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645,688. Moulding containers and their covers. BRITISH CELANESE, Ltd. June 18, 1946, No. 18309. Convention date, June 19, 1945. [Class 87 (ii)] In a process for moulding a container or a cap therefor of thermoplastic material (suitable, e.g. for containing face-powder), the open end of a hollow cylindrical blank is pressed into an annular channel in a die, the walls of which channel are axially inclined, so that the side wall of the blank near the open end is given a truncated conical form and is turned upon itself to form a bead. The apparatus shown comprises a rotatable spindle 3 which can be raised or lowered, and which carries a holder 8 for receiving a preformed cylindrical body 9 that is to form a container. The bottom of the body 9 rests upon an annular pad 14, preferably of rubber, which is in contact with a locating block 13, of such thickness that the end of the body 9 protrudes to an appropriate extent when inserted in the holder 8. The parts 8, 13 are preferably of low heat-conducting material. A die for shaping and for beading the edge_of the mouth of the container consists of a plate 16 having an annular channel 17 with sloping walls, as shown. The plate 16, which is mounted on an electrical heating unit 23, is aligned with the holder 8, so that when the holder is lowered as the spindle 3 rotates, until the edge of the container body is pressed down against the inclined side 18 of the channel 17, the heated die-plate tapers the end 22 of the body into a truncated conical formation, and a bead 21 is formed on the edge. A similar method is used for making a cover for the container, which cover is adapted to fit tightly on the body of the container. For this purpose, a die 28 as shown in Fig. 2 may be used for producing from a preformed cylindrical blank a cover 31 having a wall which tapers slightly inwardly and has a beaded edge. The container bodies and covers to which the forming process is applicable may be made of cellulose derivatives, synthetic resins, or other thermoplastic material. Specification 645,687 is referred to.
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