METHOD FOR THE PRODUCTION OF HIGHLY-RESISTANT HIGHLY-SHRINKABLE FIVE-LAYER FILM AND A HIGHLY-RESISTANT HIGHLY-SHRINKABLE FIVE-LAYER FILM

摘要

The invention relates to a method for the production of five-layer highly-resistant, highly-shrinkable film, and a five-layer highly-resistant, highly-shrinkable film, applicable for the packaging of multiple packages with beverages or any other product requiring strong, resistant packaging, which fits tightly to the product. The production method is characterized by the fact that throughout the entire manufacturing process, the temperatures are stabilized in the individual sectors of each product extrusion (А, В, С, D and Е) cylinder and in the extrusion head sector, and in addition, an automatic dosing system for the batch is configured for each extruder, with an accuracy of under 0.1%, after which the plasticized and homogeneous material is fed to the main forming tube, preferably 1.2 mm, which is then blown by air until a specified size of the final film is achieved, the final product sleeve is transferred through an air ring and a calibrator, where a cooling ring feeds air to the surface of the sleeve, cooling the material to under the temperature of softening, for forming and determining the thickness of the film; after this, the sleeve is flattened and wound on a reel by a winder. The film produced this way is characterized by the fact that it consists of А and Е surface layers, their thickness constitutes approximately 10% of the entire layer, separated by А and Е outer layers and В and D layers, their thickness constitutes approximately 20% of the thickness of the entire layer, whereby the А and Е layers consist of a mixture of materials containing 78% low density polyethylene, density 0.921-0.924 g/сm3, melt flow index (MFI) 0.2-0.35 g/10 min, temperature of softening 94оС, 10% metallocene linear PE, density 0.923 g/сm3, MFI 0.9 g/10 min, temperature of softening 1140 cm3.