JP5036216B2 - Metal surface treatment agent and use thereof - Google Patents

Description

  The present invention relates to a surface treatment agent used when soldering an electronic component or the like to the surface of a metal conductive portion constituting a circuit portion of a printed wiring board, and the use thereof.

Recently, surface mounting with improved mounting density has been widely adopted as a method for mounting printed wiring boards. Such surface mounting methods can be classified into double-sided surface mounting in which chip components are joined by cream solder, mixed mounting in which surface mounting by chip solder cream soldering and through-hole mounting of discrete components are combined. In any mounting method, since the printed wiring board is soldered a plurality of times, it is exposed to a high temperature each time and receives a severe thermal history.
As a result, formation of an oxide film is promoted by heating the metal surface such as copper, copper alloy or silver of the metal conductive portion constituting the circuit portion of the printed wiring board. The sticking property cannot be kept good.

  In order to protect the metal conductive part of such a printed wiring board from air oxidation, a surface treatment method for forming a chemical conversion film on the surface of the conductive part using a rust inhibitor containing various imidazole compounds as active ingredients Has been proposed (for example, Patent Documents 1 to 4).

  Incidentally, tin-lead alloy eutectic solder has been widely used in the past for joining electronic components to printed wiring boards and the like, but in recent years, the lead contained in the solder alloy has been harmful to the human body. There is concern and there is a need to use solder that does not contain lead. For this purpose, various lead-free solders have been studied. For example, lead-free solders having a metal such as silver, zinc, bismuth, indium, antimony and copper as a base metal have been proposed.

The former eutectic solder is excellent in wettability with respect to the surface of the metal and has high reliability because it is firmly bonded to the metal. On the other hand, the lead-free solder of the latter is inferior in wettability to the surface of the metal compared to eutectic solder, so the solderability is poor and joint defects such as voids are likely to occur. There was a difficulty that it was weak.
Therefore, when using lead-free solder, it is necessary to select a solder alloy with better solderability and a flux suitable for lead-free solder, but for surface treatment agents used to prevent oxidation of metal surfaces. However, there is a demand for a function that improves the wettability of lead-free solder and improves the solderability.

Japanese Patent Publication No.46-17046 JP-A-4-206681 Japanese Patent Laid-Open No. 5-25407 Japanese Patent Laid-Open No. 5-186888

The present invention has been made in view of such circumstances, and when soldering an electronic component or the like to the surface of a metal conductive portion constituting a circuit portion of a printed wiring board, the solder of the surface of the conductive portion is not soldered. It is an object of the present invention to provide a metal surface treatment agent having good wettability.
In addition, by contacting the surface treatment agent with the surface of the metal conductive portion, a printed wiring board having a chemical conversion film formed on the surface of the metal conductive portion, and the surface treatment agent on the surface of the metal conductive portion It is an object of the present invention to provide a method of manufacturing a printed wiring board in which a chemical conversion film is formed on the surface of a metal conductive portion by contacting with a lead and then soldered using lead-free solder.

As a result of intensive studies in order to solve the above problems, the present inventors have obtained a metal surface treatment agent characterized by being an aqueous solution containing an imidazole compound (excluding imidazole) and gluconic acid, and As a result, it was found that the intended purpose was achieved, and the present invention was completed.

Moreover, 2nd invention contains imidazole compound (however, except imidazole) in the ratio of 0.01-10 weight% in 1st invention, and contains gluconic acid in the ratio of 0.01-50 weight%. It is a metal surface treatment agent characterized by being an aqueous solution .
According to a third invention, in the first invention or the second invention, a chemical conversion film is formed on the surface of the metal conductive portion by bringing a metal surface treatment agent into contact with the surface of the metal conductive portion. It is the printed wiring board characterized.
According to a fourth invention, in the first invention or the second invention, after forming a chemical conversion film on the surface of the metal conductive portion by bringing a metal surface treatment agent into contact with the surface of the metal conductive portion, A printed wiring board manufacturing method characterized by performing soldering using lead-free solder.

The metal surface treatment agent of the present invention uses a combination of an imidazole compound and gluconic acid so that when an electronic component or the like is soldered to the surface of a metal conductive portion constituting a circuit portion of a printed wiring board, the conductive surface treatment agent is used. It is possible to form a chemical conversion film that improves the wettability of lead-free solder to the surface of the part. When the printed wiring board of the present invention is used, and according to the method of manufacturing a printed wiring board of the present invention, the joining of the metal conductive portion and the electronic component can be ensured by soldering using lead-free solder. .

Hereinafter, the present invention will be described in detail.
The surface treating agent of the present invention is a water-soluble liquid containing an imidazole compound and gluconic acid . The imidazole compound used in the practice of the present invention is not limited except that imidazole is excluded . For example, imidazole compounds represented by the following general formulas (I) to (VIII) represented by the following chemical formulas 1 to 8 are preferably used. Moreover, it is also possible to use these imidazole compounds in combination of two or more.

