JP6932371B2 - Appearance protectant and metal body treated with the appearance protectant - Google Patents

Description

The present invention relates to a metal appearance protectant, and more specifically, an appearance that suppresses discoloration and / or corrosion of a specific metal plating film existing as an outermost layer on a specific base metal to maintain the appearance. Regarding protective agents. The present invention also relates to a metal body treated with the appearance protective agent and a method for treating the metal body treated with the appearance protective agent.

Gold-plated coatings and gold alloy-plated coatings are excellent in electrical characteristics, mechanical characteristics, solderability, corrosion resistance, etc., and are therefore often used as the outermost layer in connectors and printed circuit boards that require high reliability. .. Further, in recent years, the density of electronic devices has been increasing, and the reliability required for gold (alloy) plated parts has become higher.

On the other hand, for economic reasons due to the price of gold, thinning of gold plating films and gold alloy plating films is progressing, and the pinholes of the films are increasing exponentially with the thinning.
As a result, corrosive substances invade from the pinholes and the like over time, corroding the base metal of the gold (alloy) plating film, and depositing corrosion products on the surface of the gold plating film and the gold alloy plating film. The appearance of the gold plating film or the gold alloy plating film changes with time due to the influence of the base metal, which causes a decrease in reliability. Further, such a phenomenon not only spoils the appearance but also causes problems such as an increase in contact resistance, a short circuit of a circuit, and a disconnection.

Further, since the silver plating film and the silver alloy plating film are excellent in electrical characteristics, mechanical characteristics, solderability, etc., they are often used in electric devices such as connectors, lead frames, and various switches.
Furthermore, in recent years, light emitting diode (LED) lighting has rapidly become widespread as a new lighting alternative to incandescent lamps and fluorescent lamps, and LED lighting is equipped with a reflector in order to efficiently irradiate LED light. .. The high-brightness silver (alloy) plating film has excellent reflection characteristics of LED light, and is widely used for this reflector.

However, silver and silver alloys are corroded and discolored by producing silver sulfide, etc. by reacting with sulfur compounds in the atmosphere, and their electrical characteristics deteriorate in electrical device applications, and they are also used in reflectors. Then, there is a problem that the light reflection characteristic is deteriorated.

Further, a palladium plating film or a palladium alloy plating film is also used as the outermost layer of various metal bodies because it is excellent in electrical properties, mechanical properties, corrosion resistance and the like.
However, palladium and palladium alloys also discolor when they react with organic compounds, sulfur compounds, etc. in the atmosphere, and the above characteristics are deteriorated.

Chromate treatment and treatment with a surface treatment agent are known as means for avoiding such problems of corrosion and discoloration. Chromate treatment attempts to protect the appearance by forming a film of a chromium compound on a metal film. The treatment with a surface treatment agent is intended to protect the appearance by immersing a metal body (material) in a solution containing an organic compound and forming an organic film on the surface (for example, Patent Documents 1 to 4). ..

However, since chromate treatment uses hexavalent chromium, its use is greatly restricted due to its environmental impact and toxicity. Further, the organic protective film made of the surface treatment agent has a problem that it is decomposed by heat treatment in the mounting process or heat generated during use, and its effectiveness is impaired.

Patent Documents 1 to 4 disclose surface treatment agents using organic compounds such as benzotriazole-based compounds, tetrazole-based compounds, and thiol-based compounds. However, in these patent documents, the heat treatment of the sample assuming soldering is not performed before the corrosion test, and the heat resistance of the surface treatment agent itself and the heat resistance of the metal surface treated with the surface treatment agent are not performed. No consideration is given to the properties and the change in appearance due to the "corrosion test after heat treatment".

Japanese Unexamined Patent Publication No. 2006-351568 Japanese Unexamined Patent Publication No. 2008-405215 Japanese Unexamined Patent Publication No. 2011-241428 Japanese Unexamined Patent Publication No. 2012-172190

The present invention has been made in view of the above background technology, and the subject thereof is discoloration of a silver plating film, a silver alloy plating film, a gold plating film, a gold alloy plating film, a palladium plating film, and a palladium alloy plating film. It is an object of the present invention to provide an appearance protective agent which prevents plating and corrosion, maintains the appearance, and has excellent heat resistance.

As a result of diligent studies to solve the above problems, the present inventor has made a benzotriazole ring compound and a specific amine compound and / or ammonium compound in combination as essential components to obtain an appearance protective agent. The appearance protective agent changes the appearance of "silver (alloy) plating film", "gold (alloy) plating film", and "palladium (alloy) plating film" due to discoloration or corrosion when a specific metal is used as the base metal. The present invention has been completed by finding that it can be suppressed even if the heat treatment is performed after the treatment.

That is, the present invention uses at least one metal selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys as a base metal, and uses a silver plating film, a silver alloy plating film, and gold plating. An appearance protective agent for maintaining the appearance of a film, a gold alloy plating film, a palladium plating film, or a metal body having a palladium alloy plating film on the outermost layer by suppressing discoloration and / or corrosion of the outermost layer.
Provided is an appearance protective agent containing a benzotriazole ring compound and an amine compound represented by the following formula (2) and / or an ammonium compound having an ammonium cation represented by the following formula (3). It is a thing.

In formula (2), R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁶ , R ⁷ and R ⁸ may be bonded to form a ring. However, this excludes cases where all of ^{R 6} , R ⁷ and R ^{8 are hydrogen atoms.}

In formula (3), R ⁹ , R ¹⁰ and R ¹¹ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁹ , R ¹⁰ and R ¹¹ may be bonded to form a ring. However, this excludes cases where all of ^{R 9} , R ¹⁰ and R ^{11 are hydrogen atoms.}

Further, the present invention uses at least one metal selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys as a base metal, and uses a silver plating film, a silver alloy plating film, and gold plating. The surface of the film, the gold alloy plating film, the palladium plating film, or the metal body having the palladium alloy plating film as the outermost layer is treated with the above-mentioned appearance protective agent to suppress discoloration and / or corrosion of the outermost layer. Provided is a metal body characterized in that the appearance is maintained.

