Process for inhibiting scale
View Patent ↗This invention relates to a process for scale inhibition using random copolymers of acrylic acid and a monomer that is hydrophobic.
1. A process for inhibiting the formation of calcium scale on a metal surface exposed to an aqueous system comprising:
adding from 0.1 to 1000 ppm of a random copolymer of acrylic acid and a co-monomer that has hydrophobic properties, whereby said random copolymer is synthesized in the presence of a mercapto chain transfer agent having a hydrophobic group, a solvent, and a free radical initiator, to said aqueous system containing calcium ions to which said metal surface is exposed, where the weight ratio of acrylic acid to co-monomer having hydrophobic properties, used to prepare said random copolymer, is from 2.5:1 to 10:1, and the average molecular weight of said random copolymer is from 500 to 5,000.
2. The process of claim 1 wherein the co-monomer is selected from the group consisting of 2-ethylhexyl acrylate, n-butyl acrylate, and mixtures thereof, and the mercapto chain transfer agent having a hydrophobic group is selected from the group consisting of hexyl mercaptan, lauryl mercaptan, butyl mercaptan, and mixtures thereof.
3. The process of claim 1 wherein the co-monomer is a linear mercapto compound selected from the group consisting of hexyl mercaptan, lauryl mercaptan, butyl mercaptan, and mixtures thereof.
4. The process of claim 1 wherein the co-monomer is 2-(N-ethyl perfluoro octane sulfonamide) ethyl acrylate.
5. The process of claim 1 wherein the co-monomer is a fatty acid modified maleamic acid.
6. The process of claim 1 wherein a corrosion inhibitor is used in the process.
7. The process of claim 1 wherein a surfactant is used in the process.
8. The process of claim 1 wherein an agent that inhibits microbiological growth is used in the process.
9. The process of claim 1 wherein a corrosion inhibitor, surfactant, and an agent that inhibits microbiological growth is used in the process.
10. The process of claim 1 wherein the solvent used to synthesize the random copolymer is toluene.