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The vulcanization mechanism of silicone tube after adding vulcanizing agent

The physical reaction of the silicone tube can be roughly distinguished by the naked eye, while the chemical mechanism cannot be observed, but it is determined that the final direction of the silicone tube is mainly divided into three vulcanization chemical mechanisms: organic peroxide-induced mechanism, condensation reaction mechanism , Addition reaction mechanism, the latter two are the main vulcanization mechanisms in the extrusion market now, the former has some obvious defects, mainly in the molding and calendering process. The core of all silicone vulcanization mechanisms is determined by the cross-linking point, so the silicone tube is not as simple as we imagined before it is formed, and it is more complicated in terms of the chemical and physical reaction mechanism.
  1. The chemical reaction mechanism of double di-tetrasulfurized silicone tube is the triggering mechanism of organic peroxide. In a popular way, silicone rubber guides the vulcanization crosslinking factor through the intervention of a third party. This is the earliest research on the vulcanization mechanism of silicone rubber. Products such as silicone tubes produced by this vulcanization mechanism will have a slight odor and burnt objects will be "black" and "brittle". The chemical principle is that the third-party intervening factor in peroxide vulcanization will guide the silica gel crosslinking factor to follow the free radical reaction mechanism. Free radicals are a kind of high molecular organic matter decomposed by organic peroxides in the process of heating and rolling, and in the process of guiding, the cross-linking factors will undergo fission and then repolymerize or be understood as phagocytosis until cross-linking Only when the connection point becomes larger can it be considered successful, and the physical reaction at this time should be that the silicone tube becomes elastic and not easy to tear because the chemical reaction mechanism in the silicone tube has been formed, and the cross-linking factors are precisely arranged together. Correlation Therefore, silicone tubes generally cannot be torn apart by brute force, and the whole body is undoubtedly struggling with thousands of cross-linking factors at the same time when pulling.
  2. The addition reaction type vulcanization mechanism is currently the most widely used one. It is mainly formed by mixing catalysts such as platinum vulcanizing agents. The main representative products are platinum vulcanized silicone tubes , platinum vulcanized silicone products, etc. The products use addition The reactive vulcanization mechanism does not produce side effects, and has the characteristics of non-toxic and tasteless, low scrap rate, and convenient control of cross-linking density. It is mostly used in some mid-to-high-end market fields. The cost of intervening materials added is also higher, mainly silicon in silica gel. Oxane and Si-H bond (a molecule in silica gel can be checked by Baidu) undergoes an addition reaction under the influence of a third-party intervening material (platinum vulcanizing agent), so that the original siloxane and Si-H bond in silica gel and Platinum vulcanizing agents form a more perfect high-level Si-H bond during the process of breaking and recombining each other, and some siloxanes will undergo fission during the catalytic process and form a grid with other siloxanes under the influence of crosslinking factors This is also the reason why the addition reaction type grid structure factor is not as dense as the organic peroxide grid structure, but the performance of the two is the same after being converted into a product. One is the deeply optimized grid structure. The lattice structure and the high-density lattice structure each have their advantages and disadvantages.
  3. The condensation reaction type vulcanization mechanism may be less heard and has the same effect as the addition reaction type. Platinum vulcanizing agents can also be used for catalysis, but the requirements are more stringent. The environment, temperature, humidity, vulcanization system, and product use , and the product structure are involved. The condensation reaction type is more complicated, mainly due to the vulcanizing agent and the fission of many factors in the process of compacting, mainly using siloxane as the crosslinking agent in a constant temperature environment. The fission factors form a cross-linking reaction, and in this reaction mechanism, a variety of chemical factors will be condensed and need to be stripped. The main products are platinum special silicone tubes or special silicone products, which can also be used in ordinary silicone tubes.
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