PAINT AND/OR RUST REMOVAL COMPOSITIONS

Abstract: Cleaning composition which is particularly intended for cleaning of shipping containers, which has been formed by producing an aqueous solution of sodium or potassium hydroxide containing from 20% by weight to saturation of the alkali metal hydroxide, adding to the solution of the alkali metal hydroxide a balanced amphoteric detergent, adding to the resulting composition a liquid aromatic solvent and then adding to the resulting composition a liquid ethoxylated alcohol detergent in an amount sufficient to clarify the liquid composition. The composition also preferably has incorporated therein a rust complexing agent which is effective at high pH.

Description: TITLE PAINT AND/OR RUST REMOVAL COMPOSITIONS DESCRIPTION The present invention relates to a paint and/or rust removal composition. FIELD OF THE INVENTION Articles such as shipping containers become extremely corroded and need to be repainted at regular intervals. At the present time the corroded shipping container is typically prepared for repainting by shot blasting. There is a need for a more efficient system for preparing a corroded shipping container for repainting. Problems also arise in shipping containers where the interiors become soiled and again there is no generally satisfactory means for cleaning the soiled interiors of containers. SUMMARY OF THE INVENTION in accordance with one aspect of the present invention there is provided a composition which has been formed by producing an aqueous solution of sodium or potassium hydroxide containing from 20% by weight to saturation of the alkali metal hyrdroxide, adding to the solution of alkali metal hydroxide a balanced amphoteric detergent, adding to the resulting composition a liquid aromatic solvent and then adding to the resulting composition a liquid ethoxylated alcohol detergent in an amount sufficient to clarify the liquid composition. DESCRIPTION OF THE INVENTION The compositions of the present invention have been found particularly useful in removing paint from shipping containers. The balance amphoteric detergent may be of a type sold under the Trade Mark "Miranol" by Miranol, Inc. In particular, it has been found that "Miranol" JEM or "Miranol" C2MSF are particularly effective. The balance amphoteric detergent forms one half of a solubilising system of which the other half is the ethoxylated alcohol. The balanced amphoteric detergents are very good solubilisers in higher pH systems.- Preferably, the balanced amphoteric detergent is used in an amount from 2-5% by weight of the composition. Preferably, an amount of glycol ether is incorporated in the composition after the addition of the balanced- amphoteric detergent since this helps to solubilise the balanced amphoteric detergent. A suitable glycol ether is sold under the Trade Mark "DIOXITOL" by Shell Chemicals. The glycol ether is preferably incorporated in the composition in an amount from 1 to 15% by weight more preferably from 2 to 3% by weight of the composition. In order to render the composition of the invention capable of removing rust efficiency in addi.tion to paint it is necessary to incorporate therein a rust complexing agent such as glutamic acid or EDTA, which is effective at high pH. The rust complexing agent is preferably used in an amount from 2 to 15% by weight of the composition. The rust complexing agent is preferably added after the balance amphoteric detergent and before the liquid aromatic solvent. The liquid aromatic solvent is preferably mononuclear but it may be dinuclear. It is preferably a substituted aromatic compound. The substituents are preferably alkyl groups containing from 1 to 6 carbon atoms, more preferably 1 or 2 carbon atoms. Fox example the liquid aromatic ' solvent is preferably toluene or xylene. The liquid aromatic solvent is preferably used in an amount from 0.9:1 to 1.1:1 based on the weight of alkali metal hydroxide. The ethoxylated alcohol is preferably a 2 to 10 mole ethoxylated alcohol and is preferably used in an amount from 2 to 5% by weight of the composition. The ethoxylated alcohol may have a branched chemical structure. The composition of the present invention may be applied such as by spraying to the exterior of the articles such as shipping containers. It has been found that treatment for ^'4 hour to 2 hours is typically enough to remove paint or rust and render a shipping container suitable for repainting. Each batch of the composition can also be used a plurality of times but in this case any solids are preferably filtered out. As mentioned above it is envisaged that the composition- could be used to clean the interior of shipping containers but it is envisaged that it would .probably be used in a diluted form in this case. The present invention will now be illustrated by the following example. Example A composition in accordance with the present invention was made from a saturated aqueous solution of OH containing 46% KOH by adding to it in order 2.4% by weight of the final composition of "Miranol" JEM, 10% by weight of the final composition of glutamic acid, 2.5% by weight of the final composition of "Dioxitol" glycol ether, an amount of toluene equal in weight to the KOH, and 3% by weight of the final composition of a 6 mole ehtoxylated alcohol detergent. . The resulting composition was applied to a corroded shipping container in a system as shown in the accompanying drawing which shows a shipping container 10 mounted above a catchment tray 12 which has an outlet leading to a reservoir 14. The reservoir 14 is connected to a pump 16 which pumps compositions of the invention up to a spray 18. The spray system was used to spray a container for about one hour by which time all rust and paint had been stripped off. The steel surface of the container was ready for repriming and subsequent painting. The used composition falls into the catchment tray 12 and then via a filter into the reservoir 14. It is then available for re-use. Modifications and ' variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention.

