Low solvent stoving enamels - based on acrylic copolymer, epoxide and mixts. of organic solvents

摘要

Low solvent stoving enamels comprise (A) an acrylate resin; (B) an epoxide resin; (C) a mixt. of organic solvents, and opt. pigments, catalysts and other additives. (A) is a copolymer, contg. in polymeric linking, 10-35% carboxylic acids contg. alpha:beta-ethylenic links and having a Fikentscher K value of 15 and an acid value of 70-250 mg. KOH/g. (B) contains >=2 oxirane gps/mol., (C) comprises 20-80% of a solvent boiling at 100-280 degrees C and dielectric constant of 2-4.99, and 80-20% of a solvent boiling at 80-200 degrees C and dielectric constant 5-27. The wt. ratio of (A)/(B) is 5 to 27 and the wt. ratio of (A+B)/(C) is 7/3 to 5/5. Used for painting household appliances and as undercoating layers for cars. They may be applied from prepns. contg. very little solvent. In an example, prepns. contg. >70% esp. 75-85% dry wt., may be sprayed onto vertical surfaces where they flow out well and on stoving form coatings having good mechanical props, resistance to chemical agents and solvents and showing good protection against corrosion. They may also be applied onto vertical surfaces to form layers 40 um thick, without running and without the presence of thixotropic agents.