JPH11189881A - Blackening treated composition and blackening treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regulate the compsn. of a composition subjecting the surface of brass to blackening treatment to the one free from deterioration and whose maintenance is made possible. SOLUTION: The composition has a compsn. contg. (A) at least one kind selected from basic copper carbonate, copper hydroxide, copper oxide (II) and tetraamminecopper (II) salt shown by the formula of [Cu(NH3 )4 ]X2 (X denotes a monovalent anion composed of OH, Cl, NO3 , NCS, Cu (I) Cl2 , 1/2SO4 , HCO3 and 1/2CO3 ), (B) at least one kind selected from aq. ammonia, gaseous ammonia, liq. ammonia, ammonium carbonate and ammonium hydrogencarbonate and (C) water as the residue, and the concn. of (the copper components, the ammonia components) in the composition lies within the range surrounded by each point of (0.2 wt.%, 2 wt.%), (0.2 wt.%, 10 wt.%), (1.5 wt.%, 20 wt.%), (2.5 wt.%, 20 wt.%), (2.5 wt.%, 10 wt.%) and (1.5 wt.%, 2 wt.%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black processing composition used for black processing the surface of an object to be processed such as copper such as brass, and a black processing method for performing black processing using the black processing composition. About.

[0002]

2. Description of the Related Art Brass is easily used in machining such as cutting and pressing, has appropriate hardness, and is inexpensive. Therefore, brass is widely used in precision machine parts requiring dimensional accuracy. In order to eliminate the reflection of light from the surface of the component without changing the dimensions of the brass component, copper carbonate can be painted with Japanese black ink or immersed in a treatment bath consisting of basic copper carbonate and concentrated ammonia water to be treated with black. The law has been practiced for a long time (Robo Boshin, Introduction to New Edition Metal Surface Processing, Jinjinshokan, P159-160 (1
976)). In this case, the dimension increase in the painting with Japanese black ink is as small as 1 μm or less, and the dimension hardly changes by the treatment by the copper carbonate method. In particular, the copper carbonate method is widely used because basic copper carbonate added when a treatment bath is constructed or supplied is quickly dissolved in aqueous ammonia and can be prepared and supplied in a short time.

[0003]

However, since painting with Japanese black ink has low adhesion, there is a problem that when it is used for a fitting portion or a sliding portion of a component, it becomes a fine coating film piece and peels off. In addition, since the painting operation requires a lot of labor, there is a problem that the cost is high.

[0004] On the other hand, in the copper carbonate method, a plurality of objects to be treated are put together in a basket or the like, degreased and acid-activated by a conventional method, and then simply immersed in a treatment bath. There is an advantage that processing can be performed manually. However, since the ammonia concentration in the bath is high, the volatilization of ammonia is large, so it is difficult to maintain a constant composition,
In addition, the capacity of the exhaust system needs to be increased.

Since concentrated ammonia water is inexpensive and easy to handle, it is used to recover the ammonia concentration in the bath. However, 73% by weight of concentrated ammonia water is water. There is also a problem that unnecessary water is brought into the bath, the amount of liquid increases, and a part of the water must be discarded. On the other hand, the copper component in the bath does not volatilize, but the concentration gradually decreases due to the carry-in of the washing water in the pre-treatment step, the consumption of the treatment itself, and the removal to the next step, etc. It is necessary to replenish as well. This replenishment uses a basic copper carbonate having water in the molecule to restore the copper concentration in the bath, so it is less than the replenishment of concentrated ammonia water, but also unnecessary water enters the bath. There's a problem.

The present invention has been made in view of such conventional problems, and has as its object to provide a novel composition and a processing method effective for blackening the surface of brass. .

[0007]

In order to achieve the above object, the black processing composition according to the first aspect of the present invention is a composition effective for black processing of brass, comprising (A) a basic copper carbonate and water. At least one selected from copper oxide, copper (II) oxide or a tetraammine copper (II) salt represented by the formula 2, and [Cu (NH ₃ ) ₄ ] X ₂ (where X is OH, Cl, NO ₃ , NCS, monovalent anion composed of Cu (I) Cl ₂ , 1 / 2SO ₄ , HCO ₃ , 1 / 2CO ₃ ) Formula 2 (B) ammonia water, ammonia gas, liquid ammonia, ammonium carbonate, hydrogen carbonate And at least one selected from ammonium and (C) water as a residue, wherein the concentration of (copper component, ammonia component) in the composition is (0.2% by weight, 2% by weight), 0.2% by weight, 10
Wt%), (1.5 wt%, 20 wt%), (2.5 wt%, 20 wt%), (2.5 wt%, 10 wt%),
(1.5% by weight, 2% by weight).

