Method for producing processed film

Abstract

To provide a method for producing a processed film in which curl amount is reduced.SOLUTION: A method for producing a processed film is provided, the processed film including a thermoplastic resin film and a hard coat layer disposed in contact with a main surface of the thermoplastic resin film, the method comprising a step (1) of preparing a laminated film that includes the thermoplastic resin film and an uncured layer containing a UV-curable resin disposed in contact with the main surface of the thermoplastic resin film, and a step (2) of irradiating the laminated film with ultraviolet light to produce the processed film. The step (2) comprises following stages in which: the temperature of the thermoplastic resin film increases so that the thermoplastic resin film softens, the uncured layer subjected to ultraviolet irradiation cures while simultaneously exhibiting curing shrinkage, and, following the curing shrinkage of the uncured layer in the in-plane direction, the softened thermoplastic resin film undergoes shrinkage in the in-plane direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a processed film. [Background technology]

[0002] In recent years, display devices, lighting devices, and solar cells have become thinner and lighter in terms of portability, storage, design, etc. Furthermore, the film-like materials used in these devices are being continuously produced using a roll-to-roll process.

[0003] In order to reduce scratches on the surface of these devices, a film-like member having a hard coat layer may be used. A film-like member having a hard coat layer is produced, for example, by applying a liquid composition for forming a hard coat layer to a substrate film to form a layer of the liquid composition, and then curing the liquid composition (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-157068 Summary of the Invention [Problem to be solved by the invention]

[0005] A film having a hard coat layer may be very fragile and have poor handleability, and therefore, in order to improve the handleability, it may be possible to perform processing such as further laminating a resin film to the film having a hard coat layer to reinforce the film having a hard coat layer. However, if a film having a hard coat layer has a strong curl, it may be difficult to process the film by a roll-to-roll process. For example, when a strongly curled film is set in a processing device, or when the film is wound up after processing, the film may be damaged. In such a case, it is not easy to improve the productivity of the film.

[0006] The present invention has been made in view of the above, and has an object to provide a method for producing a processed film containing a hard coat layer with a small amount of curl. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, the present invention provides the following.

[0008] <1> A method for producing a processed film comprising a thermoplastic resin film and a hard coat layer provided in contact with a main surface of the thermoplastic resin film; A step (1) of preparing a laminated film including the thermoplastic resin film and a pre-curing layer including an ultraviolet-curable resin provided in contact with a main surface of the thermoplastic resin film; and a step (2) of irradiating the laminated film with ultraviolet light to obtain the processed film; The step (2) the temperature of the thermoplastic resin film is increased to soften the thermoplastic resin film; The pre-curing layer irradiated with ultraviolet light undergoes curing and shrinkage at the same time; and A method for producing a processed film, comprising shrinking the softened thermoplastic resin film in an in-plane direction in response to cure shrinkage of the pre-curing layer in the in-plane direction. <2> The ultraviolet irradiation to the laminated film in the step (2) is 300 mJ / cm 2 More than 660mJ / cm 2 The following cumulative light intensity is used: <1> A method for producing the processed film described in claim 1. <3> The thermoplastic resin film contains an ultraviolet absorber. <2> A method for producing the processed film described in claim 1. <4> The thermoplastic resin film contains an ultraviolet absorber in an amount of 4% by weight or more and 7% by weight or less. <1> ~ <3> 10. The method for producing the processed film according to claim 9 . <5> The absorbance of the ultraviolet absorber is 0.2 or more in at least a part of the measurement wavelength range of 330 nm or more and 400 nm or less. <3> or <4> A method for producing the processed film described in claim 1. <6> The thermoplastic resin film contains a polymer containing an alicyclic structure. <1> ~ <5> 10. The method for producing the processed film according to claim 9 . <7> The pre-cured layer contains fine particles. <1> ~ <6> 10. The method for producing the processed film according to claim 9 . <8> The thickness of the thermoplastic resin film is 15 μm or more and 100 μm or less. <1> ~ <7> 10. The method for producing the processed film according to claim 9 . <9> The thickness of the hard coat layer is 1.0 μm or more and 10.0 μm or less. <1> ~ <8> 10. The method for producing the processed film according to claim 9 . <10> In the step (2), the temperature of the thermoplastic resin film is set to Tg2-50°C or higher (where Tg2 represents the glass transition temperature of the thermoplastic resin film). <1> ~ <9> 10. The method for producing the processed film according to claim 9 . [Effects of the Invention]

[0009] According to the present invention, a method for producing a processed film containing a hard coat layer and having a small amount of curl can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a laminated film. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the laminated film. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented as desired without departing from the scope of the claims of the present invention and their equivalents. The components of the embodiments shown below can be combined as appropriate. In addition, in the drawings, the same components are designated by the same reference numerals, and their description may be omitted.

