BINDING MATERIALS HAVING GOOD TEXTURE AND HIGH IMPACT RESISTANCE

摘要

1452421 Foamed polypropylene articles SUMITOMO CHEMICAL CO Ltd and TOYO CLOTH CO Ltd 9 Jan 1974 [9 Jan 1973] 1083/74 Heading B5A [Also in Division C3] A mixture of crystalline and non-crystalline propylene polymer and optionally low density polyethylene together with azodicarbonamide is extruded from die 5 (see Fig. 4) and the molten foamed sheet is embossed by embossing rolls 6 and the cooled solidified sheet is then passed through a finishing roll 7. The foamed embossed sheet is pressed on one or both sides with heated metallic moulds to form grooves (see Figs. 1 and 2) which act as hinge portions when these sheets are used as book covers (Fig. 6) and files.