Optical films, manufacturing methods of optical films, transparent conductive films, and gas barrier films.

Abstract

This invention provides an optical film that is thin, has excellent heat resistance, and is easy to form with functional layers such as transparent conductive layers and gas barrier layers. The optical film comprises a process film and a curable resin layer, wherein the curable resin layer is a layer formed by curing a curable resin composition, the curable resin composition containing a polymer component (A) and a curable monomer (B), [a] the characteristic values ​​obtained from the dynamic viscoelasticity measurement of the optical film at a heating rate of 3°C / second from 25°C to 280°C, (I) in the curve representing the change of loss tangent with temperature, there is more than one loss tangent peak, and the peak temperature of all loss tangent peaks is 150°C or higher, (II) the storage modulus reduction rate is 40% or less, the storage modulus reduction rate being the rate of reduction of storage modulus from 25°C to 150°C; or, [b] the glass transition temperature of the polymer component (A) is 250°C or higher, and in the above curve, there is more than one loss tangent peak, and the peak temperature of all loss tangent peaks is 150°C or higher.

Description

Technical Field

[0001] This invention relates to optical films, methods for manufacturing optical films, transparent conductive films, and gas barrier films. Background Technology

[0002] Transparent conductive films are used in liquid crystal displays, EL (electroluminescent) displays, EC (electrochromic) displays, solar cells, electromagnetic shielding films for electromagnetic shielding, and membrane sensors for transparent touch panels. These transparent conductive films are obtained by forming a transparent conductive layer on the surface of a substrate film.

[0003] In the manufacturing process of transparent conductive films, most processes involve sputtering of metal compounds and subsequent annealing under harsh conditions accompanied by heating. Therefore, optical films, which serve as substrates for forming transparent conductive layers, require high heat resistance. It is believed that this problem is solved by using heat-resistant optical films formed from highly heat-resistant resins such as polyimide resins (e.g., resins with a glass transition temperature of 250°C or higher).

[0004] In addition, gas barrier films are widely used as substrate materials and sealing materials. Gas barrier films require high gas barrier properties to suppress the permeation of water vapor, oxygen, and other substances. Furthermore, for example, to avoid compromising the visibility of the objects to which the gas barrier film is attached, it is necessary to improve light transmittance, and it is also necessary to design the film to be lightweight without compromising the object being attached.

[0005] From the above perspective, the following technique is known: A curable composition containing a curable compound is coated onto a support, and the curable compound contained in the resulting coating layer is cured to form a thin cured resin layer, thereby producing an optical film. Then, a gas barrier layer formed of an inorganic film or the like is formed directly on or through other layers on the cured resin layer of this optical film. Hereinafter, the property of inhibiting the permeation of water vapor and oxygen is referred to as "gas barrier property," a layer with gas barrier property is referred to as a gas barrier layer, and a film with a gas barrier layer is referred to as a "gas barrier film."

[0006] For example, Patent Document 1 describes forming a cured resin layer on a process sheet using a cured resin composition comprising a resin such as a polysulfone resin and a curable monomer, and forming a gas barrier layer on the cured resin layer. This manufacturing method yields a gas barrier film with the cured resin layer on one surface and the gas barrier layer on the other.

[0007] In recent years, there has been a demand for further thinning of optical films in order to improve the transparency and flexibility of transparent conductive films and gas barrier films, as well as to make them lighter.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: International Publication No. 2013 / 065812 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Previous optical films with curable resin layers had the following problems.

[0013] First, it must be solvent-resistant so that it will not be damaged by solvents when coating the cured resin layer with liquids such as polysilazane-based gas barrier layers or dispersions of silver nanowires used for transparent conductive layers. Furthermore, it must be able to withstand thermal loads when preventing a significant decrease in the storage modulus or an increase in the coefficient of linear expansion of the optical film when exposed to high temperatures, thus preventing the formation of transparent conductive layers or gas barrier layers.

[0014] The requirements for these properties are increasing as the need to further thin optical films for transparency and lightweighting becomes more urgent, necessitating further improvements.

[0015] In view of the above problems, the objective of this invention is to provide an optical film that is thin, has excellent heat resistance, and is easy to form with functional layers such as transparent conductive layers and gas barrier layers, and a method for manufacturing the same. Another objective of this invention is to provide a transparent conductive film and a gas barrier film that are easy to manufacture, thin, and have excellent heat resistance.

[0016] Problem Solving Methods

[0017] The inventors, through repeated and in-depth research to solve the above-mentioned problems, discovered that in an optical film comprising a process film and a cured resin layer, the cured resin layer is formed from a cured product of a curable resin composition, and the peak temperature of all loss tangent peaks in the measurement curve obtained by dynamic viscoelasticity measurement of the cured resin layer is above a given temperature, thereby possessing the given physical properties. This solves the above-mentioned problems, and thus the present invention is completed.

[0018] That is, the present invention provides the following [1] to [6].

[0019] [1] An optical film comprising a process film and a cured resin layer, the cured resin layer being a layer formed from a cured product of a curable resin composition, the curable resin composition containing a polymer component (A) and a curable monomer (B), wherein the characteristic values ​​of the optical film obtained in a dynamic viscoelasticity test by heating from 25°C to 280°C at a heating rate of 3°C / second satisfy the following (I) and (II).

[0020] (I) In the curve representing the change of loss tangent relative to temperature, there is more than one loss tangent peak, and the peak temperature of all loss tangent peaks is above 150℃.

[0021] (II) The energy storage modulus reduction rate calculated by the following formula (1) is less than 40%, which is the reduction rate of the energy storage modulus from 25°C to 150°C.

[0022] Energy storage modulus reduction rate = (energy storage modulus at 25℃ - energy storage modulus at 150℃) ÷ energy storage modulus at 25℃ × 100 (%) ··· Equation (1).

[0023] [2] An optical film comprising a process film and a curable resin layer, the curable resin layer being a layer formed from a cured product of a curable resin composition, the curable resin composition containing a polymer component (A) and a curable monomer (B), the polymer component (A) having a glass transition temperature of 250°C or higher, and in a dynamic viscoelasticity test of the optical film obtained by heating from 25°C to 280°C at a heating rate of 3°C / second, a curve representing the change of loss tangent relative to temperature exists, and the peak temperature of all loss tangent peaks is 150°C or higher.

[0024] [3] The optical film described in [1] or [2] above, wherein the thickness of the cured resin layer is less than 20 μm.

[0025] [4] A method for manufacturing an optical film, the method comprising:

[0026] In the first step, a curable resin layer is formed on the process film. The curable resin layer is formed from a curable resin composition containing a polymer component (A) and a curable monomer (B).

[0027] The second step involves irradiating the curable resin layer with at least one of an energy beam and an electron beam, thereby curing at least a portion of the curable resin layer; and

[0028] The third step involves heating the curable resin layer to above 150°C after the second step begins, thereby obtaining the cured resin layer.

[0029] [5] A transparent conductive film comprising: an optical film as described in any one of [1] to [3] above, and a transparent conductive layer disposed on the cured resin layer of the optical film.

[0030] [6] An air barrier film comprising: an optical film as described in any one of [1] to [3] above, and an air barrier layer disposed on the cured resin layer of the optical film.

[0031] The effects of the invention

[0032] According to the present invention, a thin, heat-resistant optical film with easily formed functional layers such as transparent conductive layers and gas barrier layers can be provided, as well as a method for manufacturing the same. Furthermore, according to the present invention, a thin, easily manufactured transparent conductive film and a gas barrier film with excellent heat resistance can be provided. Attached Figure Description

[0033] Figure 1 This is a cross-sectional schematic diagram showing an example of the structure of an optical film according to an embodiment of the present invention.

[0034] Figure 2 This is a cross-sectional schematic diagram showing an example of the structure of the transparent conductive film and the gas barrier film according to an embodiment of the present invention.

[0035] Figure 3 This is a process diagram illustrating an example of a method for manufacturing an optical film.

[0036] Symbol Explanation

[0037] 1, 1A, 1B: Process membranes

[0038] 2: Cured resin layer

[0039] 2a: Curing resin layer

[0040] 2b: Cured resin layer after irradiation with energy rays or electron beams

[0041] 3: Transparent conductive layer

[0042] 4: Gas barrier layer

[0043] 10A, 10B: Optical films

[0044] 20: Transparent conductive film

[0045] 21: The transparent conductive layer is a patterned transparent conductive film.

[0046] 22: Gas barrier membrane

[0047] 31: A patterned transparent conductive layer Detailed Implementation

[0048] In this specification, “XX~YY” means “XX and above and YY and below”.

[0049] In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and so on for other similar terms.

[0050] Hereinafter, various optical films involved in the embodiments of the present invention will be described.

[0051] 1. Optical films

[0052] An optical film according to one embodiment of the present invention comprises a process film and a cured resin layer, wherein the cured resin layer is a layer formed by curing a cured resin composition, the cured resin composition containing a polymer component (A) and a cured monomer (B), and the characteristic values ​​obtained by the optical film in a dynamic viscoelasticity test by heating from 25°C to 280°C at a heating rate of 3°C / second satisfy the following (I) and (II).

[0053] (I) In the curve representing the change of loss tangent relative to temperature, there is more than one loss tangent peak, and the peak temperature of all loss tangent peaks is above 150℃.

[0054] (II) The energy storage modulus reduction rate calculated by the following formula (1) is less than 40%, which is the reduction rate of the energy storage modulus from 25°C to 150°C.

[0055] Energy storage modulus reduction rate = (energy storage modulus at 25℃ - energy storage modulus at 150℃) ÷ energy storage modulus at 25℃ × 100 (%) ··· Equation (1).

[0056] The inventors have discovered the following issues as a result of their in-depth research.

[0057] (i) By making the cured resin layer a layer formed from a cured resin composition containing a polymer component (A) and a curable monomer (B), effects such as improved solvent resistance and peelability from the process film can be obtained.

[0058] (ii) In addition, regarding the characteristic values ​​obtained from the dynamic viscoelasticity measurement of heating from 25°C to 280°C at a heating rate of 3°C / second, (I) if there is more than one loss tangent peak in the curve representing the change of loss tangent relative to temperature, and the peak temperature of all loss tangent peaks is 150°C or higher, then the change in storage modulus and coefficient of linear expansion of the cured resin layer at high temperature can be reduced; moreover, (II) if the storage modulus reduction rate calculated by the above formula (1) is 40% or less, then it can withstand the heat load when forming functional layers such as transparent conductive layers and gas barrier layers, where the above storage modulus reduction rate is the reduction rate of storage modulus from 25°C to 150°C.

