Coating processes – Applying superposed diverse coating or coating a coated base – Synthetic resin coating
Patent
1996-10-03
1998-01-20
Yoon, Tae
Coating processes
Applying superposed diverse coating or coating a coated base
Synthetic resin coating
4274123, 524507, 525123, 428517, B05D 704, B05D 300, C08L 7504
Patent
active
057099090
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to filler pastes for use in basecoats for coating polyolefin substrates, to basecoats containing such filler pastes, and to processes for the direct coating of polyolefin substrates.
Externally mounted components for the automotive industry, and numerous parts for non automotive applications, are increasingly being produced from plastic. In addition to materials which have been in common use for decades, such as polyamide and unsaturated polyester resin molding compounds, use is increasingly being made of polyolefins and polyolefin blends. Coating such polyolefins, for example polypropylene as is preferably employed for the automotive industry, along with its blends (e.g. PP-EPDM), however, is problematic because of the low surface tension of these plastics.
Coatings on plastics must possess, in particular, a good adhesion to the plastic substrate concerned. It is known to subject plastic components made of polyolefins such as, for example, polypropylene to physical and/or chemical pretreatment in order to ensure good adhesion to the plastic substrate. The processes known in this context are the following: flame treatment, plasma pretreatment, corona discharge, chemical oxidation, for example with chromosulfuric acid, and chemical adhesion promotion by the application of chlorinated polyolefins to the plastic substrates. A conventional procedure is flame treatment in the first step, in order to ensure adequate adhesion, followed by application of a primer in order, in particular, to cover surface defects in the plastic substrates. The direct, and thus primer-free, coating of special-effect basecoats or solid-color basecoats on polyolefin substrates gives rise to problems since, on the one hand, adhesion to the substrate is not guaranteed and, on the other hand, it is not possible to effect adequate covering of surface defects such as, for example, flow lines. The simple admixture of chlorinated polyolefins, as adhesion promoters, to special-effect basecoats or solid-color basecoats for coating polyolefin substrates is disadvantageous for a number of reasons. In all conventional basecoats, the chlorinated polyolefins used as adhesion promoters impair the formation of the special effect ("flop"). The chlorinated polyolefins exhibit high degrees of incompatibility with common basecoat-binder systems. In addition, the chlorinated polyolefins used as adhesion promoters are very sensitive to light and, if light stabilization in the coating system is inadequate, they may cause premature weathering.
For coating polypropylene substrates, DE-A-40 14 212 discloses special-effect basecoats which contain physically drying binders, chlorinated polyolefins, cellulose acetobutyrate, special-effect pigments, for example metallic pigments or pigments based on mica flakes, color pigments if desired and organic solvents. The basecoats described can be applied directly to the plastic substrate without adhesion problems. When using the special-effect basecoats known from DE-A-40 14 212 for coating plastic substrates without priming the plastic substrates beforehand, however, the problem which occurs is that existing surface defects such as, for example, flow lines cannot be adequately covered. Moreover, use of the plastic substrates coated with the special-effect basecoats in the automotive sector gives rise to problems with regard to stone chip resistance.
The object of the present invention therefore consists in eliminating the above-depicted disadvantages of the prior art. For coating polyolefin substrates such as, for example, polypropylene, polyethylene, polypropylene copolymers and polypropylene blends such as PP-EPDM, therefore, the intention is to provide basecoats which enable direct coating of the polyolefin substrates, ie. whose use enables elimination of the need to use primers, thus creating a considerable cost saving. The basecoats should have a good adhesion to the polyolefin substrate and they should lead in particular, despite omission of a primer, to good covering of surface defec
REFERENCES:
patent: 3594449 (1971-07-01), Binder
patent: 3676391 (1972-07-01), DeRoss
patent: 4914149 (1990-04-01), Fleming et al.
patent: 5030681 (1991-07-01), Asato et al.
Bohm Doris Maria
Gobel Andreas
Leibfarth Frank
Oslowski Hans Josef
BASF Lacke & Farben AG
Yoon Tae
LandOfFree
Filler paste for use in basecoats for coating polyolfin substrat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Filler paste for use in basecoats for coating polyolfin substrat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Filler paste for use in basecoats for coating polyolfin substrat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-723688