JPH0528835A - Filmy copper-evaporated base material - Google Patents

Abstract

PURPOSE:To equip a base material for Cu evaporative attachment made from a plastic film with a sufficient flexibility, good tight attachment resisting against bending, and a good durability by forming a bridged resin primer layer, a Cu- evaporated layer, and a rust preventive agent layer chiefly containing benzoazole compound on the base material one over another. CONSTITUTION:A bridged resin primer layer consisting of polyester type bridged resin, a Cu-evaporated layer, and a rust-preventive agent layer chiefly containing benzoazole compound are formed one over another on a base material made from a plastic film. The exfoliation strength of these primer layer and Cu- evaporated layer hall be 5g/mm or more, and the benzoazole compound be benzoazole and/or its amine salt with water solubility. Thereby the Cu- evaporated layer, which is thin and maintains sufficient flexibility, is equipped with good tight contacting resisting against bending and also with good anti- corrosiveness.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to copper vapor deposited substrates suitable for use as substrates for electronic circuits, especially flexible printed circuits.

[0002]

2. Description of the Related Art Conventionally, as a flexible printed circuit board, generally used is a copper foil having a thickness of about 10 μm to 100 μm attached to a synthetic resin film substrate with an adhesive. A circuit pattern is formed on the copper foil surface of this substrate by screen printing or a photoresist method, and then the copper foil in the non-circuit portion is dissolved and removed by a wet etching method using an etching solution such as ferric chloride to make it flexible. A printed circuit is obtained.

However, since the copper foil has a thickness of 10 to 100 μm, not only the flexibility of the obtained flexible substrate is deteriorated, but also the copper foil is peeled off from the resin film substrate by bending. Therefore, it may be unsuitable for applications requiring great flexibility (for example, contact circuits of electronic desk calculators). Furthermore, in order to etch a thick copper foil, a large amount of time and an etching solution are required, so not only the cost becomes high, but also side etching causes a problem that the dimensional accuracy is lowered. In order to solve these problems, efforts have been made to reduce the thickness of the copper foil, but if the copper foil used is thin, pinholes will occur and it will not be used as an electronic circuit, or copper rolling technology Since there are some problems, the practical lower limit of about 10 to 20 μm is the lower limit of the practical thickness of the copper foil, and the above problems cannot be solved.

In order to eliminate the above-mentioned problems of a flexible printed circuit board using a copper foil, a copper deposition layer is formed on a resin substrate instead of the copper foil to form a copper deposition base material for a flexible printed circuit. It has also been proposed (Japanese Patent Application Laid-Open No. 59-113040, Japanese Patent Publication No. 61-19707).
No. 6-183460, etc.) have hardly been put to practical use. This is because the copper deposition layer, which is formed by the generally expensive thin film deposition process of vapor deposition (including more expensive sputtering or ion plating in addition to normal vacuum deposition), can compete costly with copper foil. However, if the thickness of such a thin copper deposition film is left to stand naturally, it will easily change to hydroxide or oxide due to moisture or oxygen in the air, and electrical conductivity This is because the degree of deterioration is reduced and the electronic circuit is not suitable. Therefore, the copper vapor-deposited base material is stored and transported together with a desiccant (for example, silica gel) in a high-barrier film bag having small moisture permeability and oxygen permeability so as not to cause the above-mentioned deterioration. Under such conditions, only a small amount is used. In order to solve the problem of deterioration of the copper vapor-deposited layer, another metal vapor-deposited layer such as Ni having good corrosion resistance may be provided on the copper vapor-deposited layer (Japanese Patent Laid-Open No. 62-181488), or a wet method may be used. Copper plated to a total thickness of 5
It has also been proposed to increase the thickness to about μm (Japanese Patent Laid-Open No. 6-58242).
2-70029). However, these are also uneconomical with additional steps.

Therefore, in spite of the above-mentioned many problems, the copper foil is predominantly used in the conventional flexible printed circuit board.

