Abstract: A method and a device for the production of polyamide 6 pellets wherein an intermediate drying is not necessary and a combined pelletizing and extraction take place. Depending on the intended use, the pellets may directly be used or subjected to further treatment steps. A device for the production of polyamide 6 pellets includes a melt device for providing a melt of polyamide 6, an underwater pelletizing system which is operable under increased pressure, and a vertical vessel having a cylindrical section and a tapered bottom section. The tapered bottom section is provided with a cooling device and is connected to a pipe comprising a screw and/or a rotary gate valve for conveying pellets. The device includes a circuit for circulating an aqueous solution of ? caprolactam through the underwater pelletizing system and the vertical vessel.

Abstract: The invention relates to a method for producing a plastic granulate (16), in which a process fluid (12) is contained in a process chamber (10) where an underwater granulation takes place and the process fluid in the process chamber has a temperature greater than 120° C. A process pressure of at least 2.0 bar is obtained in the process chamber, at which a granulation of the plastic strands (14) into plastic granulate occurs. From the process chamber, a mixture (18) of process fluid and plastic granulate is diverted into a first cooling zone (25) during cooling of the plastic granulate, while maintaining the process pressure. In a first separating device (22), the plastic granulate is separated from the process fluid under process pressure. In the process chamber, the process fluid has a temperature in the range from 120° C. to 160° C., and the process pressure obtained there is greater than the pressure of the vapour pressure curve of the process fluid.

Abstract: The present invention relates to a method for the production of polyamide 6 with low extract content and a device for it. Here, a melt of non-extracted polyamide 6 is cleaned from monomer and oligomers in a degasification device in vacuum, wherein the vapor being withdrawn from the degasification device by the vacuum generation device is cleaned from monomer, oligomers and optionally water at first in a direct condenser which is operated with liquid ?-caprolactam and subsequently in a pre-separator which is cooled with a coolant, before it reaches the vacuum generation device. A particularly preferable variant of the method envisages the usage of the melt of polyamide 6 with low extract content so prepared in a direct process of spinning into textile fibers and/or filaments.

Abstract: The present invention relates to a method for the production of polyamide 6 with low extract content and a device for it. Here, a melt of non-extracted polyamide 6 is cleaned from monomer and oligomers in a degasification device in vacuum, wherein the vapor being withdrawn from the degasification device by the vacuum generation device is cleaned from monomer, oligomers and optionally water at first in a direct condenser which is operated with liquid ?-caprolactam and subsequently in a pre-separator which is cooled with a coolant, before it reaches the vacuum generation device. A particularly preferable variant of the method envisages the usage of the melt of polyamide 6 with low extract content so prepared in a direct process of spinning into textile fibers and/or filaments.

Abstract: The invention relates to a method for producing a plastic granulate (16), in which a process fluid (12) is contained in a process chamber (10) where an underwater granulation takes place and the process fluid in the process chamber has a temperature greater than 120° C. A process pressure of at least 2.0 bar is obtained in the process chamber, at which a granulation of the plastic strands (14) into plastic granulate occurs. From the process chamber, a mixture (18) of process fluid and plastic granulate is diverted into a first cooling zone (25) during cooling of the plastic granulate, while maintaining the process pressure. In a first separating device (22), the plastic granulate is separated from the process fluid under process pressure. In the process chamber, the process fluid has a temperature in the range from 120° C. to 160° C., and the process pressure obtained there is greater than the pressure of the vapour pressure curve of the process fluid.

Abstract: A method and device for continuously drying and crystallizing water-flushed granulate. The method comprises the steps of: feeding water-flushed granulate into a pre-dryer, pre-drying granulate in the pre-dryer, conveying pre-dried granulate into a dryer/crystallizer, and discharging crystallized granulate from the dryer/crystallizer. An air conditioning means produces temperature-controlled and humidity-conditioned air that is delivered to the dryer/crystallizer, wherein the exhaust air of the dryer/crystallizer is delivered to the pre-dryer, and wherein the exhaust air of the pre-dryer is returned to the air conditioning means forming a closed air circuit is formed by the dryer/crystallizer, pre-dryer, and air conditioning means. The device comprises a pre-dryer, a dryer/crystallizer, an air conditioning means, and optionally a control unit.

