KR20090077947A - Aqueous surface treatment for environment-friendly precoated metal materials, surface-treated metal materials, and environment-friendly precoated metal materials - Google Patents

Abstract

[PROBLEMS] To provide a chromium-free aqueous surface treatment useful as primer in producing precoated metal materials which are excellent in corrosion resistance, tight adhesion of coat (primary adhesiveness and secondary adhesiveness of coat in T-bend test), and coin scratch resistance. [MEANS FOR SOLVING PROBLEMS] An aqueous surface treatment for environment-friendly precoated metal materials which contains (A) a silane coupling agent and/or a condensate of a silane coupling agent, (B) a metal oxide sol, (C) a metal compound, and (D) water-dispersible silica, wherein the metal compound (C) is at least one member selected from among compounds of V, W, Mo, Al, Sn, Nb, Hf, Y, Ho, Bi, La, Ce and Zn, and the (B)/(A) mass ratio is 1/50 to 10/1, the (C)/(A) mass ratio is 1/1000 to 4/10, and the (D)/(A) mass ratio is 1/50 to 10/1; and metal materials and chromium-free precoated metal materials, which have films made from the surface treatment.

Description

Aqueous surface treatments for environmentally friendly precoated metal materials and surface treated metal materials and environmentally friendly precoated metal materials }

The present invention relates to a non-chromic water-based surface treatment agent useful as a ground treatment agent for producing a precoating metal material excellent in paint adhesion, corrosion resistance, and coin scratch resistance, and a surface treatment metal material and an environmentally compatible precoating metal material.

Conventional post-painting products coated on parts such as home appliances, building materials, automobiles, etc. after processing have been mostly pretreated with phosphates. Recently, particularly for home appliances, colored organic matters are substituted for such pretreatment. Precoated metal sheets coated with a coating have been used. This metal plate coat | covers an organic film to the metal plate and plated metal plate which carried out the base process, has the characteristic that it has workability, and corrosion resistance is favorable, having a beautiful appearance.

For example, Patent Document 1 discloses a pre-coated steel sheet in which cross-sectional corrosion resistance is improved by applying a specific chromate treatment liquid and drying it without washing with water. The precoated steel sheet subjected to such a base treatment containing chromium has workability and paint adhesion along with corrosion resistance due to the combined effect of chromate treatment and organic coating, eliminating coating after processing, and improving productivity and improving quality. Currently, it is used universally. However, due to the toxicity problem of hexavalent chromium which may elute from an organic film containing a chromate treated film and a chromium-based rust preventive pigment, in recent years, there has been a growing demand for a non-chromium rust preventive treatment and a non-chromium organic film.

The first characteristic required for the undertreatment of the precoated steel sheet is paint adhesion, and it is required to be in good contact with both interfaces, such as the underlayer metal as the lower layer and the primer as the upper layer. This coating adhesiveness may be evaluated after being immersed in boiling water for a predetermined time, which is specifically called coating secondary adhesiveness, and is distinguished from coating primary adhesiveness, which is coating adhesiveness before being immersed in boiling water. Both of these primary and secondary adhesiveness are very important characteristics which are essential for the precoated steel sheet on the premise that it will be processed into a complicated shape by post-processing. The T bending test is a very strict test and is used to evaluate the adhesion of precoated steel sheets.

Coin scratch resistance is mentioned as a 2nd characteristic calculated | required by the base treatment of a precoated steel plate. This is a characteristic that affects not only the adhesiveness but also the film hardness of the substrate treatment.

Corrosion resistance is mentioned as a 3rd characteristic calculated | required by the base treatment of a precoated steel plate. In the case of a pre-coated steel sheet, the base treatment, the primer coating treatment, and the top coating coating treatment are usually performed on the steel sheet in order. In the case of the pre-coated steel sheet subjected to the conventional chromate treatment, not only the base treatment layer but also the primer layer contains chromate. In particular, the primer layer, which is thickly used at a thickness of 3 to 10 µm, contains a large amount of chromium as a rust preventive pigment and plays a major role in imparting corrosion resistance to a precoated steel sheet, in comparison with an undertreatment which is not normally used in excess of 0.5 µm. have. By the way, the primer in the precoat steel plate which does not contain chromium can provide only the corrosion resistance which hardly falls below the primer containing a chromium system antirust pigment. Therefore, in the pre-coated steel sheet of a non-chromate, the base treatment part can be said to play the role of providing corrosion resistance rather than the conventional chromate system.

Patent Document 2 discloses a technique for improving white rust resistance and paint adhesion by surface-treating zinc and zinc alloys with an aqueous solution containing tannic acid and a silane coupling agent as a non-chromium-based antirust treatment method instead of chromate treatment. However, this method cannot sufficiently secure the scratch resistance and corrosion resistance required for the precoated metal sheet. Patent Document 3 discloses forming a chemical conversion film containing a binder such as silica fine particles and polyacrylic acid on the surface of a galvanized steel sheet. However, in this method, the coating adhesiveness and corrosion resistance required for the precoated steel sheet do not fall short of those obtained by chromate treatment.

Patent Document 4 discloses a technique of imparting primary rust resistance by surface treatment of a 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 converted to a precoated steel sheet, the performance as a coating base on the precoated steel sheet, which requires strict adhesion, is not sufficient. The adhesiveness achieved by the treatment liquid for provision of temporary rust prevention property is the work adhesiveness of the erikxen extrusion level, and the work adhesiveness of the level which will pass the T bending test is not achieved. Similarly, even when the anti-fingerprint agent and the lubricating agent are converted to the base treatment agent of the precoated steel sheet, they cannot withstand the strict T-bending adhesion test.

