| 摘要 |
PURPOSE:To prevent the generation of the irregularity in the tensile strength of the warp and weft yarn of a synthetic resin net and to uniformize the thickness of said yarns, by setting the water temp. of the upper layer part in a water tank to the stretching temp. region of a synthetic resin material while setting that of the lower layer part in said tank to temp. lower than that of the upper layer part and completing the stretching process of the synthetic resin material during the passage of said material through the upper layer part. CONSTITUTION:Temp. difference is applied between the upper and lower layers of the water in a water tank and the water temp. t1 of the upper layer part is set to the stretching temp. region of a synthetic resin material and the water temp. t2 of the lower layer part is set to temp. lower than the stretching temp. region. In this state, the synthetic resin material 2 in a plastic state extruded from a die 1 is guided to the above mentioned water tank to complete the stretching process of the synthetic resin material during the passage of the synthetic resin material through the upper layer. By this method, since uniform cooling is performed to the synthetic resin material whose stretching process is completed in the stretching temp. region, a molded product uniformized in mechanical strength such as tensile strength at every part is obtained and, especially, in the preparation of a synthetic resin net, a molded product uniform in the thickness of every part of warp or weft yarn and excellent in mechanical strength such as tensile strength is obtained. |
