Controlled release cooling additive composition

• US 20050023505A1
• Filed: 08/31/2004
• Published: 02/03/2005
• Est. Priority Date: 02/12/2001
• Status: Active Grant

• Current Assignee: Dober Chemical Corporation
• Original Assignee: Dober Chemical Corporation
• Inventors: Blakemore, Thomas J., Chen, Yu-Sen
• Granted Patent: US 7,524,434 B2
• Time in Patent Office: Days
• US Class Current: 252/176
• CPC Class Codes: C02F 1/50 by addition or application of a germicide or by oligodynamic treatment C02F1/4606, C02F1/467, C02F1/76 take precedence
• CPC Class Codes: C02F 1/68 by addition of specified substances, e.g. trace elements, for ameliorating potable water medicinal water A61K
• CPC Class Codes: C02F 2103/023 Water in cooling circuits
• CPC Class Codes: C02F 2303/08 Corrosion inhibition
• CPC Class Codes: C02F 5/00 Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents softening using ion-exchange C02F1/42
• CPC Class Codes: C09K 5/10 Liquid materials
• CPC Class Codes: Y10S 165/90 Cooling towers
• CPC Class Codes: Y10T 428/2989 Microcapsule with solid core [includes liposome]
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

A controlled-release additive composition for use in aqueous systems. The composition comprises a core containing at least one additive component and a polymeric coating encapsulating said core. The controlled released cooling additive composition slowly releases the additive components to aqueous system, thereby delivering an effective concentration level of additive components over an extended period.

Claims

1-22. -22. (cancelled)

23. A method of treating an open circulating cooling water system of a cooling tower comprising

placing a controlled release additive composition in contact with an aqueous coolant present in an open circulating cooling water system of a cooling tower,

wherein the controlled release additive composition comprises a core comprising at least one additive selected from the group consisting of corrosion inhibitors and scale inhibitors;

and a substantially insoluble coating substantially surrounding the core and effective to slow the release of the additive component into the aqueous coolant in the open circulating cooling water system.

24. The method of claim 23, further comprising adding a microbiocide to the open circulating cooling water system of the cooling tower.

25. The method of claim 24, wherein the microbiocide is an additive of the core.

26. The method of claim 23, wherein the core comprises at least one additive selected from the group consisting of phosphonates and phosphate esters.

27. The method of claim 23, wherein the core further comprises at least one additive selected from the group consisting of buffering components, defoaming agents, dispersant agents, surfactants, binding agents, die release agents, and mixtures thereof.

28. The method of claim 23, wherein the core is in a solid, granular, or particulate form.

29. The method of claim 23, wherein the coating comprises a polymeric material.

30. The method of claim 23, wherein the coating comprises a copolymer made up of units of two different monomers.

31. The method of claim 30, wherein the coating comprises a copolymer of vinylacetate and vinylversatate.

32. The method of claim 30, wherein the copolymer is made up of units from a first monomer and a second monomer different than the first monomer, the units from the first monomer constituting about 45% to about 95% by weight of the copolymer and the units from the second monomer constituting about 5% to about 55% by weight of the copolymer

33. The method of claim 23, wherein the coating of the composition is insoluble in water.

34. The method of claim 23, wherein the coating of the composition is insoluble over a temperature range of about 70 degrees Farenheit to about 150 degrees Farenheit.

35. The method of claim 23, wherein the additive composition is a pellet or tablet.

36. The method of claim 23, wherein the additive composition is placed in a filter sized to retain the insoluble coating.