[0008] The concentration of (copper component, ammonia component) in the above black processing composition is (0.2 wt%, 2 wt%), (0.2 wt%, 10 wt%), (1.5 wt%). %, 20% by weight), (2.5% by weight, 20% by weight),
(2.5% by weight, 10% by weight), (1.5% by weight, 2% by weight), black processing is possible when it is within the range surrounded by each point. %, 3% by weight),
(0.5 wt%, 5 wt%), (1.5 wt%, 15 wt%), (2 wt%, 15 wt%), (2 wt%, 10 wt%
(% By weight) and (1% by weight, 3% by weight), the temperature and the time of the black treatment can have a certain range, and more preferably (0.5% by weight). , 3% by weight), (0.5% by weight, 5% by weight), (1% by weight, 10% by weight)
(% By weight), (1.7% by weight, 10% by weight), (1.7% by weight, 8% by weight), (1% by weight, 3% by weight) black treatment Temperature and the time range thereof can be further widened, most preferably (1% by weight,
(5% by weight), the temperature of the black treatment and the range of the time can be maximized.

Within the above-mentioned range, it is necessary that part or all of (A) be dissolved in (B) and (C). Furthermore, in order to black-treat the surface of brass, it is necessary to dissolve it in the form of tetraammine copper (II) ions.

Various tetraammine copper (II) in (A)
Salt (tetraammine copper hydroxide, tetraammine copper chloride,
Copper tetraammine nitrate, copper tetraammine isothiocyanate, copper chloride (I) copper tetraammine, copper copper tetraammine, copper copper tetraammine, copper copper tetraammine) are (B) and (C) tetraamine copper (II) ions and various pairs. Dissolves by ionizing ions. On the other hand, the basic copper carbonate, copper hydroxide, copper oxide (I
I) dissolves in the form of tetraammine copper (II) ions by complexing with (B) ammonia water, ammonia gas, liquid ammonia, ammonium carbonate, and ammonium bicarbonate. In summary, when the compound (A) containing copper or ammonia is dissolved in an aqueous solution of the compound containing ammonia or the simple substance (B), all the compounds are in the same tetraammine copper (II) ion form. When used, there are the following advantages as compared with the conventional copper carbonate method.

First, since commercially available copper hydroxide has less impurities than basic copper carbonate, the use of the same makes it possible to prepare a black processing composition with less deterioration.

Second, since copper (II) oxide contains more copper than basic copper carbonate and is inexpensive, a black processing composition can be prepared at low cost by using it.

Third, when a copper component is replenished to a black processing composition thinned by use, water is generated by reaction with ammonia in basic copper carbonate, whereas water is generated in copper (II) oxide. Since copper (II) oxide is not generated, it can be supplied without generating unnecessary water. For this reason, unnecessary increase in the amount of the black treatment composition is suppressed.

Fourth, since the tetraammine copper (II) salt of the formula (2) has copper and ammonia in the molecule, the copper component and the ammonia component can be simultaneously prepared and replenished by using this. Further, there is an advantage that unnecessary water is less generated than when the copper component and the ammonia component are separately supplied.

Fifth, (B) needs to contain ammonia in order to react with (A). The aqueous ammonia, ammonia gas, and liquid ammonia in (B) react with the basic copper carbonate, copper hydroxide, and copper (II) oxide in (A) as they are. On the other hand, ammonium carbonate and ammonium hydrogen carbonate decompose into ammonia, carbon dioxide, and water to react. At this time, since the ammonium carbonate or ammonium hydrogen carbonate remaining in the black treatment composition forms a salt, it is less likely to volatilize as compared with free ammonia. Therefore, the composition can be easily maintained, and the load on the exhaust equipment can be reduced.

Sixth, (B) contains 73% by weight of concentrated ammonia water, 0% by weight of both ammonia gas and liquid ammonia, and 1% by weight of ammonium carbonate.
1.4% by weight, 22.8% by weight of ammonium bicarbonate
It is. Thus, when an ammonia component is supplied to a black processing composition whose concentration has been reduced by use, use of ammonia gas and liquid ammonia has an advantage that unnecessary water is not brought in. Following this are ammonium carbonate and ammonium bicarbonate, which carry less water. Replenishment with concentrated ammonia water is not appropriate because unnecessary water is often brought in.

Next, a specific method for preparing and replenishing the black processing composition will be described. The amounts of (A), (B) and (C) required to prepare the black treatment composition are determined by specific examples. For example, tetraammine copper hydroxide as (A),
Using ammonium bicarbonate as (B), a black processing composition having a concentration of the copper component of (A) and the ammonia component of (A) or (B) of (0.2% by weight, 2% by weight) was obtained.
When preparing kg, the copper tetraammine hydroxide contains 38.3% by weight of a copper component, so that 5.2 g (= (0.2% by weight)
/100)/(38.3% by weight / 100) × 1000
g) Required.

41.1% by weight of copper tetraammine hydroxide
Since it is an ammonia component, it contains 2.1 g of ammonia in 5.2 g. Since the required amount of ammonia is 20 g, the remaining 17.9 g is supplemented with ammonium carbonate. Since ammonium carbonate contains 32.5% by weight of an ammonia component, 55.1 g (= 17.9 g / (32.5% by weight / 100)) is required. The remaining water (C) is 93
0.7 g (= 1000 g-5.2 g-55.1 g), in which 5.2 g of copper tetraammine hydroxide and 55.1 g of ammonium carbonate are dissolved.

Next, how to determine the amounts of (A) and (B) necessary for replenishment of the black processing composition will be described. The amounts of (A) and (B) required for replenishment are obtained as solutions to the simultaneous equations. Table 1 shows a list of constants and variables appearing in the equations.

