| 摘要 |
<p>An aq. binder comprises a combination of: (A) 65-97 wt.% aq. polyol of 23 degrees C viscosity of 25-15,000 mPa.s; and (B) 3-35 wt.% polyisocyanate component of 23 degrees C viscosity of 50-10,000 mPa.s contg. at least one organic polyisocyanate. The equiv. ratio of NCO gps. in (A):OH gps. in (B) = 0.3-2:1. The novel feature is that component: (A) comprises a mixt. of: (A1) an OH contg. aq. polyester dispersion or soln. comprising an OH-, carboxylate- and/or sulphonate-gp.-contg. polyester resin of ave. mol.wt. (Mw) 1,000-40,000, OH No. 15-100 mg KOH/g dispersion or soln. and acid no. (COOH or COOH + SO3H) 2-30 mg KOH/g, this polyester being the reaction prod. of components (a1)-(a4) as listed below; and (A2) a physically-drying aq. dispersion of a polyurethane contg. carboxylate and/or sulphonate gps. Reaction components (a1)-(a4) are as follows: (a1) 65-100 wt.% polyester pre-condensate from (i) 0-40 wt.% monocarboxylic acids, (ii) 20-65 wt.% di-, tri- and/or tetra-functional alcohols, (iii) 20-60 wt.% di- and/or tri-functional carboxylic acids or anhydrides and (iv) 0-10 wt.% sulphonate-, carboxyl- and/or OH-contg. component; (a2) 0-15 wt.% carboxylic acid anhydride or hydroxycarboxylic acid; (a3) 0-22 wt.% of an at least difunctional isocyanate component; and (a4) 0-8 wt.% mono-, di- and/or tri-functional substance with OH and/or amino gps. Also claimed is the prodn. which involves introducing the various auxiliaries or additives for (A) prior to polyisocyanate (B), such introduction being by simple stirring such that rather special appts. nor a further viscosity adjustment is required.</p> |