Further, the present invention uses at least one metal selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys as a base metal, and uses a silver plating film, a silver alloy plating film, and gold plating. The surface of the film, the gold alloy plating film, the palladium plating film, or the metal body having the palladium alloy plating film as the outermost layer is treated with the above-mentioned appearance protective agent to suppress discoloration and / or corrosion of the outermost layer. The present invention provides a method for treating a metal body, which is characterized in that the appearance is maintained.

In addition, in this specification, the term may be used as follows.

Silver plating film and silver alloy plating film are collectively called "silver (alloy) plating film", gold plating film and gold alloy plating film are collectively called "gold (alloy) plating film", palladium plating film and palladium alloy plating film. May be collectively referred to as "palladium (alloy) plating film".

When copper and copper alloy are collectively referred to as "copper (alloy)", nickel and nickel alloy are collectively referred to as "nickel (alloy)", and palladium and palladium alloy are collectively referred to as "palladium (alloy)". There is.

"At least one metal selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys" may be described as "specific base metal".

"Silver plating film, silver alloy plating film, gold plating film, gold alloy plating film, palladium plating film, palladium alloy plating film" may be described as "target specific plating film".

The "amine compound represented by the formula (2)" may be described as a "specific amine compound", and the "ammonium compound having an ammonium cation represented by the formula (3)" may be described as a "specific ammonium compound".

According to the present invention, it is possible to solve the above problems and problems, prevent discoloration and corrosion of the target specific plating film, maintain the appearance, and provide an appearance protective agent having excellent heat resistance. ..
That is, by treating the surface of the target-specific plating film formed on the specific base metal with the appearance protective agent of the present invention, it is possible to suitably prevent discoloration due to aging and changes in appearance due to corrosion. In particular, even if the surface of any "target-specific plating film" is treated, it is possible to suitably prevent changes in appearance over time.

Further, the appearance protectant itself of the present invention and the metal surface treated with the appearance protectant have excellent heat resistance, and the surface of the metal body treated with the appearance protectant of the present invention (the surface of the target specific plating film) is , It has a sufficient appearance maintenance effect even after heat treatment assuming soldering.
In the present invention, the appearance-maintaining effect (change in appearance with time) is confirmed by an accelerated deterioration test by exposing to sulfur dioxide gas and hydrogen sulfide gas, which are representative of corrosive substances in the atmosphere, respectively.

If the appearance protectant itself or the metal surface treated with the appearance protectant does not have heat resistance, a sufficient appearance maintenance effect cannot be obtained over time after the heat treatment. In many cases, the product is made after soldering, but in such a case, if the appearance cannot be maintained over time, the electrical characteristics will deteriorate and the reliability will be poor in electrical device applications. It ends up. In addition, the light reflection characteristic is deteriorated in the use of a reflector.
According to the present invention, for example, even after performing the "heat treatment assuming soldering" described in the examples, the appearance is maintained by preventing the appearance of the "target-specific plating film" from being discolored or corroded over time. can.

Further, the appearance protectant of the present invention is water-soluble and does not contain an organic solvent or a heavy metal as an essential component, so that it is excellent in safety and environmental characteristics.

Further, the metal body treated with the appearance protective agent of the present invention has good wire bonding characteristics, solder wettability, etc., in addition to maintaining the appearance as described above, and there is almost no increase in contact resistance.
Further, since there is almost no decrease in reflectance with time, reliability can be maintained when the metal body is an electric device, and light reflection characteristics can be maintained in good condition when the metal body is a reflector.

Hereinafter, the present invention will be described, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and carried out.

Since all of the exemplified compounds described in the present specification are dissolved in water and become a component of an appearance protective agent, any of the exemplified compounds which can be a salt shall also mean the salt thereof. .. In addition, it is assumed that a solution of an appearance protectant that has undergone salt exchange with other compounding ingredients is also included (meaning).

The appearance protectant of the present invention is a silver-plated film using at least one metal (specific base metal) selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys as a base metal. Suppresses discoloration and / or corrosion of the outermost layer of a metal body having a silver alloy plating film, a gold plating film, a gold alloy plating film, a palladium plating film, or a palladium alloy plating film (target specific plating film) as the outermost layer. It is an appearance protective agent that maintains the appearance.
The appearance protectant of the present invention is an ammonium compound having a benzotriazole ring compound, an amine compound represented by the formula (2) (specific amine compound), and / or an ammonium cation represented by the formula (3). Specific ammonium compound) is contained.

<Benzotriazole ring compound>
The "benzotriazole ring compound" contained in the appearance protectant of the present invention refers to benzotriazole (CAS registration number: 95-14-7) or a compound in which one or more hydrogen atoms of benzotriazole are substituted. ..

Examples of the benzotriazole ring compound include a compound represented by the following formula (1).

In the formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are hydrogen atom, hydroxyl group, halogen atom (F, Cl, Br, I), carboxyl group, alkyl group and alkoxy group, respectively. Is.

The number of carbon atoms of the alkyl group and the alkoxy group is preferably 1 or more and 8 or less, preferably 1 or more and 6 or less, and particularly preferably 1 or more and 4 or less.
The alkyl group or alkoxy group may be linear or have a side chain (branch).
Alkyl groups and alkoxy groups may be further substituted.

Further, ^{among R 1 to} R ⁵ , 3 or 4 hydrogen atoms (that is, 1 or 2 hydrogen atoms of benzotriazole are substituted) are likely to exert the effect of the present invention. It is preferable in terms of points, ease of synthesis / availability, cost, and the like.

Further, when the benzotriazole ring compound has a hydroxyl group, a carboxyl group, or both, it is presumed that an interaction with a specific amine compound or a specific ammonium compound (as described later, a complex is formed). This is preferable because the effect of preventing discoloration and corrosion is enhanced and the heat resistance is easily improved.

