METHOD OF AND APPARATUS FOR WRAPPING MATERIALS

1,231,352. Shrink-packaging. W. R. GRACE & CO. 21 April, 1970 [12 May, 1969], No. 24193/69. Heading B8C. A method of wrapping an irregularly-shaped article such as a round-ended loaf comprises providing an encompassing package of heatshrinkable film material about the article and using heat-shrinking plates 5, 6 which are shaped to conform with the article to be shrinktidied. As shown, a tube of perforated polypropylene film 1, 2 is formed around a roundended loaf and its flat ends are folded up by guiding slots (13), Fig. 6, not shown, as the loaf passes between plates 11, 11 on a baseplate 15 which seals a seam on the underside of the loaf. With the ends of the tube folded up, as indicated in Fig. 3, the loaf is moved by a conveyer belt 16, between a pair of vertical, horizontally-moving glass cloth belts 17, 171 which are backed respectively by heating elements 22, 221; 23, 231 and cooling elements 24, 241 to effect a heat-sealing of the folded up ends of the tube and a subsequent cooling. In order to tighten the loose sealed ends of the package the plates 5, 6 having respective arcuate heating faces 9, 10 are advanced over the ends of the loaf. The arcuate faces 9, 10 are coated with a polytetrafluoroethylene release agent. The loaf may be initially wrapped by moving it axially into an open-ended tube of film material, or by pulling a length of film material over a guide, clamping the free end of the material, placing a loaf in the film and moving it past the clamped end so that the latter comes into contact with the part of the web remote therefrom and forms a tubular passage, and severing the web adjacent a subsequently formed seal. To ensure that the light polypropylene film is passed across the various guide surfaces of the apparatus, curtains, or jets, of air may be directed over the surfaces.