Heat Shrink History

By: CableOrganizer®


Heat shrink plastic tubing is expanded, extruded plastic sleeving that is designed to contract when heated. It is commonly used to provide sealing, termination, identification, insulation and strain relief for cables. It has many uses in electrical, electronic, telecommunications, cable management and virtually all other industries. There are many variations to meet different needs: economical options for light, unexposed use; general purpose and high temperature versions for automotive, aerospace and military applications; and adhesive lined heat tubing for tight seals that keep out dust and moisture.

The most common method for contracting heat shrink is the heat gun. Heat guns range from moderate heat fixed temperature versions for general use, to variable temperature models with digital readouts. The heat shrink oven is a costlier and less portable option but is more energy efficient.

In addition to heat shrink tubing and heat gun/hot air tools, this section also features heat shrink connectors you need to take your heat shrink project from start to finish, including heat shrink labels and high temperature specialized heat tubing.

Heat Shrink Tubing: How It Was Invented, and Why We Use It

Sure, heat shrink tubing is cool and fun to use, but have you ever wondered how it came about, what makes it work, or how many uses it actually has? If so, CableOrganizer® can help — just have a quick read through our FAQs and you'll be an expert on heat shrink tubing in no time.


Heat shrink tubing was originally developed by Raychem Corporation in the late 1950s, when Raychem's chemical engineer founder Paul Cook, along with inventor Judson Douglas Wetmore, made use of radiation chemistry (from which his company's name is derived) to develop the two main products that Raychem was originally known for: lightweight aircraft cable, and heat-shrinkable tubing. While Raychem pioneered heat shrink polymers, today they're produced by many different manufacturers including 3M®, NTE®, Techflex® and Zippertubing®.


Heat shrink tubing can be made of any one of a range of thermoplastics, including polyolefin, polyvinyl chloride (PVC), Viton® (for high-temp and corrosive environments), Neoprene® (polytetrafluoroethylene (PTFE)), fluorinated ethylene propylene (FEP) and Kynar®. In addition to these polymers, some types of special-application heat shrink can also include an adhesive lining that helps to bond the tubing to underlying cables and connectors, forming strong seals that can often be waterproof. Another material that is sometimes added to heat shrink tubing is conductive polymer thick film, which provides an electrical connection between the two or more conductive objects that are being joined by the tubing — without the need to solder them first.


You've probably noticed that most plastics you encounter won't just shrink down if they're heated — so what makes heat shrink tubing different? The answer is cross-linking, the process of exposing a polymer to radiation in order to create covalent bonds between that polymer's atoms. Following World War II, it was discovered that radiation could alter the molecular structure of certain plastics so that they wouldn't melt or develop a flowing consistency, no matter what temperatures they were exposed to. Covalent bonds also give polymers plastic memory, which means that once a polymer has been cross-linked and stretched into an expanded shape, it will automatically shrink back to its original dimensions when a certain amount of heat is applied.


Each type of heat shrink on the market is labeled with a shrink ratio, or the measurement of how small the tubing becomes when shrunken in comparison to its original expanded size. For example, heat shrink tubing with a 2:1 shrink ratio has an expanded diameter that is twice the size of its shrunken diameter. Likewise, a 6:1 ratio indicates that a piece of heat shrink is capable of shrinking to 1/6th of its expanded size. These, of course, aren't the only shrink ratios out there; a wide variety is available on the market, but their ratios can all be interpreted as easily as the two examples just given.


Likely to be found just about anywhere there are cables and wires, heat shrink is extremely useful, both for protection and cosmetic enhancement. It can be used to:

  • • Seal water and dust out of cable splices
  • • Insulate cables and wires against extreme heat in aircraft, boats, and military vehicles
  • • Provide a barrier between cables and corrosive chemicals
  • • Color code cables for easy identification
  • • Harness multiple wires together
  • • Make long-lasting labels for network patch cords
  • • Neatly terminate the ends of braided sleeving
  • • Improve the look of cables in computer case mods or custom cars and motorcycles

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