Laminate

Abstract

Provided is a laminate that has a low haze value and superior heat resistance. This laminate includes a cured resin layer (A), a resin layer, and a cured resin layer (B), in this order. The cured resin layer (A) is a layer comprising a cured product of a curable resin composition 1 that includes a polyimide resin-including polymer component (M) and a curable monomer (P). The cured resin layer (B) is a layer comprising a cured product of a curable resin composition 2 that includes a polymer component (N) and / or a curable monomer (Q).

Description

[Technical Field]

[0001] This invention relates to a laminate. [Background technology]

[0002] In recent years, for various electronic devices requiring optical applications, including liquid crystal displays and organic electroluminescent (EL) displays, there has been a growing interest in using thin, transparent plastic films as substrates for components of these electronic devices, replacing conventional rigid substrates such as glass, in order to achieve thinner, lighter, and more flexible designs. However, plastic films generally have inferior heat resistance compared to glass. For example, transparent plastic films are sometimes used as substrates for forming transparent conductive layers in the aforementioned electronic devices. In this case, the substrate is required to have excellent optical properties at the level of optical films, and then to have excellent heat resistance to high-temperature heating treatments of the conductive layer and the like in the transparent conductive layer formation process. Patent Document 1 discloses, for example, a substrate made of a cured product of a curable resin composition as a substrate for a gas barrier laminate provided together with a transparent conductive layer on the display surface side of a display device or the like. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2020 / 138206 [Overview of the project] [Problems that the invention aims to solve]

[0004] The underlayer in Patent Document 1 is a layer (cured resin layer) made of a cured product of a curable resin composition containing a polymer component (A) such as polyimide resin and a curable monomer (B) such as a (meth)acrylic acid derivative having polymerizable unsaturated bonds. However, it is used in a configuration in which the underlayer is laminated on only one side of the process film (a resin layer such as polyethylene terephthalate), and in the heat treatment (150°C, 1 hour) in the post-processing stage of manufacturing, the oligomer component of the process film precipitates on the side of the process film opposite to the underlayer side, causing a significant increase in the haze value. This may lead to serious problems such as a decrease in the transparency of the configuration, a decrease in the accuracy of defect inspections performed after the post-processing stage, and a decrease in quality and yield due to contamination in the manufacturing process caused by the precipitated oligomer component.

[0005] In view of the above, the present invention aims to provide a laminate with a low haze value and excellent heat resistance. [Means for solving the problem]

[0006] The inventors of the present invention have conducted extensive research to solve the above problems and have found that by providing a specific cured resin layer (B) on the side of the resin layer opposite to the side of the cured resin layer (A) in a laminate comprising a cured resin layer (A), a resin layer, and a cured resin layer (B) in that order, the precipitation of oligomer components of the resin layer can be suppressed, thereby solving the above problems and completing the present invention. In other words, the present invention provides the following [1] to

[11] . [1] A laminate comprising a cured resin layer (A), a resin layer, and a cured resin layer (B) in this order, wherein the cured resin layer (A) is a layer made of a cured product of a curable resin composition 1 containing a polymer component (M) including a polyimide resin and a curable monomer (P), and the cured resin layer (B) is a layer made of a cured product of a curable resin composition 2 containing a polymer component (N) and / or a curable monomer (Q). [2] The laminate according to [1] above, wherein the cured resin layer (B) further contains a filler component. [3] The laminate according to [1] or [2] above, wherein the weight average molecular weight of the polymer component (M) is 100,000 or more. [4] The laminate according to any one of [1] to [3] above, wherein the glass transition temperature of the polymer component (M) is 250°C or more. [5] The laminate according to any one of [1] to [4] above, wherein the thickness of the cured resin layer (A) is 20 μm or less. [6] The laminate according to any one of [1] to [5] above, wherein the haze value of the laminate is 2.0% or less. [7] The laminate according to any one of [1] to [6] above, wherein the haze value of the laminate after heating at 150°C for 1 hour is 2.0% or less. [8] The laminate according to any one of [1] to [7] above, wherein the peel strength between the cured resin layer (A) and the resin layer after heating at 150°C for 1 hour is 500 mN / 50 mm or less and 30 mN / 50 mm or more. [9] The laminate according to any one of [1] to [8] above, further comprising a release layer between the cured resin layer (A) and the resin layer, and the peel strength between the cured resin layer (A) and the release layer after heating at 150°C for 1 hour is 500 mN / 50 mm or less and 30 mN / 50 mm or more.

[10] The laminate according to any one of [1] to [9] above, wherein the resin layer is a polyester film or a polyolefin film.

[11] The laminate according to any one of [1] to

[10] above, further comprising a functional layer on one or both surfaces of the cured resin layer (A). [Effect of the Invention]

[0007] According to the present invention, a laminate having a low haze value and excellent heat resistance can be provided. [Brief Description of the Drawings]

[0008] [Figure 1] It is a cross-sectional view showing an example of the laminate of the present invention. [Figure 2] It is a cross-sectional view showing another example of the laminate of the present invention. [Mode for Carrying Out the Invention]

[0009] In this specification, any provision deemed preferable can be selected at will, and any combination of preferred provisions is considered more preferable. In this specification, the notation "XX~YY" means "XX or greater and YY or less". In this specification, the lower and upper limits described in steps for a preferred numerical range (e.g., range of content, etc.) can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to arrive at "10 to 60". In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms.

[0010] [Laminated structure] The present invention is a laminate comprising a cured resin layer (A), a resin layer, and a cured resin layer (B) in this order, wherein the cured resin layer (A) is a layer made of a cured product of a curable resin composition 1 containing a polymer component (M) including a polyimide resin and a curable monomer (P), and the cured resin layer (B) is a layer made of a cured product of a curable resin composition 2 containing a polymer component (N) and / or a curable monomer (Q). In the present invention, in a laminate comprising a cured resin layer (A), a resin layer, and a cured resin layer (B) in this order, a cured resin layer (B) (hereinafter sometimes referred to as "process film 2") made of a cured product of a curable resin composition 2 containing a polymer component (N) and / or a curable monomer (Q) is laminated on the side of the resin layer (hereinafter sometimes referred to as "process film 1") opposite to the side facing the cured resin layer (A). This makes it possible to suppress the precipitation of oligomer components of the resin layer due to prolonged heating treatment at high temperatures. As a result, the increase in the haze value of the laminate is suppressed, and the decrease in defect inspection accuracy in subsequent processes, as well as the decrease in quality and yield due to contamination occurring during the manufacturing process, can be eliminated.

[0011] Figure 1 is a cross-sectional view showing an example of the laminate of the present invention. Laminate 1 is composed of cured resin layer (A) 2, resin layer 3, and cured resin layer (B) 4 in this order. By providing cured resin layer (B) 4, which is process film 2, on the side of resin layer 3, which is process film 1, opposite to the side facing cured resin layer (A) 2, it is possible to suppress not only the precipitation of oligomer components from resin layer 3 into cured resin layer (B) 4 due to prolonged heating treatment at high temperatures, but also the precipitation of oligomer components into cured resin layer (A) 2. As a result, the increase in the haze value of laminate 1 is suppressed, and naturally the same applies to cured resin layer (A) 2 after peeling off process film 1.

[0012] The haze value of the laminate is preferably 3.0% or less, more preferably 2.0% or less, even more preferably 1.5% or less, and particularly preferably 1.0% or less. The haze value of the laminate after heating at 150°C for 1 hour is preferably 3.0% or less, more preferably 2.0% or less, even more preferably 1.5% or less, and particularly preferably 1.0% or less. When the haze value is within this range, for example, when a functional layer described later is formed and the laminate is constructed, it becomes easier to maintain low light diffusion in the entire laminate, and it becomes possible to improve the accuracy of detecting defects such as scratches and foreign matter present in the cured resin layer (A) during defect inspection of the cured resin layer (A). The haze value was measured using the method described in the examples below.

[0013] The peeling force between the cured resin layer (A) and the resin layer after heating at 150°C for 1 hour is preferably 500 mN / 50 mm or less, more preferably 400 mN / 50 mm or less, even more preferably 300 mN / 50 mm or less, and particularly preferably 250 mN / 50 mm or less. Furthermore, as will be described later, a release layer may be provided between the cured resin layer (A) and the resin layer. The peeling force between the cured resin layer (A) and the release layer after heating at 150°C for 1 hour is preferably 500 mN / 50 mm or less, more preferably 400 mN / 50 mm or less, even more preferably 300 mN / 50 mm or less, and particularly preferably 250 mN / 50 mm or less. Furthermore, the peeling force between the cured resin layer (A) and the resin layer or release layer after heating at 150°C for 1 hour is preferably 20 mN / 50 mm or more, more preferably 30 mN / 50 mm or more, even more preferably 50 mN / 50 mm or more, and particularly preferably 70 mN / 50 mm or more. When the peeling force is within this range, the process film does not peel off during web handling, and the cured resin layer (A) can be easily peeled off from the resin layer as process film 1, both before and after heat treatment. The peeling force was measured using the method described in the examples below.

