Synthetic detergent products are increasingly becoming a necessity in people's daily life, and the development trend of modern washing determines the different requirements for decontamination, safety, environmental protection and personality of detergents. There are many types of synthetic detergents, but the important ingredients are nothing more than the following two parts: actives (ie surfactants) and detergent builders. Among them, sodium tripolyphosphate(STPP) is an excellent auxiliary agent which is indispensable in detergents.
The STPP is present in an amount of from 10 to 50% in most detergents. Its main role can be summarized as follows:
1.Chelation of metal ions: Hardening metal ions (mainly Ca2+, Mg2+) are commonly found in daily washing water. In the process of washing, they will form insoluble metal salts with the active substances in soap or detergent, which will not only increase the consumption of detergent, but also make the washed fabric have unpleasant dark grey. STPP has excellent properties of chelating hard metal ions, thus eliminating the adverse effects of these 2.metal ions.
2.Improve the role of sol, emulsification and dispersion: dirt often contains human secretions (mainly proteins and lipids), but also contains sand and dust from the outside world. STPP has the effect of swelling and solubilizing proteins, promoting emulsification of fatty substances and dispersing and suspending solid particles.
3.Buffering effect: STPP has a greater alkaline buffer effect, keeping the pH value of washing solution at about 9.4, which is conducive to the removal of acid fouling.
4.Prevention of caking: Powdery synthetic detergent has hygroscopicity. If stored in a place with high humidity, caking will occur. The use of agglomerated detergents is extremely inconvenient. The hexahydrate formed by STPP absorbed water has the characteristics of dryness. When there is a large amount of STPP in detergent formulation, it can prevent the caking phenomenon caused by moisture absorption and keep the dry and cool granularity of synthetic detergent.
