Laminated film and display device

Abstract

The present invention addresses the problem of providing a laminated film and a display device that are resistant to peeling from a substrate and capable of suppressing optical unevenness.　This laminated film is characterized by including a base material film, an adhesive layer, and a cured layer in this order, wherein the base material film contains at least one of a cycloolefin-based resin and a cellulose ester-based resin, the adhesive layer contains a (meth)acrylate, a hardness HA of the adhesive layer and a hardness HB of the base material film, calculated by a nanoindentation method, satisfy formula (1) and formula (2), respectively, and a surface of the cured layer opposite to the adhesive-layer side has a fine uneven structure.　Formula (1): 0.26≤HA≤0.50 [GPa] Formula (2): 0.20≤HB≤0.36 [GPa]

Description

Laminated films and display devices

[0001] The present invention relates to laminated films and display devices. More specifically, it relates to laminated films, etc., that are less prone to peeling from the substrate and can suppress optical unevenness.

[0002] In recent years, various techniques have been attempted to improve light extraction technology in the processes for manufacturing laminated films using the roll-to-roll method. For example, the technology disclosed in Patent Document 1 discloses a light extraction film for improving light extraction technology, but there is still room for improvement in the technology related to this film.

[0003] Japanese Patent Publication No. 2017-84821

[0004] For example, consider a laminated film having a base material, an adhesive layer, and a cured layer in that order. Hereafter, the "material used to form the cured layer" will be abbreviated as "curable material".

[0005] When forming a cured layer, the curable material is cured by light and / or heat, and simultaneously shrinks. At this time, the substrate and the cured layer are in close contact via an adhesive layer. However, if the adhesive layer cannot keep up with the shrinkage of the curable material during curing, poor adhesion will occur between the substrate and the cured layer. Therefore, in order for the adhesive layer to keep up with such shrinkage, it is preferable for the adhesive layer to be soft.

[0006] Furthermore, in response to recent demands for increased productivity, the transport speed of the substrate in the above process has been increased. However, in order to suppress quality defects caused by an imbalance between the formation speed of the hardened layer that adheres to the substrate via the adhesive layer and the transport speed of the substrate, it is preferable for the adhesive layer to be soft.

[0007] However, if the adhesive layer is too soft compared to the hardness of the cured layer, the transport tension during the manufacturing process of the laminated film is disrupted. This can cause twists and wrinkles in the substrate and cured layer, which can remain as faulty areas within the surface of the laminated film. These faulty areas then contribute to optical inconsistencies in the manufactured laminated film.

[0008] This invention has been made in view of the above-mentioned problems and circumstances, and its objective is to provide a laminated film and a display device that are less prone to peeling from the substrate and can suppress optical unevenness.

[0009] In order to solve the above problems, the inventors investigated the causes of the above problems and found that the above problems can be solved by controlling the hardness of the adhesive layer and the hardness of the base film, calculated by the nanoindentation method, within a certain range, leading to the present invention. That is, the above problems according to the present invention are solved by the following means.

[0010] 1. A laminated film comprising a base film, an adhesive layer, and a cured layer in this order, wherein the base film contains at least one of a cycloolefin resin or a cellulose ester resin, the adhesive layer contains (meth)acrylate, the hardness HA of the adhesive layer and the hardness HB of the base film, calculated by nanoindentation, satisfy the following formulas (1) and (2), and the surface of the cured layer opposite to the adhesive layer has a fine uneven structure. Formula (1) 0.26 ≤ HA ≤ 0.50 [GPa] Formula (2) 0.20 ≤ HB ≤ 0.36 [GPa]

[0011] 2. The laminated film according to paragraph 1, characterized in that the base film contains a cycloolefin resin.

[0012] 3. The laminated film according to claim 1, characterized in that the hardness HA of the adhesive layer, calculated by nanoindentation, is in the range of 0.34 to 0.40 GPa.

[0013] 4. The laminated film according to claim 1, characterized in that the thickness of the base film is in the range of 10 to 45 μm, and the thickness of the adhesive layer is in the range of 400 to 2000 nm.

[0014] 5. The laminated film according to paragraph 1, characterized in that the thickness of the base film is in the range of 10 to 45 μm, and the thickness of the adhesive layer is in the range of 600 to 1000 nm.

[0015] 6. The laminated film according to paragraph 1, characterized in that, when the adhesive layer is the first adhesive layer, a second adhesive layer is provided on the surface opposite to the first adhesive layer, sandwiching the base film.

[0016] 7. The laminated film according to paragraph 1, characterized in that it comprises a carrier film, a base film, an adhesive layer, and a cured layer in this order.

[0017] 8. The laminated film according to paragraph 7, characterized in that a second adhesive layer is provided between the carrier film and the base film.

[0018] 9. An organic EL or inorganic EL display device characterized by comprising a laminated film as described in any one of paragraphs 1 to 8.

[0019] The above means of the present invention makes it possible to provide a laminated film and a display device that are less prone to peeling from the substrate and can suppress optical unevenness. The mechanism by which the effects of the present invention are manifested or the mechanism of action are not yet clear, but are inferred to be as follows.

[0020] The laminated film of the present invention is a laminated film comprising a base film, an adhesive layer, and a cured layer in this order, wherein the base film contains at least one of a cycloolefin resin or a cellulose ester resin, the adhesive layer contains (meth)acrylate, the hardness HA of the adhesive layer and the hardness HB of the base film, calculated by nanoindentation, satisfy formulas (1) and (2), and the surface of the cured layer on the side opposite to the adhesive layer has a fine uneven structure.

[0021] As mentioned above, conventional technologies still have room for improvement in the manufacturing process of laminated films, and there is a need to improve problems such as poor adhesion due to shrinkage when curing curable materials, and twisting and wrinkling due to high transport speeds.

[0022] In the present invention, the hardness of the adhesive layer is defined as the hardness calculated by the nanoindentation method, and this is kept within the range of the formula (1), and the hardness of the base film is kept within the range of the formula (2), so that the adhesive layer can follow the shrinkage of the base film. It is presumed that this makes it difficult for peeling from the base material to occur and optical unevenness can be suppressed.

[0023] An example of a diagram showing the flow of hardness calculation by the nanoindentation method An example of a load-displacement curve obtained from the hardness calculated by the nanoindentation method An example of a schematic diagram showing the relationship between the indentation depth ht and the contact depth hc for the measurement target An example of a schematic diagram showing the relationship between the contact projection area A of the indenter and the contact depth hc An example of a flowchart showing the flow of the manufacturing process of the base film by the solution casting method An example of a schematic diagram of an apparatus for manufacturing the base film by the solution casting method A schematic diagram for explaining the state in which the film is stretched by the stretching apparatus An example of a schematic diagram for explaining the process of imparting a shape to the cured layer An example of a schematic configuration diagram of a laminated film having a configuration of a carrier film / base film / adhesive layer / cured layer An example of a schematic configuration diagram of a laminated film having a configuration of a carrier film / second adhesive layer / base film / first adhesive layer / cured layer A classification table of test results for peel evaluation

[0024] The laminated film of the present invention is a laminated film including a base film, an adhesive layer, and a cured layer in this order, wherein the base film contains at least one of a cycloolefin resin or a cellulose ester resin, and the adhesive layer contains (meth)acrylate, and the hardness HA of the adhesive layer and the hardness HB of the base film calculated by the nanoindentation method satisfy the formula (1) and the formula (2), and the surface of the cured layer on the side opposite to the adhesive layer side has a fine uneven structure. This feature is a common or corresponding technical feature in each of the following embodiments (aspects).

[0025] Hereinafter, the present invention, its components, and the forms and aspects for implementing the present invention will be described in detail. In the present application, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value.

[0026] While the advantages and features provided by one or more embodiments of the present invention will be better understood from the following detailed description and accompanying drawings, these drawings are for illustrative purposes only and are not intended to define any limitations of the present invention.

[0027] [I. Laminated Film] The laminated film of the present invention is a laminated film comprising a base film, an adhesive layer, and a cured layer in this order, wherein the base film contains at least one of a cycloolefin resin or a cellulose ester resin, the adhesive layer contains (meth)acrylate, the hardness HA of the adhesive layer and the hardness HB of the base film, calculated by nanoindentation, satisfy the following formulas (1) and (2), and the surface of the cured layer on the side opposite to the adhesive layer has a fine uneven structure. Formula (1) 0.26 ≤ HA ≤ 0.50 [GPa] Formula (2) 0.20 ≤ HB ≤ 0.36 [GPa]

[0028] 1. Base film (1.1) Components of the base film The base film according to the present invention contains at least one of the following as components: a thermoplastic resin, which is either a cycloolefin resin (cyclic olefin resin) or a cellulose ester resin.

[0029] By containing either a cycloolefin resin or a cellulose ester resin in the base film, it is possible to easily control the stretchability and degree of crystallinity, and ensure good adhesion. The base film may also be subjected to surface modification treatment after manufacturing.

[0030] Furthermore, the base film may contain thermoplastic resins other than the cycloolefin resin or cellulose ester resin mentioned above, and may also contain plasticizers and other optional components as additives.

[0031] (Cycloolefin resins) Examples of cycloolefin resins include (co)polymers having a structure represented by the following general formula (1).

[0032]

[0033] In the above general formula (1), R １ ~R ４ are each independently a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, a silyl group or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, a hydroxy group, an ester group, an alkoxy group, a cyano group, an amide group, an imide group, or a silyl group). However, R １ ~R ４ may be bonded to each other in two or more to form an unsaturated bond, a monocyclic or polycyclic ring, and this monocyclic or polycyclic ring may have a double bond or form an aromatic ring. R １ and R ２ or R ３ and R ４ may form an alkylidene group. p and m are integers of 0 or more.

[0034] In the above general formula (1), R １ and R ３ are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 or 2 carbon atoms. R ２ and R ４ are a hydrogen atom or a monovalent organic group, and at least one of R ２ and R ４ represents a polar group having polarity other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, p is an integer of 0 to 3, more preferably m + p = 0 to 4, further preferably 0 to 2, and particularly preferably m = 1, p = 0. A specific monomer having m = 1 and p = 0 is preferable in that the resulting cycloolefin-based resin has a high glass transition temperature and excellent mechanical strength.

[0035] Examples of polar groups in the above-mentioned specific monomers include carboxyl groups, hydroxyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, amino groups, amide groups, and cyano groups, and these polar groups may be bonded via linking groups such as methylene groups. Also, hydrocarbon groups to which polar divalent organic groups such as carbonyl groups, ether groups, silyl ether groups, thioether groups, and imino groups are bonded via linking groups can also be listed as polar groups. Among these, carboxyl groups, hydroxyl groups, alkoxycarbonyl groups, or aryloxycarbonyl groups are preferred, and alkoxycarbonyl groups or aryloxycarbonyl groups are particularly preferred.

[0036] Furthermore, R ２ and R ４ At least one of them is equation - (CH ２ ) ｎ Monomers that are polar groups represented by COOR are preferred because the resulting cycloolefin resin has a high glass transition temperature, low hygroscopicity, and excellent adhesion to various materials. In the above formula for a specific polar group, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4, and particularly preferably 1 to 2 carbon atoms, and preferably an alkyl group.

[0037] Examples of copolymerizable monomers include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. The number of carbon atoms in the cycloolefin is preferably in the range of 4 to 20, and more preferably 5 to 12.

[0038] In this embodiment, the cycloolefin resin can be used alone or in combination of two or more types.

[0039] The preferred molecular weight of the cycloolefin resin in this embodiment is the intrinsic viscosity [η] ｉｎｈThe concentration is preferably 0.2 to 5 dl / g, more preferably 0.3 to 3 dl / g, and particularly preferably 0.4 to 1.5 dl / g. The number-average molecular weight (Mn) in polystyrene terms, as measured by gel permeation chromatography (GPC), is preferably 8,000 to 100,000, more preferably 10,000 to 80,000, and particularly preferably 12,000 to 50,000. The weight-average molecular weight (Mw) is preferably in the range of 20,000 to 300,000, more preferably 30,000 to 250,000, and particularly preferably 40,000 to 200,000.

[0040] Intrinsic viscosity [η] ｉｎｈ By having the number-average molecular weight and weight-average molecular weight within the above range, the heat resistance, water resistance, chemical resistance, and mechanical properties of the cycloolefin resin, as well as the moldability of the cycloolefin film of this embodiment, are improved.

[0041] The glass transition temperature (Tg) of the cycloolefin resin in this embodiment is typically within the range of 110°C or higher, preferably 110 to 350°C, more preferably 120 to 250°C, and particularly preferably 120 to 220°C.

[0042] A Tg of 110°C or higher is preferable because it makes deformation less likely to occur under high-temperature conditions or during secondary processing such as coating or printing. On the other hand, setting the Tg to 350°C or lower avoids difficulties in molding and suppresses the possibility of resin degradation due to heat during molding.

[0043] (Cellulose ester resin) In the present invention, "cellulose ester" refers to a cellulose acylate resin in which some or all of the hydrogen atoms of the hydroxyl groups (-OH) at positions 2, 3, and 6 in the glucose units that are linked by β-1,4 bonds and constitute cellulose are replaced with acyl groups.

[0044] The cellulose ester is not particularly limited, but is preferably an ester of a linear or branched carboxylic acid having, for example, 2 to 22 carbon atoms. The carboxylic acid constituting the ester may be an aliphatic carboxylic acid or a ring-containing aromatic carboxylic acid.

