JPH08183778A - Surface-protecting agent of metal and production using the same - Google Patents

Abstract

PURPOSE: To obtain a compound which is a specific imidazole derivative, has the forming property of film excellent in rest-proofing property, moisture resistance, heat resistance and chemical resistance, has good wettability and spreading property of low-melting point cream colder and useful as a water-soluble protecting agent, etc., of the metal surface of a printed-wiring board. CONSTITUTION: This compound is expressed by the formula [R1 , R3 and R4 are each H, a lower alkyl or a halogen; R2 is a (branched)alkylene; a, e and f are each 0-4; c and d is 0 or 1; b is 0-10], e.g. 2-(2-phenoxyethyl)benzimidazole. The metal surface protecting agent is obtained by adding a compound of the formula to an organic acid such as acetic acid or oxalic acid and a metal compound such as zinc acetate, bringing the compound into contact with an aqueous solution containing a substance having a buffer action of ammonia water to solubilize or emulsify the compound of the formula.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble protective agent for forming a chemical conversion film on a metal surface, and particularly to a metal surface of a printed wiring board having rust-preventing property, heat resistance and moisture resistance.
It is suitable as a protective agent for forming a chemical conversion film having excellent chemical resistance.

[0002]

2. Description of the Related Art As a surface treatment method for forming a chemical conversion film on a metal surface of a printed wiring board, alkylimidazole preflux, 5-methylbenzimidazole preflux, 2-mercaptobenzimidazole preflux, 2-alkyl are used. The publication describes a treatment method using a benzimidazole-based preflux, a 2-phenylimidazole-based preflux, a 2-phenylalkylbenzimidazole-based preflux, and a 2-alkylphenylbenzimidazole-based preflux.

[0003]

In recent years, the surface mounting method has been widely adopted as a method for soldering electronic components to a printed wiring board. Due to this surface mounting method, reflow of low melting point cream solder for temporary fixing of electronic parts, the printed wiring board is exposed to high temperatures frequently, and the heat resistance of the pre-flux used to maintain the solderability of the printed wiring board. Of the low melting point cream solder after the printed wiring board is exposed to a high temperature, the wettability, spreadability and solderability of the low melting point solder paste are required to be excellent in the performance of the preflux. However, the above-mentioned pre-flux treatment has a drawback that soldering is hindered when the chemical conversion film is exposed to high temperatures. Therefore, there is a strong demand for the development of a stable water-soluble preflux having excellent wettability and solderability of cream solder even after being exposed to high temperatures.

[0004]

