Polyester resin composition, process for producing the same, and polyester film
AssigneeToray Industries, Inc.
InventorsYoshihiro Honma, Jun Sakamoto, Masahiro Kimura
Life of this patent
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Abstract
A polyester resin composition having an equivalent spherical diameter of 1 mm to 50 mm, a degree of crystallization of not less than 65% and less than 99%, an intrinsic viscosity of not more than 0.7 dl/g and a cyclic trimer content of not more than 0.4% by weight. This polymer resin composition has an excellent color tone, causes no significant viscosity lowering or viscosity rise, and can withstand a process which is exposed to a long-term thermal history. A polyester resin composition having a viscosity suitable for extrusion in a general-purpose manner, a production process thereof, and a polyester film are also provided.
Claims14
A polyester resin composition having a content of a cyclic trimer is in a range of 0.1 to 0.7% by weight, a content of a carboxylic end group is in a range of 15 to 40 equivalent/ton, an intrinsic viscosity is in a range of 0.55 to 0.80 dl/g, and an absorbance at a wavelength of 365 nm of a solution prepared using orthochlorophenol as a solvent (0.8 g/10 ml) is in a range of 0.22 to 0.36, wherein the polyester resin composition has a content of bis(hydroxyethyl)terephthalate in a range of 90 to 200 ppm.
A process for producing a polyester resin composition wherein a polyester having an intrinsic viscosity of 0.4 to 0.7 dl/g and a degree of crystallization of not less than 30% is heated at a temperature of 190° C. to 250° C. for 0.5 to 60 hours under an inert gas atmosphere having a pressure of 650 to 1,020 hPa to produce a polyester resin composition having a content of a cyclic trimer in a range of 0.1 to 0.7% by weight, a content of a carboxylic end group in a range of 15 to 40 equivalent/ton, an intrinsic viscosity in a range of 0.55 to 0.80 dl/g, and an absorbance at a wavelength of 365 nm of a solution prepared using orthochlorophenol as a solvent (0.8 g/10 ml) in a range of 0.22 to 0.36 wherein the polyester resin composition has a content of bis(hydroxyethyl)terephthalate in a range of 90 to 200 ppm.
Dependencies are inferred from the claim text.