| 摘要 |
<p>Thermosetting aqs. coating compsn. comprises (A) 50-97 (65-65) pts. wt. (based on A+B) of (1) an epoxy polymer contg. either (a) 2 terminal 1,2-epoxy groups per mol. and of molecular wt. 1000-5000 (1000-2500), determined by gel permeation chromatography with a polystyrene standard as reference, or (b) 10-150 randomly distributed 1,2-epoxy groups per mol. and of molecular wt. 25000-75000; the polymer having reacted until complete consumption of the epoxy groups with (2) an aqs. soln. of 1-1.25 equiv., per equiv. epoxy group of the epoxy polymer, of a tert. amine comprising cpds. R1R2R3N (where R1 and R2 are opt. hydroxylated 1-2C alkyl, and R3 is opt. hydroxylated 1-4C alkyl, pyridine, N-methyl pyrrole, N-methyl pyrrolidine and/or N-methylmorpholine); (B) 3-50 (15-35) pts. wt. (based on A+B) of a (partly) alkylated amine-aldehyde resin(s). (A) and (B) comprise pref. 0.1-50 wt.% of the coating compsn., the rest comprising water and one or more org. liquid(s) in the ratio 70:30 - 90:10 and the compsn. having a pH of 7.5-12 and opt. contg. an acid (e.g. H3PO4 or its mono- or diesters with (cyclo)aliphatic and aromatic alcohols, citric acid and/or p-toluene sulphonic acids). Used for coating metals e.g. automobiles and coils but partic. for coating cans for food and beverages. The compsn. can also be used for coating paper. It has excellent wetting properties and forms glossy coatings which are resistant to solvents, salt water, detergents and other chemicals.</p> |
