Abstract: A screw rotates in a containment barrel, and comprises a shaft having an upstream end and a downstream end At least one flight is secured to the surface of the shaft and extends helically in successive turns around the circumference of the shaft. An upstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The upstream barrier is disposed proximal the upstream end of the shaft. A downstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The downstream barrier is disposed proximal the downstream end of the shaft.

Abstract: A screw element includes an outer radius Ra and a core radius Ri for multiscrew extruders with co-rotating and intermeshing screw shafts. The screw element has in axial cross section through its longitudinal axis a profile which has at each of the two axial end faces (i.e. a front end face and a rear end face) only one screw flight corresponding to a conventional single-start screw element for intermeshing screw shafts. In this case, the width (flight land angle ?) of the screw flight and conversely, in a corresponding way, the width (flight land angle ?) of the screw flight are formed in a special way and a shearing flight with a constant shearing flight radius Rs, which is greater than Ri, and less than Ra, is provided.

Abstract: An extruder mixer and method for mixing plastic materials utilizes an elongated screw having an inlet channel connected to a first cross-axial pump that feeds, at an angle to the screw axis, a subsequent channel, wherein the subsequent channel becomes a further inlet channel connected to at least one subsequent cross-axial pump, and wherein the cross-axial pump is bounded by a flight on at least one side.

Abstract: An object of the invention is to provide an injection molding process for preparing thermoplastic resin molded articles and an injection molding apparatus for use in practicing this process, the process and the apparatus being adapted to supply a blowing agent, especially a nonreactive gas such as carbon dioxide or nitrogen gas, to a thermoplastic resin continuously at a relatively low pressure with good stability to incorporate the agent or gas into the resin. As shown in FIG. 3, a resin in a cylinder (2) of an injection molding machine (1) as melted by rotating a screw (3) is mixed and dissolves carbon dioxide which is supplied to the molten resin from a gas supply opening (5) formed in the screw (3). An amount of the gas-incorporating molten resin is measured out and injected into a mold cavity to obtain an expansion-molded article.

Abstract: High levels of treated fumed silica, processing fluid and high molecular weight silicone polymer are continuously compounded into a homogeneous silica filled heat-vulcanizable silicone composition by forming a premix in a continuous annular layer mixer and continuously discharging the premix into a compounding apparatus for compounding to form the filled heat-vulcanizable silicone composition.

Abstract: The invention relates to an extruder for the preparation of rubber mixtures for elastomeric products and comprises a cylinder, an endless screw rotatably mounted in the cylinder for uptake transport and homogenization of the rubber mixture, and an extrusion tool; wherein the endless screw is configured with zones of multiple treads in dependence of varying helix angle and depth of thread so that the rubber mixture transported through the zones undergoes a temperature increase through heat dissipation to such an extent that the temperature of the extrudate approaches the vulcanization temperature thereof.

Abstract: Each mixing rotor for a batch mixer is rotatably insertable into a mixing chamber such that tip clearances are defined between tips of mixing blades and an inner surface of a mixing chamber and is provided on its outer circumferential surface with a plurality of mixing blades for imparting shearing forces to a material to be mixed by causing the material to pass through the tip clearances. The plurality of mixing blades include a nonlinear blade which is substantially nonlinear from a start point to a terminal point in a development of the mixing rotor developed into a plane about its longitudinal axis, and other linear blades which are linear in the development and whose helix angle to the longitudinal axis of the mixing rotor is set at 15 to 35°. An appropriate mixing control capable of realizing both sufficient mixing and sufficient dispersion can be executed by mixing and dispersing the material in a well-balanced manner by means of the mixing rotor.

Abstract: An apparatus for conveying and melting plastic materials has a containment barrel that supplies heat for melting the plastic. A shaft rotates within the barrel and has a diameter, a circumference, and a surface. At least one flight is secured to the shaft and extends helically around its circumference. The flight, shaft and barrel cooperate to define a channel between successive turns of the flight, the channel having a depth and a width that define a channel area. The flighted shaft has an entry section at an upstream end of the flighted shaft, a transition section, and a discharge section at a downstream end of the shaft, the channel area in the transition section is larger than in the entry section. The difference in area between the entry and transition sections provides the advantage that avoids surging conditions and improves mixing.

