Patent ID: 8529922

Claim:
A polymer which (A) comprises a plurality of polymeric molecules each of which consists essentially of (i) a polymer backbone which comprises a plurality of repeating units having the formula —CF 1 F 2 —CO—O— (1) wherein F 1 is hydrogen and F 2 is hydrogen or methyl, the repeating units being the same or different, and (ii) at least one terminal unit which has the formula - b -Cy (2) wherein Cy consists of an n-alkyl moiety containing 18-24 carbon atoms, or an n-alkyl moiety containing 18-24 carbon atoms and a polyoxyalkylene moiety, and b is a bond or a moiety which has a valence of at least 2 and which links the Cy moiety to the polymer backbone; wherein each terminal unit having formula (2) is a moiety selected from the group consisting of (2A) moieties (i) in which b is a bond, (ii) which have the formula -Cy and (iii) which are directly linked to the terminal —CO—O— moiety of one of the repeating units having formula (1), (2B) moieties (i) in which b is a moiety having the formula —O—CO—, (ii) which have the formula —O—CO-Cy and (iii) which are directly linked to the terminal —CF 1 F 2 — moiety of one of the repeating units having formula (1), and (2C) moieties (i) in which b is a moiety having the formula —R pbalc —CO —, (ii) which have the formula —R pbalc —CO-Cy where R pbalc is the residue of a polyol, and (iii) which are directly linked to the terminal —CO—O— moiety of one of the repeating units having formula (1); wherein at least some of the polymeric molecules contain at least three Cy moieties (B) has a crystalline melting temperature, Tp, of at least 40° C., an onset of melting temperature, To, such that the value of (Tp−To) is less than Tp 0.7 , and a heat of fusion of at least 10 J/g; and (C) has a number average molecular weight, Mn, of less than 10,000.