Sodium tripolyphosphate
Effective Detergent Builder：Enhances cleaning efficiency in detergents by inhibiting scale deposition through strong chelating capacity for metal ions.
Water Softening Agent：Reduces water hardness to improve detergent performance and extend the service life of household and industrial appliances.
Food Moisture Retainer：Functions as a humectant in seafood and meat products to maintain moisture, freshness, and desired texture.
Stable Crystalline Forms：Available in multiple solid-state phases, with Phase II demonstrating the highest stability for demanding industrial applications.
Sodium tripolyphosphate (STPP, Na₅P₃O₁₀, CAS 7758-29-4) is a white crystalline phosphate salt widely employed as a detergent builder—accounting for approximately half of its global consumption—as well as a water softener and a food preservative (E451). It strongly chelates metal ions like Ca²⁺ and Mg²⁺, enhancing detergent performance by preventing scale formation. In the food industry, it acts as a moisture-retaining agent in seafood and meat products. STPP is available in three crystalline forms (Phase I, Phase II, and hexahydrate), with Phase II offering the highest stability for industrial applications.
Parameters
Melting point | 622 °C |
bulk density | 1000kg/m3 |
density | 2.52 g/cm3 (20℃) |
vapor pressure | <0.1 hPa (20 °C) |
refractive index | 1.658 |
storage temp. | Storage temperature: no restrictions. |
solubility | H2O: may be clear to slightly hazy |
form | Powder/Solid |
color | White |
Odor | Odorless |
PH | 9.0-10.0 (25℃, 1% in H2O) |
PH Range | 9.5 - 10.3 at 1 g/l at 20 °C |
Water Solubility | 20 g/100 mL (20 ºC) |
Sensitive | Hygroscopic |
Merck | 14,8697 |
Stability: | Stable. Incompatible with strong oxidizing agents, strong acids. Hygroscopic. |
InChIKey | HWGNBUXHKFFFIH-UHFFFAOYSA-I |
LogP | -4.691 (est) |
CAS DataBase Reference | 7758-29-4(CAS DataBase Reference) |
EPA Substance Registry System | Sodium tripolyphosphate (7758-29-4) |
Safety Information
Hazard Codes | Xi |
Risk Statements | 36/37/38 |
Safety Statements | 26-36-24/25 |
WGK Germany | 1 |
RTECS | YK4570000 |
F | 3 |
TSCA | Yes |
HS Code | 28353110 |
Hazardous Substances Data | 7758-29-4(Hazardous Substances Data) |
Toxicity | LD50 orally in rats: 6.50 g/kg (Smyth) |
Sodium tripolyphosphate (STPP) is widely utilized across multiple industries due to its versatile functional properties. It serves as a key ingredient in water softening, heavy-duty fabric detergents, automatic dishwashing formulations, and drilling fluid purification. In food and agriculture, it acts as a preservative for seafood, meats, poultry, and animal feeds, including liquid cattle feed supplements. Industrially, it functions as an effective peptizing, emulsifying, dispersing, and chelating agent for calcium and magnesium ions, while also stabilizing hydrogen peroxide solutions. Additionally, STPP is employed as a polyanion crosslinker in polysaccharide-based drug delivery, a sealant for leaking farm ponds, and finds applications in ceramics, leather tanning, flame retardancy, paper pulping and coatings, textile processing, ore flotation, anticorrosion pigments, and rubber production.
