Primer composition and laminate

Abstract

The objective is to provide a primer composition that forms a primer layer with excellent adhesion and bonding properties between a copper thin film layer and a transparent film, and which maintains excellent transparency even after etching. [Solution] The present invention provides a primer composition for forming the primer layer of a laminate in which a base layer, a primer layer, and a copper thin film layer are formed in this order, comprising a photocurable resin or a thermosetting resin, wherein the photocurable resin is an acrylate compound, and the thermosetting resin is a melamine resin and a polyol.

Description

Technical Field

[0001] The present invention relates to a primer composition and a laminate.

[0002] In recent years, with the high-performance improvement (miniaturization, weight reduction, thinning, etc.) of display technologies related to electronic devices, there has been a strong demand for high-performance improvement of electronic circuits and integrated circuits used. As a wiring substrate material for these electronic circuits and integrated circuits, a polyimide resin film having good heat resistance and insulation properties and excellent transparency has attracted attention. The process of metallizing the surface by forming a metal layer on this transparent polyimide resin film and forming a circuit has become one of the elemental technologies in the field of electronics.

[0003] For example, in Prior Art Document 1, a polyimide resin film is a polyimide film obtained by imidizing a polyamic acid obtained by reacting an aromatic diamine and an aromatic dianhydride, and the film has an inflection point of storage modulus in the range of 270°C to 340°C, and the peak top of tanδ, which is the value obtained by dividing the loss modulus by the storage modulus, is in the range of 320°C to 410°C, and the storage modulus at 400°C is 0.5 GPa to 1.5 GPa, and the storage modulus α1 (GPa) at the inflection point and the storage modulus α2 (GPa) at 400°C are within a specific range. According to this technology, it is possible to obtain a polyimide film with suppressed relaxation and uneven elongation, and a flexible metal-clad laminate with suppressed occurrence of defects during metal layer formation is realized.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional technologies have proposed laminates in which thin metal layers of nickel, chromium, titanium, etc. are formed on a transparent resin film such as polyimide, and an electrolytic copper layer is further attached thereon. However, problems have arisen due to the fact that the thin metal layers and the electrolytic copper layer are dissimilar metals. Specifically, it is difficult to select the optimal etching solution for each metal layer so as not to lose transparency during etching, and the adhesion between the layers is weak and they are easily peeled off, making it difficult to subdivide the circuits to be formed. One possible solution to these problems is to use copper for the thin metal layer and use the same type of metal, but this has not been realized due to the problem of poor adhesion between the transparent film and the copper thin metal layer.

[0006] Therefore, the main objective of the present invention is to provide a primer composition that can form a primer layer that exhibits excellent adhesion and bonding properties between a copper thin film layer and a transparent film, and that maintains excellent transparency even after etching. [Means for solving the problem]

[0007] The present inventors have found that a primer composition having a specific configuration, specifically a primer composition containing a photocurable resin that is an acrylate compound, or a thermosetting resin that is a melamine resin, can form a primer layer that exhibits excellent adhesion and bonding between a transparent film and a copper thin film layer, and maintains excellent transparency even after etching.

[0008] In other words, the present invention is A primer composition for forming the primer layer of a laminate in which a base layer, a primer layer, and a copper thin film layer are formed in this order, Containing a photocurable resin or a thermosetting resin, The aforementioned photocurable resin is an acrylate compound, The thermosetting resin is a melamine resin and a polyol. This invention provides a primer composition. In the primer composition containing the thermosetting resin, the polyol may be an alkyd polyol. In the primer composition containing the photocurable resin, the acrylate compound may be one or more selected from acrylic resin acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and urethane acrylate having 9 or more functional groups. Furthermore, the primer composition may satisfy the following requirements. Requirements: When a test specimen is prepared by applying the primer composition to a polyimide film, curing it, and then forming a copper thin film layer on the resulting primer layer by copper sputtering, and a cross-cut test is performed in accordance with JIS K5600-5-6, no delamination of the primer layer and the copper thin film layer from the substrate layer is observed, or the ratio of the area of ​​the primer layer and the copper thin film layer delaminated from the polyimide film to the total area of ​​the test specimen is 5% or less. In the aforementioned primer composition, the total light transmittance of the primer layer formed from the primer composition may be 86% or more, and the haze value may be 1.0% or less. In the aforementioned primer composition, the total light transmittance of the primer layer formed from the primer composition after etching is 86% or more, and the haze value after etching may be 1.0% or less. Furthermore, the present invention provides a laminate comprising a primer layer formed from the primer composition, a copper thin film layer, and a substrate layer, wherein the copper thin film layer and the substrate layer are bonded together by the primer layer. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a primer composition that can form a primer layer that exhibits excellent adhesion and bonding properties between a copper thin film layer and a transparent film, and that maintains excellent transparency even after etching. Furthermore, the effects of the present invention are not necessarily limited to those described herein, but may be any of the effects described herein. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments for implementing the present invention will be described in detail. Note that the embodiments described below show typical embodiments of the present technology, and the scope of the present technology is not limited only to these embodiments. In addition, in this specification, "X to Y" indicating a range includes the numerical values X and Y before and after it, and means "X or more and Y or less". In addition, the upper limit value (hereinafter) and the lower limit value (above) of each numerical range (~) can be arbitrarily combined as desired.

