Appeal 2007-4316
Application 09/911,268
B. Findings of Fact (FF)
The 268 Application
1. Application 09/911,268 ("268 Application") was filed on 23 July
2001, claiming the benefit under 35 U.S.C. § 119(a) of German application
100 36 057.2, filed 25 July 2000.
2. According to the inventors, polycarbonate compositions with
oligophosphates based on bisphenol A as flame retardant additives are well
known but suffer from increasing deterioration of mechanical properties and
yellowing under prolonged thermal stress. (268 Application at 1–2.)
3. The inventors disclosed that polycarbonate compositions comprising
oligophosphate compounds that contain less than 1 wt% of
isopropenylphenyl phosphate ("IPP") compared to the total phosphorus
compound employed exhibit and maintain good mechanical properties and
high heat resistance under prolonged thermal stress. (268 Application
at 2:18–26.)
4. According to the inventors, commercially available oligophosphates
based on bisphenol A contain IPP as an impurity due to breakdown during
synthesis, transportation, or storage, up to about 10 wt%. (268 Application
at 3:1-9.)
5. The inventors disclose that the IPP content may be kept low by
maintaining relatively low reaction temperatures, short reactor residence
times, and suitable catalysts. (268 Application at 21:26–31.)
6. Alternatively, the inventors state that prior to use as a flame retardant,
IPP samples may be subjected to art-recognized purification and separation
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