KR20230141969A - Water-soluble preflux, and surface treating method - Google Patents

Abstract

Contains (A) an imidazole compound, (B) an amine compound, (C) an organic acid, and (D) water, wherein the component (B) is (B1) a hindered amine compound, and (B2) a hindered amine compound having 10 or more carbon atoms. A water-soluble preflux containing at least one selected from the group consisting of amine compounds having an alkyl group.

Description

Water-soluble preflux, and surface treatment method {WATER-SOLUBLE PREFLUX, AND SURFACE TREATING METHOD}

The present invention relates to water-soluble prefluxes and surface treatment methods.

Printed wiring boards are often distributed with a solder resist film formed on them. In this case, most of the printed wiring board is covered with a solder resist film. However, since electronic components are mounted, there is no solder resist film on the electrode terminal (land). Therefore, when distributing or storing a printed wiring board, the surface of the electrode terminal is likely to be oxidized. Therefore, in order to prevent oxidation of the surface of the electrode terminal of the printed wiring board, gold plating treatment is sometimes applied to the surface of the electrode terminal. However, gold plating has the problem of increased costs because precious metals are used. Therefore, in printed wiring boards, instead of gold plating treatment, a method of forming an organic film on the surface of the electrode terminal using a water-soluble preflux is adopted (for example, Document 1 (Japanese Patent Laid-Open No. 6-322551) report)).

However, printed wiring boards are reflowed multiple times for soldering of electronic components, and are exposed to high temperatures each time. And, since the organic film deteriorates due to such multiple reflow treatments, there is a risk that the solderability of the electronic component may deteriorate. Therefore, an organic film with better heat resistance is required.

The purpose of the present invention is to provide a water-soluble preflux capable of forming an organic film with good heat resistance, and a surface treatment method.

According to one aspect of the present invention, it contains (A) an imidazole compound, (B) an amine compound, (C) an organic acid, and (D) water, and the component (B) is (B1) a hindered amine compound. , and (B2) an amine compound having an alkyl group having 10 or more carbon atoms.

According to one aspect of the present invention, there is provided a surface treatment method comprising a step of forming an organic film on an electrode terminal of an electronic board using the water-soluble preflux according to the above-mentioned aspect of the present invention.

According to one aspect of the present invention, a water-soluble preflux capable of forming an organic film with good heat resistance and a surface treatment method can be provided.

[Water-soluble preflux]

First, the water-soluble preflux composition according to this embodiment will be described. The water-soluble preflux according to the present embodiment contains (A) an imidazole compound, (B) an amine compound, (C) an organic acid, and (D) water described below. Additionally, the component (B) must contain at least one selected from the group consisting of (B1) a hindered amine compound and (B2) an amine compound having an alkyl group having 10 or more carbon atoms.

The reason why the water-soluble preflux composition according to the present embodiment can form an organic film with good heat resistance is not necessarily clear, but the present inventors speculate as follows.

That is, the organic film in the water-soluble preflux is usually formed by (A) an imidazole compound. In contrast, in this embodiment, it is assumed that (B1) a hindered amine compound or (B2) an amine compound having an alkyl group having 10 or more carbon atoms forms a part of the organic film. It is presumed that these components (B1) or (B2) provide an additional antioxidant effect to the organic film.

[(A) component]

Examples of the (A) imidazole compound used in this embodiment include imidazole and benzoimidazole. These may be used individually or in combination of two or more types.

Examples of imidazole include 2-pentylimidazole, 2-undecyl-4-methylimidazole, 2,4-dimethylimidazole, 2-phenylimidazole, 2-toluylimidazole, 2- Phenyl-4-methylimidazole, 2-phenyl-4-benzylimidazole, 2-phenyl-4-methyl-5-benzylimidazole, 2,4-diphenylimidazole, 2,4,5 -triphenylimidazole, 2-benzylimidazole, 2-benzyl-4-methylimidazole, 2-phenylethylimidazole, 2-(2-phenylethyl)imidazole, and 2-(2- Phenylpentyl)imidazole, etc. can be mentioned.

