GB1265547A - - Google Patents

Abstract

1,265,547. Packaging particulate or pulverulent material. BADISCHE ANILIN- & SODAFABRIK A.G. 13 June, 1969 [15 June, 1968; 27 Sept., 1968; 5 Dec., 1968], No. 30104/69. Heading B8C. In a process for packing particulate or pulverulent products in packaging made of plastics sheeting, a container made of orientated plastics sheeting provided with perforations having a diameter less than the mean particle size of the product, is filled with the product, is cleaned after filling and is then heated until the perforations have closed. As shown, the sheeting 2 is drawn in tubular form from a roll 1, across a table 4 and below a roller 5 provided with needles for perforating the sheeting prior to the latter passing into a unit 7 where it is cut into sections and made into bags. The empty bags are -then conveyed to .bag-filling equipment 10 and after filling, are conveyed beneath a cleaning device 15 comprising revolving brushes 16 or compressed air before passing through a heating zone 18 e.g., an oven, which releases directional and frozen-in stresses set up during the perforation process and causes the perforations to close and the filled containers to assume a compact shape. Cooling means 20 may be provided downstream of the heating zone 18. In another arrangement, Fig. 2 (not shown), non-tubular sheeting is used which is drawn over a roller below the roller 5 and the containers may be heated by a heated endless belt and the cooling of the filled containers effected by cold air or by water-cooled plates. The Specification describes experiments to determine (a) the heating times required to close the perforations in sheeting of thicknesses between 0.10 mm. and 0.25 mm. for temperatures in the range 120‹-200‹ C.; and (b) the residual porosity of sheeting of thicknesses between 0.15 mm. and 0.25 mm. for heating periods of 3-8 seconds. A polymer dispersion or solution may be applied to the filled containers by brushing or spraying and wiping before or during the heating period. Internal pressure on the sheeting caused by the product may be relieved during the heating period by supporting the sides of the container against belts running on rollers arranged perpendicularly to a conveyer (2) or by supporting the edges of the conveyer (2) so that the conveyer forms a trough, Figs. 5 and 6 (not shown).