JPH04193961A - Formation of patina - Google Patents

Abstract

PURPOSE:To form patina excellent in adhesion by subjecting a copper thin film formed by electrodeposition on the surface of a substrate to treatment by a treating soln. obtd. by mixing a soln. contg. aluminum chloride with an oxidizing agent. CONSTITUTION:A copper thin film is formed on the surface of a substrate on which patina shall be formed, and after that, the above thin film is treated by a treating soln. obtd by mixing a soln. contg. aluminum chloride with an oxidizing agent. In this way, greenish blue having an almost same deep color tone as that of natural one and extremely excellent in adhesion can stably be formed in a short time on every kinds of substrates. This can be formed on the spot because special equipment or the like are not required, and it is applicable in a wide field not only for roof materials but also for building inner wall materials, ornaments or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for stably forming a patina with excellent adhesion to a substrate with good productivity.

<Conventional technology and its challenges> Over the years, the surface of copper, which has been used for the roofing of shrines and temples, has been exposed to oxygen and water vapor in the atmosphere.

An elegant and beautiful green patina (CuCO2/Cu(OH)z) due to the action of carbon dioxide gas, sulfides or chlorides.

Cu S Oa・3 Cu(OH)z, CuC1z・
3 It is well known that the material is covered with basic copper salts such as Cu(OH)2, but this patina layer not only creates a profound and unique aesthetic appearance, but also acts as an anticorrosive film, and therefore The patina-covered copper roofs will last for hundreds of years.

Therefore, in recent years, "patina film-forming products" that artificially generate a natural-looking patina in a short period of time to prevent corrosion of base materials and have decorative or artistic effects have been developed, which can be used not only for roofing materials but also for interior wall materials in buildings. It has come to be seen in ornaments, etc., and many proposals have been made to date on means of artificially forming a patina that is close to natural.

These conventional artificial patina formation means can be broadly classified as follows.

(A) Chemical conversion treatment method in which contact is made with a chemical solution (for example,
-51468, etc.).

(B) Method of electrolytic treatment in a chemical solution (for example,
12117, etc.).

(C) A method in which a base material is subjected to a chemical conversion treatment and then a coating is applied thereon (for example, the method proposed in JP-A-55-8491).

(D) A method of painting with a paint containing a green-blue-forming substance (for example, the method proposed in JP-A-55-139467).

(E) A method in which copper or copper alloy powder is bonded with an adhesive to the surface of a copper plate whose surface has been roughened by sandblasting, and then an artificial patina-generating liquid such as ammonium chloride or ammonium sulfate is applied (for example, Japanese Patent Publication No. 57-52425 methods proposed as such).

However, the above-mentioned artificial patina formation means are practically a) The rate of development of patina is slow.

b) The patina coating is easy to peel off, and manufacturing equipment costs a lot of money.

C) Unable to stably form green-blue color, resulting in non-uniformity and poor color tone.

d) Poor adhesion of patina.

e) Many man-hours are required to form the green-blue coating, resulting in poor productivity.

Problems such as these have been pointed out, and furthermore, the base material is generally limited to copper or copper alloy, and if the patina surface is not protected by painting etc. There was also the problem that sufficient adhesion could not be maintained. Moreover, the protection of patina by using a paint film cannot provide a fundamental solution to the above problem because the paint film composition deteriorates due to ultraviolet rays.

Therefore, the purpose of the present invention is to stably form a patina film with excellent adhesion and uniform color tone in a short time regardless of the type of substrate and without requiring special equipment. The aim was to establish a relatively inexpensive means of obtaining 1.

