Abstract: An aliphatic-aromatic polyester resin comprising principal structural units that includes aliphatic dicarboxylic acid units, aromatic dicarboxylic acid units, and aliphatic diol units and/or alicyclic diol units, wherein an abundance ratio (molar ratio) between the aliphatic dicarboxylic acid units and the aromatic dicarboxylic acid units is 15:85 to 85:15; the aliphatic-aromatic polyester resin has a glass transition temperature of ?25° C. or more; and the aliphatic-aromatic polyester resin has branched structures represented by formulae (1) to (4) below: where Ar1, Ar2, and Ar3 each independently represent an optionally substituted divalent group having 4 to 12 carbon atoms, the optionally substituted divalent group being a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group; R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and n, m, and r are each independently an integer of 2 to 10.

Abstract: Provided is a method for producing an aliphatic-aromatic polyester, such as PBST, by an esterification and/or transesterification reaction and a polycondensation reaction, the method being capable of reducing the insufficiency in the degree of crystallization in the related art and capable of producing an aliphatic-aromatic polyester having a high degree of crystallinity. A method for producing an aliphatic-aromatic polyester, the method including subjecting an aliphatic diol component, an aliphatic dicarboxylic acid component, and an aromatic dicarboxylic acid component that serve as raw materials to an esterification and/or transesterification reaction and a polycondensation reaction subsequent to the esterification and/or transesterification reaction in a presence of a catalyst, wherein, while the aliphatic-aromatic polyester is produced, a nucleating agent that satisfies a condition represented by Formula (1) below is present in a reaction system. 0° C.<Tm1?Tm2?100° C. . . .

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: The invention relates to a liquid catalyst solution containing a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost.

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: A process for producing a polyester using a catalyst, which catalyst enables producing a polyester excellent in color tone and transparency at a high reaction velocity; the catalyst; and a method for producing the catalyst, which catalyst comprises: (1) at least one metal element selected from the group consisting of metal elements of Group 4A of the Periodic Table, (2) at least one metal element selected from the group consisting of metal elements of Group 2A of the Periodic Table, aluminum, manganese, iron, cobalt, zinc, gallium and germanium, (a) when the total amount of metal atoms derived from metal element (1) is represented by t (mol/catalyst kg), and the total amount of metal atoms derived from metal element (2) is represented by m (mol/catalyst kg), the value of m/t is within 0.50?m/t?3.50.

Abstract: The invention relates to a liquid catalyst solution containing a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost.

Abstract: The invention provides: a polycondensation catalyst for polyester production, which contains titanium atoms, alkaline earth metal atoms and phosphorus atoms, has high reactivity and excellent long-term storage stability, can be easily produced industrially, and has an advantage in cost; a polyester resin obtained with the catalyst; and a molded article. These are: a polymerization catalyst for polyester production containing titanium atoms, alkaline earth metal atoms and phosphorus atoms and having a specific constitution; a polyester resin obtained with the catalyst; and a molded article.

Abstract: A polymerization catalyst for a polyester, characterized in that it comprises components having at least the following metal element (1) and the following metal element (2), their contents satisfy the following (a), it is in a liquid state with a turbidity of at most 20% in a light path length of 10 mm, and a polyester excellent in color tone and transparency can be produced at a high reaction velocity with it, a method for producing it and a process for producing a polyester using it: (1) at least one metal element selected from the group consisting of metal elements of Group 4A of the Periodic Table, (2) at least one metal element selected from the group consisting of metal elements of Group 2A of the Periodic Table, aluminum, manganese, iron, cobalt, zinc, gallium and germanium, (a) when the total amount of metal atoms derived from the above metal element (1) is represented by t (mol/catalyst kg), and the total amount of metal atoms derived from the above metal element (2) is represented by m (mol/catalyst

Abstract: Polymerization catalysts for polyesters include: (1) metal elements selected from metal elements of Group 4A of the Periodic Table; and (2) metal elements selected from metal elements of Group 2A of the Periodic Table, aluminum, manganese, iron, cobalt, zinc, gallium and germanium. The catalysts are in a liquid state with a turbidity of at most 20% in a light path length of 10 mm, and a ratio the total amount of metal atoms derived from the above metal element (2) to the total amount of metal atoms derived from the above metal element (1) is from 0.50 to 3.50.

Abstract: A polyester resin characterized in that the content of the copolymerized components other than the terephthalic acid component and the ethylene glycol component, is not more than 4 mol % based on the total dicarboxylic acid component, and when polyester resin is formed into a molded product, the molded product has a specific absorbance.

Abstract: A polyester resin produced by polycondensing a dicarboxylic acid component containing an aromatic dicarboxylic acid or its ester-forming derivative as the main component and a diol component containing ethylene glycol as the main component in the presence of at least an antimony compound and a phosphorus compound, via an esterification reaction or an ester exchange reaction, which is characterized in that the amount of antimony eluted when immersed in hot water of 95° C. for 60 minutes in the form of particles having a number average particle weight of 24 mg, is not more than 1 ?g per 1 g of the polyester resin, as antimony atoms (Sb).

Abstract: A polyester resin, whereby a molded product excellent in a gas barrier property and also excellent in an ultraviolet shielding property, a color tone, etc., and which is particularly suitable for molding a bottle for e.g. a beverage required to have an aroma retention property, and further, a polyester resin, whereby the acetaldehyde content as a molded product is reduced to eliminate an influence over the taste, aroma, etc. of the content, and a process for its production, wherein the polycondensability is improved, are to be presented.

Abstract: A polyester resin characterized in that the content of the copolymerized components other than the terephthalic acid component and the ethylene glycol component, is not more than 4 mol % based on the total discarboxylic acid component, and when polyester resin is formed into a molded product, the molded product has a specific absorbance.

Abstract: A polymerization catalyst for a polyester, characterized in that it comprises components having at least the following metal element (1) and the following metal element (2), their contents satisfy the following (a), it is in a liquid state with a turbidity of at most 20% in a light path length of 10 mm, and a polyester excellent in color tone and transparency can be produced at a high reaction velocity with it, a method for producing it and a process for producing a polyester using it: (1) at least one metal element selected from the group consisting of metal elements of Group 4A of the Periodic Table, (2) at least one metal element selected from the group consisting of metal elements of Group 2A of the Periodic Table, aluminum, manganese, iron, cobalt, zinc, gallium and germanium, (a) when the total amount of metal atoms derived from the above metal element (1) is represented by t (mol/catalyst kg), and the total amount of metal atoms derived from the above metal element (2) is represented by m (mol/catalyst

Abstract: A polyester resin produced by polycondensing a dicarboxylic acid component containing an aromatic dicarboxylic acid or its ester-forming derivative as the main component and a diol component containing ethylene glycol as the main component in the presence of at least an antimony compound and a phosphorus compound, via an esterification reaction or an ester exchange reaction, which is characterized in that the amount of antimony eluted when immersed in hot water of 95° C. for 60 minutes in the form of particles having a number average particle weight of 24 mg, is not more than 1 &mgr;g per 1 g of the polyester resin, as antimony atoms (Sb).

Abstract: A polyester resin produced by polycondensing a dicarboxylic acid component containing an aromatic dicarboxylic acid or its ester-forming derivative as the main component and a diol component containing ethylene glycol as the main component in the presence of at least an antimony compound and a phosphorus compound, via an esterification reaction or an ester exchange reaction, which is characterized in that the amount of antimony eluted when immersed in hot water of 95° C. for 60 minutes in the form of particles having a number average particle weight of 24 mg, is not more than 1 &mgr;g per 1 g of the polyester resin, as antimony atoms (Sb).