Abstract
Synopsis
The patent examiner rejected as obvious claims directed to herbicidal formulations containing glyphosate salt with a surfactant system, finding the claimed formulations could be arrived at through “routine optimization” of formulations generically described in a prior art reference. The Patent Trial and Appeal Board (“Board”) affirmed, finding that the applicant had “failed to provide evidence that it would not have been routine optimization for a skilled artisan to select and adjust the claimed surfactants to achieve” the claimed invention. On appeal, the Federal Circuit vacated the Board's decision, finding that the Board had failed to adequately articulate its reasoning, erroneously rejected relevant evidence of nonobviousness, and improperly shifted the burden of proving patentability onto the applicant.
Stepan Company (“Stepan”) appeals from a decision of the Patent Trial and Appeal Board (“Board”) affirming the examiner's rejection of claims 1–31 of U.S. Patent Application No. 12/456,567 (“the ’567 application”). For the reasons discussed below, we vacate and remand.
Background
The ’567 application is directed to herbicidal formulations containing glyphosate salt with a surfactant system. Surfactants can enhance glyphosate's effectiveness as an herbicide by providing better adherence to leaves, thereby enhancing penetration. According to the specification, “[t]he present invention is based on the unexpected discovery that surfactant systems comprising dialkoxylated alkylamine, water miscible solubilizer and amine oxide allow for formulation of ultra-high loaded (‘high-strength’) glyphosate salt concentrates possessing high or no cloud points.” A cloud point is the temperature at which a solution becomes cloudy due to the surfactants becoming insoluble and separating into layers. Cloudiness can be avoided if the cloud point is higher than the solution's temperature or if the solution is cooled before adding the surfactant. The specification explains that because glyphosate salt is created at about 75°C, it is advantageous to formulate glyphosate with a surfactant system exhibiting a high cloud point to “obviate the necessity of waiting for the temperature of the glyphosate salt reaction product to cool down.” Surfactant systems with high cloud points or no cloud point, in which the solution never becomes cloudy, allow for quicker formulation of glyphosate concentrates and thus quicker delivery to the market.
Claim 1 is the sole independent claim:
1. An ultra-high load, aqueous glyphosate salt-containing concentrate comprising:
a. water;
b. glyphosate salt in solution in the water in an amount greater than about 39 weight percent of acid equivalent, based on the weight of the concentrate, said glyphosate salt being selected from the group consisting of the isopropylamine salt of glyphosate, the potassium salt of glyphosate, mixtures of the isopropylamine salt and the potassium salt of glyphosate and mixtures of the potassium salt and the ammonium salt of glyphosate;
c. a surfactant system in an amount ranging from about 1 to about 20 weight percent, based on the weight of the concentrate, comprising:
i. from about 10 to about 60 weight percent, based on the weight of the surfactant system, of one or more dialkoxylated alkylamines;
ii. from about 5 to about 30 weight percent, based on the weight of the surfactant system, of one or more water miscible solubilizers; and
iii. from about 30 to about 75 weight percent, based on the weight of the surfactant system, of one or more amine oxides;
said concentrate having a cloud point above at least 70°C. or no cloud point when the concentrate is heated to its boiling point.
Several dependent claims further limit the surfactant system of claim 1. For example, claims 20–24 specify that the dialkoxylated alkylamine is diethoxylated tallow amine. Claim 26 specifies that the water miscible solubilizer is a polyalkylene glycol with a molecular weight from about 200 to about 1000, and claim 27 further limits the water miscible solubilizer to polyethylene glycol. Claim 29 states the amine oxide is selected from a group of six amine oxides, among which includes lauryl dimethylamine oxide.
The examiner rejected claims 1–25 and 28–31 for obviousness over U.S. Pub. No. 2003/0087764, titled “Stable Liquid Pesticide Compositions” (“Pallas”). Pallas discloses highly-loaded glyphosate compositions containing surfactants having a cloud point of at least 50°C and ideally 60°C. Relevant to Stepan's appeal, the examiner found Pallas teaches preferred surfactants “includ[ing] the amine oxide lauryl dimethylamine oxide (Chemoxide [L70]) and the dialkoxylated amine diethoxylated tallow amine (Ethomeen T).” She found that Pallas teaches a surfactant component “may optionally contain glycols such as polypropylene glycol.” For the claimed ranges of the surfactants, she found “it is routine optimization to select and adjust the surfactants to this range since Pallas teaches the surfactant component comprises any combination of surfactants.” The examiner found Pallas does not teach a cloud point above 70°C but that achieving this cloud point would be a matter of “optimizing the formulation” because Pallas teaches the ideal cloud point should be above 60°C.
The examiner rejected claims 26 and 27 over Pallas in view of U.S. Patent No. 5,843,866, titled “Pesticidal Compositions Comprising Solutions of Polyurea and/or Polyurethane” (“Parker”). The examiner found Pallas does not teach the specific water miscible solubilizer polyethylene glycol with a molecular weight from about 200 to about 1000, but Parker discloses polyethylene glycol 600 in a surfactant system mixed with tallow amine and used with glyphosate. She found a skilled artisan “would have been motivated to make the formulation because Parker et al. teach that surfactant systems for glyphosate were known to have polyethylene glycol 600 with tallow amine surfactants.”
