Hard coat film

Abstract

The hard coat film 10 comprises a substrate 11 and a hard coating layer 12 made of a cured product of a resin composition containing a resin (A) and a resin (B) and laminated on the substrate 11, the resin (A) being a polyfunctional (meth)acrylic monomer having a weighted average functionality of 4 or more. The resin (B) is an aliphatic urethane acrylate. The glass transition temperature Tg of the hard coating layer 12 is 50°C or more and 100°C or less. When the loss tangent tanδ of the hard coating layer 12 is measured by dynamic viscoelasticity measurement in which a dynamic load of a frequency of 1 Hz is applied, the loss tangent tanδ at the glass transition temperature Tg is 0.07 or more and 0.15 or less.

Description

Technical Field

[0001] The present disclosure relates to a hard coat film.

Background Art

[0002] Display devices such as liquid crystal displays (LCDs), plasma displays (PDPs), or organic EL displays (OLEDs) are widely used in smartphones, mobile phones, portable personal computers, car navigation devices, and the like. Generally, a protective film for preventing damage to the screen is provided on the outermost surface of the screen of the display device. The protective film includes a base material and a hard coating layer laminated on the base material. Conventional hard coating layers are formed of materials having a high crosslink density.

[0003] Currently, the development of flexible display devices having a flexible screen and capable of being folded is underway. A flexible display device is required to be repeatedly foldable a large number of times, such as hundreds of thousands of times, in one or more directions. Therefore, the protective film covering the screen of the flexible display device is also required to have flexibility that can withstand the repeated folding over the above-mentioned large number of times.

[0004] However, the material having a high crosslink density used for the conventional hard coating layer is hard but lacks flexibility because it has a high shrinkage rate. Therefore, when a flexible display device covered with a protective film having a conventional hard coating layer is repeatedly folded a large number of times, such as hundreds of thousands of times, the hard coating layer and the protective film are likely to peel off from the screen. Further, when the crosslink density of the material of the hard coating layer is high, even if the thickness of the hard coating layer itself is thin, the hard coating layer becomes brittle or cracks are likely to occur in the hard coating layer.

[0005] Therefore, as a flexible hard coating layer, for example, Patent Document 1 discloses a hard coating layer with a thickness of 5 μm that can be bent around a mandrel with a diameter of 2 mm without cracking. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Publication No. 2009 / 0004478 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 mentioned above does not disclose anything about repeatedly folding the hard coating layer hundreds of thousands of times, nor does it disclose the materials or properties of the hard coating layer necessary for such repeated folding.

[0008] Furthermore, if the hard coating layer is formed from a flexible material to allow for multiple folds, the scratch resistance of the hard coating layer decreases, making it more susceptible to damage. Therefore, the hard coating layer used in protective films for flexible display devices requires not only the ability to withstand the numerous and repeated folds mentioned above, but also scratch resistance to prevent damage.

[0009] Therefore, the present invention has been made in view of the above problems, and aims to provide a hard coat film that has the ability to withstand repeated folding many times and also has scratch resistance. [Means for solving the problem]

[0010] To solve the above problems, according to one aspect of the present invention, Substrate and A hard coating layer laminated on the substrate, comprising a cured product of a resin composition containing resin (A) and resin (B), Equipped with, The resin (A) is a polyfunctional (meth)acrylic monomer having 4 or more weighted average functional groups. The aforementioned resin (B) is an aliphatic urethane acrylate, The content of the resin (A) in the resin composition is 20% by mass or more and 40% by mass or less. The content of the resin (B) in the resin composition is 2% by mass or more and 15% by mass or less. The resin composition further comprises metal oxide nanoparticles having an average particle size of 100 nm or less, and a fluorine compound. The glass transition temperature Tg of the hard coating layer is 50°C or higher and 100°C or lower. A hard coat film is provided in which, when the loss tangent tanδ of the hard coating layer is measured by dynamic viscoelasticity measurement with a dynamic load applied at a frequency of 1 Hz, the loss tangent tanδ at the glass transition temperature Tg is 0.07 or more and 0.15 or less.

[0012] In one embodiment, the content of the metal oxide nanoparticles in the resin composition may be 2% by mass or more and 5% by mass or less with respect to the total solid content of the resin composition of the hard coating layer.

[0013] The metal oxide constituting the metal oxide nanoparticles may be either silica or alumina, or both.

[0014] The metal oxide nanoparticles may have a Mohs hardness greater than 6.

[0015] When a wear tester using steel wool #0000 is used to abrade the steel wool against the surface of the hard coating layer under the conditions of load: 1000g, speed: 50mm / sec, reciprocating distance: 40mm, and number of reciprocations: 2500, the water contact angle of the surface of the hard coating layer after abrasion may be greater than 100 degrees.

[0016] In one embodiment, the water contact angle of the surface of the hard coating layer before wear may be greater than 110 degrees.

[0017] In one embodiment, the reduction rate of the water contact angle after wear with respect to the water contact angle before wear on the surface of the hard coating layer may be less than 13%.

[0018] In one embodiment, the content of the resin (A) contained in the resin composition may be greater than twice and less than nine times the content of the resin (B).

[0020] The hard coat film may be configured to be foldable by either bending in or bending out at least 100,000 times without generating at least any one of cracking, delamination, and loss of optical properties.

[0021] The base material may be a thermoplastic base material having a thickness of 10 μm or more and 200 μm or less.

[0022] The resin composition The above included in Fluorine compound but on the surface side of the hard coating layer biased towards may be analyzed.

[0023] Furthermore, the segregated fluorine compound may have an antifouling function.

[0025] In one embodiment [[ID=3४]] ,before The optical properties are one or more selected from the group consisting of variations in total light transmittance (%), transmission haze, glossiness, and chromaticity b* (intensity of color from blue to yellow). You can .

[0026] In one embodiment, The fluorine compound contained in the resin composition is the base material of the hard coating layer beside may ,side not be segregated.

Advantages of the Invention

[0027] According to embodiments of the present invention, it is possible to provide a hard coat film that possesses both the ability to withstand repeated folding over numerous times and scratch resistance. [Brief explanation of the drawing]

[0028] [Figure 1] Figure 1 is a cross-sectional view showing a hard coat film according to one embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing a hard coat film according to another embodiment of the present invention. [Figure 3] Figure 3 is a cross-sectional view showing a hard coat film according to another embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram showing a hard coat film manufacturing apparatus according to the same embodiment. [Modes for carrying out the invention]

[0029] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and specific numerical values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations. Elements not directly related to the present invention are omitted from the illustrations.

[0030] Please note that in the drawings referenced in the following explanation, the size of some components may be exaggerated for illustrative purposes. Therefore, the relative sizes of the components shown in each drawing do not necessarily accurately represent the actual proportional relationships between the components.

[0031] [1. Overall composition of the hard coat film] First, with reference to Figure 1, the overall configuration of the hard coat film 10 according to one embodiment of the present invention will be described. Figure 1 is a cross-sectional view showing the hard coat film 10 according to this embodiment.

[0032] The hard coat film 10 according to this embodiment is provided on the outermost surface of a flexible display device, for example, as a protective film to prevent scratches. As shown in Figure 1, the hard coat film 10 according to this embodiment comprises a substrate 11 and a hard coating layer 12. The hard coating layer 12 is laminated on the substrate 11. Each layer will be described below.

[0033] [Base material 11] The substrate 11 is formed from, for example, a transparent material capable of transmitting light in the visible light range having wavelengths of 350 to 830 nm.

