Celanese is once again suing a Chinese sweetener manufacturer over alleged infringement of its intellectual property.

The US specialty materials and chemicals company has filed another lawsuit against Anhui Jinhe Industrial, accusing it of continuing to unlawfully manufacture, sell and use Celanese’s Ace-K sweetener in China.

According to Celanese, the patent referred to in the lawsuit provides exclusive and “substantial technology advantages” to both itself and its customers for the production and quality of Sunett Ace-K sweeteners.

The US Patent and Trademark Office granted four new patents to Celanese in August 2018 covering improvements to the Ace-K manufacturing process.

In a previous lawsuit filed in March 2017, Celanese alleged that Anhui Jinhe Industrial as well as Suzhou Hope Technology and VitaSweet, were infringing its European patent by unlawfully importing Ace-K sweetener into Europe.

Celanese then filed another patent infringement lawsuit against Poland’s Falken Trade Polska in December 2017. Falken was a distributor of Ace-K produced by an undisclosed Chinese manufacturer — Celanese was also claiming compensation for damages.

“As the inventor and only Western producer of Sunett Ace-K, Celanese has developed a series of best practices to deliver one of the industry’s highest quality artificial sweeteners, ensuring product purity, supply reliability and product accountability,” said Tom Kelly, Celanese senior vice president, engineered materials. “We will vigorously defend our patented technology against unlawful manufacturing, importing, purchasing, selling, or use of proprietary technologies in the United States, Europe, China and globally.”

Sunett Ace-K is a zero-calorie, high intensity sweetener that is two hundred times sweeter than sugar. Celanese said demand for Ace-K continues to grow as consumers look for alternatives to full-sugar products.