KR101642378B1 - Novel imidazole compounds, surface treating agents, print circuit boards and a method of producing the same - Google Patents

Abstract

(Problem to be Solved) It is an object of the present invention to provide a process for producing a semiconductor device which is highly soluble in an aqueous solution of an organic acid, suppresses precipitation of an imidazole-based compound due to pH fluctuation or evaporation of the treatment solution, Thereby providing an imidazole compound suitable for a surface treatment agent as possible.

(Solution) A novel imidazole compound represented by the following general formula is provided. R ₁ represents hydrogen or a straight or branched alkyl group having 1 to 11 carbon atoms. R ₂ independently represents a straight-chain or branched-chain alkoxy group having 1 to 11 carbon atoms. R ₃ independently represents a linear or branched alkyl group having 1 to 11 carbon atoms, chlorine or bromine. m is an integer of 1 to 4, and n is an integer of 0 to 4.

New imidazole compounds, surface treatment agents, printed circuit boards

Description

TECHNICAL FIELD [0001] The present invention relates to a novel imidazole compound, a surface treatment agent, a printed circuit board, and a method for manufacturing the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a novel imidazole compound, a surface treatment agent, a printed circuit board and a method for producing the same.

The printed circuit board is obtained by forming a circuit wiring pattern on a copper-clad laminated board, for example, and mounting an electronic part thereon to form one circuit unit. Such a printed circuit board has a surface mount type in which a circuit pattern is formed on the surface of the printed circuit board and an electronic component is mounted on the circuit pattern. For example, in order to mount a chip component having electrodes on both ends as electronic components, the flux is applied to the printed circuit board, and then the chip component is soldered by a jet (flow) soldering method or a reflow soldering method. After the circuit pattern of the printed circuit board is formed, that is, the copper foil portion of the copper-clad laminate is etched so as to obtain a desired circuit wiring, a portion (so-called solder land portion) for soldering the chip component And then covered with a solder resist film. Then, the chip components may be directly soldered after performing the soft-etching treatment. However, it is often the case that the steps up to the step of coating with the solder resist film and the subsequent step of soldering the chip parts are performed independently. For example, a printed circuit board coated with a solder resist film is stored as a component, and then a soldering process of a chip component is performed again, or a solder process is performed by another vendor by circulating the printed circuit board. In such a case, since a long time may elapse before the soldering process is performed, the copper foil surface of the exposed solder land tends to be oxidized with air. Particularly, when moisture is high, air oxidation of the copper foil surface of the solder land tends to occur more easily. For this reason, an oxidation preventing film is formed to prevent oxidation of the surface, and a surface protecting agent is used for this purpose.

When a printed circuit board coated with a solder resist film is used soon after its production, if the electronic parts are mounted on both surfaces, for example, in a reflow soldering method, a solder paste is applied to a soldering land and then the solder powder is melted High temperature heating such as 260 占 폚 is performed. For this reason, when the soldering step is performed on one surface of the printed circuit board, the other surface is also exposed to a high temperature, and the copper foil surface of the solder land is easily oxidized.

When the oxidation protection treatment is performed on the solder land on the other side in order to prevent the thermal deterioration caused by the soldering process on one side of the printed circuit board, the so-called pre- flux is used. Of these, water-soluble free fluxes which do not use organic solvents and which do not cause pollution or fire are mainly used. Conventionally, the copper foil of the exposed solder land is subjected to anti-corrosive treatment. As described in Patent Documents 1 and 2, it is known to use a water-soluble surface protective agent for a printed wiring board containing a benzimidazole-based compound as a water-soluble preflux. Patent Documents 1 and 2 disclose that a printed board having a circuit pattern of copper foil is immersed in a surface protective agent for a water-soluble printed wiring board containing a benzimidazole-based compound so that the copper and copper alloy surfaces of the circuit pattern of the printed circuit board have heat resistance It is described that a film is formed. This film has a very good moisture resistance even after being exposed under high humidity, and is excellent in the protection of the printed circuit board and the solderability in the component mounting. Further, in the case of a free flux containing rosin and the like, the coating film is formed in addition to the copper foil, so that high reliability of the circuit may not be obtained unless an unnecessary coating film is cleaned after component mounting. Use of a water-soluble free flux as in Patent Documents 1 and 2 makes it unnecessary to clean such an unnecessary coating film, which is excellent in terms of productivity and performance.