[0020]

[Table 1]

The black processing composition, which becomes thinner by use and cannot be subjected to black processing without replenishment, that is, the weight percentage of the copper component of the black processing composition before replenishment is a ₀ , the weight percentage of the ammonia component is b ₀ , water, etc. of the weight percent of component and c _0.
The sum of a ₀ , b ₀ , and c ₀ amounts to 100% by weight. a ₀ + b ₀ + c ₀ = 100 Equation 3

The relationship of the formula (3) also holds for (A), (B) and the replenished black treatment composition. Note that there is no a _{B in} Equation 5 because (B) does not contain a copper component. a _A + b _A + c _A = 100 Equation 4 b _B + c _B = 100 Equation 5 a ₁ + b ₁ + c ₁ = 100 Equation 6

The weight W ₀ of the black processing composition before replenishment is
(A) a W _A, the addition of W _B to (B), the weight W ₁ of the black processing composition after supplementation is required. _{W 1 = W 0 + W A} + W B ... Formula 7

The weight of copper contained in the black processing composition W ₀ before replenishment is (a ₀ W ₀ ) / 100, and the weight of copper contained in (A) is (a _A W _A ) / 100. The weight of copper contained in the black processing composition after replenishment is (a ₁ W ₁ ) / 100. A relationship similar to Equation 7 holds between the three copper weights. _{a 1 W 1 = a 0 W} 0 + a A W A ... Formula 8

The relationship of Equation 8 also holds for the weight of ammonia, water and other weights. _{b 1 W 1 = b 0 W} 0 + b A W A + b B W B ... Equation _{9 c 1 W 1 = c 0} W 0 + c A W A + c B W B ... Equation 10

When the concentrations of all the components are all obtained from the equations 3, 4, 5, and 6, and substituted into the equations 7, 8, 9, and 10, the replenishment amount W _{A in} (A) and the replenishment amount in (B) are obtained. W _B is required.

The above-mentioned preparation method can also be carried out by solving the formulas 3 to 10 using the black processing composition before replenishment as water.
Necessary amount W _A of (A), a W _B necessary amount of (B), (C)
Can be obtained in the same way as W ₀ .

A specific example of the replenishment method will be described. The replenishment method is basically the same as the preparation method described above, except for the difference between dissolving in water or dissolving in the black processing composition thinned by use. 1 kg of the black processing composition having a copper component concentration of 0.2% by weight and an ammonia component concentration of 2% by weight contains 2 g of a copper component, 20 g of an ammonia component, and 97 parts of water and the like.
8g.

When the concentration of the copper component is adjusted to 1% by weight and the concentration of the ammonia component is adjusted to 5% by weight, a combination of copper (II) oxide and ammonium carbonate is added to each of them.
While 1.5 g and 111.2 g are required, 18.0 g and 140.5 g, respectively, are required for the combination of basic copper carbonate and concentrated ammonia water which are the conventional copper carbonate method. These replenishment amounts are obtained by solving Equations 3 to 10. Comparing the two combinations, the former combination has the advantage that unnecessary water is less generated or brought in, so that the amount of unnecessary liquid is increased by 35.8 g and the amount of waste is reduced.

An object to be treated consisting of brass is used as the black treatment composition of the present invention, for example, a composition in which the concentration of the copper component (A) and the concentration of the ammonia component (B) are (1% by weight, 5% by weight). Upon contact, zinc, which is a component of brass, is oxidized on the surface by tetraammine copper (II) ions near the surface and dissolved as a tetraammine zinc complex, and at the same time, tetraammine copper (II) ions are converted to diammine copper (I ) Reduced to ions (reaction 1).

Copper, which is the other component of brass on the surface of the object to be treated, is also oxidized by tetraammine copper (II) ions to dissolve as diammine copper (I) ions, but the reaction rate is higher than that of zinc. Slow (reaction 2).

The diammine copper (I) ion is oxidized by dissolved oxygen to become tetraammine copper (II) ion and copper (II) oxide (reaction 3).

The produced copper (II) oxide is black, and it is blackened by adhering to the surface of the object to be treated or entering the pores of the atomic level from which zinc has been desorbed.

Since tetraammine copper (II) ion, ammonia and copper (II) oxide are in an equilibrium relation, when there is sufficient tetraammine copper (II) ion with respect to ammonia as in the black treatment composition of the present invention. The copper (II) oxide on the surface of the object is not dissolved by ammonia. When the reaction proceeds and the surface of the object to be treated is covered with copper oxide (II), the above-described reactions 1 to 3 stop. This has the advantage that the surface is not roughened even if the object is in contact with the black processing composition for an unnecessarily long time.

In the comparative composition 1 in which the concentrations of the copper component (A) and the ammonia component (B) are not (0.1% by weight, 1% by weight), which are not the compositions of the black processing composition of the present invention, Since the concentrations of the copper component (A) and the ammonia component (B) in the composition 1 are both low and the reactions 1 to 3 proceed only slightly, the surface of the processing target 1 has a slightly black brass color. Therefore, it is not suitable for use.

