HK1090098B

HK1090098B - Novel imidazole compound and usage thereof

Info

Publication number: HK1090098B
Application number: HK06110659.5A
Authority: HK
Inventors: 村井孝行; 菊川芳昌; 平尾浩彦
Original assignee: 四国化成工业株式会社
Priority date: 2003-03-19
Filing date: 2004-03-18
Publication date: 2010-09-24

Description

Novel imidazole compound and use thereof

Technical Field

The present invention relates to a novel imidazole compound, a surface treatment agent and a composition for copper or a copper alloy for soldering using a lead-free flux, a surface treatment method for copper or a copper alloy, and a soldering method for copper or a copper alloy.

Background

In recent years, surface mounting technology that can improve mounting density has been widely adopted. Such surface mounting methods are classified into two-sided surface mounting in which chip components are bonded with paste-like flux, and mixed mounting in which surface mounting of chip components using paste-like flux and through-hole mounting of discrete components are combined. In any mounting method, soldering is performed on a printed circuit board many times, and thus each time the printed circuit board is exposed to high temperature, severe thermal history is experienced.

The formation of an oxide film on the surface of copper or a copper alloy constituting a circuit portion of a printed wiring board is promoted by heating, and thus, the good solderability of the circuit surface cannot be maintained.

In order to protect the copper circuit portion of such a printed wiring board from air oxidation, a treatment of forming a chemical treatment film on the surface of the circuit by using a surface treatment agent is widely performed, but it is required to protect the copper circuit portion from being subjected to a plurality of thermal history, and thus the chemical treatment film is not changed or deteriorated, thereby maintaining good solderability.

At present, eutectic solder of tin-lead alloy is widely used for bonding electronic parts on printed circuit boards and the like, but in recent years, since lead is contained in those solder alloys, there is a fear of harmfulness to human bodies, and it is necessary to use solder not containing lead.

For this reason, various lead-free solders have been studied, and for example, lead-free solders in which tin is used as a base metal and metals such as silver, zinc, bismuth, indium, antimony, and copper are added have been proposed.

The conventional tin-lead eutectic solder has high reliability because it has good wettability to the surface of a bonding base material, particularly copper, and is strongly bonded to copper. On the other hand, if a lead-free solder is used, it has poor wettability to the copper surface compared with the conventional tin-lead solder, so that the solder performance is poor, a bonding defect such as void occurs, and the bonding strength is also low.

Therefore, when a lead-free solder is used, it is required to select a solder alloy having good soldering properties and a solder suitable for the lead-free solder. Further, the surface treatment agent used for preventing oxidation of the surface of copper or copper alloy is also required to have a function of improving the wettability of the lead-free solder to have good solderability.

Further, since many lead-free solders have a high melting point and a soldering temperature higher by about 20 to 50 ℃ than the conventional tin-lead eutectic solder, a chemical treatment film having excellent heat resistance is formed on a surface treatment agent in soldering with the lead-free solder.

Many imidazole compounds such as 2-alkylimidazole, 2-arylimidazole, 2-alkylbenzimidazole, 2-arylbenzimidazole, and 2-aralkylbenzimidazole compounds have been studied as the active ingredient of the surface treatment agent, but any imidazole compound is considered to be used for a tin-lead eutectic solder, and when it is used for soldering with a lead-free solder, the wettability of the solder is insufficient, and satisfactory soldering properties cannot be obtained.

For example, U.S. Pat. No. 5498301, U.S. Pat. No. 5560785 and European patent publication No. 0627499 disclose surface-treating agents containing, as an active ingredient, imidazole compounds represented by the following general formula (A) and having aryl groups at the 2-and 4-positions of the imidazole ring.

General formula (A)

(wherein R represents a hydrogen atom or a methyl group, R₁And R₂Represents a hydrogen atom, a lower alkyl group or a halogen atom. R₃And R₄Represents a hydrogen atom, a lower alkyl group, a halogen atom, a lower alkoxy group, a di-lower alkylamino group, a cyano group or a nitro group. ) In example 10 of these documents, a surface treatment agent containing 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole as an active ingredient is disclosed, and a solder wettability test and a solder paste ductility test using the surface treatment agent are described.

However, the solder used in these tests is a tin-lead eutectic solder, and there is no disclosure at all of the fact that the solder wettability is improved and the solder has good solderability when a lead-free solder is used.

Further, Japanese patent application laid-open No. 7-243053 discloses 2, 4-diphenylimidazole and 2, 4-diphenyl-5-methylimidazole as surface treatment agents for copper and copper alloys. In the examples of this publication, 2, 4-diphenylimidazole and 2, 4-diphenyl-5-methylimidazole are described as surface treating agents for copper and copper alloys, respectively, and particularly as treating agents for improving the solder wettability and solder overflow property of a lead-containing paste solder. Further, this publication describes a method for synthesizing 2, 4-diphenylimidazole represented by the following reaction formula (1),

Reaction formula (1)

(in reaction formula 1, X represents a chlorine atom or a bromine atom.)

And a method for synthesizing 2, 4-diphenyl-5-methylimidazole represented by the following reaction formula (2).

Reaction type (2)

Further, U.S. Pat. No. 5498301 (page 4) and European patent publication No. 0627499 (page 5), which correspond to Japanese patent application laid-open No. 7-243053, disclose that 2-phenyl-4- (dichlorophenyl) imidazole and 2-phenyl-4- (dichlorophenyl) -5-methylimidazole in which the hydrogen atom of the phenyl group at the 4-position is substituted by 2 chlorine atoms, are useful as surface treating agents for copper, particularly for improving the solder wettability and the flux overflow property of a lead-containing paste solder. These documents disclose a method for producing an imidazole compound having a substituent on each of phenyl groups at the 2-position and 4-position by the following 2 reaction formulae (3) and (4).

Reaction type (3)

(in the formula, R₁And R₂Represents a hydrogen atom, a lower alkyl group or a halogen atom. R₃And R₄Represents a hydrogen atom, a lower alkyl group, a halogen atom, a lower alkoxy group, a di-lower alkylamino group or a nitro group. )

Reaction type (4)

(in the formula, R_1aAnd R_2aRepresents a hydrogen atom, a lower alkyl group or a halogen atom. R_3aAnd R_4aRepresents a hydrogen atom, a lower alkyl group, a halogen atom, a lower alkoxy group, a di-lower alkylamino group or a nitro group. )

However, the synthesis of 2-phenyl-4- (dichlorophenyl) imidazole and 2-phenyl-4- (dichlorophenyl) -5-methylimidazole is not described in U.S. Pat. No. 5498301 and European patent No. 0627499, and these compounds are not assigned CAS registry number (CAS Registry number).

In particular, the reaction formula (4) appears to reveal that a 2-phenyl-4- (dichlorophenyl) -5-methylimidazole compound having a methyl group at the 5-position can be synthesized from benzaldehyde, a 1- (dichlorophenyl) -1, 2-propanedione compound and ammonium acetate. However, in practice, benzaldehyde and ammonium acetate are readily available as industrial chemicals, whereas the 1- (dichlorophenyl) -1, 2-propanedione compound is not commercially available as an industrial chemical or reagent and is therefore only available synthetically.

U.S. Pat. No. 4107210 discloses a method for synthesizing a 1-phenyl-1, 2-propanedione compound. Therefore, the present inventors tried to synthesize 1- (2, 4-dichlorophenyl) -1, 2-propanedione and 1- (3, 4-dichlorophenyl) -1, 2-propanedione by the disclosed method, but in either case the reaction was complicated and an appropriate purification method could not be found, and the desired product could not be isolated. Therefore, the synthesis of 2-phenyl-4- (dichlorophenyl) -5-methylimidazole compounds based on the teaching of reaction formula (4) has not been successful.

Further, in the above-mentioned U.S. Pat. No. 5498301 (example 10 described in the left column at page 4, line 27 and right column at page 7), U.S. Pat. No. 5560785 (example 10 described in the left column at page 4, line 24 and left column at page 7) and European patent publication No. 0627499 (example 10 described in the 1 st line at page 6, page 10), examples of the use of 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole as a surface treatment agent for copper are described.

However, other imidazole compounds in which the phenyl group at the 2-position is substituted with 2 chlorine atoms are not known.

Disclosure of Invention

It is a first object of the present invention to provide a novel imidazole compound useful as a surface treatment agent for copper and copper alloys.