Patent Literature 5 describes a technique of base treatment in a precoated steel sheet in which the surface of the coated steel sheet is treated with an aqueous solution containing a 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. Is disclosed. The inhibitor action by the thiocarbonyl group-containing compound and phosphoric acid is insufficient, and it does not reach the chromate-treated precoated steel sheet in terms of corrosion resistance as a precoated steel sheet, particularly in terms of corrosion resistance of the cross section.

Patent Literature 6 describes a method in which a steel is immersed in a treatment hot bath containing a silane coupling agent and ammonium molybdate, but then washed with water to form a reaction treated base film and subjected to anticorrosion coating as an upper layer. A method for producing a coated steel is disclosed. This technique is not applicable to precoated steel sheets because it requires dipping and washing processes. Patent Document 7 discloses a surface of a coated steel sheet such as a galvanized steel sheet such as aluminum salts, boron compounds, metal salts other than aluminum, and SiO ₂ , SnO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , MgO, Al ₂ O. Disclosed is a technique of treating at least one of sol or powder of ₃ , ZrO ₂ and Sb ₂ O ₅ with a liquid dissolved or dispersed in water to impart corrosion resistance and paint adhesion. However, even with this technique, the paint adhesion in the precoated steel sheet cannot be tolerated.

Patent Document 1: Japanese Patent Application Laid-Open No. 3-100180

Patent Document 2: Japanese Patent Application Laid-Open No. 59-116381

Patent Document 3: Japanese Unexamined Patent Publication No. 2002-80979

Patent Document 4: Japanese Unexamined Patent Publication No. 2001-164195

Patent Document 5: Japanese Patent Application Laid-Open No. 2001-316845

Patent Document 6: Japanese Unexamined Patent Publication No. 2003-34881

Patent Document 7: JP 2005-256156 A

The present invention is a water-based 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 environmentally non-chromium-based, and a surface-treated metal obtained by using the same. An object of the present invention is to provide an environmentally compatible precoated metal material having excellent material and paint adhesion, corrosion resistance, and coin scratch resistance.

The problem is,

(1) A silane coupling agent (A), a metal oxide sol (B), a metal compound (C) and a water dispersible silica (D) are contained, and a metal compound (C) is a V compound, a W compound, a Mo compound, and an Al compound , Sn compound, Nb compound, Hf compound, Y compound, Ho compound, Bi compound, La compound, Ce compound and Zn compound are at least one selected from the group, and the ratio of component (A) and component (B) is (B) It is the range of 1 / 50-10 / 1 as solid content mass ratio of / (A), and ratio of component (A) and component (C) is 1/1000-4/10 of solid content mass ratio of (C) / (A) Water-based surface treatment agent for environmentally-friendly precoat metal materials in the range and whose ratio of component (A) and component (D) is the range of 1 / 50-10 / 1 as solid content mass ratio of (D) / (A);

(2) The metal oxide sol (B) is composed of zirconium oxide sol, cerium oxide sol, aluminum oxide sol, tin oxide sol, niobium oxide sol, zinc oxide sol, antimony oxide sol, bismuth oxide sol, yttrium sol and holmium oxide sol. The aqueous surface treating agent of said (1) which is at least 1 sort (s) chosen;

(3) The aqueous surface treatment agent of the above (1) or (2), wherein at least 5% by mass of the silane coupling agent (A) is a silane coupling agent having an amino functional group;

(4) The above (1), wherein the silane coupling agent (A) is a mixture of an equivalent ratio of 50: 1 to 1: 50 of the silane coupling agent containing an amino functional group and a silane coupling agent having an epoxy group bonded to a neighboring carbon atom; or (2) the aqueous surface treating agent;

(5) The metal material which has a dry film of 0.01-1 g / m <2> on the surface as a dry film from the water-based surface treatment agent in any one of said (1)-(4); And

(6) It is achieved by the environment-adaptive pre-coated steel sheet which formed the upper layer film which does not contain chromium further on the surface of the metal material of said (5).

Although the coating layer does not contain chromium, the precoat metal material obtained by giving the upper layer coating which does not contain chromium to the metal material processed with the water-based surface treatment agent for environmentally-friendly precoat metal materials of this invention further contains chromium, It is excellent in corrosion resistance, coating adhesion (painting primary adhesion and painting secondary adhesion after the T bending test) and coin scratch resistance. Therefore, this invention is an invention with very high industrial value. The precoated metal material of the present invention is also excellent in moisture resistance and chemical resistance (alkali resistance and acid resistance).

This invention is demonstrated in detail below.

The aqueous surface treatment agent of this invention is a silane coupling agent (A), a metal oxide sol (B), and a V compound, W compound, Mo compound, Al compound, Sn compound, Nb compound, Hf compound, Y compound, Ho compound, Bi It is characterized by containing at least 1 type of metal compound (C) chosen from a compound, a La compound, a Ce compound, and a Zn compound, and water-dispersible silica (D) in a specific mutual ratio.

The silane coupling agent (A) has a high -OH activity of the silanol group produced by hydrolysis, and has a strong chemical bond of -Si-O-M via a base metal M and an oxygen atom as the base material. This chemical bond especially contributes to good adhesion with the underlying metal. Moreover, it may also contribute to the improvement of adhesiveness with an upper layer by reaction with the organic functional group contained in an upper layer. When the polar group which has the polarity O, N, etc. as a component was introduce | transduced as a functional group of a silane coupling agent, adhesiveness with an upper layer further improves.

As the silane coupling agent applicable to the present invention, for example, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (Aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxy silane, N-phenyl γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxy Propyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl ) -γ-aminopropylmethyldimethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyl Triethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimeth Oxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriacetoxysilane , γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropylmethyldiethoxysilane, hexamethyldisilazane, γ-anilinopropyltrime Oxysilane, 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- (Methyl diethoxysilyl) propyl] ammonium chloride, (gamma)-chloropropylmethyl dimethoxysilane, (gamma)-mercaptopropylmethyldimethoxysilane, methyl trichlorosilane, dimethyldichlorosilane, a trimethylchlorosilane, etc. are mentioned. Only 1 component of these can be used, or can be used in combination.

