Surface treatment agent for copper or copper alloy

Abstract

To provide a surface treatment agent that exhibits excellent heat resistance of a chemical conversion film formed on a copper surface and ensures good solderability during soldering.SOLUTION: A surface treatment agent for copper or a copper alloy according to the present invention contains: an imidazole compound represented by chemical formula (I) or a benzimidazole compound represented by chemical formula (II); and a triazole compound represented by chemical formula (III). The definition of each substituent in chemical formulae (I)-(III) is the same as that defined in the specification.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a surface treatment agent for use on copper or copper alloys of printed wiring boards.

Background Art

[0002] Recently, as a method for mounting printed wiring boards, surface mounting with improved mounting density has been widely adopted. Such surface mounting methods can be classified into double-sided surface mounting in which chip components are joined with cream solder, mixed mounting in which surface mounting of chip components with cream solder and through-hole mounting of discrete components are combined, and the like. In any mounting method, since the printed wiring board is soldered multiple times, it is exposed to high temperatures each time and undergoes a severe thermal history. As a result, the surface of the copper or copper alloy (hereinafter sometimes simply referred to as copper) that constitutes the circuit portion of the printed wiring board promotes the formation of an oxide film when heated, so that the solderability of the surface of the circuit portion cannot be maintained well.

[0003] In order to protect the copper circuit portions of such printed wiring boards from oxidation by air or heat, a treatment for forming a chemical conversion film on the surface of the copper circuit portions using a surface treatment agent (preflux) is widely performed. The chemical conversion film called an OSP (Organic Solderability Preservative) film formed by the surface treatment agent is required to protect the copper circuit portions without the chemical conversion film being transformed (deteriorated) even after the copper circuit portions have received a plurality of thermal histories, thereby maintaining good solderability.

[0004] On the other hand, when joining electronic components to printed wiring boards and the like, eutectic solder of a tin-lead alloy has conventionally been widely used. However, in recent years, there are concerns about the harmfulness to the human body caused by lead (Pb) contained in the solder alloy, and it is required to use lead-free solder. For this reason, various lead-free solders have been studied. For example, lead-free solders based on tin (Sn) as the base metal and added with metals such as silver (Ag), zinc (Zn), bismuth (Bi), indium (In), antimony (Sb), cobalt (Co), manganese (Mn), nickel (Ni), and copper (Cu) have been proposed.

[0005] By the way, conventional Sn-Pb eutectic solder is excellent in wettability with respect to the metal used for the joining base material, especially the surface of copper, and firmly joins to copper. Therefore, high reliability has been obtained regarding the joinability between copper members. On the other hand, lead-free solder has inferior wettability with respect to the surface of copper compared to conventional Sn-Pb eutectic solder. Therefore, the soldering property is poor, joining defects such as void generation occur, and the joining strength is also low.

[0006] Therefore, when using lead-free solder, it is required to select a solder alloy with better soldering property and a flux suitable for lead-free solder. Also, for the surface treatment agent used for preventing oxidation of the copper surface, a function of improving the wettability of lead-free solder and making the soldering property good is required. Moreover, many lead-free solders have a high melting point, and the soldering temperature becomes about 20 to 50 °C higher than that of conventional Sn-Pb eutectic solder. Therefore, it is also desired to form a chemical conversion film having excellent heat resistance on the surface treatment agent.

[0007] An imidazole compound is used as an active ingredient in such a surface treatment agent, and various studies have been conducted. For example, Patent Documents 1 and 2 propose a surface treatment agent for copper or a copper alloy containing an imidazole compound having a specific substituent.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In order to improve the performance of electronic devices, it is required to maintain good solderability of electronic components to printed wiring boards. In particular, when using lead-free solder, further improvement of surface treatment agents is required to prevent oxidation of the copper surface. Therefore, an object of the present invention is to provide a surface treatment agent that has excellent heat resistance of a chemical conversion film formed on a copper surface and can obtain good solderability when performing soldering.

MEANS FOR SOLVING THE PROBLEMS

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that by treating a printed wiring board having a copper circuit portion with a surface treatment agent containing an imidazole compound or a benzimidazole compound having a specific structure and further containing a triazole compound having a specific structure as an auxiliary agent, the above problems can be solved, and the present invention has been completed.

[0011] That is, the present invention is as follows in [1] to [6] below. 〔1〕A surface treatment agent for copper or a copper alloy, characterized by containing an imidazole compound represented by the following chemical formula (I) or a benzimidazole compound represented by the following chemical formula (II), and a triazole compound represented by the following chemical formula (III).

[0012]

CHEM.

[0013] (In formula (I), R1 is a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzyl group which may have a substituent, a naphthylmethyl group, -CH-(Ph)2, -(CH2) k-Ph, a thienyl group, a thienylmethyl group, a furyl group or a pyridyl group, where Ph represents a phenyl group which may have a substituent, and k represents an integer of 2 to 5. R2 is the same or different and represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group, provided that the case where R2 is a hydrogen atom at the same time is excluded.

[0014]

Chemical formula

[0015] (In formula (II), R3 is a linear or branched alkyl group having 1 to 18 carbon atoms, -(CH2) m -Ph, -(CH2) m -Np or a group represented by the following formula (1), Ph represents a phenyl group which may have a substituent, Np represents a naphthyl group which may have a substituent, and m represents an integer of 1 to 5.

[0016]

Chemical formula

[0017] (In formula (1), m represents an integer of 1 to 5.) R4 is the same or different and represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a nitro group or a halogen atom.)

[0018]

Chemical formula

[0019] (In formula (III), R5 and R6 are the same or different and each represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an amino group, a phenyl group which may have a substituent, a benzyl group which may have a substituent, a naphthyl group, a pyridyl group or a group represented by the following formula (2), provided that the case where both R5 and R6 are groups represented by the following formula (2) is excluded.

[0020]

Chemical formula

[0021] (In formula (2), t represents an integer of 0 to 12.) R7 is a hydrogen atom, a benzyl group or -(CH2) n -COOH, and n represents an integer of 1 to 5.)

[0022] 〔2〕The surface treatment agent for copper or a copper alloy according to 〔1〕 above, further containing a halide ion. 〔3〕The surface treatment agent for copper or a copper alloy according to 〔2〕 above, wherein the halide ion is a chloride ion. 〔4〕The surface treatment agent for copper or a copper alloy according to any one of 〔1〕 to 〔3〕 above, further containing a zinc ion. 〔5〕The surface treatment agent for copper or a copper alloy according to any one of 〔1〕 to 〔4〕 above, wherein the triazole compound represented by the chemical formula (III) is contained in a molar ratio of 0.005 to 3.0 with respect to the imidazole compound represented by the chemical formula (I) or the benzimidazole compound represented by the chemical formula (II). 〔6〕The surface treatment agent for copper or a copper alloy according to any one of 〔1〕 to 〔5〕 above, wherein the pH is 2 to 5.

Advantages of the Invention

[0023] The surface treatment agent for copper or copper alloy of the present invention can form a chemical conversion film with excellent heat resistance on the surface of copper or copper alloy constituting a circuit part of a printed wiring board, etc., and can dramatically improve the wettability of solder to the surface, and can make the solderability good.

Mode for Carrying Out the Invention

[0024] Hereinafter, the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

[0025] The surface treatment agent for copper or copper alloy of the present invention is a surface treatment agent (water-soluble preflux) containing an imidazole compound represented by formula (I) or a benzimidazole compound represented by formula (II) as an active ingredient, and containing a triazole compound represented by formula (III) as an auxiliary agent. When the surface treatment agent of the present invention adheres to copper or copper alloy, copper ions eluted from the copper surface react with the imidazole compound represented by formula (I) or the benzimidazole compound represented by formula (II), and a copper-imidazole complex is formed. Since this copper-imidazole complex is insoluble in the surface treatment agent, it deposits on the copper or copper surface to form a chemical conversion film (OSP film). By containing the triazole compound represented by formula (III) in the surface treatment agent, although its action is not clear, it is presumed that the heat resistance of the chemical conversion film is improved by the triazole compound being incorporated into the chemical conversion film.

[0026] (Imidazole compound represented by formula (I)) The imidazole compound represented by formula (I) (hereinafter sometimes referred to as imidazole compound (I)) has the following structure.

[0027] [Chemical formula]

[0028] (In formula (I), R1 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzyl group which may have a substituent, a naphthylmethyl group, -CH-(Ph)2, -(CH2) k -Ph, a thienyl group, a thienylmethyl group, a furyl group or a pyridyl group, where Ph represents a phenyl group which may have a substituent, and k represents an integer from 2 to 5. R2 is the same as or different from each other and represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group, provided that the case where R2 is simultaneously a hydrogen atom is excluded.)

[0029] In formula (I), R1 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzyl group which may have a substituent, a naphthylmethyl group, -CH-(Ph)2 (Ph is a phenyl group which may have a substituent.) k -Ph (Ph is a phenyl group which may have a substituent and k is an integer from 2 to 5.), a thienyl group, a thienylmethyl group, a furyl group or a pyridyl group.

[0030] As the linear alkyl group having 1 to 18 carbon atoms, specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group and the like can be mentioned. As the branched alkyl group having 1 to 18 carbon atoms, it is a branched alkyl group having 3 to 18 carbon atoms, specifically, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, s-pentyl group, t-pentyl group, isohexyl group, s-hexyl group, t-hexyl group, isoheptyl group, s-heptyl group, t-heptyl group, isooctyl group, s-octyl group, t-octyl group and the like can be mentioned.

[0031] As the substituent substituting hydrogen of phenyl group, naphthyl group and benzyl group, linear or branched alkyl group having 1 to 18 carbon atoms, phenyl group, methoxy group, ethoxy group, halogen atom and the like can be mentioned.

