ARTICLE AND METHOD FOR TARNISH REMOVAL

Description

[0001] This invention concerns a method for tarnish removal. 'Tarnish' is used herein to embrace discolouration or oxidation of metal surfaces. The invention is more specifically concerned with the use of an article, such as a package such as a sachet, useful in cleaning tarnish from metal objects or objects at least having a metal-plated surface. Principally the invention provides a method for removing tarnish from silver or silver-plated objects.

[0002] One known method of removing silver tarnish requires use of abrasive polish substances by manual effort. This method includes the following disadvantages:

(a) effort exerted in polishing is arduous,

(b) polishing can take a long time,

(c) intricate items such as jewellery or objects having sculptured or engraved surfaces may be impossible to polish in inaccessible areas. Conventional polish tends to get trapped in such areas and leaves an unattractive appearance, and

(d) plated items eventually lose their plated surface by the repeated action of abrasive silver polish.

[0003] DE-A-2635256 (HENKEL) discloses a sachet of sheeting, for instance of polyethylene, whose wall is designed to dispense the contents gradually, in particular a substance having an antiseptic, antistatic and/or perfuming action on linen, for instance in a drying machine. The sheeting is provided with a plurality of orifices such as holes or slots in the outlet surface arranged so as to uniformly and gradually dispense the contents of the sachet, the outlet surface having been glued or generally assembled over the whole of its area with a covering foil, e.g. an aluminium foil, which may be removed. No reference is made to any use of the sachet for removing tarnish from metal.

[0004] EP-A-0039193 (CROWN & ANDREWS) discloses a method of cleaning a tarnished metal surface, particularly silver, which comprises applying or immersing in an aqueous solution of a cleansing composition comprising a metal powder, preferably aluminium, together with a base and, optionally, a surfactant. There is, however, no disclosure of the use of an electrolyte-containing package.

[0005] It is from a consideration of drawbacks of known polishes and methods for removing tarnish that has led to the present invention.

[0006] The invention provides a method of removing tarnish from a metal or metal-plated object wherein an electrolyte-containing package is used, one surface of the package comprising water-permeable material and another surface comprising a metal sheet which is more electropositive than the object to be cleaned, to form an electrolyte solution in water, the object to be cleaned being placed in the solution in contact with the metal sheet.

[0007] Desirably, the metal sheet and water permeable material are attached together at or near the periphery of said material. The metal sheet can be in the form of gauze or foil, preferably aluminium foil, or other metal which is more electropositive than silver such as iron or zinc. Conveniently, the metal sheet may be wrapped around the package, although this is not essential for embodiments in which the surface area of the material approximates that of the sheet.

[0008] To conform with current methods of package production, the sheet can include a coating of heat sensitive adhesive substrate. It is preferred to use as water-porous material infusion web such as paper infusion web commonly employed in the production of tea bags. One side of the package may consist of the metal sheet, e.g. aluminium foil, and another may consist of infusion web appropriately stitched or adhered together at or near the periphery of the material.

[0009] Electrolyte in the form of inorganic salt may be used. This can be in powder or crystal form and the salt(s) selected may produce an alkaline solution in water. Carbonates such as sodium carbonate are preferred.

[0010] In a process in accordance with the invention for removing tarnish from the surface of a metal or metal-plated object, the said package is placed in water, preferably hot or boiling water, the electrolyte(s) is/are allowed or caused to dissolve whereupon the object is placed in the solution formed to contact the sheet. Preferably silver of silver-plated objects are used.

[0011] Use of the said package in the process provides an electrochemical means for tarnish removal wherein the object, e.g. a silver item, and a dissimilar metal are placed in an electrolyte solution such as a solution of common soda in hot water. When the two metals are in contact the tarnish is removed from the surface of the silver. Unlike an abrasive polish, silver is not physically removed in the process.

[0012] Advantages over conventional silver polish include:

(1) No effort is required in polishing, as the process is self-sustaining requiring no manual effort.

(2) The process need only take little time and may even be almost instantaneous.

(3) Tarnish can be removed from manually inaccessible areas without special procedures.

(4) Since silver metal is not physically removed from the object or its plating, plated articles may retain their plated silver surface for longer.

[0013] The article can be presented as a convenient and ready-to-use package such as a disposable sachet which includes the metal or alloy sheet either integrally or separately.

