Production process of PET shrink film
Publish Time: 2024-08-23
The production process of PET shrink film is a complex and delicate process, which involves multiple key steps and the control of process parameters. The following is a detailed analysis of the production process of PET shrink film:
1. Raw material preparation
PET particles: The basic raw material of PET shrink film is PET particles, which are obtained by high temperature and high pressure processing of polyester resin. The production process of PET particles includes multiple processes such as raw material ratio, pre-drying, melting, extrusion, cooling and cutting. Parameters such as temperature, pressure and speed need to be strictly controlled to ensure the quality of particles.
2. PET film extrusion
Extrusion process: After the PET particles are heated and melted, the melted particles are extruded through the spiral propulsion of the extruder to form a flat film. In this process, parameters such as extrusion temperature, extrusion speed and die pressure need to be controlled to ensure the thickness uniformity and surface quality of the PET film.
3. PET film stretching
Stretching process: The PET film obtained by extrusion needs to be stretched to enhance its physical properties. The stretching process is to pass the PET film through a series of rollers and stretch it at a certain temperature to increase the tensile strength and modulus of the film. During the stretching process, parameters such as stretching temperature, stretching speed and stretching ratio need to be controlled to ensure that the PET film achieves the ideal physical properties.
4. Coating treatment (optional)
Coating process: According to needs, PET film can be subjected to various coating treatments, such as adding waterproof, oil-proof, anti-static and other functions. The coating process is to pass the PET film through a coating machine, evenly apply the coating on the surface of the film, and then make it a PET film with specific properties through processes such as drying and curing. In this process, parameters such as coating thickness, coating speed and drying temperature need to be controlled to ensure the surface quality and functional performance of the PET film.
5. Heat shrinkage treatment
Thermal shrinkage principle: The heat shrinkable PET film remains stable at room temperature, but shrinks when heated above the glass transition temperature. This shrinkage is unidirectional, and usually requires more than 50% heat shrinkage in one direction.
Modification treatment: In order to obtain a PET film with a high heat shrinkage rate, it is usually necessary to copolymerize and modify ordinary PET. The maximum heat shrinkage rate of the copolymerized PET film can be as high as 70% or more.
Heat shrinking equipment: During the heat shrinking process, hot air heating equipment or infrared heating equipment is needed to heat the PET film to reach the temperature required for shrinkage and shrinkage occurs.
6. Quality control and inspection
Quality inspection: After each production link, the PET film needs to be inspected for quality, including appearance inspection, size measurement, physical property testing, etc., to ensure that the product quality meets the standard requirements.
Parameter adjustment: According to the test results, timely adjust the production parameters and process conditions to optimize product quality and production efficiency.
In summary, the production process of PET shrink film is a multi-process, multi-parameter controlled process. By strictly controlling the process parameters and quality inspection standards of each link, high-quality and high-performance PET shrink film products can be produced.