[0032] Examples of the halogen atom that substitutes the hydrogen of the phenyl group, naphthyl group, and benzyl group include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), and the like. Specific examples of the phenyl group substituted with a halogen atom include a 2-fluorophenyl group, a 3-fluorophenyl group, a 4-fluorophenyl group, a 2-chlorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 2-bromophenyl group, a 3-bromophenyl group, a 4-bromophenyl group, a 2-iodophenyl group, a 3-iodophenyl group, a 4-iodophenyl group, a 2,3-dichlorophenyl group, a 2,4-dichlorophenyl group, a 2,5-dichlorophenyl group, a 2,6-dichlorophenyl group, a 3,4-dichlorophenyl group, a 3,5-dichlorophenyl group, a 2,4,5-trichlorophenyl group, a 3,4,5-trichlorophenyl group, and the like. Specific examples of the benzyl group substituted with a halogen atom include a 2-fluorobenzyl group, a 3-fluorobenzyl group, a 4-fluorobenzyl group, a 2-chlorobenzyl group, a 3-chlorobenzyl group, a 4-chlorobenzyl group, a 2-bromobenzyl group, a 3-bromobenzyl group, a 4-bromobenzyl group, a 2-iodobenzyl group, a 3-iodobenzyl group, a 4-iodobenzyl group, a 2,3-dichlorobenzyl group, a 2,4-dichlorobenzyl group, a 2,5-dichlorobenzyl group, a 2,6-dichlorobenzyl group, a 3,4-dichlorobenzyl group, a 3,5-dichlorobenzyl group, a 2,4,5-trichlorobenzyl group, a 3,4,5-trichlorobenzyl group, and the like.

[0033] Examples of the thienyl group include a 2-thienyl group and a 3-thienyl group, and examples of the furyl group include a 2-furyl group and a 3-furyl group.

[0034] From the viewpoint of the heat resistance of the chemical conversion film, R1 is preferably a linear or branched alkyl group having 1 to 18 carbon atoms, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzyl group which may have a substituent, a naphthylmethyl group, or a thienyl group.

[0035] R2 is a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group. These substituents are the same as those described for R1 above. The two R2s may be the same or different, provided that R2 is not a hydrogen atom at the same time.

[0036] From the viewpoint of the heat resistance of the formation film, R2 is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group. However, the case where R2 is a hydrogen atom at the same time is excluded.

[0037] As the imidazole compound represented by formula (I) (imidazole compound (I)), the imidazole compounds represented by formula (I-1) to formula (I-6) are preferable.

[0038] [Chemical formula]

[0039] (In formula (I-1), R 112 represents a linear or branched alkyl group having 1 to 18 carbon atoms, and R 214 represents a linear or branched alkyl group having 1 to 18 carbon atoms or a phenyl group which may have a substituent, and R 215 represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. In formula (I-2), R 224 represents a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group, and R 225 represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, and R 226 represents, independently or differently, a linear or branched alkyl group having 1 to 18 carbon atoms, a methoxy group, an ethoxy group or a halogen atom, and p represents an integer from 0 to 3. In formula (I-3), R 234represents a phenyl group which may have a substituent, and R 235 represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. In formula (I-4), R 244 represents a phenyl group, naphthyl group or thienyl group which may have a substituent, and R 245 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms or a phenyl group which may have a substituent, and R 246 are the same or different and represent a linear or branched alkyl group having 1 to 18 carbon atoms, a halogen atom, and p represents an integer of 0 to 3. In formula (I-5), R 254 represents a phenyl group which may have a substituent, and R 255 represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. In formula (I-6), R 264 represents a phenyl group or naphthyl group which may have a substituent, and R 265 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms or a phenyl group which may have a substituent.)

[0040] As specific examples of the imidazole compound (I), as the imidazole compound represented by formula (I-1), for example, 2-ethyl-4-methylimidazole, 2-undecyl-4-methylimidazole, 2,4,5-trimethylimidazole, 4,5-dimethyl-2-octylimidazole, 4-(3,4-dichlorophenyl)-5-methyl-2-nonylimidazole, 4-(2,4-dichlorophenyl)-5-methyl-2-undecylimidazole and the like can be mentioned.

[0041] As the imidazole compound represented by formula (I-2), for example, 2,4-diphenylimidazole, 2,4-diphenyl-5-methylimidazole, 2,4 - Diphenyl - 5 - hexylimidazole, 2 - Phenyl - 4 - (2 - chlorophenyl)imidazole, 2 - Phenyl - 4 - (3 - chlorophenyl)imidazole, 2 - Phenyl - 4 - (4 - chlorophenyl)imidazole, 2 - Phenyl - 4 - (4 - fluorophenyl)imidazole, 2 - Phenyl - 4 - (4 - bromophenyl)imidazole, 2 - Phenyl - 4 - (4 - iodophenyl)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 - propyl - 3 - chlorophenyl)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 - (2,3 - 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-(1-naphthyl)imidazole, 2-Phenyl-4-(2-naphthyl)imidazole, 2-Phenyl-4-(1-naphthyl)-5-methylimidazole, 2-Phenyl-4-(2-naphthyl)-5-methylimidazole, 2-Phenyl-4-(2-thienyl)imidazole, 2-Phenyl-4-(3-thienyl)imidazole, 5-Methyl-2-phenyl-4-(2-thienyl)imidazole, 5-Methyl-2-phenyl-4-(3-thienyl)imidazole, 4-(2-Furyl)-2-phenylimidazole, 2-(2-Methylphenyl)-4-phenylimidazole, 2-(3-Octylphenyl)-4-phenylimidazole, 2-(4-Methylphenyl)-4-phenylimidazole, 2-(4-Isopropylphenyl)-4-phenylimidazole, 2-(4-Methylphenyl)-4-phenyl-5-methylimidazole, 2-(4-Isopropylphenyl)-4-phenyl-5-methylimidazole, 2-(4-Biphenyl)-4-phenyl-5-methylimidazole, 2-(2,4-Dimethylphenyl)-4-phenylimidazole, 2-(2-Chlorophenyl)-4-phenylimidazole, 2-(3-Chlorophenyl)-4-phenylimidazole, 2-(4-Chlorophenyl)-4-phenylimidazole, 2-(4-Fluorophenyl)-4-phenylimidazole, 2-(4-Bromophenyl)-4-phenylimidazole, 2-(4-Iodophenyl)-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-(4-Chlorophenyl)-4-phenyl-5-methylimidazole, 4-(2,4-Dichlorophenyl)-2-(4-methoxyphenyl)-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-Heptyl-4-chlorophenyl)-4-phenyl-5-isobutylimidazole, 2,4-Bis(4-chlorophenyl)imidazole, 2-(2,4-Dichlorophenyl)-4-(3,4-dichlorophenyl)-5-methylimidazole, 4-(2,4-Dichlorophenyl)-2-(3,4-dimethoxyphenyl)-5-methylimidazole, 4-(3,4-Dichlorophenyl)-2-(3,4-dimethoxyphenyl)-5-methylimidazole, 2-(4-Methylphenyl)-4-(2-naphthyl)imidazole, 2-(4-Isopropylphenyl)-4-(1-naphthyl)imidazole, 2-(3,4-Dimethoxyphenyl)-4-(1-naphthyl)imidazole, 2-(4-Methylphenyl)-4-(4-chloro-6-butyl-1-naphthyl)imidazole and the like can be mentioned.

[0042] Examples of the imidazole compound represented by formula (I-3) include, for example, 2-(1-Naphthyl)-4-phenylimidazole, 2-(2-Naphthyl)-4-phenylimidazole, 2-(1-Naphthyl)-4-phenyl-5-methylimidazole, 2-(2-Naphthyl)-4-phenyl-5-methylimidazole and the like can be mentioned.

