| 摘要 |
PURPOSE:To highten kink resistance and restoring property of a tube by keeping the ratio of the thickness of the projected part to the thickness of the recessed part on the inner surface of a tube >=12. CONSTITUTION:Recessed parts 2 and projected parts 3 are formed on the inner peripheral surface of the tube 1 composed of flexible resin. The ratio t1/t2 of the thickness t1, of the projected part 3 to the thickness t2 of the recessed part 2 is kept at, at least, 12. Further the rate n/m of the sum(n) of the upper end- width of each projected part to the length(m) of the circle having the distance from the center to the projected part 3 in the cross section of the tube 1 as radius, is kept between 20-80%. By providing the projected parts of 2-20, a desired flexible tube is obtained. The flexible resin is the resin composed of single or at least two kinds of the ethylene alpha-obefine copolymer composed of ethylene and alpha-obefine of the carbon number of 3-10. The melt flow rate of the resin is 0.5-100g/10min and its density is 0.850-0.900g/cm<3>. This tube is excellent is kink resistance and restoring property. |
