Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2001-12-10
2003-08-12
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S447000, C428S413000, C428S414000, C528S025000, C528S044000, C528S370000, C528S371000
Reexamination Certificate
active
06605356
ABSTRACT:
TECHNICAL FIELD
This invention relates to a metal surface treatment agent that is used to prevent the corrosion of a metal and improve the adhesion between a metal and a paint, and to a substrate that has been surface treated with this agent, and can be applied in a variety of industrial fields that make use of metal products, such as construction materials, electrical equipment, machinery, and automobiles.
BACKGROUND ART
Corrosion prevention treatments with numerous inorganic materials, metals, and organic materials have been performed in the past in an effort to protect metal surfaces from various corrosive environments. Many different corrosion preventive agents have been used up to now, including water-soluble corrosion preventive agents, vaporizable corrosion preventive agents, and oil-based corrosion preventive agents. Water-soluble corrosion preventive agents are generally intended for temporary, short-term use, and are not used for extended periods. Vaporizable corrosion preventive agents exhibit their inherent corrosion preventive effects in a closed environment. Oil-based corrosion preventive agents offer relatively strong corrosion preventive effects and can stand up to prolonged use, and come as liquid corrosion preventive oil, sticky corrosion preventive grease, and solutions produced by dissolving corrosion preventive additives or film-forming agents in an organic solvent. However, the liquid corrosion preventive oil and corrosion preventive grease cannot be used as primers for paints and so forth because they leave the surface tacky after treatment. Also, the film thickness has to be increased for adequate corrosion preventive performance to be realized. Japanese patent 2,682,168 discusses an alternative to such materials, which is a combination of an organosilicon compound and an epoxy resin having hydroxyl groups. While this material does indeed provide an excellent corrosion preventive effect through a curing reaction, the film needs to be at least 10 microns thick for the corrosion preventive effect to be realized.
Aluminum and aluminum alloys find use in many different applications because of their light weight. However, since they have an aluminum oxide film on the surface thereof, paint does not adhere well when applied directly thereto. Many chemical conversion treatments have been proposed for a paint primary coating or undercoating, and numerous patent applications have been filed before, but the chromate process is the most prevalent today. A chromate treatment, however, is undesirable from the standpoint of the environment, making non-chromate treatments more attractive. A method involving treatment with an alkali metal aqueous solution has also been proposed in an effort to impart corrosion resistance, antistatic properties, and so forth to a metal surface, but obtaining the desired characteristics requires immersion in boiling water or an acid as an after-treatment.
The present invention provides a metal surface treatment agent that satisfies these requirements, that is, one that securely adheres to metal articles such as aluminum and aluminum alloys, exhibits an excellent corrosion preventive effect even with a thin film thickness, and has an excellent plasticity and adhesion to paints, and provides a metal material that has been surface treated with this agent.
DISCLOSURE OF THE INVENTION
As a result of diligent investigation, the inventors arrived at the present invention upon discovering that a composition comprising an organosilicon compound having three carbonyl groups and an alkoxysilyl group, an epoxy resin modified with an alkanolamine, a blocked polyisocyanate, and an amino resin exhibits excellent corrosion prevention properties and paint adhesion when used on metals.
Specifically, the present invention relates to:
(1) a metal surface treatment agent, comprising the following components (A) to (D):
(A) at least one organosilicon compound having three carbonyl groups and at least one alkoxysilyl group, in a weight ratio of 5 to 15 when the total of the components (A) to (D) is 100;
(B) at least one epoxy resin modified with an alkanolamine, in a weight ratio of 10 to 30 relative to the above total;
(C) at least one blocked polyisocyanate, in a weight ratio of 50 to 70 relative to the above total; and
(D) at least one amino resin in a weight ratio of 5 to 15 relative to the above total,
(2) the metal surface treatment agent according to (1) above, wherein the (A) organosilicon compound having three carbonyl groups and at least one alkoxysilyl group is represented by the following general formula (1):
[where said compound includes an enol form compound that is a tautomer; in general formula (1), R
1
and R
3
are C
1
to C
5
alkyl groups, R
2
and R
4
are C
2
to C
10
alkylene groups, and x, y, and z are each 0 or 1],
(3) the metal surface treatment agent according to (1) above, wherein the epoxy resin in the (B) epoxy resin modified with an alkanolamine is a bisphenol-based epoxy resin.
(4) the metal surface treatment agent according to (1) above, wherein the (C) blocked polyisocyanate is represented by the following general formulas (2) and/or (3):
[where R
7
and R
8
in general formulas (2) and (3) are C
1
to C
5
alkyl groups],
(5) the metal surface treatment agent according to (1) above, wherein the (D) amino resin is a melamine resin, and
(6) a metal material having a film formed by coating with the metal surface treatment agent according to any of (1) to (5) above, the film having a corrosion resistance, paint film adhesion, excellent plasticity and high surface hardness.
BEST MODE FOR CARRYING OUT THE INVENTION
The organosilicon compound having three carbonyl groups and at least one alkoxysilyl group used in the present invention (hereinafter abbreviated as a tricarbonyl compound) has been disclosed along with a method for synthesizing this compound in Japanese Patent Application Laid-Open Nos. H9-3076 and 3077, and this disclosed compound can be used favorably.
The alkanolamine in the epoxy resin modified with an alkanolamine used in the present invention (hereinafter abbreviated as a modified epoxy resin) can be an alkanolamine having primary or secondary amino groups capable of undergoing an addition reaction with the epoxy groups of the epoxy resin, and diethanolamine can be used to particular advantage.
Examples of the epoxy resin in the epoxy resin modified with an alkanolamine used in the present invention include bisphenol A and F epoxy resins based on bisphenol A. Other examples include brominated epoxy resins obtained by substituting some of the hydrogens in the benzene rings of a bisphenol A-based epoxy resin with bromine, dimeric acid-based glycidyl ester epoxy resins, phenoxy resins, glycidylamine epoxy resins, novolac epoxy resins, glycidyl ester epoxy resins, biphenyl epoxy resins, and cycloaliphatic epoxy resins.
Examples of the blocked polyisocyanate used in the present invention (hereinafter abbreviated as a blocked isocyanate) include those obtained by reacting tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4-(2,6) diisocyanate, 1,3-(isocyanate methyl) cyclohexane, isophorone diisocyanate, trimethylhexane diisocyanate, or dimeric acid diisocyanate with a blocking agent such as phenol-, lactam-, active methylene-, acid amide-, imide-, amine, imidazole-, urea-, imine, or oxime-based blocking agent in accordance with a customarily used method. Phenol-, lactam-, acid amide-, active methylene-, and oxime-based blocking agents are preferred, and an oxime-based blocking agent is Particularly favorable. Examples of oxime-based blocking agents include formaldoxime, acetaldoxime, methyl ethyl ketoxime, and cyclohexanone oxime.
Examples of the amino resin used in the present invention include butylated urea resins, butylated melamine resins, methylated melamine resins, and butylated benzoguanamine resins, but a methyl
Kumagai Masashi
Ouchi Takashi
Tsuchida Katsuyuki
Dawson Robert
Flynn ,Thiel, Boutell & Tanis, P.C.
Keehan Christopher M
Nikko Materials Co., Ltd.
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