[0006]

In view of the above-mentioned facts, the present invention uses a conventional copper foil by providing a reliable copper vapor deposition substrate by preventing the problem of alteration of the copper vapor deposition layer. The purpose of the present invention is to solve the problems of the base material.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted research for the above-mentioned purpose, and found that a benzazole compound in a copper rust inhibitor, which has been known per se from the past, was formed in a copper vapor-deposited layer. When applied, it does not cause deterioration of electrical properties and exhibits a considerable effect in preventing its deterioration; the deterioration of the copper vapor deposition layer does not occur only from its surface layer, but also from the synthetic resin film substrate side. And that the alteration of the copper vapor-deposited layer from the side of the substrate can be significantly prevented by providing a proper primer layer between the substrate and the copper-deposited layer; and by selecting an appropriate primer layer, there is considerable bending. It was found that the adhesion strength between the copper vapor-deposited layer and the substrate, which can sufficiently withstand the use, can be obtained.

That is, the film-form copper vapor-deposited substrate of the present invention is based on such knowledge, and contains a crosslinked resin primer layer, a copper vapor-deposited layer and a benzazole compound as a main component on a synthetic resin film substrate. It is characterized in that a rust preventive agent layer is sequentially formed.

The constitution of each part of the copper vapor deposition substrate of the present invention will be described in detail below.

The synthetic resin film substrate constituting the copper vapor-deposited substrate of the present invention has a slight rigidity in addition to a film or sheet made of synthetic resin such as polyethylene terephthalate film, polyimide film, polyamide film, polyphenylene sulfide film. Reinforced glass cloth reinforced epoxy resin film or sheet,
Aramid paper, etc. has its electrical insulation, heat resistance,
It is preferably used because of its chemical resistance and mechanical properties. Of these, a polyethylene terephthalate film is preferable from the viewpoint of the above characteristics and economy. The thickness of the synthetic resin film substrate is basically not particularly limited, but from the viewpoint of mechanical strength, flexibility, etc., it is generally preferably in the range of 10 to 100 μm.

The cross-linking primer resin for forming the copper vapor-deposited surface is an essentially cross-linking primer resin such as unsaturated polyester resin, polyfunctional acrylic resin, melamine resin and polyurethane resin, which are generally known as thermosetting or UV-curing resins. A resin, or a cured product of a crosslinkable resin obtained by mixing the crosslinkable resin with a saturated polyester resin, an acrylic resin or the like is used. These crosslinked primer resin layers form a dense vapor-deposited surface by themselves and have excellent adhesion to the copper vapor-deposited layer formed due to less shrinkage in the vapor-deposition process, and thus contribute to prevention of alteration of the copper vapor-deposited layer. It is considered that

According to the studies by the present inventors, among others, a primer layer made of a cured product of a polyester-based crosslinkable resin obtained by introducing a crosslinkable component into a saturated polyester resin has good adhesion to a copper vapor deposition layer. Is most preferable in giving. The saturated polyester resin as the main component is generally composed of one or more aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid and naphthalene dicarboxylic acid and aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid and sebacic acid. Dicarboxylic acid and one or more glycols or polyhydric alcohols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane and pentaerythritol. A saturated polycondensation product,
As a measured value at 30 ° C. in a mixed solvent of phenol / tetrachloroethane = 60/40 (weight ratio), 0.2-1.
Those having a molecular weight corresponding to an intrinsic viscosity [η] of 5 dl / g, particularly 0.4-0.7 dl / g are preferable. In order to improve the adhesion to the copper vapor-deposited layer, the polyester main chain or side chain has a sulfonic acid metal salt (alkali metal salt, alkaline earth metal salt, etc.) group (for example, SO ₃ Na group),
Alternatively, it is preferable to introduce a tertiary amine group and adjust the SP (solubility constant) value to 8 to 12, particularly 9 to 10.

In order to provide the above-mentioned saturated polyester resin with improved adhesion to the vapor-deposited copper layer, the crosslinkable component used together with it is a melamine resin, which is often used in combination with an active hydrogen compound. Functional isocyanate compound; divalent or higher metal compound such as zinc, magnesium and aluminum used in combination with free carboxyl group-containing polyester; or various (meth) acrylate, hydroxy (meth) acrylate, (meth) acrylic acid, epoxy ( Examples thereof include compounds having one or more polymerizable unsaturated bonds in the molecule such as a (meth) acrylate compound. These crosslinkable components have the effect of significantly improving the adhesion to the copper vapor deposition layer even in an extremely small amount, and the range of 0.1 to 110 parts by weight, particularly 1 to 80 parts by weight, per 100 parts by weight of the saturated polyester resin is preferable. It is preferably used.
However, the compound having a polymerizable unsaturated bond may be used in an amount of 20 to 500 parts by weight with respect to 100 parts by weight of the saturated polyester resin, 10% by weight or more of which has two or more unsaturated bonds, Alternatively, it preferably has an ester-forming hydroxy group, carboxy group, or epoxy group in addition to one or more unsaturated bonds.

