JP4841337B2 - Primer resin and resin composition for primer resin layer - Google Patents

Description

  The present invention provides a flexible printed wiring board such as a polyimide film substrate by using a copper foil obtained by thinly applying a benzotriazole type epoxy resin or a composition directly on the surface of the copper foil without subjecting the copper foil to a roughening treatment. It is related with the primer resin which can ensure favorable adhesiveness with the resin substrate for water, and the copper foil with a primer resin layer which consists of this primer resin.

Usually, a polyimide film is laminated with a metal foil (mainly copper foil) and used as a single-sided or double-sided flexible copper-clad laminate as a base resin film for flexible printed wiring boards or an interlayer insulating resin film for multilayer printed wiring boards. . Among them, the copper clad laminate called two-layer CCL is very useful in terms of miniaturization of wiring and heat resistance of the substrate, since the polyimide film and the copper foil are directly bonded without an adhesive layer. On the other hand, the adhesive strength between the polyimide film and the copper foil often becomes a problem. The two-layer CCL is manufactured by applying a polyimide precursor on a copper foil and heating it (Patent Document 1), as well as a lamination method (patent document 1) obtained by thermocompression bonding a thermoplastic polyimide film and a copper foil. There are methods such as literature 2) and a method in which a sputter layer is provided on the surface of a polyimide film and copper foil is plated, but the casting method is currently the mainstream.
On the other hand, as disclosed in many documents including Patent Document 1, a copper foil that has been used for manufacturing a conventional printed wiring board has a rough surface that forms irregularities by attaching fine copper particles to one surface thereof. Surface treatment is applied. When bonding with a base resin such as a prepreg, the uneven shape of the roughening treatment of the copper foil is embedded in the base resin to obtain an anchor effect, thereby improving the adhesion between the copper foil and the base resin. It has been obtained. However, since the surface of the copper foil is usually coated with an amine compound such as a rust inhibitor, a long-chain alkyl compound, or a silicone compound as a surface treatment agent, the two layers obtained by applying the polyimide precursor by the casting method as it is The peel strength of the CCL copper foil / polyimide resin decreases. Moreover, since the copper foil surface from which the surface treatment agent has been removed through complicated steps such as a degreasing step and soft etching is exposed to the air or a polyimide precursor, it is corroded and oxidized. Furthermore, untreated copper foil that has not undergone any surface treatment such as roughening treatment or rust prevention treatment is not only problematic in terms of adhesion strength, but it is technically difficult to improve the adhesion strength, and the primer resin is heat resistant. Although there is an example (Patent Document 5) using a conductive epoxy resin composition, no remarkable improvement is observed, and problems remain in adhesive strength and heat resistance.

Japanese Patent Publication No. 60-042817 Japanese Patent Publication No. 07-040626 Japanese Patent Publication No. 06-006360 Japanese Patent Publication No. 05-022399 JP 2003-304068 A

  If a copper foil that has not been roughened can be used in the production of a printed wiring board, the copper foil roughening treatment step can be omitted, and the production cost can be greatly reduced. Further, it is not necessary to provide an over-etching time for dissolving the roughened portion in circuit etching, and the total etching cost can be reduced.

  In addition, the use of copper foil that has not been subjected to roughening treatment for the printed wiring board makes it possible to form a finer wiring pattern by reducing the thickness of the roughened portion, and to reduce the electrical resistance of the wiring surface. Therefore, it is very useful, and if a copper foil that has not been subjected to a roughening treatment can be used in the production of a printed wiring board, it is preferable in terms of both reduction in production cost and improvement in performance.

  In the resin substrate for flexible printed wiring boards obtained by the casting method without roughening the copper foil, the present invention is a primer resin that can ensure good adhesion between the copper foil / polyimide resin, And it aims at providing the copper foil with a primer resin layer.

  In order to solve the above problems, the present inventors have completed the present invention as a result of intensive studies.

