Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Objections
The word "mixture" should be added after the word "precursor" in the next-to-last line of claim 31 to ensure consistency of terminology and avoid possible antecedent basis issues in this claim.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 31-37, and 47 are rejected under 35 U.S.C. 103 as being unpatentable over Iwata et al., WO 2021/095501. To the extent that it evolved from a National stage application of the aforementioned international disclosure, U.S. Patent Application Publication No. 2022/0411589 is believed to have an identical disclosure and is used as a faithful translation of the WIPO document into the English language. All citation of teaching location will be those for the U.S. publication.
Applicants are directed to Example 1-1 where there is disclosed the preparation of a composition having application as a thermal interface material for heat generating electronic devices [0001] comprising 100 parts of a vinyl-terminated polydimethylsiloxane (or 8.9% of the total), 1.26 parts of methylhydrogensiloxane crosslinker and 9.4 parts of a SiH-terminated oligodimethylsiloxane chain extender (or 0.94% hydrosilyl group-bearing components as a fraction of the total), 18 parts of a polydiorganosiloxane bearing alkoxysilyl groups at one terminus used to treat 1000 parts (88.6% of the total) of aluminum oxide with a couple of particle populations of differing average diameter, chloroplatinic acid catalyst, and ethynyl cyclohexanol inhibitor (0.016% of catalyst and inhibitor respectively). While apparently having been formulated as a one-part composition in this example, two-part compositions are contemplated in the alternative- see [0012] and the skilled artisan is cognizant of the idea that these may be assembled in various combinations of materials provided that the base polymer, crosslinker, and catalyst are not all combined together in a single part. Whereas the Examiner acknowledges that the amount of organohydrogensiloxane crosslinker added is very slightly less than the lower endpoint of the claimed range, there is no evidence in the current record that 1 wt.% represents a critical point. Indeed, the Examiner observes that, generally speaking, the relative amounts of SiH groups contributed by the crosslinking agent relative to the number of alkenyl groups furnished by the base polymer are regarded by one of ordinary skill as being a far more salient parameter, as opposed to the relative quantities in weight terms. Given the substantial compositional parallels between the claimed- and prior art compositions, a skilled practitioner has a reasonable expectation of the latter’s thermal conductivity inherently being consistent with that of the former.
As for the employment of a maleate/fumarate as an inhibitor, the Examiner appreciates that ethynyl cyclohexanol is used instead in Example 1 but, on the other hand, maleates are identified as a functional equivalent in [0174]. Finally, as before, the reference discloses at [0186] a viscosity believed to correlate with the claimed initial viscosity of preferably 30-700 Pa.s at a shear rate of 6 sec-1, which is obviously a considerably slower shear speed. It is not clear that a viscosity under one set of shear conditions can be readily correlated with those at another. On the other hand, this same passage explains the importance of tailoring the viscosity to achieve a proper balance of shape retention upon application and dischargeability/workability and it is the position of the Office that, in the act of simultaneously optimizing for both parameters at shear rates of either 1 s-1 or 100 s-1, a skilled practitioner of the prior art invention would conclude that the values recited at the end of claim 1 would be desirable, especially given that both the instant Specification and reference contemplate the compositions being used in a similar capacity.
Regarding claim 35, thixotropy, or the property of a material undergoing elastic deformation in response to the application of a force, would be recognized by one of ordinary skill as being a desirable characteristic of a thermal interface material so that that it can be temporarily deformed to fill the small and often architecturally complex gaps/crevices spanning heat-emitting surfaces and heat spreaders/sinks in an electronic device while not flowing in the absence of a force/under typical operating conditions of said device. That is, it would at least be obvious that a formulator with ordinary skill would add materials to the prior art composition that render it thixotropic, assuming it is not already.
Concerning claim 36, the prior art does not appear to anywhere characterize the durometer of the filled elastomer derived from the prior art composition but, rather, only discloses its Shore 00 hardness in a pre-cured state, both initially and after storage. Again, because the claimed- and prior art compositions have similar utility, it is the Examiner’s position that one of ordinary skill would aim to formulate a composition with a comparable post-cure hardness.
Claim 47 defines a composition broader in some respects as compared to claim 1 and narrower at least in that it attaches a limitation reflective of storage stability (viscosity increases occurring under storage conditions over a period of 14 days). Applicant will note that Tables 1-4 all document nearly negligible change in the viscosity of the composition when held at 5° C over 6 months.
