Notes for Silicone Heat Transfer on Shoe Uppers
Confirm Material First & Select Corresponding Silicone Heat Transfer Film
For PU/synthetic leather uppers: Choose silicone heat transfer films containing PU-specific adhesion promoters (e.g., isocyanate-modified silicone). Avoid universal silicone films.
For mesh/polyester fiber uppers: Select silicone heat transfer films with low hardness (Shore A 30-40) and high elasticity, combined with "silane coupling agent pretreatment" (see Step 2 below).
For PVC/rubber uppers: Prioritize material replacement (e.g., switch to PU). If replacement is not feasible, use PVC-compatible special silicone heat transfer films (containing chlorinated olefin-modified components) or apply a silicone primer to the upper surface in advance.
Shoe Upper Pretreatment (Critical Step with Low Cost & Significant Effect)
Cleaning & Degreasing: Wipe the upper with anhydrous ethanol or isopropanol (avoid acetone, as it may corrode PU/PVC) to remove surface mold release agents, grease, and dust. Allow it to air-dry completely (ensure no residues remain).
Improve Surface Roughness:
For smooth PU/genuine leather: Lightly sand the surface with 400-600 grit fine sandpaper to enhance adhesion (avoid over-sanding to prevent material damage).
For mesh/fibers: Treat with a plasma processor (commonly used in factories) or spray a small amount of silane coupling agent (e.g., KH-550). Allow it to dry before transfer (the coupling agent acts as a "bridge" between silicone and fibers).
Moisture Removal: If the upper is moisture-absorbent (e.g., mesh), dry it in an oven at 60℃ for 10 minutes in advance to avoid air bubbles during heating, which may affect adhesion.