Abstract: An extrusion molding apparatus capable of improving the extrusion rate of the ceramic material without a major reconstruction of a drive system is disclosed. The extrusion molding apparatus comprises screw extruders (2, 3) including housings (29, 39) having screws (4, 5) built therein, wherein the ceramic material introduced into the housings (29, 39), respectively, is extruded by way of the forward end extrusion ports by rotating the screws (4, 5). The screws (4, 5) built in the screw extruders (2, 3), respectively, include pressure portions (41, 51) with the feed rate per revolution progressively decreased toward the forward end extrusion port, and extended portions (43, 53) with the feed rate per revolution progressively increased toward the forward end extrusion port.

Abstract: A rotatable screw for moving material in a plasticating process along an axis through a conduit from an inlet to an outlet. The screw having a feed section, barrier melting section, reorientation section and metering section disposed sequentially downstream. The screw includes an axial core, and a helical main flight that extends radially from the core and is formed with recesses located at the first periphery and extending through the thickness of the main flight and radially toward the core. A helical secondary flight extends radially from the core between successive helical passes of the main flight, and is formed with recesses extending through the secondary flight and toward the core. Materials conveyed along the metering section can cross through the main flight at the recesses and recirculate, in addition to passing over the periphery of the secondary flight, for still further enhanced and homogenous mixing, before reaching the outlet.

Abstract: A new plasticity apparatus including a rotating and reciprocating screw having a hellcal flight that is wrapped around a core, disposed within and cooperting with the inner wall of a heated barrel that substantially increases the melt quality of a polymeric material. This is accomplished by incorporating an increase in the hefix angle of the primary flight at the taper terminus of the transition section, in cooperation with a stepped change in the root that terminates either upstream or downstream of the end of one complete revolution of the flight.

Abstract: The invention relates to a screw element with an outer radius Ra and a core radius Ri for multiscrew extruders with co-rotating and intermeshing screw shafts, in particular for twin-screw extruders, which has in axial cross section through its longitudinal axis (10) a profile which has at each of the two axial end faces (front end face 8, rear end face 8′) only a screw flight (1, 1′) corresponding to a conventional single-start screw element for intermeshing screw shafts. In this case, the width (flight land angle &phgr;) of the screw flight (1) and conversely, in a corresponding way, the width (flight land angle &phgr;) of the screw flight (1′) are formed in a special way and a shearing flight (7) with a constant shearing flight radius Rs, which is greater than Ri and less than Ra, is provided.

Abstract: A method and apparatus for converting liquid alloy into its thixotropic state and for fabricating high integrity components by injecting subsequently the thixotropic alloy into a die cavity. The apparatus includes a liquid metal feeder, a high shear twin-screw extruder, a shot assembly and a central control system. The apparatus and method can offer net-shaped components characterized by close to zero porosity, fine and equiaxed particles with a uniform distribution in the eutectic matrix, and a large range of solid volume fractions.

Abstract: The invention relates to a single screw extruder comprising a barrier screw and a barrel in which the barrier screw is held in a manner that permits to rotate and comprising at least one feed zone longitudinal section and at least one melting zone longitudinal section (23). The extruder (10) is characterized in that the barrel (11), on the inner wall (50) thereof in the area of the melting zone longitudinal section (23), has at least one groove (52) which runs in a longitudinal direction. The invention also relates to a method for extruding plastic material using a single screw extruder (10) comprising a barrier screw (40) which is held inside a cylinder (11) in a manner that permits it to rotate, whereby the extruder (10) comprises a feed zone (21, 22) and a melting zone (23), and the barrier screw (40) has at least one solid matter channel (49) and a melting channel (48).

