Laminated film, method for producing same, and display device

Abstract

The present invention addresses the problem of providing: a laminated film that is less likely to thermally contract, suppresses optical unevenness, and is capable of suppressing a decrease in clarity; a method for manufacturing the same; and a display device.　This laminated film is characterized by comprising a carrier film, a first adhesive layer, a base material film, a second adhesive layer, and a plurality of cured layers in this order, the first adhesive layer and the second adhesive layer containing at least inorganic particles and a polyolefin resin, a heat shrinkage ratio X in the longitudinal direction and a thermal shrinkage ratio Y in the width direction, in a portion of a laminated body comprising the first adhesive layer, the base material film, and the second adhesive layer, satisfying expression (1) and expression (2) under the condition of 130°C for 90 minutes, and furthermore, the base material film containing a cycloolefin-based resin, beads being contained between the plurality of cured layers, and the plurality of cured layers having the refractive index difference.　Expression (1): Y < X [%]; Expression (2): 0.004 < {(X+Y) / 2} < 0.16 [%]

Description

Laminated film, its manufacturing method and display device

[0001] The present invention relates to a laminated film, a manufacturing method thereof, and a display device. More specifically, the present invention relates to a laminated film that is resistant to thermal shrinkage, suppresses optical unevenness, and suppresses deterioration of clarity.

[0002] Recently, organic light-emitting diodes (OLEDs) using organic electroluminescence (EL) are used in various fields. These organic light-emitting diodes are used, for example, in display devices. Patent Literature 1, for example, discloses a light extraction film as a new component aimed at further improving the functionality of these organic light-emitting diodes, such as improving image quality and reducing power consumption. Thus, techniques for improving light extraction technology have been attempted.

[0003] Furthermore, in the components for organic EL devices as described above, thinning is required from the viewpoint of functionality and reducing environmental impact. However, this makes the components more susceptible to thermal shrinkage, which leads to optical unevenness, reduced clarity, and poor appearance.

[0004] Here, "clarity" is a parameter related to the occurrence of focus blur when a displayed pattern or the like is viewed. For example, when a pattern is viewed through a laminate, if the pattern is visible, it means that there is no focus blur, i.e., the clarity is high. If the pattern appears blurred, it means that there is focus blur, i.e., the clarity is low. Such a decrease in clarity is a performance that occurs when light passing through the laminate is scattered within a narrow angle range, and this uniformity is an important indicator that directly affects the image quality of the display.

[0005] JP 2017-84821 A

[0006] The present invention has been made in consideration of the above problems and circumstances, and its problem to be solved is to provide a laminated film that is less likely to undergo thermal shrinkage, suppresses optical unevenness, and suppresses deterioration of clarity, as well as a method for manufacturing the same and a display device.

[0007] In order to solve the above-mentioned problems, the present inventors have investigated the causes of the above-mentioned problems and have found that the above-mentioned problems can be solved by controlling the thermal shrinkage rates in the longitudinal and lateral directions of a specific laminate portion of a laminate film within a certain range, thereby arriving at the present invention. That is, the above-mentioned problems according to the present invention are solved by the following means.

[0008] 1. A laminate film comprising, in this order, a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a plurality of cured layers, wherein the first adhesive layer and the second adhesive layer contain at least inorganic particles and a polyolefin resin, and wherein a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer is subjected to measurement of heat shrinkage at 130°C for 90 minutes, and where X and Y are the heat shrinkage in the longitudinal direction and the width direction, respectively, X and Y satisfy the following formulas (1) and (2): Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%], further wherein the base film contains a cycloolefin resin, and beads are contained between the plurality of cured layers, and the plurality of cured layers have a refractive index difference.

[0009] 2. The laminate film according to item 1, wherein the carrier film contains at least polyethylene terephthalate, and the peel adhesive strength of the carrier film to the first adhesive layer is within the range of 0.1 to 0.4 [N / 25 mm].

[0010] 3. The laminated film according to item 1, wherein the first adhesive layer and the second adhesive layer contain the same compound and have the same thickness.

[0011] 4. The laminated film according to item 1, wherein the refractive indexes of the plurality of cured layers gradually increase from the substrate side toward the outermost layer side.

[0012] 5. A method for producing the laminated film according to any one of items 1 to 4, comprising the step of measuring the thermal shrinkage of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer under conditions of 130°C for 90 minutes, and adjusting X and Y so that X and Y satisfy the following formulas (1) and (2), where X and Y are the thermal shrinkage in the longitudinal direction and the width direction, respectively: Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%]

[0013] 6. A display device including an optical film, characterized in that the display device includes a portion of the laminate film according to any one of items 1 to 4 excluding the carrier film as the optical film.

[0014] The present invention provides a laminated film that is less susceptible to thermal shrinkage, suppresses optical unevenness, and suppresses deterioration of clarity, as well as a method for producing the same and a display device. The mechanism by which the effects of the present invention are exerted or acted upon is not clear, but is speculated as follows.

[0015] The laminate film of the present invention is a laminate film comprising, in this order, a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a plurality of cured layers, wherein the first adhesive layer and the second adhesive layer contain at least inorganic particles and a polyolefin resin, and the thermal shrinkage of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer is measured under conditions of 130°C for 90 minutes, and when the thermal shrinkage in the longitudinal direction and the width direction is X and Y, respectively, X and Y satisfy the following formulas (1) and (2): Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%] Furthermore, the base film is characterized in that it contains a cycloolefin resin, beads are contained between the plurality of cured layers, and the plurality of cured layers have a refractive index difference.

[0016] As described above, in the prior art, when a thin laminate is used, thermal shrinkage is likely to occur, and there are problems such as optical unevenness, loss of clarity, and poor appearance due to the thermal shrinkage.

[0017] In particular, when the film is processed in a roll-to-roll manner, the above-mentioned problems are more pronounced for the following reasons.

[0018] When film processing is performed in a roll-to-roll manner, it is relatively easy to control the tension in the longitudinal direction, but it is difficult to control the tension in the width direction. When heat is applied to the film, the dimensions of the film change, especially from the outside in the width direction, causing processing irregularities.

[0019] In the present invention, the thermal shrinkage of the laminate portion of the laminate film, which is composed of the first adhesive layer, the base film, and the second adhesive layer, is controlled to satisfy the relationship of the following formula (2). In addition, in consideration of the balance between the thermal shrinkage in the longitudinal direction and the width direction, the thermal shrinkage in the longitudinal direction is intentionally set to satisfy formula (1), i.e., the thermal shrinkage in the longitudinal direction is set to be greater than the thermal shrinkage in the width direction. This is presumably what makes it possible to suppress optical unevenness, loss of clarity, and poor appearance caused by the thermal shrinkage.

[0020] Furthermore, since there is the first adhesive layer and the second adhesive layer, and both adhesive layers contain at least inorganic particles and a polyolefin resin with excellent flexibility, transparency can be ensured, and appropriate adhesion can be maintained while appropriately maintaining anti-blocking properties (resistance that prevents films from adhering to each other) between the base film and the carrier film, or between the base film and the cured layer (functional layer).

[0021] Furthermore, since the base film contains a cycloolefin resin, moisture permeability is reduced. Furthermore, the refractive index is varied by the beads contained between the multiple cured layers, which is presumably why light extraction performance is improved.

[0022] An example of a schematic configuration diagram of a laminate film when the cured layer has a two-layer structure.An example of a schematic configuration diagram of a laminate film when the cured layer has a two-layer structure.An example of a schematic configuration diagram of a laminate film when the cured layer has a two-layer structure.An example of a schematic configuration diagram of a laminate film when the cured layer has a three-layer structure.An example of a schematic configuration diagram of a laminate film when the cured layer has a three-layer structure.An example of a schematic configuration diagram of a laminate film when the cured layer has a three-layer structure.A flow chart showing the flow of the production process of the laminate film of the present invention.A flow chart showing the flow of the production process of a base film by solution casting method.By solution casting method A schematic diagram of an apparatus for producing a base film. A plan view schematically showing the internal configuration of a tenter stretching apparatus. A side view of the three zones in the tenter stretching apparatus. A plan view of the three zones in the tenter stretching apparatus. A schematic diagram of the nozzle and heater installation parts when the three zones in the tenter stretching apparatus are viewed from the front. A flowchart showing the flow of the process for producing a base film by melt casting. A schematic diagram of an apparatus for producing a base film by melt casting. An example of a specific example in which the part excluding the carrier film from the laminate film of the present invention can be used as a self-emitting light source. An example of a specific example in which the part excluding the carrier film from the laminate film of the present invention can be used as a self-emitting light source.

[0023] The laminate film of the present invention is a laminate film comprising, in this order, a carrier film, a first adhesive layer, a base film, a second adhesive layer, and multiple cured layers, wherein the first adhesive layer and the second adhesive layer contain at least inorganic particles and a polyolefin resin, and the thermal shrinkage of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer is measured under conditions of 130°C for 90 minutes, and when the thermal shrinkage in the longitudinal direction and the width direction is X and Y, respectively, X and Y satisfy the following formulas (1) and (2): Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%] Furthermore, the base film contains a cycloolefin resin, beads are contained between the multiple cured layers, and the multiple cured layers have a refractive index difference. This feature is a technical feature common to or corresponding to each of the following embodiments (aspects).

[0024] In one embodiment of the present invention, the carrier film contains at least polyethylene terephthalate, and the peel adhesive strength of the carrier film to the first adhesive layer is preferably within a range of 0.1 to 0.4 [N / 25 mm] from the viewpoint of suppressing deterioration of clarity and suppressing optical unevenness, and more preferably within a range of 0.2 to 0.3 [N / 25 mm].

[0025] From the viewpoint of preventing deterioration of clarity, it is preferable that the first adhesive layer and the second adhesive layer contain the same compound and have the same thickness. In the present invention, "having the same thickness" may be practically considered to be the same thickness if the difference is within a range of about ±2%.

[0026] From the viewpoint of improving light extraction performance, it is preferable that the refractive indexes of the plurality of cured layers gradually increase from the substrate side toward the outermost layer side.

[0027] The method for producing a laminated film of the present invention can be suitably used for producing the laminated film of the present invention.

[0028] The display device of the present invention can be suitably used by providing the portion of the laminate film of the present invention excluding the carrier film as an optical film.

[0029] The present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0030] [I. Laminated Film] The laminated film of the present invention is a laminated film comprising a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a plurality of cured layers in this order, wherein the first adhesive layer and the second adhesive layer contain at least inorganic particles and a polyolefin resin, and wherein a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer is measured for heat shrinkage at 130°C for 90 minutes, and when the heat shrinkage in the longitudinal direction and the width direction is X and Y, respectively, X and Y satisfy the following formulas (1) and (2): Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%] Furthermore, the base film is characterized in that it contains a cycloolefin resin, beads are contained between the plurality of cured layers, and the plurality of cured layers have a refractive index difference.

[0031] FIG. 1 is a schematic structural diagram of a laminated film of the present invention in which the cured layer has a two-layer structure, and examples thereof include structures such as those shown in FIGS. 1A, 1B, and 1C.

[0032] When the curable layer according to the present invention has a two-layer structure, the laminate film F1 includes a carrier film CF, a first adhesive layer AL1, a base film SF, a second adhesive layer AL2, a curable layer L1, and a curable layer L2, in this order. The first adhesive layer AL1 and the second adhesive layer AL2 contain inorganic particles Ip, and beads Op are contained between the curable layer L1 and the curable layer L2.

[0033] In this case, the cured layer L1 and the cured layer L2 have a refractive index difference, and it is preferable that the cured layer L1 is a low refractive index layer LL and the cured layer L2 is a high refractive index layer LH from the viewpoint of improving light extraction performance.

[0034] In addition, it is preferable that the beads Op are uniformly dispersed at a high density between the hardened layer L1 and the hardened layer L2 as shown in Fig. 1C. The density and uniformity of the beads Op can be evaluated by measuring the clarity of the laminate.

[0035] Although the terms "low refractive index layer" and "high refractive index layer" are used above, the terms "low refractive index" and "high refractive index" are concepts distinguished by their relative relationship, and are not distinguished by a specific numerical value. However, for convenience, in this specification, "low refractive index" refers to a refractive index of 1.49 or less, and "low refractive index layer" refers to a hardened layer having a refractive index of 1.49 or less. Furthermore, "high refractive index" refers to a refractive index greater than 1.49, and "high refractive index layer" refers to a hardened layer having a refractive index greater than 1.49.

[0036] The configuration of the laminated film of the present invention is not limited to the configurations shown in FIGS. 1A, 1B, and 1C, and may have a configuration having a plurality of curable layers.

[0037] FIG. 2 is an example of a schematic structural diagram of a laminated film according to the present invention in which the plurality of curable layers have a three-layer structure, and examples thereof include structures such as those shown in FIGS. 2A, 2B, 2C, and 2D.

[0038] When the curable layer according to the present invention has a three-layer structure, the laminate film F2 includes, in this order, a carrier film CF, a first adhesive layer AL1, a base film SF, a second adhesive layer AL2, a curable layer L1, a curable layer L2, and a curable layer L3. The first adhesive layer AL1 and the second adhesive layer AL2 contain inorganic particles Ip, and beads Op are contained between the curable layer L1 and the curable layer L2.

[0039] In this configuration, it is preferable that the cured layer L1 has a low refractive index and the cured layer L3 has a high refractive index from the viewpoint of improving light extraction performance. Note that the cured layer L2 may have a low refractive index or a high refractive index, but it is preferable that the refractive indexes of the cured layers increase gradually in the order of the cured layer L1, the cured layer L2, and the cured layer L3 from the viewpoint of improving light extraction performance.

[0040] The beads Op may be uniformly dispersed between the hardened layers L1 and L3 as shown in Fig. 2B. Alternatively, the beads Op may be uniformly dispersed only between the hardened layers L1 and L2 as shown in Fig. 2A, or may be contained between the hardened layers across the hardened layer L2 as shown in Fig. 2C. Preferably, the beads Op are uniformly dispersed at a high density between the hardened layers L1 and L2 as shown in Fig. 2D.

[0041] 1. Carrier Film The carrier film provided in the laminate film of the present invention is attached to the substrate film via a first adhesive layer. The carrier film is releasably attached to the surface of the first adhesive layer. The first adhesive layer contains inorganic particles, which ensures transparency and improves anti-blocking properties (resistance to prevent films from adhering to each other). Furthermore, the inclusion of a polyolefin resin improves flexibility, allowing the film to maintain adequate adhesion while suppressing adhesion to the substrate film.

[0042] When the laminated film of the present invention is stored in the form of a film roll, the carrier film plays a role in suppressing adhesion of the base film to other members and preventing damage to the base film.

[0043] The carrier film according to the present invention can be composed of a resin substrate and an adhesive layer provided on one side of the resin substrate. Note that the carrier film may not be provided with the adhesive layer, and a self-adhesive resin film may be used as the carrier film.

[0044] (1.1) Resin Constituting Carrier Film The resin constituting the carrier film is not particularly limited, but examples thereof include cycloolefin-based resins, polyester-based resins, polycarbonate-based resins, polyamide-based resins, etc. Among these, it is preferable that the resin is a polyester-based resin from the viewpoint of suppressing curling. Furthermore, it is preferable that the polyester-based resin is polyethylene terephthalate (PET) from the viewpoint of transparency and water resistance.

[0045] (1.2) Carrier Film Thickness The thickness of the carrier film according to the present invention is preferably within the range of 25 to 100 μm. A thickness of 25 μm or more can adequately exhibit protective functions such as preventing scratches on the base film. Furthermore, a thickness of 100 μm or less can suppress an increase in the film roll diameter during storage of the laminate film of the present invention, and can suppress peeling of the carrier film from the base film during transport of the laminate film. Furthermore, a thickness within the range of 30 to 70 μm is preferable because it can suppress folding of the carrier film and an increase in the roll diameter during transport of the laminate film.

[0046] (Measurement Method) The thickness of the carrier film according to the present invention can be measured, for example, by the method described in the micrometer of JIS B 7502. Specifically, the thickness of a portion of the film or layer is measured at 10 random locations. The arithmetic mean value of the measured values ​​at the 10 locations is then calculated, and this arithmetic mean value is taken as the thickness of the film or layer.

[0047] (1.3) Peel Adhesion Strength from First Adhesive Layer The peel adhesion strength from the carrier film of the present invention to the first adhesive layer is preferably within the range of 0.1 to 0.4 [N / 25 mm] from the viewpoint of suppressing deterioration of clarity and suppressing optical unevenness. If the above adhesive strength is higher than 0.1 [N / 25 mm], the carrier film is less likely to lift during the formation of the cured layer, thereby allowing the cured layer to be formed uniformly and preventing deterioration of clarity. Furthermore, if the adhesive strength is less than 0.4 [N / 25 mm], the cured layer is less likely to wrinkle when the carrier film is removed from the laminated film, making optical unevenness less likely to occur. A more preferred range is 0.2 to 0.3 [N / 25 mm]. Furthermore, because adhesive layers generally change over time, it is preferable to evaluate them under consistent storage and humidity conditions.

[0048] (Measurement Method) The peel adhesive strength [N / 25 mm] of the carrier film according to the present invention to the first adhesive layer 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).

[0049] In this example and the comparative example, the laminated film was cut to a size of 25 mm wide and 100 mm long, and after leaving it under conditions of 25°C and 50% RH for 2 hours, the peel adhesion strength [N / 25 mm] of the carrier film to the first adhesive layer was measured at a speed of 2.3 m / min.

[0050] (1.4) Others Suitable commercially available carrier films for the present invention include, for example, the SAT series and PAC series surface protection films manufactured by Sanei Kaken Co., Ltd. In addition, the ZACROS series surface protection films manufactured by Fujimori Kogyo Co., Ltd. can also be used.

[0051] 2. Laminate portion The laminate portion according to the present invention comprises a first adhesive layer, a base film, and a second adhesive layer. The laminate portion is, for example, the portion of the laminate film F1 in FIG. 1A that comprises the first adhesive layer AL1, the base film SF, and the second adhesive layer AL2.

[0052] (2.1) Heat Shrinkage Rate The heat shrinkage rate of the laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer according to the present invention is calculated under conditions of 130°C for 90 minutes. The heat shrinkage rate of the laminate portion in the longitudinal direction is taken as X, and the heat shrinkage rate in the width direction is taken as Y. In this case, optical unevenness can be suppressed and clarity can be ensured by X and Y satisfying the following formulas (1) and (2).

[0053] Formula (1) Y<X [%] Formula (2) 0.004<{(X+Y) / 2}<0.16 [%]

[0054] The laminated portion according to the present invention is designed to be thin, and is therefore susceptible to thermal shrinkage. In particular, when processing a film using a roll-to-roll method, it is relatively easy to control the tension in the longitudinal direction, but it is difficult to control the tension in the transverse direction. Therefore, when heat is applied to the film, the dimensions of the film change, especially from the outer side in the transverse direction, and processing irregularities occur.

[0055] The main means for controlling the heat shrinkage rate in the present invention is the stretching method in the second-stage stretching step (S9) described below.

[0056] One of the features of the present invention is to control the heat shrinkage rate of the laminate portion, and the effects of the present invention are realized mainly by controlling the heat shrinkage rate of the base film in the laminate portion.