In most cases, the base treatment agent has a phase compatibility with a primer to be applied to the upper layer slightly, and the performance may not be as expected depending on the combination. What has an amino functional group in the said coupling agent is hard to depend on upper phase with upper layer. Therefore, in the aqueous surface treatment agent (base treatment agent) of this invention, it is preferable that a silane coupling agent (A) contains at least 1 sort (s) which has an amino functional group. Here, in this invention, an amino functional group shall mean at least 1 sort (s) of functional group chosen from a primary amino group and a secondary amino group. The amino functional group has a relatively high reaction activity in either the acidic medium or the basic medium. That is, in the organic functional group which generally has active hydrogen, although it also differs according to the acid basic of a solution and the substituent adjacent to a functional group, an amino functional group has comparatively high reactivity (nucleophilic and basic). Since the amino functional group has high reactivity, the silane coupling agent which has an amino functional group reacts with the functional group (ester group, epoxy group, etc.) of resin which comprises the primer of an upper layer, and expresses favorable coating adhesiveness. As a composite effect of the effect that this coating adhesiveness improves compared with another silane coupling agent, water resistance, chemical resistance (alkali, acid), moisture resistance, etc. may be improved. It is preferable to have one amino functional group in 1 molecule of a silane coupling agent among the silane coupling agents which have an amino functional group. It is preferable that it is 5 mass% or more as solid content basis, and, as for the usage-amount with respect to the whole silane coupling agent (A) of the silane coupling agent which has an amino functional group, from a viewpoint of expressing higher coating adhesiveness, it is more preferable that it is 10 mass% or more. It is further more preferable that it is 20 mass% or more.

When using 2 or more types as a silane coupling agent (A), the functional group which can react with the silane coupling agent which has an amino functional group, and an amino functional group, for example, an epoxy group couple | bonded with the adjacent carbon atom (glycidyl group, It is preferable to use a silane coupling agent having a 3,4-epoxycyclohexyl group or the like). The use ratio of these silane coupling agents does not need to be an amount which mutual functional groups react without excess or deficiency, and is an equivalent ratio of the silane coupling agent which has an amino functional group, and the functional group which can react with an amino functional group, and is 50: 1-1: 1: It is preferable that it is the range of 50, It is more preferable that it is the range of 10: 1-1:10, It is used in combination with the silane coupling agent which has the silane coupling agent which has an amino functional group, and the epoxy group couple | bonded with the adjacent carbon atom. In the case, in addition to the effect on the said coating adhesiveness by the silane coupling agent which has an amino functional group, corrosion resistance can be improved further.

In addition, when using a some silane coupling agent, what is necessary is just to mix, and to mix with another component.

The aqueous surface treatment agent of this invention contains a metal oxide sol (B). The metal oxide sol (B) contributes to the improvement of adhesion in that the polar group is introduced. However, excessive addition may make penetration of water into the interface easy, and the coating secondary adhesiveness may fall. In addition, the metal oxide sol (B) increases the hardness of the base film and contributes to the improvement of the coating adhesion, and thus also acts effectively to improve the coin scratch resistance. In addition, the metal oxide sol (B) works effectively to improve chemical resistance, and in particular, to effectively improve alkali resistance.

As the metal oxide sol, at least one species selected from zirconium oxide sol, cerium oxide sol, aluminum oxide sol, tin oxide sol, niobium oxide, zinc oxide sol, antimony oxide sol, bismuth oxide sol, yttrium sol and holmium sol Preferably, more specifically, ZrO ₂ sol (zirconia sol), TiO ₂ sol (titania sol), CeO ₂ sol, Al ₂ O ₃ sol (alumina sol), SnO ₂ sol, NbO sol, ZnO sol, Sb ₂ O ₅ sol, and the like Bi ₂ O ₃ sol, Y ₂ O ₃ sol, Ho ₂ O ₃ sol.

It is preferable that it is 1-1000 nm, as for the particle diameter of the metal oxide sol particle used for this invention, it is more preferable that it is 1 nm-500 nm, It is further more preferable that it is 1 nm-100 nm. These metal oxide particles may be secondary agglomerated or tertiary agglomerated to have a secondary particle diameter or a tertiary particle diameter. However, the metal oxide particles may be stably dispersed in water even when aggregated. If the primary particle size is less than 1 nm, the treatment agent stability deteriorates, such as thixotropy. Moreover, when it exceeds 1000 nm, bending adhesiveness will deteriorate.

Content of a metal oxide sol (B) needs to be the range of 1 / 50-10 / 1 as solid content mass ratio of (B) / (A) with respect to a silane coupling agent (A), 1 / 30-4 / It is preferable that it is the range of 1, and it is more preferable that it is the range of 1/10-2/1. When the said content is less than 1/50, there exists a tendency for chemical resistance and corrosion resistance to fall, and when it exceeds 10/1, there exists a tendency for chemical resistance to fall.

As a commercial item of the metal oxide sol (B) used for this invention, as a zirconia sol, nano use ZR40BL, nano use ZR30BS, nano use ZR30BH, nano use ZR30AL, nano use ZR30AH (made by Nissan Chemical Co., Ltd.), ZSL-20N , ZSL-10T, ZSL-10A (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd.), YSL-10 (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd.) as yttrium sol; Co., Ltd.), SBSL-50 (made by Daiichi Rare Element Chemical Industry Co., Ltd.) as antimony sol, CESL-15N (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd.) as cerium sol, Nanotek Bi ₂ O ₃ as bismuth sol (Manufactured by CI Hwasung Co., Ltd.), Nanotek Ho ₂ O ₃ (manufactured by CI Hwasung Co., Ltd.) as a poronium sol, Nanotek TiO ₂ (manufactured by CI Hwaseong Co., Ltd.) as a titania sol, Nanotek ZnO (CI Hwaseong ( Alumina sol 100, alumina sol 200, alumina sol 520 (manufactured by Nissan Chemical Co., Ltd.), NanoTek Al ₂ O ₃ (manufactured by CI Chemicals Co., Ltd.) and the like.