The present inventor has conducted extensive studies in view of such circumstances, and as a result, by bringing a metal surface into contact with an aqueous solution containing the compound represented by Chemical formula 1 as an active ingredient, It was found that a chemical conversion film having excellent rust resistance, heat resistance, moisture resistance and chemical resistance was formed, and the present invention was completed. Typical compounds represented by Chemical formula 1 used in the practice of the present invention are 2- (1-phenoxymethyl) benzimidazole, 2- (2-phenoxyethyl) benzimidazole, 2- (1-phenoxyethyl) benzimidazole, 2- (1-phenoxypropyl) benzimidazole, 2- (10-phenoxydecyl) benzimidazole, 2- (2-methoxyphenyl) benzimidazole, 2- (3-methoxyphenyl) benzimidazole, 2- (4-methoxy) Phenyl) benzimidazole, 2- (2-ethoxyphenyl) benzimidazole, 2- (4-ethoxyphenyl) benzimidazole, 2- (4-butoxyphenyl) benzimidazole, 2- (2-methoxyphenylmethyl) benzimidazole, 2- (3-methoxyphen Nirumechiru) benzimidazole, 2- (4-methoxyphenyl methyl) benzimidazole, 2- (4-ethoxyphenyl-methyl) benzimidazole, 2- (4-
Dodecyloxyphenyl) benzimidazole, 2- [2
-(2-Methoxyphenyl) ethyl] benzimidazole, 2- [2- (4-methoxyphenyl) ethyl] benzimidazole, 2- [3- (4-methoxyphenyl)
Propyl] benzimidazole, 2- (2,3-dimethoxyphenyl) benzimidazole, 2- (2,4-dimethoxyphenyl) benzimidazole, 2- (2,5
-Dimethoxyphenyl) benzimidazole, 2-
(2,6-dimethoxyphenyl) benzimidazole,
2- (3,4-dimethoxyphenyl) benzimidazole, 2- (3,5-dimethoxyphenyl) benzimidazole, 2- (3,4-ethoxyphenyl) benzimidazole, 2- (4-chlorophenoxymethyl) benzimidazole , 2- [3- (2-methyl-4-chlorophenoxy) propyl] benzimidazole, 2- [1-
(2-Methyl-4-chlorophenoxy) ethyl] benzimidazole, 2- (2,3-dichlorophenoxymethyl) benzimidazole, 2- (2,4-dichlorophenoxymethyl) benzimidazole, 2- (3,4- Dichlorophenoxymethyl) benzimidazole, 2-
(2-methoxy-4-chlorophenyl) benzimidazole, 2- (2-methoxy-5-chlorophenyl) benzimidazole, 2- (1-phenoxymethyl) methylbenzimidazole, 2- (2-phenoxyethyl) methylbenzimidazole, 2- (1-phenoxyethyl) methylbenzimidazole, 2- (1-phenoxypropyl) methylbenzimidazole, 2- (10-phenoxydecyl) methylbenzimidazole, 2- (2
-Methoxyphenyl) methylbenzimidazole, 2-
(3-methoxyphenyl) methylbenzimidazole,
2- (4-methoxyphenyl) methylbenzimidazole, 2- (2-ethoxyphenyl) methylbenzimidazole, 2- (4-ethoxyphenyl) methylbenzimidazole, 2- (4-butoxyphenyl) methylbenzimidazole, 2- (2-methoxyphenylmethyl)
Methylbenzimidazole, 2- (3-methoxyphenylmethyl) methylbenzimidazole, 2- (4-methoxyphenylmethyl) methylbenzimidazole, 2-
(4-Ethoxyphenylmethyl) methylbenzimidazole, 2- (4-dodecyloxyphenyl) methylbenzimidazole, 2- [2- (2-methoxyphenyl) ethyl] methylbenzimidazole, 2- [2- (4- Methoxyphenyl) ethyl] methylbenzimidazole,
2- [3- (4-methoxyphenyl) propyl] methylbenzimidazole, 2- (2,3-dimethoxyphenyl) methylbenzimidazole, 2- (2,4-dimethoxyphenyl) methylbenzimidazole, 2- (2,2
5-dimethoxyphenyl) methylbenzimidazole,
2- (2,6-dimethoxyphenyl) methylbenzimidazole, 2- (3,4-dimethoxyphenyl) methylbenzimidazole, 2- (3,5-dimethoxyphenyl) methylbenzimidazole, 2- (3,4-ethoxy) Phenyl) methylbenzimidazole, 2- (4-chlorophenoxymethyl) methylbenzimidazole, 2
-[3- (2-Methyl-4-chlorophenoxy) propyl] methylbenzimidazole, 2- [1- (2-methyl-4-chlorophenoxy) ethyl] methylbenzimidazole, 2- (2,3-dichlorophenoxy) Methyl)
Methylbenzimidazole, 2- (2,4-dichlorophenoxymethyl) methylbenzimidazole, 2-
(3,4-Dichlorophenoxymethyl) methylbenzimidazole, 2- (2-methoxy-4-chlorophenyl) methylbenzimidazole, 2- (2-methoxy-)
5-chlorophenyl) methylbenzimidazole and the like. The use of the compound represented by Chemical Formula 1 of the present invention is not particularly limited, but it is useful as a metal surface protective agent, a curing agent for epoxy resins, a dyeing assistant, an organic synthetic intermediate, and the like. When the compound represented by Chemical formula 1 of the present invention is used as a metal surface protective agent, the organic acid used for solubilizing or emulsifying the compound represented by Chemical formula 1 includes acetic acid, iodoacetic acid, bromoacetic acid, Dimethyl acetic acid, diethyl acetic acid, α