Claims 18-23 and 38-46 are rejected under 35 U.S.C. 103 as being unpatentable over Iwata et al., WO 2021/095501 in view of Hu et al., WO 2020/093258 and/or U.S. 2018/0030327 and/or the YouTube video entitled “Application of Thermal Interface Material” available at the URL https://www.youtube.com/watch?v=AtTaAUd6-js.
Iwata is relevant for all the reasons outlined supra addressing the limitations of claims 39 and 40, and the compositional aspects of claims 18, 20 and 43-44. It is not forthcoming as to the means of application of the composition but Hu [0074], Zhang et al., and the YouTube video all demonstrate that administering the composition from a syringe is a known, actually conventional, approach for applying the composition between a heat generating body and a heat radiating body ([0002] of Iwata), and, therefore, the packaging of the prior art composition in a vessel with an orifice, a syringe, would have been obvious at the time of the invention. Although there is no express suggestion of keeping the curable composition in said vessel/syringe for at least 24 hours prior to use, it is understood that the composition-filled vessel represents a form for commercial sale and that the mixture would reside in the syringe for much more than 24 hours. Paragraph [0190] says that curing conditions are the same as are conventionally known, and 40° to 180° C for 1 minute to hour in particular.
As for claims 41 and 42, none of the aforementioned references report a suitable diameter for the exit port/orifice of the syringe, although the syringe shown in the video looks to comply with the limitation of claim 42. The Examiner takes notice of the fact, however, that one of ordinary skill would select a syringe with orifice/opening sizes tailored to produce a “dot” or “line” of a particular diameter/width dictated by the particular application. To the extent that all of the references are directed to the same application as is the claimed composition, a syringe with a similar orifice diameter would be chosen. A syringe filled with a composition of very similar makeup, and with a comparable initial viscosity, ejected from a syringe with an applied pressure of 90 psi will necessarily exhibit a flow rate of the composition consistent with that of claim 41.
Response to Arguments
“This claimed approach is fundamentally different from Iwata2, and Iwata2 in view of Hu and/or the YouTube Video does not disclose or otherwise render obvious at least the following features of Claim 18: "(iv) less than 0.1 wt.% of a reaction inhibitor effective to interact with the reaction catalyst to slow a reaction rate between the first and second reactant compositions at a storage temperature of less than 40°C; (b) storing the curable mixture in a vessel for more than 24 hours at the storage temperature; and (c) dispensing the curable mixture from the vessel through an orifice onto the surface.”
As an initial matter, there is incorporated into Example 1 an initiator in a calculated amount of 0.016% by weight. As for storage limitation (b), the rejection makes clear that it is known to package the thermal interface material composition in a syringe with an orifice for ejection of the composition into the desired cavities of the electronic device, the orifice of course representing the opening through which the composition is dispensed. As to the notion that the compositions wouldn’t be stored for at least 24 hours in a syringe, the entity to which the prior art disclosure is assigned is Shin Etsu, a silicones manufacturer, not an electronic device producer. Therefore, the silicone compositions described therein are not formulated in the electronic device production environment where they would be immediately used but, rather, are obviously manufactured and packaged (in a syringe) by the assignee company named in the Iwata disclosure and made available for commercial sale. In this scenario, the composition would unquestionably be stored in a syringe for at least 24 hours and likely much longer. As for the storage temperature, generally the ambient conditions of a storage facility will be maintained at temperatures below 40° C.
“Specifically, Iwata2 discloses a "two pack" configuration in which reactive components are intentionally segregated (Iwata2, [0029]-[0032])…. This explicit teaching that storage stability is achieved through component segregation teaches away from the claimed invention, which achieves storage stability through a fundamentally different mechanism, in particular, with an inhibitor…”
Iwata teaches one and two-pack compositions alike, the description of the former beginning at [0047] and the latter at [0111]. Example 1-1, the composition of which is summarized above, is a 1-part composition.
“Consistent with this teaching, Iwata2 is silent as to storage of a "curable mixture" containing components (A), (B)/(D)/(H), and (E) together in a single vessel… Instead, Iwata2 contemplates that once the two packs are combined, curing proceeds under conventional curing conditions, including heating at elevated temperatures, with curing conditions being described as "well known" (Iwata2, [0190])...”
