Polymer Case Means More Precise Patents

A dispute involving polymer properties has become an important test case for how the federal courts interpret patent claims. Taking hold are new, more exacting standards that inventors will need to consider as they stake out intellectual property.

The case involves Dow Chemical and Nova Chemicals, two giants of the North American polyethylene business. Dow filed suit against Nova in 2005, alleging that Nova’s Surpass brand polyethylene infringed patents related to its Elite resins.

Both are linear low-density polyethylenes notable for their strength and ease of processing. They compete in products such as stretch film and shipping sacks. Surpass and Elite are even made using similar solution-phase polyethylene processes.

The courts delivered win after win to Dow. In 2010, a jury awarded the firm $62 million in lost profits and royalties. After losing appeals, Nova paid Dow $77 million in 2012. Last year, a district court in Delaware awarded Dow another $30 million in damages for further infringement from the time of the jury award to the date the Dow patents expired in 2011. The Court of Appeals for the Federal Circuit affirmed the decision, and Nova again appealed.

Nova wasn’t having much luck, but a concurrent Supreme Court case, Nautilus v. Biosig Instruments, would change the course of its pending appeal.

Biosig maintained that Nautilus infringed on its patents on heart rate monitors embedded in the handlebars of exercise machines. Biosig’s patents claimed a configuration of electrodes that picked up electrocardiograph signals from the heart while filtering out conflicting electromyogram signals from muscles.

At issue was Biosig’s wording that the electrodes should be mounted in a “spaced relationship with each other.” Nautilus held that the wording was too vague for the patent to be enforced. Biosig maintained that an engineer could engage in a “trial and error” process to hit on the right configuration. A district court agreed with Nautilus, while the circuit court sided with Biosig.

The Supreme Court used the case to clarify the meaning of indefiniteness: a lack of precision about what activities do, and do not, infringe a patent. The test that the circuit court had been using is whether the claim was “not amenable to construction” or “insolubly ambiguous.”

Unanimously, the Supreme Court justices considered that language too vague. “Such terminology,” wrote Justice Ruth Bader Ginsburg in her opinion “can leave the courts and the patent bar at sea without a reliable compass.”

In place of this standard, the Supreme Court held that a patent is indefinite if its claims “fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

Emboldened by that decision, Nova argued to the circuit court that Dow’s patent claims were indefinite. At issue was a Dow claim that polymers covered under its patent would have a “slope of strain hardening coefficient greater than or equal to 1.3.”

This description relates to a graphical plot of data derived by testing polymer displacement under varying strains. The slope in question is the maximum slope of the curve generated as a load on a ­polymer sample is being increased.

But the court found three different ways to determine the slope of strain hardening from the data, and yet none was specified in Dow’s patents. A Dow expert even testified to a fourth method involving a linear regression of the data.

During oral arguments, the circuit court hectored Dow’s counsel, Harry J. Roper, for having a claim that rests on four measurements, each of which can yield different results. Roper countered that a skilled technician would select the appropriate method to fit the given situation. “You would always know, no matter what method you used, what the maximum was,” he said.

That, the court decided, didn’t pass the new test the Supreme Court handed down in Nautilus, and it switched its opinion in favor of Nova. “We conclude that our prior decision is not binding on the issue of indefiniteness because Nautilus changed the applicable law,” the court explained in its ruling late last month.

Jason Rantanen, associate law professor at the University of Iowa, says the Nova case was a true test of the new indefiniteness standard. The circuit court looked at the same evidence that it did in the first appeal, but the second time it did so through the new indefiniteness lens. “It’s the only variable that has changed in this case,” he notes.

In addition, the Nova case is a sign that the circuit court regards the Nautilus standard as a change in the law, not just in semantics. This shift, Rantanen says, wasn’t clear from other decisions after Nautilus in which the court continued to demonstrate a reluctance to find claims indefinite.

Even in the Nautilus case itself, on remand from the Supreme Court, the circuit court didn’t find Biosig’s claims to be indefinite. In the Nova case, in contrast, “there is a real change in the indefiniteness law, so much so that the outcome of the case gets flipped,” he notes.

The Nautilus standard will complicate the art of writing patents, Rantanen says. “There’s a higher risk of indefiniteness,” he says, though on the other hand including too much information can limit the scope of a patent. “The applicant may want some flexibility. That is something that patent attorneys are going to be thinking about as they draft claims going forward: How do you balance these risks?”