GB1528847A - Process of blow moulding bottles - Google Patents

Abstract

1528847 Temperature conditioning of blow moulding preforms MONSANTO CO 12 March 1976 [13 March 1975] 9939/76 Heading B5A A blow-moulded thermoplastic material preform 50, Fig. 1, for blow moulding, e.g. after axial sketching, in the temperature range of molecular orientation, into an oriented carbonated beverage bottle, Fig. 3, comprises a neck portion 62, and a dependent body portion which is preconditioned to the temperature of molecular orientation by extracting heat from it, e.g. by convected air from panels 38, whilst simultaneously heating a region 16 adjacent the neck, e.g. by electric heaters 10, to establish a temperature difference between the region 16 and the remainder of the body, of between 1-5 and 11‹ C., to alter the amount of stretching which would otherwise occur during the blowing. The process produces a more even thickness between an upper reduced diameter portion 21 of the bottle and the remaining portion 20, including the base 22, 23, in which greater impact strength is required, and this may involve heating the region 16 to the higher temperature so that it stretches more, or else the remainder of the body may be additionally heated to eliminate double thickness folds in the region 23. The preconditioning is preferably effected during continuous sequential transport of a plurality of preforms, by sockets 56 of transporting pinions 64 which co-operate with worm sections of a shaft 74 to simultaneously rotate the preform about its axis.