[0057] The primary means for controlling the heat shrinkage rate is to control the residual stress of the polymer constituting the film, which can be achieved by appropriately adjusting the stretching temperature, stretching speed, stretching ratio, heating and holding time, cooling speed, amount of residual solvent, relaxation speed after stretching, etc.

[0058] The heat shrinkage rate can be reduced by, for example, decreasing the stretching speed, increasing the stretching temperature, increasing the heating holding time, or decreasing the cooling rate. Other examples include a step of reducing the stretch ratio by several percent after stretching, or increasing the temperature holding time after stretching at a temperature equal to or higher than the glass transition temperature (Tg) of the polymer.

[0059] Regarding the heating temperature, it is important to set the stretching temperature at a temperature equal to or higher than the glass transition temperature (Tg) of the polymer constituting the film. Regarding the amount of residual solvent, the smaller the amount of residual solvent, the more the above-mentioned effects can be enhanced.

[0060] As a means for reducing the thermal shrinkage rate in the transverse direction (TD), it is effective to subject the film to a film shrinkage process of about several percent in an environment at a temperature equal to or higher than the glass transition temperature (Tg) while holding the edges after stretching.

[0061] In the present invention, the thermal shrinkage of the laminate portion of the laminate film, consisting of the first adhesive layer, the base film, and the second adhesive layer, is controlled to satisfy the relationship of formula (2) above. In addition, the thermal shrinkage is deliberately set to satisfy formula (1) in consideration of the balance between the longitudinal and transverse thermal shrinkages. That is, the longitudinal thermal shrinkage is set to be greater than the transverse thermal shrinkage. This can suppress optical unevenness, loss of clarity, and poor appearance due to thermal shrinkage. In the present invention, the thermal shrinkages X and Y are each arbitrary as long as they satisfy formulas (1) and (2). However, the absolute value of the thermal shrinkage is preferably in the range of 0.0 to 1.0%, taking into account the effective shrinkage of the cured layer after application. It is more preferably in the range of 0.002 to 0.2%, and even more preferably in the range of 0.004 to 0.1%.

[0062] (Methods of Measurement and Calculation) The heat shrinkage rates in the longitudinal direction (MD direction) and width direction (TD direction) of the laminate portion according to the present invention can be calculated, for example, as follows.

[0063] First, a test piece was prepared by cutting a piece of the laminate into a width of 100 mm and a length of 100 mm. Cross scratches were made at the four corners of the test piece (hereinafter, scratches made in this manner will also be referred to as "cross scratches"). The lengths [mm] of the four central points of the cross scratches in the longitudinal direction (MD) and transverse direction (TD) before heating were measured using a CNC three-dimensional measuring machine (product name "LEGEX774") manufactured by Mitutoyo Corporation.

[0064] The laminate is then placed in an oven and heated at 130°C for 90 minutes, then allowed to cool at room temperature for 1 hour, and the lengths (mm) of the four points in the machine direction (MD) and transverse direction (TD) after heating are measured again using the CNC coordinate measuring machine.

[0065] The lengths [mm] before heating and the lengths [mm] after heating in the longitudinal direction (MD direction) and width direction (TD direction) measured at the four points are substituted into the following formula to calculate the heat shrinkage rates in each of the longitudinal direction (MD direction) and width direction (TD direction).

[0066] Heat shrinkage rate [%] = {(length before heating [mm] - length after heating [mm]) / length before heating [mm]} × 100

[0067] (2.2) First Adhesive Layer and Second Adhesive Layer The first adhesive layer and second adhesive layer according to the present invention contain at least inorganic particles and a polyolefin resin. They may also contain other resins. These resins are preferably crosslinked with a crosslinking agent, and may contain other components as needed. That is, the first adhesive layer and second adhesive layer contain a composition containing inorganic particles and a resin (a composition for the first adhesive layer or a composition for the second adhesive layer) or a crosslinked product thereof, and may further contain other components as needed.

[0068] The first adhesive layer and the second adhesive layer contain inorganic particles to provide anti-blocking properties, and the polyolefin resin provides excellent flexibility, allowing the first adhesive layer and the second adhesive layer to maintain appropriate adhesion while adequately maintaining anti-blocking properties between the substrate film and the carrier film, or between the substrate film and the cured layer (functional layer).

[0069] The first adhesive layer and the second adhesive layer contain the same compound and have the same thickness, so that the balance of thermal shrinkage in the thickness direction of the film can be maintained, and the formation of a uniform cured layer can be easily performed. Therefore, from the viewpoint of suppressing deterioration of clarity, it is preferable that the first adhesive layer and the second adhesive layer contain the same compound and have the same thickness.

[0070] (2.2.1) Particles contained in the adhesive layer (inorganic particles) The first adhesive layer and the second adhesive layer according to the present invention contain at least inorganic particles. If necessary, they may also contain other organic particles. By containing inorganic particles, anti-blocking properties can be imparted.

[0071] By containing the above-mentioned inorganic particles or organic particles, the first adhesive layer and the second adhesive layer according to the present invention can form irregularities on the surface of the film, imparting slipperiness and anti-blocking properties.

[0072] Examples of inorganic particles include fine particles of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, etc. Specifically, silicon dioxide particles (for example, "Seahoster Series" KE-P20, KE-P30, etc., manufactured by Nippon Shokubai Co., Ltd.) are preferred.

[0073] The inorganic particles may have an average particle size of, for example, 20 to 500 nm, preferably 50 to 400 nm, which allows for both transparency and anti-blocking properties.

[0074] (Organic Particles) 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, fluorine resin particles, etc. Also included are copolymer resin particles of two or more monomers used in the synthesis of these resins.

[0075] The average particle size of the organic particles may 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 anti-blocking properties can be achieved.

[0076] (2.2.2) Resin Contained in the Adhesive Layer (Polyolefin Resin) The olefin may be an alkene having 2 to 6 carbon atoms, such as ethylene or propylene. The polyolefin according to the present invention is preferably an acid-modified polyolefin. The acid-modified polyolefin is an olefin-based polymer containing structural units derived from an unsaturated carboxylic acid. The olefin-based polymer may be a random copolymer or a graft copolymer. The olefin-based polymer may further contain structural units derived from other copolymerization components, such as a (meth)acrylic acid ester.

[0077] Examples of acid-modified polyolefins include ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid-maleic anhydride copolymers, acid-modified polyethylene, acid-modified polypropylene, acid-modified ethylene-propylene resins, acid-modified ethylene-butene resins, acid-modified propylene-butene resins, and acid-modified ethylene-propylene-butene resins.

[0078] Examples of unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, etc. The content of structural units derived from unsaturated carboxylic acids may be in the range of 0.1 to 25% by mass, preferably 0.5 to 15% by mass, based on the total structural units.

[0079] Commercially available polyolefins include, for example, "Acrydic 52-666" manufactured by DIC Corporation, "Arrowbase Series" trade names SB-1200, SE-1010, SE-1013N, SE-1030N, SD-1010, TC-4010, and TD-4010 manufactured by Unitika Ltd., "High Tech Series" S3148, S3121, S8512, P-5060N, and P-9018 manufactured by Toho Chemical Industry Co., Ltd. Examples of such polyurethanes include Ito Chemicals, Inc.'s trade name "UNISTOR Series" S-120, S-75N, V100, H-200, H-300, and EV210H; Mitsui Chemicals, Inc.'s trade name "CHEMIPEARL Series" XHP-400; Sumitomo Seika Chemicals Co., Ltd.'s trade name "Zaixen Series" Zaixen A and Zaixen L; and Toyobo Co., Ltd.'s trade name "Hardlen Series" NZ-1004, NZ-1005, and NZ-1022.

[0080] [Content] The polyolefin content is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the resin contained in the resin-containing composition (first adhesive layer composition).

[0081] When the resin contained in the resin-containing composition (first adhesive layer composition) includes a polyolefin and a urethane-based resin, the mass ratio thereof may be, for example, polyolefin / urethane-based resin=90 / 10 to 40 / 60 mass ratio, and preferably 90 / 10 to 50 / 50 mass ratio.

[0082] (Other Resins) Examples of resins other than polyolefins contained in the first adhesive layer and the second adhesive layer according to the present invention include polyurethane, polyester, polyvinylidene chloride, acrylic polymers, modified silicone polymers, styrene-butadiene rubber, etc. These resins may be used alone or in combination of two or more. Examples of combinations of two or more resins include a combination of polyolefin and polyurethane.

[0083] [Polyurethane] Polyurethane is a polymer obtained by, for example, reacting a polyol compound with a polyisocyanate compound. Polyurethane contains a polyether polyol as a polyol component. Polytetramethylene glycol is more preferred as the polyether polyol.

[0084] Commercially available polyurethane products include, for example, the Hydran Series manufactured by DIC Corporation, trade names AP-201, AP-40F, HW-140SF, and WLS-202; the Superflex Series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade names SF-210, SF460, SF870, SF420, and SF-420NS; and the Takelac Series manufactured by Mitsui Chemicals, Inc. Examples of such products include the "W-615, W6010, W-6020, W-6061, W-405, W-5030, W-5661, W-512A-6, W-635, WPB-6601, WS-6021, WS-5000, WS-5100, WS-4000, WSA-5920, and WF-764 series manufactured by Adeka Corporation, and the developed product "SPX-0882."

[0085] [Polyester] Examples of commercially available polyester products include "Vylonal Series" MD1400, MD1480, MD1245, and MD1500 manufactured by Toyobo Co., Ltd., and "Pluscoat Series" Z-221, Z-561, Z-730, RZ-142, and Z-687 manufactured by Goo Chemical Industry Co., Ltd.

[0086] [Polyvinylidene Chloride] Commercially available polyvinylidene chloride products include, for example, Saran Latex Series L509, manufactured by Asahi Kasei Corporation.

[0087] [Acrylic Polymer] Commercially available acrylic polymers include, for example, Nippon Shokubai Co., Ltd.'s "Epocross WS Series" WS-700, and Shin-Nakamura Chemical Co., Ltd.'s "New Coat Series."

[0088] [Modified Silicone Polymer] Commercially available modified silicone polymers include, for example, "Ceranate Series" WSA1060 and WSA1070 manufactured by DIC Corporation, and H7620, H7630, and H7650 manufactured by Asahi Kasei Chemicals Corporation.

[0089] [Styrene-Butadiene Rubber] Commercially available styrene-butadiene rubbers include, for example, NIPOL LX415, NIPOL LX407, NIPOL V1004, NIPOL MH8101, and SX1105 manufactured by Nippon Zeon Co., Ltd.

[0090] (2.2.3) Crosslinking Agent The resin is preferably crosslinked with a crosslinking agent. Examples of crosslinking agents include oxazoline compounds, carbodiimide compounds, isocyanate compounds, and epoxy compounds. When the resin is a polyolefin, the crosslinked product of the polyolefin is more preferably a crosslinked product of an acid-modified polyolefin. The "crosslinked product of an acid-modified polyolefin" refers to a crosslinked product of a composition containing an acid-modified polyolefin and a crosslinking agent.

[0091] (Oxazoline Compound) The oxazoline compound may be a compound having two or more oxazoline groups in the molecule. Commercially available oxazoline compounds include, for example, the EPOCROS (registered trademark) series (manufactured by Nippon Shokubai Co., Ltd.), such as WS-700 manufactured by Nippon Shokubai Co., Ltd.

[0092] (Carbodiimide Compound) The carbodiimide compound may be a compound having two or more carbodiimide groups in the molecule. Examples of the carbodiimide compound include those manufactured by Nisshinbo Chemical Inc. under the trade name "Carbodilite Series" V-02, V-02-L2, SV-02, V-04, and E-02.

[0093] (Isocyanate Compound) The isocyanate compound is a compound containing two or more isocyanate groups in one molecule, and may be any of aliphatic isocyanate, aromatic isocyanate, and alicyclic isocyanate. Examples of the isocyanate compound include hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate. The isocyanate compound may also be masked with a blocking agent.

[0094] (Epoxy Compound) As the epoxy compound, a compound having one or more epoxy groups in the molecule is used. Alternatively, when a polymer (epoxy resin) having two or more epoxy groups in the molecule is used, a compound having two or more functional groups reactive with epoxy groups in the molecule may be used in combination.

[0095] Here, examples of the "functional group reactive with an epoxy group" include a carboxy group, a phenolic hydroxy group, a mercapto group, and a primary or secondary aromatic amino group. In consideration of three-dimensional curing properties, it is particularly preferable to have two or more of these functional groups in one molecule. Examples of polymers having one or more epoxy groups in the molecule include epoxy resins.

[0096] [Epoxy Resins] Examples of epoxy resins include bisphenol A epoxy resins derived from bisphenol A and epichlorohydrin, bisphenol F epoxy resins derived from bisphenol F and epichlorohydrin, bisphenol S epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, bisphenol F novolac epoxy resins, alicyclic epoxy resins, diphenyl ether epoxy resins, hydroquinone epoxy resins, naphthalene epoxy resins, biphenyl epoxy resins, fluorene epoxy resins, multifunctional epoxy resins such as trifunctional epoxy resins and tetrafunctional epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, hydantoin epoxy resins, isocyanurate epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated.

[0097] Examples of commercially available epoxy resins include, but are not limited to, the following: Two or more of these epoxy resins may be used in combination.

[0098] Commercially available products manufactured by Japan Epoxy Resins Co., Ltd. include JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, and YX4000.

[0099] Commercially available products manufactured by DIC Corporation include Epicron 830, EXA835LV, HP4032D, and HP820.

[0100] Commercially available products manufactured by ADEKA Corporation include the EP4100 series, EP4000 series, and EPU series.

[0101] Commercially available products manufactured by Daicel Chemical Industries, Ltd. include the Celloxide series (2021, 2021P, 2083, 2085, 3000, etc.), the Epolead series, and the EHPE series.

[0102] Commercially available products manufactured by 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 and having epoxy groups at both ends (YP series).

[0103] Examples of commercially available products manufactured by Nagase ChemteX Corporation include the Denacol series.

[0104] Examples of commercially available products manufactured by Kyoeisha Chemical Co., Ltd. include the Epolite series.

[0105] (2.2.4) Other Components The first adhesive layer and the second adhesive layer according to the present invention may further contain other components in addition to those described above, as necessary. 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, and compatibilizers.

[0106] (2.2.5) Thickness of Adhesive Layer The thickness of the first adhesive layer and the second adhesive layer according to the present invention is not particularly limited. It is preferably in the range of 10 to 1000 nm, more preferably in the range of 20 to 500 nm, and even more preferably in the range of 50 to 400 nm. The thickness of the adhesive layer according to the present invention can be measured by the same method as that for the carrier film described above.

[0107] (2.2.6) Method for forming adhesive layer The first adhesive layer according to the present invention is formed on one side of the base film, and then the second adhesive layer is formed on the other side of the base film. Both adhesive layers can be formed by applying (coating) an adhesive layer composition to the surface of the base film, followed by drying or heating.

[0108] The adhesive layer composition may be a solution in which the inorganic particles, organic particles, resin, crosslinking agent, and other components are dispersed or dissolved in a solvent (e.g., water). The total solids concentration of the adhesive layer composition may be set depending on the type of components, solubility, coating viscosity, wettability, thickness after coating, etc. To obtain an adhesive layer with high surface uniformity, the total solids 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 the solvent.

[0109] The viscosity of the adhesive layer composition may be any appropriate viscosity within the range that allows coating. The viscosity, measured at 23°C and a shear rate of 1000 [1 / s], is preferably in the range of 1 to 50 [mPa·sec], and more preferably in the range of 2 to 10 [mPa·sec]. If the viscosity is within this range, an adhesive layer with excellent surface uniformity can be formed.

[0110] The adhesive layer composition can be prepared by any method. For example, a commercially available solution or dispersion may be used, a commercially available solution or dispersion may be used by adding a solvent, or a solid content may be dissolved or dispersed in various solvents.

[0111] Any method may be used as a method for applying (coating) the adhesive layer composition, for example, a method using gravure or a die coater. When applying the adhesive layer to the substrate film, the surface of the substrate film may be subjected to a pretreatment such as a modification treatment with a solvent, a corona treatment, or a plasma treatment to improve wettability.

[0112] (2.3) Substrate Film The substrate film according to the present invention contains a thermoplastic resin, and the thermoplastic resin contains at least a cycloolefin resin (cyclic olefin resin). The inclusion of a cycloolefin resin in the substrate film makes it easier to control the stretchability and crystallinity, and good adhesion can be ensured. The substrate film may be subjected to a surface modification treatment after production. Furthermore, the substrate film may contain a thermoplastic resin other than the cycloolefin resin as a resin, and may contain a plasticizer, optional components, and the like as additives.

[0113] The retardation value of the substrate film according to the present invention is in the range of 0 to 10 nm. Here, in this specification, "retardation value" refers to an in-plane retardation value. The "in-plane retardation value" is an index showing the degree of birefringence in the in-plane direction of a refractive index anisotropic body, and is a value expressed by the following formula, where Nx is the refractive index in the slow axis direction in which the refractive index is greatest in the in-plane direction, Ny is the refractive index in the fast axis direction perpendicular to the slow axis direction, and d is the thickness in the direction perpendicular to the in-plane direction of the refractive index anisotropic body.

[0114] Re[nm]=(Nx-Ny)×d[nm]

[0115] The in-plane retardation value (Re value) can be measured by the parallel Nicol rotation method using, for example, a KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. The in-plane retardation value of a microscopic area can also be measured using a Mueller matrix with an AxoScan manufactured by AXOMETRICS, Inc. (USA). In this specification, unless otherwise specified, the in-plane retardation value means the value at a wavelength of 550 nm.

[0116] (2.3.1) Resins Contained in the Base Film (Cycloolefin Resin) Examples of cycloolefin resins (cyclic olefin resins) include the following cycloolefin resins (hereinafter also referred to as "COP").

[0117] The cycloolefin resin is preferably a polymer of a cycloolefin monomer or a copolymer of a cycloolefin monomer and another copolymerizable monomer.

[0118] [Structure: General Formula (A-1) and General Formula (A-2)] The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and more preferably a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2).

[0119]

[0120] In general formula (A-1), R １ ~R ４each independently represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group, and p represents an integer of 0 to 2. １ ~R ４ do not all represent hydrogen atoms at the same time, and R １ and R ２ does not simultaneously represent a hydrogen atom, and R ３ and R ４ does not simultaneously represent a hydrogen atom.

[0121] 《R １ ~R ４ In general formula (A-1), R １ ~R ４ The hydrocarbon group having 1 to 30 carbon atoms represented by the formula (I) is preferably a hydrocarbon group having 1 to 10 carbon atoms, and more preferably a hydrocarbon group having 1 to 5 carbon atoms. The hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom. Examples of such linking groups include divalent polar groups such as a carbonyl group, an imino group, an ether bond, a silyl ether bond, and a thioether bond. Examples of the hydrocarbon group having 1 to 30 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group.

[0122] In general formula (A-1), R １ ~R ４ Examples of the polar group represented by the formula (I) include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group, and a cyano group. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group, and an aryloxycarbonyl group are preferred, and an alkoxycarbonyl group and an aryloxycarbonyl group are more preferred from the viewpoint of ensuring solubility during solution casting.

