Abstract: A process for preparing polyester pellets which involves blending polyethylene terephthalate and polyethylene isophthalate copolymer before solid state polymerization, the polyethylene isophthalate copolymer being composed of dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, palletizing the blend and crystallizing the pellets.

Abstract: The novel polyester (first polyester [A]) of the invention comprises dicarboxylic acid constituent units derived from at least one dicarboxylic acid selected from terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid and diol constituent units derived from diols comprising ethylene glycol and a polyalkylene glycol having a C2-C10 alkylene chain, wherein the proportion of constituent units derived from the polyalkylene glycol is 0.001 to 10% by weight based on the diol constituent units. The polyester [A] has an excellent crystallization rate, is suitably used, singly or as compositions together with another polyester [B] and/or other polymers, for production of molded products such as films, sheets, laminates, preforms and bottles, which have excellent thermal, gas barrier and transparency properties.

Abstract: The present invention provides a catalyst or polyester production capable of producing a polyester with high catalytic activity and a process For producing a polyester using the catalyst. The catalyst for polyester production comprises a solid titanium compound which is obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. The present invention also provides a method to obtain a polyester having a small increase of the acetaldehyde content during the molding. This method comprises bringing a polyester, which is obtained by the use of a titanium compound catalyst and in which the reaction has been completed, into contact with a phosphoric ester aqueous solution or the like having a concentration of not less than 10 ppm in terms of phosphorus atom.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.

Abstract: The present invention provides a polyester resin composition comprising (A) a polyethylene terephthalate composed mainly of repeating units derived from a dicarboxylic acid containing terephthalate acid and/or an esterified derivative thereof and a diol containing ethylene glycol and/or esterified derivative thereof, and (B) an ethylene/(meth) acrylic acid copolymer and, optionally, (C) polyethylene. The polyethylene terephthalate contains diethylene glycol units in a ratio of 0.5 to 2.0% by weight and a cyclic trimer in an amount not greater than 0.5% by weight based on polyethylene terephthalate. The ethylene/ (meth) arcylic acid coploymer is in an amount of 0.1 to 10,000 ppb based on the composition. Also provided are a perform formed from the composition and a blow molded container produced therefrom.

Abstract: A process for preparing a polyester comprising the steps of blending (A) polyethylene terephthalate before solid phase polymerization having an intrinsic viscosity of 0.3 to 0.8 dl/g in an amount of 40 to 99% by weight, with (B) polyethylene naphthalate before solid phase polymerization having an intrinsic viscosity of 0.3 to 0.7 dl/g in an amount of 1 to 60% by weight, and subjecting the blend to solid phase polymerization. The process of the invention can provide a polyester having excellent gas barrier properties, transparency and heat resistance and hardly generating acetaldehyde.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity and a process for producing a polyester using the catalyst. The catalyst for polyester production comprises a solid titanium compound which is obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. The present invention also provides a method to obtain a polyester having a small increase of the acetaldehyde content during the molding. This method comprises bringing a polyester, which is obtained by the use of a titanium compound catalyst and in which the reaction has been completed, into contact with a phosphoric ester aqueous solution or the like having a concentration of not less than 10 ppm in terms of phosphorus atom.

Abstract: A process for preparing a polyester comprising the steps of blending (A) polyethylene terephthalate before solid phase polymerization having an intrinsic viscosity of 0.3 to 0.8 dl/g in an amount of 40 to 99% by weight, with (B) polyethylene naphthalate before solid phase polymerization having an intrinsic viscosity of 0.3 to 0.7 dl/g in an amount of 1 to 60% by weight, and subjecting the blend to solid phase polymerization. The process of the invention can provide a polyester having excellent gas barrier properties, transparency and heat resistance and hardly generating acetaldehyde.

Abstract: Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5% by mol and constituent units derived from isophthalic acid are 0.5 to 85% by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5% by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75% by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (°C.)), as measured by a differential scanning calorimeter, satisfies the formula [1/527−0.

Abstract: Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5 % by mol and constituent units derived from isophthalic acid are 0.5 to 85 % by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5 % by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75 % by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (° C.)), as measured by a differential scanning calorimeter, satisfies the formula [1/527-0.

Abstract: A bottle molded from a polyester composition comprising 97 to 99.99% by weight of a polyester and 3 to 0.01% by weight of a polyester elastomer, which bottle exhibits dimensional change ratios of not greater than 5% measured in the height direction of the bottle and also not greater than 5% measured in the wall part diameter direction of the bottle and has an overturning angle of at least 10.degree., when the bottle was subjected to a hot bath test in which the bottle is filled with a beverage containing 2.5 gas volume carbon dioxide at 23.degree. C., stoppered and immersed in sealed condition in a hot bath heated at 70.degree. C. Thus, the bottle retains self-standing property without deformation even after it is filled with a carbonated beverage and subjected to heat sterilization.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.