Patent Document 1: JP-A-5-25407

Patent Document 2: JP-A-5-186888

BACKGROUND ART [0002] In recent years, a surface mounting method has been widely adopted as a method of bonding electronic components to a printed wiring board, so that the printed wiring board is exposed to high temperatures by temporarily fixing chip components, mounting the component devices on both sides, or combining chip components and discrete components However, when the surface treatment of a printed wiring board is performed using an imidazole compound having a long-chain alkyl group at the 2-position, when the printed wiring board is exposed to a high temperature, the surface treated by the surface treatment is discolored, It was not appropriate for law. Patent Documents 3 and 4 disclose that a heat-resistant film is formed on copper and copper alloy surfaces of a circuit pattern of a copper foil on a water-soluble surface protective agent for a printed wiring board containing an imidazole-based compound. The treatment liquid containing the midazol compound forms a chemical conversion coating film having excellent heat resistance on the surface of the copper metal to ensure good solderability after reflow heating in the surface mounting step, Is not precipitated and is stable. However, when these two-arylimidazole compounds are used for the surface treatment of a printed wiring board, a chemical conversion coating having excellent heat resistance can be formed on the surface of the metal, but this has been a problem to be solved in practical use.

Patent Document 3: Japanese Patent No. 3277025

Patent Document 4: Japanese Patent No. 3367743

That is, since these imidazole-based compounds have a low solubility in an aqueous solution of an organic acid, an imidazole-based compound tends to precipitate due to an increase in the pH of the adjusted treatment solution, evaporation of the treatment solution, The crystals were greatly grown and the redissolution was difficult. Particularly, when the storage temperature of the processing solution during the replenishment or in the tank in which the apparatus is not operated is low, the above problem is remarkable.

Disclosure of the Invention Problems to be Solved by the Invention A problem to be solved by the present invention is to provide a process for producing a semiconductor device which has high solubility in an aqueous solution of an organic acid and suppresses precipitation of an imidazole compound due to pH fluctuation or evaporation of the process solution, It is an object of the present invention to provide an imidazole compound suitable for use as a surface treatment agent.

A further object of the present invention is to provide a film having heat resistance by using a metal surface treatment agent using the imidazole compound and having excellent moisture resistance even after exposure to high humidity.

It is another object of the present invention to provide a solder land which is heated at high temperature by applying such a surface treatment agent to a printed circuit board so that molten solder can be well wetted and diffused.

The present invention relates to novel imidazole compounds represented by the following general formulas.

In the formulas, R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 11 carbon atoms. R ₂ independently represents a straight-chain or branched-chain alkoxy group having 1 to 11 carbon atoms. R ₃ independently represents a linear or branched alkyl group having 1 to 11 carbon atoms, chlorine or bromine. m is an integer of 1 to 4, and n is an integer of 0 to 4.

The present invention also relates to a metal surface treatment agent characterized by containing the imidazole compound.

Further, the present invention relates to a printed circuit board characterized by comprising a rustproof film formed by applying this surface treatment agent.

The present invention also relates to a method for surface treatment of a metal on a printed circuit board, characterized in that a rust preventive film is formed by applying the surface treatment agent on a metal film of a printed circuit board.

(Effects of the Invention)

According to the present invention, the dissolution of the imidazole-based compound due to the pH change of the treatment solution, the evaporation of the imidazole compound, or the like is suppressed and the stable use of the mixed solution by the printed wiring board and the soft etching treatment It is possible to provide an imidazole compound suitable for a surface treatment agent as far as possible.

Further, according to the present invention, it is possible to form a film having heat resistance and having excellent moisture resistance even after being exposed under a high humidity by using a metal surface treatment agent using the imidazole compound.

In addition, according to the present invention, by applying such a surface treatment agent to a printed circuit board, the molten solder can be well wetted and diffused even in a soldering land which is heated by high temperature.

[New imidazole compound]

In the formulas, R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 11 carbon atoms. Here, the number of carbon atoms of the alkyl group represented by R ₁ is more preferably from 1 to 7, and still more preferably from 1 to 4. Particularly preferably R < ₁ > is hydrogen.

R ₂ independently represents a straight-chain or branched-chain alkoxy group having 1 to 11 carbon atoms. Here, the carbon number of R ₂ is more preferably from 1 to 7, and still more preferably from 1 to 4. Particularly preferably, R ₂ is a methoxy group.

R ₃ independently represents a linear or branched alkyl group having 1 to 11 carbon atoms, chlorine or bromine. Here, the number of carbon atoms in R ₃ is more preferably from 1 to 7, and still more preferably from 1 to 4. Particularly preferably, R ₃ is a methyl group.

m is an integer of 1 to 4, with 1 to 2 being particularly preferred. N is an integer of 0 to 4, and 0 to 1 is particularly preferable.

[Synthesis of imidazole compound]

(Method 1)

In the imidazole compound of the present invention, when R ₁ is hydrogen, it can be synthesized, for example, as in (Step 1).

In the formulas, R ₂ independently represents a linear or branched alkoxy group having 1 to 11 carbon atoms. R ₃ independently represents a linear or branched alkyl group having 1 to 11 carbon atoms, chlorine or bromine. m is an integer of 1 to 4, and n is an integer of 0 to 4.

