Heat Shrink, also acknowledged as heat shrink tubing, is a plastic tube, which is easily shrinkable in nature. This plastic tube has multiple usages in the field of electric engineering. It is used to repair and correct insulation on wires and bundle them together. Also, it is used for corrosion resistance and to insulate wires, providing environmental safety for wrecked and solid wire conductors, joints, terminals and connections that are utilized in electrical engineering. Additionally, heat shrink is used to make cable entry seals. Usually, it is made up of nylon or polyolefin, which shrinks gradually to ½ or 1/6 of its diameter at the time of heating.

These plastic tubes are manufactured in a wide range of varieties and chemical coverings, having an accurate composition of each type. There are different types of heat shrink tubing, depending upon color and their manufacturing. Colorful heat shrink tubes are used for color-coding of wires and connections. In early days of the 20^th century, these types of tubes are used for PC modding, so as to clean-up the internal part of the computers as well as to provide a pleasing look. As a result of this, companies also started manufacturing these tubes in luminous and UV reactive types. Apart from insulation, these tubes are used on unsoldered cable joints. Moreover, the end-caps of the tube, which is closed from one side, are used to insulate the open and uncovered cut ends of the insulated wires.

Uses of Heat Shrink

Different methods are used to shrink the tube, and among them, the most expedient but less consistent one is soldering iron or the heat coming from a lighter. These methods of shrinking the tube are generally not recommended, because there are high chances of uncontrolled heat, which may cause uneven shrinkage, insulation failure, and physical harm. This plastic tube provides solid electrical insulation, and security against dust, solvents, and other external materials. It is also used as a mechanical strain relief. Besides, in the early 70s, it is used as covering of fiberglass helical antennas that are excessively used for 27MHz CB Radio. Several of these types of antennas and other cable accessories have been coated using these shrink tubes.

Materials Used

Depending on the usage and applications, these tubes are made of different materials. Some examples are stated here with:

1. PTFE: These tubes are available in a diverse operating temperature range and with high resistance to punctures and chemicals. Also, they have a low coefficient of friction.
2. Polyvinylidene Fluoride (PVDF): These tubes are required for high-temperature areas.
3. Silicon Rubber: These tubes are highly flexible and have high resistance to abrasion. Their operating temperature ranges from -50 to 200 Degree Celsius.
4. Fluorinated ethylene propylene(FEP): These tubes are low-cost alternatives to PTFE tubes, and are nonreactive to most of the solvents and chemicals. These are versatile electric insulators and are resistant to heat, cold and UV rays.
5. Elastomeric: These tubes are extremely flexible in nature, even at low temperatures. Their operating temperature range is -75 to 150 Degree Celsius. Also, these tubes are resistant to various chemicals and abrasion.