[0034] The base material 11 may be composed of, for example, an inorganic material such as a glass film, or an organic material such as a plastic film.

[0035] The material of the plastic film is, for example, one or more selected from the group consisting of polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, poly(meth)acrylate resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins, and preferably one or more of polyester resins, acetate resins, polycarbonate resins, polyimide resins, and polyolefin resins.

[0036] The thickness of the substrate 11 is preferably, for example, 10 μm or more and 200 μm or less, more preferably 20 μm or more and 100 μm or less, and even more preferably 40 μm or more and 60 μm or less, from the viewpoint of handling, flexibility, cost, and properties.

[0037] If the thickness of the substrate 11 is 10 μm or more, at least one of the following advantages is obtained. Since the rigidity of the substrate 11 itself can be ensured, wrinkles are less likely to occur in the hard coat film 10 even when stress is applied to the hard coat film 10. In addition, even if the hard coating layer 12 is continuously formed on the substrate 11, wrinkles are less likely to occur in the hard coat film 10, thus reducing manufacturing problems for the hard coat film 10. Furthermore, since curling of the hard coat film 10 is reduced, it becomes unnecessary to laminate an additional coating layer on the back surface of the substrate 11. The back surface of the substrate 11 is the surface opposite to the surface on which the hard coating layer 12 is laminated.

[0038] When using rolls during the manufacture of the hard coat film 10, the thickness of the base material 11 is preferably 200 μm or less. A base material thickness of 200 μm or less makes it easier to wind the hard coat film 10, both during and after manufacture, into a roll, allowing for efficient production of the hard coat film 10. Furthermore, the base material 11 is preferably a thermoplastic base material.

[0039] The substrate 11 may be pre-treated for purposes such as improving adhesion. The surface treatment may include, for example, one or more treatments from among corona treatment, plasma treatment, ultraviolet treatment, excimer treatment, and primer treatment. For improved adhesion, surface treatment using a silane coupling agent is particularly desirable. Furthermore, before forming the hard coating layer 12 on the substrate 11, it is preferable to remove dust and clean the surface of the substrate 11 with a web cleaner or the like, if necessary.

[0040] [Hard coating layer 12] The hard coating layer 12 is provided on the substrate 11. The hard coating layer 12 may be, for example, a cured product of a resin composition. In this embodiment, the resin composition comprises resin (A), resin (B), an energy ray activated polymerization initiator, and a solvent.

[0041] Resin (A) and resin (B) may be energy-ray curable resins such as ultraviolet-curable resins, electron beam-curable resins, or infrared-curable resins. It is preferable to use ultraviolet-curable resins for resin (A) and resin (B) because this eliminates the need for post-curing treatment. Furthermore, curing under a nitrogen atmosphere is desirable to ensure proper curing.

[0042] Resin (A) may be a polyfunctional (meth)acrylic monomer having 4 or more weighted average functional groups. Preferably, the number of weighted average functional groups of resin (A) is greater than 4.2 and less than 5.1. In this embodiment, resin (A) includes, for example, a difunctional acrylic monomer and a hexafunctional acrylic monomer. Examples of difunctional acrylic monomers include SARTOMER's product "SR833S" (difunctional tricyclodecanedimethanol diacrylate) and product "SR306" (tripropylene glycol diacrylate). Examples of hexafunctional acrylic monomers include DAIEL-ALLNEX LTD.'s product "DPHA" (dipentaerythritol hexaacrylate). Here, at least one of a trifunctional acrylic monomer, a tetrafunctional acrylic monomer, or a pentafunctional acrylic monomer may be used instead of, or in addition to, a difunctional acrylic monomer. Examples of trifunctional monomers include "SR351" (trimethylolpropane triacrylate) or "SR454" (ethoxylated trimethylolpropane triacrylate), both of which are available from SARTOMER. Examples of tetrafunctional monomers include "SR295" (pentaerythritol tetraacrylate), "SR355" (di-trimethylolpropane tetraacrylate), or "SR494" (ethoxylated pentaerythritol tetraacrylate), all of which are available from SARTOMER. An example of a pentafunctional monomer is "SR399" (dipentaerythritol pentaacrylate), both of which are available from SARTOMER.

[0043] In this embodiment, resin (B) is an aliphatic urethane acrylate. Resin (B) is, for example, a trifunctional aliphatic urethane acrylate or a trifunctional aliphatic polyester urethane acrylate. Specific examples of resin (B) available on the market include, for example, SARTOMER's product "CN989" (trifunctional aliphatic urethane acrylate) and product "CN929" (trifunctional aliphatic polyester urethane acrylate).

[0044] By constructing the hard coating layer 12 from a cured product of a resin composition containing a resin (A) which is a polyfunctional (meth)acrylic monomer with 4 or more weighted average functional groups and a resin (B) which is an aliphatic urethane acrylate, the glass transition temperature Tg of the hard coating layer 12 can be set to 50°C or higher and 100°C or lower. Furthermore, by using the same configuration for the hard coating layer 12, the loss tangent tanδ of the hard coating layer 12 at the glass transition temperature Tg can be set to 0.07 or higher and 0.15 or lower. The loss tangent tanδ of the hard coating layer 12 at the glass transition temperature Tg is a value calculated by dynamic viscoelasticity measurement with a dynamic load applied at a frequency of 1 Hz. Also, the loss tangent tanδ is the ratio of the storage modulus (E') to the loss modulus (E') (tanδ = E' / E'). The storage modulus (E') is the component of internal energy increase when strain occurs in the object. The storage modulus (E') indicates the elastic properties of the object. The loss modulus (E') is the energy loss component when strain occurs in an object. This loss energy is the energy that diffuses out of the object as heat. The loss modulus (E') indicates the viscous properties of the object.

[0045] If the glass transition temperature Tg is below 50°C, the hard coating layer 12 will soften in high-temperature environments such as inside a vehicle, significantly reducing its scratch resistance. On the other hand, if the glass transition temperature Tg is above 100°C, the flexibility of the hard coating layer 12 cannot be ensured, making it difficult to repeatedly fold the hard coating layer 12 many times.

[0046] Therefore, it is preferable to set the glass transition temperature Tg of the hard coating layer 12 to 50°C or higher and 100°C or lower. This improves the scratch resistance of the hard coating layer 12 even in high-temperature environments such as inside a vehicle, and also allows the hard coating layer 12 to be repeatedly folded over a large number of times, such as 100,000 times or more.

[0047] If the loss tangent tanδ of the hard coating layer 12 at the glass transition temperature Tg is less than 0.07, the hardness of the hard coating layer 12 becomes too high, reducing its flexibility. On the other hand, if the loss tangent tanδ of the hard coating layer 12 at the glass transition temperature Tg is greater than 0.15, the hardness of the hard coating layer 12 becomes too low, reducing its scratch resistance.

[0048] Therefore, it is preferable to set the loss tangent tanδ of the hard coating layer 12 at the glass transition temperature Tg to 0.07 or more and 0.15 or less. This improves the scratch resistance of the hard coating layer 12 and also allows the hard coating layer 12 to be repeatedly folded over a large number of times, such as 100,000 times or more.

[0049] The content (mass%) of resin (A) in the resin composition is preferably greater than twice and less than nine times the content (mass%) of resin (B), more preferably four times or more and less than nine times, and even more preferably four times or more and five times. The content of resin (A) in the resin composition is preferably 20% by mass or more and 40% by mass or less, and more preferably 26% by mass or more and 33% by mass or less. The content of resin (B) in the resin composition is preferably 2% by mass or more and 15% by mass or less, and more preferably 4.5% by mass or more and 11.5% by mass or less.

