RADIATED MODIFIED SELF-SEALING COLD-APPLIED TAPE POLYLENE AND METHOD OF ITS MANUFACTURE Russian patent published in 1997 - IPC

FIELD: assembly and repair of pipe lines. SUBSTANCE: tape is manufactured by extrusion from laminar polyethylene base with addition of butyl rubber. Tape is radiated by electron beam to obtain gel fraction in first layer in amount of from 2 to 15 percent. Second layer is polyethylene and next layers contain additional of butyl rubber increasing from 8 to 60 percent. Last layer is made from butyl rubber. Thickness of layer of tape containing gel fraction is equal to 30 to 70 percent of thickness of tape. Tape is subjected to thermally-oriented extrusion by 12 to 25 percent at temperature of 80 to 95 C. EFFECT: enhanced efficiency. 6 cl, 1 dwg