GB985936A - Polyester compositions - Google Patents

Abstract

The invention comprises a random linear polyester of at least one 1,3-propane diol of the formula HO-CH2-CRR1-CH2-OH in which R is an alkyl radical containing from 1 to 6 carbon atoms and R1 is hydrogen or an alkyl radical containing from 1 to 6 carbon atoms and the total number of carbon atoms in R and R1 is at least 3 and at least one acid selected from the group consisting of terephthalic acid and isophthalic acid or a random polyester of 2-methyl 1,3-propane diol or 2,2-dimethyl 1,3-propane diol and a mixture of terephthalic acid and isophthalic acid in which the ratio of terephthalic acid to isophthalic acid is in the ratio of 60:40 to 40:60. Also included are copolyesters containing terephthalate units and isophthalate units in a ratio in the range 60:40 to 40:60 and, in addition to the 2:2-alkyl substituted diol units, also ethylene glycol units (35 to 65 mol per cent of the total glycol) or 2,2-bis-[4-(BETA-hydroxyethoxy)phenyl]-propane units (40 to 60 mol per cent of the total glycol). The polyesters obtained can be soluble in toluene, xylene and methyl ethyl ketone, methyl isobutyl ketone, cyclohexanon, dioxane, nitroparaffins, chlorinated hydrocarbons. In examples the reactants and catalysts are heated at 218 DEG C. while passing a stream of nitrogen until ester interchange is complete ("first stage"). The mixture is then heated at 245 DEG C. with gradual reduction of the pressure while distilling off glycol ("second stage"), and finally at 275 DEG C. The reaction mixtures employed are (1) neopentyl glycol, ethylene glycol, dimethyl terephthalate and dimethyl isophthalate with zinc acetate and polymeric ethylene glycol titanate; (3) mixtures of first stage products from ethylene glycol and dimethyl terephthalate and 2-methyl-2-ethyl-1,3-propane diol respectively; (4) 2-methyl-2-propyl-1,3-propane diol and a first stage product from ethylene glycol and a dimethyl terphthalate-dimethyl isophthalate mixture; (5) mixture of second stage products from ethylene glycol and dimethyl isophthalate and 2,2-diethyl-1,3-propane diol and dimethyl terephthalate respectively; (7) mixture of second stage products prepared from dimethyl terephthalate and 2,2-dimethyl-1,3-propane diol and 2,2-diethyl-1,3-propane diol, respectively; (8) a similar mixture to (7) prepared from the isophthalate; (9) 2,2-bis-[4-(BETA-hydroxyethoxy)-phenyl]propane and a first stage product from 2,2-dimethyl-1,3-propane diol with a mixture of terephthalic and isophthalic acids; (10) a mixture as in (9) but using 2-methyl-2-ethyl-1,3-propane diol and 2,2-diethyl-1,3-propane diol; (11) 2-methyl-2-propyl-1,3-propane diol and dimethyl terephthalate; (12) 2-methyl-2-ethyl-1,3-propane diol, 2,2-diethyl-1,3-propane diol and dimethyl terephthalate; (13) 2-methyl-2-ethyl-1,3-propane diol, dimethyl terephthalate and dimethyl isophthalate; (14) neopentyl glycol, dimethyl terephthalate and dimethyl isophthalate; (15) neopentyl glycol, 2-methyl-2-ethyl-1,3-propane diol, dimethyl terephthalate and dimethyl isophthalate; (16) 2,2-bis-[4 - (BETA - hydroxy - ethoxy)phenyl] propane, 2-methyl-2-ethyl-1,3-propane diol, dimethyl terephthalate zinc acetate and polymeric ethylene glycol titanate.