Process and apparatus for manufacturing tubular fi

专利名称：Process and apparatus for manufacturing

tubular films of synthetic thermoplasticmaterials

发明人：CAPPUCCIO VITTORIO E.申请号：US37376764申请日：19640609公开号：US3275723A公开日：19660927

摘要：1,009,294. Tubular films. MONTECATINI SOC. GENERALE PER L'INDUSTRIAMINERARIA E CHIMICA. June 2, 1964 [June 20, 1963], No. 22814/64. Heading B5B. Atubular film of a synthetic thermoplastic material is extruded in a heat-softened conditioninto a quenching liquid bath, pulled through the bath in collapsed condition, and, as thecollapsed film tubing is pulled out of the bath in a direction which is vertical or within 45degrees of the vertical, a spatially stationary bubble of the film tubing is formed andmaintained during the extrusion process, vibrations being applied to said bubble in adirection substantially transverse to the length thereof to thereby dislodge any dropletsof liquid from the inner surface of the bubble and collect them in a bottom section of thebubble. Specified thermoplastic materials include polypropylene and vinyl and vinylideneresins. A charge of solid absorbent for the liquid, suitable in granulated form, may bemaintained in the bubble, preferably in the bottom section only of the bubble. Specifiedabsorbents include silica-gel, anhydrous sodium sulphate, magnesium sulphate,

potassium carbonate, anhydrous copper sulphate and activated alumina. In the Figure, atubular film 4 is extruded from die 3, inflated with air or other gas, e.g. nitrogen, supplied

through conduit 5, quenched in the water bath 6 and collapsed between collapsers 9. Thecollapsed film is pulled through the bath by pinch rolls 8, deflected vertically upwardlyaround guide roll 10 and taken up by a further pair of pinch rolls 11, placed above thetank 7. A bubble 46 is formed between the de-collapsers 13 associated with rolls 11 andthe collapsers 14 associated with rolls 12. A gas such as air is contained in the bubble andtransverse vibrations are imparted to the film by ultrasonic electroacoustical transducers17, energized at a supersonic frequency by an electrical oscillator 18. A frequency of20,000 c.p.s. is preferred. Electro-magnetic or mechanically operated vibrators may beused, operating if preferred at sonic frequencies. Thus any liquid droplets or particles ofabsorbent fall to the bottom section of the bubble. A charge 15 of pelletized absorbent15 is contained in the bottom section of the bubble. When the charge 15 becomesloaded with the absorbed liquid, or where no absorbent is used, when the liquid poolreaches a certain depth, extrusion is stopped and the tube is severed. Cuts may be madejust beyond points 11, 12, or a single cut can be made just below 17 and the bubblecontents poured away. In the latter case, it is advantageous to support the lower pair ofpinch rolls 11 and de-collapsers 13 by mounting means, indicated at 20, capable ofrotation through 90-100 degrees in the direction of arrows F.

申请人：MONTECATINI SOCIETA GENERALE PER L'INDUSTRIA MINERARIA E CHIMICA

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