It is a second object of the present invention to provide a composition for surface treatment of copper or a copper alloy, which can provide good solderability between the surface of copper or a copper alloy constituting a circuit portion of a printed wiring board and a lead-free solder when an electronic component or the like is bonded to the printed wiring board using the lead-free solder.

A third object of the present invention is to provide a method for surface treatment of copper or a copper alloy, which can provide good solderability between the surface of copper or a copper alloy constituting a circuit portion of a printed wiring board and a lead-free solder when an electronic component or the like is bonded to the printed wiring board using the lead-free solder.

A fourth object of the present invention is to provide a soldering method capable of obtaining good solderability to the surface of copper or a copper alloy when using a lead-free solder.

In order to achieve the above object, the present inventors have made extensive studies and the following findings have been obtained.

(i) The imidazole compound represented by the following general formula (1) is a useful compound as a component of an aqueous composition for surface treatment of copper or a copper alloy, particularly a component of an aqueous composition for surface treatment for forming a chemically treated film when a lead-free solder is applied.

General formula (1)

(in the formula, R¹Represents a hydrogen atom or a methyl group. R²And R³Represents a chlorine atom, and R⁴And R⁵Represents a hydrogen atom, or R²And R³Represents a hydrogen atom, and R⁴And R⁵Represents a chlorine atom. )

(ii) Specifically, a printed wiring board containing a copper circuit portion is treated with a surface treatment composition containing these compounds, whereby a chemical treatment film having excellent heat resistance, that is, capable of withstanding a high soldering temperature of a lead-free solder can be formed on the surface of the copper circuit.

(iii) Further, when a printed wiring board containing a copper circuit portion is treated with a surface treatment composition containing these compounds and soldering is performed using a lead-free solder, the wettability of the lead-free solder with respect to the surface of copper or a copper alloy can be improved, and as a result, good solderability, particularly solder overflow property and solder ductility can be obtained.

The present invention has been completed based on the above findings, and provides the following imidazole compounds and the like.

1. An aqueous composition for surface treatment of copper or a copper alloy, characterized by containing an imidazole compound represented by the following general formula (1) and being used for soldering using a lead-free solder.

2. The composition according to item 1, wherein the compound represented by the general formula (1) is R¹A compound representing a methyl group.

3. The composition according to item 1, wherein the compound represented by the general formula (1) is R²And R³Represents a hydrogen atom, R⁴And R⁵A compound representing a chlorine atom.

4. The composition according to item 3, wherein the compound represented by the general formula (1) is at least 1 selected from the group consisting of 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole and 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole.

5. The composition according to item 1, wherein the compound represented by the general formula (1) is R²And R³Represents a chlorine atom, R⁴And R⁵A compound representing a hydrogen atom.

6. The composition according to item 5, wherein the compound represented by the general formula (1) is at least 1 selected from the group consisting of 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole and 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole.

7. The composition according to item 1, which is characterized by containing the compound represented by the general formula (1) in an amount of 0.01 to 10% by weight based on the total weight of the composition.

8. An aqueous composition for surface treatment of copper or a copper alloy, characterized by containing an imidazole compound represented by the following general formula (1) and an acid, and being used for soldering using a lead-free solder.

9. The aqueous composition according to item 8, wherein the acid is at least 1 selected from the group consisting of a saturated or unsaturated aliphatic monocarboxylic acid having 1 to 12 carbon atoms, a saturated or unsaturated aliphatic dicarboxylic acid having 2 to 6 carbon atoms, an aromatic carboxylic acid having 7 to 8 carbon atoms, an aromatic sulfonic acid having 6 to 8 carbon atoms, hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid.

10. The aqueous composition according to item 8, wherein the imidazole compound represented by the general formula (1) is contained in an amount of 0.01 to 10% by weight based on the total weight of the composition, the acid is at least 1 selected from the group consisting of a saturated or unsaturated aliphatic monocarboxylic acid having 1 to 12 carbon atoms, a saturated or unsaturated aliphatic dicarboxylic acid having 2 to 6 carbon atoms, an aromatic carboxylic acid having 7 to 8 carbon atoms, an aromatic sulfonic acid having 6 to 8 carbon atoms, hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and the acid is contained in an amount of 0.1 to 50% by weight based on the total weight of the composition.

11. The aqueous composition according to item 8, further comprising a copper compound.

12. The aqueous composition according to claim 11, wherein the copper compound is at least 1 selected from the group consisting of copper halides, copper salts of acids, and copper hydroxides.

13. The aqueous composition according to claim 11, wherein the copper compound is at least 1 selected from the group consisting of a copper halide, an acid copper salt and a copper hydroxide, and the content of the copper compound is 0.01 to 10% by weight based on the total weight of the composition.

14. The aqueous composition according to item 8, further comprising a zinc compound.

15. The aqueous composition of claim 14 wherein the zinc compound is selected from at least 1 of zinc oxide and zinc salts of acids.

16. The aqueous composition according to claim 14, wherein the zinc compound is at least 1 selected from zinc oxide and zinc salts of acids, and the content ratio of the zinc compound is 0.01 to 10% by weight based on the total weight of the composition.

17. The aqueous composition according to item 8, further comprising a halogen compound.

18. The aqueous composition of claim 17, wherein the halogen compound is at least 1 selected from the group consisting of alkali metal halides and ammonium halides.

19. The aqueous composition according to claim 17, wherein the halogen compound is at least 1 selected from the group consisting of alkali metal halides and ammonium halides, and the content of the halogen compound is 0.001 to 1% by weight based on the total weight of the composition.

20. The aqueous composition according to item 8, further comprising an organic solvent.

21. The aqueous composition of claim 20, wherein the organic solvent is at least 1 selected from the group consisting of lower alcohols, acetone, N-dimethylformamide, ethylene glycol, and glycol ethers.

22. The aqueous composition according to item 20, wherein the organic solvent is at least 1 selected from the group consisting of lower alcohols, acetone, N-dimethylformamide, ethylene glycol and glycol ethers, and the content of the organic solvent is 1 to 50% by weight based on the total weight of the composition.

23. A method for treating a surface of copper or a copper alloy, characterized in that a material containing copper or a copper alloy is brought into contact with the aqueous composition described in any one of items 1 to 22 and used for soldering using a lead-free solder.

24. A soldering method comprising a step of bringing a material containing copper or a copper alloy into contact with the aqueous composition described in any one of items 1 to 22, and a step of soldering the material containing copper or the copper alloy with a lead-free solder.

25. Use of an aqueous treating agent comprising a compound represented by the following general formula (1) as a surface treating agent for copper or a copper alloy for soldering using a lead-free solder.

26. The use according to claim 25, wherein the compound represented by the general formula (1) is R¹A compound representing a methyl group.

27. The use according to claim 25, wherein the compound represented by the general formula (1) is R²And R³Represents a hydrogen atom, R⁴And R⁵A compound representing a chlorine atom.

28. The use according to claim 27, wherein the compound represented by the general formula (1) is at least 1 selected from the group consisting of 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole and 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole.

29. The use according to claim 25, wherein the compound represented by the general formula (1) is R²And R³Represents a chlorine atom, R⁴And R⁵A compound representing a hydrogen atom.

30. The use according to claim 29, wherein the compound represented by the general formula (1) is at least 1 selected from the group consisting of 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole and 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole.

31. An imidazole compound represented by the following general formula (1).

(in the formula, R¹Represents a hydrogen atom or a methyl group. R²And R³Represents a chlorine atom, and R⁴And R⁵Represents a hydrogen atom, or R²And R³Represents a hydrogen atom, and R⁴And R⁵Represents a chlorine atom. But with the exception of 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole. )

32. A compound of claim 31, wherein R is¹Represents a methyl group.

33. A compound of claim 31, wherein R is²And R³Represents a hydrogen atom, R⁴And R⁵Represents a chlorine atom.

34. The compound of claim 33 is 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole.

35. A compound of claim 31, wherein R is²And R³Represents a chlorine atom, R⁴And R⁵Represents a hydrogen atom.

36. The compound of claim 35 which is 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole or 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole.

When the imidazole compound of the present invention is used as a treating agent for a surface of copper or a copper alloy constituting a circuit portion of a printed wiring board or the like, a chemical treatment film having excellent heat resistance can be formed on the surface, and wettability of a lead-free solder to the surface can be remarkably improved, and as a result, the lead-free solder can have good solderability.

