| 摘要 |
1327711 Polyesters TEIJIN Ltd 19 April 1971 [19 March 1970] 24713/71 Heading C3R Substantially linear highly polymerized polyesters derived from a component glycol and a dicarboxylic or hydroxycarboxylic acid component are produced by adding to the molten polyester when it has an intrinsic viscosity of at least 0À2, as determined on a 1% solution of the polymer in o-chlorophenol at 35%, of an aromatic orthocarbonate having the general formula C(OR) 4 in which each of the groups R may be the same or different is a monovalent aromatic group having a molecular weight not exceding 250 and comprising a benzenoid or naphthalenoid nucleus, and maintaining the polyester in the molten state under a subatmospheric pressure to effect further polycondensation thereof, R may be unsubstituted or may carry one or more aliphatic hydrocarbyl-, alicyclic hydrocarbyl-, aromatic hydrocarbyl-, halogen, nitro-, alkoxy- or aryloxy groups numerous examples of suitable compounds being given. A small amount of a monofunctional compound, e.g. benzoic acid, benzoyl benzoic acid or an alkoxy polyalkylene glycol, or trifunctional or more highly functional compound, e.g. glycerine, pentaerythritol, benzene tetracarboxylic acid, hydroxyisophthalic acid or pyromellitic acid may be copolymerized into the polyester. The aromatic ortho-carbonate may be added to the polyester during the polycondensation at a stage at which its intrinsic viscosity has reached at least 0À2, or a solid preformed polyester of intrinsic viscosity at least 0À2 may be melted, the aromatic orthocarbonate added to the melt and the polyester subjected to further polycondensation. In the examples glycol esters are produced by ester-exchange reactions of dimethyl terephthalate optionally in admixture with dimethyl isophthalate, dimethyl napthalene-2,6-dicarboxylate or ethyl p(#-hydroxyethoxy) benzoate with ethylene glycol, dimethyl terephthalate with trimethylene glycol or cyclohexane dimethanol or dimethyl adipate with hexamethylene glycol in the presence of magnesium, manganese, calcium and cobalt acetates, antimony trioxide and tetraisopropyl and tetrabutyl titanates, or from terephthalic acid and ethylene oxide in the presence of benzene and triethylamine, there being added to the polycondensation compositions trimethyl phosphate, phosphorous acid and titanium tetrabutoxide. |
