance and paint adhesion can be achieved by surface-treating zinc and a zinc alloy with an aqueous solution containing tannic acid and a silane coupling agent. Although the technique to improve is disclosed, by this method, the coin scratch resistance and corrosion resistance required for the precoated metal sheet cannot be sufficiently ensured. Patent Document 3 discloses forming a chemical conversion film containing silica fine particles and a binder such as polyacrylic acid on the surface of a galvanized steel sheet. However, with this method, the paint adhesion and corrosion resistance required for the precoated steel sheet are not as good as those when the chromate treatment is performed.

  Patent Document 4 discloses a technique for imparting primary rust resistance by surface-treating the surface of a galvanized steel sheet with an aqueous solution containing silica fine particles, a silane coupling agent, and a resin composition. However, when this treatment agent is diverted to a precoated steel sheet, the performance as a coating base for a precoated steel sheet that requires strict adhesion is not sufficient. The adhesion achieved by the treatment liquid for imparting temporary rust resistance is Erichsen extrusion level processing adhesion, and the level of processing adhesion that passes the T-bending test is not achieved. The same can be said for a case where a fingerprint-resistant chemical or a lubricating chemical is diverted to the pretreatment steel sheet surface treatment agent, and it cannot withstand a strict T-bending adhesion test.

  In Patent Document 5, the surface of a plated steel sheet is treated with an aqueous solution containing water-dispersible silica, a silane coupling agent, a zirconium compound or a titanium compound, a thiocarbonyl group-containing compound, an acrylic resin and phosphoric acid. Processing techniques are disclosed. The inhibitory action by the thiocarbonyl group-containing compound and phosphoric acid is insufficient, and it is not as good as the chromate-treated precoated steel sheet in terms of the corrosion resistance as the precoated steel sheet, particularly the corrosion resistance of the end face.

In Patent Document 6, although not a plated steel sheet, the steel material is immersed in a treatment warm bath containing a silane coupling agent and molybdenum, and then washed with water to form a reaction-treated undercoat, and an anticorrosion coating treatment is applied as an upper layer. A method for producing an anticorrosion coated steel material is disclosed. This technique cannot be applied to precoated steel sheets because it requires immersion and water washing steps. In addition, since the molybdenum compound is a first-class compound specified by PRTR (Pollution Release and Transfer Register) (environmental pollutant discharge transfer registration), it is difficult to say that it is environmentally friendly.
Japanese Patent Laid-Open No. 3-100180 JP 59-116381 A JP 2002-80979 A JP 2001-164195 A JP 2001-316845 A JP 2003-34881 A

  The present invention provides an aqueous surface treatment agent that is excellent in coating adhesion, corrosion resistance, and coin scratch resistance of a coating film when used as a coating base in a pre-coated steel sheet while being an environment-friendly non-chromium system, and a surface on which the coating is applied It is an object of the present invention to provide a pre-coated steel sheet that is excellent in the treatment method and paint adhesion, corrosion resistance and coin scratch resistance using the same.

The above issues
(1) The silane coupling agent (A), the vanadium-containing compound and / or the tungsten-containing compound (B) is 0.1 / 100 as a solid content mass ratio of vanadium atoms and / or tungsten atoms / (A). An aqueous surface treating agent for environmentally friendly pre-coated metal materials, contained in a range of ˜40 / 100;
(2) The aqueous surface treating agent according to the above (1), wherein 0.2% by mass or more of the entire silane coupling agent (A) is a silane coupling agent having an amino functional group;
(3) The silane coupling agent (A) comprises a silane coupling agent having a primary amino group or a secondary amino group and a silane coupling agent having a functional group capable of reacting with an amino group. The aqueous surface treating agent according to the above (1) or (2), wherein the equivalent ratio of is from 50: 1 to 1:50;
(4) The aqueous surface treating agent according to (3) above, wherein the silane coupling agent having a functional group capable of reacting with an amino group is a silane coupling agent having an epoxy group bonded to an adjacent carbon atom;
(5) The water dispersible silica (C) is further contained in a range of 1/50 to 10/1 as a solid content mass ratio of (C) / (A). The aqueous surface treatment agent according to item 1; and (6) The aqueous surface treatment agent according to any one of (1) to (5) above is applied to the surface of the metal material and then dried, and 0.01 to 1 g A surface treatment method of a metal material corresponding to the environment characterized by forming a dry film of / m ² ; and (7) the metal material surface-treated by the surface treatment method of (6) above further contains chromium This is achieved by a method for producing an environmentally-friendly pre-coated metal material characterized in that there is no overlayer coating.

