RELATIONSHIPS BETWEEN THE STRUCTURE AND MECHANICAL PROPERTIES OF POLYETHYLENE BLOWN FILMS

Abstract

The production of polyethylene blown films, which are used for the production of packaging, such as different types of bags and pouches, is a very complex process. With this procedure, the molten plastic mass is extruded through a ring tool and forms a thick-walled cylinder. The still heated and softened cylinder expands by blowing air into a hollow cylinder of a certain diameter and wall thickness. The quality of the film is affected by adjusting and matching the height of the cooling line, the blowing ratio, the working speed and the capacity of the extruder. The quality of the film can also be affected by add of additives in the extrusion process. In this way, the material gets the desired color, firmness, elasticity, static electricity is eliminated, and it is possible to influence other properties as well. Commercially available PELD, PEHD, recycled PE material that was not used for original purposes (Post Industrial Recycled Materials) and additives were used for the production of films. By mixing fresh polyethylene, additives and recycled polyethylene in different ratios, products with different mechanical characteristics are obtained.