Abstract: The invention relates to a partially crystalline polyethylene terephthalate having a degree of polymerization which is greater than 80, particularly greater than 100, produced from a diol component and a dicarboxylic acid component, wherein according to the invention the DSC melting point, when measured with a heating rate of 10° C./Min during the first passage and second passage, is less than the melting temperature (Tm) of a comparable standard polyethylene terephthalate which is dependent upon the comonomer content.

Abstract: The invention relates to a method and to a device for producing a thermoplastic polyester, having the following steps: a) producing polyester pre-polymer particles; b) crystallizing the polyester pre-polymer particles for producing partially crystalline polyester pre-polymer particles; c) heating the partially crystalline polyester pre-polymer particles to a suitable reaction temperature for producing heated polyester pre-polymer particles; d) reacting the heated polyester pre-polymer particles for producing polyester polymer particles having an intrinsic viscosity between 0.70 and 0.95 dl/g. The reaction in step d) takes place in at least one reactor through which the particles flow by means of gravity. The dwell time in the reactor equals between 6 and 30 hours. The particles are supplied at least to step d) at a mass flow of between 40 and 100 t/h. The present invention is characterized in that a settling rate of the particles in the reactor equals between 2 and 6 m/h.

Abstract: The method of degassing is performed in a ring extruder wherein at least one process chamber is provided with at least one degassing opening. The radius R of the conveyor element in the degassing zone is smaller by ?R than the full radius Rv of the conveyor element required for the mutual stripping of adhering product in a closely intermeshing screw operation with adjacent conveyor elements.

Abstract: The invention relates to a method for producing a high-molecular polyester from a solidified polyester prepolymer by solid phase polycondensation. The polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned and essentially recycled. According to the invention, the process gas is cleaned by means of an aqueous washing liquid. The invention also relates to an installation for carrying out the inventive method, said installation containing a crystallisation appliance (1) and a reaction appliance (2). A gas outlet (2d) of the reaction appliance (2) is directly or indirectly connected to a gas inlet (3c) in a gas cleaning system (3), and a gas outlet (3d) of the gas cleaning system (3) is connected to a gas inlet (2c) of the reaction appliance (2).

Abstract: The invention relates to a method for producing a semicrystalline polymer, said method comprising the following steps: producing a polymer melt from a crystallizable polymer; shaping particles and solidifying the polymer melt, the step of shaping the particles being carried out before or after solidification; cooling the particles; treating the particles to reduce their tendency to agglomerate; crystallizing the particles. The invention is characterized in that the treatment is carried out by shaking at a temperature T1 which is below the glass transition temperature of the polymer plus 10° C., i.e. T1<Tg+10° C.

Abstract: The method of degassing is performed in a ring extruder wherein at least one process chamber is provided with at least one degassing opening. The radius R of the conveyor element in the degassing zone is smaller by ?R than the full radius Rv of the conveyor element required for the mutual stripping of adhering product in a closely intermeshing screw operation with adjacent conveyor elements.

Abstract: The invention relates to a method for producing a high-molecular polycondensate from a solidified polycondensate prepolymer by solid phase polycondensation. According to said method, the polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned of the polycondensation cleavage products and essentially recycled. According to the invention, the specific energy input is less than 120 kWh/t, preferably less than 110 kWh/t and especially between 70 and 100 kWh/t. The invention also relates to an installation for producing a high-molecular polycondensate, said installation comprising a heating appliance (1), followed by a crystallisation appliance (2), a reaction appliance (4), and a cooling appliance (5).

Abstract: The invention relates to a method for the continuous production of semicrystalline polycondensate pellets. Said method comprises the following steps: producing a polycondensate material; shaping polycondensate pellets and solidifying the polycondensate melt in a liquid cooling medium, wherein the shaping of the pellets can be carried out prior to or after solidification; separating the pellets from the liquid cooling medium once the polycondensate pellets have cooled down to an average temperature that lies within the crystallization temperature range of the polycondensate; and crystallizing the pellets in a treatment chamber, the treatment gas being led in said treatment chamber in a countercurrent to the polycondensate pellets, the flow rate of the treatment gas being above the incipient fluidization point of the polycondensate pellets and the polycondensate pellets having a narrow dwell time spectrum in the treatment chamber.

Abstract: The invention relates to a multiple-screw extruder that comprises a first process chamber (1) and a second process chamber (2). In the degassing zones of said extruder, at least the first process chamber is provided with at least one degassing opening. The radius R of the conveyor element in the degassing zones, in at least one conveyor element (7; 9) of at least one screw (5, 7; 5, 9) configured as a passage screw, in a subsection configured as a passage subsection (71a, 71e; 91a, 91e), along the peripheral direction of the at least one conveyor element (7; 9) is by ?R smaller than the full radius Rv of the conveyor element (6; 8) required for the mutual stripping of adhering product in a closely intermeshing screw operation with die adjacent conveyor elements (6; 8) of adjacent conventional screws (5, 6; 5, 8).

Abstract: The method for the production of a polyester with improved melting properties and crystallisation properties comprises the steps of (a) production of a pre-polyester melt with an average molecular weight (Mn) of 2000 to 16000 g/mol, (b) solidifying and shaping the melt into pre-polyester particles, and (c) thermally treating the pre-polyester particles in a solid phase in the presence of a transesterification catalyst whereby a molecular weight increase (?Mn) of more than 2000 g/mol occurs. In addition, the prepolyester particles have a carboxyl end group content (XCOOH) of between 0.25 and 0.6 before step c and during the thermal treatment step c, the proportion of the esterification reaction (E) to the polycondensation reaction (E+T) is between 0.5 and 1.

