The production process of the PET release film series usually includes the following main steps:
Raw material preparation
PET base film selection: According to the performance requirements of the product, select a PET film of appropriate thickness, optical properties and physical properties as the base film. The common thickness of PET base films ranges from 12μm to 100μm.
Release agent selection: The release agent is a key factor determining the release performance of PET release films. Commonly used release agents include silicone release agents, fluorine-based release agents, etc. According to different release force requirements and application scenarios, select the corresponding release agent and formula.
Surface treatment
Corona treatment: Through corona discharge, polar groups are generated on the surface of the PET substrate film, increasing the surface energy and enhancing the adhesion between the release agent and the substrate film. The intensity and duration of corona treatment need to be adjusted according to the material and thickness of the PET base film.
Primer treatment: Apply a layer of primer on the surface of the PET base film after corona treatment to further enhance the adhesion between the release agent and the base film. Primer is usually a polymer solution containing special functional groups, which can undergo chemical reactions with PET base films and release agents to form strong chemical bonds.
Release agent coating
Coating method selection: Common coating methods include troweling, roller coating, and spraying, etc. Scraping coating is suitable for situations where high coating accuracy is required and the viscosity of the release agent is relatively large. Roller coating has the advantages of fast coating speed and good uniformity. Spraying is suitable for occasions where the coating amount is required to be low and rapid drying is needed.
Coating parameter control: Precisely control the coating amount, coating speed and drying conditions of the release agent. The coating amount is generally adjusted between several grams and tens of grams per square meter according to the release force requirements. The coating speed is usually between 10 meters and 100 meters per minute. The drying temperature and time are optimized according to the type and formula of the release agent. Generally, the drying temperature is between 80℃ and 150℃, and the drying time is between 1 minute and 10 minutes.
Curing treatment
Curing method: For silicone release agents, high-temperature curing or ultraviolet curing methods are usually adopted. High-temperature curing involves heating the PET film coated with a release agent to a certain temperature in an oven, causing the organosilicon polymer in the release agent to undergo a cross-linking reaction and form a three-dimensional network structure, thereby achieving excellent release performance. Ultraviolet curing is a process that uses ultraviolet light to irradiate the photoinitiator in the release agent to generate free radicals, triggering a polymerization reaction to achieve curing.
Curing parameter control: Curing temperature, time or ultraviolet irradiation intensity and time are the key parameters of curing treatment. The high-temperature curing temperature is generally between 150℃ and 250℃, and the curing time varies from several minutes to tens of minutes. During ultraviolet curing, the irradiation intensity is usually between tens of milliwatts per square centimeter and hundreds of milliwatts per square centimeter, and the irradiation time is between several seconds and tens of seconds.
Slitting and packaging
Slitting: According to the customer's requirements, the cured PET release film is slitted into different widths and lengths. During the slitting process, it is necessary to ensure the cutting accuracy and avoid problems such as edge burrs and dimensional deviations.
Packaging: The slit PET release film should be wrapped with plastic film or paper packaging materials to prevent contamination, scratches or moisture during transportation and storage. For some high-end products, vacuum packaging or nitrogen-filled packaging and other methods may also be adopted to further enhance the quality stability of the products.
Throughout the entire production process, strict quality inspections need to be carried out on each procedure, including the testing of release force, transparency, tensile strength, thickness uniformity and other indicators, to ensure that the products meet relevant standards and customer requirements.
