| 摘要 |
<p>Appts. for producing a co-extruded plastics decorative strip, suitable for automotive trim, consists of a co-extrusion die in which a decorative layer is extruded on the upper surface of a base strip. The decorative layer is extruded in a thickness which is constant along the extrusion length but which varies across its width, thus producing a decorative variation of colour intensity. The thickness variation is produced by the die profile aided by a flow restrictor dam in the coloured material flow path. - A generally conventional thermoplastics co-extrusion die is fed by a first extruder to produce a base strip (11), typically of PVC or polyolefin, which may opt. be recycled material. The strip proceeds in the soft state to a directly communicating die (31) where a second extruder feeds a coloured like material through a channel (38) to a feed chamber (40), consisting of an upper and lower passage (42, 43), sepd. by a flow restrictor dam (44) whose surface is spaced pref. by 0.4 mm from the die plate thus allowing a small flow of coloured material from the upper to the lower passage. The dam (44) is bypassed by first and second feed channels (48, 49) through which the major flow occurs. In co-operation with a suitably shaped die plate, a layer of coloured plastic of variable thickness is co-extruded on the surface of the still soft base strip (11) and around its edges (15, 16) where it melt bonds. The strip proceeds conventionally to takeoff and cooling. In other embodiments, various surface profiles are envisaged for the strip.</p> |
