JPH06177535A - Metal surface treatment agent - Google Patents

Abstract

PURPOSE:To realize a metal surface treating agent which enables a metal surface to be enhanced in rust-resisting properties and adhesive properties to a resin board by a method wherein a mixture of specific imidazolyl silane compound and specific bistrialkoxysilyl compound is used as a metal surface treating agent. CONSTITUTION:Metal surface treating agent is a mixture of new imidazole silane compound represented by formulas I, II, and/or III and bistrialkoxysilyl compound B represented by a formula, (R<4>O)3SiR<6>Si(OR<5>)3, as effective constituents, wherein R<5>O denotes a lower alkoxyl group where the number of carbon atoms is 1 to 4, and R<6> indicates an alkylene group whose number of carbon atoms is 1 to 8. In the formulas I, II, and III, R<1> is an alkyl group where the number of carbon or hydrogen atoms is 1 to 20, R<2> denotes an alkyl group whose number of hydrogen atoms, vinyl groups, or carbon atoms is 1 to 5, R<3> and R<4> are an alkyl group whose number of carbons is 1 to 3, and n denotes an integer of 1 to 3. By this setup, when a printed board is treated by the above treating agent and then mounted, it is hardly separated off under conditions that temperature and humidty are both high, so that it can be improved in reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal surface treating agent for preventing rust or improving adhesiveness of a metal surface.

[0002]

A copper clad laminate for a printed circuit is formed by laminating a copper foil on a paper-phenol resin-impregnated base material or glass-epoxy resin-impregnated base material by heating and pressurizing it. A board for electronic equipment is made by forming a circuit network and mounting an element such as a semiconductor device on the circuit network.
In these processes, adhesion with a base material, heating, immersion in an acid or alkaline solution, application of resist ink, soldering, etc. are performed, so that various performances are required for the copper foil. For example, the side that is usually called the M surface (roughened surface, the same applies below) is mainly required to have adhesiveness with the base material, chemical resistance, etc. Usually S side (glossy surface,
The same shall apply hereinafter) is mainly required to have heat resistance and moisture resistance. It is also required that the copper foils on both sides of the copper foil do not undergo oxidative discoloration during storage. In order to satisfy these requirements, a brass layer forming treatment (Japanese Patent Publication No. S51-35711, No. 54-6701) on the M side of the copper foil, chromate treatment, zinc or oxidation on both sides of M and S. A coating treatment of a zinc-chromium group mixture consisting of zinc and chromium oxide (Japanese Patent Publication No. 58-7077) has been carried out. By the way, recently, regarding the heat resistance of the S side of copper foil, due to the advent of high heat resistant resins, etc.
Therefore, it is required that oxidative discoloration does not occur even under high temperature conditions such as 220 ° C. or 240 ° C. × 30 minutes. In addition, the demand for finer printed wiring boards has increased more and more in recent years, and in order to respond to the improvement in etching accuracy accompanying this, lower surface roughness (low profile) is also required for the M surface. There is. On the other hand, the surface roughness of the M-side, on the other hand, brings about an anchoring effect in adhering to the substrate. Therefore, there is a trade-off relationship between the requirement of the low profile for the M-side and the improvement of the adhesive strength, and the low profile is required. It is necessary to compensate for the reduction in the anchor effect due to the above by improving the adhesive force by another means.

Further, a method of applying a silane coupling agent to the M surface has also been proposed as a means for increasing the adhesive force or a means for increasing the adhesive force due to the above-mentioned low profile (Japanese Patent Publication No. 2-19994, Kai 63-1
83,178, and JP-A-2-26097).

As this type of silane coupling agent,
Vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- 2- (aminoethyl)-
3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-
Mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, etc. are known ["Latest Technology of Polymer Additives", pp. 120-134, CMC,
Published January 6, 1988].

[0005]

However, since the printed circuit has been densified recently as described above, the characteristics required for the copper foil for the printed circuit used have become more and more severe. The present invention can meet these requirements, that is, a novel metal surface treatment agent using a specific silane compound that has a high rust preventive effect on the metal surface and can significantly improve the adhesion between the metal and the resin substrate. In particular, the object is to provide a surface treatment agent for copper foil.

[0006]

Means for Solving the Problems As a result of intensive research, the present inventor has found that a mixture of a specific imidazole silane compound and a specific bistrialkoxysilyl compound has an excellent rust preventive action on a metal surface, It has been found that the adhesion between the metal and the resin substrate is significantly improved.