[0043] Examples of the imidazole compound represented by formula (I-4) include, for example, 2-Benzyl-4-phenylimidazole, 2-Benzyl-4-(4-hexylphenyl)imidazole, 2-Benzyl-4-(2-chlorophenyl)imidazole, 2-Benzyl-4-(3-chlorophenyl)imidazole, 2-Benzyl-4-(4-chlorophenyl)imidazole, 2-Benzyl-4-(4-bromophenyl)imidazole, 2-Benzyl-4-(2,3-dichlorophenyl)imidazole, 2-Benzyl-4-(2,4-dichlorophenyl)imidazole, 2-Benzyl-4-(2,5-dichlorophenyl)imidazole, 2-Benzyl-4-(2,6-dichlorophenyl)imidazole, 2-Benzyl-4-(3,4-dichlorophenyl)imidazole, 2-Benzyl-4-(3,5-dichlorophenyl)imidazole, 2-Benzyl-4-(2,4,5-trichlorophenyl)imidazole, 2-Benzyl-4-(3,4,5-trichlorophenyl)imidazole, 2-Benzyl-5-methyl-4-phenylimidazole, 2-Benzyl-5-butyl-4-phenylimidazole, 2-Benzyl-5-heptyl-4-phenylimidazole, 2-Benzyl-5-hexyl-4-phenylimidazole, 2-Benzyl-5-octyl-4-phenylimidazole, 2-Benzyl-4-(2-chlorophenyl)-5-methylimidazole, 2-Benzyl-4-(3-chlorophenyl)-5-methylimidazole, 2-Benzyl-4-(4-chlorophenyl)-5-methylimidazole, 2-Benzyl-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-Benzyl-4-(3,4-dichlorophenyl)-5-methylimidazole, 2-Benzyl-5-methyl-4-(2,4,5-trichlorophenyl)imidazole, 2-Benzyl-4,5-diphenylimidazole, 2-Benzyl-4-(1-naphthyl)imidazole, 2-Benzyl-4-(2-naphthyl)imidazole, 2-(2-Chlorobenzyl)-4-phenylimidazole, 2-(3-Chlorobenzyl)-4-phenylimidazole, 2-(4-Chlorobenzyl)-4-phenylimidazole, 2-(4-Bromobenzyl)-4-phenylimidazole, 2-(4-Chlorobenzyl)-4-(4-chlorophenyl)imidazole, 4-(4-Bromophenyl)-2-(4-chlorobenzyl)imidazole, 2-(4-Bromobenzyl)-4-(4-chlorophenyl)imidazole, 2-(4-Fluorobenzyl)-4-(4-fluorophenyl)imidazole, 2-(2-Bromobenzyl)-4-(4-bromophenyl)imidazole, 2-(4-Bromobenzyl)-4-(3-bromophenyl)imidazole, 4-(4-Butylphenyl)-2-(2-chlorobenzyl)imidazole, 2-(2-Chlorobenzyl)-4-(4-hexylphenyl)imidazole, 2-(2-Chlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(2-Chlorobenzyl)-4-(3,4-dichlorophenyl)imidazole, 2-(3-Chlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(3-Chlorobenzyl)-4-(3,4-dichlorophenyl)imidazole, 2-(4-Chlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(4-Chlorobenzyl)-4-(3,4-dichlorophenyl)imidazole, 2-(4-Chlorobenzyl)-4-(2,4-dibromophenyl)imidazole, 4-(2,4-Dichlorophenyl)-2-(4-methylbenzyl)-5-methylimidazole, 2-(2,3-Dichlorobenzyl)-4-phenylimidazole, 2-(2,4-Dichlorobenzyl)-4-phenylimidazole, 2-(2,5-Dichlorobenzyl)-4-phenylimidazole, 2-(2,6-Dichlorobenzyl)-4-phenylimidazole, 2-(3,4-Dichlorobenzyl)-4-phenylimidazole, 2-(3,5-Dichlorobenzyl)-4-phenylimidazole, 4-(2-Chlorophenyl)-2-(2,4-dichlorobenzyl)imidazole, 4-(2-Chlorophenyl)-2-(3,4-dichlorobenzyl)imidazole, 4-(3-Chlorophenyl)-2-(2,4-dichlorobenzyl)imidazole, 4-(3-Chlorophenyl)-2-(3,4-dichlorobenzyl)imidazole, 4-(4-Chlorophenyl)-2-(2,4-dichlorobenzyl)imidazole, 4-(4-Chlorophenyl)-2-(3,4-dichlorobenzyl)imidazole, 4-(4-Bromophenyl)-2-(2,4-dichlorobenzyl)imidazole, 4-(4-Biphenyl)-2-(2,4-dichlorobenzyl)imidazole, 2-(2,3-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(2,4-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(2,5-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(2,6-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(3,4-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(3,5-Dichlorobenzyl)-4-(2,4-dichlorophenyl)imidazole, 2-(2,3-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole, 2-(2,4-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole, 2-(2,5-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole 2-(2,6-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole 2-(3,4-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole 2-(3,5-Dichlorobenzyl)-4-(3,4-dichlorophenyl)imidazole 4-Phenyl-2-(3,4,5-trichlorobenzyl)imidazole 2-(4-Chlorobenzyl)-5-methyl-4-phenylimidazole 2-(4-Chlorobenzyl)-4-(4-chlorophenyl)-5-methylimidazole 2-(4-Bromobenzyl)-4-(4-bromophenyl)-5-methylimidazole 2-(2-Chlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole 2-(2-Chlorobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole 2-(3-Chlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole 2-(3-Chlorobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole 2-(4-Chlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole 2-(4-Chlorobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole 2-(4-Chlorobenzyl)-4-(2,4-dibromophenyl)-5-methylimidazole 4-(2,4-Dichlorophenyl)-2-(4-fluorobenzyl)-5-methylimidazole 4-(3,4-Dichlorophenyl)-2-(4-fluorobenzyl)-5-methylimidazole 2-(4-Bromobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole 2-(4-Bromobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole, 2-(2,4-Dichlorobenzyl)-5-methyl-4-phenylimidazole, 2-(3,4-Dichlorobenzyl)-5-methyl-4-phenylimidazole, 4-(2-Chlorophenyl)-2-(2,4-dichlorobenzyl)-5-methylimidazole, 4-(2-Chlorophenyl)-2-(3,4-dichlorobenzyl)-5-methylimidazole, 4-(3-Chlorophenyl)-2-(2,4-dichlorobenzyl)-5-methylimidazole, 4-(3-Chlorophenyl)-2-(3,4-dichlorobenzyl)-5-methylimidazole, 4-(4-Chlorophenyl)-2-(2,4-dichlorobenzyl)-5-methylimidazole, 4-(4-Chlorophenyl)-2-(3,4-dichlorobenzyl)-5-methylimidazole, 2-(2,4-Dichlorobenzyl)-5-methyl-4-(4-methylphenyl)imidazole, 2-(2,4-Dichlorobenzyl)-4-(4-methoxyphenyl)-5-methylimidazole, 2-(2,3-Dichlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-(2,4-Dichlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-(2,6-Dichlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-(3,4-Dichlorobenzyl)-4-(2,4-dichlorophenyl)-5-methylimidazole, 2-(2,4-Dichlorobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole, 2-(3,4-Dichlorobenzyl)-4-(3,4-dichlorophenyl)-5-methylimidazole, 2-(2,4-Dibromobenzyl)-4-(3,4-dibromophenyl)-5-methylimidazole, 4-(2,4-Dichlorophenyl)-2-(3,4-dimethoxybenzyl)-5-methylimidazole, 4-(3-Chloro-4-methylphenyl)-2-(2,4-dichlorobenzyl)-5-methylimidazole, 2-(2-Chlorobenzyl)-4,5-diphenylimidazole, 2-(3-Chlorobenzyl)-4,5-diphenylimidazole, 2-(4-Chlorobenzyl)-4,5-diphenylimidazole, 2-(2,4-Dichlorobenzyl)-4,5-diphenylimidazole, 2-(2,4-Dichlorobenzyl)-5-hexyl-4-phenylimidazole, 2-(2-Chlorobenzyl)-4-(1-naphthyl)imidazole, 2-(2-Chlorobenzyl)-4-(2-naphthyl)imidazole, 2-(3-Chlorobenzyl)-4-(1-naphthyl)imidazole, 2-(3-Chlorobenzyl)-4-(2-naphthyl)imidazole, 2-(4-Chlorobenzyl)-4-(1-naphthyl)imidazole, 2-(4-Chlorobenzyl)-4-(2-naphthyl)imidazole, 2-(2,3-Dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(2,3-Dichlorobenzyl)-4-(2-naphthyl)imidazole, 2-(2,4-Dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(2,4-Dichlorobenzyl)-4-(2-naphthyl)imidazole, 2-(2,5-Dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(2,5-Dichlorobenzyl)-4-(2-naphthyl)imidazole, 2-(2,6-Dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(2,6-dichlorobenzyl)-4-(2-naphthyl)imidazole, 2-(3,4-dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(3,4-dichlorobenzyl)-4-(2-naphthyl)imidazole, 2-(3,5-dichlorobenzyl)-4-(1-naphthyl)imidazole, 2-(3,5-dichlorobenzyl)-4-(2-naphthyl)imidazole and the like can be mentioned.

[0044] As the imidazole compound represented by the formula (I-5), for example, 2-(1-naphthylmethyl)-4-phenylimidazole, 2-(2-naphthylmethyl)-4-phenylimidazole, 4-(2-chlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(2-chlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(3-chlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(3-chlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(4-chlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(4-chlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(2,3-dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(2,3-dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(2,4-dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(2,4-dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(2,5-dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(2,5-dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-2-(1-naphthylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-2-(2-naphthylmethyl)imidazole, 5-Methyl-2-(1-naphthylmethyl)-4-phenylimidazole, 5-Methyl-2-(2-naphthylmethyl)-4-phenylimidazole, 4-(2-Chlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(2-Chlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(3-Chlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(3-Chlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(4-Chlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(4-Chlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(2,3-Dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(2,3-Dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(2,4-Dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(2,4-Dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(2,5-Dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(2,5-dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(2,6-dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(2,6-dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(3,4-dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(3,4-dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole, 4-(3,5-dichlorophenyl)-5-methyl-2-(1-naphthylmethyl)imidazole, 4-(3,5-dichlorophenyl)-5-methyl-2-(2-naphthylmethyl)imidazole and the like can be mentioned.

