Introduction of several production processes and characteristics of PE protective film
Posted by Admin | 03 Aug
PE protective film can use a lot of Chinese crafts, today I will give you a better introduction to these crafts, please understand in detail. There are many methods for forming PE protective film, among which the three processes of casting, extrusion and blow molding are more common. The three processes have their own characteristics. This article analyzes the process principles and application fields.
Process principle comparison: Cast film formation is a non-stretched, non-oriented flat-extrusion film produced by melt casting and quenching. There is no obvious orientation structure.
Extrusion method for film formation, there are common uniaxial stretching and biaxial stretching methods, of which biaxial stretching is a production method that has attracted considerable attention in recent years. The basic principle of the biaxial stretching technology is that the high polymer material is first heated and melted and extruded into a thick sheet through the extruder, and then in the appropriate temperature range above the glass transition temperature and below the melting point, the stretching machine is used for a certain degree in the longitudinal direction and the transverse direction. The multiple stretching makes the molecular chains oriented in a plane parallel to the film and arranged in an orderly manner, and then heat setting under tension to fix the oriented macromolecular structure, and finally cooling and subsequent processing to form a film.
Film formation by blow molding is usually made by extrusion blow molding. The material is plasticized and extruded to form a tube blank and blow molded, and then cooled, drawn, and coiled. The blown film is oriented.
Different from the above three process forming methods, the conductivity of the film is significantly different; at the same time, compared with the unstretched film, the barrier performance of the stretched film is improved, the permeability to gas is reduced, and the optical performance, transparency and surface gloss are improved. Good size temperature, good thickness uniformity.
Application field comparison: Take PE protective film, PVC protective film and ordinary PP film as examples for comparison
PE protective film: The product has the characteristics of transparency, softness, good barrier properties and mechanical adaptability, high temperature cooking (cooking temperature above 120℃), low temperature heat sealing (heat sealing temperature less than 125℃), etc. Mainly used for industrial protection, acrylic panels, glass panels and other composite packaging inner layer substrate, can protect the product life, increase the aesthetics. It can also be used for the surface layer and compartment of stationery products, and can also be used as auxiliary film, such as loose leaves and labels for photos and collectibles.
PVC protective film: It has excellent printing performance, can be compounded with paper, PET and other substrates, has high definition and gloss, excellent ink absorption and coating adhesion, high tensile strength, and excellent grease barrier properties , Low electrostatic characteristics, etc. It is widely used in the field of printing and compounding, and at the same time as a packaging material in tobacco and other aspects.
Ordinary PP protective film: Because of its simple process and low cost, its optical performance is slightly lower than that of CPP and BOPP. Mainly used for the outer packaging of snacks, bread, textiles, folders, record covers, sports shoes, etc.
Among them, PE protective film and PVC protective film have improved composite performance and wider application. After composite, they are moisture-proof, transparent, crisp, widely used, and have obvious advantages in industry competitiveness. They are currently used in many applications.