（式（１）中Ｒ_１はグリシジル基を含有する有機基を表し、Ｒ_２はグリシジル基を含有する１価の有機基またはＯ、Ｓ、Ｆ、Ｎを含んでもよい炭素数１〜６の有機基をそれぞれ表す。）で表されるベンゾトリアゾール型エポキシ樹脂からなるプライマー樹脂
（２）式（１）におけるＲ_１、Ｒ_２のうち少なくとも一方が、オキシグリシジル基である上記（１）記載のプライマー樹脂
（３）上記（１）または（２）に記載のプライマー樹脂が硬化剤および硬化促進剤を含有してなることを特徴とするプライマー樹脂層用樹脂組成物
（４）上記（１）もしくは（２）に記載のプライマー樹脂、または上記（３）記載のプライマー樹脂層用樹脂組成物がＮ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、ジメチルスルホキシド、メチルエチルケトン、メチルイソブチルケトンまたはメチルベンゾエートより選ばれる１種以上を含有する溶媒にさせ溶液を調製し、次いでこの溶液を銅箔上に塗布乾燥し、プライマー樹脂層を形成させることを特徴とする、プライマー樹脂層の形成方法
（５）上記（４）記載の形成方法により得られたプライマー樹脂層を備えたフレキシブルプリント配線板用の銅張り積層板
（６）粗面化処理の施されていない銅箔の表面粗さ（Ｒｚ）が２μｍ以下である面に上記（４）記載の形成方法により得られたプライマー樹脂層を備えていることを特徴とするプライマー樹脂層付銅箔
（７）プライマー樹脂層を設けた銅箔の表面が、ニッケル、鉄、亜鉛、金、錫より選ばれる１種以上のメッキ層を備えた面である上記（６）に記載のプライマー樹脂層付銅箔
（８）プライマー樹脂層を設けた銅箔またはメッキの表面が、シランカップリング剤層を備えた面である上記（６）または（７）に記載のプライマー樹脂層付銅箔
に関する。 That is, the present invention is (1) a resin for a primer resin layer for ensuring adhesion between a copper foil that has not been subjected to a roughening treatment and a resin base material, and the following formula (1)

(In formula (1), R ₁ represents an organic group containing a glycidyl group, and R ₂ is a monovalent organic group containing a glycidyl group, or O 1, S, F, or N, which may contain 1 to 6 carbon atoms. A primer resin composed of a benzotriazole type epoxy resin represented by formula (1), wherein at least one of R ₁ and R ₂ in formula (1) is an oxyglycidyl group; Primer resin (3) The primer resin according to (1) or (2) above contains a curing agent and a curing accelerator, and a resin composition for a primer resin layer (4) above (1) or The primer resin according to (2) or the resin composition for a primer resin layer according to (3) is N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide. A solution containing one or more selected from dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone or methyl benzoate is prepared, and then the solution is applied onto a copper foil and dried to form a primer resin layer. And a primer resin layer forming method (5) a copper-clad laminate for a flexible printed circuit board (6) provided with a primer resin layer obtained by the forming method described in (4) above (6) roughening treatment A copper foil with a primer resin layer (7), comprising a primer resin layer obtained by the forming method described in (4) above on a surface having a surface roughness (Rz) of 2 μm or less. ) The above (6), wherein the surface of the copper foil provided with the primer resin layer is provided with at least one plating layer selected from nickel, iron, zinc, gold, and tin. (8) The primer resin according to (6) or (7), wherein the surface of the copper foil or plating provided with the primer resin layer is a surface provided with a silane coupling agent layer. It relates to a copper foil with a layer.

  The primer resin of this invention is excellent in the adhesive strength to the copper foil which is an inorganic metal. It is also effective as a rust preventive agent without corroding the copper foil. Further, in the case of obtaining a resin film using a polyimide precursor solution in a copper-clad laminate for a flexible printed wiring board, the adhesive strength between the primer resin of the present invention and the polyimide resin film is also increased. Therefore, the primer resin and the copper foil with a primer resin layer of the present invention are extremely useful in the field of electrical materials such as electrical substrates.

