| 摘要 |
The present invention relates to a method and apparatus for forming an extruded plastic lumbar product from a commingled plastic waste feed stock. The apparatus generally includes an extruder portion and a forming portion. The extruder portion includes a compound extruder which compresses and melts the waste product by a sudden transition within a constant pitch conveyor. From the compound extruder, the melt is introduced into a hot melt extruder which is formed so as to prevent vortex of the melt or mixing of the different resins. The hot melt conveyor includes a diminishing pitch along its length and a short transition section and metering section. The hot melt is then formed into a desired profile through a cross-head die in which a series of rovings are introduced into the melt. The rovings serve as a reinforcement for the extruded product as well as define the extruded profile feed rate. Because of commingled blend of dissimilar resins in the feed material, there are often inconsistencies in the melt strength. The rovings compensate for these inconsistencies and provide an extruded product having the desired strength and stiffness characteristics. |