The imidazole compound of the present invention is suitably used in soldering using a flux not containing lead, and therefore is a useful compound from the viewpoint of environmental protection.

These compounds are also useful as epoxy resin hardeners, pharmaceutical intermediates, and the like.

Detailed Description

The present invention will be described in detail below.

(A) Imidazole compounds

The imidazole compound of the present invention is a novel compound not described in the literature, and is a compound represented by the following general formula (1).

The imidazole compound of the present invention is roughly classified into a 2-phenyl-4- (dichlorophenyl) imidazole compound represented by the following general formula (2)

(in the formula, R¹As above. )

And 2- (dichlorophenyl) -4-phenylimidazole compounds represented by the following general formula (3) (except for 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole, however).

(in the formula, R¹As above. )

The 2-phenyl-4- (dichlorophenyl) imidazole compounds represented by the general formula (2) include 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-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 and 2-phenyl-4- (3, 5-dichlorophenyl) -5-methylimidazole.

The 2- (dichlorophenyl) -4-phenylimidazole compound represented by the general formula (3) includes 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, 3-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 and 2- (3, 5-dichlorophenyl) -4-phenyl-5-methylimidazole.

Among the 2-phenyl-4- (dichlorophenyl) imidazole compounds, in addition to the solderability, from the viewpoints of easy availability of raw materials and easy synthesis, 2-phenyl-4- (dichlorophenyl) -5-methylimidazole compounds having a methyl group at the 5-position of the imidazole ring are preferred, and among them, 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole and 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole are preferred.

Among the 2- (dichlorophenyl) -4-phenylimidazole compounds, in addition to good solderability, from the viewpoints of easy availability of raw materials and easy synthesis, 2- (dichlorophenyl) -4-phenyl-5-methylimidazole compounds having a methyl group at the 5-position of the imidazole ring are preferred, and 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole is more preferred.

Process for producing 2-phenyl-4- (dichlorophenyl) imidazole compound represented by general formula (2)

The 2-phenyl-4- (dichlorophenyl) imidazole compound can be synthesized according to a known method. That is, as shown in the following reaction formula (5), a dichlorophenylalkylketone compound halogenated at the 2-position and a benzamidine compound (typically, benzamidine exemplified in reaction formula (5)) are reacted by heating in an organic solvent in the presence of a dehydrohalogenating agent to obtain a 2-phenyl-4- (dichlorophenyl) imidazole compound.

Reaction type (5)

(in the formula, R¹Represents a hydrogen atom or a methyl group, and X represents a chlorine atom, a bromine atom or an iodine atom. )

Specifically, a dichlorophenylalkylketone compound (2-2) halogenated at the 2-position and a benzamidine compound (2-1) in a proportion of about 0.8 to 1.5 mol, preferably about 0.9 to 1.1 mol, based on 1mol of the compound (2-2) are reacted in a solvent at room temperature to reflux temperature in the presence of a dehalogenating agent in a proportion of about 1 to 10 mol, based on 1mol of the compound (2-2), for about 1 to 10 hours to produce a 2-phenyl-4- (dichlorophenyl) imidazole compound. The reaction may be carried out generally at atmospheric pressure.

Then, a large amount of water is added to the reaction solution or the concentrate after the solvent is distilled off, whereby a solid crude 2-phenyl-4- (dichlorophenyl) imidazole compound can be obtained. The crude product can be purified by recrystallization.

Representative examples of the 2-position-halogenated dichlorophenyl alkyl ketone compound (2-2) used for producing the 2-phenyl-4- (dichlorophenyl) imidazole compound of the present invention include 2, 2 ', 3 ' -trichloroacetophenone, 2, 2 ', 4 ' -trichloroacetophenone, 2-bromo-2 ', 5 ' -dichloroacetophenone, 2-iodo-2 ', 6 ' -dichloroacetophenone, 2-bromo-3 ', 4 ' -dichloroacetophenone, 2-bromo-3 ', 5 ' -dichloroacetophenone, 2-bromo-2 ', 3 ' -dichloropropiophenone, 2, 2 ', 4 ' -trichloropropiophenone, 2-bromo-2 ', 5 ' -dichloroacetone, 2-bromo-2 ', 6 ' -dichloropropiophenone, 2-bromo-3 ', 4 ' -dichloropropiophenone, 2-iodo-3 ', 5 ' -dichloropropiophenone, and the like.

Of these 2-position halogenated dichlorophenyl alkyl ketone compounds, 2, 2 ', 4' -trichloroacetophenone may be used as a reagent, and others may be synthesized by 2-position halogenation of dichlorophenyl alkyl ketone. Of the 2-position halogenation, both 2-position chlorination and 2-position iodination are possible, but 2-position bromination with bromine is the simplest. That is, dichlorophenylalkyl ketone of dichloroacetophenone or dichloropropiophenone can be easily produced by reacting 1 mole of bromine.

Examples of the benzamidine compound include organic acid salts of benzamidine such as benzamidine and benzamidine acetate; and inorganic acid salts of benzamidine such as benzamidine hydrochloride.

As the dehydrohalogenation agent, known dehydrohalogenation agents can be used without limitation. Examples of the known dehydrohalogenation agents include inorganic bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, and potassium hydrogencarbonate; organic bases such as triethylamine and 1, 8-diazacyclo [5, 4, 0] -7-undecene (DBU); and metal alkoxide compounds such as sodium methoxide and potassium tert-butoxide.

The solvent may be any known solvent as long as it can dissolve the 2-position halogenated dichlorophenylalkylketone compound and the benzamidine compound without affecting the reaction. Examples of the known solvent include alcohols such as ethanol and isopropanol; hydrocarbons such as hexane and toluene; halogenated hydrocarbons such as chloroform and chlorobenzene; esters such as ethyl acetate; nitriles such as acetonitrile; ethers such as tetrahydrofuran and dioxane; amides such as Dimethylformamide (DMF) and Dimethylacetamide (DMAC); dimethyl sulfoxide (DMSO), and the like.

Process for producing 2- (dichlorophenyl) -4-phenylimidazole compound represented by general formula (3)

Among the 2- (dichlorophenyl) -4-phenylimidazole compounds of the present invention, the 2- (dichlorophenyl) -4-phenylimidazole compound (3H) unsubstituted at the 5-position of the imidazole ring can be obtained, for example, by heating 2-acetoxyacetophenone (3-1), a dichlorobenzaldehyde compound (3-2), ammonia, and copper (II) acetate in an alcohol as shown in the following reaction formula (6).

Reaction type (6)

In the reaction of the reaction formula (6), the amount of 2-acetoxyacetophenone (3-1) used may be about 0.8 to 1.5 mol, preferably about 0.9 to 1.1 mol, based on 1mol of the dichlorobenzaldehyde compound (3-2), the amount of ammonia used may be about 10 to 50 mol, preferably about 20 to 30 mol, based on 1mol of the dichlorobenzaldehyde compound (3-2), and the amount of copper acetate (II) used may be about 1 to 5mol, preferably about 2 to 3 mol, based on 1mol of the dichlorobenzaldehyde compound (3-2).

2-Acetoacetophenone (3-1) can be obtained by reacting 2-chloroacetophenone, acetic acid and potassium acetate (see reference example 1 described later). Examples of the dichlorobenzaldehyde compound (3-2) to be used include 2, 3-dichlorobenzaldehyde, 2, 4-dichlorobenzaldehyde, 2, 5-dichlorobenzaldehyde, 2, 6-dichlorobenzaldehyde, 3, 4-dichlorobenzaldehyde and 3, 5-dichlorobenzaldehyde, and these compounds are known compounds which can be easily obtained. Examples of the alcohol as the reaction solvent include methanol, ethanol, propanol, and isopropanol.

The reaction temperature may be about 50 to 80 ℃ and the reaction time may be about 1 to 10 hours. The reaction can be carried out generally at atmospheric pressure.

After the heating was completed, a precipitate was collected by filtration and suspended in methanol. Then, a small amount of sodium hydrosulfide was gradually added to the methanol suspension in a proportion of about 0.5 to 0.8 mol based on 1mol of the dichlorobenzaldehyde compound (3-2) until no more consumption was observed, the precipitated copper sulfide was filtered off, methanol was distilled off under reduced pressure, and the residue was washed with water to obtain a solid crude 2- (dichlorophenyl) -4-phenylimidazole compound (3H). The crude product can be purified by recrystallization.

