CA1055801A

CA1055801A - Cleaning compositions

Info

Publication number: CA1055801A
Application number: CA229,088A
Authority: CA
Inventors: Peter Hotchkin; Rodney T. Fox
Original assignee: Reckitt and Colman Products Ltd
Current assignee: Reckitt Benckiser Healthcare UK Ltd
Priority date: 1974-06-22
Filing date: 1975-06-11
Publication date: 1979-06-05
Also published as: DK140153B; DK276575A; AU8220075A; DK140153C; GB1463719A

Abstract

Abstract of the disclosure Aqueous cleaning compositions for metal surfaces particularly copper and brass surfaces contain a soap produced by the reaction of a fatty acid with a weak base, an abrasive material and a thiosulphate, dithionite or phosphite salt.
The presence of the thiosulphate, dithionite or phosphite salt causes the composition to form a thin film of liquid on the metal surface which does not rapidly break up into droplets. A thickening and/or suspending agent may be present.

Description

~Q5i~BO~ , This invention relates to cleaning compositions for metal surfaces containing an abrasive material dispersed in a liquid medium, the major portion of which comprises water~ In particular, the invention relates to cleaning compositions for copper and brass surfaces.
It has been found that in order to be efficient, a cleaning composition for metal surfaces should exhibit the property of wetting the metal surface. The~ word "wetting" is used in this specification to describe the ability of the compositions to form a thin film of liquid on a surface which does not tend to break up to form droplets or globules xapidly and which covers the surface completely~ It is important that a cleaning composition completely covers and is in intimate contact with the surface to be cleaned in order to enable the abrasive material in the composition to burnish the surface effectively and to enable other cornponents of the composition, such as anti-tarnish agents, to act on the surface.
We have found that the inclusion of certain reducing anions in the cleaning compositions;of the present invention 20 produces an efficient clean1ng composition which shows the ~ -property of wetting copper and brass surfaces.
Cleaning compositions according to the present invention comprise an abrasive material dispersed in an aqueous liquid medium, and a surface wetting-effective amount of a thiosulphate, dithionite or phosphite salt.
The nclusion of thiosulphate, dithionite or phosphite 5~

anions results in a composition ~hich exhibits the property .
of wetting copper and brass surfaces whereas the inclusion of sulphite and hypophosphite anions in cleaning compvsikions similar to those described hereinafter does not result in adequate wetting even though the last two anions are also known reducing.agents.
The cleaning composition may also include a soap, which may be the reaction product of a fatty acid or mixture of fatty acids with ammonia or other amines. The fatty acids may be present from 0.3 to 6% by weight of the composition and the composition may contain from 0.2 to 4%
by weight of aqueous ammonia solution (specific gravity 0.880).
It i5 advantageous if the base used to form the fatty acid soap is a vol.atile base so that it evaporates to leave a film of fatty acid on the surface that has been cleaned. The presence of the soap aids the cleaning o the metal surface by provid-.ing lubrication for the abrasive material.
The abrasive material may comprise polishing earths such as fine siliceous earths and aluminas or mixtures thereof, having a particle size from 1 to 20 microns. The cleaning compositions may contain from 10 to 25~ by weight of abrasive material.
The thiosulphate, dithionite or phosphite salt may be an ~,................................................................. .

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alkali metal salt such as the sodium or potassium salt, an alkaline eartl-, metal salt such as the calcium or magnesium salt or may be the ammonium or a substituted ammonium sal t .
It is preferred that a thickening and/or suspending agent is included in the composition to minimise the deposition of the abrasive material during storage. In the absence of such a thickening and/or suspending agent~ the abrasive material quickly settles to the bottom oF the container in which the composition is stored. It is then necessary to shake the container to redistribute the abrasive material before the deaning composition is used. If the container is not shaken sufficiently to ensure that the abrasive material is evenly distributed -throughout the cleaning composition, the cleaning efficiency of the composition will not be as great as it would otherwise have been. The thickening and/or suspending agent may be bentonite, thixotropic synthetic clay, thixotropic synthetic silica or a mixture thereof. The cleaning composition may contain from O .~ to 1 0~/o by weight of the thickening and/o r suspending agent.
~ ther components may optionally be aclded to the cleaning composition. Such optionat ingredients include waxes, oils, pigments and antitarnish agents such as benzotriazole.

