| 摘要 |
PROBLEM TO BE SOLVED: To effectively shorten a vulcanizing time and effectively prevent a rubber from scorching or the like in the midway of its flow by a method wherein the diameter at a position, at which the diameter of a flow passage starts to reduce itself towards an injection hole in the flow passage between the pot of an injection molder to the injection hole at the tip part of the injection nozzle, is set to have a specified value. SOLUTION: A diameter D, which is uniform over a total length of a rubber flow passage 6 ranging from a pot 2 to the injection hole 4a at the tip part of an injection nozzle 4 including a diametral reduction starting point is set to satisfy an inequality: D>=(Q/100π)<1/2> (cm), in which, D (cm) is the diameter of the flow passage at the flow passage reduction starting point and Q (cm<3> ) is an injection volume. The vulcanization in the midway of the flow passage between the injection nozzle and a molding cavity is prevented from developing. The effective prevention of the development of scorching in the flow passage 6 is realized in conjection with the average flow rate at the diametral reduction starting point and the rubber temperature rise due to the heat development by shearing. In addition, the prevention of the development of the vulcanization in the midway of the flow passage between the injection nozzle and a molding cavity is realized in conjection with the required vulcanization time and the completion time of the filling of a rubber in a molding cavity.
|
