| 摘要 |
1. A flat die for the extrusion of multi-layered and multi-coloured films, sheets or plates of plastics material, in which die channels (12, 13, 14), for supplying plastics materials of different colours to an intermediate layer (A, B, C), open into a cavity positioned transversely with respect to the direction of extrusion, which leads into a smooth passage (15) in which the intermediate layer of the film, sheet or plate is formed, and which, before emerging from the outlet (6) of the die, joins with two other ducts (16, 19) which are linked to channels (18, 22) for distributing the plastics materials intended for forming a support layer (D) and a covering layer (E) respectively, the above-mentioned cavity containing a means for spreading out, in the intermediate layer (A, B, C), the streams of plastics material admitted by the supply channels (12, 13, 14), the flat die being characterised in that said means comprises a thin fixed plate (7) the upper face of which is provided with raised teeth (9) having a height and a width which decrease from their upstream end to their downstream end where they end in a point, the teeth (9) delimiting trapezoidal spaces (10), the profile of which, considered in a plane which is parallel to the base plane of the plate (7), increases from upstream to downstream in such a way that the spaces (10) are in contact at their downstream ends, each of these spaces (10) being supplied with coloured plastics material (A, B, C) by the channels (12, 13, 14) which introduce the plastics material into the trapezoidal spaces at their upstream ends and moving in the direction of extrusion. |