[0014] Embodiments of the invention will now be described with reference to the accompanying drawings by way of example only, wherein:

Figure 1 is a plan view of an article,

Figure 2 is a side elevation,

Figure 3 shows one form of article unfolded for use,

Figure 4 shows the article in conjunction with a receptacle of hot water,

Figure 5 illustrates ingress of water and diffusion of electrolyte,

Figure 6 illustrates tarnish removal from silver-plated objects,

Figure 7 is a view of a more preferred form of article, and

Figure 8 is a cross-section of Figure 7.

[0015] As shown in Figures 1 and 2 of the drawings, the article comprises a sheet of aluminium foil 1 together with a porous sachet 2 containing sodium carbonate (soda crystals) 3. The sachet 2 is sealed or stitched at its edges 4 and is composed of water permeable material. The sachet is also attached to the surface of the aluminium foil at 5 by, e.g. stitching or adhesive.

[0016] Figure 3 shows a sequence for unfolding the article supplied in 'package' form. The folded aluminium sheet is partially separated from the porous sachet to become opened flat into a position corresponding to Figures 1 and 2.

[0017] Referring to Figure 4, the unfolded package is placed into a receptacle 6 containing hot (preferably boiling) water 7, the water-porous material facing downwards. Water seeps into the container and the soluble electrolyte contained in the sachet diffuses into the hot water 7 to form an alkaline solution 7a of sodium carbonate referred to in Figure 5. Diffusion may take 30-60 seconds.

[0018] Use of the article is shown in Figure 6, the receptacle 6 of electrolyte solution 7a includes the aluminium foil sheet 1 fully submerged and a plurality of silver or silver-plated objects 8-13 which are in contact with themselves and/or the aluminium foil providing at least one object contacts the foil. In this process, articles according to the invention can be positively retained at the bottom of the receptacle 6 by the objects undergoing tarnish removal. Such objects rest on the aluminium foil as shown whereby at least one of them is in contact with the foil and the other objects are in metal-to-metal contact with each other and/or the foil.

[0019] Referring lastly to Figures 7 and 8, a more preferred embodiment of the invention is illustrated. The upper surface of the article comprises a non-folded sheet of aluminium foil 1 which acts as an electrode and one side of the container. The lower or under-surface is coated with a plastic, heat sensitive, adhesive 14. A sheet of infusion web 2 similar to tea bag paper forms the other side of the container. It may, if necessary, be also impregnated with heat sensitive adhesive in specific regions providing the web remains water-permeable. Such adhesives are known in the art which are active at approximately 200°C and therefore unaffected by boiling hot water.

[0020] The web 2 is heat sealed at seams 4 to the underside of the sheet 1 and consequently traps the electrolyte, light sodium carbonate powder 3, between the web 2 and the foil 1. The foil need only be coated with adhesive substrate in specific regions where the edge seams are to be formed in the web. The heat sealed seams 4 extend around the sachet formed.

[0021] In order to use such an article for tarnish removal the same steps should be taken as previously described, although there is no need to unfold the sheet initially.

[0022] Tarnish removal may require some 2 to -5 minutes. Objects with extensive tarnish may require longer and may be gently brushed to assist the action. To keep the electrochemical process sufficiently active it may be desirable to add further boiling water.

Claims

1. A method of removing tarnish from a metal or metal-plated object characterised in that an electrolyte-containing package is used wherein one surface thereof comprises water-permeable material and another surface thereof comprises a metal sheet which is more electropositive than the object to be cleaned, to form an electrolytic solution in water, and the object to be cleaned is placed in the solution in contact with the metal sheet.

2. A method as claimed in Claim 1, wherein the metal sheet and the water-permeable material of the package are attached together at or near the periphery of said water-permeable material.

3. A method as claimed in Claim 1 or Claim 2, wherein the metal sheet is in the form of a gauze or foil made of iron or zinc or aluminium.

4. A method as claimed in Claim 3, wherein the sheet is in the form of aluminium foil.

5. A method as claimed in any preceding claim, wherein the metal sheet has a coating of heat sensitive adhesive medium.

6. A method as claimed in any preceding claim, wherein the package is in the form of a sachet wherein the metal sheet and water-soluble material are stitched or adhered together.

7. A method as claimed in any preceding claim, in which the water-soluble material comprises paper infusion web.

8. A method as claimed in any preceding claim, wherein the package consists of the metal sheet and water-permeable material as respective sides thereof between which the electrolyte is contained.