The Board adopted the examiner's findings in support of rejection and agreed with her conclusion that claims 1–31 would have been obvious. It determined Stepan failed to rebut the examiner's prima facie case of obviousness and affirmed the examiner's rejections. Stepan appeals. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A).
Discussion
The Board found Stepan failed to provide evidence that it would not have been routine optimization for a skilled artisan to select and adjust the claimed surfactants to achieve a cloud point above at least 70°C “since Pallas teaches the surfactant component comprises any combination of surfactants” and “teaches the ideal cloud point should be above 60[°C].” It rejected evidence in Pallas that certain surfactant combinations failed the cloud point test at 60°C because it concluded that these failures did not involve the claimed surfactants. It found Stepan failed to establish the criticality of its claimed range of surfactants, showing neither that a 70°C cloud point was unexpectedly good nor that the prior art was silent on the connection between optimizing surfactants and cloud point. Because the Board failed to adequately articulate its reasoning, erroneously rejected relevant evidence of nonobviousness, and improperly shifted to Stepan the burden of proving patentability, we vacate the Board's decision that claims 1–31 of the ’567 application would have been obvious.
The Board failed to explain why it would have been “routine optimization” to select and adjust the claimed surfactants and achieve a cloud point above at least 70°C. The agency tribunal must make findings of relevant facts, and present its reasoning in sufficient detail that the court may conduct meaningful review of the agency action. Stating that a person of ordinary skill in the art would have arrived at the claimed invention through routine optimization falls short of this standard. Missing from the Board's analysis is an explanation as to why it would have been routine optimization to arrive at the claimed invention. Similar to cases in which the Board found claimed inventions would have been “intuitive” or “common sense,” the Board must provide some rational underpinning explaining why a person of ordinary skill in the art would have arrived at the claimed invention through routine optimization.
The PTO argues substantial evidence supports the Board's finding that formulating the claimed surfactant system with a cloud point above at least 70°C would have been a matter of routine experimentation. It argues the thousands of formulations screened by Pallas indicate the routine nature of combining the surfactants and testing their cloud point. It argues these tests can be easily conducted in a short period of time and would have been tested by a skilled artisan as a matter of course. And it argues a skilled artisan would have selected the claimed surfactant system among those disclosed because Pallas teaches, inter alia, that amine oxides and dialkoxylated alkylamines are two of only four preferred surfactants. This evidence could be relevant to whether there would have been a motivation to combine the claimed surfactants with a reasonable expectation of achieving a cloud point above at least 70°C. The Board, however, did not make any of these findings. We may not accept appellate counsel's post hoc rationalization for agency action. We leave it to the Board to assess these arguments on remand.
Nor did the Board articulate why a person of ordinary skill in the art would have had a reasonable expectation of success to formulate the claimed surfactant system with a cloud point above at least 70°C. The Board's purported explanation that “Pallas teaches the surfactant component comprises any combination of surfactants” and “teaches the ideal cloud point should be above 60[°C]” does not indicate whether a skilled artisan would have had a reasonable expectation of success. To have a reasonable expectation of success, one must be motivated to do more than merely to vary all parameters or try each of numerous possible choices until one possibly arrived at a successful result. Reciting Pallas' teachings that “any combination” of surfactants may be used and that a cloud point above 60°C is desired fails to illuminate why a skilled artisan would have selected the claimed combination of surfactants and reasonably expected a cloud point above at least 70°C.
Lastly, the Board erred when it shifted the burden of proving patentability to Stepan. The PTO bears the burden of establishing a prima facie case of obviousness. Only if this burden is met does the burden of coming forward with rebuttal argument or evidence shift to the applicant. In holding that Stepan had not met its burden, the Board cited case law in which the patentee claimed a range within the prior art and had to rebut a prima facie case of obviousness by showing criticality of its claimed range. This line of case law does not apply here for two reasons. First, for the reasons discussed above, the Board did not establish a prima facie case of obviousness because it failed to adequately articulate its reasoning. Second, Stepan's ’567 application does not merely claim a range of surfactants that is within or overlaps with the range of surfactant systems taught by Pallas. The claimed surfactant system contains four elements. The first three elements describe the surfactants, and their respective ranges, that comprise the surfactant system. The fourth element limits the combination of those surfactants to only those combinations that produce a cloud point above at least 70°C or no cloud point at all. The cloud point thus limits and defines the scope of what surfactant combinations satisfy the claimed composition. It therefore may be that not all compositions that contain the claimed combination and range of surfactants fall within the claims. As an element of the composition claims, it was the PTO's—not Stepan's—burden to show that achieving a cloud point above 70°C would have been obvious to a person of ordinary skill in the art. To the extent the Board shifted the burden to Stepan to show the criticality of the cloud point element, the Board erred.
Conclusion
For the reasons discussed above, we vacate the Board's decision holding claims 1–31 of the ’567 application would have been obvious and remand for further proceedings consistent with this opinion.