Ever since DuPont scored a $920 million win last September in a trade secrets case against Kolon Industries over the fibers used in Kevlar body armor, Kolon and its lawyers at Paul Hastings have hoped to reverse their fortunes by pressing antitrust counterclaims that DuPont monopolized the Kevlar market. Kolon’s claims are still alive, but the company’s bid to ensure that they won’t be heard by the same judge fell flat on Tuesday.

Kolon’s lawyers at Paul Hastings argued that Richmond, Va., federal district court judge Robert Payne had a conflict of interest stemming from his days as a lawyer at McGuireWoods, which represents DuPont along with Crowell & Moring. But in a 43-page opinion, Judge Payne refused to recuse himself from the antitrust case, which was bifurcated from the DuPont’s trade secrets case before it went to trial. He issued a separate 47-page opinion Tuesday rejecting Kolon’s parallel request that he recuse himself from the trade secrets case, which is in post-trial stages.

Judge Payne disclosed as soon as he was assigned to the case in early 2009 that he worked at McGuireWoods in the 1980s, and the Paul Hasting lawyers didn’t object. But they formulated an argument in July 2011 that DuPont may have waived the confidentiality of some of its claimed trade secrets during a series of patent disputes in the 1980s with a company called Akzo. McGuireWoods advised DuPont on the Akzo litigation, and records kept by the firm indicated that Payne may have sent a copy of a complaint filed in the Akzo case to a colleague. Payne, for his part, denies ever working on the case.

The Kolon lawyers didn’t formally move for recusal last summer, but they told Judge Payne on the eve of jury selection in the trade secrets case that “there is some question as to whether Your Honor should be adjudicating these matters.” Payne reviewed the evidence and found no grounds for recusal. The Paul Hastings lawyers raised the issue again in recusal motion in November, as the discovery phase of their antitrust case came to a close. “That, on this record, is too late,” Payne wrote. “And, it is a legally insufficient predicate where, as here, Kolon knew long before trial of the facts it now asserts warrant recusal.”

Judge Payne also called “meritless” Kolon’s allegations that McGuireWoods knew about Payne’s supposed involvement in the Akzo case and hid the evidence. “Kolon appears to have changed its mind yet again as to why recusal is warranted. The court will not reward this type of tactical maneuvering,” he wrote.

Brian Riopelle of McGuireWoods, who represents DuPont, told us that the now expects Judge Payne to rule next on DuPont’s motion for attorney fees in the trade secrets case. The antitrust case, meanwhile, is currently scheduled to go to trial in April.

Jeffrey Randall of Paul Hastings, who filed the recusal motion for Kolon, did not return a call seeking comment.