-Bromoacetic acid, chloroacetic acid, dichloroacetic acid, paranitrobenzoic acid, paratoluenesulfonic acid, picric acid, oxalic acid, formic acid, succinic acid, maleic acid, acrylic acid, fumaric acid, tartaric acid, malic acid, adipic acid, lactic acid, oleic acid , Citric acid, metasulfonic acid, sulfamic acid, and the like, and inorganic acids include hydrochloric acid, sulfuric acid, phosphorous acid, phosphoric acid, and the like. Examples of the halogenated aromatic carboxylic acid include 3-bromo-4methylbenzoic acid, 4- (bromomethyl) phenylacetic acid, α-bromophenylacetic acid, α-bromotetradecanoic acid, 2-bromophenylacetic acid, 3-bromophenylacetic acid, 4-bromophenylacetic acid and the like. Examples of the halogenated fatty acid include bromoacetic acid, 3-bromo-2- (bromomethyl) propionic acid, 2-bromobutanoic acid, 4-bromobutanoic acid, 2-bromohexadecanoic acid, 2-bromohexanoic acid, 2-bromo-3-methylbutane. Acid, 2-bromo-2-methylpropionic acid, 2-bromooctanoic acid, 8
-Bromooctanoic acid, 2-bromopropionic acid, 3-bromopropionic acid, 2-bromopentanoic acid, 5-bromopentanoic acid, chloroacetic acid, chlorobutyric acid, chloropropionic acid and the like. The metal ions include lithium, beryllium, potassium, magnesium, zinc acetate, zinc formate,
Zinc lactate, zinc citrate, zinc benzoate, zinc oxalate, zinc hydroxide, zinc bromide, zinc phosphate, zinc oxide, zinc chloride, lead acetate, lead hydroxide, lead bromide, lead iodide, lead oxalate, Lead borate, ferrous chloride, ferric chloride, cuprous bromide, cupric bromide, cuprous iodide, copper formate, nickel chloride, nickel acetate, cuprous chloride, cupric chloride, Metal compounds such as cuprous oxide, cupric oxide, copper hydroxide, copper phosphate, copper carbonate, copper acetate, and copper sulfate. At least one selected from any of the above groups and one or two compounds represented by Chemical formula 1
Used as an aqueous solution that is a mixture of more than one type. It should be noted that adding a substance having a buffering action such as aqueous ammonia or amines to the treatment liquid is effective not only for enhancing the stability of PH of the aqueous solution but also for accelerating the film formation rate. In addition, various additives which have been conventionally used as surface treatment agents and the like may be added as necessary. In the practice of the present invention, when it becomes difficult to dissolve the compound represented by Chemical formula 1, organic acid, metal compound, halogenated aromatic carboxylic acid, and halogenated fatty acid, methanol, ethanol, isopropyl alcohol, butanol, acetone Water-soluble solvents such as the above can be used alone, respectively, and can also be used by mixing them at an arbitrary ratio. It is also effective to add a surfactant and an emulsifying dispersant. By bringing into contact with an aqueous solution containing the compound represented by Chemical formula 1, an organic acid, and a metal compound used in the practice of the method of the present invention, the chemical conversion film has rust prevention, heat resistance, and chemical resistance,
Solder wettability and solder spreadability can be further enhanced. It is also possible to improve the heat resistance by applying a thermoplastic resin after forming the chemical conversion film. Rust-preventive conversion coating by the metal surface protective agent of the present invention,
To apply a chemical resistant chemical conversion coating to a metal surface, the metal and the treatment liquid are contacted. As a method of contacting, dipping, spraying,
A coating method is used. The temperature of the treatment liquid to be contacted is
It is suitable that the immersion time is in the range of 0 to 100 ° C. for several seconds to several tens of minutes.

