Stock material or miscellaneous articles – Composite – Of metal
Patent
1994-12-09
1996-04-02
Dudash, Diana
Stock material or miscellaneous articles
Composite
Of metal
428463, 428482, 428522, 428523, 4274071, 427409, 427417, 427418, 526213, 526321, 526329, 526338, 5263401, 524437, 524457, B32B 1508, B32B 2516, B32B 2708, B05D 136
Patent
active
055039391
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for the production of a two-coat finish on a substrate surface, in which polymer as binder is applied to the substrate surface, then
The invention also relates to aqueous paints suitable for this process.
The process described above for the production of two-coat finishes is known and is employed in particular in the production of topcoat finishes, especially in the production of metallic finishes on car bodies (cf. eg. DE-A-38 41 540, EP-A-287 144, DE-A-36 28 124, EP-A-195 931 and EP-A-256 549).
The visual impression of the two-coat finishes produced by the process under discussion is very heavily dependent on the spatial distribution and on the spatial orientation of the pigments contained in the basecoat. This is particularly true of metallic finishes. The higher the proportion of metallic pigment particles (especially aluminum pigment particles) present in flake form in the basecoat which are aligned parallel to the substrate surface, the greater the metallic effect. The spatial distribution and orientation of the pigments contained in the basecoat may be disturbed, in particular, after the application of the transparent topcoat and/or during the baking process.
The object on which the present invention is based consists in the provision of a process of the type described above with which two-coat finishes can be obtained whose visual impression, in particular the metallic effect, is improved in relation to the prior art.
This object is surprisingly achieved by employing in stage (1) of the process for the production of the two-coat finish a pigmented basecoat containing, as binder, an emulsion polymer which can be obtained by subjecting a mixture of cycloaliphatic or aliphatic ester of methacrylic acid or acrylic acid which is free from hydroxyl, carboxyl and sulfonic acid groups, or of a mixture of such esters, unsaturated monomer which carries at least one hydroxyl group per molecule, or of a mixture of such monomers, unsaturated monomer which carries at least one carboxyl or at least one sulfonic acid group per molecule, or of a mixture of such monomers, and ethylenically unsaturated monomer which is different from (a), (b) and (c), or of a mixture of such monomers, 100% by weight, to free-radical polymerization in the aqueous phase in the presence of a reaction product (A) and of one or more emulsifiers, the reaction product (A) being obtainable by reacting a mixture of at least one fatty acid of a drying oil and at least one drying oil, and adding a basic aqueous solution, converting the reaction product to an aqueous dispersion.
The emulsion polymer contained in the basecoat employed in accordance with the invention can be prepared by an emulsion polymerization which is known per se. In this case the monomer mixture comprising (a), (b), (c) and (d) is polymerized in an aqueous medium in the presence of one or more emulsifiers and of one or more free-radical initiators. What is essential to the invention is that this free-radical emulsion polymerization is carried out in the presence of the reaction product (A) described in more detail below.
The emulsion polymerization can be carried out by placing water, emulsifier and part of the initiator in a vessel and slowly adding the monomer mixture and, separately from the monomer mixture but in parallel therewith, the remainder of the initiator at the polymerization temperature (in general from 20.degree. to 100.degree. C., preferably from 40.degree. to 90.degree. C). It is also possible to place part of the water and the emulsifier in a vessel and slowly to add a pre-emulsion, prepared from the remainder of the water, the remainder of the emulsifier and the monomer mixture, and, separately from the pre-emulsion but in parallel therewith, the initiator at the reaction temperature. In this case it is preferred, on the one hand, initially to add part of the pre-emulsion (preferably about 30% by weight of the total amount of pre-emulsion to be employed) together with a corresponding partial amount of the initiator, to pr
REFERENCES:
patent: 3258437 (1966-06-01), Peters et al.
patent: 3442835 (1969-05-01), Curtice et al.
patent: 3935140 (1976-01-01), Go et al.
patent: 4064087 (1977-12-01), Das
patent: 4075135 (1978-02-01), Jozwiak, Jr. et al.
patent: 4719132 (1988-01-01), Porter, Jr.
patent: 4798745 (1989-01-01), Martz et al.
patent: 4812335 (1989-03-01), Kuwajima et al.
patent: 5011733 (1991-04-01), Hiraki et al.
patent: 5169884 (1992-12-01), Lindemann et al.
patent: 5322715 (1994-06-01), Jouck et al.
Gast Achim
Lettmann Bernhard
Peitz Birgit
Piontek Susanne
Rink Heinz P.
BASF Lacke & Farben AG
Dudash Diana
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