How to choose the right liquid silicone mixing ratio based on the mechanical performance requirements of the product?
1. Mechanical performance requirements
Hardness: Does the product need to be soft (such as baby pacifiers, 0-30 Shore A), medium-hard (such as sealing rings, 40-60 Shore A) or hard (such as industrial gaskets, 70-80 Shore A)?
1:1 addition type silicone: The hardness range is the widest (0-80 Shore A), and the soft type (such as 0 Shore A) has better elasticity and resilience.
10:1 or 100:2: Condensation type is mostly low hardness (10-50 Shore A), and addition type 10:1 can reach medium-high hardness, but the brittleness at high hardness is slightly higher than 1:1.
Strength/aging resistance: Does the product need to be repeatedly stretched (such as silicone tubes), long-term high temperature resistance (such as oven accessories) or anti-aging (such as outdoor products)?
Priority 1:1 addition type: high tensile strength (usually 3-8MPa), high and low temperature resistance (-60℃~200℃+), UV resistance and oxidation resistance, suitable for long-term use.
10:1 Second: Industrial-grade scenarios (such as ordinary seals) can be met, but aging resistance is weaker than 1:1.
100:2 Worst: Condensation type is prone to become brittle due to small molecule residues after curing, and is only suitable for short-term use (such as disposable molds).