[0045] Examples of the imidazole compound represented by the formula (I-6) include, for example, 4-phenyl-2-(2-thienyl)imidazole, 4-phenyl-2-(3-thienyl)imidazole, 4-(2-chlorophenyl)-2-(2-thienyl)imidazole, 4-(2-chlorophenyl)-2-(3-thienyl)imidazole, 4-(3-chlorophenyl)-2-(2-thienyl)imidazole, 4-(3-chlorophenyl)-2-(3-thienyl)imidazole, 4-(4-chlorophenyl)-2-(2-thienyl)imidazole, 4-(4-chlorophenyl)-2-(3-thienyl)imidazole, 4-(2,3-dichlorophenyl)-2-(2-thienyl)imidazole, 4-(2,3-dichlorophenyl)-2-(3-thienyl)imidazole, 4-(2,4-dichlorophenyl)-2-(2-thienyl)imidazole, 4-(2,4-dichlorophenyl)-2-(3-thienyl)imidazole, 4-(2,5-dichlorophenyl)-2-(2-thienyl)imidazole 4-(2,5-dichlorophenyl)-2-(3-thienyl)imidazole 4-(2,6-dichlorophenyl)-2-(2-thienyl)imidazole 4-(2,6-dichlorophenyl)-2-(3-thienyl)imidazole 4-(3,4-dichlorophenyl)-2-(2-thienyl)imidazole 4-(3,4-dichlorophenyl)-2-(3-thienyl)imidazole 4-(3,5-dichlorophenyl)-2-(2-thienyl)imidazole 4-(3,5-dichlorophenyl)-2-(3-thienyl)imidazole 4-(1-naphthyl)-2-(2-thienyl)imidazole 4-(1-naphthyl)-2-(3-thienyl)imidazole 4-(2-naphthyl)-2-(2-thienyl)imidazole 4-(2-naphthyl)-2-(3-thienyl)imidazole 5-methyl-4-phenyl-2-(2-thienyl)imidazole 5-methyl-4-phenyl-2-(3-thienyl)imidazole 4-(2-chlorophenyl)-5-methyl-2-(2-thienyl)imidazole 4-(2-chlorophenyl)-5-methyl-2-(3-thienyl)imidazole 4-(3-chlorophenyl)-5-methyl-2-(2-thienyl)imidazole 4-(3-chlorophenyl)-5-methyl-2-(3-thienyl)imidazole 4-(4-chlorophenyl)-5-methyl-2-(2-thienyl)imidazole 4-(4-chlorophenyl)-5-methyl-2-(3-thienyl)imidazole 4-(2,3-dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole 4-(2,3-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 4-(2,4-Dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole, 4-(2,4-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 4-(2,5-Dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole, 4-(2,5-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 4-(2,6-Dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole, 4-(2,6-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 4-(3,4-Dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole, 4-(3,4-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 4-(3,5-Dichlorophenyl)-5-methyl-2-(2-thienyl)imidazole, 4-(3,5-Dichlorophenyl)-5-methyl-2-(3-thienyl)imidazole, 5-Methyl-4-(1-naphthyl)-2-(2-thienyl)imidazole, 5-Methyl-4-(1-naphthyl)-2-(3-thienyl)imidazole, 5-Methyl-4-(2-naphthyl)-2-(2-thienyl)imidazole 5-Methyl-4-(2-naphthyl)-2-(3-thienyl)imidazole 4,5-Diphenyl-2-(2-thienyl)imidazole, 4,5-Diphenyl-2-(3-thienyl)imidazole, 4-(2-Chlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(2-Chlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(3-Chlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(3-Chlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(4-Chlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(4-Chlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(2,3-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(2,3-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(2,4-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(2,4-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(2,5-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(2,5-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(2,6-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(2,6-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(3,4-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(3,4-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(3,5-Dichlorophenyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(3,5-Dichlorophenyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(1-Naphthyl)-5-phenyl-2-(2-thienyl)imidazole, 4-(1-Naphthyl)-5-phenyl-2-(3-thienyl)imidazole, 4-(2-Naphthyl)-5-phenyl-2-(2-thienyl)imidazole 4-(2-Naphthyl)-5-phenyl-2-(3-thienyl)imidazole and the like can be mentioned.

[0046] In addition, specific examples of the imidazole compound represented by the formula (I) include, for example, 5-cyclohexyl-2,4-diphenylimidazole, 5-cyclohexyl-2-(2,4-dichlorobenzyl)-4-phenylimidazole, 2-(3,6-dichloro-2-naphthyl)-4-(2-isopropyl-5-fluorophenyl)-5-decylimidazole, 4-phenyl-2-(2-thienylmethyl)imidazole, 4-phenyl-2-(3-thienylmethyl)imidazole, 4-(2-chlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(2-chlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(3-chlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(3-chlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(4-chlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(4-chlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(2,3-dichlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(2,3-dichlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(2,4-dichlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(2,4-dichlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(2,5-dichlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(2,5-dichlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(2,6-dichlorophenyl)-2-(2-thienylmethyl)imidazole, 4-(2,6-dichlorophenyl)-2-(3-thienylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-2-(2-thienylmethyl)imidazole 4-(3,4-Dichlorophenyl)-2-(3-thienylmethyl)imidazole 4-(3,5-Dichlorophenyl)-2-(2-thienylmethyl)imidazole 4-(3,5-Dichlorophenyl)-2-(3-thienylmethyl)imidazole 4-(1-Naphthyl)-2-(2-thienylmethyl)imidazole 4-(1-Naphthyl)-2-(3-thienylmethyl)imidazole 4-(2-Naphthyl)-2-(2-thienylmethyl)imidazole 4-(2-Naphthyl)-2-(3-thienylmethyl)imidazole 5-Methyl-4-phenyl-2-(2-thienylmethyl)imidazole 5-Methyl-4-phenyl-2-(3-thienylmethyl)imidazole 4-(2-Chlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole 4-(2-Chlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole 4-(3-Chlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole 4-(3-Chlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole 4-(4-Chlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole 4-(4-Chlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole 4-(2,3-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole 4-(2,3-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole 4-(2,4-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole 4-(2,4-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole 4-(2,5-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole, 4-(2,5-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-5-methyl-2-(2-thienylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-5-methyl-2-(3-thienylmethyl)imidazole, 5-Methyl-4-(1-naphthyl)-2-(2-thienylmethyl)imidazole, 5-Methyl-4-(1-naphthyl)-2-(3-thienylmethyl)imidazole, 5-Methyl-4-(2-naphthyl)-2-(2-thienylmethyl)imidazole, 5-Methyl-4-(2-naphthyl)-2-(3-thienylmethyl)imidazole, 4,5-Diphenyl-2-(2-thienylmethyl)imidazole, 4,5-Diphenyl-2-(3-thienylmethyl)imidazole, 4-(2-Chlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2-Chlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(3-Chlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(3-Chlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(4-Chlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(4-Chlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(2,3-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2,3-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(2,4-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2,4-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(2,5-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2,5-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2,6-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(3,4-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(3,5-Dichlorophenyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(1-Naphthyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(1-Naphthyl)-5-phenyl-2-(3-thienylmethyl)imidazole, 4-(2-Naphthyl)-5-phenyl-2-(2-thienylmethyl)imidazole, 4-(2-Naphthyl)-5-phenyl-2-(3-thienylmethyl)imidazole and the like can be mentioned.

[0047] (Benzimidazole compound represented by formula (II)) The benzimidazole compound represented by formula (II) (hereinafter sometimes referred to as benzimidazole compound (II)) has the following structure.

[0048]

Chemical formula

[0049] (In formula (II), R3 represents a linear or branched alkyl group having 1 to 18 carbon atoms, -(CH2) m -Ph, -(CH2) m -Np or a group represented by the following formula (1), Ph represents a phenyl group which may have a substituent, Np represents a naphthyl group which may have a substituent, and m represents an integer of 1 to 5.

[0050]

Chemical formula

[0051] (In formula (1), m represents an integer of 1 to 5.) R4 represents, independently or identically, a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a nitro group or a halogen atom.)

[0052] In formula (II), R3 represents a linear or branched alkyl group having 1 to 18 carbon atoms, -(CH2) m -Ph (Ph is a phenyl group which may have a substituent and m is an integer of 1 to 5), -(CH2) m -Np (Np is a naphthyl group which may have a substituent and m is an integer of 1 to 5) or a group represented by the above formula (1).

[0053] The linear and branched alkyl groups having 1 to 18 carbon atoms are the same as those described in the above imidazole compound (I). In addition, the substituents that replace the hydrogen atoms of the phenyl group and naphthyl group are the same as those described in the above imidazole compound (I).

[0054] R4 is a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a nitro group or a halogen atom. The linear alkyl group and branched alkyl group having 1 to 18 carbon atoms are the same as those described in the above imidazole compound (I). Examples of the halogen atom include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), etc. The four R4s may be the same or different.

[0055] From the viewpoint of the heat resistance of the conversion film, R4 is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms or a halogen atom, and more preferably a hydrogen atom, a methyl group or a chlorine atom (Cl).

[0056] As the benzimidazole compound (benzimidazole compound (II)) represented by the formula (II), the benzimidazole compounds represented by the formulas (II-1) to (II-4) are preferable.

[0057]

Chemical formula

[0058] (In the formula (II-1), R 312 represents a linear or branched alkyl group having 1 to 18 carbon atoms, R 415 represents, independently or differently, a linear or branched alkyl group having 1 to 18 carbon atoms or a halogen atom, and q represents an integer from 0 to 3.) In the formula (II-2), X represents, independently or differently, a halogen atom, m represents an integer from 1 to 5, and q represents an integer from 0 to 3. In the formula (II-3), X represents, independently or differently, a halogen atom, m represents an integer from 1 to 5, q represents an integer from 0 to 3, and r represents an integer from 0 to 3. In formula (II-4), X, which may be the same or different, represents a halogen atom, m represents an integer of 1 to 5, and q represents an integer of 0 to 3.)

[0059] Specific examples of the benzimidazole compound (II) include, for example, the benzimidazole compound represented by formula (II-1): 2-Methylbenzimidazole, 2-Ethylbenzimidazole, 2-Propylbenzimidazole, 2-Butylbenzimidazole, 2-tert-Butylbenzimidazole, 2-Pentylbenzimidazole, 2-Hexylbenzimidazole, 2-Heptylbenzimidazole, 2-Octylbenzimidazole, 2-Nonylbenzimidazole, 2-Decylbenzimidazole, 2-Undecylbenzimidazole, 2-Dodecylbenzimidazole, 2-Tridecylbenzimidazole, 2-Tetradecylbenzimidazole, 2-Pentadecylbenzimidazole, 2-Hexadecylbenzimidazole, 2-Heptadecylbenzimidazole, 2-Heptyl-5,6-dimethylbenzimidazole, 2-Octyl-5-chlorobenzimidazole, 2-Pentyl-5,6-dichlorobenzimidazole and the like can be mentioned.)

[0060] Specific examples of the benzimidazole compound represented by formula (II-2) include, for example: 2-(2-Thienylmethyl)benzimidazole, 2-(3-Thienylmethyl)benzimidazole and the like can be mentioned.)