[0011] The present technology will be described in the following order. 1. First Embodiment (Example of Primer Composition Containing Photo-Curable Resin) (1) Configuration of Primer Composition (2) Explanation of Each Component (3) Physical Properties (4) Manufacturing Method of Primer Composition (5) Use of Primer Composition 2. Second Embodiment (Example of Primer Composition Containing Thermo-Curable Resin) (1) Configuration of Primer Composition (2) Explanation of Each Component (3) Physical Properties (4) Manufacturing Method of Primer Composition (5) Use of Primer Composition 3. Third Embodiment (Example of Laminate) (1) Configuration of Laminate (2) Explanation of Each Layer (3) Physical Properties (4) Manufacturing Method of Laminate (5) Use of Laminate 4. Examples

[0012] 1. First Embodiment (Example of Primer Composition Containing Photo-Curable Resin)

[0013] (1) Configuration of Primer Composition The primer composition according to the first embodiment of the present invention is a primer composition for forming the primer layer of a laminate in which a base material layer, a primer layer, and a copper thin film layer are formed in this order, and contains an acrylate compound as a photocurable resin. Further, the primer composition according to the present embodiment may further contain a photopolymerization initiator, a solvent, and other components described below as necessary.

[0014] (2) Explanation of each component [Photocurable resin] In this technology, a photocurable resin is a resin in which a crosslinked structure is formed by a reaction between an oligomer or monomer having polymerizability using radicals or cations generated by irradiation with ultraviolet rays or electron beams as starting species. Examples of the photocurable resin include compounds having a vinyl group, an acryloyl group, or an epoxy group. The photocurable resin according to the present embodiment is an acrylate compound having an acryloyl group from the viewpoint of forming a tough cured film layer (hereinafter also referred to as a primer layer) whose surface is not roughened even when copper sputtering treatment is performed. The acrylate compound is a resin in which the acrylate compounds crosslink and cure only at the ends, and a primer layer having excellent toughness can be stably obtained as compared with a two-component reaction type curable resin. And in this technology, by using an acrylate compound as the photocurable resin, a primer composition can be obtained that forms a primer layer excellent in adhesion and close adhesion between the copper thin film layer and the transparent film and also excellent in transparency even after etching treatment.

[0015] Examples of the acrylate compound according to the present technology include acrylate oligomers such as urethane acrylate, epoxy acrylate, acrylic resin acrylate, and polyester acrylate; acrylate monomers such as polyfunctional acrylate monomers and monofunctional acrylate monomers.

[0016] The acrylate oligomer can be any compound having one or more acryloyl groups in multiple repeating units, and can be selected from various known acrylate oligomers. Among the above acrylate oligomers, it is particularly preferable to select one or more from polyfunctional urethane acrylates with 9 or more functional groups or acrylic resin acrylates, from the viewpoint of adhesion, bonding, and transparency after etching between the copper thin film layer and the transparent film.

[0017] The polyfunctional urethane acrylate with 9 or more functional groups used in this technology is not particularly limited, and commercially available products can be used as appropriate. Examples include "UN-901T" (9 functional groups), "UN-952" (10 functional groups), "UN-904" (10 functional groups), "UN-905" (15 functional groups), and "UN-3320HS" (15 functional groups) sold by Negami Kogyo Co., Ltd., and "UV-7610B" (9 functional groups), "UV-7620EA" (9 functional groups), and "UV-1700B" (10 functional groups) sold by Mitsubishi Chemical Corporation.

[0018] The acrylic resin acrylate used in this technology is not particularly limited, and commercially available products can be used as appropriate. Examples include "ART CURE" sold by Negami Kogyo Co., Ltd. and "IRR679" sold by Daicel Ornex Co., Ltd.

[0019] The acrylate monomer can be any compound having one or more acryloyl groups, and can be selected from a variety of known acrylate monomers. Examples of acrylate monomers used in this technology include pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tripentaerythritol acrylate, diglycerin EO-modified acrylate (where EO means ethylene oxide), trimethylolpropane triacrylate, trimethylolpropane PO-modified triacrylate (where PO means propylene oxide), trimethylolpropane EO-modified triacrylate, alkoxylated pentaerythritol tetraacrylate, isopropyl alcohol Examples include anuric acid EO-modified diacrylate, isocyanuric acid EO-modified triacrylate, phenol EO-modified acrylate, 2-ethylhexyl EO-modified acrylate, N-acryloyloxyethyl hexahydrophthalimide, bisphenol FEO-modified diacrylate, bisphenol AEO-modified diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate, tris[2-hydroxyethyl]isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glyceryl triacrylate, and ditrimethylolpropane tetraacrylate. Among the above acrylate monomers, it is particularly preferable to use one or more selected from pentaerythritol triacrylate and pentaerythritol tetraacrylate from the viewpoints of adhesion, bonding, transparency after etching, curing speed, and toughness of the cured product between the copper thin film layer and the transparent film.

[0020] While there are no particular limitations on the content of the photocurable resin in this technology, it is preferable that the content be adjusted so that the thickness of the cured primer layer is 1 μm or less, from the viewpoint of forming a primer layer that has excellent adhesion and bonding properties between the copper thin film layer and the transparent film, and that remains highly transparent even after etching.

[0021] [Photopolymerization initiator] The primer composition according to this embodiment may further contain a photopolymerization initiator. The photopolymerization initiator mainly absorbs light energy in the ultraviolet region with a wavelength of 250 to 400 nm to generate radicals, which attack the double bonds of the acrylate compound, which is the photocurable resin, thereby initiating polymerization. The type and amount of the photopolymerization initiator can be broadly those commonly used in the photopolymerization of photopolymerizable acrylic polymers.