[0014] The thickness of the laminate, including the functional layer described later, can be appropriately determined depending on the intended application, such as the substrate or electronic device. From the viewpoint of ease of handling, the thickness of the laminate is preferably 5 to 300 μm, more preferably 20 to 250 μm, and even more preferably 50 to 200 μm.

[0015] (Functional layer) In one aspect of the present invention, it is preferable to further provide a functional layer on one or both surfaces of the cured resin layer (A). Figure 2 is a cross-sectional view showing another example of the laminate of the present invention. In Figure 2, the laminate 11 consists of a cured resin layer (A) 2, a resin layer 3, a cured resin layer (B) 4, and a functional layer 5. That is, the functional layer 5 is laminated on the cured resin layer (A) 2, and the cured resin layer (A) 2 can be used as a layer on which the functional layer 5 is provided or as a base material.

[0016] The functional layers are not particularly limited, but examples include conductive layers, adhesive layers, tack layers, adhesive-backed layers, gas barrier layers, shock-absorbing layers, hard coat layers, and anti-reflective layers. The placement of the functional layers is not particularly limited.

[0017] For example, materials that constitute a conductive layer (electrode, transparent conductive layer, etc.) used as a functional layer include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Examples of transparent conductive layers include antimony-doped tin oxide (ATO); fluorine-doped tin oxide (FTO); semiconducting metal oxides such as tin oxide, germanium-doped zinc oxide (GZO), zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide (IZO); metals such as gold, silver, chromium, and nickel; mixtures of these metals and conductive metal oxides; inorganic conductive substances such as copper iodide and copper sulfide; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole. Methods for forming the conductive layer include, for example, printing, vapor deposition, sputtering, ion plating, thermal CVD, and plasma CVD. The thickness of the conductive layer can be appropriately selected depending on the application. Typically, it is 10 nm to 50 μm, preferably 20 nm to 20 μm.

[0018] The adhesive layer is a layer used, for example, when attaching a laminate to an object. The material used to form the adhesive layer is not particularly limited, and known adhesives or sealants such as acrylic, silicone, rubber, and epoxy adhesives, as well as heat sealing materials, can be used. Epoxy adhesives are preferred as the material constituting the adhesive layer. Similarly, the adhesive layer is a layer used, for example, when attaching a laminate to an object. Examples of adhesives used in the adhesive layer include acrylic adhesives, urethane adhesives, silicone adhesives, and rubber adhesives. Among these, acrylic adhesives and urethane adhesives are preferred in terms of adhesive strength, transparency, and ease of handling. Adhesives that can form a crosslinked structure are also preferred. The adhesive may be in any form, such as a solvent-type adhesive, emulsion-type adhesive, or hot-melt-type adhesive.

[0019] The thickness of a laminate including a functional layer is typically the sum of the thickness of the target functional layer and the thickness of the laminate without the functional layer.

[0020] <Cured resin layer (A)> The laminate of the present invention includes a cured resin layer (A). The cured resin layer (A) is a layer made of a cured product of a curable resin composition 1 containing a polymer component (M) including a polyimide resin and a curable monomer (P). The cured resin layer (A) may be a single layer or multiple layers. The method for forming the cured resin layer (A) will be described in detail later in the section on the manufacturing method of the laminate.

[0021] (Polymer component (M)) The polymer component (M) contains a polyimide resin. Polyimide resins have a high glass transition temperature (Tg) and excellent heat resistance. Furthermore, because they allow for coating film formation by solution casting and readily yield a cured resin layer (A) with excellent optical isotropy, it is preferable that the polyimide resin be amorphous thermoplastic. Furthermore, while polyimide resin exhibits heat resistance, it is soluble in common organic solvents, such as low-boiling point organic solvents like benzene and methyl ethyl ketone. Here, amorphous thermoplastic resin refers to a thermoplastic resin in which no melting point is observed in differential scanning calorimetry.

[0022] The glass transition temperature of the polymer component (M) is preferably 250°C or higher, more preferably 290°C or higher, and even more preferably 320°C or higher. By using a polymer component (M) with a Tg of 250°C or higher, sufficient heat resistance can be imparted to the cured resin layer (A). For example, when forming a functional layer from a coating film, the cured resin layer (A) is less likely to be affected and deform due to heating during coating (including solvent drying, etc.), and as a result, the functional layer of the laminate can fully exhibit its inherent functions. A coating film is a film obtained by applying a coating material to a substrate or object and, if necessary, performing curing treatments such as drying or heating. When a functional layer is considered a coating film, it is a film obtained by applying a coating material containing components that form the functional layer onto a cured resin layer (A) and performing curing treatments by drying and / or heating, irradiation with active energy rays, or both. Here, Tg refers to the temperature at which tanδ (loss modulus / storage modulus) is maximized, obtained by viscoelastic measurement (measurement in tensile mode in the range of 0 to 400°C at a frequency of 10 Hz and a heating rate of 3°C / min).

[0023] The weight-average molecular weight (Mw) of the polyimide resin in the polymer component (M) is preferably 100,000 or more, more preferably 100,000 or more and 280,000 or less, and even more preferably 100,000 or more and 240,000 or less. When the weight-average molecular weight (Mw) is within this range, for example, when forming a functional layer from a coating film, thermal shrinkage of the cured resin layer (A) before and after heating (including solvent drying, etc.) during coating of the coating film is suppressed, and as a result, the functional layer of the laminate can fully exhibit its inherent functions. Furthermore, the molecular weight distribution (Mw / Mn) is preferably in the range of 1.0 to 5.0, and more preferably in the range of 1.2 to 3.0. The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are polystyrene-converted values ​​measured by gel permeation chromatography (GPC).

[0024] The polyimide resin is not particularly limited as long as it does not impair the effects of the present invention, but for example, aromatic polyimide resins, aromatic (carboxylic acid component)-cyclic aliphatic (diamine component) polyimide resins, cyclic aliphatic (carboxylic acid component)-aromatic (diamine component) polyimide resins, cyclic aliphatic polyimide resins, and fluorinated aromatic polyimide resins can be used. Among these, a polyimide resin having an aromatic ring structure is preferred in one embodiment. In another embodiment, a polyimide resin having a fluoro group in the molecule, as described later, is preferred. Specifically, polyimide resins obtained by polymerization of an aromatic diamine compound and a tetracarboxylic dianhydride into a polyamic acid and then through a chemical imidation reaction are preferred.

[0025] Any aromatic diamine compound can be used as the aromatic diamine compound, as long as it reacts with the tetracarboxylic dianhydride used in conjunction with the compound to yield a polyimide that is soluble in a common solvent (e.g., N,N-dimethylacetamide (DMAC)) and has the desired transparency. Specifically, m-phenylenediamine, p-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2-(3- Minophenyl)-2-(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl)-2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 3,4'-Bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenyl)]sulfone, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[ 4-(3-aminophenyl)]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, 2,2-bis[4 -(4-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3 Examples include 3,3-hexafluoropropane, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl.

[0026] These aromatic diamine compounds may be used individually or in combination of two or more aromatic diamine compounds. From the viewpoint of transparency and heat resistance, preferred aromatic diamine compounds include 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2-(3-aminophenyl)-2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3 Examples of aromatic diamine compounds having a fluoro group include ,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. Preferably, at least one of the aromatic diamine compounds used is an aromatic diamine compound having a fluoro group, and particularly preferably 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. By using an aromatic diamine compound having a fluoro group, transparency, heat resistance, and solubility in solvents can be easily obtained.

[0027] As the tetracarboxylic dianhydride, any tetracarboxylic dianhydride that is soluble in a common solvent (e.g., N,N-dimethylacetamide (DMAC)) and yields a polyimide with predetermined transparency can be used, similar to the aromatic diamine compounds mentioned above. Specifically, examples include 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphthalic acid dianhydride, pyromellitic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 1,4-hydroquinone dibenzoate-3,3',4,4'-tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride. These tetracarboxylic dianhydrides may be used individually or in combination of two or more types. Furthermore, from the viewpoint of transparency, heat resistance, and solubility in solvents, it is preferable to use a tetracarboxylic dianhydride having at least one fluoro group, such as 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphthalic acid dianhydride.

[0028] Polymerization to polyamic acid can be carried out by reacting the above-mentioned aromatic diamine compound and tetracarboxylic dianhydride under conditions of dissolution of the resulting polyamic acid in a solvent. Suitable solvents for polymerization to polyamic acid include N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and dimethyl sulfoxide.

[0029] Polymerization reactions to polyamic acid are preferably carried out in a reaction vessel equipped with a stirring device while stirring. For example, methods include dissolving a predetermined amount of aromatic diamine compound in the solvent and adding tetracarboxylic dianhydride while stirring to carry out the reaction and obtain polyamic acid; dissolving tetracarboxylic dianhydride in a solvent and adding aromatic diamine compound while stirring to carry out the reaction and obtain polyamic acid; and alternately adding aromatic diamine compound and tetracarboxylic dianhydride to carry out the reaction and obtain polyamic acid.