[0045] Examples of cellulose esters include cellulose esters in which the hydrogen atoms of the hydroxyl group portion of cellulose are substituted with acyl groups having 2 to 22 carbon atoms, such as acetyl groups, propionyl groups, butyryl groups, isobutyryl groups, valeryl groups, pivaloyl groups, hexanoyl groups, octanoyl groups, lauroyl groups, and stearoyl groups.

[0046] The carboxylic acid (acyl group) constituting the ester may have substituents. The carboxylic acid constituting the ester is preferably a lower fatty acid having 6 or fewer carbon atoms, and more preferably a lower fatty acid having 3 or fewer carbon atoms. The acyl group in the cellulose ester may be a single type or a combination of multiple acyl groups.

[0047] Specific examples of cellulose esters include cellulose acetates such as diacetylcellulose (DAC) and triacetylcellulose (TAC). Other examples include mixed fatty acid esters of cellulose in which propionate groups or butyrate groups are bonded in addition to acetyl groups, such as cellulose acetate propionate (CAP), cellulose acetate butyrate, and cellulose acetate propionate butyrate. These may be contained individually or in combination of two or more.

[0048] (Other components) The base film may contain other components to the extent that they do not impair the effects of this embodiment. For example, it may contain specific hydrocarbon resins described in Japanese Patent Publication No. 9-221577 and Japanese Patent Publication No. 10-287732, or known thermoplastic resins, thermoplastic elastomers, rubber polymers, organic fine particles, inorganic fine particles, etc. It may also contain additives such as specific wavelength dispersants, sugar ester compounds, antioxidants, release accelerators, rubber particles, plasticizers, and ultraviolet absorbers.

[0049] Furthermore, commercially available cycloolefin resins can preferably be used. Commercially available products include, for example, those sold by JSR Corporation under the trade names Arton® G, Arton® F, Arton® R, and Arton® RX, and those sold by Nippon Zeon Co., Ltd. under the trade names Zeonor® ZF14, ZF16, Zeonex® 250, or Zeonex® 280, which can be used.

[0050] (1.2) Hardness and Thickness of the Substrate Film The hardness HB of the substrate film according to the present invention is a hardness calculated by the nanoindentation method and satisfies the following formula (2). Formula (2) 0.20 ≤ HB ≤ 0.36 [GPa]

[0051] Furthermore, it is more preferable, from the viewpoint of achieving the effects of the present invention, that the hardness HB is within the range of 0.20 to 0.31.

[0052] The hardness HB of the above-mentioned substrate film can be calculated using the nanoindentation method, for example, as follows.

[0053] Nanoindentation is a method that evaluates hardness solely through calculations based on physical quantities (load and indentation depth) measured by a device. It determines stiffness S (contact stiffness) and contact depth (hc), and then calculates hardness and Young's modulus.

[0054] The measurement of hardness and Young's modulus by nanoindentation is standardized as the instrumented indentation test, an international standard ISO 14577. In this application, hardness was adopted.

[0055] Figure 1 is an example of a diagram illustrating the flow of hardness calculation using the nanoindentation method. In Figure 1, "A" is the contact point between the indenter and the sample, "B" is the point where the maximum load is reached, "C" is the point where unloading begins, "D" is the point where drift measurement begins, and "E" is the end point of the test.

[0056] Figure 2 shows an example of a load-displacement curve obtained from hardness calculated by nanoindentation. In Figure 2, "P" is the load, "h" is the displacement, "ht" is the indentation depth, and "hc" is the contact depth.

[0057] By controlling the load and measuring the displacement in the manner shown in Figure 1, a load-displacement curve like the one in Figure 2 is obtained. From the slope of the unloading curve, the stiffness S is calculated. Using this stiffness S, the contact depth hc is calculated using the following formula.

[0058]

[0059] In this application, a Berkovich indenter was used, so the constant ε = 0.75 in the above formula relates to the indenter shape.

[0060] Figure 3 is an example of a schematic diagram showing the relationship between the indentation depth ht and the contact depth hc relative to the object being measured.

[0061] Since the base film and adhesive layer undergo elastic deformation when the indenter is pressed into them, the relationship between the measured indentation depth ht and the contact depth hc, which is the area that supports the load, is as shown in Figure 3. It is assumed that the plastic deformation portion of the object being measured comes into contact with the indenter, while the elastic deformation portion does not.

[0062] Figure 4 is an example of a schematic diagram showing the relationship between the contact projection area A of the indenter and the contact depth hc. The contact projection area A of the indenter can be calculated from the contact depth hc using the following formula.

[0063] A = 24.56 hc ２

[0064] Also, hardness H ＩＴ The average pressure that the object being measured can withstand is given by the following formula. In the following formula, "P" is the pressure applied to the object being measured.

[0065] H ＩＴ = P / A

[0066] This nanoindentation method allows for highly accurate measurements with a displacement resolution of 0.01 nm using a head assembly with an ultra-low load, for example, a maximum load of 40 μN and a load resolution of 1 nN. Furthermore, from the perspective of improving accuracy, nanoindenters that operate within a scanning electron microscope have also been developed, and these can be applied to determine the hardness HB of the above-mentioned substrate film.

[0067] Furthermore, the thickness of the base film is preferably in the range of 10 to 45 μm from the viewpoint of improving rigidity, maintaining shape, and ease of manufacturing in long lengths. If the thickness of the base film is 10 μm or more, the rigidity increases and it becomes easier to maintain the shape. Also, if the thickness of the base film is 45 μm or less, the mass does not increase excessively, making it easier to manufacture long lengths of base film. Moreover, the thickness of the base film is more preferably 15 to 30 μm from the viewpoint of achieving the effects of the present invention.

[0068] The thickness of the base film can be measured, for example, by the method described in JIS B 7502 using a micrometer. Specifically, the thickness of the base film is measured at 10 random locations. Then, the arithmetic mean of the 10 measured values ​​is calculated, and this arithmetic mean is taken as the thickness of the base film.

[0069] (1.3) Method for manufacturing the base film The base film according to the present invention can be manufactured by a solution casting method or a melt casting method.

[0070] The "solution casting method" is a method in which a dope is cast onto a moving support to form a cast film (web), which is then dried to a degree that allows it to be peeled off. After that, the film is peeled off from the support, and the peeled film is dried and stretched while being transported by conveyor rollers to produce a long resin film.

[0071] The "melt casting method" is a method in which a composition containing a thermoplastic resin and additives is heated and melted to a temperature at which it exhibits fluidity, and then the molten material containing the fluid thermoplastic resin is cast. Molding methods involving heating and melting can be further classified into molten extrusion, press molding, inflation molding, injection molding, blow molding, and stretch molding. Among these molding methods, molten extrusion is preferred in terms of mechanical strength and surface accuracy.

[0072] The following describes an example of the process by which the base film according to the present invention is produced by the solution casting method.

[0073] The manufacturing process for the base film according to the present invention consists of a raw film manufacturing process and a raw film processing process.

[0074] (1.3.1) Raw material film manufacturing process The raw material film manufacturing process consists of at least three steps, (A), (B), and (C) below.

[0075] (A) A step of preparing a dope and casting it onto a support to form a web. (B) A step of performing the first stage of stretching. (C) A step of drying the web and winding up the formed film.

[0076] Furthermore, the processing of the raw film consists of at least the following step (D).

[0077] (D) The process of transporting the wound raw film and performing the second stage of stretching.

[0078] Furthermore, in step (D) above, the amount of residual solvent immediately before the second stage of stretching relative to the winding width is in the range of 0.1 to 0.5% by mass.

[0079] Figure 5 is a flowchart showing the process of manufacturing a base film by solution casting, and Figure 6 is an example of a schematic diagram of an apparatus for manufacturing a base film by solution casting.

[0080] (A) The process of casting the dope onto a support to form a web The process of casting the dope onto a support to form a web consists of at least (A-1) a dope preparation step, (A-2) a casting step, and (A-3) a peeling step.

[0081] (A-1) Dope Preparation Process In the dope preparation process, at least the resin and solvent are stirred in the stirring tank 1a of the stirring device 1 to prepare the dope to be cast onto the support 3 (endless belt). The following description assumes that the dope contains a cycloolefin resin, but the dope may also contain a cellulose ester resin. In the following description, "cycloolefin resin" will also be simply referred to as "COP".

[0082] This process involves dissolving the COP in a solvent, primarily a solvent suitable for COP, while stirring in a dissolution vessel to form a dope. In some cases, the COP may be mixed with other compounds in the dissolution vessel to prepare the dope, which is the main dissolving solution.

[0083] The concentration of COP in the dope is preferably high from the viewpoint of reducing the drying load after casting the dope onto the support, but if it is too high, the load during filtration increases and the accuracy deteriorates. Therefore, from the viewpoint of balancing reduced drying load and deterioration of accuracy due to increased load during filtration, the concentration of COP in the dope is preferably in the range of 10 to 35% by mass, and more preferably in the range of 15 to 30% by mass.

[0084] The above solvents may be used individually or in combination of two or more. However, from the viewpoint of production efficiency, it is preferable to use a mixture of a good solvent and a poor solvent for COP, and from the viewpoint of COP solubility, it is preferable to have a higher proportion of the good solvent. Furthermore, it is preferable that the dope contains water in the range of 0.01 to 2.00% by mass. The mixing ratio of the good solvent to the poor solvent is preferably in the range of 70 to 98% by mass for the good solvent and in the range of 2 to 30% by mass for the poor solvent.

[0085] In this specification, a "good solvent" is defined as one that dissolves the COP (Cellulose Opticulum) used on its own. A "poor solvent" is defined as one that swells or does not dissolve the COP on its own. Therefore, whether a solvent is good or poor may depend on the type and number of substituents on the COP. There are no particular limitations on good solvents, but examples include organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate. Among these, methylene chloride or methyl acetate are particularly preferred. There are no particular limitations on poor solvents, but examples include methanol, ethanol, n-butanol, cyclohexane, and cyclohexanone, which are preferably used.

[0086] As the solvent mentioned above, the solvent removed from the base film by drying during the manufacturing process of the base film may be recovered and reused. The recovered solvent may contain trace amounts of additives such as plasticizers, UV absorbers, polymers, and monomer components, but it can still be reused even if these are present. If necessary, it can also be purified and reused.

[0087] For dissolving COP during dope preparation, general methods can be used. Specifically, methods performed at atmospheric pressure, below the boiling point of the main solvent, and under pressure above the boiling point of the main solvent are preferred. Furthermore, heating above the boiling point at atmospheric pressure can be achieved by combining heating and pressurization. Cooling dissolution is also preferably used, which allows COP to be dissolved in a solvent such as methyl acetate.

[0088] Furthermore, a method of dissolving by stirring while heating at a temperature above the boiling point of the solvent at atmospheric pressure, but within a range where the solvent does not boil under pressure, is also preferred, as this prevents the formation of gels or lumpy undissolved matter called "mamako." Another preferred method is to mix COP with a poor solvent to wet or swell it, and then add a good solvent to dissolve it.

[0089] Pressurization may be performed by injecting an inert gas such as nitrogen gas or by increasing the vapor pressure of the solvent through heating. The pressure is adjusted so that the solvent does not boil at the set temperature. Heating is preferably performed from an external source, and jacket-type heaters are preferred for their ease of temperature control. When heating with the solvent added, a higher temperature is preferable from the viewpoint of COP solubility, but if the heating temperature is too high, the required pressure increases and productivity decreases. Therefore, the heating temperature is preferably in the range of 30 to 120°C, more preferably in the range of 60 to 110°C, and even more preferably in the range of 70 to 105°C.

[0090] While dope filtration can be performed by conventional methods, a method of filtration while heating at a temperature above the boiling point of the solvent at atmospheric pressure, but within a range where the solvent does not boil under pressure, is preferred from the viewpoint of minimizing the increase in the difference in filtration pressure (called differential pressure) before and after filtration. The temperature at this time is preferably in the range of 30 to 120°C, more preferably in the range of 45 to 70°C, and even more preferably in the range of 45 to 55°C. A low filtration pressure is preferable. Specifically, a filtration pressure of 1.6 MPa or less is preferred, more preferably 1.2 MPa or less, and even more preferably 1.0 MPa or less.

[0091] It is preferable to filter the dope during or after dissolution using a suitable filter material such as filter paper. Hereinafter, "dope during or after dissolution" will also be simply referred to as "COP solution." From the viewpoint of removing insoluble matter, it is preferable to use a filter material with low absolute filtration accuracy. However, a filter material with too low absolute filtration accuracy is prone to clogging during filtration. Therefore, it is preferable that the absolute filtration accuracy of the filter material be 0.008 mm or less, more preferably in the range of 0.001 to 0.008 mm, and even more preferably in the range of 0.003 to 0.006 mm.

[0092] There are no particular restrictions on the material of the filter material mentioned above, and ordinary filter materials can be used. From the viewpoint of eliminating fiber shedding, for example, plastic filter materials such as polypropylene and Teflon (registered trademark), or metal filter materials such as stainless steel are preferred.

[0093] It is preferable to remove or reduce impurities, particularly bright spot foreign matter, contained in the COP of the raw material by filtration. "Bright spot foreign matter" refers to points (foreign matter) that appear when light leaks from the opposite side when light is shone from one polarizing plate side while a film or the like is placed between two polarizing plates in a crossed nicol state and observed from the other polarizing plate side. The diameter of the bright spot foreign matter is preferably 0.01 mm or larger, and it is preferable to have as few bright spots smaller than 0.01 mm as possible.

