Re-peelable adhesive film, laminate and method for manufacturing circuit board

Abstract

To provide a re-peelable adhesive film which can exhibit high mass productivity and good productivity, when a circuit board is manufactured.SOLUTION: A re-peelable adhesive film has a re-peelable adhesive layer on a base material, wherein respective resin films of a plurality of laminated films having metal layers on the resin films are arranged side by side in a longitudinal direction on the same plane as the re-peelable adhesive film at intervals, and are bonded to the re-peelable adhesive layer in a peelable manner.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a removable adhesive film, a laminate, and a circuit board. [Background technology]

[0002] A laminate in which a resin film is used as a resin layer and a metal foil or the like is laminated thereon as a metal layer is used by processing the metal layer into a desired pattern depending on the application. Conventionally, circuit boards having processed metal patterns have been produced by, for example, attaching a substrate to the resin film side of a laminate having copper foil formed on the surface of a resin film via an adhesive, then coating the metal foil with a resist, exposing to light, developing, etching, peeling off the resist, and finally peeling off the substrate.

[0003] In the above-mentioned manufacturing method, since one laminate is usually applied to one base material, only one circuit board can be produced, and there is room for improvement in terms of mass productivity.

[0004] Therefore, Patent Document 1 proposes a method for manufacturing a tape carrier for mounting a semiconductor device, which includes an adhesion step of adhering two material tapes having a resin film and a copper layer fixed thereto using an adhesive layer, a lamination step of laminating a dry film as an etching resist onto the copper layer of the adhered material tapes, a resist pattern formation step of exposing and developing the dry film to form a resist pattern, a wiring pattern formation step of etching the copper layer using the resist pattern as a mask to form a wiring pattern, and then removing the resist pattern, and a peeling step of peeling the resin films from the adhesive layer to obtain two tape carriers for mounting a semiconductor device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-250694 A Summary of the Invention [Problem to be solved by the invention]

[0006] According to the manufacturing method described in Patent Document 1, two tape carriers for mounting semiconductor devices can be obtained, which can be said to be more mass-producible than conventional methods. However, if there are resin films above and below, it is difficult to peel them off at the same time. Therefore, one side is peeled off first, and then the other side is peeled off. However, when peeling off the other side, it is necessary to cover the exposed adhesive layer of one side, which makes the work complicated and there is a concern that good productivity cannot be achieved. Furthermore, only two sheets, a top and a bottom, can be produced, and the method of Patent Document 1 has limitations when considering increasing mass productivity.

[0007] In view of the above, the present invention has been made, and an object of the present invention is to provide a removable adhesive film that can achieve high mass productivity and good productivity when producing circuit boards. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by the present invention described below, and have completed the present invention.

[0009] [1] A removable adhesive film having a removable adhesive layer on a substrate, A removable adhesive film in which each of a plurality of laminated films having a metal layer on a resin film is releasably adhered to the removable adhesive layer, with the resin film being parallel to the longitudinal direction at intervals on the same surface of the removable adhesive film. [2] The removable adhesive film according to [1], wherein the peel strength between the removable adhesive layer and the resin film is 0.01 N / 25 mm or more. [3] Immerse the removable adhesive film in a ferric chloride solution with a Baume degree of 40° for 10 minutes at room temperature and measure the color difference (ΔE *ab) before and after immersion, the change in color difference is 4 or less. [4] The removable adhesive film according to any one of [1] to [3], wherein the substrate has a glass transition temperature of 30° C. or higher. [5] The removable adhesive film according to any one of [1] to [4], which has a width of 200 mm to 1500 mm. [6] A laminate comprising a removable adhesive film in any one of [1] to [5], The laminate comprises a plurality of laminate films each having a metal layer on a resin film, the resin films being spaced apart, parallel to each other in the longitudinal direction on the same surface of the removable adhesive film, and releasably bonded to the removable adhesive layer. [7] The laminate according to [6], wherein the interval is 3 mm to 100 mm. [8] A method for manufacturing a circuit board, comprising: a resist formation step of forming a resist layer on a metal layer of the laminate described in [6] or [7]; a development step of exposing and developing the resist layer; and an etching step of etching the metal layer after development to form a circuit pattern. [9] The method for producing a circuit board according to [8], wherein at least one of the resist forming step, the developing step, and the etching step is carried out by roll-to-roll. Effect of the Invention

[0010] According to the present invention, it is possible to provide a removable adhesive film that can exhibit high mass productivity and good productivity when producing a circuit board. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an explanatory diagram illustrating an example of a removable adhesive film according to the present embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of a laminate according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a method for producing a removable adhesive film, a laminate, and a circuit board according to one embodiment of the present invention (this embodiment) will be described.

