PTAB Overturns Rejection for Overlapping Ranges

November 11, 2022

On October 19, 2022, the Patent Trial and Appeal Board (PTAB) overturned the obviousness rejection of a claim to an aqueous dispersion. Claim 1 of the application in question, USSN 16/083,182 (the 182 Application), recited

[a]n aqueous dispersion comprising

(a) 5% to 40% of a continuous phase, by weight based on the weight of the aqueous dispersion, wherein the continuous phase comprises 75% to 100% water, by weight based on the weight of the continuous phase, and

(b) 60% to 95% of a distributed phase, by weight based on the weight of the aqueous dispersion, wherein the distributed phase comprises, by weight based on the weight of the distributed phase,

(i) 2% to 20% ethylcellulose polymer,

(ii) 70% to 97% food oil,

(iii) 1 % to 10% dispersant,

wherein the distributed phase comprises dispersed particles that are solid at room temperature.

The obviousness rejection of the above claim over the combination of WO 1992/003937 A2 (Zaks) and WO 2015/031244 A1 (Rogers) was appealed in the 182 Application.

The 182 Application was filed with four claims. The sole independent claim recited the above features, except for the final clause, and was first rejected as obvious over the combination of Zaks and a different secondary reference. In response, the applicant added the final clause to claim 1 and argued that the art failed to describe or make obvious (1) solid particles dispersed in a continuous aqueous medium; (2) changing Zaks’s “oil-continuous emulsion having two liquid phases (liquid oil and water phases)” to “an aqueous dispersion having one solid phase and one liquid phase,” with water being the continuous phase as claimed; and (3) changing Zaks’s water-soluble aqueous gelling agents to being water-insoluble ethyl cellulose as claimed.

The examiner then finally rejected the claim over the combination of Zaks and Rogers, relying on Rogers for a dispersant being a fatty acid and for the use of ethylcellulose. The examiner relied merely upon Zaks’s overlapping ranges of the oil and water phases (“the emulsions generally contain from about 30 to 80% by weight of the oil phase, and about 20 to 70% by weight of the aqueous phase”) to argue that the specific continuous and distributed phases claimed would have been obvious, although Zaks described a continuous oil phase. The final rejection did not elaborate on a technical rationale for modifying this feature in Zaks, and merely relied upon the fact that the art taught mixing the oil and water phases.

The portion of Zaks relied upon by the examiner to reject the claims describes that

[t]he emulsions generally contain from about 30 to 80% by weight of the oil phase, and about 20 to 70% by weight of the aqueous phase. The oil phase contains from about 1 to 10% by weight of the polymer, and the aqueous phase contains from about 1 to 8% by weight of the aqueous - soluble gelling agent.

Zaks, p. 11, ¶ 2. In the paragraph bridging pp. 11 and 12, Zaks describes that “[t]he emulsion is assembled under shear… and the aqueous phase is slowly added [to the oil phase], forming an emulsion of the aqueous phase in a continuous external oil phase.” However, Zaks describes in its “Summary of the Invention” section from p. 2 onto p. 3 (emphasis added) that

[t]he invention relates to an oil or fat which contains a polymeric, fat-soluble material and its use for the modification of the physical properties of fats.  The polymeric material which can be used in the present invention includes oil soluble polymers, such as alkyd-type polyesters, polymers based on hydroxyacids and natural polymers, such as cutin.  …

The polymer also helps to stabilize and solidify emulsions. In this embodiment, the polymer is incorporated into an oil-in-water or water-in-oil emulsion, forming a material having the physical and structural characteristics of saturated fat but which contains no saturated fat.

