| 摘要 |
1441228 Egg cartons MOBIL OIL CORP 25 Nov 1974 [26 Dec 1973 4 Feb 1974] 50938/74 Heading B8P [Also in Divisions B4-B5 and C3] An egg carton is thermoformed from an extruded foamed polystyrene sheet which has. been extruded with respective thicker and thinner portions 15, 16, Fig. 1B, extending longitudinally of the sheet for respective thermoforming to the egg receiving cavity portion 17 and the cover portion of the carton 18. The thicker portions 15 are extruded with a lower density, but are deeper drawn by thermoforming to form the cavity portion having a higher weight per unit area than the cover portion. In the Fig. 1A and 1B embodiment, the extrusion die outlet configuration of Fig. 1A produces a tubular extrudate having a pair each of thick and thin portions, and which is split by two knives into a pair of sheets, each having the Fig. 1B configurator comprising thick and thin portions 15, 16 and which is thermoformed to a pair of cavity and cover portions 17, 18 which are cut at C-C<SP>1</SP> into a pair of cartons. The thickness, weight, and density across an extruded sheet and formed carton is stated, and side and end crush resistances, and cell crush resistances, and the weight ratio of cavity to cover sections are stated in comparison with cartons made from uniform thickness sheet. |