[0013] [Removable adhesive film] As shown in FIG. 1, the removable adhesive film 10 of this embodiment is a removable adhesive film having a removable adhesive layer 14 on a substrate 12, and each resin film 22 of a plurality of laminated films 20 having a metal layer 24 on a resin film 22 is releasably adhered to the removable adhesive layer 14 with a gap between them and parallel to the longitudinal direction on the same surface of the removable adhesive film 10.

[0014] As described above, the removable adhesive film according to the present embodiment enables simultaneous development, etching, and other processes for multiple substrate materials in the manufacture of circuit boards, improving productivity and mass production, thereby reducing costs. In addition, since multiple resin films are provided on the same side, the workability in various steps in the manufacture of circuit boards is good, and good productivity can be achieved.

[0015] (base material) The glass transition temperature (TG) of the substrate according to the present embodiment is preferably 10° C. or higher, and more preferably 60 to 90° C. When the glass transition temperature is 10° C. or higher, a heated roll may be used for thermocompression bonding when laminating a resist film onto a metal foil, and the plastic used in the removable adhesive substrate can be prevented from being deformed by heat due to the heat generated during heating. The glass transition temperature can be measured using a product called "DSC7000X" manufactured by Hitachi High-Tech Science Corporation.

[0016] Examples of the substrate include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polycarbonate; polyolefins such as polyethylene and polypropylene; polystyrene; triacetyl cellulose; poly(meth)acrylate; polyvinyl chloride; polyether ether ketone; polyamide; polyimide; fluorine-based resins; etc. Among these resins, polyethylene terephthalate is preferred from the viewpoints of cost and TG. The substrate may be one which has been subjected to a corona treatment, plasma treatment or other treatment for improving adhesion, as required. Of these, corona treatment is preferred for practical use.

[0017] From the viewpoint of stably arranging a plurality of resin films, the thickness of the substrate is preferably 0.005 mm to 0.250 mm, and more preferably 0.020 mm to 0.100 mm.

[0018] The peel strength between the removable adhesive layer and the resin film is preferably 0.01 N / 25 mm or more, more preferably 0.03 to 10 N / 25 mm, and even more preferably 0.05 to 7 N / 25 mm. By having a peel strength of 0.01 N / 25 mm or more, the adhesion between the removable adhesive layer and the resin film is maintained in various steps when producing a circuit board, and thus handling can be improved. The peel force can be measured by the method described in the Examples.

[0019] (Removable adhesive layer) As the adhesive for forming the removable adhesive layer according to the present embodiment, from the viewpoint of obtaining good releasability with a peeling force of 0.01 N / 25 mm or more, (meth)acrylic, polyester, polyolefin, polyamide, urethane, polyether, rubber, silicone, etc. can be mentioned. Among them, from the viewpoint of heat resistance, durability, low cost, etc., it is preferable to contain a (meth)acrylic resin as a resin component ((meth)acrylic resin component). And, as the (meth)acrylic resin, a (meth)acrylic resin mainly composed of a (meth)acrylic acid ester can be suitably used. More specifically, an acrylic acid ester copolymer obtained by copolymerizing a (meth)acrylic acid ester with another monomer can be mentioned.

[0020] In this specification, the term "(meth)acrylic" includes both acrylic and methacrylic. In addition, the term "resin component" refers not only to the resin itself, but also to a portion of the reaction product derived from the resin when the resin reacts with other resins or monomers (polymerization, crosslinking, etc.). For example, in the case of a (meth)acrylic resin component, when a crosslinked product is formed with the (meth)acrylic resin itself and, for example, a crosslinking agent, the term also refers to a crosslinked portion.

[0021] Examples of the acrylic acid ester include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, hydroxyethyl acrylate, propylene glycol acrylate, acrylamide, and glycidyl acrylate. Among them, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferably used. The alkyl acrylate may be used alone or in combination.