That is, in the first step, an acetophenone derivative (Formula 2) is synthesized with a brominating agent or a chlorinating agent, or? -Bromoacetophenones and? -Chloroacetophenones (Formula 3). As the brominating agent, a common brominating agent can be used, and bromine, pyridinium p-bromide, N-bromosuccinimide and the like can be exemplified, and preferably bromine. As the chlorinating agent, a common chlorinating agent can be used. Examples of the chlorinating agent include chlorine, thionyl chloride, sulfuryl chloride, phosgene, oxalyl chloride, phosphorus oxychloride, phosphorus pentachloride, phosphorus trichloride, ≪ / RTI > As these halogenating agents, commercially available ones can be used. These halogenation reactions may optionally be carried out using Lewis acid or Bronsted acid as catalyst. The halogenation can be carried out either without a solvent or with at least one solvent. Particularly suitable solvents for the reaction solvent are, for example, alcohols such as methanol, ethanol, 1,2-ethanediol, n-propanol, 2-propanol and n-butanol, n- , Aliphatic hydrocarbons such as toluene and xylene, aromatic hydrocarbons, aromatic hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane and chlorobenzene, aliphatic ethers such as diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, Alicyclic ether. Organic acids such as formic acid, acetic acid and propionic acid may also be used.

In the second step, the desired product can be obtained by reacting the? -Chloroacetophenones (Formula 3) with benzamidine in the presence of a base. Benzamidine can also be used in the form of a salt with a corresponding inorganic acid and / or an organic acid such as hydrochloride or sulfate. Particularly suitable solvents for the reaction solvent include acetic esters such as ethyl acetate and butyl acetate, alcohols such as methanol, ethanol, 1,2-ethanediol, n-propanol, 2-propanol, n- Aliphatic hydrocarbons such as hexane, n-pentane, cyclohexane, benzene, toluene and xylene; aromatic hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane and chlorobenzene; aromatic hydrocarbons such as diethyl ether, tetrahydrofuran, 2- Aliphatic ethers such as methyl tetrahydrofuran and dioxane, and alicyclic ethers. The reaction temperature and the concentration can be arbitrarily set at any stage.

(Method 2)

When the acetophenone as a raw material is not commercially available in the imidazole compound of the present invention, it can also be synthesized as in (Step 2), for example.

In the formulas, R ₁ represents hydrogen or a linear or branched alkyl group having 1 to 11 carbon atoms. R ₂ independently represents a straight-chain or branched-chain alkoxy group having 1 to 11 carbon atoms. R ₃ independently represents a linear or branched alkyl group having 1 to 11 carbon atoms, chlorine or bromine. m is an integer of 1 to 4, and n is an integer of 0 to 4.

That is, when R ₁ is hydrogen, haloacetic acid chloride (X-CH ₂ -COCl 3 X is chlorine or bromine) or haloacetic acid bromide (X-CH ₂ -COBr 4) is added to the substituted benzenes (Formula 4) X is chlorine or bromine) to synthesize? -Halo-acetophenones (Formula 3). This reaction is suitable for the Friedel-Crafts acylation reaction, and the reaction can be carried out in the presence of a general Lewis acid, such as aluminum chloride, applied to this reaction. As the haloacetic acid chloride, chloroacetic acid chloride, bromoacetic acid chloride, and haloacetic acid bromide, chloroacetic acid bromide, bromoacetic acid bromide and the like, preferably chloroacetic acid chloride.

When R ₁ is a straight or branched alkyl group having 1 to 11 carbon atoms, the corresponding acid chloride or acid bromide is subjected to a Friedel-Crafts acylation reaction in the same manner as described above. Then, a brominating agent or chlorination A zero acetophenone derivative (Formula 3) can be prepared. The second step can also be synthesized by the same method after benzamidine. The reaction temperature and the concentration can be arbitrarily set at any stage.

[Metal surface treatment agent]

The surface treatment agent of the present invention contains a novel imidazole compound.

In a preferred embodiment, the surface treatment agent of an aqueous solution containing an imidazole compound as an essential component in an amount of 0.01 to 10 mass%, more preferably 0.05 mass% or more, or 5 mass% or less is used. When the content of the imidazole compound is 0.01% or more, a coating film such as a rust-preventive film is easily formed. When the content is more than 10% by mass, the amount of insoluble solute is liable to increase, which is not economical.

Since the imidazole compound is poorly soluble in neutral water, the imidazole compound is hydrated with an organic acid. At this time, a water-soluble organic solvent may be used in combination.

Examples of the organic acid used in this case include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, Linolenic acid, dihomo-y-linolenic acid, arachidonic acid, oleic acid, erucic acid, erucic acid, erucic acid, erucic acid, But are not limited to, acids, glycolic acid, lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, malic acid, tartaric acid, citric acid, isocitric acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, methoxyacetic acid, P-toluenesulfonic acid, picric acid, meta-toluic acid, succinic acid, salicylic acid, maleic acid, fumaric acid, adipic acid, glutaric acid and levulic acid, Particularly, formic acid and acetic acid are preferable. These acids are preferably contained in an amount of 1 to 40% by mass. Examples of the water-soluble organic solvent that can be used at this time include alcohols such as methanol, ethanol, 1,2-ethanediol, n-propanol, 2-propanol and n-butanol, acetone, N, N-dimethylformamide, .

