WO2005049889A1

WO2005049889A1 - Method for covering copper with patina

Info

Publication number: WO2005049889A1
Application number: PCT/EP2004/013009
Authority: WO
Inventors: Jürgen LEUCHTE
Original assignee: Km Europa Metal Aktiengesellschaft
Priority date: 2003-11-17
Filing date: 2004-11-17
Publication date: 2005-06-02
Also published as: US20070079906A1; PL1685273T3; CN1906328A; EP1685273B1; ES2374817T3; CY1112119T1; AU2004291674B2; EP1685273A1; CA2548291A1; SI1685273T1; DE10354527B4; KR20060107784A; CA2548291C; DK1685273T3; PT1685273E; BRPI0416664A; AU2004291674A1; JP2007511668A; ATE527396T1; DE10354527A1

Abstract

The invention relates to a method for covering copper or copper alloy articles with patina. The articles to be covered with patina are treated with a preferably copper and zinc ion-containing, preferably aqueous patination solution and are then subjected to a so-called maturation process which is especially carried out in a climatic chamber.

Description

Description Patination of copper

The invention relates to a method for producing a patina on objects made of copper or copper alloys and a Patinierlösung used in this method.

It is well known that on the surface of copper parts, a greenish, inter alia, a protective layer is formed when exposed to the weather for a long time. This layer is called copper patina. In our latitudes, it usually takes ten to fifteen years for a copper surface to be completely covered with the green layer. In order to shorten this long period, various methods have been developed in the past, with the aim of imitating or producing a natural patina on copper surfaces.

For example, US 3,497,401-A discloses a method and a reaction solution for producing a patina. At room temperature, a copper part is immersed in an acidic, aqueous solution with proportions of potassium chlorate and copper sulfate. Also US-5,160,381-A describes the generation of a patina on a copper article. In the multi-stage process described there, the copper component to be patinated is treated after purification with an aqueous solution containing copper, sodium, acetate, chlorine, sulfate, H ⁺ and OH ^' ions. After thorough cleaning and drying, the copper piece is treated in a second step with an aqueous solution of copper carbonate, ammonium chloride, copper acetate, arsenic trioxide, copper nitrate and hydrochloric acid. EP 0 943 701 A1 also deals with the invention. Generation of a patina, again by treatment of a copper object with an aqueous copper salt solution. This method is particularly suitable for pre-oxidized copper surfaces.

However, the known methods have a number of disadvantages. Thus, in the production of some known Patinierlösungen toxic and harmful components such. B. the aforementioned arsenic trioxide used. For reasons of environmental protection and health reasons, it is desirable to avoid the use of such ingredients. Other methods have limitations in applicability. Thus, some processes are generally less suitable for patining untreated copper surfaces because they require pre-oxidation of the copper parts to be patinated.

Also in terms of qualitative properties, both optical and mechanical, many artificially created patina layers show deficits. Often they have insufficient adhesive properties, i. h., even under slight mechanical stress bursts the artificial protective layer.

Accordingly, the object of the invention is to provide a method which avoids the disadvantages of the prior art and solves as many of the described problems as possible.

This object is achieved by the method having the features of claim 1. Preferred embodiments of this method are described in the dependent claims 2 to 20. Furthermore, the invention comprises the patinating solution according to the invention with the features of claim 21 and the dependent claims 22 to 24. The wording of all claims is hereby incorporated by reference into the content of this description. According to the method of the invention, articles made of copper or of a copper alloy are treated with a preferably aqueous patination solution containing copper ions and subsequently subjected to a so-called ripening process.

The ripening process is characterized in particular by the fact that it includes individual ripening steps, which include a selection of humidities and temperatures. The setting and control of the two parameters temperature and humidity can be carried out well, especially in a climate chamber provided for this purpose.

A preferred sequence of ripening steps can be summarized as follows: After treating the article with the patination solution, in particular applying the patination solution to the object to be patinated, the article is allowed to rest at a first rest temperature and a first rest air humidity over a first rest period. This is followed by at least a one-time watering of the article at a watering temperature and a watering humidity over a washing period, followed by rest again at a second rest temperature and a second rest air humidity over a second rest period.

During the first resting, the temperature, in particular in the climatic chamber, is preferably between 20 ° C and 70 ° C, in particular between 25 ° C and 55 ° C (first resting temperature). For the humidity, the range between 30% and 90%, in particular between 40% and 50%, is preferred (first resting air humidity). In essence, these preferred temperature and humidity ranges of preference for the first quiescent phase also correspond to the preferred ranges for the second quiescent temperature and the second quiescent humidity. During the washing process, the temperature in the climatic chamber is preferably between 20 ° C and 70 ° C, in particular between 25 ° C and 55 ° C. The humidity is preferably maintained in the range between 30% to 95% during the washing process, in particular in the range between 65% to 80%. Usually, the watering is done by spraying the treated article with water. This process is preferably repeated four to five times at a distance of 90 minutes to 2 hours.