（式中、Ｒ_１は水素原子または、炭素数が１〜２５であって置換基を有してもよい直鎖状または分岐鎖状のアルキル基もしくはアルケニル基を表す。Ｒ_２およびＲ_３は、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。但し、Ｒ _１ 、Ｒ _２ およびＲ _３ が同時に水素原子である場合を除く。）

(Wherein R ₁ represents a hydrogen atom or a linear or branched alkyl group or alkenyl group having 1 to 25 carbon atoms and optionally having a substituent. R ₂ and R ₃ are Represents a hydrogen atom, a halogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, except when R ₁ , R ₂ and R ₃ are hydrogen atoms at the same time.

（式中、Ｒ_１は水素原子または、炭素数が１〜２５であって置換基を有してもよい直鎖状または分岐鎖状のアルキル基もしくはアルケニル基を表す。Ｒ_２およびＲ_３は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。）

(Wherein R ₁ represents a hydrogen atom or a linear or branched alkyl group or alkenyl group having 1 to 25 carbon atoms and optionally having a substituent. R ₂ and R ₃ are The same or different and represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms.)

（式中、Ｒ_１は水素原子、ハロゲン原子または炭素数が１〜１７である直鎖状もしくは分岐鎖状のアルキル基を表す。Ｒ_２、Ｒ_３、Ｒ_４およびＲ_５は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。）

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 17 carbon atoms. R ₂ , R ₃ , R ₄ and R ₅ are the same or different. Represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms.)

（式中、Ｒ_１は水素原子、ハロゲン原子または炭素数が１〜１７である直鎖状もしくは分岐鎖状のアルキル基を表す。Ｒ_２、Ｒ_３、Ｒ_４およびＲ_５は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。）

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 17 carbon atoms. R ₂ , R ₃ , R ₄ and R ₅ are the same or different. Represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms.)

（式中、Ｒ_１は水素原子、ハロゲン原子または炭素数が１〜１７である直鎖状もしくは分岐鎖状のアルキル基を表す。Ｒ_２、Ｒ_３、Ｒ_４およびＲ_５は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。）

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 17 carbon atoms. R ₂ , R ₃ , R ₄ and R ₅ are the same or different. Represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms.)

（式中、Ｒ_１、Ｒ_２、Ｒ_３、およびＲ_４は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。ｎは０〜６の整数を表す。）

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are the same or different and each represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms. N Represents an integer of 0 to 6.)

（式中、Ｒ_１、Ｒ_２、Ｒ_３、およびＲ_４は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。ｎは０〜６の整数を表す。）

(Wherein R ₁ , R ₂ , R ₃ , and R ₄ are the same or different and each represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms. N Represents an integer of 0 to 6.)

（式中、Ｒ_１およびＲ_２は同一または異なって、水素原子、ハロゲン原子または炭素数が１〜８である直鎖状もしくは分岐鎖状のアルキル基を表す。ｎは０〜６の整数を表す。）

(In the formula, R ₁ and R ₂ are the same or different and each represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 8 carbon atoms. N represents an integer of 0 to 6. To express.)

As an imidazole compound represented by the general formula (I) of Chemical Formula 1 ,
2 -methylimidazole,
2-ethylimidazole,
2-propylimidazole,
2-isopropylimidazole,
2-butylimidazole,
2-t-butylimidazole,
2-pentylimidazole,
2-hexylimidazole,
2-heptylimidazole,
2- (1-ethylpentyl) imidazole,
2-octylimidazole,
2-nonylimidazole,
2-decylimidazole,
2-undecylimidazole,
2-dodecylimidazole,
2-tridecylimidazole,
2-tetradecylimidazole,
2-pentadecylimidazole,
2-hexadecylimidazole,
2-heptadecylimidazole,
2-octadecylimidazole,
2-nonadecylimidazole,
2-icosanylimidazole,
2-henicosanylimidazole,
2-docosanylimidazole,
2-tricosanylimidazole,
2-tetracosanylimidazole,
2-pentacosanylimidazole,
2- (1-methylpentyl) imidazole,
2- (1-ethylpentyl) imidazole,
2- (1-heptyldecyl) imidazole,
2- (5-hexenyl) imidazole,
2- (9-octenyl) imidazole,
2- (8-heptadecenyl) imidazole,
2- (4-chlorobutyl) imidazole,
2- (9-hydroxynonyl) imidazole,
2-ethyl-4-methylimidazole,
2-undecyl-4-methylimidazole,
2-heptadecyl-4-methylimidazole,
4-methylimidazole,
4-isopropylimidazole,
4-octylimidazole,
2,4,5-trimethylimidazole,
4,5-dimethyl-2-octylimidazole,
2-undecyl-4-methyl-5-bromoimidazole,
Examples include alkyl imidazole compounds such as 4,5-dichloro-2-ethylimidazole.