The aqueous surface treatment agent of this invention contains a metal compound (C). The metal compound (C) is at least one selected from V compound, W compound, Mo compound, Al compound, Sn compound, Nb compound, Hf compound, Y compound, Ho compound, Bi compound, La compound, Ce compound and Zn compound to be. The metal compound (C) acts as an inhibitor (corrosion inhibiting substance) and improves corrosion resistance. Although the mechanism for improving the corrosion resistance of a metal compound (C) is not clear, the point which acquires some mantissa is a point. Moreover, when there is no change in valence, the presence form as a heteropoly acid may be acquired by the change of pH. The heteropolyacid may denature the action conventionally possessed by physical or chemical action on the silane coupling agent (A) or the metal oxide sol (B) in the surface treatment agent. Therefore, chemical resistance, moisture resistance, etc. may be improved in addition to improving corrosion resistance.

Examples of the metal compound (C) include carbonates, oxides, hydroxides, nitrates, sulfates, phosphates, fluorides, fluoroacids or salts thereof, oxoacid salts and organic acid salts of the above metals. In the case where the metal compound (C) is an oxide, the sol form is excluded.

As a specific compound, V compounds include vanadium pentoxide (V), vanadium trioxide (III), vanadium dioxide (IV), vanadium hydroxide (II), vanadium hydroxide (III), vanadium sulfate (II), and vanadium sulfate (III) ), Vanadium oxysulphate (IV), vanadium fluoride (III), vanadium fluoride (IV), vanadium fluoride (V), oxy trivanadium chloride VOCl ₃ , vanadium chloride VCl ₃ , hexafluorovanadium acid (III) or its Salts (potassium salt, ammonium salt, etc.), metavanadium acid (V) or salts thereof (sodium salt, ammonium salt, etc.), vanadilacetylacetonate (IV) VO (OC (= CH ₂ ) CH ₂ COCH ₃ ) ₂ , vanadium Acetylacetonate (III) V (OC (= CH ₂ ) CH ₂ COCH ₃ ) ₃ , invanad molybdate H _15-X [PV _12-X MoO ₄₀ ] .nH ₂₀ (6 <X <12, n <30 ), And the like.

W compounds include tungsten oxide (IV), tungsten oxide (V), tungsten oxide (VI), tungsten fluoride (IV), tungsten fluoride (VI), tungsten fluoride (VI) H ₂ WO ₄ or salts thereof (ammonium salt, sodium Salts, etc.), metatungstic acid (VI) H ₆ [H ₂ W ₁₂ O ₄₀ ] or salts thereof (ammonium salt, sodium salt, etc.), paratungstic acid (VI) H ₁₀ [W ₁₂ O ₄₆ H ₁₀ ] or salts thereof (Ammonium salt, sodium salt, etc.) etc. are mentioned.

Examples of Mo compounds include invanad molybdate H _15-X [PV _12-X MoO ₄₀ ] .nH ₂₀ (6 <X <12, n <30), molybdenum oxide, molybdate H ₂ MoO ₄ , ammonium molybdate, para Ammonium molybdate, sodium molybdate, molybdate phosphate compound (e.g. ammonium molybdate phosphate (NH ₄ ) ₃ [PO ₄ Mo ₁₂ O ₃₆ ] .3H ₂ O, sodium molybdate phosphate Na ₃ [PO ₄ Mo ₁₂ O ₃₆ ] .nH ₂ O and the like.

Examples of Al compounds include aluminum nitrate, aluminum sulfate, potassium sulfate, sodium aluminum sulfate, ammonium sulfate, aluminum phosphate, aluminum carbonate, aluminum oxide, aluminum hydroxide, and the like; Examples of the Sn compound include tin oxide (IV), sodium stannate Na ₂ SnO ₃ , tin chloride (II), tin chloride (IV), tin nitrate (II), tin nitrate (IV), and hexafluoroammonium (NH ₄ ) SnF ₆ etc .; Examples of the Nb compound include niobium pentaoxide (Nb ₂ O ₅ ), sodium niobate (NaNbO ₃ ), niobium fluoride (NbF ₅ ), ammonium hexafluoroniobate (NH ₄ ) and NbF ₆ .

Examples of the Hf compound, Y compound, Ho compound, Bi compound, and La compound include hafnium oxide, hexafluorohafnium hydrofluoric acid, yttrium oxide, yttrium acetylacetonate, holmium oxide, bismuth oxide, and lanthanum oxide.

Ce compounds include cerium oxide, cerium acetate Ce (CH ₃ CO ₂ ) ₃ , cerium nitrate (III) or (IV), cerium ammonium nitrate, cerium sulfate, cerium chloride and the like; Examples of the Zn compound include zinc oxide, zinc hydroxide, zinc acetate, zinc nitrate, zinc sulfate, zinc chloride, sodium zincate and the like.

Content of a metal compound (C) needs to be the range of 1 / 1000-4 / 10 as solid content mass ratio of (C) / (A) with respect to a silane coupling agent (A), It is preferable that it is a range, and it is more preferable that it is a range of 1/100-1/10. When the said content is less than 1/1000, a corrosion resistance improvement effect does not generate | occur | produce, and when it exceeds 4/10, depending on the kind of primer apply | coated to an upper layer, especially the fall of coating secondary adhesiveness may be caused. have.

