DE10354527B4 - Process for patination of copper - Google Patents

Abstract

A process for patinating articles comprising copper or a copper alloy is described. The articles to be patinated are treated with a preferably aqueous patination solution which preferably contains copper ions and zinc ions and are subsequently subjected to a maturing process. This is, in particular, carried out in a temperature- and humidity-controlled chamber.

Description

The The invention relates to a method for producing a patina objects made of copper or copper alloys.

It is well known that on the surface of copper parts a greenish, forms a protective layer, among other things, when these over exposed to the weather for a long time. This layer denotes one as copper patina. In our latitudes it usually takes ten to fifteen Years, until a copper surface Completely with the green Coated layer is. For the sake of shortening This long period has been different in the past Process developed with the aim to provide a natural patina on copper surfaces imitate or cheap to create.

For example, the US-3,497,401-A a method and a reaction solution for producing a patina. At room temperature, a copper part is immersed in an acidic, aqueous solution containing potassium chlorate and copper sulfate. Also the US-5,160,381-A describes the generation of a patina on a copper object. In the multistep process described therein, 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 operation with an aqueous solution of copper carbonate, ammonium chloride, copper acetate, arsenic trioxide, copper nitrate and hydrochloric acid. Also the EP 0 943 701 A1 is concerned with the generation of a patina, again by treating a copper object with an aqueous copper salt solution. This method is particularly suitable for pre-oxidized copper surfaces.

The DE 198 09 904 A1 and the DE 4041854 A1 also have methods for producing an artificial patina to the content. According to these, an aqueous solution of copper salts is applied to a cleaned surface of a copper or copper alloy article. The objects treated in this way are subsequently used in the case of DE 198 09 904 A1 Protected from the effects of the weather. In the case of DE 4041854 A1 They are stored at a defined temperature and humidity in an air-conditioned room.

The However, known methods have a number of disadvantages. Thus, in the production of some known Patinierlösungen poisonous and harmful Components, such. B. the aforementioned arsenic trioxide used. For reasons environmental protection and health reasons, it is desirable to avoid the use of such ingredients. Other procedures have limitations in the applicability. So some procedures are generally for Patination of untreated copper surfaces less well suited, since they require pre-oxidation of the copper parts to be patinated.

Also in terms of qualitative characteristics, both optical, as well as under mechanical aspects, many let artificial generated patina layers detect deficits. Often they have insufficient adhesive properties, d. h., even under light mechanical stress bursts the artificial protective layer from.

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

These The object is achieved by the method having the features of the claim 1 solved. Preferred embodiments These methods are described in the dependent claims.

To the method according to the invention objects made of copper or of a copper alloy with a copper ion containing, preferably aqueous Patinierlösung treated and subsequently subjected to a so-called ripening process in a climatic chamber.

Of the Ripening process lines especially because he Individual ripening steps involves a selection of humidities and temperatures include. The adjustment and control of the two Parameter temperature and humidity is especially in the meant for Climate chamber well feasible.

Of the Ripening process includes the following ripening steps: After the treatment the object with the Patinierlösung, in particular the application of the patination on the object to be patinated, followed by a first resting of the article at a first resting temperature and a first Resting humidity over a first rest period. This is followed by at least one time watering the Article at a watering temperature and a watering humidity over a Wässerungsdauer, followed by a second rest at a second resting temperature and a second rest air humidity over a second rest period follows.

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 is the range between 30% and 90%, in particular between 40% and 50%, preferably (first resting air humidity). In essence, these preferred ranges for temperature and humidity given for the first rest phase also correspond to the preferred ranges for the second rest temperature and the second rest air humidity.

During the Wässerungsvorgangs the temperature in the climatic chamber is preferably between 20 ° C and 70 ° C, in particular between 25 ° C and 55 ° C. The Humidity will be during the washing process preferably held in the range between 30% to 95%, in particular in the range between 65% to 80%. Usually the watering takes place over one spray of the treated article with water. This process is preferred four to five Repeated at intervals of 90 minutes to 2 hours.

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

As already mentioned, If the patination solution used is a copper ion-containing Solution, whose preferred composition is discussed below. Next, it should be emphasized that it is particularly preferred when the object to be patinated before the application of the patination solution cleaned and / or its surface is roughened. Any existing grease or oil residues or Other contaminants on the surface may increase the adhesion of the resulting Affect patina negatively. You can meet this in particular by chemical degreasing and / or blasting of the surface to be patinated broken glass balls. Alternatively, for example, an eccentric grinder or a belt sander can be used.

Of the To be patinated object, if necessary after a described optional pre-treatment, subjected to the ripening process, preferably in the already mentioned Climate chamber convicted. It is not mandatory, but preferred that the application of the Patinierlösung in the chamber takes place.

The patination is preferably applied in finely divided form, especially preferably sprayed on. The temperature (preferably in the climatic chamber) is preferred between 30 ° C and 70 ° C, in particular it is between 40 ° C and 55 ° C. Usually the application of the patination solution takes place in at least two, preferably in four to five Treatment steps, in particular at intervals of about 1 hour.

Surprisingly was found in the Contrary to classical methods for patinating copper parts, consisting essentially of a single or repeated treatment with an aqueous copper salt solution and an adjoining one Air drying consist, the use of a ripening process, in particular in a climatic chamber, big Advantages especially with regard to the appearance and the quality of the manufactured Patina offers. The resulting artificial Patina provides a uniform and intense color impression.