Means for Solving the Problems> As a result of intensive research from various viewpoints in order to achieve the above object, the present inventors have found that: a) copper or copper alloy is added to the surface of the substrate on which patina is to be formed; When a thin film made of copper or a copper alloy is formed and then the thin film is treated with a "specific new chemical conversion treatment solution containing an oxidizing agent," A chemical conversion reaction (corrosion product formation reaction) and an oxidation reaction of the corrosion products proceed simultaneously with the treatment solution, resulting in a thick and solid surface that adheres firmly to the surface of the substrate and closely resembles a natural patina. A patina film with a uniform tone is formed in a short time.

b) If electrodeposition is used as a means of forming a thin film made of copper or copper alloy on the surface of a substrate, no special equipment is required to form the thin film, and the substrate can be easily handled. Not only is this advantageous in terms of cost, but also the adhesion of the patina produced can be further improved by adjusting the electrodeposition conditions.

We were able to obtain this knowledge.

The present invention was completed based on the above-mentioned findings, etc., and is based on the following: ``After a thin film made of copper or copper alloy is electrodeposited on the surface of a base material on which patina is to be formed, the thin film is ) Addition of aluminum powder to alkali metal chloride and/or alkaline earth metal chloride.

(1+) Aluminum chloride.

(c) Tinnic chloride.

(d) Zinc chloride.

(By treating with a treatment solution containing one or more types selected from lead chloride and an oxidizing agent, it is possible to stably form a patina with excellent adhesion and a good appearance in a short time. It is characterized by the fact that

Here, the "base material on which patina is to be formed" is not limited to metal materials such as copper and copper alloys, but may also be ceramics, roof tiles, wood 3 synthetic resins, etc.
The material is not particularly limited. However, if the base material is not a metal material, it must be pretreated to form a "thin film made of copper or copper alloy" by electrodeposition, such as by making it conductive by a known method such as electroless plating or sputtering. Needless to say, it is necessary to perform some processing.

Hereinafter, the present invention will be explained in more detail and concretely along with its functions and effects.

In the patina forming method according to the present invention, a "thin film made of copper or copper alloy" is first formed on the surface of the base material by electrodeposition. Although the thickness of the thin film is not particularly limited,
Usually it is about 1 to 100 μs, preferably about 5 to 40 μs. Of course, it is possible to form a patina even if the film thickness is less than 1 gn, but in this case it is not preferable because cracks are likely to occur in the thin film. On the other hand, if the film thickness exceeds 100 mm, it becomes difficult to obtain a satisfactory color tone and is also unfavorable in terms of production cost.

In addition to electrodeposition, vacuum evaporation, sputtering, ion blasting, thermal spraying, and other methods are known as means for forming a metallic thin film on the surface of a substrate. Thus, special equipment is not required when forming a thin film made of copper or copper alloy. 1. [The base material is easy to handle].

[In addition to having advantages such as J, which is advantageous in terms of cost, it is extremely advantageous because the adhesion of the patina that is subsequently produced can be further improved by adjusting the electrodeposition conditions.

In addition, in order to form a "copper or copper alloy thin film" by electrodeposition according to the present invention, for example, a known "acidic copper sulfate bath" is used.
Or electrolyte composition such as "alkaline copper cyanide bath",
It is possible to simply apply the electrolytic conditions as they are, but if possible, it would be better to use the electrolytic copper plating method proposed earlier by the present applicant (Patent Application No.
232866), i.e. current density near 5A
/dm or higher, and the flow rate of the plating solution is 1 m/sec or higher (current density is about 100 A/dtri,
It is desirable to electrodeposit the "copper or copper alloy thin film" at a plating solution flow rate of about 1.5 m/sec (more preferably about 1.5 m/sec). This is because when a "copper or copper alloy thin film" is electrodeposited under the above conditions, the adhesion of the patina produced by subsequent processing becomes even better, making the patina layer firmly adhered to the base material more stable. This is because it can be formed into

The surface roughness of the "thin film made of copper or copper alloy" itself formed on the base material is not particularly limited. On the other hand, if the thickness exceeds 50a++, the adhesion strength between the base material and the thin film tends to decrease.
-50 rhinoceros, preferably 5-40 rhinoceros.

