Graft polymers containing silicon

Claim 2

A graft polymer having a silicon content of from 0.1 to 20% by weight which consists of (a) a graft basis of a homopolymer or copolymers incorporating vinyl ester and/or vinyl alcohol units; and (b) grafted units having the formula (I) ##STR3## wherein R and R' are the same or different and each is a substituted or unsubstituted aliphatic, cycloaliphatic or aromatic group having from 1 to 20 carbon atoms.

Claim 3

A graft polymer as claimed in claim 1 having a silicon content of from 3 to 15% by weight.

Claim 4

A graft polymer as claimed in claim 1 or claim 2 wherein R and R' are the same, and each is a methyl group.

Claim 5

A graft polymer as claimed in claim 1 wherein the graft basis is an optionally partially or completely saponified copolymer of C 2 -C 4 olefin and the vinyl ester of an aliphatic C 1 -C 18 monocarboxylic acid.

Claim 6

A graft polymer as claimed in claim 4 wherein the graft basis is an ethylene/vinyl acetate copolymer having a vinyl acetate content of from 1 to 75% by weight.

Claim 7

A graft polymer as claimed in claim 5 wherein the ethylene/vinyl acetate copolymer has a vinyl acetate content of from 5 to 50% by weight.

Claim 8

A graft polymer as claimed in claims 5 or 6 wherein the vinyl acetate units are partially or completely saponified.

Claim 9

A process for the preparation of a graft polymer as claimed in claim 1 which comprises: (i) reacting an optionally partially or completely saponified homopolymer or copolymer of a vinyl ester of an aliphatic C 1 -C 18 monocarboxylic acid in solvent-free condition or in an organic solvent at a temperature of from 20° to 200° C. with 0.01 to 5% by weight, based on the polymer, of an inorganic or organic base corresponding to formulae II, III, IV, or mixtures thereof Me(OR").sub.n (II); Me(R").sub.n (III); Me(NR".sub.2).sub.n (IV) wherein Me is an element of the first or second main group of the periodic system, n is 1 or 2 and R" is a hydrogen atom or an aliphatic, cycloaliphatic or aromatic group having from 1 to 20 carbon atoms; and (ii) reacting the product of step (i) with one or more cyclic siloxanes of formula (V), ##STR4## wherein R and R' are as defined in claim 1 and x is an integer of from 3 to 10.

Claim 10

A process as claimed in claim 8 wherein R and R' are the same and each is a methyl group and x has a value of 3 or 4.

Claim 11

Coating compositions, sealing compositions, cable sheaths, flexible tubes and moulded plastics whenever made from a graft polymer as claimed in claim 1.