The polyester-based crosslinkable resin further comprises a crosslinking accelerator such as phosphoric acid, a tin compound, a peroxide and a photosensitizer, an antioxidant, a surfactant, and a workability depending on the crosslinkable component. Conventional additives such as lubricants for improvement are added as needed.

The above polyester-based crosslinkable resin provides a crosslinked resin primer layer having particularly excellent adhesion to a polyethylene terephthalate (PET) film substrate, and both can be said to be one of the most preferable combinations.

The crosslinkable resin (composition) as described above is
Depending on the system, undiluted, as an organic solvent or aqueous solution, or as a water-emulsion, it is applied on a synthetic resin film substrate, dried if necessary, and then cured by heating or UV irradiation to give a crosslinked resin primer. Form the layers. For example, in the case of a polyester-based crosslinkable resin containing a heat-crosslinkable resin such as melamine resin as a crosslinking component,
It is preferable to heat and crosslink in the range of 180 ° C. 1
If the temperature is lower than 40 ° C., the crosslinking becomes insufficient, and if the temperature exceeds 180 ° C., wrinkles are generated due to the shrinkage depending on the synthetic resin film substrate material, and stable vapor deposition becomes difficult.

The thickness of the primer layer is 0.5 μm to 4 μm.
The range is preferably m, more preferably 1 to 2 μm. When the thickness is less than 0.5 μm, the adhesion with the copper vapor deposition layer becomes non-uniform due to coating unevenness. If the thickness exceeds 4 μm, it becomes difficult to sufficiently crosslink the resin.

A copper vapor deposition layer is formed on the crosslinked primer layer formed as described above. The copper vapor deposition can be carried out by a method generally known to give good adhesion to a plastic substrate, such as sputtering or ion plating, but in the present invention, it is already formed by forming a crosslinked primer layer thereon. Since the adhesiveness with the copper vapor deposition layer is secured, it is preferable to perform the vacuum vapor deposition method in the narrower sense, which is more economical. As the copper to be used, ordinary electrolytic copper (purity 99% or more) is used, but as described in Japanese Patent Publication No. 61-19707, it has a higher melting point than copper for the purpose of preventing bumping, and the vapor deposition temperature. A metal having a vapor pressure smaller than that of copper and more easily oxidized than copper, such as Ti or Si, can be added to the same crucible up to 1.5% by weight of copper.

The copper vapor deposition layer is preferably formed to a thickness in the range of 0.05 to 10 μm, particularly 0.1 to 3 μm. If the thickness is less than 0.05 μm, the conductivity required for forming an electronic circuit cannot be secured, and pinholes may occur.
On the other hand, it is uneconomical to form a copper vapor deposition layer having a thickness of more than 10 μm.

The copper vapor-deposited layer thus formed has good adhesion to the crosslinked resin primer layer. Such good adhesion is judged by a cross-cut peel test using a polyester adhesive tape (No. 31C manufactured by Nitto Electric Industry Co., Ltd.). Cross-cut peeling test (JIS D0202 coating film test) applies to 11 vapor-deposited layers reaching the substrate or primer layer surface (interval 1 m
m) The cuts were made orthogonal to each other to form 100 square cells of 1 mm x 1 mm, and after the adhesive tape was attached to the square, the adhesive tape was peeled off vigorously to determine the number of remaining vapor-deposited layer squares. The degree of adhesion determines the degree of adhesion between the vapor deposition layer and the substrate or primer layer. Conventionally, cellophane tape (No. 405 manufactured by Nichiban Co., Ltd.) was generally used as the above-mentioned adhesive tape for evaluating the adhesion of the vapor deposition layer, but for flexible printed circuits exposed to repeated bending. In the base material, even if the sample passed the cellotape / crosscut peeling test, peeling of the copper vapor deposition layer was observed due to repeated bending.
Therefore, in the present invention, in order to determine the repeated flex resistance required for the flexible printed circuit substrate, a polyester adhesive tape having a stronger adhesive force than cellophane tape / cross-cut peeling test was conducted, and it was confirmed that there was no problem. (The residual rate of squares is almost 100/100).

