From the equilibrium sorption data which are available, it seems logical to expect that polyphosphate ions would be strongly sorbed on the surface of the dirt (especially clay soils) so as to give it a greatly increased negative charge. The charged particles then repel each other and are also repelled from the charged surface, which almost invariably bears a negative charge under washing conditions. The negatively charged dirt particles then leave the surface and go into the aqueous phase. This hypothesis is evolved in analogy to the demonstrated action of organic actives in detergency. It does not consider the kinetic effects of the phosphate builders on sorption desorption phenomena which will be discussed later (see pp. 1746 -- 1748).

The crude picture of the detergency process thus far developed can be represented as: ** f The influence of mechanical action on the particles of free soil may be compared to that of kinetic energy on a molecular scale. Freed soil must be dispersed and protected against flocculation. Cleaned cloth must be protected against the redeposition of dispersed soil. It is evident that the requirements imposed by these effects upon any one detergent constituent acting alone are severe.

Upon consideration of the variety of soils and fabrics normally encountered in the washing process, it is little wonder that the use of a number of detergent constituents having ``synergistic'' properties has gained widespread acceptance. In the over-all process, it is difficult to assign a ``pure'' role to each constituent of a built detergent formulation; and, indeed, there is no more reason to separate the interrelated roles of the active, builder, antiredeposition agent, etc. than there is to assign individual actions to each of the numerous isomers making up a given commercial organic active.