초록 ▼

A method for preparing polyester by use of a catalyst. The method comprises the steps of: esterifying either a terephthalic acid, a dicarboxylic acid containing terephthalic acid or derivatives thereof with either ethylene glycol or a glycol containing ethylene glycol, or derivatives thereof to prod

A method for preparing polyester by use of a catalyst. The method comprises the steps of: esterifying either a terephthalic acid, a dicarboxylic acid containing terephthalic acid or derivatives thereof with either ethylene glycol or a glycol containing ethylene glycol, or derivatives thereof to produce an esterification product containing either bis(.beta.-hydroxyethyl) terephthalate, its low molecular weight polymer, or a combination of .beta.-hydroxyethyl terephthalate and its low molecular weight polymer; and continuously polycondensing the obtained esterification product to prepare a polyester, wherein in the said polycondensing step, a composite polymerization catalyst dissolved in an ethylene glycol or an ethylene glycol-containing solution, consisting of a compound of antimony, a compound of titanium, and a compound of tin is used. The method can considerably reduce both the esterification time and the polycondensation time and provides a good color, reduced content of diethylene glycol and reduced concentration of terminal carboxyl groups in the prepared polyesters.

대표청구항 ▼

[ What is claimed is:] [1.] A method for preparing polyesters, comprising the steps of:esterifying a dicarboxylic acid and a glycol, to produce an esterification product; andcontinuously polycondensing the obtained esterification product to prepare a polyester, wherein during or after said esterifyi

[ What is claimed is:] [1.] A method for preparing polyesters, comprising the steps of:esterifying a dicarboxylic acid and a glycol, to produce an esterification product; andcontinuously polycondensing the obtained esterification product to prepare a polyester, wherein during or after said esterifying step, a composite polymerization catalyst dissolved in glycol is used, said composite polymerization catalyst consisting of:at least one compound of antimony;at least one compound of titanium selected from the group consisting ofa compound represented by formula I EQU (R.sub.1 O).sub.4 Ti.HP(O) (OR.sub.2).sub.2 I rein R.sub.1 and R.sub.2 are the same or different, and are independently selected from the group consisting of an aliphatic group of 1 to 20 carbon atoms, an aromatic aryl group of 6 to 20 carbon atoms,a titanium ester,a monoalkoxy titanate,a titanate chelate,a neoalkoxytitanate, anda heterocyclic titanate; andat least one compound of tin selected from the group consisting of dibutyltin salicylate, dioctyltin diacetate, dibutyltin stearate, dibutyltin maleate, dibutyltin bis(butylmaleate) and dibutyltin bis(isooctylmercaptoacetate).