As benzoimidazoles, 2-propylbenzimidazole, 2-pentylbenzimidazole, 2-octylbenzimidazole, 2-nonylbenzimidazole, 2-hexyl-5-methylbenzimidazole, 2-(2- Methylpropyl)benzoimidazole, 2-(1-ethylpropyl)benzoimidazole, 2-(1-ethylpentyl)benzoimidazole, 2-cyclohexylbenzimidazole, 2-(2-cyclohexylethyl)benzoimidazole Dazole, 2-(5-cyclohexylpentyl)benzoimidazole, 2-phenylbenzoimidazole, 2-phenyl-5-methylbenzoimidazole, 2-benzylbenzimidazole, 2-(2-phenylethyl)benzoimidazole Dazole, 2-(5-phenylpentyl)benzoimidazole, 2-(3-phenylpropyl)-5-methylbenzoimidazole, 2-(4-chlorobenzyl)benzoimidazole, 2-(3,4-dichloro) Benzyl)benzoimidazole, 2-(2,4-dichlorobenzyl)benzoimidazole, 2-(mercaptomethyl)benzoimidazole, 2-(2-aminoethyl)benzoimidazole, 2,2'-ethylenedi Benzoimidazole, 2-(1-naphthylmethyl)benzoimidazole, 2-(2-pyridyl)benzoimidazole, 2-(2-phenylvinyl)benzoimidazole, 2-(phenoxymethyl)benzoimidazole Dazole, 2-[(4-methylphenyl)methyl]-1H-benzoimidazole, 2-[(4-chlorophenyl)methyl]-1H-benzoimidazole, and 2-(phenoxymethyl)-5-methylbenzo Imidazole, etc. can be mentioned.

The amount of component (A) mixed is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, based on 100% by mass of the water-soluble preflux. When the compounding amount of component (A) is more than the above lower limit, it is possible to more easily form an organic film such as a rust-prevention film. Moreover, if the compounding amount of component (A) is below the above upper limit, insoluble matter does not increase, and it is economically preferable.

[(B) Ingredient]

The amine compound (B) used in this embodiment must contain at least one selected from the group consisting of (B1) a hindered amine compound and (B2) an amine compound having an alkyl group having 10 or more carbon atoms. The reflow heat resistance of the organic film can be improved by these components (B1) or (B2). These may be used individually or in combination of two or more types.

The component (B1) has a structure represented by the following general formula (B1).

In general formula (B1), R ¹ is independently a methyl group or an ethyl group, and is preferably a methyl group.

X is hydrogen, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. In addition, when X is hydrogen, it has a structure represented by the following general formula (B1-1). When X is an alkyl group having 1 to 12 carbon atoms, it has a structure represented by the following general formula (B1-2). When X is an alkoxy group having 1 to 12 carbon atoms, it has a structure represented by the following general formula (B1-3).

In addition, in component (B1), the structure of the part before the broken line is not particularly limited.

(B1) The number of structures represented by general formula (B1) in one molecule of component is preferably 1 to 10, and more preferably 2 to 4.

In general formula (B1-1), R ¹ is independently a methyl group or an ethyl group, and is preferably a methyl group.

Compounds having a structure represented by general formula (B1-1) include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, tetrakis(2,2,6,6-tetra Examples include methyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate.

In general formula (B1-2), R ¹ is independently a methyl group or an ethyl group, and is preferably a methyl group.

R ² is an alkyl group with 1 to 12 carbon atoms, preferably an alkyl group with 1 to 8 carbon atoms, more preferably an alkyl group with 1 to 3 carbon atoms, and particularly preferably a methyl group.

Examples of compounds having a structure represented by general formula (B1-2) include bis(1,2,2,6,6-pentamethyl-4-piperidyl)-[[3,5-bis(1,1- Dimethylethyl)-4-hydroxyphenyl]ethyl]butylmalonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-(methyl)-8-(1 ,2,2,6,6-pentamethyl-4-piperidyl)sebacate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3 , 4-tetracarboxylate, and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate.

