According to the raw materials and stretching process used to produce polyester film

1. Biaxially oriented polyester film (BOPET for short) is made of bright material (also called big bright material, that is, the content of titanium dioxide in the raw material polyester chip is 0.1%, after drying, melting, extrusion, casting and High-grade film stretched vertically and horizontally, widely used). BOPET film has the characteristics of high strength, good rigidity, transparency, and high gloss; it is odorless, tasteless, colorless, non-toxic, and outstanding toughness; its tensile strength is 3 times that of PC film and nylon film, and its impact strength is BOPP 3-5 times the film, it has excellent abrasion resistance, folding resistance, pinhole resistance and tear resistance, etc.; heat shrinkage is very small, at 120 ℃, only 1.25% shrinkage after 15 minutes; Good antistatic properties, easy to vacuum aluminum plating, can be coated with PVDC, thereby improving its heat-sealability, barrier properties and printing adhesion; BOPET also has good heat resistance, excellent cooking resistance, low temperature freezing resistance Performance, good oil resistance and chemical resistance. Except for nitrobenzene, chloroform, and benzyl alcohol, BOPET film cannot be dissolved by most chemicals. However, BOPET will be corroded by strong alkali, so care should be taken when using it. BOPET film has low water absorption and good water resistance, suitable for packaging food with high water content.

2. Uniaxially stretched polyester film (CPET for short) is a film made of semi-dull material (titanium dioxide is added to the raw material polyester chips), which is dried, melted, extruded, cast and stretched longitudinally. The film has the lowest grade and price, and is mainly used for pharmaceutical tablet packaging. Due to the small amount of use, few manufacturers produce on a large scale, accounting for about 5% of the polyester film field. Chinese companies also rarely import, with a standard thickness of 150μm.