PTAB Finds Teaching Away in Non-Overlapping Range

April 10, 2023

On March 15, 2023, the Patent Trial and Appeal Board (PTAB) of the United States Patent and Trademark Office (USPTO) issued an opinion in the appeal of US Appl. Ser. No. 15/395,642, Ex parte Chris Fish (Appeal 2022-001172, Technology Center 1700, Appellate Patent Judges Adrienne Lepiane HANLON, Catherine Q. TIMM, and Jeffrey B. ROBERTSON) reversing Examiner Nathan H. EMPIE’s finding of obviousness based on an alleged motivation to modify beyond the range taught by the prior art.

The main claim appealed recited (emphasis added)

   [a] method of coating a surface, which method comprises:
   (a) coating onto a surface a silicon-based composition comprising 1% to76% (w/w of the total composition) polysilazane, 1% to 9% (w/w of the total composition) polysilane, 0.2% to 4% (w/w of the total composition) polysiloxane, and at least one organic solvent;
   wherein the polysilazane is of a formula (R1R2SiNH)n, wherein n is 2 or more, and wherein R1 and R2 are the same or different and are chosen from alkyl, alkenyl, cycloalkyl, alkylamino, aryl, aralkyl, or alkylsilyl; and
   wherein the polysilane is of a formula (R1R2Si)n, wherein n is greater than 1, and wherein R1 and R2 are the same or different and are chosen from alkyl, alkenyl, cycloalkyl, alkylamino, aryl, aralkyl, or alkylsilyl; and
   (b) curing the coating ambiently to provide a coating.

In prosecution beginning with a December 30, 2016 filing, the applicant submitted a declaration in support of the claims and add the third clause, broadly defining R1 and R2 and that the polysilazane is a dimer. The applicant requested conference prior to the filing of the appeal brief, in which the applicant unsuccessfully argued before the examining corps regarding the primary reference, Duncan,

[t]he Office has failed to account for how the claimed chemistry differs in water reactivity and the amount of polysilazane compared to Duncan and Dziark.  Duncan’s car wax has a different chemistry than what is needed for the claimed mold release agents. Duncan uses up to 90% water.  The claimed compositions decompose in water[.] Thus, the claimed compositions were designed with different functional chemistries, which a person of skill in the art would quickly recognize.

The applicant further noted regarding the combined references, Duncan and Dziark, that

[t]he claimed compositions require 25 to 38,000 parts polysilazane relative to 100 parts polysiloxane. Dziark as a whole, however, directs away from using more than 10 parts of polysilazane in the composition[.] Dziark warns that “[i]t is not desirable to add too much of the scavenger since above 10 parts may detract from the cured physical properties of the composition.”[ ] In contrast, the claims require between 250% and 3,800,000% more polysilazane than the maximum amount expressly disclosed in Dziark. Duncan, being silent on polysilazanes, offers no guidance in this regard.

The applicant further argued that the combined art did not allow for the stronger polymer effects achieved by the claims because the cited art did not permit sufficient disilazane, and that the examining corps ignored all indicia of nonobviousness, which were detailed in an expert declaration under 37 CFR § 1.132.

Supervisory Patent Examiners (SPEs) Michael B. Cleveland (Art Unit 1712) and Christine S. Tierney (Art Unit 1700) supported the Examiner Empie’s finding that the claims were obvious without a need to reconsider any position taken in prosecution. The applicant’s appeal brief repeated and further detailed these arguments, and the Examiner’s Answer argued that the open language of the main claim allowed for the use of water in the claims, despite the technical explanation of the impossibility of doing so. The Examiner’s Answer also argued that the primary prior art reference’s teaching away from the amount of polysilazane usable was merely a preferred embodiment. The Dziark reference, US 4,417,042, at col. 10, l. 64, to col. 11, l. 8, states (emphasis added) in relevant part that

[t]he silyl-nitrogen compounds and polymers are the most preferred in the instant compositions as scavengers, then the above amines can also be utilized as scavengers in the RTV composition of the instant case. The only difficulty with the hydride amines is that they do tend to liberate hydrogen upon standing and also they tend to impart the undesirable odor of amines to the RTV composition.  However, if this is not a problem, then they can be tolerated in the instant composition. Preferably, the silyl-nitrogen compounds such as hexamethyldisilazane and the rest, are utilized in a concentration of 0.5 to 10 parts by weight per 100 parts of the base organopolysiloxane polymer.

The Examiner’s Answer finally argued that the expert declaration and results related only to particular commercial embodiments and were not commensurate[1] in scope with the claims.

The PTAB noted that there was “no dispute that Duncan [the primary reference], teaches or suggests a composition containing polysilane, polysiloxane, and organic solvent, but fails to teach adding polysilazane.” The PTAB took note, however, that “Dziark [the secondary reference] is directed to a different type of composition[,] … a room temperature vulcanizable (RTV) composition that vulcanizes to form a silicone rubber.” The PTAB acknowledged that Dziark’s use of polysilazanes related to scavenging water and R-OH compounds, and was limited by this utility against polisilazane’s detraction from physical properties of the cured material.

In a short 3-page opinion, PTAB concluded that the examining corps failed to establish “that scavenging would be desirable in the polish of Duncan, which is not cured in the same manner as Dziark’s RTV composition,” i.e., failed to establish a motivation to include polysilazanes at all, and agreed with the applicant that “Dziark teaches away from such high amounts given Dziark’s disclosure that amounts higher than 10 parts by weight may impact the properties of the end product rubber.”

The case is a reminder that the PTAB may be less beholden to an argument generated by the examiner than the SPEs and quality control examiners reviewing that examiner within the examining corps. As is often the case in prosecution, an examiner may rely on the mere existence or availability of a missing component from a different composition, and disregard the technical arguments about the utility of that missing component and its context in the secondary reference. Although the applicant here sought the review of senior examiners within the examining corps, in the Pre-Appeal Brief Request for Conference (PABRC), the senior examiners maintained the positions. An applicant should not be dissuaded from appealing a case when the examiner’s position is technically questionable by an unsuccessful PABRC, as the PABRC maintains the decision-making at the examining corps level. The SPEs are typically responsible for instilling in the less-senior examiners the anti-patent positions frequently encountered at the examining corps.

[1] “According to the application specification at Table 7 and Table 5 these products appear to correspond to 66/17/17 mixtures of ‘A/B/C resins’ and 50/50 mixtures of ‘B/C resins’. A, B, and C resins are further described in Tables 1, 2, and 3. The examiner notes that the DT 6060 product would appear to not possess any polysilazane as resins Band C do not possess any polysilazane (thus such a formulation would not be within the claimed scope), similarly any other formulations not possessing all of resins AB and C similarly would not possess polysilazane and thus would also not be within the scope of the claims which require 1-76% polysilazane. As Appellant has grouped such systems lacking all three silicon based components of claim 77 with those that do, the evidence is not commensurate in scope with the claims as argued beneficial results would thus occur beyond the claimed scope; and they do not support a finding that such results only occur over the entire claimed range.” Examiner’s Answer, paragraph bridging pp. 7 and 8.