Impact of platinum catalyst addition ratio on silicone performance
| Addition Ratio Situation | Change in Cross - Linking Density | Specific Impacts on Mechanical Properties |
|---|---|---|
| Insufficient Ratio | Low cross - linking density (few connection nodes in molecular chains) | 1. Low hardness (e.g., designed Shore A 50, but the actual hardness... 2. Poor tensile strength/tear strength (easily pulled and broken... 3. Poor elastic recovery (unable to rebound after deformation, e.g., silicone keys sink after being pressed... 4. Large permanent compression deformation (unable to recover after long - term compression, leading to seal failure... |
| Appropriate Ratio | Moderate cross - linking density (in line with formula design) | 1. Hardness precisely meets the standard (error within ±2 Shore A) 2. Tensile strength (usually 5 - 10 MPa) and tear strength (usually... kN/m) meet the application requirements 3. High elastic recovery rate (rebound rate > 95% when deformation < 50%) 4. Small permanent compression deformation (e.g., deformation rate < 10% after 150°C×22h test... |
| Excessive Ratio | Excessively high cross - linking density (too many and too dense connection nodes in molecular chains) | 1. High hardness (e.g., designed Shore A 50, but the actual hardness... 2. Increased brittleness and decreased elasticity (prone to "brittle fracture" during stretching... 3. Decreased tear strength instead (excessively dense cross - linking causes molecular... and direct fracture under force) 4. Poor low - temperature toughness (prone to hardening and cracking at low temperatures... |