In the vast field of silicone materials, addition type and condensation type silicone exhibit completely different performance characteristics and application directions due to differences in crosslinking mechanisms. The core reaction of addition molded silicone is hydrosilylation, which relies on platinum catalyst to catalyze the specific binding of Si-H and C=C double bonds between hydrogen containing silicone oil and vinyl silicone oil, forming a stable Si-C bond network. This process can be completed at room temperature or heating conditions, with fast curing speed and low shrinkage rate, endowing the material with excellent dimensional stability and transparency. It is commonly used in precision demanding scenarios such as electronic component packaging and medical catheters.

Condensed silica gel achieves cross-linking through condensation reaction, and triggers dehydration or dealcoholization reaction between silanol and silanol groups using catalysts such as organotin, forming Si-O-Si bond network. This process is often accompanied by the release of small molecule by-products such as ethanol or water, with a long curing time and susceptibility to environmental humidity. However, it has lower cost and strong adhesion to the substrate, making it more suitable for large-scale construction scenarios such as building sealing and waterproof coatings.

In terms of performance differences, addition molded silicone has better environmental friendliness and outstanding high-temperature resistance due to the absence of small molecule by-products. It has a high flash point and high thermal decomposition temperature, making it suitable for use in high-temperature environments; Although condensed silica gel has good weather resistance, its performance may deteriorate due to the volatilization of by-products at high temperatures over a long period of time. In addition, the crosslinking density of addition molded silicone can be precisely controlled by adjusting the ratio of silicone hydrogen to vinyl, achieving a wide range of hardness from soft elastomers to hard materials; Condensed silica gel has a relatively narrow range of hardness adjustment due to reaction mechanism limitations, but its wear resistance and tear resistance can be improved through filler modification.

Both need to consider the process requirements comprehensively in their application selection: additive silicone has become the preferred choice for precision molds and optical devices due to its fast curing, low shrinkage, and high transparency; Condensed silicone occupies an important position in the fields of building and automotive sealing due to its low cost, strong adhesion, and easy construction characteristics. This differentiated pathway based on cross-linking chemistry not only reflects the multifunctionality of silicone materials, but also reflects the precise balance between performance and cost in industrial applications.

Regarding liquid silicone rubber, please refer to our website for details: IOTA Liquid Silicone Rubber