  The pre-coated metal material obtained by applying an upper layer coating not containing chromium to the metal material surface-treated by the water-based surface treatment agent for environmentally-friendly pre-coated metal material and the surface treatment method of the present invention has a coating layer containing chromium. Despite the absence, it has excellent corrosion resistance, paint adhesion (primary paint adhesion and secondary paint adhesion) and coin scratch resistance. Therefore, the present invention has extremely high industrial value.

The present invention is described in detail below.
The water-based surface treatment agent for environmentally-friendly precoat metal materials of the present invention is a water-based surface treatment agent containing a silane coupling agent (A) and a vanadium-containing compound and / or a tungsten-containing compound (B) as essential components.

  The silane coupling agent has a high activity of -OH of silanol groups generated by hydrolysis, and forms a strong chemical bond of -Si-OM through an oxygen atom and the base metal M which is a base material. This chemical bond particularly contributes to good adhesion to the base metal. Moreover, the reaction with the organic functional group contained in the upper layer may also contribute to improving the adhesion with the upper layer. When a polar group having strong polar O, N or the like as a constituent element is introduced as a functional group of the silane coupling agent, the adhesion with the upper layer is further improved.

  Examples of silane coupling agents applicable to the present invention include N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, and N-β (aminoethyl). γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxy Silane, N-phenyl-γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane , 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-glycidoxypropylmethyl Dimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercapto Propylmethyldimethoxysilane, γ-mel Captopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloro Propylmethyldimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropylmethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-anilinopropyl Triethoxysilane, γ-anilinopropylmethyldiethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysila , 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. Of these, only one component can be used, or a plurality can be used in combination.

  In many cases, the base treatment agent is somewhat compatible with the primer applied to the upper layer, and depending on the combination, the performance may not appear as expected. Among the above coupling agents, those having an amino functional group are not easily affected by compatibility with the upper layer. Therefore, in the aqueous surface treatment agent (primary treatment agent) of the present invention, it is preferable that the silane coupling agent (A) contains at least one having an amino functional group. Here, in the present invention, the amino functional group means a functional group selected from a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group. In addition, as a counter ion in the case of having a quaternary ammonium group, a halogen ion such as a chlorine ion, a phosphate ion, a nitrate ion, a sulfate ion, and an organic acid ion are exemplified. The amount of the silane coupling agent having an amino functional group used relative to the entire silane coupling agent (A) is preferably 0.2% by mass or more and 2.0% by mass or more, based on the solid content. More preferably, it is more preferably 10% by mass or more, so that depending on the type of primer, adhesion to the primer (coating adhesion) can be prevented from being adversely affected or minimized. it can.

  When two or more types are used as the silane coupling agent (A), the silane coupling agent having a primary amino group or a secondary amino group and a functional group capable of reacting with the amino group, for example, bonded to adjacent carbon atoms It is preferable to use a silane coupling agent having an epoxy group (glycidyl group, 3,4-epoxycyclohexyl group, etc.). The use ratio of these silane coupling agents does not need to be an amount in which the functional groups react with each other without excess or deficiency, and reacts with a silane coupling agent having a primary amino group or a secondary amino group and an amino group. The equivalent ratio to the functional group that can be used is preferably in the range of 50: 1 to 1:50, more preferably in the range of 10: 1 to 1:10, and the primary amino group or secondary group. In the case of using a combination of a silane coupling agent having an amino group and a silane coupling agent having an epoxy group bonded to an adjacent carbon atom, the effect of the silane coupling agent having an amino functional group on the coating adhesion In addition, the corrosion resistance can be further improved.

