Claims
- 1. A composition for inhibiting mineral scale and corrosion of metals in the presence of water which comprises, parts based on a million parts by weight of water, from about:
- (a) 0 to 50 parts by weight of an azole,
- (b) 1.5 to 100 parts by weight of a molybdate, and
- (c) 2.0 to 100 parts by weight of at least one aminomethylene phosphonic acid or a derivative thereof selected from the group consisting of hexamethylenediamine tetra(methylene phosphonic acid) and the dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 2. The composition of claim 1 further characterized in that the molybdate is present in an amount ranging from about 3.0 to 30 parts by weight.
- 3. The composition of claim 2 further characterized in that the aminomethylene phosphonic acid and its derivatives are present in an amount ranging from about 4.0 to 50 parts by weight.
- 4. The composition of claim 3 further characterized in that the molybdate is an alkali metal molybdate.
- 5. The composition of claim 1 further characterized in that the molybdate and the aminomethylene phosphonic acid or its derivatives are present at ratios of about 0.1 to 1.0 part by weight of the molybdate to 1.0 part by weight of the aminomethylene phosphonic acid or its derivatives.
- 6. The composition of claim 5 further characterized in that the molybdate and the aminomethylene phosphonic acid or its derivatives are present in ratios of approximately 1:1.
- 7. The composition of claim 1 further characterized in that the azole is at least one triazole present in amounts ranging from about 0.1 to 30 parts by weight.
- 8. The composition of claim 3 further characterized in that the aminomethylene phosphonic acid is hexamethylenediamine tetra(methylene phosphonic acid).
- 9. The composition of claim 5 further characterized in that the molybdate is an alkali metal molybdate and the aminomethylene phosphonic acid is hexamethylenediamine tetra (methylene phosphonic acid).
- 10. The composition of claim 5 further characterized in that the aminomethylene phosphonic acid is a dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 11. The composition of claim 5 further characterized in that the aminomethylene phosphonic acid is the derivative of hexamethylenediamine tetra(methylene phosphonic acid) or the derivative of the dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 12. The composition of claim 11 further characterized in that the derivative is an alkali metal salt of hexamethylenediamine tetra(methylene phosphonic acid) or the alkali metal salt of the dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 13. The composition of claim 5 further characterized as comprising a dispersing amount of at least one water-soluble polymeric dispersing agent.
- 14. The composition of claim 13 further characterized in that the polymeric dispersing agent is a sulfonated polystyrene.
- 15. The composition of claim 13 further characterized in that the polymeric dispersing agent is a copolymer of acrylic acid and acrylamide.
- 16. The composition of claim 13 further characterized in that the polymeric dispersing agent is a combination of sulfonated polystyrene and a copolymer of acrylic acid and acrylamide.
- 17. The composition of claim 5 further characterized in that the azole is at least one triazole selected from the group consisting of benzotriazole and tolyltriazole.
- 18. The composition of claim 5 further characterized as comprising a corrosion inhibiting amount of at least one inorganic metal compound selected from the group consisting of nitrates, nitrites, silicates, carbonates and oxides.
- 19. The composition of claim 18 further characterized in that the inorganic metal compound is an inorganic metal oxide.
- 20. A process for inhibiting mineral scale and corrosion of metal in the presence of water which comprises adding to the water, parts based on a million parts by weight of water, from about:
- (a) 0 to 50 parts by weight of an azole;
- (b) 1.5 to 100 parts by weight of a molybdate; and
- (c) 2.0 to 100 parts by weight of at least one aminomethylene phosphonic acid or a derivative thereof selected from the group consisting of hexamethylenediamine tetra(methylene phosphonic acid), and the dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 21. The process of claim 20 further characterized in that the derivative is an alkali metal salt of hexamethylenediamine tetra(methylene phosphonic acid).
- 22. The process of claim 20 further characterized in that the derivative is an alkali metal salt of the dimer of hexamethylenediamine tetra(methylene phosphonic acid).
- 23. The process of claim 20 further characterized in that the aminomethylene phosphonic acid and its derivatives are present in an amount ranging from about 4.0 to 50 parts by weight.
- 24. The process of claim 23 further characterized in that the molybdate is an alkali metal molybdate present in an amount ranging from about 3.0 to 30 parts by weight.
- 25. The process of claim 20 further characterized in that the molybdate and the aminomethylene phosphonic acid or its derivatives are present at ratios ranging from about 0.1 to 1.0 part of weight of the molybdate to 1.0 part by weight of the aminomethylene phosphonic acid or its derivatives.
- 26. The process of claim 25 further characterized in that the azole is at least one triazole selected from the group consisting of benzotriazole and tolyltriazole present in amounts ranging from about 0.1 to 30 parts by weight.
- 27. The process of claim 25 further characterized in that the molybdate is an alkali metal molybdate and the aminomethylene phosphonic acid is hexamethylenediamine tetra (methylene phosphonic acid).
- 28. The process of claim 25 further characterized as comprising a corrosion inhibiting amount of at least one inorganic metal compound selected from the group consisting of nitrates, nitrites, silicates, carbonates and oxides.
- 29. The process of claim 25 further characterized in that a dispersing amount of at least one water-soluble polymeric dispersing agent is added to the water.
- 30. The process of claim 29 further characterized in that the polymeric dispersing agent is at least one polymer selected from the group consisting of sulfonated polystyrene and copolymers of acrylic acid and acrylamide.
Parent Case Info
This application is a continuation-in-part of U.S. Patent applications Ser. No. 783,646, filed Apr. 1, 1977, now U.S. Pat. No. 4,138,353, and Ser. No. 967,584, filed Dec. 8, 1978.
US Referenced Citations (11)
Related Publications (1)
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Number |
Date |
Country |
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967584 |
Dec 1978 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
783646 |
Apr 1977 |
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