Further, the 2- (dichlorophenyl) -4-phenyl-5-methylimidazole compound (3M) having the 5-position of the imidazole ring substituted with a methyl group is obtained by heating a dichlorobenzaldehyde compound (3-2), 1-phenyl-1, 2-propanedione (3-3) and ammonium acetate in acetic acid to react, as shown in the following reaction formula (7).

Reaction type (7)

In the reaction of the reaction formula (7), the 1-phenyl-1, 2-propanedione (3-3) may be used in an amount of about 0.8 to 1.5 mol, preferably about 0.9 to 1.1 mol, based on 1mol of the dichlorobenzaldehyde compound (3-2). The amount of ammonium acetate to be used may be about 2 to 10 moles, preferably about 4 to 6 moles, based on 1 mole of the dichlorobenzaldehyde compound (3-2).

The reaction temperature may be 80 ℃ or higher, preferably about reflux temperature, and the reaction time may be about 1 to 10 hours. The reaction can be carried out generally at atmospheric pressure.

After the heating, the reaction solution or the residue obtained by distilling acetic acid from the reaction solution is mixed with an aqueous solution containing an alkali agent such as sodium hydroxide, sodium carbonate, or ammonia in an excess amount to the acetic acid contained in the residue, at a ratio of 5 to 20 times by weight of the aqueous solution to the residue, whereby a crude 2- (dichlorophenyl) -4-phenyl-5-methylimidazole compound (3M) as a solid precipitate can be obtained. The precipitate taken out can be purified by recrystallization.

(B) Aqueous composition for surface treatment of copper or copper alloy

The imidazole compound represented by the general formula (1) is suitably used as a component of an aqueous composition for surface treatment of copper or a copper alloy to be soldered using a lead-free solder, and particularly as an active ingredient. That is, the composition of the present invention is an aqueous composition for surface treatment of copper or a copper alloy containing the compound represented by the above general formula (1) and used for soldering using a lead-free solder.

The compound represented by the above general formula (1) in the composition of the present invention includes a 2-phenyl-4- (dichlorophenyl) imidazole compound represented by the following general formula (2)

(in the formula, R¹Same as above)

And a 2- (dichlorophenyl) -4-phenylimidazole compound represented by the following general formula (3). The number of the compounds represented by the general formula (1) contained in the composition of the present invention may be 1, or 2 or more.

(in the formula, R¹Same as above)

Among the compounds represented by the general formula (1), the 2-phenyl-4- (dichlorophenyl) imidazole compounds include 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-dichlorophenyl) -5-methylimidazole, and 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 and 2-phenyl-4- (3, 5-dichlorophenyl) -5-methylimidazole.

The 2- (dichlorophenyl) -4-phenylimidazole compounds among the compounds represented by the general formula (1) include 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, 3-dichlorophenyl) -4-phenyl-5-methylimidazole, and 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 and 2- (3, 5-dichlorophenyl) -4-phenyl-5-methylimidazole.

These imidazole compounds are characterized by having a basic skeleton of a 2, 4-diphenylimidazole compound having phenyl groups bonded to 2-and 4-positions of an imidazole ring, and the phenyl group at the 2-or 4-position is substituted with 2 chlorine atoms.

Among the 2-phenyl-4- (dichlorophenyl) imidazole compounds represented by the general formula (2), 2-phenyl-4- (dichlorophenyl) -5-methylimidazole compounds having a methyl group at the 5-position of the imidazole ring are preferable, and 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole and 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole are preferable, from the viewpoint of good flux overflow and flux ductility and from the viewpoint of easy aqueous solution described later.

Among the 2- (dichlorophenyl) -4-phenylimidazole compounds represented by the general formula (3), 2- (dichlorophenyl) -4-phenyl-5-methylimidazole compounds having a methyl group at the 5-position of the imidazole ring are preferable, and 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole and 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole are more preferable, from the viewpoints of good flux overflow property, flux ductility and easiness in aqueous solution.

The aqueous composition of the present invention preferably contains an acid in addition to the imidazole compound represented by the above general formula (1).

The content of the imidazole compound in the aqueous composition may be preferably about 0.01 to 10% by weight, and more preferably about 0.1 to 5% by weight, based on the total weight of the composition. When the content ratio of the imidazole compound is within the above range, a chemical treatment film having a practically sufficient thickness can be formed on the copper surface, whereby oxidation of the copper surface can be sufficiently prevented, and the composition can be formed into a uniform aqueous solution without dissolution and residue of the imidazole compound in the composition.

The composition of the present invention preferably contains an organic acid or an inorganic acid in order to dissolve the imidazole compound in water. Typical examples of the organic acid include saturated or unsaturated aliphatic monocarboxylic acids having 1 to 12 carbon atoms (more preferably 1 to 3 carbon atoms) such as formic acid, acetic acid, propionic acid, butyric acid, heptanoic acid, octanoic acid, decanoic acid, lauric acid, glycolic acid, lactic acid, and acrylic acid; saturated or unsaturated aliphatic dicarboxylic acids having 2 to 6 carbon atoms such as oxalic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, and adipic acid; aromatic carboxylic acids having 7 to 8 carbon atoms such as benzoic acid, p-nitrobenzoic acid, salicylic acid and the like; aromatic sulfonic acids having 6 to 8 carbon atoms such as p-toluenesulfonic acid; picric acid, and the like. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid.

Since the acid reacts with the basic imidazole compound to form a salt which is easily dissolved in water and also functions as an organic solvent, the acid is preferably an organic acid, more preferably a saturated or unsaturated aliphatic monocarboxylic acid having 1 to 12 carbon atoms, and still more preferably formic acid, acetic acid, propionic acid, or lactic acid. The acid may be used alone in 1 kind, or in a mixture of 2 or more kinds.

The amount of the acid used is an amount that allows the compound of the general formula (1) to be effectively dissolved in water. Specifically, the amount of the acid used is preferably about 0.1 to 50% by weight, more preferably about 1 to 40% by weight, based on the total weight of the composition. Within the above range, the imidazole compound can be sufficiently dissolved, and deterioration of the working environment due to generation of odor can be avoided, and the working is not difficult due to increased corrosivity of the water-soluble composition.

In addition, the imidazole compound may contain a small amount of an organic solvent, if necessary, in addition to the acid, in order to dissolve the imidazole compound in water. As the organic solvent, an organic solvent freely miscible with water can be used without limitation. Examples of such organic solvents include lower alcohols such as methanol, ethanol and isopropanol, acetone, N-dimethylformamide, ethylene glycol and glycol ethers.

As the organic solvent, ethylene glycol and glycol ethers are preferable from the viewpoint of making the imidazole compound easily soluble in water. The organic solvent may be used alone in 1 kind, or in combination of 2 or more kinds.

The composition of the present invention may or may not contain an organic solvent, and when the composition contains an organic solvent, the amount used is an amount that allows the compound of the general formula (1) to be effectively dissolved in water. Typical amounts are preferably from about 1 to about 50 wt%, more preferably from about 1 to about 40 wt%, based on the total weight of the composition. Within the above range, the imidazole compound can be sufficiently dissolved without increasing the risk of flammability, combustibility and the like of the water-soluble composition.

The composition of the present invention may contain a copper compound as needed in order to accelerate the formation of a chemical treatment film on the surface of copper or a copper alloy.

For these copper compounds, known copper compounds can be used without limitation. Typical examples of the known copper compound include copper halides such as cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, and cupric iodide; copper salts of acids such as copper acetate, copper phosphate, copper sulfate, and copper nitrate; copper hydroxide, and the like. Among them, copper halides and copper salts are preferable.

The copper compound may be used alone in 1 kind, or in combination of 2 or more kinds. The copper compound may be used or not, but is used in an amount effective to accelerate the formation of a chemical treatment film on the surface of copper or a copper alloy when the copper compound is contained in the composition, and is typically used in an amount of about 0.01 to 10% by weight, more preferably about 0.02 to 5% by weight, based on the total weight of the composition. Within the above range, the rate of formation of the chemically treated film can be sufficiently increased while avoiding precipitation of the imidazole compound due to the salting-out effect.

The composition of the present invention may contain a zinc compound as necessary in order to further improve the heat resistance of the formed chemical treatment film. The zinc compound is not particularly limited as long as it is water-soluble. As representative of these zinc compounds, there can be mentioned zinc oxide; zinc salts of acids such as zinc formate, zinc acetate, zinc oxalate, zinc lactate, zinc citrate, zinc chloride, zinc sulfate, zinc nitrate, and zinc phosphate. Among them, zinc formate, zinc acetate, and zinc chloride are preferable.