[0050] In this embodiment, the energy ray-activated polymerization initiator is a Norrish type I photoinitiator or a Norrish type II photoinitiator. Specific examples of energy ray-activated polymerization initiators available on the market include IGM Resins' (formerly BASF) products "OMNIRAD 184 (IRGACURE 184)" (1-hydroxycyclohexyl phenyl ketone), "OMNIRAD 500 (IRGACURE 500)" (a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone), and "OMNIRAD TPO" (2,4,6-trimethylbenzoyldiphenylphosphine oxide).

[0051] The solvent is not particularly limited as long as it satisfies the coatability of the resin composition, but it is preferable to select it with safety in mind. In this embodiment, the solvent includes one or more selected from the group consisting of, for example, alcohol-based solvents such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and diacetone alcohol; ketone-based solvents such as acetone, methyl ethyl ketone (hereinafter MEK), methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate (hereinafter PGMEA); and ether-based solvents such as propylene glycol monomethyl ether (hereinafter PGME), diethyl ether, and diisopropyl ether. Preferably, it includes one of MEK, PGME, and PGMEA. It is particularly preferable to use either one or both of PGME and PGMEA, which can improve the coatability of the resin composition.

[0052] The thickness of the hard coating layer 12 is preferably 3 μm or more, and more preferably 5 μm or more. When the thickness of the hard coating layer 12 is 3 μm or more, sufficient hardness is obtained, making it less likely for scratches to occur on the hard coating layer 12 during the manufacturing process. Furthermore, the thickness of the hard coating layer 12 is preferably 15 μm or less, and more preferably 10 μm or less. When the thickness of the hard coating layer 12 is 15 μm or less, microcracks in the hard coating layer 12 that occur when the hard coat film 10 is bent during manufacturing are less likely to occur, resulting in good productivity of the hard coat film 10.

[0053] The resin composition of the hard coating layer 12 may contain dispersed metal oxide nanoparticles. Including metal oxide nanoparticles in the resin composition can increase the hardness of the hard coating layer 12.

[0054] Furthermore, the average particle size of the metal oxide nanoparticles is preferably 100 nm or less, and more preferably 50 nm or less. In this embodiment, the average particle size refers to the value measured by the BET method.

[0055] If the average particle size of the metal oxide nanoparticles is greater than 100 nm, the light transmittance of the hard coating layer 12 in the visible light range may decrease. Therefore, by keeping the average particle size of the metal oxide nanoparticles at 100 nm or less, the light transmittance of the hard coating layer 12 in the visible light range can be maintained. These advantages can be further realized by keeping the average particle size of the metal oxide nanoparticles at 50 nm or less. If the substrate 11 is an opaque substrate, the light transmittance of the hard coating layer 12 does not need to be high, so the average particle size of the metal oxide nanoparticles may be greater than 100 nm.

[0056] The content of metal oxide nanoparticles (excluding monomers) in the resin composition is preferably 2% by mass or more and 5% by mass or less, relative to the total solid content of the resin composition of the hard coating layer 12. If the content of metal oxide nanoparticles is greater than 5% by mass, the hard coating layer 12 tends to become brittle. Therefore, by keeping the content of metal oxide nanoparticles in this embodiment within the above range, the flexibility of the hard coating layer 12 can be maintained. The solid content of the resin composition includes all components other than the solvent, and liquid monomer components are also included in the solid content.

[0057] In this embodiment, the metal oxide constituting the metal oxide nanoparticles is either SiO2 (silica) or Al2O3 (alumina), or both. This prevents a decrease in the visible light transmittance of the hard coating layer 12.

[0058] It is preferable that the metal oxide nanoparticles have a Mohs hardness greater than 6. This makes it possible to increase the hardness of the hard coating layer 12 without reducing the flexibility of the hard coating layer 12.

[0059] [Anti-fouling layer 13] In other embodiments of the present invention, an antifouling layer 13 may be provided as part of the hard coating layer 12. Figure 2 is a cross-sectional view showing a hard coat film 10 according to another embodiment of the present invention. As shown in Figure 2, the fluorine compound contained in the hard coating layer 12 forms the antifouling layer 13 by segregating in a first region 12a located on the surface side of the hard coating layer 12. The fluorine compound does not segregate in a second region 12b located on the substrate 11 side of the hard coating layer 12. In other words, the amount of fluorine compound in the second region 12b is less than the amount of fluorine compound in the first region 12a. The second region 12b may contain a fluorine compound. The fluorine compound may be dispersed (discrete) in the second region 12b. The first region 12a has a maximum thickness Ta of, for example, 10% of the total thickness T of the hard coating layer 12. The second region 12b is the region of the hard coating layer 12 other than the first region 12a. In this specification, "segregation" means that, during the curing of the resin composition, the distribution of fluorine compounds in the resin composition is greater on the surface side of the hard coating layer 12 than on the substrate side 11. The antifouling layer 13 prevents contamination of the hard coating layer 12. Depending on the segregation state of the fluorine compounds, the antifouling layer 13 may or may not be a strictly dense layer.

[0060] The antifouling layer 13 contains a fluorine compound. The fluorine compound preferably has a (meth)acrylic group. Furthermore, from the viewpoint of environmental regulations, a perfluoropolyether derivative is preferred over a fluoroalkyl derivative as the fluorine compound. The fluorine compound may also be a hybrid material of organic and inorganic materials. An example of such a hybrid material is fluorine-containing silsesquioxane. In this embodiment, because the antifouling layer 13 contains a fluorine compound, the antifouling and chemical resistance of the hard coat film 10 can be improved. Chemical resistance refers to, for example, resistance to acids, bases, solvents, and oils.

[0061] Examples of fluorine compounds included in the antifouling layer 13 include "KY-1203" from Shin-Etsu Chemical Co., Ltd., "Optoul DAC-HP" from Daikin Industries, Ltd., "Fluorolink AD1700" from Solvay Specialty Polymers, and "CN4000" from SARTOMER.

[0062] [2. Characteristics of the hard coating layer 12] Next, the characteristics of the hard coating layer 12 according to this embodiment will be described. The hard coating layer 12 according to this embodiment has, for example, at least one of the following characteristics (I) to characteristics (IV).

[0063] (I) Glass transition temperature Tg and loss tangent tanδ The glass transition temperature Tg of the hard coating layer 12 is 50°C to 100°C, preferably 60°C to 90°C. The loss tangent tanδ is 0.07 to 0.15, preferably 0.09 to 0.13.

[0064] This improves the scratch resistance and abrasion resistance of the hard coating layer 12 even in high-temperature environments such as inside a vehicle, and also allows the hard coating layer 12 to be repeatedly folded more than 100,000 times.

[0065] The glass transition temperature Tg and loss tangent tanδ can be measured, for example, using a viscoelasticity measuring instrument DMA7100 manufactured by Hitachi High-Tech Science Corporation. The measurement conditions for dynamic viscoelasticity measurements used to calculate the glass transition temperature Tg and loss tangent tanδ are as follows: Sine wave oscillation by frequency: 1Hz Sample size: 20mm (length) x 4.4mm (width) x 0.10mm (thickness) Test method: Temperature increase from 20°C to 200°C at a rate of 10°C / min.

