In order to meet the needs of different customers for the temperature resistance of silicone, OrientFlex conducts research on the temperature resistance of silicone hose and the improvement of product performance.
Heat resistant silicone hose is mainly dependent on the raw material. If the raw material is not good, even a good heat resistance system will not help. Generally the heat resistance of recycled rubber is generally not very good, so some heat resistant antioxidants can be added during production. For example, TT and asbestos powder.
Adding asbestos powder and TT to the rubber can improve the heat resistance of the rubber and increase the high temperature and aging resistance of the product, but there are differences between different varieties of recycled rubber, so it is not enough to improve TT, add asbestos powder and change to low sulfur! First of all, we have to distinguish which type of rubber, do products after the physical product requirements, and then decide to improve the heat resistance of the method.
Steps to improve the high temperature resistance of silicone hose
1. Add silica
Silica is a commonly used reinforcing agent for silicone rubber, silica is mainly through its surface of the silicon by group or with the main chain of silicone rubber on the Si-O bond or end groups on the by group combination, so that the thermal movement of the main chain of silicone oxygen and O2 in the silicone rubber network is not easy to diffuse, when the silicone rubber in high temperature conditions when the thermal oxidative decomposition of free radicals and silica on the silicon by group reaction and be consumed, to improve the heat resistance stability. The thermal stability of silicone rubber is improved by reducing the number of warp groups on the silica surface.
The study analyzed the effect of silica warp groups on silica on the performance of silicone rubber, and found that by using silane coupling agent to modify the treatment of silica, the surface warp group content was reduced and the heat resistance of silicone rubber was improved.
2、Adding silicone resin
Both silicone resin and silicone rubber are polymers with silicone oxygen bond as the main chain, and the side groups are connected with methyl, phenyl. With a highly cross-linked network structure, due to its structural characteristics, giving silicone resin itself excellent high temperature resistance, often as a reinforcing agent is added to silicone rubber to hinder the main chain of silicone rubber unbuckling degradation reaction, to improve the high temperature resistance and mechanical properties of silicone rubber.
How to improve the thermal aging property of silicone rubber
It is found that when silicone resin is added to high temperature vulcanized silicone rubber, the silicone resin can significantly improve the thermal stability of silicone rubber due to the highly cross-linked mesh structure of silicone resin, which hinders the ring degradation reaction of silicone rubber molecular chains. When adding phenyl silicone resin, it can improve the heat aging performance of silicone rubber.
3、Adding metal oxide
It is found that adding metal oxides to the silicone rubber matrix rubber to hinder the oxidative degradation of silicone rubber side groups and cross-linking reaction. Due to chain growth and chain termination reaction triggered by the cross-linking of silicone rubber system, hardening, the mechanism of action is exactly the same, silicone rubber oxidation process has free radical generation, metal ions capture free radical process is reduced, and then prevent the chain growth reaction, improve the high temperature resistance of silicone rubber. In order to solve the problem of metal oxide dispersion in silicone rubber, it is usually modified with silane coupling agents, etc., to improve the dispersion of metal oxide in the silicone rubber matrix.
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