The good adhesion of the vapor-deposited copper layer was also confirmed by the following heat seal peeling test. That is, a laminated film having an ionomer resin layer, which has been confirmed to have good thermal adhesiveness to a copper metal surface, as a heat-sealing layer (“Tough Top” manufactured by Toray Industries, Inc., thickness 120 μm)
m) was heat-sealed on the copper vapor-deposited layer surface of the sample under the conditions of a seal width of 5 mm, a seal temperature of 140 ° C. and a load of 1.5 kg for 1 second (FUJI MFG shop sealer (FS-
215 type) used). For this heat seal sample,
Toyo Baldwin tensile tester (UTM-
III-100), a T-type peeling test was performed on the non-sealed end under conditions of a chuck distance of 30 mm, a pulling speed of 200 mm / min, and a stroke of 100 mm, and the peeling force was measured. In the present invention, a peel strength of 5 g / mm (25 g / 5 mm width) or more is secured by this heat seal peel test. Further, within the scope of the present invention, the peeling interface when the peeling strength is relatively small is the primer layer / substrate, and when the peeling strength is larger, the peeling test is completed in the form of breaking the substrate film, In any case, sufficient adhesion strength between the copper vapor deposition layer / primer layer has been confirmed.

The copper vapor deposition base material of the present invention comprises a rust preventive agent layer containing a benzazole compound as a main component, formed on the above copper vapor deposition layer.

Conventionally, as a compound having an anticorrosive action on copper, in addition to a bicyclic benzazole compound, a monocyclic imidazole, an alkylimidazole, a triazole, a rosin or the like has been known. Of these, rosin has a good antirust effect, but impairs the suitability for application of the resist ink for etching for forming the electrode pattern. Further, imidazole, triazole and the like have a poor rust preventive effect. On the other hand, alkyl imidazole has a rust-preventing action higher than that of a benzazole compound, but since it forms a relatively thick rust-preventing layer, it deteriorates the electrical characteristics of the copper vapor-deposited layer and the coating suitability of a resist ink for etching is not good. .

The benzazole compound used in the present invention includes benzimidazole, mercaptobenzimidazole, benzotriazole, tolyltriazole, mercaptobenzothiazole and derivatives thereof. All of these have good rust-preventive action on the copper vapor-deposited layer and have little adverse effect on electrical properties, but among them, benzotriazole or / and its derivatives, especially water-soluble amines, show good action. Salt (eg,
Monoethanolamine salt and diethylamine salt) are preferably used. Among them, a mixture of benzotriazole and its water-soluble amine salt in a weight ratio of 1: 0.1 to 3 is preferable.

The above-mentioned benzoazole compound is soluble in water or alcohol and is applied as a solution of about 0.1 to 5% by weight on the copper vapor deposition layer. If necessary, a nonionic or amphoteric surfactant, a water-soluble plasticizer, or the like is added to the solution.

When applied to the copper vapor deposition layer, a method of immersing the substrate on which the copper vapor deposition layer is formed in the above solution and pulling up the copper vapor deposition substrate is preferably used, but spraying, gravure coater, brush coating, etc. A suitable rust preventive layer is also formed by the above method. The rust preventive layer thus formed is
It is an extremely thin layer of 50 to 1000 Å of the benzoazole compound, and exhibits an excellent anticorrosive action on the copper vapor-deposited layer, but it does not impair its electrical characteristics.

The copper vapor-deposited substrate of the present invention obtained as described above is then applied with a predetermined resist ink, etching with an aqueous solution of ferric chloride, soldering treatment, etc.
As a flexible printed circuit, an electronic desk calculator,
It is built into cameras, watches, video cameras, telephones, audio equipment, printer display equipment, etc.

[0028]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples, "part" and "%" are
All are based on weight.

Example 1 A 30% solution of saturated polyester resin (SP value = 9 to 10) (solvent: cyclohexanone / ethyl cellosolve / dioxane = 50/30/20, manufactured by Seiko Kasei Co., Ltd. "U"
Z164 ") 100 parts, 20 parts of methylolated melamine (the same" M80 ", solid content 80%) and hypophosphorous acid (50% solution further diluted 10 times with MEK)
5 parts were added, and these were mixed with cyclohexanone / ethyl cellosolve / dioxane (= 50/30/20) mixed solvent 10
It was dissolved in 0 part to obtain a polyester-based crosslinkable resin primer solution. Apply this primer solution to P with a thickness of approximately 38 μm.
120 on ET film (“Lumirror” manufactured by Toray Industries, Inc.)
Apply with a gravure coater of mesh, 150 in a heating machine
It was heated at 0 ° C. for 3 minutes to form a polyester-based crosslinked primer layer having a thickness of about 2 μm.