Examples of the metal to be treated with the surface treatment agent include alloys of copper, copper, phosphorus, and nickel, nickel, tin, zinc, silver-palladium alloy, and alloys containing these metals as a main component.

The surface treatment agent (preferably water-soluble pre-flux) of the present invention may contain, as a complexing agent for forming a complex with copper, for example, formic acid copper, cuprous chloride, cupric chloride, oxalic acid copper, Copper, copper, copper, copper, copper, copper, copper, copper, copper, copper manganese, manganese formate, manganese chloride, manganese oxalate, manganese oxalate, manganese sulfate, zinc acetate, lead acetate, zinc hydride, ferrous chloride, A metal compound such as iron, iron iodide, copper bromide, copper bromide and copper bromide, and a metal compound such as ethylenediamine, ethylenediaminetetraacetic acid, iminodiacetic acid, nitrilotriacetic acid, glycolic acid, crown ether, bipyridine, porphyrin, Chelates such as phosphorus, and other cyclic coordination compounds may be further added. These are used singly or in combination of two or more, and the addition amount is 0.01 to 10% by mass, preferably 0.05 to 5% by mass, based on the treatment liquid.

It is also preferable to use a buffer solution containing a metal ion using the above metal compound in combination. As typical bases for this, ammonia, diethylamine, triethylamine, diethanolamine, triethanolamine, monoethanolamine, dimethylethanolamine, Diethylethanolamine, isopropylethanolamine, hydrazine, sodium hydroxide, potassium hydroxide and the like.

The surface treatment agent of the present invention may further contain a halogen compound such as potassium iodide, potassium bromide, zinc iodide, zinc bromide, ammonium iodide, ammonium bromide, bromopropionic acid and iodopropionic acid, , A methylpyridinium bromide salt, a heterocyclic compound, or a halogen salt of an amine compound may be added. These are used alone or in combination of two or more, and the addition amount is 0.01 to 10% by mass, preferably 0.05 to 5% by mass, based on the treatment liquid.

From these points, the water-soluble free flux containing the imidazole compound and the organic acid represented by the general formula (1) may contain at least one of the metal compound, the coordination compound and the halogen compound.

To form a rust preventive film by applying the water-soluble pre-flux of the present invention to the rust-preventive treatment, the surface of the copper layer of the printed circuit board to be treated is subjected to a pretreatment step of polishing, degreasing, pickling and washing with water, The printed circuit board is immersed for a few seconds to several tens of minutes, preferably 20 to 50 ° C, for 5 seconds to 1 hour, preferably 10 seconds to 10 minutes. Thus, the imidazole compound according to the present invention adheres to the copper layer, but the amount of the imidazole compound increases as the treatment temperature is increased and the treatment time is increased. It is better to use ultrasonic waves. Further, other application means such as a spraying method, a brush application method, a roller application method, and the like can also be used. The rust preventive film thus obtained can be well wetted with molten solder even in a solder land which is heated at high temperature by double-sided mounting or the like and is deteriorated.

Further, the heat-resistant property of the printed circuit board on which the water-soluble free flux is applied and the rust-preventive film formed may be uniformly coated with a thermoplastic resin having excellent heat resistance, such as a rosin derivative or a terpene phenol resin, dissolved in a solvent by a roll coater or the like .

In order to manufacture the printed circuit board of the present invention, for example, the following steps are performed.

(1) a step of forming a circuit pattern comprising predetermined circuit wiring having a soldering land for soldering chip parts on a substrate made of a copper-clad laminate by etching, and coating the area other than the soldering land with the solder resist

(2) a pretreatment step of polishing the copper surface of the circuit pattern, degreasing, pickling (soft etching), and washing with water

(3) a step of applying and drying a water-soluble free flux containing at least one compound selected from the group consisting of the compounds represented by the above general formula (1)

(4) Solder paste (containing solder powder and flux) is directly applied to the solder land after the post flux is applied or not applied to the obtained printed circuit board, and the electrode of the chip component is reflow soldered.

(Example)

Embodiments of the present invention will be described with reference to the following examples. In addition, "% " is " mass% " unless otherwise specified.