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A minor proportion of an organic solvent such as ethylene glycol monobutyl ether, more commonly known as butyl "Cellosolve", (Cellosolve is a Trade Mark of the Union Carbide Corporation), ethanol, white spirit~ isopropanol or a low boiling petroleum distillate such as kerosene may be used in the composition. Preferably the amount of organic solvent will not exceed 10~/o by weight of the composition.
The preferred cornpositions which contain a thickening and/
or suspending agent may be manufactured by suspending the thlckening and/or suspending agent in water, adding ~;

ammonia and a solution oF the fatty acid or acids to form the soap, adding the solid abrasive material with stirring and finally adding on aqueous solution of the reducing anion.
~lternatively the thickening/suspending agent may be suspended in water with high shear stirring. An aqueous solution of the reducing anion is then added and the mixture stirred with a paddle stirrer to form a gel . Stirring is then continued whilst the aqueous ammonia solution, a solution of fatty acid or acids and the abrasive material are added.
The following Examples illustrate the invention.

Example 1 cleaning composition was prepared containing % by w~: i ght Aqueous ammonia solution 1 .9 ;, Distilled mixed fatty acid (1) 2.7 Isopropanol 5 . o - " , , ,. ~ , , -~5~
Example 1 (cont) % by wei ght Al umina earth (> 99% Al 2 3) l O . 0 Sodium thiosulphate 1 5 pentahydrate Water 78~9 (1) The distilled mixed fatty acid is a distilled tallow fatty acid containing as major components .--16-30% Cl saturated fatty acid 15-25% C18 saturated fatty acid 40-60% Cl8unsaturated fatty acid The composition was prepared by adding the ammonia solution to a solution of the thiosulphate and then adding a solution of the mixed fatty acid in isopropanol to form a soap and then adding the alumina earth with stirring, The composition was found to remove tarnish from copper and brass surfaces and adequately wetted these surfaces whereas a simitar composition but with no sodium thiosulphate did not wet the metal surface as efficiently. The composition had to be shaken before use to redistribute the abrasive material which rapidly settled out on standing. ~.

Example 2 A cleaning composition was prepared containing -- 6 -- ;

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% by weight Synthetic thixotropic clay 1 .0 (Laponite CP - A Trade Mark of Laporte Industries) Aqueous ammonia solution1 .9 (S,G. 0.880) Distilled mixed fatty acid 2.7 (as in ~xample 1) Isop ropanol 5 . o Siliceous earth 15 0 (;~ 80% SiO2 by analysis) ~lumina earth ~ ~!1 9 ( ~ 99% A12 ~3) yellow Oxide pigment 0.1 Sodium Thiosulphate pentahydrate 1 ~5 ~;
Water 67.9 The composition was prepared by suspending the thickening and/or suspending agent (the thixotropic synthetic clay) in 75%
of the water with vigorous stirring, adding the ammonia solution and a solution of the fatty acids in isopropanol to form a soap, adding the abrasive earths and pigment with stirring and then adding a solution of the thiosulphate in the remaining water.
The composition was found to wet (that is to uniformly cover) the surface of copper and brass sheets. However~ if a composition made as above but with no sodium thiosulphate present was used the surface was not uniFormly covered.
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This indicates that the sodium thiosulphate is an essential component of the above composition to ensure adequate wetting oF the copper or brass surface to be cteaned.
composition made as in Example 2 but with no fatty acid or ammonia (which form a soap) adequately wetted copper and brass surfaces indicating that the wetting effect is not caused by the presence of the soap. The composition having no soap was not, however, suitable For use as a cleaning composition because the soap is needed to lubricate the passage of the abrasive over the surFace.

The composition of Example 2 was found to be an efficient cleaner of copper and brass surfaces. The composition was also found to clean aluminium and stainless steel surfaces but the wetting ef-fect of the thiosulphate was not however observed lS on these latter two surfaces.
Example 3 A cleaning composition was prepared containing:-% by weight Synthetic thixotropic clay 1 .0 -(Laponite CP) Thixotropic silica 1 .0 ~Silodex 24 a Trade Mark oF W~ R . Grace Ltd ) Aqueous ~mmonia solution 1 .9 (SG 0.880 Distilled mixed fatty acid tas in Example 1) 2.7 ,. : - , : , , ~
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Example 3 (cont) % t,y weight Isopropanol 5.0 Alumina earth ( > 99% ~l 2 3~ 19.8 Ammonium thiosulphate 4,0 Water 6~.6 The composition was prepared by suspending the thixotropic clay and the thixotropic silica in water (75% of total amount to be included) with vigorous stirring adding the ammonia solution and a solution of the fatty acids in isopropanol to form lO a sOap, adding the earth with stirring and adding a solution of ammonium thiosulphats in the rernaining water.
The composition was found to be an efFicient cleaner of brass and copper surfaces and to adequately wet the surface to be cleaned. However~ a composition prepared as above but 15 containing no ammonium thiosulphate did not adequately wet copper and brass surfaces.
Example ~
cleaning composition was prepared containing:

% by weight Synthetic Clay 1 .0 (Laponite CP) Thioxotropic Silica (Silodex 2~) 1 .0 ~queous ammonia solu~ion (SG 0.880) 1 .9 Olein 2.7 Isopropanol 5~0 ~ 9 _ .

