What is heat shrink tubing and what is it for?
Heat shrink tubing, also known as shrink tubing, is a tubular material used in a variety of applications to protect, insulate, or bundle electrical cables, wires, and electronic components. It is made of thermoplastic polymers, such as polyolefin, polyethylene or PVC (polyvinyl chloride), which have the property of shrinking when heat is applied to them.
The heat shrinking process involves heating the tube with a heat source, such as a heat gun or oven, which causes the material to shrink or contract evenly around the object being covered or protected. This creates a solid, insulating coating that protects cables or components against moisture, dirt, corrosion and mechanical wear, as well as providing electrical insulation.
Heat shrink tubing is used in a wide range of applications, such as the electronics, automotive, aerospace, marine and plumbing industries. It is a versatile and effective solution for cable management and protection of electrical connections, and is found in different sizes, colors and types to suit various needs. It may also contain thermoplastic adhesives inside to provide an airtight seal on electrical connections and prevent the entry of moisture or external substances.
Heat shrink tubing is manufactured in a multitude of varieties and chemical compositions, and the exact composition of each type depends on the intended application. From almost microscopically thin-walled tubes to thick-walled rigid tubes, each type has precise design and chemical additives that make it suitable to meet a wide variety of environmental demands.
What types of heat shrink are there?
At Electronica Embajadores you can find the following types of heat shrink available:
Irradiated polyolefin, sometimes called irradiated polyolefin heat shrink tubing, is a specific type of heat shrink tubing that is manufactured from polyolefin that has been subjected to ionizing radiation to modify its properties. This irradiation process makes irradiated polyolefin especially suitable for electrical insulation and shielding applications in demanding environments.
Some of the features and advantages of irradiated polyolefin include:
Excellent electrical insulation: Irradiated polyolefin has a high dielectric strength, making it ideal for the insulation of electrical cables and connections.
High heat resistance: It is capable of withstanding elevated temperatures, making it suitable for applications where prolonged exposure to heat is expected.
Excellent chemical resistance: It is resistant to a wide variety of chemicals, making it suitable for corrosive environments.
Good flexibility: Despite its strength, irradiated polyolefin is usually flexible, making it easy to install and apply in areas with curves or irregular shapes.
Uniform Shrinkage: Like other types of heat shrink tubing, irradiated polyolefin shrinks evenly when heat is applied, ensuring a tight, secure fit.
Moisture Protection: Its ability to tightly seal connections also makes it effective in protecting against moisture and other environmental elements.
Irradiated polyolefin is commonly used in the electrical and electronics industry for the insulation and protection of cables, terminals and connections, as well as in repair and maintenance applications. Due to its improved properties, it is especially useful in situations where a high level of electrical insulation and durability is required.
Commercially there are 2 widely used contraction ratios, to which in some cases an interior adhesive has been added to improve its properties:
Irradiated polyolefin heat shrink with 2:1 shrink ratio without inner adhesive
This is the most widely used heat shrink tubing in electronics. Its characteristics are the following:
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- Retraction: Up to 50%
- Continuous temperature: -55ºC to 125ºC
- Elongation at break: 200% minimum
- Drilling voltage: 20,000V/mm thickness
- The wall is thin so it can be easily bent without contracting.
Irradiated polyolefin heat shrink with 3:1 shrink ratio without inner adhesive
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- Retraction: Up to 33%
- Continuous temperature: from -55ºc to 110ºC
- Elongation at break: 400%
- Dielectric strength: 20,000v/mm
- The wall is thin so it can be easily bent without contracting.
- By shrinking more than the 2:1 ratio for the same resulting diameter, the tube wall becomes thicker and more rigid. Voltage insulation is greater at the cost of losing flexibility
Irradiated polyelefin heat shrinkable with interior adhesive
Same as the previous one but in this case a hot melt adhesive glue has been added. The good thing about this shrink tube is that when heated it shrinks and the glue melts at the same time, heat-sealing not only the interior, since when it shrinks, all the excess glue comes out, leaving everything heat-sealed, which provides excellent insulation. For all these reasons, it is more suitable for outdoor splicing.
Thin Wall 3:1 Shrink Ratio Irradiated Polyolefin Heat Shrink with Inner Adhesive
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- Continuous temperature: from -55ºc to 110ºc
- Dielectric strength: 20,000v/mm
- Elongation at break: 400%
- Self-extinguishing
Thick Wall 3:1 Shrink Ratio Irradiated Polyolefin Heat Shrink with Inner Adhesive
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- Continuous temperature: from -55ºc to 110ºc
- Dielectric strength: 20,000v/mm
- Elongation at break: 250%
- Self-extinguishing
- The unshrinked thickness is approximately 1mm. It cannot be folded.
- Supplied in 1 meter tubes or bars.
- Having a thick wall increases the insulation compared to that with a thin wall
PVC heat shrinkable
PVC shrink tube in electronics is mainly used in battery packs. It is more economical than irradiated polyolefin and its common characteristics are:
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- PVC Heat Shrink Tubing
- Retraction: 48 ± 5%;
- Continuous temperature: - 40º ~ 105ºC
- Maximum temperature: 105ºC
- Maximum voltage: 600V
- It is more rigid than polyolefin, so it is not usually used in electrical cable splices.
Heat Shrink Tubing Kits
Since irradiated polyolefin heat shrink tubing without interior adhesive is widely used in electronics, it is common to find kits packaged in different diameters and/or colors. At Electronica Embajadores we have provided kits of different sizes in black as it is the most used and also kits with heat shrinkable tubes in assorted colors in various sizes. The characteristics of these tubes are the same as those of the irradiated polyelefin tube (without interior adhesive) mentioned above.
Heat Shrink Splice with Tin Ring
These heat shrinks are small PVC tubes, to which hot melt glue and a tin ring have been added that melt when the assembly is heated. This heat shrink allows two conductor cables to be spliced by soldering them.
In the end, the assembly is heat-sealed by the glue inside the heat-shrinkable film.
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1: heat shrink tube
2: waterproof hot melt glue
3: with color code (different diameters)
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