[One. Synthesis of new imidazole]

[Production Example 1]

(Preparation of 2-phenyl-4- (2-methoxy) phenylimidazole)

To a solution of o-methoxyacetophenone (300 g) dissolved in toluene (500 ml), bromine (320 g) was added dropwise over 3 hours while maintaining the temperature at 5 to 10 ° C with stirring. Then, water (500 ml) was added at 20 캜 or lower, and potassium carbonate (300 g) was added for 1 hour to neutralize. Then, ethyl acetate (500 ml) and water (500 ml) were added to extract the organic layer. The organic layer was washed twice with saturated brine (500 ml), and the resultant? -Bromo (2-methoxy) acetophenone was used in the next reaction without isolation. The obtained organic layer was mixed with benzamidine hydrochloride (320 g), potassium carbonate (800 g) and water (600 ml), and the mixture was stirred at 60 캜 for 6 hours. The reaction solution was neutralized using potassium hydroxide while cooling, and ethyl acetate (1 L) was added to extract the organic layer. The organic layer was washed three times with saturated saline (1 L) and concentrated to 150 mL on an Evaporator. Hexane (1 L) was added, and the mixture was stirred at room temperature. The resulting crystals were filtered to obtain 150 g of 2-phenyl-4- (2-methoxy) phenylimidazole.

(D), 7.29 (t), 7.37 (t), 7.45 (m), 7.80 (s), 8.02 (d) d)

[Production Example 2]

(Preparation of 2-phenyl-4- (3-methoxy) phenylimidazole)

methoxyacetophenone (250 g) and methylene chloride (1 kg), and sulfuric chloride (250 g) was added dropwise while stirring at 0-5 ° C. The resulting gas was continuously added dropwise for 2 hours while trapping, and then stirred at room temperature for 5 hours. The organic layer was washed twice with 5% aqueous potassium carbonate solution (1 L) and then twice with water. The organic layer was concentrated to half and hexane (2 L) was added and allowed to stand at room temperature. After 10 hours, the resulting crystals were filtered under reduced pressure to obtain 140 g of? -Chloro (3-methoxy) acetophenone. Subsequently, 140 g of the obtained? -Chloro (3-methoxy) acetophenone, 120 g of benzamidine hydrochloride, 240 g of sodium hydrogencarbonate, 1 L of tetrahydrofuran and 500 mL of water were mixed to obtain 60 C < / RTI > for 6 hours. The reaction solution was cooled and neutralized with ammonia, and ethyl acetate (1 L) was added to extract the organic layer. The organic layer was washed three times with saturated saline (1 L) and concentrated to 100 mL with Evaporator. Hexane (1 L) was added thereto, and the mixture was stirred at room temperature. The resultant crystals were filtered to obtain 127 g of 2-phenyl-4- (3-methoxy) phenylimidazole.

(D), 7.29 (t), 7.36 (t), 7.48 (m), 7.79 (s), 8.02 (d) d)

[Production Example 3]

(Preparation of 2-phenyl-4- (3-ethoxy) phenylimidazole)

phenyl-4- (3-ethoxy) phenylimidazole was obtained in the same manner as in [Manufacturing Example 1] except that m-ethoxyacetophenone (100 g) was used instead of o-methoxyacetophenone.

7.28 (t), 7.37 (t), 7.48 (m), 7.79 (s), 8.02 (d) d)

[Production Example 4]

(Preparation of 2-phenyl-4- (3,4-dimethoxy) phenylimidazole)

4-dimethoxyacetophenone (100 g) was used in the same manner as in [Manufacturing Example 2] to obtain 45 g of 2-phenyl-4- (3-ethoxy) phenylimidazole.

(D), 7.02 (d), 7.21 (d), 7.30 (s), 7.39 (t), 7.57 (s), 1H NMR (400 MHz, CDCl3) , 7.82 (d), 10.84 (m)

[Production Example 5]

(Preparation of 2-phenyl-4- (3,4-dimethoxy) phenyl-5-methylimidazole)

100 g of 1,2-dimethoxybenzene and 150 g of anhydrous aluminum chloride were added to 600 g of methylene chloride, and 70 g of propionic acid chloride was added dropwise over 3 hours while maintaining the temperature below 5 ° C. Thereafter, the resulting gas was stirred at room temperature for 3 hours while trapping it, followed by addition of 5% hydrochloric acid (300 ml), and the mixture was stirred at room temperature for 1 hour. The organic layer was washed twice with a 5% aqueous solution of potassium carbonate (500 ml) and then twice with water. The organic layer was dehydrated with anhydrous sodium sulfate and filtered. Thereafter, the solution was adjusted to 0 占 폚, and sulfuric chloride (100 g) was added dropwise over 3 hours. Thereafter, the resulting gas was stirred at room temperature for 5 hours while trapping it, and washed with 2% aqueous potassium hydroxide solution (120 ml) twice while cooling. Subsequently, the organic layer was concentrated to half, and then benzamidine hydrochloride (95 g), sodium hydrogencarbonate (270 g), tetrahydrofuran (600 ml) and water (300 ml) were mixed and stirred at 60 ° C for 6 hours . The reaction solution was neutralized using ammonia while cooling, and ethyl acetate (500 ml) was added to extract the organic layer. The organic layer was washed three times with saturated brine (500 mL) and concentrated to 100 mL with Evaporator. Hexane (300 ml) was added, and the mixture was stirred at room temperature. The resulting crystals were filtered to obtain 50 g of 2-phenyl-4- (3,4-dimethoxy) phenyl-5-methylimidazole.

