Continuous adiabatic inverse emulsion polymerization process

A method for continuous polymerization of ethylenically unsaturated monomers in a water-in-oil inverse emulsion under adiabatic conditions without the need for external cooling during the polymerization, the method comprising the steps of:

• (a) neutralizing a monomer composition comprising at least one water-soluble, oil-insoluble, ethylenically unsaturated acidic monomer with a base in an aqueous medium comprising water and water ice to form an aqueous monomer solution therefrom;
• (b) homogenizing the monomer solution with an oil phase in the presence of an emulsifier to form a water-in-oil inverse emulsion therefrom;
• (c) degassing the inverse emulsion;
• (d) initiating polymerization of the neutralized monomer composition after the homogenizing and degassing;
• (e) after initiating polymerization, passing the inverse emulsion through a tube reactor comprising inline static mixing elements, without cooling, at a flow rate sufficient to achieve a preselected degree of polymerization as the inverse emulsion exits the tube reactor;
• and
• (e) flash evaporating a portion of the water from inverse emulsion after it exits the tube reactor to cool and concentrate the resulting polymer-containing inverse emulsion;
• wherein during neutralization of the monomer composition, the aqueous medium comprises an amount of water ice sufficient to maintain the monomer solution at a temperature of 30° C. or less;
• and the polymerization is initiated by adding a free-radical polymerization initiator composition to the inverse emulsion prior to passing through the tube reactor.