Abstract: Apparatus for longitudinal orientation of thermoplastic film material (4) comprises a width-reduction zone upstream of the longitudinal stretching zone, through which the width of the film is gradually reduced so as to allow longitudinal stretching without necking. The width-reduction zone comprises at least one, preferably several, pairs of pleating rollers (16, 17) comprising intermeshing grooves or discs for pleating the material, the length of said width reduction zone preferably being less than 3 times the original width of the film. The width-reducing zone has upstream (14) and downstream (15) rollers or roller assemblies, with curved axes and optionally also conveyor belts for providing smooth width reduction. Longitudinal stretching is preferably between at least two, and preferably more than two, pairs of stretching rollers (9, 10, 11, 12) which are relatively close together.

Abstract: A laminate of thermoplastic polymeric films comprises at least one fluted ply A and at least one substantially flat ply B, adhered to one another in bonded zones along the flute crests. The wavelength of the flutes is preferably no more than 3 mm. Ply A has a generally uniform thickness or can have attenuated zones of lessor thickness extending parallel to the flute direction, each bonded zone being located mainly within an attenuated zone. The flutes can be sinuous with crests on both sides of ply A and can be adhered on each side to a ply B, in which case, attenuated zones can be on both sides and can have different widths. The flutes can be filled with filler material, including reinforcement strands, and one or both sides can be perforated. The method and apparatus employ aligned grooved fluting rollers and a grooved laminating roller.

Abstract: Flexible tubular film (10) is helically cut into a flat strip by unwinding the tubular film in flattened form by a tumbling unwinder (1), advancing the flat film tube to a tube expansion zone (17) in which the flat tube is expanded into a circular cylindrical tube and is passed axially over a hollow mandrel (14) slightly lower in external diameter than the diameter of the expanded tube to be cut by knife (18) helically while on the mandrel into a flat strip that is removed at an angle to the mandrel axis. The flat tube is longitudinally stretched by stretching rollers (107-112), which tumble with the tumbling unwinder. The apparatus further comprises stabilization means for stabilizing the orientation applied by the tumbling stretching rollers, applied to the helically cut film strip after it has been drawn from the mandrel.

Abstract: A laminate of thermoplastic film materials exhibiting throughgoing porosity and comprising plies A and B, A having an inner surface A1 partly in contact with B and an outer surface A2, and B having an inner surface BI partly in contact with A and an outer surface B2, A and B consisting of continuous material except for a multitude of perforations in each ply, whereby essentially no perforation in A corresponds directly to a perforation in B, the lamination between A and B on surfaces A1 and B1 being a) through a coextruded lower melting lamination layer on A and/or B and b) established in such discontinuous manner that there is formed a channel system between A1 and B1 connecting the majority of the perforations in A each with at least one of the perforations in B, and connecting the majority of the perforations in B each with at least one of the perforations in A is provided in addition to a process and apparatus for producing such a laminate.

Abstract: Method and apparatus for longitudinal orientation of thermoplastic film material (4) comprises a width-reduction zone upstream of the longitudinal stretching zone, through which the width of the film is gradually reduced so as to allow longitudinal stretching without necking. The width-reduction zone comprises at least one, preferably several, pairs of pleating rollers (16, 17) comprising intermeshing grooves or discs for pleating the material, the length of said width reduction zone preferably being less than 3 times the original width of the film. The width-reducing zone has upstream (14) and downstream (15) rollers or roller assemblies, with curved axes and optionally also conveyor belts for providing smooth width reduction. Longitudinal stretching is preferably between at least two, and preferably more than two, pairs of stretching rollers (9, 10, 11, 12) which are relatively close together.

Abstract: Flexible tubular film (10) is helically cut into a flat strip by unwinding the tubular film in flattened form by a tumbling unwinder (1), advancing the flat film tube to a tube expansion zone (17) in which the flat tube is expanded into a circular cylindrical tube and is passed axially over a hollow mandrel (14) slightly lower in external diameter than the diameter of the expanded tube to be cut by knife (18) helically while on the mandrel into a flat strip that is removed at an angle to the mandrel axis. The flat tube is longitudinally stretched by stretching rollers (107-112), which tumble with the tumbling unwinder. The apparatus further comprises stabilization means for stabilizing the orientation applied by the tumbling stretching rollers, applied to the helically cut film strip after it has been drawn from the mandrel.

