| 摘要 |
1518424 Coiled tube IMPERIAL-EASTMAN CORP 12 Feb 1976 [24 Feb 1975] 05618/76 Heading F2P A flexible coiled tubing 10 is formed of a polyester which has been successively softened by heating and reset by cooling, the polyester comprising the polycondensation product of at least one aromatic dicarboxylic acid having a molecular weight below 300 with a polyalkylene ether glycol having a molecular weight of from 400 to 6000 and at least one diol having a molecular weight below 250. The scale D durometer hardness of the polyester may be from 44 to 63, the elongation at break may be from 500 to 8,000 and -the flex modulus, according to ASTM-D-790 of from 7,000 to 60,000. The polyester may be plasticized polyethylene terephthalate in which a minor amount of ethylene glycol units is replaced by units of the polyalkylene ether glycol A reinforced braid may be provided about the outer surface of the tube and a sheath of a fully polymerized high molecular weight non-reactive thermoplastics material may cover the braid. The tubing 10 is formed by extrusion from an extruder 11 at a temperature of about 500‹ F. and is then drawn through a cooling device 12 by a haul off device 13. The tubing is then coiled and allowed to cool. The cooled tubing is then passed through a heating apparatus 14 to raise its temperature to an annealing temperature and is then formed into a helical configuration by guide rollers 15. The coil is then cooled to set in this configuration. |