It is acknowledged that Iwata doesn’t explicitly disclose the packaging/storing aspects (although at least the latter is plainly obvious from Iwata alone since it is a commercial product made for purchase) of the claimed invention, which is why the teachings of Hu and the YouTube video are invoked. One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986)
“Ethynyl cyclohexanol in Iwata2 serves only as a conventional cure retarder to provide working time during processing. Iwata2 does not teach or suggest that the ethynyl cyclohexanol enables "storing the curable mixture in a vessel for more than 24 hours at the storage temperature" of "less than 40°C," or that the mixture remains suitable for "dispensing from the vessel through an orifice onto the surface" after such storage.”
Implicit in Applicants’ remarks is that one of ordinary skill harbors no reasonable expectation that ethynyl cyclohexanol is an effective enough inhibitor to preclude cure at storage conditions. The Examiner respectfully disagrees as this particular inhibitor is mentioned repeatedly in the literature as a capable inhibitor, including in one-part compositions.
“Example 1-5 affirmatively demonstrates that Iwata2's approach is the opposite of the claimed method and teaches away from storing an uncured mixture. Example 1-5 demonstrates what is done with the curable composition of Example 1-1 (Iwata2, [0204]-[0205]). The sequence in Example 1-5 is as follows…”
One of ordinary skill does not infer from Comparative Example 1-5 that curing should precede storage. The sequence of operations outlined in that passage was carried out for testing purposes only. It would be readily understood by the skilled artisan that a thermal interface material will not be applied to an electronic device in an already-cured (and, thus, unflowable) form.
“The instant Specification explains the technical significance of the claimed single-component approach. The Specification at [0006]-[0007] describes that "form-in-place" thermal interface materials "may be applied as a liquid or semi-solid precursor, and subsequently cured in-place" and that such materials must be "dispensable from a single-component dispensing systems" while remaining "stable" over extended periods. The Specification at [0014] explains that the claimed inhibitor "may interact with the reaction catalyst to slow or prevent a reaction between the first and second reactant compositions at a storage temperature" to enable this extended storage. This technical contribution, enabling extended single-component storage of a fully curable mixture through inhibitor-based catalyst suppression, is precisely what Iwata2 fails to teach.”
Applicants’ assertion is simply untrue. Once more, Iwata teaches both one- and two-part compositions with the one-part composition being comprehensively described from [0047-0110]. Example 1-1 embodies the one-part composition and contains ethynyl cyclohexanol as an inhibitor while [0104] reflects that maleate compounds are regarded as functional equivalents thereof.
“…This concession is fatal to the rejection. Neither Iwata nor Iwata2 discloses any viscosity data at the claimed shear rates of 100 s⁻¹ or 1.0 s⁻¹, and the Action admits that viscosity values at different shear rates cannot be correlated. Without any teaching of the claimed viscosity parameters at the claimed shear rates, there can be no prima facie case of obviousness.”
The only impact of the Examiner’s concession is that the Examiner cannot hold with absolute certainty that the viscosity ranges defined at 100 s-1 and 1 s-1 are inherently met (though strongly suspects that they are).
“Under MPEP 2144.05(II)(B), a parameter may only be optimized through routine experimentation if the prior art recognizes that parameter as affecting the claimed result, or as being a result-effective variable. Neither Iwata nor Iwata2 measures, discusses, or recognizes viscosity at 100 s⁻¹ or 1.0 s⁻¹ as a result- effective variable. Both references measure viscosity only at intermediate shear rates (6 s⁻¹ or 10 rpm) and provide no guidance regarding the rheological profile at shear rates two orders of magnitude apart...”
Paragraph [0107] of Iwata ties the viscosity to both shape retention and dischargeability clearly establishing it as a result effective variable. Where the composition is added to a storage/dispensing vessel such as a syringe as Hu and Zhang suggest, one of ordinary skill will appreciate that the composition should (i) be in possession of viscosity at low shear that ensures shape retention, while (ii) also having suitable viscosity at high shear, i.e. the conditions under which the composition is expelled through the syringe orifice, and formulate the composition to accommodate both requirements.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 MARC S ZIMMER whose telephone number is (571)272-1096. The examiner can normally be reached M-F 8:30-5:00.
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April 9, 2026
/MARC S ZIMMER/Primary Patent Examiner, Art Unit 1765
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