Fluorine-containing compounds having polyacetalic structure, and process for preparing them

Abstract

1) New fluorine-containing compounds having polyacetalic structure, of general formula: (I)[Rf.sub.m --CH.sub.2 O(CH.sub.2 O).sub.c --CH.sub.2 ].sub.n where: Rf=a perfluorooxyalkylene chain having Mn from 500 to 5,000; m=4-25; c=1-10; n=2-100. 2) A process for preparing them, which comprises carrying out the polycondensation of diols having formula: (II) HORfOH with formaldehyde, in mass or in the presence of solvents, in an acid medium. The compounds of formula (I) can be oligomeric compounds (polymerization degree x.sub.n from 2 to about 20) or polymeric compounds (x.sub.n from about 20 to about 100). They exhibit a high stability to heat and to chemical agents, and Tg values slightly different from the ones of the diols utilized for preparing them.

Dependencies are inferred from the claim text.