JP4292487B2 - Solution for dissolving silver halide - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for melting silver halide, and more specifically, a manufacturing process of a laminated circuit board, a manufacturing process of jewelry or the like containing silver or a silver alloy, a metal bonding process using silver brazing, a halogen from a silver paste. The present invention relates to a technique for dissolving silver halide in industrial production or craft which requires a silver halide dissolution process such as silver halide removal and photographic development process.
[0002]
[Prior art]
Among silver halides, silver chloride, silver bromide, and silver iodide are extremely hardly soluble in an aqueous solution that does not contain a large amount of ligand for silver ions. In the manufacturing and manufacturing processes of industrial products and craft products or parts thereof that contain silver or a silver alloy as at least one component, etching, dissolution, etc. are performed with hydrohalic acid such as hydrochloric acid. Then, silver halide is formed on the surface of the silver or silver alloy part, and it is necessary to dissolve it. Further, as seen in the development process in photographic film, even when silver halide itself is used as a functional material, there are many examples in which a process for dissolving and removing the silver halide is required.
[0003]
In a process that needs to dissolve these silver halides, for example, a jewelry manufacturing process or a metal bonding process using silver brazing, for example, a solution containing cyan, a concentrated ammonia solution, aqua regia or high concentration Solutions containing extremely high concentrations of halogen ions, such as solutions containing halides such as hydrochloric acid, hydrobromic acid, hydriodic acid or potassium iodide, are used. Or, when using a highly corrosive chemical such as those that adversely affect the components due to dissolution, etc., for example in the manufacturing process of laminated circuit boards, photo development processes, etc. A solution containing a complexing agent is used. Alternatively, in addition to thiosulfate, for example, complexing agents such as succinimide and thiourea may be used.
[0004]
[Problems to be solved by the invention]
The solution for dissolving silver halide as described above has a risk of containing a strong acid, a strong alkali, a toxic or suspected carcinogenic agent, or a complex such as thiosulfate. There was a problem that the solution of the agent was slow in dissolution rate. Therefore, the research subject of the present invention is to develop a solution for dissolving silver halide safely and quickly.
[0005]
[Means for Solving the Problems]
The inventors of the present application, as a result of intensive studies to solve the above-mentioned problems in the dissolution of silver halide, have found a completely new complexing agent as a component of the solution for dissolving silver halide, that is, a hydroxyl group. It was found that the silver halide can be dissolved very quickly, easily and safely by using a solution containing an aliphatic phosphine substituted with 1. Thus , the above-mentioned problems have been solved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
That is, the present invention provides a solution for dissolving silver halide, which contains one or more aliphatic phosphines substituted with a hydroxyl group .
[0007]
And phosphine to be used in a solution for dissolving the silver halide of the present invention, one of the hydrogen hydroxymethyl group substituted with a hydroxyl alkyl group, tris hydroxymethyl lower composed only of hydroxyethyl group or hydroxypropyl group Alkylphosphine is preferably used from the viewpoint of cost and stability, and tris (3-hydroxypropyl) phosphine is most preferably used.
[0008]
The solution for dissolving the silver halide of the present invention is most generally used in the form of an aqueous solution, hydroxycarboxylic alkyl phosphinate emission is preferably used. The solution for dissolving the silver halide of the present invention is further used in the form of a solution of an organic solvent such as alcohols, ketones and toluene . Of course, it may also be in the form of a mixed solution or the like of an organic solvent and water such as, for example, alcohol or a ketone.
[0009]
The amount of the phosphine used in the solution for dissolving the silver halide of the present invention has no particular upper and lower limits, and 0.1% to 50% is preferably used, but the dissolution rate decreases as the concentration decreases. In addition, since the stability of the solution is lowered when the concentration is particularly high, 2% to 40% is more preferably used. However, in the case where it may take time for the treatment, for example, in the case where the treatment is carried out by being immersed overnight, the slow treatment speed does not cause a problem, so the concentration is limited to the above. In addition, a more dilute solution may be used.
[0010]
Further, the solution for dissolving the silver halide of the present invention has a fast dissolution rate of silver halide in a weakly acidic to weakly alkaline neutral region, preferably a pH of 5 to 9, and most preferably. Is a pH 7-8 region, but has a good dissolving action in every region from strong acidity to strong alkalinity, so the acidity and alkalinity of the solution can be appropriately changed according to the type and situation of the base material and the purpose of use. Can be used.
[0011]
It is reasonable to use the neutral region solution that has little effect on gemstones, especially when it is desired to dissolve and remove silver halide in the repair of precious metal jewelry in which gemstones are embedded. .
[0012]
When adjusting pH, as a matter of course, acid or alkali is added. For this purpose, for example, inorganic acid such as sulfuric acid, hydrochloric acid and nitric acid, organic acid such as sulfonic acid and carboxylic acid, etc. Known acids and alkalis such as sodium, potassium hydroxide, ammonia, organic amine and the like can be used alone or in combination.
[0013]
In addition, in order to keep the set pH constant, for example, in the case of sodium salts, potassium salts, ammonium salts or polybasic acids such as phosphoric acid, boric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, etc., hydrogen ions are included. Any known pH buffering agent such as an acid salt thereof may be used alone or in an appropriate mixture. Further, a pH indicator can be added to monitor the change in pH of the solution. According to the desired pH range, a known pH indicator may be used in accordance with ordinary usage.
[0014]
A surfactant or a solvent can be further added to the solution for dissolving the silver halide of the present invention. The addition of a surfactant or solvent helps remove the silver halide when it is contaminated with oils and fats and helps the phosphine come into uniform contact with the surface of the object to be processed. Increase processing uniformity and reduce processing time. In addition, the solution can penetrate into fine gaps and the like, and removal unevenness can be prevented.