[0030] There are no particular restrictions on the temperature of the polymerization reaction to polyamic acid, but it is preferably carried out at a temperature of 0 to 70°C, more preferably at 10 to 60°C, and even more preferably at 20 to 50°C. By carrying out the polymerization reaction within the above range, it is possible to obtain high molecular weight polyamic acid with less discoloration and excellent transparency.

[0031] Furthermore, while the aromatic diamine compound and tetracarboxylic dianhydride used in polymerization to polyamic acid are generally used in roughly equal molar amounts, it is also possible to vary the molar ratio of tetracarboxylic dianhydride to aromatic diamine compound (molar ratio) within the range of 0.95 to 1.05 in order to control the degree of polymerization of the resulting polyamic acid. Preferably, the molar ratio of tetracarboxylic dianhydride to aromatic diamine compound is in the range of 1.001 to 1.020, and more preferably 1.001 to 1.010. By using a slight excess of tetracarboxylic dianhydride relative to the aromatic diamine compound in this way, the degree of polymerization of the resulting polyamic acid can be stabilized, and units derived from tetracarboxylic dianhydride can be placed at the ends of the polymer, resulting in a polyimide with less coloration and excellent transparency.

[0032] The concentration of the resulting polyamic acid solution is preferably adjusted to an appropriate concentration (for example, about 10-30% by mass) to maintain the viscosity of the solution properly and facilitate handling in subsequent processes.

[0033] An imidizing agent is added to the obtained polyamic acid solution to carry out a chemical imidation reaction. As the imidizing agent, carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, succinic anhydride, phthalic anhydride, and benzoic anhydride can be used, and acetic anhydride is preferred from the viewpoint of cost and ease of removal after the reaction. The equivalent amount of imidizing agent used is equal to or greater than the equivalent amount of the amide bond of the polyamic acid undergoing the chemical imidation reaction, and is preferably 1.1 to 5 times the equivalent amount of the amide bond, and more preferably 1.5 to 4 times. By using a slightly excess amount of imidizing agent relative to the amide bond in this way, the imidation reaction can be carried out efficiently even at relatively low temperatures.

[0034] For chemical imidation reactions, aliphatic, aromatic, or heterocyclic tertiary amines such as pyridine, picoline, quinoline, isoquinoline, trimethylamine, and triethylamine can be used as imidation accelerators. Using such amines allows for efficient imidation reactions at low temperatures, which in turn suppresses discoloration during the reaction and makes it easier to obtain more transparent polyimides.

[0035] There are no particular restrictions on the temperature of the chemical imidation reaction, but it is preferable to carry it out at a temperature of 10°C or higher but less than 50°C, and more preferably at a temperature of 15°C or higher but less than 45°C. By carrying out the chemical imidation reaction at a temperature of 10°C or higher but less than 50°C, discoloration during the imidation reaction can be suppressed, and a polyimide with excellent transparency can be obtained.

[0036] After this, if necessary, a poor solvent for polyimide is added to the polyimide solution obtained by the chemical imidation reaction to precipitate the polyimide and form a powder, followed by pulverization and drying.

[0037] The polyimide resin is preferably soluble in low-boiling point organic solvents such as benzene or methyl ethyl ketone. In particular, it is preferably soluble in methyl ethyl ketone. If it is soluble in methyl ethyl ketone, a cured resin layer (A), described later, consisting of the cured product of curable resin composition 1, can be easily formed by coating and drying.

[0038] Polyimide resins containing fluorogroups are particularly preferred because they readily dissolve in general-purpose organic solvents with low boiling points, such as methyl ethyl ketone, and facilitate the formation of a curable resin layer by coating methods. As for polyimide resins having fluorogroups, aromatic polyimide resins having fluorogroups in the molecule are preferred, and those having a skeleton represented by the following chemical formula in the molecule are preferred. [ka]

[0039] The polyimide resin having the skeleton shown in the above chemical formula has an extremely high Tg exceeding 300°C due to the high rigidity of the skeleton. Therefore, the heat resistance of the cured resin layer (A) can be greatly improved. Furthermore, the skeleton is linear and relatively flexible, making it easy to increase the elongation at break (A) of the cured resin layer. In addition, the polyimide resin having the above skeleton can dissolve in low-boiling point general-purpose organic solvents such as methyl ethyl ketone due to the presence of fluoro groups. Therefore, coating can be performed using the solution casting method to form a cured resin layer (A) as a coating film, and solvent removal by drying is also easy. The polyimide resin having the skeleton shown in the above chemical formula can be obtained by polymerization and imidization reactions of the polyamic acid described above using 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl and 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphthalic acid dianhydride.

[0040] The polymer component (M) may also contain other components. Examples of other components include polyarylate resins. Polyarylate resins are polymeric compounds obtained by the reaction of aromatic diols with aromatic dicarboxylic acids or their chlorides. Like polyimide resins, polyarylate resins have a relatively high Tg and relatively good elongation properties. The polyarylate resin is not particularly limited, and known types can be used.

[0041] Examples of aromatic diols include bis(4-hydroxyphenyl)methane [bisphenol F], bis(3-methyl-4-hydroxyphenyl)methane, 1,1-bis(4'-hydroxyphenyl)ethane, 1,1-bis(3'-methyl-4'-hydroxyphenyl)ethane, 2,2-bis(4'-hydroxyphenyl)propane [bisphenol A], 2,2-bis(3'-methyl-4'-hydroxyphenyl)propane, 2,2-bis(4'-hydroxyphenyl)butane, 2,2-bis(4'-hydroxyphenyl)octane, and other bis(hydroxyphenyl)alkanes; and bis(hydroxyphenyl)cycloalkanes such as 1,1-bis(4'-hydroxyphenyl)cyclopentane, 1,1-bis(4'-hydroxyphenyl)cyclohexane [bisphenol Z], and 1,1-bis(4'-hydroxyphenyl)-3,3,5-trimethylcyclohexane.Bis(4-hydroxyphenyl)phenylmethane, bis(3-methyl-4-hydroxyphenyl)phenylmethane, bis(2,6-dimethyl-4-hydroxyphenyl)phenylmethane, bis(2,3,6-trimethyl-4-hydroxyphenyl)phenylmethane, bis(3-t-butyl-4-hydroxyphenyl)phenylmethane, bis(3-phenyl-4-hydroxyphenyl)phenylmethane, bis(3-fluoro-4-hydroxyphenyl)phenylmethane, bis(3-bromo-4-hydroxyphenyl)phenyl Methane, bis(4-hydroxyphenyl)-4-fluorophenylmethane, bis(3-fluoro-4-hydroxyphenyl)-4-fluorophenylmethane, bis(4-hydroxyphenyl)-4-chlorophenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethyl-4-hydroxyphenyl)-4-fluorophenylmethane, 1,1-bis(4'-hydroxyphenyl)-1-phenylethane [bisphenol P], 1,1-bis(3'-methyl-4'-hydroxyphenyl )-1-phenylethane, 1,1-bis(3'-t-butyl-4'-hydroxyphenyl)-1-phenylethane, 1,1-bis(3'-phenyl-4'-hydroxyphenyl)-1-phenylethane, 1,1-bis(4'-hydroxyphenyl)-1-(4'-nitrophenyl)ethane, 1,1-bis(3'-bromo-4'-hydroxyphenyl)-1-phenylethane, 1,1-bis(4'-hydroxyphenyl)-1-phenylpropane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl Bis(hydroxyphenyl)phenylalkanes such as phenyl)dibenzylmethane; bis(hydroxyphenyl) ethers such as bis(4-hydroxyphenyl) ether and bis(3-methyl-4-hydroxyphenyl) ether; bis(hydroxyphenyl) ketones such as bis(4-hydroxyphenyl) ketone and bis(3-methyl-4-hydroxyphenyl) ketone; bis(hydroxyphenyl) sulfides such as bis(4-hydroxyphenyl) sulfide and bis(3-methyl-4-hydroxyphenyl) sulfide;Examples include bis(hydroxyphenyl) sulfoxides such as bis(4-hydroxyphenyl) sulfoxide and bis(3-methyl-4-hydroxyphenyl) sulfoxide; bis(hydroxyphenyl) sulfones such as bis(4-hydroxyphenyl) sulfone [bisphenol S] and bis(3-methyl-4-hydroxyphenyl) sulfone; and bis(hydroxyphenyl) fluorenes such as 9,9-bis(4'-hydroxyphenyl) fluorene and 9,9-bis(3'-methyl-4'-hydroxyphenyl) fluorene.

