Abstract: A polyester composition comprising 99.9 to 80 wt % of a thermoplastic polyester containing an antimony compound and 0.1 to 20 wt % of a partially aromatic polyamide, wherein a 4 mm-thick molded plate formed by molding the thermoplastic polyester at 290° C. has a haze value of 10% or lower, and wherein the phosphorus atom content in the partially aromatic polyamide (P1), the partially aromatic polyamide content in the polyester composition (A), and the antimony atom content in the thermoplastic polyester (S) satisfy a specific formula, wherein a 4 mm-thick molded plate produced by molding the polyester composition at 290° C. has a haze value of 20% or lower. The polyester composition can be molded into a hollow molded article (e.g., a bottle) at a high productivity rate, which is not deteriorated in transparency or color, and which is excellent in flavor-conserving property, thermal stability and gas-barrier property.

Abstract: A polyester resin that can be beneficially employed as one finding application in deactivation of polycondensation catalysts for polyester production and suppression of forming of acetaldehyde and other aldehydes and cyclic ester oligomers at molding stage. In particular, there is provided a polyester resin composed mainly of an aromatic dicarboxylic acid component and a glycol component wherein a phosphorus compound is incorporated through copolymerization or blending in an amount of 100 to 10,000 ppm in terms of phosphorus element, characterized in that the contents of Zn element, Fe element, Ni element and Cr element are not greater than specified values.

Abstract: The invention is a polyester resin mainly comprising a terephthalic acid component and a glycol component, wherein the fluorescence spectrum obtained by irradiating the polyester resin with excited light having a wavelength of 343 nm has a fluorescence intensity at 450 nm (B0) of 20 or lower. The resin makes it possible to efficiently produce a shaped article, especially a heat-resistant blow-molded article, that has excellent transparency and a moderate and stable crystallization rate and excellent heat-resistance dimensional stability, and is prevented from emitting fluorescence when irradiated with UV rays, and which is excellent in long-run continuous workability with no mold contamination, and which provides a wrapping material having excellent flavor retentiveness.

Abstract: This invention provides a novel polymerization catalyst other than antimony compounds, polyester produced by using the same and a process for producing polyester. The polycondensation catalyst of this invention is a polyester polymerization catalyst comprising an aluminum compound and a phosphorus compound having a specific structure. Further, this invention relates to polyester produced by using this polyester polymerization catalyst and a process for producing polyester. Further, this invention relates to fibers, films and hollow molded articles comprising the polyester.

Abstract: A polymerization catalyst for polyester production which contains neither a germanium compound nor an antimony compound as a major component. It contains aluminum as the main metallic ingredient, has excellent catalytic activity, and gives a polyester which is effectively inhibited from suffering thermal degradation, during melt molding, without deactivating or removing the catalyst, and is excellent in thermal stability, stability to thermal oxidation, and hydrolytic resistance. The polymerization catalyst contains as a first metallic ingredient at least one member selected among aluminum and compounds thereof and further contains a phosphorus compound represented by a specific chemical formula. The polyester produced with this catalyst is usable as fibers, films, sheets, various moldings including hollow moldings, etc.

Abstract: A polymerization catalyst for polyester production which contains neither a germanium compound nor an antimony compound as a major component. It contains aluminum as the main metallic ingredient, has excellent catalytic activity, and gives a polyester which is effectively inhibited from suffering thermal degradation, during melt molding, without deactivating or removing the catalyst, and is excellent in thermal stability, stability to thermal oxidation, and hydrolytic resistance. The polymerization catalyst contains as a first metallic ingredient at least one member selected among aluminum and compounds thereof and further contains a phosphorus compound represented by a specific chemical formula. The polyester produced with this catalyst is usable as fibers, films, sheets, various moldings including hollow moldings, etc.

Abstract: This invention provides a novel polymerization catalyst other than antimony compounds, polyester produced by using the same and a process for producing polyester. The polycondensation catalyst of this invention is a polyester polymerization catalyst comprising an aluminum compound and a phosphorus compound having a specific structure. Further, this invention relates to polyester produced by using this polyester polymerization catalyst and a process for producing polyester. Further, this invention relates to fibers, films and hollow molded articles mprising the polyester.

Abstract: A polyester resin comprising a polyester resin chip (A) and a polyester resin fine particle (B) which has the same composition as the (A) and which passes through a 10.5 mesh screen in a proportion of 0.1-300 ppm, wherein a cyclic trimer increases in a proportion of not more than 0.30 wt % upon melting at a temperature of 290.degree. C. for 60 minutes; a polyester resin characterized in that a cyclic trimer increases in a proportion of not more than 0.30 wt % upon melting at a temperature of 290.degree. C. for 60 minutes, and the contents of Na, Ca, Mg and/or Si in the polyeser resin is 0.001-5 ppm and the total of these contents is not more than 10 ppm; and production methods thereof.