As an imidazole compound represented by the general formula (II) of Chemical Formula 2,
Benzimidazole,
2-methylbenzimidazole,
2-ethylbenzimidazole,
2-propylbenzimidazole,
2-isopropylbenzimidazole,
2-butylbenzimidazole,
2-t-butylbenzimidazole,
2-pentylbenzimidazole,
2-hexylbenzimidazole,
2- (1-methylpentyl) benzimidazole,
2-heptylbenzimidazole,
2- (1-ethylpentyl) benzimidazole,
2-octylbenzimidazole,
2- (2,4,4-trimethylpentyl) benzimidazole,
2-nonylbenzimidazole,
2-decylbenzimidazole,
2-undecylbenzimidazole,
2-dodecylbenzimidazole,
2-tridecylbenzimidazole,
2-tetradecylbenzimidazole,
2-pentadecylbenzimidazole,
2-hexadecylbenzimidazole,
2-heptadecylbenzimidazole,
2- (1-heptyldecyl) benzimidazole,
2-octadecylbenzimidazole,
2-nonadecylbenzimidazole,
2-icosanylbenzimidazole,
2-henicosanylbenzimidazole,
2-docosanylbenzimidazole,
2-tricosanylbenzimidazole,
2-tetracosanylbenzimidazole,
2-pentacosanylbenzimidazole,
2- (8-octylhexadecyl) benzimidazole,
2- (9-octenyl) benzimidazole,
2- (8-heptadecenyl) benzimidazole,
2- (4-chlorobutyl) benzimidazole,
2- (9-hydroxynonyl) benzimidazole,
2-hexyl-5-methylbenzimidazole,
2-heptyl-5,6-dimethylbenzimidazole,
2-octyl-5-chlorobenzimidazole,
2-ethyl-5-octyl-6-bromobenzimidazole,
2-pentyl-5,6-dichlorobenzimidazole,
4-fluorobenzimidazole,
Examples thereof include alkylbenzimidazole compounds such as 2-pentyl-5-iodobenzimidazole.