[0022] Examples of other monomers include methyl acrylate, methyl methacrylate, styrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, propylene glycol acrylate, acrylamide, methacrylamide, glycidyl acrylate, and glycidyl methacrylate. Examples of the monomers include dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, and n-ethylhexyl methacrylate. Among them, n-ethylhexyl methacrylate is preferably used. These other monomers may be used alone or in combination.

[0023] The unit ratio (acrylic ester / other monomer) of the acrylic ester contained in the acrylic ester copolymer used as the acrylic adhesive in this embodiment to the other monomer is not particularly limited as long as the acrylic ester copolymer can exhibit the desired adhesive strength, and can be set appropriately depending on the application, etc.

[0024] The weight-average molecular weight (Mw) of the acrylic acid ester copolymer used as the acrylic adhesive in the present embodiment is not particularly limited as long as it exhibits the desired adhesive strength, but is preferably in the range of 200,000 to 2,500,000, and more preferably in the range of 600,000 to 2,200,000. The weight-average molecular weight can be determined as a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0025] The adhesive constituting the removable adhesive layer may contain, together with the (meth)acrylic resin, a crosslinking agent such as an epoxy crosslinking agent, an isocyanate crosslinking agent, an aziridine crosslinking agent, a metal chelate crosslinking agent, etc. Among these, the epoxy crosslinking agent and the isocyanate crosslinking agent are preferred.

[0026] As the epoxy crosslinking agent, for example, a polyfunctional epoxy compound can be used. Examples of such polyfunctional epoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polybutadiene diglycidyl ether, etc.

[0027] Examples of the isocyanate-based crosslinking agent include a polyisocyanate compound, a trimer of a polyisocyanate compound, a urethane prepolymer having an isocyanate group at its terminal obtained by reacting a polyisocyanate compound with a polyol compound, or a trimer of such a urethane prepolymer. The polyisocyanate compound is not particularly limited, and examples thereof include 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate.

[0028] Examples of the aziridine crosslinking agent include N,N'-toluene-2,4-bis(1-aziridinecarboxylate), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxylate), triethylenemelamine, bisisopropyl-1-(2-methylaziridine), and tri-1-aziridinylphosphine oxide.

[0029] The above-mentioned metal chelating crosslinking agent has a metal element and a salt-forming site, and when used together with the above-mentioned pressure-sensitive adhesive, the metal element can be crosslinked by forming a chelate bond with a carboxyl group or the like of the pressure-sensitive adhesive.

[0030] Examples of such metal chelating crosslinking agents include aluminum chelating compounds such as aluminum isopropylate, aluminum butyrate, aluminum ethylate, aluminum ethylacetoacetate, aluminum acetylacetonate, aluminum monoacetylacetonate bis(ethylacetoacetate), and aluminum alkylacetoacetate; dipropoxy-bis(acetylacetonato)titanium, dibutoxytitanium bis(octylene glycolate), dipropoxytitanium bis(ethylacetoacetate), dipropoxytitanium bis(lactate), dipropoxytitanium bis(triethanolamine), and di-n-butoxytitanium bis(triethanolamine). Examples of the organic carboxylic acid metal salts include zinc octoate, zinc laurate, zinc stearate, and tin octoate; and zinc chelate compounds such as acetylacetone zinc chelate, benzoylacetone zinc chelate, dibenzoylmethane zinc chelate, and ethyl acetoacetate zinc chelate.

[0031] The content of the crosslinking agent as described above varies depending on the type of the crosslinking agent, but is preferably within a range of 0.5 to 20 parts by mass, and more preferably within a range of 2.0 to 10.0 parts by mass, relative to 100 parts by mass of the adhesive as described above. By using 0.5 to 20 parts by mass, the adhesive layer can have good strength.

[0032] Here, in order to make the peel strength between the removable adhesive layer and the resin film 0.01 N / 25 mm or more, the thickness of the removable adhesive layer should be 3 μm or more.

[0033] A pressure-sensitive adhesive can also be used as the adhesive constituting the removable adhesive layer. The pressure-sensitive adhesive is an active energy (e.g., ultraviolet or electron beam) curable adhesive, which has sufficient adhesive strength before irradiation with active energy rays, but has a reduced adhesive strength after irradiation with active energy rays, allowing it to be easily peeled off from the adherend.

