| 摘要 |
<p>PURPOSE:To ensure a uniform expansion and a firm fusion by a method wherein styrene resins having different compositions are separately melted and loaded with a foaming agent, the styrene resins are separately charged into a die to be molded into a columnar or cylindrical shape, allowed to be confluent with each other, and foamed as a laminate, and the inner surfaces of the resins are fused to each other before the softened inner surfaces are set. CONSTITUTION:Styrene resins having different compositions are separately melted in extruders 1 and 2, loaded with a foaming agent, kneaded, cooled, and introduced to introducing ports 32, 31 of an adapter 21. The both are allowed to be confluent with each other at the outlet of the adapter, fed into a die 22, brought into collision with a torpedo 221, formed into a two-layer cylindrical shape, and extruded from an orifice at the outlet of the die as a laminate. Air is jetted out of an air ring 222 onto the surface layer thereof. The tubular material is passed through guide rolls, pressed flat by pinch rolls 41, and cut into a planar foam while being taken off by a take-off device. As a result, a skin having a low expansion ratio is not produced at the interface of the layers, and the layers are firmly fused to each other at the interface thereof.</p> |
