Appeal No. 1999-2488
Application No. 08/841,027
The subject matter on appeal relates to a method for
improving heat/humidity aging resistance of a flame retardant
thermoplastic composition. Further details of this appealed
subject matter are set forth in representative independent claim
9 which reads as follows:
9. A method for improving heat/humidity aging resistance of
a flame retardant thermoplastic composition, comprising the
steps of:
(a) providing an aromatic polycarbonate resin
present at a level of from 60 to 90 percent by
weight based on the total weight of the
composition,
(b) providing a vinyl aromatic-unsaturated nitrile-
diene rubber graft copolymer present at a
level of from 8 to 15 percent by weight based
on the total weight of the composition,
(c) providing a vinyl aromatic-unsaturated nitrile
rigid resin present at a level of from 1 to 10
percent by weight based on the total weight of
the composition,
(d) providing a phosphate present at a level of from
3 to 15 percent by weight based on the total
weight of the composition; and
(e) providing a tetrafluoroethylene polymer present
at a level of from 0.05 to 2.0 percent by weight
based on the total weight of the composition,
wherein said diene rubber of said graft copolymer
is present at a level of from 6 to 12 percent by
weight based on the total weight of the
composition whereby said composition retains
about 80% of the original Izod impact strength
after one week aging at 63 oC at 100% relative
humidity.
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