Abstract: A method is disclosed for producing polymers with a neutral color tone, wherein a blue and red dye are added before entry into the last polyreaction stage, wherein adjustment of a neutral color tone of the polymer, using a total dye concentration in the polymer of no more than 3 ppm and a proportion of the blue dye in the resulting dye mixture of at least 50% by weight, occurs through independent adjustment of a and b color values in the Lab color space by determination of a and b color values of the polymer without addition of dyes, establishment of the total dye concentration depending on the b-value shift to be achieved, establishment of the required mixture ratio of the colors red and blue depending on the a-value shift to be achieved, and metering of the established content of dye mixture into the reaction mixture.

Abstract: The present invention relates to a catalytically active composition that can be used for the production of polyesters. According to the invention, good polyester products can be obtained in this way without having to use antimony components.

Abstract: A continuous process is disclosed for the extraction of monomeric caprolactam and its oligomers as the raw polymer product obtained in the polymerization of polyamide-6 in which no fresh water, but processing water or previously used extraction water is used for the granulation.

Abstract: The invention relates to a continuous method for the direct production of multilayer mold bodies from a highly condensed polyester melt.

Abstract: The present invention relates to an improved method for the esterification of terephthalic acid with 1,4-butanediol, an improved method for the manufacture of polybutylene terephthalate as well as reactors and devices that are suited for the application in this method.

Abstract: A method for the manufacture of crystallized polyesters with or without subsequent solid state polycondensation for the manufacture of bottles, foils, films and technical high-performance fibres, or with or without subsequent dealdehydization for the manufacture of bottles, foils, films and technical high-performance fibres.

Abstract: The present invention relates to mixtures comprising at least one polyester precursor and at least one alkali- and/or alkaline-earth metal salt where the mixture contains at least one phosphonic acid ester of the Formula (I) (RO)OC—R?—PO(OR)2??(I) where independently R represents a group with 1 to 60 carbon atoms and R? represents a group with 1 to 20 carbon atoms. Furthermore, the present invention relates to the polyester compositions which can be produced from the mixtures and to the resulting polyester films.

Abstract: Polyesters such as polyethylene, polypropylene and polybutylene terephthalate are made from melts of precondensates of polyesters by first conducting vapors comprising precondensate components distributed in the form of an aerosol through a polycondensation reactor in which precondensate components are deposited on the reactor wall and in an outlet chamber of the reactor on a separator. Then the deposits are conducted to the unstirred discharge sump. Upper layers of the discharge sump are continuously recirculated in the stirred reactor area and thus subjected to reconversion and further polycondensation.

Abstract: The invention relates to a method and a device for producing vacuum in the production of polyesters and copolyesters; unrectified vapors from at least one esterification or transesterification stage is preferably used as a driving medium in gas jet pumps for producing the vacuum in one or more polycondensation stages.

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: A method and apparatus are disclosed for the recovery of ethylene glycol in a polyethylene terephthalate (PET) production process, in which water accumulating in the esterification reaction is mixed with a process fluid containing 2-methyl-1,3-dioxolane (MDO). The mixing is carried out in a tank arranged upstream of a rectification column. Through the increase in the water content in the fluid, a shift in the reaction equilibrium takes place and consequently a cleavage of the 2-methyl-1,3-dioxolane present into ethylene glycol and acetaldehyde takes place. Following the cleavage reaction, the mixture is fed from the tank into a rectification column, whereby the ethylene glycol produced from the cleavage reaction is returned to the PET production process.

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. The stirring reactor with horizontal longitudinal axis approximately has the shape of a single or double truncated cone. The reactor has rotatable, vertical product entraining surfaces and stationary scrapers between the same.

Abstract: A process for continuous or discontinuous synthesis of elastomeric copolyesters from polybutylene terephthalate (PBT) and polyoxytetramethylene glycol is described in which the tetrahydrofuran (THF) obtained as a byproduct in synthesis of polybutylene terephthalate from 1,4-butanediol is rectified and then reacted by ring-opening polymerization to form polyoxytetramethylene glycol which condenses with the free or esterified carboxyl groups of PBT to form the copolyester, whereby chain termination and catalyst deactivation are accomplished by adding 1,4-butanediol without separating the catalyst.

Abstract: The invention relates to a continuous method for the direct production of multilayer mold bodies from a highly condensed polyester melt.

Abstract: The present invention relates to a catalytically active composition that can be used for the production of polyesters. According to the invention, good polyester products can be obtained in this way without having to use antimony components.

Abstract: The invention relates to a method and a device for producing polyesters such as for example polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate from precondensates. According to said method, vapors comprising precondensate components that are distributed therein in the form of an aerosol are guided through a polycondensation reactor in which precondensate components condense on the reactor wall and on a separator in an exit chamber of the reactor. The condensates are guided to the unstirred discharge sump and the upper layers of the discharge sump are continuously recirculated into the stirred reactor area thereby subjecting them to reconversion and additional polycondensation.

Abstract: A method of making shaped articles from highly condensed polyester melt and especially preforms for the blow molding of food and especially beverage containers. A melt is continuously withdrawn from the polycondensation reactor and is fed to the shape-imparting units, especially a multiplicity of injection-molding machines without solidification between the final reactor and the injection molders and without degassing between the final reactor and the injection molding machines.

Abstract: The invention relates to a method for producing a granulate with a low acetaldehyde content and improved processing properties from a high-viscosity polyester melt, wherein the polyester melt strand is fragmented under water at the highest possible temperature, the accompanying water is separated from the granulate with the least possible cooling of the granulate, the low-water granulate obtained in this way is passed after removal of the water directly into a dealdehydisation container and the granulate in the dealdehydisation container is treated with a flow of rinsing air, plus a device for carrying out this method.

Abstract: The invention relates to a reactor for the treatment of highly viscous plastic melts, comprising a horizontal, cylindrical container (2) with a vapour exhaust and chambers in the region of the melting bath, formed by the arrangement of panel walls, in which annular discs, fixed to a shaft (3) by spokes and serving as stirrer elements (4, 5) may be rotated, whereby, in the cavities of the annular discs (4, 5), two opposing scrapers (6, 7) are fixed to the inside of the container at an offset angle and run past at a small separation from the front faces of the annular discs and the sleeve of the shaft (3). According to the invention, the assembly and disassembly of the shaft and scraper is simplified by connection of the scraper to the inside of the container by means of a positive connection (13, 19).

Abstract: The invention relates to a method for the analysis of refuse objects (2) containing polymers, in particular of carpets, in a recycling plant (1) and an automatic analytical device (7). In order to determine the polymer constituents of the refuse object (2), according to the invention, part of the refuse object (2) is vaporised and examined by a mass spectrometer (18). Using the method according to the invention and the automatic analytical device according to the invention, the refuse objects (2) can be classified for further processing (9, 10, 11) more accurately and more reliably during transport on a conveyor device (6).