[0022] Examples of photopolymerization initiators used in this technology include alkylphenone-based photopolymerization initiators such as 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl-phenyl ketone, 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one, 1-[4-(2-hydroxyethoxyl)-phenyl]-2-hydroxy-methylpropanone, 2-benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; and acetophenones such as 2,2-dimethoxy-2-phenylacetophenone. Acyl phosphine oxide photopolymerization initiators such as bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)-phenylphosphineate, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; and benzophenone-based photopolymerization initiators such as benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, o-methylbenzoylbenzoate, 4-(4-methylphenylthio)benzophenone, 2-4-6-trimethylbenzophenone, 2,4-dimethylthioxanthone, 2-isopropylthioxanthone, and methylbenzoyl formate 4,4-bis(diethylamino)benzophenone can be used.

[0023] When the primer composition according to this embodiment contains a photopolymerization initiator, the amount of the photopolymerization initiator is not particularly limited, but from the viewpoint of forming a primer layer that has excellent adhesion and bonding properties between the copper thin film layer and the transparent film, and that remains transparent even after etching, it is preferable that the thickness of the cured primer layer be adjusted to 1 μm or less.

[0024] [solvent] The primer composition according to this embodiment may further contain a solvent as needed. The solvent functions as a diluent or viscosity modifier in the primer composition. By including the solvent, the reaction rate of the acrylate composition and the physical properties of the resulting cured product can be adjusted, as well as the viscosity when applying the primer composition. Any solvent can be used in this technology as long as it is compatible with the acrylate composition and does not inhibit the photocuring reaction.

[0025] Examples of solvents used in this technology include alcoholic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, isobutyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic solvents such as toluene, xylene, ethylbenzene, and mesitylene; and halogenated hydrocarbon solvents such as chloroform, carbon tetrachloride, dichloromethane, and trichloroethylene. One or more of these can be used in combination as needed.

[0026] When the primer composition according to this embodiment contains a solvent, the amount of the solvent is not particularly limited, but it is preferable that the amount is adjusted so that the thickness of the cured primer layer is 1 μm or less, from the viewpoint of forming a primer layer that has excellent adhesion and bonding properties between the copper thin film layer and the transparent film, and that remains transparent even after etching. The amount of the solvent can be appropriately selected by adjusting the reaction rate of the acrylate composition and the physical properties of the resulting cured product, as well as adjusting the viscosity when applying the primer composition. As for the amount of the solvent, for example, it can be adjusted so that the amount of the resulting cured product (solid component) relative to the primer composition is about 30% to 40% by mass.

[0027] [Other ingredients] The primer composition according to this embodiment may optionally contain other components. Examples of other components include colorants, photoinitiators, catalysts, adhesion promoters, chain transfer agents, polymerization inhibitors, antioxidants, rust inhibitors, thickeners, tackifiers, plasticizers, surfactants, defoamers, leveling agents, and other materials commonly used in the art.

[0028] (3) Physical properties [Transparency] The primer layer formed from the primer composition according to this technology has excellent transparency and can maintain excellent transparency even after etching. The transparency of the primer layer is evaluated by the total light transmittance and haze value described below. Excellent transparency is achieved if the total light transmittance and haze value are within the following ranges.

[0029] <Total light transmittance> The total light transmittance of the primer layer formed from the primer composition according to this technology is preferably 86% or higher, more preferably 87% or higher, and even more preferably 88% or higher. In this technology, the total light transmittance is obtained by the following measurement method.

[0030] (Preparation of test specimens with cured primer composition) First, the primer composition is filtered using a polytetrafluoroethylene membrane filter with a pore size of 0.5 μm (25JP050AN, manufactured by ADVANTEC). The filtered primer composition is then coated using a bar coater (wire bar No. #6, wire diameter 0.15 mm, mesh 167 strands / IN width, coating amount 6-7.5 WET gm). 2 Using a product manufactured by Marukyo Giken Co., Ltd., the primer is applied to a substrate layer to a dry film thickness of 1 μm or less. A polyimide film (CTFA25, manufactured by CEN ELECTRICAL MATERIAL Co., Ltd.) is used as the substrate layer. The substrate layer coated with this primer composition solution is cured by ultraviolet irradiation to obtain a test specimen in which the primer composition has been cured.

[0031] (Preparation of test specimens of laminates treated with copper sputtering) The test specimens obtained by the above method are subjected to copper sputtering using a sputtering apparatus (CFS-4ES, manufactured by Shibaura Mechatronics Co., Ltd.) to form a copper thin film layer with a film thickness of 50 nm.

[0032] (Preparation of test specimens of etched laminates) A test specimen of a copper sputtered laminate is etched using an etching solution (H-1000A, manufactured by Sunhayato Co., Ltd.) at 40°C for 10 minutes to obtain a test specimen for evaluating transparency after etching.

[0033] The obtained test specimens were measured for total light transmittance using a single-beam photometer (COH7700, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7361-1:1997.

[0034] <Haze value> The haze value of the primer layer formed from the primer composition according to this technology is preferably 1.0% or less, more preferably 0.9% or less, and even more preferably 0.8% or less. In this technology, the haze value is measured using a single-beam photometer (COH7700, manufactured by Nippon Denshoku Industries Co., Ltd.) on the test specimen used in the measurement of total light transmittance described above, in accordance with JIS K 7136.

[0035] The transparency of the primer layer formed from the primer composition relating to this technology is evaluated based on the total light transmittance and haze value according to the following criteria. Transparency is evaluated on test specimens of the primer composition relating to this technology that have been cured and test specimens of the laminate that have been etched.

[0036] <Evaluation Criteria> A: Total light transmittance of 86% or higher, and haze value of 1.0% or lower. C: Total light transmittance is 86% or higher, but the haze value exceeds 1.0%. or The haze value is 1.0% or less, but the total light transmittance is below 86%. D: Total light transmittance is below 86%, and the haze value is above 1.0%.