[0059] (iii) Furthermore, by including curable monomers in the curable resin composition, curling can be suppressed after the process film is peeled off, and the peeling of the process film becomes easier.

[0060] Another embodiment of the present invention relates to an optical film comprising a process film and a cured resin layer, wherein the cured resin layer is a layer formed by curing a curable resin composition, the curable resin composition comprising a polymer component (A) and a curable monomer (B), the glass transition temperature of the polymer component (A) being 250°C or higher, and in the curve representing the change of loss tangent with temperature obtained in the dynamic viscoelasticity measurement of the optical film by heating from 25°C to 280°C at a heating rate of 3°C / second, there is one or more loss tangent peaks, and the peak temperature of all loss tangent peaks is 150°C or higher.

[0061] The inventors have discovered the following issues as a result of their in-depth research.

[0062] In addition to the matters in (I) and (iii) above, (iv) if the glass transition temperature of polymer component (A) is above 250°C, and in the dynamic viscoelasticity test obtained by heating from 25°C to 280°C at a heating rate of 3°C / second, there is more than one loss tangent peak in the curve representing the change of loss tangent with temperature, and the peak temperature of all loss tangent peaks is above 150°C, then the change in storage modulus and coefficient of linear expansion of the cured resin layer at high temperature can be reduced.

[0063] It should be noted that the aforementioned loss tangent peak can be obtained by performing peak separation on the curve representing the change of loss tangent with temperature obtained from a dynamic viscoelasticity measurement in which the temperature is increased from 25°C to 280°C at a heating rate of 3°C / second, using the fitting function as a Gaussian function. Furthermore, the temperature at the apex of each peak is taken as the peak temperature; specifically, the peak temperature of the loss tangent peak is determined according to the method described in the embodiments.

[0064] By setting the peak temperature of all loss tangent peaks to 150°C or higher, the peak temperature of the loss tangent is eliminated in the temperature range below 150°C. Therefore, even if the heating temperature during sputtering to form a transparent conductive material layer, the heating temperature during annealing of a transparent conductive material layer containing silver nanofillers, and the heating temperature for forming a gas barrier layer reach approximately 150°C, the optical film is less prone to deformation due to heating, thus facilitating the formation of transparent conductive and gas barrier layers. Furthermore, transparent conductive and gas barrier films that ensure the required conductivity and gas barrier properties are readily obtained. From this perspective, a peak temperature of all loss tangent peaks of 200°C or higher is more preferable.

[0065] In the loss tangent measurement curve obtained by the above dynamic viscoelasticity measurement, as a method to make the peak temperature of all loss tangent peaks of the optical film 150°C or higher, a third step can be implemented in the manufacturing method of the optical film described later.

[0066] In the optical film according to one embodiment of the present invention, as specified in (II) above, the reduction rate of the storage modulus calculated by the above formula (1) is 40% or less, and the reduction rate of the storage modulus is the reduction rate of the storage modulus from 25°C to 150°C. The reduction rate of the storage modulus is preferably 35% or less, more preferably 30% or less. The reduction rate of the storage modulus is specifically measured by the method described in the examples.

[0067] If the reduction rate of the aforementioned energy storage modulus is within the aforementioned range, then the optical film can withstand the thermal load when forming functional layers such as transparent conductive layers and gas barrier layers.

[0068] As a method for reducing the energy storage modulus to the range described above, one example is using a resin with a high glass transition temperature, as described later, as the polymer component (A).

[0069] Hereinafter, for easier understanding, the composition of each layer and film will be described with reference to the accompanying drawings and using the symbols shown in the drawings, but the present invention is not limited to the manner shown in the drawings.

[0070] Figure 1 This invention illustrates a specific configuration example of an optical film according to an embodiment of the present invention.

[0071] Figure 1 (a) The optical film 10A shown has a process film 1 on one side of the cured resin layer 2. As described later, a transparent conductive layer, a gas barrier layer, and other functional layers are provided on the side of the cured resin layer 2 opposite to the surface where the process film 1 is provided, and a transparent conductive film and a gas barrier film are made for use.

[0072] Figure 1 (b) The optical film 10B shown has process films 1A and 1B on both sides of the cured resin layer 2. When a functional layer such as a transparent conductive layer and a gas barrier layer is provided, any one of the process films 1A and 1B is peeled off and removed, and then a functional layer such as a transparent conductive layer and a gas barrier layer is provided on the exposed surface.

[0073] 1-1. Curing resin layer

[0074] The optical film according to embodiments of the present invention has a cured resin layer formed from a cured resin composition containing a polymer component (A) and a curable monomer (B). The cured resin layer may be a single layer or may comprise multiple layers stacked together.

[0075] [Polymer component (A)]

[0076] In the optical film according to one embodiment of the present invention, the glass transition temperature (Tg) of the polymer component (A) is 250°C or higher. The Tg of the polymer component (A) is preferably 290°C or higher, more preferably 320°C or higher. If the Tg of the polymer component (A) is 250°C or higher, it is easier to avoid the decrease in heat resistance due to the influence of polymers generated during the preparation of the curable composition together with the curable monomer (B) described later and the curing of the curable composition. As a result, the change in storage modulus and coefficient of linear expansion of the cured resin layer at high temperatures can be reduced, thereby easily preventing deformation of the cured resin layer due to heating during film formation, annealing treatment, etc., when forming functional layers such as transparent conductive layers and gas barrier layers.

[0077] Tg refers to the temperature at which the loss tangent (tanδ), expressed as loss modulus / storage modulus, is maximized by viscoelasticity measurement (measurement based on tensile mode in the range of 0–250°C at a frequency of 11 Hz and a heating rate of 3°C / min).

[0078] The weight-average molecular weight (Mw) of the polymer component (A) is preferably 100,000 or more, more preferably 200,000 or more, and preferably 1,000,000 or less, more preferably 800,000 or less, and even more preferably 500,000 or less.

[0079] Furthermore, the molecular weight distribution (Mw / Mn) of polymer component (A) is preferably in the range of 1.0 to 5.0, more preferably 2.0 to 4.5. The weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are values ​​converted from polystyrene obtained by gel permeation chromatography (GPC). By making Mw 100,000 or higher, it is easier to increase the elongation at break of the cured resin layer.

[0080] As the polymer component (A), a thermoplastic resin is preferred, and an amorphous thermoplastic resin is more preferred. By using an amorphous thermoplastic resin, it is easy to obtain a cured resin layer with excellent optical isotropy and an optical film with excellent transparency. In addition, since amorphous thermoplastic resins are substantially soluble in organic solvents, as described later, a cured resin layer can be efficiently formed by solution casting.

[0081] Here, amorphous thermoplastic resin refers to thermoplastic resin whose melting point was not observed in differential scanning calorimetry.

[0082] The polymer component (A) is particularly preferably those that are soluble in common low-boiling-point organic solvents such as ethyl acetate and methyl ethyl ketone (MEK). If it is soluble in common organic solvents, a cured resin layer can be easily formed by coating.

[0083] As polymer component (A), an amorphous thermoplastic resin that is soluble in common low-boiling-point organic solvents such as ethyl acetate and methyl ethyl ketone, and has a Tg of 250°C or higher is particularly preferred.

[0084] Furthermore, from the viewpoint of heat resistance, thermoplastic resins having ring structures such as aromatic ring structures or alicyclic structures are preferred as polymer component (A), and thermoplastic resins having aromatic ring structures are more preferred.

[0085] Specific examples of polymer component (A) include polyimide resins and polyarylate resins with a Tg of 250°C or higher. These resins generally have high Tg, excellent heat resistance, and are amorphous thermoplastic resins, thus allowing for coating formation using solution casting. Among these, polyimide resins are preferred due to their high Tg, excellent heat resistance, and ease of obtaining materials that exhibit good heat resistance while being soluble in common organic solvents.

[0086] As for the polyimide resin, there are no particular limitations as long as it does not impair the effects of the present invention. 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. Polyimide resins with intramolecular fluorine groups are particularly preferred.

[0087] Specifically, the preferred method is to use an aromatic diamine compound and a tetracarboxylic acid dianhydride, and to obtain a polyimide resin by polymerization into polyamic acid and chemical imidization reaction.

[0088] As an aromatic diamine compound, any aromatic diamine compound can be used as long as it is an aromatic diamine compound that is soluble in a common solvent (e.g., N,N-dimethylacetamide (DMAC)) and has a given transparency, obtained by reacting with a tetracarboxylic dianhydride used together. Specific examples include: 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-aminophenyl)-2 2,2-bis(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-aminophenyl)biphenyl Bis[4-(4-aminophenoxy)phenyl] sulfide, bis[3-(4-aminophenoxy)phenyl] sulfide, bis[4-(3-aminophenoxy)phenyl] sulfide, bis[3-(4-aminophenoxy)phenyl] sulfide, bis[3-(3-aminophenoxy)phenyl] sulfide, bis[3-(4-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-(3-aminophenoxy)phenyl]propane, 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]-1,1,1,3,3,3-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, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, etc.

[0089] These aromatic diamine compounds can be used alone or in combination with two or more. Furthermore, 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, 2,2-bis[3-(3-aminophenyl)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(3-aminophenyl)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4 ... Aromatic diamine compounds containing fluorine groups, such as [phenoxy)phenyl]-1,1,1,3,3,3-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, are preferred. It is especially preferred that at least one of the aromatic diamine compounds used is a fluorine-containing aromatic diamine compound, particularly 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl. By using aromatic diamine compounds containing fluorine groups, transparency, heat resistance, and solvent solubility are readily obtained.

[0090] As with the aromatic diamine compounds mentioned above, any tetracarboxylic dianhydride can be used as long as it is a polyimide that is soluble in a common solvent (e.g., N,N-dimethylacetamide (DMAC)) and has a given degree of transparency. Examples include: 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphthalic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 1,4-hydroquinone benzoate-3,3',4,4'-tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride. These tetracarboxylic dianhydrides can be used alone or in combination with two or more. Furthermore, from the viewpoints of transparency, heat resistance, and solvent solubility, tetracarboxylic dianhydrides having at least one fluorine group, such as 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphthalic dianhydride, are preferred.

[0091] Polyamic acid can be polymerized by reacting the above-mentioned aromatic diamine compound with a tetracarboxylic acid dianhydride in a solvent soluble in the polyamic acid to be produced. Solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, and dimethyl sulfoxide can be used as solvents for polymerizing polyamic acid.