In general formula (B1-3), R ¹ is independently a methyl group or an ethyl group, and is preferably a methyl group.

R ³ is an alkyl group with 1 to 12 carbon atoms, preferably an alkyl group with 4 to 11 carbon atoms, more preferably an alkyl group with 8 to 11 carbon atoms, and particularly preferably an octyl group or an undecyl group.

Compounds having a structure represented by general formula (B1-3) include bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, and bis(1-undeca). Oxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, etc. are mentioned.

The amount of component (B1) mixed is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 5% by mass or less, and 0.5% by mass or more and 2% by mass or less, based on 100% by mass of the water-soluble preflux. Particularly desirable. If the compounding amount of component (B1) is more than the above lower limit, the heat resistance of the organic film formed can be further improved. In addition, it is preferable that the amount of component (B1) is less than the above upper limit because it is difficult for the amount of component (B1) to become excessive during continuous use of the water-soluble preflux.

From the same viewpoint, the mass ratio ((B1)/(A)) of component (B1) to component (A) is preferably 1/5 or more and 5/1 or less, and more preferably 1/2 or more and 4/1 or less. And, it is particularly preferable that it is 1/1 or more and 3/1 or less.

Component (B2) is an amine compound having an alkyl group having 10 or more carbon atoms.

Examples of alkyl groups having 10 or more carbon atoms include decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, and icosyl group. Among these, decyl group or dodecyl group is preferable.

In one molecule of the amine compound, there may be at least one alkyl group having 10 or more carbon atoms, two may be present, or three may be present.

The amine compound may be a primary amine, a secondary amine, or a tertiary amine.

(B2) Components include decylamine, dodecylamine, N,N-dimethyldecylamine, and N,N-dimethyldodecylamine.

The amount of component (B2) mixed is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.2% by mass or more and 5% by mass or less, and 0.3% by mass or more and 2% by mass or less, based on 100% by mass of the water-soluble preflux. Particularly desirable. (B2) If the compounding amount of component is more than the above lower limit, the heat resistance of the organic film formed can be further improved. In addition, it is preferable that the amount of component (B2) is less than the above upper limit because it is difficult for the amount of component (B2) to become excessive during continuous use of the water-soluble preflux.

From the same viewpoint, the mass ratio ((B2)/(A)) of component (B2) to component (A) is preferably 1/5 or more and 5/1 or less, and more preferably 1/2 or more and 4/1 or less. And, it is particularly preferable that it is 1/1 or more and 3/1 or less.

Component (B) may further contain other amine compounds (hereinafter also referred to as component (B3)) in addition to component (B1) and component (B2), within the range that can achieve the object of the present invention. Examples of the component (B3) include amine compounds other than the component (B1) and (B2). However, from the viewpoint that component (B3) may adversely affect the organic film, it is preferable to use component (B1) and component (B2) as component (B). Moreover, the total compounding amount of component (B1) and component (B2) is preferably 80% by mass or more, and more preferably 90% by mass or more, based on 100% by mass of component (B).

The amount of component (B) mixed is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 5% by mass or less, and 0.5% by mass or more and 2% by mass or less, based on 100% by mass of the water-soluble preflux. Particularly desirable. If the compounding amount of component (B) is more than the above lower limit, the heat resistance of the organic film formed can be further improved. In addition, it is preferable that the amount of component (B) is less than the above upper limit because it is difficult for the amount of component (B) to become excessive during continuous use of the water-soluble preflux.

[(C) component]

Examples of (C) organic acids used in this embodiment include formic acid, acetic acid, propionic acid, butanoic acid, enanthic acid, glycolic acid, tartaric acid, lactic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and methoxyacetic acid. I can hear it. Among these, from the viewpoint of making component (A) water-soluble, it is preferable to use formic acid, acetic acid, or enanthic acid, and it is especially preferable to use acetic acid or enanthic acid. In addition, these may be used individually by 1 type, or 2 or more types may be mixed and used.

