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Why Does Heat Shrink Tubing Shrink when Heated?

Have you ever seen a plastic tube that shrinks when heated? It has an elegant professional name called the heat shrinkable tube. Why does the heat shrinkable tube commonly used in life shrink when it is heated?


1. The the heat shrinkable tube in life


Heat shrinkable tube has the characteristics of softness, flame retardant, environmental protection, wear resistance and anticorrosion, and its application in life is becoming more and more extensive. A variety of heat shrink tubes are used in electronic and electrical manufacturing, sports equipment, communication industry, automobile and ship manufacturing, power cables and other aspects. The magic of the heat shrinkable tube is its shape memory function, which means the expanded product can shrink to the state before expansion after heating. This is due to its magical molecular structure after irradiation cross-linking.


2. The reason why the heat shrinkable tube shrinks when it is heated


Polyethylene is the main material of heat shrinkable tube products. It is an aggregate of linear molecular structures formed by the polymerization of ethylene monomers. The molecular formula of ethylene monomers is H2C=CH2. In the polymerization condition, the double bond of each ethylene monomer molecule is opened, and several molecules are polymerized into polyethylene with linear properties. Polyethylene is the most common plastic raw material. They do not have thermal shrinkage properties. After fully mixing with other fillers (color masterbatch, flame retardant, etc.), the master batch of heat shrinkable tube is made, and the master batch is extruded to become the initial semi-finished product of heat shrinkable tube. Then, the polyethylene tube at this time is irradiated and cross-linked, and the linear molecular structure is changed to a network molecular structure. The processed polyethylene tube already has a shape memory function, and the tube will only become soft and will not become a molten state when placed in the oven. Then expand it to form our finished heat shrinkable tube.


3. Why are heat shrinkable tubes more and more popular?


The heat shrinkable tube with shape memory performance can excellently protect the joints of wires and cables, optical cables, and metal pipe rods. It can be used as a special insulating material in aerospace, cutting-edge technology, and military technology sectors, and heat shrinkable tubes are more and more popular in all walks of life.


The heat-shrinkable material can not only be made into a radially shrinkable heat shrinkable tube, but also can be made into a plastic film that shrinks in both warp and weft directions, which can be used in packaging, protecting items, etc. Heat-shrinkable materials have a promising future thanks to their excellent performance. The heat shrinkable tube looks insignificant, but in fact its invention also embodies the crystallization of the wisdom of many people. The inventions in the field of electronics basically come out step by step.