Abstract: A film material formed of thermoplastic polymer material is processed so as to have linearly extending regions (A) linked together by linearly extending webs (B), regions (A) and webs (B) each being oriented, the dominant direction of orientation in regions (A) forming an angle (V) to the direction on which (A) extends and webs (B) comprising arrays of linear furrows of thinner material or splits forming angles (U) higher than (V) to the direction in which (A) extends. The method of producing the new film involves passing an orientated film through a pair of intermeshing grooved rollers to cold-stretch the film in a direction at an angle to the predominant original orientation, at least one of the grooved rollers having crests with sharp edges to form the division between regions A and webs B and to stretch the material to form webs B while stretching the material less or not at all to form regions A. Preferably at least one of the grooved rollers has crests with a waved surface shape.

Abstract: A film material formed of thermoplastic polymer material is processed so as to have linearly extending regions (A) linked together by linearly extending webs (B), regions (A) and webs (B) each being oriented, the dominant direction of orientation in regions (A) forming an angle (V) to the direction on which (A) extends and webs (B) comprising arrays of linear furrows of thinner material or splits forming angles (U) higher than (V) to the direction in which (A) extends. The method of producing the new film involves passing an orientated film through a pair of intermeshing grooved rollers to cold-stretch the film in a direction at an angle to the predominant original orientation, at least one of the grooved rollers having crests with sharp edges to form the division between regions A and webs B and to stretch the material to form webs B while stretching the material less or not at all to form regions A. Preferably at least one of the grooved rollers has crests with a waved surface shape.

Abstract: A method of forming a film (1) of molten polymer material, by extruding said material in a direction (2) out of a narrow exit slot (3), which is an integral part of a wider die chamber (4) of which the major dimension of extension is parallel with the major dimension of the exit slot (3), characterized in that the molten polymer material is formed into one or more flows generally parallel with said major dimension of the exit slot (3), each said flow being pumped in a re-circulating arrangement from the chamber inlet (7) to the outlet (8) through conduits connecting the inlet to the outlet, while fresh molten polymer material is administered from a reservoir into each re-circulating flow.

Abstract: A method of helically cutting a tubular film of thermoplastic material, in which a film in lay flat form, discharged from a reel, is brought to rotate around the middle axis of the film by means of rotating unwind devices, and while the rotating tube proceeds over the mandrel it is cut to non-tubular form by a knife, the position of which is fixed in relation to the surroundings, and the cut film is taken off from the mandrel, characterized in that the inflated film while being forwarded towards the mandrel or while it passes the upstream end of the mandrel, or both, is supported by driven support means placed around the outside of the tubular film, the movement of the support means being adapted to fit with the combined rotation and forwarding movement of the film.

Abstract: Crosslaminates of thermoplastic films have at least one of the films formed as a fluted structure, and two films are laminated to one another in such a manner that pockets are formed which contain gas. The pockets allow passage of gas between at least two adjacent flutes, whereby the product has an improved handle, and bags formed of the laminate have good stacking properties when filled with coarse particulates. The flute pitch is generally no more than 3 mm, while the pocket length is less than 50 mm. The bonding method involves spot bonding between the films, achieved by adhering the films together between crown portions of bosses on one film with molten material on the other film under a low pressure process, for instance achieved by provision of air pressure through adaptation of production apparatus, for instance die portions.

Abstract: A crosslaminate is formed from two oriented plies of thermoplastic polymer material, arranged so that their orientation directions cross one another, the plies being heat sealed together. Each ply is semi-fibrillated, that is consist of linear thin regions of biaxially oriented material and thicker linear bosses between the thinner regions. The webs are sealed primarily through bonds formed at the intersection of the bosses (thicker regions). The array of bosses has a division less than 2 mm. The laminate has improved aesthetic and strength properties. A method for forming the crosslaminate involves segmental stretching of the material to form the thinner regions, and apparatus comprising intermeshing grooved stretching rollers having sharp-edged crests is described.

Abstract: A method of manufacturing an oriented film of thermoplastic polymer material comprises extrusion of a film in tubular form from an extrusion die, orienting the film in a main direction of orientation during the haul-off from the die while in molten or semi-molten state, the direction being at an angle between 0 and 45-to the axis of the tube, followed by cutting of the tube at an angle to its main degree of orientation to form a web having an orientation of no less than 20 to its longitudinal direction, which method involves segmental stretching of the film to form an array of linear bosses (1), being of thicker material, integrally connected by thinner webs (2), said bosses and webs extending in a direction which is generally parallel with the direction of orientation, forming an acute angle to the longitudinal direction of the web, the method involving, after segmental stretching and cutting, shearing of the bosses along one another under re-orientation in the connecting webs, to increase the angle at which

