| 摘要 |
<p>Impact resistant and flame retardant polymer composition, slab-like rectangular solid made of said composition, and composite laminate article having at least one layer of said composition. Composition is preferentially compression molded using a blended particulate feed of relatively high bulk. The polymer composition comprises a maximum of 86 volume percent of ultra high molecular weight polyethylene (UHMWPE), a minimum of 8 volume percent of a flame retardant additive or mixture thereof, and a minimum of 6 volume percent of chopped reinforcing fibers, all volumes referring to the densified (molded) state. In addition the bulk volume of the chopped reinforcing fibers, as measured by a tapped density test, must be a minimum of 27 percent of the final molded volume of the composition (BVPF equal to or greater than 27). The maximum volume % loading of the additives is limited by the requirement that the notched Izod impact strength is a minimum of 7 ft.-lb per inch width. The preferred flame retardant additive is essentially a water insoluble form of ammonium polyphosphate having a water solubility not exceeding 1 gram per 100 grams of water, and the preferred reinforcing fibers are chopped glass fibers about 1/8 to 1/4" inch in length. A significant flame retardant improvement without sacrifice in impact strength is achieved if a thin compressible non-woven fiberglass veil is applied to the top of the particulate feed prior to molding the slab-like solid. The composite layer has first and third layers of essentially rigid compounded high molecular polymers above described, and a second or middle elastomer layer, which is also preferentially flame retarded.</p> |
