what are the chemical performance requirements for oval printing machine silicone materials?

When the automatic oval printing machine uses silicone ink for printing, what are the chemical performance requirements for silicone materials?
1. Ink corrosion resistance
Key indicators:
After soaking in ink for 24 hours, the volume change rate is ≤5%, and the hardness change is ≤±5A.
No discoloration, swelling or embrittlement (especially for solvent-based silicone ink).
Applicable ink types:
Solvent-based ink: It is necessary to select silicone that is resistant to aromatic hydrocarbons and ketone solvents (such as methyl vinyl silicone rubber VMQ).
UV curing ink: UV aging-resistant silicone is preferred (such as adding hindered amine light stabilizers).
2. Thermal stability
Applicable temperature range:
Room temperature vulcanized (RTV) silicone: -50℃~200℃.
High temperature vulcanized (HTV) silicone: -60℃~300℃ (suitable for high temperature curing ink process).
Test method: Thermogravimetric analysis (TGA) shows that the weight loss is less than 1% at 200℃.
3. Compatibility with ink
Requirement: No silicone oil or small molecule additives are precipitated on the surface of the silicone to avoid contamination of the ink and poor curing.
Verification method:
Drop a small amount of ink on the surface of the silicone before printing, and observe whether there is shrinkage or delamination after standing for 2 hours.
Long-term test: After continuous printing for 5,000 times, check whether the ink transfer amount is stable (fluctuation <±3%).