POLYPROPYLENE COMPOSITION FOR DISK CARTRIDGE AND DISK CARTRIDGE

摘要

PURPOSE:To provide the disk cartridge having a shutter which does not generate worn powder in a cartridge case in spite of repetitive sliding of several tens thousand times and has excellent mechanical strength, etc. CONSTITUTION:The disk cartridge has the cartridge case 1 having a head insertion hole 3, a disk-shaped recording medium housed rotatably in the cartridge case 1 and the shutter 4 which opens and closes the head insertion hole 3 of the cartridge case 1. A compsn. contg. a polypropylene resin compsn. consisting of polypropylene and diorganopolysiloxane is used for the material of this shutter 4.