JP2002019021A - Copper foil having polyallylamine coating layer and copper-clad laminated plate for printed wiring board using the copper foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide copper foil which keeps good resistance to oxidative discoloration and high peel strength in a copper-clad laminated plate obtained by laminating a resin base material on the adhesive surface of the copper foil. SOLUTION: A coat layer of polyallylamine is formed at least on one side of the copper foil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copper foil having a polyallylamine coating layer and a copper-clad laminate for a printed wiring board using the same. More specifically, a copper foil which is excellent in the oxidation discoloration resistance of a copper foil during storage and which has excellent adhesion between a copper foil and a resin substrate after being made into a copper-clad laminate, and a copper-clad for a printed wiring board using the same. It relates to a laminate.

[0002]

2. Description of the Related Art In printed wiring boards, miniaturization, higher performance, and higher reliability of electronic components and the like incorporated therein have been progressing, and accordingly, copper foil, which is a constituent material of printed wiring boards, has various properties. Is required. For example, when the copper foil is an electrolytic copper foil, the side of the copper foil surface called the M surface (mat surface or roughened surface) mainly has adhesiveness to the base material, chemical resistance, and the like, The opposite side, which is generally called the S-side (shiny surface or glossy surface), is mainly required to have oxidation resistance, moisture resistance, and the like. It is also required that both the M surface and the S surface have no oxidation discoloration of the copper foil during storage. In response to these requirements, for example, a brass layer is formed on the copper foil surface (JP-B-51-35711), a chromate layer is formed (JP-B-62-14040), or zinc or zinc oxide and chromium oxide are formed. It is known to perform a coating treatment with a zinc-chromium mixture (Japanese Patent Publication No. 58-7077). A method of applying a silane coupling agent has also been proposed as a means for increasing the adhesion (peeling strength) to a substrate (Japanese Patent Publication No. 60-1565).
No. 4, JP-A-10-22609). Even with these copper foils having a surface treatment layer, a copper foil that simultaneously satisfies both the properties of adhesiveness and oxidation discoloration resistance has not been obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a copper foil having a polyallylamine coating layer on at least one side thereof, so that the copper foil has a high resistance to oxidation and discoloration and has a high coating strength. An object of the present invention is to provide a copper foil capable of maintaining a high peeling strength between a copper foil and a resin substrate when a bonding surface and a resin substrate are laminated to form a copper-clad laminate. Another object of the present invention is to provide a copper foil having the above properties without using harmful hexavalent chromium. Another object of the present invention is to provide a copper-clad laminate for a printed wiring board having excellent peel strength between a copper foil and a resin substrate using the copper foil.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the surface of a copper foil has
By providing a coating layer made of polyallylamine,
The present inventors have found that a copper foil having excellent oxidation discoloration resistance can be obtained, and have completed the present invention based on this finding. That is, the present invention provides a copper foil having a coating layer made of polyallylamine on at least one surface of the copper foil.

[0005] The present invention also provides a copper-clad laminate for a printed wiring board in which the above-mentioned copper foil is bonded to a substrate.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The copper foil of the present invention is suitably used, for example, as a copper foil for printed wiring boards. The copper foil of the present invention is, for example, coated on at least one surface of the copper foil with an aqueous solution containing polyallylamine at a concentration of preferably 0.001 to 10 g / l, more preferably 0.01 to 5 g / l, and heating. It can be manufactured by drying. Polyallylamine is a linear olefin-based polymer containing only a primary amino group (—NH ₂ ) in a side chain, and is positively charged in water, and is used in many applications as a water-soluble polycation. In a fibrous material, a polyallylamine coating layer is formed for the purpose of improving the fixing property of a dye and the adhesiveness of a coating film (for example, JP-B-61-011349, JP-B-63-0315).
No. 95, JP-A-02-080681, JP-A-04-240270), and such a treatment has been attempted for a copper foil such as a copper foil for a printed wiring board in order to improve the adhesiveness to a resin base material. Never been. As the polyallylamine used in the present invention, specifically, a compound represented by the following formula is suitably used.

[0007]

Embedded image

In the formula, n is a positive number representing the degree of polymerization. Polyallylamine has a weight average molecular weight Mw of 800 to 10
000 is preferred, and 1,000 to 50,000
0 is more preferred. The copper foil used in the present invention may be either an electrolytic copper foil or a rolled copper foil, and is preferably used for a copper-clad laminate for a printed wiring board, and is not particularly limited. A surface treatment layer may be provided in advance on the surface of the copper foil. As such a surface treatment, a roughened layer in which a small spherical copper electrodeposit is formed using a copper sulfate plating solution, a Ni-Mo-Co alloy layer, an In-Z
n-alloy layer and the like. Although the thickness of the copper foil is not particularly limited, a thickness of 9 to 70 μm is usually used. As described above, polyallylamine was added to the surface of the copper foil by 0.0
A coating layer made of polyallylamine is formed by applying a polyallylamine aqueous solution containing the polyallylamine at a concentration of 01 to 10 g / l and drying by heating. The thickness of the coating layer composed of polyallylamine varies depending on the molecular weight, concentration, and coating amount of polyallylamine contained in the aqueous solution.
The angle is preferably set to 00 °, more preferably 10 to 100 °. If the coating layer made of polyallylamine is too thin, the oxidation discoloration resistance (S plane or M plane) and the peel strength (M plane) tend to decrease. If the coating layer made of polyallylamine is too thick, coating unevenness tends to occur, and it is uneconomical.