[0012] In the following description, a "long" film refers to a film having a length that is 5 times or more its width, preferably 10 times or more its width, and specifically refers to a film having a length that can be wound into a roll for storage or transportation. There is no particular upper limit to the length of the film, and it can be, for example, 100,000 times or less its width.

[0013] In the following description, unless otherwise specified, the term "plate" is not limited to a rigid member, but also includes a flexible member such as a resin film.

[0014] In the following description, the term "(meth)acrylic" encompasses "acrylic", "methacrylic", and combinations thereof. In the following description, the term "(meth)acrylate" encompasses "acrylate," "methacrylate," and combinations thereof.

[0015] In the following description, unless otherwise specified, the term "adhesive" refers not only to adhesives in the narrow sense (adhesives having a shear storage modulus of 1 MPa to 500 MPa at 23°C after irradiation with energy rays or after heat treatment), but also to pressure-sensitive adhesives having a shear storage modulus of less than 1 MPa at 23°C. Therefore, the term "adhesive layer" encompasses not only a layer of an adhesive in the narrow sense, but also a layer of a pressure-sensitive adhesive.

[0016] In the following description, ultraviolet light means light with a wavelength of 400 nm or less.

[0017] <1. Overview of the manufacturing method for processed film> A method for producing a processed film according to one embodiment of the present invention includes: A method for producing a processed film comprising a thermoplastic resin film and a hard coat layer provided in contact with a main surface of the thermoplastic resin film; A step (1) of preparing a laminated film including the thermoplastic resin film and a pre-curing layer including an ultraviolet-curable resin provided in contact with a main surface of the thermoplastic resin film; and a step (2) of irradiating the laminated film with ultraviolet light to obtain the processed film; The step (2) the temperature of the thermoplastic resin film is increased to soften the thermoplastic resin film; The pre-curing layer irradiated with ultraviolet light undergoes curing and shrinkage at the same time; and The softened thermoplastic resin film shrinks in the in-plane direction in response to the cure shrinkage of the pre-curing layer in the in-plane direction.

[0018] According to the process for producing a processed film according to this embodiment, a processed film including a hard coat layer and having a small amount of curl can be produced.

[0019] The reason why the processed film manufacturing method according to this embodiment can produce a processed film with a small amount of curl is presumed to be as follows, but the technical scope of the present invention is not limited by the following reasons. Curling of a film can occur, for example, when stresses in the in-plane direction are not balanced between one main surface side and the other main surface side of the film, resulting in a large difference in stress. In step (2), when the laminate film including the pre-curing layer is irradiated with ultraviolet light, the pre-curing layer irradiated with ultraviolet light undergoes cure shrinkage at least in the in-plane direction as it cures. Meanwhile, the thermoplastic resin film is formed from a thermoplastic resin that can be plastically deformed by heat, and the pre-curing layer is provided in contact with the main surface of the thermoplastic resin film. In step (2), when the pre-curing layer cures and undergoes cure shrinkage in the in-plane direction of the pre-curing layer, the thermoplastic resin film is in contact with the pre-curing layer, and therefore stress is generated in the thermoplastic resin film due to the external force of the pre-curing layer that attempts to shrink the thermoplastic resin film in the in-plane direction. However, in step (2), when the temperature of the thermoplastic resin film rises and the thermoplastic resin film softens, the thermoplastic resin film shrinks in the in-plane direction, releasing the stress, thereby reducing the stress in the thermoplastic resin film. On the other hand, the pre-curing layer is provided in contact with the main surface of the thermoplastic resin film, but the thermoplastic resin film softens and shrinks in response to the cure shrinkage of the pre-curing layer in the in-plane direction. Therefore, the cure shrinkage of the pre-curing layer is not hindered by the thermoplastic resin film, and in the hard coat layer formed by curing the pre-curing layer, the stress in the direction of shrinkage in the in-plane direction is reduced. In this way, the thermoplastic resin film shrinks in the in-plane direction as the pre-curing layer cures and shrinks, resulting in a decrease in the in-plane stress between the thermoplastic resin film side and the hard coat layer side of the processed film, reducing the difference in stress, and it is presumed that this results in a processed film with little curl.

[0020] <2. Process (1)> Step (1) will be described in more detail below. In step (1), a laminated film is prepared, which includes a thermoplastic resin film and a pre-curing layer containing an ultraviolet-curable resin provided in contact with a main surface of the thermoplastic resin film.