By the way, "thin film made of copper or copper alloy" on the surface of the base material
Roughening the surface of the base material prior to the formation of the coating improves the adhesion between the base material and the "thin film made of copper or copper alloy", and thus the adhesion of the patina coating to be formed. This is extremely desirable. Therefore, before forming a thin film made of copper or copper alloy, the surface of the base material is roughened as necessary to roughen the base material surface and temporarily activate the surface. is planned.

Generally, two types of methods for roughening the surface of a substrate are known: a chemical method (including an electrochemical method) and a physical method (mechanical method). Examples of the former include immersion in acid or alkali (i.e., etching method) and electrolysis, and examples of the latter include blasting, water jet, and moving crab method. ”, “Hand tool method”
etc. can be mentioned. Therefore, when roughening the surface of the base material prior to forming the "thin film made of copper or copper alloy" according to the present invention, the roughening method depends on the type of the base material and the roughness of the desired patina-forming surface. must be selected appropriately. For example, when the base material is a metal material, the surface of the base material can be roughened with high efficiency, and at the same time, rust and other corrosion products generated on the base material surface can be removed. It can be said that "blasting method" is suitable.

In addition, in the blasting method, abrasive materials with various hardness levels such as silica sand, steel grisodes, steel grindstones, fused alumina (artificial corundum), alundum, carborundum, glass beads, synthetic resin particles, etc. can be used as abrasive materials. is used, so it is possible to select a suitable one according to the type of base material etc.
Another advantage is that the surface roughness can be adjusted by changing the blasting conditions.

In addition, blasting methods are classified into types from various viewpoints. For example, from the viewpoint of the method, spraying of abrasive materials can be classified into "method of blasting using compressed air" and "method of blasting using centrifugal force." Furthermore, depending on the dry and wet state of the abrasive to be sprayed, it can be classified into "dry method" and "wet method", but in the present invention, there are no particular restrictions on the types or combinations thereof.

The surface roughness of the base material after the surface roughening treatment is preferably 3 degrees or more, preferably 10 to 30 gfl+. This is because if the surface roughness is less than 3rm, it is a thin film made of copper or copper alloy.
This is because the effect of improving adhesion between the two is not significant. on the other hand,
If the surface roughness exceeds 50 -, although the adhesion will be good, it is not realistic as distortion occurring in the base material may become a problem.

Now, in the present invention, after a "thin film made of copper or a copper alloy" is electrodeposited on the surface of a base material, the thin film is coated with a "specific novel material containing an oxidizing agent," which is one of the major features of the present invention. oxidation treatment of the chemical conversion treatment film that is generated along with the chemical conversion treatment is performed simultaneously.

In general, "chemical conversion treatment" involves chemically reacting the metal with a corrosive solution (chemical treatment solution) adjusted to specific conditions to form a layer of water-insoluble corrosion products that stick to the surface of the metal. Rust prevention is a process that utilizes the physical or chemical properties of corrosion products.

It has been widely used as a lubrication base for painting base 3 composition processing.

The "treatment with a specific treatment liquid" according to the present invention has almost the same concept as the above-mentioned "chemical conversion treatment," but in the present invention, in particular, the "treatment with a specific treatment liquid" that is made of "copper or copper alloy" electrodeposited on a base material is It can also be said to be unique in that it forms a distinctive patina by treating the "thin film" with a treatment solution different from that used in ordinary chemical conversion treatments.

As mentioned above, the special treatment liquid used in the present invention is (a) a solution prepared by adding aluminum powder to an alkali metal chloride and/or an alkaline earth metal chloride.

(b) Aluminum chloride.

(c) 1 stannic chloride (d) Zinc chloride.