The method for applying the aqueous solution containing polyallylamine to the surface of the copper foil is not particularly limited.
It can be easily performed by a method such as a spray method or an immersion method. The coating amount is preferably 0.5 to 50 g / m ² , and the coating processing time is usually within 30 seconds, preferably 1 to 1
It is applied to the surface to be bonded of the copper foil in 5 seconds.

[0010] The copper foil coated with the aqueous solution is immediately dried, preferably in a hot air drier at 50 to 120 ° C, preferably 1 to 5 ° C.
By sufficiently drying for a minute, a copper foil having a coating layer made of polyallylamine on the surface to be bonded of the copper foil is obtained.

The copper foil obtained according to the present invention is laminated and formed on a resin-impregnated base material as a copper foil for a printed wiring board in the production of various copper-clad laminates, for example. Examples of the resin of the resin-impregnated base include thermosetting resins such as epoxy resin, phenol resin, polyimide, unsaturated polyester resin, and silicon resin, and thermoplastic resins such as polyethylene, saturated polyester, and polyether sulfone. Examples include paper, glass fiber nonwoven fabric, glass fiber woven fabric, and the like. Further, a polyimide film, a polyester film, or a substrate made of a metal plate such as aluminum or iron may be bonded with an adhesive.

[0012]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples of the present invention and Comparative Examples thereof, but the present invention is not limited to these Examples.

Example 1 A 1 μm-thick roughened layer of small spherical copper electrodeposits was formed on the M-face side of a 35 μm-thick electrolytic copper foil using a copper sulfate plating solution. After washing the copper foil with water, 1 g / l of polyallylamine prepared using PAA-01 (polyallylamine (trade name, manufactured by Nitto Boseki Co., Ltd., weight average molecular weight: about 1,000, concentration: 15% by weight, specific gravity: 1.02)) PH containing
9. An aqueous solution having a temperature of 25 ° C. was applied to the M and S surfaces by a spray method for 5 seconds so that the application amount was 2.5 g / m ² . Immediately after the treatment, the coating was dried for 5 minutes in a hot-air drier set at a temperature of 100 ° C. to form a coating layer (thickness: 25 °) made of polyallylamine on both surfaces of the copper foil.

The obtained copper foil was cut into a length of 10 cm and a width of 10 cm, and 20 sheets were piled up and subjected to the following life cycle test. The results are collectively shown in Table 1. Life cycle test conditions One cycle is 12 hours (1 cycle: 20% at 85% humidity)
Temperature from 60 ° C to 60 ° C over 2 hours,
, And the temperature was lowered from 60 ° C. to 20 ° C. over 2 hours, and maintained at 20 ° C. for 3 hours). After 4 cycles and 8 cycles, the discoloration of the copper foil surface was visually observed. , ○: No discoloration, Δ: Slight discoloration, × ・ ・
-Oxidation discoloration resistance was evaluated as marked discoloration. Also,
The adhered surface side of the obtained copper foil is overlapped with an epoxy resin impregnated glass cloth substrate (ANSI grade FR-4) and
Heat and pressure treatment was performed at a temperature of 168 ° C. and a pressure of 2.94 MPa for 60 minutes to produce a copper-clad laminate having a length of 25 cm, a width of 25 cm and a thickness of 1.6 mm. The copper-clad laminate was subjected to a normal-state peeling test (peeling width: 1 mm, JIS-C-6481, unit: kN / m). The results are shown in Table 1 collectively.

Examples 2 to 6 Using the same copper foil as in Example 1, a roughened layer similar to that of Example 1 was formed, washed with water, and then subjected to PAA-03 (polyurethane manufactured by Nitto Boseki Co., Ltd.). Allylamine trade name, weight average molecular weight about 3,000, concentration 20% by weight, specific gravity 1.03), PAA
-05 (trade name of polyallylamine manufactured by Nitto Boseki Co., Ltd., weight average molecular weight about 5,000, concentration 20% by weight, specific gravity 1.
03), PAA-10C (Polyallylamine trade name, manufactured by Nitto Boseki Co., Ltd., weight average molecular weight: about 15,000, concentration: 1)
A polyallylamine coating layer (outermost layer) was formed using an aqueous solution of polyallylamine having a predetermined concentration prepared using 0% by weight and a specific gravity of 1.01), and dried. The obtained copper foil was used as the same copper-clad laminate as in Example 1, a test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results.