[0094] The number of bright spots is 200 per cm. ２ The following is preferable. A more preferable number of bright spots is 100 / cm². ２ The following is more preferably 50 pieces / cm ２ The following is more preferably 0 to 10 pieces / cm ２ The following applies:

[0095] (A-2) Casting process In the casting process, the transport speed V １ The web 5, formed by doping cast onto the support 3, is heated on the support 3. This evaporates the solvent until the web 5 can be peeled off the support 3 by the peeling roller 4, thereby controlling the amount of residual solvent just before the first stage of stretching.

[0096] The support 3 is preferably one with a mirror-finished surface, and a stainless steel belt or a drum with a plated surface made of casting is preferably used. The support 3 is made of, for example, a stainless steel belt and is held by a pair of rollers 3a and 3b and a plurality of rollers located between them. One or both of the rollers 3a and 3b are provided with a drive device that applies tension to the support 3, so that the support 3 is used in a taut state. The support 3 may also be a drum.

[0097] The surface temperature of the support 3 is preferably high from the viewpoint of enabling a fast drying rate of the web, and is preferably within the range of -50°C to the boiling point of the solvent. The surface temperature of the support is more preferably in the range of 0 to 55°C, and even more preferably in the range of 22 to 50°C.

[0098] There are no particular limitations on the method for controlling the surface temperature of the support 3, but examples include blowing hot or cold air onto it, and bringing hot water into contact with the back of the support. Among these, bringing hot water into contact with the back of the support is preferred because heat transfer is efficient and the time it takes for the support temperature to become constant is short. When using the method of blowing hot air, it is possible to use air at a temperature higher than the target temperature.

[0099] In the casting process, the dope prepared in the dope preparation process is delivered to the casting die 2 via a conduit through a pressurized metering gear pump or the like. The dope is then cast from the casting die 2 to the casting position on a support 3 made of an endlessly rotating stainless steel belt.

[0100] Casting dies include coat hanger dies and T-dies, and any of these are preferred. To increase the film formation speed of the raw film, two or more of the above-mentioned casting dies may be provided on the support, and the dope amount may be divided and layered. It is also preferable to obtain a laminated raw film by a co-casting method in which multiple dopes are cast simultaneously.

[0101] The casting die is equipped with a mechanism for adjusting the width of the slit through which the dope is discharged (or extruded in the case of molten resin). The direction of dope discharge from the casting die 2 to the support 3 is adjusted by the inclination of the casting die 2. At this time, the inclination of the casting die 2 should be appropriately set so that the angle with respect to the normal of the surface of the support 3 (the surface to which the dope is cast) is within the range of 0 to 90°.

[0102] Here, the point where the dope exits the casting die slit is called the lip, and a casting die is preferred in which the slit shape of the lip portion can be adjusted, making it easier to ensure a uniform thickness of the dope during discharge. In the casting process, "web" refers to the doped film cast from the lip portion mentioned above.

[0103] It is preferable to use the heat bolts of the casting die to adjust the gap between the width of the slits through which the dope is discharged, thereby controlling the initial discharge thickness of the cast film (web) by adjusting the film thickness deviation immediately after discharge to within a range of 1.0 to 5.0% of the entire cast film (web).

[0104] From the viewpoint of improving productivity, the casting width (also called "cast width") is preferably 1.3 m or more, and more preferably within the range of 1.3 to 4.0 m. If the casting width does not exceed 4.0 m, stripes will not form during the manufacturing process, and stability in the subsequent transport process will be improved. Furthermore, from the viewpoint of transportability and productivity, the casting width is preferably within the range of 1.3 to 3.0 m.

[0105] (A-3) Peeling Process In the peeling process, the solvent is evaporated on the support 3 in the casting process until the web 5 has sufficient film strength to be peeled off, and then the web is dried and solidified or cooled and solidified. The web is then peeled off the support 3 before the original film completes one full rotation around the support 3. In other words, this process involves peeling off the web, which has had the solvent evaporated on the support 3 until it has sufficient film strength to be peeled off, at the peeling position using a peeling roller 4 while maintaining its self-supporting properties. The roller that assists in peeling the web off the support is called a peeling roller.

[0106] The time required for peeling is preferably in the range of 30 to 600 seconds, from the viewpoint of surface quality, moisture permeability, and peelability. The temperature at the peeling site on the support is preferably in the range of -50 to 40°C, more preferably in the range of 10 to 40°C, and most preferably in the range of 15 to 30°C.

[0107] <Amount of Residual Solvent> The amount of residual solvent immediately before the first stretching stage is adjusted as appropriate depending on the intensity of the drying conditions, the length of the support 3, etc. As a method for controlling this amount of residual solvent, it is preferable to carry out the evaporation in an atmosphere within the range of 5 to 75°C. Methods for evaporating the solvent include, for example, applying hot air to the top surface of the web, transferring heat from the back surface of the support 3 using a liquid, and transferring heat from both sides by radiant heat. Among these, the method of transferring heat from both sides by radiant heat is preferred from the viewpoint of improving drying efficiency. Methods combining these are also preferably used.

[0108] Depending on the thickness of the web, if the amount of residual solvent at the delamination point (the position where the web is separated from the support) is too high, the web may become too soft and difficult to delaminate. This can impair flatness and cause horizontal stripes, twists, and vertical streaks due to delamination tension. Conversely, if the amount of residual solvent is too low, a portion of the web may peel off midway through the process. To ensure the web exhibits good flatness, the amount of residual solvent is preferably in the range of 1 to 50% by mass, and more preferably in the range of 1 to 15% by mass, from the perspective of balancing economic speed and quality.

[0109] The film deposition rate can be increased by using a gel casting method, which involves peeling off the web while the amount of residual solvent contained in the web is as high as possible. This allows the web to gel on the support, strengthening the film and accelerating peeling, thereby increasing the film deposition rate. Examples of such methods include adding a poor solvent relative to COP during doping and gelling the web after doping and casting; gelling the web by cooling the support and peeling it off while it contains a large amount of residual solvent; and adding a metal salt during doping.

[0110] The amount of residual solvent is defined by the following formula: Amount of residual solvent (mass%) = {(M - N) / N} × 100 In the above formula, M is the mass of a sample taken at any point during or after the manufacture of the web or base film, and N is the mass of M after heating at 115°C for 1 hour.

[0111] The amount of residual solvent can be measured by headspace gas chromatography. This measurement involves sealing the sample in a container, heating it, and then rapidly injecting the gas from the container into a gas chromatograph while simultaneously identifying the compounds using mass spectrometry and quantifying the volatile components. Gas chromatography allows for the observation of all peaks of the volatile components, and by using analytical methods that utilize electromagnetic interactions, highly accurate quantification of volatile substances and monomers can also be performed.

[0112] <Peeling Tension> The peeling tension when separating the support from the web is preferably 300 N / m or less. More preferably, it is in the range of 196 to 245 N / m, but if wrinkles are likely to form during peeling, it is preferable to peel with a tension of 190 N / m or less.

[0113] (B) First-stage stretching process The first-stage stretching process is a process in which the web is stretched in the first stage relative to the web width immediately after casting. In this process, the web, after being peeled from the support, is stretched in the transport direction (Machine Direction, hereinafter also referred to as the "MD direction"). In this case, the web shrinks in the width direction (Traverse Direction, hereinafter also referred to as the "TD direction") perpendicular to the MD direction within the web surface.

[0114] Methods for shrinking the web include, for example, (1) treating the web at a high temperature without maintaining its width to increase its density, (2) applying tension to the web in the transport direction (MD direction) to shrink the web in the width direction (TD direction), and (3) drastically reducing the amount of residual solvent in the web.

[0115] Stretching may be performed according to the required optical properties, and it is preferable to stretch in at least one direction, although it may also be stretched in two mutually orthogonal directions. For example, biaxial stretching may be performed in the width direction of the film (TD direction) and the transport direction (MD direction) perpendicular to it. When performing biaxial stretching, it is preferable to set the stretching ratio in each of the TD and MD directions to be within the range of 1.1 to 2.0 times. The stretching ratio is defined as (stretched size of the film after stretching) / (stretched size of the film before stretching).

[0116] <Amount of Residual Solvent> In the present invention, the amount of residual solvent immediately before the first stretching stage is the same as the amount of residual solvent at the peeling point of the peeling step described above. From the viewpoint of improving the adhesion of the film and suppressing deterioration of the film strength, it is preferable that the amount of residual solvent immediately before the first stretching stage is in the range of 1 to 15% by mass, and the stretching ratio is in the range of 1.1 to 2.0 times.

[0117] (C) Process of winding up the film formed by drying the web The process of winding up the film formed by drying the web consists of (C-1) drying process, (C-2) first cutting process, and (C-3) winding process. Note that the dope transport speed V in the dope preparation process １ The winding speed in the first winding process described above is the same speed. Furthermore, "the same speed" for the conveying speed and the winding speed means, strictly speaking, that they are the same within a range of ±10%.

[0118] (C-1) Drying process The drying process involves heating the web on a support and evaporating the solvent. Inside the drying apparatus 7, the web is transported by multiple transport rollers arranged in a staggered pattern when viewed from the side, and the web is dried in the process.

[0119] There are no particular restrictions on the drying method in the drying apparatus 7. Generally, the web is dried using hot air, infrared rays, heated rollers, microwaves, etc. However, for simplicity, drying the web with hot air is preferred. Combining these methods is also preferred. The drying process may be performed as needed.

[0120] Thinner webs dry faster, but excessively rapid drying can easily impair the flatness of the finished film.

[0121] When drying at high temperatures, the amount of residual solvent must be considered, but by keeping the amount of residual solvent below a certain level, failure due to solvent foaming can be prevented. Drying is generally carried out within the range of 30 to 250°C throughout the process. It is particularly preferable to dry within the range of 35 to 200°C, and it is preferable to increase the drying temperature in stages. The temperature of the support may be the same throughout or may vary depending on the location.

[0122] In the web drying process, roller drying methods are generally employed, that is, a method in which the web is alternately passed through a number of rollers arranged vertically and horizontally to dry it, or a tenter method in which the web is transported and dried. When a tenter stretching device is used for drying the web, it is preferable to use a device that allows the gripping length of the web (the distance from the start of gripping to the end of gripping) to be independently controlled on the left and right sides by the left and right gripping means of the tenter stretching device in the stretching process described later. It is also preferable to provide a neutral zone between different temperature zones so that each zone does not interfere with the other.

[0123] (C-2) First Cutting Process In the first cutting process, the cutting section 8, which consists of a slitter, cuts both ends of the film F in the width direction after it has been stretched in the first stretching process and dried. The portion of the film F that remains after the ends have been cut constitutes the product portion that becomes the film product. On the other hand, the portion cut from the film F may be recovered and reused again as part of the raw materials to produce the base film.

[0124] (C-3) First winding process In the first winding process, the film F is transported at a transport speed V １ (Winding speed V １ The film is then wound up by the winding device 9, completing the process of producing the raw film roll. The preferred range for the initial tension when winding the film F in the winding process is within the range of 20 to 300 N / m.

[0125] (1.3.2) Processing process of the raw film roll (D) Second stage stretching process The processing process of the raw film roll involves transporting the wound film and (D) performing the second stage stretching. Furthermore, the processing process of the raw film roll consists of (D-1) unwinding the raw film roll, (D-2) stretching the raw film roll, and (D-3) winding up the stretched film. In detail, the processing process involves unwinding the wound film from its roll body and then transporting it at a transport speed V ２ This process involves transporting the material and performing a second stage of stretching. It consists of at least a feeding process, a second stage of stretching, a second cutting process, and a second winding process.

[0126] In the second stretching step of the wound film, the amount of residual solvent immediately before the second stretching step is in the range of 0.1 to 0.5% by mass relative to the winding width.

[0127] (D-1) Raw film unwinding process In the raw film unwinding process, the wound film is unwinded from the roll and transported at a speed V ２ It will be transported by [means of transport].

[0128] <Amount of residual solvent> Subsequently, the above film is subjected to a second stretching stage. At this time, the amount of residual solvent immediately before the second stretching stage is in the range of 0.1 to 0.5% by mass.

[0129] (D-2) Process of stretching the raw film In the process of stretching the raw film, the transport speed V ２ The film F, which has been transported, is stretched by the stretching device 10.

[0130] As for stretching methods, methods that stretch the film in the transport direction (longitudinal direction of the film; film formation direction; casting direction; MD direction) by creating a difference in peripheral speed of rollers, or the tenter method that stretches the film in the width direction (direction perpendicular to the film plane; TD direction) by fixing both side edges of the film with clips or the like, are preferred in order to improve the performance, productivity, flatness, and dimensional stability of the film.

[0131] Furthermore, in the case of the so-called tenter method, driving the clip portion with a linear drive system is preferable because it allows for smooth stretching and reduces the risk of breakage. These width maintenance or lateral stretching in the film formation process are preferably performed by a tenter stretching device, which may be either a pin tenter or a clip tenter. In addition to stretching, drying may also be performed within the stretching device 10.

[0132] The second stretching step may involve stretching the film only in the MD direction within the film plane, stretching only in the TD direction, stretching in both the MD and TD directions, or stretching in an oblique direction. There are no limitations on the stretching direction, but from the viewpoint of obtaining a wide film, it is preferable to include a step that includes stretching in at least the width direction. Such stretching can be performed using the stretching device 10.

[0133] <Amount of residual solvent> The amount of residual solvent in the film during stretching is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0134] <Tenter stretching device> Figure 7 is a schematic diagram illustrating how the film is stretched by the stretching device. In Figure 7, a tenter stretching device is used as the stretching device.

