| 摘要 |
1,212,682. Producing extruded sheet materials. O. B. RASMUSSEN. 29 Dec., 1967 [30 Dec., 1966], No. 58429/66. Heading B5B. A melt extruded sheet material comprises lamellµ of a first material, which is polymeric, and lamellµ of a second, different, material, the lamellµ of the first and second materials being interspersed with each other and intimately adhering to one another, each lamella of the first material traversing part at least of the thickness of the sheet material and being, over at least a substantial part of its surface area, between 0À1 micron and 10 microns in thickness and at an angle of less than 2 degrees to the surface of the sheet material. The lamellµ may be 8-shaped in cross-section transverse to the length direction of the sheet material. The lamellµ may be J-shaped in cross-section along the length direction of the sheet material. The sheet material may comprise at least one further extrudable material interspersed with the lamellµ of the first and second materials and may be an adhesive bonding the first and second materials together. The second material may be polymeric and the adhesive may comprise a mixture of the principal polymeric components of the first and second polymeric materials. The second material may be a powder of inorganic material. The first material may be polyethylene and the second material cellular polystyrene, the two materials being united through interposed lamellµ of an adhesive material. The sheet material of the invention may be made by melt extruding the first and second materials through an annular die such as that shown diagrammatically in perspective view, partly in section, in Fig. 4 of the drawings. The device shown in Fig. 4 comprises an annular row of feed slots 3 for the first material alternating with an annular row of feed slots 4 for the second material above which is an annular collecting chamber having walls 5 and 6 which converge to an annular extrusion slot. The walls 5 and 6 may be rotated together relatively to the row of feed slots 3 and 4 whereby the drag exerted by the bottom of the collecting chamber on the lamellµ formed by the simultaneous feeding of the melts 1 and 2 through the slots 3 and 4 into the collecting chamber, the passage of the melts through the latter and their simultaneous extrusion through the annular slot at the top of the collecting chamber produces a shearing effect. The tube or tubular film of the laminated first and second materials thereby produced has the lamellar structure imparted to it which is characteristic of the sheet material of the invention. The melt extruded sheet material is cooled and solidified in the usual manner and thereafter may be longitudinally slit to the " lay flat form ". |
