Coating processes – With post-treatment of coating or coating material – Heating or drying
Patent
1996-01-11
1998-06-02
Niland, Patrick D.
Coating processes
With post-treatment of coating or coating material
Heating or drying
4273722, 4273855, 525123, 525131, 525455, B05D 302, C08F 830, C08F 800, C08L 7500
Patent
active
057596301
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP94/01590 filed May 17, 1994.
The present invention relates to a process for the production of textured coatings on plastics surfaces, using coating compositions based on hydroxyl group-containing binders and polyisocyanates as crosslinking agents and using pulverulent texturing agents.
Plastics surfaces, for example car bumpers, are often coated with texturing, matting coatings, in order to obtain textured plastics surfaces. It is known to employ coating compositions containing organic solvents and based on hydroxyl group-containing binders and polyisocyanates, which contain additives in paste form, containing pulverulent texturing agents, and matting agents in order to obtain textured surfaces of plastics components on cars, especially for refinishing. The texturing agent employed in this context is, for example, ground polypropylene. The matting agent used is, for example, silicic acid. With the aid of the matting agent, the coating composition intended for the textured surface is adjusted to the degree of gloss of the plastics surface. To ensure good adhesion to the plastics substrate, elasticized binders are employed.
However, the problem which occurs with the previously known texturing coating compositions for plastics components on cars is that dried-on particles can fall back into the paint from the can edge of the respective containers and, as so-called bittiness, can interfere with processing and lead to paint defects. It is not possible to sieve off these dried-on product particles before processing, i.e. before the application of the coating compositions, since otherwise the pulverulent texturing agent would also be removed.
The object of the present invention was therefore to avoid the above-described disadvantages of the previously known texturing coating compositions. The intention was to provide a process for the production of textured coatings on plastics surfaces, especially for refinishing, using coating compositions based on hydroxyl group-containing binders and polyisocyanates, this process being intended to enable the sieve removal, shortly before application, of any dried product particles formed. The coating compositions used in the process were to contain pulverulent texturing agents and the matting agents required to adjust the desired degree of gloss. In addition, the process was to enable trouble-free incorporation of the pulverulent texturing agents into the plastics-coating compositions.
The object of the present invention is surprisingly achieved by a process for the production of textured coatings on plastics surfaces, using coating compositions based on hydroxyl group-containing binders and polyisocyanates as crosslinking agents, and using pulverulent texturing agents. The process according to the invention is characterized in that, initially, a solution of the hydroxyl group-containing binder (I) is mixed with an elastic matting paste (A) comprising saturated hydroxyl group-containing polyester having a hydroxyl number of from 100 to 160 mg of KOH/g and a number-average molecular weight of from 800 to 2500, hydroxyl group-containing Cardura-modified acrylate copolymer having a hydroxyl number of from 30 to 250 mg of KOH/g and an acid number of from 0 to 50 mg of KOH/g, organic solvent, matting agents and additives, the total weight of the elastic matting paste (A) being in each case 100% by weight, mixed with the solution of the hydroxyl group-containing binder (I), the mixture is subsequently mixed together with polyisocyanates (II) as crosslinking agents, other organic solvents if desired and with the pulverulent texturing agent, the resulting coating composition is applied to the plastics substrate, and the coating is dried.
Suitable hydroxyl group-containing binders (I) include both resins produced by addition polymerization and those produced by condensation polymerization. Particularly preferred resins are hydroxyl group-containing polyacrylate resins having OH numbers of from 30 to 250 mg of KOH/g and acid numbers of from 0 to 50 mg
REFERENCES:
patent: 4108840 (1978-08-01), Friedlander
patent: 4555535 (1985-11-01), Bednarek et al.
patent: 4578426 (1986-03-01), Lenz et al.
patent: 5322897 (1994-06-01), Jung et al.
Rubbert Bernhard
Vosskuhl Annegret
BASF Lacke & Farben AG
Niland Patrick D.
LandOfFree
Process for the production of textured coatings on plastics surf does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the production of textured coatings on plastics surf, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the production of textured coatings on plastics surf will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1457196