[0123] <> In general formula (A-1), p is preferably 1 or 2, from the viewpoint of improving the heat resistance of the film. When p is 1 or 2, the obtained polymer becomes bulky, and the glass transition temperature is likely to be improved.

[0124]

[0125] In general formula (A-2), R ５ represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. ６ represents a carboxy group, a hydroxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amido group, a cyano group, or a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), and p represents an integer of 0 to 2.

[0126] 《R ５ and R ６ R in general formula (A-2) ５ R in general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, and more preferably represents a hydrocarbon group having 1 to 3 carbon atoms. ６ preferably represents a carboxy group, a hydroxy group, an alkoxycarbonyl group or an aryloxycarbonyl group, and more preferably an alkoxycarbonyl group or an aryloxycarbonyl group from the viewpoint of ensuring solubility during solution casting.

[0127] <> p in formula (A-2) is the same as p in formula (A-1).

[0128] Cycloolefin monomers having a structure represented by general formula (A-2) are preferred from the viewpoint of improving solubility in organic solvents. In general, breaking the symmetry of an organic compound reduces the crystallinity, thereby improving the solubility in organic solvents. R in general formula (A-2) ５ and R ６ is substituted on only one ring-constituting carbon atom with respect to the axis of symmetry of the molecule, the molecule has low symmetry. In other words, a cycloolefin monomer having a structure represented by general formula (A-2) has high solubility and is therefore suitable for producing the substrate film of the present invention by a solution casting method.

[0129] The content of the cycloolefin monomer having the structure represented by general formula (A-2) in the polymer of cycloolefin monomers can be, for example, 70 mol% or more, preferably 80 mol% or more, and more preferably 100 mol% relative to the total of all cycloolefin monomers constituting the cycloolefin resin. When a certain amount or more of the cycloolefin monomer having the structure represented by general formula (A-2) is contained, the orientation of the resin is enhanced, and therefore the phase difference (retardation) value is likely to increase.

[0130] Specific examples of cycloolefin monomers having a structure represented by general formula (A-1) are shown below as Exemplary Compounds 1 to 14, and specific examples of cycloolefin monomers having a structure represented by general formula (A-2) are shown below as Exemplary Compounds 15 to 34.

[0131]

[0132] Examples of the copolymerizable monomer copolymerizable with the cycloolefin monomer include a copolymerizable monomer capable of ring-opening copolymerization with the cycloolefin monomer, and a copolymerizable monomer capable of addition copolymerization with the cycloolefin monomer.

[0133] Examples of copolymerizable monomers capable of ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

[0134] Examples of copolymerizable monomers capable of addition copolymerization include unsaturated double bond-containing compounds, vinyl-based cyclic hydrocarbon monomers, and (meth)acrylates. Examples of unsaturated double bond-containing compounds include olefin-based compounds having 2 to 12 carbon atoms (preferably 2 to 8), examples of which include ethylene, propylene, and butene. Examples of vinyl-based cyclic hydrocarbon monomers include vinylcyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of (meth)acrylates include alkyl (meth)acrylates having 1 to 20 carbon atoms, such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0135] The content of the cycloolefin monomer in the copolymer of a cycloolefin monomer and a copolymerizable monomer can be, for example, in the range of 20 to 80 mol %, preferably in the range of 30 to 70 mol %, based on the total of all monomers constituting the copolymer.

[0136] As described above, the cycloolefin resin is a polymer obtained by polymerizing or copolymerizing a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by general formula (A-1) or (A-2), and examples thereof include the following polymers (1) to (7):

[0137] (1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymer of cycloolefin monomer and copolymerizable monomer capable of ring-opening copolymerization therewith (3) Hydrogenated product of ring-opening (co)polymer of (1) or (2) above (4) Ring-opening (co)polymer of (1) or (2) above cyclized by Friedel-Crafts reaction, followed by hydrogenation (co)polymer (5) Saturated copolymer of cycloolefin monomer and unsaturated double bond-containing compound (6) Addition copolymer of cycloolefin monomer and vinyl cyclic hydrocarbon monomer, and hydrogenated product thereof (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate

[0138] The polymers (1) to (7) above can all be obtained by known methods, for example, the methods described in JP-A-2008-107534 and JP-A-2005-227606.

[0139] Catalysts and solvents used in the ring-opening copolymerization (2) above can be, for example, those described in paragraphs

[0019] to

[0024] of JP-A-2008-107534. Catalysts used in the hydrogenated products (3) and (6) above can be, for example, those described in paragraphs

[0025] to

[0028] of JP-A-2008-107534. Acidic compounds used in the Friedel-Crafts reaction (4) above can be, for example, those described in paragraph

[0029] of JP-A-2008-107534. Catalysts used in the addition polymerizations (5) to (7) above can be, for example, those described in paragraphs

[0058] to

[0063] of JP-A-2005-227606. The alternating copolymerization reaction (7) above can be carried out, for example, by the method described in paragraphs

[0071] and

[0072] of JP-A-2005-227606.

[0140] Among these, the polymers (1) to (3) and (5) are preferred, and the polymers (3) and (5) are more preferred.

[0141] [Structure: General Formula (B-1) and General Formula (B-2)] In other words, the cycloolefin resin preferably contains at least one of a structural unit represented by the following general formula (B-1) and a structural unit represented by the following general formula (B-2), in order to increase the glass transition temperature and light transmittance. It is more preferable that the cycloolefin resin contains only a structural unit represented by general formula (B-2), or contains both a structural unit represented by general formula (B-1) and a structural unit represented by general formula (B-2).

[0142] The structural unit represented by general formula (B-1) is a structural unit derived from a cycloolefin monomer represented by the above-mentioned general formula (A-1), and the structural unit represented by general formula (B-2) is a structural unit derived from a cycloolefin monomer represented by the above-mentioned general formula (A-2).

[0143]

[0144] In the general formula (B-1), X is —CH═CH— or —CH ２ CH ２ - represents. １ ~R ４ and p are R in general formula (A-1), １ ~R４ and p.

[0145]

[0146] In the general formula (B-2), X is —CH═CH— or —CH ２ CH ２ - represents. ５ ~R ６ and p are R in general formula (A-2), ５ ~R ６ and p.

[0147] [Content] The content of the cycloolefin resin is preferably 70% by mass or more, and more preferably 80% by mass or more, based on the base film of the present invention.

[0148] [Others] The cycloolefin resin according to the present invention may be a commercially available product. Examples of commercially available cycloolefin resins include Arton G (e.g., G7810), Arton F, Arton R (e.g., R4500, R4900, and R5000), and Arton RX, all manufactured by JSR Corporation.

[0149] The intrinsic viscosity [η]inh of the cycloolefin resin is 0.2 to 5 cm when measured at 30°C. ３ / g, and 0.3 to 3 cm ３ / g, and more preferably in the range of 0.4 to 1.5 cm ３ It is more preferable that the range is 1 / g.

[0150] The number average molecular weight (Mn) of the cycloolefin resin is preferably in the range of 8,000 to 100,000, more preferably in the range of 10,000 to 80,000, and even more preferably in the range of 12,000 to 50,000.

[0151] The weight average molecular weight (Mw) of the cycloolefin resin is preferably in the range of 20,000 to 300,000, more preferably in the range of 30,000 to 250,000, and even more preferably in the range of 40,000 to 200,000.

[0152] The number average molecular weight and weight average molecular weight of the cycloolefin resin can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0153] Gel Permeation Chromatography Solvent: Methylene chloride Column: Shodex K806, K805, K803G (three columns manufactured by Showa Denko K.K. were connected and used) Column temperature: 25°C Sample concentration: 0.1% by mass Detector: RI Model 504 (manufactured by GL Sciences) Pump: L6000 (manufactured by Hitachi, Ltd.) Flow rate: 1.0 ml / min Calibration curve: A calibration curve was prepared using 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) with Mw ranging from 500 to 2,800,000. It is preferable to use the 13 samples at approximately equal intervals.

[0154] When the intrinsic viscosity [η]inh, number average molecular weight and weight average molecular weight are within the above ranges, the cycloolefin resin has good heat resistance, water resistance, chemical resistance, mechanical properties and moldability into a film.

[0155] The glass transition temperature (Tg) of the cycloolefin resin is usually 110°C or higher, preferably in the range of 110 to 350°C, more preferably in the range of 120 to 250°C, and even more preferably in the range of 120 to 220°C. When the glass transition temperature (Tg) is 110°C or higher, deformation under high temperature conditions is easily suppressed. On the other hand, when the glass transition temperature (Tg) is 350°C or lower, molding processing is facilitated and deterioration of the resin due to heat during molding processing is also easily suppressed. A more preferred range is 140 to 200°C.

[0156] (Other Thermoplastic Resins) As thermoplastic resins other than the cycloolefin resin (cyclic olefin resin) according to the present invention, for example, cellulose ester resins, polypropylene resins, acrylic resins, polyester resins, etc. can be applied. Examples of cellulose ester resins include triacetyl cellulose (TAC), cellulose acetate propionate (CAP), diacetyl cellulose (DAC), etc. Examples of polypropylene resins include polypropylene (PP), etc. Examples of acrylic resins include polymethyl methacrylate (PMMA), etc. Examples of polyester resins include polyethylene terephthalate (PET), etc.

[0157] (2.3.2) Plasticizer The substrate film according to the present invention preferably contains at least one plasticizer, for example, for the purpose of imparting processability. The plasticizers are preferably used alone or in combination. Among these plasticizers, it is preferred to contain at least one plasticizer selected from the group consisting of sugar esters, polyesters, and styrene-based compounds, from the viewpoint of effectively controlling moisture permeability and achieving high compatibility with substrate resins such as cellulose esters.

[0158] The molecular weight of the plasticizer is preferably 15,000 or less, and even more preferably 10,000 or less, from the viewpoint of achieving both improved moist heat resistance and compatibility with base resins such as cellulose esters. When the compound having a molecular weight of 10,000 or less is a polymer, it preferably has a weight-average molecular weight (Mw) of 10,000 or less. A preferred weight-average molecular weight (Mw) range is 100 to 10,000, and more preferably 400 to 8,000. In particular, the compound having a molecular weight of 1,500 or less is preferably contained in an amount of 6 to 40 parts by weight, and more preferably 10 to 20 parts by weight, per 100 parts by weight of the base resin. By containing the compound within such a range, effective control of moisture permeability and compatibility with the base resin can be achieved, which is preferable.

[0159] (Sugar Ester) The base film according to the present invention may contain a sugar ester compound for the purpose of preventing hydrolysis. Specifically, the sugar ester compound may be a sugar ester having 1 to 12 pyranose or furanose structures, in which all or part of the OH groups in the structure have been esterified.

[0160] (Polyester) The base film according to the present invention may contain a polyester. The polyester is not particularly limited. For example, a polymer (polyester polyol) having a terminal hydroxy group, which can be obtained by a condensation reaction between a dicarboxylic acid or an ester-forming derivative thereof and a glycol, can be used. Alternatively, a polymer (terminal-capped polyester) in which the terminal hydroxy group of the polyester polyol is capped with a monocarboxylic acid can be used. The ester-forming derivative referred to here refers to an esterified product of a dicarboxylic acid, a dicarboxylic acid chloride, or an anhydride of a dicarboxylic acid.

[0161] (Styrene-based Compound) In addition to or instead of the sugar ester and polyester, a styrene-based compound may also be used in the base film according to the present invention for the purpose of improving water resistance.

[0162] The styrene-based compound may be a homopolymer of a styrene-based monomer or a copolymer of a styrene-based monomer and another copolymerizable monomer. The content of the structural unit derived from the styrene-based monomer in the styrene-based compound may be preferably in the range of 30 to 100 mol %, more preferably in the range of 50 to 100 mol %, so that the molecular structure has a certain level of bulkiness.

[0163] Examples of styrene-based monomers include styrene; alkyl-substituted styrenes such as α-methylstyrene, β-methylstyrene, and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrenes such as p-hydroxystyrene, α-methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, and 3,4-dihydroxystyrene; vinylbenzyl alcohols; alkoxy-substituted styrenes such as p-methoxystyrene, p-tert-butoxystyrene, and m-tert-butoxystyrene; 3-vinylbenzoic acid, 4-vinylbenzoic acid, and the like. Examples of the styrene-based monomer include vinyl benzoates such as benzoic acid, 4-vinylbenzyl acetate, 4-acetoxystyrene, amidostyrenes such as 2-butylamidostyrene, 4-methylamidostyrene, and p-sulfonamidostyrene, aminostyrenes such as 3-aminostyrene, 4-aminostyrene, 2-isopropenylaniline, and vinylbenzyldimethylamine, nitrostyrenes such as 3-nitrostyrene and 4-nitrostyrene, cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene, vinylphenylacetonitrile, arylstyrenes such as phenylstyrene, and indenes. The styrene-based monomer may be one type, or two or more types may be combined.

[0164] (2.3.3) Optional Components The substrate film according to the present invention may contain other optional components, such as antioxidants, colorants, UV absorbers, fine particles, etc. These components may be added in an amount of 0.01 to 20 parts by mass per 100 parts by mass of the substrate resin.

[0165] (Antioxidant) Conventionally known antioxidants can be used in the base film of the present invention. In particular, lactone-based, sulfur-based, phenol-based, double bond-based, hindered amine-based, and phosphorus-based compounds are preferably used. These antioxidants are added in an amount of 0.05 to 20% by mass, preferably 0.1 to 1% by mass, based on the resin that is the main raw material of the base film. A synergistic effect can be achieved by using several different types of antioxidants in combination, rather than using only one type. For example, a combination of lactone-based, phosphorus-based, phenol-based, and double bond-based compounds is preferred.

[0166] (Colorant) The substrate film according to the present invention preferably contains a colorant for adjusting the color tone, within a range that does not impair the effects of the present invention. The colorant refers to a dye or pigment, and in the present invention refers to a colorant that has the effect of making the color tone of the liquid crystal screen bluer, adjusting the yellow index, or reducing haze. Various dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments, etc. are effective.

[0167] (UV Absorber) The substrate film according to the present invention may contain an UV absorber for the purpose of imparting UV absorption functionality. The UV absorber is not particularly limited, but examples include benzotriazole-based, 2-hydroxybenzophenone-based, and salicylic acid phenyl ester-based UV absorbers. Examples include triazoles such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, and 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, and benzophenones such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone. The UV absorbers may be used alone or in combination. The amount of the ultraviolet absorber used varies depending on the type of ultraviolet absorber, the conditions of use, etc., but is generally added in the range of 0.05 to 10% by mass, preferably 0.1 to 5% by mass, relative to the base resin.

[0168] (Microparticles) It is preferable to add microparticles that impart slipperiness to the substrate film of the present invention. In particular, adding microparticles is effective from the viewpoint of improving the slipperiness of the surface of the substrate film of the present invention, improving the slipperiness during winding, and preventing the occurrence of scratches and blocking. As the microparticles, either inorganic or organic microparticles may be used as long as they do not impair the transparency of the obtained substrate film and are heat resistant during melting, but inorganic microparticles are more preferred. These microparticles can be used alone or in combination of two or more types. By using particles with different particle sizes and shapes (e.g., acicular and spherical), it is also possible to achieve both high transparency and slipperiness.

[0169] Among the compounds constituting the above-mentioned fine particles, silicon dioxide is particularly preferably used, since it has a refractive index close to that of the cycloolefin resin, acrylic resin, or cellulose ester resin, and therefore has excellent transparency (haze prevention).Specific examples of silicon dioxide include Aerosil (registered trademark) 200V, Aerosil (registered trademark) R972V, Aerosil (registered trademark) R972, R974, R812, 200, 300, R202, OX50, TT600, and NAX50 (all manufactured by Nippon Aerosil Co., Ltd.), Seahoster (registered trademark) KEP-10, Seahoster (registered trademark) KEP-30, and Seahoster (registered trademark) KEP-50 (all manufactured by Nippon Shokubai Co., Ltd.), Silohobic (registered trademark) 100 (manufactured by Fuji Silysia Co., Ltd.), Nipsil (registered trademark) E220A (manufactured by Nippon Silica Industry Co., Ltd.), and Admafine (registered trademark) SO (manufactured by Admatechs Co., Ltd.).

[0170] The particle shape can be any shape, including amorphous, acicular, flat, and spherical, and is particularly preferred since it improves the transparency of the resulting substrate film. The particle size is preferably smaller than the wavelength of visible light, and more preferably 1 / 2 or less of the wavelength of visible light, since light scattering occurs when the particle size is close to the wavelength of visible light, resulting in poor transparency. If the particle size is too small, the slipperiness may not be improved, so a particle size within the range of 80 to 180 nm is particularly preferred. Note that, when the particles are aggregates of primary particles, the particle size refers to the size of the aggregate. Furthermore, when the particles are not spherical, the particle size refers to the diameter of a circle equivalent to the projected area of ​​the particles.

[0171] The fine particles are preferably added in an amount of 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass, based on the base resin.

[0172] (2.3.4) Thickness of the Base Film The thickness of the base film according to the present invention is in the range of 5 to 29 μm. If the thickness of the base film is 5 μm or more, the rigidity is increased and it becomes easier to maintain the shape. Furthermore, if the thickness of the base film is 29 μm or less, the mass does not increase too much, making it easier to produce a long base film. The thickness of the base film according to the present invention can be measured in the same manner as for the carrier film described above. It is more preferably in the range of 10 to 20 μm.

[0173] 3. Cured Layer The laminate film of the present invention has multiple cured layers, beads are contained between the cured layers, and the multiple cured layers have different refractive indices. Each cured layer contains a binder resin and may contain particles to increase the refractive index. Other additives may also be contained within a range that does not impair these functions. In this case, it is preferable from the perspective of improving light extraction performance that the refractive index of the multiple cured layers gradually increases from the substrate side toward the outermost layer. Note that the "outermost layer" of the multiple cured layers refers to the outermost cured layer located on the opposite side of the multiple cured layers from the substrate film.

[0174] As described above, Fig. 2 is an example of a schematic structural diagram of a laminate film of the present invention when the cured layer of the laminate film has a three-layer structure. When beads are contained between the multiple cured layers, this includes cases where the beads are contained between the multiple cured layers, i.e., across the interfaces of the multiple cured layers, as shown in Figs. 2A, 2B, 2C, and 2D. When beads are contained between the multiple cured layers, the beads do not protrude from the cured layer L3 but are embedded in the multiple cured layers.

[0175] (3.1) Refractive index of cured layer The multiple cured layers included in the laminate film of the present invention have a refractive index difference. In this case, the refractive index difference between the multiple cured layers is preferably 0.02 or more, more preferably 0.05 or more. Furthermore, either the refractive index of the binder resin or the refractive index of the beads may be higher, but from the viewpoint of improving light extraction efficiency, it is preferable that the absolute value of the difference between the two refractive indices is within the range of 0.01 to 0.05.

[0176] Examples of combinations in which the absolute value of the refractive index difference between the binder resin and the beads falls within the above range include the following combinations: Note that the values ​​in parentheses below are the refractive indices of the materials.