The vanadium-containing compound and / or the tungsten-containing compound (B), which is the second essential component of the aqueous surface treating agent of the present invention, acts as an inhibitor (corrosion-inhibiting substance) and improves corrosion resistance. Component (B) includes vanadium or tungsten carbonate, oxide, hydroxide, nitrate, sulfate, phosphate, fluoride, fluoro acid or salt thereof, oxo acid salt, organic acid salt, vanadium or tungsten. Contains organic compounds. As specific compounds, vanadium pentoxide (V), vanadium trioxide (III), vanadium dioxide (IV), vanadium hydroxide (II), vanadium hydroxide (III), vanadium sulfate (II), vanadium sulfate (III) , Vanadium oxysulfate (IV), vanadium fluoride (III), vanadium fluoride (IV), vanadium fluoride (V), hexafluorovanadate (III) or a salt thereof (potassium salt, ammonium salt, etc.), metavanadate (V) or a salt thereof (sodium salt, ammonium salt, etc.), vanadium oxyacetylacetonate (IV) [VO (OC (═CH ₂ ) CH ₂ COCH ₃ ) ₂ ], vanadium acetylacetonate (III) [V ( O—C (═CH ₂ ) CH ₂ COCH ₃ ) ₃ ]; Ten (IV), tungsten oxide (V), tungsten oxide (VI), tungsten fluoride (IV), tungsten fluoride (VI), tungstic acid (VI) or a salt thereof (ammonium salt, sodium salt, etc.), metatungsten Examples thereof include acid salts (VI) (ammonium salts, sodium salts, etc.), paratungstate salts (VI) (ammonium salts, sodium salts, etc.) and the like. These vanadium-containing compounds and tungsten-containing compounds can be used alone or in combination of two or more.

The vanadium-containing compound and / or the tungsten-containing compound (B) has a mass ratio of vanadium atoms and / or tungsten atoms / (A) to the solid content of the silane coupling agent (A) of 0.1 / 100 to 40 / It is preferably contained in the range of 100, more preferably in the range of 0.3 / 100 to 20/100, and even more preferably in the range of 1/100 to 10/100. When a plurality of vanadium-containing compounds and / or tungsten-containing compounds are used in combination, the total amount only needs to satisfy the above range.
Although the mechanism for improving the corrosion resistance of the vanadium-containing compound and / or the tungsten-containing compound is not clear, it seems that the point is that several valences can be taken. The effect of addition appears from the addition of 0.1 / 100. However, addition of an excessive amount exceeding 40/100 may cause a decrease in coating secondary adhesion, depending on the type of primer applied to the upper layer.

  In the unlikely event that the liquid stability of the treatment agent deteriorates due to the addition of the vanadium-containing compound and / or the tungsten-containing compound (B), acetic acid, propionic acid, oxalic acid, gluconic acid, tartaric acid, malic acid, ascorbine The liquid stability can be improved by appropriately adding an organic acid containing a carboxyl group such as an acid or tannic acid.

  The aqueous surface treating agent of the present invention may contain water-dispersible silica (C). The addition of water-dispersible silica (C) contributes to the improvement of the adhesion to the metal material based on the strong polar effect of oxygen, and the surface of the film to be formed has irregularities due to the water-dispersible silica, and the anchor effect. Improves adhesion to the upper layer (coating adhesion). However, excessive addition facilitates the penetration of water into the interface and may reduce the coating secondary adhesion. Further, the water-dispersible silica (C) increases the hardness of the undercoat and contributes to the improvement of the coating adhesion, so that it effectively acts on the improvement of the coin scratch resistance.

  Examples of the water-dispersible silica include liquid phase silica synthesized from a liquid phase and gas phase silica synthesized from a gas phase, and any of them can be used in the present invention. Although it does not specifically limit as a liquid layer silica, Snowtex C, Snowtex O, Snowtex N, Snowtex S, Snowtex UP, Snowtex PS-M, Snowtex PS-L, Snowtex 20, Examples include Snowtex 30 and Snowtex 40 (both manufactured by Nissan Chemical Industries, Ltd.). The gas phase silica is not particularly limited, and examples thereof include Aerosil Co., Ltd. 50, Aerosil 130, Aerosil 200, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil MOX80, Aerosil MOX170 (all manufactured by Nippon Aerosil). It is done. These can be used alone or in combination.