Specific examples of the benzotriazole ring compound include 1,2,3-benzotriazole, hydroxybenzotriazole, chlorobenzotriazole, carboxybenzotriazole, tolyltriazole, ethylbenzotriazole, propylbenzotriazole, isopropylbenzotriazole, and butylbenzotriazole. , Isobutyl benzotriazole, pentyl benzotriazole, isopentyl benzotriazole, dihydroxy benzotriazole, chlorohydroxy benzotriazole, carboxyhydroxy benzotriazole, methyl hydroxy benzotriazole, ethyl hydroxy benzotriazole, hydroxypropyl benzotriazole, hydroxyisopropyl benzotriazole, butyl hydroxy Benzotriazole, hydroxyisobutylbenzotriazole, hydroxypentylbenzotriazole, hydroxyisopentylbenzotriazole, carboxychlorobenzotriazole, chloromethylbenzotriazole, ethylchlorobenzotriazole, chloropropylbenzotriazole, chloroisopropylbenzotriazole, butylchlorobenzotriazole, chloro Isobutylbenzotriazole, chloropentylbenzotriazole, chloroisopentylbenzotriazole, carboxymethylbenzotriazole, carboxyethylbenzotriazole, carboxypropylbenzotriazole, carboxyisopropylbenzotriazole, carboxybutylbenzotriazole, carboxyisobutylbenzotriazole, carboxypentylbenzotriazole, Examples thereof include carboxyisopentylbenzotriazole.

In the specific examples of the above-mentioned benzotriazole ring compound, the description of "benzotriazole" is "1,2,3-benzotriazole". Further, the bonding position of the substituent to the benzotriazole ring may be anywhere in ^{R 1 to} R ^5.

In the appearance protection agent of the present invention, one type of benzotriazole ring compound may be used alone, or two or more types may be used in combination.

The concentration of the benzotriazole ring compound (total concentration when two or more kinds are used in combination) is not particularly limited, but is preferably 0.001 g / L or more and 100 g / L or less, and 0.05 g / L or more and 50 g / L or less. More preferably, 0.01 g / L or more and 10 g / L or less is particularly preferable.
If the concentration of the benzotriazole ring compound is too high, stains are likely to occur on the surface of the target-specific plating film during drying immediately after treatment with an appearance protectant, which may cause an appearance abnormality. Further, the appearance protective agent may become unstable as a solution, and salts may easily precipitate.
On the other hand, if the concentration of the benzotriazole ring compound is too low, the above-mentioned effect of the present invention may not be obtained, for example, a sufficient appearance-maintaining effect may not be obtained.

<Amine compound represented by the formula (2) and an ammonium compound having an ammonium cation represented by the formula (3)>
In formula (2), R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁶ , R ⁷ and R ⁸ may be bonded to form a ring. However, this excludes cases where all of ^{R 6} , R ⁷ and R ^{8 are hydrogen atoms.}
In the case of a compound containing a plurality of N atoms in the molecule, when any one ^{N atom is regarded as an N atom bonded to R 6 to} R ⁸ , if the above requirements are satisfied, the formula (2) ) ”.

When R ^{6 to} R ⁸ are optionally substituted hydrocarbon groups, the number of carbon atoms is preferably 12 or less, more preferably 8 or less, and particularly preferably 6 or less.
The hydrocarbon group which may be substituted may be a straight chain or have a side chain (branch). Further, it may have an annular portion, and the annular portion may be an aliphatic ring or an aromatic ring.

When the hydrocarbon group is substituted, specific examples of the substituent include a hydroxyl group, an amino group (primary amino group, a secondary amino group, a tertiary amino group), an alkoxy group and the like.

The amine compound represented by the formula (2) is a primary amine compound ^{when two of R 6 to} R ⁸ are hydrogen atoms, and a secondary amine compound when one of R ^{6 to} R ⁸ is a hydrogen atom. When ^{none of R 6 to} R ⁸ is a hydrogen atom, it is a tertiary amine compound.
In the case of a tertiary amine compound, it is preferable that one or more of ^{R 6 to} R ^{8 have a hydroxyl group from the viewpoint of ensuring water solubility.}

