JPH0776796A - Patina forming base material, production of the base material and formation of patina using the base material - Google Patents

Abstract

PURPOSE:To provide a patina forming base material capable of forming natural patina to be used for roofing in its early stage and to artificially form patina in the base material. CONSTITUTION:AC electrolysis is applied on the surface of a base material with at least its surface consisting of copper or copper alloy to obtain a patina forming base material on which a porous layer having many micropores with the opening 1 narrowed is formed. Patina is artificially formed in the base material. Water, moisture and patina component are easily held by the base material because of its porous surface. Accordingly, natural patina is formed in its early stage, and the patina formed in the base material is anchored in the base material surface and hardly released.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a patina-forming base material for use in roofing materials and the like in which natural patina is formed at an early stage, a method for producing the same, and an artificial material excellent in adhesion using the base material. It relates to a method of forming patina.

[0002]

[Prior Art] I often see patina formed on the copper roofs of temples. This patina is naturally formed. That is, the surface of the copper plate exposed to the air gradually oxidizes and loses its luster, and cuprous oxide and cupric oxide are generated there, and the color changes to black, reddish orange, brown or the like. As time passes, patina of the basic copper salt is formed little by little,
Eventually the entire surface is covered with patina. During the period until it is covered with patina, rainfall, temperature and humidity, atmospheric patina components, dust,
Furthermore, it is affected by bird droppings. Above all, the effects of temperature and humidity and the patina component are great. Conventional copper roofs, etc. are made from rolled copper plates, and it takes nearly 20 years to be covered with patina. Since this patina has excellent corrosion resistance and is beautiful and attractive, copper roofs have also come to be used in ordinary houses.
However, as mentioned above, it takes many years for patina to form naturally, and it is said that this year has grown further due to the recent effects of acid rain and air pollution. Thus, after many years, even if you roof the corner copper roof, it will be time to rebuild the house before the patina is formed.

Therefore, a method for artificially forming patina has been developed. This patina artificial formation method includes a method in which a copper plate or the like is anodically oxidized in an electrolytic solution to form it electrochemically (Japanese Patent Publication No. 55-12117, etc.), and a method in which it is formed by a chemical reaction in contact with a chemical conversion treatment solution. (Japanese Patent Publication No. 56-9270, etc.), a method of applying chemical conversion treatment after coating and polishing a resin coating containing copper powder (Japanese Patent Publication No. 56270).
-30396 etc.), a method of applying a paint mixed with basic copper carbonate powder which is a kind of patina (JP-A-55-139467 etc.),
There is a method of forming by applying a chemical conversion treatment liquid containing a resin (Japanese Patent Publication No. 62-19910, etc.). However, since this artificial patina has a different composition and structure from natural patina, it often peeled off within a few years. Therefore, it is difficult to maintain the aesthetic appearance for a long time.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
It has been strongly desired to develop a base material on which a natural patina is formed at an early stage or a method for forming an artificial patina which has excellent adhesion. An object of the present invention is to provide a substrate on which natural patina is formed at an early stage, a method for producing the substrate, and a method for forming patina which is difficult to peel off.

[0005]

According to a first aspect of the present invention, there is provided a base material having at least a surface made of copper or a copper alloy, and the surface of the base material is subjected to an AC electrolytic treatment. It is a base material for formation. As shown in FIG. 1, this green-blue forming substrate has a porous layer having a large number of fine pores 2 having narrow openings 1 formed on the surface thereof.

The opening has a large number of fine holes narrowed
In the fine pores of the porous layer, moisture, humidity, and
SO₂, O₂, CO₂, NO_X, SO₃ ^2-, SO_Four ^2-,
NO ₃ ^-, Cl^-The patina components such as
Natural patina (mainly basic copper sulfate, basic in some environments
Formation of complex compounds with copper chloride, basic copper carbonate, etc.)
To be done. In addition, natural patina or artificial patina formed on the base material
Becomes difficult to be peeled off by engaging with the fine holes. With this invention
AC electrolytic treatment is performed with an acid or alkaline aqueous solution, or
It is carried out in an electrolytic solution such as an organic solvent containing degrading.

The invention of claim 3 is characterized in that a base material having at least a surface made of copper or a copper alloy is subjected to an alternating current electrolytic treatment in an electrolytic solution. It is a method of manufacturing a material.

