Abstract: Disclosed is a process for reducing the self-adhesiveness of polytrimethylene terephthalate pellets, which can be carried out in a continuous or batch manner comprising the steps of: a) introducing polytrimethylene terephthalate pellets having an intrinsic viscosity of at least about 0.4 dl/g into a conduit containing a liquid which is moving through the conduit, thereby causing the pellets to move through the conduit with the liquid; b) adjusting the temperature of the pellets and the liquid to a temperature of about 50 to about 95° C. for a time sufficient to induce a degree of crystallinity of at least about 35% in the pellets; and c) separating the pellets from the liquid.

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: Disclosed is a process for reducing the self-adhesiveness of polytrimethylene terephthalate pellets, which can be carried out in a continuous or batch manner comprising the steps of:

Abstract: Disclosed is a process for reducing the self-adhesiveness of polytrimethylene terephthalate pellets, which can be carried out in a continuous or batch manner comprising the steps of: a) introducing polytrimethylene terephthalate pellets having an intrinsic viscosity of at least about 0.4 dl/g into a conduit containing a liquid which is moving through the conduit, thereby causing the pellets to move through the conduit with the liquid; b) adjusting the temperature of the pellets and the liquid to a temperature of about 50 to about 95° C. for a time sufficient to induce a degree of crystallinity of at least about 35% in the pellets; and c) separating the pellets from the liquid.

Abstract: Disclosed is a process for reducing the self-adhesiveness of polytrimethylene terephthalate pellets, which can be carried out in a continuous or batch manner comprising the steps of:

Abstract: Process for generating a vacuum and separating the condensable components of the vapors of melt-phase polycondensation in the production of polycarbonate, where at least one or two vapor jets with a downstream spray condenser are connected to the intake side of the polycondensation reactor to be evacuated, and the motive vapor is diphenyl carbonate vapor, and the spray liquid is liquid diphenyl carbonate.

Abstract: Process for multi-stage generation of a vacuum and condensation and recycling of the vapors of polycondensation in the production of polyester, where the last stage includes a liquid ring pump compressing to atmospheric pressure, a cooler and a degasifier tank. The process also includes at least two preceding stages each using a glycol vapor jet that is operated with superheated glycol vapor at a pressure in the range of 0.8 to 1.0 bar abs. and a downstream glycol spray condenser whose operating conditions are regulated to condense a maximum quantity of glycol and at the same time causing the low-boiling reaction by-products including water to remain in the gas phase.

Abstract: Continuous multistep, economical, energy-saving process for making polybutylene terephthalate in which the butanediol-1,4 used to transesterify dimethyl terephthalate is supplied from the condensed vapors volatilized during the precondensation and polycondensation steps of the process. These vapors, which contain low-soluble esters of terephthalic acid as well as butanediol, are condensed by contact with fresh butanediol, and volatilized butanediol containing the esters is recycled to the initial transesterification stage for reaction with dimethyl terephthalate. No additional butanediol is required for the reaction.