[0092] The polymerization reaction to produce polyamic acid is preferably carried out in a reaction vessel equipped with a stirrer while stirring. Examples include: dissolving a given amount of aromatic diamine compound in the solvent, and adding tetracarboxylic dianhydride while stirring to obtain polyamic acid; dissolving tetracarboxylic dianhydride in a solvent, and adding aromatic diamine compound while stirring to obtain polyamic acid; alternately adding aromatic diamine compound and tetracarboxylic dianhydride to react and obtain polyamic acid; and so on.

[0093] There are no particular limitations on the polymerization temperature for polyamic acid, but it is preferably carried out at a temperature of 0–70°C, more preferably 10–60°C, and even more preferably 20–50°C. By carrying out the polymerization reaction within the above range, high molecular weight polyamic acid with less coloring and excellent transparency can be obtained.

[0094] Furthermore, the aromatic diamine compound and tetracarboxylic dianhydride used in the polymerization of polyamic acid are basically used in equimolar amounts. However, in order to control the degree of polymerization of the obtained polyamic acid, the molar ratio of tetracarboxylic dianhydride to aromatic diamine compound can be varied in the range of 0.95 to 1.05. Moreover, the molar ratio of tetracarboxylic dianhydride to aromatic diamine compound is preferably in the range of 1.001 to 1.02, more preferably 1.001 to 1.01. By making the tetracarboxylic dianhydride slightly in excess relative to the aromatic diamine compound, the degree of polymerization of the obtained polyamic acid can be stabilized, and the units from tetracarboxylic dianhydride can be arranged at the end of the polymer. As a result, polyimide with less coloring and excellent transparency can be obtained.

[0095] The concentration of the generated polyamic acid solution is preferably adjusted to a suitable concentration (e.g., about 10 to 30% by mass) so that the viscosity of the solution remains suitable and the operation in subsequent processes becomes easier.

[0096] An imidizing agent is added to the obtained polyamic acid solution to carry out a chemical imidization reaction. As the imide, carboxylic anhydrides such as acetic anhydride, propionic anhydride, succinic anhydride, phthalic anhydride, and benzoic anhydride can be used. From the viewpoints of cost and ease of removal after the reaction, acetic anhydride is preferred. The equivalent amount of the imidizing agent used is greater than or equal to the equivalent amount of the amide bond in the polyamic acid undergoing the chemical imidization reaction, preferably 1.1 to 5 times the equivalent amount of the amide bond, more preferably 1.5 to 4 times. By using an imidizing agent in slight excess relative to the amide bond, the imidization reaction can be carried out effectively even at relatively low temperatures.

[0097] In chemical imidization reactions, aliphatic, aromatic, or heterocyclic tertiary amines such as pyridine, methylpyridine, quinoline, isoquinoline, trimethylamine, and triethylamine can be used as imidization promoters. By using such amines, imidization reactions can be carried out effectively at low temperatures, resulting in the suppression of coloration during the imidization reaction and the easier acquisition of more transparent polyimides.

[0098] There are no particular limitations on the temperature of the chemical imidization reaction, but it is preferably carried out at a temperature above 10°C and below 50°C, and more preferably at a temperature above 15°C and below 45°C. By carrying out the chemical imidization reaction at a temperature above 10°C and below 50°C, coloring during the imidization reaction can be suppressed, thereby obtaining polyimides with excellent transparency.

[0099] Then, as needed, the polyimide is pulverized and dried. The pulverization is carried out by adding a poor solvent for polyimide to the polyimide solution obtained by chemical imidization reaction to precipitate the polyimide and thus form powder.

[0100] As a polyimide resin, it is preferably soluble in low-boiling-point organic solvents such as benzene and methyl ethyl ketone (MEK), and particularly preferably soluble in MEK. If it is soluble in MEK, a layer of curable resin composition can be easily formed by coating and drying.

[0101] From the viewpoint that it is easy to dissolve in common organic solvents with low boiling points such as methyl ethyl ketone, and thus easy to form a cured resin layer by coating, polyimide resins containing fluorine groups are particularly preferred.

[0102] As a polyimide resin containing fluorine groups, an aromatic polyimide resin having intramolecular fluorine groups is preferred, and a polyimide resin having an intramolecular skeleton represented by the following chemical formula is even more preferred.

[0103] [Chemical Formula 1]

[0104]

[0105] Polyimide resins having the skeleton shown in the above chemical formula exhibit extremely high Tg (temperature resistance) exceeding 300°C due to the high rigidity of the skeleton. Therefore, the heat resistance of the cured resin layer can be significantly improved. Furthermore, the linearity and high flexibility of the skeleton facilitates the improvement of the elongation at break of the cured resin layer. In addition, the polyimide resin having the above-mentioned skeleton, by having fluorine groups, is soluble in common low-boiling-point organic solvents such as methyl ethyl ketone. Therefore, it is possible to apply the resin using a solution casting method to form a cured resin layer in the form of a film, and the solvent can be easily removed by drying. Polyimide resins having the skeleton shown in the above chemical formula can be obtained by polymerization and imidization of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl and 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)phthalic dianhydride using the aforementioned polyamic acid.

[0106] Polyaryl ester resins are resins formed from high molecular weight compounds obtained by reacting aromatic diols with aromatic dicarboxylic acids or their acyl chlorides. Polyaryl ester resins also exhibit high Tg and good elongation properties. There are no particular limitations on the type of polyaryl ester resin used; those known to the public can be employed.

[0107] 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; 1,1-bis(4'-hydroxyphenyl)cyclopentane, 1,1-bis(4'-hydroxyphenyl)cyclohexane [bisphenol Z], 1,1-bis(4'-hydroxyphenyl)-3,3,5-trimethylcyclohexane, etc. (Hydroxyphenyl)cycloalkanes; 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-tert-butyl-4-hydroxyphenyl)phenylmethane, bis(3-phenyl-4-hydroxyphenyl)phenylmethane, bis(3-fluoro-4-hydroxyphenyl)phenylmethane, bis(3-bromo-4-hydroxyphenyl)phenylmethane, 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-dimethylphenyl)phenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethylphenyl)phenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxyphenyl)-4-chlorophenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxyphenyl)-4-bromophenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(3,5-dimethylphenylmethane, bis(3,5-dimethylphenylmethane, bis(3,5-dimethylphenylmethane, bis(3,5-dimethyl 1,1-bis(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'-tert-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)dibenzylmethane, and other bis(hydroxyphenyl)phenylalkanes Classes; bis(4-hydroxyphenyl) ethers, bis(3-methyl-4-hydroxyphenyl) ethers, etc.; bis(4-hydroxyphenyl) ketones, bis(3-methyl-4-hydroxyphenyl) ketones, etc.; bis(4-hydroxyphenyl) sulfides, bis(3-methyl-4-hydroxyphenyl) sulfides, etc.; bis(4-hydroxyphenyl) sulfoxides, bis(3-methyl-4-hydroxyphenyl) sulfoxides, etc.; bis(hydroxyphenyl) sulfoxides, bis(4-hydroxyphenyl) sulfoxides, etc.; bis(4-hydroxyphenyl) sulfones [bisphenol S], bis(3-methyl-4-hydroxyphenyl) sulfones, etc.; 9,9-bis(4'-hydroxyphenyl)fluorene, 9,9-bis(3'-methyl-4'-hydroxyphenyl)fluorene, etc.; etc.

[0108] Examples of aromatic dicarboxylic acids or their acyl chlorides include phthalic acid, isophthalic acid, terephthalic acid, 4,4'-biphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ether 4,4'-dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and their acyl chlorides. Furthermore, the polyaryl ester resin used may also be a modified polyaryl ester resin. Among these, a resin formed from a polymer compound obtained by the reaction of 2,2-bis(4'-hydroxyphenyl)propane and isophthalic acid is preferred as a polyaryl ester resin.

[0109] Polymer component (A) can be used alone or in combination of two or more. Furthermore, polymer component (A) can be a combination of polymer component (A') with a Tg of 250°C or higher and polymer component (A”) with a Tg of less than 250°C. Examples of polymer component (A”) include polyamide resin and polyarylate resin with a Tg of less than 250°C, with polyamide resin being preferred.

[0110] As polyamide resins, those soluble in organic solvents are preferred, and rubber-modified polyamide resins are even more preferred. As rubber-modified polyamide resins, those described, for example, in Japanese Patent Application Publication No. 2004-035638 can be used.

[0111] From the viewpoints of being able to adjust elongation characteristics and solvent resistance, polymer components (A) and (A”) are preferably obtained by using a single type of polyimide resin, polymer components obtained by using multiple different types of polyimide resin, and polymer components obtained by adding at least one of polyamide resin and polyarylate resin to polyimide resin.

[0112] When polyamide resin and polyarylate resin with a Tg of less than 250°C are added to polyimide resin, from the viewpoint of maintaining a high Tg and imparting appropriate softness, the amount of added resin is preferably 100 parts by weight or less, more preferably 70 parts by weight or less, further preferably 50 parts by weight or less, and even more preferably 30 parts by weight or less, and preferably 1 part by weight or more, more preferably 3 parts by weight or more, relative to 100 parts by weight of polyimide resin.

[0113] [Cureable Monomer (B)]

[0114] Curable monomer (B) is a monomer with polymerizable unsaturated bonds; it is a monomer that participates in polymerization or is capable of participating in polymerization. By using curable monomer (B), the drying efficiency of obtaining a cured resin layer through coating and drying is improved, and the cured resin layer is easily peeled off from the process film. Furthermore, optical films with excellent solvent resistance can be obtained.

[0115] By making the cured resin layer a cured layer formed from the cured resin composition containing the polymer component (A) and the cured monomer (B) described above, it is easy to form a thin cured resin layer with excellent heat resistance. In addition, if such a material is used, optical problems arising from materials with anisotropic molecular orientation, such as polyester films commonly used as substrates for optical films, will not occur.

[0116] The molecular weight of the curable monomer (B) is typically 3,000 or less, preferably 200 to 2,000, and more preferably 200 to 1,000. If the molecular weight of the curable monomer (B) is in such a range, the skinning phenomenon described later can be suppressed more effectively when forming a coating film of the curable resin composition.

[0117] Examples of curable monomers (B) include monofunctional (meth)acrylic acid derivatives and polyfunctional (meth)acrylic acid derivatives. From the perspective of obtaining a cured resin layer with superior heat resistance and solvent resistance, polyfunctional (meth)acrylic acid derivatives are preferred. As polyfunctional (meth)acrylic acid derivatives, from the viewpoint that they are easily mixed with polymer component (A) and do not easily cause curing shrinkage of the polymer, thus suppressing curling of the cured product, difunctional (meth)acrylic acid derivatives are preferred.