As the imidazole compound represented by the general formula (III) of Chemical Formula 3,
2,4-diphenylimidazole,
2- (2-methylphenyl) -4-phenylimidazole,
2- (3-octylphenyl) -4-phenylimidazole,
2- (2,4-dimethylphenyl) -4-phenylimidazole,
2-phenyl-4- (4-hexylphenyl) imidazole,
2-phenyl-4- (2-methyl-5-butylphenyl) imidazole,
2,4-diphenyl-5-methylimidazole,
2,4-diphenyl-5-hexylimidazole,
2- (2,4-diethyl) -4- (3-propyl-5-octyl) -5-isobutylimidazole,
2- (2-chlorophenyl) -4-phenylimidazole,
2- (3-chlorophenyl) -4-phenylimidazole,
2- (4-chlorophenyl) -4-phenylimidazole,
2- (2-bromophenyl) -4-phenylimidazole,
2- (3-bromophenyl) -4-phenylimidazole,
2- (4-bromophenyl) -4-phenylimidazole,
2- (2-iodophenyl) -4-phenylimidazole,
2- (3-iodophenyl) -4-phenylimidazole,
2- (4-iodophenyl) -4-phenylimidazole,
2- (2-fluorophenyl) -4-phenylimidazole,
2- (3-fluorophenyl) -4-phenylimidazole,
2- (4-fluorophenyl) -4-phenylimidazole,
2- (2,3-dichlorophenyl) -4-phenylimidazole,
2- (2,4-dichlorophenyl) -4-phenylimidazole,
2- (2,5-dichlorophenyl) -4-phenylimidazole,
2- (2,6-dichlorophenyl) -4-phenylimidazole,
2- (3,4-dichlorophenyl) -4-phenylimidazole,
2- (3,5-dichlorophenyl) -4-phenylimidazole,
2- (2,4-dibromophenyl) -4-phenylimidazole,
2- (2-methyl-4-chlorophenyl) -4-phenylimidazole,
2- (3-bromo-5-octylphenyl) -4-phenylimidazole,
2- (2-chlorophenyl) -4-phenyl-5-methylimidazole,
2- (3-chlorophenyl) -4-phenyl-5-methylimidazole,
2- (4-chlorophenyl) -4-phenyl-5-methylimidazole,
2- (2-bromophenyl) -4-phenyl-5-methylimidazole,
2- (3-bromophenyl) -4-phenyl-5-methylimidazole,
2- (4-bromophenyl) -4-phenyl-5-methylimidazole,
2- (2-iodophenyl) -4-phenyl-5-methylimidazole,
2- (3-iodophenyl) -4-phenyl-5-methylimidazole,
2- (4-iodophenyl) -4-phenyl-5-methylimidazole,
2- (2-fluorophenyl) -4-phenyl-5-methylimidazole,
2- (3-fluorophenyl) -4-phenyl-5-methylimidazole,
2- (4-fluorophenyl) -4-phenyl-5-methylimidazole,
2- (2,3-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (2,4-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (2,5-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (2,6-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (3,4-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (3,5-dichlorophenyl) -4-phenyl-5-methylimidazole,
2- (2,4-dichlorophenyl) -4-phenyl-5-ethylimidazole,
2- (2,3-dichlorophenyl) -4-phenyl-5-decylimidazole,
2- (3,4-dichlorophenyl) -4-phenyl-5-heptadecylimidazole,
2- (2,4-dibromophenyl) -4-phenyl-5-isopropylimidazole,
2- (2-heptyl-4-chlorophenyl) -4-phenyl-5-isobutylimidazole,
2-phenyl-4- (2-chlorophenyl) imidazole,
2-phenyl-4- (3-chlorophenyl) imidazole,
2-phenyl-4- (4-chlorophenyl) imidazole,
2-phenyl-4- (2-bromophenyl) imidazole,
2-phenyl-4- (3-bromophenyl) imidazole,
2-phenyl-4- (4-bromophenyl) imidazole,
2-phenyl-4- (2-iodophenyl) imidazole,
2-phenyl-4- (3-iodophenyl) imidazole,
2-phenyl-4- (4-iodophenyl) imidazole,
2-phenyl-4- (2-fluorophenyl) imidazole,
2-phenyl-4- (3-fluorophenyl) imidazole,
2-phenyl-4- (4-fluorophenyl) imidazole,
2-phenyl-4- (2,3-dichlorophenyl) imidazole,
2-phenyl-4- (2,4-dichlorophenyl) imidazole,
2-phenyl-4- (2,5-dichlorophenyl) imidazole,
2-phenyl-4- (2,6-dichlorophenyl) imidazole,
2-phenyl-4- (3,4-dichlorophenyl) imidazole,
2-phenyl-4- (3,5-dichlorophenyl) imidazole,
2-phenyl-4- (2,3-dibromophenyl) imidazole,
2-phenyl-4- (2-propyl-3-chlorophenyl) imidazole,
2-phenyl-4- (3-bromo-4-heptylphenyl) imidazole,
2-phenyl-4- (2-chlorophenyl) -5-methylimidazole,
2-phenyl-4- (3-chlorophenyl) -5-methylimidazole,
2-phenyl-4- (4-chlorophenyl) -5-methylimidazole,
2-phenyl-4- (2-bromophenyl) -5-methylimidazole,
2-phenyl-4- (3-bromophenyl) -5-methylimidazole,
2-phenyl-4- (4-bromophenyl) -5-methylimidazole,
2-phenyl-4- (2-iodophenyl) -5-methylimidazole,
2-phenyl-4- (3-iodophenyl) -5-methylimidazole,
2-phenyl-4- (4-iodophenyl) -5-methylimidazole,
2-phenyl-4- (2-fluorophenyl) -5-methylimidazole,
2-phenyl-4- (3-fluorophenyl) -5-methylimidazole,
2-phenyl-4- (4-fluorophenyl) -5-methylimidazole,
2-phenyl-4- (2,3-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (2,4-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (2,5-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (2,6-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (3,4-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (3,5-dichlorophenyl) -5-methylimidazole,
2-phenyl-4- (2,3-dichlorophenyl) -5-propylimidazole,
2-phenyl-4- (2,4-dichlorophenyl) -5-undecylimidazole,
2-phenyl-4- (2,4-dibromophenyl) -5- (1-methylbutyl) imidazole,
2-phenyl-4- (2-hexyl-4-iodophenyl) -5-propylimidazole,
2,4-bis (4-chlorophenyl) imidazole 2- (2,4-dichlorophenyl) -4- (3,4-dichlorophenyl) -5-methylimidazole,
2- (2-bromo-4-octylphenyl) -4- (2-methyl-4-iodophenyl) -5-octylimidazole,
2,4-diphenyl-5-fluoroimidazole,
2,4-diphenyl-5-chloroimidazole,
2,4-diphenyl-5-bromoimidazole,
2,4-diphenyl-5-iodoimidazole,
2- (4-methylphenyl) -4-phenyl-5-chloroimidazole,
2- (4-chlorophenyl) -4-phenyl-5-bromoimidazole,
Examples include 2-phenyl-4- (2-chlorophenyl) -5-iodoimidazole.

As an imidazole compound represented by the general formula (IV) of Chemical Formula 4,
2-phenyl-4- (1-naphthyl) imidazole,
2-phenyl-4- (2-naphthyl) imidazole,
2- (4-methylphenyl) -4- (4-chloro-6-butyl-1-naphthyl) imidazole,
2- (2-octyl-4-ethylphenyl) -4- (5-chloro-7-heptyl-1-naphthyl) imidazole,
2- (2,4-dichlorophenyl) -4- (2-isobutyl-6-bromo-2-naphthyl) imidazole,
2-phenyl-4- (1-naphthyl) -5-methylimidazole,
2- (4-iodophenyl) -4- (5,6-dimethyl-1-naphthyl) -5-decylimidazole,
2-phenyl-4- (2-naphthyl) -5-methylimidazole,
2- (2,3-difluorophenyl) -4- (7-octyl-2-naphthyl) -5-heptadecylimidazole,
2-phenyl-4- (1-naphthyl) -5-fluoroimidazole,
2-phenyl-4- (1-naphthyl) -5-chloroimidazole,
2-phenyl-4- (1-naphthyl) -5-bromoimidazole,
2-phenyl-4- (1-naphthyl) -5-iodoimidazole,
2-phenyl-4- (2-naphthyl) -5-fluoroimidazole,
2-phenyl-4- (2-naphthyl) -5-chloroimidazole,
2-phenyl-4- (2-naphthyl) -5-bromoimidazole,
2-phenyl-4- (2-naphthyl) -5-iodoimidazole,
Examples include 2- (4-methylphenyl) -4- (5-chloro-1-naphthyl) -5-chloroimidazole.