(f) An oxidizing agent is added to a solution containing one or more types selected from lead chloride (the solvent is generally water, but a solvent other than a water plate may be used). Furthermore, it is also possible to add substances called "green-blue whole herbal medicines" such as alum, copper sulfate, copper nitrate, etc., and the present invention includes all of these. The oxidizing agent added to the treatment liquid according to the present invention is not particularly limited, but includes, for example, a) manganese dioxide (MnO□).

b) Lead dioxide (PbO2).

C) Permanganate (KMn○4+ NaMn0a, etc.).

d) Chromates and/or dichromates (also including chromic acid and dichromic acid).

e) It is preferable to use an iodine compound containing free iodine (for example, an iodopotassium solution containing free iodine) alone or in combination.

Note that (a) aluminum powder is added to the alkali metal chloride and/or alkaline earth metal chloride.

(o) Aluminum chloride.

(c) Tinnic chloride.

(d) Zinc chloride.

(n) A solution containing one or more selected from lead chloride, or a solution to which a "green-blue crude drug" such as alum, copper sulfate, copper nitrate, etc. is added (hereinafter, these solutions will be referred to as "the chemical compound of the present invention"). When the treatment liquid comes into contact with the thin film made of copper or copper alloy, it reacts with it to produce cuprous chloride (CuC1), or it reacts with each other on or within the thin film. to produce cuprous chloride.

In the present invention, a thin film made of copper or a copper alloy formed on a base material is treated with a treatment solution prepared by appropriately combining the chemical conversion treatment solution of the present invention and an oxidizing agent, and the chemical conversion reaction and oxidation reaction are simultaneously carried out. It is allowed to progress to form a patina.

Hereinafter, the process of forming a patina using the treatment liquid according to the present invention will be explained in detail using an example in which the chemical conversion treatment liquid is an "aluminum chloride aqueous solution" and the oxidizing agent is manganese dioxide. Even if the chemical conversion treatment solution of the present invention applied to a substrate on which an electrodeposited thin film is formed is other than an aqueous aluminum chloride solution, and even if the oxidizing agent is other than manganese dioxide, substantially the same effects can be obtained under substantially the same conditions. It has been confirmed that it will be played.

There is no particular restriction on the concentration of aluminum chloride, which is the chemical conversion treatment solution of the present invention, but an aqueous solution of 5 to 50% by weight, preferably 20 to 30% by weight is usually used. Similarly,
The amount of manganese dioxide, which is an oxidizing agent, added is not particularly limited, but is usually 3% by weight or more, preferably 5 to 20% by weight. Then, during the treatment, a treatment liquid made by adding manganese dioxide to an aqueous aluminum chloride solution is applied to the "thin film made of copper or copper alloy", or a method such as spraying, or a method such as dipping the thin film in the treatment liquid is used to form a patina. will be held.

When this treatment is carried out, the "electrodeposited thin film made of copper or copper alloy" turns white, albeit instantaneously, and then, as time passes, a patina is produced, which can be seen from the change in the color of the thin film.

Although this "mechanism of patina formation when an electrodeposited thin film made of copper or copper alloy is treated with the treatment solution according to the present invention" has not been clearly elucidated at present, X-ray diffraction has revealed that It has been confirmed that the patina is chemically stable basic cupric chloride (CuC12,3Cu(OH)zl. Therefore, (1) chemical formation reaction, (■) oxidation reaction, (■) patina formation reaction) Dividing the process into three processes, it is assumed that the following reaction is proceeding.

(I) Chemical reaction (a) Aluminum chloride is partially hydrolyzed.

A1C1y+3 HzO=AI(OH)x + 3H
α...(1)(11) The generated hydrochloric acid reacts with copper or copper alloy or the oxide formed on the surface.

2Cu+ 2 HCI = 2Cuc1+ Hz
-(21CuzO+2HCf=2Cu(J+Hz
O=131CuO+ 2 HCf =Cu(Jz +H
zo-(41(iii)) The produced Cu(J) partially causes a disproportionation reaction.

2 Cu (j = CuCfz + Cu
-(51) In reality, various reactions (for example, the reverse reaction of formula (4), etc.) are considered to occur in addition to the reactions of formulas (1) to (5) above.

