ANALYTICAL METHOD OF RESIN FLOW STATE IN SYNTHETIC RESIN MOLDED ITEM

摘要

PURPOSE:To reproduce the dynamic behavior of resin in a cavity in the form of its cracks by a method wherein a molded item, which is molded out of molding material mainly composed of polyolefin, is heated up to a temperature ranging from 100 deg.C to less than the melting point of the molding material in the presence of oxygen. CONSTITUTION:Deterioration by heating is produced by heating a molded item, which is molded out of molding material of polyolefin. The heating temperature must be 100 deg.C or higher and is preferably as high as possible for the production of the desired deterioration in a short time and at the same time must be below the melting point of the molding material. Since the melting point of polyolefin varies within the range of about 160-165 deg.C depending on its grads. The optimum heating temperature is about 150 deg.C. Polyolefin molecules are cut by the action of heat and oxygen, resulting in cracking. The cracks extend normal to the flow of the resin in a cavity in the form of fringes.