[0037] [Adhesion to polyimide film (primer layer, primer layer and copper thin film layer)] The primer composition according to this technology exhibits excellent adhesion and bonding between the primer layer, which is a cured layer of the copper thin film forming primer, and a transparent film (polyimide film). Even when a copper thin film layer is further formed on the primer layer, this excellent adhesion and bonding can be maintained. The adhesion to the polyimide film is evaluated by the cross-cut test described below. When the following cross-cut test is performed, if no delamination is observed from the substrate layer for the primer layer, the primer layer, and the copper thin film layer, or if the ratio of the area of ​​the delaminate layer to the total area of ​​the test piece is 5% or less, then the adhesion is excellent. Furthermore, the adhesion between the primer layer and the polyimide film will be evaluated on a test specimen in which the primer composition has cured, and the adhesion between the primer layer and the copper thin film layer and the polyimide film will be evaluated on a test specimen of the laminate subjected to the copper sputtering treatment described above.

[0038] <Cross-cut test> In accordance with JIS K 5600-5-6, cross-cuts were made on the cured primer composition specimens, which were prepared by measuring total light transmittance, using a cutting tool. The cut portions were inspected, and the adhesion was classified according to the following criteria.

[0039] Classification 0: The cut edges were perfectly smooth, and there was no peeling at any of the grid lines. Adhesion to the polyimide film was excellent. Classification 1: Small peeling of the coating at the intersection of cuts. The percentage of areas affected at the cross-cut sections does not clearly exceed 5%. Adhesion to the polyimide film was good. Classification 2: The coating peels along the edges of the cuts and / or at intersections. The affected area in the cross-cut portion is clearly more than 5%, but never exceeds 15%. Adhesion to the polyimide film was slightly poor. Classification 3: The coating is partially or completely peeling along the edges of the cuts, and / or peeling in various parts of the pattern, partially or completely. The affected area in the cross-cut section is clearly more than 15% but never exceeds 35%. Adhesion to the polyimide film was poor. Classification 4: The coating is partially or completely peeling along the edges of the cuts, and / or partially or completely peeling in several places. The affected area in the cross-cut section does not clearly exceed 35%. Adhesion to the polyimide film was poor. Classification 5: Any degree of peeling that cannot be classified under Classification 1. Poor adhesion to the polyimide film.

[0040] The adhesion of the cured primer composition related to this technology to the polyimide film (primer layer, primer layer, and copper thin film layer) is evaluated according to the following criteria based on the above classification. The adhesion to the polyimide film is evaluated on test specimens of the cured primer composition related to this technology and test specimens of the laminate that has been subjected to copper sputtering.

[0041] <Evaluation Criteria> S: Classification 0 (Excellent adhesion to polyimide film) A: Classification 1 (Good adhesion to polyimide film) B: Classification 2 (Slightly inferior adhesion to polyimide film) C: Classification 3 (Poor adhesion to polyimide film) D: Classification 4, 5 (Very poor adhesion to polyimide film)

[0042] [exterior] The appearance of the copper thin film layer on the test specimens cured with the above primer composition and the test specimens of the laminate subjected to copper sputtering is visually evaluated according to the following criteria.

[0043] <Evaluation Criteria> A: Good exterior condition C: Abnormalities detected (bulges, swelling, popping, etc.)

[0044] (4) Method for producing a primer composition The method for producing the primer composition of this embodiment is not particularly limited. The components may be mixed as they are, mixed after being dissolved or dispersed in a solvent, or a composition may be prepared in which some of the components are dissolved or dispersed in a solvent, and the remaining components may be mixed into this composition. Furthermore, the method for producing the primer composition may include a step of filtering the composition. The filtering can be carried out by conventionally known methods, for example, by using a membrane filter.

[0045] (5) Use of primer composition A method for forming a copper thin film layer and an electrolytic copper layer on a substrate layer such as a polyimide film using the primer composition of this embodiment will be described below. As a method for forming a copper thin film layer and an electrolytic copper layer on a polyimide film substrate layer using the primer composition of this embodiment, sputtering or electrolytic copper plating methods may be employed, respectively. The sputtering method and the electrolytic copper plating method include, for example, a first step of forming a primer layer by applying the primer composition to the surface of the polyimide film substrate layer and curing it by ultraviolet irradiation; a second step of forming a copper thin film layer by performing copper sputtering on the primer layer formed in the first step; and a third step of forming an electrolytic copper layer by performing electrolytic copper plating on the copper thin film layer formed in the second step. This makes it possible to form an electrolytic copper layer on the surface of the polyimide film substrate layer that has excellent adhesion and bonding properties, and also has excellent transparency even after etching.

[0046] In the first step, the primer composition can be applied by conventionally known methods, such as spraying, spin coating, dip coating, and roll coating, but is not limited to these methods.

[0047] In the first step, ultraviolet irradiation can be carried out by conventionally known methods, such as high-pressure mercury lamps or LED lamps. This results in a primer layer in which the primer composition has been cured.

[0048] In the second step, the metal sputtering method is used to perform copper sputtering on the primer layer formed in the first step. This second step allows for the formation of a copper thin film layer on the primer layer obtained in the first step.

[0049] In the second step, copper sputtering can be performed by conventionally known methods, such as vacuum deposition, but is not limited to this method.

[0050] In the third step, the electrolytic copper plating method involves performing electrolytic plating with electroplated copper on the copper thin film layer formed in the second step. The third step allows for the coating (deposition) of electroplated copper onto the copper thin film layer obtained in the second step, thereby forming an electroplated copper layer.

