Abstract: A polypropylene film which is capable of suppressing blocking in a rolled polypropylene film. The polypropylene film has a first surface and a second surface, contains a polypropylene resin as a main component, and is configured such that: the Svk value (SvkA) of the first surface is 0.005 ?m or more and 0.030 ?m or less; the Spk value (SpkA) of the first surface is more than 0.035 ?m and 0.080 ?m or less; the Svk value (SvkB) of the second surface is 0.005 ?m or more and 0.030 ?m or less; and the Spk value (SpkB) of the second surface is 0.015 ?m or more and 0.035 ?m or less.

Abstract: A process whereby artificial rawhide comparable in qualities to natural rawhide can be produced. After pre-treatments such as washing with water, liming, bleaching, etc., rawhide is roughly cut into pieces (about 10 cm×10 cm) and then further finely cut with the use of a chopper and a micro-cutter to thereby prepare collagen fibers. Next, water, a collagen fiber powder and gelatin are added thereto to give a sol or a gel having a moisture content of 60 wt % to 80 wt %. Then it is extruded into a sheet, using a screw extruder at 30° C. or below and dried, thereby giving artificial rawhide. This artificial rawhide in the form of a sheet is cut into strips in a predetermined size. Then, each strip is rolled in the width direction and tied in the length direction. Thus, a bone-shape chewing gum for dogs can be obtained.