Catalyst for polyester polycondensation and method for producing polyester resin using the same

A process for producing a polyester resin, comprising:

• mixing one or more dicarboxylic acids and/or ester-forming derivatives thereof with one or more diols to form a mixture;
• subjecting the mixture to an esterification reaction or a transesterification reaction to produce a polyester;
• and
• subjecting the polyester to a melt polycondensation reaction to produce the polyester resin;
• wherein a polycondensation catalyst is added at any stage of the mixing, at any stage of the esterification or transesterification reaction, or at an initial stage of the melt polycondensation reaction;
• and
• wherein the polycondensation catalyst comprises titanium atoms, alkaline earth metal atoms, phosphorus atoms, and carbon atoms, such that:
• at least part of the carbon atoms are derived from an organic acid and/or a carboxylato,
• the content of the titanium atoms T, on weight basis, is 4-20% by weight, and
• the content of the organic acid and/or carboxylato L, on mole basis, the content of the alkaline earth metal atoms M, on mole basis, the content of the titanium atoms T, on weight basis, the content of the phosphorus atoms P, on mole basis, and the content of the carbon atoms C, on weight basis, satisfy expressions (1), (2), and (3):
• 0.8≦L/M(molar ratio)≦1.8 (1)
• 0.05≦T/C(weight ratio)≦0.50 (2)
• 0.5≦M/P(molar ratio)≦3.0 (3).

A process for producing a polyester resin, comprising:

• mixing one or more dicarboxylic acids and/or ester-forming derivatives thereof with one or more diols to form a mixture;
• subjecting the mixture to an esterification reaction or a transesterification reaction to produce a polyester;
• and
• subjecting the polyester to a melt polycondensation reaction to produce the polyester resin;
• wherein a polycondensation catalyst is added at any stage of the mixing, at any stage of the esterification or transesterification reaction, or at an initial stage of the melt polycondensation reaction;
• and
• wherein the polycondensation catalyst is obtained by mixing an alcohol, an alkaline earth metal compound and an acid phosphoric ester compound to form a liquid mixture, and then mixing a titanium compound with said liquid mixture.

A process for producing a polyester resin, comprising:

• mixing one or more dicarboxylic acids and/or ester-forming derivatives thereof with one or more diols to form a mixture;
• subjecting the mixture to an esterification reaction or a transesterification reaction to produce a polyester;
• and
• subjecting the polyester to a melt polycondensation reaction to produce the polyester resin;
• wherein a liquid catalyst solution is added at any stage of the mixing, at any stage of the esterification or transesterification reaction, or at an initial stage of the melt polycondensation reaction;
• and
• wherein the liquid catalyst solution comprises ethylene glycol and/or 1,4-butanediol, and further comprises a polycondensation catalyst comprising titanium atoms, alkaline earth metal atoms, phosphorus atoms, and carbon atoms, such that:
• at least part of the carbon atoms are derived from an organic acid and/or a carboxylato,
• the content of the titanium atoms T, on weight basis, is 4-20% by weight, and
• the content of the organic acid and/or carboxylato L, on mole basis, the content of the alkaline earth metal atoms M, on mole basis, the content of the titanium atoms T, on weight basis, the content of the phosphorus atoms P, on mole basis, and the content of the carbon atoms C, on weight basis, satisfy expressions (1), (2), and (3):
• 0.8≦L/M(molar ratio)≦1.8 (1)
• 0.05≦T/C(weight ratio)≦0.50 (2)
• 0.5≦M/P(molar ratio)≦3.0 (3).