| 摘要 |
There is disclosed a process for the continuous production of a thermoplastic product having oriented components. The thermoplastic compound may include filler. Preferably the filler material is characterized by high aspect ratios (length to diameter). The filler may be an inorganic filler such as mica and talc flakes, glass and carbon short fibers or organic cellulosic materials derived from wood/forest by-products and agricultural by-products. Plastics such as polyolefins, vinyls, styrenics, polyesters and polycarbonates may be used. The process may be used to manufacture both integral foam products and substantially solid products of various shapes which may have flexural/bending strength and modulus 2-10 times higher than conventionally produced products made of the same plastic/polymer material (foamed and unfoamed). The product produced by the process may have filler concentrations as high as 75 percent. The product is made by an extrusion process which orients the thermoplastic polymer and the filler, when present, in the longitudinal direction during extrusion, and which prevents relaxation of the thermoplastic polymer thereby substantially preserving the imparted orientation. With respect to the integral foamed core embodiment, the die assembly is designed to facilitate orientation of polymer molecules and filler particles, when present, in order to produce an oriented skin; to form a cavity in the thermoplastic compound; to foam thermoplastic compound into the cavity due to the action of a foaming agent; and to cool the thermoplastic compound to form an integrally foamed product. |
