A micro-voided film comprising high density polyethylene having a molecular weight of at least about 200,000, and low aspect ratio filler having a mean particle size from about 1 to about 25 microns. The film has a thickness of from about 10 to about 75 microns and a void fraction of from about 0.60 to about 0.75. The micro-voided film is made by a process comprising extruding the composition into a film having a thickness of from about 50 to about 300 microns, and orienting the extruded film using a high stalk, blown film process. The process produces a stabilized high stalk for increasing the production rate of blown, high molecular weight polyethylene, while increasing the film's physical and mechanical properties. The high stalk can be stabilized by application of high velocity, low volume flow rate of air over the interior and exterior surfaces of the extruded film.

The present invention relates to a method for producing a biodegradable resin expanded sheet, by which a biodegradable resin expanded sheet immediately after extrusion is brought into a predetermined cooled state in an extrusion expansion method, whereby good formability can be exerted.

An internal cooling tower for a film blowing line with one or more superimposed cooling air nozzles designed such that the entrainment of droplets consisting of low-molecular components of the raw material that diffuse during the film blowing process from the film into the flow of cooling air is prevented. This is achieved in that at the height of the nozzle gap, the top surface of the cooling air nozzles has a grooved contour both on the inside and the outside.

The invention relates to a film product (10) for packing products, particularly liquids (200), pasty and/or pourable materials, in sealed film packages (100), comprising at least two film layers (20a, 20b), wherein the outwardly facing film layer (20a) is thermally stable, and the inwardly facing film layer (20b) is sealable, and both film layers (20a, 20b) are produced in a water-cooled coextrusion blow molding process.

The invention relates to a blown film line for generating a blown film with at least one extruder for generating at least one melt strand, at least one distribution tool for converting the at least one melt strand into a circulating melt layer, an outlet nozzle for outputting the at least one melt layer, wherein this melt layer forms the blown film, and at least one device for subjecting the blown film to at least one fluid stream, in particular an air stream, for cooling the blown film. At least one pressure-providing device is furnished, with which the blown film may be brought to the device for subjecting the blown film to a fluid stream by means of at least one overpressure and/or one underpressure.

A micro-voided film comprising high density polyethylene having a molecular weight of at least about 200,000, and low aspect ratio filler having a mean particle size from about 1 to about 25 microns. The film has a thickness of from about 10 to about 75 microns and a void fraction of from about 0.60 to about 0.75. The micro-voided film is made by a process comprising extruding the composition into a film having a thickness of from about 50 to about 300 microns, and orienting the extruded film using a high stalk, blown film process. The process produces a stabilized high stalk for increasing the production rate of blown, high molecular weight polyethylene, while increasing the film's physical and mechanical properties. The high stalk can be stabilized by application of high velocity, low volume flow rate of air over the interior and exterior surfaces of the extruded film.

The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process, comprised of one or more enclosures with one or more respective cavities that directly receive a portion of cooling gas emanating from one or more associated cooling elements. Each enclosure includes a port containing a variable exhaust device and optional flow buffer, acting to maintain a pressure differential between the cavity and an adjacent inside volume of the molten film tube, adjustable to optimize molten film tube stability cooling element efficiency and spaced apart dimension between cooling elements. Additionally, at least one cooling element is provided, comprised of a divergent cooling element with a divergent cooling interface containing a cooling gas deflector spaced adjacent to the molten film tube and providing an expelled cooling gas.