Specific examples of the amine compound (specific amine compound) represented by the formula (2) include monoethanolamine, diethanolamine, triethanolamine, propanolamine, 2-amino-2-methyl-1-propanol, and 1-dimethylamino. -2-propanol, DL-1-amino-2-propanol, N- (2-hydroxypropyl) ethylenediamine, 2- (2-aminoethylamino) ethanol, 2- (2-aminoethoxy) ethanol, tris (hydroxymethyl) ) Aminomethane, 3-amino-1,2-propanediol, DL-2-amino-1-butanol, 1-amino-2-butanol, 5-amino-1-pentanol, DL-2-amino-1- Propanol, 4-amino-1-butanol, 6-amino-1-hexanol, 2-amino-1,3-propanediol, N- (3-aminopropyl) diethanolamine, 3-amino-1-butanol, N-butyl Diethanolamine, 2- (butylamino) ethanol, 2- (tert-butylamino) ethanol, N-tert-butyldiethanolamine, N, N'-bis (2-hydroxyethyl) ethylenediamine, 3-diethylamino-1-propanol, 2 -(Dimethylamino) ethanol, 1-dimethylamino-1-propanol, diisopropanolamine, 2- (diisopropylamino) ethanol, 2- (dimethylamino) -2-methyl-1-propanol, 4-dimethylamino-1- Butanol, 6-dimethylamino-1-hexanol, 3- (diethylamino) -1,2-propanediol, 3-dimethylamino-2,2-dimethyl-1-propanol, 3- (dimethylamino) -1,2- Propanediol, 4-diethylamino-2-butin-1-ol, 2-[[2- (dimethylamino) ethyl] methylamino] ethanol, 5-diethylamino-1-pentanol, 2- (ethylamino) ethanol, N -Ethyldiethanolamine, 4-ethylamino-1-butanol, N- (3-hydroxypropyl) ethylenediamine, 1,3-diamino-2-propanol, 2-[(hydroxymethyl) amino] ethanol, 2- (isopropylamino) Ethanol, 3- (isopropylamino) propanol, 4- (isopropylamino) butanol, 5- (isopropylamino) pentanol, N-lauryldiethanolamine, 2- (me Tylamino) ethanol, N-methyldiethanolamine, 3-methylamino-1,2-propanediol, stearyldiethanolamine, DL-valinol, bis (2-isopropoxyethyl) amine, N- (tert-butoxycarbonyl) -2,2 -Dimethyl-1,3-propanediamine, 1-aminodecane, diamilamine, 1- (2-hydroxyethyl) piperazine, N, N-dimethyl-1,3-propanediamine, N-methyl-1,3-diaminopropane, Triisopropanolamine, N- (2-aminoethyl) piperazine, tropin, 3-amino-1-phenylbutane, 4-phenylbutylamine, N- (3-aminopropyl) -N-methylaniline, 1-aminoindan, 2 -Aminoindane, N-allylbenzylamine, 1-adamantanamine, 3-amino-3-phenyl-1-propanol, 4-tert-butylcyclohexylamine, N-isopropylbenzylamine, 3-benzyloxazolidine, 3-benzylamino -1-propanol, 2,2'-bipiperidin, 4-sec-butylcyclohexylamine, 4-butylcyclohexylamine, 3,3'-bipiperidin, N-benzyl-1,3-propanediamine, cumylamine, N, N- Diethylcyclohexylamine, diisoamylamine, dicyclohexylamine, 1- (2-dimethylaminoethyl) -4-methylpiperazine, N- (3-aminopropyl) morpholine, N- (2-hydroxyethyl) morpholine, morpholine, diethylenetriamine, Triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,3-bis (aminomethyl) cyclohexane, polyethyleneimine, arginine, glucamine, N-methyl-D-glucamine, N, N, N', N'-tetrakis Examples thereof include (2-hydroxyethyl) ethylenediamine, N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine and the like.

The ammonium cation in the ammonium compound (specific ammonium compound) having the ammonium cation represented by the formula (3) has a structure in which a ^{proton (H +) is added to the amine compound (specific amine compound) represented by the formula (2).} be.

In formula (3), R ⁹ , R ¹⁰ and R ¹¹ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁹ , R ¹⁰ and R ¹¹ may be bonded to form a ring. However, this excludes cases where all of ^{R 9} , R ¹⁰ and R ^{11 are hydrogen atoms.}

In the formula (3), ^{preferable examples of R 9 to} R ¹¹ are the same as those ^{of R 6 to} R ⁸ in the formula (2). As a specific example of the ammonium cation represented by the formula (3), an ammonium cation having a structure in which a ^{proton (H +) is added to the amine compound (specific amine compound) represented by the formula (2) can be mentioned.}

As a specific example of the counter anion of the ammonium cation represented by the formula (3),
Sulfate ion, sulfite ion, nitrate ion, nitrite ion, phosphate ion, phosphite ion, phosphonate ion, fluoride ion, chloride ion, bromide ion, iodide ion, hypochlorite ion, chlorite Ion, chlorate ion, perchlorate ion, hypobromine acid ion, bromine acid ion, bromine acid ion, perbromate ion, hypoioyate ion, iodoate ion, iodate ion, perioitate ion , Metaborate ion, carbonate ion, hydroxide ion, organic carboxylic acid ion and the like.

In the appearance protectant of the present invention, only the amine compound represented by the formula (2) (specific amine compound) may be used, or the ammonium compound having an ammonium cation represented by the formula (3) (specific ammonium) may be used. Compound) alone may be used, or a specific amine compound and a specific ammonium compound may be used in combination.
The specific amine compound may be used alone or in combination of two or more. The specific ammonium compound may be used alone or in combination of two or more.

The concentration of the specific amine compound and the specific ammonium compound (when two or more kinds are used in combination, the total concentration of all the specific amine compounds and the specific ammonium compounds) is not particularly limited, but is 0.001 g / L or more and 100 g. / L or less is preferable, 0.05 g / L or more and 50 g / L or less is more preferable, and 0.01 g / L or more and 10 g / L or less is particularly preferable.
If the above concentration is too high, stains are likely to occur on the surface of the target-specific plating film during drying immediately after treatment with an appearance protective agent, which may cause an appearance abnormality. Further, the appearance protective agent may become unstable as a solution, and salts may easily precipitate.
On the other hand, if the concentration is too low, the above-mentioned effect of the present invention may not be obtained, for example, a sufficient appearance-maintaining effect cannot be obtained.

The concentration of the specific amine compound and the specific ammonium compound (when two or more kinds are used in combination, the total concentration of all the specific amine compounds and the specific ammonium compounds) is the molar concentration of the benzotriazole ring compound (the concentration). When compared with the total concentration) when two or more kinds are used in combination, it is preferable that the concentration is about the same.
Specifically, the value obtained by dividing the "molar concentration of the specific amine compound and the specific ammonium compound" by the molar concentration of the benzotriazole ring compound is preferably 0.6 or more, and preferably 0.8 or more. It is more preferable, and it is particularly preferable that it is 0.9 or more. Further, it is preferably 1.4 or less, more preferably 1.2 or less, and particularly preferably 1.1 or less.
By doing so, the benzotriazole ring compound and the specific amine compound or the specific ammonium compound can easily form a complex, and the above-mentioned effects of the present invention can be easily exerted.

<Water>
The appearance protectant of the present invention is an aqueous solution obtained by dissolving the above-mentioned components in water at the above-mentioned concentration (however, the inclusion of a small amount of an organic solvent in the liquid is not excluded). The dissolution method is not particularly limited, and a known method is used. The order of dissolution is not particularly limited, and a known method is used. As the water, it is preferable to use pure water such as ion-exchanged water (deionized water) and distilled water.