7.28 (d), 7.25 (m), 7.39 (t), 7.57 (s), 7.80 (d) , 10.82 (m)

[Production Example 6]

(Preparation of 2-phenyl-4- (2-methoxy-5-methyl) phenylimidazole)

A solution of methyl anisole (30 g) and chloroacetyl chloride (50 g) was added dropwise to trifluoromethanesulfonic acid (100 g) at 0-5 ° C over 3 hours. Thereafter, the reaction solution was added to the ice water (1 L) while stirring slowly. The mixture was stirred for 3 hours while cooling, and the resulting white crystals were filtered to obtain? -Chloro (2-methoxy-5-methyl) acetophenone (35 g). Subsequently, benzamidine hydrochloride (30 g), sodium hydrogencarbonate (80 g), toluene (100 ml) and water (100 ml) were added, followed by stirring at 50 ° C for 5 hours. The reaction solution was neutralized using ammonia while cooling, and ethyl acetate (200 ml) was added to extract the organic layer. The organic layer was washed three times with saturated saline (200 ml) and concentrated to 50 ml in an Evaporator. Hexane (100 ml) was added, and the mixture was stirred at room temperature, and the resulting crystals were filtered to obtain 22 g of 2-phenyl-4- (2-methoxy-5-methyl) phenylimidazole.

NMR (400 MHz, CDCl3): 2.28 (s), 3.86 (s), 6.86 (d), 7.36 (t), 7.44 (t), 7.64 d)

[Production Example 7]

(Preparation of 2-phenyl-4- (2-chloro-5-methoxy) phenylimidazole)

34 g of aluminum chloride was mixed with 150 g of methylene chloride at 5 DEG C and a mixed solution of 4-chloroanisole (30 g) and chloroacetyl chloride (26 g) was added dropwise to the solution at 5 DEG C or less for 3 hours . Thereafter, the produced gas was stirred at room temperature for 3 hours while trapping. Thereafter, 5% hydrochloric acid (100 ml) was added, and the mixture was stirred at room temperature for 1 hour. The organic layer was extracted, washed twice with 2% aqueous potassium hydroxide solution (120 ml), and then washed twice with water. The organic layer was concentrated to half, and then benzamidine hydrochloride (120 g), sodium hydrogencarbonate (240 g), tetrahydrofuran (500 ml) and water (300 ml) were mixed and stirred at 60 캜 for 6 hours. The reaction solution was cooled and neutralized with ammonia, and then ethyl acetate (500 ml) was added to extract the organic layer. The organic layer was washed three times with saturated saline (500 ml) and concentrated to 100 ml in an Evaporator. Hexane (300 ml) was added, and the mixture was stirred at room temperature. The resulting crystals were filtered to obtain 18 g of 2-phenyl-4- (2-chloro-5-methoxy) phenylimidazole.

(D), 7.29 (t), 7.34 (t), 7.59 (d), 7.74 (s), 7.87 (d), 1H NMR (400 MHz, CDCl3) , CDCl3

[Production Example 8]

(Preparation of 2-phenyl-4- (2,5-dimethoxy-3-methyl) phenylimidazole)

(2-phenyl-4- (2,5-dimethoxy-3-methyl) phenyl) imidazole was obtained in the same manner as in [Manufacturing Example 7] except that 2,5-dimethoxy toluene I got a sol.

(T), 7.395 (t), 7.877 (d), 7.38 (t), 7.38 (t) , 10.172 (m), (CDCl3)

[Production Example 9]

(Preparation of 2-phenyl-4- (2,3,5-trimethoxy-6-methyl) phenylimidazole)

(2-phenyl-4- (2,5-dimethoxy-3-methyl) pyridin-2-yl) -amide was prepared in the same manner as in [Manufacturing Example 7], except that 2,4,5-trimethoxytoluene Phenylimidazole was obtained.

NMR (400 MHz, CDCl3): 3.733 (s), 3.895 (s), 3.911 (s), 6.641 (s), 7.364 (t), 7.450 (t), 7.880 (d) , 10.242 (m), (CDCl3)

[2. Blending and Evaluation of Surface Treatment Agent]

(2) a solution stability test of a surface treatment agent; (3) a solution stability test of the surface treatment agent (water-soluble preflux); and (3) (4) the heat resistance of the coating film by the surface treatment agent, and the test for humidifying deterioration will be described.

(1) The novel imidazole and comparative compound of the present invention are mixed with the surface treatment agent (water-soluble free flux)

[Example 1]

A process capable of forming a coating film by dissolving 0.3% of 2-phenyl-4- (2-methoxy) phenylimidazole, 10% of acetic acid and 0.05% of zinc bromide in Production Example 1 and adjusting the pH with ammonia water and pure water I made it.

