Abstract: Disclosed is a method for the preparation of a polyester, which method comprises in a first step, reacting a dicarboxylic acid or a C1-C4 dicarboxylic diester with a diol at a suitable temperature and pressure to effect esterification or transesterification to prepare a precondensate and in a second step, reacting the precondensate to effect polycondensation at a suitable temperature and pressure to prepare a high molecular weight polyester, where a metal phosphonic acid complex compound of the formula is employed in the first step, in the second step or in both the first and second steps as a reaction catalyst.

Abstract: Disclosed is a method for the preparation of a polyester, which method comprises in a first step, reacting a dicarboxylic acid or a C1-C4 dicarboxylic diester with a diol at a suitable temperature and pressure to effect esterification or transesterification to prepare a precondensate and in a second step, reacting the precondensate to effect polycondensation at a suitable temperature and pressure to prepare a high molecular weight polyester, where a metal phosphonic acid complex compound of the formula is employed in the first step, in the second step or in both the first and second steps as a reaction catalyst; and wherein n is 0, 1, 2, 3, 4, 5 or 6; p is an integer from 1 to 30; M is a metal selected from the group consisting of Li, Na, K, Cs, Be, Ca, Mg, Sr, Ba, Al, Sb, Cd, Mn, Fe, Co, Ni, Cu and Zn; v is the valency of the metal M and is 1, 2 or 3; q is an integer from 1 to 20 where q=2p/v; and R1 is hydrogen, straight or branched chain alkyl of 1 to 36 carbon atoms, straight or branched chain alkeny

Abstract: The present invention is aimed at a method of providing wettability to polyester fibers or filaments, to woven or nonwoven fabrics made therefrom and to resultant articles of manufacture. The method comprises melt extruding a mixture comprising a polyester and one or more additives selected from the group consisting of a) phenylalkyl-oxy-alkyl metal sulfonates of the formula b) alkyl-oxy-alkyl metal sulfonates of the formula c) polyethyleneoxy-alkyl metal sulfonates of the formula d) alkyl-polyethyleneoxy-alkyl metal sulfonates of the formula and e) alkyl-1,2-disulfonate metal sulfonates where m is 0, 1 or 2, n is an integer from 1 to 6, p is an integer from 1 to 16, R is alkyl of 1 to 24 carbon atoms and M is Na, K or Li. into a plurality of fibers or filaments and cooling the fibers or filaments.