Claims: CLAIMS 1. A cleaning composition characterised in that it has been formed by producing an aqueos solution of sodium or potassium hydroxide containing from 20% by weight to 5 saturation of the alkali metal hydroxide, adding to the solution of the alkali metal hydroxide a balanced amphoteric detergent, adding to the resulting composition a liquid aromatic solvent and then adding to the resulting composition a liquid ethoxylated alcohol detergent in an 10. amount sufficient to clarify the liquid composition. 2. A composition according to claim 1, characterised in that the balanced amphoteric detergent is used in an amount in the range from 2 to 5% by weight of the total composition. 15 3. A composition according to .claim 1 or 2, characterised in that an amount of glycol ether is incorporated in the composition after the addition of the balanced amphoteric detergent and before the addition of the liquid aromatic solvent, to help solubilise the detergent. 20 4. A composition according to claim 3, characterised in thatthe glycol ether is used in an amount in the range from 1 to 15% by weight of the total composition. 5. A composition according to claim 4, characterised in that the glycol ether is used in an amount in the range from 25 from 2 to 5% by weight of the total composition . 6. A composition according to any one of the preceding claims, characterised in that it further comprises a rust complexing agent which is effective at high pH. 7. A composition according to claim 6, characterised in 0 that the rust complexing agent is glutamic acid or EDTA. 8. A composition according to claim 6 or 7, characterised in that the rust complexing agent is used in an amount in the range from 2 to 15% by weight of the composition. 9. A composition according to any one of claims 6 to 8, 5 characterised in that the rust complexing agent is incorporated after the detergent and before the liquid aromatic solvent. 10. A composition according to any one of the preceding claims, characterised in- that the aromatic solvent is mononuclear or dinuclear. 11. A composition according to claim 10, characterised in that the aromatic solvent has an aromatic nucleus which is substituted by alkyl groups containing from 1 to 6 carbon atoms. 12. A composition according to claim 11, characterised in that the alkyl groups contain 1 or 2 carbon atoms. 13. A composition according to claim 12, characterised in that the aromatic solvent is toluene or xylene. 14. A composition according to any one of the ' preceding claims, characterised in that the liquid aromatic solvent is used in an amount from 0.9:1 to 1.1:1 based on the weight of the alkali metal hydroxide. 15. A composition according to any one of the preceding claims, characterised in that the ethoxylated alcohol is a 2 to 10 mole ethoxylated alcohol. 16. A composition according to any one of the preceding claims, characterised in that the ethoxylated alcohol is used in an amount in the range from 2 to 5% by weight of the total composition. 17. A method of making a cleaning composition, charact¬ erised in that it comprises (1) producing an aqueous solution of sodium or potassium hydroxide containing from 20% by weight to saturation of the alkali metal hydroxide, (2) adding to the composition if step (1) a balanced amphoteric detergent, (3) adding to the composition of step (2) a liquid aromatic solvent, and (4) adding to the composition of step (3) a liquid ethoxylated alcohol. detergent. 18. A method according to claim 17, characterised in that it comporises (5) adding a rust complexing agent which is effective at high pH.

Inventors: FREW JEREMY GEORGE MCKENZIE, FREW, JEREMY, GEORGE, MCKENZIE
Applicants: PROTECTIVE RESEARCH IND LIMITE, PROTECTIVE RESEARCH INDUSTRIES LIMITED
Application year: 1986
Main classification: C11D7
IPC codes: C09D9, C11D1, C11D3