Heat Shrink Materials are made up of crosslinked thermoplastic elastomers that contracts or “shrinks” when exposed to heat. This characteristic allows it to tightly wrap around electrical conductors and termination part, providing insulation, weather stability and chemical resistance.
During World War II, the military searched for a better way to insulate wires in aircraft and vehicles- something light, durable, and reliable. Scientists discovered that certain plastics, like polyvinyl chloride (PVC), shrink when heated. This shrinking action created a tight seal over joints, providing insulation and protection. As a result, engineers first used these materials in aerospace applications and then quickly expanded their use into the automotive, telecom, and power industries.
Types and Functions:
1) Single Wall Tubing
We call it single-wall because it contains only one layer of Heat Shrink Materials. It has no inner adhesive or extra coating- just a single outer wall that shrinks tightly when heat is applied. Manufacturers typically use materials like Polyolefin, PVC, or Fluoropolymers to make this tubing. They choose these materials for their durability, flexibility, and ability to withstand heat during the shrinking process.
Electricians and engineers often use this type of tubing for electrical insulation, wire bundling, and control panels, as it reliably handles everyday insulation needs. Single-wall tubing usually comes with a shrink ratio ranging from 2:1 to 4:1. For example, a 2:1 ratio means the tubing shrinks to half its original diameter when heated. So, if it starts at 10 mm, it will shrink down to 5 mm. This allows the tubing to grip wires, terminals, or connectors of various sizes tightly, creating a snug and secure fit.
2) Double Wall Tubing.
This type consists of two layers. The outer layer uses Heat Shrink Materials that shrinks with heat to provide insulation and mechanical protection. The inner layer contains hot-melt adhesive that melts to form a waterproof seal against moisture, dust, and contaminants. Manufacturers also produce adhesive-lined, heavy-wall, and Kynar tubing for specific applications using various materials.
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3) Heat Shrink Termination Kits
Engineers use these kits for low and medium voltage applications. They apply them at the point where the cable connects to the equipment, providing insulation and sealing. These kits help prevent leaks and short circuits in electrical systems while protecting the termination point from moisture, dust, and mechanical stress. This enhances the stability and durability of the connection.
Manufacturers use cross-linked polymers to produce these kits because of their excellent insulation properties and strong resistance to heat in outdoor or industrial environments. You’ll commonly find these kits installed in power distribution networks, substations, and industrial sites.
4) Straight Through Joints
Technicians use these joints to connect two cable segments, creating a continuous and insulated link. They design them for single-core and three-core cables that operate across low to high voltage ranges.
Manufacturers construct these joints from crosslinked polyolefins to provide insulation against electrical faults and withstand the high temperatures found in live cable environments. After shrinking the material, it resists cracking, abrasion, and physical stress. It also protects against moisture, oils, and chemicals. The material grips the joint tightly, forming a secure and lasting seal.
Professionals typically install these joints in sectors like telecommunications, railways, construction, and power transmission and distribution. These industries rely on robust and sealed joints to protect cables from moisture ingress, mechanical stress, and environmental damage. In railways and power networks, the joints handle high voltages while resisting vibration and weather changes. In telecommunications and construction, they help prevent signal loss and ensure continuous power flow in both buried and exposed cable systems.
5) Heat Shrink Molded Products:
These Heat Shrink Materials come pre-shaped and shrink tightly around objects when heated. Engineers use them to protect and insulate wire and cable harnesses, cable ends, and connectors across the automotive, electronics, and aerospace industries.
Manufacturers mold these products into specific shapes-such as end caps, rain sheds, right-angled boots, and breakouts based on application requirements. They use crosslinked thermoplastic materials that shrink under heat to create a tight, protective seal around the object. When technicians place them over the item and apply heat, the material conforms closely to the shape, delivering insulation, mechanical protection, and a waterproof seal.
Unlike heat shrink tubes that only cover uniform cable profiles, these molded components fully seal areas where cables split, bend, or connect at unusual angles. In these cases, they provide the tight seal and full protection that conventional tubing cannot.
At Axis, we have a team of 50+ engineers who can help you with choosing, applying, and testing heat shrink solutions. Customers worldwide use our products in solar farms, substations, data centers, factories, and everyday residential and commercial projects.