Moreover, in the case where the liquid stability of a processing agent worsens by addition of a metal compound (C), liquid stability by adding suitably carboxylic acid, such as an acetic acid, a propionic acid, an oxalic acid, gluconic acid, tartaric acid, malic acid, ascorbic acid, a tannic acid, suitably Can improve.

The aqueous surface treatment agent of this invention contains water-dispersible silica (D). Water-dispersible silica (D) contributes to the improvement of adhesiveness in that it introduces a polar group. However, excessive addition also makes it easy to penetrate into a water interface, and the coating secondary adhesiveness may fall. In addition, the water-dispersible silica (D) increases the hardness of the base film and contributes to the improvement of coating adhesion, and thus acts effectively on improving the coin scratch resistance.

The water-dispersible silica (D) includes gaseous silica produced by a gas phase reaction and liquid silica produced in a state dispersed in water by a liquid phase reaction, both of which can be used.

It is preferable that it is 1-100 nm, and, as for the particle diameter of the water dispersible silica (D) used for this invention, it is more preferable that it is 2 nm-50 nm. These water-dispersible silicas (D) may be secondary agglomerated or tertiary agglomerated to have secondary particle diameters and tertiary particle diameters, but they may be stably dispersed in water even if they are agglomerated. If the primary particle size is less than 1 nm, the treatment agent stability deteriorates, such as thixotropy. Moreover, when it exceeds 100 nm, bending adhesiveness will deteriorate.

Content of water-dispersible silica (D) needs to be the range of 1 / 50-10 / 1 as solid content mass ratio of (D) / (A) with respect to a silane coupling agent (A), and 1 / 30-4 / 1 It is preferable that it is the range of, and it is more preferable that it is the range of 1/10-2/1. When the said content is less than 1/50, there exists a tendency for coating adhesiveness and the coin scratch resistance to fall, and when it exceeds 10/1, there exists a tendency for chemical resistance to fall.

Commercially available products of the water-dispersible silica (D) used in the present invention as liquid silica, Snowtex C, Snowtex O, Snowtex N, Snowtex NXS, Snowtex OS, Snowtex OUP, Snowtex OL, Snowtex PS- MO, Snowtex PS-S, Snowtex S, Snowtex UP, Snowtex PS-M, Snowtex PS-L, Snowtex 20, Snowtex 30, Snowtex 40 (all manufactured by Nissan Chemical Industries, Ltd.), etc. ; As vapor phase silica, Aerosil 50, Aerosil 130, Aerosil 200, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil MOX80, Aerosil MOX170 (All are manufactured by Japan Aerosol Co., Ltd.). Only 1 component of these can be used, or can be used in combination.

You may add an acid or a base to water-dispersible silica (D) used by this invention suitably from a viewpoint of dispersion stability. As an acid, any of an inorganic acid and an organic acid may be sufficient, for example, hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, etc. are mentioned. Examples of the base include sodium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, and the like.

It is preferable that it is 3-10, and, as for pH of the aqueous surface treating agent of this invention, it is more preferable that it is 5-9. When using the silane coupling agent (A) which has an amino functional group especially, it is preferable that the pH is 7-9.

In the aqueous surface treatment agent of the present invention, in order to control the pH of the treatment agent, an appropriate acid (for example, acetic acid, phosphoric acid, etc.) or an alkali (for example, ammonia, organic amine, etc.) may be added.

The aqueous surface treatment agent of the present invention includes a water-soluble resin for softening the treated film, a surfactant called an oil-based enhancer for obtaining a uniform film on the surface, a thickener, a conductive material for improving weldability, a coloring pigment for improving the designability, and the like. You may contain it.

The medium of the aqueous surface treating agent of the present invention is water. Although there is no restriction | limiting in particular about the total solid content concentration in the aqueous surface treating agent of this invention, It is preferable that total solid content concentration is about 1-20 mass% in consideration of coating film formation property and operability.

The water-based surface treatment agent of the present invention is prepared by adding a silane coupling agent (A), a metal oxide sol (B), a metal compound (C) and a water dispersible silica (D), and other additives, if used, to water and stirring. 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 sheets, hot rolled steel sheets, hot dip galvanized steel sheets, electrogalvanized steel sheets, hot dip galvanized steel sheets, aluminum plated steel sheets, aluminum-zinc alloy plated steel sheets, and stainless steel sheets. Metal materials including generally known metal plates such as steel sheets, aluminum plates, copper plates, titanium plates, magnesium plates, and other plated metal plates can be used.

Prior to applying the water-based surface treatment agent of the present invention to the metal material, the metal material may optionally be subjected to conventional treatment such as hot water washing, alkali degreasing, surface adjustment, and the like.

The aqueous surface treatment agent of the present invention can be applied to metallic materials by conventional coating methods such as roll coating, curtain flow coating, air spray, airless spray, dipping, bar coating, brush coating, and the like. Although drying after application | coating, there is no restriction | limiting in particular in a drying method, drying temperature, and drying time, It does not matter if it is the temperature and time which water evaporates. For example, what is necessary is just to make the highest achieved temperature of metal materials, such as a metal plate apply | coated in oven, 60-120 degreeC, and to dry.

The coating amount of the aqueous surface treatment agent of the present invention needs to be in the range of 0.01 to 1 g / m 2 as the dry coating amount, preferably in the range of 0.02 to 0.4 g / m 2, and more preferably in the range of 0.05 to 0.2 g / m 2. Do. When the amount of the coating is less than 0.01 g / m 2, the amount of the coating is too small, so that variation in the amount of coating due to the site tends to occur, and the adhesion (adhesion to the metal material and the upper layer) tends to be insufficient. Moreover, when coating amount exceeds 1 g / m <2>, there exists a tendency for coating adhesiveness to become inadequate and it becomes disadvantageous in terms of cost.