The zinc compound may be used alone or in combination of 1 or more than 2, and the amount of the zinc compound used in the case of containing the zinc compound in the composition is an amount effective for improving the heat resistance of the chemical treatment film, and is typically preferably about 0.01 to 10% by weight, more preferably about 0.02 to 5% by weight, based on the total weight of the composition.

When a copper compound or a zinc compound is used, a basic substance having a buffering action, such as amines such as ammonia and organic amine compounds, is added in addition to an organic acid or an inorganic acid to stabilize the pH of the solution; or hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and magnesium hydroxide. By adding these basic substances, the pH of the composition is preferably maintained at about 1 to 6. That is, the amount of the alkaline substance used is preferably an amount that can maintain the pH of the composition.

The surface treatment composition of the present invention may contain a halogen compound for further improving the rate of formation of a chemical treatment film and the heat resistance of the chemical treatment film. As the halogen compound, a halide of an alkali metal, an ammonium halide, or the like can be used. Specific examples thereof include fluorine compounds such as sodium fluoride, potassium fluoride and ammonium fluoride; chlorides such as sodium chloride, potassium chloride, and ammonium chloride; bromides such as sodium bromide, potassium bromide, and ammonium bromide; iodides such as sodium iodide, potassium iodide, and ammonium iodide.

Among the halogen compounds, chlorine compounds, bromine compounds or iodine compounds are preferable. The halogen compounds may be used alone in 1 kind, or in combination of 2 or more kinds. The composition of the present invention may contain or may not contain a halogen compound, but may be used in an amount effective for increasing the rate of formation of a chemical treatment film and the heat resistance of the chemical treatment film, and the amount is typically preferably about 0.001 to 1% by weight, and particularly preferably about 0.01 to 0.1% by weight, based on the total weight of the composition. Within the above range, the addition of the halogen compound can sufficiently improve the rate of formation of the chemically treated film and the heat resistance of the chemically treated film while avoiding the precipitation of the imidazole compound due to the salting-out effect.

(D) Surface treatment method

The surface treatment method of the present invention comprises a method of contacting a material containing copper or a copper alloy with the aqueous composition of the present invention as described above.

Typical examples of the material containing copper or a copper alloy include a circuit of a printed wiring board, a circuit portion of an electronic component such as a package IC, and the like. The kind of the copper alloy is not particularly limited, and examples thereof include copper alloys such as brass, tin bronze, and phosphor bronze.

The composition of the present invention is contacted with the copper or copper alloy material at a temperature and for a time effective to form a chemically treated film. Typically, suitable liquid temperatures for the compositions of the present invention are generally about 10 to 70 deg.C, preferably about 20 to 50 deg.C, and suitable contact times are about 1 second to 10 minutes, preferably about 10 seconds to 5 minutes. The contact method is not particularly limited, and examples thereof include immersion, spraying, and coating. After this contact, the material containing copper or copper alloy is washed with water, dried, and then subjected to a soldering process.

(E) Welding method

The soldering method of the present invention includes a step of bringing a copper or copper alloy-containing material into contact with the aqueous composition of the present invention, and a step of soldering the copper or copper alloy-containing material with a lead-free solder.

The procedure for contacting the aqueous composition is as described above. A chemically treated film is formed on the surface of a copper or copper alloy material by contacting the copper or copper alloy-containing material with the aqueous composition of the present invention and drying.

The soldering of the present invention includes both cases of bonding electronic parts such as discrete parts on a copper through-hole portion of a printed circuit board using, for example, lead-free solder, and bonding electronic parts such as chip parts, packaged ICs, and the like on a surface of a copper pad portion of a printed circuit board using, for example, lead-free solder.

When the electronic components are soldered to the circuit portion of the printed wiring board, the soldering process is performed by a flow soldering method in which the printed wiring board is moved over a solder bath containing a liquid solder melted by heating to solder the electronic components to the bonding portion of the printed wiring board, or a reflow soldering method in which a paste solder is printed on the printed wiring board in advance according to a circuit diagram, the electronic components are mounted thereon, and the printed wiring board is heated together with the solder to melt the solder to solder the printed wiring board.

As the lead-free solder, a known lead-free solder can be used without limitation. Examples of the known lead-free solder include Sn-Ag-Cu-based solder, Sn-Ag-Bi-based solder, Sn-Ag-Bi-In-based solder, Sn-Zn-based solder, and Sn-Cu-based solder. Particularly preferred are Sn-Ag-Cu based lead-free solders.

In addition, after the surface treatment step of the present invention and before the soldering step, a thermoplastic resin film is formed on the chemically treated film formed by the surface treatment to obtain a two-layer film structure, whereby the heat resistance can be further improved.

The thermoplastic resin film may be formed, for example, from a rosin derivative such as rosin or rosin ester; terpene resins, terpene resin derivatives of terpene phenol resins; or, a thermoplastic resin having excellent heat resistance, which is composed of an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, or a mixture thereof, is dissolved in a solvent such as toluene, ethyl acetate, or isopropyl alcohol, and is uniformly applied to the chemical-treated film by a roll coater or the like so that the film thickness after drying is about 1 to 30 μm, thereby forming a two-layer structure of the chemical-treated film and the thermoplastic resin.

Accordingly, at this time, the welding method of the present invention includes: a surface treatment step of bringing a copper or copper alloy-containing material into contact with the aqueous composition of the present invention and forming a chemical treatment film on the surface of the copper or copper alloy-containing material; forming a thermoplastic resin film on the chemically treated film; and a step of welding the copper or copper alloy material after forming the thermoplastic resin film.

Examples

The present invention will be described in detail below by giving examples and test examples, but the present invention is not limited thereto.

First, examples 1-1 to 1-4 for producing 2-phenyl-4- (dichlorophenyl) imidazole compounds will be described. The raw materials used in these examples were obtained as follows.

Raw materials

2 ', 4' -Dichloroacetophenone (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.)

3 ', 4' -Dichloroacetophenone (reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.)

2 ', 4' -Dichloropropiophenone (reagent manufactured by Lancaster Co., Ltd.)

3 ', 4' -Dichloropropiophenone (reagent manufactured by Aldrich Co.)

Benzamidine hydrochloride (reagent manufactured by Tokyo chemical industry Co., Ltd.)

Examples 1 to 1

Synthesis of 2-phenyl-4- (2, 4-dichlorophenyl) imidazole

43.4g (0.272 mol) of bromine was added dropwise to a solution containing 50.5g (0.267 mol) of 2 ', 4' -dichloroacetophenone and 100g of methanol at a reaction temperature of 45 to 50 ℃. After completion of the dropwise addition, methanol was distilled under reduced pressure from the reaction solution, and the obtained concentrate was dissolved in 120g of toluene, washed with water (100 ml. times.3 times), and toluene was distilled off under reduced pressure to obtain 68.0g (0.254 mol) of crude 2-bromo-2 ', 4' -dichloroacetophenone as a brown oil.

A suspension containing 39.8g (0.254 mol) of benzamidine hydrochloride, 13.7g (0.254 mol) of sodium methoxide and 170ml of tetrahydrofuran was heated under reflux for 1 hour, then cooled to 25 ℃ and a solution containing 68.0g (0.254 mol) of the above crude 2-bromo-2 ', 4' -dichloroacetophenone and 120ml of tetrahydrofuran was added dropwise at a reaction temperature of not more than 30 ℃. After completion of the dropwise addition, 13.7g (0.254 mol) of sodium methoxide was added thereto, and the mixture was refluxed for 1 hour. Then, the reaction mixture was cooled to room temperature, insoluble matter was filtered off, the filtrate was dried under reduced pressure, and the dried product taken out was washed with water and successively with toluene, and then dried to obtain 33.8g (crude yield 46.0%) of a crude crystal of the objective product. The crude crystals were recrystallized from acetonitrile to give pale yellow crystals.

Melting points of the obtained crystals, Rf values by thin layer chromatography, NMR and mass spectrum data are as follows.

mp.162-164℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf 0.64

NMR(CD₃OD)：δ6.8-8.0(m)

MS m/z(％)：

290(66)，288(M+，100)，261(3)，253(3)，226(3)，218(3)，199(3)，185(5)，157(3)，150(7)，123(17)，117(13)，114(13)，104(5)，89(15)，77(10)

From these spectral data, it was confirmed that the obtained compound was 2-phenyl-4- (2, 4-dichlorophenyl) imidazole represented by the following structural formula (4).