As the base material, a material such as a copper or copper alloy material and a steel or stainless steel material coated with copper is applied. The alternating current electrolytic treatment applied to the base material is performed by using the base material as one electrode and applying an alternating current in the electrolytic solution. As the AC power source, a normal 50 Hz AC power source or a power source obtained by converting this to another frequency is applied. As the electrolytic solution, any electrolytic solution capable of dissolving copper is used. For example, an acid or alkaline aqueous solution, or an ammonium salt, a copper chelating agent such as NH ₄ ⁺ , an aqueous solution of CuSO ₄ added H ₂ SO ₄ , NaCl, NH ₄ Cl, HCl or the like is used. The aqueous solution is not particularly limited by pH and solute concentration, and an aqueous solution in an alkaline region to which NH ₃ water, NaOH or the like is added may be used. However, in the neutral region, the electrolysis voltage becomes high, and the electricity cost increases, which is disadvantageous.

There are various methods for roughening the surface of a base material at least having a surface made of copper or copper alloy. Among them, the AC electrolytic treatment method is a method in which a base material just rolled is not supplied with copper ions in an electrolytic solution. Moreover, the surface can be easily roughened without being restricted by electrolysis conditions. The alternating current electrolytic treatment is a method in which the base material is alternately changed to an anode and a cathode, and electrolytic treatment is performed.When the base material is the anode, the copper layer on the surface is eluted (etched) to roughen the surface, and further the base material is the cathode. Occasionally, the eluted copper is deposited on the surface of the base material and is remarkably roughened. It is preferable to dissolve copper in the electrolytic solution in advance, because molten copper is deposited from the initial stage of the alternating current electrolytic treatment and the roughening of the surface of the base material becomes steady. This AC electrolytic treatment is efficient because the substrate can be roughened in one step. The frequency in this AC electrolysis treatment is not particularly limited, but depending on the electrolytic solution, the roughened shape changes depending on the frequency, so it must be selected.

In the present invention, when chlorine ions are contained in the electrolytic solution, roughening time is shortened and finely roughened. Furthermore, micro etching is performed in the tunnel direction in the thickness direction, and the shape becomes complicated. Due to the above-mentioned fine rough surface shape, water retention and moisture retention are improved, and S dissolved in rainwater
O ₂ , O ₂ , CO ₂ , NO _X , SO ₃ ^2- , SO ₄ ^2- , N
The patina components such as O ₃ ⁻ and Cl ⁻ are also easily trapped and retained in the micropores, and the time required for patina conversion is significantly shortened.

In the present invention, if the temperature of the electrolytic solution is maintained at 60 ° C. or lower, the formation of an oxide film is suppressed at the anode, the surface of the base material is liable to be eluted, and local dissolution progresses to cause fine etching. At the time of the cathode, the electric current concentrates on the convex portion, which becomes a burnt state, and the roughening becomes remarkable. This low temperature effect is saturated even when the temperature of the electrolytic solution is lowered below 5 ° C. Since it is expensive to cool the electrolyte, it is desirable to control the temperature of the electrolyte within the range of 5 to 60 ° C.

In the present invention, part of the copper eluted at the anode remains in the electrolytic solution without being deposited at the cathode. When the copper concentration in the electrolytic solution becomes high, the leveling property is improved, and the state becomes the same as that of ordinary copper plating, so that the roughening of the surface becomes dull. Therefore, it is preferable to control the copper concentration in the electrolytic solution to 1.0 mol / dm ³ or less.

In the present invention, when the current density during the AC electrolytic treatment is 30 A / dm ² or more, the current concentrates on the convex portion of the base material, and the local etching at the anode and the burned state at the cathode occur. Local precipitation is promoted and roughening becomes remarkable. On the other hand, when the current density exceeds 100 A / dm ² , the temperature of the electrolytic solution near the electrodes rises due to the heat of reaction and the surface roughening decreases. Therefore, the current density is 30 A / dm ² or more, 100 A / dm ²
The following is preferable.

Regarding the electrodes for the AC electrolysis treatment, the base material may be used for only one of the electrodes, but if they are used for both electrodes at the same time, the AC electrolysis treatment will be performed efficiently. When the base material is used only for one electrode, the same kind of copper material may be used for the counter electrode, or an insoluble electrode made of SUS, carbon or the like may be used. In addition, indirect power supply may be performed by passing a base material between two carbon electrodes. The indirect power supply facilitates continuous AC electrolysis treatment and is advantageous in improving productivity.