[0177] "Binder resin: acrylic resin (1.50)" and "Beads: acrylic resin particles (1.49)", "Binder resin: acrylic resin (1.50)" and "Beads: nylon resin particles (1.53)", and "Binder resin: epoxy resin (1.55)" and "Beads: polyethylene resin particles (1.53)".

[0178] (Method of Measurement) The refractive index of the cured layer according to the present invention can be measured, for example, by forming the cured layer alone and then using an Abbe refractometer (NAR-4T manufactured by Atago Co., Ltd.) or an ellipsometer.

[0179] The refractive index of the cured layer can be measured even after the cured layer is formed into a laminate film, and for example, the Becke method according to JIS K 7142:2008 Method B (for powder or granular transparent materials) can be used. Measurement by the Becke method can be performed, for example, as follows.

[0180] The cured layers in the laminated film containing the cured layer are each scraped off with a cutter or the like to prepare a powder sample, which is placed on a slide glass. Cargill reagent with a known refractive index is dropped onto the sample, immersing the sample, and the state of the sample is observed under a microscope.

[0181] Here, bright lines (Becke lines) appear on the sample contour due to the difference in refractive index between the sample and the Cargill reagent. Utilizing this, the refractive index of the reagent at which the bright lines (Becke lines) become invisible is measured, and this is taken as the refractive index of the sample, i.e., the refractive index of the cured layer.

[0182] (3.2) Beads contained in the cured layer As mentioned above, the "beads" according to the present invention refer to particulate fillers contained in order to improve the light diffusion properties, transparency, etc. of a molded article such as the cured layer. The shape of the beads is a particle having any geometric shape such as a spherical, cylindrical, or lumpy shape, and does not necessarily have to be a spherical particle with a hole. In the present invention, it is particularly preferable to use resin particles.

[0183] When resin particles (organic particles) are used as the beads according to the present invention, the light transmittance is higher than that of inorganic particles, and the light absorption by the particles is extremely low. Therefore, by including the beads between multiple cured layers, the light utilization efficiency of the multiple cured layers is improved overall.

[0184] Examples of beads according to the present invention include silicone resin particles, acrylic resin particles, nylon resin particles, styrene resin particles, styrene-acrylic resin particles, polyethylene particles, benzoguanamine resin particles, urethane resin particles, and melamine resin particles.

[0185] Examples of commercially available products include the following: Acrylic acid ester-styrene copolymer, refractive index: 1.53, number average particle size: 8 μm (manufactured by Aica Kogyo, trade name Ganz Pearl GM-0853S) Acrylic acid ester-styrene copolymer, refractive index: 1.55, number average particle size: 8 μm (manufactured by Aica Kogyo, trade name Ganz Pearl GM-0855S) Polymethylsilsesquioxane, refractive index: 1.41, number average particle size: 4 μm (manufactured by Aica Kogyo, trade name Ganz Pearl SI-045) Polyacrylic acid ester, refractive index: 1.49, number average particle size: 8 μm (manufactured by Aica Kogyo, trade name Ganz Pearl GM-0855S) Polystyrene, refractive index: 1.59, number average particle size: 11 μm (manufactured by Aica Kogyo, trade name Ganz Pearl GS-1105)

[0186] (Average particle size of beads) The average particle size of the beads according to the present invention is preferably relatively small, specifically within the range of 3 to 6 μm. This allows the surface of the cured layer to have fine convex portions of about several μm, thereby improving the viewing angle dependency. In this specification, the "average particle size" refers to a value calculated by the Coulter counter method.

[0187] (Bead Content) The content of beads in the cured layer according to the present invention is preferably 100 parts by mass or more, more preferably 120 parts by mass or more, per 100 parts by mass of binder resin. By adjusting the content of beads relative to the binder resin in this manner, viewing angle dependency can be improved. Furthermore, the content of beads is preferably 160 parts by mass or less per 100 parts by mass of binder resin, which can suppress a decrease in light extraction efficiency.

[0188] (3.3) Particles for increasing the refractive index of the cured layer In addition to beads, the cured layer according to the present invention can contain particles for increasing the refractive index (hereinafter also referred to as "high refractive index fine particles"). This makes it possible to increase the refractive index of the cured layer to more than 1.49, making it a high refractive index layer. As mentioned above, for convenience in this specification, a cured layer having a refractive index greater than 1.49 is referred to as a high refractive index layer, and a cured layer having a refractive index of 1.49 or less is referred to as a low refractive index layer.

[0189] For example, inorganic particles are used as the high refractive index fine particles. Examples of such inorganic particles include metal oxide particles. Specific examples of such metal oxide particles include the following. Note that the values ​​in parentheses below are the refractive indexes of the materials.

[0190] Titanium oxide: TiO ２ (2.3 to 2.7), niobium oxide: Nb ２ O ５ (2.33), zirconium oxide: ZrO ２ (2.10), antimony oxide: Sb ２ O ５ (2.04), tin oxide: SnO ２(2.00), tin-doped indium oxide: ITO (1.95-2.00), cerium oxide: CeO ２ (1.95), aluminum-doped zinc oxide: AZO (1.90-2.00), gallium-doped zinc oxide: GZO (1.90-2.00), zinc antimonate: ZnSb ２ O ６ (1.90-2.00), zinc oxide: ZnO (1.90), yttrium oxide: Y ２ O ３ (1.87), antimony-doped tin oxide: ATO (1.75 to 1.85), and phosphorus-doped tin oxide: PTO (1.75 to 1.85).

[0191] Among the above metal oxide particles, zirconium oxide: ZrO ２ It is preferable that the refractive index is (2.10) from the viewpoint of increasing the refractive index and cost.

[0192] (Average Particle Diameter) The average particle diameter of the high refractive index fine particles is preferably within the range of, for example, 5 to 50 nm.

[0193] (Content) The content of the high refractive index fine particles is preferably within the range of, for example, 20 to 95% by mass.

[0194] (3.4) Binder Resin of Cured Layer The binder resin is not particularly limited, but examples thereof include thermoplastic resins, thermosetting resins, and photocurable resins.

[0195] From the viewpoint of increasing the surface hardness, the binder resin is preferably a polymer or copolymer of a thermally polymerizable monomer or a photopolymerizable monomer, etc. Among these, a polymer of a photopolymerizable monomer is more preferred.

[0196] (Thermoplastic Resin) Examples of the thermoplastic resin include cellulose ester resins such as triacetyl cellulose, cellulose acetate propionate, and diacetyl cellulose. In addition, 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 are also applicable.

[0197] (Thermosetting Resin) Examples of the thermosetting resin include acrylic resin, urethane resin, phenolic resin, urea melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, etc. The thermosetting resin may be cured by heat or by a method using a curing agent.

[0198] (Photocurable Resin) The compound constituting the photopolymerizable resin is not particularly limited, and 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 higher functional 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, or the like.

[0199] Furthermore, these compounds may be those in which an aromatic ring, a halogen atom other than fluorine, sulfur, nitrogen, phosphorus atom or the like is introduced to adjust the refractive index to a high level.

[0200] In addition to the above compounds, resins composed of relatively low molecular weight monomers having unsaturated double bonds can also be used, such as polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiolpolyene resins.

[0201] When polymerizing (crosslinking) the photopolymerizable monomer, a polymerization initiator or the like may be used. The polymerization initiator is a component that is decomposed by light irradiation to generate radicals and initiate or advance the polymerization (crosslinking) of the photopolymerizable compound.

[0202] (3.5) Other Additives, etc. In addition to the beads, particles for increasing the refractive index (high refractive index fine particles), and binder resin described above, the cured layer according to the present invention may contain other additives, etc., to the extent that the functions of these additives are not impaired. Examples of other additives include conventionally known dispersants, surfactants, antistatic agents, silane coupling agents, thickeners, coloring inhibitors, colorants (pigments, dyes), defoamers, leveling agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, and lubricants.

[0203] (3.6) Thickness of the Cured Layer The thickness of the cured layer according to the present invention is preferably within a range of 3 to 30 μm because it is preferable that the beads do not protrude from the outermost layer, and is also preferably within a range of 3 to 15 μm from the viewpoint of easily preventing curling. The thickness of the cured layer according to the present invention can be measured by the same method as for the carrier film described above.

[0204] (3.7) Method for Forming Cured Layer The cured layer according to the present invention can be formed, for example, by the following method: First, a coating liquid of a composition for cured layer is prepared by dissolving materials containing photopolymerizable compounds such as the above-mentioned beads, particles for increasing the refractive index (high refractive index fine particles), binder resins, and other additives in an appropriate solvent.

[0205] The coating solution is then applied and dried to form a coating film. The coating solution of the curable layer composition in the form of a coating film is then irradiated with light such as ultraviolet light to polymerize (crosslink) the photopolymerizable compound, thereby forming a cured layer. The content of the beads and particles for increasing the refractive index (high refractive index fine particles) in the coating solution is adjusted as needed.

[0206] The coating solution of the curable layer composition can be applied by any known coating method, such as spin coating, dipping, spraying, slide coating, bar coating, roll coating, gravure coating, and die coating.

[0207] The light used to cure the curable layer composition is not particularly limited, and examples thereof include ultraviolet light and electron beams. When ultraviolet light is used as the light, ultraviolet light emitted from an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. The wavelength of the ultraviolet light can be in the range of 190 to 380 nm. Specific examples of electron beam sources include various electron beam accelerators such as a Cockcroft-Waldt type, a Van de Graaf type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type.

[0208] The coating solution of the curable layer composition may contain a polymerization initiator as needed. Other additives may also be added depending on the purpose of increasing the hardness of the curable layer, suppressing cure shrinkage, and controlling the refractive index.

[0209] (Polymerization Initiator) The polymerization initiator is not particularly limited as long as it is capable of releasing a substance that initiates radical polymerization upon irradiation with light, and known polymerization initiators can be used. Specific examples of known initiators include acetophenones, benzophenones, Michler's benzoyl benzoate, α-amyloxime ester, thioxanthones, propiophenones, benzils, benzoins, and acylphosphine oxides. It is also preferable to use a mixture of the polymerization initiator and a photosensitizer; specific examples include n-butylamine, triethylamine, and poly-n-butylphosphine. When the binder resin contained in the cured layer is a resin system having a radically polymerizable unsaturated group, it is preferable to use acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc., alone or in combination, as the polymerization initiator.

[0210] [II. Method for producing laminated film] The method for producing a laminated film of the present invention is a method for producing a laminated film of the present invention, and is characterized by comprising a step of measuring the heat shrinkage rate of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer under conditions of 130°C for 90 minutes, and adjusting the heat shrinkage rates in the longitudinal direction and the width direction to satisfy the following formulas (1) and (2), where X and Y are the heat shrinkage rates in the longitudinal direction and the width direction, respectively.

[0211] Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%]

[0212] The process for producing the laminated film of the present invention is carried out by first forming a laminate portion and then forming multiple cured layers on the laminate portion, and then forming a base film and then forming a second adhesive layer and a first adhesive layer on the base film.

[0213] 3 is a flowchart showing the flow of the manufacturing process of the laminated film of the present invention. Note that the carrier film according to the present invention is attached to the first adhesive layer after the first adhesive layer is formed in the first adhesive layer forming step in FIG.

[0214] 4. Preparation of Substrate Film The substrate film according to the present invention is a substrate film containing a cycloolefin resin. The substrate film can be prepared by, for example, a solution casting method or a melt casting method, and the preparation process comprises a step of preparing a raw film and a step of processing the raw film. Hereinafter, the process of preparing the substrate film by the solution casting method will be described first, and then the process of preparing the substrate film by the melt casting method will be described.

[0215] (4.1) Solution Casting Film Formation Method The "solution casting film formation method" is a film formation method as follows. First, a dope is cast onto a moving support to form a casting film (web), which is then dried to a degree that allows peeling. Then, the web is peeled off from the support as a film, and the peeled film is dried and stretched while being transported by a transport roller to form a long resin film.

[0216] In the process for producing a substrate film by the solution casting film-forming method according to the present invention, the process for producing a raw film comprises at least the following three steps (A), (B), and (C).

[0217] (A) A step of casting the dope onto a support to form a web; (B) A step of performing the first stage of stretching; and (C) A step of drying the web to form a film and winding it up.

[0218] The raw film processing step is a step of transporting the wound raw film and performing a second stage of stretching.

[0219] In the step of subjecting the wound film to the second-stage stretching, the amount of residual solvent immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass relative to the winding width.

[0220] FIG. 4 is a flow chart showing the flow of steps for producing a substrate film by the solution casting method, and FIG. 5 is a schematic diagram of an apparatus for producing a substrate film by the solution casting method.

[0221] (4.1.1) Preparation of Raw Film The process for preparing the raw film comprises at least the steps of (A) casting the dope onto a support to form a web, (B) performing the first stage of stretching, and (C) drying the web to form a film and winding it up.

[0222] (A) Step of Casting Dope onto Support to Form Web The step of casting a dope onto a support to form a web comprises at least a dope preparation step (S1), a casting step (S2), and a peeling step (S3).

[0223] (A-1) Dope Preparation Step (S1) In the dope preparation step (S1) (also referred to as "stirring preparation step"), at least a resin and a solvent are stirred in a stirring tank 1a of a stirring device 1 to prepare a dope to be cast onto a support 3 (endless belt) (see FIG. 5). In the preparation of the substrate film according to the present invention, a cycloolefin resin (hereinafter also referred to as "COP"), which is a thermoplastic resin, is used as the resin.

[0224] In this step, the COP is dissolved in a solvent mainly consisting of a good solvent for the COP while stirring in a dissolving vessel to form a dope. In some cases, the COP and other compounds may be mixed in the dissolving vessel to prepare the dope, which is the main solution.

[0225] <COP Concentration> The concentration of COP in the dope is preferably high from the viewpoint of reducing the drying load after casting the dope onto a support, but if the concentration is too high, the load during filtration increases, resulting in poor accuracy. Therefore, from the viewpoint of achieving both a reduction in the drying load and a reduction in accuracy due to an increase in the load during filtration, the concentration of COP in the dope is preferably in the range of 10 to 35% by mass, more preferably in the range of 15 to 30% by mass.

[0226] <Solvent> The above solvents may be used alone 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 COPs. From the viewpoint of solubility of COPs, it is preferable to use a large amount of good solvent. Furthermore, it is preferable that water is contained in the dope in a range of 0.01 to 2.00 mass %. The mixing ratio of the good solvent to the poor solvent is preferably in a range of 70 to 98 mass % for the good solvent and in a range of 2 to 30 mass % for the poor solvent.

[0227] In this specification, a "good solvent" is defined as one that dissolves the COP used alone. A "poor solvent" is defined as one that swells or does not dissolve the COP alone. Therefore, whether a solvent is a good solvent or a poor solvent may vary depending on the type and number of substituents on the COP. The good solvent is not particularly limited, but examples include organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate. Of these, methylene chloride or methyl acetate is particularly preferred. The poor solvent is not particularly limited, but examples of preferred solvents include methanol, ethanol, n-butanol, cyclohexane, and cyclohexanone.

[0228] The solvent may be recovered and reused after being removed from the substrate film by drying during the production process of the substrate film. The recovered solvent may contain trace amounts of additives such as plasticizers, ultraviolet absorbers, polymers, and monomer components, but it can be preferably reused even if it contains these. If necessary, it can also be purified and reused.

[0229] <Dissolution Method> A common method can be used to dissolve COPs in the dope preparation. Specifically, a method under normal pressure, a method under a pressure equal to or lower than the boiling point of the main solvent, or a method under pressure equal to or higher than the boiling point of the main solvent is preferred. Furthermore, a combination of heating and pressurization can be used to heat the mixture to a temperature equal to or higher than the boiling point at normal pressure. A cooling dissolution method is also preferred, by which COPs can be dissolved in a solvent such as methyl acetate.

[0230] Furthermore, a method of stirring and dissolving while heating at a temperature equal to or higher than the boiling point of the solvent at normal pressure but within a range in which the solvent does not boil under pressure is also preferred, which can prevent the formation of lumpy undissolved matter called gel or lumpy matter.A method of mixing the COP with a poor solvent to wet or swell the COP, and then adding a good solvent to dissolve the COP is also preferred.

[0231] Pressurization may be achieved by injecting an inert gas such as nitrogen gas, or by increasing the vapor pressure of the solvent by heating. The pressure is adjusted so that the solvent does not boil at the set temperature. Heating is preferably performed externally, and a jacket-type heating system, for example, is preferred because it makes temperature control easier. The heating temperature after adding the solvent is preferably high from the viewpoint of solubility of the COP, but if the heating temperature is too high, the required pressure increases, resulting in poor productivity. Therefore, the heating temperature is preferably within the range of 30 to 120°C, more preferably within the range of 60 to 110°C, and even more preferably within the range of 70 to 105°C.

[0232] <Filtration> The dope can be filtered by a conventional method. However, a method of filtering while heating at a temperature above the boiling point of the solvent at normal pressure and within a range in which the solvent does not boil under pressure is preferred from the viewpoint of minimizing the increase in the difference in filtration pressure (referred to as differential pressure) before and after filtration. The temperature is preferably within a range of 30 to 120°C, more preferably within a range of 45 to 70°C, and even more preferably within a range of 45 to 55°C. A lower filtration pressure is preferred. Specifically, the filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and even more preferably 1.0 MPa or less. The dope during or after dissolution is preferably filtered using an appropriate filter material such as filter paper. Hereinafter, the "dope during or after dissolution" is also simply referred to as the "COP solution." From the viewpoint of removing insoluble matters, it is preferable to use a filter material with a low absolute filtration accuracy. However, a filter material with too low absolute filtration accuracy is prone to clogging during filtration. Therefore, the absolute filtration accuracy of the filter material is preferably 0.008 mm or less, more preferably within the range of 0.001 to 0.008 mm, and even more preferably within the range of 0.003 to 0.006 mm.

[0233] The material of the filter is not particularly limited, and a conventional filter can be used. From the viewpoint of preventing fiber shedding, for example, a filter made of a plastic such as polypropylene or Teflon (registered trademark), or a filter made of a metal such as stainless steel is preferred.

[0234] It is preferable to remove or reduce impurities, particularly bright spot foreign matter, contained in the raw material COP by filtration. "Bright spot foreign matter" refers to a spot (foreign matter) that appears as light leaking from the opposite side when, for example, two polarizing plates are arranged in a crossed Nicol state, a film or the like is placed between them, light is applied from one polarizing plate side, and the film is observed from the other polarizing plate side. The diameter of the bright spot foreign matter is preferably 0.01 mm or more, and it is also preferable to have fewer bright spots of 0.01 mm or less.

[0235] The number of bright spots is 200 / cm ２ The number of bright spots is preferably 100 / cm or less. ２ More preferably, it is 50 particles / cm or less. ２ or less, and more preferably 0 to 10 particles / cm ２ The following is the result.

[0236] (A-2) Casting Step (S2) In the casting step (S2), the conveying speed V １ The web 5 formed from the dope cast on the support 3 is heated on the support 3. This evaporates the solvent until the web 5 can be peeled off from the support 3 with a peeling roller 4, thereby controlling the amount of remaining solvent just before the first stage of stretching (see FIG. 5).

