| 摘要 |
1,080,332. Films; quenching extruded tubing. J. TAGA. Oct. 20, 1964 [Oct. 22, 1963; Nov. 17, 1963], No. 42804/64. Headings B5A and B5B. Plastic tubing is made by extruding a molten thermoplastic material in tubular form, the tubing being inflated by gas, and continuously withdrawing the inflated tubing in a substantially vertical direction through an opening in a quenching member, and directing a stream of quenching liquid over the quenching member in a direction having a component in an inward radial direction, to contact the outer surface of the tubing so that the quenching liquid is continuously changed in such a manner that the volume of quenching liquid carried by the quenching member remains constant and the surface of this quenching liquid remains smooth so that the tubing is quenched uniformly without wrinkles or streaks on its surface. Thus, as shown, in Fig. 1, the liquid is horizontally, centripetally and continuously supplied over the quenching disc 4 from an annular slit opening 10 provided circumferentially around the quenching disc. This liquid is introduced at 16, the rate of flow being regulated by valve 17, and ripples are prevented from reaching the film by the circumferential wall 15. Liquid passes to the film surface as indicated by the arrows, and drains over the weir 20 into annular trench 21, formed by weir 20 and flange 18, and is removed at 22. Flange 18 is in threaded engagement with wall 19 and this permits the depth of liquid surrounding the film to be varied. Quench ring 4 fits as shown into the annular wall 12 and can be readily removed and replaced by a quenching disc having a central opening of different diameter. In the apparatus of Fig. 3, the liquid 9 is upwardly and continuously supplied along the external surface of the tubing from an annular slit opening 10 provided circumferentially around the quenching disc 4 so that the surface of the liquid is swollen by surface tension. Specified thermoplastic materials include polyethylene, polypropylene, polyamides and polyvinylidene chloride. Specified quench liquids include water. |