<pH>
The pH of the appearance protectant of the present invention is not particularly limited, but is preferably pH 5 or higher at room temperature. If the pH is too low, the metal of the target-specific plating film will dissolve, causing deterioration of corrosion resistance and abnormal appearance. Regarding the adjustment of pH, as the benzotriazole ring compound, a benzotriazole ring compound having a weakly acidic functional group such as a carboxyl group or a hydroxyl group may be used also as a pH buffer, or a pH buffer may be added separately. You may.

The pH buffer to be added separately is not particularly limited as long as it can mitigate pH fluctuations without adversely affecting the appearance protective agent. Specific examples thereof include boric acid, phosphoric acid, pyrophosphate, morpholine ethanesulfonic acid and the like.
One type of pH buffer may be used alone, or two or more types may be used in combination.

The concentration of the pH buffer agent separately added to the appearance protectant of the present invention is preferably 0.01 g / L or more and 100 g / L or less, and particularly preferably 0.1 g / L or more and 10 g / L or less.
If the pH buffer concentration is too high, stains may occur on the surface of the target-specific plating film, and the contact resistance and wire bonding characteristics may be adversely affected. On the other hand, if the pH buffering agent concentration is too low, the pH buffering effect cannot be sufficiently obtained and it is not practical.

<Surfactant>
A surfactant may be added to the appearance protectant of the present invention, if necessary. The surfactant is not particularly limited as long as it is a well-known surfactant and does not adversely affect the appearance protective agent, and is a nonionic surfactant, an anionic surfactant, an amphoteric surfactant or a cationic surfactant. Is used.
One type of surfactant may be used alone, or two or more types may be used in combination.

The nonionic surfactant is not particularly limited, but is, for example, a polyalkylene glycol type nonionic surfactant such as polyethylene glycol, polypropylene glycol, block copolymer of polyethylene glycol and polypropylene glycol; nonylphenol polyalkoxylate, α-naphthol. Ether-type nonionic surfactants such as polyalkoxylate, dibutyl-β-naphthol polyalkoxylate, and styrene phenolpolyalkoxylate; octylamine polyalkoxylate, hexynylamine polyalkoxylate, linoleylamine polyalkoxylate and the like. Amine-type nonionic surfactant; and the like.

The anionic surfactant is not particularly limited, but for example, an alkyl sulfate such as sodium lauryl sulfate; a polyoxyethylene alkyl ether sulfate such as polyoxyethylene nonyl ether sulfate; and a polyoxyethylene alkylphenyl ether sulfate. Alkylbenzene sulfonate; etc.

The amphoteric tenside is not particularly limited, but for example, 2-undecyl-1-carboxymethyl-1-hydroxyethyl imidazolium betaine, N-stearyl-N, N-dimethyl-N-carboxymethyl betaine, and lauryl dimethyl. Amine oxide and the like can be mentioned.

The cationic surfactant is not particularly limited, and examples thereof include lauryltrimethylammonium salt, lauryldimethylammonium betaine, laurylpyridinium salt, oleylimidazolium salt, and stearylamine acetate.

Among the above surfactants, a nonionic surfactant or an amphoteric surfactant is preferable. These surfactants may be used alone or in admixture of two or more of the same or different species.

The concentration of the surfactant in the appearance protectant of the present invention (total concentration when two or more kinds are used in combination) is preferably 0.01 g / L or more and 10 g / L or less, but if the desired performance is exhibited. Well, the concentration is not particularly limited.

<Target specific plating film, specific base metal, application>
The appearance protective agent of the present invention exerts the above-mentioned effect of the present invention when the outermost layer is the above-mentioned "target-specific plating film".
Specifically, the outermost layer, the "target specific plating film", is a silver plating film, a silver-palladium alloy plating film, a gold plating film, a gold-cobalt alloy plating film, a gold-nickel alloy plating film, a gold-silver alloy plating film, and gold. A tin alloy film, a palladium plating film, a palladium cobalt alloy plating film, or a palladium nickel alloy plating film is particularly preferable because the effects of the present invention are particularly exhibited.

Regarding the film thickness of the target-specific plating film when the appearance protective agent of the present invention is used, when the target-specific plating film is a silver (alloy) plating film, it is preferably 0.01 μm or more and 1000 μm or less, and 0.1 μm or more and 100 μm or less. Is more preferable, and 1 μm or more and 10 μm or less is particularly preferable.
When the target specific plating film is a gold (alloy) plating film, it is preferably 0.0001 μm or more and 100 μm or less, more preferably 0.001 μm or more and 10 μm or less, and particularly preferably 0.01 μm or more and 1 μm or less.
When the target specific plating film is a palladium (alloy) plating film, it is preferably 0.0001 μm or more and 100 μm or less, more preferably 0.001 μm or more and 10 μm or less, and particularly preferably 0.01 μm or more and 1 μm or less.

In particular, in the case of a gold (alloy) plating film, the upper limit is often set to the above or less because of the great advantage of thinning as described above. Generally, a thin film tends to cause pinholes. Since the present invention can cope with the pinhole and maintain the electrical performance and appearance, it is desirable that the upper limit is equal to or less than the above.
On the other hand, when the lower limit is equal to or higher than the above, various performances as a metal plating film are likely to be exhibited.

The base metal (specific base metal) of the outermost layer plating film in the present invention can be appropriately selected according to the required characteristics of each application such as a connector, a printed substrate, and a reflector, and is not limited in any way, but is limited to pure copper, beryllium copper, and the like. Various copper (alloys) (coatings) such as brass, phosphorus bronze, copper-iron alloys, Corson alloys; various nickels (alloys) (coatings) such as nickel plating film, nickel phosphorus plating film, 42 alloy, palladium nickel plating film; Various palladium (alloy) films such as a plating film, a palladium phosphorus plating film, a palladium nickel plating film, a palladium cobalt plating film, and a palladium silver plating film; are preferable.

