Abstract: In a process of producing PBT, a mixture of BDO and TPA is esterified in the presence of a catalyst solution, and the esterification product is polycondensated. To avoid the formation of deposits in the PBT, the catalyst solution contains 0.05 to 10 wt-% alkyl titanate, 85 to 99 wt-% BDO, 50 to 50,000 ppm bifunctional carboxylic acid equivalents and/or monofunctional hydroxycarboxylic acid equivalents and not more than 0.5 wt-% water.

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: Polycarbonates are produced by reacting a monomeric carbonate component with at least one diphenol or dialcohol in the presence of a transesterification catalyst, wherein the molten component is mixed with the transesterification catalyst by stirring and a transesterification product is produced, which is polycondensated. For polycondensation, the transesterification product is passed through a preliminary reactor, at least one intermediate reactor and one final reactor, the reactors being connected in series and having a substantially horizontal driven shaft with stirrers attached thereto. It is ensured that in the preliminary reactor and in the final reactor a dwell time of the melt of 5 minutes to 2 hours is maintained, that the temperatures in the preliminary reactor are maintained in the range from 220 to 300° C. and in the final reactor in the range from 240 to 350° C.

Abstract: Process for producing polyesters and copolyesters, wherein a continuous esterification of dicarboxylic esters and diols or a continuous transesterification of dicarboxylic esters with diols is effected in “n” reaction pressure stages connected in series, the pressure in the first reaction pressure stage is higher than that of the remaining reaction pressure stages, and successively decreases from reaction pressure stage to succeeding reaction pressure stage, the combined vapor flows of the individual reaction pressure stages are rectified in a rectifying column, and the diol component obtained at the bottom of the rectifying column is recirculated at least to the first reaction pressure stage, and wherein at least the last reaction pressure stage operates at a vacuum, the pressure in the rectifying column is greater than that of the last reaction pressure stage, and the vapors discharged from the last reaction pressure stage are condensed to the pressure existing in the rectifying column.

Abstract: A process for the discontinuous production of granules from polycondensation polymers by precondensation of an oligomer at 5 to 400 mbar and subsequent polycondensation in a stirring reactor and subsequent granulation. In the vicinity of the outlet port, the density of the entraining surfaces lies between 1 and 8 m2 per m3 reactor space and constantly increases with increasing distance from the discharge region. Inside the reactor, there is a viscosity gradient between the region most remote from the discharge port and the zone of the discharge port. The thermal decomposition of the polymer melt flowing out of the reactor is compensated during granulation.

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 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: A process for the reduction of the carboxyl end groups of linear polyester through reaction with alkylene carbonate in the melt phase in the presence of 40 to 160 ppm of allyltriphenyl phosphonium bromide, based on the weight of the polyester.

Abstract: An x-ray image intensifier has a housing, an input screen, an output screen, and a number of electrodes for the electron optics, the housing including a number of joined parts and at least one of those parts consisting of electrically insulating material. The part or parts of the housing consisting of insulating material have seating surfaces to which parts, such as the electrodes, are secured by shrinking.

Abstract: An apparatus for processing high viscosity materials consisting of a heatable, horizontal vessel with a product inlet on the one end and a product outlet on the other end and, parallel to the axis of the vessel, a heatable rotating hollow shaft, supporting a plurality of heatable stirrer elements, and between these stirrer elements, fixed to the wall of the vessel, stationary baffle and scraping elements of different configurations.Each stirrer element comprises one to four stirrer wings, each with two hollow spokes and a peripheral, hollow ring-segment connecting the spokes, and fixed to the peripheral end of these ring-segment connections trailing product dragging blades.

Abstract: A process for continuous production of high molecular polybutyleneterephthalate by direct esterification of terephthalic acid and 1,4 butanediol in the presence of tin- or titanium-containing catalysts at preferred temperatures of 235.degree. to 250.degree. C., and preferred pressures of 0.3 to 0.6 bar during the first stage--with minimal formation of tetrahydrofurane--followed by precondensation and polycondensation at reduced pressure.

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.

Abstract: An apparatus and process for removing undesired monomers and oligomers from polyamide melt at subatmospheric pressure by passing steam through the melt to absorb the undesired components and carry them away. Various constructions are disclosed for vigorously intermixing the gas with the melt in which the gas is passed through a foraminous surface over which a thin film of melt flows, and a rotating agitator, spaced less than 50 mm from the surface, mixes the gas with the melt film. In a preferred form of the invention the rotating shaft comprising the agitator carries screw threads and serves as a conveyor for discharging treated melt from the pressure vessel in which the process is carried out.

Abstract: Synthetic-resin bodies, preferably composed of hardenable synthetic resins and especially thermosetting resins are formed by introducing a foamable resin into a mold cavity, setting the foamable resin upon permitting the same to expand to fill the mold cavity, and thereafter introducing into the mold cavity, without changing the volume thereof, at least one additional synthetic resin while the foamed body is plastically deformable but possesses sufficient rupture strength to prevent penetration. The resulting body thus has a surface layer of the second material which displaces the foamed first material.