Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
1999-12-10
2001-02-27
Cameron, Erma (Department: 1762)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C252S389300
Reexamination Certificate
active
06194033
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rust-preventive composition for the surfaces of metals such as steel sheets used in automobiles, construction material products and so forth.
2. Description of the Prior Art
Steel sheets used in automobiles and construction material products, in particular, zinc-plated (galvanized) or zinc-alloy-plated steel sheets are coated before their use. They are passed through various steps before coating, and also are left uncoated for a fairly long time in that course. Hence, there are problems that the plated steel sheets may rust in that course, or various substances may become adsorbed on or adhere to their surfaces, so that coating materials to be applied thereafter may have a poor adhesion.
Accordingly, the plated steel sheets are subjected to chromating as primary rust-preventive treatment made before coating. Corrosion resistance attributable to this chromating may commonly only last for about 48 hours in a salt spray test made according to JIS Z-2371, and is insufficient if the chromating only is made, when left in a severe corrosive environment over a long period of time. Under such circumstances, a coating type special method of chromating is proposed in which a chromating liquid to which a silica sol has been added is used, at the stage of chromating. This method can provide a corrosion-resistant effect lasting for 100 to 200 hours in the salt spray test.
However, hexavalent chromium is contained in coating films themselves which are formed by such special chromating. This hexavalent chromium is known to cause an allergy (chromate ulcer) when the skin is stained with it. A possibility of carcinogenesis is also pointed out. Thus, there is a problem on safety. As a method not making use of any hexavalent chromium, it has been proposed to apply trivalent chromium plating further on zinc alloy plating. This method, however, can not achieve a sufficient corrosion resistance.
SUMMARY OF THE INVENTION
Accordingly, it is sought to provide a technique for making rust-preventive treatment on metal surfaces, which can achieve a sufficient corrosion resistance in the salt spray test even without making any chromating, and also promises a high safety.
The present invention meets such a demand. Thus, an object of the present invention is to provide a metal surface rust-preventive composition which can achieve a sufficient corrosion resistance without making any chromating and also has a high safety.
To achieve the above object, the present invention provides a rust-preventive composition comprising;
(A) an aromatic compound i) containing in one molecule at least one group selected from the group consisting of an —N═N— group, a >C═N— group, a >C═O group and an —N═O group and ii) having an absorption band in a visible region of from 530 nm to 750 nm;
(B) a colloidal silica;
(C) a film-forming polymeric compound containing in one molecule a group selected from the group consisting of an —OH group and a —COOH group; and
(D) an organic solvent.
DESCRIPTION OF THE REFERRED EMBODIMENTS
The present invention will be described below in detail.
(A) Aromatic Compound:
The component-(A) aromatic compound may be any aromatic compound as long as it fulfills the conditions of i) containing in one molecule at least one group selected from the group consisting of an —N═N— group, a >C═N— group, a >C═O group and an —N═O group and ii) having an absorption band in a visible region of from 530 nm to 750 nm.
As the aromatic compound that fulfills the above conditions, preferably usable are dyes such as direct dyes, acid dyes, basic dyes, mordant dyes, acid mordant dyes, vat dyes, disperse dyes, oil colors, reactive dyes and food colorants.
As specific examples of the above dyes, they may include the following.
Examples of Direct Dyes:
C.I. Direct Violet 1, 7, 9, 12, 22, 35, 47, 48, 51, 90, 94, 98;
C.I. Direct Blue 1, 2, 6, 8, 15, 22, 25, 41, 71, 76, 77, 78, 80, 86, 96, 98, 106, 108, 120, 158, 160, 163, 165, 168, 192, 193, 194, 195, 196, 199, 200, 201, 202, 203, 207, 225, 226, 236, 237, 246, 248, 249;
C.I. Direct Green 1, 6, 8, 28, 30, 31, 33, 59, 63, 64, 74;
C.I. Direct Brown 2, 44; and
C.I. Direct Black 17, 19, 22, 32, 38, 51, 56, 62, 71, 74, 75, 77, 94, 105, 106, 107, 108, 112, 113, 117, 118, 132, 133, 146.
Examples of Acid Dyes:
C.I. Acid Violet 7, 11, 15, 31, 34, 35, 41, 43, 47, 48, 49, 51, 54, 66, 68, 75, 78, 97, 106;
C.I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 54, 59, 60, 62, 72, 74, 78, 80, 82, 83, 90, 92, 93, 100, 102, 103, 104, 112, 113, 117, 120, 126, 127, 129, 130, 131, 138, 140, 142, 143, 151, 154, 158, 161, 166, 167, 168, 170, 171, 175, 182, 183, 184, 187, 192, 199, 203, 204, 205, 229, 234, 236;
C.I. Acid Green 3, 7, 9, 12, 16, 19, 20, 25, 27, 28, 35, 36, 40, 41, 43, 44, 48, 56, 57, 60, 61, 65, 73, 75, 76, 78, 79;
C.I. Acid Brown 295; and
C.I. Acid Black 1, 2, 7, 24, 26, 29, 31, 44, 48, 50, 51, 52, 58, 60, 62, 63, 64, 67, 72, 76, 77, 94, 107, 108, 109, 110, 112, 115, 118, 119, 121, 122, 131, 132, 139, 140, 155, 156, 157, 158, 159, 191.