Here, the above-mentioned "various copper (alloys) (films)" are not limited to those formed by plating, and are not plating films, such as copper (alloy) foils, copper (alloy) plates, and copper (alloy) wires. , Copper (alloy) circuit, copper (alloy) ingot, etc., may be various copper (alloy) in general, or may be various copper (alloy) film which is a plating film.
The same applies to "various nickel (alloy) (film)" and "various palladium (alloy) (film)".

The reason why the specific base metal is preferable as the base of the target specific plating film is that the specific base metal is a metal that is often used for applications such as connectors, printed substrates, and reflectors. In addition, the appearance protectant of the present invention causes a phenomenon that corrosion products are deposited on the surface through pinholes of the gold (alloy) plating film, particularly when the target specific plating film is a gold (alloy) plating film. The reason is that it can be prevented particularly preferably.
For example, the thinning of the gold (alloy) plating film has progressed due to the soaring price of gold, and as a result of the increase in the pinholes of the film due to the thinning, the pinholes of the gold (alloy) plating film have increased over time. When a corrosive substance (sulfurous acid gas, hydrogen sulfide gas, etc.) invades from the above, the specific base metal is corroded, and a corrosion product is deposited on the surface of the gold (alloy) plating film.

When the appearance protective agent of the present invention is used, when the base is the specific base metal, "the change with time of the surface of the gold (alloy) plating film due to the precipitation of the corrosion products" is suppressed, and the contact resistance is increased. Not only can it prevent problems such as short circuits and disconnections in the circuit, but it also improves reliability by suppressing changes in appearance.

The appearance protective agent of the present invention can be suitably used when the outermost layer plating film is the "target specific plating film", but the plating method of the target specific plating film is wet plating such as electrolytic plating and electroless plating. It can be performed by a known method such as CVD, dry plating of PVD, etc., and is not limited in any way.

<Treatment method with appearance protectant>
Further, in the present invention, the surface of a metal body having the above-mentioned target specific plating film as the outermost layer is treated with the above-mentioned appearance protective agent using the above-mentioned specific base metal as a base, and the outermost layer is discolored and / or It is also a method for treating a metal body, which is characterized in that corrosion is suppressed and the appearance is maintained.

Examples of the method for treating the metal body include a method of directly immersing the metal body in the appearance protective agent, a method of applying the appearance protection agent to the metal body, a method of spraying the appearance protection agent with a spray gun, and the like.
Although not particularly limited, the method of direct immersion is particularly preferable. As the dipping conditions, a method of immersing at 10 ° C. to 60 ° C. for 1 second or longer is preferable, and a method of immersing at 30 ° C. to 50 ° C. for 2 seconds to 1 minute is particularly preferable.
After the treatment with the appearance protective agent, it may be washed with water, but since the components of the appearance protective agent are water-soluble, it is preferable to remove the droplets of the appearance protective agent with an air gun or the like without carrying out the washing with water.

<Metal body>
The present invention uses at least one metal (specific base metal) selected from the group consisting of copper, copper alloys, nickel, nickel alloys, palladium, and palladium alloys as a base metal, and uses a silver plating film and a silver alloy plating film. The surface of a metal body having a gold plating film, a gold alloy plating film, a palladium plating film, or a palladium alloy plating film (target specific plating film) as the outermost layer is treated with the above-mentioned appearance protective agent of the present invention. It is also a metal body characterized in that the outermost layer is in a state in which discoloration and / or corrosion is suppressed and the appearance is maintained.

<Action / Principle>
Although the action / principle of the appearance protective agent of the present invention that can sufficiently prevent discoloration and corrosion of the target-specific plating film and exhibit excellent heat resistance is not clear, the following can be considered. However, the present invention is not limited to the following scope of action / principle.

In the appearance protectant of the present invention, it is considered that the benzotriazole ring compound and the specific amine compound or the specific ammonium compound form a complex. As a result, it is considered that the apparent molecular weight becomes larger, the water solubility becomes lower, and a high corrosion resistance effect is exhibited.

The plating film treated with the appearance protective agent of the present invention maintains almost the same corrosion resistance as when it is not subjected to a heat load even when it is subjected to a heat load such as reflow in a soldering operation. Is possible.
The reason for this is that the apparent molecular weight increases due to the formation of a complex of the benzotriazole ring compound and the specific amine compound or the specific ammonium compound, the boiling point becomes higher than when each is used alone, and the appearance due to heat load is increased. This is probably because the protective agent is less likely to volatilize.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples as long as the gist thereof is not exceeded.

Examples 1 to 24, Comparative Examples 1 to 22
<Preparation of appearance protectant>
The benzotriazole ring compound (or control compound) shown in Table 1 was dissolved in 5 g / L, respectively, and the specific amine compound or specific ammonium compound shown in Table 1 was dissolved in 5 g / L, respectively, in pure water.
"-" In "Table 1" indicates that the corresponding compound is not contained in the appearance protective agent.

Next, 1 g / L of potassium hydrogen phosphate was dissolved as a pH buffer to adjust the pH to 7.0. An aqueous potassium hydroxide solution was used to raise the pH, and phosphoric acid was used to lower the pH.

<Plating process>
The plating process is shown in Table 2. The phosphor bronze plate was subjected to degreasing, electrolytic nickel strike plating, electrolytic bright nickel plating, and electrolytic gold strike plating.
Then, the outermost metal plating film was formed by various plating treatments shown in Table 3.

<Treatment with appearance protectant>
The various plating samples prepared in the above plating step were immersed in the appearance protective agents corresponding to Examples 1 to 24 and Comparative Examples 1 to 22 shown in Table 1 at 25 ° C. for 5 seconds, and each of them was treated. rice field. After the treatment, the droplets adhering to the air gun were removed without washing with water.