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Example 4 (cdnt) % by weight Siliceous earth(~80% SiO2by analysis) 20.0 Ammonium thiosulphate 4~0 Water 64.4 The composition was prepared as in Example 3.
The composition was found to be an efficient cleaner of copper and brass surfaces and adequately wet these surfaces, ~.
A similar composition to that above but containing no ammonium thlosulphate did not adequately wet the surFace oF copper and lO , brass .
Example 5 A cleaning composition as in Example 4 was prepared having a fractionated ground-nut fatty acid in place of the olein.
This composition also adequately wetted copper and brass surfaces whereas a similar composition containing no ammonium thiosulphate did not Example 6 . ~ ~
% by weight , ~ ":
Wyoming bentonite 2.0 -Aqueous ammonia solution ~SG 0~880) 1~9 Distilled mixed fatty acid 2s7 Isop ropanol 5 . 0 > Alumina earth (> 99%A1203)4 .8 Siliceous earth ( ~ 80% SiO2by analysis) 15.0 - lo-.

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Example 6 (cont)% by weight yellow oxide pigment 0,2 Ammonium thiosulphate 4 ;0 Fl avex Oil 2 . 0 Water 62.4 The composition was prepared by the method outlined in Example 2 and was found to adequately wet copper and brass surfaces, Example 7 A c~eaning composition was prepared containing % by weight . .
Laponite CP 1 .5 Aqueous ammonia solution(SG 0,880) 1 .9 Distilled mixed fatty acid2.7 Isopropanol 5.0 Alumina earth (~99% Al2O3 ~ 10.0 Sodium thiosulphate pentahydrate 1 .5 ~ :
Water 77.4 The composition was prepared by the method outlined in Example 2 . This composition adequately wetted copper and brass surfaces.
Example 8 A composition similar to that in Example 6 was prepared . ~ :

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but containing 15% oF siliceous earth, 4.~ /0 of alumina earth and 0~2% yellow oxide pigment in place oF the alurnina earth and only 62~9% oF water This composition adequately wetted copper and brass surfaces, Example 9 A composition similar to that in Example 2 was prepared in which the sodium thiosulphate pentahydrate was replaced by ~;
sodium dithionate monohydrate.
This cornposition Qdequately wetted copper and brass surfaces.
Example 10 ~ ;
A composition similar to that in Example 2 was prepared in ;
which the sodium thiosulphate was replaced by sodium phosphite `
pentahydrate .
This composition adequately wetted copper and brass surfaces, '' . '~.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A cleaning composition for copper and brass surfaces comprising an abrasive material dispersed in an aqueous liquid medium and a surface wetting-effective amount of a reducing salt having an anion selected from the group consisting of thiosul-phate, dithionite and phosphite.

2. A cleaning composition as claimed in claim 1 also includ-ing a soap which is the reaction product of a fatty acid and a weak base.

3. A cleaning composition as claimed in claim 2 in which the soap is the reaction product of a fatty acid with an amine or ammonia.

4. A cleaning composition as claimed in claim 2 in which the composition contains from 0.3 to 6% by weight of the fatty acid.

5. A cleaning composition as claimed in claim 2 in which the weak base is ammonia and the composition contains from 0.2 to 4% by weight of aqueous ammonia solution having a specific gravity of 0.880.

6. A cleaning composition as claimed in claim 1 in which the abrasive material has a particle size from 1 to 20 microns.

7. A cleaning composition as claimed in claim 6 in which the abrasive material is selected from the group consisting of fine siliceous earth, alumina and mixtures thereof.

8. A cleaning composition as claimed in claim 7 in which the composition contains from 10 to 25% by weight of abrasive material.

9. A cleaning composition as claimed in claim 1 which additionally contains a thickening and/or suspending agent.

10. A cleaning composition as claimed in claim 9 in which the thickening and/or suspending agent is selected from the group consisting of synthetic clay, thixotropic silica, bentonite and mixtures thereof.

11. A cleaning composition as claimed in claim 1 which ad-ditionally comprises up to 10% by weight of an organic solvent.

12. A cleaning composition as claimed in claim 11 in which the organic solvent is selected from the group consisting of ethylene glycol monobutyl ether, ethanol, white spirit, isopro-panol and a low boiling petroleum distillate.