  The primer resin of the present invention has the following formula (1)

If it is the benzotriazole type epoxy resin represented by these, there will be no restriction | limiting in particular. In formula (1), R ₁ represents an organic group containing a glycidyl group, and examples thereof include an oxyglycidyl group, a thioglycidyl group, an oxyperfluoroglycidyl group, a glycidylcarboxylate group, and a glycidylamino group. R ₂ represents a monovalent organic group containing a glycidyl group or an organic group having 1 to 6 carbon atoms which may contain O, S, F, and N. In addition to the organic group containing the glycidyl group, O, Examples of the organic group having 1 to 6 carbon atoms that may contain S, F, and N include, for example, a chain alkyl group such as methyl group, ethyl group, purpyl group, and butyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group. And a cyclic alkyl group such as trifluoromethyl group and hexafluoroethyl group, an alkoxy group such as methoxy group and ethoxy group, and a dialkylamino group such as dimethylamino group and diethylamino group. In the compound of the formula (1), a compound in which at least one of R ₁ and R ₂ is an oxyglycidyl group is preferable.

1 type or 2 types of compounds chosen from more are preferable.

  The primer resin of the present invention is usually represented by the following formula (3)

(In Formula (1), R ₃ represents an organic group having —OH, —SH, or —NH ₂ , and R ₂ represents an organic group having —OH, —SH, or —NH ₂ , or O, S, F, Each represents an organic group having 1 to 6 carbon atoms which may contain N.) and a reaction with epichlorohydrin. The reaction is usually carried out in a solvent containing one or more selected from N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, or methyl isobutyl ketone. it can.

  The reaction in the solvent is preferably carried out by adding 1.5 to 6 times excess epichlorohydrin to the reaction amount in a solution obtained by dissolving 20 to 80% by weight of the benzotriazole compound in the solvent, In order to neutralize the hydrogen chloride generated at this time, in addition to inorganic alkali components such as sodium hydroxide, potassium hydroxide and calcium hydroxide, basic organic compounds such as triethylamine and pyridine may be added. The amount added is preferably 1 to 1.5 molar equivalents relative to the amount of hydrogen chloride that can be generated. The reaction temperature is preferably 40 to 80 ° C. The reaction time is preferably 1 to 5 hours.

  After completion of the reaction, the insoluble matter such as generated hydrochloride can be removed by filtration, washing with water, etc., and after separation and washing, the primer resin of the present invention can be isolated.

  The resin composition for a primer resin layer of the present invention is not particularly limited as long as it contains a curing agent and a curing accelerator in addition to the benzotriazole type epoxy resin. Preferred curing agents include phenolic resins such as Kayahard GPH65 (hydroxyl equivalent: 203 g / eq, manufactured by Nippon Kayaku Co., Ltd.), Zylox XLC-3L (hydroxyl group equivalent: 173 g / eq, manufactured by Mitsui Chemicals), and Kayaflex CPAM-750 (hydroxyl equivalent: 5000 g / eq Nippon Kayaku Co., Ltd.), Kayaflex BPAM-250 (hydroxyl group equivalent 5000 g / eq Nippon Kayaku Co., Ltd.) and other reactive aromatic polyamide resins. The blending amount is preferably adjusted so that the equivalent of the curing agent is 1.2 times or less with respect to the epoxy equivalent of the primer resin. Further, as preferred curing accelerators, 2-methylimidazole (Cureazole 2MZ, manufactured by Shikoku Kasei Kogyo), 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Kasei Kogyo), 2-phenyl-4,5-dihydroxymethylimidazole Other than imidazole accelerators such as 2PHZ-PW (manufactured by Shikoku Kasei Kogyo) and phosphorus accelerators such as triphenylphosphine (TPP, manufactured by Hokuko Chemical) and tri-o-tolylphosphine (TOTP, manufactured by Hokuko Chemical) And microcapsule type latent curing accelerators such as EPCAT-P (active substance loading 20% by weight Nippon Kayaku) and EPCAT-PS5 (active substance loading 20% by weight Nippon Kayaku). The blending amount is preferably 0.2 to 2% by weight in the case of imidazole accelerators and phosphorus accelerators, and 1 to 10% by weight in the case of microcapsule type latent curing accelerators with respect to the primer resin.

