Appeal No. 95-2149
Application No. 08/026,039
1. An improved fire resistant hydraulic base fluid
composition having a specific gravity of less than 1.03, and a
four-ball wear scar of less than .9 mm, the improvement
consisting essentially of 1 to 12 parts by weight of a
trialkoxyalkyl phosphate ester, each alkoxyalkyl moiety
containing about 6 to 10 carbon atoms, and 1 part by weight of
an ester or a mixture of esters selected from the group
consisting of a trialkyl ester of phosphoric acid and C4-C8
alkyl alcohols, a triaryl phosphate ester wherein the aryl
groups are partially C3 to C4 alkylated phenols, and a
trialkyl phosphite ester having a pour point of less than -
50EC, each alkyl group of the trialkyl phosphite ester
containing from 8 to 12 carbon atoms.
The examiner relies upon the following references as
evidence of obviousness:
Sheratte (Sheratte '324) 3,849,324 Nov. 19, 1974
Sheratte (Sheratte '129) 4,001,129 Jan. 4, 1977
Takao et al. (European '932) 0 135 932 Apr. 3, 1985
(European patent application)
Appellants' claimed invention is directed to a fire
resistant hydraulic base fluid consisting essentially of a
trialkoxyalkyl phosphate ester and a trialkyl phosphite ester.
A suitable trialkoxyalkyl phosphate ester is tributoxyethyl
phosphate, while triisooctyl phosphite is an example of an
trialkyl phosphite ester.
Appealed claims 1-14 stand rejected under 35 U.S.C. § 103
as being unpatentable over European '932.
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