  The amount of water-dispersible silica (C) used is preferably in the range of 1/50 to 10/1 as the solid content mass ratio of (C) / (A) to the silane coupling agent (A). The range of 1/30 to 4/1 is more preferable, and the range of 1/10 to 2/1 is even more preferable.

  Although there is no restriction | limiting in particular about pH of the aqueous surface treating agent of this invention, It is preferable that it is 3-10, and it is more preferable that it is 5-9. When using the silane coupling agent which has an amino functional group, it is preferable that the pH is 7-9. At this time, an appropriate acid (eg, acetic acid, phosphoric acid, etc.) or alkali (eg, ammonia, organic amine, etc.) can be used to control the pH.

  The aqueous surface treatment agent of the present invention further includes, as an optional component, a water-soluble resin for softening the treatment film, a surfactant called a wettability improver for obtaining a uniform film on the coated surface, and a thickening agent. An additive such as an agent, a conductive material for improving weldability, and a color pigment for improving designability may be appropriately blended.

The medium of the aqueous surface treatment agent of the present invention is water. Although there is no restriction | limiting in particular about the total solid content density | concentration in the aqueous surface treating agent of this invention, It is preferable that a total solid content density | concentration is about 1-20 mass% in consideration of coating-film formation property and operativity.
The aqueous surface treatment agent of the present invention comprises a silane coupling agent (A), a vanadium-containing compound and / or a tungsten-containing compound (B), water-dispersible silica (C) as an optional component, and other additions when used. It can manufacture by adding an agent to water and stirring, and there is no restriction | limiting in particular about the addition order of each component.

  Examples of the metal material to which the aqueous surface treatment agent of the present invention is applied include cold-rolled steel sheet, hot-rolled steel sheet, hot-dip galvanized steel sheet, electrogalvanized steel sheet, hot-dip galvanized steel sheet, aluminum-plated steel sheet, and aluminum-zinc alloy-plated steel sheet. Metal materials including generally known metal plates such as steel plates such as stainless steel plates, aluminum plates, copper plates, titanium plates, magnesium plates, and other plated metal plates can be used.

  Prior to applying the aqueous surface treating agent of the present invention to a metal material, the metal material can optionally be subjected to usual treatments such as hot water washing, alkali degreasing, and surface conditioning.

  The aqueous surface treating agent of the present invention can be applied to a metal material by a usual coating method such as roll coating, curtain flow coating, air spray, airless spray, dipping, bar coating, brush coating, and the like. Although it dries after application | coating, there is no restriction | limiting in particular in a drying method, drying temperature, and drying time, What is necessary is just the temperature and time which a water | moisture content evaporates. For example, what is necessary is just to dry by making the highest achieved temperature of metal materials, such as the apply | coated metal plate, into 60-120 degreeC in oven.

The coating amount of the aqueous surface treatment agent of the present invention is required to be in the range of 0.01 to 1 g / m ² as a dry film amount, and in the range of 0.02 to 0.4 g / m ^2. Is more preferable, and the range of 0.05 to 0.2 g / m ² is more preferable. If the coating amount is less than 0.01 g / m ² , the coating amount is too small, and the coating amount varies depending on the part, and the adhesion (adhesion to the metal material and the upper layer) tends to be insufficient. On the other hand, when the coating amount exceeds 1 g / m ² , the coating adhesion tends to be insufficient, and the cost is disadvantageous.

  The treatment with the aqueous surface treatment agent of the present invention is usually performed as a ground treatment in a pre-coated metal material as described below, but can also be carried out as a ground treatment in a laminated steel sheet.