[0237] <Support> The support 3 preferably has a mirror-finished surface, and a stainless steel belt or a drum with a plated surface made of cast metal is preferably used. The support 3 is made of, for example, a stainless steel belt, and is held by a pair of rollers 3a, 3b and multiple rollers positioned between them. One or both of the rollers 3a and 3b is provided with a drive device that applies tension to the support 3, so that the support 3 is used in a tensioned state under tension. The support 3 may also be a drum.

[0238] The surface temperature of the support 3 is preferably high from the viewpoint of increasing the drying speed of the web, and is preferably, for example, a temperature within the range of -50°C to the boiling point of the solvent. The surface temperature of the support is more preferably within the range of 0 to 55°C, and even more preferably within the range of 22 to 50°C.

[0239] The method for controlling the surface temperature of the support 3 is not particularly limited, but examples thereof include a method of blowing hot or cold air, and a method of bringing hot water into contact with the back side of the support. Among these, the method of bringing hot water into contact with the back side of the support is preferred because heat transfer is efficient and the time required for the support temperature to become constant is short. When using the method of blowing hot air, air with a temperature higher than the target temperature may be used.

[0240] <Casting Die> In the casting step (S2), the dope prepared in the dope preparing step (S1) is fed through a conduit to a casting die 2 via a pressure type metering gear pump or the like. The dope is cast from the casting die 2 onto a casting position on a support 3 made of a stainless steel endless belt that is rotated and moves endlessly.

[0241] Casting dies include coat hanger dies and T-dies, and any of these is preferably used. To increase the film-forming speed of the raw film, two or more of the above-mentioned casting dies may be provided on the support, and the dope may be divided and layered. It is also preferable to obtain a raw film having a laminated structure by a co-casting method in which multiple dopes are simultaneously cast.

[0242] The casting die is provided with a mechanism for adjusting the width of a slit through which the dope is discharged (or the resin is extruded in the case of melting). The direction in which the dope is discharged from the casting die 2 to the support 3 is adjusted by the inclination of the casting die 2. The inclination of the casting die 2 may be set appropriately so that the angle with respect to the normal to the surface of the support 3 (the surface onto which the dope is cast) falls within the range of 0 to 90 degrees.

[0243] Here, the part of the casting die slit from which the dope comes out is called a lip, and a casting die that can adjust the slit shape of the lip and can easily make the thickness of the dope uniform when it is discharged is preferred. In the casting step (S2), the "web" refers to the dope film cast from the lip.

[0244] It is preferable to adjust the width of the slit through which the dope is discharged by the heat bolt of the casting die so that the thickness deviation of the casting film (web) immediately after discharge is within the range of 1.0 to 5.0% for the entire casting film (web), thereby controlling the initial film thickness of the casting film (web).

[0245] From the viewpoint of improving productivity, the casting width (also referred to as "cast width") is preferably 1.3 m or more, and more preferably in the range of 1.3 to 4.0 m. If the casting width does not exceed 4.0 m, streaks will not appear in the production process and the stability in the subsequent transport process will be improved. From the viewpoint of transportability and productivity, the casting width is preferably in the range of 1.3 to 3.0 m.

[0246] (A-3) Peeling Step (S3) In the peeling step (S3), the solvent is evaporated in the casting step (S2) until the web 5 has a film strength that allows it to be peeled off from the support 3, and the web is dried and solidified or cooled and solidified, and then the web is peeled off from the support 3 before the raw film makes one revolution around the support 3. That is, in this step, the web from which the solvent has been evaporated on the support 3 until it has a film strength that allows it to be peeled off is peeled off at the peeling position by a peeling roller 4 while maintaining its self-supporting properties. The roller that helps peel the web from the support is called a peeling roller.

[0247] The time required for peeling is preferably within a range of 30 to 600 seconds from the viewpoints of surface quality, moisture permeability, and peelability. The temperature at the peeling position on the support is preferably within a range of −50 to 40° C., more preferably within a range of 10 to 40° C., and most preferably within a range of 15 to 30° C.

[0248] <Residual Solvent Amount> The amount of residual solvent immediately before the first-stage stretching is adjusted as appropriate depending on the strength of the drying conditions, the length of the support 3, and the like. As a method for controlling this residual solvent amount, the evaporation is preferably carried out in an atmosphere within a range of 5 to 75°C. Examples of methods for evaporating the solvent include a method of applying hot air to the upper surface of the web, a method of transferring heat from the back surface of the support 3 using a liquid, and a method of transferring heat from both sides using radiant heat. Among these, a method of transferring heat from both sides using radiant heat is preferred from the viewpoint of improving drying efficiency. A combination of these methods is also preferably used.

[0249] Although it depends on the thickness of the web, if the amount of residual solvent at the peeling point (the position where the web is peeled from the support) is too high, the web may become too soft and difficult to peel. This may impair flatness, and horizontal steps, wrinkles, or vertical streaks may occur due to the peel tension. Conversely, if the amount of residual solvent is too low, part of the web may peel off during the process. In order for the web to exhibit good flatness, from the viewpoint of balancing economic speed and quality, 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.

[0250] The film formation rate can be increased by using a gel casting method in which the web is peeled off while the residual solvent content in the web is as high as possible. This method gels the web on the support, strengthens the film, and accelerates peeling, thereby increasing the film formation rate. Examples of methods include adding a poor solvent for COP to the dope and gelling the web after dope casting, cooling the support to gel the web and peeling it off while it contains a large amount of residual solvent, and adding a metal salt to the dope.

[0251] The residual solvent amount is defined by the following formula: Residual solvent amount (mass %)={(M-N) / N}×100 In the above formula, M is the mass of a sample taken at any time during or after the production of the web or base film, and N is the mass of M after heating at 115°C for 1 hour.

[0252] The amount of residual solvent can be measured by headspace gas chromatography. In this measurement, a sample is sealed in a container, heated, and the container is filled with volatile components. The gas in the container is then quickly injected into a gas chromatograph, where mass spectrometry is performed to identify the compounds and quantify the volatile components. The gas chromatograph allows for the observation of all peaks of volatile components, and by using an analytical method utilizing electromagnetic interactions, it is also possible to quantify volatile substances, monomers, etc. with high accuracy.

[0253] <Peeling Tension> The peeling tension when peeling the support and the web is preferably 300 N / m or less, more preferably in the range of 196 to 245 N / m, but if wrinkles are likely to occur during peeling, peeling is preferably performed at a tension of 190 N / m or less.

[0254] (B) First-stage stretching step (S4) The first-stage stretching step (S4) is a step of stretching the web in the first stage with respect to the web width immediately after casting, and in this step (S4), the web after peeling from the support is stretched in the machine direction (hereinafter also referred to as "MD direction"). In this case, the web shrinks in the width direction (transverse direction, hereinafter also referred to as "TD direction") perpendicular to the MD direction within the web plane.

[0255] Methods for shrinking the web include, for example, (1) subjecting the web to high temperature treatment without holding the width of the web to increase the density of the web, (2) applying tension to the web in the conveying direction (MD direction) to shrink the web in the width direction (TD direction), and (3) rapidly reducing the amount of residual solvent in the web.

[0256] The stretching may be performed according to the required optical properties, and is preferably performed in at least one direction, or may be performed in two mutually perpendicular directions. For example, the film may be biaxially stretched in the width direction (TD direction) of the film and in the conveying direction (MD direction) perpendicular thereto. When performing biaxial stretching, the stretching ratio is preferably set within the range of 1.1 to 2.0 times in each of the TD and MD directions. The stretching ratio is defined as (stretched film size in the stretched direction) / (stretched film size in the stretched direction) of the film before stretching.

[0257] <Residual Solvent Amount> In the present invention, the residual solvent amount immediately before the first-stage stretching is the same as the residual solvent amount at the peeling point in the peeling step (S3) described above. From the viewpoints of improving the adhesiveness of the film and suppressing deterioration of the film strength, it is preferable that the residual solvent amount immediately before the first-stage stretching is in the range of 1 to 15 mass % and the stretching ratio is in the range of 1.1 to 2.0.

[0258] The first-stage stretching step (S4) promotes entanglement between polymer molecules (matrix molecules) in the thickness direction of the web, which makes it easier for the adhesive to penetrate into the substrate film through the entangled portions (crosslinked portions) between the matrix molecules, even when the substrate film is bonded to the carrier film via an adhesive layer during production of the laminated film of the present invention.

[0259] As a result, the substrate film can be firmly fixed to the polarizer layer (also referred to as a "polarizing film," "polarizer film," or "polarizer membrane") via the adhesive, and the peel strength of the substrate film from the polarizer layer can be improved. In other words, the adhesion between the substrate film and the polarizer layer is improved, and the function of suppressing deterioration of the film strength can be ensured.

[0260] (C) Step of Winding Up the Film Formed by Drying the Web The step of winding up the film formed by drying the web includes a drying step (S5), a first cutting step (S6), and a first winding step (S7). １The winding speed in the first winding step (S7) is the same as the transport speed in the first winding step (S7). Strictly speaking, the "same speed" between the transport speed and the winding speed means that they are the same within a range of ±10%.

[0261] (C-1) Drying Step (S5) In the drying step (S5), the web is heated on the support to evaporate the solvent. In the drying device 7 shown in Fig. 5, the web is transported by a plurality of transport rollers arranged in a staggered pattern when viewed from the side, and the web is dried during this transport.

[0262] The drying method in the drying device 7 is not particularly limited, and the web is generally dried using hot air, infrared rays, a heated roller, microwaves, etc., but from the viewpoint of simplicity, a method of drying the web with hot air is preferred. A combination of these methods is also preferred. The drying step (S5) may be performed as needed.

[0263] If the web is thin, it dries quickly, but if it dries too quickly, the flatness of the finished film is likely to be lost.

[0264] When drying at high temperatures, the amount of residual solvent must be taken into consideration, but if the amount of residual solvent is not too high, breakdown due to solvent foaming can be prevented. Drying is generally carried out within a range of approximately 30 to 250°C throughout. Drying within a range of 35 to 200°C is particularly preferred, 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 position.

[0265] In the web drying process, a roller drying method, i.e., a method in which the web is dried by passing it alternately through multiple rollers arranged above and below, or a tenter method in which the web is dried while being transported, is generally used. When a tenter stretching apparatus is used for drying the web, it is preferable to use an apparatus that can independently control the gripping length (the distance from the start of gripping to the end of gripping) of the web on the left and right sides using the left and right gripping means of the tenter stretching apparatus in the stretching process described below. It is also preferable to provide a neutral zone between different temperature compartments to prevent interference between the respective compartments.

[0266] (C-2) First Cutting Step (S6) In the first cutting step (S6), a cutting unit 8 made of a slitter cuts both widthwise ends of the film F that has been stretched in the first-stage stretching step (S4) and has been through the drying step (S5). The portions of the film F that remain after cutting the both ends constitute product portions that will become film products. Meanwhile, the portions cut from the film F may be recovered and reused as part of the raw materials for producing a base film.

[0267] (C-3) First Winding Step (S7) In the first winding step (S7), the film F is wound at a transport speed V １ (Wind-up speed V １ ) and is wound by a winding device 9, completing the process of producing a raw film. The preferable range of the initial tension when winding the film F in the winding process is within the range of 20 to 300 N / m.

[0268] (4.1.2) Processing step of raw film The processing step of raw film is a step of transporting the wound film and performing a second-stage stretching. The processing step of raw film is composed of (D) a step of unwinding the raw film, (E) a step of performing a second-stage stretching, and (F) a step of winding the stretched film. In detail, the processing step includes a step (S8) of unwinding the wound film from the roll body, and a conveying speed V that satisfies the above formula (1). ２ The process includes at least a feeding step (S8), a second-stage drawing step (S9), a second cutting step (S10), and a second winding step (S11).

[0269] In the step of subjecting the wound film to the second-stage stretching, the amount of residual solvent immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass relative to the winding width.

[0270] (D) Raw Film Unwinding Step (S8) In the raw film unwinding step (S8), the wound film is unwound from the roll at a transport speed V ２ Transported by.

[0271] <Residual Solvent Amount> The film is then subjected to a second-stage stretching. At this time, the residual solvent amount immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass.

[0272] (E) Step of second-stage stretching (S9) In the step of second-stage stretching (S9), the conveying speed V ２ The film F transported through the process is stretched by the stretching device 10. The main means for controlling the heat shrinkage rate according to the present invention is the stretching method in the second-stage stretching step (S9).

[0273] One of the features of the present invention is to control the heat shrinkage rate of the laminate portion, and the effects of the present invention are realized mainly by controlling the heat shrinkage rate of the base film in the laminate portion. The main means for controlling the heat shrinkage rate are as described above.

[0274] As a stretching method, a method in which a difference in peripheral speed between rollers is used to stretch in the conveyance direction (longitudinal direction of the film; film-forming direction; casting direction; MD direction), or a tenter method in which both side edges of the film are fixed with clips or the like and stretched in the width direction (direction perpendicular to the film plane; TD direction), is preferred in order to improve the performance, productivity, flatness, and dimensional stability of the film.

[0275] In the case of the so-called tenter method, it is preferable to drive the clip portion using a linear drive system, as this allows smooth stretching and reduces the risk of breakage. The width retention and transverse stretching in the film-forming process are preferably performed using a tenter stretching device, which may be a pin tenter or a clip tenter. In addition to stretching, drying may also be performed in the stretching device 10.

[0276] The second-stage stretching step (S9) may be a step of stretching the film only in the MD direction within the film plane, a step of stretching only in the TD direction, a step of stretching in both the MD and TD directions, or a step of stretching in an oblique direction. There is no limitation on the stretching direction, but from the viewpoint of obtaining a wide film, it is preferable to include a step of stretching at least in the width direction. Such stretching can be performed using a stretching apparatus 10.

[0277] In order to ensure a high retardation, a wide width, and promote adhesive penetration when adhering to a carrier film or a cured layer, it is preferable to stretch the film at a high ratio in the second-stage stretching step. However, if the stretching ratio is too high, crazes may occur in the film due to stretching stress, and the entanglement between matrix molecules that maintain the film strength may be dissociated, weakening the film. For this reason, from the viewpoint of realizing the effects of the present invention, it is more preferable that the stretching ratio in the second-stage stretching step be within the range of 1.1 to 2.0 times. On the other hand, because stretching at a high ratio results in too thin a film and there is a risk of breakage during production, it is more preferable that the stretching ratio be within the range of 1.3 to 1.8 times.

[0278] In addition, when stretching is performed multiple times, such as stretching after the peeling step and stretching in the second-stage stretching step, as in the present invention, it is preferable that the highest stretching magnification, which poses the highest risk of dissociation of matrix molecules, is performed in the final stretch of the multiple stretching steps. Therefore, in the present invention, it is preferable that stretching at the highest magnification is performed in the second-stage stretching step. In this case, the entanglement of matrix molecules can be strengthened before stretching at the highest magnification, so that dissociation of entangled matrix molecules can be suppressed and cohesive failure can be suppressed even when stretching at the highest magnification.

[0279] <Residual Solvent Amount> The residual solvent amount in the film at the time of stretching is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0280] (Tenter Stretching Apparatus) A tenter stretching apparatus is an apparatus that stretches a film by gripping both widthwise ends of the film with clips and expanding the gap between the clips while traveling together with the film. A tenter stretching apparatus is usually divided into multiple zones, and for example, as shown in Figure 6, it is provided with a preheating zone for heating the film, a transverse stretching zone for stretching the film in the transverse direction, a heat setting zone for crystallizing the film, a relaxation zone for removing thermal stress from the film, etc.

[0281] In this embodiment, the tenter stretching device 40 may not only perform transverse stretching but also perform longitudinal stretching simultaneously. In this case, the pitch of the clips 42 (the distance between the clips 42 in the conveyance direction) may be changed when the clips 42 move. A pantograph mechanism or a linear guide mechanism, for example, may be used as a mechanism for changing the pitch of the clips 42.

[0282] Methods for stretching a film include stretching in the machine (lengthwise) direction (machine stretching), stretching in the transverse (width) direction (transverse stretching), sequential stretching in the machine and transverse directions (sequential biaxial stretching), and simultaneous stretching in the machine and transverse directions (simultaneous biaxial stretching). Of these, a tenter stretching apparatus is used for transverse stretching and simultaneous biaxial stretching (including oblique stretching).

[0283] An apparatus used as a tenter stretching apparatus will be described below with reference to FIGS. 6, 7, 8 and 9. FIG.

[0284] Fig. 6 is a plan view schematically showing the internal configuration of a tenter stretching apparatus, and is a cross-sectional view of the tenter stretching apparatus viewed from above along a plane perpendicular to the film surface, with the cover removed, and the cover is indicated by a two-dot chain line.

[0285] The tenter stretching device 40 is equipped with a large number of clips 42 that grip both widthwise ends of the film F, and the clips 42 are attached at regular intervals to an endless chain 48. The endless chains 48 are arranged on both sides of the film F, and each chain is stretched between a driving sprocket 50 on the inlet side and a driven sprocket 52 on the outlet side. The driving sprocket 50 is connected to a motor (not shown), and driving this motor rotates the driving sprocket 50. As a result, the endless chain 48 travels in a circular motion between the driving sprocket 50 and the driven sprocket 52, causing the clips 42 attached to the endless chain 48 to travel in a circular motion.

[0286] Rails 54 for guiding the endless chain 48 (or clips 42) are provided between the driving sprocket 50 and the driven sprocket 52. The rails 54 are arranged on both sides of the film F, and the distance between the rails 54 is configured to be wider on the downstream side than on the upstream side in the transport direction of the film F. As a result, the distance between the clips 42 is widened as the clips 42 travel around, allowing the film F gripped by the clips 42 to be transversely stretched in the width direction.

[0287] A release member 56 is attached to each of the driving sprocket 50 and the driven sprocket 52. The release member 56 is a device that displaces a flapper (not shown) of the clip 42 (described later) from a gripping position to a release position, and the film F is automatically gripped and released by the release member 56.

[0288] As shown in FIG. 6, the tenter stretching apparatus 40 is provided with a preheating zone, a (transverse) stretching zone, and a heat setting zone. The zones are separated by windshield curtains (not shown). In each zone, hot air is supplied to the film F from above, below, or both. The hot air is blown uniformly across the width of the film F, controlled to a predetermined temperature for each zone. This allows the interior of each zone to be controlled to the desired temperature. Each zone will be described below.

[0289] The preheating zone is a zone in which the film F is preheated, and the film F is heated without widening the gap between the clips 42. The film F preheated in the preheating zone moves to the transverse stretching zone.

[0290] The transverse stretching zone is a zone in which the film F is stretched transversely in the width direction by widening the gap between the clips 42. The stretching ratio in this transverse stretching process is preferably within the range of 1.0 to 2.5 times, more preferably within the range of 1.05 to 2.3 times, and even more preferably within the range of 1.1 to 2 times. The film F that has been transversely stretched in the transverse stretching zone is moved to the heat setting zone.

[0291] In this embodiment, the interior of the tenter 40 is divided into a preheating zone, a (transverse) stretching zone, and a heat setting zone, but the types and arrangement of the zones are not limited to these. For example, a cooling zone for cooling the film F may be provided after the transverse stretching zone. Also, a heat relaxation zone may be provided within the heat setting zone.