[0034] Specifically, the pressure-sensitive adhesive may be an adhesive such as a known active energy curing acrylic resin, silicone resin, epoxy resin, styrene-butadiene, SBS or SIS, isoprene, chloroprene, or acrylic butadiene elastomer polymer, or natural or regenerated rubber. In particular, an acrylic resin pressure-sensitive adhesive is preferred. If necessary, a tackifier such as polyterpene resin, gum rosin, rosin ester or rosin derivative, oil-soluble phenolic resin, coumarone-indene resin, or petroleum-based hydrocarbon resin may be blended. In addition, any type of pressure-sensitive adhesive such as a solvent type, emulsion type, or solventless type may be used.

[0035] The removable adhesive layer may contain other additives, such as an antioxidant, an ultraviolet absorbing agent, a photopolymerization initiator, and the like.

[0036] The thickness of the removable adhesive layer according to one embodiment of the present invention is preferably from 3 to 100 μm, and more preferably from 4 to 30 μm, from the viewpoints of processability and cost.

[0037] From the viewpoint of the etching resistance of the removable adhesive layer in the removable adhesive film, the change in color difference measured by the following color difference measurement is preferably 4 or less, more preferably 2 or less, and even more preferably 1 or less. When the change in color difference is 4 or less, good etching resistance is exhibited. <Color difference measurement (etching resistance)> The re-peelable adhesive film was immersed in an aqueous solution of ferric chloride with a Baume degree of 40° for 10 minutes at room temperature (23°C), and the color difference (ΔE * ab) is measured.

[0038] In order to provide the above-mentioned etching resistance, a rubber-based, silicone-based, or acrylic-based resin can be used as the adhesive constituting the removable adhesive layer, and from the viewpoint of cost and processability, an acrylic resin is preferably used. In particular, it is preferable to contain 30% by mass or more of 2-ethylhexyl polyacrylate. As for the functional group of the acrylic resin, one having a hydroxyl group or a carboxyl group can be used, and the acid value is 1 to 50 mgKOH / g, preferably 20 to 40 mgKOH / g, or the hydroxyl value is 1 to 50 mgKOH / g, preferably 20 to 40 mgKOH / g. In addition, from the viewpoint of processability, the molecular weight is about 100,000 to 1,000,000, preferably about 400,000 to 800,000.

[0039] The width of the removable adhesive film (more specifically, the width of the substrate) is preferably from 200 mm to 1500 mm, and more preferably from 500 mm to 1500 mm, from the viewpoint of stably arranging a plurality of resin films.

[0040] The removable adhesive film can be produced, for example, by applying an adhesive to a substrate by a known coating method such as gravure coating, die coating or bar coating, and then drying or the like to form an adhesive layer.

[0041] [Laminate] As shown in FIG. 2, the laminate of this embodiment is a laminate 30 including a removable adhesive film 10 having a removable adhesive layer 14 on the aforementioned substrate 12, and each resin film 22 of a plurality of laminate films 20 having a metal layer 24 on the resin film 22 is releasably adhered to the removable adhesive layer 12 at a distance W from the substrate 12 on the same side of the removable adhesive film 10, with the longitudinal directions of the resin films 22 aligned in parallel.

[0042] From the viewpoint of workability, the distance W is preferably 3 mm to 100 mm, and more preferably 5 mm to 20 mm.

[0043] (Laminated film) The resin film in the laminated film according to the present embodiment can be made of the same material as the substrate used in the removable adhesive film. From the viewpoint of cost, the thickness of the resin film is preferably 0.005 mm to 0.250 mm, and more preferably 0.010 mm to 0.100 mm.

[0044] The metal layer in the laminate film according to this embodiment is used after being processed into a desired metal pattern by etching.

[0045] The metal for forming the metal layer is preferably at least one selected from the group consisting of copper, stainless steel, brass, silver, iron, aluminum, nickel and titanium. Among these, from the viewpoint of versatility in each application, at least one selected from the group consisting of copper and stainless steel is more preferable.

[0046] From the viewpoint of reducing the amount of material used while ensuring the strength of the metal pattern, the thickness of the metal layer is preferably 0.05 μm to 100 μm, and more preferably 0.1 μm to 50 μm.

[0047] The laminated film can be produced, for example, by laminating a metal foil onto a resin film to form a metal layer, or by plating or vapor-depositing a metal material onto a resin film to form a metal layer.