  The present invention also relates to a method for producing a pre-coated metal material. The manufacturing method of the precoat metal material of this invention is a method of forming the upper film layer which does not contain chromium on the film | membrane formed by apply | coating the aqueous surface treating agent of this invention to a metal material, and drying. The upper film layer is usually composed of a non-chromate primer layer and a top coat layer formed on the non-chromate primer layer (the top coat layer usually does not contain chromium), and the upper film layer is the aqueous surface treatment agent of the present invention. It can be formed by applying a non-chromate primer on the film formed by applying and drying and then applying a top coat thereon. Further, the upper film layer may consist of only the top coat layer. In this case, the upper film layer is coated with the top coat on the film formed by applying the aqueous surface treatment agent of the present invention and drying. Can be formed.

  As the non-chromate primer that can be used in the present invention, any primer can be used as long as it does not use a chromate rust preventive pigment during the blending of the primer. The base resin of the non-chromate primer may be in any form such as water, solvent, and powder. Generally known resins such as polyacrylic resins, polyolefin resins, polyurethane resins, epoxy resins, polyester resins, polybutyral resins, melamine resins, etc. may be used as they are or in combination. it can. As rust preventive pigments, generally known ones such as (1) phosphoric acid rust preventive pigments such as zinc phosphate, iron phosphate and aluminum phosphate, (2) calcium molybdate, ammonium molybdate, barium molybdate, etc. Molybdic acid-based rust preventive pigments, (3) vanadium-based rust preventive pigments such as vanadium oxide, and (4) finely divided silica such as water-dispersible silica and fumed silica can be used. About the compounding quantity on the solid content standard of each component with respect to the whole non-chromate primer, it is preferable that the compounding quantity on the solid content standard of the rust preventive pigment with respect to the whole non-chromate primer is 1 to 40% by mass. When the blending amount of the rust preventive pigment is less than 1% by mass, the corrosion resistance is not sufficient, and when it exceeds 40% by mass, the workability is lowered.

 The applied film thickness of the primer is preferably 1 to 30 μm in terms of dry film thickness. When the thickness is less than 1 μm, the corrosion resistance decreases, and when it exceeds 30 μm, the adhesion during processing decreases. There are no particular limitations on the baking and drying conditions of the non-chromate primer, and for example, it can be 10 to 5 minutes at 130 to 250 ° C.

  The top coat is not particularly limited, and any ordinary top coat for painting can be used. The base resin of the top coat may be in any form such as water, solvent, and powder. Generally known resins such as polyacrylic resins, polyolefin resins, polyurethane resins, epoxy resins, polyester resins, polybutyral resins, melamine resins, etc. may be used as they are or in combination. it can. Coloring pigments may be added to the top coat, and there are no particular restrictions on the coloring pigments. Titanium white, zinc yellow, alumina white, carbon black, bengara, yellow iron oxide, molybdate orange, zirconium oxide (IV) And inorganic pigments such as Hansa Yellow, pyrazolone orange, and azo pigments. In addition, the top coat may contain the above-mentioned rust preventive pigments as appropriate, and may also contain additives such as antifoaming agents, leveling agents, dispersion aids, and diluents for reducing paint viscosity. Also good.

  The top coat is preferably 3 to 40 μm in dry film thickness. If it is less than 3 μm, the corrosion resistance is lowered, and if it exceeds 40 μm, the adhesion is lowered and the cost is increased. There is no restriction | limiting in particular about the baking drying conditions of the said topcoat, For example, it can be 10 seconds-20 minutes at 160-350 degreeC.

  The application method of the non-chromate primer and the top coat is not particularly limited, and a commonly used dipping method, spray method, roll coat method, air spray method, airless spray method and the like can be used.

Examples of the present invention and comparative examples are given below to specifically describe the present invention.
1. Preparation of test plate 1.1 Test material, electrogalvanized steel sheet (hereinafter symbol: EG)
Plate thickness 0.6mm, plating coverage 20g / m ² per side (double-sided plating)
・ Hot galvanized steel sheet (hereinafter symbol: GI)
Plate thickness 0.6mm, zinc adhesion amount 50g / m ² per one side (double-sided plating)
・ Aluminum-zinc alloy plated steel sheet (hereinafter symbol: GL)
Plate thickness 0.6mm, plating coverage 50g / m ² per side (double-sided plating)

1.2 Pretreatment CL-N364S (manufactured by Nihon Parkerizing Co., Ltd.), which is an alkaline degreasing agent, is used as an aqueous solution having a concentration of 20 g / L and a temperature of 60 ° C. Washed with water and dried.