Abstract: The invention relates to a single screw extruder comprising a barrier screw and a barrel in which the barrier screw is held in a manner that permits to rotate and comprising at least one feed zone longitudinal section and at least one melting zone longitudinal section (23). The extruder (10) is characterized in that the barrel (11), on the inner wall (50) thereof in the area of the melting zone longitudinal section (23), has at least one groove (52) which runs in a longitudinal direction. The invention also relates to a method for extruding plastic material using a single screw extruder (10) comprising a barrier screw (40) which is held inside a cylinder (11) in a manner that permits it to rotate, whereby the extruder (10) comprises a feed zone (21, 22) and a melting zone (23), and the barrier screw (40) has at least one solid matter channel (49) and a melting channel (48).

Abstract: A plasticating screw having a feed section, barrier melting section, reorientation section and metering section disposed sequentially downstream wherein solid material is moved from a trail side of a main flight to a push side of the main flight in the reorientation section. The reorientation of solids is accomplished by discontinuing a barrier flight at a terminal end of said barrier melting section. The main flight decreases its pitch and continues into the reorientation section, which has a longitudinal length at least 360° about the screw axis. A melt channel and solids channel in said barrier melting section merge into a substantially uniform reorientation channel in the reorientation section so that solid plastic material conveyed along the reorientation section moves toward the push side of the main flight.

Abstract: The invention provides a molding apparatus adapted to use a screw having an overall length permitting the use of an existing molding machine cylinder as it is, and is capable of realizing a gas impregnation step. The screw 3 for use in the gas impregnation step comprises a resin melting portion C disposed at an upstream position for rendering the resin molten, a molten resin nonfilled-up portion E integral with the downstream side of the resin melting portion C for making the resin lower than an inert gas at a gas supply opening 5 in pressure, and a gas impregnation portion D integral with the downstream side of the molten resin nonfilled-up portion E for supplying the inert gas and impregnating the molten resin with the inert gas.

Abstract: An extruder screw includes an energy transfer section divided into successive barrier sections in which a channel formed by a first thread is divided into at least two sub-channels by a second thread. A ratio of the difference in outer diameters of the threads is approximately inversely proportional to the ratio of the lengths of adjacent ones of the barrier sections.

Abstract: An extruder screw for processing plastic material, in particular for a plasticizing barrel of an injection molding machine, has at least one screw flight divided along its length into successive zones including a mixing and transformation zone for plasticizing plastic material and a subsequent discharge zone for expelling plastic material. The screw flight is formed in the mixing and transformation zone with at least one breach to define a through passage for return of a partial mass flow to a neighboring screw turn, whereby the screw flight extends towards a discharge end of the discharge zone of the extruder screw along a helical line having same thread direction and being offset in axial direction in the area of the breach.

Abstract: A method for processing an impact modifier material having a core and shell molecular structure comprises working the impact modifier material in a mild extruder to a state such that at least a portion of the shells of the impact modifier material fuse together to form an impact modifier material output, and pelletizing the impact modifier output. The output is preferably pellitized, and produces pellets having a narrow size distribution.

Abstract: A polymer is fed upstream into an extruder. The polymer is melted and mixed in a zone (A). Cellulosic fibres are fed into the extruder in a zone (B). A mixture of the polymer and the fibres obtained in zone (B) is transported through a degassing zone (C) and then through a pressure building zone (D). The mixture is released from zone (D) into a die. Each of zones (A), (C) and (D) includes at least one positive transportation screw element. The zone (B) includes at least one positive transportation screw element, at least one kneading section and at least one negative transportation screw element such that the cellulosic fibres are fibrillated to obtain cellulosic fibres with an aspect ratio as high as possible while simultaneously mixing the cellulosic fibres with the melted polymer.

Abstract: A mixing section for a feed screw includes a body portion defined along a longitudinal axis. The mixing section further includes a primary flight defining a helical channel, wherein the primary flight is helically wound in a first direction about the longitudinal axis. The primary flight forms a first acute angle with respect to a first plane including the longitudinal axis and defines a cross channel to allow fluid communication between adjacent portions of the helical channel. The cross channel is defined along a second plane such that the second plane forms a second acute angle with respect to the first plane. The first and second acute angles are located in the same quadrant and the second angle is less than the first angle.

