The invention relates to a heat-shrinkable tube, in particular to a semiconducting
halogen-free
flame retardant double-wall heat-shrinkable tube and a preparation method thereof. The tube consists of an outer
wall material and an inner
wall material. In parts by weight, the outer
wall material contains 43 parts of first
polyolefin mixed resin, 10 parts of graphitized
carbon black, 10 parts of first assistant and 37 parts of
flame retardant, and the inner wall material contains 53 parts of second
polyolefin mixed resin, 10 parts of second assistant and 37 parts of
flame retardant. The preparation method comprises the following steps of: preparing the inner and the outer wall materials of the double-wall heat-shrinkable tube, extruding, irradiating and expanding molding. Compared with traditional shrinkable tubes, the double-wall heat-shrinkable tube has the technical characteristics that the special
halogen-free flame retardant is employed in the
raw material, and therefore, products have good flame retardant effect, high
temperature resistance and good performance, and the
pollution can not be generated even if the products are burnt; the cost is lowered, obvious
economic benefits and
environmental protection effects are obtained, thereby being suitable for large-scale popularization and application.