| 摘要 |
1332132 Film or sheet extrusion; laminates BELOIT CORP 22 Sept 1970 [25 Sept 1969] 45092/70 Headings B5A B5B and B5N An extrusion die comprises two or more, e.g. three, parallel extrusion orifices 74, 76, each supplied from the same or different extrusion sources and from which the extruded sheets or films, e.g. of polyethylene, polypropylene, nylon, polyvinylchloride, or wax, whilst still in a plas. tics condition are laminated together, and optionally to a pre-formed sheet, each end of one or other of the orifices 74, 76 extending beyond the other to overlap, in the plane of the extruding sheets, by an amount to avoid excessive thickness at the edges of the laminated sheet arising from lateral contraction of the issuing extrudate, and the die passages leading to each extrusion outlet being heated by independently regulable means. In the Fig. 1 embodiment the die comprises a bolted together assembly 50, 52, 54, defining respective flow paths 62, 66, 70 and 64, 68, 72, leading at centrally located passages 46, 48 from separate extrusion sources, and is provided with a number of independently rheostat controlled cast-in aluminium electrical heaters 44 along each side, and with independent adjustment of the depth of each orifice 74, 76 by flexing of the die lips by means of screws 88, 90. The overlap of the length of the orifices at each end is obtained by deckles comprising external stepped blocks (120, 122), Fig. 2 (not printed), held in place by members, e.g. 100, locating in the die at 116, 118. The overlap may comprise the same or different orifices at each end. The die entrance passages 46, 48 may alternatively be located vertically or at an angle to and/or at the ends of the orifices 74, 76. In alternative constructions, the deckles may comprise shims within the orifices or, Figs. 6 and 7 (not printed), the deckles may be located within the die at the entrance to the lands. The extrudate to be applied as a coating to a preformed sheet may be heated by the differentially controlled heaters to a higher temperature than the other extrudate. In the Fig. 8 embodiment (not printed), the extrudates (220, 222) are brought together by an air knife (252) and laminated during passage through successive nips of a three chill roll arrangement. In the Fig. 9 embodiment, a paper or cloth sheet 232, delivered over a roll 230, is coated with the extrudates 220, 222 during passage between a pivotally mounted rubber roll 234 and a chill roll 236. In the Fig. 10 embodiment (not printed), the extrudates are laminated by extrusion from a die pivotally inclined at 15 to 20 degrees to the vertical, being brought together by an air knife and cooled by passage through a water bath, subsequent to which is located opposed wipers for removal of superfluous water. |