In the comparative composition 2 in which the concentrations of the copper component (A) and the ammonia component (B) are not (0.2% by weight and 20% by weight), which are not the black processing composition of the present invention,
The concentration of the ammonia component of (B) in Comparative Composition 2 was 20
Although the amount is necessary and sufficient, the amount of the copper component (A), that is, tetraammine copper (II) ion, is small, so that the reactions 1 and 2 are slowed down, and the generation of diammine copper (I) ion is small. For this reason, ammonia is present in excess around the diammine copper (I) ion, and even if the diammine copper (I) ion is oxidized by dissolved oxygen, almost no copper (II) oxide is generated, and almost all It becomes tetraammine copper (II) ion (reaction 4). Therefore, the surface of the object is not covered with copper (II) oxide. In the comparative composition 2, the dissolution of the surface of the processing target 1 proceeds by these reactions 1, 2, and 4, and the surface becomes rough. In this case, since the zinc component is dissolved in particular, the copper component is increased and the color becomes reddish brown, so that it is not suitable for use.

Furthermore, in the comparative composition 3 in which the concentrations of the copper component (A) and the ammonia component (B) are not (3% by weight and 25% by weight), which are not the other black processing compositions of the present invention,
The concentrations of the copper component (A) and the ammonia component (B) in the comparative composition 3 are both high. Even when the ammonia component of (B) is increased, the dissolution of the copper component of (A), that is, the tetraammine copper (II) ion reaches the limit, so that the concentration of the tetraammine copper (II) ion dissolved in the comparative composition 3 is increased. Ammonia concentration with respect to. Therefore, reaction 3
And reaction 4 proceed simultaneously, and the surface of the object to be treated is copper oxide (I
It is not suitable for use, since it becomes copper-brown with I) and becomes blackish brown.

Further, in Comparative Composition 4, which is not the black processing composition of the present invention, for example, the concentration of the copper component (A) and the ammonia component (B) is (3% by weight, 2% by weight) Although the concentration of the copper component (A) in Comparative Composition 4, that is, the tetraammine copper (II) ion, is excessive at 3% by weight,
Can be processed black. However, the proportion of tetraammine copper (II) ions that do not contribute to the reaction without dissolving is large, which is not only useless because it is not only wasteful but also makes cleaning after treatment difficult.

As described above, according to the first aspect of the present invention, it is possible to obtain a novel composition effective for blackening the surface of the object to be treated made of brass.

According to a second aspect of the present invention, there is provided the black processing method, wherein the whole or a part of the surface of the object made of brass is treated with 10 to 40 parts.
It is characterized by being brought into contact with the above-mentioned black treatment composition adjusted to a temperature of ° C.

Here, the contact between the object to be treated and the black treatment composition of the present invention is not limited to immersion, but may be applied, such as coating, spraying, showering, etc.
Other known methods can be used.

The temperature of the black processing composition of the present invention when immersing the object to be treated is in the range of 10 to 40 ° C., preferably in the range of 15 to 30 ° C., more preferably 20 to 30 ° C.
It is in the range of ３０30 ° C. The immersion time is 0.2 to 20
Minutes, preferably in the range of 0.5 to 15 minutes, more preferably in the range of 1 to 10 minutes. When the temperature of the black processing composition of the present invention at the time of immersing the object to be treated is out of the range of 10 to 40 ° C., that is, when the temperature is less than 10 ° C., the reaction becomes slow. If it exceeds, the amount of ammonia volatilized increases, so that it is not suitable for use. Also, the immersion time is out of the range of 0.2 to 20 minutes,
That is, since the reaction is not completed in less than 0.2 minutes, the surface of the object to be treated is not blackened, and if the time exceeds 20 minutes, the reaction is completed, and there is no point in further immersion.

According to the second aspect of the present invention, it is possible to provide an effective processing method for blackening the surface of the workpiece made of brass.

According to a third aspect of the present invention, there is provided the second aspect of the present invention, wherein the workpiece is intermittently wetted with the black processing composition while the object to be processed is brought into contact with the black processing composition according to the first aspect. In a state of being brought into contact with a gas containing oxygen.

The contact between the object to be treated and the gas containing oxygen is not limited to completely lifting the object to be treated into the gas, but also to bringing out only a part of the object to be treated into the gas or to the black treatment composition. Other known methods can be used, such as touching bubbles made of gas while immersed. When the contact of the black processing composition is performed by application, spraying, or showering, the supply of the black processing composition is temporarily stopped to make contact with the gas.

"Intermittently" means that gas contact is made at least once between the start and the end of the process.

The time for bringing the object into contact with the gas is preferably in the range of 3 to 60 seconds, more preferably in the range of 5 to 40 seconds, and most preferably in the range of 20 to 30 seconds.
Within seconds. If the time of contacting the object to be treated with the gas is out of the range of 3 to 60 seconds per time, that is, less than 3 seconds, the progress of the reaction is insufficient, so that the time required for the black treatment cannot be shortened. If the time exceeds 60 seconds, a part of the surface of the object to be treated is dried, resulting in an uneven treatment, which is not appropriate.

