How shall I choose Heat-shrinkable Tubing with Adhesive (Dual Wall Heat Shrink Tubing)?

It’s often to receiving the phone with the following questions.

=> The tubing slided after shrinking!  Could you improve the situation?

=> This wire-harness will be applied to the engine, and it needs to be resistant to high temperature and oil.  What kinds of heat-shrinkable tubing with adhesive do you suggest?

=> The outer diameter of the two parts is much different, will the smaller end not be covered?

=>  BOM cost was refused by sales dept. again!  Please recommend a cheaper heat-shrinkable tubing!

Indeed, we receive many queries about all kinds of heat-shrinkable tubing everyday.  So, as the curator of Good Gi, I'll share some useful information about the application and selection of heat-shrinkable tubing with adhesive.

What is Heat-shrinkable Tubing with Adhesive (Dual Wall Heat Shrink Tubing)?

Heat-Shrinkable Tubing with Adhesive, also known as the Dual Wall Heat Shrink Tubing, Dual Wall Adhesive-Lined Heat-Shrink Polyolefin Tubing, or Adhesive Lined Heat Shrink Tubing, is a product widely used in insulating and protection with its mature technology.   It is different from single wall heat-shrinkable tubing with its special feature:  the tube wall is coated with hot-melt glue.  When heated, the tube shrinks, in the same time, the glue melts and flows to cover the cable or the bare copper wire so that it brings the waterproof and dustproof effect.  As it has better sealing performance and tensile strength than single wall heat-shrinkable tubing, the heat-shrinkable tubing with adhesive will cover the component according to the shrinkage ratio to achieve the functions of protection, insulation, and heat insulation.  This tube is often used in daily necessities, 3C products, aviation, navigation, and the military.

Types of Heat-shrinkable Tubing with Adhesive (Dual Wall Heat Shrink Tubing):

Most of heat-shrinkable tubings with adhesive are made from cross-linked polyolefin (XLPE), and the difference of this material lies in the shrinkage ratio, high or low-temperature resistance, and softness & hardness.

3:1 heat-shrinkable tubing with adhesive - the most popular type in various industries.

After the tubing is irradiated by radiation, the long-term working temperature can reach 125 °C.  This tubing is soft with good ductility, anti-UV, and can resist to high-temperature, acid, and alkali.

Triple shrinkage ratio is sufficient for most applications, and the temperature resistance is available at 125°C and 135°C, which is the most cost-effective option.

4:1 heat-shrinkable tubing with adhesive - with four times the shrinkage ratio. 

Higher shrinkage ratio, and the temperature resistance are available at 125°C and 135°C.

4:1 Semi-rigid heat-shrinkable tubing with adhesive – with four times shrinkage ratio, and semi-rigid polyolefin material in the outer layer.

With higher wear resistance and mechanical strength.  Mostly used in harsh environments, such as automobile engines, and ships.

How shall I choose Heat-shrinkable Tubing with Adhesive (Dual Wall Heat Shrink Tubing)?

It depends your applications.  For general electronic products or automotive wiring harnesses with protection jacket, normal heat-shrinkable tubing with adhesive (dual wall tubing) has sufficient weather resistance already.  But, if you’ll use it in the environments with rubbing or stress or outdoors, we’d recommend the semi-rigid heat-shrinkable adhesive tubing (dual-wall tubing) which has high mechanical strength.

The hot melt glue inside the tubing will re-melt when heated, we call it reversible.  For most of heat-shrinkable tubing with adhesive (dual wall tubing) in the market, the glue material is EVA hot-melt adhesives (ethylene vinyl acetate).   However, if prolonged exposure to high-temp environment, and the shrinkage part of tube is strained, the glue melting and sliding may occur.  In such situation, Good Gi Co., Ltd can customize polyamide hot melt adhesives (Polyamide, PA, commonly known as Nylon) for users, which can ensure the functionality at 125 °C for a long time, as well as for products need to conduct Aging Reliability test (temperature 85°C, humidity 85%, above 1000hrs).

How do we use Heat-shrinkable Tubing with Adhesive (Dual-Wall Heat Shrink Tubing)?

Put on the heat-shrinkable tubing with adhesive (dual wall tubing) to the component, and go heating.  It starts shrinking at 75°C above.  And it is recommended to heat up to at least 115°C to speed up the shrinkage efficiently and completely.