[0135] As shown in Figure 7, the stretching device 10 is mainly divided into a width-holding zone A, a stretching zone B, a film width-holding zone C, and a stress-relaxing zone D. A description of each zone is as follows.

[0136] - Width holding zone A: A zone where the distance between gripping clips of the film width (both ends of the base) is constant from the entrance of the stretching device 10 to the stretching start point a of the film. - Stretching zone B: A zone where the distance between gripping clips of the film width (both ends of the base) widens in the direction of travel (conveying direction) from the stretching start point a to the stretching end point b of the film stretching device 10. - Film width holding zone C: A zone that holds the film width in the stretched state, where the distance between gripping clips of the stretched film width (both ends of the base) is constant from the stretching end point b of the film stretching device 10 to the stress relaxation processing start point c of the film. - Stress relaxation zone D: A zone where the distance between gripping clips of the film width (both ends of the base) narrows in the direction of travel (conveying direction) from the stress relaxation processing start point c to the stress relaxation processing end point d of the film stretching device 10.

[0137] The "relaxation process" mentioned above refers to a gripping pattern that narrows the film width in the direction of travel (conveyor direction, longitudinal direction, MD direction). The relaxation process is a process that prevents the film F from being stretched taut in the width direction, that is, a process that does not apply stress in the width direction of the film, and this relaxation process is performed while gripping the film edge.

[0138] The a, b, c, and d shown between each zone can be summarized as follows:

[0139] a. Starting point of film stretching, entrance to the stretching zone b. Ending point of film stretching, entrance to the film width retention zone c. Starting point c of stress relaxation treatment on the film, entrance to the stress relaxation zone d. Ending point of stress relaxation treatment, exit to the stress relaxation zone

[0140] Furthermore, the symbols in Figure 7 are as follows: F Film Hc Film width at the entrance of the stress relaxation zone Hd Film width at the exit of the stress relaxation zone 110 Housing 111 Clip 112 Rail "Hd".

[0141] <Other> In the second stretching step, the film F may be dried in the same manner as in the first drying step, if necessary. There are no particular restrictions on the drying method at this time, and generally hot air, infrared rays, heated rollers, and microwaves can be used. Among these drying methods, drying the film F with hot air is preferred due to its simplicity.

[0142] (D-3) The process of winding up the stretched film consists of a second cutting step and a second winding step.

[0143] (D-3-1) Second Cutting Process In the second cutting process, a cutting unit 11 consisting of a slitter cuts both ends of the film F in the width direction, which has been stretched in the second stretching process. The portion of the film F remaining after the ends have been cut constitutes the product portion that becomes the film product. On the other hand, the portion cut from the film F may be recovered and reused again as part of the raw materials for film making.

[0144] (D-3-2) Second winding process In the second winding process, the film F is transported at a transport speed V ２ The film is then wound up by the winding device 12. It is preferable to wind up while attaching a protective film. The thickness of the film is preferably in the range of 5 to 100 μm, more preferably in the range of 5 to 80 μm, and even more preferably in the range of 5 to 40 μm. The preferred range for the initial tension when winding the film F in the second winding step is in the range of 20 to 300 N / m.

[0145] The winding method for film F can be done using a commonly used winder, and there are various methods for controlling the tension, such as the constant torque method, constant tension method, tapered tension method, and programmed tension control method with constant internal stress, which can be used as appropriate.

[0146] Before winding, the ends of the film may be slit and trimmed to the desired product width, and a surface modification treatment may be applied to both ends of the film to prevent sticking and scratching during winding.

[0147] <Amount of Residual Solvent> The amount of residual solvent in the film during the second winding process is 2% by mass or less. It is preferable that the amount of residual solvent at this stage be 0.4% by mass or less, from the viewpoint of obtaining a film with good dimensional stability, and it is even more preferable that the amount of residual solvent be within the range of 0.00 to 0.20% by mass.

[0148] 2. Adhesive Layer (2.1) Components of the Adhesive Layer The adhesive layer according to the present invention contains acrylate or a crosslinked product thereof. The adhesive layer may also contain resins other than the acrylate, inorganic particles, organic particles, and other components as needed.

[0149] ((meth)acrylate) The "(meth)acrylate" according to the present invention includes polymer acrylates, polyfunctional (meth)acrylates, and monofunctional (meth)acrylates, and at least one of these is used. In addition, a polyfunctional acrylate represented by the following structural formula (1) can also be used.

[0150] Polymer acrylates refer to polymers that have reactive (meth)acrylate groups in their side chains. Examples of polymer acrylates include acrylic acrylates that have (meth)acrylate groups as side chains in a (meth)acrylic polymer main chain, and specifically, ART CURE manufactured by Negami Kogyo Co., Ltd.

[0151] Other examples include polyester acrylates in which (meth)acrylate is substituted at the polyester ends, specifically M6100, M6500, M7100, M8100, etc., manufactured by Toagosei Co., Ltd.

[0152] In this specification, the molecular weight Mw of "polymer acrylate" is 1000 or more. Since the control of hardness shown in this invention is easily achieved by utilizing polymer acrylate, it is preferable to include polymer acrylate.

[0153]

[0154] In the above structural formula (1), X represents a monovalent to hexavalent hydrocarbon group having an aromatic structure containing a heteroatom selected from the group consisting of a monovalent to hexavalent aliphatic hydrocarbon group, a monovalent to hexavalent aliphatic cyclic hydrocarbon group, a monovalent to hexavalent hydrocarbon group having an aromatic structure, a nitrogen atom, an oxygen atom, and a sulfur atom, or a heterocyclic aliphatic hydrocarbon group containing a nitrogen atom, an oxygen atom, and a sulfur atom as heteroatoms, and R １ , R ２ , R ３ Each of these is independently either a hydrogen atom or a methyl group, where n is an integer in the range of 0 to 8 and m is an integer in the range of 1 to 6.

[0155] There are no particular restrictions on the polyfunctional (meth)acrylate, and various known ones can be used. Examples include polyfunctional (meth)acrylates having two or more polymerizable double bonds in one molecule, such as 1,2-ethanediol diacrylate, 1,2-propanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, tris(2-acryloyloxy) isocyanurate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, di(trimethylolpropane) tetraacrylate, di(pentaerythritol) pentaacrylate, and di(pentaerythritol) hexaacrylate.

[0156] Examples of monofunctional (meth)acrylates include hydroxyl group-containing (meth)acrylic acid esters, carboxyl group-containing vinyl monomers, sulfonic acid group-containing vinyl monomers, acidic phosphate ester-based vinyl monomers, and vinyl monomers having methylol groups. One or more of these can be used.

[0157] Examples of hydroxyl group-containing (meth)acrylic acid esters include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylate (e.g., "Praxel" manufactured by Daicel Chemical Industries, Ltd.), mono(meth)acrylate of polyester diols obtained from phthalic acid and propylene glycol, mono(meth)acrylate of polyester diols obtained from succinic acid and propylene glycol, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, and (meth)acrylic acid adducts of various epoxy esters.

[0158] Examples of carboxyl group-containing vinyl monomers include (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

[0159] Examples of sulfonic acid group-containing vinyl monomers include vinyl sulfonic acid, styrene sulfonic acid, and sulfoethyl (meth)acrylate.

[0160] Examples of acidic phosphate ester vinyl monomers include 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloropropyl acid phosphate, and 2-methacryloyloxyethylphenyl phosphate.

[0161] Examples of vinyl monomers having a methylol group include N-methylol(meth)acrylamide.

[0162] (Resins other than acrylates) Examples of resins other than acrylates include polyolefins, polyurethanes, polyesters, polyvinylidene chloride, modified silicone polymers, and styrene-butadiene rubber. These resins may be used individually or in combination of two or more.

[0163] (Inorganic particles and organic particles) The adhesive layer according to the present invention contains inorganic particles or organic particles, and can impart slipperiness and antiblocking properties to the laminated film from the viewpoint of film transportability and winding properties.

[0164] Examples of inorganic particles include fine particles of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, and calcium carbonate. Specifically, silicon dioxide particles are preferred (for example, Nippon Shokubai Co., Ltd.'s "Sea Hostar Series" KE-P20, KE-P30, etc.).

[0165] The average particle size of the inorganic particles described above may be, for example, in the range of 20 to 500 nm, preferably in the range of 50 to 400 nm. Within this range, both transparency and antiblocking properties can be achieved.

[0166] Examples of organic particles include acrylic resin particles, styrene resin particles, polyester resin particles, polyurethane resin particles, polycarbonate resin particles, polyamide resin particles, silicone resin particles, and fluoropolymer resin particles. Also included are copolymer resin particles of two or more monomers used in the synthesis of these resins.

[0167] The average particle size of the organic particles can be, for example, in the range of 20 to 500 nm, preferably in the range of 30 to 300 nm. Within this range, both transparency and antiblocking properties can be achieved.

[0168] (Crosslinking agent) The above resin is preferably crosslinked with a crosslinking agent. Examples of crosslinking agents include oxazoline compounds, carbodiimide compounds, isocyanate compounds, and epoxy compounds. If the above resin is a polyolefin, it is more preferable that the crosslinked product of the polyolefin is a crosslinked product of an acid-modified polyolefin. "Crosslinked product of an acid-modified polyolefin" refers to a crosslinked product of a composition containing an acid-modified polyolefin and a crosslinking agent.

[0169] Oxazoline compounds can be compounds having two or more oxazoline groups in their molecule. Examples of commercially available oxazoline compounds include the Epocross® series (manufactured by Nippon Shokubai Co., Ltd.), such as K-2010E, K-2020E, K-2035E, WS-300, WS-500, and WS-700.

[0170] Carbodiimide compounds can be compounds having two or more carbodiimide groups in their molecule. Examples of carbodiimide compounds include those manufactured by Nisshinbo Chemical Co., Ltd., under the trade name "Carbodilite Series" V-02, V-02-L2, SV-02, V-04, and E-02.

[0171] An isocyanate compound is a compound containing two or more isocyanate groups in one molecule, and may be an aliphatic isocyanate, an aromatic isocyanate, or an alicyclic isocyanate. Examples of isocyanate compounds include hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate. Furthermore, the isocyanate compound may be masked with a blocking agent.

[0172] As the epoxy compound, a compound having one or more epoxy groups in its molecule is used. Alternatively, if a polymer (epoxy resin) having two or more epoxy groups in its molecule is used, a compound having two or more functional groups that react with epoxy groups in its molecule may be used in combination.

[0173] Here, "functional groups that react with epoxy groups" include, for example, carboxyl groups, phenolic hydroxyl groups, mercapto groups, and primary or secondary aromatic amino groups. It is particularly preferable that there are two or more of these functional groups in a single molecule, taking into consideration three-dimensional curability. Examples of polymers having one or more epoxy groups in their molecule include epoxy resins.

[0174] Examples of epoxy resins include bisphenol A type epoxy resins derived from bisphenol A and epichlorohydrin, bisphenol F type epoxy resins derived from bisphenol F and epichlorohydrin, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolac type epoxy resins, alicyclic epoxy resins, diphenyl ether type epoxy resins, hydroquinone type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, fluorene type epoxy resins, polyfunctional epoxy resins such as trifunctional and tetrafunctional epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated.

[0175] Examples of commercially available epoxy resins include, but are not limited to, the following. Furthermore, two or more of these epoxy resins may be used in combination.

[0176] Examples of commercially available products from Japan Epoxy Resin Co., Ltd. include JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, and YX4000.

[0177] Examples of commercially available products from DIC Corporation include Epiclon 830, EXA835LV, HP4032D, and HP820.

[0178] Examples of commercially available products manufactured by ADEKA Corporation include the EP4100 series, EP4000 series, and EPU series.

[0179] Examples of commercially available products from Daicel Chemical Corporation include the Celoxide series (2021, 2021P, 2083, 2085, 3000, etc.), the Epolid series, and the EHPE series.

[0180] Examples of commercially available products from Nippon Steel Chemical Co., Ltd. include the YD series, YDF series, YDCN series, YDB series, and phenoxy resins. Among these, phenoxy resins include polyhydroxy polyethers synthesized from bisphenols and epichlorohydrin, which have epoxy groups at both ends (YP series), etc.

[0181] Examples of commercially available products from Nagase ChemteX include the Denacol series.

[0182] Examples of commercially available products manufactured by Kyoeisha Chemical Co., Ltd. include the Epolite series.

[0183] (Other Components) The adhesive layer according to the present invention may further contain other components as needed. Examples of other components include leveling agents, polymerization initiators, polymerization accelerators, viscosity modifiers, slip agents, dispersants, plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, flame retardants, colorants, antistatic agents, compatibilizers, and the like.

[0184] (2.2) Hardness and Thickness of the Adhesive Layer The hardness HA of the adhesive layer according to the present invention is a hardness calculated by the nanoindentation method and satisfies the following formula (1). Formula (1) 0.26 ≤ HA ≤ 0.50 [GPa]

[0185] The hardness HA mentioned above is preferably in the range of 0.35 to 0.45 GPa, from the viewpoint of maintaining adhesion between the adhesive layer and the substrate, and between the adhesive layer and the cured layer.

[0186] The hardness HA of the adhesive layer, obtained by the nanoindentation method, can be calculated in the same way as the hardness HB of the substrate film described above.