[0042] Examples of aromatic dicarboxylic acids or their chlorides include phthalic acid, isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyl ether 4,4'-dicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and their chlorides. The polyarylate resin used may also be a modified polyarylate resin. Among these, a resin made from a polymer compound obtained by the reaction of 2,2-bis(4'-hydroxyphenyl)propane with isophthalic acid is preferred as the polyarylate resin.

[0043] Polymer component (M) can be used alone or in combination of two or more types. Alternatively, polymer component (M) may be used in combination with polymer component (M') having a glass transition temperature of less than 250°C. Examples of polymer component (M') include polyamide resins and polyarylate resins with a Tg of less than 250°C, with polyamide resins being preferred.

[0044] The polyamide resin is preferably soluble in organic solvents, and rubber-modified polyamide resins are preferred. As a rubber-modified polyamide resin, for example, the one described in Japanese Patent Application Publication No. 2004-035638 can be used.

[0045] From the viewpoint of being able to adjust the elongation properties and solvent resistance, polymer components (M) and polymer components (M') that use a single type of polyimide resin, multiple types of different polyimide resins, and polyimide resins to which at least one of polyamide resin and polyarylate resin is added are preferred.

[0046] When adding polyamide resin or polyarylate resin with a Tg of less than 250°C to polyimide resin, the amount of resin added is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of polyimide resin, from the viewpoint of maintaining a high Tg while providing appropriate flexibility.

[0047] (Curable monomer (P)) A curable monomer (P) is a monomer having polymerizable unsaturated bonds and capable of participating in polymerization reactions, or polymerization reactions and crosslinking reactions. In this specification, "curing" refers to a broad concept that includes "polymerization reactions of monomers," or "polymerization reactions of monomers and subsequent crosslinking reactions of polymers."

[0048] The molecular weight of the curable monomer (P) is usually 3,000 or less, preferably 150 to 2,000, and more preferably 150 to 1,000. The number of polymerizable unsaturated bonds in the curable monomer (P) is not particularly limited. The curable monomer (P) may be a monofunctional monomer having one polymerizable unsaturated bond, or a polyfunctional monomer such as a 2- to 6-functional monomer having multiple polymerizable unsaturated bonds.

[0049] Examples of the aforementioned monofunctional monomers include monofunctional (meth)acrylic acid derivatives. The monofunctional (meth)acrylic acid derivative is not particularly limited, and known compounds can be used. For example, a monofunctional (meth)acrylic acid derivative having a nitrogen atom, a monofunctional (meth)acrylic acid derivative having an alicyclic structure, a monofunctional (meth)acrylic acid derivative having a polyether structure, etc. can be mentioned.

[0050] Examples of the monofunctional (meth)acrylic acid derivative having a nitrogen atom include compounds represented by the following formula.

[0051]

Chemical formula

[0052] In the formula, R 1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R 2 and R 3 each independently represent a hydrogen atom or an organic group having 1 to 12 carbon atoms, R 2 and R 3 may combine to form a ring structure, R 4 represents a divalent organic group. Examples of the alkyl group having 1 to 6 carbon atoms represented by R 1 include a methyl group, an ethyl group, a propyl group, etc., and a methyl group is preferred. Examples of the organic group having 1 to 12 carbon atoms represented by R 2 and R 3 include an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, etc.; a cycloalkyl group having 3 to 12 carbon atoms such as a cyclopentyl group, a cyclohexyl group, etc.; an aromatic group having 6 to 12 carbon atoms such as a phenyl group, a biphenyl group, a naphthyl group, etc. These groups may have substituents at any position. Also, R 2 and R 3 may combine to form a ring, and the ring may further have a nitrogen atom or an oxygen atom in the skeleton. Examples of the divalent organic group represented by R 4 include -(CH2) m -, -NH-(CH2) mA base represented by - is given, where m is an integer from 1 to 10.

[0053] Among these, (meth)acryloylmorpholine, represented by the following formula, is a preferred monofunctional (meth)acrylic acid derivative having a nitrogen atom.

[0054] [ka]

[0055] By using a monofunctional (meth)acrylic acid derivative containing a nitrogen atom as the curable monomer (P), a curable resin layer with superior heat resistance can be formed.

[0056] Examples of monofunctional (meth)acrylic acid derivatives having an alicyclic structure include compounds represented by the following formula.

[0057] [ka]

[0058] In the formula, R 1 This has the same meaning as above, R 5 It is a group having an alicyclic structure. R 5 Groups having an alicyclic structure represented by include cyclohexyl group, isobornyl group, 1-adamantyl group, 2-adamantyl group, and tricyclodecanyl group.

[0059] Specific examples of monofunctional (meth)acrylic acid derivatives having an alicyclic structure include isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 1-adamantyl (meth)acrylate, and 2-adamantyl (meth)acrylate.

[0060] By using a monofunctional (meth)acrylic acid derivative having an alicyclic structure as the curable monomer (P), a cured resin layer (P) with superior optical properties can be formed.

[0061] Examples of monofunctional (meth)acrylic acid derivatives having a polyether structure include compounds represented by the following formula.

[0062] [ka]

[0063] In the formula, R 1 This has the same meaning as above, R 6 R represents an organic group with 1 to 12 carbon atoms. 6 Examples of organic groups with 1 to 12 carbon atoms represented by include alkyl groups with 1 to 12 carbon atoms such as methyl, ethyl, and propyl groups; cycloalkyl groups with 3 to 12 carbon atoms such as cyclohexyl groups; and aromatic groups with 6 to 12 carbon atoms such as phenyl, biphenyl, and naphthyl groups. j represents an integer from 2 to 20.

[0064] Specific examples of monofunctional (meth)acrylic acid derivatives having a polyether structure include ethoxylated o-phenylphenol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and phenoxypolyethylene glycol (meth)acrylate.

[0065] By using a monofunctional (meth)acrylic acid derivative having a polyether structure as a curable monomer (P), a cured resin layer (A) with excellent toughness can be formed.

[0066] Examples of the aforementioned polyfunctional monomers include polyfunctional (meth)acrylic acid derivatives. The polyfunctional (meth)acrylic acid derivative is not particularly limited, and known compounds can be used. For example, 2- to 6-functional (meth)acrylic acid derivatives can be used. Examples of bifunctional (meth)acrylic acid derivatives include compounds represented by the following formula.

[0067] [ka]

[0068] In the formula, R 1 This has the same meaning as the above, R 7 R represents a divalent organic group. 7 Examples of divalent organic groups represented by the formula below include the group shown in the following formula.

[0069] [ka]

[0070] (In the expression, s represents an integer between 1 and 20, t represents an integer between 1 and 30, u and v each independently represent an integer between 1 and 30, and the "-" at both ends represents a combination.)

[0071] Specific examples of the bifunctional (meth)acrylic acid derivative represented by the above formula include tricyclodecanedimethanol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, urethane acrylate, etc. Among these, tricyclodecanedimethanol di(meth)acrylate and others are considered to have good heat resistance and toughness, and in the above formula, R 7 In the above formula, the divalent organic group represented by has a tricyclodecane skeleton, propoxylated ethoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, etc., R 7 The divalent organic group represented by has a bisphenol skeleton, such as 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, in the above formula, R 7 The divalent organic group represented by has a 9,9-bisphenylfluorene skeleton, which is preferable. From the viewpoint of imparting flexibility, urethane acrylate is preferred.

[0072] Other examples of difunctional (meth)acrylic acid derivatives include neopentyl glycol adipate di(meth)acrylate, neopentyl glycol di(meth)acrylate hydroxypivalate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, di(acryloxyethyl) isocyanurate, and allylated cyclohexyl di(meth)acrylate.

[0073] Examples of trifunctional (meth)acrylic acid derivatives include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, and tris(acryloxyethyl) isocyanurate. Examples of tetrafunctional (meth)acrylic acid derivatives include pentaerythritol tetra(meth)acrylate. Examples of pentafunctional (meth)acrylic acid derivatives include propionic acid-modified dipentaerythritol penta(meth)acrylate. Examples of hexafunctional (meth)acrylic acid derivatives include dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0074] A cyclopolymerizable monomer may be used as the curable monomer (P). A cyclopolymerizable monomer is a monomer that has the property of undergoing radical polymerization while cyclizing. Examples of cyclopolymerizable monomers include non-conjugated dienes, for example, α-allyloxymethylacrylic acid monomers can be used, with alkyl esters of 2-allyloxymethylacrylic acid having 1 to 4 carbon atoms and cyclohexyl 2-(allyloxymethyl)acrylate being preferred, alkyl esters of 2-allyloxymethylacrylic acid having 1 to 4 carbon atoms being more preferred, and methyl 2-(allyloxymethyl)acrylate being even more preferred. In addition, cyclopolymerizable monomers such as dimethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, diethyl-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-propyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(i-propyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-butyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, di(n-hexyl)-2,2'-[oxybis(methylene)]bis-2-propenoate, and dicyclohexyl-2,2'-[oxybis(methylene)]bis-2-propenoate can also be used.

