A system and method for reducing draw resonance of plastic material in the molten state, so-called melt, leaving an extrusion group of a plant for the production of plastic film, includes at least one thermostatically-controlled cylinder, having an embracement angle, of the melt on the cylinder, adjustable on the basis of the process rate, i.e. the linear movement speed of the plastic film, and/or on the basis of the temperature measured in the proximity of or in correspondence with the clamping area of the melt in a thermoforming, calibration and cooling group included in the plant and positioned downstream of the system.

An extruder, such as a double-screw extruder includes a double cylinder and a double-lead screw arranged therein with a drive train for the screw. The drive train has a coupling with the screw. The extruder includes a sensor for recording a moment load having torque and/or bending moment and for generating electronic data from the recorded moment load. A controller is provided in operative connection to a drive for the drive train and the sensor is in data connection with the controller. The controller is adapted to evaluate the data on the recorded moment load and to trigger a protective action if a threshold value set in the controller is exceeded. The evaluation includes a bending moment calculation. A plastic molding plant produces a film with the extruder along with a nozzle unit and a cooling and wind-up unit or a compounding plant. A method for operating such a plant for manufacturing a film includes the extruder.

The production of a biaxially oriented tube from thermoplastic material, wherein a tube in preform condition is extruded from thermoplastic material using an extruder having an extruder die head with an inner die member that forms a lumen in the tube in preform condition. The tube in preform condition is subjected to a temperature conditioning. Use is made of a expansion device comprising a non-deformable expansion part having a gradually increasing diameter to a maximum diameter, which expansion part is contacted by the tube and exerts an expanding force so as to bring about expansion of the tempered tube in circumferential direction. The method comprises drawing the tempered tube over the expansion device using a drawing device, in such a manner that said tube is transformed from a tube in preform condition into a biaxially oriented tube with thermoplastic material which is oriented in axial direction and in circumferential direction of the tube.

A pressure chamber is provided for a blown film extrusion apparatus having (i) a die head for extruding a tubular polymer bubble, and (ii) a cooling assembly down-stream of the die head for receiving the bubble and applying a cooling fluid to the bubble. The pressure chamber includes an upstream end wall sealed around the die head outlet, and extending outward from the seal; a side wall movable between a closed position for controlling air flow from a chamber volume surrounding the bubble to the atmosphere, and an open position for permitting air flow from the chamber volume to the atmosphere. The upstream end wall has an inlet for receiving air from an air supply, and an outlet in fluid communication with the inlet and configured to direct the air into the chamber volume to pressurize the chamber volume when the side wall is in the closed position.

A ram extrusion apparatus including a die having several thermal zones, a hopper for introducing a granular polymer resin to the die, and a ram for moving the granular polymer resin through the thermal zones of the die and out from an outlet end thereof at a temperature above the crystalline melt temperature of the polymer resin. The hopper may be designed to deliver the polymer resin into a resin inlet of the die in a plurality of specifically metered amounts which may vary across a width of the resin inlet end of the die. The apparatus may further include one or more finishing tables positioned after the outlet end of the die for receiving and moving the extruded resin away from the outlet end of the die so that there is no backpressure on the extruded resin, and which provide compression force and even cooling to the extruded resin.

A ram extrusion apparatus including a die having several thermal zones, a hopper for introducing a granular polymer resin to the die, and a ram for moving the granular polymer resin through the thermal zones of the die and out from an outlet end thereof at a temperature above the crystalline melt temperature of the polymer resin. The hopper may be designed to deliver the polymer resin into a resin inlet of the die in a plurality of specifically metered amounts which may vary across a width of the resin inlet end of the die. The apparatus may further include one or more finishing tables positioned after the outlet end of the die for receiving and moving the extruded resin away from the outlet end of the die so that there is no backpressure on the extruded resin, and which provide compression force and even cooling to the extruded resin.

The invention describes a method for the production and further processing of a film tube (6), in which method a plastic melt is transferred into a cylindrical melt by means of an extrusion die (4), the melt flow is drawn out through an annular gap (5) associated with the extrusion die (4) in order to form the film tube (6), and at least one temperature-controlled volume flow comprising at least one fluid is conducted by means of a temperature control device (8) onto the outer periphery of the film tube (6), wherein the temperature control device (8) is divided into peripheral segments, wherein a volume flow of different magnitude and/or different temperature is produced by means of each peripheral segment such that the temperature control of the film tube (6) differs over the periphery of the film tube, and wherein the film tube (6) is flattened by means of a flattening device (9), the flattening device (9) being rotated in relation to the extrusion die (4). A first volume flow in at least one peripheral segment of the temperature control device (8) differs from the volume flow of other peripheral segments so that at least one thick point (13) is produced on the film tube, wherein the first volume flow is produced by means of adjacent peripheral segments in succession, wherein the first volume flow is produced by means of the corresponding at least one peripheral segment in such a way that the first volume flow is adapted to the rotation of the flattening device (9) such that the at least one thick point (13) assumes substantially the same position in relation to the flattening device (9).

A polyetheretherketone pipe of length greater than 250 meters and a residual stress of less than 5 MPa may be made using a calibrator device 2 which includes a cone shaped opening 6 arranged to receive a molten extruded pipe shaped polymer. Attached to the front member 4 is a vacuum plate 14a and successive vacuum plates 14b-14h are attached to one another to define an array of vacuum plates, the vacuum plates being arranged to allow a vacuum to be applied to a pipe precursor passing through opening 16. The vacuum plates 14 also include temperature control means for heating or cooling the plates and therefore heating or cooling a pipe precursor passing through the openings. With a vacuum applied to opening 6, 16 and heating/cooling the plates, an extruded hot plastics pipe is inserted into calibrator 2 via opening 6 and conveyed through opening 16 in plates 14, whereupon it is urged by the vacuum against the cylindrical surface defined by plates 14 to maintain its shape and the temperature of each plate is controlled to control the rate of cooling of the pipe precursor passing through. The pipe may be cooled at a relatively slow rate so that a pipe made from a relatively fast crystallising polymer crystalises and the crystallinity of the pipe along its extent and throughout its thickness is substantially constant.

An acrylic rubber bale excellent in storage stability and processability, a method for producing the same, a rubber mixture obtained by mixing the acrylic rubber bale, and a rubber cross-linked product of the rubber mixture are provided. The acrylic rubber bale according to the present invention includes an acrylic rubber having a reactive group and a weight average molecular weight (Mw) of 100,000 to 5,000,000, wherein an amount of gel insoluble in methyl ethyl ketone is 50% by weight or less, and pH is 6 or less.

An exemplary method of, for instance, forming a baffle or reinforcer includes extruding an expandable material to have a particular cross-sectional profile, inserting the expandable material into a molding tool, cutting the expandable material to a predetermined length within the molding tool, and overmolding a carrier material onto a portion of the expandable material within the molding tool.