[0005]

According to the above processing method, a metal such as copper,
On the surface of copper alloy, solder, electroless solder, nickel, silver, zinc, etc., effective rust-preventive and chemical-resistant chemical conversion coatings mainly consisting of chemical formula 1 are formed. These chemical conversion coatings are water-repellent, have excellent moisture resistance, heat resistance, and chemical resistance, and protect the metal surface for a long period of time, as well as the wettability, spreadability, solder rise after reflow, and wettability of low melting point cream solder. It is good. In addition, it is possible to manufacture a printed wiring board excellent in terms of work environment and safety.

[0006]

Example 1 Compounds represented by the chemical formula 1 in Table 1 were added to
Ammonia water was added to an aqueous solution containing 5 wt%, formic acid, diethyl acetic acid, cupric bromide, ion-exchanged water, etc. to make pH-adjusted aqueous solutions, which were put in 100 ml containers and the liquid temperature was set to 40 ° C. Heated. On the other hand, 1 cm x 5 cm x
A sample piece of a 0.3 mm copper plate and a 1 cm × 5 cm × 0.3 mm nickel plate was prepared, and then the surface was washed to prepare each type of 0.1% containing the compound represented by the above chemical formula 1 as an active ingredient.
It was immersed in a 5 wt% aqueous solution for 60 seconds. Then, after washing with water, the sample pieces of (1) to
After being heated for 5 minutes, the sample was immersed in post flux and the wetting time was measured using a solder wettability tester. Moisture resistance (MIL-STD-202F-M-106
D) The treated test piece was dipped in post flux and the wetting time was measured using a solder wettability tester. (3) Each type of compound containing the compound represented by the above chemical formula 1 as an active ingredient.
The stability of the liquid was confirmed by putting the 5 wt% aqueous solution in a refrigerator at 5 ° C. for 10 days. The above test results are shown in Table 1.

[Table 1]

[0007]

Example 2 The compound represented by the chemical formula 1 in Table 1 was added to
Ammonia water is added to an aqueous solution containing 5 wt% of formic acid, diethyl acetic acid, cupric bromide, isopropyl alcohol, ion-exchanged water, etc. to prepare pH-adjusted aqueous solutions of various types,
The mixture was placed in a 100 ml container and the liquid temperature was heated to 40 ° C. On the other hand, 1 cm x 5 cm x 0.3 mm copper plate, 1 cm x
A sample piece of a nickel plate of 5 cm × 0.3 mm was prepared, and then the surface was washed and immersed for 60 seconds in each kind of 0.5 wt% aqueous solution containing the compound represented by the above chemical formula 1 as an active ingredient. Then, after washing with water, the sample pieces (1) to (1) were placed in a hot air dryer, heated at 250 ° C. for 5 minutes, immersed in post flux, and the wetting time was measured using a solder wettability tester. Moisture resistance (MIL-STD-
202F-M-106D) The test piece after the treatment was immersed in post flux and the wetting time was measured using a solder wettability tester. (3) Each type of 0.5 wt% aqueous solution containing the compound represented by Chemical Formula 1 as an active ingredient was placed in a refrigerator at 5 ° C. for 10 days to confirm the stability of the solution. The above test results are shown in Table 1.

[0008]

Comparative Example 1 2-phenyl-4-benzyl-5-methylimidazole 0.40 wt%, acetic acid 2.0 wt%, cupric acetate 0.05 wt% and ammonium bromide 0.02
Make an aqueous solution containing 5wt%, put it in a 100ml container,
The liquid temperature was heated to 50 ° C. On the other hand, 1 cm x 5 cm x
A sample piece of a 0.3 mm copper plate and a 1 cm × 5 cm × 0.3 mm nickel plate was prepared, and then the surface was washed and immersed in an aqueous solution for 60 seconds. After that, after washing with water, (1)
The sample pieces (1) to (4) were placed in a hot air dryer, heated at 250 ° C. for 5 minutes, immersed in post flux, and the wetting time was measured using a solder wettability tester. The test pieces after the moisture resistance (MIL-STD-202F-M-106D) treatment of the sample pieces of (2) to (4) were immersed in post flux and the wetting time was measured using a solder wettability tester. (3) The above aqueous solution was placed in a refrigerator at 5 ° C for 10 days to confirm the stability of the solution.
The above test results are shown in Table 1.

