Flexible tube of extreme suppleness - has a waterproof layer sandwiched between layers of porous plastic of special microstructure

摘要

Tube consists of three layers. The inner layer is of a porous polymer with a microstructure of nodes joined by fibrils. Over this is wound a waterproof layer, and over that a further layer of the porous polymer. Pref. the layers are connected together by adhesive and the porous polymer is PTFE or polypropylene. The middle, waterproof layer is pref. of a flexible plastic, partic. tetrafluorethylene-hexafluoropropylene copolymer a fluorhydrocarbon polymer with perfluoralkoxy side chains, a fluorelastomer or a plastic-backed metal foil. Tubes can be bent to a radius of only 5-15 times their own dia. without kinking or collapsing. They bend easily and remain watertight after repeated bending.