PROCEDURE FOR THE MANUFACTURING OF BIAXALLY ORIENTED, FORM-LAST ARTICLES AND APPARATUS

摘要

1373451 Blow-moulding; orientation OWENS-ILLINOIS Inc 4 Jan 1972 [4 Jan 1971] 298/72 Heading B5A Blow-moulded articles are formed by downwardly extruding a plastics tube, closing a preform mould on to it and separating the enclosed portion from the orifice, moving the mould and enclosed tube to a first blowing station and blow-moulding the tube to a preform, transferring the preform to a final blow-mould, and blow-moulding the preform therein. The final blow-mould preferably has an average wall temperature for a crystalline polymer between the crystalline melting point +20‹ F. and the crystalline freezing point -20‹ F. or for an amorphous polymer at the glass transition temperature Œ25‹ F. for forming biaxially oriented articles. As shown in Fig. 4, the apparatus comprises an extruder 21 to extrude parison 22, preform blow-moulds 35 and final blow-moulds 36 mounted on platens movable diagonally by cylinder 28, blow tubes 46, 48 moved by cylinders 45 on blow tube plate 41 which carries a stripper plate 47 and is moved by cylinder 43. In the position of the lefthand side of Fig. 4, tube 22 is enclosed by preform mould 35 and severed by knife 49, while the blown preform 50 is enclosed by final blow-mould 36 and the finished blown article 51 is held outside the blow-mould assembly 25. Blow tubes 46, 48 are then raised, stripping article 51 against plate 47. Assembly 25 is then moved downwardly to the left. Blow tubes 46, 48 are lowered to blow-mould the tube 22 to preform 50 and the preform 50 to another finished article 51. The assembly 25 is then opened and moved to the right and the cycle is repeated. The operations are timed between those of another assembly 25 at the right. Bottom waste is removed from the preform by pivoted inserts 39. The neck of the bottle has external screw-threads (62, Figs. 7-12, not shown), formed by compression between blowmould inserts (60) and blowing mandrel (70), the lip (77 or 96) being formed by sleeve (75).