Coating processes – Applying superposed diverse coating or coating a coated base – Synthetic resin coating
Patent
1996-09-03
1998-06-02
Yoon, Tae
Coating processes
Applying superposed diverse coating or coating a coated base
Synthetic resin coating
427409, 4274125, 524507, 524558, 525374, 526280, 526320, 428457, B05D 714, B05D 136, C08F 830, C08F22016
Patent
active
057596310
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a coating composition comprising obtainable from mixture of such monomers, acrylic acid, or mixtures of such monomers, monomer which is different from (a) and (b), or a mixture of such monomers, different from (a), (b) and (c), or a mixture of such monomers, (b), (c) and (d), or a mixture of such monomers, and is different from (a), (b), (c), (d) and (e), or a mixture of such monomers,
The present invention also relates to processes for producing a multilayer protective and/or decorative coating on a substrate surface and to the use of the coating compositions in the sector of automotive refinishing.
Coating compositions based on hydroxyl group-containing polyacrylate resins and crosslinking agents are known, for example, from JP-A 4-1254. In this document, the hydroxyl group-containing polyacrylate resins which are employed as binder are obtainable from hydroxyl group-containing monomers, alkyl acrylates, alkyl methacrylates, optionally styrene and optionally ethylenically unsaturated polymers. In this context it is essential to the invention that the polyacrylate resin has been prepared using 4-t-butylcyclohexyl acrylate and/or 4-t-butylcyclohexyl methacrylate as monomer component. The hydroxyl group-containing monomer employed is, in particular, hydroxyethyl acrylate and/or hydroxyethyl methacrylate.
These coating compositions known from JP-A 4-1254, especially when used as a transparent topcoat over a basecoat, have the particular disadvantage that, when hydroxyethyl acrylate and/or hydroxyethyl methacrylate are used as OH monomer, the resulting coatings are of inadequate adhesion to the basecoat. The further disadvantage of these coating compositions known from JP-A 4-1254 is the inadequate pot life of the coating compositions.
The object of the present invention was therefore to provide coating compositions which, when used as a transparent topcoat over a pigmented basecoat, lead to coatings having an adhesion to the clearcoat which is improved relative to the coating compositions known from JP-A 4-1254. At the same time, the resulting coatings should be of good chemical resistance and good weathering resistance. In addition, the coating compositions should be suitable for automotive refinishing, i.e. they should be able to be cured fully at low temperatures of in general below 120.degree. C., preferably below 80.degree. C. Furthermore, the coating compositions should also reach full cure rapidly at these low temperatures (rapid dust dryness and freedom from tack, and rapid through-drying) while at the same time should be able to be processed for as long (pot life) as possible. Furthermore, the coating compositions should have a good topcoat appearance and, when used as clearcoat over a basecoat, should cause only minimal dissolution of the underlying basecoat and should exhibit a good light/dark effect when viewed at different angles. Finally, the coating compositions should exhibit very good leveling and should exhibit good application characteristics under the conditions of automotive refinishing.
This object is surprisingly achieved by a coating composition of the type mentioned initially, which is characterized in that component (A) is a hydroxyl group-containing polyacrylate resin which is obtainable by polymerizing from 1000 to 5000, a ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of less than 5.0 and an OH number of from 60 to 180 mg of KOH/g, the sum of the proportions by weight of components (a) to (f) always being 100% by weight and the monomers or monomer mixtures employed as component (b) only being those which, on polymerization of the respective monomer alone, produce a polyacrylate and/or polymethacrylate resin having a glass transition temperature of from -10.degree. C. to +6.degree. C. or from +60.degree. C. to 80.degree. C.
The present invention also relates to a process for producing a multilayer coating on a substrate surface using these coating compositions, and to the use of the coating compositions in
REFERENCES:
patent: 4504635 (1985-03-01), Weber, Jr. et al.
patent: 4758642 (1988-07-01), Yezrielev et al.
patent: 5239028 (1993-08-01), Nakagawa et al.
patent: 5279862 (1994-01-01), Corcoran et al.
patent: 5288828 (1994-02-01), Harris et al.
Kageishi Kazuji et al., Resin Composition for Electrocoating Dec. 7, 1989, 4 pages.
Nakagawa Hiroo et al., Acrylpolyol and Two-Oack Urethane Resin Coating Composition Containing Same, Jun. 14, 1988, 2 pages.
Brunnemann Michael
Rink Heinz-Peter
BASF Lacke+Farben AG
Yoon Tae
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