Process for the preparation of polyacrylamides using an eco-friendly lubricant composition

A process for preparing water-soluble polymers in powder form by polymerization of water-soluble monoethylenically unsaturated monomers comprising the successive steps:

• a) spraying on the inner wall of the polymerization vessel the lubricant composition LC1 comprising:
• 25-40 weight % alkyl oleate/50-65 weight % polyoxyethylene oleyl ether phosphate/and 5-15 weight % sorbitan monolaurate,
• b) polymerizing in aqueous solution, in the polymerization vessel, in the presence of polymerization initiators at an initiation temperature between −20° C. and 50° C., at least one water-soluble monounsaturated ethylenic monomer, the total mass concentration of monomer relative to the polymerization charge being between 10 and 60%,
• c) discharging the polymer gel from the polymerization vessel,
• d) granulating the polymer gel thus obtained in a granulator, in presence of a lubricant composition LC2 comprising:
• 15-35 weight % alkyl oleate/15-45 weight % polyoxyethylene oleyl ether phosphate/35-55 weight % sorbitan monolaurate,
• e) drying the polymer gel to obtain a polymer in powder form, and
• f) grinding and sifting the powder.