[0061] Examples of the benzimidazole compound represented by the formula (II-3) include 2-(phenylmethyl)benzimidazole, 2-(4-chlorophenylmethyl)benzimidazole, 2-(2,4-dichlorophenylmethyl)benzimidazole, 2-(3,4-dichlorophenylmethyl)benzimidazole, 6-chloro-2-(3,4-dichlorophenylmethyl)benzimidazole, 2-(2-phenylethyl)benzimidazole, 2-[2-(4-chlorophenyl)ethyl]benzimidazole, 2-(3-phenylpropyl)benzimidazole, 2-[3-(2-chlorophenyl)propyl]benzimidazole, 2-(4-phenylbutyl)benzimidazole, 2-[4-(4-chlorophenyl)butyl]benzimidazole, 2-(5-phenylpentyl)benzimidazole, 2-[4-(2,4-dichlorophenyl)butyl]-4,7-dichlorobenzimidazole and the like.

[0062] Examples of the benzimidazole compound represented by the formula (II-4) include 2-(1-naphthylmethyl)benzimidazole, 2-(2-naphthylmethyl)benzimidazole, 2-[2-(1-naphthyl)ethyl]benzimidazole, 2-[2-(2-naphthyl)ethyl]benzimidazole, 2-[3-(1-naphthyl)propyl]benzimidazole, 2-[3-(2-naphthyl)propyl]benzimidazole, 2-[4-(1-naphthyl)butyl]benzimidazole, 2-[4-(2-naphthyl)butyl]benzimidazole, 2-[5-(1-Naphthyl)pentyl]benzimidazole Examples thereof include 2-[5-(2-naphthyl)pentyl]benzimidazole and the like.

[0063] The imidazole compound (I) or the benzimidazole compound (II) is preferably contained in a proportion of 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, and even more preferably 0.05 to 1% by weight based on the total amount of the surface treatment agent. When the content of the imidazole compound (I) or the benzimidazole compound (II) is 0.01% by weight or more, a chemical conversion film can be formed with a film thickness capable of preventing oxidation on the copper surface. Further, when the imidazole compound (I) or the benzimidazole compound (II) is 10% by weight or less, the imidazole compound is easily dissolved in the surface treatment agent, and the solderability of the copper surface can be improved.

[0064] In the practice of the present invention, the imidazole compound selected from the group consisting of the above-described imidazole compound (I) and benzimidazole compound (II) can be used alone or in combination of two or more.

[0065] Further, the imidazole compound (I) and the benzimidazole compound (II) can also be used in a state of forming a salt with a suitable acid. Examples of the acid include HCl (hydrochloric acid), HBr (hydrogen bromide), etc., and they can be used as HCl salts and HBr salts.

[0066] In addition, in the surface treatment agent of the present invention, known imidazole compounds in the same technical field as the present invention can be used in combination with these imidazole compound (I) and benzimidazole compound (II).

[0067] (Triazole compound represented by formula (III)) The triazole compound represented by formula (III) (hereinafter sometimes referred to as triazole compound (III)) has the following structure.

[0068] [Chemical formula]

[0069] (In formula (III), R5 and R6 are the same or different and each represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an amino group, a phenyl group which may have a substituent, a benzyl group which may have a substituent, a naphthyl group, a pyridyl group or a group represented by the following formula (2), provided that the case where both R5 and R6 are the group represented by the following formula (2) is excluded.

[0070] [Chemical formula]

[0071] (In formula (2), t represents an integer from 0 to 12.) R7 represents a hydrogen atom, a benzyl group or -(CH2) n -COOH, and n represents an integer from 1 to 5.)

[0072] In formula (III), R5 and R6 are a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an amino group, a phenyl group which may have a substituent, a benzyl group which may have a substituent, a naphthyl group, a pyridyl group or the group represented by the above formula (2). R5 and R6 may be the same or different, but they will not both be the group represented by the above formula (2) at the same time.

[0073] The linear and branched alkyl groups having 1 to 18 carbon atoms are the same as those described in the above imidazole compound (I). Also, the substituents that replace the hydrogen of the phenyl group and benzyl group are the same as those described in the above imidazole compound (I).

[0074] From the viewpoint of the heat resistance of the formation film, R5 and R6 are preferably a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an amino group, a phenyl group which may have a substituent, a benzyl group having a substituent, a naphthyl group, a pyridyl group, or a group represented by formula (2). Further, in formula (2), t is preferably an integer of 0 to 10, more preferably an integer of 0 to 8, and even more preferably 0 to 6.

[0075] R7 is a hydrogen atom, a benzyl group or -(CH2) n -COOH (n is an integer of 1 to 5). From the viewpoint of the heat resistance of the formation film, R7 is preferably a hydrogen atom, -(CH2) n -COOH (n is an integer of 1 to 3).

[0076] As the triazole compound represented by formula (III) (triazole compound (III)), the imidazole compounds represented by formula (III-1) to formula (III-5) are preferable.

[0077]

Chemical formula

[0078] (In formula (III-1), R 513 represents a hydrogen atom, an amino group or a phenyl group which may have a substituent, and R 515 represents a hydrogen atom, an amino group or a phenyl group which may have a substituent, and s represents an integer of 1 to 3. In formula (III-2), R 523 represents a linear or branched alkyl group having 1 to 18 carbon atoms, or a pyridyl group, and R 525 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a phenyl group which may have a substituent, a benzyl group which may have a substituent, or a pyridyl group. In formula (III-3), R 531 represents a hydrogen atom or a benzyl group which may have a substituent, and R 535represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a phenyl group which may have a substituent, a naphthyl group or an amino group. In formula (III-4), R 545 represents a hydrogen atom, a phenyl group which may have a substituent or a benzyl group which may have a substituent. In formula (III-5), t represents an integer from 0 to 6. )

[0079] As specific examples of the triazole compound (III), as the triazole compound represented by formula (III-1), for example, 1,2,4-triazole-1-acetic acid, 1,2,4-triazole-1-propionic acid, 1,2,4-triazole-1-butyric acid, 3-amino-1,2,4-triazole-1-acetic acid, 3-amino-5-phenyl-1,2,4-triazole-1-acetic acid and the like can be mentioned.

[0080] As the triazole compound represented by formula (III-2), for example, 3-methyl-1,2,4-triazole, 3-ethyl-1,2,4-triazole, 3-propyl-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 3-butyl-1,2,4-triazole, 3-pentyl-1,2,4-triazole, 3-hexyl-1,2,4-triazole, 3-octyl-1,2,4-triazole, 3-undecyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, 3-ethyl-5-methyl-1,2,4-triazole, 3-methyl-5-propyl-1,2,4-triazole, 3-isopropyl-5-methyl-1,2,4-triazole, 3-Butyl-5-methyl-1,2,4-triazole, 3-Methyl-5-pentyl-1,2,4-triazole, 5-Heptyl-3-methyl-1,2,4-triazole, 5-Methyl-3-octyl-1,2,4-triazole, 3-Methyl-5-undecyl-1,2,4-triazole, 3,5-Diethyl-1,2,4-triazole, 3,5-Dipropyl-1,2,4-triazole, 3,5-Diisopropyl-1,2,4-triazole, 3,5-Dibutyl-1,2,4-triazole, 3,5-Dipentyl-1,2,4-triazole, 3,5-Diheptyl-1,2,4-triazole, 3,5-Dioctyl-1,2,4-triazole, 3,5-Diundecyl-1,2,4-triazole, 3-Methyl-5-phenyl-1,2,4-triazole, 3-Ethyl-5-phenyl-1,2,4-triazole, 5-Phenyl-3-propyl-1,2,4-triazole, 3-Butyl-5-phenyl-1,2,4-triazole, 3-Pentyl-5-phenyl-1,2,4-triazole, 3-Methyl-5-(phenylmethyl)-1,2,4-triazole, 3-Ethyl-5-(phenylmethyl)-1,2,4-triazole, 5-(Phenylmethyl)-3-propyl-1,2,4-triazole, 3-Methyl-5-(4-pyridyl)-1,2,4-triazole, 3,5-Bis(4-pyridyl)-1,2,4-triazole and the like can be mentioned.

[0081] Examples of the triazole compound represented by the formula (III-3) include, for example, 3-Amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 3-amino-5-methyl-1,2,4-triazole, 3-amino-5-ethyl-1,2,4-triazole, 3-amino-5-propyl-1,2,4-triazole, 3-amino-5-isopropyl-1,2,4-triazole, 3-amino-5-butyl-1,2,4-triazole, 3-amino-5-pentyl-1,2,4-triazole, 3-amino-5-phenyl-1,2,4-triazole, 3-amino-5-(1-naphthyl)-1,2,4-triazole, 3-amino-5-(2-naphthyl)-1,2,4-triazole, 1-benzyl-3,5-diamino-1,2,4-triazole and the like can be mentioned.

[0082] Examples of the triazole compound represented by the formula (III-4) include, 3-phenyl-1,2,4-triazole, 3-benzyl-5-phenyl-1,2,4-triazole, 3,5-diphenyl-1,2,4-triazole and the like can be mentioned.

[0083] Examples of the triazole compound represented by the formula (III-5) include, 3,3'-bis(5-amino-1,2,4-triazole), 3,3'-methylenebis(5-amino-1,2,4-triazole), 3,3'-ethylenebis(5-amino-1,2,4-triazole), 3,3'-trimethylenebis(5-amino-1,2,4-triazole), 3,3'-tetramethylenebis(5-amino-1,2,4-triazole), 3,3'-pentamethylenebis(5-amino-1,2,4-triazole), Examples thereof include 3,3′-hexamethylenebis(5-amino-1,2,4-triazole).

[0084] The triazole compound (III) is preferably contained in a proportion of 0.005 to 1% by weight, more preferably 0.01 to 0.5% by weight, and even more preferably 0.01 to 0.3% by weight, based on the total amount of the surface treatment agent.

[0085] In the practice of the present invention, it is possible to use one or more selected from the above-mentioned triazole compounds (III) in combination, and it is also possible to use in combination a known triazole compound in the same technical field as the present invention together with this triazole compound.