Abstract: The invention relates to a method and a device for producing spherical particles from a melted mass of plastic. According to the invention, said melted mass is transformed into droplets by means of a droplet-forming nozzle (10); after falling a certain distance, the droplets are crystallised at least on the surface thereof; the droplets are then supplied to a crystallisation stage in which they are fully crystallised; and are then supplied to an postcondensation stage wherein solid phase polycondensation takes place. In order to ensure surface crystallisation without the risk of adhesion both among the drops and to parts of the device, the drops fall in a crystallisation stage (45) having a cloth element or a sheet metal element comprising openings or a fluidised bed chamber through which gas flows in order to swirl the drops.

Abstract: The invention relates to a method for producing a high-molecular polycondensate from a solidified polycondensate prepolymer by solid phase polycondensation. According to said method, the polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned of the polycondensation cleavage products and essentially recycled. According to the invention, the specific energy input is less than 120 kWh/t, preferably less than 110 kWh/t and especially between 70 and 100 kWh/t. The invention also relates to an installation for producing a high-molecular polycondensate, said installation comprising a heating appliance (1), followed by a crystallisation appliance (2), a reaction appliance (4), and a cooling appliance (5).

Abstract: The invention relates to a method for producing a high-molecular polyester from a solidified polyester prepolymer by solid phase polycondensation. The polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned and essentially recycled. According to the invention, the process gas is cleaned by means of an aqueous washing liquid. The invention also relates to an installation for carrying out the inventive method, said installation containing a crystallisation appliance (1) and a reaction appliance (2). A gas outlet (2d) of the reaction appliance (2) is directly or indirectly connected to a gas inlet (3c) in a gas cleaning system (3), and a gas outlet (3d) of the gas cleaning system (3) is connected to a gas inlet (2c) of the reaction appliance (2).

Abstract: The invention relates to a method and installation for carefully producing injection molded parts made of thermoplastic materials at high rates. The invention also relates to a method and installation for carefully producing injection molded parts made of thermoplastic materials while involving the simultaneous homogeneous incorporation of additives or the compounding of plastic mixtures. Finally, the invention relates to an installation that enables the continuously running plasticizing step in a multiple-screw extruder (11; 31) to be economically combined with the intermittently running injection molding process.

Abstract: The invention relates to a partially crystalline polyethylene terephthalate having a degree of polymerization which is greater than 80, particularly greater than 100, produced from a diol component and a dicarboxylic acid component, wherein according to the invention the DSC melting point, when measured with a heating rate of 10° C./Min during the first passage and second passage, is less than the melting temperature (Tm) of a comparable standard polyethylene terephthalate which is dependent upon the comonomer content.

Abstract: The invention relates to a method for production of a partly-crystalline polycondensate, in particular, a polyester or a polyamide, whereby a polycondensate prepolymer is firstly produced, which is prepared and formed into granules, by means of a die-face granulating device, with an average diameter of less than 2 mm, said granules being cut at the outlet from the die plate. The degree of crystallisation and the molecular weight are then increased in a solid-phase polycondensation process. For granulation, the polycondensate prepolymer melt is pressed through a die plate with a number of die perforations, preferably arranged on at least one annular track. The cutting is achieved by means of a circulating knife with a liquid jet.

Abstract: Methods are disclosed herein to reduce and/or eliminate agglomerations and deformations of pellets comprised of crystallizable thermoplastic polymer material during a crystallization or crystallization of the pellets.

Abstract: The invention relates to a method for producing a shaped body, particularly a profiled piece, from a polycondensate, particularly a polyester such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT) or one of the copolymers thereof. According to the invention, the polycondensate is melted over the course of the method and, later, is rendered solid once again. The invention is characterized in that the total time, during which the temperature of the polycondensate over the course of the method is higher than the melting temperature of the polycondensate, is less than approximately 60 seconds. The method is preferably carried out by means of a multiple screw extruder, whereby the degassing and/or drying of the polycondensate ensues in the solid state at a pressure less than the atmospheric pressure and/or while adding an inert gas.

Abstract: The invention relates to a multi-shaft extruder for the continuous treatment and/or processing of bulk material, especially a powdery, granular or flocculent product, comprising a plurality of shafts (3) which are arranged in a crown-like manner in a cavity (1) of an extruder housing (2), said shafts extending parallel to the axial direction (A) of the extruder and forming an inner processing chamber (1a) inside the crown, and an outer processing chamber (1b) outside the crown. Each shaft carries a number of axially successive processing elements (4), at least part of the same being elements (4a; 4c; 4e) having a transporting effect, and with which adjacent shafts engage in a sealed manner at least in partial regions.

Abstract: The invention relates to a method for producing a polyester hollow body or its preform with a reduced acetaldehyde content from a drop-shaped, globular or spherical polyester granulate with a granulate diameter of less than 2 mm. Said method is characterised in that the molecular weight of the polyester in the production step of melt-phase polymerisation is set to an intrinsic viscosity (IV) value of 0.15 to 0.4 dl/g, the melt is transferred to a drop-shaped, globular or spherical mould by drop-processing and subsequently solidifies, the molecular weight of the polyester in the production step of solid-phase polycondensation is increased to an IV value of greater than 0.65 dl/g and the polyester material that has been treated in this manner is shaped by being introduced into shaping means, to form the hollow body or its preform. The shaping process can be carried out by injection moulding, sintering or extrusion blow moulding.