[0075] The curable monomer (P) can be used alone or in combination of two or more types. Among these, a polyfunctional monomer is preferred as the curable monomer (P) because it yields a cured resin layer (A) with superior heat resistance and solvent resistance. As a polyfunctional monomer, a bifunctional (meth)acrylic acid derivative is preferred from the viewpoint of being easily mixed with the polymer component (M), less prone to curing shrinkage of the polymer, and suppressing curling of the cured product. It is more preferable that the curable monomer (P) includes a polyfunctional (meth)acrylate compound and a cyclopolymerizable monomer. By using these in combination, it becomes easier to adjust the elongation at break of the curable resin layer (A) while appropriately adjusting the heat resistance of the curable resin layer. When the curable monomer (P) contains polyfunctional monomers, the content of these monomers is preferably 40% by mass or more, and more preferably 50 to 100% by mass, of the total amount of curable monomer (P).

[0076] <Curable resin composition 1> The curable resin composition 1 used in the present invention can be prepared by mixing a polymer component (M), a curable monomer (P), and optionally a polymerization initiator or other components described later, and dissolving or dispersing them in a suitable solvent.

[0077] The total content of polymer components (M) and curable monomers (P) in the curable resin composition 1 is preferably 40 to 99.5% by mass, more preferably 60 to 99% by mass, and even more preferably 80 to 98% by mass, based on the total mass of the curable resin composition 1 excluding the solvent.

[0078] The content of polymer component (M) and curable monomer (P) in the curable resin composition 1 is preferably such that the mass ratio of polymer component (M) to curable monomer (P) is 20:80 to 90:10, and more preferably 30:70 to 70:30. In curable resin composition 1, when the mass ratio of polymer component (M) to curable monomer (P) is within this range, the thermal shrinkage rate of the curable resin layer (A) before and after high-temperature heat treatment tends to decrease, and the elongation at break tends to be maintained. Furthermore, the polyimide resin content in the polymer component (M) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total mass of the polymer component (M) excluding the solvent.

[0079] When using a combination of multiple resins with different solvent solubility as the polymer component (M), such as a combination of the polyimide resin mentioned above with a polyamide resin or a polyarylate resin, it is preferable to first dissolve each resin in a solvent suitable for that solvent, and then add the solution of the other resin to the low-boiling point organic solvent in which the resins are dissolved.

[0080] The curable resin composition 1 may optionally contain a polymerization initiator. The polymerization initiator can be any agent that initiates the curing reaction, and examples include thermal polymerization initiators and photopolymerization initiators.

[0081] Examples of thermal polymerization initiators include organic peroxides and azo compounds. Examples of organic peroxides include dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide; diacyl peroxides such as acetyl peroxide, lauroyl peroxide, and benzoyl peroxide; ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; and peroxy such as 1,1-bis(t-butylperoxy)cyclohexane. Examples include ketals; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, and 2,5-dimethylhexane-2,5-dihydroperoxide; and peroxyesters such as t-butyl peroxyacetate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, and t-butyl peroxyisopropyl carbonate. Examples of azo compounds include 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 2-(carbamoylazo)isobutyronitrile, and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile.

[0082] Examples of photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl]-2-methyl-propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamine. Alkylphenone-based photopolymerization initiators such as no-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone; phosphorus-based photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)-phenylphosphine, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; bis(η 5Titanocene-based photopolymerization initiators such as -2,4-cyclopentadiene-1-yl)-bis[2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl]titanium; oxime ester-based photopolymerization initiators such as 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyl oxime)], etanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime); benzophenone, p-chlorobenzophenone, benzoylbenzoic acid, o-methylbenzoylbenzoate, 4-methylbenzophenone, 4-phenylbenzophenone, hydroxybenzophenone, acrylic benzophenone, 4-benzoyl Examples include benzophenone-based photopolymerization initiators such as 4'-methyl-diphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone, and 4-(13-acryloyl-1,4,7,10,13-pentaoxatridecyl)-benzophenone; and thioxanthone-based photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone.

[0083] Among the above photopolymerization initiators, phosphorus-based photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)-phenylphosphine, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide are preferred. The polymer component (M) absorbs ultraviolet light, which can make the curing reaction difficult. If the polymer component (M) is a resin containing an aromatic ring, the above-mentioned phosphorus-based photopolymerization initiator can be used to efficiently promote the curing reaction by utilizing light of wavelengths that are not absorbed by the polymer component (M). Polymerization initiators can be used individually or in combination of two or more.

[0084] The polymerization initiator content is preferably 0.05 to 15% by mass, more preferably 0.05 to 10% by mass, and even more preferably 0.05 to 5% by mass, relative to the total curable resin composition 1.

[0085] Furthermore, in addition to the polymer component (M), curable monomer (P), and polymerization initiator, the curable resin composition 1 may also contain photopolymerization initiators such as triisopropanolamine and 4,4'-diethylaminobenzophenone.

[0086] The solvent used in preparing the curable resin composition 1 is not particularly limited and includes, for example, aliphatic hydrocarbon solvents such as n-hexane and n-heptane; aromatic hydrocarbon solvents such as toluene and xylene; halogenated hydrocarbon solvents such as dichloromethane, ethylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, and monochlorobenzene; alcoholic solvents such as methanol, ethanol, propanol, butanol, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esteric solvents such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve; and etheric solvents such as 1,3-dioxolane.

[0087] The solvent content in the curable resin composition 1 is not particularly limited, but is usually 0.1 to 1,000 g, preferably 1 to 100 g, per 1 g of polymer component (M). The viscosity of the curable resin composition 1 can be adjusted to an appropriate level by appropriately adjusting the amount of solvent.

[0088] Furthermore, the curable resin composition 1 may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, to the extent that they do not impair the objectives and effects of the present invention.

[0089] <Properties of the cured resin layer (A)> The cured resin layer (A) used in the present invention exhibits thermal shrinkage (shrinkage upon heating). The thermal shrinkage rate when heat-treated at 100°C for 2 minutes is preferably 0.08% or less, more preferably 0.05% or less, and even more preferably 0.01% or less. When the thermal shrinkage rate of the curable resin layer is within this range, the heat resistance of the cured resin layer (A) is high. For example, when a manufacturing process involving heating is performed after the formation of the cured resin layer (A), such as forming a functional layer on the cured resin layer (A) by coating and heat drying as described above, thermal shrinkage is suppressed, making it less likely for mechanical deformation (e.g., warping, peeling, wrinkling, etc.) to occur in the functional layer, and allowing the functional layer to fully exhibit its intended function. The thermal shrinkage rate can be evaluated, for example, by the following method. A 40 μm thick cured resin layer (A) was cut into 5 mm × 30 mm test pieces. Using a thermomechanical analyzer (NETZSCH Japan, model "TMA4000SE"), the cured resin layer (A) was gripped with the chuck distance set to 20 mm. The sample was then heated from 25 °C to 100 °C at a heating rate of 5 °C / min and held for 2 minutes. After that, it was cooled to 25 °C at a cooling rate of 5 °C / min. The rate of change in displacement in the longitudinal direction (the value expressed as a percentage of the displacement relative to the 20 mm chuck distance) was defined as the thermal change rate. A negative value indicates that the cured resin layer (A) has shrunk (thermal shrinkage), while a positive value indicates that the cured resin layer (A) has stretched.

[0090] The elongation at break of the cured resin layer (A) is preferably 2.5% or more, more preferably 3.0% or more, and even more preferably 3.5% or more. When the elongation at break of the cured resin layer (A) is within this range, for example, if it is 2.5% or more, it becomes easier to adjust the elongation at break of the laminate including the functional layer to about 2% or more, and as a result, it becomes easier to obtain a laminate with excellent flexibility. Furthermore, the elongation at break can be evaluated using, for example, the following method. A cured resin layer (A) with a thickness of 5 μm was cut into 15 mm x 150 mm test specimens, and the elongation at break was measured according to JIS K7127:1999. Specifically, the above test specimens were subjected to a tensile test on a tensile testing machine (Shimadzu Corporation, Autograph) with the chuck distance set to 100 mm, at a speed of 200 mm / min, and the elongation at break (%) was measured. If the test specimen did not have a yield point, the tensile strain at break was used as the elongation at break; if it had a yield point, the strain at the yield point was used as the elongation at break.