[0118] There are no particular limitations on the use of monofunctional (meth)acrylic acid derivatives; known compounds can be used. Examples include: monofunctional (meth)acrylic acid derivatives having a nitrogen atom, monofunctional (meth)acrylic acid derivatives having an alicyclic structure, and monofunctional (meth)acrylic acid derivatives having a polyether structure.

[0119] As monofunctional (meth)acrylic acid derivatives with nitrogen atoms, compounds represented by the following formulas can be listed.

[0120] [Chemical Formula 2]

[0121]

[0122] In the formula, R 1 R represents an alkyl group having 1 to 6 hydrogen atoms or carbon atoms. 2 and R 3 Each of the following is an organic group that independently represents 1 to 12 hydrogen or carbon atoms: R 2 and R3 They can bond together to form a ring structure, R 4 This indicates a divalent organic group.

[0123] As R 1 The alkyl group representing 1 to 6 carbon atoms can be exemplified by methyl, ethyl, propyl, etc., with methyl being the most preferred.

[0124] As R 2 and R 3 Organic groups representing 1 to 12 carbon atoms include: alkyl groups such as methyl, ethyl, and propyl with 1 to 12 carbon atoms; cycloalkyl groups such as cyclopentyl and cyclohexyl with 3 to 12 carbon atoms; and aromatic groups such as phenyl, biphenyl, and naphthyl with 6 to 12 carbon atoms. These groups can have substituents at any position. Additionally, R... 2 and R 3 They can form a ring together, and the ring can further contain nitrogen and oxygen atoms in the framework.

[0125] As R 4 Examples of divalent organic groups include -(CH2). m -、-NH-(CH2) m - represents a group, where m is an integer from 1 to 10.

[0126] Among these, (meth)acryloylmorpholine, represented by the following formula, is a preferred example of a monofunctional (meth)acrylic acid derivative having a nitrogen atom.

[0127] [Chemical Formula 3]

[0128]

[0129] By using a monofunctional (meth)acrylic acid derivative with nitrogen atoms as the curing monomer (B), a cured resin layer with superior heat resistance can be formed.

[0130] Compounds represented by the following formulas can be listed as monofunctional (meth)acrylic acid derivatives with an alicyclic structure.

[0131] [Chemical Formula 4]

[0132]

[0133] In the formula, R 1 R represents the same meaning as above. 5 It is a group with an alicyclic structure.

[0134] As R 5 Examples of alicyclic groups include cyclohexyl, isobornyl, 1-adamantyl, 2-adamantyl, tricyclodecyl, etc.

[0135] Specific examples of monofunctional (meth)acrylic acid derivatives with an alicyclic structure include: isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, 1-adamantane (meth)acrylate, 2-adamantane (meth)acrylate, etc.

[0136] By using a monofunctional (meth)acrylic acid derivative with an alicyclic structure as the curing monomer (B), a cured resin layer with superior optical properties can be formed.

[0137] Compounds represented by the following formulas can be listed as monofunctional (meth)acrylic acid derivatives with polyether structures.

[0138] [Chemical Formula 5]

[0139]

[0140] In the formula, R 1 R represents the same meaning as above. 6 This refers to an organic group containing 1 to 12 carbon atoms. As R 6 Organic groups with 1 to 12 carbon atoms can be represented by: alkyl groups with 1 to 12 carbon atoms such as methyl, ethyl, and propyl; cycloalkyl groups with 3 to 12 carbon atoms such as cyclohexyl; aromatic groups with 6 to 12 carbon atoms such as phenyl, biphenyl, and naphthyl; and so on. j represents an integer from 2 to 20.

[0141] Specific examples of monofunctional (meth)acrylic acid derivatives with polyether structures include: ethoxylated o-phenylphenol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, etc.

[0142] By using a monofunctional (meth)acrylic acid derivative with a polyether structure as the curing monomer (B), a curing resin layer with excellent toughness can be formed.

[0143] There are no particular limitations on the use of (meth)acrylic acid derivatives, and known compounds can be used. Examples include (meth)acrylic acid derivatives with 2 to 6 functions, with (meth)acrylic acid derivatives with 2 functions preferred as described above.

[0144] As difunctional (meth)acrylic acid derivatives, compounds represented by the following formulas can be listed.

[0145] [Chemical Formula 6]

[0146]

[0147] In the formula, R 1 R represents the same meaning as above.7 This represents a divalent organic group. As R 7 The divalent organic groups can be represented by the following formulas.

[0148] [Chemical Formula 7]

[0149] -O-(CH2) s -O-

[0150] -O(CH2CH2O) t -

[0151]

[0152] (In the formula, s represents an integer from 1 to 20, t represents an integer from 1 to 30, u and v each independently represent an integer from 1 to 30, and the "-" at both ends represent bonding arms.)

[0153] Specific examples of difunctional (meth)acrylic acid derivatives represented by the above chemical formulas include: tricyclodecanediethanol 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, etc. Among these, from the viewpoint of heat resistance and toughness, tricyclodecanediethanol di(meth)acrylate, etc., in which R is represented by the chemical formula above are preferred. 7 The divalent organic groups indicated are those with a tricyclic decane skeleton; propoxylated ethoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, etc., in the above chemical formula R 7 The divalent organic groups represented are those with a bisphenol skeleton; 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, etc., in the above chemical formula R 7 The divalent organic groups represented are those having a 9,9-bisphenylfluorene skeleton.

[0154] In addition, other difunctional (meth)acrylic acid derivatives include: neopentyl glycol hexanediol di(meth)acrylate, neopentyl glycol hydroxypentanoate di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate phosphate, di(acryloyloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, etc.

[0155] 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 tri(acryloyloxyethyl)isocyanurate.

[0156] Examples of tetrafunctional (meth)acrylic acid derivatives include pentaerythritol tetra(meth)acrylate.

[0157] Examples of 5-functional (meth)acrylic acid derivatives include propionic acid-modified dipentaerythritol penta(meth)acrylate.

[0158] Examples of hexafunctional (meth)acrylic acid derivatives include: dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc.

[0159] As the curable monomer (B), a cyclizable monomer can be used. A cyclizable monomer is a monomer that, although cyclized, still retains the property of undergoing free radical polymerization. Examples of cyclizable monomers include non-conjugated dienes, such as α-allyloxymethacrylic acid monomers, preferably alkyl esters of 2-acryloyloxymethacrylic acid with 1 to 4 carbon atoms, cyclohexyl 2-(allyloxymeth)acrylate, more preferably alkyl esters of 2-acryloyloxymethacrylic acid with 1 to 4 carbon atoms, and even more preferably methyl 2-(acryloyloxymeth)acrylate.

[0160] Alternatively, the following cyclized monomers can also be used: dimethyl 2,2'-[oxybis(methylene)]bis-2-propionate, diethyl 2,2'-[oxybis(methylene)]bis-2-propionate, di-n-propyl 2,2'-[oxybis(methylene)]bis-2-propionate, diisopropyl 2,2'-[oxybis(methylene)]bis-2-propionate, di-n-butyl 2,2'-[oxybis(methylene)]bis-2-propionate, di-n-hexyl 2,2'-[oxybis(methylene)]bis-2-propionate, and dicyclohexyl 2,2'-[oxybis(methylene)]bis-2-propionate.

[0161] Curable monomer (B) can be used alone or in combination of two or more.

[0162] As the curing monomer (B), it is more preferable to include a polyfunctional (meth)acrylic acid derivative and a cyclizable monomer. By using them in combination, the heat resistance of the cured resin layer can be easily adjusted to a suitable level, and the elongation at break of the cured resin layer can be easily adjusted to a given range.

[0163] When the curable monomer (B) contains a polyfunctional (meth)acrylic acid derivative, its content is preferably 40% by mass or more, more preferably 50 to 100% by mass, of the total amount of curable monomer (B).

[0164] [Curing Resin Composition]

[0165] The curable resin composition used to form the curable resin layer according to embodiments of the present invention can be prepared by mixing polymer component (A), curable monomer (B), and polymerization initiator and other components as described below as needed, and dissolving or dispersing them in a suitable solvent.

[0166] The total content of polymer component (A) and curing component (B) in the curing resin composition is preferably 40 to 99.5% by mass, more preferably 60 to 99% by mass, and even more preferably 80 to 98% by mass, relative to the total mass of the curing resin composition excluding the solvent.

[0167] The content of polymer component (A) and curable monomer (B) in the curable resin composition is based on the mass ratio of polymer component (A) to curable monomer (B), preferably polymer component (A):curable monomer (B) = 30:70 to 90:10, more preferably 35:65 to 80:20.

[0168] In a curable resin composition, by keeping the mass ratio of polymer component (A) to curable monomer (B) within such a range, there is a tendency for the resulting cured resin layer to have its flexibility further improved, its solvent resistance, and its peelability from the process film to be easily maintained.

[0169] Furthermore, when the content of curable monomer (B) in the curable resin composition is within the above range, for example, when a cured resin layer is obtained by solution casting, the solvent can be removed efficiently, thus eliminating problems such as curling and ripples caused by prolonged drying processes.

[0170] As polymer component (A), when using a combination of multiple resins with different solvent solubility, such as the above-mentioned combination of polyimide resin and polyamide resin or polyarylate resin, it is preferable to first dissolve the resin in a solvent suitable for each of them, and then add the solution containing the other resins to a low-boiling-point organic solvent in which the resin is dissolved.

[0171] The curable resin composition may contain a polymerization initiator as needed. The polymerization initiator can be used without particular restriction as long as it is a component that initiates the curing reaction; examples include photopolymerization initiators.

[0172] Examples of photopolymerization initiators include: 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propanoyl)benzyl]phenyl]-2-methyl-propane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-benzyl-2- Alkyl benzophenone photoinitiators such as dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone; phosphorus photoinitiators such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenyl phosphate, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; bis(η 5 Dioctane photoinitiators such as 2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl]titanium; oxime ester photoinitiators such as 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyl oxime)] and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl] acetone-1-(O-acetyl oxime); benzophenone, p-chlorobenzophenone, benzoylbenzoic acid, methyl o-benzoylbenzoate, 4-methylbenzophenone, 4-phenylbenzophenone, hydroxybenzophenone, and acrylated benzophenone. Benzyl-4'-methyl-diphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone, 4-(13-acryloyl-1,4,7,10,13-pentaoxetane)benzophenone and other benzophenone-based photopolymerization initiators; thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone and other thioxanthone-based photopolymerization initiators; and so on.

[0173] Among the above-mentioned 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)phenyl phosphate, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide are preferred.