Example 7 Using the same copper foil as in Example 1, the same roughening treatment layer as in Example 1 was further coated with the following bath composition and electrolytic conditions.
After forming an i-Mo-Co alloy layer and washing with water, a polyallylamine coating layer (outermost layer) was used using an aqueous solution shown in Table 1.
Was formed and drying was performed. The obtained copper foil was used as a copper-clad laminate in the same manner as in Example 1, a test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results. Bath composition Trisodium citrate dihydrate 30 g / l Nickel sulfate hexahydrate 8 g / l Sodium molybdate dihydrate 3 g / l Cobalt sulfate hexahydrate 28 g / l pH 6.2 Bath temperature 30 ℃ Electrolysis condition Current density 3A / dm ² Electrolysis time 4sec

Example 8 Using the same copper foil as in Example 1, the same roughening treatment layer as in Example 1 was further applied to the same bath composition and electrolytic conditions as shown below.
After forming an n-Zn alloy layer and washing with water, a polyallylamine coating layer (outermost layer) was formed using an aqueous solution shown in Table 1, and drying was performed. The obtained copper foil was used as the same copper-clad laminate as in Example 1, a test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results. Bath composition Indium sulfate xhydrate 0.5 g / l Zinc sulfate heptahydrate 5.0 g / l pH 3.0 Bath temperature 30 ° C Electrolysis conditions Current density 0.3 A / dm ² Electrolysis time 3 seconds

Comparative Example 1 Using the same copper foil as in Example 1, a roughened layer similar to that of Example 1 was formed, and a polyallylamine coating layer was not formed. , A test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results.

Comparative Example 2 Using the same copper foil as in Example 1, a 1 g / l γ-glycidoxypropyltrimethoxysilane solution was applied onto the roughened layer as in Example 1, A copper-clad laminate was prepared in the same manner as in Example 1 except that the silane coupling agent layer was formed in place of the allylamine coating layer, and a test piece was prepared in the same manner as in Example 1. The test was performed. Table 1 shows the evaluation results.

Comparative Example 3 Using the same copper foil as in Example 1, a chromate layer was formed on a roughened layer similar to that of Example 1 with the following bath composition and electrolysis conditions instead of the polyallylamine coating layer. Was formed into a copper-clad laminate in the same manner as in Example 1, a test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results. Bath composition Sodium dichromate dihydrate 5 g / l pH 4.7 Bath temperature 30 ° C Electrolysis conditions Current density 0.5 A / dm ² Electrolysis time 5 seconds

COMPARATIVE EXAMPLE 4 Using the same copper foil as in Example 1, the same bath composition and electrolytic conditions as in Comparative Example 3 were applied on the roughened layer similar to that of Example 1 instead of the polyallylamine coating layer. To form a chromate layer,
After washing with water, a copper-clad laminate was produced in the same manner as in Example 1 except that the same silane coupling agent layer coating layer as in Comparative Example 2 was formed, and a test piece was produced in the same manner as in Example 1. A similar property test was performed. Table 2 shows the evaluation results.

COMPARATIVE EXAMPLE 5 Using the same copper foil as in Example 1, on the roughened layer similar to that in Example 1, a Zn-Co alloy was used instead of a polyallylamine coating layer under the following bath composition and electrolytic conditions. Except for the formation of the Cr layer, a copper-clad laminate was prepared in the same manner as in Example 1, a test piece was prepared in the same manner as in Example 1, and the same characteristic test as in Example 1 was performed. Table 1 shows the evaluation results. Bath composition Sodium dichromate dihydrate 1 g / l Zinc sulfate heptahydrate 10 g / l Caustic soda 40 g / l pH 13 Electrolysis conditions Current density 1.0 A / dm ² Electrolysis time 3 seconds

[0023]

[Table 1]

[0024]

The copper foil having a polyallylamine coating layer obtained according to the present invention is obtained by laminating a resin substrate on the surface to be adhered of the copper foil to form a copper-clad laminate. , While maintaining a high peeling strength, and exhibiting no oxidation discoloration resistance without any discoloration even when exposed to a high-temperature, high-humidity atmosphere for a long time. Further, since the copper foil of the present invention can be manufactured without using a harmful hexavalent chromium compound, there is no possibility of causing a problem of contamination of a working environment. Furthermore, there is no problem in terms of management in production, and the industrial value is extremely large.

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Claims (2)

[Claims] 1. A copper foil comprising a coating layer made of polyallylamine on at least one surface of the copper foil. 2. A copper-clad laminate for printed wiring boards, wherein the copper foil according to claim 1 is bonded to a substrate.