"wherein R??? is a terephthalic acid group (1,4-C6H4), R??? is an isophthalic acid group (1,3-C6H4), D is a butanediol group (???C4H8-), and D??? is an ethylene glycol group (???C2H4); such that the polymeric backbone contains isophthalic acid ranging from 1 or to 2 to 10 mole % (0.07 to 7 or 7.50 wt. %) and ethylene glycol in an amount ranging from 0.1 to 2 or 10 mole % mole % (0.13 to 1.3 or 2.1" . . . .