According to a first aspect of the present invention, in a method for forming patina on a base material having at least a surface made of copper or a copper alloy, the base material before patina formation is subjected to AC electrolysis treatment. .

The present invention is intended to enhance the adhesion of patina by subjecting a patina-forming substrate to an AC electrolytic treatment to roughen the surface.

In the present invention, if the surface of the base material is mechanically polished before the AC electrolysis treatment, the adhesion of patina is further improved. For mechanical polishing, ordinary polishing methods such as buff roll, brush roll, shot blast, sand blast and the like are used. When copper is electroplated on the surface of the base material whose surface has been roughened by AC electrolysis, roughening of the surface of the base material is promoted and the adhesion of patina is improved. For the electroplating of copper performed after the alternating current electrolytic treatment, a normal electroplating method using a copper sulfate bath, a copper cyanide bath, a copper pyrophosphate bath, or the like is applied. If a brightening agent is excessively added to the electroplating bath, the surface after electroplating is smoothed and the adhesion of patina is lowered, so it is necessary to stop the addition of the brightening agent in an appropriate amount.

The base material is subjected to degreasing and pickling, if necessary, before the AC electrolysis treatment. If the surface of the patina formed in the present invention is coated with a clear lacquer, the patina does not peel off even if roll forming is performed. The method of the present invention is applied to the formation of patina in various shapes or uses such as plate-like products such as roofing boards, cast products, processed and assembled products, and the effect is exhibited.

[0019]

The base material for forming patina of the present invention is a base material having at least a surface made of copper or a copper alloy, and the base material surface has been subjected to an alternating current electrolytic treatment. It is formed of a porous layer having a large number of narrow micropores.
This porous layer retains the patina component in its micropores to form patina early, and the micropores attach the patina formed to prevent the patina from peeling.

The patina-forming substrate of the present invention is easily manufactured by subjecting at least the surface of the substrate, which is made of copper or a copper alloy, to an alternating current electrolytic treatment in an electrolytic solution. During the AC electrolysis treatment, the copper layer on the surface of the base material is locally eluted at the time of anode, and the current is preferentially concentrated on the convex portion at the time of cathode, and the eluted copper is deposited. In this way, the surface of the base material is formed into a porous layer having a large number of fine pores with narrow openings.
The alternating current electrolytic treatment can be continuously performed, and the patina-forming substrate of the present invention has excellent productivity.

In the present invention, in a method of forming patina on a base material having at least the surface made of copper or a copper alloy, since the base material before patina formation is subjected to AC electrolysis treatment, the base material surface is roughened and patina is Firmly adheres to the base material.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) A rolled copper plate having a thickness of 0.4 mm was subjected to degreasing / pickling treatment and then subjected to AC electrolytic treatment to roughen the surface. Degreasing
The steps of pickling treatment, AC electrolysis treatment, and patina formation were performed under the following conditions. The rolled copper plate used was a JIS-C1100, tough pitch copper plate (65 mm x 150 mm, about 1 dm ² ) with a temper of 1 / 2H. Degreasing / Pickling treatment: Alkaline degreasing (Cleaner 160 Concentration 60
g / liter, treatment time 30 seconds, treatment temperature 60 ° C. → electrolytic degreasing (current density 3 A / dm ² ) → pickling (sulfuric acid 100 g / liter, treatment time 30 seconds, treatment temperature 20 ° C.). AC electrolysis: The composition of the electrolytic solution, the temperature, the current density (effective value), and the electrolysis time shown in Table 1 were used. AC frequency is 50H
SUS-304 was used for z and the counter electrode, and the current density was adjusted by a slide transformer.

