The process of Silicone release coating for double sides coated PE coated paper
Silicone release coating on double-sided PE (polyethylene) coated paper involves several specialized steps to ensure that both sides of the paper are properly coated with silicone. PE-coated paper is often used as a substrate due to its moisture resistance and smooth surface. Here’s a detailed look at the process:
1. Substrate Preparation
Paper Selection:
- Select high-quality PE-coated paper that can withstand the coating and curing processes. Ensure that the PE coating is uniform and well-adhered to the paper substrate.
Surface Treatment:
- Treat the PE-coated surface with corona or plasma treatment. This increases the surface energy of the polyethylene, improving the adhesion of the silicone release coating.
2. Coating Formulation
Silicone Release Coating:
Catalyst Selection:
- Choose the appropriate catalyst for the curing method (thermal or UV curing). This will ensure efficient and complete curing of the silicone coating.
3. Coating Application
Coating Method:
- Use a coating method such as gravure coating, Mayer rod coating, or reverse roll coating. For double-sided coating, the process can be done in a single pass with a double-sided coater or in two passes with the substrate flipped between coats.
First Side Coating:
- Apply the silicone release coating to the first side of the PE-coated paper. Control the coating thickness and uniformity to achieve consistent release properties.
4. Curing
Thermal Curing:
- For thermal curing, pass the coated paper through an oven where heat is applied to cure the silicone coating. The temperature and curing time depend on the specific silicone formulation.
UV Curing:
- For UV-curable silicone formulations, pass the coated paper under UV lamps to initiate and complete the curing process.
First Side Curing:
- Ensure the silicone coating on the first side is fully cured before proceeding to the second side to prevent contamination or adhesion issues.
5. Second Side Coating and Curing
Second Side Coating:
- Once the first side is cured, flip the paper and apply the silicone release coating to the second side using the same method.
Second Side Curing:
- Cure the silicone coating on the second side using either thermal or UV methods, ensuring the coating is fully cured.
6. Quality Control and Inspection
Coating Uniformity:
- Inspect both sides of the coated paper for uniformity, thickness, and any defects. Ensuring even coating and proper curing is crucial for maintaining consistent release properties.
Release Properties Testing:
- Test the release force of the silicone-coated paper to ensure it meets the desired specifications. This involves measuring the force required to peel off a standard adhesive from the coated surface.
7. Finishing and Slitting
Rewinding:
- Rewind the double-sided silicone-coated PE-coated paper into rolls for easier handling and further processing.
Slitting:
- Slit the rolls into desired widths as per customer specifications. This may involve precise cutting equipment to maintain edge quality and uniform roll dimensions.
8. Packaging and Distribution
Packaging:
- Package the finished rolls carefully to protect the silicone coating during transportation and storage. This often involves wrapping in protective materials and placing in sturdy containers.
Labeling and Shipment:
- Label each roll with relevant information such as coating specifications, lot number, and handling instructions before shipment to customers.
Conclusion
Silicone release coating for double-sided PE-coated paper involves meticulous preparation and processing steps to ensure both sides are evenly coated with silicone. This process includes substrate preparation with surface treatment, precise application of silicone coating, curing, and rigorous quality control. The choice between thermal and UV curing, as well as the specific coating methods, can vary depending on the application requirements and characteristics of the silicone formulation. Proper execution of each step ensures the final product meets the desired performance standards for various industrial applications.