The black treatment method of the present invention proceeds by the reaction of diammine copper formed in the black treatment composition near the surface of the object to be treated with dissolved oxygen to form copper (II) oxide. If the supply of oxygen is not sufficient, the concentration of dissolved oxygen near the surface of the object to be treated decreases, and the reaction slows down.

When the object to be treated is pulled up into air, oxygen or a mixture of oxygen and air, the surface of the object is covered with a thin wet film of the black treatment composition. Since the black processing composition in the film state has a large surface area with respect to the volume, it quickly absorbs oxygen in the gas. As a result, oxygen sufficient for the reaction is always supplied, and the blackening process proceeds rapidly.

The composition of such a wet film changes in units of seconds due to the dissolution of zinc from the object to be treated, the consumption of a copper component, the volatilization of an ammonia component and water, and the like. By performing the process intermittently, processing with high blackness can be performed in a shorter time.

According to the third aspect of the present invention, it is possible to provide an effective processing method for blackening the surface of the object made of brass in a short time.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiments 1-6) Embodiments 1-6 vary the components of the black processing composition. C3604 brass rods with diameter (φ)
A part cut into a spherical shape of 20 mm was used. The black treatment composition was prepared by combining and mixing a compound (A) containing copper or ammonia and a compound or a simple substance (B) containing ammonia, and adding water so that the composition becomes as shown in Table 2. (A) as basic copper carbonate, copper hydroxide,
Copper (II) oxide, various tetraammine copper (II) ions (tetraammine copper hydroxide, tetraammine copper chloride, tetraammine copper nitrate, tetraammine copper isothiocyanate,
Any one of copper chloride (I) tetraammine copper, tetraammine copper sulfate, tetrahydrogencarbonate copper, and tetraamminecarbonate copper) was selected and used. Similarly, any of ammonia water, ammonia gas, liquid ammonia, ammonium carbonate, and ammonium hydrogen carbonate was selected and used as the compound containing ammonia or the simple substance (B). The preparation of the black treatment composition comprises (A)
There are 55 combinations depending on the combination selected by (B).

[0053]

[Table 2]

In the first embodiment, 1 kg of a black processing composition containing 0.2% by weight of a copper component and 2% by weight of an ammonia component was prepared by combining copper (II) oxide and ammonium carbonate. In this case, copper (II) oxide contains 79.9% by weight of copper, and ammonium carbonate contains 32.5% by weight of ammonia. Therefore, 2.5 g and 61.5 g of each were used. To this, 936 g of water is added, and the mixture is placed in a SUS container with a lid and stirred for about half a day. When 20 g of ammonia gas is used instead, ammonia gas having a specific gravity of 2.8 l
It can be adjusted by absorption in 77.5 g of water.

Copper (II) oxide is harder to dissolve than basic copper carbonate, so that it takes a long time to stir. However, when other compounds containing copper or ammonia (A) are used, the stirring takes about 30 minutes. Good. Similarly, in the first embodiment (A),
Black treatment compositions were also prepared in other combinations depending on the selection of (B). Embodiments 1 to 2 are also applied to Embodiments 2 to 6.
The same was done.

When (A) is dissolved in the aqueous solution of (B),
(A) may be a mixture since all of them become the same tetraammine copper (II) ion. At this time, since (B) is also decomposed to release all the same ammonia, (B) may be a mixture.

As Comparative Examples 1, 2, 3, and 4,
Comparative compositions in which the concentration of the copper component of (A) or the ammonia component of (B) was outside the scope of the claims were prepared at the concentrations shown in Table 2.

After the above-mentioned brass parts were degreased and acid-activated by a conventional method, they were immersed in a black processing composition at 25 ° C. for 10 minutes to perform black processing. Next, the brass part was washed with water and dried in an oven at 70 ° C. for 30 minutes. The contact between the brass component and the black processing composition is not limited to immersion, and other known methods such as coating, spraying, and showering may be used.

In Comparative Examples 1-4, brass parts were immersed in a comparative composition at 25 ° C. for 10 minutes. Other steps are the same as those in the first to sixth embodiments.

Table 2 shows the results. After black processing, those that can be judged to be sufficiently black by visual observation are marked with “○”, and those that are not, marked with “x”. Table 2 shows that when both the copper component of (A) and the ammonia component of (B) have the concentrations shown in the claims, they are effective for black processing.

When the brass part comes into contact with the black processing composition of the first to sixth embodiments, zinc, which is a component of brass, is oxidized on the surface thereof by tetraammine copper (II) ions near the surface to form a tetraammine zinc complex. To dissolve, and at the same time, tetraammine copper (II) ions are reduced to diammine copper (I) ions (reaction 1).

Copper, the other component on the surface of the brass part, is also oxidized by tetraammine copper (II) ions and dissolved as diammine copper (I) ions, but the reaction rate is slower than zinc (reaction). 2). The diammine copper (I) ion is oxidized by dissolved oxygen to become tetraammine copper (II) ion and copper (II) oxide (reaction 3).

