| 摘要 |
In the manufacture of polymethylene terephthalates by effecting ester-interchange between a dialkyl terephthalate and a glycol of formula HO(CH2)nOH, where n=2-10, in the presence of an alkaline earth metal compound and polycondensing the product in the presence of a polycondensation catalyst, the deposition of insoluble salts is avoided, by adding at the completion of the ester-interchange a substance of formula <FORM:0886966/IV (a)/1> or <FORM:0886966/IV (a)/2> where A is an organic residue, and the P-A linkage is not a phosphorous oxygen linkage, R = hydrogen or alkyl, x and n = 1 or 2 and m = 3 - n. The additives convert the alkaline metal, wholly or in part, to a salt of an acid of sulphur or phosphorus and also become combined with the polymethylene terephthalates thereby giving them improved affinity for basic dyes. The residue A may be aromatic, aliphatic, alicyclic or hetrocyclic. Copolyesters may be obtained by incorporating in the mixture undergoing ester-exchange either a second glycol or a second dialkyl ester (e.g. a di (carboalkoxyphenoxy) alkane). Specified are: Sulphur compounds-3:5-di (carbomethoxy) benzene sulphonic acid, methyl 3:5-di (carbomethoxy) benzene sulphonate, p-carbomethoxy benzene sulphonic acid, 3:5-dicarboxy benzene sulphonic acid and p-carboxy benzene sulphonic acid; Phosphorous compounds-p-carboxy benzene phosphonic acid, di (p-carbomethoxyphenyl) phosphinic acid and methyl di(p-carbomethoxyphenyl) phosphinate; Ester-exchange catalysts-calcium acetate, calcium oxide and barium acetate; Polycondensation catalysts-antimony trioxide, litharge and compounds of germanium, lanthinum or lead. Examples describe the manufacture of polyesters by reacting dimethyl terephthalate with (1)-(12) ethylene glycol; (18) 1:4 butanediol; (19) ethylene glycol and 1:2-di-(p-carbomethoxyphenoxy) ethane. Specifications 742,811, 802,921, 826,248 and 856,917 are referred to.
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