<Heat treatment of various plating samples after treatment with appearance protectant>
The various plating samples treated with the appearance protective agents of Examples 2 to 24 and Comparative Examples 2 to 20 were heat-treated assuming solder treatment on a metal body (product) having a metal film on the outermost layer. A reflow furnace (RF-430-MZ, manufactured by Nippon Pulse Technology Laboratory Co., Ltd.) was used for the heat treatment, and the heat treatment was performed three times under the following conditions.

Conveyor speed: 240 mm / min Conveyor length: 980 mm
Set temperature: 160 ° C-170 ° C-200 ° C-260 ° C
(Maximum temperature reached 260 ° C, 200 ° C or higher for 106 seconds, 250 ° C or higher for 24 seconds)

No heat treatment was performed on Example 1 and Comparative Example 1.

<Evaluation test method>
All the samples of Examples 1 to 24 and Comparative Examples 1 to 22 were subjected to a sulfur dioxide gas test, a hydrogen sulfide gas test and a salt spray test, and the degree of corrosion or discoloration of the tested samples was visually observed. Evaluated in.

◯: No corrosion / discoloration △: Slight corrosion / discoloration is observed ×: Severe corrosion / discoloration is observed

<< Sulfur dioxide gas test >>
Sulfurous acid gas test (concentration: 25 volume ppm, temperature: 40 ° C., relative humidity: 80%, time: 6.5 hours) was carried out with a gas corrosion tester (GS-UV, manufactured by Suga Testing Machine Co., Ltd.). bottom.

<< Hydrogen Sulfide Gas Test >>
A hydrogen sulfide gas test (concentration: 15 volume ppm, temperature: 40 ° C., relative humidity 80%, time: 48 hours) was carried out with a gas corrosion tester (GS-UV, manufactured by Suga Tester Co., Ltd.).

<< Salt spray test >>
A salt spray test (salt water concentration: 5% by mass, temperature: 35 ° C., time: 72 hours) was carried out with a salt water corrosion tester (SQ-800-ST, manufactured by Itabashi Rika Kogyo Co., Ltd.).

<Evaluation result>
The evaluation results of Examples 1 to 24 and Comparative Examples 1 to 22 are shown in Table 4.

As the results of Examples 1 to 24 show, the appearance protective agent containing the benzotriazole ring compound and the specific amine compound or the specific ammonium compound at the same time includes a gold plating film, a gold alloy plating film, and a silver plating film. It was confirmed that it is effective in suppressing corrosion and discoloration of the surface of the palladium plating film and the palladium alloy plating film and maintaining the appearance.
The change in the surface condition due to the treatment with the appearance protective agent could not be visually confirmed.

On the other hand, as shown by the results of Comparative Examples 1 to 22, when the benzotriazole ring compound and the specific amine compound or the specific ammonium compound are not contained at the same time, the underlying copper is corroded and the appearance is maintained. Was confirmed not to be obtained.

Since the appearance protectant of the present invention has a sufficient discoloration / corrosion prevention effect even after heating during soldering, silver (alloy), nickel (alloy) or palladium (alloy) is used as a base metal. Since it suppresses discoloration and corrosion of members (metal bodies) having an alloy) plating film, gold (alloy) plating film, or palladium (alloy) plating film on the outermost layer, it is widely used in the field of manufacturing the above members (metal bodies). Is to be done.
In particular, the appearance of the surface is particularly maintained for members (metal bodies) that require heat resistance, such as gold-plated or gold-plated coatings for connector terminals and printed circuit boards; and silver-plated coatings for LED reflectors. It is widely used to do this.

Claims (8)

Silver plating film, silver alloy plating film, gold plating film, gold alloy plating film using at least one metal selected from the group consisting of copper, copper alloy, nickel, nickel alloy, palladium, and palladium alloy as the base metal. , An appearance protective agent for maintaining the appearance of a metal body having a palladium plating film or a palladium alloy plating film on the outermost layer by suppressing discoloration and / or corrosion of the outermost layer.
A benzotriazole ring compound and an amine compound represented by the following formula (2) and / or an ammonium compound having an ammonium cation represented by the following formula (3) are contained , and the benzotriazole ring compound has the following formula ( It is represented by 1), and appearance protective agent characterized der Rukoto benzotriazole ring compound having a hydroxyl group or carboxyl group or both.

[In the formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are hydrogen atoms, hydroxyl groups, halogen atoms, carboxyl groups, alkyl groups or alkoxy groups, respectively. ]

[In formula (2), R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁶ , R ⁷ and R ⁸ may be bonded to form a ring. However, this excludes cases where all of ^{R 6} , R ⁷ and R ^{8 are hydrogen atoms.} ]