Examples 1 to 2

Synthesis of 2-phenyl-4- (3, 4-dichlorophenyl) imidazole

43.9g (0.275 mol) of bromine was added dropwise to a solution containing 50.5g (0.267 mol) of 3 ', 4' -dichloroacetophenone and 120g of methanol at a reaction temperature of 50 to 55 ℃. After completion of the dropwise addition, methanol was distilled under reduced pressure from the reaction solution, and the obtained concentrate was dissolved in 120g of toluene, washed with water (150 ml. times.3 times), and the toluene was distilled off under reduced pressure to obtain 68.0g (0.254 mol) of crude 2-bromo-3 ', 4' -dichloroacetophenone as a brown oil.

While a suspension containing 39.8g (0.254 mole) of benzamidine hydrochloride, 102.1g (1.02 mole) of potassium hydrogencarbonate, 400ml of tetrahydrofuran and 100ml of water was heated under reflux, a solution containing 68.0g (0.254 mole) of the above crude 2-bromo-3 ', 4' -dichloroacetophenone and 110ml of tetrahydrofuran was added dropwise over 30 minutes. After the completion of the dropwise addition, the mixture was refluxed for 2 hours. Then, the reaction mixture was dried under reduced pressure, and after washing the dried product with water and successively with toluene, 45.5g (crude yield 62%) of crude crystals of the objective product were obtained. This crude crystal was recrystallized from acetonitrile to obtain a white purified powder.

mp.179-182℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf 0.52

NMR(CD₃OD)：δ7.4-8.0(m)

MS m/z(％)：

290(64)，288(M+，100)，253(4)，226(4)，185(4)，150(12)，123(21)，117(15)，104(6)，89(12)，77(10)

From these spectral data, it was confirmed that the obtained compound was 2-phenyl-4- (3, 4-dichlorophenyl) imidazole represented by the following structural formula (5).

Examples 1 to 3

Synthesis of 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole

51.4g (0.322 mol) of bromine was added dropwise to a solution containing 63.2g (0.311 mol) of 2 ', 4' -dichloropropiophenone and 140g of methanol at a reaction temperature of 50 to 55 ℃. After completion of the dropwise addition, methanol was distilled under reduced pressure from the reaction solution, and the obtained concentrate was dissolved in 120g of toluene, washed with water (150 ml. times.3 times), and toluene was distilled off under reduced pressure to obtain 85.2g (0.302 mol) of crude 2-bromo-2 ', 4' -dichloropropiophenone as a brown oil.

A suspension containing 47.3g (0.302 mol) of benzamidine hydrochloride, 16.3g (0.302 mol) of sodium methoxide and 250ml of tetrahydrofuran was heated under reflux for 1 hour, then cooled to 25 ℃ and a solution containing 85.2g (0.302 mol) of the above crude 2-bromo-2 ', 4' -dichloropropiophenone and 160ml of tetrahydrofuran was added dropwise at a reaction temperature of not more than 30 ℃. After completion of the dropwise addition, 16.3g (0.302 mol) of sodium methoxide was added thereto, and the mixture was refluxed for 1 hour. Then, the reaction mixture was cooled to room temperature, insoluble matter was filtered off, the filtrate was dried under reduced pressure, and the dried product was washed with water, washed successively with toluene and dried to obtain 50.4g (crude yield 55.0%) of a crude crystal of the objective product. The crude crystals were recrystallized from a mixture of acetonitrile and DMF to give colorless purified crystals.

mp.222-224℃

TLC (silica gel, acetone): rf 0.67

NMR(d6-DMSO)：δ2.19(s，3H)，7.2-8.1(m，8H)

MS m/z(％)：

304(65)，302(M+，100)，267(14)，232(4)，198(3)，172(4)，164(11)，130(8)，104(17)，89(15)，77(13)

From these spectral data, it was confirmed that the obtained compound was 2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole represented by the following structural formula (6).

Examples 1 to 4

Synthesis of 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole

51.1g (0.320 mol) of bromine was added dropwise to a solution containing 65.0g (0.320 mol) of 3 ', 4' -dichloropropiophenone and 150g of methanol at a reaction temperature of 58 to 60 ℃. After completion of the dropwise addition, methanol was distilled under reduced pressure from the reaction solution, and the obtained concentrate was dissolved in 130g of toluene, washed with water (150 ml. times.3 times), and toluene was distilled off under reduced pressure to obtain 86.6g (0.307 mol) of crude 2-bromo-3 ', 4' -dichloropropiophenone as a brown oil.

While a suspension containing 48.1g (0.307 mol) of benzamidine hydrochloride, 123.4g (1.23 mol) of potassium hydrogencarbonate, 450ml of tetrahydrofuran and 110ml of water was heated under reflux, a solution containing 86.6g (0.307 mol) of the above crude 2-bromo-3 ', 4' -dichloropropiophenone and 120ml of tetrahydrofuran was added dropwise over 40 minutes. After the completion of the dropwise addition, the mixture was refluxed for 2 hours. Then, the reaction mixture was dried under reduced pressure, and the dried product was washed with water and successively washed with toluene to obtain 65.3g (crude yield: 71.3%) of crude crystals of the objective product. This crude crystal was recrystallized from acetonitrile to obtain a white purified powder.

mp.169-171℃

TLC (silica gel, acetone): rf 0.68

NMR(CD₃OD)：δ2.4(s，3H)，7.2-8.0(m，8H)

MS m/z(％)：

304(69)，302(M+，100)，266(6)，231(6)，198(5)，164(7)，130(6)，104(16)，89(12)，77(12)

From these spectral data, it was confirmed that the obtained compound was 2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole represented by the following structural formula (7).

Examples 2-1 to 2-5 for synthesizing 2- (dichlorophenyl) -4-phenylimidazole compounds will be described below. The raw materials used in these examples were obtained as follows.

Raw materials

2-acetoxyacetophenone (synthesized by the method described in the following reference example)

1-phenyl-1, 2-propanedione (Tokyo chemical industry Co., Ltd., reagent)

2, 3-Dichlorobenzaldehyde (reagent manufactured by Tokyo chemical industry Co., Ltd.)

2, 4-Dichlorobenzaldehyde (reagent manufactured by Tokyo chemical industry Co., Ltd.)

2, 6-Dichlorobenzaldehyde (reagent manufactured by Tokyo chemical industry Co., Ltd.)

3, 4-Dichlorobenzaldehyde (reagent manufactured by Tokyo chemical Co., Ltd.)

Reference example 1

Synthesis of 2-acetoxyacetophenone

78.5g (0.80mol) of potassium acetate, 5.0g (0.08mol) of acetic acid and 123.7g (0.80mol) of 2-chloroacetophenone were heated under reflux in 500ml of ethanol for 6 hours. After the completion of heating, the reaction mixture was cooled to room temperature, and the precipitated potassium chloride was filtered off, and ethanol was distilled off under reduced pressure to obtain a light brown oily substance. This oily substance was poured into 1 liter of water, and the precipitated tan crystalline solid was collected by filtration, followed by recrystallization from methanol to obtain 113.1g (0.635mol, yield 79.3%) of 2-acetoxyacetophenone.

Example 2-1

Synthesis of 2- (2, 3-dichlorophenyl) -4-phenylimidazole

In a solution of 17.8g (0.1mol) of 2-acetoxyacetophenone and 17.5g (0.1mol) of 2, 3-dichlorobenzaldehyde in 120ml of isopropanol, a solution of 43.9g (0.22mol) of copper (II) acetate monohydrate dissolved in 150ml of 25% aqueous ammonia was added repeatedly in small amounts under water cooling, followed by heating to 60 ℃ for 1 hour and further heating to 78 ℃ for 3 hours.