[Example 2]

0.3% of 2-phenyl-4- (3-methoxy) phenylimidazole, 20% of acetic acid, 0.05% of enantiic acid and 0.05% of zinc iodide were dissolved in ammonia water and pure water, To form a treatment liquid capable of forming a film.

[Example 3]

, 0.2% of 2-phenyl-4- (3-ethoxy) phenylimidazole, 5.00% of formic acid, 10.00% of acetic acid, 0.03% of ammonium iodide and 0.05% of ethylenediaminetetraacetic acid in [Preparation Example 3] The pH was adjusted with pure water to prepare a treatment liquid capable of forming a film.

[Example 4]

0.25% of 2-phenyl-4- (3,4-dimethoxy) phenylimidazole, 10.00% of acetic acid, 1.00% of glycolic acid, 0.05% of ammonium bromide and 0.05% of iminodiacetic acid in [Preparation Example 4] Ammonia water and pure water to adjust the pH, thereby obtaining a treatment liquid capable of forming a film.

[Example 5]

0.25% of 2-phenyl-4- (4-methoxy) phenyl-5-methylimidazole, 10.00% of methoxyacetic acid and 0.05% of acetic acid copper in Production Example 5 were dissolved, and pH was adjusted with ammonia water and pure water Thereby forming a treatment liquid capable of forming a film.

[Example 6]

0.30% of 2-phenyl-4- (2-methoxy-5-methyl) phenylimidazole, 30.00% of acetic acid, 0.10% of caproic acid and 0.05% of potassium bromide were dissolved in ammonia water and pure water The pH was adjusted to obtain a treatment liquid capable of forming a film.

[Example 7]

0.20% of 2-phenyl-4- (2-chloro-5-methoxy) phenylimidazole, 15% of acetic acid, 0.10% of citric acid, 0.30% of zinc acetate and 0.10% of triethanolamine in [Preparation Example 7] Ammonia water and pure water to adjust the pH, thereby obtaining a treatment liquid capable of forming a film.

[Example 8]

0.20% of 2-phenyl-4- (2,5-dimethoxy-3-methyl) phenylimidazole of Preparation Example 8, 20.00% of acetic acid, 0.10% of malic acid, 0.05% of tetramethylammonium iodide, 0.10% And the pH was adjusted with ammonia water and pure water to obtain a treatment liquid capable of forming a film.

[Example 9]

0.20% of 2-phenyl-4- (2,3,5-trimethoxy-6-methyl) phenylimidazole, 10.00% of formic acid, 20.00% of acetic acid and 0.05% of potassium iodide were dissolved in [ Ammonia water and pure water to adjust the pH, thereby obtaining a treatment liquid capable of forming a film.

[Comparative Example 1]

0.80% of 2-pentylimidazole, 2.00% of acetic acid and 0.05% of zinc bromide were dissolved, and the pH was adjusted with ammonia water and pure water to obtain a treatment liquid capable of forming a film.

[Comparative Example 2]

1.00% of 2-phenylimidazole, 1.00% of formic acid, 1.00% of acetic acid and 0.05% of zinc bromide was dissolved, and the pH was adjusted with ammonia water and pure water to obtain a treatment liquid capable of forming a film.

[Comparative Example 3]

0.30% of 2,4-diphenylimidazole, 10.00% of acetic acid and 0.05% of zinc bromide were dissolved, and the pH was adjusted with ammonia water and purified water to obtain a treatment liquid capable of forming a film.

(2) Solution stability test of surface treating agent

The stability of the surface treatment agent (water-soluble free flux) of the present invention was evaluated by the following test.

(2-1: low temperature stability)

The treating agent was placed in a 300 cc polypropylene flask and stored at 5 ° C for 7 days. The crystals after 7 days or the precipitation state of the oil phase were observed. The results are shown in Table 1.

(2-2: Stability of stirring)

A 300 cc polypropylene flask was charged with a treating agent and a stirrer, and stirred with a magnetic stirrer to observe the state of precipitation of crystals or oil phase after 7 days. The results are shown in Table 1.

(2-3: stability of sulfuric acid and chlorine ion inclusion)

In a 300 cc polypropylene flask, 0.1% (1000 ppm) of sulfuric acid or hydrochloric acid was added to the flask and stirred with a magnetic stirrer to observe the crystal state and precipitation state of the oil phase after 7 days. The results are shown in Table 1.

(3) Process of forming a film on the surface of a copper clad laminate by a surface treatment agent

(3-1) Cleaning and preparation of evaluation substrate

An evaluation board having a copper foil surface cleaned in advance by a soft etching agent (trade name: SE-30M, Tamura Kaken Kabushiki Kaisha) was taken out and washed with water and removed with a liquid.