[0091] The in-plane phase difference of the curable resin layer (A) is preferably 2.0 nm or less, more preferably 1.5 nm or less, even more preferably 1.0 nm or less, even more preferably 0.5 nm or less, and particularly preferably 0.3 nm or less. The in-plane phase difference was calculated using the following formula (1). Re(λ)=(nx-ny)×d (1) Here, Re(λ) is the in-plane phase difference of the cured resin layer measured with light of wavelength λnm at 23°C. For example, "Re(450)" is the in-plane phase difference of the cured resin layer measured with light of wavelength 450nm at 23°C. Also, "nx" is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow phase axis direction), "ny" is the refractive index in the direction perpendicular to the slow phase axis in the plane (i.e., the fast phase axis direction), and d is the thickness of the cured resin layer (nm). In contrast, the phase difference in the thickness direction is usually -500 nm or less, and preferably -450 nm or less. Furthermore, the value obtained by dividing the in-plane phase difference by the thickness of the cured resin layer (birefringence) is usually 100 × 10⁻⁶. -5 The following are preferred, preferably 20 × 10 -5 The following applies: If the in-plane phase difference, thickness-direction phase difference, and birefringence of the cured resin layer (A) are within the above range, it exhibits excellent optical isotropy and can therefore be preferably used as a component for optical applications. The in-plane phase difference was measured using the method described in the examples below.

[0092] The thickness of the cured resin layer (A) is not particularly limited and can be appropriately adjusted according to the purpose of the laminate having a functional layer, for example. The thickness of the cured resin layer (A) is usually 50 μm or less, preferably 20 μm or less, more preferably 0.1 to 20 μm, even more preferably 0.1 to 15 μm, and particularly preferably 0.2 to 10 μm. When the thickness of the cured resin layer (A) is within this range, even when a functional layer is included in the laminate, it is possible to prevent the thickness of the laminate from increasing, resulting in a thin laminate. A thin laminate is preferable in applications such as devices where further thinning is required, as the laminate does not contribute to increasing the overall thickness of the device. Furthermore, the amount of stretching strain of the outermost layer when the laminate is bent can be reduced, improving the flexibility of the laminate. In addition, a thin laminate ensures flexibility after mounting the laminate.

[0093] The cured resin layer (A) used in the present invention has excellent solvent resistance. Due to its excellent solvent resistance, even when an organic solvent is used to form another layer on the surface of the cured resin layer (A), the surface of the cured resin layer (A) hardly dissolves. Therefore, even when a functional layer is formed on the surface of the cured resin layer (A) using a resin solution containing an organic solvent, the components of the cured resin layer (A) do not easily penetrate into the functional layer, so the original function of the functional layer is not easily degraded. From the above viewpoint, the gel fraction of the cured resin layer (A) is preferably 80% or more, more preferably 85% or more, even more preferably 87% or more, and particularly preferably 90% or more. Since a cured resin layer (A) with a gel fraction of 80% or more has excellent solvent resistance, even when an organic solvent is used to form a functional layer on the surface of the cured resin layer (A) by coating, the surface of the cured resin layer (A) hardly dissolves, making it easy to obtain a laminate with excellent solvent resistance. Here, the gel fraction was calculated, for example, by performing the following operations (a), (b), and (c), and dividing the weight of the dried component measured by the weight of the component before immersion in MEK (methyl ethyl ketone) solvent. (a) The cured resin layer (A) is wrapped in mesh (NBC Mesh Tech, α_UX SCREEN 150-035 / 380TW) and secured with staples, and the weight of the resulting structure is measured. (b) Immerse the components in a bottle filled with methyl ethyl ketone (MEK) solvent, seal it, and leave it at 25°C for 36 hours. (c) Remove the components from the solvent, dry them at 100°C for 60 minutes, and measure the weight of the components after drying.

[0094] <Resin layer> The laminate of the present invention includes a resin layer. The resin layer is used as a process film 1 for forming a cured resin layer (A).

[0095] Process film 1 is preferably in the form of a sheet or film. The term "sheet or film" is not limited to long lengths, but also includes short, flat pieces. The process film 1 is not particularly limited, but is preferably a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, or a plastic film such as a polyolefin film such as polyethylene or polypropylene. Furthermore, for ease of handling, process film 1 may have a release layer provided on the plastic film. The release layer can be formed by known methods using conventionally known release agents such as silicone-based release agents, fluorine-based release agents, alkyd-based release agents, and olefin-based release agents. The thickness of the release layer is not particularly limited, but is usually 0.02 to 2.00 μm, more preferably 0.05 to 1.50 μm. The thickness of process film 1 is preferably 1 to 500 μm, and more preferably 5 to 300 μm, from the standpoint of ease of handling.

[0096] The average surface roughness (arithmetic mean roughness Ra) of the surface of process film 1 facing the cured resin layer (A) is preferably 0.5 nm to 10.0 nm, and more preferably 0.8 nm to 5.0 nm. The maximum surface roughness (maximum cross-sectional height Rt) is preferably 10 nm to 800 nm, and more preferably 20 nm to 500 nm. When the arithmetic mean roughness Ra and the maximum cross-sectional height Rt are within this range, it becomes easier to separate the hardened resin layer (A) from the heat treatment before and after the heat treatment. The arithmetic mean roughness Ra and maximum cross-sectional height Rt were determined by the methods described in the examples below. Furthermore, process film 1 is usually peeled off in a predetermined process depending on the intended use of the laminate.

[0097] <Cured resin layer (B)> The laminate of the present invention includes a cured resin layer (B). The cured resin layer (B) is a layer made of a cured product of curable resin composition 2 containing polymer component (N) and / or curable monomer (Q). The curable resin layer (B) may be a single layer or multiple layers. The cured resin layer (B) has the function of suppressing the precipitation of oligomer components in the resin layer and is used as process film 2. The method for forming the cured resin layer (B) will be described in detail later in the section on the manufacturing method of the laminate.

[0098] (Polymer component (N)) The cured resin layer (B) may contain a polymer component (N). Examples of polymer components (N) include thermoplastic resins. As thermoplastic resins, from the viewpoint of heat resistance, thermoplastic resins having a ring structure such as an aromatic ring structure or an alicyclic structure are preferred, and thermoplastic resins having an aromatic ring structure are more preferred. Examples of such thermoplastic resins include polyimide resins, polysulfone resins, polyarylate resins, polycarbonate resins, and alicyclic hydrocarbon resins.

[0099] As the polyimide resin, the same one used as the polymer component (M) described above can be used. Similarly, the same polyarylate resin used as the polymer component (M) described above can be used. Polysulfone resins are polymers having sulfone groups (-SO2-) in their main chain, and are not particularly limited; known types can be used.

[0100] Examples of polysulfone resins include polyethersulfone resins, polysulfone resins, and polyphenylsulfone resins. Furthermore, the polysulfone resin used in the present invention may be a modified polysulfone resin. Specifically, polysulfone resins include resins composed of polymer compounds having repeating units represented by (a) to (h) below. [ka]

[0101] [ka] As the polysulfone resin, polyethersulfone resin or polysulfone resin is preferred.

[0102] Polycarbonate resins are polymers having carbonate groups (-OC(=O)-O-) in their main chain. There are no particular limitations on the polycarbonate resin used; known types can be used. Examples of polycarbonate resins include aromatic polycarbonate resins and aliphatic polycarbonate resins. Among these, aromatic polycarbonate resins are preferred due to their excellent heat resistance, mechanical strength, and transparency. Aromatic polycarbonate resins can be obtained by reacting aromatic diols with carbonate precursors using interfacial polycondensation or molten transesterification, by polymerizing carbonate prepolymers using solid-phase transesterification, or by polymerizing cyclic carbonate compounds using ring-opening polymerization. Examples of aromatic diols include those found in the polyarylate resin of polymer component (M). Examples of carbonate precursors include carbonyl halides, carbonate esters, or haloformates, specifically phosgene, diphenyl carbonate, or dihydric phenol dihaloformates.

[0103] Alicyclic hydrocarbon resins are polymers having cyclic hydrocarbon groups in their main chain. Alicyclic hydrocarbon resins are not particularly limited, and known ones can be used. Examples of alicyclic hydrocarbon resins include monocyclic olefin polymers, norbornene polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and their hydrides. Specific examples include Apel (ethylene-cycloolefin copolymer manufactured by Mitsui Chemicals), Arton (norbornene polymer manufactured by JSR), and Zeonor (norbornene polymer manufactured by Nippon Zeon Corporation). Thermoplastic resins can be used individually or in combination of two or more types.

[0104] Among the resins used as the polymer component (N) mentioned above, polyimide resins are particularly preferred because they have a high Tg and excellent heat resistance, and are easily obtainable that are soluble in general-purpose organic solvents while exhibiting good heat resistance.

[0105] (Curing monomer (Q)) The curable monomer (Q) is a monomer having polymerizable unsaturated bonds and is capable of participating in polymerization reactions, or polymerization reactions and crosslinking reactions. The curable monomer (Q) can be the same as the curable monomer (P) described above, and there are no particular restrictions on the number of polymerizable unsaturated bonds in the curable monomer (Q). Furthermore, the curable monomer (Q) may be a monofunctional monomer having one polymerizable unsaturated bond, or a polyfunctional monomer such as a 2- to 6-functional monomer having multiple polymerizable unsaturated bonds. The curable monomer (Q) can be used alone or in combination of two or more types.