[0021] (Structure of laminated film) Fig. 1 is a cross-sectional view schematically showing an example of a laminated film, in which the thermoplastic resin film included in the laminated film has a single-layer structure. As shown in FIG. 1, a long laminated film 100 includes a thermoplastic resin film 110 and a pre-curing layer 120 provided directly on a main surface 110U of the thermoplastic resin film. The thermoplastic resin film 110 has a single layer structure and is made of a thermoplastic resin, which will be described later, and is usually made of only a thermoplastic resin.

[0022] Fig. 2 is a cross-sectional view schematically showing another example of a laminated film, in which the thermoplastic resin film included in the laminated film has a multi-layer structure. As shown in FIG. 2, the long laminated film 200 includes a thermoplastic resin film 210 and a pre-curing layer 120 provided directly on a main surface 210U of the thermoplastic resin film 210. The thermoplastic resin film 210 includes an intermediate layer 211, a surface layer 212 provided directly on one main surface 211U of the intermediate layer 211, and a surface layer 213 provided directly on the other main surface 211D of the intermediate layer 211. The main surface 210U of the thermoplastic resin film 210 is also the main surface of the surface layer 212. Therefore, the laminated film 200 includes the pre-curing layer 120, the surface layer 212, the intermediate layer 211, and the surface layer 213 in this order.

[0023] The surface layer 212, the intermediate layer 211, and the surface layer 213 are all formed from a thermoplastic resin, which will be described later, and usually consist of only a thermoplastic resin. The composition of the thermoplastic resin forming the surface layer 212 and the composition of the thermoplastic resin forming the surface layer 213 may be different from each other, but from the viewpoints of reducing the manufacturing cost of the processed film and suppressing curling, it is preferable that they are the same.

[0024] Furthermore, the thickness of the surface layer 212 and the thickness of the surface layer 213 may be different from each other, but from the viewpoint of suppressing curling, it is preferable that they are the same.

[0025] When the thermoplastic resin film has a multilayer structure, it may contain any layer in combination with the surface layer 212, intermediate layer 211, and surface layer 213. For example, any resin layer may be provided between the intermediate layer and the surface layer. However, from the viewpoint of making the thermoplastic resin film thin, when the thermoplastic resin film has a multilayer structure, it is preferable that the thermoplastic resin film be a three-layer film having only a first surface layer, an intermediate layer, and a second surface layer in this order, and therefore it is preferable that the intermediate layer and the surface layer are in direct contact with each other.

[0026] The main surface of the thermoplastic resin film and the pre-curing layer may be in contact with each other via an optional layer such as an adhesive layer, but it is preferable that they are in direct contact with each other without any optional layer therebetween.

[0027] The pre-curing layer may be provided on both of the two main surfaces of the thermoplastic resin film, but it is preferred that the pre-curing layer be provided on only one of the main surfaces of the thermoplastic resin film. Processed films manufactured by conventional methods in which a hard coat layer is provided on only one main surface of a thermoplastic resin film tend to curl more than processed films in which hard coat layers are provided on both main surfaces. According to the manufacturing method of this embodiment, even processed films in which a hard coat layer is provided on only one main surface of a thermoplastic resin film can have a sufficiently small curl. By providing a pre-curing layer on only one main surface of the thermoplastic resin film, this effect can be fully utilized.

[0028] (thermoplastic resin film) A thermoplastic resin film is a film formed from a thermoplastic resin, and is usually made solely of a thermoplastic resin. Because a thermoplastic resin film is formed from a thermoplastic resin, it can undergo plastic deformation when heated. Therefore, if the temperature of the thermoplastic resin film rises when a pre-curing layer provided on the thermoplastic resin film cures and shrinks, the thermoplastic resin film can deform and shrink in accordance with the cure shrinkage of the pre-curing layer.

[0029] The thermoplastic resin generally contains a thermoplastic polymer and optional components as needed. The thermoplastic polymer may be used alone or in combination of two or more types in any ratio.

[0030] Examples of thermoplastic polymers that can be contained in the thermoplastic resin include polymers containing an alicyclic structure (for example, norbornene-based polymers), and polymers containing an alicyclic structure are preferred.

[0031] When the thermoplastic resin film has a multilayer structure, the thermoplastic resins forming each layer preferably contain a polymer containing an alicyclic structure, and more preferably contain the same polymer containing an alicyclic structure, which makes it easier to increase the adhesive strength between the layers and to suppress light reflection at the interface between the layers.

[0032] The polymer containing an alicyclic structure is a polymer whose structural unit contains an alicyclic structure. The polymer containing an alicyclic structure usually has excellent moist heat resistance. Therefore, by using the polymer containing an alicyclic structure, the moist heat resistance of the processed film can be improved.

[0033] The polymer containing an alicyclic structure may have the alicyclic structure in the main chain or in the side chain, and among them, from the viewpoints of mechanical strength and heat resistance, the polymer containing an alicyclic structure in the main chain is preferred.

