Double-walled heat-shrinkable tube, as the name implies, is a two-layer heat-shrinkable tube which differs from single-walled heat-shrinkable tube mainly in the number of layers, double-walled heat-shrinkable tube has an additional layer of hot-melt adhesive layer, in addition, double-walled heat-shrinkable tube and single-walled heat-shrinkable tube in the production process, scope of application, placement conditions and other aspects of certain differences. The double-walled heat shrink tube is mainly used in places with high requirements for waterproofing, as the hot-melt adhesive on the inner layer can form a waterproof layer, playing a waterproof and moisture-proof effect.

The main difference between the two lies in the number of layers, as can be seen from the name, double-walled heat-shrinkable tubes are double-layered and have an internal layer of hot-melt adhesive: single-walled heat-shrinkable tubes have only one layer, which is the ordinary heat-shrinkable tube. In addition to the difference in the number of layers, the difference between double-walled and single-walled heat-shrinkable tubes are:

1、Different production processes

Single-walled heat-shrinkable tube is a tubular intermediate product made of polymer or polymer alloy by extrusion, then irradiated (or chemically) cross-linked, heated and expanded, cooled and shaped to a certain size; double-walled heat-shrinkable tube is made of high-quality cross-linked polyolefin material in the outer layer and hot-melt adhesive in the inner layer.

2、Different scope of application

Double-walled heat-shrinkable tube with insulation, sealing, waterproof, anti-corrosion, air leakage and other functions, mainly used for wiring waterproof places, to protect the cable from corrosion and seepage of water; single-walled heat-shrinkable tube is not waterproof, can not be used in a wet environment, only for ordinary places

3、Different placement conditions

Single-walled heat-shrinkable tube without hot-melt adhesive, its placement requirements are low and can be placed for a long time: double-walled heat-shrinkable tube inside the hot-melt adhesive placement requirements, and should not be placed for a long time, otherwise the internal hot-melt adhesive may fail, affecting the normal use of the heat-shrinkable tube.

Double-walled heat-shrinkable tubes are mainly used in places with high requirements for waterproofing, so can double-walled heat-shrinkable tubes really be waterproof?

Generally speaking, ordinary heat-shrinkable tubing is single-walled and has no waterproof function, while double-walled heat-shrinkable tubing has an internal layer of hot-melt adhesive. When heating double-walled heat-shrinkable tubing, the internal hot-melt adhesive will turn into fluid at high temperature and fill the gap between the heat-shrinkable tubing and the protected cable; after heating is over, the hot-melt adhesive cures to form a waterproof layer, which can prevent water and water vapour from entering, thus playing a waterproof and moisture-proof effect. Therefore, in some occasions where cable wiring needs to be waterproof, double-walled heat-shrinkable sleeving is often used.