[0051] In the third step, the plating metal to be electroplated is not particularly limited, and examples include Ni, Co, Pd, Cu, Ag, Au, Pt, Sn, etc. However, in this technology, from the viewpoint of using the same type of metal, it is preferable to use Cu, and it is even more preferable to use electroplated copper. The electroplating solution (bath) to be used can be appropriately selected according to the type of metal, and for example, a known copper plating bath can be used.

[0052] 2. Second Embodiment (Example of a Primer Composition Containing a Thermosetting Resin)

[0053] (1) Composition of the primer composition The primer composition according to the second embodiment of the present invention is a primer composition for forming the primer layer of a laminate in which a substrate layer, a primer layer, and a copper thin film layer are formed in that order, and contains a melamine resin and a polyol as thermosetting resins. Furthermore, the primer composition according to this embodiment may further contain a solvent, a catalyst, and other components.

[0054] (2) Explanation of each component [Thermosetting resin] In this technology, the thermosetting resin is a resin that solidifies when heat is applied. Examples of thermosetting resins include phenolic resins, epoxy resins, melamine resins, urethane resins, modified polyester resins, cyanate resins, silicone resins, polyamide resins, and urea resins. In this embodiment, the thermosetting resins are melamine resin and polyol, from the viewpoint of transparency after copper sputtering, toughness of the coating film after thermosetting, and progress of the crosslinking reaction. By using melamine resin and polyol as thermosetting resins, a primer composition can be obtained that forms a primer layer with excellent adhesion and bonding between the copper thin film layer and the transparent film, and which also maintains excellent transparency after etching.

[0055] [Polyol] The polyol is not particularly limited as long as it is a compound having two or more hydroxyl groups (-OH) in one molecule, but examples include polyether polyols, polyester polyols, polymer polyols, acrylic polyols, and alkyd polyols. In this embodiment, the polyol is preferably an alkyd polyol and / or a polyether polyol, and more preferably an alkyd polyol, from the viewpoint of having a number of functional groups and a high hydroxyl value. Because the polyol contains many hydroxyl groups in its molecule, it reacts well with the melamine resin, resulting in a faster curing speed, greater toughness of the resulting cured product, and superior adhesion and bonding to the transparent film.

[0056] The hydroxyl value of the polyol is not particularly limited, but is preferably 100 to 400 mg KOH / g, more preferably 140 to 350 mg KOH / g, and even more preferably 180 to 330 mg KOH / g. When the hydroxyl value of the polyol is within the above range, the crosslinking density with the thermosetting resin is improved, the resulting cured product has excellent toughness, and the primer composition has an appropriate viscosity and excellent handling properties.

[0057] The content of the thermosetting resin in this technology is not particularly limited, but it is preferable that the thickness of the cured primer layer be adjusted to 1 μm or less, from the viewpoint of forming a primer layer that has excellent adhesion and bonding properties between the copper thin film layer and the transparent film, and that remains transparent even after etching.

[0058] [solvent] The description of the solvent in the first embodiment applies directly, so it will be omitted here.

[0059] [catalyst] The primer composition according to this embodiment may further contain a catalyst. The catalyst is not particularly limited as long as it accelerates the reaction of the thermosetting resin, and a wide range of catalysts commonly used in the reaction of thermosetting resins can be used.

[0060] When the primer composition according to this embodiment contains a catalyst, the amount of the catalyst is not particularly limited, but from the viewpoint of forming a primer layer that has excellent adhesion and bonding properties between the copper thin film layer and the transparent film, and that remains transparent even after etching, it is preferable that the amount of the cured primer layer be adjusted so that the thickness of the primer layer is 1 μm or less.

[0061] [Other ingredients] The description of the other components in the first embodiment applies directly, so it will be omitted here.

[0062] (3) Physical properties Regarding the physical properties of the primer composition according to the second embodiment, the description of the physical properties of the primer composition according to the first embodiment applies directly, except for the method of preparing the test specimens, so the description will be omitted. The method of preparing the test specimens will be described below.

[0063] (Preparation of test specimens with cured primer composition) First, the primer composition is filtered using a polytetrafluoroethylene membrane filter with a pore size of 0.5 μm (25JP050AN, manufactured by ADVANTEC). The filtered primer composition is then coated using a bar coater (wire bar No. #6, wire diameter 0.15 mm, mesh 167 strands / IN width, coating amount 6-7.5 WET gm). 2 Using a product manufactured by Marukyo Giken Co., Ltd., the primer is applied to the substrate layer to a dry film thickness of 1 μm or less. A polyimide film (CTFA25, manufactured by CEN ELECTRICAL MATERIAL Co., Ltd.) is used as the substrate layer. The substrate layer coated with this primer composition solution is heated in a heating furnace at a temperature of 120°C or 150°C and a heating time of 2 minutes or 10 minutes to cure it and obtain a test specimen in which the primer composition has been cured.

[0064] (Preparation of test specimens of laminates treated with copper sputtering) The test specimens obtained by the above method were subjected to copper sputtering using a sputtering apparatus (CFS-4ES, manufactured by Shibaura Mechatronics Co., Ltd.) to form a copper thin film layer with a film thickness of 50 nm.

[0065] (4) Method for producing a primer composition The method for producing the primer composition according to this embodiment is the same as the description in the relevant section of the first embodiment, so it will be omitted here.

[0066] (5) Use of primer composition Regarding the use of the primer composition according to the second embodiment, the description of the use of the primer composition according to the first embodiment applies directly, except for the description of the first step, so the description will be omitted. The first step according to this embodiment will be described below.

