Back to Catalog
Sweeteners & Food Additives

Sodium tripolyphosphate

CAS: 7758-29-4

Overview

Sodium tripolyphosphate (CAS 7758-29-4 ), commonly known as STPP or E451i , is a polyphosphate salt used across detergent manufacturing, food processing, and industrial treatment applications.

It functions primarily as a sequestrant, builder, and dispersing agent, binding calcium and magnesium ions to improve process efficiency and product performance across various sectors.

In detergent and cleaning product formulations, STPP acts as a builder that softens water by sequestering hardness ions, boosting surfactant performance in both household and industrial cleaners.

Food manufacturers use it under the E451i designation as a moisture-retention and texture agent in processed meats, seafood, and dairy products to maintain quality and yield.

Water treatment operations rely on STPP to control scale formation and disperse mineral deposits in industrial cooling and boiler systems, ensuring long-term equipment protection and efficiency.

In ceramics and paper production, it functions as a deflocculant, reducing slurry viscosity and improving material processability during the manufacturing and refining stages of production.

Sodium tripolyphosphate is supplied as a white powder or granule, with granulated forms preferred where dust control matters in bulk handling and large-scale industrial operations.

Standard commercial grades include food-grade ( FCC , E451i compliant) and technical-grade for industrial applications. Both anhydrous and hydrated forms are available for global trade.

Contact us for supply of Sodium tripolyphosphate

Physical Properties

Melting Point622 °C
Density2.52 g/cm³
Appearancewhite or colourless crystals, granules or powder
ColorWhite
OdorOdorless
FormPowder/Solid
Water Solubility20 g/100 mL (20 ºC)
Vapor Pressure<0.1 hPa (20 °C)
Refractive Index1.658
pH9.0-10.0 (25℃, 1% in H2O)
Log P-4.691 (est)

Safety & Handling

Warning GHS07 Hazard Statements H315 Causes skin irritation H319 Causes serious eye irritation H335 May cause respiratory irritation Precautionary Statements P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P271 Use only outdoors or in a well-ventilated area. P280 Wear protective gloves/protective clothing/eye protection/face protection. P319 Get medical advice/attention if you feel unwell. P321 Specific treatment (see … on this label). P405 Store locked up. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P302+P352 IF ON SKIN: Wash with plenty of water. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P332+P317 Get emergency medical help. P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help. P362+P364 Take off contaminated clothing and wash it before reuse. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code28353100
Storage Class11 - Combustible Solids
WGK (Germany)1

Other Names

E451i | sodium tripolyphosphate anhydrous | Pentasodium triphosphate | STPP | Armofos | Thermphos | Rhodiaphos LV | Thermphos N

Related Products

Chemical Properties

CAS Number
7758-29-4
EC Number
231-838-7
Mol. Weight
367.86
HS Code
28353100

Industries

Documentation