[0292] [Oven Temperature] Generally, the oven temperature is preferably in the range of 120 to 300°C, more preferably in the range of 180 to 250°C. Here, the "oven temperature" in the present invention refers to the temperature measured in the stretching zone of a tenter stretching apparatus at a position 100 mm above the center of the film immediately before stretching (see Figure 7). Each temperature value is measured every minute for one hour, and the average value is calculated. Generally, the oven temperature is preferably in the range of 120 to 300°C, more preferably in the range of 180 to 250°C. Here, when a temperature gradient is created longitudinally in multiple sections, the heat treatment section is the target. Furthermore, in the present invention, the oven temperature differs depending on whether or not heat treatment is performed in the stretching zone. However, when heat treatment is performed in the stretching zone, the oven temperature refers to the oven temperature in the stretching zone before heat treatment.

[0293] FIG. 8 is a plan view of the three zones in the tenter stretching apparatus, and FIG. 9 is a schematic view of the nozzles and heaters installed in the three zones in the tenter stretching apparatus as viewed from the front.

[0294] There are no particular restrictions on the heating method within the tenter, but as with the first drying step (S5), hot air, infrared rays, heated rollers, microwaves, etc. can generally be used. When an infrared (IR) heater is used, it is placed only above the nozzle so that the film does not come into contact with the infrared (IR) heater when the film breaks, as shown in Figure 9. Furthermore, since the radiant energy from the infrared (IR) heater can be concentrated in a narrower area by placing the infrared (IR) heater closer to the film, the infrared (IR) heater is placed as close to the film as possible within a range that does not interfere with the tentering operation using the clips.

[0295] FIG. 9 shows the heat treatment mainly from the central nozzle, and in this example, the heat treatment from the end nozzles is not performed, but in this embodiment, both can be used.

[0296] In the stretching device, infrared (IR) heaters projecting from the nozzle gaps as shown in Figure 7 allow for efficient transfer of radiant energy to the film. As shown in Figure 8, infrared (IR) heaters were arranged in rows so that the entire width of the film could be heated even before stretching. The heaters may also be arranged in a staggered pattern in the longitudinal direction.

[0297] (Others) In the second-stage stretching step (S9), the film F may be dried, if necessary, in the same manner as in the first drying step (S5). The drying method is not particularly limited, and generally, hot air, infrared rays, a heated roller, microwaves, etc. can be used. Among these drying methods, a method of drying the film F with hot air is preferred from the viewpoint of simplicity.

[0298] (F) Step of Winding the Stretched Film The step of winding the stretched film comprises a second cutting step and a second winding step.

[0299] (F-1) Second Cutting Step (S10) In the second cutting step (S10), a cutting unit 11 consisting of a slitter cuts both widthwise ends of the film F stretched in the second-stage stretching step (S9). The portions of the film F remaining after cutting the both ends constitute product portions that will become film products. Meanwhile, the portions cut from the film F may be recovered and reused as part of the raw material for film production.

[0300] (F-2) Second Winding Step (S11) In the second winding step (S11), the film F is wound at a transport speed V ２The film F is then wound by the winding device 12 at a predetermined speed. At this time, it is preferable to apply a protective film while winding. In this case, 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 of the initial tension when winding the film F in the second winding step (S11) is in the range of 20 to 300 N / m.

[0301] The film F can be wound using a commonly used winder, and various tension control methods such as the constant torque method, constant tension method, taper tension method, and program tension control method with constant internal stress can be used appropriately.

[0302] Before winding, the ends are slit and cut to the width of the product, and both ends of the film may be subjected to a surface modification treatment to prevent sticking or scratches during winding.

[0303] <Residual Solvent Amount> The residual solvent amount in the film in the second winding step is 2% by mass or less. In this case, a residual solvent amount of 0.4% by mass or less is preferred from the viewpoint of obtaining a film with good dimensional stability, and the residual solvent amount is more preferably in the range of 0.00 to 0.20% by mass.

[0304] (4.2) Melt Casting Film Forming Method The "melt casting film forming method" refers to 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 melt containing the fluid thermoplastic resin is cast. Molding methods involving heating and melting can be specifically classified into melt extrusion molding, press molding, inflation molding, injection molding, blow molding, stretch molding, etc. Among these molding methods, melt extrusion is preferred from the standpoints of mechanical strength, surface precision, etc.

[0305] In the process for producing a substrate film by the melt-casting film-forming method according to the present invention, the process for producing a raw film comprises at least the following three steps (A), (B), and (C).

[0306] (A) A process of casting molten resin / pellets onto a support to form a web; (B) A process of performing the first stage of stretching; and (C) A process of drying the web and winding up the formed film.

[0307] The raw film processing step is a step of transporting the wound raw film and performing a second stage of stretching.

[0308] In the step of subjecting the wound film to the second-stage stretching, the amount of residual solvent immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass relative to the winding width.

[0309] Fig. 10 is a flowchart showing the flow of the process for producing a substrate film by melt-casting. Fig. 11 is a schematic diagram of an apparatus for producing a substrate film by melt-casting. The melt-casting method will be described below with reference to Figs. 10 and 11.

[0310] As shown in FIG. 10 , the process for producing a substrate film by the melt-casting method includes an extrusion step (M1), a casting / molding step (M2), a first-stage stretching step (M3), a drying step (M4), a first cutting step (M5), a first winding step (M6), a payout step (M7), a second-stage stretching step (M8), a second cutting step (M9), and a second winding step (M10).

[0311] (4.2.1) Preparation of Raw Film The process for preparing raw film by the melt casting method comprises at least the steps of (G) casting molten resin / pellets onto a support to form a web, (H) performing the first stage of stretching, and (I) drying the web and winding up the film formed.

[0312] (G) Step of Casting Molten Resin / Pellets onto a Support to Form a Web The step of casting molten resin / pellets onto a support to form a web comprises at least an extrusion step (M1) and a casting / molding step (M2).

[0313] (G-1) Extrusion Step (M1) In the extrusion step (M1), at least a resin is melt-extruded in an extruder 14 and molded onto a cast drum 16. Details of the resin that can be used in the present invention will be described later. The resin is preferably kneaded and pelletized in advance, and pelletization can be performed by a known method. Known methods include, for example, feeding a dry resin, a plasticizer, and other additives to an extruder using a feeder, kneading them using a single-screw or twin-screw extruder, extruding them into strands from a casting die, cooling them with water or air, and cutting them to form pellets.

[0314] The additives may be mixed with the resin before being fed to the extruder, or the additives and resin may be fed to the extruder using separate feeders. It is also preferable to mix small amounts of additives, such as particles and antioxidants, with the resin in advance to ensure uniform mixing.

[0315] When introducing pellets from the supply hopper into the extruder, it is preferable to prevent oxidative decomposition by drying, vacuum, reduced pressure, or an inert gas atmosphere. It is preferable that the extruder be capable of pelletizing and process at as low a temperature as possible to reduce shear force and prevent resin deterioration (molecular weight reduction, coloration, gel formation, etc.). For example, in the case of a twin-screw extruder, it is preferable to use deep-groove type screws that rotate in the same direction. For uniform mixing, an intermeshing type is preferable. When melted, the resin / pellets are preferably filtered through a leaf disc type filter or the like to remove foreign matter.

[0316] The pellets obtained as described above are used to form a web. Of course, it is also possible to directly feed the raw resin (powder, etc.) into an extruder using a feeder and form a web without pelletizing it.

[0317] (G-2) Casting and Molding Step (M2) In the casting and molding step (M2), the resin or pellets molten in the extrusion step are passed through a pressure-type metering gear pump or the like and cast into a film form from a casting die 15 through a conduit. Then, the molten resin or pellets are cast from the casting die 15 onto a casting position on an endless, rotationally driven, stainless steel casting drum 16. The cast molten resin or pellets are then molded on the casting drum 16 to form a web.

[0318] The inclination of the casting die 15, i.e., the direction of the molten resin / pellets being discharged from the casting die 15 to the support 16, may be set appropriately so that the angle with respect to the normal to the surface of the cast drum 16 (the surface onto which the molten resin / pellets are cast) falls within the range of 0 to 90°.

[0319] The film F may be formed by using a touch roller 16a or a cooling drum 17 that assists the casting drum 16, either alone or in combination as appropriate (hereinafter, the "web" after cooling will also be referred to as "film F").

[0320] (H) First-stage stretching step (M3) In the first-stage stretching step (M3), the film F is stretched by the stretching device 18. The stretching method and the like at this time are the same as those in the first-stage stretching step (S4) when producing a base film by the solution casting method.

[0321] (I) Step of drying the web and winding up the film The step of drying the web and winding up the film comprises a drying step (M4), a first cutting step (M5), and a first winding step (M6). １ The winding speed in the first winding step (M6) is the same as the transport speed in the second winding step (M7). Strictly speaking, the "same speed" between the transport speed and the winding speed means that they are the same within a range of ±10%.

[0322] The drying step (M4), the first cutting step (M5), and the first winding step (M6) are the same as the drying step (S5), the first cutting step (S6), and the first winding step (S7) when producing a base film by the solution casting method.

[0323] (4.2.2) Processing step of raw film When producing a base film by melt casting, the processing step of raw film is a step of conveying the wound film and performing a second-stage stretching. The processing step of the raw film is composed of (J) a step of unwinding the raw film, (K) a step of performing a second-stage stretching, and (L) a step of winding the stretched film. In detail, the processing step includes a step (M7) of unwinding the wound film from the roll body, and a step (L) of winding the stretched film at a conveying speed V ２ The process comprises at least a feeding step (M7), a second-stage drawing step (M8), a second cutting step (M9), and a second winding step (M10).

[0324] In the step of subjecting the wound film to the second-stage stretching, the amount of residual solvent immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass relative to the winding width.

[0325] (J) Unwinding Step (M7) In the unwinding step (M7), the wound film is unwound from the roll at a conveying speed V ２ Transported by.

[0326] <Residual Solvent Amount> The film is then subjected to a second-stage stretching. At this time, the residual solvent amount immediately before the second-stage stretching is in the range of 0.1 to 0.5% by mass.

[0327] (K) Second-stage stretching step (M8) In the second-stage stretching step (M8), the conveying speed V ２ The film F being transported is stretched by the stretching device 21. The stretching method at this time is the same as the second-stage stretching step (S9) when producing a base film by the above-mentioned solution casting method.

[0328] <Residual Solvent Amount> The residual solvent amount in the film at the time of stretching is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0329] (Tenter Stretching Apparatus) The tenter stretching apparatus may be the same as that used in the solution casting film-forming method.

[0330] (Others) In the second-stage stretching step (M8), the film F may be dried, if necessary, in the same manner as in the drying step (M4). The drying method is not particularly limited, and generally, hot air, infrared rays, a heated roller, microwaves, etc. can be used. Among these drying methods, the method of drying the film F with hot air is preferred from the viewpoint of simplicity.

[0331] (L) Step of Winding Up the Stretched Film The step of winding up the stretched film comprises a second cutting step (M9) and a second winding step (M10).

[0332] (L-1) Second Cutting Step (M9) In the second cutting step (M9), a cutting section 22 consisting of a slitter cuts both widthwise ends of the film F stretched in the second-stage stretching step (M8). The portions of the film F remaining after cutting the both ends constitute product portions that will become the film product. Meanwhile, the portions cut from the film F may be recovered and reused as part of the raw material for film production.

[0333] (L-2) Second Winding Step (M10) In the second winding step (M10), the film F is wound at a transport speed V ２ The film F is then wound up by the winding device 23 at a predetermined speed. At this time, it is preferable to apply a protective film while winding. In this case, 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 of the initial tension when winding the film F in the second winding step (M10) is in the range of 20 to 300 N / m.

[0334] The film F can be wound using a commonly used winder, and various tension control methods such as the constant torque method, constant tension method, taper tension method, and program tension control method with constant internal stress can be used appropriately.

[0335] Before winding, the ends are slit and cut to the width of the product, and both ends of the film may be subjected to a surface modification treatment to prevent sticking or scratches during winding.

[0336] <Residual Solvent Amount> The residual solvent amount in the film in the second winding step is 2% by mass or less. In this case, a residual solvent amount of 0.4% by mass or less is preferred from the viewpoint of obtaining a film with good dimensional stability, and the residual solvent amount is more preferably in the range of 0.00 to 0.20% by mass.

[0337] 5. Step of Forming Second Adhesive Layer (S12) In the step of forming the second adhesive layer (S12), the wound substrate film is unwound, and the aforementioned composition for the second adhesive layer is applied (coated) to the surface of the substrate film. At this time, if a protective film is attached, the protective film is peeled off. Thereafter, the substrate film is dried or heated to form a second adhesive layer on one side thereof, and a protective film is attached to the second adhesive layer, followed by winding. At this time, it is preferable to attach a protective film to the side opposite to the second adhesive layer. Hereinafter, the substrate film with the protective film produced in the step of forming the second adhesive layer (S12) is referred to as substrate film F. Ｓ１２ In addition, the "Base film F" Ｓ１２ The "S12" in "" means that the film was produced by the step of forming the second adhesive layer (S12). The winding method is not particularly limited, and can be carried out by a conventionally known method.

[0338] 6. First Adhesive Layer Forming Step (S13) In the first adhesive layer forming step (S13), the wound substrate film F Ｓ１２ The base film F Ｓ１２ After peeling off the protective film attached to the first adhesive layer, the composition for the first adhesive layer is applied (coated) to the other surface of the base film on which the second adhesive layer is not formed. Thereafter, the first adhesive layer is formed on the other surface of the base film by drying or heating, and a carrier film is attached to the first adhesive layer, followed by winding up. Hereinafter, the base film with the carrier film produced in the first adhesive layer forming step (S13) is referred to as base film F. Ｓ１３ In addition, the "Base film F"Ｓ１３ The "S13" in "1" means that the film was produced by the first adhesive layer forming step (S13). The winding method is not particularly limited, and can be carried out by a conventionally known method.

[0339] 7. Step of forming multiple cured layers Although the multiple cured layers according to the present invention may be three or more layers, here, a case where only two layers are formed will be described as an example of multiple cured layers. A first adhesive layer is formed on one side of the above-mentioned base film, and a second adhesive layer is formed on the other side, and the film is then wound up. In other words, the laminate portion according to the present invention is formed and wound up.

[0340] (7.1) First Hardened Layer Forming Step (S14) In the first hardened layer forming step (S14), the wound substrate film F Ｓ１３ The base film F Ｓ１３ A coating liquid of a curable layer composition according to the purpose is applied to the surface of the substrate on the side of the second adhesive layer formed on the substrate. Hereinafter, the coating liquid of the curable layer composition applied when forming the first cured layer will be referred to as "coating liquid [1] of the curable layer composition." Hereinafter, if it is desired to form a low refractive index layer on the second adhesive layer, it is preferable to prepare the above-mentioned coating liquid [1] of the curable layer composition as a coating liquid of the low refractive index layer composition. Thereafter, the coating liquid [1] of the curable layer composition is cured and dried, and then wound up.

[0341] In this case, in the present invention, since the cured layer formed on the second adhesive layer is a low refractive index layer, the coating liquid of the composition for the low refractive index layer may contain, for example, an ultraviolet-curable resin composition and beads (organic resin particles) with a diameter of approximately 8 μm.

[0342] There are no particular limitations on the curing and drying of the coating liquid [1] of the curable layer composition, but for example, curing may be performed using ultraviolet light, followed by application of hot air, etc. After curing and drying, the coating liquid [1] of the curable layer composition becomes a coating film, which will hereinafter be referred to as the "cured layer [1]."

[0343] In the present invention, when the cured layer [1] is formed by curing and drying a coating liquid of a composition for a low refractive index layer, for example, the beads (organic resin particles) having a diameter of about 8 μm may protrude by about ⅓ of their diameter.

[0344] The carrier film on the first adhesive layer side, on which the cured layer [1] is not formed, remains attached. Hereinafter, the base film after the formation of the cured layer produced in the first cured layer forming step (S14) is referred to as base film F. Ｓ１４ In addition, the "Base film F" Ｓ１４ "S14" in "" means that it was produced by the first hardened layer forming step (S14).

[0345] (7.2) Second Hardened Layer Forming Step (S15) In the second hardened layer forming step (S15), the wound substrate film F Ｓ１４ The base film F Ｓ１４ A coating liquid [2] of the curable layer composition is applied to the surface of the curable layer [1] side of the curable layer. Here, when it is desired to form a high refractive index layer on the first cured layer, that is, when it is desired to make the second cured layer a high refractive index layer, it is preferable to prepare the above-mentioned coating liquid [2] of the curable layer composition as a coating liquid of the high refractive index layer composition. Thereafter, the coating liquid [2] of the curable layer composition is cured and dried, and then wound up.

[0346] In this case, when the second cured layer is to be a high refractive index layer, the coating liquid [2] of the composition for the cured layer contains, for example, an ultraviolet curable resin composition and zirconium oxide (ZrO ２ , refractive index: 2.10) fine particles may be contained.

[0347] There are no particular limitations on the curing and drying of the coating liquid [2] of the curable layer composition, but for example, curing may be performed using ultraviolet light, followed by application of hot air, etc. After curing and drying, the coating liquid [2] of the curable layer composition becomes a coating film, which will hereinafter be referred to as the "cured layer [2]."

[0348] In the present invention, the cured layer [2] may be formed by curing and drying a coating liquid of a composition for a low refractive index layer, or by curing and drying a coating liquid of a composition for a high refractive index layer. When the cured layer [2] is formed by curing and drying a coating liquid of a composition for a high refractive index layer, the beads (organic resin particles) do not protrude from the outermost layer, and may be completely embedded in the cured layer.

[0349] The carrier film on the first adhesive layer side, on which the cured layer [2] is not formed, remains attached. Hereinafter, the substrate film after the formation of the cured layer produced in the second cured layer forming step (S15) is referred to as substrate film F. Ｓ１５ In addition, the "Base film F" Ｓ１５ "S15" in "" means that it was produced by the second hardened layer forming step (S15).

[0350] From the above, the laminated film of the present invention is Ｓ１５ is synonymous with.

[0351] [III. Display Device] The display device of the present invention is a display device equipped with an optical film, and is characterized in that the portion of the laminate film of the present invention excluding the carrier film is equipped as the optical film.

[0352] For example, Fig. 12 shows a specific example in which the laminated film of the present invention, excluding the carrier film, can be applied to a self-emitting light source. Examples of application include those shown in Fig. 12A and Fig. 12B. It is assumed that the laminated film shown in Fig. 1A is applied.

[0353] The self-emitting light source may be a surface-emitting OLED or other suitable self-luminous light source that is fabricated separately from the laminate film to create an enhanced light-emitting optical device or other display device, although the surface-emitting OLED is shown schematically for ease of illustration.

[0354] To provide enhanced optical performance for the OLED, the laminate film of the present invention is applied to the light-emitting surface Sb of the OLED. Prior to application, the carrier film CF is removed from the laminate film F1, exposing the surface Sa. In some cases, the optical coupling surface of the laminate film of the present invention may be placed directly against the light-emitting surface Sb of the OLED. Direct contact between the surface Sa (optical coupling surface) of the laminate film of the present invention excluding the carrier film and the light-emitting surface Sb of the OLED may be sufficient to create a film bond between the two components without a significant air gap between them.