The treatment with the water-based surface treatment agent of the present invention is usually carried out as a base treatment in a precoated metal material as described below, and may also be carried out as a base treatment in a laminated steel sheet.

The invention also relates to a precoated metal material. The precoated metal material of this invention can be obtained by forming the upper coating layer which does not contain chromium on the film formed by apply | coating and drying the water-based surface treating agent of this invention to a metal material. The upper coating layer is usually composed of a bichromate primer layer and a top coating layer formed thereon (the top coating layer does not usually contain chromium). The upper coating layer is formed by applying and drying the aqueous surface treatment agent of the present invention. On the coated film, the bichromate primer can be formed by coating and drying, followed by applying a top coat thereon. In addition, the upper coating layer may consist only of the top coating layer. In this case, the upper coating layer can be formed by applying the top coating onto the coating formed by applying and drying the aqueous surface treatment agent of the present invention.

As the non-chromate primer that can be used in the present invention, any primer can be used as long as the primer does not use a chromate-based anti-rust pigment during the mixing of the primer. The base resin of the bichromate primer may be in any form of an aqueous system, a solvent system, a powder system, or the like. As the type of resin, generally known ones, for example, polyacrylic resin, polyolefin resin, polyurethane resin, epoxy resin, polyester resin, polybutyral resin, melamine resin or the like can be used as it is or in combination. Can be. Examples of the anti-rust pigments include those generally known, for example, (1) phosphate-based anti-rust pigments such as zinc phosphate, iron phosphate and aluminum phosphate, (2) molybdenum such as calcium molybdate, ammonium molybdate and barium molybdate Acid type antirust pigment, (3) Vanadium type antirust pigments, such as vanadium oxide, (4) Fine silica, such as water-dispersible silica and fumed silica, etc. can be used. About the compounding quantity on the solid content basis of each component with respect to the whole bichromate primer, it is preferable that the compounding quantity on the solid content basis of the antirust pigment with respect to the whole non-chromate primer is 1-40 mass%. When the compounding quantity of an antirust pigment is less than 1 mass%, corrosion resistance is not enough, and when it exceeds 40 mass%, workability will fall.

It is preferable that the coating film thickness of a primer is 1-30 micrometers in dry film thickness. If it is less than 1 micrometer, corrosion resistance will fall, and if it exceeds 30 micrometers, the adhesiveness at the time of processing will fall. There is no restriction | limiting in particular about the baking drying conditions of the said bichromate primer, For example, it can be set as 10 second-5 minutes at 130-250 degreeC.

The top coating is not particularly limited, and any of conventional top coatings may be used. The base resin of the top coating may be in any form of an aqueous system, a solvent system, or a powder system. As the type of resin, generally known ones, for example, polyacrylic resin, polyolefin resin, polyurethane resin, epoxy resin, polyester resin, polybutyral resin, melamine resin, etc. Available.

You may mix | blend a coloring pigment with a top coating, There is no restriction | limiting in particular as a coloring pigment, Inorganic pigments, such as a titanium bag, zinc sulfur, an alumina bag, carbon black, iron group, yellow iron oxide, molybdate orange, and zirconium oxide (IV) B, organic pigments such as Hansa Yellow, pyrazolone orange, azo pigments and the like can be used. Moreover, you may mix | blend the above-mentioned antirust pigment suitably for top coating, and may also mix | blend additives, such as an antifoamer, a leveling agent, a dispersal auxiliary agent, and a diluent for reducing paint viscosity, suitably.

It is preferable that the coating film thickness of a top coating is 3-40 micrometers in dry film thickness. If it is less than 3 micrometers, corrosion resistance will fall, and if it exceeds 40 micrometers, adhesiveness will fall, and cost will become high. There is no restriction | limiting in particular about the baking drying conditions of the said top coating, For example, it can be set as 10 second-20 minutes at 160-350 degreeC.

The application method of the bichromate primer and the top coating is not particularly limited, and generally used dipping methods, spraying methods, roll coating methods, air spraying methods, airless spraying methods and the like can be used.

The present invention will be specifically described below with reference to Examples and Comparative Examples of the present invention.

1. Manufacturing of Trial

1.1 Test Materials

Electro galvanized steel plate (hereinafter symbol: EG)

  Plate thickness 0.6 mm, 20 g / m2 per plated coating weight (both sides plating)

Hot dip galvanized steel sheet (hereafter referred to as GI)

  0.6mm plate thickness, 50g / ㎡ per side of zinc adhesion amount (both sides plating)

Aluminum-zinc alloy plated steel plate (hereinafter symbol: GL)

  Plate thickness 0.6 mm, 50 g / m² per plated coating weight (both sides plating)

1.2 Pretreatment

CL-N364S (manufactured by Nippon Parkerizing Co., Ltd.), an alkali degreasing agent, was used as an aqueous solution having a concentration of 20 g / L and a temperature of 60 ° C., and the test material was immersed in this for 10 seconds, washed with pure water, and dried.

1.3 Surface Treatment

Examples 1 to 33 and Comparative Examples 1 to 18

As the surface treatment agent of the composition shown in Tables 1-3 is shown to the surface (one side) of the test material after pretreatment, as shown in Tables 4-6, a test material is selected and dry coating amount is set to 0.1 g / m <2> using a roll coater. It applied and dried under the conditions of 80 degrees C or less of plate | board temperature in a hot air drying furnace.

Coating type chromate treatment (Comparative Examples 19 and 20)

After the pretreatment, ZM-1300AN (manufactured by Nippon Parkerizing Co., Ltd.), which is a coating type chromate agent, is applied on the surface (single side) of the specimen by using a roll coater so that the Cr adhesion amount is 40 mg / m 2, and the reaching plate in the hot air drying furnace. It dried under the conditions of the temperature of 80 degreeC.

