JP2599454B2 - Copper products with patina formed early - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a copper product in which a patina is formed at an early stage, which is used for building materials, especially for roofing materials and works of art.

[Conventional technology]

Many of the roofs, exteriors, and art ornaments of buildings such as shrines, temples, and houses are formed using copper or a copper alloy, or have a surface plated with copper. This is because copper has excellent weather resistance, is hard to corrode, and can withstand long-term action.In particular, copper has a patina on the surface, which gives the copper product a heavy and calm feeling. This is why copper is preferred as a roofing material and artwork for structures.

By the way, patina is naturally generated by exposing a copper product to the atmosphere, but its growth rate is extremely slow, and generally takes several years or more to form a desired film. It is.

For this reason, conventionally, a method of artificially generating patina by cleaning a copper product with an inorganic acid such as sulfuric acid, nitric acid or hydrochloric acid to temporarily erode the surface thereof and then treating the surface with sodium carbonate or the like. Attempted. However, the patina film produced by this method has the drawbacks that it is extremely thin, produces color unevenness, has low productivity, and requires a large-scale wastewater facility.

Therefore, as a measure to eliminate such a defect, a method of applying a paint using a copper compound of basic copper carbonate, copper sulfide or copper oxide as a fuel instead of patina on the surface of a copper product has been attempted. However, this method has much higher productivity than the above surface treatment method, but on the other hand, these coatings have very low weather resistance.For example, when this is used for a copper roof, etc., within one year, There was a drawback that the paint was peeled off and the appearance was extremely ugly.

[Means for solving the problem]

In view of this, as a result of various studies, the present invention has developed a copper product in which a patina film is formed at an early stage in which patina naturally occurs in a short period of time by accelerating the growth rate of patina generated on the surface of copper or copper alloy. It is.

That is, the copper product of the present invention is a copper product having at least a surface made of copper or a copper alloy, and the surface of the copper or copper alloy is selected from Ag, Au, C, or a platinum group that is more noble than the copper or the copper alloy. 0.1 to 100 in total
It is characterized by having 0 mg / m ² attached.

The following methods can be used as a method for adhering a substance having a noble potential. First, a method of replacing a potential noble substance on the surface of the copper product by a substitution or electroless plating. In this case, replacement plating may be performed using a plating waste liquid of a metal which is more noble than copper or a copper alloy. Next, a method of applying a potential noble substance by electroplating, a method of applying a potential noble substance in a paste form, and a method of mixing a powdery substance of a potential noble substance into a resin and applying the powder. There is a way.

[Action]

The generation of patina in the natural world occurs when CO ₂ or SO ₂ in the atmosphere dissolves in the condensed water and corrodes copper at the time of dew condensation of atmospheric moisture during rainfall or humid conditions, thereby producing patina.

At this time, a potential noble substance is attached to the surface of the copper or copper alloy, so that the copper or copper alloy forms a local battery in which the noble substance of the potential becomes the anode and the cathode becomes the cathode. Will be generated.

That is, a substance noble in potential by copper or a copper alloy, for example,
By attaching Ag, Au, C, white metal, Pb, solder, etc., the generation of patina, which is the corrosion reaction of copper, is accelerated, so that it is possible to generate patina early and naturally. Have.

Among the substances to be attached, those having a large potential difference from copper among the above substances are preferable, and Ag, Au, C, and white metal are preferable.

In addition to the methods of attachment, such as substitution, electroless plating, electrolytic plating, application of paste or application of powdery material dispersed in resin, deposition, CVD (chemical vapor deposition), PVD
Various methods such as (physical vapor phase epitaxy) can be used, but the former five are more advantageous in terms of cost and are more desirable.

As a more preferable method, there is a method of performing substitution plating by diluting and using a plating waste liquid of a metal more noble than copper, that is, a liquid obtained by exchanging washing water or a liquid in a plating bath. This is a great economic advantage.

Also desirably 0.1 to 1000 mg / m ² as the amount of deposition, 0.1 m
small acceleration patina generation rate is less than g / m ^2, 1000mg / m
^If it exceeds ² , the surface of the copper or copper alloy does not exhibit the original color of copper or copper alloy, and in addition, the corrosion of copper is pitting and it is difficult to generate patina, which is not desirable. An even more preferable amount is 0.1 to 100 mg / m ^{2 in} terms of cost.
Is good.

〔Example〕

Next, examples of the present invention will be described, but the present invention is not limited to these examples.

As shown below, inventive copper sheets No. 1 to No. 4 and comparative copper sheet No. 5 were produced.

<Copper plate of the present invention No. 1> Phosphorous deoxidized copper plate having a thickness of 0.45 mm was prepared using CN containing 0.1 g / Ag.
The copper plate was immersed in the bath for 15 seconds, and Ag was deposited on the surface of the copper plate in an amount of 10 mg / m ² .

<Copper plate No. 2 of the present invention> A 0.45 mm-thick phosphorus-deoxidized copper plate was electrolyzed as a cathode in a CN bath containing 2 g / Ag, and 30 g of Ag was added to the surface of the copper plate.
Deposited in an amount of m / m ² .

<Copper plate of the present invention No. 3> A phosphoric acid deoxidized copper plate having a plate thickness of 0.45 mm was immersed in a resin containing 1% of C powder, then pulled up and dried. It was formed with a thickness of μm.

<Copper plate No. 4 of the present invention> A phosphorous-deoxidized copper plate having a plate thickness of 0.45 mm was immersed in a solution obtained by diluting an Ag paste with a solvent, pulled up and dried, and the surface of the copper plate was coated with 90 mg / m ² of Ag. And attached.

<Comparative Copper Plate No. 5> A 0.45 mm-thick phosphorus-deoxidized copper plate was electrolyzed as a cathode in a CN bath containing 2 g / Ag, and the surface of the copper plate was coated with Ag.
Deposited in an amount of 00 mg / m ² .

The above copper sheets No.1 to No.5 were exposed to coastal areas and mountainous areas together with a 0.45 mm thick phosphor-deoxidized copper sheet (comparative copper sheet No.6), which was not subjected to any treatment, to investigate the state of patina. ,
The results are shown in Table 1.

As is clear from Table 1, all of the copper sheets No. 1 to No. 4 of the present invention generate uniform patina earlier than the comparative copper sheets No. 5 and No. 6 and over the entire surface.

〔The invention's effect〕

As described above, according to the present invention, industrially extremely remarkable effects are exhibited, such as the ability to generate uniform patina early and over the entire surface of the copper product.

Claims (1)

(57) [Claims] 1. A copper product having at least a surface made of copper or a copper alloy, wherein the copper or copper alloy has one surface selected from the group consisting of Ag, Au, C and a platinum group which is more noble than the copper or copper alloy. Alternatively, a copper product having a patina film formed at an early stage, characterized by having a total of 0.1 to 1000 mg / m ² adhered to two or more types.