[0086] In the present invention, the triazole compound (III) is preferably contained in a molar ratio of 0.005 to 3.0, more preferably 0.01 to 2.7, and even more preferably 0.05 to 2.5, relative to the imidazole compound (I) or the benzimidazole compound (II). When the ratio of the triazole compound (III) to the imidazole compound (I) or the benzimidazole compound (II) is within the above range, a chemical conversion film with high heat resistance can be formed.

[0087] The surface treatment agent of the present invention is prepared by dissolving the imidazole compound (I) or the benzimidazole compound (II) and the triazole compound (III) in water. Thereby, a water-soluble preflux can be obtained.

[0088] The water is not particularly limited, and examples thereof include tap water, ion-exchanged water, purified water, pure water, etc.

[0089] The surface treatment agent of the present invention preferably contains a solubilizing agent in order to easily dissolve (aqueous solution) an imidazole compound (I) or a benzimidazole compound (II) and a triazole compound (III) in water. As the solubilizing agent, for example, it is preferable to use an organic acid or an inorganic acid (these may be referred to as acids).

[0090] Typical organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, isobutyric acid, 2-ethylbutyric acid, oleic acid, glycolic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, gluconic acid, glyceric acid, tartaric acid, malic acid, citric acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, iodoacetic acid, methoxyacetic acid, ethoxyacetic acid, propoxyacetic acid, butoxyacetic acid, 2-(2-methoxyethoxy)acetic acid, 2-[2-(2-ethoxyethoxy)ethoxy]acetic acid, 2-{2-[2-(2-ethoxyethoxy)ethoxy]ethoxy}acetic acid, 3-methoxypropionic acid, 3-ethoxypropionic acid, 3-propoxypropionic acid, 3-butoxypropionic acid, levulinic acid, glyoxylic acid, pyruvic acid, acetoacetic acid, acrylic acid, crotonic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, benzoic acid, p-nitrobenzoic acid, picric acid, salicylic acid, p-toluenesulfonic acid, methanesulfonic acid, sulfamic acid, etc. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc. These acids can be used alone or in combination of two or more.

[0091] The solubilizing agent is preferably contained in a proportion of 0.1 to 50% by weight, more preferably 0.1 to 40% by weight, based on the total amount of the surface treatment agent. When the proportion of the solubilizing agent is within the above range, it becomes easier to dissolve the imidazole compound (I) or the benzimidazole compound (II) and the triazole compound (III) in water, and it also becomes easier to form a chemical conversion film.

[0092] In the practice of the present invention, an organic solvent can be used in combination with the above-mentioned solubilizer. Examples of such organic solvents include alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, ethylene glycol, and tetrahydrofurfuryl alcohol; cellosolves such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; or those freely miscible with water such as acetone, N,N-dimethylformamide, and acetylacetone, which are preferably used. These organic solvents can be used alone or in combination of two or more.

[0093] The organic solvent is preferably contained in a proportion of 0.1 to 50% by weight, more preferably 1 to 40% by weight, based on the total amount of the surface treatment agent.

[0094] The surface treatment agent of the present invention preferably contains halide ions in order to further improve the formation rate (film-forming property) of the chemical conversion film and the heat resistance of the film. Examples of halide ions include fluoride ions, chloride ions, bromide ions, iodide ions, etc., and it may contain one kind alone or two or more kinds. Among them, from the viewpoint of improving the heat resistance of the chemical conversion film, it is more preferable for the surface treatment agent to contain chloride ions.

[0095] The halide ions are preferably contained in a proportion of 0.005 to 1% by weight, more preferably 0.01 to 0.1% by weight, based on the total amount of the surface treatment agent.

[0096] Halide ions can be contained by adding a halogen compound to the surface treatment agent. Examples of the halogen compound include sodium fluoride, potassium fluoride, ammonium fluoride, sodium chloride, potassium chloride, ammonium chloride, chloropropionic acid, sodium bromide, potassium bromide, ammonium bromide, bromopropionic acid, sodium iodide, potassium iodide, ammonium iodide, iodopropionic acid, etc. It may be used alone or in combination of two or more.

[0097] The surface treatment agent of the present invention preferably contains zinc ions in order to further enhance the heat resistance of the formed chemical conversion film. Zinc ions are preferably contained in a proportion of 0.05 to 2% by weight, more preferably 0.1 to 1% by weight.

[0098] Zinc ions can be contained by adding a zinc compound as an auxiliary agent to the surface treatment agent. Examples of this zinc compound include zinc oxide, zinc formate, zinc acetate, zinc oxalate, zinc lactate, zinc citrate, zinc sulfate, zinc nitrate, zinc phosphate, zinc chloride, zinc bromide, zinc iodide, etc. It may be used alone or in combination of two or more.

[0099] The surface treatment agent of the present invention preferably contains copper ions in order to accelerate the formation rate (film-forming property) of the chemical conversion film on the surface of copper. Copper ions are preferably contained in a proportion of 0.005 to 1% by weight, more preferably 0.01 to 0.1% by weight, based on the total amount of the surface treatment agent.

[0100] Copper ions can be contained by adding a copper compound as an auxiliary agent to the surface treatment agent. Examples of this copper compound include copper formate, copper acetate, copper oxalate, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, copper iodide, copper hydroxide, copper phosphate, copper sulfate, copper nitrate, etc. It may be used alone or in combination of two or more.

[0101] In addition to the aforementioned halogen compounds, zinc compounds, and copper compounds, the surface treatment agent of the present invention can contain metal compounds such as manganese compounds, cobalt compounds, and nickel compounds, and coordination compounds such as crown ethers, bipyridines, porphyrins, and phenanthrolines as auxiliary agents for the purpose of improving the film-forming property of the chemical conversion film and improving the physical properties of the chemical conversion film. Examples of the manganese compound include manganese formate, manganese chloride, manganese oxalate, manganese sulfate, and manganese carbonate. Examples of the cobalt compound include cobalt acetate, cobalt sulfate, and cobalt nitrate. Examples of the nickel compound include nickel chloride, nickel acetate, nickel nitrate, nickel carbonate, and nickel sulfate. These metal compounds can be used alone or in combination of two or more, and are preferably contained in a proportion of 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, based on the total amount of the surface treatment agent. Also, these coordination compounds can be used alone or in combination of two or more, and are preferably contained in a proportion of 0.05 to 2% by weight, more preferably 0.1 to 1% by weight, based on the total amount of the surface treatment agent.

[0102] The surface treatment agent of the present invention can contain a chelating agent and / or an iron compound as an auxiliary agent in order to improve the film-forming property of the chemical conversion film on the surface of copper while suppressing the formation of the chemical conversion film on the surface of gold (Au) (see Japanese Patent Laid-Open No. 9-291372, which is incorporated herein by reference).

[0103] Examples of the chelating agent include iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, 1,2-diaminocyclohexanetetraacetic acid, glycol ether diamine tetraacetic acid, N,N-bis(2-hydroxybenzyl)ethylenediamine diacetic acid, ethylenediamine dipropionic acid, ethylenediamine diacetic acid, diaminopropanol tetraacetic acid, hexamethylenediamine tetraacetic acid, hydroxyethyliminodiacetic acid, diaminopropane tetraacetic acid, nitrilotripropionic acid, ethylenediamine-N,N'-disuccinic acid, ethylenediaminetetrakis(methylenephosphonic acid), nitrilotris(methylenephosphonic acid), 2-phosphonobutane-1,2,4-tricarboxylic acid, and salts thereof. The chelating agent is preferably contained in a proportion of 0.01 to 0.4% by weight.

[0104] From the viewpoint of the film-forming property (formation rate) of the chemical conversion film, the surface treatment agent of the present invention preferably has a pH of 2.0 to 5.0, more preferably 2.2 to 4.8, and even more preferably 2.5 to 4.5.

[0105] When lowering the pH of the surface treatment agent, the aforementioned organic acid or inorganic acid can be used, and when raising the pH, a base can be used. Examples of the base include sodium hydroxide, potassium hydroxide, ammonia, and amines such as monoethanolamine, diethanolamine, triethanolamine, and triisopropanolamine. As the base, substances having a buffering action such as amines are preferably used.

[0106] By bringing the surface treatment agent of the present invention into contact with the surface of copper, a chemical conversion film can be formed on the surface of copper. When treating the surface of copper using the surface treatment agent of the present invention, it is preferable to set the liquid temperature of the surface treatment agent in the range of 10 to 70°C and the contact time in the range of 1 second to 10 minutes. Examples of the contact method between copper and the surface treatment agent for treating the surface of copper include means such as dipping, spraying, and coating.

[0107] After bringing the surface treatment agent into contact with the surface of the copper, it is preferable to perform water washing if necessary, and then dry the surface of the copper. The drying is preferably carried out at a temperature of room temperature (for example, 20 ° C) to 150 ° C, preferably 60 to 120 ° C, for a time of 1 second to 10 minutes, preferably about 10 seconds to 3 minutes. As the water used for water washing, pure water such as ion-exchanged water, distilled water, and purified water is preferable. There are no particular restrictions on the method and time of water washing, and an appropriate time by a method such as a spray method or an immersion method may be used.

[0108] Before bringing the surface treatment agent into contact with the surface of the copper, a pre-dip solution containing an azole compound may be brought into contact with the surface of the copper. This pre-dip solution has a function of enhancing the film-forming property of the chemical conversion film formed on the surface of the copper. The azole compound is not particularly limited, and examples include commercially available imidazole compounds, triazole compounds, and tetrazole compounds. The pre-dip solution contains water and additives in addition to the azole compound. As the additives, for example, the aforementioned organic solvents, amines, copper compounds, halogen compounds, and other additives (for example, ammonium salts such as ammonium sulfate, ammonium formate, ammonium acetate, ammonium chloride, ammonium carbonate, and ammonium nitrate) may be contained.

