| 摘要 |
PURPOSE:To increase the productivity of plastic cases for watches of which strength and measurement accuracy are improved by mixing specific glass fibers with casting synthetic resin which is hardened by ultraviolet irradiation to use prepared elastic transparent synthetic rubber as a molding material. CONSTITUTION:Glass fiber-mixed synthetic resin obtained by mixing 60wt% <= glass fiber treated by acrylic silane of which length is 10mu>= and aspect ratio is 10>= with ultraviolet-hardened casting synthetic resin such as spiran resin to which photopolimerization starting agent (benzophenone, etc.) is added and removing babbles is cast into elastic synthetic rubber molds 3, 3' prepared by using transparent liquid type silicone rubber or the like, the molds are fixed by upper and lower glass plates 7 and then 50W/cm>= ultraviolet rays is ir- radiated for about 30sec after irradiating 10W/cm<= for about 30min. Thus the complicatedly shaped case 5 with strong bending strength can be precisely produced for a short time under the reduced number of processes in comparison with the conventional method. |
