Sodium Tripolyphosphate (STPP) Supplier South Africa

What Is Sodium Tripolyphosphate?

Sodium tripolyphosphate (STPP, sodium triphosphate) is a condensed inorganic phosphate with the formula Na₅P₃O₁₀. It is manufactured by calcination of a precise mixture of monosodium phosphate and disodium phosphate at high temperatures. STPP has long been the benchmark detergent builder, providing powerful water softening, soil anti-redeposition, and pH buffering functions in a single raw material. Although phosphate-free detergent formulations have gained ground in response to eutrophication concerns, STPP remains the standard builder in heavy-duty industrial and institutional cleaning formulations where performance takes priority.

Builder Functions in Detergent

STPP performs four critical functions in detergent formulations: it sequesters calcium and magnesium hardness ions with high affinity, preventing surfactant precipitation in hard water; it peptises and deflocculates soil particles, dispersing them in the wash liquor; it buffers solution pH in the mildly alkaline range (pH 9.5–10.5) that is optimal for surfactant performance; and it enhances enzyme stability (particularly protease) by chelating inhibitory metal ions. In powder detergents, STPP also acts as a physical conditioning agent, absorbing liquid nonionic surfactants onto its porous granule surface to improve powder flow.

Supply and Applications

Terracore Chemicals supplies detergent-grade STPP in 25 kg bags and bulk to laundry powder manufacturers, automatic dishwash detergent producers, and industrial cleaning formulators. We stock granular grades for standard formulations and can advise on dosage optimisation relative to local water hardness levels.