Compositions: coating or plastic – Coating or plastic compositions – Corrosion inhibiting coating composition
Reexamination Certificate
1999-04-22
2003-07-08
Rickman, Holly (Department: 1773)
Compositions: coating or plastic
Coating or plastic compositions
Corrosion inhibiting coating composition
C106S014440, C148S259000, C428S336000, C428S339000, C428S621000, C428S626000, C428S632000
Reexamination Certificate
active
06589324
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an agent for treating metallic surface, which is to be applied to the surface of a metal material such as a steel plate, plated steel plate, alloy-plated steel plate, alloy plate, silicon steel plate, stainless steel plate, shape steel, pipe, wire material and the like and dried to form a rust-proof film, a metal material which has been subjected to a surface treatment with said agent for treating metallic surface (hereinafter to be also referred to as a surface-treated metal material), and to a metal material obtained by applying a resin to said metal material (hereinafter to be also referred to as a coated metal material).
BACKGROUND OF THE INVENTION
To improve corrosion resistance of a cold draw steel plate, a Zn-plated steel plate, a steel plate plated with Zn alloy (e.g., Zn—Ni, Zn—Ni—Co, Zn—Ni—Cr, Zn—Fe, Zn—Co, Zn—Cr, Zn—Mn and the like), a steel plate plated with a metal (e.g., Ni, Cu, Pb, Sn, Cd, Al, Ti and the like), a steel plate plated with an alloy of these metals, and the like, these plates are typically treated with chromate to form a chromate film.
This chromate treatment is largely divided into an electrolytic chromate treatment and a coating chromate treatment. By the electrolytic chromate treatment at the negative electrode using chromic acid as the main component and various other compounds, a chromate film is formed by an electrolytic treatment of the steel plate. By the coating chromate treatment, a chromate film is formed by applying a liquid containing a trivalent or hexavalent chromium as the main component and an inorganic colloidal compound, inorganic anionic, inorganic cationic compound, and the like.
In addition, a coating chromate treatment, a so-called resin type chromate treatment, wherein an organic resin is used, has recently been developed as one of the coating chromate treatments. For example, there have been developed a treatment method wherein a liquid containing chromic acid, amorphous silica, phosphoric compound, and poly(acrylic acid) is applied and a C/Si ratio of the outermost film layer is specified (Japanese Patent Unexamined Publication No. 163385/1990); a method wherein an acrylic copolymer emulsion comprising methyl methacrylate and the like as polymerizable components is added to a chromate liquid under specific conditions and used for the treatment (Japanese Patent Unexamined Publication No. 179883/1990); a method wherein a liquid containing chromic acid, a reduction product of chromic acid, an acrylic emulsion and silica sol under specific conditions is applied (Japanese Patent Unexamined Publication No.215683/1991); a method wherein a liquid containing chromic acid, a reduction product of chromic acid, an acrylic emulsion and a wet type silica sol is used for the treatment (Japanese Patent Unexamined Publication No. 215681/1991); a method wherein a composition for a metallic surface treatment comprising an aqueous emulsion comprising an unsaturated ethylene carboxylic acid component, a hydroxy-containing monomer component and other unsaturated ethylene compound, a water soluble chromium compound, an aqueous colloid containing inorganic compound, and an inorganic compound that reacts with amphoteric metal and forms sparingly water soluble salt, is used (Japanese Patent Unexamined Publication No.230666/1993); and other method.
Of the chromate films, a chromate film formed by an electrolytic chromate treatment suffers less from the elution of Cr but has insufficient corrosion resistance. In addition, the film shows poor resistance to flaw during processing, which in turn results in markedly degraded corrosion resistance after processing. In addition, a chromate film formed by the coating chromate treatment undesirably allows easy elution of the chromium component in the chromate film when used as obtained by the treatment and is problematic from the aspect of pollution. In addition, the corrosion resistance and adhesion to a paint of the film are not entirely satisfactory. The film often obtains flaws during processing and the corrosion resistance of the film is considerably degraded by processing. Moreover, the resin type chromate treatment is insufficient in that a treatment liquid has short life since it becomes a gel and separates into different phases, and the obtained film has insufficient resistance to the elution of chromium.
In view of the recent tendency toward drastically reinforced regulation on the use of chromium (particularly hexavalent chromium) out of the concern of the environmental and pollution problems, corrosion resistant coating compositions free of chromium have been developed. Such composition is exemplified by a polymer emulsion obtained by polymerizing a polymerizable unsaturated monomer containing a specific amount of unsaturated carboxylic acid (Japanese Patent Unexamined Publication No. 222324/1993); a composition containing an acetoacetyl-containing aqueous synthetic resin dispersion as a main component (Japanese Patent Unexamined Publication No. 148432/1993); a mixture of a substantially water insoluble mono- or polybasic salt of special keto acid with a base selected from cation, amine, guanidine and amidine (Japanese Patent Unexamined Publication No. 70715/1993); a resin copolymer of unsaturated carboxylic acid-glycidyl-containing unsaturated monomer—monomer copolymerizable with alkyl acrylate-alkyl acrylate (Japanese Patent Unexamined Publication No.192166/1991) and the like. The film obtained by applying any of these, which is a special resin or a mixture of a special resin and an inorganic compound, has poor corrosion resistance, wherein an increase in the thickness of the film (for example to 3-5 &mgr;m) cannot ensure sufficient corrosion resistance. What is more, the film does not always show superior adhesion to various metals constituting the surface of an iron steel plate or steel plates plated with various metals. Under a wet environment, the film shows dramatically degraded adhesive property, to the point that the film comes off and falls. There exists no film capable of maintaining superior adhesive property even under wet environment. In addition, the film thus formed is easily destroyed during processing and comes off easily.
The film of the present invention resolves the above-mentioned shortcomings in the prior art technique and provides a chromium-free agent for treating metallic surface, which is to be applied to the surface of a metal material, such as steel plate, plated steel plate, alloy-plated steel plate, alloy plate, silicon steel plate, stainless steel plate, shape steel, pipe, wire material and the like, and dried to form a film superior in corrosion resistance, adhesion to a metal material and adhesion to a paint, a metal material which has been subjected to a surface treatment with said agent for treating metallic surface, and to a metal material obtained by applying a resin to said metal material.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides the following.
(1) A chromium-free agent for treating metallic surface comprising the following
(i) at least one of (A) a mixture of an aluminum salt and an inorganic oxide particle and (B) an aluminum-containing inorganic oxide particle comprising aluminum, oxygen and at least one element other than these two
(ii) a salt of a metal other than aluminum
(iii) a phosphorus compound
(iv) a resin and/or a precursor thereof provided that when (i) is a mixture of an aluminum salt and an inorganic oxide particle, the equivalent ratio of phosphorus/aluminum is not less than 0.1.
(2) The agent for treating metallic surface of (1) above, wherein the inorganic oxide particle is a particle of an oxide of at least one element selected from the group consisting of Si, Fe, Ge, Ti, Zr, Mg, Sn, Sb and Al.
(3) The agent for treating metallic surface of (1) above, wherein the inorganic oxide particle is an SiO
2
particle.
(4) The agent for treating metallic surface of any of (1)-(3) above, wherein the inorganic oxide particle content is 2-80 parts by weight p
Hotta Yasunari
Kamo Hiroaki
Odashima Hisao
Shimizu Toshiyuki
Leydig , Voit & Mayer, Ltd.
Rickman Holly
Toyo Boseki Kabushiki Kaisha
LandOfFree
Agent for treating metallic surface, surface-treated metal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Agent for treating metallic surface, surface-treated metal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Agent for treating metallic surface, surface-treated metal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3011267