Examples of Basic Dyes:
C.I. Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28;
C.I. Basic Blue 1, 3, 5, 7, 9, 19, 21, 22, 24, 25, 26, 28, 29, 40, 41, 44, 45, 47, 54, 58, 59, 60, 64, 65, 66, 67, 68;
C.I. Basic Green 1, 4, 6; and
C.I. Basic Black 2, 8.
Examples of Mordant Dyes and Acid Mordant Dyes:
C.I. Mordant Violet 1, 5, 44;
C.I. Mordant Blue 1, 7, 8, 13, 29, 44, 47, 48, 58, 75, 76;
C.I. Mordant Green 11, 15, 17, 47; and
C.I. Mordant Black 1, 3, 7, 9, 11, 17, 26, 32, 38, 43, 44, 51, 54, 65, 75, 77, 84, 85, 86, 87.
Examples of Vat Dyes:
C.I. Vat Violet 1, 2, 9, 13, 21;
C.I. Vat Blue 1, 3, 4, 5, 8, 12, 14, 18, 19, 20, 29, 35, 41, 64, 66, 67, 72;
C.I. Vat Green 1, 2, 8, 9, 13, 43, 44, 45;
C.I. Vat Brown 3, 72; and
C.I. Vat Black 8, 9, 13, 14, 20, 25, 27, 29, 36, 56, 57, 59, 60.
Examples of Disperse Dyes:
C.I. Disperse Violet 1, 4, 8, 10, 18, 23, 24, 26, 28, 30, 33, 37;
C. I. Disperse Blue 1, 3, 5, 6, 7, 20, 26, 27, 43, 44, 52, 54, 55, 56, 58, 60, 61, 62, 64, 72, 73, 75, 79, 81, 85, 87, 90, 91, 92, 94, 97, 98, 99, 103, 104, 105, 106, 108, 113; and
C.I. Disperse Black 1, 2, 10, 26, 27, 28, 29, 30, 31.
Examples of Oil Colors:
C.I. Solvent Violet 8, 13, 14, 21, 27;
C.I. Solvent Blue 2, 11, 12, 25, 35, 36, 55, 73; and
C.I. Solvent Black 3, 5, 7, 22, 23, 123.
Examples of Reactive Dyes:
C.I. Reactive Violet 1, 2, 4, 5, 8, 9, 10;
C.I. Reactive Blue 1, 2, 3, 4, 5, 7, 8, 9, 13, 14, 15, 17, 18, 19, 20, 21, 25, 26, 27, 28, 29, 31, 32, 33, 34, 37, 38, 39, 40, 41, 43, 44, 46;
C.I. Reactive Green 5, 6, 7, 8;
C.I. Reactive Brown 10; and
C.I. Reactive Black 1, 3, 4, 5, 6, 8, 9, 10, 12, 13, 14, 18.
Examples of Food Colorants:
C.I. Food Violet 2;
C.I. Food Blue 1, 2; and
C.I. Food Green 2.
Of these, preferred dyes are dyes insoluble in water. Among those exemplified above, oil colors are preferred.
The component-(A) aromatic compound may be used alone or in combination of two or more types.
(B) Colloidal Silica:
The component-(B) colloidal silica is a colloid comprising i) a dispersion medium comprised of water, an organic solvent such as methanol, propanol, isopropanol or ethylene glycol, or a mixed solvent of water and the organic solvent and ii) ultrafine silica particles (usually having a particle diameter of from 5 to 500 nm) dispersed therein.
As a typical process for producing colloidal silica by using the water, a method is known in which hydrochloric acid is added to an aqueous sodium silicate solution. As a typical process for producing colloidal silica by using the organic solvent, a method is known in which a silicate such as tetraethoxysilane is subjected to hydrolysis reaction in an organic solvent such as isopropanol and in the presence of a small quantity of a mixed catalyst of pure water and ethyl amine or the like. The colloidal silica used in the present invention, however, is not particularly limited to those produced by these processes. Those obtained by any known processes may be used.
The component-(B) coll
Shimizu Toshihide
Watanabe Mikio
Cameron Erma
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Shin-Etsu Chemical Co. , Ltd.
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