[0106] (Filler component) The cured resin layer (B) preferably further contains a filler component. The inclusion of a filler component improves heat resistance and makes it easier to suppress the precipitation of oligomer components from adjacent resin layers. The filler components are not particularly limited, but examples include silicon oxide, titanium oxide, alumina (Al2O3), and zirconia (ZrO2). The silicon oxide is preferably a particulate silicon oxide. For example, silicon dioxide (silica) particles can be used. The average particle size of the silicon oxide used in the present invention is not particularly limited, but is usually 0.10 to 3 μm. Furthermore, the silicon oxide may be obtained by any manufacturing method, and its surface may be surface-treated with a surface treatment agent such as a silane coupling agent, and the surface treatment may be a silane coupling agent having an acryloyl group. The average particle size of the filler component can be determined, for example, by measuring the particle size distribution using a laser diffraction particle size analyzer (Malvern Mastersizer 3000).

[0107] <Curable resin composition 2> The curable resin composition 2 used in the present invention can be prepared by mixing the aforementioned polymer component (N) and / or curable monomer (Q), and preferably a filler component, and optionally a polymerization initiator and other components used for the aforementioned curable monomer (P), and dissolving or dispersing them in a suitable solvent.

[0108] When a polymer component (N) and a curable monomer (Q) are used in combination, the total content of the polymer component (N) and the curable monomer (Q) in the curable resin composition 2 is preferably 40 to 99.5% by mass, more preferably 60 to 99% by mass, and even more preferably 80 to 98% by mass, based on the total mass of the curable resin composition 2 excluding the solvent. Furthermore, the content of polymer component (N) and curable monomer (Q) in the curable resin composition 2 is preferably such that the mass ratio of polymer component (N) to curable monomer (Q) is 20:80 to 90:10, and more preferably 30:70 to 70:30. Furthermore, the content of thermoplastic resin in the polymer component (N) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total mass of the polymer component (N) excluding the solvent. The filler component content is preferably 30 to 70% by mass, more preferably 45 to 65% by mass, based on the total mass excluding the solvent. When the filler component content is within this range, the heat resistance of the cured resin layer (B) is further improved, and the precipitation of oligomer components from the resin layer is more easily suppressed.

[0109] The solvent and solvent content used in preparing the curable resin composition 2 are the same as those used in preparing the curable resin composition 1 described above.

[0110] Furthermore, the curable resin composition 2 may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, to the extent that they do not impair the objectives and effects of the present invention.

[0111] Examples of commercially available curable resin compositions 2 include "Opstar Z7530", "Opstar Z7524", "Opstar Z7537", and "Opstar TU4086" from Arakawa Chemical Industries, Ltd.

[0112] The thickness of the cured resin layer (B) can be adjusted as appropriate, taking into consideration, for example, adhesion to the resin layer, mechanical strength, etc. The thickness of the cured resin layer (B) is usually 50 μm or less, preferably 20 μm or less, more preferably 0.1 to 20 μm, even more preferably 0.3 to 10 μm, and particularly preferably 0.5 to 5 μm.

[0113] (Method of manufacturing a laminate) The present invention provides a method for manufacturing a laminate, comprising the following steps (1) to (5). (Step 1): A step of forming a cured resin layer (A) (coating film) on one side of the resin layer using a curable resin composition 1 containing a polymer component (M) and a curable monomer (P). (Step 2): A step to cure the cured resin layer (A) (coating film) obtained in Step 1 to form a cured resin layer (A). (Step 3): A step to form a cured resin layer (B) (coating film) on the other side of the resin layer using a curable resin composition 2 containing polymer component (N) and / or curable monomer (Q). (Step 4): A step to cure the cured resin layer (B) (coating film) obtained in Step 3 to form a cured resin layer (B). (Step 5): A step to form a functional layer on the cured resin layer (A) of the laminate obtained in Step 4.

[0114] In step 1, the method for coating the curable resin composition 1 onto the step film 1 is not particularly limited, and known coating methods such as spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating can be used.

[0115] The method for drying the resulting coating film is not particularly limited, and conventionally known drying methods such as hot air drying, hot roll drying, and infrared irradiation can be used. The drying temperature of the coating film is typically 30 to 150°C, preferably 50 to 130°C.

[0116] In step 2, the method for curing the cured resin layer (A) (coating film) is not particularly limited, and known methods can be used. For example, if the cured resin layer (A) (coating film) is formed using a curable resin composition 1 containing a thermal polymerization initiator, the cured resin layer (A) (coating film) can be cured by heating it. The heating temperature is usually 30 to 150°C, preferably 50 to 130°C. Furthermore, if the cured resin layer (A) (coating film) is formed using a curable resin composition 1 containing a photopolymerization initiator, the cured resin layer (A) (coating film) can be cured by irradiating it with active energy rays. The active energy rays can be irradiated using a high-pressure mercury lamp, an electrodeless lamp, a xenon lamp, etc.

[0117] The wavelength of the active energy rays is preferably 200-400 nm, and more preferably 350-400 nm. The illuminance of the active energy rays is typically 50-1,000 mW / cm². 2 Preferably 70-300 mW / cm² 2 This range is 50-5,000 mJ / cm². 2 Preferably 300-4,000 mJ / cm² 2 The range is as follows. The irradiation time is usually 0.1 to 1,000 seconds, preferably 1 to 500 seconds, and more preferably 10 to 100 seconds. Multiple irradiations may be performed to satisfy the above-mentioned light intensity, taking into account the thermal load of the light irradiation process.

[0118] In this case, in order to prevent degradation of the polymer component (M) and discoloration of the cured resin layer (A) due to irradiation with active energy rays, the curable resin composition 1 may be irradiated with active energy rays via a filter that absorbs light of wavelengths unnecessary for the curing reaction. With this method, since light of wavelengths unnecessary for the curing reaction and that degrades the polymer component (M) is absorbed by the filter, the degradation of the polymer component (M) is suppressed, and a colorless and transparent cured resin layer (A) is more easily obtained. As a filter, a resin film such as polyethylene terephthalate film can be used. When using a resin film, it is preferable to include a step between step 1 and step 2 in which a resin film such as polyethylene terephthalate film is laminated onto the cured resin layer (A) (coating). The resin film is usually peeled off after step 2.

[0119] Furthermore, the cured resin layer (A) (coating film) can also be cured by irradiating it with an electron beam. When irradiating with an electron beam, the cured resin layer (A) (coating film) can usually be cured without using a photopolymerization initiator. When irradiating with an electron beam, an electron beam accelerator or the like can be used. The irradiation dose is usually in the range of 10 to 1,000 krad. The irradiation time is usually 0.1 to 1,000 seconds, preferably 1 to 500 seconds, and more preferably 10 to 100 seconds.

[0120] The cured resin layer (coating) (A) may be cured under an inert gas atmosphere such as nitrogen gas, if necessary. Curing under an inert gas atmosphere makes it easier to avoid oxygen, moisture, etc., from interfering with the curing process.

[0121] In step 3, the method for coating the curable resin composition 2 onto the process film 2 and the method for drying the obtained curable resin layer (B) (coating film) can be carried out in the same manner as described in step 1 above. Furthermore, in (Step 4), the method for curing the cured resin layer (B) (coating film) can be the same as in (Step 2) described above. Note that if only polymerizable component (N) is used to coat the film in (Step 3), this step is unnecessary.

[0122] In step (5), the method for forming the desired functional layer on the cured resin layer (A) obtained in step (2) can be the method described above, depending on the functional layer to be used.

[0123] Thus, the manufacturing method including steps (1) to (5) above uses process film 1 and process film 2 to form a cured resin layer (A), or a cured resin layer (A) and a functional layer.

[0124] According to the above-described method for manufacturing the laminate, a laminate according to one aspect of the present invention can be manufactured efficiently, continuously, and easily. [Examples]

[0125] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited in any way by these examples.

[0126] The haze value, peel strength, and surface roughness of the laminates prepared in the examples and comparative examples were evaluated by the following method.

[0127] (1) Haze value The laminates prepared in the examples and comparative examples were cut into 50 mm x 50 mm test specimens, and the haze value (%) of each specimen was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") in accordance with JIS K7136:2000. Furthermore, the test specimens were subjected to heat treatment (150°C, 1 hour) using an oven (manufactured by ESPEC, model name "SPHH202"), and the haze value (%) was measured in the same manner. (2) Peeling force The laminates prepared in the examples and comparative examples were cut to a width of 50 mm and a length of 150 mm. The side of the laminate with the curable resin layer (A) was fixed to an aluminum plate (width 50 mm, length 150 mm, thickness 1 mm) with double-sided adhesive film to prepare a test specimen. Next, at 23°C and 50% RH, the curable resin layer (A) and the resin layer of the test specimen were peeled using a high-speed peel tensile testing machine (manufactured by Tester Sangyo Co., Ltd., product name "High-Speed ​​Peel Testing Machine TE-701") under conditions of a peel angle of 180° and a peel speed of 20 m / min, and the peel force (mN / 50 mm) at that time was measured. Furthermore, separately prepared test specimens were heat-treated (150°C, 1 hour) using an oven (ESPEC Corporation, model "SPHH202"), and the peeling force was measured using the same method. The peeling force was calculated as the average of two measurements in accordance with JIS Z0237:2000. (3) Surface roughness The surface roughness of the side of process film 1 (resin layer) where the cured resin layer (A) is formed, specifically the average surface roughness (arithmetic mean roughness Ra) and the maximum surface roughness (maximum cross-sectional height Rt), was measured in a 100 μm × 100 μm measurement area using an optical interferometry surface shape analyzer (Veeco Metrology Group, product name "WYKO WT1100") in PSI mode (Phase Shift Interferometry) at a magnification of 50x.