[0066] (II) Number of folds The hard coat film 10 is configured to be folded at least 100,000 times by either bending in or out, without causing at least one of the following: cracking, delamination, or loss of optical properties. Here, optical properties include, for example, variations in total light transmittance (%), transmitted haze, glossiness, and chromaticity b* (intensity of color from blue to yellow). With the above configuration, even when a flexible display device covered with the hard coat film 10 is repeatedly folded hundreds of thousands of times, it is possible to prevent the hard coat film 10 from peeling off the flexible display device.

[0067] The number of folds (folds) can be measured, for example, using a folding test device manufactured by Yuasa System Equipment Co., Ltd. (mandrel diameter 3 mm, bending radius 1.5 mm).

[0068] (III) Water contact angle (WCA) The water contact angle is the angle between the surface of a water droplet and the surface of the hard coating layer 12 when the water droplet is in contact with the surface of the hard coating layer 12. The water contact angle is measured before and after the abrasion test.

[0069] The abrasion test is conducted using an abrasion testing machine with steel wool #0000, where the steel wool is abraded against the surface of the hard coating layer 12 under the following conditions: load: 1000g, speed: 50mm / second, reciprocating distance: 40mm, and number of reciprocating cycles: 2500.

[0070] The water contact angle θ1 of the surface of the hard coating layer 12 before the abrasion test (before abrasion) is preferably greater than 110 degrees and less than 120 degrees. The water contact angle θ2 of the surface of the hard coating layer 12 after the abrasion test (after abrasion) is preferably greater than 100 degrees and less than the water contact angle θ1.

[0071] Before and after wear, the reduction in the water contact angle of the hard coating layer 12 surface is preferably less than 13%, and more preferably 7.6% or less. A low reduction in the water contact angle means that the hard coating layer 12 is hardly worn down even when subjected to an abrasion test, i.e., it has excellent abrasion resistance. Here, the reduction in the water contact angle is calculated using the formula: (water contact angle before abrasion test - water contact angle after abrasion test) ÷ water contact angle before abrasion test × 100.

[0072] The water contact angle can be measured, for example, using an automatic contact angle meter DM-501Hi manufactured by Kyowa Interface Science Co., Ltd.

[0073] (IV) Visible scratches After performing the abrasion test described above on the hard coating layer 12 according to this embodiment, no visible scratches were observed on the hard coating layer 12. In other words, it can be seen that the hard coating layer 12 in the hard coat film 10 according to this embodiment is resistant to scratches and has excellent scratch resistance.

[0074] [3. Manufacturing equipment for hard coat film 10] Figure 4 is a schematic diagram showing a film manufacturing apparatus 100 according to this embodiment. As shown in Figure 4, the film manufacturing apparatus 100 includes a feed roll 110, a winding roll 112, guide rolls 114a to 114d, a coating device 120, a drying device 130, and a curing device 140. In Figure 4, solid arrows indicate the direction of rotation of the rolls. In Figure 4, dashed arrows indicate the direction of transport of the substrate 11.

[0075] A strip-shaped base material 11 is wound in a roll shape on the feed roll 110. The feed roll 110 is arranged so that the base material 11 can be continuously fed out by a guide roll 114a or the like.

[0076] The winding roll 112 is positioned to wind up the strip-shaped hard coat film 10 manufactured by the film manufacturing apparatus 100.

[0077] Guide rolls 114a to 114d are arranged in the transport path within the film manufacturing apparatus 100 so as to be able to transport the strip-shaped substrate 11 and the strip-shaped hard coat film 10. The material of the guide rolls 114a to 114b is appropriately selected according to the desired roll characteristics. Examples of materials for the guide rolls 114a to 114b include metals such as stainless steel, rubber, and silicone resin.

[0078] The coating device 120 is installed between the guide roll 114a and the guide roll 114b. The coating device 120 laminates (for example, coats) the resin composition onto the substrate 11. The coating device 120 is, for example, a gravure coater, a wire bar coater, or a die coater.

[0079] The drying device 130 is installed between the guide rolls 114b and 114c. The drying device 130 heats the substrate 11 coated with the resin composition to dry the resin composition. The drying device 130 vaporizes the solvent contained in the resin composition. This removes the solvent from the resin composition.

[0080] The curing device 140 is installed between the guide roll 114c and the guide roll 114d. The curing device 140 includes guide rolls 144 and 146 and a light source 148 that irradiates the resin composition with energy rays. The energy rays are, for example, electron beams, ultraviolet rays, visible light, gamma rays, etc. The guide rolls 144 and 146 contact the back surface of the substrate 11 to which the resin composition is coated, and feed the substrate 11 in the direction of the guide roll 114d.

[0081] Next, a method for manufacturing a hard coat film 10 using the film manufacturing apparatus 100 will be described. First, the substrate 11 is fed out from the feed roll 110. The fed-out substrate 11 passes under the coating apparatus 120 via the guide roll 114a. The coating apparatus 120 applies the resin composition onto the substrate 11 as it passes under it. The substrate 11 coated with the resin composition is transported to the drying apparatus 130 via the guide roll 114b. The drying apparatus 130 dries the resin composition applied to the substrate 11.

[0082] The substrate 11, on which the dried resin composition is laminated, is transported to the curing device 140 via guide rolls 114c, where energy rays from a light source 148 are irradiated onto the resin composition. This cures the resin composition, producing a hard coat film 10 with a hard coating layer 12 laminated on the substrate 11.

[0083] The hard coat film 10 produced in this way is wound onto the take-up roll 112 via guide rolls 146 and 114d.

[0084] Furthermore, it is preferable that the resin composition contains a fluorine compound. This allows the fluorine compound to float on the resin composition as the solvent dries and rises when the solvent vaporizes in the drying apparatus 130, thereby forming the antifouling layer 13.

[0085] The antifouling layer 13 may also be formed by laminating a layer containing a fluorine compound separately after forming the hard coating layer 12. Figure 3 is a cross-sectional view showing another hard coat film 10 according to this embodiment. As shown in Figure 3, the antifouling layer 13 may be a separate layer from the hard coating layer 12. In this case, the antifouling layer 13 is formed on the hard coating layer 12. When the antifouling layer 13 is formed in a separate process, it can be formed by coating, vapor deposition, sputtering, etc. When using the coating method, an apparatus similar to the film manufacturing apparatus 100 can be used. Thus, the antifouling layer 13 may be a part of the hard coating layer 12, or it may be a separate layer from the hard coating layer 12. [Examples]

[0086] The following sections will specifically describe examples and comparative examples of the present invention. It should be noted that the following examples are merely illustrative, and the hard coat film according to the present invention is not limited to the examples described below.

[0087] Examples 1-13 and Comparative Examples 1-8 were prepared as hard coating layers and antifouling layers. For the preparation of the hard coating layers and antifouling layers, resin compositions containing resin (A), resin (B), an energy ray-activated polymerization initiator, a solvent, and a fluorine compound were prepared. The compositions of the resin compositions for Examples 1-5 are shown in Table 1 below. The compositions of the resin compositions for Examples 6-10 are shown in Table 2 below. The compositions of the resin compositions for Examples 11-13 are shown in Table 3 below. The compositions of the resin compositions for Comparative Examples 1-5 are shown in Table 4 below. The compositions of the resin compositions for Comparative Examples 6-8 are shown in Table 5 below. Note that the units of the mixing ratios in Tables 1-5 are in mass%.

