1978 年 27 巻 11 号 p. 785-792
The influence of the physico-chemical properties of the aqueous solution of a series of chelating-type polycarboxylates containing methyl groups or ethyl groups on detergencies have been studied, and compared with those of corresponding compounds without methyl or ethyl groups as well as STPP. The correlation between building performance and molecular structure has been discussed.
The detergency were tested on naturally soiled cotton patches and the detergency powers were evaluated by Scheffe's method in a detergent system formulating alkylbensenesulfonate (LAS). Measurements were made on the surface tension, the critical micelle concentration, and the emulsifying capacity of the builder solution with DBS. The buffering and dispersing capacities for carbon black and manganese dioxide in the aqueous builder solution, and the chelate stability constants of the builders with alkaline earth metals were determined.
From the results summarized in Fig, -2Fig.-4 and Table-2Table-3, it is evident that the introduction of methyl groups to ether polycarboxylates made their detergency powers and the dispersing capacities for manganese dioxide much superior to those of corresponding compounds without methyl group, but methyl groups did not affect the chelate stability considerably. And the washing performances of the builders were not correlated well with logKca values when they had the high stability values.
The effects of the methyl groups to the detergency, dispersing capacity for manganese dioxide, and chelating power were largest, when the methyl groups were bound to the carbon binding the carboxymethoxyl groups.
It seems that the ether polycarboxylate builders with logKca (logKca>3), show better washing performance when the appropriate substituents such as methyl groups are introduced to appropriate places in the compounds.