Coil-coating compsn. for metal substrates - contains polyester with carboxyl and hydroxyl gps., acrylate¨ resin, amino resin and siloxane(s)¨ with reactive end gps.

摘要

A coil-coating process for metal objects (I) involves applying and hardening an aq. coating compsn. (II) contg. (A) 10-60 wt% polyester(s) with acid number 35-60 and OH number 40-200 (mg KOH/g), (B) 0-50 wt% acrylate resin(s), (C) 3-28 wt% amino resin(s) and (D), as structure-producing additive, 0.001-1 wt% siloxane cpd(s), with Mn 300-10,000 pref. 500-2500, contg. gp(s), which are reactive towards the functional gps. in (A) and/or (B) (all amts. w.r.t. coating material without water). Specifically (A) has acid number 40-50 and OH number 60-150, and pref. (A) is Uradil 3563 A8-80, 3971 and/or 3563 G7=-G3-80 (RTM); (D) is a siloxane with at least 1 (pref. at least 2) OH, amino, methylol or ester gps.; pref. (D) has the formula HO-(CJ2)n-(SiMe2O)x-SiMe2-(C H2)n-OH (with n = 1-20 (pref. 2-5) and x = 2-30 (pref. 5-15); esp. pref. with n = 3 and x = about 10 or about 25); amts. are 40-55 wt% (A), 0-40 wt% (B), 10-20 wt% (C) and 0.003-0.5 wt% (D); (II) is applied as a one-coat system, or as the primer and/or topcoat of a 2-coat system. USE/ADVANTAGE - An aq. or water-thinnable coil-coating compsn. is provided, which enables metal objects to be coated with layers 20-45 microns thick with a surface structure like that of spray paint. These coatings have good resistance to MEK etc., good ductility and good adhesion. The claims include coated metal objects obtd. by the above process, the use of such coated prods. for the prodn. of domestic equipment, and the use of siloxanes (D) as structure-producing additives. (Dwg.0/0)