Then, the PET film treated as described above was placed in a vacuum vapor deposition machine (Bell jar test vapor deposition machine "EBV-6DH" manufactured by Nippon Vacuum Co., Ltd.), and an evaporation source (purity 9
99.99% Cu is added) is arranged at a distance of about 30 cm,
After the system was evacuated to 3 × 10 ⁻⁵ Torr, vapor deposition was performed to form a copper vapor deposition layer having a thickness of about 0.3 μm on the primer layer.

Then, on the surface of the copper vapor-deposited layer, a benzotriazole-based rust preventive (“Pal C” manufactured by Tatsuta Electric Wire Co., Ltd .: about 10% alcohol solution of about 2: 1 mixture of benzotriazole and its monoethanolamine salt). ), A 50-fold diluted solution of methanol was applied by a 200 mesh gravure coater and dried at 70 ° C. to form an anticorrosion layer having a thickness of about 100Å, to obtain a copper vapor deposition substrate of the present invention.

Comparative Example 1 A thickness of about 0.3 directly on the PET film used in Example 1.
A copper vapor deposition layer having a thickness of μm was formed to obtain a copper vapor deposition base material.

Comparative Example 2 A copper vapor-deposited base material was obtained in the same manner as in Example 1 except that the rust preventive layer was not formed.

Each of the copper vapor-deposited base materials obtained in Example 1 and Comparative Examples 1 and 2 was slit into a width of 15 mm and a length of 100 mm, and then unnecessary copper vapor-deposited film was removed with a ferric chloride solution. Ten strip-shaped samples each having a conductor width of 0.5 mm were obtained. When the resistance values in the length direction of these strip-shaped samples were measured, they showed an initial value (R ₀ ) of 5.1 to 5.5Ω. Next, these strip samples are treated at 60 ° C and 90%.
When the resistance value in the longitudinal direction (R _t ) was measured after the RH was left standing in a constant temperature and constant humidity test tank for a predetermined time, the results shown in Table 1 below were obtained.

[0035]

[Table 1]

According to the results of accelerated deterioration test in Table 1 above, the copper vapor-deposited base material of Example 1 showed sufficient durability as a substrate for flexible printed circuits, while Comparative Examples 1 and 2 showed remarkable resistance. Deterioration of the copper vapor deposition layer represented by the increase of the
It is noted that the copper vapor-deposited base material of No. 1 is severely deteriorated.

Example 2 A primer solution prepared by adding 1 part of methylolated melamine (“M80”) and 0.5 part of hypophosphorous acid (“p”) to 100 parts of a saturated polyester resin solution (“UZ164”) was added. Copper deposition was performed in the same manner as in Example 1 except that a crosslinked primer layer was formed using the above, and a copper vapor deposition substrate was obtained.

Comparative Example 3 A copper vapor-deposited substrate was obtained by performing copper vapor deposition in the same manner as in Example 1 except that the primer layer was formed using the primer solution from which methylolated melamine and hypophosphorous acid were removed.

In the copper vapor-deposited base materials of Example 2 and Comparative Example 3 and the copper vapor-deposited base material of Example 1 which had been subjected to copper vapor deposition and before the formation of the rust preventive layer, the polyester adhesive tape crosscut test described in the above text was carried out. A heat seal peel strength measurement test was performed. The results are shown in Table 2 below.

[0040]

[Table 2] * 1: 6 points average * 2: 6 points all broke in PET film layer * 3: 4 points average (remaining 2 points broke in PET film layer)

The results in Table 2 above show that when the amount of the crosslinkable component (methylolated melamine) is as small as about 3 parts based on 100 parts of the saturated polyester resin (Example 2), it is as high as 53 parts (Example 2). While a primer / copper vapor-deposited interlayer adhesion strength that is not so much discolored as that of Example 1) is obtained, in the copper vapor-deposited substrate lacking a crosslinking component and having an uncrosslinked polyester primer layer (Comparative Example 3). , Polyester adhesive tape cross-cut peeling test and peeling strength test show that sufficient primer / copper deposition interlayer adhesion strength is not obtained.