As an imidazole compound represented by the general formula (V) of Chemical Formula 5,
2- (1-naphthyl) -4-phenylimidazole,
2- (2-naphthyl) -4-phenylimidazole,
2- (2-methyl-5-chloro-1-naphthyl) -4- (4-hexylphenyl) imidazole,
2- (2-isobutyl-5-iodo-2-naphthyl) -4- (2-pentyl-5-fluorophenyl) imidazole,
2- (1-naphthyl) -4-phenyl-5-methylimidazole,
2- (3,6-dichloro-2-naphthyl) -4- (2-isopropyl-5-fluorophenyl-5-decylimidazole),
2- (6-propyl-7-iodo-1-naphthyl) -4- (3-hexyl-6-bromophenyl) -5-heptadecylimidazole,
2- (1-naphthyl) -4-phenyl-5-fluoroimidazole,
2- (1-naphthyl) -4-phenyl-5-chloroimidazole,
2- (1-naphthyl) -4-phenyl-5-bromoimidazole,
2- (1-naphthyl) -4-phenyl-5-iodoimidazole,
2- (2-naphthyl) -4-phenyl-5-fluoroimidazole,
2- (2-naphthyl) -4-phenyl-5-chloroimidazole,
2- (2-naphthyl) -4-phenyl-5-bromoimidazole,
2- (2-naphthyl) -4-phenyl-5-iodoimidazole,
Examples include 2- (4-chloro-2-naphthyl) -4- (2-hexylphenyl) -5-chloroimidazole.

As an imidazole compound represented by the general formula (VI) of Chemical Formula 6,
2-phenylbenzimidazole,
2- (4-methylphenyl) benzimidazole,
2- (2,4-dichlorophenyl) benzimidazole,
2- (2-hexylphenyl) -5-chlorobenzimidazole,
2- (phenylmethyl) benzimidazole,
2- (4-ethylphenylmethyl) benzimidazole,
2- (4-chlorophenylmethyl) benzimidazole,
2- (2,4-dichlorophenylmethyl) benzimidazole,
2- (3,4-dichlorophenylmethyl) benzimidazole,
2- (4-bromophenylmethyl) -5-ethylbenzimidazole,
2- (3-iodophenylmethyl) -4-chlorobenzimidazole,
2- (2-phenylethyl) benzimidazole,
2- [2- (3-isopropylphenyl) ethyl] benzimidazole,
2- [2- (4-chlorophenyl) ethyl] benzimidazole,
2- [2- (4-chlorophenyl) ethyl] -4,5-dimethylbenzimidazole,
2- (3-phenylpropyl) benzimidazole,
2- [3- (4-t-butylphenyl) propyl] benzimidazole,
2- [3- (2-chlorophenyl) propyl] benzimidazole,
2- [3- (4-bromophenyl) propyl] -5-butylbenzimidazole,
2- (4-phenylbutyl) benzimidazole,
2- [4- (4-chlorophenyl) butyl] benzimidazole,
2- [4- (2,4-dichlorophenyl) butyl] -4,7-dichlorobenzimidazole,
2- (5-phenylpentyl) benzimidazole,
2- [5- (2-octylphenyl) pentyl] benzimidazole,
2- [5- (3,4-dichlorophenyl) pentyl] -5-heptylbenzimidazole,
2- (6-phenylhexyl) benzimidazole,
2- [6- (3-hexylphenyl) hexyl] benzimidazole,
Examples include 2- [6- (2-ethyl-3-fluorophenyl) hexyl] 4-butyl-5-octylbenzimidazole.

