ACID REMOVAL IN CLEANING PROCESSES

• US 20110100398A1
• Filed: 06/30/2009
• Published: 05/05/2011
• Est. Priority Date: 07/08/2008
• Status: Active Grant

• Current Assignee: Safechem Europe GmbH (Dow, Inc.)
• Original Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Inventors: Kuemin, Marius, Geissler, Konrad
• Granted Patent: US 8,029,623 B2
• Time in Patent Office: Days
• US Class Current: 134/10
• CPC Class Codes: B01J 41/05 in the strongly basic form
• CPC Class Codes: B08B 3/08 the liquid having chemical or dissolving effect substances used, see the relevant classes
• CPC Class Codes: B08B 3/14 Removing waste, e.g. labels, from cleaning liquid; Regenerating cleaning liquidstreatment of water in general C02F

Abstract

Embodiments of the present disclosure include cleaning processes, cleaning machines, and methods of preventing acidification of a cleaning composition in a cleaning process. The cleaning process includes contacting an article having contaminants with a cleaning composition to remove the contaminants from the article, where the cleaning composition comes to have acidic components as a result of contacting the article with the cleaning composition, and where at least 85 percent by weight, based on a total weight of the cleaning composition, of the cleaning composition is an organic solvent, collecting the cleaning composition with the contaminants and the acidic components, separating the contaminants from the cleaning composition (114), and passing the cleaning composition with the acidic components over an ion exchange resin (125) to remove the acidic components from the cleaning composition.

Claims

1. A cleaning process, comprising:

contacting an article having contaminants with a cleaning composition to remove the contaminants from the article, where the cleaning composition comes to have acidic components as a result of contacting the article with the cleaning composition, and where at least 85 percent by weight, based on a total weight of the cleaning composition, of the cleaning composition is an organic solvent;

collecting the cleaning composition with the contaminants and the acidic components;

separating the contaminants from the cleaning composition; and

passing the cleaning composition with the acidic components over an ion exchange resin to remove the acidic components from the cleaning composition.

2. The process of claim 1, where the ion exchange resin is a styrene-divinylbenzene copolymer resin.

3. The process of claim 1, where passing the cleaning composition with the acidic components over the ion exchange resin to remove the acidic components from the cleaning composition occurs continuously.

4. The process of claim 1, where the organic solvents in the cleaning composition are selected from a group consisting of alcohols, propylene glycol ethers, ethylene glycol ethers, ethylene glycol ether acetates, propylene glycol ether acetates, propylene glycol ether acetates, esters, hydrocarbons, halogenated hydrocarbons, or mixtures thereof.

5. A closed-loop cleaning machine to perform the process as described in claim 1.

6. The closed-loop cleaning machine of claim 5, where the contaminants are separated from the cleaning composition in a distillation apparatus.

7. The closed-loop cleaning machine of claim 6, where the cleaning composition passes from the distillation apparatus to an ion exchange resin located in the distillate stream downstream of the distillation apparatus, and where the ion exchange resin removes the acidic components from the cleaning composition.

11. The process of claim 1, where passing the cleaning composition with the acidic components over the ion exchange resin to remove the acidic components from the cleaning composition occurs semi-continuously.

12. The process of claim 1, where the cleaning composition is substantially free of water.

15. The closed-loop cleaning machine of claim 5, where the article is contacted with the cleaning composition in a cleaning chamber.

16. The closed-loop cleaning machine of claim 5, where the contaminants are separated from the cleaning composition in a distillation apparatus.

17. The closed-loop cleaning machine of claim 16, where the cleaning composition passes from the distillation apparatus to an ion exchange resin located in the distillate stream downstream of the distillation apparatus, and where the ion exchange resin removes the acidic components from the cleaning composition.

8. A method of preventing acidification of a cleaning composition in a cleaning process, comprising:

providing an article having contaminants on an article surface, where the contaminants are to be removed;

contacting the article surface with the cleaning composition to remove the contaminants from the article surface, where the cleaning composition comes to have acidic components as a result of contacting the article with the cleaning composition, and where more than 85 percent by weight, based on a total weight of the cleaning composition, of the cleaning composition is an organic solvent;

collecting the cleaning composition with the contaminants and the acidic components;

separating the contaminants from the cleaning composition; and

passing the cleaning composition with the acidic components over an ion exchange resin to remove the acidic components from the cleaning composition.

9. The method of claim 8, where the ion exchange resin is a strong anion exchange resin.

10. The method of claim 8, where the ion exchange resin is in OH⁻

form.

13. The method of claim 8, where the cleaning composition has a boiling point in a range of about 40 degrees Celsius to about 240 degrees Celsius.

14. The method of claim 13, where the cleaning composition has a boiling point in a range of about 90 degrees Celsius to about 200 degrees Celsius.