| 摘要 |
PURPOSE:To elevate the folding strength of a joint surface by molding a first resin molding having first and second steps and a groove on the boundary with a protruded stripe on the back thereof to join a second resin molding with the second step thereof by an injection molding. CONSTITUTION:After a part of a die put tight into a space 19, a plastic 7 of color A thermally plasticized is forced thereinto. Thereafter, when the plastic of color A is cooled and solidified, a part of the die 19 is pulled out and a plastic of color B thermally plasticized forced thereinto. Because of the plasticization of the plastic of color B, the contact surface with the plastic 7 of color A, namely, the end 15 and the second step surface 14 thereof is softened to join the plastic 7 of color A and the plastic 8 of color B. This enabling the joining of plastics of two colors on two sides thereby providing a higher folding strength. |