[0088] In addition, the glass transition temperature Tg, loss tangent tanδ (tan Delta, peak) at the glass transition temperature Tg, number of folds, water contact angle (WCA) before and after the abrasion test, and visible scratches were measured for the hard coat films of Examples 1 to 13 and Comparative Examples 1 to 8.

[0089] The glass transition temperature Tg and the loss tangent tanδ at the glass transition temperature Tg were measured using a viscoelasticity measuring instrument DMA7100 manufactured by Hitachi High-Tech Science Corporation. The measurement conditions for dynamic viscoelasticity measurement when calculating the loss tangent tanδ were the same as in the above embodiment.

[0090] The number of folds was measured using a folding test device (mandrel diameter 3 mm, bending radius 1.5 mm) manufactured by Yuasa System Equipment Co., Ltd. Tables 1-5 show the evaluation of the folding test results in three stages. In Tables 1-5, a rating of "3" indicates that there was no change even after 200,000 folds, meaning the evaluation is very good. In Tables 1-5, a rating of "2" indicates that there was no change even after 100,000 folds, meaning the evaluation is within the acceptable range. In Tables 1-5, a rating of "1" indicates that a change occurred before 100,000 folds, meaning the evaluation is poor.

[0091] The water contact angle was measured before and after abrasion using a steel wool abrasion tester, by dropping 2.0 μL of pure water onto the surface of the hard coat film for each experimental example. The abrasion conditions were: load: 1000 g, speed: 50 mm / sec, reciprocating distance: 40 mm, and number of reciprocations: 2500, applied to the surface of the hard coat film. The average value of 10 measurements of the water contact angle at the center of the abraded area was calculated. The water contact angles shown in Tables 1-5 below are average values. The water contact angle was measured using an automatic contact angle meter DM-501Hi manufactured by Kyowa Interface Science Co., Ltd.

[0092] Furthermore, after conducting the abrasion tests described above, we visually inspected the surface of the hard coat film for each experimental example to see if any scratches had occurred.

[0093] [Table 1]

[0094] [Example 1] As shown in Table 1, the resin composition of Example 1 contains 5.64% by mass of SARTOMER's "SR833S" and 22.56% by mass of DAIEL-ALLNEX LTD.'s "DPHA" as resin (A), 9.4% by mass of SARTOMER's "CN989" as resin (B), 5.64% by mass of IGM RESINS' "OMNIRAD500" and 1.41% by mass of IGM RESINS' "OMNIRAD TPO" as energy ray-activated polymerization initiators, 46.984% by mass of SIGMA-ALDRICH's "PGME" as solvent, 7.52% by mass of NANOPHASE TECHNOLOGIES CORPORATION's "AL2260" as metal oxide nanoparticles, and 0.846% by mass of Shin-Etsu Chemical Co., Ltd.'s "KY-1203" as a fluorine compound.

[0095] Here, "AL2260" contains 30% by mass of alumina particles and 70% by mass of a difunctional monomer (TPGDA). Therefore, the "weighted average of functionality" and the content ratio of resin (A) to resin (B) (hereinafter referred to as "A / B") shown in Tables 1 to 5 for Examples 1 to 13 and Comparative Examples 1 to 8 reflect the content of this difunctional monomer.

[0096] In Example 1, the weighted average functional group of resin (A) is 4.70, and the A / B ratio is 3.56.

[0097] In Example 1, the glass transition temperature Tg was 60.4°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1046.

[0098] In the folding test of Example 1, no change was observed even after folding the hard coat film 200,000 times (rating "3"). In Example 1, the water contact angle before the abrasion test was 114.7 degrees, and the water contact angle after the abrasion test was 106 degrees. No visible scratches were observed.

[0099] [Example 2] As shown in Table 1, the resin composition of Example 2 contains 7.52% by mass of "SR833S" and 22.56% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 2 are the same as those in Example 1.

[0100] In Example 2, the weighted average functional group of resin (A) is 4.55, and the A / B ratio is 4.70.

[0101] In Example 2, the glass transition temperature Tg was 54.4°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1126.

[0102] In the folding test of Example 2, no change was observed even after folding the hard coat film 200,000 times. In Example 2, the water contact angle before the abrasion test was 115.2 degrees, and the water contact angle after the abrasion test was 100.8 degrees. No visible scratches were observed.

[0103] [Example 3] As shown in Table 1, the resin composition of Example 3 contains 7.52% by mass of "SR833S" and 18.8% by mass of "DPHA" as resin (A), and 11.28% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 3 are the same as those in Example 1.

[0104] In Example 3, the weighted average functional group of resin (A) is 4.38, and the A / B ratio is 2.80.

[0105] In Example 3, the glass transition temperature Tg was 68.5°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1246.

[0106] In the folding test of Example 3, no change was observed even after folding the hard coat film 200,000 times. In Example 3, the water contact angle before the abrasion test was 113.4 degrees, and the water contact angle after the abrasion test was 105.1 degrees. No visible scratches were observed.

[0107] [Example 4] As shown in Table 1, the resin composition of Example 4 contains 9.4% by mass of "SR833S" and 20.68% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 4 are the same as those in Example 1.

[0108] In Example 4, the weighted average functional group of resin (A) is 4.34, and the A / B ratio is 4.70.

[0109] In Example 4, the glass transition temperature Tg was 68.5°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1274.

[0110] In the folding test of Example 4, no change was observed even after folding the hard coat film 200,000 times. In Example 4, the water contact angle before the abrasion test was 113.4 degrees, and the water contact angle after the abrasion test was 106.7 degrees. No visible scratches were observed.

[0111] [Example 5] As shown in Table 1, the resin composition of Example 5 contains 5.64% by mass of "SR833S" and 24.44% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 5 are the same as those in Example 1.

[0112] In Example 5, the weighted average functional group of resin (A) is 4.77, and the A / B ratio is 4.70.

[0113] In Example 5, the glass transition temperature Tg was 76.8°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1017.

[0114] In the folding test of Example 5, no change was observed even after folding the hard coat film 200,000 times. In Example 5, the water contact angle before the abrasion test was 113.4 degrees, and the water contact angle after the abrasion test was 106.5 degrees. No visible scratches were observed.

[0115] [Table 2]

[0116] [Example 6] As shown in Table 2, the resin composition of Example 6 contains 9.4% by mass of "SR833S" and 18.8% by mass of "DPHA" as resin (A), and 9.4% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 6 are the same as those in Example 1.

[0117] In Example 6, the weighted average functional group of resin (A) is 4.25, and the A / B ratio is 3.56.

[0118] In Example 6, the glass transition temperature Tg was 73.4°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1125.

[0119] Furthermore, in the folding test of Example 6, no change was observed even after folding the hard coat film 200,000 times. In Example 6, the water contact angle before the abrasion test was 113.4 degrees, and the water contact angle after the abrasion test was 107.3 degrees. No visible scratches were observed.

[0120] [Example 7] As shown in Table 2, the resin composition of Example 7 contains 5.64% by mass of "SR833S" and 20.68% by mass of "DPHA" as resin (A), and 11.28% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 7 are the same as those in Example 1.

[0121] In Example 7, the weighted average functional group of resin (A) is 4.62, and the A / B ratio is 2.80.

[0122] In Example 7, the glass transition temperature Tg was 50.6°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1152.

[0123] In the folding test of Example 7, no change was observed even after folding the hard coat film 200,000 times. In Example 7, the water contact angle before the abrasion test was 113.2 degrees, and the water contact angle after the abrasion test was 102.3 degrees. No visible scratches were observed.