The present invention has been made based on such findings, and the gist thereof is a novel imidazole silane compound (A) represented by the following general formulas (1), (2) and / or (3) and the following: Metal surface treating agent containing a bistrialkoxysilyl compound (B) represented by the general formula (4) as an active ingredient

[0008]

[Chemical 2]

(However, in the general formula (1), (2) or (3), R ¹ is hydrogen or an alkyl group having 1 to 20 carbon atoms, R ² is hydrogen, a vinyl group or 1 to 5 carbon atoms. Alkyl group, R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms,
n is 1 to 3) (R ⁵ O) ₃ SiR ⁶ Si (OR ⁵ ) ₃ (4) (wherein R ⁵ O is a lower alkoxy group having 1 to 4 carbon atoms,
R ⁶ represents an alkylene group having 1 to 8 carbon atoms).

The imidazole silane compound (1), (2) and / or (3), which is the component (A) of the metal treating agent of the present invention, comprises the imidazole compound represented by the general formula (5) and the general formula (6). ) And the 3-glycidoxy propyl silane compound represented by these are reacted at 80-200 degreeC, and it can manufacture. The reaction is expressed by the following equation.

[0011]

[Chemical 3]

(In the above formula, R ¹ is hydrogen or has 1 to 1 carbon atoms.
20 alkyl groups, R ² is hydrogen, vinyl group or 1 carbon atom
~ 5 alkyl group, R ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms, and n represents 1 to 3) The imidazole compound represented by the general formula (5) is preferably imidazole, 2- Alkylimidazole, 2,4-dialkylimidazole, 4-vinylimidazole and the like. Among these, particularly preferable are imidazole; 2-alkylimidazole is 2-methylimidazole, 2
-Ethyl imidazole, 2-undecyl imidazole,
2-Heptadecylimidazole; As the 2,4-dialkylimidazole, 2-ethyl-4-methylimidazole and the like can be mentioned. The 3-glycidoxypropylsilane compound represented by the general formula (6) is 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyldialkoxyalkylsilane, 3-glycidoxypropylalkoxydialkyl. Silanes, and particularly preferable ones among these, include 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of the sidoxypropyl dialkoxyalkylsilane include 3-glycidoxypropyldimethoxymethylsilane, and examples of the 3-glycidoxypropylalkoxydialkylsilane include 3-glycidoxypropylethoxydimethylsilane.

The reaction between the imidazole compound and the 3-glycidoxypropylsilane compound is carried out by adding 0.1- to 10-fold molar amount of the 3-glycidoxypropylsilane compound to the imidazole compound heated to a temperature of 80 to 200 ° C. It is advisable to carry out the reaction while dropping, and a reaction time of about 5 minutes to 2 hours is sufficient. This reaction does not require a solvent, but
An organic solvent such as chloroform, dioxane, methanol or ethanol may be used as a reaction solvent. Since this reaction does not like water, it is preferable to carry out the reaction in an atmosphere of a gas containing no water such as dry nitrogen or argon so as not to mix water.

In this reaction, in the above general formula (1),
The imidazolesilane compounds shown in (2) and (3) are obtained in the form of a mixture, and these compounds are purified and isolated by a known means such as a method utilizing the difference in solubility or column chromatography. sell. When used as the metal surface treating agent of the present invention, these imidazole silane compounds do not necessarily have to be isolated, and it is preferable to use the mixture as it is because it is simple. The composition of each component in the product is generally expressed by the general formula (1): the same (2): the same (3) = (40 to 80): (10 to 30): (5 to 4)
0) (area ratio when analyzed by liquid chromatography).

The preferred examples of the bistrialkoxysilyl compound which is the component (B) of the metal treating agent of the present invention include the following.

(CH ₃ O) ₃ Si (CH ₂ ) ₂ Si (OCH
₃ ) ₃ , (CH ₃ O) ₃ Si (CH ₂ ) ₃ Si (OCH ₃ ) ₃ ,
_{(CH 3 O) 3 Si (} CH 2) 4 Si (OCH 3) 3, (CH
_{All of 3} O) ₃ Si (CH ₂ ) ₆ Si (OCH ₃ ) ₃ and the bistrialkoxysilyl compound used in the present invention can be synthesized by known methods. For example, a bistrialkoxysilylalkylene compound can be synthesized by reacting a chloroalkyltrialkoxysilane or a tetraalkoxysilane in the presence of lithium (JP-A-64-6036). Alternatively, a commercially available product [eg, manufactured by Nitto Corp. or Toshiba Silicone Co., Ltd.] can be used.