  Various additives can be added to the primer resin composition of the present invention within a range that does not impair the adhesion strength of the resulting primer resin layer to the copper foil and polyimide resin and the rust preventive effect of the copper foil. Examples of these additives include organic additives such as polyimide resins, aromatic polyamide resins, epoxy resins and phenol resins, or inorganic additives such as silica compounds, pigments, dyes, antihalation agents, fluorescent whitening agents, interfaces. Activator, leveling agent, plasticizer, flame retardant, antioxidant, filler, antistatic agent, viscosity modifier, imidation catalyst, accelerator, dehydrating agent, imidization retarder, light stabilizer, photocatalyst, low Examples include dielectrics, conductors, magnetic substances, and thermally decomposable compounds.

The method for forming a primer resin layer of the present invention comprises a primer resin or a resin composition for a primer resin layer on one side of a copper foil that has not been subjected to a roughening treatment, and N-methyl-2-pyrrolidone, N, N-dimethylacetamide. , N, N-dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone or methyl benzoate is dissolved in one or more solvents, and this solution is used as a primer resin layer so that the thickness in terms of solid content becomes 1 to 10 μm It is a method of applying and drying. For example, a primer resin solution having a solid content of 20% by weight or a resin composition solution for a primer resin layer having a solid content of 20% by weight is applied to a thickness of 10 μm, and it is 5 to 60 minutes at 80 to 200 ° C., preferably 10 to 130 to 150 ° C. By drying for ˜30 minutes, a primer resin layer having a thickness of about 2 μm is obtained. Thus, the amount of the solvent used may be appropriately determined depending on the viscosity at the time of coating and the desired thickness of the primer resin layer, and the solid content (components other than the solvent) concentration in the solution is usually 5 to 50% by weight. , Preferably 10 to 30% by weight.
The heat source during drying may be hot air or a far-infrared heater, but hot air and a far-infrared heater may be used in combination from the standpoint of preventing solvent vapor from staying and conducting heat to the inside of the resin. The drying temperature is not particularly limited as long as it is a temperature necessary for removing the solvent (a temperature necessary for the curing reaction when a curing reaction between the primer resin and the curing agent is involved), and usually 80 to 200 ° C., preferably Is 120-180 ° C.

  A copper-clad laminate for a flexible printed wiring board comprising a primer resin or a primer resin layer mainly composed of a reaction product of a primer resin and a curing agent according to the present invention, the primer resin between the copper foil and the resin substrate. It is a copper-clad laminate for a flexible printed wiring board in which a layer is interposed, and the adhesive strength to both the copper foil and the resin substrate is preferably 1 N / mm.

  The copper foil with a primer resin layer of the present invention is a copper foil having a surface roughness (Rz) of 2 μm or less, which is not subjected to the roughening treatment used in the method for forming a primer resin layer, and the surface of the present copper foil. And a copper foil provided with one or more plating layers selected from nickel, iron, zinc, gold and tin, and / or a copper foil provided with a silane coupling agent layer.