Abstract: A method and system are provided that efficiently compound high levels of inorganic filler, processing fluid and silicone polymer at a commercial rate into homogeneous filled and devolatilized silicone compositions. In the method, filled silicone compositions are compounded by compounding a filler, processing fluid and silicone polymer in a first compounding apparatus to produce a first dispersed composition and simultaneously compounding a filler, processing fluid and silicone polymer in a second compounding apparatus that shares a common extruder shaft with the first compounding apparatus to produce a second dispersed composition. The system comprises a first compounding apparatus and a sequential second compounding apparatus that shares a common shaft with the first compounding apparatus.

Abstract: A screw comprising a screw shaft having a thread spirally positioned about the screw shaft so as to form a plurality of flights, said screw having a feeding zone, a compression zone and a metering zone, and means in said screw for providing a mass of material in a flight in the feeding zone that is substantially the same as the mass of material in a flight in the metering zone, wherein said means includes flights formed in the metering zone having a pitch and depth based upon the volume of the material in a molten state and flights formed in the feeding zone having a pitch and depth based upon the volume of the material in a bulk state. This design results in a screw which has a balanced mass flow, and thus a constant pressure gain along the screw without pressure peaks.

Abstract: A cylindrical apparatus or module to be included in a screw of a plasticating device. The screw has a helical flight disposed within and cooperating with the inner-wall of a heated barrel to form an upstream where material is fed into and a downstream where material exits the device. The cylindrical module has a helical channel traversing in a reverse helical direction compared with the direction of the flight. Input grooves extend in the surface of the module with input groove openings beginning within the helical channel and terminating in a dead end before intersecting the channel upstream. Output grooves, being adjacent to the input grooves, extend in the surface of the module with output groove openings beginning within the helical channel and terminating in a dead end before intersecting the channel downstream. A barrier is between the pair of adjacent input and output grooves to prevent direct communication therebetween.

Abstract: A plasticating screw having a main channel defined by a helical flight disposed within and cooperating with an inner-wall of a heated barrel. The screw has a longitudinal portion with a plurality of staggered rows of noncontinuous advancing grooves arranged in the main channel thereof. The axis of each row of advancing grooves being substantially parallel to the helical axis of the adjacent helical flight of the longitudinal portion. A noncontinuous helical channel is formed therein traversing in a reverse direction, compared with the direction of the helical flight, the channel having a plurality of retracting grooves. Each retracting groove cuts through at least one pass of the main channel of the longitudinal portion, including the advancing grooves therein, and intersects and passes through the helical flight at least once, so that molten resin can back flow and re-circulate therethrough.

Abstract: An extruder screw includes an energy transfer section divided into successive barrier sections in which a channel formed by a first thread is divided into at least two sub-channels by a second thread. A ratio of the difference in outer diameters of the threads is approximately inversely proportional to the ratio of the lengths of adjacent ones of the barrier sections.

Abstract: An extruder screw mechanism has a barrel that is heated by heating coils, an internal screw, and a cylindrical melt sleeve having a plurality of circumferentially spaced, axially extending, radial slots there through located between the external barrel and the internal screw. Another embodiment of the extruder has a barrel and an internal screw, with the internal screw having either a single central axial bore or a plurality of internal axial bores. The internal screw is provided with a plurality of external threads, with the threads each having a curved starting portion with a helix angle that has a finite value and gradually increases along an initial portion of the screw until the threads are substantially linear and parallel to the axis of the screw along the melting portion of the screw; a related embodiment has threadless portion separating the linear threads from the curved upstream threads.

Abstract: The invention relates to a single screw extruder comprising a barrier screw and a barrel in which the barrier screw is held in a manner that permits to rotate and comprising at least one feed zone longitudinal section and at least one melting zone longitudinal section (23). The extruder (10) is characterized in that the barrel (11), on the inner wall (50) thereof in the area of the melting zone longitudinal section (23), has at least one groove (52) which runs in a longitudinal direction. The invention also relates to a method for extruding plastic material using a single screw extruder (10) comprising a barrier screw (40) which is held inside a cylinder (11) in a manner that permits it to rotate, whereby the extruder (10) comprises a feed zone (21, 22) and a melting zone (23), and the barrier screw (40) has at least one solid matter channel (49) and a melting channel (48).

