IP Library Granted Patent US 6,858,180
Granted Patent B2
US 6,858,180 · App. 10/147,660 · Granted Feb 22, 2005

Process for inhibiting scale

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Quick Facts
Patent No.
US 6,858,180
App. No.
10/147,660
Filed
May 16, 2002
Granted
Feb 22, 2005
Kind
B2
Art Unit
1744
USPC
422/7
Abstract

This invention relates to a process for scale inhibition using random copolymers of acrylic acid and a monomer that is hydrophobic.

Claims (11)

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.