. . . "ivalent oxaalkanediyl radicals derived from diethylene glycol or triethylene glycol, R4 is alkanediyl having 2 to 6 cycloalkanediyl such as 1,4- or 1,3-cyclohexanediyl or a bivalent aromatic radical having 6 to 12 carbon atoms, p is a number chosen such that the polyester unit of the formula (XI) has a molecular weight of 1000 to 2000, and q is 0 or 1. 22." . .