The produced copper (II) oxide is black, and the copper oxide is blackened by adhering to the surface of the brass part or entering the holes of the atomic level from which zinc has been eliminated. Since tetraammine copper (II) ion, ammonia and copper oxide (II) are in an equilibrium relation, when the tetraammine copper (II) ion is sufficiently present with respect to ammonia as in Embodiments 1 to 6, the surface of the brass component Copper (II) oxide is not dissolved by ammonia. Therefore, when the surface of the brass component is covered with copper (II) oxide, reactions 1 to 3 stop. As a result, even if the brass part has been in contact with the black processing composition for an unnecessarily long time, its surface will not be roughened.

In Comparative Example 1, the concentrations of the copper component (A) and the ammonia component (B) in the comparative composition were both low, and reactions 1 to 3 proceeded only slightly. Color.

In Comparative Example 2, the concentration of the ammonia component (B) in the comparative composition was 20% by weight, which was necessary and sufficient.
Since the copper component of (A) is small, ammonia is relatively excessive. Therefore, copper (II) oxide is hardly generated, and the surface of brass parts is not covered with copper (II) oxide.
Dissolution proceeds and the surface becomes rough. At this time, in particular, since the zinc component is dissolved, the copper component is relatively increased, and a reddish brown color is exhibited.

In Comparative Example 3, the concentrations of the copper component (A) and the ammonia component (B) in the comparative composition were both high. In such a case, the dissolution of the copper component (A), that is, the tetraammine copper (II) ion, reaches the limit, so that ammonia becomes relatively excessive as in Comparative Example 2. For this reason, the formation of copper (II) oxide on the surface of the brass component is small, and the brass component has a black-brown color.

In Comparative Example 4, although the concentration of the copper component (A) in the comparative composition, that is, the tetraammine copper (II) ion, is excessive at 3% by weight, it can be processed black. However, the proportion of tetraammine copper (II) ions that do not dissolve and do not contribute to the reaction is large, which not only wastes but also makes cleaning after the treatment difficult.

As apparent from Table 2, according to the present embodiment, (A) basic copper carbonate, copper hydroxide, copper oxide (II)
Or at least one selected from tetraammine copper (II) salts represented by the formula 11, and [Cu (NH ₃ ) ₄ ] X ₂ (where X is OH, Cl, NO ₃ , NCS, Cu (I) Cl _{2, 1 / 2SO 4, HCO} 3, 1 / 2CO consisting of _three monovalent anion) equation 11 (B) at least one aqueous ammonia, ammonia gas, liquid ammonia, ammonium carbonate, is selected from ammonium hydrogen carbonate And (C) water as a residue, wherein the concentration of (copper component, ammonia component) in the composition is (0.2% by weight, 2% by weight), (0.2% by weight, 10% by weight) ), (1.5 wt%, 20 wt%), (2.5 wt%, 20 wt%), (2.5 wt%, 10 wt%),
(1.5% by weight, 2% by weight) By using the black processing composition within the range surrounded by each point, the surface of the object to be processed made of brass can be black-processed.

Further, since commercially available copper hydroxide has less impurities than basic carbonic acid, it can be used to prepare a black processing composition with little deterioration. Also, copper (II) oxide
Has no water in the molecule, so using this will not bring unnecessary water and prepare a black processing composition.
Can be replenished.

Further, tetraammine copper (II) of the formula 11
Since the salt has copper and ammonia in the molecule, the copper component and the ammonia component can be simultaneously prepared and replenished by using the salt.

Further, since the ammonia gas and liquid ammonia do not contain water, by using this, the black processing composition can be prepared and supplied without bringing in unnecessary water. Further, since ammonium carbonate and ammonium hydrogen carbonate have a low water content, including water generated when decomposed, as compared with concentrated ammonia water, the use of this reduces the amount of water brought in and reduces blackness. Preparation and replenishment of treatment compositions. Furthermore, the ammonium carbonate or ammonium bicarbonate remaining in the black treatment composition forms a salt and is less likely to volatilize than free ammonia, so that the composition can be easily maintained and the load on the exhaust equipment is reduced. Can be reduced.

(Embodiments 7-12) Embodiments 7-1
No. 2 is obtained by changing the components of the black processing composition, the processing temperature and the time, and only different points from Embodiments 1 to 6 will be described.

The black processing composition is a compound containing copper (A)
And a compound containing ammonia or a simple substance (B) were combined and mixed, and water was added so that the composition became as shown in Table 3, and the mixture was prepared.

[0074]

[Table 3]

As shown in Table 3, the concentration ranges of the copper component (A) and the ammonia component (B) in the seventh to twelfth embodiments are narrower than those in the first to sixth embodiments. A more preferable concentration was used.

In these embodiments, when the brass parts used in the first to sixth embodiments are black-treated with the black treatment composition, the concentration of the black treatment composition and the immersion time are changed.
Four different black treatments were applied. The temperature and the immersion time of the black treatment composition under the conditions 1 to 4 in Table 3 are as follows.
1 minute, condition 2 at 20 ° C, 10 minutes, condition 3 at 30 ° C, 1
Min, condition 4 is 30 ° C. for 10 minutes.