After completion of the reaction, the reaction mixture was cooled to 5 ℃ and the precipitate was collected by filtration, washed with water and dried to obtain 31.1g of a dark green powder. The powder was suspended in 160ml of methanol, and 4.9g (0.06mol) of 70% sodium hydrosulfide was added thereto, followed by heating and refluxing for 1 hour. Then, the methanol solution was cooled, and black insoluble matter was filtered off. Methanol was continuously distilled off from the methanol solution under reduced pressure, the obtained residue was dissolved in chloroform, washed with water, and chloroform was distilled off under reduced pressure, and the obtained residue was recrystallized with acetonitrile to obtain 12.5g of an off-white powdery crystal (yield 43%).

mp.144-146℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf is 0.51

NMR(CDCl₃)：δ7.2-8.4(m)

MS m/z(％)：290(70)，288(M+，100)，253(7)，123(4)，117(9)，89(19)

From these spectral data, it was confirmed that the obtained compound was 2- (2, 3-dichlorophenyl) -4-phenylimidazole represented by the following structural formula (8).

Examples 2 to 2

Synthesis of 2- (2, 4-dichlorophenyl) -4-phenylimidazole

In a solution of 17.8g (0.1mol) of 2-acetoxyacetophenone and 17.5g (0.1mol) of 2, 4-dichlorobenzaldehyde in 150ml of isopropanol, a solution of 43.9g (0.22mol) of copper (II) acetate monohydrate dissolved in 160ml of 25% aqueous ammonia was added repeatedly in small amounts under water cooling, followed by heating to 60 ℃ for 1 hour and further heating to 80 ℃ for 2.5 hours.

After completion of the reaction, the reaction mixture was cooled to 10 ℃ and the precipitate was filtered, washed with water and dried to obtain 27.3g of a dark green powder. This powder was suspended in 150ml of methanol, and 4.3g (0.054mol) of 70% sodium hydrosulfide was added thereto, followed by heating and refluxing for 1 hour. Then, the methanol solution was cooled, and black insoluble matter was filtered off. Methanol was continuously distilled off from the methanol solution under reduced pressure, the obtained residue was dissolved in chloroform, washed with water, and then chloroform was distilled off under reduced pressure, and the obtained residue was recrystallized with acetonitrile to obtain 11.0g of yellow powdery crystals (yield 38%).

mp.153-156℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf is 0.56

NMR(CDCl₃)：δ7.0-8.5(m)

MS m/z(％)：

290(66)，288(M+，100)，253(5)，226(4)，185(5)，171(4)，144(4)，123(7)，117(15)，100(4)，89(19)

From these spectral data, it was confirmed that the obtained compound was 2- (2, 4-dichlorophenyl) -4-phenylimidazole represented by the following structural formula (9).

Examples 2 to 3

Synthesis of 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole

14.8g (0.1mol) of 1-phenyl-1, 2-propanedione, 17.5g (0.1mol) of 2, 3-dichlorobenzaldehyde and 46.2g (0.6mol) of ammonium acetate are heated under reflux in 100ml of acetic acid for 5 hours. After completion of the reaction, the obtained reaction solution was cooled to room temperature, poured into a large amount of dilute ammonia water, and the precipitated solid was filtered, washed with water, and recrystallized using acetonitrile to obtain 17.3g of light green powdery crystals (yield 57%).

mp.183-185℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf 0.60

NMR(CDCl₃)：δ2.5(s，3H)，7.2-8.3(m，8H)

MSm/z(％)：304(69)，302(M+，100)，267(3)，225(2)，172(6)，151(5)，130(35)，103(30)，89(20)，77(19)

From these spectral data, it was confirmed that the obtained compound was 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole represented by the following structural formula (10).

Examples 2 to 4

Synthesis of 2- (2, 6-dichlorophenyl) -4-phenyl-5-methylimidazole

14.8g (0.1mol) of 1-phenyl-1, 2-propanedione, 17.5g (0.1mol) of 2, 6-dichlorobenzaldehyde and 46.2g (0.6mol) of ammonium acetate are heated under reflux in 100ml of acetic acid for 5 hours. After the reaction, the obtained reaction solution was cooled to room temperature, poured into a large amount of dilute ammonia water, and the precipitated solid was filtered, washed with water, and dried to obtain 30.4g of brown solid. The solid was dissolved in 150ml of chloroform, concentrated hydrochloric acid was added, the precipitated hydrochloride was filtered, washed with acetone, dissolved in methanol, and then sodium methoxide methanol solution was added, after desalting, methanol was distilled off under reduced pressure, and the resulting solid was washed with water and dried to obtain 18.5g of milky white powdery crystals (yield 61%).

mp.185-189℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf is 0.49

NMR(CDCl₃)：δ2.5(s，3H)，7.2-7.7(m，8H)

MS m/z(％)：

304(66)，302(M+，100)，267(2)，225(2)，199(2)，172(6)，151(4)，130(39)，103(29)，89(31)，77(19)

From these spectral data, it was confirmed that the obtained compound was 2- (2, 6-dichlorophenyl) -4-phenyl-5-methylimidazole represented by the following structural formula (11).

Examples 2 to 5

Synthesis of 2- (3, 4-dichlorophenyl) -4-phenyl-5-methylimidazole

14.8g (0.1mol) of 1-phenyl-1, 2-propanedione, 17.5g (0.1mol) of 3, 4-dichlorobenzaldehyde and 46.2g (0.6mol) of ammonium acetate are heated under reflux in 100ml of acetic acid for 5 hours. After completion of the reaction, the obtained reaction solution was cooled to room temperature, poured into a large amount of dilute ammonia water, and the precipitated solid was filtered, washed with water, and recrystallized with methanol to obtain 18.8g of pale yellow powdery crystals (yield 62%).

mp.172-175℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf 0.60

NMR(CD₃Cl₃)：δ2.5(s，3H)，7.3-7.9(m，8H)

MS m/z(％)：

304(63)，302(M+，100)，267(3)，225(3)，199(2)，172(7)，151(4)，130(25)，103(20)，89(12)，77(15)

From these spectral data, it was confirmed that the obtained compound was 2- (3, 4-dichlorophenyl) -4-phenyl-5-methylimidazole represented by the following structural formula (12).

Next, a surface treatment agent and a surface treatment composition containing the imidazole compound of the present invention will be described. The synthesis of the imidazole compounds used is shown below.

Imidazole compounds

2- (2, 3-dichlorophenyl) -4-phenylimidazole synthesized in example 2-1 was used.

2- (2, 4-dichlorophenyl) -4-phenylimidazole synthesized in example 2-2 was used.

2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole synthesized in examples 2 to 3 was used.

2- (2, 6-dichlorophenyl) -4-phenyl-5-methylimidazole synthesized in examples 2 to 4 was used.

2- (3, 4-dichlorophenyl) -4-phenyl-5-methylimidazole synthesized in examples 2 to 5 was used.

2-phenyl-4- (2, 4-dichlorophenyl) imidazole synthesized in example 1-1 was used.

2-phenyl-4- (3, 4-dichlorophenyl) imidazole synthesized in example 1-2 was used.

2-phenyl-4- (2, 4-dichlorophenyl) -5-methylimidazole synthesized in examples 1 to 3 was used.

2-phenyl-4- (3, 4-dichlorophenyl) -5-methylimidazole synthesized in examples 1 to 4 was used.

Synthesis of 2- (2, 4-dichlorophenyl) -4-phenyl-5-methylimidazole

14.8g (0.1mol) of 1-phenyl-1, 2-propanedione, 17.5g (0.1mol) of 2, 4-dichlorobenzaldehyde and 46.2g (0.6mol) of ammonium acetate are heated under reflux in 100ml of acetic acid for 5 hours. After completion of the reaction, the obtained reaction solution was cooled to room temperature, poured into a large amount of dilute ammonia water, and the precipitated solid was filtered, washed with water, and recrystallized with methanol to obtain 16.4g of colorless powdery crystals (yield 54%).

mp.143-145℃

TLC (silica gel, chloroform/ethyl acetate 9/1): rf is 0.65

NMR(CDCl₃)：δ2.5(s，3H)，7.3-8.4(m，8H)

MS m/z(％)：

304(69)，302(M+，100)，267(2)，225(2)，199(2)，172(6)，151(4)，130(31)，103(23)，89(17)，77(17)

2, 4-Diphenylimidazole and 2, 4-diphenyl-5-methylimidazole are synthesized by the method described in JP-A-7-243053.

2- (4-chlorophenyl) -4-phenylimidazole, synthesized according to the synthesis methods shown in examples 2-1 and 2-2 of the present specification. Further, as the benzaldehyde compound as a raw material, 4-chlorobenzaldehyde was used.

2- (4-chlorophenyl) -4-phenyl-5-methylimidazole according to the synthetic method shown in examples 2-3 and 2-4 of the present specification. Further, as the benzaldehyde compound as a raw material, 4-chlorobenzaldehyde was used.

