GB1169701A - Improvements in or relating to Packaging Material - Google Patents

Abstract

1,169,701. Corrugated fibreboard. MACMILLAN BLOEDEL CONTAINERS Ltd. 2 Nov., 1966 [2 Nov., 1965], No. 46307/65. Heading B5N. A process for the production of corrugated fibre board packaging material consisting of corrugated sheeting 1 having a liner 2 and/or 3 consisting of a plain sheet adhesively secured to one or both sides thereof, the corrugations on at least one side containing a foamed plastics substance, e.g. polystyrene or polyurethane, either as a coating or filling comprises the steps of feeding a foamable plastics substance in the form of beads or discrete particles so as to enter the flutes on one side of the corrugated sheeting applying a liner to said one side of the corrugated sheeting either prior to, after, or at the same time as the entry of the foamable plastics substance into the flutes and passing the material through a heating zone to effect curing of the foamable plastics substance to produce in the flutes a coating or filling of foamed plastics substance. In one embodiment of apparatus for carrying out the process, Fig. 3, material comprising corrugated sheeting 1 and liner 3 is fed beneath a hopper 6 from which a plastics substance in solid form is fed under gravity into the flutes of the sheeting 1. The material passes via wiper roller 7 to a heater 9 where the plastics substance is cured and then into contact with a liner 2 between driven bands 11, 12. When the plastics substance is not adhesive the liner 2 is coated with adhesive by rollers 13, 16, 17. The liner 2 may be applied prior to passage of the material through the heating zone. Instead of using the hopper 6 a solid plastics substance may be fed into the flutes from a nozzle under pressure. In another embodiment (Fig. 8, not shown) material comprising an apertured liner and a corrugated sheet is fed liner uppermost beneath a hopper and a plastics substance from the hopper enters the flutes of the corrugated sheet via the apertures in the liner. The lower tips of the corrugated sheet are coated with adhesive and a second liner is fed into contact therewith prior to the material entering the heating zone. In a further embodiment (Fig. 10, not shown) material comprising a corrugated sheet and an upper liner has the lower tips of the corrugated sheet coated with adhesive and a lower liner fed into contact therewith prior to the material entering the heating zone. The lower exposed flutes of the corrugated sheet are filled with a plastics substance applied under pressure from a nozzle immediately prior to application of the lower liner. In further embodiments corrugating rolls at which the corrugated sheet is produced from plain sheet are included in the apparatus. In one of these embodiments (Fig. 5, not shown) the corrugated sheet from the rolls passes beneath a hopper where its uppermost flutes are part filled with a plastics substance, has a liner applied to its uppermost surface before passing through a heating zone, is inverted by passage about a reversing roller, has its now uppermost flutes part filled with a plastics substance from a second hopper, and has another liner applied thereto before passing through a second heating zone. In another of said embodiments the corrugated sheet is fed into contact in the nip between one of the corrugating rollers and a plain roller with a liner which has been covered with a plastics substance. A liner is applied to the opposite face of the corrugated sheet before passing through a heating zone.