As an imidazole compound represented by the general formula (VII) of Chemical Formula 7,
2- (1-naphthyl) benzimidazole,
2- (1-naphthyl) -4-methylbenzimidazole,
2- (2-naphthyl) benzimidazole,
2- (1-chloro-2-naphthyl) -5,6-dichlorobenzimidazole,
2- (1-naphthylmethyl) benzimidazole,
2- (4,6-dimethyl-1-naphthylmethyl) -5-ethylbenzimidazole,
2- (7-bromo 1-naphthylmethyl) -5-bromobenzimidazole,
2- (2-naphthylmethyl) benzimidazole,
2- (4-isopropyl-2-naphthylmethyl) -5-t-butylbenzimidazole,
2- [2- (1-naphthyl) ethyl] benzimidazole,
2- [2- (5-pentyl-1-naphthyl) ethyl] -5-chlorobenzimidazole,
2- [2- (2-naphthyl) ethyl] benzimidazole,
2- [2- (6-heptyl-2-naphthyl) ethyl] -4-methyl-5-hexylbenzimidazole,
2- [3- (1-naphthyl) propyl] benzimidazole,
2- [3- (4-iodo-1-naphthyl) propyl] -5,6-dibromobenzimidazole,
2- [3- (2-naphthyl) propyl] benzimidazole,
2- [3- (8-isopropyl-2-naphthyl) propyl] -5- (2-methylpentyl) benzimidazole,
2- [4- (1-naphthyl) butyl] benzimidazole,
2- [4- (5-fluoro-1-naphthyl) butyl] -4- (2-propylbutyl) benzimidazole,
2- [4- (2-naphthyl) butyl] benzimidazole,
2- [4- (7-octyl-2-naphthyl) butyl] -4,6-diethylbenzimidazole,
2- [5- (1-naphthyl) pentyl] benzimidazole,
2- [5- (6-pentyl-7-fluoro-1-naphthyl) pentyl] -4,7-dipropylbenzimidazole,
2- [5- (2-naphthyl) pentyl] benzimidazole,
2- [5- (6,7-dimethyl-2-naphthyl) pentyl] -5,6-dichlorobenzimidazole,
2- [6- (6,7-diethyl-1-naphthyl) hexyl] -5-octylbenzimidazole,
2- [6- (2-naphthyl) hexyl] benzimidazole,
Examples include 2- [6- (7-ethyl-8-bromo-2-naphthyl) hexyl] -4-hexyl-6-fluorobenzimidazole.

As the imidazole compound represented by the general formula (VIII) of Chemical Formula 8,
2-cyclohexylbenzimidazole,
2-cyclohexyl-5,6-dimethylbenzimidazole,
2-cyclohexyl-5-chlorobenzimidazole,
2-cyclohexyl-4-isopropylbenzimidazole 2- (cyclohexylmethyl) benzimidazole,
2- (cyclohexylmethyl) -5-ethylbenzimidazole,
2- (cyclohexylmethyl) -5-bromobenzimidazole,
2- (2-cyclohexylethyl) benzimidazole,
2- (2-cyclohexylethyl) -5-chloro-6-methylbenzimidazole,
2- (3-cyclohexylpropyl) benzimidazole,
2- (3-cyclohexylpropyl) -5-butylbenzimidazole,
2- (3-cyclohexylpropyl) -4,7-dimethylbenzimidazole,
2- (4-cyclohexylbutyl) benzimidazole,
2- (4-cyclohexylbutyl) -5-iodobenzimidazole,
2- (4-cyclohexylbutyl) -4-chloro-5-ethylbenzimidazole,
2- (4-cyclohexylbutyl) -5-octylbenzimidazole,
2- (5-cyclohexylpentyl) benzimidazole,
2- (5-cyclohexylpentyl) -5-hexylbenzimidazole,
2- (5-cyclohexylpentyl) -5,6-dibromobenzimidazole,
2- (6-cyclohexylhexyl) benzimidazole,
2- (6-cyclohexylhexyl) -5-heptylbenzimidazole,
Examples include 2- (6-cyclohexylhexyl) -4-chloro-5- (2-propylbutyl) benzimidazole.

  In the practice of the present invention, these imidazole compounds may be contained in the surface treatment agent in a proportion of 0.01 to 10% by weight, preferably in a proportion of 0.1 to 5% by weight. When the content ratio of the imidazole compound is less than 0.01% by weight, the film thickness of the chemical conversion film formed on the metal surface becomes thin, and oxidation of the metal surface cannot be sufficiently prevented. Moreover, when the content rate of an imidazole compound is made more than 10 weight%, control of the surface treatment for obtaining the desired film thickness suitable for soldering conditions becomes difficult.

Gluconic acid used in the practice of the present invention, that having a structure represented by the following formula 9.
The gluconic acid may be contained in the surface treatment agent in a proportion of 0.01 to 50% by weight, preferably 0.1 to 30% by weight. When the content ratio of gluconic acid is less than 0.01% by weight, the effect of improving the solder wettability is not sufficient, and even when it exceeds 50% by weight, the effect of improving the solder wettability is increased. I can't expect it.

Gluconic acid is known to have a function of coordinating to metal (chelating ability), but when an imidazole compound forms a complex on the metal surface and aggregates and deposits by intermolecular bonding to form a chemical conversion film In addition, it is thought that some sort of action is exerted.

In the practice of the present invention, a known organic acid, inorganic acid or organic solvent can be used as a solubilizing agent when the imidazole compound is made into an aqueous solution.
Typical organic acids used in this case include formic acid, acetic acid, propionic acid, butyric acid, glyoxylic acid, pyruvic acid, acetoacetic acid, levulinic acid, heptanoic acid, caprylic acid, capric acid, lauric acid, glycolic acid, Glyceric acid, lactic acid, acrylic acid, benzoic acid, paranitrobenzoic acid, paratoluenesulfonic acid, methanesulfonic acid, salicylic acid, picric acid, oxalic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, adipic acid, etc. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid and the like.

  Moreover, you may use the carboxylic acid compound shown by the general formula of Chemical formula 10 as an organic acid.