Note that the reaction expressed by equation (2) does not occur under normal conditions, but in the case of electrodeposited films, the metal structure is weakly bonded (nearly amorphous), so the electrode potential of the film is lower than that in normal conditions. It is thought that this reaction occurs because it is baser than similar materials.

On the other hand, alkali metal chlorides (e.g. KCl, NaCl, etc.) and/or alkaline earth metal chlorides (e.g. Mg(J
In a treatment solution in which aluminum powder is added to (e.g., CaCj'z), for example, the following reaction occurs when the aluminum powder is added.

6Nacl+2AI+6HzO=2A1(J
: ++6NaO1' (+3Hz...-(6) Therefore, it is thought that almost the same reaction occurs after that as in the case of a treatment solution containing aluminum chloride alone (excluding the oxidizing agent). When using a treatment solution of the present invention, manganese dioxide is added after the chemical conversion treatment solution of the present invention is created by adding aluminum powder to an aqueous solution consisting of an alkali metal chloride and/or alkaline earth metal chloride, that is, after the completion of hydrogen generation. It is preferable to do so in consideration of the usage efficiency of manganese dioxide.

In addition, in the case of a treatment solution to which known patina herbal medicines such as alum di-copper sulfate and copper nitrate are added, some of the solution becomes sulfate or nitrate, but the essential reaction is considered to be almost the same. In addition, when alum, copper sulfate, copper nitrate, etc. are added in this way, the effect of subtly changing the tone of the patina that is finally formed can be obtained, but if too large a quantity is added, the rate of formation of patina will be slowed down. Become slow. Therefore, when adding the above-mentioned known patina herbal medicine, the amount added should be adjusted to about 1 to 15% by weight, preferably about 1 to 5% by weight, although there is no particular restriction.

(n) Oxidation reaction (al Oxidized by cuprous chloride or manganese dioxide to become cupric chloride and copper hydroxide.

2CuC7+2Hzo+Mn0z -CuC1z + CI(OH)2 + Mn(OH)
2-(7)2CuC1+ 2 HzO+MnO7 -2Cu(○H)z+MnC/z =181
(bl Copper and/or copper oxide is oxidized by manganese dioxide or becomes copper hydroxide by hydrolysis.

Cu + 2 Hz O+ Mn Oz= 3 Cu(
OH)z + Mn(OH)z −(9)CuZ
O+3 H2O+Mn0z -2Cu(OH)z + Mn(OH)z -0
0) CuO+ H2O=Cu(OH)z
-QυIn addition, manganese dioxide (also lead dioxide, permanganate, etc.) is not directly involved in the above oxidation reaction.
, Cu40. It is also assumed that it acts as a catalyst for the oxidation of CuflJ, etc., and is a very effective additive for the formation of patina.

(I [I) Patina production reaction (al Cupric chloride and copper hydroxide react to produce basic cupric chloride (patina).

Cu(J z + 3 Cu(OH)z = CuCl
2,3Cu(OH)z-(121Of course, these reactions (
L Il, I[[) proceed not independently but in parallel, and eventually form a chemically stable compound, verdigris (
It is thought to become basic cupric chloride).

The substrate on which a patina has been formed by the treatment with the chemical conversion treatment solution of the present invention to which an oxidizing agent has been added (i.e., the "treatment solution according to the present invention") is preferably subjected to curing that also serves as drying. This is not necessary; 2 to 24 hours at room temperature is usually sufficient.

In this way, it is possible to form a uniformly colored patina with extremely good adhesion in a short time.

Next, the present invention will be explained in more detail with reference to Examples.

<Example> Example 1 First, a pre-degreased copper plate (220n + width x 250mm
length x 0.3I thickness), and air pressure 1.5 to 5 kg/cffl (
The surface of the copper plate was roughened by blasting at a pressure of 100 mL (cane pressure).

