The present disclosure provides a Lewis acid-base pair catalytic initiator and an application thereof. The Lewis acid-base pair catalytic initiator includes a Lewis acid and a Lewis base, the Lewis acid having a structural general formula as shown in formula (I) and the Lewis base having a structural general formula as shown in formula (II); wherein: the A is selected from element Baron or element Aluminum; the R.sub.1, R.sub.2, R.sub.3, R.sub.4 are independently selected from alkyl, alkoxy, aryl or halogen groups; the alkyl or alkoxy have a carbon number being equal to or greater than 1 to equal to or less than 16; the aryl contains substituents with the number being equal to or less than 5, the substituents being selected from methyl, methoxy or halogen; n is selected from an integer from 1 to 16.

The present disclosure provides a Lewis acid-base pair catalytic initiator and an application thereof. The Lewis acid-base pair catalytic initiator includes a Lewis acid and a Lewis base, the Lewis acid having a structural general formula as shown in formula (I) and the Lewis base having a structural general formula as shown in formula (II); wherein: the A is selected from element Baron or element Aluminum; the R.sub.1, R.sub.2, R.sub.3, R.sub.4 are independently selected from alkyl, alkoxy, aryl or halogen groups; the alkyl or alkoxy have a carbon number being equal to or greater than 1 to equal to or less than 16; the aryl contains substituents with the number being equal to or less than 5, the substituents being selected from methyl, methoxy or halogen; n is selected from an integer from 1 to 16.

A catalyst composition for a polyester manufacturing process, comprising a titanium catalyst and/or an antimony catalyst as main catalyst, and either (i) at least one co-catalyst A, or (ii) at least one co-catalyst Band at least one co-catalyst C, or (iii) a combination thereof, and wherein co-catalyst A is selected from the group consisting of a metal salt of an alkyl or an aryl phosphinic acid, or a metal salt of an alkyl or aryl diphosphinic acid, or a combination thereof, and co-catalyst B is selected from the group consisting of an alkyl or aryl phosphinic acid, an alkyl or aryl diphosphinic acid a combination thereof, and co-catalyst C selected from the group of a metal salt, a metal hydroxide or a metal organyl compound.

A catalyst composition for a polyester manufacturing process, comprising a titanium catalyst and/or an antimony catalyst as main catalyst, and either (i) at least one co-catalyst A, or (ii) at least one co-catalyst Band at least one co-catalyst C, or (iii) a combination thereof, and wherein co-catalyst A is selected from the group consisting of a metal salt of an alkyl or an aryl phosphinic acid, or a metal salt of an alkyl or aryl diphosphinic acid, or a combination thereof, and co-catalyst B is selected from the group consisting of an alkyl or aryl phosphinic acid, an alkyl or aryl diphosphinic acid a combination thereof, and co-catalyst C selected from the group of a metal salt, a metal hydroxide or a metal organyl compound.

Provided is a polyester resin having excellent adhesiveness and excellent grindability. One aspect of the polyester resin of the present invention is a polyester resin including a constitutional unit A derived from a carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups and a constitutional unit derived from a dicarboxylic acid, in which the constitutional unit A has a content of 0.01 parts by mole or more and 45 parts by mole or less with respect to 100 parts by mole of the constitutional unit derived from a dicarboxylic acid.

Provided is a polyester resin having excellent adhesiveness and excellent grindability. One aspect of the polyester resin of the present invention is a polyester resin including a constitutional unit A derived from a carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups and a constitutional unit derived from a dicarboxylic acid, in which the constitutional unit A has a content of 0.01 parts by mole or more and 45 parts by mole or less with respect to 100 parts by mole of the constitutional unit derived from a dicarboxylic acid.

A catalyst composition for a polyester manufacturing process, comprising a titanium catalyst and/or an antimony catalyst as main catalyst, and either (i) at least one co-catalyst A, or (ii) at least one co-catalyst B and at least one co-catalyst C, or (iii) a combination thereof, and wherein co-catalyst A is selected from the group consisting of a metal salt of an alkyl or an aryl phosphinic acid, or a metal salt of an alkyl or aryl diphosphinic acid, or a combination thereof, and co-catalyst B is selected from the group consisting of an alkyl or aryl phosphinic acid, an alkyl or aryl diphosphinic acid a combination thereof, and co-catalyst C selected from the group of a metal salt, a metal hydroxide or a metal organyl compound.

A catalyst composition for a polyester manufacturing process, comprising a titanium catalyst and/or an antimony catalyst as main catalyst, and either (i) at least one co-catalyst A, or (ii) at least one co-catalyst B and at least one co-catalyst C, or (iii) a combination thereof, and wherein co-catalyst A is selected from the group consisting of a metal salt of an alkyl or an aryl phosphinic acid, or a metal salt of an alkyl or aryl diphosphinic acid, or a combination thereof, and co-catalyst B is selected from the group consisting of an alkyl or aryl phosphinic acid, an alkyl or aryl diphosphinic acid a combination thereof, and co-catalyst C selected from the group of a metal salt, a metal hydroxide or a metal organyl compound.

The invention relates to the synthesis method of polyglycolic acid (PGA) obtained by removing the excessive water and monomer formed subsequent to condensation by means of an organic solvent and using azeotropic distillation method in the presence of a catalyst. The invention is a synthesis method of polyglycolic acid with high molecular weight and high solubility, characterized by comprising the steps of placing the glycolic acid in reaction medium with a catalyst; using hydrophilic organic solvents for removing the excessive water and monomer formed during condensation; mixing and boiling the mixture; stabilizing the amount of solvent in reaction medium and distilling the water off by means of Dean stark apparatus and/or a similar apparatus; refluxing the solid polymer obtained at the end of the reaction with ethyl acetate and removing the same from monomer residue and catalyst.

The invention relates to the synthesis method of polyglycolic acid (PGA) obtained by removing the excessive water and monomer formed subsequent to condensation by means of an organic solvent and using azeotropic distillation method in the presence of a catalyst. The invention is a synthesis method of polyglycolic acid with high molecular weight and high solubility, characterized by comprising the steps of placing the glycolic acid in reaction medium with a catalyst; using hydrophilic organic solvents for removing the excessive water and monomer formed during condensation; mixing and boiling the mixture; stabilizing the amount of solvent in reaction medium and distilling the water off by means of Dean stark apparatus and/or a similar apparatus; refluxing the solid polymer obtained at the end of the reaction with ethyl acetate and removing the same from monomer residue and catalyst.