Coatings based on fluoropolyethers

Fluoropolymers based on fluoropolyethers for the preparation of crosslinkable high dry formulations, pure or in admixture with each other, having the formula:

• T"--(R.sub.h2).sub.y (R.sub.H).sub.x --R.sub.F --(R.sub.H).sub.x --(R.sub.h1).sub.y' T'.sub.a
• wherein ##STR47## wherein R.sub.f is a fluoropolyether chain of number average molecular weight between 500 to 5000;
• wherein Y and Y' are equal to or different from each other and being F or CF.sub.3 ;
• x is an integer from 0 to 10;
• R.sub.H is selected from the group consisting of a linking bivalent radical of a linear aliphatic --(CH.sub.2).sub.m --, wherein m is an integer from 1 to 20, (OCH.sub.2 CH.sub.2).sub.m ' wherein m' is an integer from 1 to 6, (alkylene)-cycloaliphatic, (alkylene)aromatic, and mixtures thereof, wherein the (alkylene)-cycloaliphatic, and (alkylene) aromatic optionally have heteroatoms in the ring or in the chain, the number of carbon atoms of the cycloaliphatic moieties being from 3 to 20, for the aromatic moieties from 5 to 30;
• R.sub.F and R.sub.H do not contain groups capable of linking by means of hydrogen bonds to basic acceptors;
• R.sub.h1 and R.sub.h2, are equal to or different from each other, are linking bivalent radicals, contain at least a functional group capable of linking by means of hydrogen bonds with basic acceptors and are selected from the group consisting of ##STR48## y and y' are equal to or different from each other, are integers from 0 to 1, at least one of y and y' being different from 0;
• T'.sub.a equals --(CH.sub.2 CH.sub.2 O).sub.n --(R.sub.H).sub.x --T.sub.a wherein n is an integer from 0 to 6;
• T" equals (CH.sub.2 CH.sub.2 O).sub.n --(R.sub.H).sub.x' --T.sub.b ;
• x' is an integer from 0 to 10, x' is the same or different than x;
• and T.sub.a and T.sub.b being hydrogen or a reactive terminal capable of rendering the fluoropolymers at least bi-functional and reactive towards ionic and radical crosslinking agents and T.sub.a being equal to or different from T.sub.b such that T.sub.a and T.sub.b end groups are not contemporaneously H.