Abstract: A crosslaminate is formed from two oriented plies of thermoplastic polymer material, arranged so that their orientation directions cross one another, the plies being heat sealed together. Each ply is semi-fibrillated, that is consist of linear thin regions of biaxially oriented material and thicker linear bosses between the thinner regions. The webs are sealed primarily through bonds formed at the intersection of the bosses (thicker regions). The array of bosses has a division less than 2 mm. The laminate has improved aesthetic and strength properties. A method for forming the crosslaminate involves segmental stretching of the material to form the thinner regions, and apparatus comprising intermeshing grooved stretching rollers having sharp-edged crests is described.

Abstract: Method and apparatus for longitudinal orientation of thermoplastic film material (20) comprises a width-reduction zone upstream of the longitudinal stretching zone (9, 10), through which the width of the film is gradually reduced so as to allow longitudinal stretching without necking. The width-reduction zone comprises at least two sets of pleating rollers (7, 1) comprising intermeshing grooves or discs for pleating the material. The downstream (1) rollers comprise a mini-roller defined by the following measures a) the pitch of the corrugations, measured from middle of tip to middle of each neighbouring tip is 20 mm or less; b) the perimeter from middle of a tip to the middle of each neighbouring tip measured along the corrugated roller surface, divided by the said pitch is in the range between 1.10 and 1.80; and c) the diameter of the mini-roller, measured at the tips of the corrugations, is at the highest 4 times the said pitch.

Abstract: A laminate of thermoplastic film materials exhibiting throughgoing porosity and comprising plies A and B, A having an inner surface A1 partly in contact with B and an outer surface A2, and B having an inner surface BI partly in contact with A and an outer surface B2, A and B consisting of continuous material except for a multitude of perforations in each ply, whereby essentially no perforation in A corresponds directly to a perforation in B, the lamination between A and B on surfaces A1 and B1 being a) through a coextruded lower melting lamination layer on A and/or B and b) established in such discontinuous manner that there is formed a channel system between A1 and B1 connecting the majority of the perforations in A each with at least one of the perforations in B, and connecting the majority of the perforations in B each with at least one of the perforations in A is provided in addition to a process and apparatus for producing such a laminate.

Abstract: A method and apparatus for carrying out the method are for forming a sheet or film of thermoplastic polymer alloy by extruding an intimate blend of incompatible polymer materials, such as polypropylene dispersed in LLDPF, through an extruding die and stretching after extrusion.

Abstract: Flexible tubular film (10) is helically cut into a flat strip by unwinding the tubular film in flattened form by a tumbling unwinder (1), advancing the flat film tube to a tube expansion zone (17) in which the flat tube is expanded into a circular cylindrical tube and is passed axially over a hollow mandrel (14) slightly lower in external diameter than the diameter of the expanded tube to be cut by knife (18) helically while on the mandrel into a flat strip that is removed at an angle to the mandrel axis. The flat tube is longitudinally stretched by stretching rollers (107-112), which tumble with the tumbling unwinder. The apparatus further comprises stabilization means for stabilizing the orientation applied by the tumbling stretching rollers, applied to the helically cut film strip after it has been drawn from the mandrel.

Abstract: New cross-laminates are formed of films of which at least two are uniaxially or unbalanced biaxially oriented, in which the main direction of orientation in one of these films crosses the main direction of orientation in the other one, having modifications, made in a suitable pattern, of the surface properties of the two films on the surfaces which are inside the laminate and are bonded to each other. The internally arranged surface layers of the films comprise an array of strands (101, 102) of coextruded material and the films are arranged so that the arrays of the two films cross one another. The strands may be used to control adhesion between the films and reduce the tendency to delaminate on repeated flexing, making a laminate suitable for use as a tarpaulin.

Abstract: A laminate of thermoplastic polymeric films comprises at least one fluted ply A and at least one substantially flat ply B, adhered to one another in bonded zones along the flute crests. The wavelength of the flutes is preferably no more than 3 mm. Ply A has a generally uniform thickness or can have attenuated zones of lessor thickness extending parallel to the flute direction, each bonded zone being located mainly within an attenuated zone. The flutes can be sinuous with crests on both sides of ply A and can be adhered on each side to a ply B, in which case, attenuated zones can be on both sides and can have different widths. The flutes can be filled with filler material, including reinforcement strands, and one or both sides can be perforated. The method and apparatus employ aligned grooved fluting rollers and a grooved laminating roller.