[0128] (Example 1) • Fabrication of laminates Curable resin compositions 1 and 2 were prepared as follows. As the polymer component (M), 100 parts by mass of polyimide resin pellets (manufactured by Kawamura Sangyo Co., Ltd., product name "KPI-MX300F", Tg=354℃, weight-average molecular weight 190,000) were dissolved in methyl ethyl ketone (MEK) to prepare a 15% by mass solution of polyimide resin. Next, 122 parts by mass of tricyclodecanedimethanol diacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd., A-DCP, molecular weight 304.4) as the curable monomer (P) and 5 parts by mass of (2,4,6-trimethylbenzoyl)-phenylphosphine oxide (manufactured by BASF, IrgacureTPO) as the polymerization initiator were added to this solution and mixed to prepare curable resin composition 1. Note that the curable monomer (A) and polymerization initiator do not contain solvents and are all raw materials with 100% solid content. Furthermore, as a curable resin layer (B), a curable resin composition 2 containing a curable monomer (Q) and silica particles was prepared [Arakawa Chemical Industries, Ltd., product name "Opstar Z7530", a mixture of a substance formed by bonding acryloyl groups to silica particles, polyfunctional acrylate monomers and oligomers, a photopolymerization initiator, a solvent, and other additives: an energy ray curable compound containing 43% by mass of silica fine particles and 28% by mass of polyfunctional acrylate monomers and oligomers, 2% by mass of a photopolymerization initiator, 23% by mass of methyl ethyl ketone, and 4% by mass of other additives]. Next, as the process film 1 (resin layer), a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "Cosmoshine A4100", thickness 50 μm) having an easy-adhesion layer on one side was used. The curable resin composition 1 was applied to the side of this PET film opposite to the easy-adhesion layer side, and the resulting coating was heated at 100°C for 2 minutes to dry. Subsequently, using a high-pressure mercury lamp (manufactured by iGraphix, product name "H04-L41"), an illuminance of 130 mW / cm² was achieved at a light wavelength of 365 nm. 2 , Light intensity 700 mJ / cm 2 Under the conditions of a Heraus UV Power Puck(II) II ultraviolet light meter, a curing reaction was carried out by ultraviolet irradiation in a nitrogen atmosphere to form a cured resin layer (A) with a thickness of 5 μm. Furthermore, the curable resin composition 2 was applied to the easily adhering layer surface of the PET film, and the resulting coating was heated at 100°C for 2 minutes to dry. Subsequently, using a conveyor-type ultraviolet irradiation device (Heraus Corporation, device name "CV-100Q-G"), an irradiance of 250 mW / cm² at a light wavelength of 365 nm was achieved. 2 The light intensity is 170 mJ / cm². 2 A laminate was fabricated by curing the resin by irradiating it with ultraviolet light under the conditions of a Heraus UV Power Puck(registered trademark) II ultraviolet light meter, forming a 1 μm thick curable resin layer (B) as process film 2. The haze value of the obtained laminate, the peeling force between the cured resin layer (A) and the resin layer, and the surface roughness [average surface roughness (arithmetic mean roughness Ra) and maximum surface roughness (maximum cross-sectional height Rt)] of the side of the process film 1 used opposite the easy-adhesion layer were evaluated. The results are shown in Table 1.

[0129] (Example 2) A laminate was prepared in the same manner as in Example 1, except that another polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., product name "Lumirror T60", thickness 50 μm) was used as process film 1. The haze value of the obtained laminate, the peeling force between the cured resin layer (A) and the resin layer, and the surface roughness [average surface roughness (arithmetic mean roughness Ra) and maximum surface roughness (maximum cross-sectional height Rt)] of the side of the process film 1 used opposite the easy-adhesion layer were evaluated. The results are shown in Table 1.

[0130] (Comparative Example 1) A laminate (consisting of two layers: a curable resin layer (A) and a resin layer) was prepared in the same manner as in Example 1, except that a curable resin layer (B) was not formed using curable resin composition 2. The haze value of the obtained laminate, the peeling force between the cured resin layer (A) and the resin layer, and the surface roughness [average surface roughness (arithmetic mean roughness Ra) and maximum surface roughness (maximum cross-sectional height Rt)] of the side of the process film 1 used opposite the easy-adhesion layer were evaluated. The results are shown in Table 1.

[0131] The chemical structural formulas of the curable monomer (P) used in the examples and comparative examples are shown below.

[0132] [ka]

[0133] [Table 1]

[0134] The laminates of Examples 1 and 2, which have a cured resin layer (B) on the side of the resin layer opposite to the cured resin layer (A), showed suppressed precipitation of oligomer components in the resin layer after heating at 150°C for 1 hour, compared to the laminate of Comparative Example 1, which does not have a cured resin layer (B) on the opposite side. This resulted in a lower haze value, and the peel force between the resin layer and the cured resin layer (A) was maintained within a range of peelable peel force, independent of the surface roughness of the resin layer used. [Industrial applicability]

[0135] According to the laminate of the present invention, the precipitation of oligomer components derived from the resin layer at high temperatures is suppressed and the haze value is maintained. Therefore, it is expected to be applied to substrates for components of electronic devices such as display devices that require heat treatment in the manufacturing process, or components and substrates of optical films, such as components and substrates for transparent conductive layers such as ITO used in flexible organic EL displays, liquid crystal displays, touch panels, etc., as well as anti-reflective hard coat films and polarizing plate protective films for polarizing plates. [Explanation of Symbols]

[0136] 1,11: Laminate 2: Cured resin layer (A) 3: Resin layer 4: Cured resin layer (B) 5: Functional Layer

Claims

1. A laminate comprising a cured resin layer (A), a resin layer, and a cured resin layer (B) in this order, wherein the cured resin layer (A) is a layer made of a cured product of a curable resin composition 1 containing a polymer component (M) including a polyimide resin and a curable monomer (P), and the cured resin layer (B) is a layer made of a cured product of a curable resin composition 2 containing a curable monomer (Q) and a filler component. The resin layer is a polyester film or polyolefin film containing an oligomer component. The curable monomer (P) is a monofunctional monomer having one polymerizable unsaturated bond, or a polyfunctional monomer having multiple polymerizable unsaturated bonds. The curable monomer (Q) is a monofunctional monomer having one polymerizable unsaturated bond, or a polyfunctional monomer having multiple polymerizable unsaturated bonds. The content of the polymer component (M) and the curable monomer (P) in the curable resin composition 1 is such that the mass ratio of the polymer component (M) to the curable monomer (P) is polymer component (M):curable monomer (P) = 20:80 to 90:

10. The content of the curable monomer (Q) and the filler component in the curable resin composition 2 is such that the mass ratio of the curable monomer (Q) to the filler component is 30:70 to 70:

30. Laminated structure.

2. The laminate according to claim 1, wherein the filler component is silicon oxide, titanium oxide, alumina (Al₂O₃), or zirconia (ZrO₂).

3. The polymer component (M) has a weight-average molecular weight of 100,000 or more, as described in claim 1. A laminate of [something].

4. The laminate according to any one of claims 1 to 3, wherein the glass transition temperature of the polymer component (M) is 250°C or higher.

5. The laminate according to any one of claims 1 to 3, wherein the thickness of the cured resin layer (A) is 20 μm or less.

6. The laminate according to any one of claims 1 to 3, wherein the haze value of the laminate is 2.0% or less.

7. The laminate according to any one of claims 1 to 3, wherein the haze value of the laminate after heating at 150°C for 1 hour is 2.0% or less.

8. The laminate according to any one of claims 1 to 3, wherein the peel force between the cured resin layer (A) and the resin layer after heating at 150°C for 1 hour is 500 mN / 50 mm or less and 30 mN / 50 mm or more.

9. The laminate according to any one of claims 1 to 3, further comprising a release layer between the cured resin layer (A) and the resin layer, wherein the peeling force between the cured resin layer (A) and the release layer after heating at 150°C for 1 hour is 500 mN / 50 mm or less and 30 mN / 50 mm or more.

10. The laminate according to any one of claims 1 to 3, further comprising a functional layer on one or both surfaces of the cured resin layer (A).

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