[0187] Furthermore, while the thickness of the adhesive layer is not particularly limited, it is preferably in the range of 400 to 2000 nm, and more preferably in the range of 600 to 1000 nm, from the viewpoint of maintaining adhesion between the adhesive layer and the substrate, and between the adhesive layer and the cured layer.

[0188] The thickness of the adhesive layer can be measured, for example, by the method described in JIS B 7502 using a micrometer. Specifically, the thickness of the adhesive layer is measured at 10 random locations. Then, the arithmetic mean of the 10 measured values ​​is calculated, and this arithmetic mean is taken as the thickness of the adhesive layer.

[0189] (2.3) Method for forming the adhesive layer The adhesive layer according to the present invention is formed by applying (coating) an adhesive layer forming composition to the surface of a base film, and then drying, heating, or irradiating with light depending on the type of composition.

[0190] When the laminated film of the present invention includes a carrier film, the "adhesive layer" formed between the carrier film and the base film is conveniently referred to as the "second adhesive layer." Furthermore, the "adhesive layer" formed between the base film and the cured layer is conveniently referred to as the "first adhesive layer."

[0191] In an embodiment of the present invention, the laminated film of the present invention may not include a carrier film, and adhesive layers may be formed on both the front and back surfaces of the base film. In this case, in the laminated film of the present invention comprising a base film, an adhesive layer, and a curing layer in this order, if the adhesive layer is designated as the first adhesive layer, the laminated film will have a second adhesive layer on the surface opposite to the first adhesive layer, with the base film in between.

[0192] The following describes a method for forming an adhesive layer, using the case where the laminated film of the present invention does not contain a carrier film as an example.

[0193] The adhesive layer-forming composition used when forming the adhesive layer according to the present invention may be a solution obtained by dispersing or dissolving the aforementioned inorganic particles, organic particles, resin, crosslinking agent, and other components in a solvent (e.g., water).

[0194] The total solid content concentration of the adhesive layer-forming composition can be determined by the type of components, solubility, coating viscosity, wettability, and thickness after coating. To obtain an adhesive layer with high surface uniformity, the total solid content concentration is preferably in the range of 1 to 100 parts by mass, more preferably in the range of 1 to 50 parts by mass, per 100 parts by mass of solvent.

[0195] The viscosity of the adhesive layer-forming composition can be any appropriate viscosity within the coatable range. Preferably, the viscosity measured at a shear rate of 1000 [1 / s] at 23°C is in the range of 1 to 50 [mPa·sec], and more preferably in the range of 2 to 10 [mPa·sec]. Within this range, an adhesive layer with excellent surface uniformity can be formed.

[0196] The adhesive layer-forming composition can be prepared by any method. For example, a commercially available solution or dispersion may be used, or a solvent may be added to a commercially available solution or dispersion, or solid components may be dissolved or dispersed in various solvents.

[0197] Any method may be used to apply (coat) the adhesive layer-forming composition; for example, methods using gravure printing or die coating can be used. When applying the adhesive layer to the substrate film, pretreatment to improve wettability may be performed on the surface of the substrate film, such as solvent modification, corona treatment, and plasma treatment.

[0198] 3. Cured Layer The cured layer according to the present invention is formed to adhere closely to the substrate film via an adhesive layer. The surface of the cured layer opposite to the adhesive layer that does not adhere to it is formed to have a fine uneven structure.

[0199] (3.1) Components of the cured layer The cured layer according to the present invention may contain, in addition to the and binder resin, other additives, etc., to the extent that they do not impair the functions thereof.

[0200] (Binder resin) There are no particular restrictions on the binder resin that can be included in the cured layer, but examples include thermoplastic resins, thermosetting resins, and photocurable resins.

[0201] From the viewpoint of increasing surface hardness, it is preferable that the binder resin is a polymer or copolymer of a thermopolymerizable monomer or a photopolymerizable monomer. Among these, a polymer of a photopolymerizable monomer is more preferable.

[0202] Suitable thermoplastic resins include, for example, cellulose ester resins such as triacetylcellulose, cellulose acetate propionate, and diacetylcellulose. Other suitable resins include cyclic olefin resins such as cycloolefin resins, polypropylene resins such as polypropylene, acrylic resins such as polymethyl methacrylate, and polyester resins such as polyethylene terephthalate.

[0203] Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In addition to curing by heat, thermosetting resins may also be cured by using a curing agent.

[0204] The compounds constituting the photocurable resin (photopolymerizable resin) are not particularly limited, but photopolymerizable monomers, oligomers, and polymers can be used. Examples of monofunctional photopolymerizable monomers include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone. Examples of bifunctional or multifunctional photopolymerizable monomers include polymethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and compounds obtained by modifying these compounds with ethylene oxide, polyethylene oxide, etc.

[0205] Furthermore, these compounds may have their refractive index adjusted to a high level by introducing aromatic rings, halogen atoms other than fluorine, sulfur, nitrogen, phosphorus atoms, etc.

[0206] Furthermore, in addition to the above compounds, resins composed of relatively low molecular weight monomers having unsaturated double bonds can also be used. Examples of such resins include polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiol polyene resins.

[0207] When polymerizing (crosslinking) photopolymerizable monomers, polymerization initiators may be used. Polymerization initiators are components that decompose upon light irradiation, generating radicals that initiate or advance the polymerization (crosslinking) of photopolymerizable compounds.

[0208] (Other Additives) In addition to the binder resin described above, the cured layer according to the present invention may contain other additives, etc., to the extent that they do not impair the functions of the binder resin. Examples of other additives include conventionally known dispersants, surfactants, antistatic agents, silane coupling agents, thickeners, color inhibitors, colorants (pigments, dyes), defoamers, leveling agents, flame retardants, ultraviolet absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, lubrication agents, etc.

[0209] (3.2) Surface shape and thickness of the cured layer The cured layer according to the present invention has a surface shape that allows light to be extracted from the device in a manner that increases the emitted light and reduces loss when used in combination with organic EL (also referred to as OLED) and other self-emissive light sources. That is, the surface shape of the cured layer on the side opposite the adhesive layer is a fine uneven structure.

[0210] The "fine uneven structure" formed in the hardened layer in the present invention is, for example, a sinusoidal structure with an aspect ratio of about 1 and a period in the range of 0.5 to 10 μm.

[0211] The above-mentioned fine surface irregularities can be observed, for example, using a laser microscope. For example, a Keyence laser microscope VK-X1000 can be used.

[0212] The surface shape of the hardened layer according to the present invention may include fine particles for refractive index adjustment in the hardened layer forming composition prepared during the formation of the hardened layer, as described later, but the creation of the aforementioned sinusoidal structure is shaped by a mold. Therefore, the manufacturing process does not require highly difficult processes such as the production of beads with precisely controlled shapes and dimensions, which are difficult at the nanoscale, or monolayer coating without aggregation.

[0213] (3.3) Method for forming the hardened layer The hardened layer according to the present invention can be formed by, for example, the following method.

[0214] First, a composition for forming a cured layer is prepared by dissolving a binder resin and other photopolymerizable compounds such as additives in a suitable solvent.

[0215] The above-mentioned hardened layer-forming composition is then applied to a mold with a microstructure on its surface, such as a gravure roll, and brought into contact with a film on which an adhesive layer has been formed. The hardened layer-forming composition is then irradiated with light such as ultraviolet light. The photopolymerizable compound is polymerized (crosslinked), and the hardened layer-forming composition is cured to form a hardened layer.

[0216] As a method for applying the hardened layer-forming composition to the mold, known application methods can be used. Examples of known application methods include spin coating, dip method, spray method, slide coating method, bar coating method, roll coating method, gravure coating method, and die coating method.

[0217] There are no particular restrictions on the light used to cure the hardened layer-forming composition, but examples include ultraviolet light and electron beams. When using ultraviolet light, ultraviolet light emitted from ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc., can be used. Furthermore, ultraviolet light with a wavelength range of 190 to 380 nm can be used. Specific examples of electron sources include Cockcroftwald type, Van de Graft type, resonant transformer type, insulated core transformer type, or various electron beam accelerators such as linear type, dynamitron type, and high-frequency type.

[0218] Furthermore, polymerization initiators may be added to the above-mentioned hardened layer-forming composition as needed. Other additives may also be included depending on the purpose of increasing the hardness of the hardened layer, suppressing curing shrinkage, and controlling the refractive index.

[0219] The polymerization initiator is not particularly limited as long as it can release a substance that initiates radical polymerization upon light irradiation, and known substances can be used. Specific examples of known substances include acetophenones, benzophenones, Michler-benzoyl benzoate, α-amyloxime esters, thioxanthones, propiophenones, benzyls, benzoins, and acylphosphine oxides. It is also preferable to use a mixture of the polymerization initiator and a photosensitizer, specifically, n-butylamine, triethylamine, and poly-n-butylphosphine. When the binder resin contained in the cured layer is a resin system having radically polymerizable unsaturated groups, it is preferable to use acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc., individually or in combination as the polymerization initiator.

[0220] The method for imparting shape to the hardened layer according to the present invention can be, for example, the method described in Japanese Patent Application Publication No. 05-169015.

[0221] Figure 8 is an example of a schematic diagram illustrating the process of shaping the cured layer. The surface of the cured layer according to the present invention, on the side opposite the adhesive layer, has a fine uneven structure. An example of the process of shaping the surface of the cured layer according to the present invention, on the side opposite the adhesive layer, will be explained. In Figure 8, it is assumed that the cured layer according to the present invention has already been formed on "film F". In Figure 8, the arrows on each roller indicate the rotation direction of each roller. In addition, although Figure 8 omits the illustration of the film supply device that feeds out film F and the winding device that winds up the film with the fine uneven structure formed on it, these may be provided.

[0222] Although not shown in the diagram, the curable resin liquid Raq may be applied directly to the film F instead of onto the recessed plate roller 20, and then the coating surface on the film F may be pressed against the recessed plate roller 20 with the pressure roller 40 to impart shape to the cured layer.

[0223] (Preparation of curable resin solution) First, prepare the curable resin solution Raq. As the curable resin solution Raq, a composition can be used which is an appropriate mixture of prepolymers, oligomers and / or monomers having polymerizable unsaturated bonds or epoxy groups in the molecule.

[0224] Examples of the prepolymers and oligomers include unsaturated polyesters such as condensates of unsaturated dicarboxylic acids and polyvalent alcohols, epoxy resins, methacrylates such as polyester methacrylate, polyether methacrylate, polyol methacrylate, and melamine methacrylate, and acrylates such as polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, and melamine acrylate.

[0225] Examples of monomers include acrylic acid esters, methacrylic acid esters, substituted amino alcohol esters of unsaturated acids, unsaturated carboxylic acid amides, and polyfunctional compounds.

[0226] Examples of acrylic acid esters include styrene monomers such as styrene and α-methylstyrene, methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, and butyl acrylate.

[0227] Examples of methacrylate esters include methyl methacrylate, ethyl methacrylate, methoxyethyl methacrylate, and ethoxymethyl methacrylate.

[0228] Examples of substituted amino alcohol esters of unsaturated acids include 2-(N,N-diethylamino)ethyl acrylate.

[0229] Examples of unsaturated carboxylic acid amides include acrylamide and methacrylamide.

[0230] Examples of polyfunctional compounds include dipropylene glycol diacrylate, ethylene glycol acrylate, propylene glycol dimethacrylate, and diethylene glycol dimethacrylate.

[0231] Other examples include vinylpyrrolidone and / or polythiol compounds having two or more thiol groups in the molecule, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, and pentaerythritol tetrathioglycol.

[0232] In particular, when curing by ultraviolet light, the curable resin liquid Raq can be mixed with a photopolymerization initiator and / or a photosensitizer before use.

[0233] Examples of photopolymerization initiators to be included in the curable resin liquid Raq include acetophenones, benzophenones, Michler-benzoyl benzoate, α-amyloxime esters, tetramethylmeuram monosulfide, and thioxanthones.

[0234] (Filling with curable resin liquid) The curable resin liquid coating device 30 is filled with the curable resin liquid Raq, and the curable resin liquid Raq is filled into the cavity 21 by rotating the concave plate roller 20, which has a mold with a fine uneven structure according to the present invention.

[0235] Examples of photosensitizers to be included in the curable resin liquid Raq include n-butylamine, triethylamine, and tri-n-butylphosphine.

[0236] The viscosity of the curable resin liquid Raq is preferably 5000 cps or less, and more preferably 1000 cps or less, in order to form the fine uneven structure according to the present invention.

[0237] One method for adjusting the viscosity of the curable resin liquid Raq is to indirectly heat the Raq by warming a container filled with the Raq using a fluid such as water, oil, or steam that has been adjusted to an appropriate temperature. Generally, viscosity decreases as the temperature rises, but if the temperature is too high, decomposition and evaporation of the Raq may occur. Therefore, although it varies depending on the type of resin contained in the Raq, the temperature at which the Raq is heated is preferably in the range of approximately 15 to 50°C.

[0238] (Application of curable resin liquid) The curable resin liquid application device 30 is a device for applying the resin liquid Raq to the recessed plate roller 20. The curable resin liquid application device 30 is provided with, for example, a nozzle, which has a T-die shaped rectangular or linear discharge port of a predetermined size, and the longitudinal direction of the discharge port is set in a direction (width direction) perpendicular to the rotation direction of the recessed plate roller 20.

[0239] Furthermore, the curable resin liquid coating apparatus 30 may employ appropriate means such as a roll coating method or a knife coating method to apply the film F.

