Appeal 2007-1169
Application 09/850,857
1. A composite panel, comprising:
an inner impact modified polymer layer and an outer
impact modified polymer layer both formed of a rigid plastic,
each of said layers having a uniform thickness between 0.004
inches and 0.020 inches, each of said inner and outer polymer
layers comprising a polyvinyl chloride polymer formulation
with a specific gravity range from 1.35 to 1.50, and wherein
each of said inner and outer polymer layers contains from 2.0 to
8.0 parts per hundred parts of an impact modifier;
a center layer selected from the group consisting of
calcium carbonate filled polyvinyl chloride, foamed polyvinyl
chloride, and foamed and calcium carbonate filled polyvinyl
chloride, said center layer being coextruded by extrusion
through a multi-manifold die so as to be fused to said inner and
outer polymer layers, said inner and outer and center layers
being formed together in a molten, liquid state which produces
one compact unit of three layers, said center layer having a
specific gravity ranging from 0.80 to 1.60 and having thickness
ranging from 0.015 inches to 0.040 inches, and wherein said
center layer is further characterized by the substantial absence
of impact modifier;
said composite panel having a thickness between 0.035
inches and 0.060 inches; and
said composite panel having an impact resistance of 60
in. lbf. as measured in accordance with ASTM Standard D-
3679-96.
Independent claim 6 is similar to claim 1 but requires a high heat distortion
triwall panel where the center layer is a chlorinated PVC. (Br 20).
Independent claim 7 differs from claim 1 in that claim 7 requires a triwall
panel that has improved impact strength and is suitable for use in cold
climates. (Br 19). Independent claim 8 is similar to the other independent
claims but requires that the center panel be made of regrind or recycled type
materials. (Br 20-21).
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