1.3 Surface Treatment / Examples 1 to 12, Comparative Examples 1 to 4
On the surface (one side) of the test material after pretreatment, the surface treatment agent having the composition shown in Table 1 and Table 2 was applied using a roll coater so that the dry film amount was 0.1 g / m ² . Drying was performed in a hot air drying furnace under the condition of a reaching plate temperature of 80 ° C.
・ Coating chromate treatment (Comparative Examples 5 and 6)
ZM-1300AN (manufactured by Nihon Parkerizing Co., Ltd.), which is a coating type chromate agent, is applied to the surface (one side) of the test material after pretreatment using a roll coater, and the Cr adhesion amount is 40 mg / m ² . It was applied so that it was dried in a hot air drying oven under the condition of a reaching plate temperature of 80 ° C.

1.4 Application of undercoat and topcoat The primer and topcoat were applied in the following two combinations on the treated surface of each surface-treated plate prepared in 1.3.
<Upper layer A>: After applying a commercially available primer paint (Dai Nippon Paint Co., Ltd., V Knit # 200) (dry film thickness 5.5 μm), baking at 200 ° C., then top coat paint on the baking surface (Dai Nippon Paint Co., Ltd., V knit # 500) was applied (dry film thickness 17 μm), and baked at 220 ° C. to prepare a test plate.
<Upper layer B>: A commercially available primer coating (Nippon Paint Co., Ltd., Flexcoat 600) was applied (dry film thickness: 5.0 μm), then baked at 200 ° C., and then a top coat coating (Japan) Paint Co., Ltd., Flexcoat 5030) was applied (dry film thickness 15 μm), and baked at 225 ° C. to prepare a test plate.

2. Evaluation Test 2.1 Corrosion Resistance The coating film of each test plate produced was scratched with a cutter to reach a metal substrate, and a salt spray test specified in JIS-Z2371 was performed for 480 hours. The criterion for determination was the film swelling width (maximum value on one side) from the cut part. Moreover, the end surface corrosion resistance measured the coating film swelling width (maximum value) from the end surface.
<Evaluation criteria-Cut part>
A: Less than 2 mm B: 2 mm or more and less than 5 mm Δ: 5 mm or more and less than 10 mm x: 10 mm or more <Evaluation Criteria—End Face>
◎: Less than 4 mm ○: 4 mm or more and less than 8 mm Δ: 8 mm or more and less than 12 mm x: 12 mm or more

2.2 Bending adhesion test 2.2.1 Primary bending adhesion test (coating primary adhesion)
In accordance with the test method of JIS-G3312, a 2T bending test with two inner spacing plates was performed at 20 ° C. for each test plate, and the peeling state of the coating film after peeling the tape was observed with the naked eye. The coating adhesion was evaluated according to the judgment criteria.
<Evaluation criteria>
◎: No peeling ○: Peeling area less than 10% □: Peeling area 10% or more and less than 50% Δ: Peeling area 50% or more and less than 80% ×: Peeling area 80% or more

2.2.2 Secondary bending adhesion (painting secondary adhesion)
The test plate was immersed in boiling water for 2 hours and then allowed to stand for one day, and then the same test as the primary bending adhesion test was performed. Judgment criteria are as follows.
<Evaluation criteria>
◎: No peeling ○: Peeling area less than 10% □: Peeling area 10% or more and less than 50% Δ: Peeling area 50% or more and less than 80% ×: Peeling area 80% or more

2.3 Coin scratch resistance A 10-yen coin was installed at an angle of 45 ° with respect to each test plate, the coating film was rubbed at a constant speed with a load of 3 kg, and the degree of scratching of the coating film was observed with the naked eye. Coin scratch resistance was evaluated according to the criteria. In addition, in the following evaluation, the part where the primer was exposed by peeling off only the top coat was not included in the exposed area of the substrate as scratches not caused by the base treatment film.
<Evaluation criteria>
◎: 0% of substrate exposure (including the case where only the primer is exposed)
○: Substrate exposure is less than 10% □: Substrate exposure is 10% or more and less than 50% △: Substrate exposure is 50% or more and less than 80% ×: Substrate exposure is 80% or more