[0355] Thus, the combination of the laminate film of the present invention, excluding the carrier film, with an OLED can be implemented with a wide variety of known OLEDs, including non-pixelated OLEDs that may typically be used in lighting applications, but is particularly practical when used with pixelated OLEDs that may typically be used to generate images in electronic displays.

[0356] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, the terms "parts" and "%" are used, but unless otherwise specified, they represent "parts by mass" or "% by mass."

[0357] [Preparation of Laminated Film [1]] [1] Preparation of Protective Film and Carrier Film In preparing the laminated film [1], first, the following protective film [1] and carrier film [A] were prepared as protective films.

[0358] Protective film [1]: Polyester film "Tretec 7832C" (thickness 30 μm, manufactured by Toray Advanced Film Co., Ltd.) Carrier film [A]: Polyethylene terephthalate film "SAT-EBF01" (manufactured by San-A Kaken Co., Ltd., thickness 38 μm, acrylic adhesive layer: 10 μm)

[0359] [2] Preparation of Substrate Film The substrate film was prepared by a solution casting method.

[0360] [2-1] Dope Preparation Step (S1) 100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester were charged into a stirrer. Next, 25 mmol% (relative to the monomer mass) of ethylhexanoate-Ni dissolved in toluene, 0.225 mol% (relative to the monomer mass) of tri(pentafluorophenyl)boron, and 0.25 mol% (relative to the monomer mass) of triethylaluminum dissolved in toluene were charged into the stirrer. The mixture was then reacted for 18 hours with stirring at room temperature. After completion of the reaction, the reaction mixture was charged into excess ethanol to produce a polymer precipitate. The precipitate was purified, and the resulting cyclic polyolefin polymer (P-1) was dried in a vacuum at 65°C for 24 hours.

[0361] Next, the following composition [1] containing the cyclic polyolefin polymer (P-1) prepared by the above method was charged into a mixing tank, stirred to dissolve each component, and then filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm to prepare a dope (D-1).

[0362] <Composition [1]> Cyclic polyolefin polymer (P-1) 150 parts by mass Dichloromethane 380 parts by mass Ethanol 70 parts by mass

[0363] Next, the following composition [2] containing the dope (D-1) prepared by the above method was charged into a disperser to prepare a fine particle dispersion (M-1) as an additive.

[0364] <Composition [2]> Fine particles "Aerosil R812" (manufactured by Nippon Aerosil Co., Ltd., average primary particle size: 7 nm, apparent specific gravity 50 g / L) 4 parts by mass Dichloromethane 76 parts by mass Ethanol 10 parts by mass Dope (D-1) 10 parts by mass

[0365] 100 parts by mass of the above cyclic polyolefin solution (dope (D-1)) and 0.75 parts by mass of the fine particle dispersion (M-1) were mixed to prepare a film-forming dope (COP1) containing a cycloolefin resin as a resin composition.

[0366] [2-2] Casting Step (S2) The dope (COP1) was sent to a casting die through a conduit via a pressure-type metering gear pump. The dope (COP1) was then cast from the casting die onto a casting position on a support made of a rotating stainless steel endless belt, which was transported endlessly, in a width of 1,300 mm on a film-forming line. 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 from the support with a peel roller, forming a web. The dope (COP1) was conveyed at a speed V １ The spin speed was 55 m / min.

[0367] [2-3] Peeling Step (S3) After the web was formed in the casting step (S2), the web was peeled from the support by a peeling roller while maintaining its self-supporting property.

[0368] [2-4] Step (S4) of performing first-stage stretching: The web was treated at a high temperature without holding the width to increase the density of the web, and the first-stage stretching was performed while shrinking the web width in the width direction relative to the web width immediately after casting. The amount of residual solvent measured immediately before the first-stage stretching was 12% by mass. The stretching ratio was 1.50.

[0369] [2-5] Drying Step (S5) Thereafter, the web was heated on the support to evaporate the solvent from the web.

[0370] [2-6] First Cutting Step (S6) Both ends in the width direction of the web from which the solvent had evaporated were cut to prepare a raw film.

[0371] [2-7] First Winding Step (S7) The raw film is wound at a transport speed V １ (V １ The film was wound onto a core by a winding device while being transported at a speed of 55 m / min. The initial tension was 50 N, the taper was 70%, and the corners were 25%.

[0372] [2-8] Raw Film Unwinding Process (S8) The wound raw film is fed at a transport speed V ２ The yarn was unwound at a speed of 10 m / min.

[0373] [2-9] Second-stage stretching step (S9) The unwound raw film is conveyed through the stretching device at a conveying speed V ２ The film was then conveyed at a speed of 10 m / min, and the second-stage stretching was performed. The residual solvent content immediately before the second-stage stretching was measured and found to be 0.30% by mass. The stretching ratio was 1.40.

[0374] [2-10] Second cutting step (S10) As in the first cutting step, both ends of the stretched raw film in the width direction were cut and processed to produce a base film. Hereinafter, this base film will be referred to as "base film [A]".

[0375] [2-11] Second Winding Step (S11) The above-mentioned base film [A] was wound up while the above-mentioned protective film [1] was attached to the base film [A]. The initial tension was 50 N, the taper was 70%, and the corners were 25%.

[0376] By the above steps, a substrate film [A] was produced. The thickness of the substrate film [A] produced by the above steps was 15 μm.

[0377] [3] Step of forming second adhesive layer (S12) [3-1] Preparation of composition for second adhesive layer The following components were diluted with a diluent (water: 2588 parts by mass / methanol: 1464 parts by mass) to prepare a composition for second adhesive layer [1]. Note that the silica microparticle dispersion [1] in the following components is a methanol dispersion of "Seahoster KE-30" manufactured by Nippon Shokubai Co., Ltd., in which silica microparticles with an average particle diameter of 300 nm are dispersed, and the solid content is 5%.

[0378] <Ingredients> "Arrowbase SE-1030E" (acid-modified polyolefin resin) 680 parts by weight "Epocross WS-700" (oxazoline-based acrylic resin) 30 parts by weight Silica microparticle dispersion liquid [1] (contents are as described above)

[0379] In the above components, "Arrowbase SE-1030E" (polyolefin resin) is manufactured by Unitika Ltd. and has a solid content of 22.0%. "Epocross WS-700" (oxazoline-based acrylic resin) is manufactured by Nippon Shokubai Co., Ltd. and has a solid content of 25%.

[0380] [3-2] Application, drying, and curing of the composition for the second adhesive layer The protective film [1] was peeled off from the base film [A] with the protective film [1] wound up in the second winding step (S11), and the base film [A] was unwound at a conveying speed of 20 m / min. At this time, the composition for the second adhesive layer [1] was applied to the base film [A] using a vacuum extrusion die coater, and dried and cured in an atmosphere of 120°C to form a second adhesive layer with a thickness of 320 nm. Furthermore, while conveying at the same conveying speed of 20 m / min as above, the protective film [1] was attached to the second adhesive layer and wound up. Hereinafter, an adhesive layer formed by the same steps as this second adhesive layer, in which the resin type, type of inorganic particles, average particle size, and thickness contained in the adhesive layer are all the same, will be referred to as "adhesive layer [A]."

[0381] [4] Step of forming first adhesive layer (S13) [4-1] Preparation of composition for first adhesive layer A composition for the first adhesive layer was prepared in the same manner as in the preparation of the composition for the second adhesive layer. Hereinafter, this composition for the first adhesive layer will be referred to as "composition for the first adhesive layer [1]".

[0382] [4-2] Application, drying, and curing of the composition for the first adhesive layer The protective film [1] was peeled off from the base film [A] with the protective film [1] that had been taken up in the second adhesive layer formation step (S12), and the film was then unwound at a conveying speed of 20 m / min. At this time, the composition for the first adhesive layer [1] was applied to the other surface of the base film [A] on which the second adhesive layer was not formed, using a vacuum extrusion die coater, and dried and cured in an atmosphere at 120 ° C. to form a first adhesive layer with a thickness of 320 nm. In addition, a carrier film [A] was attached to the first adhesive layer while being conveyed at the same conveying speed of 20 m / min as above, and the film was then wound up.

[0383] The first adhesive layer is formed by the same process as the second adhesive layer described above, and the resin type, inorganic particle type, average particle size, and thickness of the adhesive layer are all the same, so it is adhesive layer [A].

[0384] [5] Step of forming multiple cured layers In the production of the laminated film [1], two cured layers were formed as multiple cured layers.

[0385] [5-1] Step of forming first cured layer (S14) [5-1-1] Preparation of coating liquid of cured layer composition A coating liquid of a cured layer composition was prepared by mixing and stirring the following components. This coating liquid of a cured layer composition is designated as "coating liquid [1] of a cured layer composition." The content of beads in the following components was adjusted so that the content of beads in the following components was 70 parts by mass when the total mass of the coating liquid [1] of a cured layer composition described below was taken as 100 parts by mass.

[0386] <Ingredients: Formulation A1> "KAYARAD PET-30" (binder resin) 30 parts by weight "Irgacure 184" (polymerization initiator) 1.5 parts by weight "Seikabeam 10-28" (silicone leveling agent) 0.05 parts by weight Methyl isobutyl ketone (solvent) 70 parts by weight Beads: "GM-0806S" (contents listed above)

[0387] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0388] The beads "GM-0806S" in the above components are polyacrylic ester manufactured by Aica Kogyo Co., Ltd., and have a refractive index of 1.49 and a number-average particle size of 8 μm.

[0389] [5-1-2] Application of curable layer composition, and curing and drying The base film [A] with the carrier film [A] wound up in the first adhesive layer forming step (S13) was unwound at a conveying speed of 20 m / min. The coating liquid [1] of the curable layer composition was applied to the surface on the second adhesive layer side, dried and UV-cured, and then wound up.

[0390] [5-2] Step of forming second cured layer (S15) [5-2-1] Preparation of coating liquid of cured layer composition The following components were mixed and stirred to prepare a coating liquid of a cured layer composition. This coating liquid of the cured layer composition is referred to as "coating liquid [2] of cured layer composition".

[0391] <Components: Formulation A3> "KAYARAD PET-30" (binder resin) 19.4 parts by mass "Irgacure 184" (polymerization initiator) 0.6 parts by mass "Seikabeam 10-28" (silicone leveling agent) 0.03 parts by mass Methyl isobutyl ketone (solvent) 1129.6 parts by mass Fine particle dispersion "MZ-230X" 51.0 parts by mass

[0392] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0393] The fine particle dispersion "MZ-230X" in the above components is a high refractive index ZrO ２ It is a methyl ethyl ketone dispersion of fine particles, with a solid content of 32.5% by mass.

[0394] [5-2-2] Application of curable layer composition, and curing and drying The substrate film [A] with the carrier film [A] wound up in the first curable layer forming step (S14) and the first cured layer formed thereon was unwound at a conveying speed of 20 m / min. A coating liquid [2] of the curable layer composition was applied to the surface of the first curable layer side, dried, UV-cured, and wound up. A laminated film [1] was produced by the above steps.

[0395] [Preparation of Laminate Film [2]] [1], [2] Preparation of Protective Film, Carrier Film, and Base Film As the protective film and carrier film, a protective film [1] and a carrier film [A] similar to those of the laminate film [1] were prepared. In addition, a base film was not prepared, and instead a commercially available polyester film "Lumirror #16" (resin type: polyethylene terephthalate, thickness 16 μm) manufactured by Toray Industries, Inc. was prepared. Hereinafter, this base film will be referred to as "base film [B]".

[0396] [3] to [5] Steps for forming the second and first adhesive layers to steps for forming multiple cured layers For the second adhesive layer, an adhesive layer [A] was formed in the same manner as for the laminated film [1], and a protective film [1] was attached and wound up. For the first adhesive layer, an adhesive layer [A] was formed in the same manner as for the laminated film [1], and a carrier film [A] was attached and wound up.

[0397] The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in laminate film [1], applying the coating solution, drying, and UV curing, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in laminate film [1], applying the coating solution, drying, and UV curing, and then winding up.

[0398] [Preparation of Laminated Film [3]] [1] Preparation of Protective Film and Carrier Film As the protective film and carrier film, a protective film [1] and a carrier film [A] similar to those of the laminated film [1] were prepared.

[0399] [2] Preparation of the base film The dope preparation step (S1) to the unwinding step (S8) of the raw film were carried out in the same manner as in the laminated film [1]. In the second-stage stretching step (S9), the unwinding raw film was conveyed in the stretching device at a conveying speed V ２ The film was then conveyed at a speed of 8 m / min, and the second-stage stretching was performed. The residual solvent content immediately before the second-stage stretching was measured and found to be 0.30% by mass. The stretching ratio was 1.1.

[0400] In the second cutting and second winding steps (S10 and S11), similar to the first cutting step, both ends of the stretched raw film in the width direction were cut and processed to produce a base film. Hereinafter, this base film will be referred to as "base film [C]." In addition, this base film [C] was wound up while the aforementioned protective film [1] was attached to it. The initial tension was 50 N, the taper was 70%, and the corners were 25%.

[0401] By the above steps, a substrate film [C] was produced. The thickness of the substrate film [C] produced by the above steps was 20 μm.

[0402] [3] to [5] Steps for forming the second and first adhesive layers to steps for forming multiple cured layers For the second adhesive layer, an adhesive layer [A] was formed in the same manner as for the laminated film [1], and a protective film [1] was attached and wound up. For the first adhesive layer, an adhesive layer [A] was formed in the same manner as for the laminated film [1], and a carrier film [A] was attached and wound up.

[0403] The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in laminate film [1], applying the coating solution, curing and drying, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in laminate film [1], applying the coating solution, curing and drying, and then winding up.

[0404] [Preparation of Laminate Film [4]] [1], [2] Preparation of Protective Film and Carrier Film, and Preparation of Base Film The protective film and carrier film were prepared as the same protective film [1] and carrier film [A] as those used in the laminate film [1]. Furthermore, the same substrate film [A] used in the preparation of the laminate film [1] was prepared, except that the heat shrinkage of the laminate portion was appropriately adjusted to the values ​​shown in Table V in the second-stage stretching process. The heat shrinkage was adjusted by appropriately adjusting the stretching temperature, stretching speed, stretch ratio, heating and holding time, cooling speed, residual solvent amount, and relaxation speed after stretching, as described above. Hereinafter, this method will be considered as the method for appropriately adjusting the heat shrinkage of the laminate portion.

[0405] [3] to [5] Steps for forming second and first adhesive layers to step for forming multiple cured layers The second adhesive layer was formed in the same manner as for the laminated film [1], except that "Seahoster KE-30" (silica fine particles) was not included in the components of the composition for the second adhesive layer, and a protective film [1] was attached and wound up. Hereinafter, this adhesive layer will be referred to as "adhesive layer [B]". Similarly, the first adhesive layer was formed in the same manner as for the laminated film [1], except that "Seahoster KE-30" (silica fine particles) was not included in the components of the composition for the first adhesive layer, and a carrier film [A] was attached and wound up.

[0406] The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in laminate film [1], applying the coating solution, curing and drying, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in laminate film [1], applying the coating solution, curing and drying, and then winding up.

[0407] [Preparation of Laminate Film [5]] [1], [2] Preparation of Protective Film and Carrier Film, and Preparation of Base Film As the protective film and carrier film, a protective film [1] and a carrier film [A] similar to those used in the laminate film [1] were prepared. In addition, a film similar to the base film [A] used in the preparation of the laminate film [1] was prepared, except that the thermal shrinkage of the laminate portion was appropriately adjusted in the second-stage stretching step to the values ​​shown in Table V.

[0408] [3] Step of forming second adhesive layer In preparing the composition for the second adhesive layer, the following components were diluted with 912 parts by mass of a diluent (water / methanol = 50 / 50 (mass %)) to prepare a composition [2] for the second adhesive layer. Note that for the silica microparticle dispersion [2] among the following components, "Seahoster KE-30" manufactured by Nippon Shokubai Co., Ltd., in which silica microparticles with an average particle size of 300 nm are dispersed, was blended so that the solid content was 8% relative to the other components.

[0409] <Components> "Acrydic 52-666" (acrylic resin) 124.0 parts by mass "Takenate D110N" (isocyanate-based curing agent) 63.3 parts by mass Silica microparticle dispersion liquid [2] (contents are as described above)

[0410] In the above components, "Acrydic 52-666" (acrylic resin) is manufactured by DIC Corporation and has a solid content of 50%. "Takenate D110N" (isocyanate curing agent) is manufactured by Mitsui Chemicals, Inc. and has a solid content of 60%.

[0411] The protective film [1] was peeled off from the base film [A] with the protective film [1] wound up in the second winding step (S11), and the base film [A] was unwound at a conveying speed of 20 m / min. At this time, a second adhesive layer composition [2] was applied to the base film [A] using a vacuum extrusion die coater, and dried and cured in an atmosphere of 120°C to form a second adhesive layer with a thickness of 320 nm. Furthermore, while conveying at the same conveying speed of 20 m / min as above, the protective film [1] was attached to the second adhesive layer and wound up. Hereinafter, an adhesive layer formed by the same steps as this second adhesive layer, and having the same resin type, inorganic particle type, average particle size, and adhesive layer thickness, will be referred to as "adhesive layer [C]."

[0412] [4] Step of forming first adhesive layer A composition for the first adhesive layer was prepared in the same manner as in the preparation of the composition for the second adhesive layer. Hereinafter, this composition for the first adhesive layer will be referred to as "composition for the first adhesive layer [2]."

[0413] The protective film [1] was peeled off from the base film [A] with the protective film [1] that had been taken up in the second adhesive layer formation step (S12), and the base film [A] was unwound at a conveying speed of 20 m / min. At this time, the first adhesive layer composition [2] was applied to the other surface of the base film [A] on which the second adhesive layer was not formed, using a vacuum extrusion die coater, and dried and cured in an atmosphere of 120°C to form a first adhesive layer with a thickness of 320 nm. In addition, while being conveyed at the same conveying speed of 20 m / min as above, a carrier film [A] was attached to the first adhesive layer and then wound up.

[0414] The first adhesive layer is formed by the same process as the second adhesive layer described above, and the resin type, inorganic particle type, average particle size, and thickness of the adhesive layer are all the same, so it is adhesive layer [C].

[0415] [5] Step of forming multiple cured layers The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up.

[0416] [Preparation of Laminate Film [6]] [1], [2] Preparation of Protective Film and Carrier Film, and Preparation of Base Film As the protective film and carrier film, a protective film [1] and a carrier film [A] similar to those used in the laminate film [1] were prepared. In addition, a film similar to the base film [A] used in the preparation of the laminate film [1] was prepared, except that the thermal shrinkage of the laminate portion was appropriately adjusted in the second-stage stretching step to the values ​​shown in Table V.

[0417] [3], [4] Steps of forming second and first adhesive layers The second adhesive layer and the first adhesive layer were not formed.

[0418] [5] Step of forming multiple cured layers The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up.

