| 摘要 |
1,168,933. Extruding foamed resins. FMC CORP. 9 April, 1968 [31 May, 1967], No. 17006/68. Heading B5A. [Also in Division C3] A shaped foamed product formed of polymeric material having cells which are aligned is claimed and may be made by extruding a stream of flowable polymer through an elongated orifice as a shaped product, e.g. sheet, a gas being introduced under pressure into the stream at spaced intervals concomitantly with its passage through the extruder, permitting the gas to expand as the polymer issues from the orifice to provide a series of cells and setting the polymer. The polymer may be a polymer of ethylene, propylene, styrene or vinyl chloride, or viscose or cellulose acetate. Figs. 1-3 show an apparatus for making the foamed product wherein an extruder 11 has molten polymer in 13 which is fed via 15 through breaker plate 17 to orifice 33 while a gas under pressure is fed via a vertically adjustable aerating member 37 through perforations 51 which are aligned; on leaving 33 the molten polymer is under reduced pressure so that cells are formed, the foam is quenched, e.g. by cool air or liquid bath, and then may be stretched. |
