A device arranged in the cooling ring of an apparatus for the production of blown films in order to adjust the thickness profile thereof is disclosed. The device includes a plurality of equally spaced motor-driven actuators that adjust the flow rate of the flow of a cooling fluid directed towards a forming cone, as well as a plurality of equally spaced resistances provided with finned dissipators arranged in the path of the cooling flow. In this way, the device combines the characteristics of low power consumption and high adjustment velocity of a volumetric device with the higher angular resolution achievable through the heating elements of a thermal device, and all of this with an operating method that prevents the risks of bubble instability or adhesion, achieves a high energy efficiency and guarantees a wide thickness adjustment range.

The present invention provides a multilayer packaging film characterized by an improved sealability even through contamination with excellent shrinkability good optics and strength without using internal layers of stiff resins and cross-linking, to flexible containers made therefrom, such as bags, pouches and the like, useful for packaging articles, in particular food items.

An air flow controller includes: a box-shaped body cover that is disposed above and/or below a film running surface to be adjacent to an upstream side of an entrance of a tenter oven in a film running direction and/or a downstream side of an exit of the tenter oven in the film running direction, the box-shaped body cover extending in the film running direction and having a surface facing the film running surface and being open. The box-shaped body cover includes at least one partition structural body in the box-shaped body cover, the partition structural body extending in a width direction of the film and separating inside of the box-shaped body cover into a plurality of chambers, and each of at least two of the chambers is provided with an air discharge mechanism configured to discharge air in a corresponding chamber.

An air flow controller includes: a box-shaped body cover that is disposed above and/or below a film running surface to be adjacent to an upstream side of an entrance of a tenter oven in a film running direction and/or a downstream side of an exit of the tenter oven in the film running direction, the box-shaped body cover extending in the film running direction and having a surface facing the film running surface and being open. The box-shaped body cover includes at least one partition structural body in the box-shaped body cover, the partition structural body extending in a width direction of the film and separating inside of the box-shaped body cover into a plurality of chambers, and each of at least two of the chambers is provided with an air discharge mechanism configured to discharge air in a corresponding chamber.

In order to provide a polyethylene sealant film having great strength and good heat sealability, despite being thin, a multilayer polyethylene sealant film is produced by a method including coextruding and stretching a sealant layer formed of a low density polyethylene resin or linear low density polyethylene resin and an orientation layer including a polyethylene resin having a melting point higher than the sealant layer, by an inflation method at a temperature higher than the melting point of the sealant layer and higher than the Vicat softening temperature, but lower than the melting point of the orientation layer.

In order to provide a polyethylene sealant film having great strength and good heat sealability, despite being thin, a multilayer polyethylene sealant film is produced by a method including coextruding and stretching a sealant layer formed of a low density polyethylene resin or linear low density polyethylene resin and an orientation layer including a polyethylene resin having a melting point higher than the sealant layer, by an inflation method at a temperature higher than the melting point of the sealant layer and higher than the Vicat softening temperature, but lower than the melting point of the orientation layer.

A method of forming a blown film comprising extruding a molten composition through a die opening to form a film; wherein the molten composition comprises at least one polyethylene and within the range from 0.10 wt % to 10 wt % of a cyclic-diene terpolymer by weight of the composition; causing the film to progress in a direction away from the die opening; cooling the film at a distance from the die opening, the distance adjusted to effect the properties of the film; and isolating a blown film therefrom.

A method of forming a blown film comprising extruding a molten composition through a die opening to form a film; wherein the molten composition comprises at least one polyethylene and within the range from 0.10 wt % to 10 wt % of a cyclic-diene terpolymer by weight of the composition; causing the film to progress in a direction away from the die opening; cooling the film at a distance from the die opening, the distance adjusted to effect the properties of the film; and isolating a blown film therefrom.

The present invention relates to a process for producing a polymer film (P) comprising a polyamide composition (PC) by extruding the polyamide composition (PC) through an annular die and then stretching the tube thus obtained by blowing in air. The present invention further relates to the polymer film (P) obtainable by the process of the invention and to a process for packaging foodstuffs with the polymer film (P).

The present invention relates to a process for producing a polymer film (P) comprising a polyamide composition (PC) by extruding the polyamide composition (PC) through an annular die and then stretching the tube thus obtained by blowing in air. The present invention further relates to the polymer film (P) obtainable by the process of the invention and to a process for packaging foodstuffs with the polymer film (P).