The first rest period can be up to one week, but a period of two to three days is preferred. The same applies to the second rest period. The washing time is usually not more than one day, but preferably only 5 hours to 10 hours.

As already mentioned, the patination solution used is a copper ion-containing solution, the preferred composition of which is discussed below. It should further be emphasized that it is particularly preferred if the object to be patinated is cleaned before the application of the patination solution and / or its surface is roughened. Any existing grease or oil residues or other impurities on the surface can adversely affect the adhesion of the resulting patina. This is encountered in particular by chemical degreasing and / or blasting of the surface to be patinated with broken glass spheres. Alternatively, for example, an eccentric grinder or a belt sander can be used.

The object to be patinated is, optionally after a described optional pre-treatment, subjected to the ripening process, preferably transferred to the already mentioned climatic chamber. It is not mandatory, but preferred, that the application of the Patinierlösung takes place in the chamber. The patination solution is preferably applied in finely divided form, particularly preferably sprayed on. The temperature (preferably in the climatic chamber) is preferably between 30 ° C and 70 ° C, in particular it is between 40 ° C and 55 ° C. Usually, the application of the Patinierlösung takes place in at least two, preferably in four to five treatment steps, in particular at intervals of about 1 hour.

Surprisingly, it was found that, in contrast to classical see methods for patination of copper parts, which consist essentially of a single or repeated treatment with an aqueous copper salt solution and subsequent air drying, the use of a ripening process, especially in a climatic chamber, large Offers particular advantages in terms of the appearance and quality of the patina produced. The resulting artificial patina provides a uniform and intense color impression.

Optionally, a further treatment of the freshly patinated surface can be carried out. It is possible to either lighten or darken the surface. If appropriate, the surface can also be sealed, since the patina unsealed under certain circumstances may continue to react under natural weather conditions.

The described method is preferably provided for the patination of panel, strip or shingle material made of copper. However, it is applicable in principle to all moldings or articles made of copper or copper alloys. Also Teilpatinierungen of moldings such. B. gutters are possible. So z. For example, in the case of gutters, the bead area is heavily patinated, while the outside of the watercourse is only oxidized. This gives the visual impression that the piece of copper has been exposed to atmospheric influences for years and decades. Such effects are common in the optical Design of new buildings, but especially in the restoration or repair of older, listed buildings used to preserve the historic overall impression.

As other features, the patina produced by the process of the present invention has good resistance to mechanical stress and excellent adhesive properties.

These positive properties are also due to the preferably used Patinierlösung, which is also the subject of this invention. It consists of an aqueous solution in which a copper salt, preferably copper nitrate, in a proportion of up to 20 wt .-%, in particular in a proportion of 3 wt .-% to 5 wt .-%, is included. It is preferred that a zinc salt, in particular zinc chloride, is additionally present in the solution, preferably in an amount of from 0.1% by weight to 5% by weight, in particular in a proportion of 0.2% by weight. to 1% by weight. Furthermore, the solution may contain various chloride and carbonate additives, including in particular sodium chloride, ammonium chloride, calcium chloride and ammonium carbonate. The pH of the patination solution is preferably in the basic, in particular in the slightly basic range at pH 7-10.

Among the components contained in the patination solution according to the invention, the proportion of zinc salt is particularly noteworthy. Surprisingly, it has been found that the zinc salt addition has a positive effect on the adhesive properties of the resulting patina. In addition, such an addition causes a visual whitening in the green.

Finally, the invention comprises the patinated object made of copper or of a copper alloy itself (claims 25 and 26 and the dependent claims 27 and 28). After completion of the ripening process this is of a green-turquoise, copper and preferably also zinc coated with ion-containing patina. The patina usually has a layer thickness of 0.02 mm to 0.06 mm, in particular from 0.03 mm to 0.05 mm.

Further features of the invention will become apparent from the following examples in conjunction with the subclaims. In this case, the illustrated features and properties may be implemented individually or in combination with one another. example

To prepare the patination solution, the following components are dissolved in one liter of water:

- 40 g copper (II) nitrate 3 g zinc chloride 8 g calcium chloride 2 g sodium chloride 20 g ammonium chloride The climate chamber has a surface area of approx. 3 x 2.5 m. A copper sheet, the surface of which has been thoroughly sanded with an orbital sander and is free of grease and other contaminants, is placed in the climatic chamber. The temperature in the climate chamber is set to 50 ° C. At this temperature, the Patinierlösung is sprayed four times at intervals of one hour four times on the surface of the copper piece. During the following first rest period, the temperature is maintained at about 45 ° C. The humidity is regulated to about 45%. After resting for three days, a repeated watering of the treated copper part follows. A total of five times it is sprayed with water at intervals of 90 minutes. The humidity in the climatic chamber is about 75% during this period, the temperature is about 50 ° C as with the treatment with patinating solution. Subsequently If the humidity and temperature are lowered again to 45% and 45 ° C, respectively, the copper sheet is allowed to rest for 3 more days. This completes the patination. The copper sheet is completely evenly covered by the artificial protective layer.

