Polyphosphoric acid (PPA) is typically made by the polymerization of phosphoric acid via a thermocondensation process. The resulting PPA product has a concentration that can be as high as 118% wt expressed as H3PO4 content. PPA is composed of polymers having different chain lengths, and the composition of PPA varies with its concentration. PPA is used in a multitude of applications where mildly strong acidity and dehydration properties are needed. However, one of the drawbacks of PPA is that, as its concentration increases, its viscosity also increases.
As a result of the increased viscosity of PPA, in order to easily use PPA for many processes, PPA must be heated to a sufficient temperature to reduce its viscosity to a level that it can be more easily handled and used, for example by pumping. In some processes, however, increased PPA temperature might not be desirable. In addition, PPA is sometimes stored in plastic containers that are not able to withstand the required higher temperature to allow the PPA to be pumped.
Accordingly, it would be desirable to have a PPA composition that provides the desired PPA concentration while having a viscosity that allows easy handling at lower temperatures than required by current PPA products.