Abstract: An apparatus and a method for controlling a degree of attrition or wear of a sealing screw conveying plasticized material are provided. The apparatus includes an opening which intersects the wall of a housing of the screw in the region of the screw threads or in the region immediately neighboring the screw threads. Another opening intersects the wall of the housing. The two openings are spaced apart axially from each other and the pressure sensors connected to both openings. The process involved conveys a plasticized material against a resistance, the resistance being a sealing screw bearing supported within the screw housing. The pressure of the conveyed material is measured at two locations spaced apart from each other in the direction of conveyance. The two locations are disposed on both sides of a resistance body towards which the sealing screw conveys the material. The difference between the two measured values is used to indicate the degree of wear of the screw or its housing, respectively.

Abstract: An internal batch mixing machine includes a mixing chamber having a pair of cavities in which a first and a second rotor are mounted adjacent one another and are driven in opposite directions to mix material. The circumference of each rotor is divided into first, second, third and fourth sequential quadrants spaced in a direction opposite to the intended direction of rotation of that rotor. Each of the rotors has preferably a pair of lobes or wings located in every other quadrant of that rotor, although three lobe rotors are possible. Each lobe has a leading end and a trailing end. The first rotor has a pair of lobes located in its first and third quadrants, while the second rotor has a pair of lobes located in its second and fourth quadrants. One of the lobes of each pair of lobes is longer than the other, and each lobe extends downstream at an acute cohelix angle toward the other lobe of its pair.

Abstract: A compact extruder with multiple parallel screws having a variable pitch arrangement, includes an outer casing which has at least two chambers that contain at least two screws which allow material to flow from one chamber to the other chamber through a passage, and that present a feed inlet for the material to be treated and an outlet for the material; each chamber has at least one pair of housings for the corresponding pair of screws which engage with one another, each screw presenting a long-pitch portion and a short-pitch portion.

Abstract: The manufacture of a plastic material, particularly provided with fibers, is frequently carried out in an extruder (10). Various problems have arisen in this connection. For example, problems arise in working long or endless reinforcement fibers, for example rovings (27), into the plastic. On the one hand, the fibers are so badly broken up that they have only very small lengths. On the other hand, it has proved difficult to impregnate the fibers sufficiently. According to the invention, in order to feed in fibers, the plastic is moved in batches past a pre-plastifying worm (11). This is achieved by a secondary worm (18) located next to the pre-plastifying worm (11).

Abstract: A spiral conveyor for a concrete extrusion machine has a first spiral conveyor section with a first external diameter. There is a second spiral conveyor section having a second external diameter which is greater than the first diameter. The second section is spaced apart from the second section. A third spiral conveyor section is between the first section and the second section. The first end of the third section is connected to the first section and the second end is adjacent to the second section. The second spiral conveyor section may be mounted on a hollow shaft of the third section. The second section has two longitudinally divided components, each having a recess therein. Connectors interconnect the two components and a locking device is between the hollow shaft and the second section.

Abstract: Rotor (5) for machines (1) mixing elastomers and the like, comprising a first section of greater axial length (L1), defining a thrusting flange (6), and a second section of smaller axial length (L2), defining a counter-thrusting flange (7), in which at least one of said thrusting flange (6) or counter-thrusting flange (7) has an angle of entry (&bgr;,&sgr;) into the mixture, which is varied along its extension.

Abstract: The invention relates to a process for controlling the degree of attrition or wear of a sealing screw (8) conveying a plasticized material, in particular synthetic plastic material, against an resistance, wherein the sealing screw (8) is bearingly supported within a screw housing (4). For this, the pressure of the conveyed material is measured at two locations spaced apart from each other, when seen in direction of conveyance. These two locations are disposed on both sides of a resistance body (12) towards which the sealing screw (8) conveys. The difference of the two measured values is used for indicating the degree of wear of the screw (5) or its housing, respectively.

