The middle wall heat shrinkable tubing and the double wall heat shrinkable tube are almost the same in general. There are four differences as follows:
1, the diameter of the tube is different: the diameter of the middle-wall heat-shrinkable sleeve is larger than that of the double-wall heat-shrinkable sleeve, and its softness is relatively smaller.
2, the inner coating method is different, the double-walled tube is extruded at the same time, the middle wall tube coating method is divided into direct coating and spiral coating.
3. The heat-resistant degree is different. The middle-wall heat-shrinkable tubing can work continuously at - 55 ~105 C, the lowest initial shrinkage temperature is 80 C, and the lowest complete shrinkage temperature is 120 C. It is basically the same as the double-wall tube, except that the highest use temperature of the double-wall tube can reach 125 C, while the heat-shrinkable middle-wall casing can work continuously on the heat-shrinkable tube at 105 C, in fact, at the highest temperature. The service life of the materials will also be greatly shortened, and their low temperature brittleness is better. They can work continuously at temperatures above - 55 C without brittle cracking.
4, the degree of withstanding high voltage is different: the middle wall heat shrinkable sleeve is widely used in the insulation sheath seal of 10KV cable (1mm breakdown strength (> 25KV) because of its thicker thickness and strong voltage resistance. The general pressure withstanding level of double-wall heat-shrinkable tubes is 0.6KV.
The fluxes of double-wall heat shrinkable tubes have the following functions:
1. Corrosion resistance: resistance to seawater, grease, acid, alkali and other chemical corrosion, anti-bacterial, non-toxic, tasteless, pollution-free;
2. Sound insulation: sealing double-wall heat-shrinkable tube bubbles, sound insulation effect is good;
3. Thermal insulation: heat insulation, cold insulation and low temperature performance is excellent, can withstand cold and exposure;
4. Processing: No joints, and easy to hot-press, cutting, gluing, bonding and other processing.
5. Water resistance: Closed cell structure, non-water absorption, moisture-proof, water resistance is good;
6. Vibration proof: high resilience and tension resistance, high toughness, good shock proof/buffer performance.
The full name of mid-wall heat-shrinkable tube is heat-shrinkable medium-wall thickness tubing, also known as heat-shrinkable mid-wall pipe, medium-wall heat-shrinkable tube, mid-wall casing, referred to as mid-wall pipe. Usually there is only one color in the middle wall heat shrinkable tube, black. Radiated polyethylene is the material of mid-wall heat-shrinkable pipe. Because of its large diameter and relatively small flexibility, it is one of the reasons why mid-wall heat-shrinkable pipe is widely used in warships and ships. Medium-wall heat-shrinkable tubes are widely used in insulation sheath seals of 10KV cables (1mm breakdown strength (> 25KV) because of their thicker thickness and high voltage resistance.
Peeling strength is one of the special technical parameters of mid-wall heat-shrinkable tube. Peeling strength (> 125N/25) is usually designed in the industry. To meet this requirement, the mid-wall tube can give full play to the role of protection and sealing, which is closely related to the performance of the hot melt adhesives inside the mid-wall tube.