Process for the manufacture of high solids, free-flowing, granular poly(dimethyldiallyl ammonium chloride)

A process for the manufacture of poly(dimethyldiallyl ammonium chloride) comprising:

• (a) casting upon a continuous belt apparatus to form a film having a thickness of 1/4 inch to 1 inch an aqueous dimethyldiallyl ammonium chloride solution having a monomer concentration of at least 65 percent, by weight, monomer, said monomer solution also containing a photoreducible dye in a concentration of 1.times.10.sup.-7 to 1.times.10.sup.-4 moles per liter, a mild reducing agent in a concentration of 1.times.10.sup.-5 to 1.times.10.sup.-2 moles per liter and thermal initiator in a concentration of 1.times.10.sup.-5 to 1.times.10.sup.-2 moles per liter;
• (b) passing the solution of step (a) under a series of lights which emit visible light at an intensity of 0.1 to 10,000 foot candles and controlling the temperature of the monomer solution in the range of 5.degree. C. to 65.degree. C.;
• (c) allowing polymerization to proceed until a polymer gel is formed;
• (d) reducing the size of the polymer gel of step (c) by a size reduction means, so as to produce polymer gel particles which are less than 1 inch in their longest dimension;
• and
• (e) adding an inorganic free radical initiator selected from the group consisting of ammonium persulfate, ammonium bisulfite, potassium persulfate, sodium persulfate, potassium peroxy dicarbonate and potassium peroxy diphosphate, at a dosage of from 0.01 to 5%, by weight active initiator, based on the weight of the gel particles, to the size-reduced polymer gel particles of step (d), thereby further polymerizing the size-reduced polymer gel particles of step (d) to obtain higher conversion, and producing poly(DMDAAC) gel particles which are at least 70 percent, by weight, active polymer, readily soluble and free-flowing.