9. A method as claimed in any preceding claim, in which the electrolyte comprises inorganic salt.

10. A method as claimed in Claim 9, in which the salt is in powder or crystal form.

11. A method as claimed in Claim 9 or Claim 10, in which the salt is alkaline in aqueous solution.

12. A method as claimed in any preceding claim, in which the electrolyte comprises sodium carbonate or other carbonate.

Ansprüche

1. Verfahren zum Entfernen von Anlaufschichten von einem Gegenstand aus Metall oder von einem Gegenstand mit einer Metallauflage, gekennzeichnet durch die Verwendung einer einen Elektrolyten enthaltenden Packung, die eine Fläche aus einem wasserdurchlässigen Material und eine Fläche aus einem gegenüber dem zu reinigenden Gegenstand stärker elektropositiven Metallblatt umfaßt zwecks Bildung einer Elektrolyt-Lösung in Wasser und durch Eintauchen des zu reinigenden Gegenstandes in die ElektrolytLösung unter Anlage an das Metallblatt.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Metallblatt und das wasserdurchlässige Material der Packung an oder im Bereich der Außenkanten des wasserdurchlässigen Materials miteinander verbunden sind.

3. Verfahren nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß als Metallblatt ein Metallblatt aus Eisen oder Zink oder Aluminium in Form einer Folie oder als Gaze verwendet wird.

4. Verfahren nach Anspruch 3, dadurch gekennzeichnet, daß als Metallblatt eine Aluminiumfolie verwendet wird.

5. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß als Metallblatt ein Metallblatt mit einem Überzug aus einem hitzeempfindlichen Bindemittel verwendet wird.

6. Verfahren nach einem der vorhergehenden Ansprüche, gekennzeichnet durch die Verwendung einer Packung, die die Form eines Beutels hat, bei dem das Metallblatt und das wasserlösliche Material miteinander vernäht oder verklebt sind.

7. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das wasserlösliche Material saugfähiges Papiergewebe umfaßt.

8. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Packung aus einem Metallblatt und einem wasserdurchlässigen Material als jeweilige Seitenbegrenzung besteht, zwischen denen der Elektrolyt gehalten ist.

9. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß als Elektrolyt ein unorganisches Salz verwendet wird.

10. Verfahren nach Anspruch 9, dadurch gekennzeichnet, daß unorganisches Salz in Form von Pulver oder in kristalliner Form verwendet wird.

11. Verfahren nach Anspruch 9 oder 10, dadurch gekennzeichnet, daß unorganisches Salz als Alkalilauge in wässriger Lösung verwendet wird.

12. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Elektrolyt ein Natriumkarbonat oder ein anderes Karbonat umfaßt.

Revendications

1. Procédé pour enlever la ternissure d'un objet en métal ou à placage de métal, procédé caractérisé en ce qu'on utilise un ensemble ou emballage contenant de l'électrolyte et dont une surface comprend une matière perméable à l'eau et une autre surface comprend une feuille de métal qui est plus électropositif que l'objet à nettoyer, pour former une solution d'électrolyte dans de l'eau, et l'on place l'objet à nettoyer dans la solution, en contact avec la feuille de métal.

2. Procédé tel que revendiqué à la revendication 1, dans lequel la feuille de métal et la matière, perméable à l'eau, de l'emballage sont reliées ensemble à la périphérie, ou près de la périphérie, de ladite matière perméable à l'eau.

3. Procédé tel que revendiqué à la revendication 1 ou 2, dans lequel la feuille de métal est sous forme d'une toile ou feuille mince en fer ou en zinc ou en aluminium.

4. Procédé tel que revendiqué à la revendication 3, dans lequel la feuille est sous forme d'une feuille mince en aluminium.

5. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel la feuille de métal comporte un revêtement d'un milieu adhésif thermosensible.

6. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel l'emballage est sous forme d'un sachet dans lequel la feuille de métal et la matière soluble dans l'eau sont reliées ensemble par couture ou par adhésif.

7. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel la matière soluble dans l'eau comprend une nappe de papier pour infusion.

8. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel l'emballage consiste en la feuille de métal et en la matière perméable à l'eau, qui en constituent les côtés respectifs entre lesquels l'électrolyte est contenu.

9. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel l'électrolyte comprend un sel minéral.

10. Procédé tel que revendiqué à la revendication 9, dans lequel le sel est sous forme de poudre ou de cristaux.

11. Procédé tel que revendiqué à la revendication 9 ou à la revendication 10, dans lequel le sel est alcalin en solution aqueuse.

12. Procédé tel que revendiqué dans l'une quelconque des revendications précédentes, dans lequel l'électrolyte comprend du carbonate de sodium ou un autre carbonate.

Drawing