[0174] When polymer component (A) is a thermoplastic resin with aromatic rings, it absorbs ultraviolet light, which sometimes makes the curing reaction difficult. However, by using the aforementioned phosphorus-based photopolymerization initiator, the curing reaction can be carried out efficiently using light of wavelengths that are not absorbed by the polymer component (A).

[0175] Polymerization initiators can be used alone or in combination of two or more.

[0176] The content of the polymerization initiator relative to the entire curable resin composition 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.

[0177] In addition, the curable resin composition may contain photopolymerization initiators such as triisopropanolamine and 4,4'-diethylaminobenzophenone, in addition to the polymer component (A), curable monomer (B) and polymerization initiator.

[0178] There are no particular limitations on the solvents used in preparing curable resin compositions. Examples include: aliphatic hydrocarbon solvents such as n-hexane and n-heptane; aromatic hydrocarbon solvents such as toluene and xylene; halogenated hydrocarbon solvents such as dichloromethane, vinyl chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, and monochlorobenzene; alcohol 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; ester solvents such as ethyl acetate and butyl acetate; cellosol solvents such as ethyl cellosol; ether solvents such as 1,3-dioxolane; and so on.

[0179] The solvent content in the curable resin composition is not particularly limited, but is typically 0.1 to 1000 g, preferably 1 to 100 g, relative to 1 g of polymer component (A). By appropriately adjusting the amount of solvent, the viscosity of the curable resin composition can be adjusted to an appropriate value.

[0180] In addition, the curable resin composition may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, without impairing the purpose or effect of the present invention.

[0181] The method for curing the curable resin composition can be appropriately determined depending on the type of polymerization initiator and curable monomer used. Details will be explained later in the section on the manufacturing method of optical films.

[0182] [Properties of the cured resin layer, etc.]

[0183] As described above, the cured resin layer exhibits more than one loss tangent peak in the curve representing the change of the loss tangent with temperature obtained from a dynamic viscoelasticity measurement conducted by heating from 25°C to 280°C at a heating rate of 3°C / second. Furthermore, the cured resin layer of the optical film according to one embodiment of the present invention, as described above, has a storage modulus reduction rate of 40% or less. In addition to these characteristics, the cured resin layer also possesses the following properties.

[0184] The thickness of the cured resin layer is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 12 μm or less, and even more preferably 10 μm or less. There is no particular limitation on the lower limit of the thickness of the cured resin layer, but it is typically 0.1 μm or more, preferably 0.2 μm or more.

[0185] It should be noted that when the cured resin layer comprises multiple stacked layers, the thickness of the cured resin layer is the overall thickness including all the multiple layers.

[0186] When the thickness of the cured resin layer is less than 20 μm, it is easy to obtain a thin and lightweight optical film, thereby enabling the production of an optical film with excellent operability.

[0187] Furthermore, due to the thinness of the cured resin layer, high transparency is achieved, resulting in thin and lightweight transparent conductive films and gas barrier films. Therefore, in applications requiring thinness, such as organic EL displays, the transparent conductive film and gas barrier film are preferred because they do not contribute to an increase in the overall thickness of the application device. Additionally, a thin transparent conductive film and gas barrier film improve the flexibility and bending resistance after installation.

[0188] In the embodiments of the present invention, the absolute value of the thermal deformation rate of the cured resin layer based on a temperature rise of 150°C is preferably 1.2% or less, more preferably 1.1% or less, and even more preferably 1.0% or less. By setting the absolute value of the thermal deformation rate of the cured resin layer based on a temperature rise of 150°C to the above-mentioned range, the cured resin layer readily exhibits good heat resistance. In the case of forming a transparent conductive layer by heating a conductive material layer, or in the case of forming a gas barrier layer, it is easy to suppress the reduction of the performance of the transparent conductive layer and the gas barrier layer due to deformation of the cured resin layer caused by heating.

[0189] In particular, by forming a conductive material layer on a cured resin layer through sputtering, evaporation, or coating, and then heating the conductive material layer to form a transparent conductive layer, or by applying a coating liquid for forming a gas barrier layer and then heating it to form a gas barrier layer, even if a transparent conductive film or gas barrier film is produced by a heating process after forming the cured resin layer, the high heat resistance of the cured resin layer can prevent difficulties in forming the transparent conductive layer or gas barrier layer due to deformation of the cured resin layer. Furthermore, it can prevent the transparent conductive layer from failing to exhibit sufficient electrical properties and the gas barrier layer from failing to exhibit sufficient gas barrier properties. From the same point of view, the absolute value of the thermal deformation rate of the cured resin layer based on a temperature rise of 150°C is preferably 0.8% or less.

[0190] The thermal deformation rate of the cured resin layer was determined using the following method. It should be noted that the thickness of the cured resin layer was adjusted to 20 μm for the measurement to avoid the following problem: a thin cured resin layer would cause elongation when mounted on the thermomechanical analyzer fixture.

[0191] Four layers of cured resin, after the process film has been removed, were stacked to form a laminate with a thickness of 20 μm. Next, test pieces of 5 mm × 30 mm were cut, and the laminate was held using a thermomechanical analyzer (NETZSCH Japan Inc. TMA4000SE) with a clamping distance of 20 mm. The laminate was then heated from 25 °C to 150 °C at a rate of 5 °C / min, and then cooled to 25 °C at a rate of 5 °C / min. The rate of change of displacement in the longitudinal direction before and after heating (expressed as a percentage of displacement relative to a clamping distance of 20 mm) was then used as the thermal deformation rate of the cured resin layer. The laminate was negative when shrinking and positive when elongating.

[0192] The cured resin layer also exhibits excellent solvent resistance. Due to this superior solvent resistance, even when organic solvents are used to form other layers on the surface of the cured resin layer, the surface of the cured resin layer hardly dissolves. Therefore, even when a transparent conductive layer is formed on the surface of the cured resin layer using a resin solution containing organic solvents and a coating method, or when a gas barrier layer is formed using a coating liquid of a polysilazane-based gas barrier layer, it is difficult for components of the cured resin layer to be mixed into the transparent conductive layer or the gas barrier layer. Therefore, the electrical properties of the transparent conductive layer and the gas barrier properties of the gas barrier layer are not easily reduced.

[0193] From this perspective, the gel fraction of the cured resin layer is preferably 94% or more, more preferably 97% or more. A cured resin layer with a gel fraction of 94% or more has a low residual amount of curable monomer (B) after curing, making it easier to obtain a cured resin layer that satisfies the aforementioned requirement (I).

[0194] Here, the gel fraction is obtained as follows: a 100mm×100mm cured resin layer is wrapped with a 150mm×150mm nylon mesh (#120) with a pre-determined mass, immersed in toluene (100mL) for 3 days, taken out and dried at 120°C for 1 hour, then placed at 23°C and 50% relative humidity for 3 hours to adjust the humidity, and its mass is measured. The gel fraction is obtained by the following formula (2).

[0195] Gel fraction (%) = [(mass of residual resin after impregnation) / (mass of resin before impregnation)] × 100 ··· Equation (2)

[0196] The interlayer adhesion between the cured resin layer and functional layers such as the transparent conductive layer and the gas barrier layer is excellent. That is, functional layers such as the transparent conductive layer and the gas barrier layer can be formed without setting an adhesion-enhancing coating on the cured resin layer.

[0197] The cured resin layer is preferably colorless and transparent. By making the cured resin layer colorless and transparent, the optical film of the embodiments of the present invention can be preferably used for optical applications. Specifically, the total light transmittance of the optical film of the embodiments of the present invention is preferably 85% or more, more preferably 90% or more. The total light transmittance is a characteristic value measured by the method described in the examples.

[0198] The cured resin layer exhibits low birefringence and excellent optical isotropy. The in-plane phase difference of the cured resin layer is typically less than 20 nm, preferably less than 15 nm. The phase difference along the thickness direction is typically less than -500 nm, preferably less than -450 nm. Furthermore, the birefringence obtained by dividing the in-plane phase difference by the thickness of the cured resin layer is typically 100 × 10⁻⁶. -5 The following, preferably 20×10 -5 the following.

[0199] If the in-plane phase difference, thickness direction phase difference, and birefringence of the cured resin layer are within the above range, an optical film with low birefringence and excellent optical isotropy can be obtained. Transparent conductive films and gas barrier films made using this optical film can be preferably used for optical applications.

[0200] The elongation at break of the cured resin layer is preferably 2.5% or more, more preferably 2.6% or more, and even more preferably 2.7% or more. If the elongation at break of the cured resin layer is 2.5% or more, it is easy to adjust the elongation at break of the optical film to 2% or more, resulting in an optical film with excellent flexibility. The elongation at break can be measured according to JIS K 7127:1999.

[0201] 1-2. Process membrane

[0202] The process film serves to protect the cured resin layer and other arbitrarily configured layers described later when storing and handling optical films, transparent conductive films, and gas barrier films, and is peeled off in a given process.

[0203] The process film may have a substrate layer, for example. The process film may also have other layers besides the substrate layer; as these other layers, a release layer may be provided. Since the cured resin layer is a cured product of a cured resin composition containing a curable monomer (B), it is easily peeled off from the process film even if a release layer is not provided on it.

[0204] Optical films, by incorporating a process film, can protect the cured resin layer and form highly processable optical films. Optical films can be as described above. Figure 1 As shown in (a), a process film can be formed on one side of the cured resin layer, or it can be as described above. Figure 1 (b) shows that the cured resin layer has process films on both sides. In the latter case, it is preferable to use two types of process films, and the process film to be peeled off first is set to be easier to peel off than the other process film.

[0205] The process membrane is preferably in the form of a sheet or a film. Here, sheet or film is not limited to long strips, but also includes short flat sheets.

[0206] Examples of substrate layers for process films include: paper substrates such as cellophane, coated paper, and high-grade paper; laminated paper made by laminating thermoplastic resins such as polyethylene and polypropylene onto these paper substrates; materials made by filling the gaps in the aforementioned paper substrates using cellulose, starch, polyvinyl alcohol, acrylic-styrene resin, etc.; or plastic films such as polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polyethylene and polypropylene; and glass, etc.

[0207] The release layer can be formed using conventionally known release agents such as silicone-based release agents, fluorinated release agents, alkyd release agents, and olefin-based release agents.

[0208] There is no particular limitation on the thickness of the release layer, which is typically 0.02 to 2.0 μm, more preferably 0.05 to 1.5 μm.

[0209] From the perspective of ease of operation, the thickness of the process membrane is preferably 1 to 500 μm, more preferably 5 to 300 μm.