In the evaluations in Table 3, evaluations were made in the same manner as in the first to sixth embodiments, and those that could be judged to be sufficiently black were marked with “○”, and those that were not so marked with “×”. As is clear from Table 3, when both the copper component of (A) and the ammonia component of (B) have the concentrations shown in the claims, the black component is effective. Since all of the conditions 1 to 4 in Embodiments 7 to 12 were blackened, the copper component of (A) and the ammonia component of (B) were (0.5% by weight, 3% by weight), (0. 5
Wt%, 5 wt%), (1 wt%, 10 wt%),
(1.7% by weight, 10% by weight), (1.7% by weight, 8% by weight), (1% by weight, 3% by weight), when the density is within the range surrounded by each point, black treatment The temperature of the composition is between 20 and 30
In the range of ° C., the immersion time is in the range of 1 to 10 minutes, indicating that blackening can be performed.

As is clear from Embodiments 7 to 12,
By narrowing the range of the concentration of the copper component of (A) and the concentration of the ammonia component of (B), the processing temperature and time can be varied, so that even if these processing conditions fluctuate due to some disturbance. , And can maintain stable black processing.

(Embodiments 13 to 16) Embodiment 13
In Nos. To 16, the processing temperature and processing time for the black processing composition were changed, and these conditions are described in Table 4. The black treatment composition was prepared by adding water so that the copper component of (A) and the ammonia component of (B) became 1% by weight and 5% by weight, respectively. Each concentration is the most preferred.

[0080]

[Table 4]

In the thirteenth to sixteenth embodiments, the temperature of the black processing composition 4, which is the condition of the black processing, is set wider than that of the seventh to twelfth embodiments, and is set to 10 to 40 ° C. corresponding to the claims. On the other hand, in Comparative Examples 5 to 10, the treatment was performed at a temperature and an immersion time outside the scope of the claims. Table 3 shows these conditions and results.

In all of the thirteenth to sixteenth embodiments, black processing can be performed in all cases, indicating that black processing can be performed in a temperature range within the scope of the claims. Among them, the embodiment 13 has a processing temperature at the lower limit of the claims and a short immersion time, so that even if the composition of the black processing composition is slightly changed by use, the processing cannot be performed. Processing is difficult.

In Comparative Examples 5 and 6, since the temperature of the black treatment composition was as low as 5 ° C., the reaction was slow, so that the surface of the brass part did not become black and remained unchanged in brass color or was slightly black brass. Color.

In Comparative Examples 7 and 8, since the reaction was not completed because the immersion time was as short as 0.1 minute, the surface of the brass component did not become black, but became slightly black brass or brown.

In Comparative Examples 9 and 10, the temperature of the black processing composition was as high as 45 ° C., and black processing was possible. However, at this temperature, since the ammonia component (B) volatilizes quickly, the composition tends to change, and the capacity of the exhaust equipment needs to be increased. Therefore, to maintain the composition constant, the component (B)
Need to be replenished frequently, which has the problem of increasing costs.

As is clear from the above thirteenth to sixteenth embodiments, by optimizing the concentrations of the copper component (A) and the ammonia component (B), the range of the processing temperature and time can be widened. It is possible to increase the processing amount of the processing target per unit time. Further, since the black processing composition can be used in a normal temperature environment, and heating or cooling is not required, the processing equipment and the air conditioning equipment can be simplified and the operating cost can be reduced.

(Embodiments 17 to 20) Embodiment 17
In No. to No. 20, the copper component is intermittently brought into contact with a gas containing oxygen in the state of being intermittently wetted with the black processing composition during the black processing. Table 5 shows the conditions. The black processing composition used was prepared so that the copper component and the ammonia component were 0.2% by weight and 2% by weight, respectively, and the processing temperature was 2%.
5 ° C.

[0088]

[Table 5]

In the seventeenth embodiment, the brass part was immersed in the black treatment composition for 10 seconds, and was lifted up to 6% in air.
Touching for 0 seconds was repeated until the surface of the brass component could be judged to be sufficiently black.

In the eighteenth embodiment, the time of contact with air by one pulling in the seventeenth embodiment is changed to 10 seconds.

In the nineteenth embodiment, the shower of the black processing composition was allowed to flow over the brass parts for 10 seconds, and the shower was stopped and exposed to air for 10 seconds.

In the twentieth embodiment, the air in the seventeenth embodiment is changed to an oxygen atmosphere.

In Comparative Example 11, only continuous immersion was performed. In Comparative Example 12, the shower was kept flowing. Comparative Example 13
In the embodiment, the time of contact with air by one pulling of the seventeenth embodiment is changed to 90 seconds.

In the seventeenth embodiment, the processing time required for blackening was reduced from 10 minutes in Comparative Example 11 to 6 minutes by repeatedly performing air contact with the brass parts for 60 seconds. When the brass part is lifted into the air, the surface of the brass part is covered with a thin wet film of the black treatment composition. Since the black processing composition in the film state has a large surface area with respect to the volume, it quickly absorbs oxygen in the gas. Thereby, oxygen sufficient for the reaction is always supplied, and the blackening process proceeds rapidly.

