To solve the problem of pressing down fine fibers and avoiding pinholes or fiber protrusions when screen-printing silicone on cotton fabric, the core approach is to optimize the silicone ink formulation to enhance its hiding power and spreadability.
Ordinary silicone inks lack sufficient fluidity and hiding power, making it difficult to cover the fabric fibers. Targeted adjustments are required as follows:
Select high-solid-content and high-hiding-power silicone ink
Prioritize addition-cure silicone ink (compared with condensation-cure silicone ink, it forms a denser film and exhibits stronger adhesion after curing). The solid content is recommended to be ≥ 90%, which reduces fiber exposure caused by ink shrinkage after solvent evaporation.
If the hiding power is insufficient, add silicone-specific high-transparency hiding powder (e.g., nano-silica, fumed silica) at a controlled dosage of 3%–5%. Excessive addition should be avoided to prevent ink thickening and screen clogging.
Adjust ink viscosity and thixotropy
Control the viscosity at 15,000–25,000 mPa·s (at 25℃). Excessively high viscosity will prevent the ink from fully filling the fiber gaps; excessively low viscosity may cause ink bleeding and pinholes.
Add silicone-specific leveling agent at a ratio of 0.5%–1% to improve the spreadability of the ink on the cotton fabric surface, allowing the ink to wrap around the fine fibers.
Never dilute the ink with ordinary organic solvents. Only use silicone-specific thinner to avoid damaging the silicone curing system.
Anysil silicone ink AS9301 would be your best choice.