[0240] A solvent drying device (not shown) may be provided between the curable resin liquid coating device 30 and the pressing roller 40 in the rotational direction of the concave roller 20, and the viscosity of the curable resin liquid Raq may be adjusted by volatilizing the solvent contained in the curable resin liquid Raq using the solvent drying device.

[0241] As a drying method in the solvent drying apparatus described above, for example, a method of applying hot air or a method of heating with an infrared heater can be used. By providing a solvent drying apparatus, solvent-type resins can be incorporated into the curable resin liquid Raq, thus broadening the range of resins that can be used and making it easier to achieve a harmonious coating property.

[0242] (Pressing the film onto the recessed roller) The recessed roller 20 is rotated further, and the surface of the film F opposite to the adhesive layer, which is traveling in sync with the rotation direction of the recessed roller 20, is pressed against the curable resin liquid Raq filled in the recessed roller 20 by the pressing roller 40, thereby bringing the curable resin liquid Raq and the surface of the adhesive layer of the film F into contact.

[0243] The pressure roller 40 is not particularly limited as long as it can press the film F. The pressure roller 40 is usually about 140 mm in diameter. The pressure roller 40 can also be made of materials such as silicone rubber, NBR, or EPT.

[0244] The pressure roller 40 is rotatable in order to feed the film F. The pressure roller 40 may rotate together with the concave plate roller 20, but it can also be driven by a drive device.

[0245] (Curing of the curable resin liquid) The recessed roller 20 is rotated further, and ionizing radiation is irradiated from the curing device 50 to cure the curable resin liquid Raq. At this time, the cured curable resin liquid Raq is in contact with the surface of the film F, so the cured curable resin liquid Raq, that is, the cured product Hraq of the curable resin liquid, is formed on the surface of the film F.

[0246] The curing apparatus 50 is a device that cures the curable resin liquid Raq by irradiating it with ionizing radiation. Here, "ionizing radiation" refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing and crosslinking molecules, and typically ultraviolet rays, electron beams, etc., are used as ionizing radiation. When the ionizing radiation is ultraviolet rays, ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, black light lamps, and metal halide lamps, etc., can be used as ultraviolet light sources.

[0247] Furthermore, various electron beam accelerators such as Cockcroft-Walton type, Van de Graaff type, resonant transformer type, insulated core transformer type, or linear type, Dynamitron type, and high-frequency type can be used as the electron beam light source. The electron irradiation energy is preferably in the range of 100 to 1000 keV, and more preferably in the range of 100 to 300 keV. The irradiation dose is usually preferably in the range of 0.5 to 30 Mrad.

[0248] (Film peeling) The recessed roller 20 is rotated further, and the film F, on which the cured resin liquid Raq has formed, is peeled off from the recessed roller 20 by the recessed roller 60.

[0249] The indented plate roller 60 is rotatable in order to feed the film F. The indented plate roller 60 may rotate together with the indented plate roller 20, but it can also be driven by a drive device.

[0250] Thus, the shape imparted to the hardened layer according to the present invention is achieved.

[0251] 4. Carrier Film The laminated film according to the present invention may have a carrier film. Examples of the configuration of a laminated film having a carrier film include the following (1) and (2): (1) Carrier film / base film / adhesive layer / cured layer (2) Carrier film / second adhesive layer / base film / first adhesive layer / cured layer

[0252] Figure 9 is a schematic diagram of a laminated film having the configuration of a carrier film / base film / adhesive layer / cured layer, and Figure 10 is a schematic diagram of a laminated film having the configuration of a carrier film / second adhesive layer / base film / first adhesive layer / cured layer. The laminated film according to the present invention may also be one in which a cured layer is formed on the adhesive layer of the laminated film in Figure 9, or on the first adhesive layer of the laminated film in Figure 10.

[0253] Figure 9 shows the carrier film CF being peeled off from the base film SF. The carrier film is coated with an adhesive layer LAL, making it easier to peel the carrier film CF off the base film SF in a subsequent process.

[0254] The laminated film shown in Figure 9 is a laminated film comprising a carrier film SF, a base film SF, an adhesive layer AL, and a cured layer L in that order.

[0255] Figure 10 shows a configuration in which the second adhesive layer is positioned between the carrier film and the base film, and illustrates the peeling of the carrier film CF from the second adhesive layer AL2. The carrier film CF is coated with an adhesive layer LAL, making it easier to peel the carrier film CF from the second adhesive layer AL2 in a subsequent process.

[0256] Normally, a laminate film is applied to protect the adhesive layer of a laminated film. However, if the thickness of the laminated film is approximately 100 μm or less, a carrier film may be used instead of a laminate film from the perspective of ease of transport in subsequent processes.

[0257] The laminated film in Figure 10 contains (meth)acrylate in both the first adhesive layer AL1 and the second adhesive layer AL2. Furthermore, the hardness HA of the first adhesive layer AL1 and the hardness HB of the base film, calculated by nanoindentation, satisfy the following formulas (1) and (2). In addition, the surface of the cured layer L opposite to the first adhesive layer AL1 side (the outermost surface) has a fine uneven structure. Formula (1) 0.26 ≤ HA ≤ 0.50 [GPa] Formula (2) 0.20 ≤ HB ≤ 0.36 [GPa]

[0258] (4.1) Resins constituting the carrier film The resin constituting the carrier film is not particularly limited, but examples include cycloolefin resins, polyester resins, polycarbonate resins, polyamide resins, etc. Among these, it is preferable that the resin is a polyester resin from the viewpoint of suppressing curling. Furthermore, it is preferable that the polyester resin is polyethylene terephthalate (PET) from the viewpoint of transparency and water resistance.

[0259] (4.2) Thickness of the carrier film The thickness of the carrier film according to the present invention is preferably in the range of 25 to 100 μm. If the thickness is 25 μm or more, the protective functions such as transportability and scratch prevention of the base film can be fully exhibited. If the thickness is 100 μm or less, the enlargement of the film roll diameter when storing the laminated film of the present invention can be suppressed, and the peeling of the carrier film from the base film during transport of the laminated film can be suppressed. Furthermore, if the thickness is in the range of 30 to 70 μm, it is preferable that the bending of the carrier film and the enlargement of the roll diameter during transport of the laminated film can be suppressed.

[0260] The method for measuring the thickness of a carrier film according to the present invention can be used, for example, by the method described in JIS B 7502 for measuring with a micrometer. Specifically, the thickness of a portion of the carrier film is measured at 10 random locations. Then, the arithmetic mean of the 10 measured values ​​is calculated, and this arithmetic mean is taken as the thickness of the carrier film.

[0261] (4.3) Peel Adhesion to the First Adhesive Layer The peel adhesion of the carrier film according to the present invention to the first adhesive layer is preferably in the range of 0.1 to 5.0 [N / 25 mm] from the viewpoint of suppressing deterioration of clarity and suppressing optical unevenness. If the above adhesion is higher than 0.1 [N / 25 mm], lifting of the carrier film is less likely to occur when the cured layer is formed, thereby enabling the formation of a uniform cured layer and preventing deterioration of clarity. If it is less than 5.0 [N / 25 mm], wrinkles are less likely to occur in the cured layer when the carrier film is removed from the laminated film, and optical unevenness is less likely to occur. More preferably, it is in the range of 0.5 to 4.0 N / 25 mm. In addition, since the adhesive layer may change over time, it is preferable to perform the evaluation under consistent storage and humidity control conditions.

[0262] The peel-off adhesive strength [N / 25mm] of the carrier film to the first adhesive layer according to the present invention can be measured, for example, by the 180-degree peel test method specified in JIS Z 0237:2009 (Test methods for adhesive tapes and adhesive sheets). Any value can be used for the peel speed, but in this case, a value evaluated at a speed of about 2 to 3 m / min is used.

[0263] The peel-off adhesive strength [N / 25mm] of the carrier film to the first adhesive layer can be measured, for example, by cutting the laminated film to a size of 25mm width and 100mm length, leaving it for 2 hours under conditions of 25°C and 50% RH, and then measuring it at a rate of 2.3 m / min.

[0264] (4.4) Other commercially available carrier films according to the present invention include, for example, the surface protection films SAT series (manufactured by Sanei Kaken Co., Ltd.) and PAC series, and the surface protection film (ZACROS) series manufactured by Fujimori Kogyo Co., Ltd., which can be suitably used.

[0265] [II. Display Device] The organic EL or inorganic EL display device of the present invention is a display device comprising an optical film, characterized in that the laminated film of the present invention is provided as the optical film.

[0266] A laminated film obtained by peeling off the carrier film from the laminated film shown in Figures 9 and 10, and forming a hardened layer on one or both sides of the laminated film, can be applied, for example, to a self-emitting light source in the above-mentioned display device.

[0267] Examples of self-emitting light sources include surface-emitting OLEDs or other suitable self-emitting light sources. These self-emitting light sources are manufactured separately from the laminated film, and are used to fabricate display devices such as enhanced light-emitting optical devices.

[0268] To provide enhanced optical performance for OLEDs, the laminated film of the present invention is applied to the light-emitting surface of the OLED.

[0269] Before application, the carrier film is removed from the laminated film to expose the surface. In some cases, the photo-coupled surface of the laminated film of the present invention may be directly positioned relative to the light-emitting surface of the OLED.

[0270] Direct contact between the surface of the portion of the laminated film of the present invention excluding the carrier film (the photo-bonding surface) and the light-emitting surface of the OLED may be sufficient to create a film bond between the two components without having a significant air gap between them.

[0271] Thus, the combination of the laminated film portion of the present invention, excluding the carrier film, and an OLED can be implemented using a wide variety of known OLEDs, including non-pixelated OLEDs that are commonly used in lighting applications. They are particularly practical when used with pixelated OLEDs that are commonly used to generate images in electronic displays.

[0272] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" or "%" are used, and unless otherwise specified, they represent "parts by mass" or "mass%".

[0273] Laminated films [1] to

[72] were prepared as laminated films. First, laminated films [1] to

[70] were prepared, which consisted of a base film, an adhesive layer, and a cured layer in that order. Subsequently, laminated films

[71] and

[72] were prepared, which consisted of a carrier film, a second adhesive layer, a base film, a first adhesive layer, and a cured layer in that order.

[0274] [Preparation of Laminated Films [1] to

[70] ] [1] Preparation of Protective Film and Carrier Film In preparing the laminated film, the protective film and carrier film listed in Table I below were prepared.

[0275]

[0276] [2] Preparation of base films Base films [A-1] to [A-3], [B-1], [C-1] to [C-3], and [D-1] were prepared as base films to be used for each laminated film.

[0277] The manufacturing process for each base film is shown below.

[0278] [2-1] Substrate Film [A-1] (Dope Preparation) 100 parts by mass of purified toluene and 100 parts by mass of norbornene methyl ester were placed in a stirring device. Next, 25 mmol% (relative to monomer mass) of ethylhexanoate-Ni dissolved in toluene, 0.225 mol% (relative to monomer mass) of tri(pentafluorophenyl)boron, and 0.25 mol% (relative to monomer mass) of triethylaluminum dissolved in toluene were placed in a stirring device. The mixture was then reacted at room temperature with stirring for 18 hours. After the reaction was complete, the reaction mixture was added to excess ethanol to produce a polymer precipitate.

[0279] The precipitate was purified, and the resulting cyclic polyolefin polymer (P-1) was dried under vacuum at 65°C for 24 hours.

[0280] Next, the following composition [1] containing the cyclic polyolefin polymer (P-1) prepared by the above method was placed in a mixing tank, stirred to dissolve each component, and then filtered through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm.

[0281] Composition [1] Cyclic polyolefin polymer (P-1) 150 parts by mass Dichloromethane 380 parts by mass Ethanol 70 parts by mass

[0282] This allowed us to prepare dope (D-1).

[0283] Next, the following composition [2], containing the fine particles "Aerosil R812", dichloromethane, ethanol, and the dope (D-1) prepared by the above method, was placed in a disperser in the following quantities to prepare a fine particle dispersion (M-1). The fine particles "Aerosil R812" are manufactured by Nippon Aerosil Co., Ltd., and have a primary mean particle size of 7 nm and an apparent specific gravity of 50 g / L.

[0284] • Composition [2] Fine particles "Aerosil R812" 4 parts by mass Dichloromethane 76 parts by mass Ethanol 10 parts by mass Dope (D-1) 10 parts by mass

[0285] Separately from the 10 parts by mass of the prepared dope (D-1), 100 parts by mass of the dope (D-1) were set aside, and these 100 parts by mass of dope (D-1) were mixed with 0.75 parts by mass of the fine particle dispersion (M-1).

[0286] This resulted in the preparation of a film-forming dope [COP1] containing a cycloolefin resin as the resin composition.

[0287] (Casting of dope and web formation) The dope [COP1] described above was delivered to the casting die through a conduit via a pressurized metering gear pump. The dope [COP1] was then cast from the casting die in a width of 1300 mm to the casting position on a support made of an endlessly rotating stainless steel belt that continuously transports material. At this time, the dope [COP1] was heated on the support until it became self-supporting, and the solvent was evaporated to dry it until it could be peeled off the support by a peeling roller, thereby forming the web [1]. At this time, the transport speed of the dope [COP1] was V １ The speed was 55 m / min.

[0288] (Web peeling) After forming the web [1], the web was peeled off from the support using a peeling roller while maintaining its self-supporting properties.

[0289] (Web stretching) The web [1] was subjected to high-temperature treatment without maintaining its width to increase its density, and then stretched while shrinking in the width direction relative to the width of the web [1] immediately after casting. At this time, the amount of residual solvent immediately before stretching was measured to be 12% by mass. The stretching was carried out at a stretching ratio of 1.50 times.