[0067] The first step in this embodiment is to apply the primer composition to the surface of the polyimide film substrate layer and heat-treat it to form a primer layer. In the first step, the heat treatment can be carried out by a conventionally known method, such as heating in a drying oven. This results in a primer layer in which the primer composition has been cured.

[0068] In the aforementioned heat treatment, the heating conditions are, for example, 80°C to 180°C for 1 to 60 minutes.

[0069] 3. Third Embodiment (Example of a Laminate)

[0070] (1) Structure of the laminate A laminate according to a third embodiment of the present invention is a laminate comprising a primer layer formed from the primer composition, a copper thin film layer, and a substrate layer, wherein the copper thin film layer and the substrate layer are bonded together by the primer layer. In the laminate, an electrolytic copper layer may be further included on the copper thin film layer.

[0071] (2) Explanation of each layer [Base material layer] The substrate layer in this embodiment is not particularly limited as long as it is a transparent resin film, and examples include polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, triacetylcellulose (TAC) film, cycloolefin polymer (COP) film, cyclic olefin copolymer (COC) film, polycarbonate (PC) film, acrylic resin film, and polyimide film. Among these, polyimide film is preferred as the substrate layer in this technology.

[0072] The thickness of the substrate layer can be appropriately selected depending on the application of the laminate of the present invention, but from the viewpoint of adhesion and bonding with the copper thin film layer via the primer layer, a range of 10 μm to 200 μm is preferred, a range of 20 μm to 100 μm is more preferred, and a range of 25 μm to 75 μm is even more preferred.

[0073] [Primer layer] In this embodiment, the primer layer is formed by coating the substrate layer with the primer composition. The primer layer provides excellent adhesion and bonding between the copper thin film layer and the transparent film, and also provides a laminate with excellent transparency even after etching.

[0074] The method for applying the primer composition is not particularly limited, but may include, for example, the gravure roll method, the reverse roll method, the offset gravure method, the kiss coat method, the reverse kiss coat method, the wire bar coat method, the spray coat method, the impregnation method, and the like.

[0075] The thickness of the primer layer can be appropriately selected depending on the application of the laminate of the present invention, but from the viewpoint of adhesion and bonding with the copper thin film layer via the primer layer, a range of 10 nm to 1000 nm is preferred, a range of 50 nm to 800 nm is more preferred, and a range of 100 nm to 700 nm is even more preferred.

[0076] [Copper thin film layer] In this embodiment, the copper thin film layer is formed by performing copper sputtering on the primer layer. Because the copper thin film layer allows the metal thin film layer in contact with the electrolytic copper layer to be made of the same metal, it solves the problems that arise when dissimilar metals are used for the metal thin film layer.

[0077] Copper sputtering is a process in which an inert gas is introduced under vacuum conditions, negative ions are applied to the copper to generate a glow discharge, the inert gas atoms are then ionized, and the gas ions are violently struck against the copper surface at high speed, ejecting copper atoms and molecules, which are then deposited onto the surface of the primer layer to form a thin copper film. For example, a sputtering apparatus (CFS-4ES, manufactured by Shibaura Mechatronics Co., Ltd.) can be used for this copper sputtering process.

[0078] The thickness of the copper thin film layer can be appropriately selected depending on the application of the laminate of the present invention, but from the viewpoint of adhesion and bonding with the substrate layer and the electrolytic copper layer via the primer layer, a range of 10 nm to 100 nm is preferred, a range of 20 nm to 80 nm is more preferred, and a range of 30 nm to 70 nm is even more preferred.

[0079] [Electrolytic copper layer] In the laminate according to this embodiment, an electrolytic copper layer may be further included on the copper thin film layer. The electrolytic copper layer is formed by performing an electrolytic copper plating treatment on the copper thin film layer. The laminate obtained in this way has excellent adhesion and bonding between the copper thin film layer and the electrolytic copper layer and the transparent film, and also has excellent transparency after etching, making it suitable for use in flexible printed circuit boards and the like.

[0080] When the laminate according to this embodiment includes an electrolytic copper layer, the thickness of the electrolytic copper layer can be appropriately selected depending on the application of the laminate according to the present invention. However, from the viewpoint of the response speed of wiring in the circuit formed by etching the laminate, the weight and volume of the laminate, etc., a range of 1 μm to 20 μm is preferred, a range of 2 μm to 15 μm is more preferred, and a range of 3 μm to 12 μm is even more preferred.

[0081] (3) Physical properties The physical properties of the laminate according to this embodiment are the same as those described in the first and second embodiments, so they will be omitted here.

[0082] (4) Method for manufacturing the laminate The method for manufacturing the laminate according to this embodiment is described in the same way as the descriptions of the physical properties in the first and second embodiments, so it will be omitted here.

[0083] (5) Use of laminates The laminate according to this embodiment can be subjected to etching to form a conductive pattern. Examples of etching methods include chemical etching and laser etching. The conductive pattern exhibits excellent adhesion and bonding between the transparent resin film substrate layer and the copper thin film layer and electrolytic copper layer laminated thereon, and can therefore be used in applications such as flexible display films, flexible printed circuit boards, flexible heaters, or various electrical appliances utilizing them.