[0048] The laminated film of this embodiment can be manufactured by arranging the resin films of multiple laminated films in parallel in the longitudinal direction, spaced apart, on the same side of the peelable adhesive film on the adhesive layer of the peelable adhesive film that has been prepared.

[0049] The laminate of this embodiment can be subjected to known processing, etc., as necessary, and used as an electrode, wiring, conductive layer, heat dissipation layer, etc.

[0050] [Circuit board manufacturing method] The method for producing a circuit board according to this embodiment includes a resist formation step of forming a resist layer on the metal layer of the laminate of the present invention described above, a development step of exposing and developing the resist layer, and an etching step of etching the metal layer after development to form a circuit pattern.

[0051] (Resist formation process) The etching resist used in the resist formation process may be, for example, a dry film (DF). Dry films have flexibility, whereas etching resists made of liquid resists are brittle, and therefore have the advantage that scratches and cracks are less likely to occur in the etching resist. Note that normal liquid resists may also be used.

[0052] (Developing process) In the development step, the resist is exposed by projection exposure using a projection exposure machine, and the dry film is developed to form a resist pattern. As the alkaline aqueous solution used for development, it is preferable to use an inorganic alkaline aqueous solution such as Na2CO3 or K2CO3. The alkaline aqueous solution may contain a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, etc. The temperature of the developer in the development step is preferably kept constant within the range of 18°C ​​to 40°C.

[0053] If desired, after the development step, the resist pattern obtained may be subjected to a heat treatment at 100° C. to 300° C. By carrying out this heat treatment, the chemical resistance and resolution of the resist pattern may be improved. For heating, a suitable heating furnace using hot air, infrared rays, far infrared rays, etc. may be used.

[0054] (Etching process) In the etching process, an etching solution is sprayed onto the resist pattern to etch the metal layer to form a circuit pattern. Examples of the etching method include acid etching and alkaline etching, and the etching is performed by a method suitable for the photosensitive resin laminate used. The etching solution can be, for example, an aqueous hydrochloric acid solution, an aqueous ferric chloride solution, or a mixture thereof. Among them, an aqueous ferric chloride solution is preferred. The etching solution can also be sprayed. After the etching step, it is preferable to appropriately remove the resist pattern.

[0055] From the viewpoint of productivity, at least one of the resist forming step, the developing step, and the etching step (preferably all three steps) is preferably carried out by roll-to-roll. EXAMPLES

[0056] The present invention will now be described in more detail with reference to the following examples, but the present invention is not limited to these.

[0057] [Example 1] A 0.038 mm thick polyester sheet (glass transition temperature: 78°C, product name Lumirror 38T, manufactured by Toray Industries, Inc.) was prepared as the substrate. A hardener (product name tetrad-c, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added to an adhesive (product name Coponyl N-4900, manufactured by Mitsubishi Chemical Co., Ltd.) on the substrate, and the mixture was applied with a die to a dry thickness of 5 μm, and aged at 45°C for 7 days to produce a removable adhesive film having a removable adhesive layer on the substrate.

[0058] Here, the adhesive, Coponyl N-4900, is an acrylic adhesive and has a carboxylic acid as a functional group. The curing agent, tetrad-c, corresponds to an epoxy-based crosslinking agent and is a tetrafunctional aliphatic glycidylamine-type epoxy resin having a molecular weight of 366.49. The mass ratio of the adhesive to the curing agent was 100:3.

[0059] Next, two 0.050 mm thick polyester sheets (product name: Lumirror 50T, manufactured by Toray Industries, Inc.) were prepared as resin films. A copper foil (product name: CF-T4X-SV, manufactured by Fukuda Metal Foil and Powder Co., Ltd.) having a thickness of 18 μm was dry laminated as a metal layer onto each of the resin films to produce a laminated film. Next, the resin films of the two laminated films were attached to the same side of the removable adhesive film with a gap (30 mm) between them, with the longitudinal directions of the resin films aligned in parallel, to obtain a laminate. The obtained laminate was subjected to the following measurements and evaluations, the results of which are shown in Table 1.

[0060] <Peeling strength between removable adhesive layer and resin film> The part of the laminate where the laminate film and the removable adhesive film were laminated was cut to a size of 25 mm x 300 mm to prepare a test piece. The peel strength was measured using a Shimadzu AGS-X tabletop precision universal testing machine, and the peel force was measured. The removable adhesive substrate was folded back, the peel angle was 180°, and the peel speed was 300 m / min.

