Abstract: The invention relates to a continuous or discontinuous method for the production of highly condensed polyesters in the solid state, comprising a crystallization of a polyester material, wherein the crystallization is carried out in the presence of a gas with a dew point of (less than or equal to) ?approximately ?10° C. The invention also relates to a method for the production of polyester formed bodies using the polyester material obtained for the production of bottles, films and high strength threads.

Abstract: The present invention relates to a method for producing solid-state polycondensed polyesters by using crystallization with or without subsequent solid-state polycondensation for producing bottles, sheets, films, and high-tenacity technical filaments.

Abstract: The invention relates to a continuous or discontinuous method for the production of highly condensed polyesters in the solid state, comprising a crystallisation of a polyester material, wherein the crystallisation is carried out in the presence of a gas with a dew point of (less than or equal to) ?approximately ?10° C. The invention also relates to a method for the production of polyester formed bodies using the polyester material obtained for the production of bottles, films and high strength threads.

Abstract: The present invention relates to a method for producing solid-state polycondensed polyesters by using crystallization with or without subsequent solid-state polycondensation for producing bottles, sheets, films, and high-tenacity technical filaments.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic, titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.25 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 245 to 260° C. as well as a pressure of 1 to 3.5 bar are adjusted. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm. For generating the vacuum in the polycondensation and in the precondensation, there are used vapor jet pumps operated with TMG vapor.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 5.0 bar, preferably 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.

Abstract: According to the invention, a polytrimethylene terephthalate is provided having 0.6 to less than 2 mole percent dipropylene glycol. Such compositions have a reduced tendency to generate acrolein when heated in air. These PTT polymer compositions exhibit improved and enhanced dyeability as compared to conventional PTT made by the DMT process and the TPA polycondensation/solid state polymerization processes.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.

Abstract: According to the invention, a polytrimethylene terephthalate is provided having 0.6 to less than 2 mole percent dipropylene glycol. Such compositions have a reduced tendency to generate acrolein when heated in air. These PTT polymer compositions exhibit improved and enhanced dyeability as compared to conventional PTT made by the DMT process and the TPA polycondensation/solid state polymerization processes.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The sterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.15 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 240 to 275° C., and a pressure of 1 to 3.5 bar are used. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm.

Abstract: Process for purification of essentially oxygen-free process gases by catalytic oxidation of the oxidizable, mainly organic impurities with the addition of a oxygen-containing gas, where oxygen-containing gas is added to the process gas in an amount responsive to the carbon monoxide content of the process gas measured after oxidation. The carbon monoxide set point is in the range of 10 to 1000 vpm.