[0084] This technology can also employ the following configuration: [1] A primer composition for forming the primer layer of a laminate in which a base layer, a primer layer, and a copper thin film layer are formed in this order, Containing a photocurable resin or a thermosetting resin, The aforementioned photocurable resin is an acrylate compound, The thermosetting resin is a melamine resin and a polyol. Primer composition. [2] The primer composition according to [1], wherein the polyol is an alkyd polyol. [3] The primer composition according to [1], wherein the acrylate compound is one or more selected from acrylic resin acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and urethane acrylate having 9 or more functional groups. [4] A primer composition according to any of [1] to [3] that satisfies the following requirements. Requirements: When a test specimen is prepared by applying the primer composition to a polyimide film, curing it, and then forming a copper thin film layer on the resulting primer layer by copper sputtering, and a cross-cut test is performed in accordance with JIS K5600-5-6, no delamination of the primer layer and the copper thin film layer from the substrate layer is observed, or the ratio of the area of ​​the primer layer and the copper thin film layer delaminated from the polyimide film to the total area of ​​the test specimen is 5% or less. [5] The primer composition according to any one of [1] to [4], wherein the total light transmittance of the primer layer formed from the primer composition is 86% or more, and the haze value is 1.0% or less. [6] A primer composition according to any one of [1] to [5], wherein the total light transmittance of the primer layer formed from the primer composition after etching is 86% or more, and the haze value after etching is 1.0% or less. [7] A laminate comprising a primer layer formed from any of the primer compositions described in [1] to [6], a copper thin film layer, and a substrate layer, A laminate in which the copper thin film layer and the substrate layer are bonded together by the primer layer.

[0085] 4. Examples Next, the present invention will be specifically described with reference to examples. Note that the examples described below are representative examples of the present invention, and the scope of the present invention is not limited to these examples.

[0086] In this embodiment, the total light transmittance, haze value, adhesion to the polyimide film (primer layer, primer layer and copper thin film layer), and appearance were determined by the measurement method described in the above embodiment.

[0087] (Experimental Example 1) As shown in Table 1 below, a primer composition was prepared containing 80 parts by mass of a 9-functional urethane acrylate (UN-901T, manufactured by Negami Kogyo Co., Ltd.) as a photocurable resin, 190 parts by mass of methyl ethyl ketone as a solvent, and 3 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM).

[0088] Table 1 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 1, with test specimens prepared by the method described above. As shown in Table 1, the primer composition of Experimental Example 1 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0089] (Experimental Example 2) As shown in Table 1 below, a primer composition was prepared containing 100 parts by mass of acrylic resin acrylate (IRR679, manufactured by Daicel Ornex Corporation) as a photocurable resin, 30 parts by mass of pentaerythritol (tri / tetra)acrylate (PETIA, manufactured by Daicel Ornex Corporation), 120 parts by mass of methyl ethyl ketone as a solvent, 60 parts by mass of butyl acetate, and 4 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM Corporation).

[0090] Table 1 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 2, with test specimens prepared by the method described above. As shown in Table 1, the primer composition of Experimental Example 2 exhibited good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0091] (Experimental Example 3) As shown in Table 1 below, a primer composition was prepared containing 100 parts by mass of acrylic resin acrylate (IRR679, manufactured by Daicel Ornex Corporation) as a photocurable resin, 7 parts by mass of pentaerythritol (tri / tetra)acrylate (PETIA, manufactured by Daicel Ornex Corporation), 120 parts by mass of methyl ethyl ketone as a solvent, 60 parts by mass of butyl acetate, and 4 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM Corporation).

[0092] Table 1 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 3, with test specimens prepared by the method described above. As shown in Table 1, the primer composition of Experimental Example 3 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0093] (Experimental Example 4) As shown in Table 1 below, a primer composition was prepared containing 100 parts by mass of 15-functional urethane acrylate (UN-3320HS, manufactured by Negami Kogyo Co., Ltd.) as a photocurable resin, 250 parts by mass of methyl ethyl ketone as a solvent, and 3 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM).

[0094] Table 1 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 4, with test specimens prepared by the method described above. As shown in Table 1, the primer composition of Experimental Example 4 exhibited good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0095] (Experimental Example 5) As shown in Table 1 below, a primer composition was prepared containing 100 parts by mass of acrylic resin acrylate (IRR679, manufactured by Daicel Ornex Corporation) as a photocurable resin, 70 parts by mass of pentaerythritol (tri / tetra)acrylate (PETIA, manufactured by Daicel Ornex Corporation), 120 parts by mass of methyl ethyl ketone as a solvent, 60 parts by mass of butyl acetate, and 4 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM Corporation).

[0096] Table 1 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 5, with test specimens prepared by the method described above. As shown in Table 1, the primer composition of Experimental Example 5 exhibited good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0097] (Experimental Example 6) As shown in Table 1 below, a primer composition was prepared containing 70 parts by mass of hexafunctional urethane acrylate (UN-954, manufactured by Negami Kogyo Co., Ltd.) as a photocurable resin, 130 parts by mass of methyl ethyl ketone as a solvent, and 3 parts by mass of a photopolymerization initiator (IRGACURE 184, manufactured by IGM).

[0098] Table 1 shows the results of measuring various physical properties of test specimens prepared using the primer composition prepared in Experimental Example 6, following the method described above. As shown in Table 1, the adhesion (primer layer) to the polyimide film was not well evaluated in the primer composition of Experimental Example 6.

[0099] [Table 1]

[0100] (Experimental Example 7) As shown in Table 2 below, a primer composition was prepared containing 133 parts by mass of melamine resin (Uban 703, manufactured by Mitsui Chemicals, Inc.) as a thermosetting resin, 30 parts by mass of alkyd polyol (11-408, manufactured by DIC Corporation) as a polyol, and 200 parts by mass of methyl ethyl ketone as a solvent.

[0101] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 7, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 7 exhibited good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), good appearance, and good transparency after etching.

