Two US men have been convicted of stealing trade secrets and selling them to a Chinese state-owned company.
A California court found businessman Walter Liew and scientist Robert Maegerle guilty of economic espionage.
They stole US firm DuPont's secret method of making titanium dioxide, a whitener used in products including paint, paper and food, the court ruled.
The men sold the trade secrets to China's Pangang Group, the court added. They will be sentenced in June.
Liew and his wife started a company in the US in the 1990s and hired a team of ex-DuPont employees to steal DuPont's titanium dioxide trade secrets, the court said in its ruling.
Liew, his company USA Performance Technology Inc and Maegerle sold DuPont's secret recipe to Pangang Group for more than $20m (£12m), the court added.
Liew was taken into custody immediately over fears he could abscond, the BBC's Alastair Leithead in Los Angeles reports.
Two other scientists have been linked with the case - one committed suicide, the other admitted conspiracy to commit economic espionage, our correspondent adds.
Liew's lawyer, Stuart Gasner, said he was "very disappointed" in the verdict and would appeal.
The defence has argued that no trade secrets were stolen from DuPont, and that the information Liew held was in the public domain.
US Attorney Melinda Haaf said: "As today's verdict demonstrates, foreign governments threaten our economic and national security by engaging in aggressive and determined efforts to steal US intellectual property."
"We will aggressively pursue anyone, anywhere who attempts to steal valuable information from the United States," she added.
Liew's wife is scheduled to be tried separately.
Prosecutors have also charged Pangang Group, but the charges stalled after a US judge ruled that prosecutors' attempts to notify Pangang of the charges were legally insufficient, Reuters news agency reported.