From linked patent above:
" A detergent composition according to claim 5 wherein the percentages of narrow range ethoxylate nonionic detergent, soil release promoting PET-POET copolymer, builder and polyacrylate stabilizer for the PET-POET copolymer are in the ranges of 15 to 25%, 2 to 6%, 55 to 70%, and 0.5 to 5%, respectively, and the builder comprises 50 to 65% of sodium
tripolyphosphate and 2 to 10% of sodium silicate of Na2 O:SiO2 ratio of about 1:2.4, with such percentages and the Na2 O:SiO2 ratio being by weight of anhydrous material and on a final composition basis."
So it appears the phosphate version (or one of them at least) used heavy amounts of STPP as a builder, along with a small amount of sodium silicate.
Since STPP does so many jobs on wash day it really is all one needed plus some sort of surfactant (soap, or detergent) to get the job done. Add some enzymes and you've just kicked things up a notch.