3. Evaluation results Table 2 shows the results of the evaluation tests. Examples 1 to 18 in Table 2 are painted plate performances of a metal material formed by coating the aqueous surface treatment agent of the present invention (Nos. 1 to 8 in Table 1) and then forming a film. Corrosion resistance of cut part and end surface), primary adhesion of coating, secondary adhesion of coating, and coin scratch properties are all good, showing the same or better performance than the chromate treatment of Comparative Examples 5 and 6. It was.
In addition, when a silane coupling agent having an amino functional group is used, the coating adhesion is excellent as compared with the case of using a silane coupling agent having a glycidyl group (Examples 5 and 6 and Examples respectively). 7 and 8), and when a silane coupling agent having an amino functional group is used, it is less affected by the compatibility with the primer than when a silane coupling agent having a glycidyl group is used. Yes (comprehensive judgment of the above two comparisons). Further, when a silane coupling agent having a primary amino group or a secondary amino group and a silane coupling agent having a glycidyl group are used in combination, the end face corrosion resistance is particularly excellent as compared with the case where only the former is used. (Comparison between Examples 10, 11, 12, and 13 and Examples 5, 6, 2, and 3, respectively).
On the other hand, No. 1 in Table 1, which is outside the scope of the present invention. 9 (no vanadium-containing compound (B) or tungsten-containing compound (B) used), 10 (the amount of vanadium-containing compound (B) used relative to the silane coupling agent (A) is outside the scope of the present invention) and 11 (silane coupling) In Comparative Examples 1 to 4 of Table 2 using the aqueous surface treatment agent (agent (A) not used), the corrosion resistance (cut portion and end surface corrosion resistance), coating primary adhesion, coating secondary adhesion, coin scratch resistance At least two were inferior.

Note) V-containing compound: vanadium oxyacetylacetonate (IV)
W-containing compound: ammonium metatungstate (VI)
Water-dispersible silica: The liquid phase silica uses Snowtex N manufactured by Nissan Chemical Industries.
Gas phase silica uses Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.
The medium is all water and the total solid content is all 10% by weight. Moreover, mass ratio is solid content mass ratio.
* 1: No. In No. 11, the W-containing compound was used in an amount 1/10 times that of gas-phase silica on a solid basis.

Claims (7)

The silane coupling agent (A), the vanadium-containing compound and / or the tungsten-containing compound (B) are 0.1 / 100 to 40 / as a solid content mass ratio of vanadium atoms and / or tungsten atoms / (A). An aqueous surface treating agent for environment-friendly pre-coated metal materials, contained in the range of 100. The aqueous surface treating agent according to claim 1, wherein 0.2 mass% or more of the entire silane coupling agent (A) is a silane coupling agent having an amino functional group as a solid content standard. The silane coupling agent (A) comprises a silane coupling agent having a primary amino group or a secondary amino group and a silane coupling agent having a functional group capable of reacting with the amino group, the former: the equivalent ratio of the latter The aqueous surface treating agent according to claim 1 or 2, wherein is from 50: 1 to 1:50. The aqueous surface treating agent according to claim 3, wherein the silane coupling agent having a functional group capable of reacting with an amino group is a silane coupling agent having an epoxy group bonded to an adjacent carbon atom. Furthermore, the water system of any one of Claims 1-4 which contains water dispersible silica (C) in the range of 1/50-10/1 as solid content mass ratio of (C) / (A). Surface treatment agent. Corresponding to the environment characterized in that the water-based surface treatment agent according to any one of claims 1 to 5 is applied to the surface of the metal material and then dried to form a dry film of 0.01 to 1 g / m ^2. Surface treatment method for a finished metal material. A method for producing an environment-friendly pre-coated metal material, wherein the metal material surface-treated by the surface treatment method according to claim 6 is further coated with an upper layer coating not containing chromium.