  The plating layer on the surface of the copper foil is obtained by electrolysis or electroless plating in a solution in which one or more selected from nickel, iron, zinc, gold and tin are ionized, and the thickness is preferably 10 to 300 nm. The silane coupling agent that can be used is obtained by using various silane coupling agents (KBM series manufactured by Shin-Etsu Chemical Co., Ltd.) that are commercially available, such as amino-based, epoxy-based, etc., and the thickness is preferably 1 to 50 nm.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

In addition, the characteristic measuring method of the film in an Example is as follows.
(Measurement of adhesive strength with copper foil)
On the copper foil on which the primer resin layer is formed, the following formula (4)

(In formula (4), x is the number of repetitions, and the total weight average molecular weight is 81,000.) The polyimide precursor represented by the formula is dissolved in a mixed solvent of N-methyl-2-pyrrolidone and N, N-dimethylacetamide. KAYAFLEX KPI (polyimide precursor solution manufactured by Nippon Kayaku Co., Ltd.) is applied to a predetermined thickness, dried and then subjected to a heat ring closure reaction, and a 10 mm wide pattern is masked on the copper foil side of the obtained film with copper foil on one side. The film side was attached to a 0.3 × 70 × 150 mm iron plate (made by Cansuper Partec) with a bonding sheet, and the end of the 10 mm wide copper foil was peeled off from the resin with a cutter knife. Tensilon tester (A and D: (Orientec) was used to measure the adhesive strength between the copper foil and the resin in the 180 ° direction.

Synthesis Example 1
DAINSORB T-0 (2- (2,4-dihydroxyphenyl) -2H-benzotriazole), which is a benzotriazole compound, is attached to a 4-diameter flask equipped with a thermometer, a condenser, and a stirrer. Molecular weight 227.22 Hydroxyl equivalent 113.6 g / eq Daiwa Kasei) 113.6 g, epichlorohydrin 463 g and dimethyl sulfoxide (DMSO) 232 g were charged and dissolved at 50 ° C., and flaky sodium hydroxide (99% pure content) 42 g while introducing nitrogen gas with stirring. Was added in 2 hours. After the addition, the reaction was carried out at 60 ° C. for 1 hour, 70 ° C. for 1 hour, and 80 ° C. for 30 minutes. After completion of the reaction, 300 g of water and 30 g of a 30% aqueous solution of disodium hydrogen phosphate were added and washed with water, the aqueous layer was separated and removed, and the excess epichlorohydrin was distilled off under heating and reduced pressure. 420 g of methyl isobutyl ketone (MIBK) was then added to dissolve the residue.

  The methyl isobutyl ketone solution was heated to 70 ° C. and stirred, 7 g of a 30 wt% aqueous sodium hydroxide solution was added and reacted for 1 hour, followed by repeated washing with water to neutralize the pH. Further, the aqueous layer was separated and removed, and excess methyl isobutyl ketone was distilled off under reduced pressure by heating.

で表される黒色半固形のベンゾトリアゾール型２官能エポキシ樹脂（本発明のプライマー樹脂）１６１ｇを得た。エポキシ当量は１９２ｇ/ｅｑ、軟化点４９．７℃、１５０℃に於けるＩＣＩ粘度０．４Ｐａ・ｓであった。

161 g of a black semi-solid benzotriazole type bifunctional epoxy resin (primer resin of the present invention) represented by the formula: The epoxy equivalent was 192 g / eq, the softening point was 49.7 ° C., and the ICI viscosity was 0.4 Pa · s at 150 ° C.

Synthesis Example 2
DAINSORB T-1 (2-hydroxy-5-methylphenyl) -2H-benzotriazole, a benzotriazole compound, is attached to a 4-diameter flask equipped with a thermometer, a condenser, and a stirrer. Molecular weight: 225.25 Hydroxyl equivalent: 225.3 g / eq 225.3 g of Daiwa Kasei), 463 g of epichlorohydrin and 232 g of dimethyl sulfoxide (DMSO) were added and dissolved at 50 ° C. Further, 42 g of flaky sodium hydroxide (99% pure) was added while introducing nitrogen gas with stirring. Added over time. After the addition, the reaction was carried out at 60 ° C. for 1 hour, 70 ° C. for 1 hour, and 80 ° C. for 30 minutes. After completion of the reaction, 300 g of water and 30 g of a 30% aqueous solution of disodium hydrogen phosphate were added and washed with water, the aqueous layer was separated and removed, and the excess epichlorohydrin was distilled off under heating and reduced pressure. 600 g of methyl isobutyl ketone (MIBK) was then added to dissolve the residue.