（式中、Ｒ_１は炭素数が１〜４である直鎖状または分岐鎖状のアルキル基、Ｒ_２は水素原子またはメチル基を表す。ｍは０〜３の整数を表し、ｎは１または２を表す。）

(In the formula, R ₁ represents a linear or branched alkyl group having 1 to 4 carbon atoms, R ₂ represents a hydrogen atom or a methyl group, m represents an integer of 0 to 3, and n represents 1; Or represents 2.)

  These acid compounds can be used alone or in combination, and may be contained in the surface treatment agent in a proportion of 0.1 to 50% by weight, preferably 1 to 30% by weight. If the content of the acid compound is less than 0.1% by weight, the imidazole compound cannot be sufficiently solubilized, and if it exceeds 50% by weight, an increase in the solubilizing effect of the imidazole compound can be expected. However, the drug cost of the acid compound only increases.

  Examples of the organic solvent include lower alcohols such as methanol, ethanol and isopropyl alcohol which are freely mixed with water, acetone, N, N-dimethylformamide, ethylene glycol and the like.

To the surface treatment agent of the present invention, a copper compound can be added in order to increase the formation rate of the chemical conversion film on the surface of the metal conductive portion, and in order to further improve the heat resistance of the formed chemical conversion film, zinc is added. A compound may be added.
Representative examples of the copper compound include copper acetate, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, copper iodide, copper hydroxide, copper phosphate, copper sulfate. Typical examples of the zinc compound include zinc oxide, zinc chloride, zinc bromide, zinc iodide, zinc formate, zinc acetate, zinc oxalate, zinc lactate, zinc citrate, sulfuric acid. Zinc, zinc nitrate, zinc phosphate and the like can be mentioned, and any of them may be contained in the surface treatment agent in a proportion of 0.01 to 10% by weight, preferably 0.02 to 5% by weight.

  When using these copper compounds and zinc compounds, the pH of the surface treatment agent is adjusted by adding a substance having a buffering action such as ammonia or amines such as monoethanolamine, diethanolamine, and triethanolamine to the surface treatment agent. Is preferably stabilized.

  In the surface treatment agent of the present invention, in order to further improve the formation rate of the chemical conversion film and the heat resistance of the film, the halogen compound is added in an amount of 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight. It can be made to contain in the ratio. Examples of the halogen compound include sodium fluoride, potassium fluoride, ammonium fluoride, sodium chloride, potassium chloride, ammonium chloride, sodium bromide, potassium bromide, ammonium bromide, sodium iodide, potassium iodide, ammonium iodide. Etc.

  As conditions when processing the surface of the metal conductive part of a printed wiring board using the surface treating agent of this invention, the liquid temperature of a surface treating agent shall be 10-70 degreeC, and contact time shall be 1 second-10 minutes. It is preferable. Examples of the contact method include dipping, spraying, and application methods.

Moreover, after performing the surface treatment of this invention, it is also possible to form a double structure with a thermoplastic resin on a chemical conversion film, and to further improve heat resistance.
That is, after forming a chemical conversion film on the surface of a metal conductive part, rosin derivatives such as rosin and rosin ester, terpene resin derivatives such as terpene resin and terpene phenol resin, aromatic hydrocarbon resin and aliphatic hydrocarbon resin A thermoplastic resin excellent in heat resistance composed of a hydrocarbon resin such as the above or a mixture thereof is dissolved in a solvent such as toluene, ethyl acetate, isopropyl alcohol, and the thickness of 1 to 30 μm on the chemical conversion film by a roll coater or the like. It is sufficient to apply uniformly to form a double structure of the chemical conversion film and the thermoplastic resin.

  As a soldering method applicable to the present invention, for example, a printed wiring board is poured over a solder bath containing heated and melted liquid solder, and soldering is performed on a joint portion between the electronic component and the printed wiring board. There is a flow method or a reflow method in which paste-like cream solder is printed on a printed wiring board in advance according to the circuit pattern, electronic components are mounted there, the printed wiring board is heated to melt the solder, and soldering is performed. Can be mentioned.

  As solder suitable for the soldering of the present invention, Sn-Ag-Cu, Sn-Ag-Bi, Sn-Bi, Sn-Ag-Bi-In, Sn-Zn, Sn-Cu, etc. Although lead-free solder is mentioned, it is also possible to use eutectic solder of tin-lead alloy which has been conventionally used.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these. In addition, the raw material used by the Example and the comparative example and the evaluation test method are as follows. Commercially available reagents were used for raw materials not described.

