Lifang lawyers, Xie Guanbin and Sun Xi, have won a hard battle defending one of Rhodia's vital patents in a patent invalidation action filed by HySci (Tianjin) Specialty Materials Co., Ltd. In the first round, SIPO's Patent Reexamination Board (PRB) decided part of the patent invalid. Rhodia then filed an administrative action against the PRB. Both the first and second instance courts ruled to revoke the part of PRB decision that declared Rhodia's patent partly invalid. Eventually, the PRB recently issued a new decision and the entire patent has been maintained valid.