[0124] [Example 8] As shown in Table 2, the resin composition of Example 8 contains 4.7% by mass of "SR833S" and 25.38% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 8 are the same as those in Example 1.

[0125] In Example 8, the weighted average functional group of resin (A) is 4.87, and the A / B ratio is 4.70.

[0126] In Example 8, the glass transition temperature Tg was 58.3°C. The loss tangent tanδ at the glass transition temperature Tg was 0.0912.

[0127] In the folding test of Example 8, no change was observed even after folding the hard coat film 200,000 times. In Example 8, the water contact angle before the abrasion test was 114.5 degrees, and the water contact angle after the abrasion test was 105.6 degrees. No visible scratches were observed.

[0128] [Example 9] As shown in Table 2, the resin composition of Example 9 contains 3.76% by mass of "SR833S" and 26.32% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 9 are the same as those in Example 1.

[0129] In Example 9, the weighted average functional group of resin (A) is 4.98, and the A / B ratio is 4.70.

[0130] In Example 9, the glass transition temperature Tg was 91.7°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1003.

[0131] In the folding test of Example 9, no change was observed even after folding the hard coat film 200,000 times. In Example 9, the water contact angle before the abrasion test was 115.8 degrees, and the water contact angle after the abrasion test was 107.1 degrees. No visible scratches were observed.

[0132] [Example 10] As shown in Table 2, the resin composition of Example 10 contains 2.82% by mass of "SR833S" and 27.26% by mass of "DPHA" as resin (A), and 7.52% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 10 are the same as those in Example 1.

[0133] In Example 10, the weighted average functional group of resin (A) is 5.09, and the A / B ratio is 4.70.

[0134] In Example 10, the glass transition temperature Tg was 85.3°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1007.

[0135] In the folding test of Example 10, no change was observed even after folding the hard coat film 200,000 times. In Example 10, the water contact angle before the abrasion test was 116.1 degrees, and the water contact angle after the abrasion test was 109.6 degrees. No visible scratches were observed.

[0136] [Table 3]

[0137] [Example 11] As shown in Table 3, the resin composition of Example 11 contains 5.64% by mass of "SR833S" and 27.26% by mass of "DPHA" as resin (A), and 4.7% by mass of "CN989" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Example 11 are the same as those in Example 1.

[0138] In Example 11, the weighted average functional group of resin (A) is 4.86, and the A / B ratio is 8.12 times.

[0139] In Example 11, the glass transition temperature Tg was 58.3°C. The loss tangent tanδ at the glass transition temperature Tg was 0.0912.

[0140] In the folding test of Example 11, no change was observed even after folding the hard coat film 200,000 times. In Example 11, the water contact angle before the abrasion test was 116.7 degrees, and the water contact angle after the abrasion test was 110.2 degrees. No visible scratches were observed.

[0141] [Example 12] As shown in Table 3, the resin composition of Example 12 contains 8.064% by mass of "SR833S" and 24.192% by mass of "DPHA" as resin (A), 8.064% by mass of SARTOMER's "CN929" as resin (B), 1.613% by mass of IGM RESINS' "OMNIRAD 184" as an energy ray-activated polymerization initiator, 49.693% by mass of "PGME" as a solvent, 8.064% by mass of "AL2260" as metal oxide nanoparticles, and 0.31% by mass of "KY-1203" as a fluorine compound.

[0142] In Example 12, the weighted average functional group of resin (A) is 4.55, and the A / B ratio is 4.70.

[0143] In Example 12, the glass transition temperature Tg was 69.4°C. The loss tangent tanδ at the glass transition temperature Tg was 0.09.

[0144] In the folding test of Example 12, the hard coat film showed no change even after being folded more than 250,000 times. In Example 12, the water contact angle before the abrasion test was 115.3 degrees, and the water contact angle after the abrasion test was 107.7 degrees. No visible scratches were observed.

[0145] [Example 13] As shown in Table 3, the resin composition of Example 13 contains 8.014% by mass of "SR833S" and 22.04% by mass of "DPHA" as resin (A), 10.02% by mass of "CN989" as resin (B), 1.603% by mass of "OMNIRAD 184" as an energy ray-activated polymerization initiator, 50% by mass of "PGME" as a solvent, 8.014% by mass of "AL2260" as metal oxide nanoparticles, and 0.31% by mass of "KY-1203" as a fluorine compound.

[0146] In Example 13, the weighted average functional group of resin (A) is 4.47, and the A / B ratio is 3.56.

[0147] In Example 13, the glass transition temperature Tg was 80°C. The loss tangent tanδ at the glass transition temperature Tg was 0.099.

[0148] In the folding test of Example 13, the hard coat film showed no change even after being folded more than 250,000 times. In Example 13, the water contact angle before the abrasion test was 114.9 degrees, and the water contact angle after the abrasion test was 105.9 degrees. No visible scratches were observed.

[0149] As explained above, in Examples 1 to 13, the weighted average functional group count of resin (A) was 4 or more. Therefore, the glass transition temperature Tg of Examples 1 to 13 was in the range of 50°C to 100°C, and the loss tangent tanδ at the glass transition temperature Tg was in the range of 0.07 to 0.15. For this reason, it is estimated that the number of folds in Examples 1 to 13 was 200,000 or more. Furthermore, it is estimated that the water contact angle before the abrasion test of Examples 1 to 13 was greater than 110 degrees, and the water contact angle after the abrasion test was greater than 100 degrees. In addition, it is estimated that in Examples 1 to 13, the decrease in the water contact angle after the abrasion test compared to the water contact angle before the abrasion test was less than 13%. Furthermore, it is estimated that no visible scratches were observed in Examples 1 to 13. In other words, it was confirmed that Examples 1 to 13 have the performance to withstand repeated folding over a large number of times, and that it is possible to improve scratch resistance and abrasion resistance even in high-temperature environments such as inside vehicles.

[0150] [Table 4]

[0151] [Comparative Example 1] As shown in Table 4, the resin composition of Comparative Example 1 contains 7.515% by mass of "SR833S", 5.01% by mass of SARTOMER's "SR306 (TPGDA)", and 9.018% by mass of "DPHA" as resin (A), 16.032% by mass of "CN929" as resin (B), 2.004% by mass of "OMNIRAD 184" as an energy ray-activated polymerization initiator, 50.09% by mass of "PGME" as a solvent, 10.02% by mass of "AL2460" from NANOPHASE TECHNOLOGIES CORPORATION as metal oxide nanoparticles, and 0.31% by mass of "KY-1203" as a fluorine compound.

[0152] In Comparative Example 1, the weighted average functional group of resin (A) is 2.77, and the A / B ratio is 1.78.

[0153] In Comparative Example 1, the glass transition temperature Tg was 59.5°C. The loss tangent tanδ at the glass transition temperature Tg was 0.1516.

[0154] In the folding test of Comparative Example 1, no change was observed even after folding the film more than 250,000 times. The water contact angle before the abrasion test was 115 degrees, and the water contact angle after the abrasion test was 106 degrees. On the other hand, visible scratches were observed.

[0155] As described above, in Comparative Example 1, the weighted average functional group of resin (A) contained in the resin composition is 2.77. Therefore, the loss tangent tanδ at the glass transition temperature Tg of Comparative Example 1 is high at 0.1516, and the flexibility of the film is slightly reduced. For this reason, it is presumed that visible scratches were observed in Comparative Example 1.

