| 摘要 |
PROBLEM TO BE SOLVED: To efficiently clean a screw without detaching the same by cleaning a cylinder and a screw by using a rubber powder formed from a waste rubber tire as a purging material at a time when the injection, molding of a phenol resin molding material of which the melt viscosity at a specific temp. is a specific value or less is completed. SOLUTION: A phenol resin molding material of which the melt viscosity at 100 deg. is 101 Pa-s or less is low in viscosity in a state plasticized and melted at 90-1251 deg. and has tackiness. However, since a waste tire rubber powder is not melted at 90-125 deg.C but relatively low in its elastic modulus, it has flowability under the high pressure and high shearing force in a cylinder. Therefore, the rubber powder enters a narrow region like the gap between a screw and the cylinder and the remaining molding material can be extruded as elastic particles of the rubber powder. Since the molding material has no tackiness within this temp. region, if the screw is detached after purging, the rubber powder can be easily removed. |