Abstract: A method for making granules from a melt material extruded by being pressed through nozzle openings of a perforated plate in a cutting chamber. In this process, the melt material emerging from the nozzle openings of the perforated plate is cut into molten granules in the cutting chamber by at least one rotating cutting knife that sweeps across the nozzle openings. A first coolant flow of a first coolant medium is delivered through a first coolant inlet to at least one first coolant port, with which the melt material is cooled when emerging and being cut at the perforated plate. Furthermore, a second coolant flow of a second coolant medium different from the first is delivered through a second coolant inlet to at least one second coolant port downstream of the perforated plate, with which the granules are additionally cooled and conveyed to an outlet of the cutting chamber.

Abstract: A device and method for producing pellets from a melt material, the device having a perforated plate with nozzles. Located opposite the perforated plate is a cutter arrangement having a cutter head with at least one blade, wherein the device additionally has a cutting chamber in a housing. A coolant is introduced into the cutting chamber from an inlet apparatus, wherein one or more additional feed opening(s) is/are provided for an additional flow of coolant to the cutting chamber. The additional coolant flows at least in the area of rotation of the at least one blade, circumferentially at least in sections, with an orientation such that this additional flow of coolant differs from the flow of coolant entering through the inlet nozzle arrangement in at least one of the following parameters: physical state, direction, speed, pressure, temperature, density, throughput rate, and/or composition.

Abstract: A method and a device for producing superficially crystalline spherical granules by means of air-cooled hot die face pelletizing in a cutting chamber. A crystallizable plastic material can be melted and then extruded through a perforated plate. During the air-cooled hot die face pelletizing, at least one cutting blade can be moved relative to the perforated plate. The perforated plate can be temperature-controlled while maintaining a viscosity of the plastic material within nozzle openings. A superficial cooling to a crystal nucleation temperature of the dry-cut granules is performed by means of a centripetally inflowing process gas. The crystal nucleation temperature is below an optimum crystal growth temperature and above a glass transition temperature. By controlling the quantity of process gas at an adiabatic temperature, an average granule temperature is maintained in a range of an optimum crystal growth temperature.

Abstract: A method and device for continuously drying and crystallizing water-flushed granulate. The method comprises the steps of: feeding water-flushed granulate into a pre-dryer, pre-drying granulate in the pre-dryer, conveying pre-dried granulate into a dryer/crystallizer, and discharging crystallized granulate from the dryer/crystallizer. An air conditioning means produces temperature-controlled and humidity-conditioned air that is delivered to the dryer/crystallizer, wherein the exhaust air of the dryer/crystallizer is delivered to the pre-dryer, and wherein the exhaust air of the pre-dryer is returned to the air conditioning means forming a closed air circuit is formed by the dryer/crystallizer, pre-dryer, and air conditioning means. The device comprises a pre-dryer, a dryer/crystallizer, an air conditioning means, and optionally a control unit.

Abstract: The invention relates to a device for the implementation of a method for the production of pellets of polyamide 6 or copolyamides. The method can include production of a melt of polyamide 6 or copolyamides by means of polymerization, production of pellets from the melt by means of underwater pelletization into a process fluid, removal of the pellets from a site of underwater pelletization in the process fluid, supply of the pellets in the process fluid to an extraction stage, extraction of low-molecular components as extract, and drying of the pellets after extraction, wherein the underwater pelletization stage and the extraction stage take place using the same process fluid.

Abstract: A device and a method for reducing the pressure of a fluid containing granules. The device comprises a free space devoid of moving rotor blades and a housing with an inlet and an outlet. The shape of the wall within the housing and of the free space therein applies a centripetal flow component to the fluid containing the granules flowing therethrough. The pressure of the fluid containing the granules is decreased after the flow has passed through the device. The device and method further and impart a rotational motion to the fluid containing the granules in the area of the outlet, which is generally located in the central area of the free space.