1.4 Application of Undercoat and Topcoat

On the treated surface of each surface treatment board produced in 1.3, the primer and the top coating were apply | coated by the combination of the following two methods.

<Upper layer A>: After apply | coating commercially available primer paint (Dainippon Paint Co., Ltd. make, V knit # 200) (dry film thickness of 5.5 micrometers), it bakes at 200 degreeC, and then topcoat paint further to a baking surface (Dai Nippon Coating Co., Ltd. make, V knit # 500) was apply | coated (dry film thickness 17 micrometers), and it baked at 220 degreeC, and manufactured the test board.

<Upper layer B>: After apply | coating the commercially available primer paint (Nippon Paint Co., Ltd. product, Freki Coating 600) (drying film thickness 5.0 micrometers), it bakes at 200 degreeC, and then further coats the top coating paint (on the baking surface) Nippon Paint Co., Ltd. product, Freki Coating 5030) were apply | coated (dry film thickness 15micrometer), and it baked at 225 degreeC, and manufactured the test board.

2. Evaluation test

2.1 corrosion resistance

On the coating film of each test board manufactured, the scratch which reaches the metal base with a cutter was made, and the salt spray test prescribed | regulated to JIS-Z2371 was performed for 480 hours. As a criterion of determination, the coating film expansion width (one side maximum value) from a cut part was measured. In addition, the cross-sectional corrosion resistance measured the coating film expansion width (maximum value) from a cross section.

<Evaluation criteria-cut part>

◎: less than 2 mm

○: 2 mm or more and less than 6 mm

△: 6 mm or more and less than 10 mm

× 10 mm or more

<Evaluation Criteria-Cross Section>

◎: less than 4 mm

○: 4 mm or more and less than 6 mm

□: 6mm or more and less than 8mm

△: 8 mm or more and less than 12 mm

× 12 mm or more

2.2 bending adhesion test

2.2.1 Primary Bend Adhesion Test (Paint Primary Adhesion)

According to the test method of JIS-G3312, the 2T bending test which used two inner spacer plates was performed at 20 degreeC with respect to each test board, and the peeling state of the coating film after tape peeling was observed visually, and to the following judgment criteria. Thus, the paint adhesion was evaluated.

<Evaluation Criteria>

◎: not peeled off

○: less than 10% of the peeling area

□: Peeling area 10% or more and less than 50%

(Triangle | delta): Peeling area 50% or more and less than 80%

X: Peeling area 80% or more

2.2.2 Secondary bending adhesion (painting secondary adhesion)

After immersing the test plate in non-aqueous water for 2 hours, the test plate was left for 1 day, and then the same test as in the first bending adhesion test was performed. Judgment criteria are as follows.

<Evaluation Criteria>

◎: not peeled off

○: less than 10% of the peeling area

□: Peeling area 10% or more and less than 50%

(Triangle | delta): Peeling area 50% or more and less than 80%

X: Peeling area 80% or more

2.3 Coin Scratch Resistance

A 10 yen coin was installed at an angle of 45 ° to each test plate, the coating film was rubbed at a load of 3 Kg and a constant speed, and the degree of scratching of the coating film was visually observed to evaluate coin scratch resistance according to the following criteria. . In addition, in the following evaluation, about the point which a primer was exposed by peeling only a top coat | cover, it was not included in the exposure area of a base as absorption which does not originate in a base treatment film.

<Evaluation Criteria>

(Double-circle): 0% of a subject's exposure (it includes the case where only a primer was exposed)

○: less than 10%

□: Your exposure is less than 10% and less than 50%

(Triangle | delta): 50% or more and less than 80% of your exposure

×: exposure of the body to 80% or more

2.4 Alkali Resistance

The test plate was immersed in a 5% aqueous sodium hydroxide solution at room temperature for 24 hours, and then the number of occurrences and the density of the blisters were evaluated. Judgment criteria are as follows.

◎: no blister

(Circle): One blister is 0.2 mm or less, and generation density is F, too.

□: The size of one blister is about 0.2 mm to 1 mm and the generation density is F, or the size of one blister is about 0.2 mm to 0.4 mm and the generation density is M.

(Triangle | delta): The size of one blister is about 1 mm-1.5 mm, and generation density is F, the size of one blister is about 0.4 mm-1 mm, and the generation density is M, or of one blister The size is 0.2 mm or less and the density of generation is MD.

X: The size of one blister is 1.5 mm or more, the size of a blister is 0.2 mm or more, the density of generation is MD, or the density of generation is D regardless of the size of a blister.

In addition, in the evaluation test of the said alkali resistance and the following acid resistance, F, M, MD, and D show the following meanings.

F: The number of blister generation is very small.

M: The number of blister generation is small.

MD: There are many blister occurrences.

D: The number of blisters is very large.

2.5 Acid Resistance

The test plate was immersed in a 5% aqueous sulfuric acid solution at room temperature for 24 hours, and then the number of occurrences and the density of the blisters were evaluated. Judgment criteria are as follows.

◎: no blister

(Circle): One blister is 0.2 mm or less, and generation density is F, too.

□: The size of one blister is about 0.2 mm to 1 mm and the generation density is F, or the size of one blister is about 0.2 mm to 0.4 mm and the generation density is M.

(Triangle | delta): The size of one blister is about 1 mm-1.5 mm, and generation density is F, the size of one blister is about 0.4 mm-1 mm, and the generation density is M, or of one blister The size is 0.2 mm or less and the density of generation is MD.

X: The size of one blister is 1.5 mm or more, the size of a blister is 0.2 mm or more, the density of generation is MD, or the density of generation is D regardless of the size of a blister.

