Appeal No. 95-3536
Application 08/038,400
feeding the polyolefin to be reclaimed into an extruder through a hopper, heating the polyolefin above
its melting point but below the melting point of the impurities in the polyolefin, and extruding the
melted material through a filter or a filter pack to remove the impurities (col. 1, lines 42-46; col. 2,
lines 40-60). Appellant further admits that phosphites are “known stabilization additives for
polyolefins” (specification: p. 1, lines 19-24). Minagawa and Moore disclose adding a bis(2,4-di-tert-
butylphenyl)pentaerythroitol diphosphite stabilizer to inhibit the degradation of polyolefins
(Minagawa: Cols. 21 and 22, Control 3; Moore: Examples 12-16). Minagawa discloses adding
bis(2,4-di-tertiary-butyl phenyl) pentaerythritol diphosphite to polyisoprene (Table I, col. 22) and
Minagawa teaches that the stabilized polyolefins compositions can shaped by extrusion or injection
molding or fiber-forming operations (col. 21, lines 44-46). However, we fail to find that the prior
art discloses or suggests a stabilized polyolefin composition which includes at least one epoxidized
ester of a fatty acid.
Minagawa’s invention is directed to adding bis(2,6-di-tertiarybutylphenyl) pentaerythritol
disphosphites to polymers such as polyolefins and polyvinyl chloride (PVC) to enhance the stability
of the polymer (col. 8, lines 66-68; col. 20, lines 3-8). In discussing the (PVC) compositions,
Minagawa discloses that conventional plasticizers can be combined with the diphosphite and PVC
(col. 18, lines 31-41). Among the plasticizers listed is epoxidized soybean oil, appellant’s preferred
epoxidized ester of a fatty acid. In a separate discussion for compositions comprising the diphospite
stabilizer and polyolefins, Minagawa broadly teaches that other conventional additives such as
plasticizers can be added to the stabilized polyolefin (col. 21, lines 30-33), but does not give an
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