[0061] <Etching resistance> A portion of the re-adhesive film where the laminated film was not provided (the gap W portion in FIG. 2) was cut out and used as a sample. This sample was immersed in an aqueous solution of ferric chloride with a Baume degree of 40° at room temperature (23° C.) for 10 minutes, and the color difference (ΔE * ab) were measured using a multi-light source spectrophotometric colorimeter, model MSC-P, manufactured by Suga Test Instruments Co., Ltd. The viewing angle of the C light source was 2°.

[0062] [Example 2] A removable adhesive film was produced in the same manner as in Example 1, except that a 0.040 mm thick polypropylene sheet (glass transition temperature: -3°C, product name Alphan PK002, manufactured by Oji F-Tex Co., Ltd.) was used as the substrate. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0063] [Example 3] A removable adhesive film was prepared in the same manner as in Example 1, except that the removable adhesive layer had a thickness of 1 μm. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0064] [Example 4] A removable adhesive film was prepared in the same manner as in Example 1, except that no curing agent was used in the preparation of the removable adhesive layer. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0065] [Example 5] A removable adhesive film was prepared in the same manner as in Example 1, except that a 0.040 mm thick polypropylene sheet (glass transition temperature: -3°C, product name Alphan PK002, manufactured by Oji F-Tex Co., Ltd.) was used as the substrate and the removable adhesive layer was 1 μm thick. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0066] [Example 6] A 0.040 mm thick polypropylene sheet (glass transition temperature: -3°C, product name Alphan PK002, manufactured by Oji F-Tex Co., Ltd.) was used as the substrate, the removable adhesive layer was 1 μm thick, and further, no curing agent was used in the removable adhesive layer. A removable adhesive film was produced in the same manner as in Example 1, except that the film was peelable. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0067] [Example 7] A removable adhesive film was prepared in the same manner as in Example 1, except that the removable adhesive layer had a thickness of 25 μm. A laminate was produced in the same manner as in Example 1, and the laminate was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0068] In addition, in all the examples, two laminated films for forming circuits are obtained from one laminate, which shows that the mass productivity is excellent. In addition, since the laminates obtained in each example can be subsequently subjected to a conventional circuit formation process, there is no need for special treatment as in Patent Document 1, and good productivity can be expected.

[0069] [Table 1] [Explanation of symbols]

[0070] 10. Removable adhesive film 12...Base material 14. Removable adhesive layer 20...Laminated film 22...Resin film 24...metal layer

Claims

1. A removable adhesive film having a removable adhesive layer on a substrate, A removable adhesive film in which each of a plurality of laminated films having a metal layer on a resin film is releasably adhered to the removable adhesive layer, with the resin film being parallel to the longitudinal direction at intervals on the same surface of the removable adhesive film.

2. 2. The removable adhesive film according to claim 1, wherein the peel strength between the removable adhesive layer and the resin film is 0.01 N / 25 mm or more.

3. The re-peelable adhesive film was immersed in an aqueous solution of ferric chloride with a Baume degree of 40° for 10 minutes at room temperature, and the color difference (ΔE * 2. The removable adhesive film according to claim 1, wherein the change in color difference between before and after immersion is 4 or less when the color difference between before and after immersion is measured.

4. 2. The removable adhesive film according to claim 1, wherein the substrate has a glass transition temperature of 30° C. or higher.

5. 2. The removable adhesive film according to claim 1, which has a width of 200 mm to 1500 mm.

6. A laminate comprising the removable adhesive film according to any one of claims 1 to 5, The laminate comprises a plurality of laminate films each having a metal layer on a resin film, the resin films being spaced apart, parallel to each other in the longitudinal direction on the same surface of the removable adhesive film, and releasably bonded to the removable adhesive layer.

7. The laminate according to claim 6, wherein the interval is from 3 mm to 100 mm.

8. 7. A method for manufacturing a circuit board, comprising: a resist forming step of forming a resist layer on the metal layer of the laminate according to claim 6; a developing step of exposing and developing the resist layer; and an etching step of etching the metal layer after the development to form a circuit pattern.

9. The method for producing a circuit board according to claim 8 , wherein at least one of the resist forming step, the developing step, and the etching step is performed by roll-to-roll.

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