[In formula (3), R ⁹ , R ¹⁰ and R ¹¹ each represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may be substituted. Any two or more of R ⁹ , R ¹⁰ and R ¹¹ may be bonded to form a ring. However, this excludes cases where all of ^{R 9} , R ¹⁰ and R ^{11 are hydrogen atoms.} ] The benzotriazole ring compounds, hydroxycarboxylic benzotriazole, carboxymethyl benzotriazole, di-hydroxybenzotriazole, chloro hydroxybenzotriazole, carboxymethyl hydroxybenzotriazole, methyl hydroxybenzotriazole, ethyl hydroxybenzotriazole, hydroxypropyl benzotriazoles, hydroxy isopropyl benzotriazole, butyl-hydroxybenzotriazole, hydroxy isobutyl benzotriazole, hydroxypentyl benzotriazoles, hydroxy isopentyl benzotriazole, carboxy-chloro-benzotriazole, carboxymethyl methylbenzotriazole, carboxyethyl benzotriazole, carboxypropyl benzotriazole, carboxy isopropylbenzo The appearance protectant according to claim 1, which is one or more compounds selected from the group consisting of triazole, carboxybutylbenzotriazole, carboxyisobutylbenzotriazole, carboxypentylbenzotriazole and carboxyisopentylbenzotriazole. The amine compounds represented by the above formula (2) are monoethanolamine, diethanolamine, triethanolamine, propanolamine, 2-amino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, DL-1. -Amino-2-propanol, N- (2-hydroxypropyl) ethylenediamine, 2- (2-aminoethylamino) ethanol, 2- (2-aminoethoxy) ethanol, tris (hydroxymethyl) aminomethane, 3-amino- 1,2-Propanediol, DL-2-amino-1-butanol, 1-amino-2-butanol, 5-amino-1-pentanol, DL-2-amino-1-propanol, 4-amino-1- Butanol, 6-amino-1-hexanol, 2-amino-1,3-propanediol, N- (3-aminopropyl) diethanolamine, 3-amino-1-butanol, N-butyldiethanolamine, 2- (butylamino) Ethanol, 2- (tert-butylamino) ethanol, N-tert-butyldiethanolamine, N, N'-bis (2-hydroxyethyl) ethylenediamine, 3-diethylamino-1-propanol, 2- (dimethylamino) ethanol, 1 -Dimethylamino-1-propanol, diisopropanolamine, 2- (diisopropylamino) ethanol, 2- (dimethylamino) -2-methyl-1-propanol, 4-dimethylamino-1-butanol, 6-dimethylamino-1 -Hexanol, 3- (diethylamino) -1,2-propanediol, 3-dimethylamino-2,2-dimethyl-1-propanol, 3- (dimethylamino) -1,2-propanediol, 4-diethylamino-2 -Butin-1-ol, 2-[[2- (dimethylamino) ethyl] methylamino] ethanol, 5-diethylamino-1-pentanol, 2- (ethylamino) ethanol, N-ethyldiethanolamine, 4-ethylamino -1-butanol, N- (3-hydroxypropyl) ethylenediamine, 1,3-diamino-2-propanol, 2-[(hydroxymethyl) amino] ethanol, 2- (isopropylamino) ethanol, 3- (isopropylamino) Propanol, 4- (isopropylamino) butanol, 5- (isopropylamino) pentanol, N-lauryldiethanolamine, 2- (methylamino) ethanol, N-me Tyrdiethanolamine, 3-methylamino-1,2-propanediol, stearyldiethanolamine, DL-valinol, bis (2-isopropoxyethyl) amine, N- (tert-butoxycarbonyl) -2,2-dimethyl-1,3 -Propanediamine, 1-aminodecane, diamilamine, 1- (2-hydroxyethyl) piperazine, N, N-dimethyl-1,3-propanediamine, N-methyl-1,3-diaminopropane, triisopropanolamine, N- (2-Aminoethyl) piperazine, tropin, 3-amino-1-phenylbutane, 4-phenylbutylamine, N- (3-aminopropyl) -N-methylaniline, 1-aminoindane, 2-aminoindane, N- Allylbenzylamine, 1-adamantanamine, 3-amino-3-phenyl-1-propanol, 4-tert-butylcyclohexylamine, N-isopropylbenzylamine, 3-benzyloxazolidine, 3-benzylamino-1-propanol, 2 , 2'-bipiperidin, 4-sec-butylcyclohexylamine, 4-butylcyclohexylamine, 3,3'-bipiperidin, N-benzyl-1,3-propanediamine, cumylamine, N, N-diethylcyclohexylamine, diisoamyl Amine, dicyclohexylamine, 1- (2-dimethylaminoethyl) -4-methylpiperazin, N- (3-aminopropyl) morpholin, N- (2-hydroxyethyl) morpholin, morpholin, diethylenetriamine, triethylenetetramine, tetraethylene Pentamine, pentaethylenehexamine, 1,3-bis (aminomethyl) cyclohexane, polyethyleneimine, arginine, glucamine, N-methyl-D-glucamine, N, N, N', N'-tetrakis (2-hydroxyethyl) The appearance protectant according to claim 1 or 2, which is one or more compounds selected from the group consisting of ethylenediamine and N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine. The counter anion of the ammonium cation represented by the above formula (3) is sulfate ion, sulfite ion, nitrate ion, nitrite ion, phosphate ion, phosphite ion, phosphonate ion, fluoride ion, chloride ion, Bromide ion, iodide ion, hypochlorite ion, chlorite ion, chlorate ion, perchlorate ion, hypobromine acid ion, bromine acid ion, bromine ion, perbromate ion, hypoiodide Claim 1 which is one or more anions selected from the group consisting of acid ion, subiodate ion, iodate ion, perioitate ion, metaborate ion, carbonate ion, hydroxide ion and organic carboxylic acid ion. The appearance protective agent according to any one of claims 3. The base metals are pure copper, beryllium copper, brass, phosphorus bronze, copper-iron alloy, Corson alloy, nickel plating film, nickel phosphorus plating film, 42 alloy, palladium plating film, palladium phosphorus plating film, palladium nickel plating film, palladium cobalt. The appearance protective agent according to any one of claims 1 to 4, which is at least one base metal selected from the group consisting of a plating film and a palladium-silver plating film. The outermost layer is a silver plating film, a silver-palladium alloy plating film, a gold plating film, a gold cobalt alloy plating film, a gold nickel alloy plating film, a gold silver alloy plating film, a gold tin alloy film, a palladium plating film, and a palladium cobalt alloy plating film. Or, the appearance protective agent according to any one of claims 1 to 5, which is a palladium-nickel alloy plating film. The appearance protective agent according to any one of claims 1 to 6, wherein the benzotriazole ring compound is a benzotriazole ring compound having a carboxyl group. Silver plating film, silver alloy plating film, gold plating film, gold alloy plating film using at least one metal selected from the group consisting of copper, copper alloy, nickel, nickel alloy, palladium, and palladium alloy as the base metal. , The surface of the metal body having the palladium plating film or the palladium alloy plating film as the outermost layer is treated with the appearance protective agent according to any one of claims 1 to 7, and the outermost layer is treated with the appearance protective agent. A method for treating a metal body, which comprises suppressing discoloration and / or corrosion to maintain an appearance.