[0210] The average surface roughness (arithmetic mean roughness Ra) of the surface of the cured resin layer on which the process film is disposed is preferably 10 nm or less, more preferably 8.0 nm or less, and even more preferably 5.0 nm or less. Furthermore, the maximum surface roughness (maximum cross-sectional height Rt) of the surface of the cured resin layer on which the substrate layer of the process film is disposed is preferably 100 nm or less, more preferably 70 nm or less, and even more preferably 50 nm or less. There are no particular limitations on the lower limits of the average surface roughness and the maximum surface roughness; typically, the average surface roughness is 0.3 nm or more, and the maximum surface roughness is 10 nm or more.

[0211] By setting the average surface roughness of the cured resin layer to below 10 nm and the maximum surface roughness to below 100 nm in the substrate layer of the process film, the increase in haze of the cured resin layer can be suppressed.

[0212] It should be briefly noted that in this specification, "maximum surface roughness" refers to the maximum cross-sectional height Rt, and "average surface roughness" refers to the arithmetic mean roughness Ra. Both values ​​are obtained by optical interferometry over a measurement area of ​​100μm × 100μm.

[0213] 1-3. Other layers

[0214] Process films may have layers other than release layers, such as easy-to-adhere layers and antistatic layers.

[0215] In the layers constituting the optical film, the portion (separation layer) peeled off from the process film during a given process includes a cured resin layer. Since the cured resin layer is laminated onto the process film without interleaving other layers, it is located on one of the outermost surfaces of the separation layer. An easy-to-adhere layer, an antistatic layer, etc., other than the cured resin layer, can be provided on the other surface of the separation layer. However, since the separation layer is the layer constituting the transparent conductive film and the gas barrier film after the process film is removed, it is preferable to have a thinner layer, and the number and thickness of layers other than the cured resin layer are preferably kept to a minimum.

[0216] 2. Transparent conductive film

[0217] The transparent conductive film according to embodiments of the present invention has a transparent conductive layer on the cured resin layer of the aforementioned optical film. In other words, the transparent conductive film sequentially comprises a process film, a cured resin layer, and a transparent conductive layer. In actual use, the process film is peeled off from the transparent conductive film and then inserted into a display, a solar cell panel, or adhered to the substrate of a touch sensor for a touch panel. Regarding the method of applying the transparent conductive film to the application area, for example, when the transparent conductive film has an adhesive layer as described later, it can be adhered to the application area using the adhesive layer, and the process film can be peeled off after adhesion.

[0218] Figure 2 (a) and Figure 2 (b) shows a specific example of the structure of the transparent conductive film according to an embodiment of the present invention.

[0219] Figure 2 (a) The transparent conductive film 20 shown has a transparent conductive layer 3 on one side of the cured resin layer 2 and a process film 1 on the side of the cured resin layer 2 opposite to the transparent conductive layer 3.

[0220] The transparent conductive layer 3 is formed, for example, in a manner that covers the entire surface of the cured resin layer 2. Furthermore, the transparent conductive layer 3 can be patterned into a desired shape using suitable methods such as etching. Figure 2 (b) The transparent conductive film 21 shown has a patterned transparent conductive layer 31 on one side of the cured resin layer 2. It should be noted that a transparent conductive layer 31 with a desired pattern shape can also be formed on the cured resin layer 2 by selectively depositing a transparent conductive material on the cured resin layer 2 without the need for etching or other processes.

[0221] The process membrane 1 is removed from its current position. Figure 2 (a) Figure 2 When peeling off the transparent conductive film in the state shown in (b), from the viewpoint of easily reducing operability, it is preferable to peel off the process film 1 after the transparent conductive film has been applied to the applied part such as the adherend.

[0222] The thickness of the transparent conductive film can be appropriately determined according to the intended application. From an operational point of view, the substantial thickness of the transparent conductive film according to the embodiments of the present invention is preferably 0.3 to 50 μm, more preferably 0.5 to 25 μm, and even more preferably 0.7 to 12 μm.

[0223] It should be noted that the term "substantial thickness" refers to the thickness in the usage state. That is, although the aforementioned transparent conductive film has a process film, the thickness of the portion (process film, etc.) that is removed during use is not included in the "substantial thickness".

[0224] In this specification, "transparent" in transparent conductive film means that the light transmittance at a wavelength of 450nm is greater than 80%.

[0225] Conductive materials that can form transparent conductive layers include: metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples include: antimony-doped tin oxide (ATO); fluorine-doped tin oxide (FTO); semi-conductive 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 with conductive metal oxides; inorganic conductive materials such as copper iodide and copper sulfide; organic conductive materials such as polyaniline, polythiophene, and polypyrrole; and so on. Metals such as silver can also form transparent conductive layers by aggregating materials in a particulate state, such as nanofillers, nanorods, and nanofibers.

[0226] There are no particular restrictions on the methods for forming transparent conductive layers. Examples include: vapor deposition, sputtering, ion plating, thermal CVD, and plasma CVD.

[0227] Alternatively, a transparent conductive layer can be obtained by coating an optical film with a coating material containing particulate metal. More specifically, it is preferable to form a conductive material layer by PVD, CVD, or by applying and drying a coating material as described above, and then heating the conductive material layer to 140°C or higher using an electric furnace or the like to crystallize the conductive material, thereby forming a transparent conductive layer.

[0228] When using a cured resin layer with low heat resistance due to the heat treatment following such evaporation, sputtering, or coating processes, there is a concern that the cured resin layer may deform. Deformation of the cured resin layer could adversely affect the conductivity of the transparent conductive layer of the transparent conductive film. However, the cured resin layer of the transparent conductive film according to the embodiments of the present invention exhibits excellent heat resistance, making it less prone to deformation even when subjected to heat in such processes. Therefore, a decrease in the conductivity of the transparent conductive film due to deformation of the cured resin layer can also be avoided.

[0229] An adhesive layer can be applied to the transparent conductive layer after the transparent conductive film is obtained.

[0230] The thickness of the transparent conductive layer can be appropriately selected according to its application, and is usually 10nm to 50μm, preferably 20nm to 20μm.

[0231] The transparent conductive film involved in the embodiments of the present invention is not limited to having Figure 2 (a) Figure 2 The configuration shown in (b) may further include one or more other layers without prejudice to the purpose of the present invention.

[0232] Other possible layers include, for example, adhesive layers, impact-absorbing layers, hard coatings, and refractive index adjustment layers (refractive index matching layers). Furthermore, the placement of these other layers is not particularly restricted.

[0233] The adhesive layer is used when bonding the transparent conductive film to the substrate. There are no particular limitations on the material used to form the adhesive layer; known adhesives or heat-sealing materials such as acrylics, silicones, and rubbers can be used. In the case where the adhesive layer is formed on the side opposite to the surface of the cured resin layer facing the direction of the process film, after bonding the transparent conductive film to the substrate using the adhesive layer, the process film can be peeled off. This allows for the easy formation of a thin film containing both the cured resin layer and the transparent conductive layer onto the substrate. With the transparent conductive film according to the embodiments of the present invention, since the process film is flexible, such bonding can be easily performed, and peeling off the process film is also easy. The transparent conductive film may also have a release film on the side of the adhesive layer opposite to the direction of the cured resin layer to protect the adhesive layer. With this configuration, the transparent conductive film has a process film and a release film on its outermost layers on both sides, making operation convenient.

[0234] 3. Gas barrier membrane

[0235] The gas barrier film comprises a gas barrier layer and a cured resin layer. The aforementioned gas barrier film sequentially comprises a process film, a cured resin layer, and a gas barrier layer. The gas barrier film may also have two or more gas barrier layers.

[0236] Figure 2 (c) shows a specific example of the structure of the gas barrier membrane according to an embodiment of the present invention.

[0237] Figure 2 (c) The gas barrier film 22 shown has a gas barrier layer 4 on one side of the cured resin layer 2 and a process film 1 on the side of the cured resin layer 2 opposite to the gas barrier layer 4.

[0238] The process membrane 1 is removed from its current position. Figure 2 When the gas barrier film 22 in the state shown in (c) is peeled off, from the viewpoint of easily reducing operability, it is preferable to peel off the process film 1 after the gas barrier film 22 has been applied to the applied part such as the adhered object.

[0239] The gas barrier layer and the cured resin layer can be directly laminated together, or they can be laminated with other layers sandwiched between them. Other layers that can be included in a gas barrier film include adhesive layers, impact-absorbing layers, etc.

[0240] Multiple sets of cured resin layers and gas barrier layers can be stacked. In this case, other layers may exist between at least one set of cured resin layers and gas barrier layers.

[0241] The water vapor permeability of the gas barrier membrane in an atmosphere of 40℃ and 90% relative humidity is typically 1.0 × 10⁻⁶. -2 g / m 2 / day or less, preferably 8.0×10 -3 g / m 2 / day or less, preferably 6.0×10 -3 g / m 2 / day or less.

[0242] In the embodiments of the present invention, the gas barrier layer in the gas barrier film is not particularly limited in terms of its material, as long as it has gas barrier properties. Examples include: gas barrier layers formed from inorganic films, gas barrier layers containing gas barrier resins, and gas barrier layers obtained by modifying layers containing polymer compounds.

[0243] Among these, from the perspective of being able to efficiently form thin layers with excellent gas barrier properties and solvent resistance, gas barrier layers are preferably formed from inorganic films or obtained by modifying layers containing polymer compounds.

[0244] There are no particular limitations on the inorganic films mentioned above; for example, inorganic vapor-deposited films can be listed.

[0245] As inorganic vapor deposition films, examples include vapor deposition films of inorganic compounds and metals.

[0246] Raw materials for inorganic compound vapor-deposited films include: inorganic oxides such as silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, indium oxide, and tin oxide; inorganic nitrides such as silicon nitride, aluminum nitride, and titanium nitride; inorganic carbides; inorganic sulfides; inorganic nitrogen oxides such as silicon oxynitride; inorganic carbon oxides; inorganic carbonitrides; and inorganic carbonitrides.

[0247] Examples of raw materials for metal vapor deposition films include aluminum, magnesium, zinc, and tin.

[0248] These materials can be used alone or in combination of two or more.

[0249] The thickness of inorganic vapor-deposited films is typically in the range of 10 to 2,000 nm.