2.6 Moisture Resistance

In the coating film of a test plate, the collection | absorbing which reaches metal base material was carried out with the cutter, and it was left to stand for 1000 hours in the atmosphere of 98% of humidity, and 40 degreeC of temperature. As a criterion of determination, the coating film expansion width (one side maximum value) from a cut part was measured.

◎: less than 2 mm

○: 2 mm or more and less than 4 mm

□: 4 mm or more and less than 6 mm

△: 6 mm or more and less than 10 mm

× 10 mm or more

3. Evaluation result

The result of the said evaluation test is shown to Tables 4-6. Examples 1-33 of Table 4 and 5 are the performance of the coating plate (test board) of the metal material which dried after apply | coating the aqueous surface treatment agent (N0.1-29 of Table 1) of this invention, and formed the film, and it is corrosion-resistant (Cut part and cross-sectional corrosion resistance), paint adhesion (primary and secondary after T bending test) and coin scratch resistance are all good, equivalent to or more than the case of chromate treatment of Comparative Examples 19 and 20 Performance was shown.

Moreover, when the silane coupling agent which has an amino functional group was used, compared with the case where the silane coupling agent which has an epoxy group was used, chemical resistance (alkali resistance and acid resistance) and moisture resistance were excellent (Examples 2 and 5 and Example 18). And 19). Moreover, when using together the silane coupling agent which has an amino functional group, and the silane coupling agent which has an epoxy group together, compared with the case using only the former, especially coating adhesiveness and the scratch resistance of the coin were excellent (Example 6 and Example 31- Comparison of 33).

On the other hand, N0.30 and 32 (metal oxide sol (B) and metal compound (C) not used), N0.33 and 35 (silane coupling agent (A) and metal oxide sol (B) in Table 3 outside the scope of the present invention) Unused) and in Comparative Examples 1 to 6 of Table 6 using N0.31 and 34 (metal oxide sol (B) and water dispersible silica (D) not used), the corrosion resistance (cut portion and cross-sectional corrosion resistance) At least three of paint adhesion (primary and secondary after T-bending test), coin scratch resistance, moisture resistance and chemical resistance (alkali and acid resistance) were inferior. In Comparative Examples 7, 8 and 15 to 18 using aqueous surface treatment agents of N0.36, 37 and 44 to 47 (the amount of the metal compound (C) is outside the present invention), corrosion resistance (cut portion and cross-sectional corrosion resistance), coating At least two of the adhesion (primary and secondary after T bending test), coin scratch resistance and chemical resistance (alkali resistance and acid resistance) were inferior. Moreover, in the comparative example 9 which uses the aqueous surface treating agent of N0.38 (the usage-amount of water dispersible silica (D) other than this invention), corrosion resistance (cut part and cross-sectional corrosion resistance), moisture resistance, and chemical resistance (alkali resistance and Acid resistance). Moreover, in Comparative Examples 10-14 which used the aqueous surface treating agent of N0.39-43 (the usage-amount of a metal oxide sol (D) is outside this invention), corrosion resistance (cut part and cross-sectional corrosion resistance) and chemical resistance (alkali resistance and Acid resistance).

Metal Oxide Sol (B)

Zirconia sol: Nano Youth ZR30AL (manufactured by Nissan Chemical Co., Ltd.)

Y ₂ O ₃ sol: Nanotek Y ₂ O ₃ (manufactured by CI Hwaseong Co., Ltd.)

CeO ₂ Sol: CESL-15N (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd.)

SnO ₂ sol: Daiichi Rare Element Chemical Industry Co., Ltd.

ZnO sol: Nanotek ZnO (manufactured by CI Hwaseong Co., Ltd.)

Bi ₂ O ₃ sol: Nanotek Bi ₂ O ₃ (manufactured by CI Hwaseong Co., Ltd.)

Metal compounds (C)

W: ammonium metatungstate

Mo: ammonium molybdate

Al: Aluminum Hydroxide

Ce: Cerium Oxide

V: vanadilacetylacetonate

Water Dispersible Silica (D)

Liquid Silica: Snow-Tex N (manufactured by Nissan Chemical Industries, Ltd.)

Vapor phase silica: Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.)

Claims (6)

A silane coupling agent (A), a metal oxide sol (B), a metal compound (C) and a water dispersible silica (D) are contained, and the metal compound (C) is a V compound, a W compound, a Mo compound, an Al compound, and a Sn compound And at least one selected from Nb compound, Hf compound, Y compound, Ho compound, Bi compound, La compound, Ce compound and Zn compound, and the ratio of component (A) and component (B) is (B) / (A ) Is a mass ratio of solids of 1/50 to 10/1, and the ratio of component (A) to component (C) is within a range of 1/1000 to 4/10 as a solids mass ratio of (C) / (A). The aqueous surface treatment agent for environmentally-friendly precoat metal materials whose ratio of component (A) and component (D) is the range of 1/50-10/1 as solid content mass ratio of (D) / (A). The method of claim 1, At least the metal oxide sol (B) is selected from zirconium oxide sol, cerium oxide sol, aluminum oxide sol, tin oxide sol, niobium oxide, zinc oxide sol, antimony oxide sol, bismuth oxide sol, yttrium sol and holmium sol 1 type of water-based surface treatment agent. The method of claim 1, The aqueous surface treating agent whose at least 5 mass% of a silane coupling agent (A) is a silane coupling agent which has an amino functional group. The method of claim 1, The water-based surface treating agent which is a mixture of equivalent ratio 50: 1-1:50 of a silane coupling agent (A) which has an epoxy group couple | bonded with the silane coupling agent containing an amino functional group, and an adjacent carbon atom. The metal material which has a dry film of 0.01-1 g / m <2> on the surface as a dry film from the aqueous surface treating agent of any one of Claims 1-4. An environmentally compatible precoated steel sheet in which an upper layer film free of chromium is further formed on the surface of the metal material according to claim 5.