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

The described method is preferred for patination of table, Band or shingles made of copper provided. However, it is in principle on all molded parts or objects made of copper or copper alloys applicable. Also Teilpatinierungen of moldings such. B. gutters are possible. So z. B. in gutters of the bead area are heavily patinated, while one the outside of the Watercourse only oxidized. This gives the visual impression the copper piece be over years and decades atmospheric Exposed to influences been. Such effects often apply the optical design of new buildings, but especially at the restoration or repair of older, listed buildings, to get the overall historical impression.

When further features possesses the method according to the invention produced patina a good resistance to mechanical stress and excellent adhesive properties.

These positive properties are also on the preferably used patination due. she consists of an aqueous solution in the a copper salt, preferably copper nitrate, in a proportion of up to to 20% by weight, in particular in a proportion of 3% by weight to 5% by weight, is included. It is preferred that in addition a zinc salt, in particular Zinc chloride is contained, preferably in a proportion of 0.1 Wt .-% to 5 wt .-%, in particular in a proportion of 0.2 wt .-% to 1% by weight. Furthermore, the solution may contain various chloride and carbonate additives, including especially sodium chloride, ammonium chloride, calcium chloride and Ammonium carbonate. The pH of the patination solution is preferably in the basic, especially in the slightly basic range at pH 7-10.

Under in the patination solution The proportion of zinc salt is particularly noteworthy. Surprisingly it was found that the zinc salt additive has a positive effect on the adhesive properties of the resulting Patina affects. In addition, such an additive causes an optical Brightening up the green.

Of the patinated object made of copper or a copper alloy is after completion of the Maturing of a green-turquoise, Copper and preferably also containing zinc ions coated patina. The patina usually shows a layer thickness of 0.02 mm to 0.06 mm, in particular of 0.03 mm to 0.05 mm, on.

Further Features of the invention will become apparent from the following examples in conjunction with the subclaims. Here you can the features and properties shown in each case alone or to several in combination with each other.

example

• – 40 g Kupfer-(II)-nitrat
• – 3 g Zinkchlorid
• – 8 g Calciumchlorid
• – 2 g Natriumchlorid
• – 20 g Ammoniumchlorid

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

• - 40 g of copper (II) nitrate
• - 3 g of zinc chloride
• - 8 g of calcium chloride
• - 2 g of sodium chloride
• - 20 g of ammonium chloride

The climate chamber has a footprint of approximately 3 × 2.5 m ² . 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, the parameters humidity and temperature are lowered again to 45% or 45 ° C. and the copper sheet is left to rest again for 3 days. This completes the patination. The copper sheet is completely evenly covered by the artificial protective layer.

Claims (13)

A process for patinating objects made of copper or of a copper alloy with a copper ion-containing, in particular aqueous Patinierlösung, wherein the article is treated with the Patinierlösung, preferably the Patinierlösung is applied to the article, and the article thus treated in a climatic chamber subjected to a so-called ripening process characterized in that the ripening process includes the following ripening steps: - a first resting of the treated article at a first rest temperature and a first rest air humidity over a first rest period, i. after the first resting, washing the treated article at least once at a wash temperature and a wash humidity over a wash duration, and ii. after at least one watering, a second resting of the treated article at a second rest temperature and a second rest air humidity over a second rest period. Method according to claim 1, characterized in that that the Resting temperatures between 20 ° C and 70 ° C, especially between 25 ° C and 55 ° C, and the quiescent humidities are between 30% and 90%, in particular between 40% and 50%. Method according to one of claims 1 or 2, characterized that the second resting temperature substantially the first resting temperature and the second rest air humidity essentially the first rest air humidity equivalent. Method according to one of the preceding claims, characterized characterized in that rinsing temperature between 20 ° C and 70 ° C, especially between 25 ° C and 55 ° C, is, and the washing humidity ranges from 30% to 95%, in particular between 65% and 80%. Method according to one of the preceding claims, characterized characterized in that first and the second rest period is each up to one week, preferably 2 to 3 days. Method according to one of the preceding claims, characterized characterized in that Wässerungsdauer up to one day, preferably 5 to 10 hours. Method according to one of the preceding claims, characterized in that a Patinierlösung is used, the at least one copper salt, preferably copper nitrate, in a proportion of 1.5 wt .-% to 20 wt .-%, in particular in egg nem content of 3 wt .-% to 5 wt .-%, contains. Method according to one of the preceding claims, characterized characterized in that a patination is used, the at least one zinc salt, preferably zinc chloride, contains. Method according to claim 8, characterized in that that the patination the zinc salt in a proportion of 0.1 wt .-% to 5 wt .-%, in particular in a proportion of 0.2% by weight to 1% by weight. Method according to one of the preceding claims, characterized characterized in that a patination is used in the chloride and carbonate additives, especially sodium chloride, Ammonium chloride, calcium chloride and / or ammonium carbonate are. Method according to one of the preceding claims, characterized characterized in that 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 up to 55 ° C, chosen becomes. Method according to one of the preceding claims, characterized characterized in that patination applied in at least two, preferably 4-5 treatment steps becomes. Method according to one of the preceding claims, characterized characterized in that the ripening process at least a surface post-treatment carried out which is selected is from the group with sealing, lightening and darkening the surface.