A plant for drying and solid state polycondensing a granular moisture-containing polymeric material includes a conduit feeding material to be treated longitudinally, a treatment zone located along the conduit, a blower of an inert gas into the conduit, and a radiating device emitting an alternating electromagnetic field in the radio-frequency band to dry and upgrade the material. The radiating device includes applicators, located at the treatment zone and external to the conduit in longitudinally offset positions, which are connected to the terminals of an electromagnetic wave generator and include pairs of opposed radiating elements that generate an alternating electromagnetic field in the conduit, with field lines at least partially parallel to the direction of feed of the material, and that define magnetic dipoles with opposite polarities along the conduit. A method of drying and solid state polycondensing a polymeric material in granular form obtained by polycondensation using the plant.

The present invention discloses a method for preparing a PET/PTT parallel complex filament with high self-crimpiness, wherein PET and PTT are sliced, dried and crystallized, and then fused separately and subjected to extrusion molding through a parallel-type spinneret plate; oil is applied after cooling; then level 1-3 drafting and heat setting treatment are adopted; and during drafting, a total drafting rate is controlled to be 3 to 3.5, wherein the level-1 drafting rate is 2.8 to 3.0 at a temperature controlled to be 75 to 80? C., according to the method for preparing the PET/PTT parallel complex filament with high self-crimpiness, methods like multi-level drafting for increasing the drafting rate are adopted, and the effects of improving the fiber strength, moderately lowering the breaking elongation, and greatly improving the self-crimpiness are achieved.

The present subject matter claims a process and apparatus for forming, crystallizing and increasing the molecular weight of polymer particles which does not require re-heating the polyethylene terephthalate (PET) pellets after they are cut and crystallized in the under water cutting (UWC) section. In the existing solid state polycondensation (SSP) technologies where an

UWC is used, high crystallinity of the PET pellets can occur, by cooling and re-heating the PET pellets, which results in reduced removal efficiency of by-products, such as acetaldehyde (AA) and furthermore also a reduction of the reaction rates of molecular weight increasing reactions.

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. After separation from the process fluid in the first separating device, the plastic granulate is fed continuously in a line to a dealdehydization container (46).

The invention relates to a method for processing PET polymers in order to form PET pellets. A PET melt is granulated in an underwater granulator in order to form PET pellets, wherein the process water is driven at a temperature below the glass transition temperature of the used PETs in order to produce a golf ball-like surface structure on the pellets during the underwater granulation process. According to the invention, the pellets are separated from the super-cooled process water within a second or less and are subjected to an at least two-stage post-treatment process after the drying process, wherein the pellets are supplied with a gas of a first temperature which is higher than the surface temperature of the pellets for a first period of time, said gas being kept uniformly hot, in a first post-treatment chamber to form nuclei, and the pellets are treated in a second post-treatment chamber to crystallize at a second temperature which is higher than the first temperature over a second period of time which is a multiple of the first period of time.

A method for the production of granulate suitable for the production of extrusion-blow-molded hollow bodies, comprising: sorting by type, washing, and comminuting PET articles originating from a post-consumer collection of plastic packaging, removing contaminants from the PET articles, premixing PET material from various types of the sorted PET articles so that a Trouton ratio of mixed PET material at a shear rate of 50 to 200 s.sup.?1 is less than 4, drying the PET material, melting the dried PET material, pressing the PET material through a filter, dividing the PET material into individual melt streams, cooling and solidifying the melt streams in a water bath and separating the solidified melt flows into pellets, wherein the pellets have an intrinsic viscosity of 0.5 to 0.75 dl/g, crystallizing the pellets, and drying and condensing the crystallized pellets in a solid-phase polycondensation reactor until they reach an intrinsic viscosity of 1.0 to 1.7 dl/g.

A recycling method of waste fishnet is provided. The waste fishnet is processed with steps of cutting, removing impurities, cleaning, and drying to form fishnet chips. The recycling method of waste fishnet includes the following steps. The fishnet chips are mixed with nylon-66, wherein the fishnet chips are of 70% by weight, and nylon-66 is of 30% by weight. The mixture is heated and molten. The molten mixture is then processed with the step of granulation. The grains are then processed with the step of spinning Thereby, the waste fishnet can be recycled and transferred into useful plastic materials.

A method may facilitate the crystallization of granules of a crystallizable thermoplastic material in conjunction with removal of low molecular mass components contained in the thermoplastic material. The crystallizable thermoplastic material may have a crystalline melting temperature of at least 130 C. According to the method, a crystallization stage and a removal stage may be performed at different temperatures of the granules. Often the crystallization may occur at a lower temperature than the removal of the low molecular mass components. In the crystallization and removal stages, a flow of gas may pass countercurrent to a direction along which the granules are conveyed. Further, example devices disclosed herein may be utilized to perform the exemplary methods disclosed herein.

An apparatus for continuous pelletization and crystallization of a polymer includes a unit for forming a polymer pellet material and cooling the pellet material in a liquid cooling medium. An after-connected drying unit has an exit opening for exporting gas and a crystallizer for crystallizing the pellet material. The crystallizer communicates via a connection line with the pre-connected unit for separating the liquid cooling medium from the pellet material and drying the pellet material. The crystallizer communicates with an inert gas tank, whereby the pressure in the crystallizer can be increased relative to the pressure in the drying unit. A related process is also disclosed.

A heavy load vortex internal apparatus is provided having a vibration channel for receiving plastic granular material. The vibration channel has a channel floor and two side walls opposite each other, where the length of the vibration channel is greater in the longitudinal direction than the maximum height and width of a channel cross section perpendicular to the longitudinal direction. At least two vibration generators are provided for generating a vibration excitation having a transverse component perpendicular to a vertical plane in the longitudinal direction. At least two channel carriers are spaced apart from each other in the longitudinal direction, each supporting the channel floor and the side walls from the outside and bridging the vibration channel opposite the channel floor. One of the vibration generators in each case is fastened to at least two of the channel carriers. Also provided is a method for crystallization of plastic granular material.