[0419] [Preparation of Laminate Film [7]] [1], [2] Preparation of Protective Film and Carrier Film, and Preparation of Base Film The following protective film [1] and carrier film [B] were prepared. In addition, a film similar to the base film [A] used in the preparation of the laminate film [1] was prepared, except that the thermal shrinkage of the laminate portion in the second-stage stretching step was appropriately adjusted to the values ​​shown in Table VI.

[0420] Protective film [1]: Polyester film "Tretec 7832C" (thickness 30 μm, manufactured by Toray Advanced Film Co., Ltd.) Carrier film [B]: Polyethylene terephthalate film "NSA22T" (thickness 25 μm, manufactured by San-ei Kaken Co., Ltd.)

[0421] [3] Step of forming second adhesive layer The second adhesive layer was formed in the same manner as for the laminated film [1], except that the thickness of the second adhesive layer was set to 50 μm, and the protective film [1] was attached and wound up. Hereinafter, this adhesive layer will be referred to as adhesive layer [D].

[0422] [4] Step of forming first adhesive layer The first adhesive layer (adhesive layer [A]) was formed in the same manner as in the laminated film [1], and the carrier film [B] was attached and wound up.

[0423] [5] Step of forming multiple cured layers The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up.

[0424] [Preparation of Laminate Film [8]] [1], [2] Preparation of Protective Film and Carrier Film, and Preparation of Base Film The following protective film [1] and carrier film [C] were prepared. In addition, a film similar to the base film [A] used in the preparation of the laminate film [1] was prepared, except that the thermal shrinkage of the laminate portion in the second-stage stretching step was appropriately adjusted to the values ​​shown in Table VI.

[0425] Protective film [1]: Polyester film "Tretec 7832C" (thickness 30 μm, manufactured by Toray Advanced Film Co., Ltd.) Carrier film [C]: Polyethylene terephthalate film "NSA22T" (thickness 38 μm, manufactured by San-ei Kaken Co., Ltd.)

[0426] [3] Step of forming second adhesive layer The second adhesive layer was formed in the same manner as for the laminated film [1], except that the thickness of the second adhesive layer was set to 500 μm, and the protective film [1] was attached and wound up. Hereinafter, this adhesive layer will be referred to as adhesive layer [E].

[0427] [4] Step of forming first adhesive layer The first adhesive layer (adhesive layer [A]) was formed in the same manner as in the laminated film [1], and the carrier film [C] was attached and wound up.

[0428] [5] Step of forming multiple cured layers The first cured layer was formed by preparing a coating solution of a cured layer composition using the same components of prescription A1 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up. The second cured layer was also formed by preparing a coating solution of a cured layer composition using the same components of prescription A3 as in the laminate film [1], applying the coating solution, drying, and UV curing, and then winding up.

[0429] [Preparation of Laminated Films [9],

[10] , and

[11] ] Laminated films [9],

[10] , and

[11] were prepared in the same manner as laminated film [1], except that in the second-stage stretching step, the thermal shrinkage of the laminate portion was appropriately adjusted to the values ​​shown in Table VI.

[0430] [Production of Laminated Film

[12] ] [1] to [4] Preparation of Protective Film and Carrier Film, Production of Base Film, and Steps of Forming Second Adhesive Layer and First Adhesive Layer The steps of preparing the protective film and carrier film, production of the base film, and formation of the second adhesive layer and the first adhesive layer were carried out in the same manner as for Laminated Film [1], except that in the second-stage stretching step, the thermal shrinkage rate of the laminate portion was appropriately adjusted to the values ​​in Table VI. Then, the base film with protective film [1] and carrier film [A] attached was wound up.

[0431] [5] Step of forming multiple cured layers In the production of the laminated film

[12] , two cured layers were formed as multiple cured layers.

[0432] [5-1] Step of forming first cured layer [5-1-1] Preparation of coating liquid of cured layer composition A coating liquid of a cured layer composition was prepared by mixing and stirring the following components. This coating liquid of a cured layer composition is designated as "coating liquid [3] of a cured layer composition." The content of beads in the following components was adjusted so that the mass of the beads in the following components was 70 parts by mass when the total mass of the coating liquid [3] of a cured layer composition described below was taken as 100 parts by mass.

[0433] <Ingredients: Formulation B1> "KAYARAD PET-30" (binder resin) 19.4 parts by mass "Irgacure 184" (polymerization initiator) 0.6 parts by mass "Seikabeam 10-28" (silicone leveling agent) 0.03 parts by mass Methyl isobutyl ketone (solvent) 1129.6 parts by mass Beads: "GM-0806S" (contents listed above) Microparticle dispersion "MZ-230X" 51.0 parts by mass

[0434] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0435] The beads "GM-0806S" in the above component are polyacrylic ester, have a refractive index of 1.49, and a number-average particle size of 8 μm.

[0436] The fine particle dispersion "MZ-230X" in the above components is a high refractive index ZrO ２ It is a methyl ethyl ketone dispersion of fine particles, and the solid content is 32.5% by mass.

[0437] [5-1-2] Application of curable layer composition, and curing and drying The protective film [1] was peeled off from the base film [A] with the protective film [1] and carrier film [A] that had been taken up in the second adhesive layer formation step (S13), and the film was unwound at a conveying speed of 20 m / min. The protective film [1] on the second adhesive layer side attached to the base film [A] was peeled off, and a coating liquid [3] of the curable layer composition was applied to the surface on the second adhesive layer side, dried and UV-cured, and taken up.

[0438] [5-2] Step of forming second cured layer [5-2-1] Preparation of coating liquid of cured layer composition The following components were mixed and stirred to prepare a coating liquid of a cured layer composition. This coating liquid of a cured layer composition is referred to as "coating liquid [4] of cured layer composition."

[0439] <Components: Formulation B2> "KAYARAD PET-30" (binder resin) 19.4 parts by mass "Irgacure 184" (polymerization initiator) 0.6 parts by mass "Seikabeam 10-28" (silicone leveling agent) 0.03 parts by mass Methyl isobutyl ketone (solvent) 1129.6 parts by mass Fine particle dispersion "MZ-230X" 51.0 parts by mass

[0440] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0441] The fine particle dispersion "MZ-230X" in the above components is a high refractive index ZrO ２ It is a methyl ethyl ketone dispersion of fine particles, and the solid content is 32.5% by mass.

[0442] [5-2-2] Application of cured layer composition, and curing and drying The base film [A] with the carrier film [A] wound up in the step of forming the first cured layer and the first cured layer formed thereon was unwound at a conveying speed of 20 m / min. The coating liquid [4] of the cured layer composition was applied to the surface of the first cured layer side, dried, UV-cured, and wound up. A laminated film

[12] was produced by the above steps.

[0443] [Production of Laminated Film

[13] ] [1] to [4] Preparation of Protective Film and Carrier Film, Production of Base Film, and Steps of Forming Second Adhesive Layer and First Adhesive Layer The preparation of the protective film and carrier film, production of the base film, and steps of forming the second adhesive layer and the first adhesive layer were carried out in the same manner as for Laminated Film [1], except that in the second-stage stretching step, the thermal shrinkage rate of the laminate portion was appropriately adjusted to the values ​​in Table VII. Then, the base film with protective film [1] and carrier film [A] attached was wound up.

[0444] [5] Step of forming multiple cured layers In the production of the laminated film

[13] , three cured layers were formed as multiple cured layers.

[0445] [5-1] Step of forming the first cured layer For the first cured layer, a coating solution of a composition for the cured layer was prepared using the same components of formulation A1 as in the laminate film [1], and the coating solution was applied, dried, UV-cured, and wound up.

[0446] [5-2] Step of forming second cured layer [5-2-1] Preparation of coating liquid of cured layer composition The following components were mixed and stirred to prepare a coating liquid of a cured layer composition. This coating liquid of a cured layer composition is referred to as "coating liquid [5] of cured layer composition."

[0447] <Components: Formulation A2> "KAYARAD PET-30" (binder resin) 23.8 parts by mass "Irgacure 184" (polymerization initiator) 0.6 parts by mass "Seikabeam 10-28" (silicone leveling agent) 0.03 parts by mass Methyl isobutyl ketone (solvent) 1138.6 parts by mass Fine particle dispersion "MZ-230X" 37.7 parts by mass

[0448] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0449] The fine particle dispersion "MZ-230X" in the above components is a high refractive index ZrO ２ It is a methyl ethyl ketone dispersion of fine particles, and the solid content is 32.5% by mass.

[0450] [5-2-2] Application of cured layer composition, and curing and drying The base film [A] with the carrier film [A] wound up in the step of forming the first cured layer and on which the first cured layer was formed was unwound at a conveying speed of 20 m / min. A coating solution [5] of the cured layer composition was applied to the surface on the side of the first cured layer, dried and UV-cured, and then wound up.

[0451] [5-3] Step of forming third cured layer [5-3-1] Preparation of coating liquid of cured layer composition The components of the above-mentioned formulation A3 were mixed and stirred to prepare a coating liquid of the cured layer composition. This coating liquid of the cured layer composition is referred to as "coating liquid [6] of cured layer composition."

[0452] [5-3-2] Application of cured layer composition, and curing and drying The base film [A] with the carrier film [A] wound up in the step of forming the second cured layer and on which the first and second cured layers were formed was unwound at a conveying speed of 20 m / min. A coating solution [6] of the cured layer composition was applied to the surface on the side of the second cured layer, dried and UV-cured, and then wound up.

[0453] [Preparation of Laminate Films

[14] and

[15] ] [1] to [4] Preparation of Protective Film and Carrier Film, Preparation of Base Film, and Steps of Forming Second Adhesive Layer and First Adhesive Layer The preparation of the protective film and carrier film, preparation of the base film, and steps of forming the second adhesive layer and the first adhesive layer were carried out in the same manner as for Laminate Film [1], except that in the second-stage stretching step, the thermal shrinkage rate of the laminate portion was appropriately adjusted to the values ​​in Table VII. Then, the base film with protective film [1] and carrier film [A] attached was wound up.

[0454] [5] Process for forming multiple cured layers In the production of laminate films

[14] and

[15] , two cured layers were formed as multiple cured layers. For both laminate films

[14] and

[15] , a coating solution of a cured layer composition was prepared using the same components of formulation A1 as for laminate film [1], and the coating solution was applied, cured, dried, and then wound up. For the second cured layer, a coating solution of a cured layer composition was prepared using the components of formulation A4 below for laminate film

[14] , and for laminate film

[15] , a coating solution of a cured layer composition was prepared using the components of formulation B2 described above, and the coating solution was applied, dried, and UV-cured to form the second cured layer, and then wound up.

[0455] <Ingredients: Formulation A4> "KAYARAD PET-30" (binder resin) 23.8 parts by weight "Irgacure 184" (polymerization initiator) 0.6 parts by weight "Seikabeam 10-28" (silicone leveling agent) 0.03 parts by weight Methyl isobutyl ketone (solvent) 1138.6 parts by weight Beads: "GM-0806S" (contents listed above) Fine particle dispersion "MZ-230X" 20.0 parts by weight

[0456] In the above 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 Dainichiseika Color & Chemicals Mfg. Co., Ltd., with a solid content of 10%.

[0457] The beads "GM-0806S" in the above component are polyacrylic ester, have a refractive index of 1.49, and a number-average particle size of 8 μm.

[0458] The fine particle dispersion "MZ-230X" in the above components is a high refractive index ZrO ２ It is a methyl ethyl ketone dispersion of fine particles, and the solid content is 32.5% by mass.

[0459] [Summary of materials, layer types, and formulations for producing laminated films] The types of carrier film, base film, and adhesive layer used in the laminated films produced by the above process, as well as the formulation of the components of the coating solution for the cured layer composition, are shown in Tables I to IV below.

[0460]

[0461]

[0462]

[0463]

[0464] [Various Measurements] The thickness of each adhesive layer, substrate film, and cured layer of the laminated film produced by the above steps was measured by the method described in the micrometer section of JIS B 7502. Specifically, the thickness of a portion of the film or layer was measured at 10 random locations, and the arithmetic mean value of the measured values ​​at the 10 locations was calculated, and this arithmetic mean value was defined as the thickness of the film or layer.

[0465] The refractive index of the cured layer of the laminated film was measured using the Becke method in accordance with the above-mentioned JIS K 7142:2008 B method (for powder or granular transparent materials).

[0466] The peel adhesive strength [N / 25 mm] of the carrier film from the first adhesive layer was measured by the 180-degree peel test method specified in JIS Z 0237:2009 (Test methods for adhesive tapes and adhesive sheets). Specifically, the laminated film was cut to a size of 25 mm wide and 100 mm long, and after leaving it under conditions of 25°C and 50% RH for 2 hours, the peel adhesive strength [N / 25 mm] of the carrier film from the first adhesive layer was measured at a speed of 2.3 m / min.

[0467] The heat shrinkage rates of the laminate portion in the longitudinal direction (MD direction) and width direction (TD direction) were measured and calculated as follows.

[0468] First, a test piece was prepared by cutting a piece of the laminate into a width of 100 mm and a length of 100 mm. A cross was made at each of the four corners of the test piece. The pre-heating lengths [mm] of the four central points of the cross cut in the longitudinal direction (MD) and transverse direction (TD) were measured using a CNC three-dimensional measuring machine (product name "LEGEX774") manufactured by Mitutoyo Corporation.

[0469] The laminate is then placed in an oven and heated at 130°C for 90 minutes, then allowed to cool at room temperature for 1 hour, and the lengths (mm) of the four points in the machine direction (MD) and transverse direction (TD) after heating are measured again using the CNC coordinate measuring machine.

[0470] The lengths [mm] before heating and the lengths [mm] after heating in the longitudinal direction (MD direction) and width direction (TD direction) measured at the four points are substituted into the following formula to calculate the heat shrinkage rates in each of the longitudinal direction (MD direction) and width direction (TD direction).

[0471] Heat shrinkage rate [%] = {(length before heating [mm] - length after heating [mm]) / length before heating [mm]} × 100

[0472] [Evaluation] The laminated films prepared as described above were evaluated for optical unevenness and clarity based on the results shown in Tables V to VII below.

[0473] <Optical Unevenness> [Evaluation Method] The laminated film was left to stand for 30 minutes in a room at a temperature of 25°C and a humidity of 65%. A fluorescent lamp was projected onto the film surface from 45° above and 1 m away from the surface on which the number of continuous optical unevenness in the longitudinal direction was counted, and the number of optical unevenness was visually counted and evaluated from 45° below and 0.5 m away from the surface on which the optical unevenness was counted. Note that optical unevenness was evaluated by counting the number of wrinkles in the width direction of the film, with each optical unevenness that was convex in the longitudinal direction of the film relative to the surface being observed being counted as one line.

[0474] [Evaluation criteria] A: The number of optical irregularities is in the range of 0 to 5 lines / m. B: The number of optical irregularities is in the range of 6 to 10 lines / m. C: The number of optical irregularities is in the range of 11 to 19 lines / m. D: The number of optical irregularities is 20 lines / m or more.

[0475] <<Clarity>> [Evaluation Method] The laminated film was divided into 20 sections in the TD direction, excluding 20 mm of the edges, and the clarity of each section was measured using a Hazeguard i manufactured by BYK in accordance with ASTM D1003. Clarity was evaluated based on the difference between the maximum and minimum values.

[0476] [Evaluation criteria] A: The difference between the maximum and minimum values ​​is less than 0.5. B: The difference between the maximum and minimum values ​​is 0.5 or more and less than 1.0. C: The difference between the maximum and minimum values ​​is 1.0 or more and less than 1.5. D: The difference between the maximum and minimum values ​​is 1.5 or more and less than 2.0. E: The difference between the maximum and minimum values ​​is 2.0 or more.

[0477] [Fabrication of display device and performance confirmation] When the carrier film [A] was peeled off from the laminated film [1] and attached to the surface of an existing OLED device, it was confirmed that the OLED device with the laminated film [1] attached had a more uniformly improved brightness than the OLED device without the laminated film [1] attached.

[0478] <<General Comments>> As is clear from Tables V to VII, the laminated film of the present invention is less susceptible to heat shrinkage than the comparative examples, and is capable of suppressing optical unevenness and reducing deterioration in clarity.

[0479]

[0480]

[0481]

[0482] It is possible to provide a laminated film that is resistant to thermal shrinkage, suppresses optical unevenness, and suppresses deterioration of clarity, as well as a method for producing the same and a display device.

[0483] REFERENCE SIGNS LIST 1, 1a Stirring device (stirring tank) 2 Casting die 3 Support (endless belt, drum) 3a, 3b Roller 4 Peeling roller 5 Web (casting film) 6 Stretching device (tenter stretching device, oblique stretching device) 7 Drying device 8 Cutting section 9 Winding device 10 Stretching device 11 Cutting section 12 Winding device 14 Extruder 15 Casting die 16 Cast drum, support 16a Touch roller 17 Cooling drum 18 Stretching device (tenter stretching device) 19 Cutting section 20 Winding device 21 Stretching device (tenter stretching device) 22 Cutting section 23 Winding device 40 Stretching device (tenter stretching device) 42 Clip 46 Cover 48 Endless chain 50 Driving sprocket 52 Driven sprocket 54 Rail 56 Release member 80 Temperature distribution sensor 101 Nozzle fixing portion 102 Nozzle 103 Web (cast film) 104 End nozzle 105 Center nozzle 106 Clip cover F Film F1, F2 Laminated film SF Base film CF Carrier film AL1 First adhesive layer AL2 Second adhesive layer L1, L2, L3 Hardened layer LL Low refractive index layer LH High refractive index layer Ip Inorganic particles Op Beads

Claims

1. A laminated film comprising, in this order, a carrier film, a first adhesive layer, a base film, a second adhesive layer, and a plurality of cured layers, wherein the first adhesive layer and the second adhesive layer contain at least inorganic particles and a polyolefin resin, and the thermal shrinkage of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer is measured under conditions of 130°C for 90 minutes, and when the thermal shrinkage in the longitudinal direction and the width direction are X and Y, respectively, the X and Y satisfy the following formulas (1) and (2), Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%]. The laminated film further comprises: the base film contains a cycloolefin resin; beads are contained between the plurality of cured layers; and the plurality of cured layers have a refractive index difference.

2. The laminated film according to claim 1, characterized in that the carrier film contains at least polyethylene terephthalate, and the peel adhesive strength of the carrier film with respect to the first adhesive layer is within the range of 0.1 to 0.4 [N / 25 mm].

3. The laminated film according to claim 1, wherein the first adhesive layer and the second adhesive layer contain the same compound and have the same thickness.

4. The laminated film according to claim 1, characterized in that the refractive indexes of the multiple cured layers gradually increase from the substrate side toward the outermost layer side.

5. A method for producing a laminated film according to any one of claims 1 to 4, comprising the step of measuring the thermal shrinkage of a laminate portion consisting of the first adhesive layer, the base film, and the second adhesive layer under conditions of 130°C for 90 minutes, and adjusting X and Y so that the thermal shrinkage in the longitudinal direction and the transverse direction satisfy the following formulas (1) and (2): Formula (1): Y<X [%] Formula (2): 0.004<{(X+Y) / 2}<0.16 [%].

6. A display device equipped with an optical film, characterized in that the display device comprises a portion of the laminate film according to any one of claims 1 to 4 excluding the carrier film as the optical film.

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