Claims

claims

1. A method for patinating objects made of copper or a copper alloy with a copper ion-containing, in particular aqueous Patinierlösung, characterized in that the article is treated with the Patinierlösung, preferably the Patinierlösung is applied to the article, and the article thus treated a is subjected to the so-called ripening process.

2. The method according to claim 1, characterized in that selected in the ripening process temperature and humidity, preferably controlled in a climatic chamber.

3. The method of claim 1 or 2, characterized in that the ripening process includes the following ripening steps: resting the treated article at a first rest temperature and a first rest air humidity over a first rest period, at least once watering the treated article at a watering temperature and a Wässerungsluftfeuchtigkeit over a watering period, and resting the treated article at a second rest temperature and a second rest air humidity over a second rest period.

4. The method according to claim 3, characterized in that the quiescent temperatures are between 20 ° C and 70 ° C, in particular between 25 ° C and 55 ° C, and the quiescent humidities between 30% and 90%, in particular between 40%. and 50%.

5. The method according to claim 3 or 4, characterized in that the second rest temperature substantially corresponds to the first rest temperature and the second rest air humidity substantially the first rest air humidity.

6. The method according to any one of claims 3 to 5, characterized in that the washing temperature between 20 ° C and 70 ° C, in particular between 25 ° C and 55 ° C, and the Wässerungsluftfeuchtigkeit in the range of 30% to 95% , in particular between 65% and 80%.

7. The method according to any one of claims 3 to 6, characterized in that the first and the second rest period is in each case up to one week, preferably 2 to 3 days.

8. The method according to any one of claims 3 to 7, characterized in that the washing time is up to one day, preferably 5 to 10 hours.

9. The method according to any one of the preceding claims, characterized in that the patination solution at least 1 copper salt, preferably copper nitrate, in a proportion of 1, 5 wt .-% to 20 wt .-%, in particular in a proportion of 3 wt .-% to 5% by weight.

10. The method according to any one of the preceding claims, characterized in that the patination solution contains at least one zinc salt, preferably zinc chloride.

11. The method according to claim 10, characterized in that the patination solution, the zinc salt in a proportion of 0.1 wt .-% to 5 Wt .-%, in particular in a proportion of 0.2 wt .-% to 1 wt .-%, contains.

12. The method according to any one of the preceding claims, characterized in that chloride and carbonate additives, in particular sodium chloride, ammonium chloride, calcium chloride and / or ammonium carbonate, are contained in the Patinierlösung.

13. The method according to any one of the preceding claims, characterized in that prior to the treatment of the article at least one surface pretreatment is carried out, which is selected from the group with cleaning and roughening the surface.

14. The method according to claim 13, characterized in that the cleaning is a degreasing, in particular a chemical degreasing, is.

15. The method according to claim 13 or 14, characterized in that the roughening is a grinding or a jet treatment, in particular glass sandblasting.

16. The method according to any one of the preceding claims, characterized in that the Patinierlösung applied in finely divided form, in particular sprayed.

17. The method according to any one of the preceding claims, characterized in that when treating the article with the Patinierlösung a treatment temperature in the range of 30 ° C to 70 ° C, in particular in the range of 40 ° C to 55 ° C, is selected.

18. The method according to any one of the preceding claims, characterized in that the Patinierlösung in at least two, preferably 4 - 5 treatment steps is applied.

19. The method according to any one of the preceding claims, characterized in that after the ripening process at least one surface treatment is performed, which is selected from the group of sealing, brightening and darkening of the surface.

20. The method according to any one of the preceding claims, characterized in that the object to be patinated is selected from the group of sheet material, strip material, molding and ornament.

21 Patinierlösung for patination of objects made of copper or a copper alloy in the form of a preferably aqueous copper salt solution, characterized in that the solution contains zinc ions.

22 Patinierlösung according to claim 21, characterized in that it contains a zinc salt, in particular zinc chloride, preferably in a proportion of 0.1 wt .-% to 5 wt .-%, in particular from 0.2 wt .-% to 1 wt .-%.

23. patination solution according to claim 21 or 22, characterized in that at least 1 copper salt, preferably copper nitrate, in a proportion of 1, 5 wt .-% to 20 wt .-%, in particular from 3 wt .-% to 5 wt .-%. %, is included.

24. patination solution according to any one of claims 21 to 23, characterized in that chloride and carbonate additives in the solution in particular sodium chloride, ammonium chloride, calcium chloride and / or ammonium carbonate.

25. Patinated article made of copper or of a copper alloy, producible by a process according to one of claims 1 to 20.

26. A patinated article made of copper or of a copper alloy, produced by a process according to any one of claims 1 to 20 before.

27. Patinated article made of copper or a copper alloy according to claim 25 or 26, characterized in that it is constructed as follows: - a base made of copper or a copper alloy selected from the group of sheet material, strip material, molding and ornament and at least a patina layer containing copper and zinc ions on the body.

28. Patinated article according to one of claims 25 to 27, characterized in that the thickness of the patina 0.02 to 0.06 mm, in particular 0.03 to 0.05 mm.