DETAILED ACTION
Status of Claims
Applicant's arguments filed 08/25/2026 have been fully considered but they are not persuasive. The previous prior art rejection over Burrous et al. (US 3,649,721) is maintained and reiterated below. See Response to Arguments. Claims 1-21 are pending.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 2, 4, 5, and 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over Burrous et al. (US 3,649,721).
Regarding claims 1 and 9, Burrous teaches hydraulic fluids comprising:
a phosphate ester fluid generally containing several phosphate esters mixed together; in a preferred type of fluid, the phosphate ester portion contains only trialkyl and triaryl phosphate esters (col. 5, lines 7-12).
More specifically, the trialkyl phosphates may include trioctyl phosphate, tridecyl phosphate, tridodecyl phosphate, and hexyl dioctyl phosphate reading on Applicant’s formula (I) (col. 4, lines 31-41). The triaryl phosphate may include triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, trinaphthyl phosphate, tri(ethylphenyl) phosphate, phenyl dicresyl phosphate, phenyl dixylyl phosphate, cresyl dixylyl phosphate, diphenyl cresyl phosphate, phenyl cresyl xylyl phosphate, phenyl di(ethylphenyl) phosphate, tricumyl phosphate, phenyl dicumyl phosphate, cresyl dicumyl phosphate, and tri(3,5-isopropylphenyl) phosphate reading on Applicant’s formula (II) (col. 4, lines 43-58).
With respect to for immersion cooling of electrical componentry, the preamble is viewed as intended use. See MPEP 2111.02: Effect of Preamble. The determination of whether a preamble limits a claim is made on a case-by-case basis in light of the facts in each case. In this case, the above hydraulic fluid could be capable of being used as a heat transfer fluid because (1) the composition does not include components that would not allow the hydraulic fluids to function as a heat transfer fluid, (2) deemed safe for use in commercial jet crafts (col. 1, lines 34-36); and has low flammability (col. 1, lines 45-46).
It would have been obvious to one of ordinary skill in the art before the effective filing date to select an alkyl phosphate ester with C6-16 alkyl groups from the list recited.
Regarding claim 2, Burrous teaches preferably 80-92 wt.% trialkyl phosphate ester with the remainder being triaryl phosphate ester (col. 5, lines 13-16), which overlaps Applicant’s claimed range of 10:1 to 1:10.
It would have been obvious to one of ordinary skill in the art before the effective filing date to have the recited composition ratio because a prima facie case of obviousness exists in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). Furthermore, "[ A ] prior art reference that discloses a range encompassing a somewhat narrower claimed range is sufficient to establish a prima facie case of obviousness." In re Peterson, 315 F.3d 1325, 1330, 65 USPQ2d 1379, 1382-83 (Fed. Cir. 2003). See MPEP 2144.05.
Regarding claim 4, Burrous further teaches mixed alkyl/aryl phosphates (col. 4, lines 59-70).
Regarding claim 5, Burrous teaches triphenyl phosphate and tricresyl phosphate (col 4, lines 44-45).
Regarding claims 10 and 11, Burrous teaches the phosphate ester portion is normally 75-95 weight percent of the total fluid, and preferably 85-95 weight percent (col. 5, lines 16-18). See MPEP 2144.05.
Allowable Subject Matter
Claims 3 and 6-8 are objected to as being dependent upon a rejected base claim but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claims 12-21 are allowable.
Response to Arguments
Applicant argues Burrous et al. (US 3,649,721) teaches numerous phosphates outside the structural scope of the presently claimed (e.g., C1-C5) and does not identify the claimed C6-C18 alkyl phosphate ester component but instead provides broad genus compassing numerous different phosphates. In reply, Burrous expressly recites species trioctyl phosphate, tridecyl phosphate, tridodecyl phosphate, and hexyl dioctyl phosphate reading on Applicant’s formula (I) (col. 4, lines 31-41).
Applicant argues Burrous would not have led a person of ordinary skill in the art to select the combination for immersion cooling. In response, it is respectfully submitted that Applicant is claiming a heat transfer fluid comprising two phosphate esters with formula (I) and formula (II); in other word, a composition. Burrous teaches in a preferred type of fluid (composition) is the phosphate ester portion containing only trialkyl and triaryl phosphate esters (col. 5, lines 7-12). The limitation of “for immersion cooling” is viewed as intended use as presented above.
Applicant argues Burrous does not teach the recited ratios of claim 2 because the ratios are for aircraft hydraulic fluids. In response, as stated above, Applicant is claiming a composition and Burrous teaches the ratio for the composition is preferably 80-92 wt.% trialkyl phosphate ester with the remainder being triaryl phosphate ester (col. 5, lines 13-16).
Applicant argues Burrous' listing of triphenyl phosphate and tricresyl phosphate is insufficient. In reply, Burrous expressly lists these phosphates which read on Applicant’s claimed mixed phosphate esters. For these reasons the prior art rejection is maintained.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CARLOS BARCENA whose telephone number is (571)270-5780. The examiner can normally be reached Monday-Thursday 8-5 pm.
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/CARLOS BARCENA/Primary Examiner, Art Unit 1723