[Imidazole compound]
2,4-diphenyl-5-methylimidazole (synthesized according to the method described in JP-A-7-243053)
2- (2,4-dichlorophenyl) -4-phenyl-5-methylimidazole (synthesized according to the method described in JP-A-2004-277386)
2-phenyl-4- (3,4-dichlorophenyl) imidazole (synthesized according to the method described in JP-A-2005-104878)
2- (1-naphthyl) -4-phenyl-5methylimidazole (synthesized according to the method described in JP-A-2006-36683)
2-phenyl-4- (2-naphthyl) imidazole (synthesized according to the method described in JP-A-2006-36683)
2- (4-Chlorophenylmethyl) benzimidazole (synthesized according to the method described in Science of Synthesis, 12 , 529 (2002))
2- (1-naphthylmethyl) benzimidazole (Biochemical Pharmacology, 36 ,
463 (1987) synthesized)

・ Gluconic acid (50% aqueous solution, reagent manufactured by Wako Pure Chemical Industries)

[Evaluation test of solderability]
As a test piece, a printed wiring board made of glass epoxy resin of 120 mm (vertical) × 150 mm (horizontal) × 1.6 mm (thickness) having 300 copper through holes with an inner diameter of 0.80 mm was used. The test piece was degreased, soft-etched and washed with water, then immersed in a surface treatment agent maintained at a predetermined liquid temperature for a predetermined time, then washed with water and dried to a thickness of about 0.10 to 0.00 on the copper surface. A 50 μm chemical conversion film was formed.
About the test piece which performed this surface treatment, the reflow heating whose peak temperature is 245 degreeC was performed 3 times using the infrared reflow apparatus (product name: MULTI-PRO-306, Vitronics company make), then, flow solder Soldering was performed using an attaching device (conveyor speed: 1.0 m / min).
The solder used is a lead-free solder (trade name: H705 “Eco Solder”, manufactured by Senju Metal Industry Co., Ltd.) having a composition of 96.5 tin-3.0 silver-0.5 copper (% by weight). The flux used for attaching is JS-E-09 (manufactured by Hiroki). The solder temperature was 245 ° C.
For the soldered test piece, the number of through holes where the solder rose to the upper land portion of the copper through hole (soldered) was measured, and the ratio (%) to the total number of through holes (300 holes) was calculated. .
The greater the solder wettability with respect to the copper surface, the more easily the molten solder penetrates into the copper through hole and rises to the upper land portion of the through hole. That is, it is determined that the higher the ratio of the number of through holes in which the solder has risen to the upper land portion with respect to the total number of through holes, the better the solder wettability with respect to copper and the better the solderability.

[Evaluation test of solder spreadability]
As a test piece, a printed wiring board made of glass epoxy resin of 50 mm (vertical) × 50 mm (horizontal) × 1.2 mm (thickness) (as a circuit pattern, a circuit part having a conductor width of 0.80 mm and a length of 20 mm made of copper foil) 10 were formed in the width direction at intervals of 1.0 mm). The test piece was degreased, soft-etched and washed with water, then immersed in a surface treatment agent maintained at a predetermined liquid temperature for a predetermined time, then washed with water and dried to a thickness of about 0.10 to 0.00 on the copper surface. A 50 μm chemical conversion film was formed.
About the test piece which performed this surface treatment, the reflow heating whose peak temperature is 245 degreeC was performed once using the infrared reflow apparatus (Product name: MULTI-PRO-306, Vitronics company make). Thereafter, cream solder was printed in the center of the copper circuit portion using a metal mask having an opening diameter of 1.2 mm and a thickness of 150 μm, and reflow heating was performed under the previous conditions to perform soldering. In addition, the used cream solder is a lead-free solder (trade name: M705-221BM5-42-11, manufactured by Senju Metal Industry Co., Ltd.) composed of 96.5 tin-3.0 silver-0.5 copper (% by weight). is there.
About the obtained test piece, the length (mm) of the solder which spread on the surface of the copper circuit part was measured.
The larger this length, the better the solder wettability and the better the solderability.

[Example 1]
Ion exchange with 2,4-diphenyl-5-methylimidazole as the imidazole compound, acetic acid and gluconic acid as the solubilizer, copper acetate as the metal salt, and ammonium iodide as the halogen compound, each with the composition shown in Table 1. After dissolving in water, the surface treatment agent was prepared by adjusting to pH 3.6 with aqueous ammonia.
Next, the test piece of the printed wiring board was immersed in a water-soluble preflux adjusted to 40 ° C. for 60 seconds, then washed with water and dried, and the solderability and solder spreadability were measured. These test results were as shown in Table 1.

[Examples 2-9, Comparative Examples 1-9]
In the same manner as in Example 1, a surface treatment agent having the composition and pH described in Table 1 was prepared, surface treatment was performed under the treatment conditions described in Table 1, and an evaluation test was performed. The test results obtained were as shown in Table 1.

Claims (4)

A metal surface treatment agent characterized by being an aqueous solution containing an imidazole compound (excluding imidazole) and gluconic acid. 2. An aqueous solution containing an imidazole compound (excluding imidazole) in a proportion of 0.01 to 10% by weight and gluconic acid in a proportion of 0.01 to 50% by weight. Metal surface treatment agent.   A printed wiring board, wherein a chemical film is formed on the surface of a metal conductive portion by bringing the metal surface treatment agent according to claim 1 or 2 into contact with the surface of the metal conductive portion.   A metal surface treatment agent according to claim 1 or 2 is brought into contact with the surface of the metal conductive portion to form a chemical conversion film on the surface of the metal conductive portion, and then soldered using lead-free solder. A method for manufacturing a printed wiring board, comprising: