Leaders in Beijing say they are keen to reform China's large state-owned enterprises, and their commitment is about to get an early test from an unexpected quarter in a Beijing courtroom.

European chemical company Ineos last week sued several units of state-owned China Petroleum & Chemical Corp., known as Sinopec, for breach of Ineos's patents. Ineos also filed an arbitration case against another Sinopec unit in Sweden. The European firm says the Chinese petro giant, with which it has a joint venture, has misused Ineos's patented manufacturing process for acrylonitrile, a component in carbon fiber products and other plastics. Ineos says Sinopec is building unauthorized factories based on the technology, with one plant already running for a year. Sinopec says the factories use technology it developed.

This appears to be the first time a foreign company has sued a Chinese state-owned enterprise in a Chinese court over an intellectual property dispute—or anything else. Foreign executives who believe they've been wronged typically are wary of angering a Chinese company's patrons in Beijing. Foreigners are also pessimistic about the fairness of China's courts. Many joint-ventures, the source of so much business conflict, try to bypass Chinese courts by providing for overseas arbitration.

Elements of the Ineos case make one wonder whether this might be due for a change. For Ineos, China's sheer scale has driven it to court. China has the means to radically alter the global market for acrylonitrile by ramping up production. "If they build a half-dozen copy plants, they'll destroy the acrylonitrile business," Ineos CEO Jim Ratcliffe tells me.

The implication is that the bigger China grows, the more damage it is able to do through IP abuse or other corporate mischief, and the more likely that foreign companies' survival instincts will trump their political squeamishness about taking strong action. State-owned firms will be a logical target since their scale makes them particularly dangerous.