Heat shrink tubing is a versatile product that is used frequently by a broad range of professionals in different industries. The tubing can be applied to cabling, components and other types of substrates for any number of reasons.
Incredibly easy to use, heat shrink tubing can serve many different purposes, including electrical insulation, repairs, protection, reinforcement, identification and more.
It is available in a number of different materials, each with different strengths and properties for particular applications.
In this guide, we look at some of the most important properties of heat shrink tubing as well as some of the materials that can be used for different applications. First though, we will cover some of basics about heat shrink material.
Heat shrink material basics
Heat shrink tubing is manufactured in a multitude of varieties and chemical make ups. The exact composition of each type is heavily dependent on the product’s intended application.
Although most heat shrink tubes share some common characteristics, there is a high degree of difference that separates some products from others. Some heat shrink tubing materials, for example, will be almost microscopically thin and rigid – suitable for specialist purposes like wrapping batteries or labelling. Others, meanwhile, will have very heavy walls and a special additive to help protect electrical components in harsh environments.
All heat shrink tubes have a shrinking ratio, which indicates the difference between it’s expanded state and recovery state. A higher shrink ratio is necessary for certain applications as it makes the tube easier to slip into position, particularly if there are any large components that need to be traversed.
Some heat shrink tubes also come with a layer of thermoplastic adhesive on the inside surface. This helps provide a better seal and more adhesion in certain applications.
Heat shrink material properties
Here are some of the most important properties for heat shrink tubing materials and some potential applications.
Flexibility– Flexibility refers to a material’s ability to bend without breaking. Heat shrink tubing generally needs to be bendable to provide a close,protective seal around the substrate, particularly when applied to cables that will move frequently. Some heat shrink materials are more flexible than others, particularly when they are used at extreme temperatures.
Elastomeric– Elastomeric materials have rubber-like properties, meaning that they can regain their original shape after a load has been removed. All heat shrink tubing materials are elastomeric, meaning that they can be moved into position more easily.
Heatresistance– As well as a shrinking temperature that needs to be reached in order to make the product shrink, heat shrink tubing products also have safe operating temperatures that are determined by the material’s heat resistance. Only some heat shrink products can be used at extreme temperatures.
Abrasion resistance– Abrasion resistance refers to a material’s ability to resist being worn away by rubbing or friction. Abrasion resistance is important for some heat shrink applications, particularly when it is used for protection, reinforcement or in a particularly sensitive locations such as in cable harnessing, transport and certain aerospace and military applications.
Chemical resistance – Chemical resistance is the ability of a material to resist degradation from chemicals. Heat shrink material that with strong chemically resistant properties is less likely to corrode in the presence of common chemicals such as diesel and petrol. Chemically resistant tubing is useful in a variety of situations, including in automotive, aerospace and military applications.
UV resistance– UV (ultraviolet) resistance is the ability of a material to withstand degradation that can be cause by exposure to UV light. Some materials can lose performance if they are exposed to UV light for long periods, so heat shrink tubing that is exposed to a significant amount of sunlight should be UV resistant, particularly those in transport and military applications.
Most popular heat shrink materials
Here are some of the most common materials used in heat shrink tubing.
Polyolefin heat shrink tubing
Polyolefin is the most widely used heat shrink tubing material. It is a synthetic polymer with a strong resistance to high temperatures and chemical contamination, making it suitable for a range of applications.
PVC heat shrink tubing
Polyvinyl chloride or PVC is another popular heat shrink material. The material offers good protection and has a smooth surface. Different types of PVC material can be used for battery casing and large-scale identification projects.
PTFE heat shrink tubing
Polytetrafluoroethylene or PTFE is a synthetic compound that has a high resistance to chemicals. It is also relatively frictionless, meaning that liquids such as chemicals will slide off the surface of PTFE easily. PTFE is also known by the brand name Teflon and is recognised as a high-performance heat shrink tube suitable for a broad range of applications.
FEP heat shrink tubing
Fluorinated ethylene propylene (FEP) tubing is highly resistant to chemical spillage and shrinks at a low temperature compared to PTFE. It is also highly flexible, has good optical clarity and high lubricity relative to some other types of heat shrink tubing.
PVDF heat shrink tubing
Polyvinylidene fluoride or PVDF heat shrink tubing is flame resistant and good against fuels and other chemicals. PVDF tubing is semi-rigid and particularly useful in hostile environments where protection is at a premium, such as in electronic, automotive and certain military applications.
Silicone heat shrink tubing
Silicone heat shrink tubing is particularly useful for its flexibility and resilience at very high or very low temperatures. It is used for insulating heating elements that can get very warm and bundling fibre optic cables. It is also widely used in medical environments as it can be easily sterilised without compromising on performance.
Viton heat shrink tubing
Viton heat shrink tubing is made using another high-performance material. It is made from fluoroelastomer – a type of synthetic rubber. It has very god chemical and temperature resistance and remains flexible at low temperatures. It is used widely as a seal against oils, fuels and lubricants in many different environments.