[0034] Examples of the alicyclic structure include saturated alicyclic hydrocarbon (cycloalkane) structures, unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures, etc. Among these, from the viewpoints of mechanical strength and heat resistance, cycloalkane structures and cycloalkene structures are preferred, and cycloalkane structures are particularly preferred.

[0035] The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, and preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less, per alicyclic structure. By setting the number of carbon atoms constituting the alicyclic structure within this range, the mechanical strength, heat resistance, and moldability of the resin containing the polymer containing the alicyclic structure are well balanced.

[0036] In the polymer containing an alicyclic structure, the proportion of the structural unit having an alicyclic structure can be appropriately selected depending on the purpose of use of the processed film. The proportion of the structural unit having an alicyclic structure in the polymer containing an alicyclic structure is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and is usually 100% by weight or less. When the proportion of the structural unit having an alicyclic structure in the polymer containing an alicyclic structure is within this range, the transparency and heat resistance of the resin containing the polymer containing an alicyclic structure are good.

[0037] Examples of polymers containing an alicyclic structure include cycloolefin polymers (e.g., norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, and hydrogenated products thereof), vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof. Cycloolefin polymers refer to polymers having a structure obtained by polymerizing cycloolefins (which may be monocyclic or polycyclic and may have a substituent), and hydrogenated products thereof. The cycloolefin polymers are not limited by their polymerization method. Among these, norbornene polymers are more preferred because of their excellent transparency and moldability.

[0038] Examples of norbornene-based polymers include ring-opening polymers of monomers having a norbornene structure and hydrogenated products thereof; and addition polymers of monomers having a norbornene structure and hydrogenated products thereof. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, ring-opening copolymers of two or more types of monomers having a norbornene structure, and ring-opening copolymers of a monomer having a norbornene structure and any monomer copolymerizable therewith. Examples of addition polymers of monomers having a norbornene structure include addition homopolymers of one type of monomer having a norbornene structure, addition copolymers of two or more types of monomers having a norbornene structure, and addition copolymers of a monomer having a norbornene structure and any monomer copolymerizable therewith. Among these, hydrogenated products of ring-opening polymers of monomers having a norbornene structure are particularly suitable from the viewpoints of moldability, heat resistance, low moisture absorption, dimensional stability, light weight, etc.

[0039] Examples of monomers having a norbornene structure include bicyclo[2.2.1]hept-2-ene (common name: norbornene), tricyclo[4.3.0.1 2,5 ]Deca-3,7-diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 2,5 ]dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodec-3-ene (trivial name: tetracyclododecene) and derivatives of these compounds (for example, those having a substituent on the ring). Examples of the substituent include an alkyl group, an alkylene group, and a polar group. These substituents may be the same or different, and a plurality of them may be bonded to the ring. The monomer having a norbornene structure may be used alone or in combination of two or more kinds in any ratio.

[0040] Examples of the polar group include a heteroatom or an atomic group having a heteroatom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfonic acid group.

[0041] Examples of monomers capable of ring-opening copolymerization with a monomer having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene, and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene, and derivatives thereof; etc. One type of monomer capable of ring-opening copolymerization with a monomer having a norbornene structure may be used alone, or two or more types may be used in combination at any ratio.

[0042] A ring-opening polymer of a monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of a ring-opening polymerization catalyst.

[0043] Examples of monomers that can be addition-copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene, and derivatives thereof; cycloolefins, such as cyclobutene, cyclopentene, and cyclohexene, and derivatives thereof; and non-conjugated dienes, such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 5-methyl-1,4-hexadiene. Among these, α-olefins are preferred, and ethylene is more preferred. Furthermore, the monomers that can be addition-copolymerized with a monomer having a norbornene structure may be used alone, or two or more may be used in combination at any ratio.

[0044] An addition polymer of a monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of an addition polymerization catalyst.

[0045] The hydrogenated products of the ring-opening polymer and addition polymer described above can be produced, for example, by hydrogenating the carbon-carbon unsaturated bonds, preferably to 90% or more, in a solution of the ring-opening polymer and addition polymer in the presence of a hydrogenation catalyst containing a transition metal such as nickel or palladium.

[0046] Among norbornene-based polymers, the structural units are X: bicyclo[3.3.0]octane-2,4-diyl-ethylene structure and Y: tricyclo[4.3.0.1 2,5 ]decane-7,9-diyl-ethylene structure, the amount of these structural units being 90% by weight or more of the total structural units of the norbornene-based polymer, and the ratio of X to Y being 100:0 to 40:60 by weight. By using such a polymer, the layer containing the norbornene-based polymer can be made to have no dimensional change over the long term and excellent stability of optical properties.