Subsequently, the evaluation substrate was immersed in the surface treating agent containing the novel imidazole of the present invention and the comparative compound prepared above at 40 캜 for 60 seconds, drawn out, washed with water and dried. Using the test pieces thus treated, the heat resistance and humidification deterioration test of the coating film by the surface treatment agent were carried out as follows.

(4) Heat resistance and humidification deterioration test of the film by the surface treatment agent

(4-1: heat deterioration treatment)

For the heat resistance test of the water-soluble pre-flux coating, an air reflow furnace having a temperature profile shown in Fig. 1 was used and the heat deterioration treatment of the printed circuit board was carried out by performing reflow treatment a plurality of times.

(4-2: humidification deterioration treatment)

The wettability deterioration test of the water-soluble pre-flux coating was carried out by placing it in a constant temperature and humidity layer of 40 ° C. and 90% RH for 96 hours.

(4-3: solder diffusivity test (1))

As the test substrate, a JIS2 type interdigital substrate was used and a rustproof film was formed by the above-described method.

The test substrate on which the film was formed was subjected to heat treatment at 0 to 3 times under the above reflow condition and solder paste (trade name: RMA-010NFP, manufactured by Tamura Kaken Co., Ltd.) was applied to a metal mask having an opening width of 0.635 mm and a thickness of 200 탆 Character printing was performed, and the diffusion length of the solder was measured by performing reflow heat treatment. The longer the diffusion length of the solder at this time, the higher the wettability of the solder. The evaluation results of each water-soluble free flux are shown in Table 2.

(4-4: solder diffusivity test (2))

As the test substrate, a JIS2 type interdigital substrate was used and a rustproof film was formed by the above-described method.

The test substrate on which the film was formed was subjected to a humidifying and deteriorating treatment, and then subjected to heat treatment at 0 to 3 times under the reflow condition. Thereafter, a solder paste (trade name: RMA-010NFP manufactured by Tamura Kaken K.K.) And the diffusion length of the solder was measured by performing the reflow heat treatment. The longer the diffusion length of the solder at this time, the higher the wettability of the solder. The evaluation results of the examples are shown in Table 2.

(4-5: Through hole solder lift test (1))

A substrate having 360 holes of through holes with an inner diameter of 0.6 to 1.0 mm was used as a test substrate and a rustproof film was formed by the above method. The test substrate on which the film was formed was subjected to heat treatment at 0 to 3 times under the above reflow conditions and then a post flux (trade name: CF-110VH-2A, manufactured by Tamura Kaken Co., Ltd.) was applied and soldered using a flow soldering apparatus And the ratio of the number of through holes whose solder rises to the top of the through hole was measured. Table 3 shows the evaluation results of each water-soluble free flux.

(4-6: Through hole solder lift test (2))

A substrate having 360 holes of through holes with an inner diameter of 0.6 to 1.0 mm was used as a test substrate and a rustproof film was formed by the above method. The test substrate on which the film was formed was subjected to a humidifying and deteriorating treatment and then subjected to heat treatment at 0 to 3 times under the above reflow conditions. Thereafter, a post flux (trade name: CF-110VH-2A made by Tamura Kaken Kabushiki Kaisha) Soldering was performed using the apparatus, and the ratio of the number of through holes whose solder rises to the top of the through hole was measured. Table 3 shows the evaluation results of each water-soluble free flux.

As can be seen from Tables 1 to 3, the surface treatment agent for a metal containing a novel imidazole compound provided by the present invention is very stable, has a high solubility in an aqueous solution, Precipitation of the imidazole-based compound is suppressed, and the surface treatment agent can be used for stable use even in the incorporation of a job-on by a printed wiring board or a soft-etching treatment.

In addition, by using a metal surface treatment agent using the same at the same time, it is possible to form a film having heat resistance and excellent moisture resistance even after being exposed under high humidity, and a soldering land which is heated by high temperature by applying such surface treatment agent to a printed circuit board The molten solder is well wetted and diffused.

Fig. 1 shows the temperature profile of the air reflow in the heating deterioration test.

Claims (7)

A surface treatment agent for a metal characterized by containing an imidazole compound represented by the following general formula.

(Wherein, R ₁ represents a hydrogen or a methyl group. R ₂ represents an independently methoxy group or ethoxy group from each other. R ₃ represents a methyl group or chlorine. M is an integer of 1 ~ 3 n is from 0 to 1 Integer) The surface treatment agent for a metal according to claim 1, which contains an organic acid. The metal surface treatment agent according to claim 1 or 2, wherein the content of the imidazole compound is 0.01 to 10% by mass. The metal surface treatment agent according to claim 2, wherein the content of the organic acid is 1 to 40% by mass. A printed circuit board characterized by comprising a rustproof film formed by applying the surface treatment agent for a metal according to any one of claims 1, 2, and 4. A method for surface treatment of a printed circuit board metal characterized by forming a rustproof film by applying the surface treatment agent of the metal of any one of claims 1, 2 or 4 on a metal film of a printed circuit board. delete

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