[0290] (Drying the web) The web [1] was then heated on a support to evaporate the solvent from the web [1].

[0291] (Cutting the web) The web [1], from which the solvent had been evaporated, was cut at both ends in the width direction. The resulting material was designated as the raw film [1].

[0292] (Winding of raw film roll) The above raw film roll [1] is transported at a transport speed V １ (V １The material was transported at 55 m / min and wound onto a core using a winding device. The initial tension was 50 N, the taper was 70%, and the corners were 25%.

[0293] (Unwinding the raw film roll) The wound raw film roll [1] is transported at a transport speed V ２ (V ２ It was released at a rate of 10 m / min.

[0294] (Stretching of the raw film roll) The unwound raw film roll [1] is transported within the stretching device at a speed V ２ (V ２ The material was stretched while being transported at a speed of 10 m / min. The amount of residual solvent immediately before stretching was measured to be 0.30% by mass. The stretching was performed at a ratio of 1.40.

[0295] (Cutting of the raw film) The stretched raw film [1] was cut at both ends in the width direction. The film produced in this way is designated as the base film [A-1].

[0296] <Hardness and Thickness of the Base Film> The base film [A-1] was prepared using the above process. The thickness of the base film [A-1] prepared using the above process was 30 μm, and its hardness was 0.3 GPa.

[0297] The thickness of the base film was measured using the method described above for micrometers in JIS B 7502. Specifically, the thickness of a portion of the base film was measured at 10 random locations, and the arithmetic mean of these 10 measurements was calculated and used as the thickness of the base film. The hardness HB of the base film was calculated using the nanoindentation method.

[0298] <Winding of base film> The base film [A-1] described above was wound up while the protective film [PF1] described above was attached to it. The initial tension was 200N, the taper was 70%, and the corners were 25%.

[0299] [2-2] The thickness and hardness of the base films [A-2], [A-3], [A-4], and [A-5] were changed as shown in Table II by adjusting the amount of dope [COP1] and the resin concentration contained in the dope [COP1]. Otherwise, base films [A-2], [A-3], [A-4], and [A-5] were prepared and wound in the same manner as base film [A-1].

[0300] [2-3] Base film [B-1] (Dope preparation) First, sugar ester [T1] and ester compound [E1] were synthesized as components for preparing the dope by the following method.

[0301] For the sugar ester [T1], sucrose was used as the sugar and synthesized by changing the number of substituents on the acetyl group to eight.

[0302] The following components were placed in the specified quantities in a 2L four-necked flask equipped with a thermometer, stirrer, and slow cooler, and the temperature was gradually raised while stirring under a nitrogen atmosphere until it reached 230°C. Components: 1,2-Propylene glycol 251g, Phthalic anhydride 278g, Adipic acid 91g, Benzoic acid 610g, Tetraisopropyl titanate (esterification catalyst) 0.191g

[0303] Subsequently, a dehydration condensation reaction was carried out for 15 hours, and after the reaction was complete, the unreacted 1,2-propylene glycol was removed by vacuum distillation at 200°C, thereby synthesizing ester compound [E1] with an acid value of 0.10 and a number average molecular weight of 450.

[0304] After synthesizing the sugar ester [T1] and the ester compound [E1], the following components were added in the following amounts to prepare the dope. Specifically, methylene chloride and ethanol were first added to a pressurized dissolution tank. Then, cellulose ester and the like were added to the pressurized dissolution tank containing the solvent while stirring, and this was heated and completely dissolved while stirring. The "cellulose triacetate" described below has an acetyl group substitution degree of 2.80 and a number average molecular weight of 70,000. "R812" is a mat agent (manufactured by Nippon Aerosil Co., Ltd.). Components: Cellulose triacetate (TAC) 100 parts by mass Sugar ester [T1] 12 parts by mass Ester compound [E1] 4 parts by mass 12% ethanol dispersion of "R812" 1.4 parts by mass Methylene chloride 430 parts by mass Ethanol 40 parts by mass

[0305] Furthermore, the above additive components were placed in a sealed container, dissolved while stirring, and filtered using Asaka Filter Paper No. 244 manufactured by Asaka Filter Paper Co., Ltd. to prepare dope [TAC1].

[0306] (Casting of dope and web formation) The prepared dope [TAC1] was uniformly cast onto a stainless steel band support at a temperature of 22°C and a width of 1.8 m using a belt casting apparatus. The solvent was evaporated on the stainless steel band support until the residual solvent amount was 20%, forming a web [2].

[0307] (Web peeling) After forming the web [2], the web [2] was peeled off from the stainless steel band support with a peeling tension of 162 N / m.

[0308] (Drying the web) The web [2] was then heated on a support at 35°C to evaporate the solvent from the web [2].

[0309] (Cutting the web) The web [2], from which the solvent had been evaporated, was cut at both ends in the width direction to create slits 1.6 m wide. The resulting material was used as the raw film [2].

[0310] (Stretching of the raw film) Subsequently, the raw film [2] was stretched to 1.1 times its original width in the width direction (TD direction) at a temperature of 160°C using a tenter stretcher. At this time, the amount of residual solvent when stretching with the tenter was started was 4% by mass.

[0311] (Drying of the raw film) After that, the drying of the raw film was completed by transporting it through drying zones of 120°C and 140°C using numerous rollers.

[0312] (Cutting of the raw film) The film was slit into 1.3 m wide strips, and knurling was applied to both ends of the film, with a width of 10 mm and a height of 2.5 μm. The film produced in this manner was designated as the base film [B-1].

[0313] <Hardness and Thickness of the Base Film> The base film [B-1] was prepared using the above process. The thickness of the base film [B-1] prepared using the above process was 30 μm, and its hardness was 0.25 GPa.

[0314] (Winding of base film) The base film [B-1] described above was wound up while the protective film [PF1] described above was attached to it.

[0315] [2-4] Base film [C-1] (Dope preparation) First, cellulose ester resin [CE1] was synthesized as a component for preparing the dope by the following method.

[0316] A mixture of sulfuric acid (7.8 parts by mass per 100 parts by mass of cellulose) and a carboxylic acid anhydride was used as a catalyst and cooled to -20°C. This mixture was then added to cellulose derived from hardwood pulp, and acylation was carried out at 40°C. During this process, the type and amount of carboxylic acid anhydride were adjusted to control the type and substitution ratio of acyl groups. Furthermore, after acylation, the mixture was aged at 40°C to adjust the total degree of substitution. This resulted in the synthesis of a cellulose ester resin [CE1] with a total degree of substitution of acyl groups of 2.75, a degree of substitution of acetyl groups of 0.19, a degree of substitution of propionyl groups of 2.56, and a weight-average molecular weight of 200,000.

[0317] The following components were thoroughly dissolved while being heated in the following quantities. Note that the "acrylic resin [A1]" below is "Dianal BR85" manufactured by Mitsubishi Chemical Corporation. Components Acrylic resin [A1] 160 parts by mass Cellulose ester resin [CE1] 86 parts by mass Rubber particles (Kaneka M210, manufactured by Kaneka Corporation) 2.5 parts by mass Methylene chloride 550 parts by mass Ethanol 100 parts by mass

[0318] This allowed us to prepare the dope [CAP1].

[0319] (Casting of dope and formation of web) The dope [CAP1] was uniformly cast onto a stainless steel band support at a temperature of 22°C and a width of 2 m using a belt casting apparatus. The solvent was evaporated on the stainless steel band support until the residual solvent amount was 40% by mass, forming a web [3].

[0320] (Web peeling) After forming the web [3], the web [3] was peeled off the stainless steel band support using a peeling roller with a peeling tension of 150 N / m.

[0321] (Drying and cutting of the web) The peeled web [3] was dried at 35°C to evaporate the solvent and then slit into strips 1.6 m wide.

[0322] (Web stretching: First stretch, MD direction) Subsequently, the rotation speed of the stainless steel band support and the speed of the stretching device (tenter) were adjusted, and the web [3] was stretched in the MD direction. The stretching ratio at this time was calculated from the rotation speed of the stainless steel band support and the speed of the stretching device (tenter) to be 1.2 times. The stretching temperature in the first stretch was set to 50°C.

[0323] The stretching ratio in the MD direction is defined as (transport speed of the web after stretching) / (transport speed of the web before stretching).

[0324] (Web stretching: Second stretch, TD direction) Subsequently, the web [3] was stretched to 1.1 times its original width in the TD direction while being heated to 135°C in a stretching device (tenter). At this time, the amount of residual solvent when stretching began in the stretching device (tenter) was 10% by mass.

[0325] The stretching ratio in the TD direction is defined as (width of the web after stretching) / (width of the web before stretching).

[0326] (Drying the web) After stretching the web [3] in the width direction (TD direction) using a stretching device (tenter), drying was completed by transporting it at 110°C through a drying zone equipped with numerous rollers on the stretching device (tenter). The material produced in this way is called film [3].

[0327] (Film stretching: Third stretch, MD direction) The speed of the stretching device (tenter) and the winding speed were adjusted, and the film [3] was stretched in the MD direction at a stretching temperature of 110°C.

[0328] The stretching ratio in the MD direction was calculated to be 1.2 times based on the speed of the stretching device (tenter) and the winding speed.

[0329] The stretching ratio in the MD direction is defined as (conveying speed of the film after stretching) / (conveying speed of the film before stretching).

[0330] (Cutting the film) Next, both ends of the film [3] were cut to a width of 1.5 m.

[0331] (Winding of film) The film prepared in this manner is referred to as the raw film roll [3]. The residual solvent content of the raw film roll [3] was 0.3% by mass.

[0332] (Stretching of the raw film: Fourth stretch, TD direction) The wound raw film [3] was then unwound from its roll and stretched in a stretching device in the width direction (TD direction) to a stretching ratio of 1.35 times while being heated to 140°C.

[0333] (Cutting the raw film roll) Both ends of the stretched raw film roll [3] were cut to a width of 1.5 m. The film produced in this way was designated as the base film [C-1].

[0334] <Hardness and Thickness of the Base Film> The base film [C-1] was prepared using the above process. The thickness of the base film [C-1] prepared using the above process was 30 μm, and its hardness was 0.3 GPa.

[0335] (Winding of base film) The base film [C-1] described above was wound up while the protective film [PF1] described above was attached to it.

[0336] [2-5] The thickness and hardness of the base films [C-2] and [C-3] were changed as shown in Table II by adjusting the amount of dope [CAP1] and the resin concentration contained in the dope [CAP1]. Otherwise, base films [C-2] and [C-3] were prepared and wound in the same manner as base film [C-1].

[0337] [2-6] Substrate Film [D-1] (Preparation of Support) A commercially available polyethylene terephthalate (PET) film was prepared as the support. The film used was "Toyobo Ester Film (Standard Type) E5100 (Single-Sided Corona) 38 μm" manufactured by Toyobo Co., Ltd.

[0338] <<Hardness and Thickness of the Base Film>> The thickness of the base film [D-1] was 38 μm, and its hardness was 0.371. The hardness was measured by nanoindentation with a maximum load of 40 μN and an indentation displacement of 70 nm.

[0339] [2-7] Summary of the prepared base film The resin type, hardness, and thickness of the base film prepared by the above process are summarized in Table II below.

[0340]

[0341] [3] Formation of the adhesive layer [3-1] Preparation of the composition for forming the adhesive layer [3-1-1] Composition for forming the adhesive layer [α] The following resin, crosslinking agent, and solvent were mixed in the following amounts. Note that "Superflex SF-460" in the following components is manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and is an aqueous dispersion of urethane resin. "Carbodilite V-02-L2" is manufactured by Nisshinbo Chemical Co., Ltd. and is an aqueous crosslinking agent in which a hydrophilic segment is imparted to a polycarbodiimide resin.

[0342] • Resin "Superflex SF-460" 130 parts by mass • Crosslinking agent "Carbodilite V-02-L2" 6 parts by mass • Solvent Water 720 parts by mass Isopropyl alcohol 140 parts by mass

[0343] This allowed us to prepare the adhesive layer-forming composition [α].

[0344] [3-1-2] Composition for forming adhesive layer [β] The following resin, crosslinking agent, and solvent were mixed in the following amounts. In the following components, "M-920" is manufactured by Toagosei Co., Ltd. and is an acrylic acid ester (glycerin acrylate) made from plant-derived glycerin. "Omnirad 184" is a photopolymerization initiator manufactured by IGM Resins B.V.

[0345] • Resin "M-920" 50 parts by mass, Hexamethylene diacrylate (HMDA) 50 parts by mass • Crosslinking agent "Omnirad 184" 5 parts by mass • Solvent Propylene glycol monomethyl ether (PGME) 720 parts by mass, Methyl acetate 180 parts by mass

[0346] This allowed us to prepare the adhesive layer-forming composition [β].

[0347] [3-1-3] Composition for forming adhesive layer [γ] The following resin, crosslinking agent, and solvent were mixed in the following amounts.

[0348] • Resin "M-920" 100 parts by mass • Crosslinking agent "Omnirad 184" 5 parts by mass • Solvent Propylene glycol monomethyl ether (PGME) 720 parts by mass Methyl acetate 180 parts by mass

[0349] This allowed us to prepare the adhesive layer-forming composition [γ].

[0350] [3-1-4] Composition for forming an adhesive layer [δ] The following resin, crosslinking agent, and solvent were mixed in the following amounts. Note that "PETA" in the following components is a condensate of pentaerythritol and acrylic acid.

