I. Definition and application of plastic film is a film made of polyvinyl chloride, polystyrene, polyethylene, polypropylene and other resins, plastic Film and plastic packaging products account for an increasing share of the market and are widely used in food, medicine, cosmetics, daily necessities, chemical and other industries, among them, beverage packaging, quick-frozen food packaging, steamed food packaging and fast food packaging account for the largest proportion in the food packaging industry.
At the same time, the wide use of plastic film has brought great convenience to our life.
II. Classification and performance parameters of packaging and printing plastic films 1. BOPP Films (Biaxially oriented polypropylene film)
BOPP Film is the abbreviation of biaxially oriented polypropylene film. BOPP Film is prepared by coextrusion of polypropylene particles to form a sheet and then stretching in both vertical and horizontal directions. The thickness is 20 ~ 40μm or so. .
BOPP film is divided into BOPP ordinary film, BOPP smoke film, BOPP extinction (Matte)
Film, BOPP heat sealing film, BOPP Pearl film, BOPP electrical film, BOPP anti-counterfeiting base film and BOPP transfer film. 2, PE film (Polyethylene film)PE film is divided into LDPE (Low density PE)And HDPE (High density PE).
Low density PE is generally made by blow molding and tape casting. It is a translucent, shiny and soft film with excellent chemical stability, heat sealing, water resistance and moisture resistance, it is resistant to freezing and can be boiled in water. Its main disadvantage is its poor barrier to oxygen. It is often used as an inner film of composite flexible packaging materials.
High density PE adds 25-
30% rivet metal, mainly acid and alkali resistance, organic solvent resistance, low temperature resistance, the main disadvantage is easy to age, difficult to print.
Due to the poor printing performance of low density PE and poor adhesion to ink and adhesive, surface treatment is required before printing and compounding. 3, PET film (Polyester film)
Polyester film is a film material made of polyethylene terephthalate as raw material, thick sheets are formed by extrusion method, and then biaxially stretched.
It is a colorless, transparent and shiny environment-friendly film with a transverse shrinkage of more than 70%, a longitudinal shrinkage of less than 3%, and a thickness of generally 30-
70 micron, especially for the shrinkage of special-shaped bottles, is one of the products with greater advantages of Hongtai packaging products factory. 4, Nylon/PA (Nylon film)
Nylon film is a very tough film with good transparency, good luster, high tensile strength, high tensile strength and good sealing performance. It is used for nozzle bags and vacuum bags for liquid packaging. 5, CPP Film (Cast Polypropylene film)
CPP Film is a polypropylene film produced by tape casting process. It has excellent transparency, uniform thickness and uniform vertical and horizontal performance. It is generally used as the inner layer material of composite film. Specific gravity: 0. 92, common thickness: 1. Above 9C.
CPP Films can be divided into ordinary CPP and cooking grade CPP. 6. VMPET (Aluminized film)
At present, the most widely used aluminized films are mainly polyester aluminized films (VMPET)And CPP aluminized film (VMCPP).
Aluminized film has both the characteristics of plastic film and metal. Its specific gravity is 1. 4, the common thickness is 1. 2C.
The function of aluminizing on the surface of the aluminized film is to block light and prevent ultraviolet radiation, which not only prolongs the shelf life of the contents, but also improves the brightness of the film, replacing aluminum foil to a certain extent, it also has low price, beautiful appearance and good barrier performance. Therefore, aluminized film is widely used in composite packaging. 7, AL (Pure aluminum film)
Pure aluminum film is opaque, has strong air barrier performance, anti-oxidation, waterproof and moisture-proof, and is more expensive than aluminum plating, with a specific gravity of 2. 6, the common thickness is 0. 7C.
It meets the hygienic standards for food and drug packaging and is usually used for packaging such as vacuum packaging bags and mask bags.