  Further, this methyl isobutyl ketone solution was heated to 70 ° C., and 7 g of a 30% by weight sodium hydroxide aqueous solution was added and reacted for 1 hour with stirring, followed by repeated washing with water to neutralize the pH. Further, the aqueous layer was separated and removed, and the excess methyl isobutyl ketone was distilled off under reduced pressure by heating.

で表される黒色液状のベンゾトリアゾール型単官能エポキシ樹脂（本発明のプライマー樹脂）２７０ｇ得た。エポキシ当量は２９０ｇ/ｅｑ、１５０℃に於けるＩＣＩ粘度０．０５Ｐａ・ｓであった。

270 g of a black liquid benzotriazole type monofunctional epoxy resin (primer resin of the present invention) represented by The epoxy equivalent was 290 g / eq, and the ICI viscosity at 150 ° C. was 0.05 Pa · s.

Example 1
3.48 g of the benzotriazole type epoxy resin obtained in Synthesis Example 1 is dissolved in 50 g of N, N-dimethylformamide, and 30 g of Kayaflex CPAM-750 (hydroxyl group equivalent 5000 g / eq, manufactured by Nippon Kayaku Co., Ltd.) is used as a curing agent. Then, 0.035 g of 2PHZ-PW (imidazole accelerator Shikoku Kasei) was added as a curing accelerator and dissolved by stirring to obtain a solution of the resin composition for a primer resin layer of the present invention. The solution viscosity measured with an E-type viscometer was 15000 mPa · s at 25 ° C.

Example 2
50 g of the primer resin composition solution obtained in Example 1 was added with 50 g of N, N-dimethylformamide for dilution, and the surface roughness (Rz) of 17 μm was obtained using an automatic applicator (manufactured by Yasuda Seiki Seisakusho). After apply | coating by 10 micrometers thickness on the rolled copper foil which is 2 micrometers or less, it dried at 130 degreeC * 10 minutes, and obtained the copper foil with a primer resin layer of 1.4 micrometers thickness of this invention.

Example 3
Using a solution obtained by dissolving 5 g of the benzotriazole type epoxy resin obtained in Synthesis Example 1 in 45 g of N, N-dimethylformamide, using an automatic applicator (manufactured by Yasuda Seiki Seisakusho), the surface roughness (Rz) of 17 μm thickness is 2 μm. It apply | coated by 25 micrometers thickness on the following rolled copper foil, Then, it dried at 130 degreeC * 10 minutes, and obtained the copper foil with a primer resin layer of 2.3 micrometers thickness of this invention.

Example 4
In the same manner as in Example 3 except that the benzotriazole type epoxy resin obtained in Synthesis Example 2 was used instead of the benzotriazole type epoxy resin of Synthesis Example 1 used in Example 3, 2 of the present invention was used. A copper foil with a primer resin layer having a thickness of 2 μm was obtained.

Example 6
Instead of the rolled copper foil having a surface roughness (Rz) of 17 μm thickness of 2 μm or less used in Example 2, a copper foil having a nickel plating layer of 170 nm thickness on the copper foil was used. In the same manner as in Example 2, a nickel-plated copper foil with a primer resin layer having a thickness of 1.4 μm according to the present invention was obtained.

Example 7
Instead of the benzotriazole type epoxy resin of Synthesis Example 1 used in Example 2, the benzotriazole type epoxy resin obtained in Synthesis Example 2 was used, and the surface roughness (Rz) of 17 μm thickness was 2 μm. The 1.4 μm-thick primer resin of the present invention was used in the same manner as in Example 2 except that instead of the rolled copper foil, a copper foil having a 170-nm-thick nickel plating layer formed thereon was used. A nickel-plated copper foil with a layer was obtained.

