| 摘要 |
<p>A coating powder (I) contg.: (A) an OH gp.-contg. binder with an OH number of 25-200 and an average mol. wt. (calculated from the OH content) of 400-10,000, which is solid at below 40 degrees C and liq. at above 130 degrees C; (B) a poly-addn. cpd. contg. uretedione gps. and opt. free NCO gps., based on aliphatic and/or cycloaliphatic di- isocyanates, which is solid at below 40 degrees C and liq. at above 125 degrees C; (C) a component with COOH and/or anhydride gps. which is solid at below 40 degrees C and liq. at above 160 degrees C, comprising: (C1) 4-20C (cyclo)aliphatic dicarboxylic acids; (C2) mono- and/or polymeric opt. modified anhydrides of such acids; and/or (C3) 4-18C hydroxycarboxylic acids; (D) a component with a mol. wt. of 200-5000 contg. gps. which are reactive towards COOH and/or anhydride gps.; and opt. (E) known coating powder additives, etc.. The amts. of components (A-D) are such as to provide 0.6-1.4 NCO gps. from (B) (including those in dimeric form as uretedione) to each OH gp. from (A) and 0.3-1.5 reactive gps. from (D) to each carboxyl equiv. from (C) (with one COOH gp. = 1 equiv. and one anhydride gp. = 2 equivs.), and the amt. of (C) and (D) is 10-40 wt.% of the total amt. of components (A)-(D).</p> |