Abstract: A method for continuous casting and granulating strands of a thermoplastic material which uses a nozzle head having a plurality of nozzle apertures of a maximum diameter of 4 mm each, and water-moistened guide member for cooling and guiding the plastic strands exiting the nozzle aperture via inlet rollers to the inlet of the cutting unit for chopping up the plastic strands into granules approx. 2-3 mm in length. The flow rate of the melt, with the strands being cooled down on their way from the nozzles via the guide member the feed rollers of the cutting unit, of at least 100 m/min in the central spatial region of the nozzle apertures will be increased to such an extent that the cutting unit will chop up the strands at a cutting rate of >2,000 cuts/s.

Abstract: A process for production of polyethylene terephthalate pellets includes the steps of: production of a melt of polyethylene terephthalate material; production of polyethylene terephthalate pellets from the melt by means of underwater pelletization into a process fluid; removal of the polyethylene terephthalate pellets from the site of underwater pelletization in the process fluid; crystallization of the polyethylene terephthalate pellets in the process fluid, wherein a surface of the polyethylene terephthalate pellets is crystallized and an interior of the polyethylene terephthalate pellets remains amorphous.

Abstract: One or more embodiments of a device for avoiding the uncontrolled discharge of melt from nozzle apertures of a nozzle plate are provided. The device can include a locking member that is movable in front of the nozzle plate. The locking member can be formed as an extrudate collection member. The locking member can be reciprocable between a production position and a collection position. And melt can be discharged from the nozzle apertures of the nozzle plate in the form of extrudates into a process chamber when the locking member is in the production position and into extrudate collection member when the locking member is in the collection position. The device can also include a melt extraction aperture disposed on the extrudate collection member. The melt extraction aperture can be configured to align with the nozzle apertures in the nozzle plate and a melt extraction channel.

Abstract: A process for production of polyethylene terephthalate pellets includes the steps of: production of a melt of polyethylene terephthalate material; production of polyethylene terephthalate pellets from the melt by means of underwater pelletization into a process fluid; removal of the polyethylene terephthalate pellets from the site of underwater pelletization in the process fluid; crystallization of the polyethylene terephthalate pellets in the process fluid, wherein a surface of the polyethylene terephthalate pellets is crystallized and an interior of the polyethylene terephthalate pellets remains amorphous.

Abstract: A drop pelletizing device and method for producing pellets from a low-viscosity plastic melt are provided. The drop pelletizing device can include a die plate with holes, in which the plastic melt can be subjected to a harmonic pressure oscillation such that the plastic melt emerging from the holes forms individual pellet droplets, a pressure vessel, in which prevails an overpressure above the ambient pressure, a discharge device adapted to discharge the individual pellet droplets from the pressure vessel and to reduce the overpressure, a separator adapted to separate the individual pellet droplets from the coolant; and at least one circulating device adapted to agitate the coolant to separated and unclump the individual pellet droplets in the coolant and for producing turbulence within the coolant.

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

Abstract: The invention relates to an apparatus for continuous casting and granulating strands of a thermoplastic material which uses a nozzle head having a plurality of nozzle apertures of a maximum diameter of 4 mm each, and water-moistened guide means for cooling and guiding the plastic strands exiting the nozzle aperture via inlet rollers to the inlet of the cutting unit for chopping up the plastic strands into granules approx. 2-3 mm in length. The flow rate of the melt, with the strands being cooled down on their way from the nozzles via the guide means to the feed rollers of the cutting unit, of at least 100 nm/min in the central spatial region of the nozzle apertures will be increased to such an extent that the cutting unit will chop up the strands at a cutting rate of >2,000 cuts/s.

Abstract: One or more embodiments of a device for avoiding the uncontrolled discharge of melt from nozzle apertures of a nozzle plate are provided. The device can include a locking member that is movable in front of the nozzle plate. The locking member can be formed as an extrudate collection member. The locking member can be reciprocable between a production position and a collection position. And melt can be discharged from the nozzle apertures of the nozzle plate in the form of extrudates into a process chamber when the locking member is in the production position and into extrudate collection member when the locking member is in the collection position. The device can also include a melt extraction aperture disposed on the extrudate collection member.