A method of manufacturing containers consisting of a substantially stiff outer container and a readily deformable inner bag of first and second thermoplastic plastic materials, where the inner bag is detached from the wall of the outer container, includes the step of the excess material is supplied again to the first screw conveyor, which mixes the excess material with the first thermoplastic plastic material and supplies it to the extruder nozzle, wherein the first thermoplastic plastic material has a lower viscosity in the molten state than the excess material so that the outer layer of the extruded tube consists only of the first thermoplastic plastic material.

Medical tube can have a continuous inner layer having a continuous outer layer thereon, in which the inner layer includes a polyolefin such as a polyethylene or polypropylene or a functionalized polyolefin. The outer layer can include a thermoplastic polymer such as one or more of, or a blend including, a thermoplastic polyurethane (TPU), a thermoplastic olefin (TPO), a thermoplastic elastomer (TPE), a styrene-containing thermoplastic elastomer (S-TPE), a polyolefin elastomer (POE), a styrenic blocking copolymer (SBC). Advantageously, the outer layer and/or the inner layer do not include polyvinyl chloride. Such tubing can be used as medical device such as with infusion sets.

The use of PEKK for lowering the CO.sub.2 and H.sub.2S permeability of a part intended to enter into contact with a petroleum effluent. Also, a pipe for transporting a petroleum effluent, including a layer intended to be in contact with the petroleum effluent, wherein the layer intended to be in contact with the petroleum effluent comprises PEKK and has a CO.sub.2 permeability at 130° C. of less than 10.sup.−8 cm.sup.3, for a thickness of 1 cm and a surface area of 1 cm.sup.2 and per second and bar of CO.sub.2 pressure and/or an H.sub.2S permeability at 130° C. of less than 10.sup.−8 cm.sup.3 for a thickness of 1 cm and a surface area of 1 cm.sup.2 and per second and bar of H.sub.2S pressure, the amount of CO.sub.2 and H.sub.2S being measured by GC, respectively. Lastly, a number of methods for manufacturing such a pipe.

A polymer optical fiber is provided which shows improved hydrolytic stability. This fiber comprises a polymeric optical core and cladding layer, surrounded by a polymeric overcladding layer which comprises a miscible blend of one or more hydrolytically stable amorphous polymers. By varying the ratios of the component polymers in the overcladding blend, the glass transition temperature and the coefficient of thermal expansion of the overcladding layer may be tuned to optimize the attenuation and bandwidth of the plastic optical fiber.

There is provided a hollow extrusion-molded material formed by drawdown molding of a resin composition, the resin composition including, as a base resin, an ethylene-ethyl acrylate copolymer, or an ethylene-ethyl acrylate copolymer and linear low-density polyethylene, the resin composition including a bromine-based flame retardant, antimony trioxide and magnesium hydroxide, wherein a composition ratio between the ethylene-ethyl acrylate copolymer and the linear low-density polyethylene, a content of the bromine-based flame retardant, a content of the antimony trioxide, and a content of the magnesium hydroxide are within specified ranges. There are also provided a crosslinked polymer of the hollow extrusion-molded material, and a heat-shrinkable tube and a multilayer heat-shrinkable tube obtained from the crosslinked polymer.

A formulation for producing a polymeric material including high-density polyethylene, a chemical blowing agent, and other optional components is described.

Systems and methods can be used to produce fibers with external corrugations, internal corrugations, or both. These fibers can be used, for example, in hollow fiber membrane modules.

Systems and methods can be used to produce fibers with external corrugations, internal corrugations, or both. These fibers can be used, for example, in hollow fiber membrane modules.

The use of PEKK for lowering the CO.sub.2 and H.sub.2S permeability of a part intended to enter into contact with a petroleum effluent. Also, a pipe for transporting a petroleum effluent, including a layer intended to be in contact with the petroleum effluent, wherein the layer intended to be in contact with the petroleum effluent comprises PEKK and has a CO.sub.2 permeability at 130 C. of less than 10.sup.8 cm.sup.3, for a thickness of 1 cm and a surface area of 1 cm.sup.2 and per second and bar of CO.sub.2 pressure and/or an H.sub.2S permeability at 130 C. of less than 10.sup.8 cm.sup.3 for a thickness of 1 cm and a surface area of 1 cm.sup.2 and per second and bar of H.sub.2S pressure, the amount of CO.sub.2 and H.sub.2S being measured by GC, respectively. Lastly, a number of methods for manufacturing such a pipe.

The method for forming from a round shaped cylinder to a square shaped cylinder or flat sheet which can be inserted in a square or rectangular shape metal pipe includes initiating turning of a heated mandrel, extruding heated polymer, wrapping while compressing a first layer of heated polymer or mesh, disposing a mesh or polymer layer over the cylinder encapsulating the cylinder on the turning mandrel while simultaneously laying a second layer of heated polymer over the turning mandrel and compressing the layer of heated polymer into the mesh layer and the mesh layer into the first layer of heated polymer simultaneously, and repeating the layering of the heated polymer and mesh layer until a desired wall thickness is reached.