Example 8
After applying KAYAFLEX KPI (polyimide precursor solution made by Nippon Kayaku Co., Ltd.) with an automatic applicator (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) to the primer resin layer side of the copper foil with the primer resin layer obtained in Example 2, Dry at 130 ° C. for 10 minutes, then raise the temperature to 350 ° C. in a nitrogen atmosphere over 2 hours, hold at 350 ° C. for 2 hours, and then cool to room temperature for the flexible printed wiring board of the present invention. A copper clad laminate was obtained. The resin layer was 12 μm thick.

Example 9
Using the copper foil with primer resin layer obtained in Example 3, a copper-clad laminate for a flexible printed wiring board of the present invention was obtained in the same manner as in Example 8. The resin layer was 15 μm thick.

Example 10
Using the copper foil with a primer resin layer obtained in Example 4, a copper-clad laminate for a flexible printed wiring board of the present invention was obtained in the same manner as in Example 8. The resin layer was 13 μm thick.

Example 12
Using the nickel-plated copper foil with primer resin layer obtained in Example 6, a copper-clad laminate for a flexible printed wiring board of the present invention was obtained in the same manner as in Example 8. The resin layer was 12 μm thick.

Example 13
Using the nickel-plated copper foil with primer resin layer obtained in Example 7, a copper-clad laminate for a flexible printed wiring board of the present invention was obtained in the same manner as in Example 8. The resin layer was 14 μm thick.

Comparative Example 1
Observation of the difference in surface condition between immediately after exposure to the atmosphere and after exposure for one week without providing a primer resin layer on a rolled copper foil with a surface roughness (Rz) of 17 μm or less. did.

Comparative Example 2
Without providing a primer resin layer on a rolled copper foil having a surface roughness (Rz) of 17 μm or less, a KAYAFLEX KPI-100 (polyimide precursor solution manufactured by Nippon Kayaku Co., Ltd.) and an automatic applicator (manufactured by Yasuda Seiki Seisakusho) ) And then dried at 130 ° C. for 10 minutes, then heated to 350 ° C. over 2 hours under a nitrogen atmosphere, further maintained at 350 ° C. for 2 hours, and then allowed to cool to room temperature. Thus, a copper-clad laminate for the flexible printed wiring board of the present invention was obtained. The resin layer was 11 μm thick.

The surface states of the copper foils of Examples 2 to 4, 6, 7 and Comparative Example 1 are shown in Table 1, and the results of the adhesive strength measurement values of Examples 8 to 10, 12, 13 and Comparative Example 2 are shown in Table 2. .

Claims (6)

(A) The following formula (1)

(In formula (1), R1 represents an organic group containing a glycidyl group, and R2 represents an organic group containing a glycidyl group or an organic group having 1 to 6 carbon atoms that may contain O, S, F, and N, respectively. .)
A primer resin comprising a benzotriazole type epoxy resin represented by: or (b) a resin composition for a primer resin layer comprising the primer resin, a curing agent and a curing accelerator,
A solution is prepared by dissolving in a solvent containing one or more selected from N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone or methyl benzoate. Then, this solution is applied and dried on a copper foil for a flexible printed wiring board which has not been subjected to a roughening treatment, thereby forming a primer resin layer. The method for forming a primer resin layer according to claim 1, wherein at least one of R1 and R2 in formula (1) is an oxyglycidyl group. The copper clad laminated board for flexible printed wiring boards provided with the primer resin layer obtained by the formation method of Claim 1 or 2. The primer foil obtained by the forming method according to claim 1 or 2 is provided on the surface where the surface roughness (Rz) of the copper foil not subjected to the roughening treatment is 2 μm or less. Copper foil with primer resin layer. The copper foil with a primer resin layer according to claim 4, wherein the surface of the copper foil provided with the primer resin layer is a surface provided with at least one plating layer selected from nickel, iron, zinc, gold, and tin. 6. The copper foil with a primer resin layer according to claim 4, wherein the surface of the copper foil or plating provided with the primer resin layer is a surface provided with a silane coupling agent layer.