The production steps of woven silicone tubing generally include natural rubber treatment, formulation according to usage requirements, mixing with a rubber mixing machine, parking (about 24 hours), recycling, semi-finished product production, vulcanization, edge cutting, and inspection. But refining will encounter this problem, which is the structuring of silicone gel. Next, let's analyze the reasons and control methods for the structural design of silicone tubes.

Structuring refers to the phenomenon where silica reinforced silicone rubber becomes harder and less malleable during storage, gradually losing its processability. This phenomenon is known as the "structuring" effect. Structured silicone rubber compound needs to be re mixed or heat-treated to eliminate this phenomenon, but the process cost will increase.

The reason for the occurrence of structured phenomena: One theory suggests that the active silanol groups on the surface of silica particles condense with the silanol groups at the end of the raw rubber molecules at room temperature, leading to hardening and reduced plasticity of the rubber material; Another explanation is that the Si-OH groups on the surface of silica react with the Si-O bonds or terminal Si-OH groups of rubber molecules to form hydrogen bonds, or even chemical bonds, transforming linear polydimethylsiloxane into a semi elastic solid structure with pseudo crosslinking or micro crosslinking. As a result, rubber becomes harder and its plasticity is greatly reduced.

Generally speaking, there are two control methods in the production of woven silicone hoses:

One is to add "structural control agents", silicone oil or silane with active groups, silicone resin, etc., which is the most commonly used method in production. For example, adding a certain amount of hydroxyl silicone oil, silazane, etc. can have a good structural control effect; The mechanism is that substances such as silicone oil with active functional groups undergo condensation reactions with the active hydroxyl groups on the surface of white carbon black, thereby preventing the interaction between white carbon black and raw rubber.

The second is the surface treatment of white carbon black, such as silane coupling agents, hexamethyldisilazane, etc., which can also prevent the structure of silica gel compounds. The mechanism is that coupling agents or silazanes have already coated the surface of white carbon black (reacting or hydrogen bonding), shielding the active groups on the surface of white carbon black, thereby preventing the interaction between white carbon black and raw rubber.
At present, hydroxyl silicone oil is commonly used, with a hydroxyl content of about 8% and a viscosity of about 20. The process is to powder and leave it for about 8 hours, followed by high-temperature treatment, so that the silicone oil can more thoroughly treat the hydroxyl groups on the surface of silica. If the customer uses it and there is not much demand, it is still difficult to control in actual production.

In addition, if the woven silicone tube needs to be surface treated with white carbon black, structural control agents and hydroxyl silicone oil need to be added, which should have a certain impact on its performance. Because structuring is a slow process of forming hydrogen bonds, the key lies in how to control the formation of hydrogen bonds. White carbon black treatment is a good method, but the cost is too high. The current common method is to use hydroxyl silicone oil, but additives alone are not enough, process control is required during the production process.