METHOD FOR INJECTING PLASTIC RAW MATERIAL SOLUTION AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To fill a mold for molding plastic with a plastic raw material soln. without allowing the same to overflow by detecting the liquid level of the plastic raw material soln. in the mold for molding plastic by a back pressure type sensor to control the supply of the plastic raw material soln. SOLUTION: When the injection of a raw material soln. into a cavity is advanced and the liquid level of the raw material liquid reaches the tip of the nozzle 2 of the back pressure type sensor set to the liquid level of a full filling state, back pressure is generated in the nozzle 2 for the back pressure type sensor and a back pressure type sensor 5 detects the change of this back pressure to close an automatic valve 6 through a control means 11 and a slider 3 is drawn up by an up and down air cylinder 4. By this constitution, a raw material soln. injection nozzle 1 and the nozzle 2 for the back pressure type sensor 2 are drawn out of a mold 13.