HEAT-SHRINKABLE FILM FOR LABEL HAVING LOW SPECIFIC GRAVITY AND METHOD FOR MANUFACTURING SAME

摘要

A heat-shrinkable film for a label according to the present invention consists of: a foamed layer (10) having polystyrene as a main component; and one pair of non-foamed layers (20) which are melt-adhered to the foamed layer (10) on either side thereof, wherein the foamed layer (10) and the one pair of non-foamed layers (20) are formed by coextrusion and thus have a low specific gravity of less than 1.0. The heat-shrinkable film for a label according to the present invention is manufactured by: producing an unstretched film by coextruding each of the raw materials so that non-foamed layers (20) are formed on either side of a foamed intermediate layer (10) having polystyrene as a main component; and stretching the unstretched film in the transverse direction (TD). The stretching in the TD is preferably 3.5 to 5.5 times, and most preferably about 4.5 times. The foamed layer (10) is preferably foamed at a foaming rate in the range of 5% to 20%. The thickness of the foamed layer (10) is preferably in the range of 60% to 90% with respect to the total film thickness, and the thickness of each of the one pair of non-foamed layers (20) is preferably in the range of 5% to 20% with respect to the total film thickness. The heat-shrinkable film for a label according to the present invention preferably has a thickness in the range of 30 µm to 60 µm.