In the metal treating agent of the present invention, the mixing ratio of the components (A) and (B) is A: B = 90: 10 to 1: 1 when moisture resistance is required (in the copper foil, the S surface side). It can be used in the range of 99, preferably 75:25 to 1: 9
9 and when adhesiveness is required (in copper foil, M side), 60:40 to 1:99, preferably 50:50 to
It is 1:99. The coating thickness is not particularly limited, but when moisture resistance is required, it is usually 0.01 μm or more, preferably 0.1 μm or more.

The metal targeted by the metal surface treating agent of the present invention is not particularly limited. For example, it is useful as a surface treatment agent for copper, zinc and alloys thereof. However, it is suitable to be used as a surface treatment agent for copper, and particularly when used as a surface treatment agent for a copper foil used for a copper clad laminate for printed circuits, the effects of the present invention can be sufficiently exhibited. The copper foil includes a copper foil whose surface has been roughened, a copper foil which has been subjected to a brass layer formation treatment, a chromate treatment, a zinc-chromium group mixture coating treatment, and the like.

The surface-treating agent of the present invention may be directly applied to the metal surface as it is, but 0.001 to 0.001 of a solvent such as water, alcohol such as methanol and ethanol, and a solvent such as acetone, ethyl acetate and toluene. It is convenient and preferable to dilute the solution to 10% by weight, preferably 0.01 to 6% by weight, and apply the metal by dipping in the solution.
The mixture of the imidazolesilane compound and the bistrialkoxysilyl compound may be used alone, or may be used as a mixture of a plurality of compounds, and may be used as another rust preventive agent or a coupling agent. You may mix and use it.

[0020]

Example 1 Synthesis of imidazole silane compound (A-1) Imidazole and 3-glycidoxypropyltrimethoxysilane were reacted in the same manner as in Example 1 of Japanese Patent Application No. 4-183783 to give the following 3 A mixture of components [imidazole silane compound (A-1)] was obtained.

[0021]

[Chemical 4]

The mixed composition ratio of these is expressed by the formula (1-1):
(2-1) :( 3-1) = 45: 22: 33.

Preparation of Surface Treatment Agent (1) Bistrimethoxysilylethane was mixed with the mixture (A-1) of the above imidazole silane compound at various ratios to obtain a 6% concentration (total concentration, hereinafter the same) shown in Table 1. A methanol solution was prepared and used as a surface treatment agent (1).

Evaluation of Surface Treatment Agent (1) In order to evaluate the surface treatment agent (1) of the present invention, a sample was prepared as follows. Then, they were evaluated for moisture resistance.

Moisture resistance evaluation sample 2oz raw foil (4.5 × 4.5 cm) was ultrasonically cleaned with acetone for 5 minutes. Acetone is removed with water and 3% H ₂ SO ₄
After being washed with the aqueous solution for 1 minute, it was washed with water and then with acetone and dried with a dryer. The surface treatment agent (1) prepared as described above was applied to the S side of this copper foil by a spin coater 6
× 10 ^-4 g was applied (the film thickness when assuming a specific gravity of 1 is about 0.3 μm) to prepare a surface-treated foil.

Humidity resistance test The above-mentioned humidity resistance evaluation sample was left standing in a thermostat at 80 ° C. and 95% (relative humidity) for 24 hours, and the discoloration of the copper foil was visually evaluated. The results are shown in Table 1.

[0027]

[Table 1]

* Moisture resistance was evaluated according to the following criteria.

1: Discoloration to black brown 2: Discoloration to orange or yellow 3: Discoloration 4: Slight discoloration 5: No discoloration Example 2 Synthesis of imidazole silane compound (A-2) In the synthetic method, 2-ethyl-4-methylimidazole was used in place of imidazole, and components corresponding to the general formulas (1), (2) and (3) were similarly prepared except that the reaction temperature was 95 ° C. An imidazole silane compound (A-
2) was synthesized.

Preparation of Surface Treatment Agent The imidazolesilane compound (A-2) was mixed with bistrimethoxysilylethane at various ratios to prepare a 6% concentration methanol solution shown in Table 2.

Evaluation of Surface Treatment Agent (2) A moisture resistance sample was prepared in the same manner as in Example 1 using the surface treatment agent (2), and a moisture resistance test was conducted. The results are shown in Table 2.

