The PET thin grains used for packaging are biaxially oriented with controlled stretching. The PET biaxially oriented stretch film uses PET particles extruded at a starting temperature of 250-300 ° C, cooled at 60 ° C, then stretched 2.5-4 times at a stretching temperature of 80-9 ° C and a tensile temperature of 95-115 ° C in the mold direction, and then heat set at 150-230 ° C under the tension of particle stretching. After cooling, it forms a biaxially oriented PET film with the following characteristics:
① Has high transparency and luster, with a light transmittance of 90%,
② Outstanding toughness, its tensile strength is three times that of PC film and nylon 6 film, its impact strength is 3-5 times that of BOPP film, and it has excellent wear resistance, folding resistance, pinhole resistance, and tear resistance;
③ Very low thermal shrinkage, only 1.25% shrinkage after 15 minutes at 120C:
④ PET has good anti-static properties and is easy to vacuum evaporate aluminum. For PET that requires airtightness, PVDC can be coated. KOPET has good heat sealing properties and improves the adhesion of PET orientation film to printing ink. Otherwise, the printing ink should be modified for adhesion in order to produce printed products with good fastness.
BOPET film can be used for heat-resistant, freeze resistant, and detoxifying food packaging: PET film packaging for fruits and vegetables – can be preserved for one year when stored in C. PET is also used for packaging electronic components: PET is used as the surface material for composite film packaging and has good cooking resistance: produced in the United States with a thickness of 0 0127mm PET film with a yield tensile strength of up to 286.8MPa. It can be used in ovens and heat sealed food packaging, and has good gas resistance, diffusion resistance, and oil resistance at 204.4C (400F).
Production of film for packaging using blow molding and extrusion casting methods. The film has inherent resin properties such as toughness, wide temperature range, transparency, ease of processing, and easy coating. PC film is suitable for pharmaceutical and food packaging, cosmetics, and low box winding packaging. PC is the strongest and most rigid thermoplastic, with 90% transparency, resistance to various chemicals, including many acids and chemicals, but some solvents can corrode it. It has good tensile strength and dimensional stability, low absorption, and less shrinkage under temperature changes. Due to its high tensile strength, toughness, and modulus, it does not require the expensive biaxially oriented stretching method to produce oriented films. It only needs to produce ordinary blown or cast films on standard film assembly lines to meet the requirements of packaging performance. It can be bonded with standard water-based or alcohol based adhesives with good bonding strength, and can also be used as a base film for co extrusion coating, or dry composite into laminated films. The fracture strength of PC film can reach over 59MPa and does not degrade below 320C. PC softens at 132C and can reach 176 Embossing and heat sealing at 6~221.1C (350F~430F), it is best to use ultrasonic welding for sealing, and it can be hot formed at the above temperature. It is difficult to hot form the finished PC film. Therefore, for deep stretching with a stretching ratio of 7-10, amorphous PC film can be used to achieve it. The finished PC film cannot heat seal itself without losing its performance, and it does not contain plasticizers or other additives that can easily migrate or smoke during heat sealing.
