The Shrinkage Principle Of Cold Shrink Tube
In the previous article, we have introduced the principle of heat shrink tubing, so today we will talk about the principle of Cold Shrink Cable Accessories. At present, cold shrink tubing can be mainly divided into silicone cold shrink tubing and EPDM cold shrink tubing according to different raw materials. The former is made of silicone rubber and the latter is made of EPDM rubber. Although the raw materials of the two cold shrink tubings are different, their shrinking principles are the same, so let's take silicone cold shrink tubing as an example.
After mixing and vulcanization of silicone rubber raw rubber, the original silicone macromolecular structure will undergo a cross-linking reaction to form a network structure, thereby increasing the strength and elasticity of the connection between silicone molecules. Elasticity is achieved through the transformation of intermolecular configuration and the change of intermolecular length. Raw rubber that has not been vulcanized is easy to tear and can be gently torn by hand, just like tearing dough, but after vulcanization, silicone becomes elastic, like rubber. That is to say, after the vulcanization process, the silicone tube we extrude can be deformed under the action of external force. At the same time, because the molecules are still in an activated state at room temperature, after the external force is removed, the resilience between the molecules, that is, the molecules shrink to a certain extent due to the internal stress caused by deformation, which is the shrinkage principle of the cold shrink tube.
It should be noted that this principle is a bit like heat shrink tube, but the difference between cold shrink tube and heat shrink tube is mainly that the molecules of heat shrink tube are frozen at room temperature and need high temperature activation, so they need to be heated, so they are called heat shrink, while cold shrink tube does not need to be heated, so it is called cold shrink.
In actual manufacturing, after the silicone tube is expanded, a support tube that can be easily extracted is added to make a cold shrink tube. In fact, this is a pre-expansion process. The support strip can be removed during installation, which is very convenient and easy to use.
Whether it is silicone rubber cold shrink tube or EPDM rubber cold shrink tube, they have excellent weather resistance, acid and alkali resistance, and achieve the effect of breathing seal. They are ideal sealing products for communication cables, coaxial cables, and medium and low voltage power cables.