The amount of component (C) mixed is preferably 1% by mass or more and 40% by mass or less, and more preferably 2% by mass or more and 30% by mass or less, based on 100% by mass of the water-soluble preflux. If the compounding amount of component (B) is within the above range, component (C) can be sufficiently dissolved in water.

[(D) component]

(D) water used in this embodiment is the remainder other than component (A), component (B), and component (C) in the water-soluble preflux, and other components described below.

[(E) component]

It is preferable that the water-soluble preflux according to the present embodiment further contains (E) a complex acid compound. The stability of the water-soluble preflux treatment liquid can be improved by this component (E).

Examples of complex acid compounds include sodium iron ethylenediaminetetraacetate and tetrasodium ethylenediaminetetraacetic acid hydrate.

When using component (E), the mixing amount is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, based on 100% by mass of the water-soluble preflux.

[(F) component]

It is preferable that the water-soluble preflux according to the present embodiment further contains (F) a complex film forming aid. However, when an additive for forming a complex film with copper is added, depending on the conditions, a film may be formed on the gold plating of the substrate, which may cause discoloration of the gold plating, so caution is required.

As complex film forming aids, copper formate, cuprous chloride, cupric chloride, copper oxalate, copper acetate, copper hydroxide, copper carbonate, copper phosphate, copper sulfate, manganese formate, manganese chloride, manganese oxalate, manganese sulfate, acetic acid. Metal compounds such as zinc, lead acetate, nickel acetate, barium acetate, zinc hydride, ferrous chloride, ferric chloride, ferrous oxide, copper iodide, cuprous bromide, and cupric bromide. can be mentioned. These complex film forming aids may be used individually, or two or more types may be mixed.

When using component (F), the mixing amount is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, based on 100% by mass of the water-soluble preflux.

[Other ingredients]

The water-soluble preflux according to this embodiment may contain organic solvents, buffer solutions, additives, etc., as long as they do not impair the effects of the present invention.

Examples of organic solvents include methanol, ethanol, and acetone.

Bases in the buffer include ammonia, diethylamine, triethylamine, diethanolamine, triethanolamine, monoethanolamine, dimethylethanolamine, diethylethanolamine, isopropylethanolamine, sodium hydroxide, and potassium hydroxide. there is.

When these are used, the mixing amount is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, based on 100% by mass of the water-soluble preflux.

[Surface treatment method]

Next, the surface treatment method according to this embodiment will be described.

The surface treatment method according to this embodiment is a method comprising the step of forming an organic film on an electrode terminal of an electronic board using the water-soluble preflux according to this embodiment.

Examples of electronic boards include printed wiring boards and semiconductor boards.

As a method of forming an organic film, for example, the surface of the electrode terminal of the printed wiring board to be treated is subjected to a pretreatment process of degreasing, chemical polishing (soft etching), pickling, and water washing, and then soaked in a water-soluble preflux at 10 to 60°C. A method of immersing the printed wiring board for 1 second to 100 minutes (preferably 5 seconds to 60 minutes at 20 to 50°C, more preferably 10 seconds to 10 minutes at 20 to 50°C) can be adopted. In this way, the imidazole compound adheres to the surface of the electrode terminal, but the amount of adhesion increases as the treatment temperature is raised and the treatment time is prolonged. At this time, it is more preferable to use ultrasonic waves. Additionally, the organic film may be formed by other application means, such as spraying, brushing, roller coating, etc.

In the above manner, an organic film (rust-prevention film, etc.) can be formed on the electronic substrate.

Example

Next, the present invention will be described in more detail by way of Examples and Comparative Examples, but the present invention is in no way limited by these examples. In addition, the materials used in the examples and comparative examples are shown below.