[0156] [Comparative Example 2] As shown in Table 4, the resin composition of Comparative Example 2 contains 16.65% by mass of SARTOMER's "SR444" as resin (A), 30.91% by mass of MIWON SPECIALTY CHEMICAL's "PU610" as resin (B), 2.37% by mass of "OMNIRAD 184" as an energy ray-activated polymerization initiator, 49.76% by mass of "PGME" as a solvent, and 0.31% by mass of "KY-1203" as a fluorine compound. The resin composition of Comparative Example 2 does not contain metal oxide nanoparticles. Furthermore, "SR444" is a monomer that mainly consists of a trifunctional group and also contains a tetrafunctional group.

[0157] In Comparative Example 2, the weighted average functional group of resin (A) is 3.00, and the A / B ratio is 0.54.

[0158] In Comparative Example 2, the glass transition temperature Tg was 100°C. The loss tangent tanδ at the glass transition temperature Tg was 0.055.

[0159] In the folding test of Comparative Example 2, cracks appeared in the sample during the process of folding the film 100 times. In Comparative Example 2, the water contact angle before the abrasion test was 110 degrees, and the water contact angle after the abrasion test was 95 degrees. No visible scratches were observed.

[0160] As described above, in Comparative Example 2, the weighted average functional group of resin (A) contained in the resin composition is 3.00. Therefore, the loss tangent tanδ at the glass transition temperature Tg of Comparative Example 2 is low at 0.055, and the hardness of the film is too high. For this reason, it is presumed that the number of folds for Comparative Example 2 was 100 or less. Overall, in Comparative Example 2, the scratch resistance was improved by increasing the crosslinking density, and no scratches were observed. On the other hand, it is thought that the flexibility was poor because the crosslinking density was increased too much, and good results were not obtained in the folding test.

[0161] [Comparative Example 3] As shown in Table 4, the resin composition of Comparative Example 3 contains 7.35% by mass of "SR444" and 24.51% by mass of SARTOMER's "IBOA(SR506-A)" as resin (A), 9.81% by mass of SARTOMER's "CN9047" as resin (B), 0.98% by mass of "OMNIRAD 184" as an energy ray-activated polymerization initiator, 49.75% by mass of "PGME" as a solvent, 7.35% by mass of "AL2260" as metal oxide nanoparticles, and 0.25% by mass of "KY-1203" as a fluorine compound. Here, "IBOA(SR506-A)" is a monofunctional monomer.

[0162] In Comparative Example 3, the weighted average functional group of resin (A) is 1.54, and the A / B ratio is 3.77.

[0163] In Comparative Example 3, the glass transition temperature Tg was 129.6°C. The loss tangent tanδ at the glass transition temperature Tg was 0.25.

[0164] In the folding test of Comparative Example 3, no change was observed even after folding the film 200,000 times. However, in Comparative Example 3, the water contact angle before the abrasion test was 113.4 degrees, and the water contact angle after the abrasion test was 87.3 degrees. Visually observable scratches were confirmed.

[0165] As described above, in Comparative Example 3, the weighted average functional group of resin (A) contained in the resin composition is 1.54. Therefore, the glass transition temperature Tg of Comparative Example 3 was high at 129.6°C. The loss tangent tanδ at the glass transition temperature Tg of Comparative Example 3 was high at 0.25. In other words, because Comparative Example 3 has a high tanδ, the crosslinking density is low and it has flexibility, so it showed good results in the folding test, but on the other hand, the hardness was too low, so it is presumed that visible scratches were observed after the abrasion test.

[0166] [Comparative Example 4] As shown in Table 4, the resin composition of Comparative Example 4 contains 7.35% by mass of "SR444" and 22.06% by mass of "IBOA (SR506-A)" as resin (A), and 12.26% by mass of "CN9047" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Comparative Example 4 are the same as those in Comparative Example 3.

[0167] In Comparative Example 4, the weighted average functional group of resin (A) is 1.57, and the A / B ratio is 2.82 times.

[0168] In Comparative Example 4, the glass transition temperature Tg was 117.8°C. The loss tangent tanδ at the glass transition temperature Tg was 0.208.

[0169] In the folding test of Comparative Example 4, no change was observed even after folding the film 200,000 times. However, in Comparative Example 4, the water contact angle before the abrasion test was 113.7 degrees, and the water contact angle after the abrasion test was 73.9 degrees. Visually observable scratches were confirmed.

[0170] As described above, in Comparative Example 4, the weighted average functional group of resin (A) contained in the resin composition is 1.57. Therefore, the glass transition temperature Tg of Comparative Example 4 was high at 117.8°C. The loss tangent tanδ at the glass transition temperature Tg of Comparative Example 4 was high at 0.208. In other words, because Comparative Example 4 has a high tanδ, the crosslinking density is low and it has flexibility, so it showed good results in the folding test, but on the other hand, the hardness was too low, so it is presumed that visible scratches were observed after the abrasion test.

[0171] [Comparative Example 5] As shown in Table 4, the resin composition of Comparative Example 5 contains 7.35% by mass of "SR444" and 19.61% by mass of "IBOA (SR506-A)" as resin (A), and 14.71% by mass of "CN9047" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Comparative Example 5 are the same as those in Comparative Example 3.

[0172] In Comparative Example 5, the weighted average functional group of resin (A) is 1.62, and the A / B ratio is 2.18 times.

[0173] In Comparative Example 5, the glass transition temperature Tg was 106.3°C. The loss tangent tanδ at the glass transition temperature Tg was 0.194.

[0174] In the folding test of Comparative Example 5, no change was observed even after folding the film 200,000 times. However, in Comparative Example 5, the water contact angle before the abrasion test was 114.1 degrees, and the water contact angle after the abrasion test was 76.1 degrees. Visually observable scratches were confirmed.

[0175] As described above, in Comparative Example 5, the weighted average functional group of resin (A) contained in the resin composition is 1.62. Therefore, the glass transition temperature Tg of Comparative Example 5 was high at 106.3°C. The loss tangent tanδ at the glass transition temperature Tg of Comparative Example 5 was high at 0.194. In other words, because Comparative Example 5 has a high tanδ, the crosslinking density is low and it has flexibility, so it showed good results in the folding test, but on the other hand, the hardness was too low, so it is presumed that visible scratches were observed after the abrasion test.

[0176] [Table 5]

[0177] [Comparative Example 6] As shown in Table 5, the resin composition of Comparative Example 6 contains 4.9% by mass of "SR444" and 24.51% by mass of "IBOA (SR506-A)" as resin (A), and 12.26% by mass of "CN9047" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Comparative Example 6 are the same as those in Comparative Example 3.

[0178] In Comparative Example 6, the weighted average functional group of resin (A) was 1.43, and the A / B ratio was 2.82 times.

[0179] In Comparative Example 6, the glass transition temperature Tg was 111.9°C. The loss tangent tanδ at the glass transition temperature Tg was 0.2791.

[0180] In the folding test of Comparative Example 6, no change was observed even after folding the film 200,000 times. However, in Comparative Example 6, the water contact angle before the abrasion test was 113.5 degrees, and the water contact angle after the abrasion test was 77.4 degrees. Visually observable scratches were confirmed.

[0181] As described above, in Comparative Example 6, the weighted average functional group of resin (A) contained in the resin composition is 1.43. Therefore, the glass transition temperature Tg of Comparative Example 6 was high at 111.9°C. The loss tangent tanδ at the glass transition temperature Tg of Comparative Example 6 was high at 0.2791. In other words, because Comparative Example 6 has a high tanδ, the crosslinking density is low and it has flexibility, so it showed good results in the folding test, but on the other hand, the hardness was too low, so it is presumed that visible scratches were observed after the abrasion test.

