MANUFACTURE OF BIAXIALLY ORIENTED POLYPROPYLENE BOTTLE

摘要

PURPOSE:To manufacture a bottle superior in its transparence, rigidity, impulse strength and interrupting peculiarity of gas, by investigating a property of matter and blow terms of a material for manufacture of a biaxially oriented bottle by making injection blow of polypropylene. CONSTITUTION:A bottomed parison is formed by injection molding of polypropylene whose standard melting tension is 1.5-6g and a difference between the melting point and a crystallizing temperature is more than 43 deg.C. Biaxially oriented blow molding is done by taking out said parison from an extrusion molding metallic die while the parison is not cooled completely. A molding temperature is set so that a resin temperature of a shell part of the bottomed parison becomes 100-165 deg.C. As an opening of a bottle is a matter held by a metallic die the foregoing temperature is not applicable to the opening.