Example 3 Instead of the crosslinkable primer resin solution used in Example 1, a crosslinkable acrylic resin solution (Seiko Kasei Co., Ltd.) was used.
"UB267" manufactured by K.K., and the curing temperature was 180 ° C, and the acrylic cross-linked primer layer having a thickness of 2 µm was formed, to obtain a copper vapor-deposited base material of the present invention in the same manner as in Example 1.

Example 4 Instead of the crosslinkable primer resin solution used in Example 1, a crosslinkable polyurethane resin solution (polyurethane resin solution obtained by modifying polyester polyol with isophorone diisocyanate (solvent: methyl ethyl ketone, solid content 25%, Seiko Kasei Co., Ltd. “UZ60
2 ") to 100 parts, 20 parts of hexamethylene diisocyanate (the same" U-4000 ", solid content 75%) and 0.5 part of a tin-based catalyst (the same" UY-5 ") are added, and further to 150 parts of methyl ethyl ketone. (Dissolved)
A copper vapor-deposited base material of the present invention was obtained in the same manner as in Example 1 except that a polyurethane-based crosslinked primer layer having a thickness of 2 μm was formed.

With respect to the copper vapor-deposited base materials obtained in Examples 3 and 4, the results of the accelerated deterioration test conducted in the same manner as in Example 1 were carried out. The results of the tape crosscut peel test are shown in Table 3 below.

[0045]

[Table 3]

Example 5 The same primer solution as in Example 1 was applied onto a polyimide (PI) film (“apical” manufactured by Kaneka Kagaku Kogyo Co., Ltd.) having a thickness of about 25 μm with a 120-mesh gravure coater and heated. Heated at 150 ° C for 3 minutes in the machine to a thickness of about 2 μm
To form a polyester-based crosslinked primer layer.

Then, the PI film treated as described above was subjected to copper deposition in the same manner as in Example 1 to obtain a copper deposited substrate.

Comparative Example 4 A copper vapor deposition substrate was obtained by performing copper vapor deposition in the same manner as in Example 5 except that the primer layer was formed using the primer solution from which methylolated melamine and hypophosphorous acid were removed.

Example 6 The same primer solution as in Example 1 was applied onto an aromatic polyamide (PA) film (“Aramid film” manufactured by Toray Industries, Inc.) having a thickness of about 16 μm with a 120 mesh gravure coater and heated. It was heated in a machine at 150 ° C. for 3 minutes to form a polyester-based crosslinked primer layer having a thickness of about 2 μm.

Then, the PA film treated as described above was subjected to copper vapor deposition in the same manner as in Example 1 to obtain a copper vapor deposited substrate.

Comparative Example 5 A primer layer was formed on a PA film in the same manner as in Example 6 except that the primer solution from which methylolated melamine and hypophosphorous acid were removed was used, and then copper vapor deposition was performed. I got the material.

With respect to the copper vapor-deposited base materials of Examples 5 and 6 and the copper vapor-deposited base materials of Comparative Examples 4 and 5, the heat seal peeling strength measurement as described in the above text was performed. The results are shown in the table below.

[0053]

[Table 4]

[0054]

As described above, according to the present invention, a crosslinked resin primer is formed on a synthetic resin film substrate, and then a copper vapor deposition layer and a rust preventive agent layer composed of a benzazole compound are formed. Provided is a copper vapor-deposited base material having excellent durability, which is suitable as a substrate for a flexible printed circuit. This also eliminates the inconvenience of the flexible printed circuit board using the copper foil.

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Claims (4)

[Claims] 1. A film-form copper vapor deposition substrate comprising a synthetic resin film substrate, a cross-linking resin primer layer, a copper vapor deposition layer, and a rust preventive agent layer containing a benzazole compound as a main component, which are sequentially formed on the synthetic resin film substrate. . 2. The film-shaped copper vapor-deposited substrate according to claim 1, wherein the crosslinked resin primer layer is made of a polyester-based crosslinked resin. 3. The film-form copper vapor deposition substrate according to claim 1, wherein the peel strength between the primer layer and the copper vapor deposition layer measured by a heat seal peel test is 5 g / mm or more. 4. The film-form copper-deposited copper substrate according to claim 1, wherein the benzoazole compound comprises benzotriazole or / and a water-soluble amine salt thereof.