摘要:
A process is provided for extruding a bimodal polyethylene resin. The process includes providing a polyethylene homopolymer or copolymer resin having a bimodal molecular weight distribution; conveying the resin through an extruder having a feed zone in which the resin is not melted, a melt-mixing zone in which at least a portion of the resin is melted, and a melt zone in which the resin is in a molten state, each zone being partially filled with the resin; and contacting the molten resin in the melt zone with a gas mixture of 8 to 40% by volume O2. The resin can be further pelletized. The oxygen-tailored resin can be used to make polyethylene films having improved bubble stability.
摘要:
An improved twin screw extruder device (14) is provided which is capable of producing a wide variety of high quality extrudates having greatly varying final properties, without the need for extensive machine modifications. The extruder (14) includes a barrel (16) together with a co-rotating twin screw assembly (22). The assembly (22) is made up of a pair of screws (50, 52) having central, tapered shafts (54, 56) equipped with outwardly extending helical flighting (58, 60); the screws (50, 52) are non-parallel and are positioned so that the flighting (58, 60) thereof is intercalated along the length of the screws (50, 52). The flighting is of specialized configuration and tapers along the length of the screws (50, 52) preferably at an angle of taper different than that of the shafts (54, 56); moreover, the width of the outer flighting surfaces (70, 72) increases along the length of the shafts (54, 56). This screw geometry defines a series of alternating upper and lower close-clearance high-pressure nip areas (78) defined by the flighting (58, 60) which serves to propel an extrudable mixture forwardly towards the outlet end (20) of the barrel (16). However, passageways (80) and kneading zones (82) are also defined between the screws (50, 52), which assures full mixing, shearing and cooking of the material. The extruder device (14) is capable of producing high density sinking aquatic feeds as well as expanded, low density products merely by changing the rotational speed of the screws (50, 52) together with appropriate temperature control. In another embodiment, a fluid extraction extruder (138) is provided having a specialized extruder head (140) including an outer shell (144) and an inner, elongated, slotted sleeve (152).
摘要:
A screw to be used in an extruder has a modular structure so that it can be adapted very flexibly to new tasks and conditions. The modular structure of a screw contains a rod-shaped mandrel and individual screw components which are slidable onto the mandrel. The components perform the classic functions of the screw during the extrusion process, such as conveying, kneading, mixing or shearing of the plastic to be guided into and through the plant.For transmission of the occurring high torque, the components are connected with the mandrel so that they positively engage and are axially braced in addition. The connection is to be performed such that it can be released by simple means.
摘要:
An Extruder for providing a flow of viscoelastic material such as rubber is disclosed herein. The extruder includes several zones (A, P, H, S), each assigned to a particular rheological function and arranged axially from an upstream end to a downstream end of the extruder and having an endless screw of given diameter (D). In each of the zones, at least one helicoidal flight extends radially from a central shaft of the screw over a height (h1), in a direction and with a pitch which are defined for each of the zones, and which is rotationally driven about an axis (XX′) in a barrel. The barrel is provided with various structures to further assist with the flow of the viscoelastic material
摘要:
The extruder includes: a cylinder having a first end portion and a second end portion respectively formed at two ends of the cylinder in an axial direction, and an ejection port formed in the first end portion; a screw including a shaft that is configured to rotate within the cylinder, and a screw blade that is provided on an outer circumferential surface of the shaft; a supplier that is attached to the second end portion side of the cylinder and is configured to supply a kneading target to an inside of the cylinder; and a plurality of protruding members that protrude from an inner wall surface of the cylinder.
摘要:
The present disclosure relates to devices for extruding plastics, notably mixtures of elastomers which are intended to be used in the manufacture of tires.
摘要:
A method is provided for manufacturing a liquid crystal polyester molded body by molding a liquid crystal polyester composition using a molding machine containing a cylinder, a screw and a heater. The screw is provided inside the cylinder, and is composed of a feed section, a compression section, and a metering section, the feed section and the compression section of the screw are composed of a single flight, the heater is provided on the outer periphery of the cylinder. The liquid crystal polyester composition contains a liquid crystal polyester and a polyamide resin. The method for manufacturing the polyester molded body includes: a step of melting and metering the liquid crystal polyester composition, a step of tightening a mold and performing mold clamping, a step of injecting the melted liquid crystal polyester composition into the mold, and a step of extracting the solidified resin from inside the mold.
摘要:
High-capacity extrusion die assemblies (20, 90, 130, 140, 180, 252) each having a tubular sections (44, 146, 162, 268) and an elongated, axially rotatable, helically flighted screw section (56, 56a, 152, 168, 276, 278) which cooperatively define frustoconical, outwardly diverging material flow paths (75, 160, 291) at constant or differing divergence angles of from about 1-11°. The use of diverging tubular sections (44, 146, 162, 268) and screw sections (56, 56a, 152, 168, 276, 278) permits the use of larger die plates (76, 118, 292) with an increased number of die openings (80, 124, 296). This allows significant increases in extrusion production rates. The die assemblies (20, 90, 130, 140, 180, 252) can be used in the production of a wide number of human foods or animal feeds, and particularly aquatic feeds of the floating or sinking variety. In another aspect of the invention, an extruder (210) is provided having diverging and converging sections (212, 214) along the length thereof and defining corresponding flow paths (230, 246).
摘要:
A process for producing a solid dispersion of an active ingredient which comprises feeding the active ingredient and a matrix-forming agent to an extruder and forming a uniform extrudate, wherein the extruder comprises at least two rotating shafts (2), each of the shafts (2) carrying a plurality of processing elements disposed axially one behind the other, the processing elements defining (i) a feeding and conveying section (A), (ii) at least one mixing section (B), and (iii) a discharging section (E), wherein the processing element(s) defining the mixing section (B) comprise(s) a mixing element (11, 12, 13) that is derived from a screw type element (FIG. 2).
摘要:
A method of manufacturing a thermoplastic resin film, comprising the steps of: discharging a molten thermoplastic resin in film form from a die; and conveying the discharged film by a plurality of multi-staged cooling rollers with the discharged film contacting the rollers to cool the discharged film at multiple stages, wherein the temperature of surface of a first cooling roller out of the plurality of cooling rollers provided at multiple stages, the first cooling roller being positioned at the most upstream side in the direction in which the film is conveyed, ranges from the glass-transition temperature (Tg) of the thermoplastic resin−40° C. or higher to Tg+30° C. or lower.