[0102] (Experimental Example 8) As shown in Table 2 below, a primer composition was prepared containing 8.35 parts by mass of melamine resin (Uban 703, manufactured by Mitsui Chemicals, Inc.) as a thermosetting resin, 45 parts by mass of polyether polyol (BPX110, manufactured by ADEKA Corporation) as a polyol, and 200 parts by mass of methyl ethyl ketone as a solvent.

[0103] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 8, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 8 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), and good appearance. However, the haze value after etching was 3.16%, and the transparency evaluation after etching was not good.

[0104] (Experimental Example 9) As shown in Table 2 below, a primer composition was prepared containing 90 parts by mass of pentamethylene diisocyanate (D370-N, manufactured by Mitsui Chemicals, Inc.) as a thermosetting resin, 100 parts by mass of alkyd polyol (11-408, manufactured by DIC Corporation) as a polyol, 0.01 parts by mass of tin catalyst (U-600, manufactured by Nitto Chemical Industries, Ltd.) as a catalyst, and 200 parts by mass of methyl ethyl ketone as a solvent.

[0105] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 9, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 9 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), and good appearance. However, the haze value after etching was 5.9%, and the transparency evaluation after etching was not good.

[0106] (Experimental Example 10) As shown in Table 2 below, a primer composition was prepared containing 100 parts by mass of urethane resin (UR-3500, manufactured by Toyobo Co., Ltd.) as a thermosetting resin and 200 parts by mass of methyl ethyl ketone as a solvent.

[0107] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 10, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 10 showed good adhesion to the polyimide film after the formation of the primer layer (primer layer), adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), and appearance. However, the total light transmittance after the formation of the primer layer was 85.98%, and the haze value after etching was 43.24%, indicating that the transparency evaluation after the formation of the primer layer and after etching was not good.

[0108] (Experimental Example 11) As shown in Table 2 below, a primer composition was prepared containing 100 parts by mass of urethane resin (UR-3500, manufactured by Toyobo Co., Ltd.) as a thermosetting resin and 200 parts by mass of methyl ethyl ketone as a solvent.

[0109] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 11, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 11 did not exhibit good adhesion to the polyimide film (primer layer), the haze value was 28%, and the transparency evaluation was also unsatisfactory.

[0110] (Experimental Example 12) As shown in Table 2 below, a primer composition was prepared containing 100 parts by mass of a modified polyester resin (Washincoat TF1046, manufactured by Washin Chemical Industry Co., Ltd.) as a thermosetting resin, 10 parts by mass of an HDI-based isocyanate (TF-104 curing agent, manufactured by Washin Chemical Industry Co., Ltd.), and 100 parts by mass of methyl ethyl ketone as a solvent.

[0111] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 12, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 12 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), and good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer). However, the appearance after the formation of the copper thin film layer was not good, with a haze value of 20.92% after etching, and the transparency after etching was also not good.

[0112] (Experimental Example 13) As shown in Table 2 below, a primer composition was prepared containing 100 parts by mass of polyamide resin (PA-201, manufactured by T&K TOKA) as a thermosetting resin and 900 parts by mass of methyl ethyl ketone as a solvent.

[0113] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 13, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 13 showed good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), and good appearance. However, the haze value after etching was 14.33%, and the transparency evaluation after etching was not good.

[0114] (Experimental Example 14) As shown in Table 2 below, a primer composition was prepared containing 75 parts by mass of polyamide resin (PA-201, manufactured by T&K TOKA Corporation) as a thermosetting resin, 25 parts by mass of epoxy resin (Epicote 1001, manufactured by Mitsubishi Chemical Corporation), and 900 parts by mass of methyl ethyl ketone as a solvent.

[0115] Table 2 shows the results of measuring various physical properties using the primer composition prepared in Experimental Example 14, with test specimens prepared by the method described above. As shown in Table 2, the primer composition of Experimental Example 14 exhibited good transparency and adhesion to the polyimide film after the formation of the primer layer (primer layer), good adhesion to the polyimide film after the formation of the copper thin film layer (primer layer and copper thin film layer), and good appearance. However, the haze value after etching was 13.5%, and the transparency evaluation after etching was not good.

[0116] [Table 2]

Claims

1. A primer composition for forming the primer layer of a laminate in which a base layer, a primer layer, and a copper thin film layer are formed in this order, Containing a photocurable resin or a thermosetting resin, The aforementioned photocurable resin is an acrylate compound, The thermosetting resin is a melamine resin and a polyol. Primer composition.

2. The primer composition according to claim 1, wherein the polyol is an alkyd polyol.

3. The primer composition according to claim 1, wherein the acrylate compound is one or more selected from acrylic resin acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and urethane acrylate having 9 or more functional groups.

4. A primer composition according to any one of claims 1 to 3, which satisfies the following requirements. Requirements: When a cross-cut test is performed on a test specimen obtained by coating a polyimide film with the primer composition and curing it, and then forming a copper thin film layer on the primer layer by copper sputtering, in accordance with JIS K5600-5-6, no delamination of the primer layer and the copper thin film layer from the substrate layer is observed, or the ratio of the area of ​​the primer layer and the copper thin film layer delaminated from the polyimide film to the total area of ​​the test specimen is 5% or less.

5. The primer composition according to any one of claims 1 to 3, wherein the total light transmittance of the primer layer formed from the primer composition is 86% or more, and the haze value is 1.0% or less.

6. The primer composition according to any one of claims 1 to 3, wherein the total light transmittance of the primer layer formed from the primer composition after etching is 86% or more, and the haze value after etching is 1.0% or less.

7. A laminate comprising a primer layer formed from the primer composition according to any one of claims 1 to 3, a copper thin film layer and a substrate layer, A laminate in which the copper thin film layer and the substrate layer are bonded together by the primer layer.