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US 4,226,901 AGranted
Method for metallic finish coating
AssigneeKansai Paint Co., Ltd.
InventorsShinji Sugiura, Tadashi Watanabe, Satoru Ito
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AssigneeKansai Paint Co., Ltd.
InventorsShinji Sugiura, Tadashi Watanabe, Satoru Ito
Estimating the term…
In a method for applying a metallic finish coat to a substrate which comprises applying a base coat composed of a metallic paint containing a thermosetting resin as a film-forming ingredient to a substrate, applying a top coat composed of a clear paint containing a thermosetting resin as a film-forming ingredient to the surface of the base coat, and heating both the base coat and top coat to cure them, the improvement wherein the film-forming ingredient of the clear paint in the top coat comprises (A) an acrylic resin having a number average molecular weight of 5,000 to 15,000 and a glass transition temperature of from 5.degree. to 35.degree. C. obtained by copolymerizing (a) 42 to 90 parts by weight of at least one methacrylate selected from alkyl methacrylates with the alkyl moiety having 4 to 18 carbon atoms and (b) 10 to 58 parts by weight of a monomer having an ethylenically unsaturated bond and a hydroxyl group in the molecule, the total amount of components (a) and (b) being 100 parts by weight, and (B) an aminoaldehyde resin, the weight ratio of the acrylic resin (A) to the aminoaldehyde resin (B) being from 80:20 to 65:35.
In a method for applying a metallic finish coat to a substrate which comprises applying a base coat composed of a metallic paint containing a thermosetting resin as a film-forming ingredient to a substrate, applying a top coat composed of a clear paint containing a thermosetting resin as a film-forming ingredient to the surface of the base coat, and heating both the base coat and top coat to cure them, the improvement wherein the top coat consists essentially of
In a method for applying a metallic finish coat to a substrate which comprises applying a base coat composed of a metallic paint containing a thermosetting resin as a film-forming ingredient to a substrate, applying a top coat composed of a clear paint containing a thermosetting resin as a film-forming ingredient to the surface of the base coat, and heating both the base coat and top coat to cure them, the improvement wherein the top coat consists essentially of
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
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Base coat plus clear coat type: the two layers being cured or baked together, i.e. wet on wet
Metallic effect: achieved by multilayers
Of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical: homopolymers or…
Compositions of condensation polymers of aldehydes or ketones ; Compositions of derivatives of such polymers: condensation polymers of aldehydes…
Term ended 20 Nov 1998 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to a method for metallic finish coating of a substrate by a two-coat one-baking process.
In top coat metallic finishes of automobiles, the "one-coat one-baking process" which involves forming a coat of a thermosetting paint containing a metallic powder and baking the as-formed coat has been frequently superseded in recent years by a "two-coat one-baking process" which comprises applying a base coat of a thermosetting paint containing a metallic powder to a substrate, thereafter applying (wet-on-wet) a top coat of a clear thermosetting paint not containing a colored pigment to the base coat, and then baking the base coat and the top coat simultaneously. The main reason for this is that while by the one-coat one-baking process, the metallic powder is attacked by acids, etc. and stains tend to form, the two-coat one-baking process gives coated films being substantially free from staining and having superior aesthetic properties.
However, since in the two-coat one-baking process the base coat and the top coat are prepared from different resins to increase gloss and prevent unevenness of a metallic finish, a difference in properties such as elasticity and the coefficient of expansion arises between the two coats, resulting frequently in the cracking and peeling of the top coat which are not seen in the one-coat one-baking process. In addition, the resulting coating has unsatisfactory water resistance and mechanical properties. It has been strongly desired therefore to remove these defects.
The following Examples and Comparative Examples illustrate the present invention in more detail. In these examples, all parts and percentages are by weight.
(1) Preparation of acrylic resin solution A
An ordinary apparatus for producing an acrylic resin equipped with a stirrer, thermometer, reflux condenser and dropping tank was charged with 67 parts of Swasol #1000 (an aromatic solvent, a trademark for a product of Maruzen Sekiyu Kagaku Kabushiki Kaisha, Japan), and when the temperature reached 132.degree. C., a monomeric mixture consisting of 60 parts of n-butyl methacrylate, 19 parts of 2-ethylhexyl methacrylate, 18 parts of 2-hydroxyethyl methacrylate, 3 parts of methacrylic acid and 1.9 parts of .alpha.,.alpha.'-azobisisobutyronitrile was added dropwise over the course of 3 hours.