[0109] The film thickness of the chemical conversion film (OSP film) formed by the surface treatment agent of the present invention is preferably 0.10 to 0.50 μm. When the film thickness of the film is 0.10 μm or more, sufficient heat resistance can be imparted, and thus the desired effect of the present invention can be obtained. When the film thickness of the film is 0.50 μm or less, good solderability can be maintained.

[0110] As the solder used in the practice of the present invention, in addition to the conventionally known Sn-Pb eutectic solder, lead-free solders such as Sn-Ag-Cu, Sn-Ag-Bi, Sn-Bi, Sn-Ag-Bi-In, Sn-Zn, and Sn-Cu can be mentioned.

[0111] The soldering method of the present invention can also be applied to a flow method in which a printed wiring board on which electronic components are mounted is moved while being brought into contact with the liquid surface of molten solder in a solder bath to solder the joint between the electronic components and the printed wiring board, or a reflow method in which paste-like cream solder is printed on the printed wiring board in advance in accordance with a circuit pattern, electronic components are mounted thereon, the printed wiring board is heated to melt the solder, and soldering is performed.

Example

[0112] Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited thereto.

[0113] [Imidazole compound] The imidazole compounds used in the examples are as follows.

[0114] (Synthesis Example 1) (Synthesis of 4-(3,4-dichlorophenyl)-5-methyl-2-nonylimidazole (A-1)) In accordance with the method described in JP-A-2010-77071, the imidazole compound "4-(3,4-dichlorophenyl)-5-methyl-2-nonylimidazole" (sometimes abbreviated as "A-1") was synthesized.

[0115] (Synthesis Example 2) (Synthesis of 2-phenyl-4-(1-naphthyl)-5-methylimidazole (A-2)) In accordance with the method described in JP-A-2006-36683, the imidazole compound "2-phenyl-4-(1-naphthyl)-5-methylimidazole" (sometimes abbreviated as "A-2") was synthesized.

[0116] (Synthesis Example 3) (Synthesis of 5-methyl-4-phenyl-2-(2-thienyl)imidazole (A-3)) According to the method described in JP-A-2014-37370, the imidazole compound "5-methyl-4-phenyl-2-(2-thienyl)imidazole" (sometimes abbreviated as "A-3") was synthesized.

[0117] (Synthesis Example 4) (Synthesis of 2-(3-chlorobenzyl)-4-(1-naphthyl)imidazole (A-4)) According to the method described in JP-A-2010-90105, the imidazole compound "2-(3-chlorobenzyl)-4-(1-naphthyl)imidazole" (sometimes abbreviated as "A-4") was synthesized.

[0118] The chemical formulas of the imidazole compounds A-1 to A-4 are shown below.

[0119] [Chemical formula]

[0120] [Benzimidazole compound] The benzimidazole compounds used in the examples are as follows.

[0121] (Synthesis Example 5) (Synthesis of 2-nonylbenzimidazole (B-1)) According to the method described in JP-A-5-107814, the benzimidazole compound "2-nonylbenzimidazole" (sometimes abbreviated as "B-1") was synthesized.

[0122] (Synthesis Example 6) (Synthesis of 6-chloro-2-(3,4-dichlorophenylmethyl)benzimidazole (B-2)) The benzimidazole compound "6-chloro-2-(3,4-dichlorophenylmethyl)benzimidazole" (sometimes abbreviated as "B-2") was synthesized by the following method. 133.0 g (0.715 mol) of 3,4-dichlorobenzyl cyanide and 190 g of dehydrated dichloromethane were mixed, and 36.4 g (0.790 mol) of dehydrated ethanol was further added. While stirring under ice cooling, 29.6 g (0.812 mol) of hydrogen chloride gas was blown in little by little, and then stirred at 5 °C or lower overnight. The resulting product was concentrated under reduced pressure to obtain 192.1 g (0.715 mol, yield 100%) of ethyl 2-(3,4-dichlorophenyl)ethanecarboximidate hydrochloride as a white powder. 25.4 g (0.178 mol) of 4-chloro-1,2-phenylenediamine and 200 mL of dehydrated methanol were mixed, and then 48.0 g (0.179 mol) of ethyl 2-(3,4-dichlorophenyl)ethanecarboximidate hydrochloride was added. After stirring under reflux for 2 hours, 23.6 g of 25% aqueous ammonia was further added. Then, it was concentrated under reduced pressure to obtain 76.4 g of a black-brown tarry product. This product was stirred in hot water, and the resulting solid was filtered while hot, pulverized in a mortar, 400 mL of water was added, heated, then cooled for crystallization, and filtered to obtain black-violet crystals. Methanol and activated carbon were added, heated and stirred, and the filtrate obtained by filtration was concentrated under reduced pressure. The resulting product was recrystallized from acetonitrile to obtain 33.7 g (0.108 mol, yield 60.9%) of 6-chloro-2-(3,4-dichlorophenylmethyl)benzimidazole as a milky white powder.

[0123] (Synthesis Example 7) (Synthesis of 2-(2-naphthylmethyl)benzimidazole (B-3)) The benzimidazole compound "2-(2-naphthylmethyl)benzimidazole" (sometimes abbreviated as "B-3") was synthesized by the following method. 50.9 g (0.273 mol) of 2-naphthylacetic acid and 29.5 g (0.273 mol) of o-phenylenediamine were mixed and heated until the outflow of water ceased to obtain a purple solid. After pulverizing the obtained solid in a mortar, 1 L of water and 88 g of sodium carbonate were added and stirred under reflux for 30 minutes. After hot filtration, the same operation was performed again on the obtained solid. Methanol and activated carbon were added thereto, heated and stirred, and water was gradually added as a poor solvent to the filtrate obtained by filtration for crystallization. The obtained crystals were washed with methanol and water and then dried to obtain 39.4 g (0.153 mol, yield 55.8%) of 2-(2-naphthylmethyl)benzimidazole as pale yellow crystals.

[0124] The chemical formulas of the benzimidazole compounds of B-1 to B-3 are shown below.

[0125]

Chemical formula

[0126] [Triazole compound] The triazole compounds used in the examples are as follows.

[0127] (Synthesis Example 8) (Synthesis of 3-amino-1,2,4-triazole-1-acetic acid (C-1)) The triazole compound "3-amino-1,2,4-triazole-1-acetic acid" (sometimes abbreviated as "C-1") was synthesized by the following method. 30.1 g (0.357 mol) of 3-amino-1,2,4-triazole and 200 mL of methanol were mixed, and an aqueous sodium hydroxide solution prepared by previously mixing 14.5 g (0.363 mol) of sodium hydroxide and 80.0 g of water was added thereto little by little. Then, 41.6 g (0.357 mol) of sodium monochloroacetate was added and heated, and stirred under reflux overnight. After the obtained product was concentrated under reduced pressure, 100 mL of water was added, and 36.1 g of 36% hydrochloric acid was added little by little while cooling. After the precipitate was filtered, it was washed with water and dried to obtain 24.3 g (0.171 mol, yield 47.8%) of 3-amino-1,2,4-triazole-1-acetic acid as a white powder.

[0128] (Synthesis Example 9) (Synthesis of 5-methyl-3-octyl-1,2,4-triazole (C-2)) The triazole compound "5-methyl-3-octyl-1,2,4-triazole" (sometimes abbreviated as "C-2") was synthesized by the following method. After mixing 37.26 g (0.200 mol) of ethyl nonanoate and 100 g of methanol, 20.02 g (0.400 mol) of hydrazine monohydrate was further added at room temperature and stirred for 1 hour, then heated and stirred under reflux overnight. The crystals precipitated by cooling were filtered, washed with a small amount of methanol, and dried to obtain 28.26 g (0.164 mol, yield 82.0%) of nonanoic acid hydrazide as white scaly crystals. After mixing 15.60 g (0.165 mol) of acetamidine hydrochloride and 100 g of methanol, 34.72 g (0.180 mol) of 28% sodium methoxide / methanol solution and further 25.84 g (0.150 mol) of nonanoic acid hydrazide were added. After stirring under reflux overnight, it was cooled and filtered to remove NaCl, and then the filtrate was concentrated under reduced pressure. 80 g of toluene and 80 g of water were added to the obtained concentrate, the product was dissolved in toluene, this organic layer was separated, and then concentrated under reduced pressure until the total amount reached 40 g. This concentrated solution was cooled for crystallization, then filtered and dried to obtain 20.51 g (0.105 mol, yield 70.0%) of 5-methyl-3-octyl-1,2,4-triazole as a white powder.

[0129] (Synthesis Example 10) (Synthesis of 3-Benzyl-5-phenyl-1,2,4-triazole (C-3)) The triazole compound "3-benzyl-5-phenyl-1,2,4-triazole" (sometimes abbreviated as "C-3") was synthesized by the following method. After mixing 31.3 g (0.200 mol) of benzamidine hydrochloride and 300 mL of ethanol, a solution prepared by previously mixing 240 mL of ethanol and 14.0 g (0.259 mol) of sodium methoxide was added. After filtering off the precipitated NaCl, 30.0 g (0.200 mol) of phenylacetic acid hydrazide was added to the resulting filtrate. After stirring for 1 hour under reflux, the reaction solution was concentrated under reduced pressure to obtain 55.1 g of a tarry product. Water was added and stirred, and the resulting solid was filtered, dried once, recrystallized from diethyl ether, and dried to obtain 14.4 g (0.061 mol, yield 30.6%) of 3-benzyl-5-phenyl-1,2,4-triazole as a white powder.

[0130] (Synthesis Example 11) (Synthesis of 3,3′-Methylenebis(5-amino-1,2,4-triazole) (C-4)) The triazole compound "3,3′-methylenebis(5-amino-1,2,4-triazole)" (sometimes abbreviated as "C-4") was synthesized according to the method described in Russ. J. Applied Chem., 82(2), 276(2009).

