Evaluation of calcium oxalate deposition on different fabrics under different sodium oxalate-based detergent formulations

Abstract

The builder is an important ingredient in detergents. Sodium oxalate is a good non-phosphate detergent builder, which has good calcium-removing properties and good wash performance in detergents. However, sodium oxalate-based detergent formulations face a tricky problem of “incrustation” on fabrics due to calcium oxalate deposition. If sodium oxalate is used in commercial detergents, then “incrustation” must be solved. In this study, we examined the effect of fabric type, anionic surfactant, polymer, and temperature on incrustation and soil redeposition (“secondary” washing effect) of a sodium oxalate-based detergent. The results showed that both the anionic surfactant and polymer influenced the deposition of calcium oxalate on fabrics. Overall, the amount of calcium oxalate deposition followed the order polyamide < polyester < cotton with the same formulation. Finally, good secondary washing effects (low ash deposition and high whiteness retention) formulations were selected by cumulative washing. The formulation of methyl ester sulfonate (MES)-sodium carboxymethyl cellulose (CMC), MES-polyvinyl pyrrolidone, and alcohol ether sulfate (AES)-CMC had better secondary effects, and the optimal combination of the 12 formulations was AES-CMC.