[0015]
As the surfactant used in the solution for dissolving the silver halide of the present invention, any known surfactant can be used, and these can be used alone or in an appropriate mixture. There is no problem in using the amount according to the general amount of the surfactant used.
[0016]
In the solution for dissolving the silver halide of the present invention, a discoloration inhibitor and a rust inhibitor are further added in order to prevent the surface that has been cleaned by dissolving and removing the silver halide from being discolored and corroded. Can be used.
[0017]
As the discoloration inhibitor and rust inhibitor used in the solution for dissolving the silver halide of the present invention, any known discoloration inhibitor and rust inhibitor can be used, and these can be used singly or appropriately mixed. There is no problem in using the amount according to the general amount of the discoloration inhibitor and the rust inhibitor.
[0018]
In addition, in order to prevent the metal components partially dissolved from the components of the products or parts soaked at the same time from accumulating and reducing the dissolution rate or precipitation of substitution, for example, EDTA, DTPA, citric acid (salt), Known complexing agents such as tartaric acid (salt) and gluconic acid (salt) can be used as a concealing complexing agent, either alone or in appropriate mixture.
[0019]
The solution for dissolving the silver halide of the present invention is generally used by immersing the treatment object in the solution. The solution is applied to the surface of the treatment object by, for example, brushing or spraying. A method such as coating may be employed, and a method such as wiping the surface of the object to be treated by including in a water-absorbing material such as cloth or sponge may be employed.
[0020]
The solution for dissolving the silver halide of the present invention is a manufacturing process of a laminated circuit board, a manufacturing process of jewelry including silver or a silver alloy, a metal bonding process using silver brazing, or a silver halide from a silver paste. It can be widely used in industrial production or craft silver halide dissolution processes that require silver halide dissolution processes, such as removal of photographic materials and photographic development processes.
[0021]
【Example】
Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples, and the silver halide of the present invention is dissolved in accordance with the purpose of dissolving the silver halide. The concentration, composition, usage method, treatment target, and the like for the solution can be arbitrarily changed as appropriate.
[0022]
Example 1
An aqueous solution containing 5% tris (3-hydroxypropyl) phosphine was finely crushed in a mortar into 100 ml of a solution adjusted to pH 7.5 with sulfuric acid, and 400 mg of silver iodide weighed precisely was added, and stirred with a magnetic stirrer. It was about 7 minutes when the time until silver iodide was completely dissolved was measured. On the other hand, when silver iodide was dissolved in the same manner using a commercially available fixing solution for photographic film (Fujifix dissolved at the indicated concentration = thiosulfate solution), it took about 19 minutes for complete dissolution. The phosphine solution had a higher silver halide dissolution rate.
[0023]
Example 2
A commercially available film (Neopan SS-135) was prepared using a solution prepared by adding 10 g / 1 potassium dihydrogen phosphate to an aqueous solution containing 5% tris (3-hydroxypropyl) phosphine and adjusting the pH to 7 with sulfuric acid. After the development process as directed using a commercial developer (microfine), it was stopped with 1.5% aqueous acetic acid and then contained 5% tris (3-hydroxypropyl) phosphine. The film was fixed with an aqueous solution adjusted to pH 6.5 with sulfuric acid, that is, unexposed silver halide in the film was dissolved and removed. The non-photosensitive portion of the film became transparent and could be fixed with the phosphine solution. With respect to the fixing time, the instruction of the commercially available fixing solution was 10 minutes, but with the phosphine solution, complete fixing was possible in 5 minutes.
[0024]
Example 3
A ceramic substrate obtained by joining a copper foil with an aluminum-based ceramic plate with a silver-copper-based silver brazing material was patterned using an alkali development type dry film, and copper was etched with a 35% iron chloride solution. An aqueous solution containing 6% tris (3-hydroxypropyl) phosphine and 0.2% nonionic surfactant (polyoxyethylene alkyl ether) and adjusted to pH 5.5 with sulfuric acid at a temperature of 20 ° C. It was immersed for 1 minute to remove silver chloride formed on the silver solder in the copper etching process. Silver chloride could be completely removed without peeling off the resist. On the other hand, 5% ammonia water was used in the step of removing silver chloride, and the resist was peeled off when immersed for 2 minutes.
[0025]
Example 4
In order to craft jewelry of silver alloy containing 3% copper (sterling silver), it was joined with silver solder. The joint was oxidized and discolored blackish by heat. Although the discoloration was removed by immersion in agricultural hydrochloric acid, the surface was covered with silver chloride. Immerse in an aqueous solution containing 5% tris (hydroxymethyl) phosphine and 0.1% nonionic surfactant (polyoxyethylene nonylphenyl ether) and adjusted to pH 9 with potassium dihydrogen phosphate for 2 minutes As a result, silver chloride was completely removed.
[0026]
【The invention's effect】
The solution for dissolving the silver halide of the present invention does not require dangerous chemicals such as strong acid and cyanide or toxic chemicals, and can dissolve silver halide very quickly and easily. Furthermore, since the solution exhibits the effect in a wide pH range, it can be used by appropriately changing the pH according to the purpose such as preventing dissolution of the resist.

Claims (3)

A solution for dissolving silver halide, characterized by containing one or more of tris (hydroxymethyl) phosphine, tris (2-hydroxyethyl) phosphine or tris (3-hydroxypropyl) phosphine. Furthermore, it contains one or more of acid or alkali, pH adjuster, pH buffer, pH indicator, surfactant, discoloration inhibitor, rust inhibitor, and concealing complexing agent. Item 2. A solution for dissolving the silver halide according to item 1 . A product which has been subjected to silver halide dissolution treatment using the solution for dissolving silver halide according to claim 1 or 2 .