Anionisch stabilisierte, wäßrige Polyvinylbutyraldispersionen, Verfahren zu ihrer Herstellung und ihre Anwendung

摘要

The prodn. of water-dilutable polyvinyl butyral (PVB) dispersions (I) comprises reacting (A) aliphatic acid(s) contg. 1-3 isocyanate-reactive gps. and 1-3 acid gps. with (B) polyisocyanates with an average functionality of at least 2, in an amt. such that the ratio of NCO gps. in (B) to NCO-reactive gps. in (A) = (2.2:1)-(1.7:1), until the content of residual NCO gps. reaches the calcd. value, then reacting 25-75% of the remaining NCO gps. with (C) mono-alcohol(s) and/or mono-amine(s), until the calculated NCO gp. content is obtd., and reacting the NCO- functional emulsifier resin thus obtd. with (D) a mixt. of (D1) 30-100 wt% PVB and (D2) 0-70 wt% suitable plasticiser resin(s) in the presence of suitable solvents, until all the NCO gps. are completely reacted, to give a prod. contg. acid gps. in an amt. such that the solid resin has an acid no. of 5-50 mg/g. Also claimed are: (i) aq. PVB dispersions (I) obtd. by this process, and aq. PVB dispersions contg. 0.5-20 wt% organic solvent; (ii) mixts. of aq. binders contg. (I), pref. together with aq. dispersions of phenolic resins or amino resins.