[0351] • Resin: 80 parts by mass of PETA, 20 parts by mass of HMDA (hexamethylene diacrylate) • Crosslinking agent: 5 parts by mass of Omnirad 184 • Solvent: 720 parts by mass of propylene glycol monomethyl ether (PGME), 180 parts by mass of methyl acetate

[0352] This allowed us to prepare the adhesive layer-forming composition [δ].

[0353] [3-1-5] Summary of Adhesive Layer Forming Compositions The adhesive layer forming compositions were prepared as described above. Table III summarizes the formulations of the adhesive layer forming compositions.

[0354]

[0355] [3-2] Each substrate film, coated, dried, and cured with the adhesive layer-forming composition, was fed out at a transport speed of 20 m / min. At this time, each substrate film was coated with the adhesive layer-forming composition using a vacuum extrude die coater. Thereafter, the films were dried and cured in an atmosphere of 120°C, and each adhesive layer was formed by appropriately adjusting the amount of the adhesive layer-forming composition and the drying time so that the adhesive layer had the hardness and thickness shown in Table IV. At this time, the hardness HA [GPa] and thickness [nm] of the adhesive layer were measured. The hardness HA [GPa] of the adhesive layer was measured using the same nanoindentation method as the substrate film, with a maximum load of 40 μN and an indentation displacement of 70 nm.

[0356] The adhesive layers formed on each substrate film were of a total of 12 types: [α-1], [β-1], [β-2], [β-3], [β-4], [β-5], [β-6], [β-7], [γ-1], [γ-2], [γ-3], and [δ-1]. Table IV summarizes the compositional formulations for forming these adhesive layers, the hardness HA [GPa] of the adhesive layer, and the thickness [nm] of the adhesive layer.

[0357]

[0358] The combinations of each base film and each adhesive layer are as shown in Table IV.

[0359] Based on the above, a base film with an adhesive layer was prepared and wound up while being transported at a transport speed of 20 m / min.

[0360] [4] Formation of the hardened layer [4-1] Preparation of the composition for forming the hardened layer The following components were mixed and stirred. In the following components, "KAYARAD PET-30" is pentaerythritol triacrylate manufactured by Nippon Kayaku Co., Ltd. "Irgacure 184" is a polymerization initiator manufactured by BASF Japan, and "Seikabeam 10-28" is a silicone-based leveling agent manufactured by Dainichi Seika Kogyo Co., Ltd., with a solid content of 10%.

[0361] Ingredients: 30 parts by mass of "KAYARAD PET-30" (binder resin), 1.5 parts by mass of "Irgacure 184" (polymerization initiator), 0.05 parts by mass of "Seikabeam 10-28" (silicone-based leveling agent), 70 parts by mass of methyl isobutyl ketone (solvent)

[0362] This allowed us to prepare a hardened layer-forming composition [Haq].

[0363] [4-2] Application, drying, and curing of the hardened layer-forming composition Each substrate film on which the above adhesive layer has been formed was fed out at a transport speed of 20 m / min, and the hardened layer-forming composition [Haq] was applied to the side with the adhesive layer, dried, and UV cured to form the same hardened layer on a total of 64 different substrate films on which adhesive layers had been formed. This hardened layer will be called hardened layer [H1].

[0364] The thickness of each adhesive layer, base film, and cured layer of the laminated film produced by the above process was measured using the method described above for micrometers in JIS B 7502. Specifically, the thickness of a portion of the film or layer was measured at 10 random locations, the arithmetic mean of the 10 measured values ​​was calculated, and this arithmetic mean was taken as the thickness of the film or layer.

[0365] Furthermore, it was confirmed using a Keyence laser microscope, "Laser Microscope VK-X1000," that the shape of the surface on the adhesive side and the opposite side of the cured layer in each laminated film was a sinusoidal structure with an aspect ratio of approximately 1 and a period of 0.5 to 10 μm, as designed.

[0366] As a result, multiple laminated films were produced, each having a base film, an adhesive layer, and a cured layer in that order.

[0367] [Preparation of Laminated Film

[71] ] The protective film [PF1] and carrier film [CF1] described above were prepared. The base film [A-1] described above was peeled off the protective film [PF1] and then fed out at a transport speed of 20 m / min. At this time, the adhesive layer composition [β] was applied to the base film [A-1] using a vacuum extrude die coater, and dried and cured in an atmosphere of 120°C to form the adhesive layer [β-1] described above. The protective film [PF1] was then attached to the adhesive layer [β-1] while being transported at the same transport speed of 20 m / min as above, and then wound up.

[0368] The protective film [PF1] was peeled off the base film [A-1] that had been wound up and attached, and then the film was unwound at a transport speed of 20 m / min.

[0369] At this time, the adhesive layer composition [β] was applied to the other surface of the substrate film [A-1], where the adhesive layer [β-1] had not yet been formed, using a vacuum extrusion die coater, and dried and cured in an atmosphere of 120°C.

[0370] This formed an adhesive layer [β-1] on the other surface of the base film [A-1].

[0371] Furthermore, while conveying at the same conveying speed of 20 m / min as described above, the carrier film [CF1] was attached to the adhesive layer [β1], i.e., the second adhesive layer, formed on the other surface of the base film [A-1], and then wound up.

[0372] The base film [A-1] with the wound carrier film [CF1] attached was unwound at a transport speed of 20 m / min.

[0373] The curing layer composition [Haq] was applied to the adhesive layer [β-1], which is formed on the side opposite to the carrier film [CF1] with the base film [A-1] in between, i.e., the first adhesive layer, and the curing layer [H1] was formed by drying and UV curing.

[0374] As a result, a laminated film

[71] having a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a cured layer in this order was produced.

[0375] The thickness of each adhesive layer, base film, and cured layer of the laminated film

[71] was measured using the same method as for other laminated films.

[0376] [Preparation of Laminated Film

[72] ] The protective film [PF1] and carrier film [CF1] described above were prepared. The base film [A-1] described above was peeled off the protective film [PF1] and then fed out at a transport speed of 20 m / min. At this time, the adhesive layer composition [β] was applied to the base film [A-1] using a vacuum extrude die coater, and dried and cured in an atmosphere of 120°C to form the adhesive layer [β-1] described above. The protective film [PF1] was then attached to the adhesive layer [β-1] while being transported at the same transport speed of 20 m / min as above, and then wound up.

[0377] Furthermore, while transporting at the same transport speed of 20 m / min as described above, the carrier film [CF1] was attached to the surface opposite to the adhesive layer [β1] formed on the surface of the base film [A-1], and then wound up.

[0378] The base film [A-1] with the wound carrier film [CF1] attached was unwound at a transport speed of 20 m / min.

[0379] The curing layer composition [Haq] was applied to the adhesive layer [β-1], which is formed on the opposite side of the carrier film [CF1] with the base film [A-1] in between, and then dried and UV cured to form the cured layer [H1].

[0380] As a result, a laminated film

[72] having a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a cured layer in this order was produced.

[0381] The thickness of each adhesive layer, base film, and cured layer of the laminated film

[72] was measured using the same method as for other laminated films.

[0382] [5] Evaluation Furthermore, the degree of delamination between the substrate and the cured layer was evaluated as peel force for these multiple laminated films using the evaluation method and criteria shown below. In addition, the degree of optical uniformity was evaluated for the above laminated films using the evaluation method and criteria shown below. Tables V to VIII summarize the combinations of substrate films, adhesive layers, and cured layers that were prepared, and describe the evaluation of each.

[0383] [5-1] Peeling force <Evaluation method> The peeling force was measured and evaluated according to the Japanese Industrial Standard JIS K 5600-5-6:1999 General test methods for paints Part 5: Mechanical properties of paint films Section 6: Adhesion (cross-cut method). Figure 11 is a classification table of the test results for peeling evaluation. Figure 11 is a top view from the left side of Figures 9 and 10, and shows the cross-cut surface after the adhesive tape applied after the cross-cut has been peeled off.

[0384] <Evaluation Criteria> In Figure 11, classification 0 was assigned "A", classification 1 was assigned "B", and classification 2 was assigned "C".

[0385] [5-2] Optical Irregularities <Evaluation Method> The laminated film was left standing in a room at a temperature of 25°C and a humidity of 65% for 30 minutes. A fluorescent lamp was projected onto the film surface from 45° above, 1 m away from the surface where the number of continuous optical irregularities in the longitudinal direction was to be counted. The number of optical irregularities was visually counted from 45° below, 0.5 m away from the surface where the optical irregularities were to be counted. One optical irregularity was defined as a convex optical irregularity in the longitudinal direction of the film relative to the surface being observed, and the number of wrinkles in the width direction of the film was counted. The surface on which the number of optical irregularities was measured was the surface from which the hardened layer had been peeled off the substrate.

[0386] <Evaluation Criteria> A: The number of optical irregularities is within the range of 0 to 5 lines / m. B: The number of optical irregularities is within the range of 6 to 10 lines / m. C: The number of optical irregularities is within the range of 11 to 19 lines / m. D: The number of optical irregularities is 20 lines / m or more.

[0387]

[0388]

[0389]

[0390]

[0391] [Fabrication and performance verification of display devices] When the carrier film [CF1] was peeled off the laminated film

[71] and attached to the surface of an existing OLED device, it was confirmed that the brightness of the OLED device with the laminated film

[71] attached was uniformly improved compared to the OLED device without the laminated film.

[0392] Furthermore, when the carrier film [CF1] was peeled off the laminated film

[72] and attached to the surface of an existing OLED device, it was confirmed that the OLED device with the laminated film

[72] attached showed a more uniform improvement in brightness compared to the OLED device without the laminated film.

[0393] From Tables V to VIII, it can be seen that the laminated films of the examples all received an A rating in at least peel strength, whereas the laminated films of the comparative examples, while some received an A rating in optical uniformity, did not receive an A rating in peel strength. Furthermore, it can be seen that the laminated films of the examples are overall superior to the laminated films of the comparative examples in terms of optical uniformity as well.

[0394] From the above, it can be seen that the laminated film of the example, that is, the laminated film of the present invention, is a laminated film that is less prone to delamination from the substrate and can suppress optical unevenness.

[0395] Although embodiments of the present invention have been described and illustrated in detail above, the disclosed embodiments are illustrative and for illustrative purposes only and are not limiting. The scope of the present invention should be interpreted by the terms of the appended claims.

[0396] According to the laminated film of the present invention, delamination from the substrate is less likely to occur, and optical unevenness can be suppressed.

[0397] 1, 1a Agitator (Agitator Tank) 2 Casting Die 3 Support (Endless Belt, Drum) 3a, 3b Rollers 4 Peeling Roller 5 Web (Casting Film) 6 Stretching Equipment (Tenter Stretching Equipment, Oblique Stretching Equipment) 7 Drying Equipment 8 Cutting Section 9 Winding Equipment 10 Stretching Equipment 110 Housing 111 Clip 112 Rail 11 Cutting Section 12 Winding Equipment 20 Concave Roller 21 Cavity 30 Curable Resin Liquid Coating Equipment 40 Press Roller 50 Curing Equipment 60 Peeling Roller F1, F2, F3 Laminated Film F Film a Starting point of film stretching, entrance to stretching zone b Ending point of film stretching, entrance to film width holding zone c Starting point of stress relaxation treatment on film c, entrance to stress relaxation zone d Ending point of stress relaxation treatment, exit to stress relaxation zone Hc Film width at the entrance of the stress relaxation zone Hd Film width at the exit of the stress relaxation zone SF Base film CF Carrier film L Cured layer AL1 First adhesive layer AL2 Second adhesive layer L Cured layer Raq Curable resin liquid Hraq Cured product of curable resin liquid AL Adhesive layer LAL Adhesive layer of carrier film CF

Claims

1. A laminated film comprising a base film, an adhesive layer, and a cured layer in this order, wherein the base film contains at least one of a cycloolefin resin or a cellulose ester resin, the adhesive layer contains (meth)acrylate, the hardness HA of the adhesive layer and the hardness HB of the base film, calculated by nanoindentation, satisfy the following formulas (1) and (2), and the surface of the cured layer opposite to the adhesive layer has a fine uneven structure. Formula (1) 0.26 ≤ HA ≤ 0.50 [GPa] Formula (2) 0.20 ≤ HB ≤ 0.36 [GPa] 2. The laminated film according to claim 1, characterized in that the base film contains a cycloolefin resin.

3. The laminated film according to claim 1, characterized in that the hardness HA of the adhesive layer, calculated by nanoindentation, is in the range of 0.34 to 0.40 GPa.

4. The laminated film according to claim 1, characterized in that the thickness of the base film is in the range of 10 to 45 μm, and the thickness of the adhesive layer is in the range of 400 to 2000 nm.

5. The laminated film according to claim 1, characterized in that the thickness of the base film is in the range of 10 to 45 μm, and the thickness of the adhesive layer is in the range of 600 to 1000 nm.

6. The laminated film according to claim 1, characterized in that, when the adhesive layer is the first adhesive layer, a second adhesive layer is provided on the side opposite to the first adhesive layer, sandwiching the base film.

7. The laminated film according to claim 1, characterized in that it comprises a carrier film, a base film, an adhesive layer, and a cured layer in this order.

8. The laminated film according to claim 7, characterized in that a second adhesive layer is provided between the carrier film and the base film.

9. An organic EL or inorganic EL display device characterized by comprising a laminated film according to any one of claims 1 to 8.

Images