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AssigneeAllied Colloids Limited
InventorsMalcolm Hawe, David Farrar
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This invention relates to aqueous acidic solutions which are thickened by cationic polymer, the polymer being added to the solution in the form of particles below 10 .mu.m in size. The useful cationic polymers are formed from a water soluble cationic ethylenically unsaturated monomer or blend of monomers comprising dialkylaminoalkylacrylics that includes a polyethylenically unsaturated cross-linking agent. A peak viscosity is achieved in the aqueous acidic solution at a particular cross-linker concentration. The concentration of cross-linking agent chosen is carefully controlled so that the viscosifying effect can be optimised whilst minimising the amount of polymer that has to be added. The amount of polymer in the aqueous acidic solution is typically in the range of from, 0.01% to 5% dry weight polymer.
An aqueous acidic solution which contains a thickening amount in the range of 0.01 to 5% by weight of a cationic polymer containing a cross linking agent wherein the polymer has been added to the solution while in the form of particles whose size down not exceed 10 .mu.m and wherein the cationic polymer is formed from polymerisable material consisting essentially of water soluble ethylenically unsaturated monomer or blend of monomers comprising 10 to 100% cationic monomer selected from the group consisting of dialkylaminoalkyl(meth)acrylates, dialkylaminoalkyl(meth)acrylamides, the acid salts thereof, and the quaternary salts thereof and polyethylenically unsaturated crosslinking agent and wherein the viscosity of the solution for any given amount of said polymer is both a function of the amount of crosslinking agent in the polymerisable material and the peak viscosity of the solution, said peak occuring when the amount of crosslinking agent is present between 5 and 45 ppm based on monomer(s), and wherein the amount of crosslinking agent in the polymerisable material is within 33% of the amount which causes the solution to have said peak viscosity.
In a process for thickening an aqueous acidic solution which comprises adding a thickening amount of a thickening agent thereto, the improvement which comprises the employment as said thickening agent of 0.01 to 5% by weight of particles of a cationic polymer formed from polymerizable material consisting essentially of water soluble monoethylenically unsaturated monomer or blend of monomers comprising 10 to 100% cationic monomer selected from the group consisting of dialkylaminoalkyl(meth)acrylates, dialkylaminoalkyl(meth)acrylamides, the acid salts thereof, and the quaternary salts thereof and polyethylenically unsaturated crosslinking agent, said particles having a size which does not exceed 10 .mu.m, said cationic polymer being such that the viscosity of the resulting solution at a given amount of said polymer is both (a) a function of the amount of crosslinking agent in the polymerizable material and (b) the amount of crosslinking agent which provides the thickened solution with its peak viscosity which amount is between 5 and 45 ppm based on monomer(s), and said crosslinking agent in the polymerizable material being within 33% of the amount that gives said peak viscosity.
Dependencies are inferred from the claim text.