[0047] The weight-average molecular weight (Mw) of the polymer containing an alicyclic structure is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 80,000 or less, particularly preferably 50,000 or less. When the weight-average molecular weight is within this range, the mechanical strength and moldability of the layer containing the polymer containing an alicyclic structure are well balanced.

[0048] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polymer containing an alicyclic structure is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3.5 or less, more preferably 3.0 or less, particularly preferably 2.7 or less. By making the molecular weight distribution equal to or greater than the lower limit of the above range, the productivity of the polymer can be increased and production costs can be reduced. Furthermore, by making it equal to or less than the upper limit, the amount of low-molecular-weight components is reduced, thereby suppressing relaxation during exposure to high temperatures and improving the stability of the layer containing the polymer containing an alicyclic structure.

[0049] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) can be measured as polyisoprene or polystyrene equivalent weight-average molecular weight by gel permeation chromatography using cyclohexane as a solvent. However, if the sample is insoluble in cyclohexane, toluene may be used as the solvent.

[0050] The glass transition temperature of the polymer containing an alicyclic structure is preferably 100° C. or higher, more preferably 110° C. or higher, and particularly preferably 120° C. or higher, and is preferably 160° C. or lower, more preferably 150° C. or lower, and particularly preferably 140° C. or lower. By setting the glass transition temperature of the polymer containing an alicyclic structure to be equal to or higher than the lower limit of the above range, the durability of the film containing the polymer containing an alicyclic structure in a high-temperature environment can be increased, and by setting the glass transition temperature to be equal to or lower than the upper limit of the above range, the film containing the polymer containing an alicyclic structure can be easily stretched.

[0051] The refractive index of the polymer containing an alicyclic structure is preferably 1.45 or more, more preferably 1.48 or more, particularly preferably 1.50 or more, and is preferably 1.60 or less, more preferably 1.58 or less, particularly preferably 1.54 or less. By setting the refractive index of the polymer containing an alicyclic structure within the above range, it becomes easy to reduce the difference in refractive index between the processed film and the polarizer, and the transmittance of the polarizing plate including the processed film can be increased.

[0052] The saturated water absorption of the polymer containing an alicyclic structure is preferably 0.03 wt% or less, more preferably 0.02 wt% or less, and particularly preferably 0.01 wt% or less. When the saturated water absorption is within the above range, it is possible to reduce changes over time in optical properties such as retardation of a layer containing a polymer containing an alicyclic structure. In addition, it is possible to suppress deterioration of optical elements such as polarizing plates and liquid crystal display devices that include the processed film, and for example, it is possible to maintain stable and good display of image display devices over a long period of time.

[0053] The saturated water absorption is the mass increase of a sample immersed in water at a certain temperature for a certain period of time, expressed as a percentage of the mass of the test piece before immersion. It is usually measured by immersing the sample in water at 23°C for 24 hours. The saturated water absorption of a polymer can be adjusted to the above range, for example, by reducing the amount of polar groups in the polymer. Therefore, from the viewpoint of further reducing the saturated water absorption, it is preferable that the polymer containing an alicyclic structure does not have polar groups.

[0054] The amount of the polymer containing an alicyclic structure in the thermoplastic resin film is preferably 80.0 wt% or more, more preferably 85.0 wt% or more, particularly preferably 90.0 wt% or more, and is preferably 99.0 wt% or less, more preferably 97.0 wt% or less, particularly preferably 95.0 wt% or less. By keeping the amount of the polymer containing an alicyclic structure within the above range, the durability of optical elements such as polarizing plates equipped with the processed film under humid conditions can be improved.

[0055] Examples of optional components that can be contained in the thermoplastic resin include compounding agents such as ultraviolet absorbers, particles, colorants such as pigments and dyes, plasticizers, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, surfactants, etc. These may be used alone or in combination of two or more in any ratio.

[0056] The thermoplastic resin film preferably contains an ultraviolet absorber. The thermoplastic resin film may contain only one type of ultraviolet absorber, or may contain two or more types in any combination in any ratio. When the thermoplastic resin film contains an ultraviolet absorber, it can impart an ultraviolet absorbing function to the processed film and can also increase the temperature of the thermoplastic resin film in step (2) as described below.

[0057] Examples of the ultraviolet absorber that can be contained in the thermoplastic resin film include organic ultraviolet absorbers such as triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and acrylonitrile-based ultraviolet absorbers.

[0058] As the triazine-based ultraviolet absorber, for example, a compound having a 1,3,5-triazine ring can be preferably used. Specific examples of the triazine-based ultraviolet absorber include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol and 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine.