[0032]

[Table 2]

* Moisture resistance evaluation is the same as in Table 1. Example 3Synthesis of imidazole silane compound (A-3) In the synthesis method of the above-mentioned imidazole silane compound (1)
2-undecylimidazole instead of imidazole
Using 3-glycidoxypropyltrimethoxysilane
Instead of 3-glycidoxypropyl dimethoxymethyl
The same procedure was used except that the orchid was used and the reaction temperature was 95 ° C.
Of the components corresponding to the general formulas (1), (2) and (3)
Combine the imidazole silane compound (A-3), which is a mixture,
I made it. Preparation of surface treatment agent (3) The above imidazole silane compound (A-3) has
Toxylsilylethane was mixed in various proportions and is shown in Table 3.
A 6% concentration methanol solution was prepared, and a surface treatment agent (3)
And

Evaluation of Surface Treatment Agent (3) A moisture resistance sample was prepared in the same manner as in Example 1 using the above treatment agent (3), and a moisture resistance test was conducted. The results are shown in Table 3.

[0035]

[Table 3]

* Moisture resistance evaluation is the same as in Table 1. Example 4Synthesis of imidazole silane compound (A-4) In the synthesis method of the above-mentioned imidazole silane compound (1)
2-undecylimidazole instead of imidazole
Using 3-glycidoxypropyltrimethoxysilane
Instead of 3-glycidoxypropylethoxydimethyl
The same procedure was used except that the orchid was used and the reaction temperature was 95 ° C.
Of the components corresponding to the general formulas (1), (2) and (3)
Combine the imidazole silane compound (A-4), which is a mixture,
I made it. Preparation of surface treatment agent (4) The above imidazole silane compound (A-4) has
Toxylsilylethane was mixed in various proportions and is shown in Table 4.
A 6% concentration methanol solution was prepared, and a surface treatment agent (4)
And

Evaluation of Surface Treatment Agent (4) A moisture resistance sample was prepared in the same manner as in Example 1 using the surface treatment agent (4), and a moisture resistance test was conducted. The results are shown in Table 4.

[0038]

[Table 4]

* Moisture resistance was evaluated in the same manner as in Table 1. Examples 5 to 8 Using the surface treatment agents (1) to (4) (however, 0.4% concentration) shown in Tables 1 to 4 below, The adhesiveness was evaluated as described above.

Adhesion Evaluation Sample 1oz JTC foil (having a zinc-chromium group mixture layer of zinc or zinc oxide and chromium oxide on the S side, and having the zinc-chromium group mixture layer on the M side via a brass layer). Foil; 25 ×
25 cm) on the M surface, a small amount of an aqueous solution (0.4% concentration) of the surface treating agent of the present invention adjusted to pH 5 with acetic acid was dropped, and S
A US roll was rolled and the treatment agent was applied. After application, 1
It was dried in an oven at 00 ° C for 5 minutes.

Adhesion Test The above-mentioned adhesion evaluation sample was hot pressed with a prepreg impregnated with an epoxy resin to prepare a copper clad laminate.
The copper foil side of this copper clad laminate was etched to form 0.2 mm width circuit × 10 pieces, and the peel strength was measured after soaking in boiling water for 2 hours, and the difference between the strength and the peel strength before boiling treatment was measured. Was obtained, and it was divided by the latter, and the obtained percentage was taken as the deterioration rate. The result is shown in FIG. In addition, FIG. 1 also shows the evaluation results of γ-glycidoxypropyltrimethoxysilane, imidazolesilane compound and bistrimethoxysilylethane as comparative examples.

[0042]

As described above, the treating agent of the present invention improves the moisture resistance of the S surface and is not oxidized even if it is stored in a high temperature / high humidity state for a long period of time. Also, on the M side, the adhesiveness with the resin is improved and the peel strength and deterioration rate after boiling can be reduced, so when mounted as a printed circuit board, for example, it does not peel even under high temperature and high humidity conditions Can be increased.

[Brief description of drawings]

FIG. 1 is a graph showing peel strength (deterioration rate) of a surface treating agent of the present invention after boiling.

Claims (1)

[Claims] 1. A novel imidazole silane compound (A) represented by the following general formulas (1), (2) and / or (3):
And a metal surface treatment agent containing a bistrialkoxysilyl compound (B) represented by the following general formula (4) as an active ingredient. [Chemical 1] (However, in the general formula (1), (2) or (3),
R ¹ is hydrogen or an alkyl group having 1 to 20 carbon atoms, R ² is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms, R ³ ,
R ⁴ is an alkyl group having 1 to 3 carbon atoms, n is 1 to 3) (R ⁵ O) ₃ SiR ⁶ Si (OR ⁵ ) ₃ (4) (wherein R ⁵ O is a lower one having 1 to 4 carbon atoms) An alkoxy group,
R ⁶ represents an alkylene group having 1 to 8 carbon atoms)