[0009]

COMPARATIVE EXAMPLE 2 2-Phenyl-imidazole 1.0 wt
%, Acetic acid 2.0 wt%, cupric chloride 0.05 wt% and ammonium bromide were prepared, put into a 100 ml container and heated to 50 ° C. On the other hand, 1 cm
× 5 cm × 0.3 mm copper plate, 1 cm × 5 cm × 0.
A sample piece of a 3 mm nickel plate was prepared, and then the surface was washed and immersed in the aqueous solution for 60 seconds. Then, after washing with water, the sample pieces of (1) to
After being heated for 5 minutes, the sample was immersed in post flux and the wetting time was measured using a solder wettability tester. Moisture resistance (MIL-STD-202F-M-106
D) The treated test piece was dipped in post flux and the wetting time was measured using a solder wettability tester. (3) The above aqueous solution was placed in a refrigerator at 5 ° C for 10 days to confirm the stability of the solution. The above test results are shown in Table 1.

[0010]

Comparative Example 3 2-Phenyl-benzimidazole 1.0
wt%, acetic acid 2.5 wt%, cupric chloride 0.05 wt%
And make an aqueous solution containing ammonium bromide, 100m
The mixture was placed in a 1-liter container and heated to 50 ° C. On the other hand, 1
cm x 5 cm x 0.3 mm copper plate, 1 cm x 5 cm x
A sample piece of a 0.3 mm nickel plate was prepared, and then the surface was washed and immersed in the aqueous solution for 60 seconds. Then, after washing with water, the sample pieces of (1) to
After heating at 0 ° C. for 5 minutes, it was immersed in post flux and the wetting time was measured using a solder wettability tester. (2) ~
Moisture resistance (MIL-STD-202F-M-10
6D) The treated test piece was immersed in post flux and the wetting time was measured using a solder wettability tester. (3)
The above aqueous solution was placed in a refrigerator at 5 ° C. for 10 days to confirm the stability of the solution. The above test results are shown in Table 1.

[0011]

[Comparative Example 4] 2-p-undecylphenylbenzimidazole 1.0 wt%, glacial acetic acid 6.0 wt%, cupric chloride 0.05 wt%, isopropanol 40 wt%, an aqueous solution containing ion-exchanged water was prepared, and a 100 ml container was prepared. And heated to 50 ° C. On the other hand, 1 cm x 5 cm x
A sample piece of a 0.3 mm copper plate and a 1 cm × 5 cm × 0.3 mm nickel plate was prepared, and then the surface was washed and immersed in an aqueous solution for 60 seconds. After that, after washing with water, (1)
The sample pieces (1) to (4) were placed in a hot air dryer, heated at 250 ° C. for 5 minutes, immersed in post flux, and the wetting time was measured using a solder wettability tester. The test pieces after the moisture resistance (MIL-STD-202F-M-106D) treatment of the sample pieces of (2) to (4) were immersed in post flux and the wetting time was measured using a solder wettability tester. (3) The above aqueous solution was placed in a refrigerator at 5 ° C for 10 days to confirm the stability of the solution.
The above test results are shown in Table 1.

[0012]

The compound of the present invention is soaked in a very stable aqueous solution to form a chemical conversion coating film having excellent rust resistance, moisture resistance, heat resistance and chemical resistance on the metal surface for a long period of time. Especially for surface mounting of a printed wiring board that is not only protected, but also has good wettability and spreadability of low melting point cream solder, solderability after reflow, good wettability, and excellent work environment and safety. It is possible to exert a remarkable effect.

Claims (5)

[Claims] 1. A compound represented by the formula: 2. A surface protecting agent for metals, comprising the compound represented by Chemical formula 1 as an active ingredient. 3. A metal surface protective agent, which comprises contacting with an aqueous solution containing a compound represented by Chemical formula 1, an organic acid, and a metal compound, and a method of using the same. 4. A method for producing a printed wiring board, which comprises applying a soldering treatment after applying a metal surface protective agent. 5. An infrared reflow, a near infrared reflow, a far infrared reflow in which the metal surface protective agent represented by Chemical formula 1 is applied to a metal surface and then heated in air or a nitrogen atmosphere.
A method for manufacturing a printed wiring board, which comprises performing a nitrogen reflow process and a vapor reflow process.