Key factors affecting adhesion of silicone

Key factors affecting adhesion of silicone
1. Silicone formula characteristics
Curing type: Addition silicone (platinum catalysis) cures more completely than condensation silicone (tin catalysis), has a high crosslinking density, and has better adhesion and weather resistance.
Additives: Silicone containing silane coupling agents (such as KH-550, KH-560) can react with the hydroxyl groups on the fiber surface to form chemical bonds (such as Si-O-C bonds), significantly improving adhesion.
Hardness and elasticity: Low hardness (such as 20-40A) silicone is more suitable for elastic fabrics, which can reduce stress concentration during stretching and avoid degumming; high hardness silicone (>50A) is suitable for rigid fabrics, but lacks flexibility.
2. Fabric pretreatment process
Cleaning treatment: Remove oil stains, release agents or lubricants (such as textile auxiliaries residues) on the fabric surface, usually wipe with alcohol or plasma cleaning.
Surface roughening: Increase the surface contact area and strengthen mechanical anchoring through corona treatment (polyester fiber), sandblasting (leather) or primer roughening agent.
Primer application: For inert fabrics (such as polyester and spandex), apply a layer of adhesion promoter (such as primer containing acrylate or silane) before printing, and then print silicone after drying, which can increase the adhesion by 30%-50%.
3. Printing and curing process
Printing thickness: Too thick glue layer (>0.5mm) is prone to cracking due to internal stress. It is recommended to control it within 0.1-0.3mm and achieve it through multiple thin printing stacking.
Curing conditions: Addition type silicone needs to be cured at 120-180℃ for 5-15 minutes to ensure complete cross-linking; when condensation type silicone is cured at room temperature, it is necessary to avoid insufficient moisture to cause incomplete curing and affect adhesion.