Patent ID: 6087066
Filing Date: 2000-07-11
Classification: C08F,G03F,Y10S

Abstract:
A polyvinyl acetal containing the units A, B, C and D, wherein A is present in an amount of 0.5 to 20 wt.-% and is of the formula ##STR10## B is present in an amount of 15 to 35 wt.-% and is of the formula ##STR11## C is present in an amount of 10 to 50 wt.-% and is of the formula ##STR12## wherein R.sup.1 is an alkyl group with up to 4 carbons, which is optionally substituted by an acid group, or a phenyl group, to which an acid group is attached, wherein the phenyl group optionally comprises 1 to 2 further substituents selected from halos, amino, methoxy, ethoxy, methyl and ethyl groups, or is a group X--NR.sup.6 --CO--Y--COOH, wherein X is an aliphatic, aromatic or araliphatic spacer group, R.sup.6 is hydrogen or an aliphatic, aromatic or araliphatic moiety and Y is a saturated or unsaturated chain- or ring-shaped spacer group, and this unit C may be contained several times with various moieties R.sup.1 independent of one another, and D is present in an amount of 25 to 70 wt.-% and is of the formula ##STR13## wherein n is an integer from 1 to 3 andR.sup.2 and R.sup.3 are a hydrogen or a methyl group, andR.sup.4 and R.sup.5 independent of one another are alkyl groups having no more than 4 carbons or R.sup.4 and R.sup.5, together with the two carbons they are attached to, represent a 5- or 6-membered carbocyclic ring.