((A) component)

Imidazole Compound A: 2,4-diphenylimidazole

Imidazole Compound B: 2-[(4-methylphenyl)methyl]-1H-benzoimidazole

Imidazole Compound C: 2-[(4-chlorophenyl)methyl]-1H-benzoimidazole

Imidazole Compound D: 2-phenylbenzimidazole

((B1) component)

Amine compound A: hindered amine compound having two structures represented by general formula (B1-1) in one molecule, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, brand name “Tinuvin 770DF”, manufactured by BASF Corp.

((B2) component)

Amine compound B: N,N-dimethyldecylamine

((B3) component)

Amine compound C: N-phenylethylenediamine

Amine Compound D: Octylamine

((C) component)

Organic Acid A: Acetic Acid

Organic Acid B: Enanthic Acid

((D) component)

water: pure

((E) component)

Complex acid compound A: Sodium iron ethylenediaminetetraacetate, manufactured by Kishida Chemical Co., Ltd.

Complexan compound B: ethylenediaminetetraacetic acid tetrasodium hydrate

((F) component)

Complex film forming aid A: Ferric chloride (Iron(III) chloride)

Complex film forming aid B: Zinc acetate dihydrate

(other ingredients)

pH adjuster: ammonia water, manufactured by Kishida Chemical Co., Ltd.

[Example 1]

A water-soluble preflux was obtained by dissolving 0.3% by mass of imidazole compound A, 15% by mass of organic acid A, 0.1% by mass of organic acid B, 0.9% by mass of amine compound A, and 0.3% by mass of complex acid compound A in 83.4% by mass of water. . Additionally, the pH of the obtained water-soluble preflux was adjusted with 25 mass% aqueous ammonia as a buffer (pH adjuster) to obtain a water-soluble preflux treatment solution capable of forming a film.

[Examples 2 to 8]

A water-soluble preflux and a treatment solution were obtained in the same manner as in Example 1, except that each material was mixed according to the composition shown in Table 1.

[Comparative Examples 1 to 3]

A water-soluble preflux and a treatment solution were obtained in the same manner as in Example 1, except that each material was mixed according to the composition shown in Table 1.

<Evaluation of water-soluble preflux>

The performance (appearance, reflow heat resistance) of the water-soluble preflux was evaluated in the following manner. The obtained results are shown in Table 1.

(1) Appearance

Double-sided copper-clad laminate (size: 7.5 mm After washing with water and drying with warm air, a test board was obtained. About this test board, the appearance was observed and evaluated according to the following standards.

A: No unevenness or stripes are visible.

C: Irregularities or stripes are visible.

(2) Reflow heat resistance

After cleaning the surface of a copper plate (size: 50 mm It was dried with warm air to obtain a test board.

For this test board, reflow processing (preheat: 150 to 190°C for about 70 seconds, melt temperature: 220°C or higher for about 40 seconds, peak temperature: 250°C) was performed three times, and a solder composition (Tamura Corporation) was applied. A dewetting test was performed using the second solder paste “TLF-204-171A”). Then, reflow heat resistance was evaluated according to the following standards.

A: The wettability of the solder was good.

C: Clumps were seen in the solder.

As is clear from the results shown in Table 1, it was confirmed that the water-soluble preflux (Examples 1 to 8) of the present invention had both good appearance and reflow heat resistance. Therefore, it was confirmed that according to the present invention, a water-soluble preflux capable of forming an organic film with good heat resistance is obtained.

Claims (4)

Contains (A) an imidazole compound, (B) an amine compound, (C) an organic acid, and (D) water,
A water-soluble preflux wherein the component (B) contains at least one selected from the group consisting of (B1) a hindered amine compound and (B2) an amine compound having an alkyl group having 10 or more carbon atoms. According to claim 1,
(E) Water-soluble preflux further containing a complexan compound. The method of claim 1 or 2,
(F) Water-soluble preflux further containing a complex film forming aid. A surface treatment method comprising the step of forming an organic film on an electrode terminal of an electronic board using the water-soluble preflux according to claim 1 or 2.