[0059] Examples of benzotriazole-based ultraviolet absorbers include 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol] (commercially available as "ADEKA STAB LA-31" manufactured by ADEKA Corporation), 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2-[5-chloro(2H)-benzotriazol-2-yl]- Examples include 4-methyl-6-(tert-butyl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-butylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazol-2-yl)-4-methyl-6-(3,4,5,6-tetrahydrophthalimidylmethyl)phenol, reaction products of methyl 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol 300, and 2-(2H-benzotriazol-2-yl)-6-(linear and branched dodecyl)-4-methylphenol.

[0060] More preferably, the thermoplastic resin film contains an ultraviolet absorber having an absorbance of 0.2 or more at least at one wavelength of the ultraviolet light irradiated onto the laminated film in step (2), which makes it possible to effectively increase the temperature of the thermoplastic resin film in step (2), as described below.

[0061] The thermoplastic resin film more preferably contains an ultraviolet absorber having an absorbance of 0.2 or more in at least a part of the wavelength range of 330 nm or more and 400 nm or less. This makes it possible to more effectively increase the temperature of the thermoplastic resin film in step (2), as will be described later.

[0062] An example of an ultraviolet absorber having an absorbance of 0.2 or more in at least a portion of the wavelength range of 330 nm or more and 400 nm or less is 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol]. The absorbance of the ultraviolet absorber in the wavelength range of 330 nm or more and 400 nm or less can be measured using an ultraviolet-visible spectrophotometer.

[0063] The absorbance of the ultraviolet absorber that can be contained in the thermoplastic resin film can be, for example, 0.99 or less over the entire wavelength range of 330 nm or more and 400 nm or less.

[0064] The content of the ultraviolet absorber in the thermoplastic resin film is preferably 4% by weight or more, more preferably 4.5% by weight or more, even more preferably 5% by weight or more, and preferably 7% by weight or less, more preferably 6.5% by weight or less, even more preferably 6% by weight or less, where the weight of the thermoplastic resin film is taken as 100% by weight. When the thermoplastic resin film contains multiple types of ultraviolet absorbers, the content refers to the total content of the multiple types of ultraviolet absorbers.

[0065] When the content of the ultraviolet absorber in the thermoplastic resin film is equal to or greater than the lower limit of the above range, the ultraviolet absorber generates heat upon irradiation with ultraviolet light in step (2), as described below, and the temperature of the thermoplastic resin film can be sufficiently increased, and the light durability of the optical element including the processed film can be effectively improved. When the content of the ultraviolet absorber in the thermoplastic resin film is equal to or less than the upper limit of the above range, the light transmittance of the optical element provided with the processed film can be increased.

[0066] When the thermoplastic resin film is a thermoplastic resin film 210 having a multilayer structure and the intermediate layer 211 contains an ultraviolet absorber, the content of the ultraviolet absorber in the intermediate layer 211 is preferably 1.0 wt % or more, more preferably 3.0 wt % or more, particularly preferably 5.0 wt % or more, and preferably 20.0 wt % or less, more preferably 15.0 wt % or less, particularly preferably 10.0 wt % or less. By making the amount of ultraviolet absorber in the intermediate layer equal to or greater than the lower limit of the above range, the durability of the optical element including the processed film to light such as ultraviolet light can be effectively improved, and by making it equal to or less than the upper limit of the above range, the light transmittance of the optical element including the processed film can be increased.

[0067] When the thermoplastic resin film is a thermoplastic resin film 210 having a multilayer structure, the surface layers 212, 213 may contain an ultraviolet absorber, but the amount of ultraviolet absorber in the surface layers is preferably small, and more preferably the surface layers do not contain an ultraviolet absorber. The content of the ultraviolet absorber in the surface layers is preferably 1 wt% or less, more preferably 0.5 wt% or less, even more preferably 0.1 wt% or less, and particularly preferably 0 wt%. In other words, it is particularly preferable that the surface layers do not contain an ultraviolet absorber. By not including an ultraviolet absorber in the surface layers, bleeding out of the ultraviolet absorber can be suppressed.

[0068] When the thermoplastic resin film contains an ultraviolet absorber, any method for producing the thermoplastic resin containing the ultraviolet absorber may be used, and examples include a method in which the ultraviolet absorber is blended into a thermoplastic polymer before producing the thermoplastic resin film by melt extrusion; a method in which a masterbatch containing a high concentration of ultraviolet absorber is used; and a method in which the ultraviolet absorber is blended into a thermoplastic polymer during production of the thermoplastic resin film by melt extrusion.

[0069] The thermoplastic resin film may contain particles, which makes it possible to easily adjust the haze of the processed film and the surface roughness of the thermoplastic resin film.

[0070] When the thermoplastic resin film has a multilayer structure and contains particles, it is preferable that the layer disposed on the surface of the thermoplastic resin film contains particles. That is, in the thermoplastic resin film 210, it is preferable that the surface layer 212 and the surface layer 213 contain particles.

