TRANSPARENT SHRINKABLE FILM USING MIXTURE OF POLYPROPYLENE AND HYDROCARBON RESIN AS BASIS AND MANUFACTURE THEREOF

摘要

PURPOSE: To provide a film which can be used for a sleeve and has superior optical properties and also outstanding mechanical characteristics by forming a heat-sealable upper layer containing a mixture with low sealing properties of a polymer obtained from -olefin on the two surfaces of a base layer. CONSTITUTION: This transparent and shrinkable film comprises a base layer containing 60-95 wt.% of a polypropylenic polymer and 5-40 wt.% of a hydrogenated hydrocarbon resin with a softening point falling within the range of 80-125 deg.C, and also a heat-sealable upper layer laminated on the two surfaces of the base layer. The heat-sealable upper layer is made up of a sealable olefinic polymer. The appropriate olefinic polymer is a mixture with low sealing properties of a homopolymer, a copolymer or a terpolymer obtained from -olefin with 2-4 carbon atoms. The olefinic polymer used for the heat-sealable upper layer has a lower melt point than does the propylenic polymer of the base layer. The film shows a significantly high shrinkability in the transverse direction even at a comparatively lower temperature (90 deg.C) and also remarkably desirable mechanical characteristics.