Main applications of STPP

Sodium tripolyphosphate (STPP), also known as pentasodium tripolyphosphate, sodium tripolyphosphate, and pentasodium phosphate, is an inorganic compound with the chemical formula Na5P3O10. It is a white crystalline powder, easily soluble in water, and the aqueous solution is alkaline. An amorphous water-soluble linear polyphosphate. Sodium tripolyphosphate has the functions of chelating, suspending, dispersing, peptizing, emulsifying, and pH buffering. It can be used as the main additive of synthetic detergents, industrial water softeners, leather pretanning agents, dyeing auxiliaries, and organic synthesis catalysts. , pharmaceutical industry dispersants and food additives, etc.

1. Water purification and softener: Sodium tripolyphosphate chelates metal ions with metal ions Ca2+, Mg2+, Cu2+, Fe2+, etc. in the solution to form soluble chelates, thereby reducing the hardness, and is therefore widely used for water purification. ,soften.

2. Peel softener: It can quickly soften the peel of vegetables and fruits, shorten the cooking time and improve the extraction rate of pectin and other substances.

3. Anti-discoloration agent and preservative: It can promote the decomposition of vitamin C and the fading and discoloration of pigments. It can prevent the corruption of meat, poultry and fish to extend the storage period of food.

4. Bleach protectant and deodorant: improve the bleaching effect and remove the odor in metal ions.

5. Antiseptic and bacteriostatic agent: inhibits the growth of microorganisms, thus acting as an antiseptic and bacteriostatic agent.

6. Emulsifiers, pigmented meat dispersants, anti-stratification agents, and thickeners: used to disperse or stabilize suspensions of insoluble substances in water to prevent adhesion and aggregation of suspensions.

7. Strong buffering agent and preservative: controlling and maintaining a stable pH range can make food taste more delicious. Control acidity and souring speed.

8. Water-retaining agent, softener, and tenderizer: It has an enhancing effect on protein and glomerulin, so it can increase the hydration and water-retaining properties of meat products, improve the permeability of water, promote the softening of food, improve the quality of food, and maintain Excellent flavor of food.

9. Anti-coagulant: In dairy products, it can prevent the coagulation of milk when it is heated and prevent the separation of milk protein and fat moisture.

10. Mainly used as an auxiliary for synthetic detergents, used as soap synergist and to prevent grease precipitation and blooming in bar soap. It has a strong emulsifying effect on lubricating oils and fats and can be used to adjust the pH value of buffer soaps.

Sodium tripolyphosphate is an indispensable and excellent additive in detergents. Its main functions can be summarized as follows.

① Chelating effect on metal ions

 Daily washing water generally contains hardening metal ions (mainly Ca2+, Mg2+). Not only does it increase the consumption of detergent, but it also makes the washed fabrics have an unpleasant dark gray color. Sodium tripolyphosphate has the excellent property of chelating hard metal ions, thereby eliminating the adverse effects of these metal ions.

② Improve the effects of peptization, emulsification and dispersion

 Dirt often contains human body secretions (mainly proteins and fatty substances), as well as sand, dust, etc. from the outside world. Sodium tripolyphosphate has swelling and solubilizing effects on proteins and has a peptizing effect; it can promote emulsification on fatty substances; it can disperse and suspend solid particles.

③Buffering effect

 Sodium tripolyphosphate has a large alkaline buffering effect, keeping the pH value of the washing solution at around 9.4, which is beneficial to the removal of acidic dirt.

④The function of preventing agglomeration

 Powdered synthetic detergents are hygroscopic and will cause agglomeration if stored in a place with high humidity. Clumped detergent is extremely inconvenient to use. The hexahydrate formed by sodium tripolyphosphate after absorbing water has drying properties.