[0131] The chemical formulas of the triazole compounds C-1 to C-4 are shown below.

[0132]

Chemical formula

[0133] The evaluation test methods adopted in the examples and comparative examples are as follows.

[0134] [Evaluation test of solder joint rate] As test specimens, printed wiring boards made of glass epoxy resin with dimensions of 120 mm (length) × 150 mm (width) × 1.6 mm (thickness) and having 300 holes each of copper through-holes with inner diameters of 0.60, 0.80, and 1.00 mm were used. These test specimens were subjected to soft etching, water washing, and drying under the following conditions, then immersed in a predip solution maintained at a predetermined liquid temperature for a predetermined time, washed with water and dried, and then immersed in a surface treatment agent maintained at a predetermined liquid temperature for a predetermined time, and then washed with water and dried to perform surface treatment, thereby forming a chemical conversion film with a thickness of approximately 0.2 μm on the copper surface. Regarding the test specimens subjected to this surface treatment, reflow heating was performed under the conditions described in Tables 1 to 6 using an infrared and hot air reflow apparatus (product name: SNR-725GT-MH, manufactured by Senju Metal Industry Co., Ltd.), and then soldering was performed using a flow soldering apparatus (conveyor speed: 1.0 m / min). The solder used was "Eco Solder M705" (product name, lead-free solder of Sn-3.0Ag-0.5Cu) manufactured by Senju Metal Industry Co., Ltd., and the flux used for soldering was "ES-1062V-1" (product name) manufactured by Senju Metal Industry Co., Ltd. Also, the solder temperature was set to 250°C. Regarding the test specimens subjected to soldering, the number of through-holes to which the solder rose (was soldered) up to the upper land portion of the copper through-holes was measured, and the ratio (%) with respect to the total number of through-holes (900 holes) was calculated (solder rise rate). The greater the wettability of the solder with respect to the copper surface, the easier it is for the molten solder to penetrate into the copper through-holes and rise up to the upper land portion of the through-holes. That is, the greater the ratio of the number of through-holes to which the solder rose up to the upper land portion with respect to the total number of through-holes, the better the wettability of the solder with respect to copper and the better the solderability is determined to be.

[0135] [Surface treatment of test specimens] The test specimens were processed according to the following steps i to iii. i. Acid cleaning / 1 minute (room temperature), water washing, drying / 1 minute (100°C) ii. Immersion in a predip solution ("PT20" manufactured by Shikoku Kasei Kogyo Co., Ltd.) / 30 seconds (30°C), water washing, drying / 1 minute (100°C) iii. Immersion in the surface treatment solution / 1 minute (40 °C), rinsing with water, drying / 1 minute (100 °C)

[0136] (Example 1) 2-(3-chlorobenzyl)-4-(1-naphthyl)imidazole (A-4), 3-amino-1,2,4-triazole-1-acetic acid (C-1), acetic acid and heptanoic acid were dissolved in ion-exchanged water, and then adjusted to pH 3.20 with aqueous ammonia to prepare a surface treatment agent having the composition shown in Table 1. Using the obtained surface treatment agent, the above-mentioned evaluation test of the solder wetting rate was carried out, and the solder wetting rate (%) was measured. The reflow conditions were as described in Table 1, with the peak temperature being 260 °C and the number of heating times being 2 times. The test results were as shown in Table 1.

[0137] (Examples 2 to 16, Comparative Examples 1 to 4) In the same manner as in Example 1, a surface treatment agent was prepared according to the compositions shown in Tables 1 to 2. Using the obtained surface treatment agent, an evaluation test of the solder wetting rate was carried out under the treatment conditions shown in Tables 1 to 2, and the solder wetting rate (%) was measured. These test results were as shown in Tables 1 to 2.

[0138]

Table 1

[0139]

Table 2

[0140] From the comparison between Examples 1 to 4 and Comparative Example 1, Examples 5 to 8 and Comparative Example 2, Examples 9 to 12 and Comparative Example 3, and Examples 13 to 16 and Comparative Example 4, by incorporating a triazole compound (III) together with an imidazole compound (I) or a benzimidazole compound (II) in the surface treatment agent, the solder wetting rate was improved. From this, it was found that the surface treatment agents of Examples 1 to 16 were excellent in the heat resistance of the resulting conversion film.

[0141] (Examples 17 - 20, Comparative Examples 5 - 8) In the same manner as in Example 1, a surface treatment agent was prepared according to the composition shown in Table 3. Using the obtained surface treatment agent, an evaluation test of the soldering-up rate was conducted under the treatment conditions shown in Table 3, and the soldering-up rate (%) was measured. These test results were as shown in Table 3.

[0142]

Table 3

[0143] From the comparison between Example 17 and Comparative Example 5, Example 18 and Comparative Example 6, Example 19 and Comparative Example 7, and Example 20 and Comparative Example 8, even in a system containing bromide ions and iodide ions as halide ions, by including the triazole compound (III) together with the imidazole compound (I) or the benzimidazole compound (II) in the surface treatment agent, the soldering-up rate was improved.

[0144] (Examples 21 - 30, Comparative Examples 9 - 18) In the same manner as in Example 1, a surface treatment agent was prepared according to the composition shown in Tables 4 - 5. Using the obtained surface treatment agent, an evaluation test of the soldering-up rate was conducted under the treatment conditions shown in Tables 4 - 5, and the soldering-up rate (%) was measured. These test results were as shown in Tables 4 - 5.

[0145]

Table 4

[0146]

Table 5

[0147] As imidazole compounds (I), 4-(3,4-dichlorophenyl)-5-methyl-2-nonylimidazole (A-1), 2-phenyl-4-(1-naphthyl)-5-methylimidazole (A-2) and 5-methyl-4-phenyl-2-(2-thienyl)imidazole (A-3) were added. Also, when 6-chloro-2-(3,4-dichlorophenylmethyl)benzimidazole (B-2) and 2-(2-naphthylmethyl)benzimidazole (B-3) were used as benzimidazole compounds (II), the soldering-up rate was improved by including a triazole compound (III) together with the imidazole compound (I) or benzimidazole compound (II) in the surface treatment agent.

[0148] (Examples 31 - 32, Comparative Examples 19 - 20) In the same manner as in Example 1, a surface treatment agent was prepared according to the composition shown in Table 6. Using the obtained surface treatment agent, an evaluation test of the soldering-up rate was conducted under the treatment conditions shown in Table 6, and the soldering-up rate (%) was measured. These test results were as shown in Table 6.

[0149]

Table 6

[0150] From the comparison between Example 31 and Comparative Example 19, and Example 32 and Comparative Example 20, even in a system containing metal ions, the soldering-up rate was improved by including a triazole compound (III) together with the imidazole compound (I) in the surface treatment agent.

Industrial Applicability

[0151] According to the present invention, when an electronic component or the like is joined to a printed wiring board using solder, a chemical conversion film excellent in heat resistance and wettability with solder is formed on the surface of copper or a copper alloy constituting the circuit part or the like of the printed wiring board, thereby providing a surface treatment agent and a surface treatment method with good soldering properties.

Claims

1. A surface treatment agent for copper or a copper alloy, comprising an imidazole compound represented by the following chemical formula (I) or a benzimidazole compound represented by the following chemical formula (II), and a triazole compound represented by the following chemical formula (III-1), the following chemical formula (III-2), the following chemical formula (III-4) or the following chemical formula (III-5). 【Chemical 1】 (In formula (I), R １ represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a benzyl group which may have a substituent, a naphthylmethyl group, -CH-(Ph) ２ , -(CH ２ ) ｋ -Ph, a thienyl group, a thienylmethyl group, a furyl group or a pyridyl group, where Ph represents a phenyl group which may have a substituent, and k represents an integer of 2 to 5. R ２ is, independently or identically, a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a thienyl group or a furyl group. However, R ２ excluding the case where R is simultaneously a hydrogen atom.) [Chemical Formula 2] In formula (II), R ３ represents a linear or branched alkyl group having 1 to 18 carbon atoms, —(CH ２ ) ｍ —Ph, —(CH ２ ) ｍ —Np or a group represented by the following formula (1), Ph represents a phenyl group which may have a substituent, Np represents a naphthyl group which may have a substituent, and m represents an integer of 1 to 5. [Chemical 3] (In formula (1), m represents an integer of 1 to 5.) R ４ represents, independently or identically, a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a nitro group or a halogen atom. 【Chemical Formula 4】 (In formula (III-1), R513 represents a hydrogen atom, an amino group or a phenyl group which may have a substituent, R515 represents a hydrogen atom, an amino group or a phenyl group which may have a substituent, and s represents an integer of 1 to 3.) (In formula (III-2), R523 represents a linear or branched alkyl group having 1 to 18 carbon atoms, or a pyridyl group, and R525 represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a phenyl group which may have a substituent, a benzyl group which may have a substituent or a pyridyl group.) (In formula (III-4), R545 represents a hydrogen atom, a phenyl group which may have a substituent or a benzyl group which may have a substituent.) (In formula (III-5), t represents an integer of 0 to 6.)

2. The surface treatment agent for copper or a copper alloy according to claim 1, further containing a halide ion.

3. The surface treatment agent for copper or a copper alloy according to claim 2, wherein the halide ion is a chloride ion.

4. The surface treatment agent for copper or a copper alloy according to any one of claims 1 to 3, further containing a zinc ion.

5. The surface treatment agent for copper or a copper alloy according to any one of claims 1 to 4, wherein the triazole compound represented by the chemical formula (III-1), the chemical formula (III-2), the chemical formula (III-4) or the chemical formula (III-5) is contained in a molar ratio of 0.005 to 3.0 with respect to the imidazole compound represented by the chemical formula (I) or the benzimidazole compound represented by the chemical formula (II).

6. The surface treatment agent for copper or a copper alloy according to any one of claims 1 to 5, wherein the pH is 2 to 5.

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