2-phenyl-4- (4-chlorophenyl) imidazole, synthesized according to the synthesis methods shown in examples 1-1 and 1-2 of the present specification. In addition, 4' -chloroacetophenone was used as the acetophenone compound as a starting material.

2-phenyl-4- (4-chlorophenyl) -5-methylimidazole according to the synthetic method shown in examples 1-3 and 1-4 of the present specification. In addition, as the propiophenone compound as a raw material, a 4' -chlorophenylacetone compound was used.

The evaluation test methods performed on the surface treatment compositions prepared in examples 3-1 to 3-10 and comparative examples 3-1 to 3-6 described below will be described.

Evaluation test of flux bleeding Property

As a test piece, a 120mm (length) × 150mm (width) × 1.6mm (thickness) glass epoxy resin printed wiring board having 300 copper through holes with an inner diameter of 0.80mm was used. The test piece was degreased with an acid-based cleaning agent, soft-etched with a sulfuric acid/hydrogen peroxide-based reagent, and then washed with water, and then immersed in a surface treatment composition held at a predetermined liquid temperature shown in Table 1, after which, the surface treatment composition was washed with water, dried, and a chemical treatment film having a thickness of about 0.1 to 0.5 μm was formed on the copper surface.

The test piece subjected to the surface treatment was subjected to 3 times of reflow heating at a peak temperature of 240 ℃ by an infrared reflow apparatus (trade name: MULTI-PRO-306, manufactured by Vetronix Co., Ltd.), and then welded by a flow welding apparatus (conveying speed: 1.0 m/min).

The flux used was a tin-lead eutectic flux (trade name: H63A, manufactured by the metal industry) having a composition of 63-37 lead (wt%), and JS-64MSS (spread casting) was used as the flux used for soldering. In addition, the welding temperature was 240 ℃.

The test piece subjected to the surface treatment was soldered using a lead-free solder as in the case of the tin-lead eutectic solder. Further, the flux used was a lead-free flux (trade name: H705 "ECOSOLDER", manufactured by Kikusho metals industries) having a composition of 96.5 tin to 3.0 silver to 0.5 copper (wt%), and the flux used at the time of soldering was JS-E-09 (spread casting). The peak temperature of reflow heating was 245 ℃, and the welding temperature was 245 ℃.

For the test piece subjected to soldering, the number of through holes from which flux rose (was soldered) to the upper pad portion of the copper through hole was measured, and the ratio (%) to the total number of through holes (300) was calculated.

When the wettability of the flux with respect to the copper surface is large, the molten flux penetrates into the copper via hole and easily rises to the upper pad portion of the via hole. That is, when the ratio of the number of through holes rising up to the upper pad portion to the total number of through holes is large, it is judged that the wettability of the flux to copper is good and the solderability is good.

Evaluation test of solder ductility

As a test piece, a glass epoxy resin printed circuit board (as a circuit diagram, circuits each having 10 copper foils, a conductor width of 0.8mm and a length of 20mm, and formed at a distance of 1.0mm in the width direction) of 50mm (length) × 50mm (width) × 1.2mm (thickness) was used. The test piece was degreased with an acid-based cleaning agent, soft-etched with a sulfuric acid/hydrogen peroxide-based reagent, further washed with water, and then immersed in a surface treatment agent held at a predetermined liquid temperature shown in table 1, for a predetermined time shown in table 1, and then washed with water and dried, thereby forming a chemical treatment film having a thickness of about 0.10 to 0.50 μm on the copper surface.

The test piece subjected to the surface treatment was heated by 1 reflow at a peak temperature of 240 ℃ using an infrared reflow apparatus (trade name: MULTI-PRO-306, manufactured by Vetronix Co., Ltd.). Then, a tin-lead paste solder was printed on the center of the copper circuit portion by using a metal mask having an aperture of 1.2mm and a thickness of 150 μm, and reflow-heated under the previous conditions to perform soldering. The tin-lead paste flux used was eutectic flux (trade name: OZ-63-330F-40-10, manufactured by Kikusan metals industries) having a composition containing 63% by weight of tin-37% by weight of lead.

The test piece subjected to the surface treatment was soldered using a lead-free paste solder as in the case of the tin-lead paste solder. The lead-free solder paste used was a lead-free solder having a composition of 96.5 tin-3.0 silver-0.5 copper (wt%) (trade name: M705-221BM5-42-11, manufactured by Kikusan Metal industries). The peak temperature was set to 245 ℃ by reflow heating performed before and after printing of the paste flux.

The length (mm) of the solder after wet spreading on the copper circuit portion was measured with respect to the obtained test piece.

When the length is large, the wettability of the flux is considered to be good, and the weldability is considered to be good.

Example 3-1

A surface treatment composition was prepared by dissolving 2- (2, 3-dichlorophenyl) -4-phenyl-5-methylimidazole as an imidazole compound, acetic acid as an acid, copper acetate as a metal salt, and ammonium bromide as a halogen compound in deionized water according to the composition shown in table 1 below, and adjusting the ph to 3.1 with ammonia water.

Then, the test piece of the printed wiring board was immersed in the surface treatment agent adjusted to 40 ℃ for 60 seconds, washed with water, dried, and measured for flux overflow and ductility of the paste flux.

Examples 3-2 to 3-10 and comparative examples 1 to 6

Surface treatment compositions having the compositions shown in Table 1 were prepared in the same manner as in example 3-1. Then, after surface treatment under the treatment conditions described in table 1, the flux was washed with water, dried, and the flux overflow property and the ductility of the paste flux were measured.

The test results of the compositions of examples 3-1 to 3-10 and comparative examples 1 to 6 are shown in Table 1.

The test results shown in Table 1 are described below. The imidazole compound used in the present invention has a basic skeleton of a 2, 4-diphenylimidazole compound, and hydrogen atoms of phenyl groups bonded to the 2-position or 4-position of the imidazole skeleton are substituted with 2 chlorine atoms, as shown in examples 3-1 to 3-10. The imidazole compound used in the comparative example was an imidazole compound in which the phenyl group was not substituted with a chlorine atom, or an imidazole compound substituted with 1 chlorine atom.

Table 1 shows that the flux overflow property when soldering is performed using the tin-lead eutectic solder is 90 to 100% in the test results of the examples and the comparative examples, and almost no difference is observed between the examples and the comparative examples.

However, the flux overflow property when the lead-free flux is used is 90 to 100% in the example, but about 30 to 60% remains in the comparative example. As a result, when soldering is performed using a lead-free solder, the solder wettability is significantly improved by treating the copper surface with the surface treatment composition of the present invention.

Further, regarding the solder ductility when the tin-lead eutectic solder is used, the solder ductility is about 2.9 to 4.0mm in the examples, and about 2.9 to 3.7mm in the comparative examples, and it can be seen that the examples are slightly superior to the comparative examples. However, the lead-free solder used is about 1.6 to 1.7mm, while the lead-free solder used in the comparative example is about 1.5 to 1.6 mm. As a result, when soldering is performed using a lead-free solder, the solder wettability is significantly improved by treating the copper surface with the surface treatment composition of the present invention.

This effect is considered to be due to the imidazole compound used in the composition for surface treatment of the present invention having the basic skeleton of the 2, 4-diphenylimidazole compound and being an imidazole compound in which the phenyl group bonded at the 2-position or 4-position is substituted with 2 chlorine atoms.

Industrial applicability

The imidazole compound of the present invention is suitably used as a component of an aqueous composition for surface treatment of copper or a copper alloy when an electronic part is soldered to a circuit part containing copper or a copper alloy on a printed wiring board using a lead-free solder.

Claims

1. A welding method is characterized in that,

comprising the step of contacting a copper or copper alloy-containing material with an aqueous composition, and

a step of soldering a material containing copper or a copper alloy using a lead-free solder,

the composition contains an imidazole compound represented by the general formula (1),

in the formula, R¹Represents a hydrogen atom or a methyl group; and R is²And R³Represents a chlorine atom, and R⁴And R⁵Represents a hydrogen atom; or R²And R³Represents a hydrogen atom, and R⁴And R⁵Represents a chlorine atom.

2. Welding method according to claim 1,

the composition also contains an acid.

3. Use of an aqueous treating agent comprising a compound represented by the following general formula (1) as a surface treating agent for copper or a copper alloy for soldering using a lead-free solder,