Abstract: A barrel contains an extruder conveying screw which has a drive end, a feed section, a melting section and a pumping section wherein the screw has a vent hole located from 0 to 2 screw diameters from the beginning of the feed section. An axial bore in the screw vents gases from the barrel through the gas vent hole and into the axial bore.

Abstract: When a desired preform is to be molded from a molding material which is a polyester resin composed of a blend of PET and PEN by compressing and melting the molding material by the rotation of a screw in a heating cylinder and injecting and filling the molten material into a mold, a plastication zone 13 for the molding material is formed between a compression zone 12 of the injection screw 2 and a metering zone 14 at an end of the screw. In the plastication zone 13, the molding material is subjected to melting, relaxation, kneading and relaxation steps in order to melt and remove an unmolten material until the molten material reaches the metering zone 14. To prevent a molded article from becoming opaque and the production of a gel-like unmolten granular material when a polyester resin composed of a blend of PET and PEN is used as a molding material.

Abstract: A plasticating apparatus adapted to handle a wide variety of synthetic resinous materials without predrying. The plasticating apparatus includes a two-stage screw rotatably and reciprocably mounted within a barrel. A surge suppressor is provided between the first and second stages and is comprised of an integral protrusion of the screw root and a deep channel section immediately preceding the protrusion. The surge suppressor prevents the surge of molten material into the vent area following the holding portion of an injection molding cycle, thereby allowing faster recovery and preventing bleeding of plasticized material from the vent opening.

Abstract: A screw adapted for plasticizing a fiber-reinforced thermoplastic resin wherein screw lead (distance of the resin advancement in the direction of the axis per 1 revolution of the screw when it is postulated that the screw channel is 100% filled with the resin) of the screw in its compression section decreases in the direction toward the forward end of the screw. A plasticizing apparatus wherein such screw is mounted. A method for molding a fiber-reinforced thermoplastic resin by using such an apparatus. A molded article produced by such molding method. In the present invention, shear force of sufficient level can be obtained to avoid the formation of clumps while breakage of the reinforcing fibers is avoided to leave long fibers in the molded article. The resulting molded article has excellent mechanical properties, and such article is quite useful as a material for use in automobile parts and other parts.

Abstract: A plasticating screw having improved mixing capability for polymer blends comprises a feed zone having a helical flight defining a solid material feed path, a compression zone for converting the solid material into molten material having a helical channel of variable depth, a waved melting zone for breaking up solid agglomerations and distributing them equally in the liquid melt, a spiral mixing zone that traps large agglomerations and contaminants, and a second melting zone for completing melting the material and for creating a substantially homogeneous melt. A method for mixing plastic material that has been at least partially plasticized and contains inhomogeneities is also described.

Abstract: A method of and device for removing a liquid from a resin of high melting point by means of a co-rotating twin extruder and an operation system of a liquid removal molding of a resin of high melting point by which a scaled down, highly effective, high performance and continuous stable operation of the device may be achieved.

Abstract: In a twin extruder wherein an underwater cutting apparatus 12 is connected, via a gear pump 9, to an discharge port 8 of a cylinder 1 which houses therein twin screws both ends of which are supported, both sides of both screws 2, 3 are material conveying sections 5a, 5b having flights of small lead, the downstream sides of the respective material conveying sections 5a, 5b are kneading sections 6a, 6b having flights of large lead, both kneading sections 6a, 6b are connected about the center of the screws 2, 3, and the cylinder 1 positioned at the center of the screws 2, 3 is provided with the discharge port 8.

