| 摘要 |
PURPOSE:To prevent the crack due to the change of using environment, relaxing the concentration of tensile residual stress by heat-treating the resin molded product provided with the embedded article 6 having different thermal expansion coefficient from the resin in a cast resin 10. CONSTITUTION:Several cycles (at least three cycles) of heat treatment are applied to the resin molded product provided with the embedded article 6 having different thermal expansion coefficient from the resin in a cast resin 10, at the specified temperature range wider than used temperature range, e.g. at the temperature range from -15 deg.C to the temperature higher than the glass transition point (secondary transition point) of the cast resin by 40 deg.C. At the stage of temperature lowering of the first and second cycles, the thermal hysteresis showing that the tensile residual stress in the cast resin at the periphery of the embedded article is remarkably reduced (about 0.1-0.25kg/mm.<2>) is observed. At the stage of the third cycle, the deviation of the thermal stress becomes normal, and the hysteresis phenomenon doesn't almost occur, whereby the tensile residual stress in the cast resin at the periphery of the embedded article may be reduced and relaxed. |