[0071] The particles are preferably particles having a refractive index close to that of the polymer contained in the thermoplastic resin forming the thermoplastic resin film (when the thermoplastic resin film has a multilayer structure, the polymer contained in the surface layer containing the particles). Specifically, the absolute value of the difference between the refractive index of the particles contained in the thermoplastic resin film and the refractive index of the thermoplastic polymer (preferably a polymer containing an alicyclic structure) contained in the thermoplastic resin film is preferably 0.03 or less, more preferably 0.02 or less. By reducing the absolute value of the refractive index difference between the particles and the thermoplastic polymer (preferably a polymer containing an alicyclic structure) contained in the thermoplastic resin film as described above, light reflection on the particle surface can be suppressed. Therefore, the internal haze of the processed film can be easily reduced. Here, the refractive index of the particles may be higher or lower than that of the thermoplastic polymer.

[0072] It is preferable to use a material having the desired refractive index as the material for forming the particles. Examples of particle materials include inorganic materials such as silicon dioxide, titanium dioxide, magnesium oxide, calcium carbonate, magnesium carbonate, barium sulfate, and strontium sulfate; and organic materials such as polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, polystyrene, cellulose acetate, cellulose acetate propionate, and crosslinked products thereof. In the case of organic materials, the desired refractive index can be adjusted by blending the above materials. These materials may be used alone or in combination of two or more in any ratio.

[0073] The number-average particle size of the particles is preferably 0.10 μm or more, more preferably 0.30 μm or more, particularly preferably 0.50 μm or more, and preferably 1 μm or less, more preferably 0.90 μm or less, particularly preferably 0.85 μm or less. By keeping the number-average particle size of the particles within the above range, the surface roughness of the layer containing the particles and the external haze of the thermoplastic resin film can be appropriately adjusted, and the internal haze can also be easily adjusted to a predetermined range. Here, the number-average particle size of the particles can be measured by dynamic light scattering (NanotrakWave series: manufactured by Nikkiso Co., Ltd.) or electrical sensing zone method (Multisizer: manufactured by Beckman Coulter). Furthermore, when the thermoplastic resin film has a multilayer structure, the number-average particle sizes of the particles contained in each surface layer may be the same or different.

[0074] When the thermoplastic resin film 210 has a multilayer structure and each surface layer 212, 213 contains particles, the amount of the particles in the resin forming the surface layer is preferably 0.1 wt% or more, more preferably 0.3 wt% or more, even more preferably 0.4 wt% or more, particularly preferably 1 wt% or more, and preferably 8 wt% or less, more preferably 7.0 wt% or less, even more preferably 6.0 wt% or less, particularly preferably 5.5 wt% or less. By keeping the amount of particles in the surface layer within the above range, it is easy to appropriately adjust the surface roughness of the surface layer and the external haze of the thermoplastic resin film.

[0075] The thermoplastic resin film can be produced by any method. Examples of the method for producing the thermoplastic resin film include a melt extrusion method and a casting method. Among these methods, the melt extrusion method (or a co-extrusion method) is preferred because it has excellent production efficiency and can reduce the amount of volatile components remaining in the thermoplastic resin film.

[0076] When a thermoplastic resin film is produced by melt extrusion, examples of the extrusion method for the thermoplastic resin include the T-die method and the inflation method, with the T-die method being preferred due to its excellent productivity and thickness accuracy.

[0077] When the thermoplastic resin film has a multilayer structure, the thermoplastic resin film can be produced by, for example, a co-extrusion method, a co-casting method, etc. As a method for producing a thermoplastic resin film having a multilayer structure, a co-extrusion method is preferred because it has excellent production efficiency and can reduce the amount of volatile components remaining in the thermoplastic resin film.

[0078] The coextrusion method includes a coextrusion step in which resins for forming each layer of the thermoplastic resin film are coextruded. In the coextrusion step, the resins for forming each layer of the thermoplastic resin film are extruded in a layered form in a molten state. In this case, examples of resin extrusion methods include the coextrusion T-die method, the coextrusion inflation method, and the coextrusion lamination method. Among these, the coextrusion T-die method is preferred. The coextrusion T-die method includes a feedblock method and a multi-manifold method, and the multi-manifold method is particularly preferred in that it can reduce thickness variation.

[0079] In the extrusion step, the melting temperature of the extruded resin is preferably Tg1 + 80°C or higher, more preferably Tg1 + 100°C or higher, and preferably Tg1 + 180°C or lower, more preferably Tg1 + 170°C or lower. Here, "Tg1" represents the highest glass transition temperature of the polymer contained in the thermoplastic resin film. By setting the melting temperature of the extruded resin to be equal to or higher than the lower limit of the above range, the fluidity of the resin can be sufficiently increased to improve moldability, and by setting it to be equal to or lower than the upper limit, deterioration of the resin can be suppressed.