The eighteenth embodiment is different from the seventeenth embodiment in that
By shortening the time of contact with air by 10 times and increasing the number of times, the processing time required for blackening can be reduced to 5 minutes, which is shorter than that of the seventeenth embodiment. The composition of the wet film changes in units of seconds due to dissolution of zinc from brass components, consumption of copper components, evaporation of ammonia components and moisture, etc., so that one pull-up time is shortened and repeated intermittently. This is because processing with high blackness can be performed in a shorter time.

In the nineteenth embodiment, by changing to a shower, the processing time required for blackening can be reduced to 4 minutes, which is shorter than in the seventeenth embodiment. This is because, in the black treatment, when the treatment proceeds due to the formation of copper oxide (II) by the reaction of dissolved oxygen with the diammine copper formed in the black treatment composition near the surface of the non-treated material, the shower is more immersed than immersed. Is that the concentration of dissolved oxygen in the black processing composition near the surface does not easily decrease because the black processing composition is quickly replaced. In addition, this time is shorter than 8 minutes in Comparative Example 12 in which the shower was continuously applied.

In the twentieth embodiment, the processing time required for blackening is increased by increasing the oxygen concentration in the seventeenth embodiment.
It was shortened to 3 minutes, which is even shorter.

In Comparative Example 11, only the immersion was performed, and the supply of oxygen was not sufficient. Therefore, the concentration of dissolved oxygen near the surface of the object to be treated was lowered, and thus the treatment required a long time.

In Comparative Example 13, since the time of contact with air by one pull was extended to 90 seconds, the treatment was uneven brown to black, and could not be uniformly blacked even after 2 hours. This is because a part of the surface of the brass part dries during pulling and changes its state. For this reason, it is preferable that the time of contact with air in one pulling is 60 seconds or less.

The contact between the brass part and the gas containing oxygen is not limited to completely pulling up the brass part into the gas, but also bringing out only a part of the brass part into the gas or using the black processing composition. Other known methods may be used, such as touching gas bubbles while immersed. When the contact of the black processing composition is performed by application, spraying, or showering, the supply of the black processing composition is temporarily stopped to make contact with the gas.

As is apparent from the above thirteenth to sixteenth embodiments, while the object to be treated is intermittently wetted with the black processing composition during the contact with the black processing composition according to the first aspect, Since the treatment time can be shortened by contacting with a gas containing, the amount of the treatment object per unit time can be increased.

In the present invention, the following inventions are included.

(1) A composition effective for blackening brass, comprising (A) basic copper carbonate, copper hydroxide, copper oxide (II)
Or at least one selected from tetraammine copper (II) salts represented by the formula 12, and [Cu (NH ₃ ) ₄ ] X ₂ (where X is OH, Cl, NO ₃ , NCS, Cu (I) Cl (A monovalent anion composed of ₂ , 1 / 2SO ₄ , HCO ₃ , 1 / 2CO ₃ ) Formula 12 (B) At least one selected from aqueous ammonia, ammonia gas, liquid ammonia, ammonium carbonate, and ammonium hydrogen carbonate And (C) water as a residue.

In the black processing composition of the present invention, black processing can be performed on brass.

[0105]

As described above, according to the first aspect of the present invention, not only can the surface of the object made of brass be blackened, but also the deterioration is small and unnecessary water is introduced. The composition can be easily prepared and replenished, the composition can be easily maintained, the load on the exhaust equipment can be reduced, and the processing can be performed without roughening the surface of the processing object.

According to the second aspect of the present invention, since the range of the processing temperature of the black processing can be widened, the processing amount of the processing target per unit time can be increased, and the black processing composition can be used in a room temperature environment. And no need for heating or cooling. For this reason, simplification of processing equipment and air conditioning equipment and reduction of operating costs can be achieved.

According to the third aspect of the present invention, the processing time can be shortened and the processing amount of the processing target per unit time can be increased because the black processing composition is brought into contact with a gas containing oxygen in a wet state. Can be.

Claims (3)

[Claims] 1. A composition effective for blackening brass, which is selected from: (A) basic copper carbonate, copper hydroxide, copper (II) oxide or a tetraammine copper (II) salt represented by the formula 1. At least one of [Cu (NH ₃ ) ₄ ] X ₂ , wherein X is OH, Cl, NO ₃ , NCS, Cu (I) Cl ₂ , １ ／ SO ₄ , HCO ₃ , 3CO ₃ Formula 1) (B) At least one selected from ammonia water, ammonia gas, liquid ammonia, ammonium carbonate, and ammonium hydrogen carbonate, and (C) water as a residue, The concentration of (copper component, ammonia component) in the composition is (0.2% by weight, 2% by weight), (0.2% by weight, 10% by weight), (1.5% by weight, 20% by weight), (2.5% by weight, 20% by weight), (2.5% by weight, 10% by weight),
(1.5% by weight, 2% by weight). 2. A black processing method comprising: bringing a whole or a part of the surface of an object made of brass into contact with the black processing composition according to claim 1, which is adjusted to a temperature of 10 to 40 ° C. 3. The method according to claim 1, wherein the object to be treated is intermittently contacted with a gas containing oxygen while being brought into contact with the black treatment composition according to claim 1. 3. The black processing method according to claim 2, wherein