Key Considerations When Choosing Silicone Thinner
Match the Ink Type to Avoid Reactions or Curing Abnormalities
Silicone inks can be categorized as addition-type and condensation-type based on their curing mechanism, and their compatibility with Thinner differ significantly:
Addition-type silicone inks rely on platinum catalysts for crosslinking. Thinner must avoid containing "inhibiting ingredients" (such as compounds containing sulfur, nitrogen, or phosphorus, or heavy metal ions), otherwise they will result in incomplete curing and a sticky surface.
Condensation-type silicone inks cure through the reaction of hydroxyl groups with a curing agent (such as a crosslinker). Thinner must avoid containing large amounts of water or acidic/alkaline substances to prevent disruption of the crosslinking reaction.
Controlling the Evaporation Rate to Adapt to the Printing Process
The diluent's evaporation rate must be matched to the printing speed and ambient temperature and humidity:
If evaporation is too fast, the ink will easily dry on the screen, resulting in screen blocking and image incompleteness.
If evaporation is too slow, the ink will experience excessive leveling (blurred image) after printing, requiring prolonged drying time, and even affecting subsequent curing.
For example, fast-drying Thinner are recommended for high-temperature, high-speed printing, while slow-drying Thinner are recommended for low-temperature or fine-detailed printing. Do not affect ink performance and substrate adhesion.
The diluent must be fully compatible with the silicone matrix, pigment, and other components of the ink to avoid delamination, precipitation, or particle release.
Avoid using Thinner that may corrode the substrate (for example, when printing on surfaces like plastic and leather, test to see if the diluent causes swelling or discoloration).
Excessive addition can reduce the ink's post-curing hardness, elasticity, and adhesion. Generally, the addition amount should not exceed 10%-20% of the total ink volume (refer to the ink manufacturer's recommendations).
Safety and Environmental Protection
Prefer low-toxicity and low-volatile organic compound (VOC) Thinner to minimize operator health risks (for example, avoid highly toxic solvents such as benzene and halogenated hydrocarbons).
Comply with local environmental regulations (such as EU REACH and domestic VOC limit standards). Ensure that the diluent residual content meets the standards, especially when screen printing on food contact products or children's products.