[0182] [Comparative Example 7] As shown in Table 5, the resin composition of Comparative Example 7 contains 4.9% by mass of "SR444" and 22.06% by mass of "IBOA (SR506-A)" as resin (A), and 14.71% by mass of "CN9047" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Comparative Example 7 are the same as those in Comparative Example 3.

[0183] In Comparative Example 7, the weighted average functional group of resin (A) was 1.47, and the A / B ratio was 2.18 times.

[0184] In Comparative Example 7, the glass transition temperature Tg was 102.7°C. The loss tangent tanδ at the glass transition temperature Tg was 0.2455.

[0185] In the folding test of Comparative Example 7, no change was observed even after folding the film 200,000 times. However, in Comparative Example 7, the water contact angle before the abrasion test was 113.5 degrees, and the water contact angle after the abrasion test was 70.3 degrees. Visually observable scratches were confirmed.

[0186] As described above, in Comparative Example 7, the weighted average functional group of resin (A) contained in the resin composition is 1.47. Therefore, the glass transition temperature Tg of Comparative Example 7 was high at 102.7°C. In addition, the loss tangent tanδ at the glass transition temperature Tg of Comparative Example 7 was high at 0.2455. That is, because Comparative Example 7 has a high tanδ, the crosslinking density is low and it has flexibility, so it showed good results in the folding test, but on the other hand, the hardness was too low, so it is presumed that visible scratches were observed after the abrasion test.

[0187] [Comparative Example 8] As shown in Table 5, the resin composition of Comparative Example 8 contains 4.9% by mass of "SR444" and 19.61% by mass of "IBOA (SR506-A)" as resin (A), and 17.16% by mass of "CN9047" as resin (B). The energy ray-activated polymerization initiator, solvent, metal oxide nanoparticles, and fluorine compound contained in the resin composition of Comparative Example 8 are the same as those in Comparative Example 3.

[0188] In Comparative Example 8, the weighted average functional group of resin (A) is 1.50, and the A / B ratio is 1.73.

[0189] In Comparative Example 8, the glass transition temperature Tg was 93.2°C. The loss tangent tanδ at the glass transition temperature Tg was 0.2183.

[0190] In the folding test of Comparative Example 8, no change was observed even after folding the film 200,000 times. However, in Comparative Example 8, the water contact angle before the abrasion test was 107 degrees, and the water contact angle after the abrasion test was 65 degrees. Visually observable scratches were confirmed.

[0191] As described above, in Comparative Example 8, the weighted average functional group of resin (A) in the resin composition is 1.50. Therefore, the loss tangent tanδ at the glass transition temperature Tg of Comparative Example 8 is high at 0.2183, resulting in excessively low hardness. Consequently, the water contact angle after the abrasion test of Comparative Example 8 was low at 65 degrees, and it is presumed that visible scratches were observed.

[0192] As described above, this embodiment makes it possible to provide a hard coat film 10 that can withstand repeated folding many times, and that also has scratch resistance and abrasion resistance.

[0193] Embodiments of the present invention have been described above with reference to the attached drawings. However, the invention disclosed herein is not limited thereto, and it will be clear to those skilled in the art that various changes and modifications are possible within the scope of this disclosure and claims.

[0194] The hard coat film 10 of the present invention can be used as a protective film in any device that requires a protective film, such as display screens, screens, goggles, eye shields, and face shields. It is particularly suitable for flexible displays, electronic devices such as information terminals, and all other similar articles that are used in a folded (foldable) manner.

[0195] When the hard coat film 10 of the present invention is used in a display device, the hard coat film 10 may include a functional material layer and / or an adhesive layer to improve visibility. Examples of functional material layers include a diffusion layer and an anti-reflective layer. Examples of adhesive layers include an optically elastic resin layer. [Explanation of Symbols]

[0196] 10 Hard coat film 11 Base material 12 Hard coating layer 12a 1st area 12b Second area 13. Anti-fouling layer 100 Film manufacturing equipment 110 Feed Roll 112 Reel Roll 114a~d Guide Roll 120 Coating device 130 Drying equipment 140 Curing equipment 144 Guide Roll 146 Guide Roll 148 Light source

Claims

1. Substrate and A hard coating layer laminated on the substrate, comprising a cured product of a resin composition containing resin (A) and resin (B), Equipped with, The resin (A) is a polyfunctional (meth)acrylic monomer having four or more weighted average functional groups. The aforementioned resin (B) is an aliphatic urethane acrylate, The content of the resin (A) in the resin composition is 20% by mass or more and 40% by mass or less. The content of the resin (B) in the resin composition is 2% by mass or more and 15% by mass or less. The resin composition further comprises metal oxide nanoparticles having an average particle size of 100 nm or less, and a fluorine compound. The glass transition temperature Tg of the hard coating layer is 50°C or higher and 100°C or lower. A hard coat film in which, when the loss tangent tanδ of the hard coating layer is measured by dynamic viscoelasticity measurement with a dynamic load applied at a frequency of 1 Hz, the loss tangent tanδ at the glass transition temperature Tg is 0.07 or more and 0.15 or less.

2. The hard coat film according to claim 1, wherein the content of the metal oxide nanoparticles in the resin composition is 2% by mass or more and 5% by mass or less with respect to the total solid content of the resin composition of the hard coating layer.

3. The hard coat film according to claim 1 or 2, wherein the metal oxide constituting the metal oxide nanoparticles is either silica or alumina, or both.

4. The hard coat film according to claim 1 or 2, wherein the metal oxide nanoparticles have a Mohs hardness greater than 6.

5. The hard coat film according to claim 1 or 2, wherein when the steel wool is abraded against the surface of the hard coating layer using an abrasion tester with steel wool #0000 under the conditions of load: 1000 g, speed: 50 mm / sec, reciprocating distance: 40 mm, and number of reciprocations: 2500 times, the water contact angle of the surface of the hard coating layer after abrasion is greater than 100 degrees.

6. The hard coat film according to claim 5, wherein the water contact angle of the surface of the hard coating layer before wear is greater than 110 degrees.

7. The hard coat film according to claim 6, wherein the rate of decrease in the water contact angle after wear relative to the water contact angle before wear of the surface of the hard coating layer is less than 13%.

8. The hard coat film according to claim 1 or 2, wherein the content of resin (A) in the resin composition is greater than twice and less than nine times the content of resin (B).

9. The hard coat film according to claim 1 or 2, wherein the substrate is a thermoplastic substrate having a thickness of 10 μm or more and 200 μm or less.

10. The hard coat film according to claim 1 or 2, wherein the fluorine compound contained in the resin composition is segregated on the surface side of the hard coating layer.

11. The hard coat film according to claim 10, wherein the segregated fluorine compound has an antifouling function.

12. The hard coat film according to claim 1 or 2, wherein the fluorine compound contained in the resin composition is not segregated on the substrate side of the hard coating layer.

13. The hard coat film according to claim 1 or 2, wherein the hard coat film is configured to be folded at least 100,000 times by bending in or out without causing at least one of cracking, delamination, and loss of optical properties.

14. The hard coat film according to claim 13, wherein the optical properties are one or more selected from the group consisting of total light transmittance (%), transmittance haze, glossiness, and chromaticity b* (intensity of color from blue to yellow).

Images