The surface roughness Rz of the obtained green-blue forming substrate was measured, and the surface shape was observed with a scanning electron microscope.
And an air exposure test was conducted. The surface roughness was measured using a surface roughness meter manufactured by Kosaka Laboratory Ltd. As for the surface shape observed with a scanning electron microscope, the best shape from the viewpoint of moisture retention and water retention was evaluated as ⊚, and ∘, Δ, and x were evaluated in four levels. In each case, the average value of two samples was taken. The atmospheric exposure test was conducted according to the conditions of JIS-K5400. The appearance was observed every day for the first month of the beginning and every three months thereafter, and a sample of 1 cm square was cut out every six months and examined for the presence of patina by X-ray diffractometry. For comparison, the same test was performed on a tough pitch copper plate that was not subjected to AC electrolytic treatment. The number of years when the gloss of the appearance disappeared was also recorded for this comparative example product. The samples used were two types of tough pitch copper plates with different surface roughness, which were as-rolled, and three types of tough pitch copper plates, the surfaces of which were polished with a wire brush. The results are shown in Table 2.

[0024]

[Table 1]

[0025]

[Table 2]

As shown in Table 1, Nos. 1 to 22 are chlorine ion-containing aqueous solutions, and Nos. 23 to 26 are examples of the present invention which are subjected to AC electrolysis treatment using a sulfuric acid-based aqueous solution. No.27 ~
29 is a comparative example product which is not subjected to AC electrolysis treatment.

As is clear from Table 2, the age of patina formation of each of the copper plates subjected to the AC electrolysis treatment was shortened to almost half or less of that of the comparative product. The number of years covered in patina is also greatly reduced. Among them, those using an aqueous solution containing chlorine ions (Nos. 1 to 22) began to discolor immediately after outdoor exposure and uniformly turned black in less than one day. And after 2-3 years, patina formation was confirmed. High temperature aqueous solution (No.19), low current density (No.10, 11), high current density (No.14), high aqueous solution copper concentration (No. 22) and those in which the chloride ion was not contained in the aqueous solution (Nos. 23 to 26), the shape of the porous layer was slightly lacking in water retention, and the number of years of forming patina became slightly longer. Even if the liquid temperature was lowered to 1 ° C (No. 15), the effect was not recognized. From the above, it is understood that the base material for forming patina of the present invention can form natural patina at an early stage, and further effects can be obtained by limiting the composition of the aqueous solution and the electrolysis conditions.

On the other hand, the as-rolled product (No. 27, 28)
, And those roughened with a wire brush (No. 29) are
It took more than a year to lose the luster of copper, and it took 4 to 5 years to oxidize it to black. After all, it takes 12 to 13 years until the patina is partially formed, 16 before it is covered by patina.
It took more than a year.

Example 2 A rolled copper plate having the same material as that used in Example 1 and having a thickness of 0.4 mm was degreased and pickled, and then subjected to AC electrolysis to roughen the surface. Next, patina was formed on the surface of this copper plate. The degreasing / pickling treatment, AC electrolysis treatment, and patina formation were performed under the following conditions. Degreasing / Pickling treatment: Alkaline degreasing (Cleaner 160 Concentration 60
g / liter, treatment time 30 seconds, treatment temperature 60 ° C. → electrolytic degreasing (current density 3 A / dm ² ) → pickling (sulfuric acid 100 g / liter, treatment time 30 seconds, treatment temperature 20 ° C.). AC electrolysis: Electrolyte (sulfuric acid 160g / l, copper 35g /
Liter), processing time 30 seconds, processing temperature 25 ° C, 15V-50H
z energizing. Patina formation: Patina processing liquid (hydrochloric acid 15 g / l, copper acetate
75 g / liter, basic copper carbonate 50 g / liter, copper nitrate
20 g / liter, ammonium chloride 100 g / liter,
Salt: 50 g / liter). The process of spraying the treatment liquid and naturally drying was repeated twice.

(Example 3) A rolled copper plate having a thickness of 0.4 mm was sequentially subjected to shot blasting (# 150 alumina particle projection), degreasing and pickling, and then AC electrolytic treatment to roughen the surface, Thereafter, patina was formed on the surface of this copper plate.
The above-mentioned degreasing / pickling treatment, AC electrolysis treatment, and patina formation were carried out in the same manner as in Example 1.

Example 4 A patina was formed by the same method as in Example 1 except that copper was electroplated on the copper plate after the AC electrolysis treatment in a copper cyanide bath to a thickness of 0.1 μm.

Example 5 A patina was formed in the same manner as in Example 2, except that the copper plate after the AC electrolysis was electroplated with copper to a thickness of 0.1 μm in a copper cyanide bath.

