| 摘要 |
<p>A stable polymer dispersion in a hydrocarbon is prepd. by polymerising olefinically unsatd. monomers contg. a H2C-C=gp., and giving (co)polymer insoln. in the hydrocarbon reaction medium, in a liquid medium contg. aliphatic hydrocarbon(s) and 49 wt.% of non-aliphatics, using free-radical initiators and in presence of oil-sol. synthetic resins contg. ester gps. In the prepn., (a) a soln. of 10-40 (21-40) wt.% of an alkyd resin in the liquid medium is heated to 50-70 degrees C, (b) 90-60 wt.% of a mixt. contg. (1) 10-50 wt.% styrene, alpha-methylstyrene, and/or vinyltoluene, (2), 10-35 wt.% hydroxyalkyl (meth)acrylates where the alkyl gp. has 2-8C, (3) 15-50% alkyl acrylates where the alkyl gp. has 6-14C, or other ethylenically unsatd. monomers, and (4) 1-5% alpha,beta-unsatd. aliphatic mono- or dicarboxylic acids or anhydrides, is added gradually to the soln., in presence of the initiators and with maintenance of the temp., and (c) when 70-90% of the mixt. (b) has been polymerised, the temp. is raised gradually to 80 plus-or-minus 2 degrees C and polymerisation is continued until the reaction mixt. is free from monomers. The dispersions can be combined with aminoplasts to give coating compsns. Normal appts. and operating conditions are used. The dispersions are free from coagulate. The compsns. after baking at 120-150 degrees C for 20-30 minutes, give coatings with high resistance to weathering in industrial atmos.</p> |
