What are the main industrial applications of sodium tripolyphosphate beyond food?

What are the main industrial applications of sodium tripolyphosphate beyond food?
STPP is primarily used in synthetic detergents as a builder, where it chelates calcium and magnesium ions in hard water, enhances soil removal, and provides pH buffering. It also prevents caking in powdered detergents. Other industrial uses include water softening, leather pre-tanning, dyeing auxiliaries, ceramic dispersants, papermaking, and rubber manufacturing. In China, detergent production is the largest downstream sector, but environmental concerns over phosphorus-induced eutrophication have led to declining use in laundry powders, pushing producers to seek alternative applications. STPP capacity is concentrated in Southwest and Central China, with key players like Xingfa Group (250 kt/year), Yibin Tianyuan, and Chongqing Chuandong.