Production process
The five-layer co-extrusion heat shrinkable packaging film is made of linear low-density polyethylene (LLDPE) and copolymer polypropylene (TPP, PPC) as the main raw materials, adding necessary additives, and processed by co-extrusion blow molding. The process is Different from the traditional blow molding process, due to the poor tensile properties of the PP melt state, the traditional blow molding process cannot be used. Instead, the double bubble process is used, which is also known as the Pulandi process in the world. The product is melted and extruded out of the machine, through a specially designed co-extrusion die head, the primary film is formed and then quenched, and then heated for secondary inflation and stretching to make the product.
Main performance
Product specifications
The five-layer co-extruded heat shrinkable film can be produced in various specifications according to the application. The general thickness ranges from 12μm to 30μm. The usual thicknesses are 12μm, 15μm, 19μm, 25μm, etc. The width specifications depend on the volume of the package.
Cold resistance
The five-layer co-extruded heat-shrinkable packaging film remains soft at -50°C without brittleness, and is suitable for storage and transportation of the packaged objects in a cold environment.
Hygienic performance
The raw materials used in the five-layer co-extruded heat-shrinkable packaging film are all environmentally friendly non-toxic materials, and the processing and use process are hygienic and non-toxic, in line with national FDA and USDA standards, and can be used for food packaging.
Application prospects
POF heat-shrinkable packaging film has a wide range of uses, a broad market, and has the advantages of environmental protection and non-toxicity. Therefore, it has been widely valued by developed countries in the world and has basically replaced PVC heat-shrinkable packaging film as the mainstream product of heat-shrinkable packaging materials. The production of this series of products in China began in the mid-1990s. There are more than ten production lines in China, all of which are imported equipment, with a total production capacity of about 20,000 tons. Due to a certain gap between China’s packaging technology and internationally developed countries, the application of three-layer co-extrusion series of heat-shrinkable packaging films in China is still at a preliminary stage, and the scope of application is still relatively narrow. It is limited to beverages, audio-visual products, convenience foods and a small amount of daily chemical products. In a few areas, the annual demand is about 20,000 to 30,000 tons. PVC heat-shrinkable film also occupies a considerable heat-shrinkable packaging market, with huge development potential. With China’s accession to the WTO and its integration with the international market, the gradual increase in packaging requirements for a large number of export commodities, and the rapid development of domestic supermarkets, the application of three-layer co-extruded heat shrinkable packaging film will increase rapidly. It is foreseeable that the three-layer The market prospect of co-extrusion series heat shrinkable film is very broad.