Sealing characteristics of polypropylene adhesive tape
Polypropylene adhesive tape heat shrinkable tubing has been used for communication cable joint sealing for nearly 20 years. It is mainly used for gas-filled network joints inside cables or to prevent moisture from entering the cable body. The sealing pressure is relatively small. It has not been reported that it is used for external pressure sealing and the sealing pressure is very high. According to relevant information, the Japanese offshore submarine cable connection box is sealed with a heat-shrinkable sleeve, but its sealing performance is only 2MPa. The heat-shrinkable sleeve is made of polyolefin raw materials and various additives, through molding, y-ray radiation cross-linking, and expansion processing. Polypropylene adhesive has high mechanical strength, use temperature, chemical resistance and aging resistance | energy. Its 'elastic memory effect' makes it have heat shrinkability, that is, when it is heated again, it can return to its original shape and size. Using this feature, it is possible to seal the through hole of the optical cable sealing head. Since the outer sheath layer of the optical cable is made by extrusion process, the size of the outer sheath will inevitably produce unfavorable factors such as large dimensional tolerance range and non-round outer diameter, which will affect the axial direction of the outer sheath layer of the optical cable. Sealing brings difficulties. The polypropylene adhesive tape is not limited by the size of the cable body when it is heat-shrinked, and it shrinks evenly and tightly wraps the cable body. Coupled with the gap-filling effect of the hot melt glue that melts when the heat shrinkable sleeve is heated, It is very suitable for the axial sealing of the cable body.