Builder (chemistry)
In addition to surfactants , builders are also ingredients of detergents that support washing performance. Originally, pentasodium triphosphate was preferred to reduce the hardness of water , i.e. to eliminate Ca and Mg ions, which lead to the formation of lime soaps . Since phosphates contribute to the eutrophication of water, mineral compounds such as zeolite A (Sasil) are used as ion exchangers today. The zeolite does not replace all functions of pentasodium triphosphate and is used e.g. B. by polycarboxylates , nitrilotriacetic acid (NTA), phosphonates , soda and / or citric acid .
Builders inhibit the formation of calcite crystals, which can damage the tissue . They also serve as a carrier (transport aid) for Ca and Mg ions to zeolite A. Depending on the degree of polymerization , polycarboxylates also have a dispersing and washing effect.
Usual contents in detergents
- 20-25% zeolites
- 5–15% soda (for the pH value of alkaline detergents)
- 2-5% polycarboxylates