| 摘要 |
PURPOSE:To make it possible to make the density and hardness of a molded item at its surface different from those at its interior by a method wherein two raw material injection ports, through which one of two resin components reacting with each other is injected, are provided so that the two injection directions intersect each other and, in addition, a cleaning shaft can be held at two positions or at one position, at which both the injection ports open, and the other position, at which only one injection port opens. CONSTITUTION:When a cleaning shaft 23 is held at a position in which only one of two injection ports 28 and 29 is open to a mixing chamber 22, by shifting the cleaning shaft 23 during one injection, only one polyol is injected. Further, when the shaft 23 is held at a position, in which both the injection ports 28 and 29 are open, both polyols are injection so as to be collided against and mixed with isocyanate (or isocyanates) which is (or are) injected through the other injection port 30 (or ports 30 and 31) nearly on the center line of the mixing chamber 22, By realizing the period in which only one polyol is injected, and the period in which both the polyols are injected, the density, hardness and the like, for example, of a molded item at its surface can be made different from those at its interior, as required. |
