| 摘要 |
Aq. dispersions with a content of organic solids of 30-80 wt.%, are based on (I) 60-90 wt.% (w.r.t. I+II) of oil-free polyester or alkyd resin, (II) 10-40 wt.% (w.r.t. I+II) of a crosslinking agent, (III) 0-1.5 wt.% (on I+II) of an emulsifier and (IV) conventional adjuvants and assistants. Component (I) has an ave. functionality of 2.5-10, an ave. degree of condensation of 10-25, an ave. urethane gp. content of 3-6 per mol., and contains residues of 2,2-di(hydroxymethyl) carboxylic acid corresponding to an acid value of 15-30, at least 80% of which are neutralised. The crosslinker (II) comprises a mixt. of (a) a water-soluble aminoplast resin and (b) blocked polyisocyanate with a wt. ratio a/b = 0.33-1.0. The dispersion has an organic solvent content of less than 8 wt.%.
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