Zaks describes at the outset of its “Detailed Description of the Invention” section on p. 4, ¶ 3, that “[p]olymers useful in the present invention are oil-soluble polymers …, such as cutin, polymers based on hydroxy acids and polymers prepared by the condensation of polyhydric alcohols and polybasic acids… polymers generally known as ‘alkyd’ polymers.” Zaks describes on p. 6, ¶ 3, that the “alkyd resins can be terminated using monohydric alcohols (e.g., diglycerides) or monobasic acids (e.g., fatty acids),” and that “[t]he choice of the terminal groups will depend in part on the properties of the polymer. For example, long-chain fatty acids are used where increased oil solubility is desired.” For the dispersions in which the oil content range relied upon by the examiner for the overlapping ranges, Zaks describes on p. 10, ¶ 3, that “either the water-in-oil or oil-in-water type can be made.”  However, Zaks describes (emphasis added) that the alkyd polymers are oil-soluble, while the “standard aqueous gelling agent” described on p. 10, ¶ 4, is, “for example, gelatin, xanthan gum, gum arabic, guar gum, pectin, algin, carrageenen and cellulose derivatives.”

The applicant appealed after the second rejection with roughly the same arguments (1) to (3) indicated above. The examiner answered that Zaks teaches that the key to the proper textural development of the spreadable emulsions is the combined action of the aqueous and oil gelling agents present in the mixture, and Zaks’s polymer is used as the gelling agent of Zaks’s oil phase, while a standard aqueous gelling agent is used in the aqueous phase.  The examiner argued that Zaks’s aqueous gelling agent may be “gelatin, xanthan gum, gum arabic, guar gum, pectin, algin, carrageenen and cellulose derivatives,” reproducing the examiner’s prior argument from prosecution. The examiner argued that Rogers’s teaching of the combination of an oil, ethylcellulose polymer, and water, with ethylcellulose polymer added to an aqueous phase, overlapped with Zaks and rendered the claim prima facie obvious. The examiner argued that Rogers did not disclose that the ethylcellulose polymer is non-aqueous.

The PTAB found the examiner’s position unpersuasive for at least three reasons. First, Zaks indicates that the gelling agents used in its aqueous phase are water soluble, and ethylcellulose is not water soluble. The PTAB argued that nothing in Zaks was identified that an aqueous-insoluble gelling agent would have been regarded as suitable.  Second, even if ethylcellulose would have been useable as Zaks’ water-soluble cellulose derivative, ethylcellulose would have been in Zaks’ aqueous phase, whereas claim 1 requires ethylcellulose in the oil phase.  The PTAB found this rationale is unpersuasive because it was not shown that the same product would result from ethylcellulose being in water phase or the oil phase.  Third, it was not disputed that Zaks’s continuous phase is the oil phase while the claim requires an aqueous continuous phase. The PTAB found that the continuous phase in Rogers being aqueous does not make obvious substituting Rogers’s aqueous continuous phase for Zaks’s oil continuous phase.

Thus, the PTAB affirmed that a mere overlap in possible features in the prior art do not necessarily render obvious a claim reciting specific components and phase phenomena, which are not necessarily present based upon the overlapping concentration ranges. MPEP § 2144.05 ( may be familiar to some applicants regarding overlapping ranges, as well as the liberal use / combination of generic disclosure by the USPTO examining corps. The application of this MPEP section is often accompanied by reference to In re Wertheim, 541 F.2d 257 (CCPA 1976)[1] and, for close, but non-overlapping ranges, Titanium Metals Corp. of America v. Banner, 778 F.2d 775 (Fed. Cir. 1985)[2].

As in the case of the 182 Application, an examiner must establish a reason to modify the underlying primary reference, if the claim has more than a simple overlap of percentages with the prior art. For the 182 Application, at least the location and function of the specific (but overlapped) ethylcellulose polymer – water insoluble and in the dispersed phase – appears to have played a role in the PTAB’s decision to reverse the examining corps. Moreover, one should keep in mind that for non-overlapping, but close ranges, the examiner needs to establish that “one skilled in the art would have expected [the prior art and claimed material] to have the same properties,” as indicated in Titanium Metals, 778 F.2d at 783. Finally, applicants should keep in mind that the PTAB may take a less restrictive view of non-obviousness in claims than the examining corps, including USPTO Art Unit heads, given the increasingly permissive obviousness reconstructions made by USPTO examiners and supported by (often instilled by) present day USPTO Supervisory Patent Examiners (SPEs).