Abstract: There is described a process for preparing a biodegradable polyester from an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid and a diol where in a first reaction step the aromatic acid is esterified with the diol, and in a second reaction step the aliphatic acid is added to the reaction mixture. Furthermore, there is described an apparatus for carrying out this process.

Abstract: A process for reducing the amount of hydroxyl-end-groups of a polyester, wherein the polyester is prepared from at least one dicarboxylic acid and at least one dihydroxy alcohol, and at least one additive selected from the group consisting of carboxylic acid anhydride and mono-isocyanate, and wherein the additive is added during a step of prepolycondensation and/or during a step of polycondensation and/or after a step of polycondensation.

Abstract: A process and a system for producing polyethylene terephthalate (PET) granules by transesterification of dimethyl terephthalate with ethylene glycol or by esterification of (fiber) purified terephthalic acid with ethylene glycol suitable for further processing to form packaging films and bottles, comprising the steps of polycondensation, granulation and latent heat crystallization, aftertreatment of the crude granules to adjust the polymer quality values required for the further processing, in particular the intrinsic viscosity, the acetaldehyde content and the moisture content, wherein the aftertreatment is carried out in multiple moving bed tubular reactors operated in parallel.

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: 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: 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 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 terephtalate as well as reactors and devices that are suited for the application in this method.

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: 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 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: In the continuous production of polyesters, the esterification/transesterification of dicarboxylic acids or esters of the dicarboxylic acids with diols is performed in at least one reaction stage, the prepolycondensation of the esterification/transesterification product is performed under a vacuum in a reaction stage consisting of a vertical tube, and the polycondensation of the prepolycondensation product is performed in at least one reaction stage.

Abstract: A method is described for the manufacture of polyesters of aromatic dicarboxylic acids with aliphatic and/or cycloaliphatic dials, in which an aromatic dicarboxylic acid in the presence of a monocarboxylic acid or a mixture of a monocarboxylic acid present in a saturated solution with water or another suitable solvent is converted with an aliphatic or cycloaliphatic dial to a dicarboxylic acid alkanediolestercarboxylate and/or its oligomers, which are polycondensed in further process steps to the polyester.

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: In a process for producing polyester, the esterification of dicarboxylic acids and diols is carried out in at least one reaction stage, the prepolycondensation of the esterification product in at least one reaction stage and the polycondensation of the prepolycondensation product in at least one reaction stage. To increase the capacity of the apparatus forming one or more of the reaction stages in the production of the polyesters, at at least one of the reaction stages the supplied product system before it enters the reaction stage or within the reaction stage is divided into at least two partial streams and the partial streams entirely or partially separate from one another are passed through the reaction stage.

Abstract: A method is described for the manufacture of polyesters of aromatic dicarboxylic acids with aliphatic and/or cycloaliphatic dials, in which an aromatic dicarboxylic acid in the presence of a monocarboxylic acid or a mixture of a monocarboxylic acid present in a saturated solution with water or another suitable solvent is converted with an aliphatic or cycloaliphatic dial to a dicarboxylic acid alkanediolestercarboxylate and/or its oligomers, which are polycondensed in further process steps to the polyester.

Abstract: In a method for the continuous pre-polycondensation of esterification/transesterification products the stream freely passes from top to bottom in a vertical reaction apparatus through a plurality of attached, heatable, sloped open-above bases, through product overflow channels connected with each other. In order to be able to set a determined, efficient as possible product level in the channels, the esterification/transesterification products are fed though closed, annular-type, concentric annular channels or through parallel channels, wherein a partial quantity of the product stream flowing in the channel is discharged at the product overflows and the remaining product stream is passed via drainage openings.

Abstract: In the continuous production of polyesters, the esterification/transesterification of dicarboxylic acids or esters of the dicarboxylic acids with diols is performed in at least one reaction stage, the prepolycondensation of the esterification/transesterification product is performed under a vacuum in a reaction stage consisting of a vertical tube, and the polycondensation of the prepolycondensation product is performed in at least one reaction stage.

Abstract: In a process for producing polyester, the esterification of dicarboxylic acids and diols is carried out in at least one reaction stage, the prepolycondensation of the esterification product in at least one reaction stage and the polycondensation of the prepolycondensation product in at least one reaction stage. To increase the capacity of the apparatus forming one or more of the reaction stages in the production of the polyesters, at at least one of the reaction stages the supplied product system before it enters the reaction stage or within the reaction stage is divided into at least two partial streams and the partial streams entirely or partially separate from one another is passed through the reaction stage.

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.