| 摘要 |
1485504 Blow-moulding OWENS-ILLINOIS Inc 1 Nov 1974 [2 Nov 1973] 47361/74 Heading B5A In a blow-moulding process, a thermoplastic preform is enclosed in a blow-mould, a part of the mould cavity of which is defined by a movable portion, and blow-moulded therein, the movable portion is removed and replaced by a second movable portion of different configuration, the part of the article formed against the first movable portion then being reformed by contact with the second movable portion while this part of the article is at a temperature conducive to molecular orientation. The preform may be injection moulded or formed by the preliminary blow-moulding of an extruded tube. As shown in Fig. 4, an extruded tube 15 is enclosed by preliminary blow-mould halves 19a, 19b, forming tail flash 31 which is removable by axially movable members 20a, 20b and blow-mandrel 22 is introduced, forming neck threads 12 by compression against the mould parts. Pin 24 is lowered to supply blowing air through duct 26 to blow-mould the parison into preform 32. Surplus interior material 30 is flattened by lowering of cap 25 on pin 24. Blowing air is then exhausted along groove 27 of pin 24, and port 28. Blow mandrel 22 is then replaced by final blow mandrel 36, Fig. 6, and the preform 32 transferred to the final blow-mould 40. The final blow-mould 40 comprises halves 40a, 40b, one of which 40a has a semicircular recess, the other 40b having a mating semicircular projection 53 having a circular cylindrical hole, across which is laterally movable a first, flat, bottom-defining member 43 and in which is a vertically movable, domed, second bottom-defining member 45. The mould halves 40a, 40b close on the preform 32, with first bottom member 43 in position. Pin 38 of mandrel 36 is then extended to stretch the preform until it contacts bottom-defining member 43 and the preform is blow-moulded to form a flat-bottomed article (Fig. 8, not shown). Bottom member 43 is removed and bottom member 45 moved up to deform the article bottom (Fig. 9, not shown). In the embodiment of Figs. 11-15 (not shown), cap (64) of blow mandrel (61) is extended, slightly stretching the preform, which is then blow-moulded. Bottom 43 is removed and member 45 extended, mechanically stretching the flat article bottom until it contacts the concave base (66) of cap (64) forming a sealed chamber, the bottom then being further deformed by air supplied through duct (59) of cap (45). Cooling may be effected by further blowing air or by cooled bottom parts 43 and/or 45. The blow mandrels may be rotated. |