Next, using the copper plate (roughened surface) as a cathode and the lead plate as an anode, a copper sulfate solution (CuSOa・5H20: 15
0g/L HzSO=: 80g/j was used as the electrolyte, current density: 80A/dm.

Flow rate of plating solution: 1.5 m/see.

Electrolysis was performed for 5 minutes at a liquid temperature of 55° C. to form a new copper thin film by electrodeposition on the surface of the copper plate.

Next, a reaction layer was formed by uniformly applying "a solution containing 5% by weight of manganese dioxide powder in an aqueous solution of 30% by weight of aluminum chloride (i.e., the chemical conversion treatment solution of the present invention)" onto the copper thin film using a brush. Thereafter, curing, which also served as drying, was performed at room temperature for 8 hours.

When the patina formed by the above treatment was observed, it was found that the patina had a deep bluish green tone, and even when the patina film was rubbed with a fingertip, no peeling occurred at all. (It was confirmed that the adhesion was superior to that of natural patina.

Furthermore, analysis by X-ray diffraction confirmed that the patina formed by the method of the present invention is basic cupric chloride (Cu(Jz.3Cu(OH)zl), which is the main component of natural patina.

Example 2 Example 2 except that the surface of the copper plate was roughened by "etching treatment using a known chemical polishing solution" and an aqueous solution of 12% by weight of tin chloride was used as the chemical conversion treatment solution of the present invention. 1
A patina was formed in the same manner as above.

The patina coating thus obtained had a strong blue tone and was uniform with extremely excellent adhesion and no peeling.

Example 3 A saline solution (Na(J?M degree=
A patina was formed in the same manner as in Example 1, except that 5% by weight of aluminum powder was added to 5% by weight).

The resulting patina film was uniform, had a color tone almost the same as natural patina, and had extremely excellent adhesion.

Example 4 In this example, alum (KAf3 (S
A patina was formed in the same manner as in Example 1, except that 5% by weight of 0a)z(OH)6) crystals was added.

The resulting patina film was uniform and had good adhesion with no peeling material.

In addition to these examples, various electrodeposition conditions were used to form copper or copper alloy thin films, and the type of oxidizing agent was also varied.
Tests were conducted using various combinations of these methods, and it was confirmed that in all cases, if the method of the present invention was followed, good results could be obtained that were almost the same as in the above examples.

Summary of Effects> As explained above, according to the present invention, it is possible to stably form patina on all kinds of substrates in a short time, exhibiting a deep color tone almost the same as natural patina, and having extremely excellent adhesion. Moreover, since it does not require any special equipment, it can be installed on-site, and can be easily applied to, for example, repairing patina products. Therefore, it is expected to be applied not only to roofing materials but also to a wide range of fields such as building interior wall materials and decorative items, resulting in extremely useful effects industrially.

Claims (4)

[Claims] (1) After electrodepositing a thin film of copper or copper alloy on the surface of the substrate on which patina is to be formed, (a) applying aluminum powder to an alkali metal chloride and/or alkaline earth metal chloride; (b) aluminum chloride, (c) tin chloride, (d) zinc chloride, and (e) lead chloride. A method of forming a patina characterized by processing. (2) Electrodeposition of thin films made of copper or copper alloys at current density:
The method for forming a patina according to claim 1, which is carried out while controlling the flow rate of the plating solution to be 75 A/dm^2 or more and a flow rate of the plating solution to be 1 m/sec or more. (3) The oxidizing agent to be added contains (a) manganese dioxide, (b) lead dioxide, (c) permanganate, (d) chromate and/or dichromate, (e) free iodine. Claim 1 or 2 is one or more selected from iodine compounds that
The patina formation method described in . (4) The method for forming a patina according to any one of claims 1 to 3, wherein the surface of the base material on which the patina is to be formed is roughened, and then a thin film made of copper or a copper alloy is formed by electrodeposition.