The Shrinkage Principle Of Heat-shrink Pre-insulated Tubing

The outer layer of pre insulated sleeve is made of high-molecular polyolefin material, providing wear resistance and flame retardancy; the inner layer is laid with a hot melt adhesive layer, which shrinks synchronously with the outer layer during heating. When the temperature reaches the operating range of 70-125℃, the outer wall begins to shrink radially, and the inner adhesive melts and flows accordingly, ultimately forming a comprehensive seal for the conductor. This shrinkage ratio is typically 2:1 to 3:1, adaptable to the connection needs of cables with different wire diameters.

The installation of pre insulated junction sleeve requires precise temperature control. Technicians use a hot air tool to heat the material evenly along the axial direction, gradually adhering it to the terminal surface under the influence of heat. After shrinkage, the inner hot-melt adhesive fills all the tiny gaps, forming a continuous waterproof barrier. Compared to the multi-layer wrapping method of traditional insulating tape, this integrated process significantly shortens the construction cycle of insulated joint sleeve while eliminating the risk of interlayer peeling.