Method of preparing shaped articles from high molecular weight highly crystalline polypropylene

摘要

Shaped articles of polypropylene are formed by compressing powdered highly crystalline polypropylene in a mould at 200 kg. per square cm. pressure either at a temperature of 150 DEG to 200 DEG C. so as to form a completely coherent mass, or at a temperature below 170 DEG C. to form a partly coherent mass which is rendered fully coherent after withdrawing it from the mould and heating it to 170 DEG to 190 DEG C. in a liquid or gaseous medium. The polypropylene preferably has a molecular weight of at least 1,000,000.