An extruder has a barrel extending from a feed inlet end to an extruder outlet end. The barrel has an inner surface, an outer surface, and a wall thickness between the inner and outer surfaces. The extruder also has at least one heating member positioned provided on the barrel; a screw drive motor drivingly connected to a rotatably mounted screw positioned within the barrel, whereby the screw is rotatable at various revolutions per minute (RPM); and a controller is operably connected to the screw drive motor to adjust the RPM of the screw based upon a temperature of material passing through and/or being extruded from the barrel. Methods for operating an extruder filling a mold are also provided.

The invention relates to a process for extruding plastic compositions, in particular polymer melts and mixtures of polymer melts, above all thermoplastics and elastomers, particularly preferably polycarbonate and polycarbonate blends, also with the incorporation of other substances such as for example solids, liquids, gases or other polymers or other polymer blends with improved optical characteristics, with the assistance of a multi-screw extruder with specific screw geometries.

In a method and an apparatus for increasing the intrinsic viscosity of a polycondensate melt at negative pressure, the melt enters a chamber, in which a negative pressure of less than 20 mbar prevails, through a perforated plate or a screen having openings with a diameter of less than 0.5 mm. The melt passes through this chamber in free fall in thin threads and remains in a reservoir beneath the chamber for at least one minute. The melt is moved constantly in the reservoir, and discharged from the reservoir, by a helical mixing and discharge part.

The present invention relates to a process for devolatilising polymer-containing media such as, in particular, polymer melts, polymer solutions and dispersions and also devolatilisation apparatuses for carrying out the abovementioned process.

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 (h.sub.1), 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

The present invention relates to a process for devolatilising polymer-containing media such as, in particular, polymer melts, polymer solutions and dispersions and also devolatilisation apparatuses for carrying out the abovementioned process.

The application relates to a plasticizing unit with a cylinder and a screw that is rotatably mounted in the cylinder and has a screw section which is designed as a shearing section and in which a blocking web encircling the screw core in a helical manner and a main screw thread enclosed by the blocking web are provided. A shearing web runs in the main screw thread parallel to the blocking web at a lower height than the blocking web. In this manner, two screw threads are produced which run parallel to each other and are separated by the shearing web. The threads are designed in the form of wave screw threads. Each wave screw thread is equipped with one or more wave peaks with a surface which is designed in the form of a plateau and forms a wave peak shearing surface, wherein the wave peak shearing surface is located at the same height as the surface of the shearing web in the region. The shearing web surface section which lies in the region of a wave peak shearing surface constitutes a shearing web sharing surface. A wave peak shearing surface and a shearing web shearing surface together form a total shearing surface. A specified total shearing surface together with the inner wall of the cylinder forms a shearing gap in accordance with a shearing gap size specified for the total shearing surface.

The application relates to a plasticizing unit with a cylinder and a screw that is rotatably mounted in the cylinder and has a screw section which is designed as a shearing section and in which a blocking web encircling the screw core in a helical manner and a main screw thread enclosed by the blocking web are provided. A shearing web runs in the main screw thread parallel to the blocking web at a lower height than the blocking web. In this manner, two screw threads are produced which run parallel to each other and are separated by the shearing web. The threads are designed in the form of wave screw threads. Each wave screw thread is equipped with one or more wave peaks with a surface which is designed in the form of a plateau and forms a wave peak shearing surface, wherein the wave peak shearing surface is located at the same height as the surface of the shearing web in the region. The shearing web surface section which lies in the region of a wave peak shearing surface constitutes a shearing web sharing surface. A wave peak shearing surface and a shearing web shearing surface together form a total shearing surface. A specified total shearing surface together with the inner wall of the cylinder forms a shearing gap in accordance with a shearing gap size specified for the total shearing surface.

A twin-screw extrusion device is disclosed, which includes a barrel and a twin-screw mechanism, the twin-screw mechanism includes a first screw, a second screw and a drive assembly, the drive assembly includes a plurality of idler gears and two mutually engaged elliptical gears, one of the elliptical gears is fixedly connected to the first screw, the other elliptical gear synchronously rotates with one of the idler gears, the last idler gear is fixedly connected to the second screw, a rotation speed of the first screw is .sub.1=N, an eccentricity of each of the elliptical gears is k, 0<k<0.8, an included angle between a connecting line of the first screw and the second screw and a long axis of each of the elliptical gears is , and a rotation speed of the second screw is .sub.2, satisfying

[00001]${}_2=\frac{\left(1-k^2\right)N}{1-2k\cos +k^2}.$

A twin-screw extrusion device is disclosed, which includes a barrel and a twin-screw mechanism, the twin-screw mechanism includes a first screw, a second screw and a drive assembly, the drive assembly includes a plurality of idler gears and two mutually engaged elliptical gears, one of the elliptical gears is fixedly connected to the first screw, the other elliptical gear synchronously rotates with one of the idler gears, the last idler gear is fixedly connected to the second screw, a rotation speed of the first screw is .sub.1=N, an eccentricity of each of the elliptical gears is k, 0<k<0.8, an included angle between a connecting line of the first screw and the second screw and a long axis of each of the elliptical gears is , and a rotation speed of the second screw is .sub.2, satisfying

[00001]${}_2=\frac{\left(1-k^2\right)N}{1-2k\cos +k^2}.$