Abstract: An axially elongated extruder screw includes a screw body having an axially extending extruding portion defined by a feed section at an inlet end of the screw, a metering section at an outlet end of the screw and a barrier section between the feed and metering sections. At least one helical primary flight extends about and is coaxial with the screw body. The primary flight and the screw body cooperate to form a channel in the feed section for conveying resinous material to the barrier section. The barrier section includes at least one helical secondary flight extending from the primary flight about the screw body which in turn defines a first surface of revolution between the primary and secondary flights. At least one helical tertiary flight is positioned between the primary and secondary flights and also extends about the screw body which defines a second helical surface of revolution between the secondary and tertiary flights.

Abstract: An axially elongated extruder screw includes a screw body having an axially extending extruding portion defined by a feed section at an inlet end of the screw, a metering section at an outlet end of the screw and a barrier section between the feed and metering sections. At least one helical primary flight extends about and is coaxial with the screw body. The primary flight and the screw body cooperate to form a channel in the feed section for conveying resinous material to the barrier section. The barrier section includes at least one helical secondary flight extending from the primary flight about the screw body which in turn defines a first surface of revolution between the primary and secondary flights. At least one helical tertiary flight is positioned between the primary and secondary flights and also extends about the screw body which defines a second helical surface of revolution between the secondary and tertiary flights.

Abstract: A barrel contains an extruder conveying screw which has a drive end, a feed section, a melting section and a pumping section wherein the screw has a vent hole located from 0 to 2 screw diameters from the beginning of the feed section. An axial bore in the screw vents gases from the barrel through the gas vent hole and into the axial bore.

Abstract: A process for preparing thermoplastics or polymer blends comprising (A) from 5 to 95% of a water-moist elastomer component containing up to 60% of residual water, (B) from 5 to 95% of a thermoplastic polymer, (C) from 0 to 95% of a further polymer, and (D) from 0 to 70% of additives, said process comprising mixing the components A to D in an extruder with mechanical dewatering of component A, wherein the extruder has at least two rotating screws and, in the conveying direction, is essentially composed of a metering section into which component A is fed, a squeeze section which serves for dewatering component A and contains a retarding element and an associated dewatering orifice which is present upstream of the retarding element by a distance corresponding to at least one screw diameter, a feed section in which the thermoplastic polymer B is introduced as a melt into the extruder, a plastication section with mixing or kneading elements, a devolatilization section with an orifice and in which the remaining wat

Abstract: An axially elongated extruder screw includes a screw body having an axially extending extruding portion defined by a feed section at an inlet end of the screw, a metering section at an outlet end of the screw and a barrier section between the feed and metering sections. A first helical primary flight extends continuously about and is coaxial with the screw body substantially along the entire length of the extruder screw. A second helical primary flight extends continuously at least part-way along the feed section to the outlet end of the extruder screw. The barrier section of the extruder screw defines first and second barrier flights positioned between the primary flights and cooperating therewith to form first and second melt and solids channels that extend along the barrier section of the extruder screw.

Abstract: The invention relates to a multiscrew, continuous mixing machine for plasticizable compounds with two screws, which rotate in the same direction in a housing and which penetrate the cylindrical part of the housing that envelopes the screws. The screws include axially spaced apart conveying sections and at least one mixing section therebetween. The conveying sections are formed by intermeshing conveying screws. The mixing section is formed by mixing elements. The mixing elements are followed by restricting elements which include short screw elements with back feed thread. The back feed thread forms a vertex, which progresses radially shortened along a thread in such a way that the radius of the vertex is shorter on the inlet side than on the outlet side and inbetween increases continuously towards the outlet side.

Abstract: A cast polymer integral mixing and vacuum processor system and method for delivering substantially void-free viscous polymer employs a motor connected to a mixing screw. A tube surrounds the mixing screw with one end of the tube being fixedly connected relative to the motor. The mixing screw has a thread thereon having varying pitch zones. In a loading thread pitch zone a relatively wide thread pitch is provided for receiving dry material filler at a filler input and resin at a resin input. At a first mixing and sealing thread pitch zone, a relatively narrow thread pitch is provided so as to form a vacuum seal and provide mixing of the resin with the filler material. At a void removal thread pitch zone a substantially wide thread pitch is provided and at which a vacuum tower is located in which a vacuum is maintained to remove voids formed by gas in mixed material.