Patent ID: 6887539

Claim:
A heat shrinkable tube formed of a polyolefin resin composition, wherein said polyolefin resin composition comprises: (A) 60% or more of middle to high density polyethylene defined in the following ranges: (a) molecular weight distribution (Mw/MN) of 30-55, wherein Mw represents weight-average molecular weight and MN represents number-average molecular weight; (b) melt flow rate (MFR) of 0.05 to 0.2; and (c) specific gravity of 0.94 to 0.96; (B) phenol resin-based antioxidant, (C) sulfur-based antioxidant, and (D) zinc oxide, and, said polyolefin resin composition is formed into a tube, then, cross-linked by irradiation by an electron beam, and the tube is expanded in diameter at temperatures of not lower than softening point, said expanded tube having a concentricity of 25% or less, where the concentricity is equal to (maximum wall thicknessâˆ’minimum wall thickness)/maximun wall thicknessÃ—100.