[0250] Methods for forming inorganic vapor-deposited films include: PVD (physical vapor deposition) methods such as vacuum evaporation, sputtering, and ion plating; CVD methods such as thermal CVD (chemical vapor deposition), plasma CVD, and photocatalytic CVD. When using a cured resin layer with low heat resistance due to the heating during such evaporation or sputtering, there is a concern that the cured resin layer may deform. Deformation of the cured resin layer may adversely affect the gas barrier properties of the gas barrier film. However, the cured resin layer of the gas barrier film according to the embodiments of the present invention has excellent heat resistance, and it is not easily deformed even when subjected to heating during evaporation or sputtering. Therefore, the reduction in the gas barrier properties of the gas barrier film due to deformation of the cured resin layer can also be avoided.

[0251] In the gas barrier layer obtained by modifying a layer containing a polymer compound (hereinafter sometimes referred to as the "polymer layer"), a silicon-containing polymer compound is preferred as the polymer compound used. Examples of silicon-containing polymer compounds include: polysilazane compounds, polycarbosilane compounds, polysilane compounds, and polyorganosiloxane compounds.

[0252] Among these, polysilazane compounds are preferred from the viewpoint of forming a barrier layer with excellent gas barrier properties. Examples of polysilazane compounds include inorganic polysilazanes and organic polysilazanes. Examples of inorganic polysilazanes include perhydropolysilazanes, and examples of organic polysilazanes include compounds in which some or all of the hydrogen atoms of perhydropolysilazanes are replaced by organic groups such as alkyl groups. Among these, inorganic polysilazanes are more preferred from the viewpoint of ease of acquisition and the ability to form a barrier layer with excellent gas barrier properties.

[0253] In addition, polysilazane compounds can also be used directly as commercially available products such as glass coating materials.

[0254] Polysilazane compounds can be used alone or in combination of two or more.

[0255] In addition to the aforementioned polymer compounds, the polymer layer may also contain other components, within the scope that does not impair the purpose of this invention. Examples of such other components include: curing agents, other polymers, antioxidants, light stabilizers, flame retardants, etc.

[0256] Examples of methods for forming a polymer layer include: using a spin coater, a doctor blade coater, a gravure coater, etc., to coat a layer-forming solution containing at least one polymer compound, other components used as needed, and a solvent onto a resin layer or a base layer formed on the resin layer as needed, and then appropriately drying the resulting coating film to form a polymer layer.

[0257] To dry the resulting coating or to improve the gas barrier properties of the gas barrier film, heating the coating is preferable. Commonly known heating and drying methods include hot air drying, hot roller drying, and infrared irradiation. The heating temperature is typically 80–150°C, and the heating time is typically tens of seconds to tens of minutes.

[0258] When forming a gas barrier layer, for example, when using a polysilazane compound as described above, the polysilazane undergoes a conversion reaction by heating after coating, thereby obtaining a coating with excellent gas barrier properties.

[0259] On the other hand, when a curing resin layer with low heat resistance is used, there is a concern that the cured resin layer may deform due to heating during the formation of such a coating. Deformation of the cured resin layer may adversely affect the gas barrier properties of the gas barrier film. However, in the cured resin layer of the gas barrier film according to the embodiments of the present invention, the heat resistance is excellent, so deformation is not easily caused even by heating during and after application. Therefore, the reduction in the gas barrier properties of the gas barrier film caused by deformation of the cured resin layer can also be avoided.

[0260] The thickness of the polymer layer is typically 20–1,000 nm, preferably 30–800 nm, and more preferably 40–400 nm.

[0261] Even if the thickness of the polymer layer is at the nanometer level, a gas barrier film with sufficient gas barrier properties can be obtained by performing modification treatments as described later.

[0262] Examples of modification treatments include ion implantation and vacuum ultraviolet irradiation. Among these, ion implantation is preferred for achieving high gas barrier properties. In ion implantation, the amount of ions implanted into the polymer layer can be appropriately determined based on the intended use of the formed gas barrier film (necessary gas barrier properties, transparency, etc.).

[0263] Examples of ions that can be implanted include: ions of rare gases such as argon, helium, neon, krypton, and xenon; ions of fluorocarbons, hydrogen, nitrogen, oxygen, carbon dioxide, chlorine, fluorine, and sulfur; ions of alkane gases such as methane, ethane, propane, butane, pentane, and hexane; ions of olefin gases such as ethylene, propylene, butene, and pentene; ions of alkane-dien gases such as pentadiene and butadiene; ions of alkynes such as acetylene and methylacetylene; ions of aromatic hydrocarbon gases such as benzene, toluene, xylene, indene, naphthalene, and phenanthrene; ions of cycloalkane gases such as cyclopropane and cyclohexane; ions of cycloolefin gases such as cyclopentene and cyclohexene; ions of conductive metals such as gold, silver, copper, platinum, nickel, palladium, chromium, titanium, molybdenum, niobium, tantalum, tungsten, and aluminum; ions of silanes (SiH4) or organosilicon compounds; and so on.

[0264] These ions can be used alone or in combination of two or more.

[0265] Among these, from the perspective of making injection easier and, in particular, obtaining a barrier layer with excellent barrier properties, at least one ion selected from hydrogen, nitrogen, oxygen, argon, helium, neon, xenon and krypton is preferred.

[0266] There are no particular limitations on the method of ion implantation, and examples include: irradiation of ions accelerated by an electric field (ion beam), and implantation of ions into plasma. Among these, the latter method of implanting plasma ions is preferred from the perspective of easily obtaining a membrane with gas barrier properties.

[0267] As for the types of ions used for plasma ion implantation, those that are the same as the ions exemplified above as the implanted ions can be listed.

[0268] The thickness of the implanted ion portion can be controlled by the type of ion, the applied voltage, the processing time, and other implantation conditions. It can be determined based on the thickness of the polymer layer and the purpose of the gas barrier membrane, and is usually 5 to 1000 nm.

[0269] The implantation of ions can be confirmed by elemental analysis at a distance of 10 nm from the surface of the polymer layer using X-ray photoelectron spectroscopy (XPS).

[0270] 4. Manufacturing methods for optical films

[0271] The manufacturing method for optical films according to embodiments of the present invention uses a process film and includes a first process, a second process, and a third process. This manufacturing method allows for the easy manufacture of the various optical films according to embodiments of the present invention. By including the first to third processes, thin optical films with excellent heat resistance and easily formed functional layers such as transparent conductive layers and gas barrier layers can be manufactured. Furthermore, by using a process film, optical films can be manufactured efficiently and easily.

[0272] • First step: A curable resin layer is formed on the process film using a curable resin composition containing polymer component (A) and curable monomer (B).

[0273] • Second step: At least a portion of the curable resin layer obtained in the first step is cured by irradiating it with at least one of an energy beam and an electron beam.

[0274] • Third step: After the second step begins, a cured resin layer is obtained by heat treatment that heats the above-mentioned curable resin layer to 150°C or higher.

[0275] Figure 3This is a process diagram illustrating an example of the manufacturing process of an optical film according to an embodiment of the present invention. Specifically, it is a cross-sectional schematic diagram, wherein... Figure 3 (a) Corresponding to the state before the formation of the cured resin layer, Figure 3 (b) Corresponding to the state after the first step described above, Figure 3 (c) The state corresponding to the second step described above. Figure 3 (d) corresponds to the state after the third process described above.

[0276] (First process)

[0277] First, a curable resin composition containing polymer component (A) and curable monomer (B) is used in the process film ( Figure 3 (a) symbol 1) forms a cured resin layer on its surface. Figure 3 (b) Symbol 2a). The preferred method for forming the curable resin layer is coating.

[0278] There are no particular limitations on the method of applying the curable resin composition to the process film; known coating methods such as spin coating, spray coating, bar coating, doctor blade coating, roller coating, doctor blade coating, mold coating, and gravure coating can be used. By applying the curable resin composition to the surface of the process film where the curable resin layer is to be formed, a uniform coating film can be easily obtained.

[0279] There are no particular limitations on the method for drying the obtained coating film; conventionally known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used. When a resin layer is formed by dissolving the polymer component (A) in a solvent without using the curing monomer (B), a phenomenon known as "skinning" easily occurs where the surface of the resin layer dries first, while the solvent remains inside the resin layer. As mentioned above, the curing resin layer according to the embodiments of the present invention preferably has a high Tg of the polymer component (A) contained in the curing resin composition used to form it. The above-mentioned skinning phenomenon is particularly prone to occur when the Tg of the polymer component (A) is high. However, by including the curing monomer (B) in the above-mentioned curing resin composition, the fluidity of the resin composition is maintained when drying the coating film obtained by solution casting, and the solvent can be effectively removed even to the interior of the resin layer.

[0280] The drying temperature of the coating is usually 30 to 150°C, preferably 50 to 100°C.

[0281] There is no particular limitation on the thickness of the dried coating (curing resin layer). Considering that it is basically no different from the thickness after curing, it can be set to be the same as the thickness of the resin layer mentioned above.

[0282] (Second process)

[0283] In the second step, at least a portion of the curable resin layer obtained in the first step is cured by irradiating it with at least one of an energy beam and an electron beam. Thus, Figure 3 (a) The cured resin layer 2a becomes Figure 3 (b) shows the cured resin layer 2b after being irradiated by energy rays or electron beams.

[0284] It is desired that energy rays or electron beams irradiate the entire surface of the cured resin layer.

[0285] Energy rays can be irradiated using high-pressure mercury lamps, electrodeless lamps, xenon lamps, etc.

[0286] The wavelength of the energy rays is preferably 200–400 nm, more preferably 350–400 nm. The irradiation dose is typically 50–1,000 mW / cm². 2 Light intensity 50–5,000 mJ / cm 2 Preferably, it is 1,000 to 5,000 mJ / cm². 2 The irradiation time is typically 0.1 to 1,000 seconds, preferably 1 to 500 seconds, and more preferably 10 to 100 seconds. Considering the heat load of the light irradiation process, multiple irradiations may be performed to meet the aforementioned light intensity.

[0287] In this case, to prevent the degradation of the polymer component (A) and the discoloration of the cured resin layer caused by energy ray irradiation, energy rays can be irradiated onto the curable resin composition via a filter that absorbs light of wavelengths unwanted by the curing reaction. According to this method, since the filter absorbs light of wavelengths unwanted by the curing reaction and that would cause degradation of the polymer component (A), the degradation of the polymer component (A) can be suppressed, and a colorless and transparent cured resin layer can be easily obtained.

[0288] As a filter, a resin membrane such as a polyethylene terephthalate (PET) membrane can be used. When using a resin membrane, it is preferable to perform a step between the first and second steps where a resin membrane, different from the membrane used in the first step, is laminated onto a curable resin layer. It should be noted that the resin membrane is typically peeled off after the second step.

