A parison tube former utilizes a radial compression heater to heat a very specific portion of a preform tube for stretching. The heater has a plurality of compression dies that form a central cavity for receiving the preform tube. The working surfaces of the compression dies close down onto the outer surface of the preform tube to heat the tube via conduction, which more accurately and precisely heats the preform tube. A first stretched portion of the preform tube is produced by stretching the preform tube after heating. A second portion of the preform tube is then located within the central cavity and is also heated by the radial compression heater and stretched to produce a second stretched portion of the preform tube and an unexpanded portion of the preform tube, or balloon portion of the parison tube.

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.

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.

The invention relates to a process for producing a biaxially oriented pipe by a) forming a polyethylene composition into a tube, wherein the polyethylene composition comprises high density polyethylene (HDPE) and a second polyethylene selected from linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and a combination of LLDPE and LDPE and b) stretching the tube of step a) in the axial direction and peripheral direction to obtain the biaxially oriented pipe.

The invention relates to a process for producing a biaxially oriented pipe by a) forming a polyethylene composition into a tube, wherein the polyethylene composition comprises high density polyethylene (HDPE) and a second polyethylene selected from linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and a combination of LLDPE and LDPE and b) stretching the tube of step a) in the axial direction and peripheral direction to obtain the biaxially oriented pipe.

Disclosed is a composition that comprises or is produced from a first ethylene α-olefin copolymer, a modified first ethylene α-olefin copolymer, and a second ethylene α-olefin copolymer or propylene α-olefin copolymer. Also disclosed is a multilayer film or sheet structure containing at least one barrier layer; at least one predominantly propylene-based layer, at least one predominantly ethylene-based layer, or both; and at least one adhesive layer produced from the composition. Further disclosed is a produced for producing a multilayer structure using the composition as adhesive layer.

Methods for preparing oriented polymer tubes, such as biodegradable polymer tubes suitable for in vivo use, are provided herein. The disclosed methods provide alternatives to the typical extrusion/expansion methods by which oriented polymeric tubes for such uses are commonly produced. Advantageously, the disclosed methods can provide more homogeneous molecular orientation of crystallizable polymers within the tube walls, which can endow such polymeric tubes with enhanced strength (e.g., resistance to compression) and toughness.

Methods for preparing oriented polymer tubes, such as biodegradable polymer tubes suitable for in vivo use, are provided herein. The disclosed methods provide alternatives to the typical extrusion/expansion methods by which oriented polymeric tubes for such uses are commonly produced. Advantageously, the disclosed methods can provide more homogeneous molecular orientation of crystallizable polymers within the tube walls, which can endow such polymeric tubes with enhanced strength (e.g., resistance to compression) and toughness.

The invention relates to a modification process for modifying a biaxially oriented pipe, comprising a) providing a biaxially oriented pipe made by stretching a tube made of a thermoplastic polymer composition in the axial direction and in the peripheral direction, b) placing an insert within an end portion of the pipe, wherein the outer periphery of the cross section of the insert substantially matches the inner periphery of the cross section of the pipe and c) heating the end portion such that the end portion axially shrinks while the inner periphery of the cross section of the end portion is substantially maintained, to obtain a modified biaxially oriented pipe with a thickened end portion.

The invention relates to a modification process for modifying a biaxially oriented pipe, comprising a) providing a biaxially oriented pipe made by stretching a tube made of a thermoplastic polymer composition in the axial direction and in the peripheral direction, b) placing an insert within an end portion of the pipe, wherein the outer periphery of the cross section of the insert substantially matches the inner periphery of the cross section of the pipe and c) heating the end portion such that the end portion axially shrinks while the inner periphery of the cross section of the end portion is substantially maintained, to obtain a modified biaxially oriented pipe with a thickened end portion.