How To Adjust The Hardness Of Silicone

How to adjust the hardness of silicone
1. Material mixing method
High and low hardness silicone mixing: The hardness of silicone can be adjusted by mixing high and low hardness silicone raw materials in a certain proportion. For example, after mixing 50 hardness silicone with 30 hardness silicone in a 1:1 ratio, the hardness of silicone may drop to about 40 Shore A. This method has relatively little effect on the physical properties of silicone, but attention should be paid to the compatibility and mixing uniformity of the two silicones.
Precautions: When mixing, make sure that the two silicones are of the same type (such as addition type or condensation type), otherwise it may not cure or degrade in performance.
2. Additive method
Silicone oil addition: Use silicone oil (especially silicone oil with high viscosity) to reduce the hardness of silicone. The amount of silicone oil added should be controlled within a certain range (generally not more than 5%). Too much silicone oil will destroy the molecular weight of silicone and affect its physical properties (such as tear resistance and tensile strength). After adding an appropriate amount of silicone oil, the hardness of silicone will decrease accordingly, and the viscosity will also become thinner.
Other additives: If you need to increase the hardness of silicone, you can consider adding inorganic or organic fillers, such as silica (fumed silica), carbon black, ceramic powder, etc. These fillers can increase the hardness and wear resistance of silicone, but will also have a certain impact on its elasticity and other properties.
3. Process control method
Heat aging: By heating and aging silicone products, you can extend their curing time and increase their hardness. This method requires strict control of conditions such as temperature and time to ensure the stability of the performance of silicone.
Curing agent adjustment: For condensation silicone, the curing speed and hardness of silicone can be affected by adjusting the amount or type of curing agent. However, this method has a limited range of adjustment for hardness and requires careful operation to avoid performance degradation.
4. Customized production
When ordering liquid silicone, you can explain your specific needs to the supplier, including the required hardness, color, operation time and other characteristics. Suppliers can directly adjust the hardness of silicone when producing raw materials to meet customer needs.