[0289] The aforementioned resin film can also be considered a process film. By sandwiching the cured resin layer between the process film used in the first process and the resin film (second process film), a product can be obtained. Figure 1 (b) shows the optical film 10B.

[0290] Alternatively, the curable resin layer can be cured by irradiating it with an electron beam. In the case of electron beam irradiation, the curable resin layer can usually be cured without the use of a photopolymerization initiator. An electron beam accelerator or similar device can be used in the case of electron beam irradiation. The irradiation dose is typically in the range of 10 to 1,000 krad. The irradiation time is typically 0.1 to 1,000 seconds, preferably 1 to 500 seconds, and more preferably 10 to 100 seconds.

[0291] The curing of the curable resin layer can be carried out in an inert gas atmosphere such as nitrogen, as needed. Curing in an inert gas atmosphere easily avoids interference from oxygen, moisture, and other factors that may hinder the curing process.

[0292] (Third process)

[0293] In the third step, after the second step begins, a heat treatment is performed to heat the curable resin layer to above 150°C to obtain the cured resin layer. Figure 3 (d) symbol 2).

[0294] The third process essentially completes the curing of the curable resin layer, thus forming a cured resin layer.

[0295] In the third step, from the viewpoint of further promoting curing, the heat treatment temperature is preferably 160°C or higher, more preferably 170°C or higher, and even more preferably 180°C or higher. In addition, from the viewpoint of suppressing the deformation of the obtained cured resin layer, it is preferably 210°C or lower, more preferably 200°C or lower, and even more preferably 190°C or lower.

[0296] The heat treatment time varies depending on the type of curable resin composition used and the heat treatment temperature. From the viewpoint of ensuring sufficient curing, it is preferably 30 minutes or more, more preferably 45 minutes or more, and even more preferably 1 hour or more. From the viewpoint of productivity, it is preferably 3 hours or less, more preferably 2.5 hours or less, and even more preferably 2 hours or less.

[0297] Heat treatment can be started after the second process described above. For example, heat treatment can be performed after the second process is completed, or it can be performed in parallel with the second process after a certain period of time has elapsed since the second process began.

[0298] There are no particular restrictions on the heat treatment method; various methods can be used, such as heating ovens, autoclaves, or heating the curing resin layer in an atmosphere or inert gas atmosphere.

[0299] Example

[0300] The invention will now be described in more detail by way of examples, but the invention is not limited by these examples.

[0301] The determination and evaluation of the physical properties of the cured resin layer and optical film of each embodiment and comparative example were carried out in the following order.

[0302] <Peak temperature of loss tangent and rate of decrease in storage modulus>

[0303] The polyethylene terephthalate (PET) films on both sides of the cured resin layer, which corresponds to the process film, were peeled off. Eight such cured resin layers were stacked to form a laminate with a thickness of 40 μm. Next, test pieces of 5 mm × 30 mm were cut, and the laminate of the cured resin layers was held using a thermomechanical analyzer (NETZSCH Japan Inc. DMA242) with a clamping distance of 15 mm. The laminate of the cured resin layers was then heated from 25 °C to 280 °C at a rate of 3 °C / min, and the storage modulus and loss modulus were measured. Then, a loss tangent (loss modulus / storage modulus) curve was plotted over the temperature range of 25 °C to 280 °C. The curve was then peak-separated using a Gaussian function as the fitting function, and the temperature of each peak was taken as the loss tangent peak temperature.

[0304] In addition, the reduction rate of energy storage modulus from 25°C to 150°C is calculated using the following formula (1) and is taken as the energy storage modulus reduction rate.

[0305] Energy storage modulus reduction rate = (energy storage modulus at 25℃ - energy storage modulus at 150℃) ÷ energy storage modulus at 25℃ × 100 (%) ... Equation (1)

[0306] <Total Light Transmittance>

[0307] As optical properties of the film, the total light transmittance was measured in the following order.

[0308] The polyethylene terephthalate (PET) films on both sides of the cured resin layer, which is equivalent to the process film, are peeled off. The resulting cured resin layer is used as a test piece. The transmittance of white light passing through the test piece is measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., NDH5000), and this is taken as the total light transmittance (%).

[0309] [Example 1]

[0310] A curable resin composition E1 for forming a curable resin layer was prepared in the following order.

[0311] As a polymer component, 100 parts by mass of polyimide resin (PI) granules (manufactured by Kawamura Sangyo Co., Ltd., product name KPI-MX300F, Tg = 354°C, weight average molecular weight 280,000) were dissolved in methyl ethyl ketone (MEK) to prepare a 15% by mass solution of PI. Next, 122 parts by mass of tricyclodecanediethanol diacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-DCP) as the curing monomer (B) and 5 parts by mass of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by BASF, Irgacure 819) as the polymerization initiator were added to this solution and mixed to prepare a curable resin composition E1. It should be noted that the curing monomer (B) and polymerization initiator used in this example and other experimental examples are solvent-free and are all 100% solid raw materials.

[0312] Next, a first PET film (manufactured by Toyobo Co., Ltd., CosmoshinePET100A-4160, 100μm thick) with an easy-to-adhere layer on one side was used as the first process film. A curable resin composition E1 was coated on the side of the PET film opposite to the easy-to-adhere layer, and the coating was dried by heating at 90°C for 3 minutes.

[0313] Furthermore, a second PET film (manufactured by Toyobo Co., Ltd., Cosmoshine PET50A-4160, 50μm thick), having an easy-to-adhere layer on one side, is laminated onto the dried coating film with the opposite side facing the easy-to-adhere side. Then, using a belt conveyor type ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd., product name: ECS-401GX) and a high-pressure mercury lamp (manufactured by Eye Graphics Co., Ltd., product name: H04-L41), an illuminance of 400mW / cm is achieved at a lamp height of 100mm, an output power of 3kW, and a wavelength of 365nm. 2 The light intensity is 800 mJ / cm 2 Under the conditions of (using an ultraviolet photometer UV-351 manufactured by ORC Manufacturing Co., Ltd.), ultraviolet light was applied through a second PET film to carry out a curing reaction, forming a cured resin layer with a thickness of 5μm.

[0314] Furthermore, the cured resin layer was heat-treated by heating it at 180°C for 1 hour in a heating oven, thereby obtaining an optical film.

[0315] [Comparative Example 1]

[0316] Except that the cured resin layer was not subjected to heat treatment at 180°C for 1 hour, an optical film was obtained in the same manner as in Example 1.

[0317] [Comparative Example 2]

[0318] An optical film was obtained in the same manner as in Example 1, except that polysulfone resin granules (manufactured by BASF, ULTRASON S3010, Tg = 180°C) were used instead of polyimide resin (PI) granules.

[0319] The measurement results of the examples and comparative examples are shown in Table 1. It should be noted that in the heat treatment column of Table 1, "Y" indicates that heat treatment was performed and "N" indicates that no heat treatment was performed.

[0320] [Table 1]

[0321]

[0322] As shown in Table 1, in the optical film of Example 1, only a loss tangent peak with a peak temperature of 250°C was observed. That is, the optical film of Example 1 has more than one loss tangent peak, and the peak temperature of all loss tangent peaks is 150°C or higher. Therefore, the optical film of Example 1 can be a film with a small reduction rate in storage modulus.

[0323] On the other hand, in the film of Comparative Example 1, loss tangent peaks with peak temperatures of 130°C, 190°C, and 250°C were observed. That is, although the film of Comparative Example 1 has more than one loss tangent peak, not all loss tangent peaks have a peak temperature of 150°C or higher. Therefore, compared with the optical film of Example 1, the reduction rate of storage modulus is large. Therefore, the film of Comparative Example 1 undergoes a large degree of deformation under thermal action, which can be understood as leaving room for improvement when used in the formation of functional layers that require heating in the formation process of transparent conductive layers, gas barrier layers, etc.

[0324] Furthermore, in Comparative Example 2, a polysulfone resin with a Tg of 180°C was used as the polymer component (A), and the reduction rate of storage modulus was greater compared to the optical film of Example 1. Therefore, the film of Comparative Example 2 exhibits a greater degree of deformation under thermal action, which can be understood as indicating potential for improvement in the formation of functional layers that require heating during the formation process of transparent conductive layers, gas barrier layers, etc.

Claims

1. An optical film comprising a processing film and a cured resin layer, The cured resin layer is a layer formed from the cured product of a curable resin composition, the curable resin composition containing a polymer component (A) and a curable monomer (B), and the thickness of the cured resin layer is less than 15 μm. The characteristic values ​​obtained from the dynamic viscoelasticity measurement of the optical film, which is heated from 25°C to 280°C at a heating rate of 3°C / second, satisfy the following (I) and (II). (I) In the curve representing the change of loss tangent relative to temperature, there is more than one loss tangent peak, and the peak temperature of all loss tangent peaks is above 150℃. (II) The energy storage modulus reduction rate calculated by the following formula (1) is less than 40%, where the energy storage modulus reduction rate is the rate of reduction of the energy storage modulus from 25°C to 150°C. Energy storage modulus reduction rate = (energy storage modulus at 25℃ - energy storage modulus at 150℃) ÷ energy storage modulus at 25℃ × 100 (%) ··· Equation (1).

2. An optical film comprising a processing film and a cured resin layer, The cured resin layer is a layer formed from the cured product of a curable resin composition, the curable resin composition containing a polymer component (A) and a curable monomer (B), the thickness of the cured resin layer being less than 15 μm, and the glass transition temperature of the polymer component (A) being greater than 250°C. In the dynamic viscoelasticity measurement of the optical film, which was performed by heating from 25°C to 280°C at a heating rate of 3°C / second, the curve representing the change of the loss tangent relative to temperature showed that there was more than one loss tangent peak, and the peak temperature of all loss tangent peaks was above 150°C.

3. The optical film according to claim 1 or 2, wherein, The thickness of the cured resin layer is less than 12 μm.

4. A method for manufacturing an optical film, the method comprising: In the first step, a curable resin layer is formed on the process film. The curable resin layer is formed from a curable resin composition containing a polymer component (A) and a curable monomer (B). The second step involves irradiating the curable resin layer with at least one of an energy beam and an electron beam, thereby curing at least a portion of the curable resin layer. as well as The third step involves heating the curable resin layer to above 150°C after the second step begins, thereby obtaining a cured resin layer with a thickness of less than 15 μm.

5. A transparent conductive film, comprising: The optical film according to any one of claims 1 to 3, and the transparent conductive layer disposed on the cured resin layer of the optical film.

6. A gas barrier membrane, comprising: The optical film according to any one of claims 1 to 3, and the gas barrier layer disposed on the cured resin layer of the optical film.

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