(Example 6) Thickness after degreasing / pickling treatment
Copper was electroplated on a 0.4 mm rolled iron plate in a copper sulfate bath to a thickness of 0.1 mm. Next, this copper-plated iron plate was subjected to degreasing / pickling treatment under the same conditions as in Example 1, and then subjected to AC electrolytic treatment under the same conditions as in Example 1 to roughen the surface. A patina was formed on the surface of the roughened copper-plated iron plate. The above-mentioned patina formation is a patina treatment liquid (sodium carbonate 60 g / liter,
It was formed by anodizing in tartaric acid (10 g / l, sodium thiosulfate 5 g / l) for 3 minutes and then air-drying.

(Comparative Example 1) A rolled copper plate having a thickness of 0.4 mm was subjected to degreasing / pickling treatment to form patina on the copper plate. Degreasing / pickling treatment and patina formation were performed under the same conditions as in Example 1.

(Comparative Example 2) Thickness after degreasing / pickling treatment
Copper was electroplated on a 0.4 mm rolled iron plate in a copper sulfate bath to a thickness of 0.1 mm. Next, this copper-plated iron plate was shot-blasted under the same conditions as in Example 2. Then, this shot-blasted copper-plated iron plate is degreased and pickled,
Then, patina was formed under the same conditions as in Example 5.

A sample was taken from each of the patina-formed copper plate or the copper-plated iron plate thus obtained, and the patina adhesion was investigated. The patina adhesion was measured by a cross cut test. In the cross-cut test, 100 squares are formed by making cuts in a grid pattern on the patina on the sample, adhesive tape is stuck on this, and the number of squares peeled off when this adhesive tape is peeled off Was performed by the method of counting. The results are shown in Table 3.

[0037]

[Table 3]

As is clear from Table 3, in the method products of the present invention (Nos. 1 to 5), the surface of the base material on which patina was formed was roughened by AC electrolytic treatment, so that patina was firmly adhered to the base material. However, no peeling of patina was observed in any of the samples. On the other hand, in Comparative Examples Nos. 6 and 7, since the surface of the base material was smooth, patina was peeled off in a considerable portion in all cases.

[0039]

As described above, since the surface of the base material for forming green / blue of the present invention is porous, water, moisture, green / blue component, etc. are easily retained. Therefore, natural patina is formed earlier than the as-rolled base material. Further, the formed patina is attached to the porous portion, its peeling is prevented, and its appearance is maintained for a long time. The green-blue forming base material can be manufactured by continuously subjecting a long rolled base material to AC electrolysis treatment, is excellent in productivity, and is low in cost.

[Brief description of drawings]

FIG. 1 is a side view illustrating a porous layer on the surface of a patina-forming substrate of the present invention.

[Explanation of symbols]

 1 Opening 2 Micropore

Front page continuation (72) Inventor Minoru Igarashi 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (10)

[Claims] 1. A base material for forming a green-blue color, which is a base material having at least a surface made of copper or a copper alloy, and the surface of the base material has been subjected to an AC electrolysis treatment. 2. The green-blue forming substrate according to claim 1, wherein a porous layer having a large number of fine pores with narrowed openings is formed on the surface of the substrate. 3. The method for producing a base material for forming a green-blue color according to claim 1 or 2, wherein an alternating current electrolytic treatment is performed in an electrolytic solution on a base material having at least a surface made of copper or a copper alloy. 4. The method for producing a green-blue forming substrate according to claim 3, wherein the electrolytic solution contains chlorine ions. 5. The method for producing a green-blue forming substrate according to claim 3 or 4, wherein an alternating current electrolytic treatment is performed in an electrolytic solution having a temperature of 5 to 60 ° C. 6. The method for producing a green-blue forming substrate according to claim 3, wherein the electrolytic solution has a copper concentration of 1.0 mol / dm ³ or less. 7. The method for producing a green-blue forming substrate according to claim 3, wherein the alternating current electrolytic treatment is performed at a current density of 30 to 100 A / dm ² . 8. A method of forming patina on a base material having at least a surface made of copper or a copper alloy, which comprises subjecting the base material before patina formation to AC electrolytic treatment. 9. The method for forming patina according to claim 8, wherein the base material is mechanically polished before the AC electrolytic treatment. 10. The method for forming patina according to claim 8, wherein the base material is plated with copper after the alternating current electrolytic treatment.