[0080] In the extrusion step, the temperature of the resin in the extruder is preferably Tg1 to (Tg1+100°C) at the resin inlet, preferably (Tg1+50°C) to (Tg1+170°C) at the extruder outlet, and the die temperature is preferably (Tg1+50°C) to (Tg1+170°C).

[0081] Furthermore, the arithmetic mean roughness of the die lip of the die used in the extrusion step is preferably 1.0 μm or less, more preferably 0.7 μm or less, and particularly preferably 0.5 μm or less. By keeping the arithmetic mean roughness of the die lip within this range, it becomes easy to suppress streak-like defects in the thermoplastic resin film.

[0082] In the melt extrusion method, a film-like molten resin extruded from a die lip is usually brought into close contact with a chill roll, where it is cooled and hardened. In this case, methods for bringing the molten resin into close contact with the chill roll include, for example, an air knife method, a vacuum box method, and an electrostatic contact method.

[0083] The number of cooling rolls is not particularly limited and is usually 2 or more. The cooling rolls may be arranged, for example, in a linear, Z-shape, or L-shape. In this case, the way in which the molten resin extruded from the die lip passes through the cooling rolls is not particularly limited.

[0084] As described above, the thermoplastic resin film formed into a film shape may be further subjected to a stretching treatment. That is, the thermoplastic resin film may be a film before being stretched, i.e., a pre-stretched film, or may be a film that has been stretched, i.e., a stretched film.

[0085] When the thermoplastic resin film is a stretched film, the stretching method is not particularly limited. The stretching may be a uniaxial stretching process in which stretching is performed in only one direction, or a biaxial stretching process in which stretching is performed in two different directions. Furthermore, the biaxial stretching process may be a simultaneous biaxial stretching process in which stretching is performed in two directions simultaneously, or a sequential biaxial stretching process in which stretching is performed in one direction and then in the other direction. Furthermore, the stretching may be performed in any of the following ways: longitudinal stretching in which stretching is performed in the longitudinal direction of the pre-stretched film; transverse stretching in which stretching is performed in the width direction of the pre-stretched film; and oblique stretching in which stretching is performed in an oblique direction that is neither parallel nor perpendicular to the width direction of the pre-stretched film, or a combination of these. Among these stretching processes, oblique stretching is preferred because it can easily adjust the orientation angle of the thermoplastic resin film to within the desired range. Examples of stretching methods include a roll method, a float method, and a tenter method.

[0086] The stretching temperature and stretching ratio can be set arbitrarily within a range that allows a thermoplastic resin film having the desired retardation to be obtained. Specifically, the stretching temperature is preferably Tg1-30°C or higher, more preferably Tg1-10°C or higher, and preferably Tg1+60°C or lower, more preferably Tg1+50°C or lower. The stretching ratio is preferably 1.01 to 30 times, preferably 1.01 to 10 times, more preferably 1.01 to 5 times. Here, Tg1 represents the highest glass transition temperature of the polymer contained in the thermoplastic resin film.

[0087] The thermoplastic resin film may be produced by a production method including any additional steps in addition to the steps described above.

[0088] The thermoplastic resin film is preferably long. When the thermoplastic resin film is long, a long laminate film and subsequently a long processed film can be produced continuously and efficiently from the thermoplastic resin film.

[0089] The thickness of the thermoplastic resin film is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, and is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 40 μm or less. By making the thickness of the thermoplastic resin film equal to or greater than the lower limit of the above range, the processed film can exhibit a retardation within the desired range, and by making the thickness equal to or less than the upper limit of the above range, the processed film can be made thinner.

[0090] When the thermoplastic resin film is a thermoplastic resin film 210 having a multilayer structure, the thickness of the intermediate layer is preferably 1.0 μm or more, more preferably 5.0 μm or more, particularly preferably 7.0 μm or more, and preferably 45 μm or less, more preferably 40 μm or less, even more preferably 36 μm or less, particularly preferably 30 μm or less. By making the thickness of the intermediate layer equal to or greater than the lower limit of the above range, the proportion of the ultraviolet absorber in the intermediate layer can be designed to be low, and by making the thickness equal to or less than the upper limit of the above range, the mechanical properties of the processed film can be improved.

[0091] When the thermoplastic resin film is a thermoplastic resin film 210 having a multilayer structure, the thickness of each of the surface layers 212, 213 is preferably 1.0 μm or more, more preferably 1.5 μm or more, even more preferably 2.0 μm or more, particularly preferably 3.0 μm or more, and preferably 10 μm or less, more preferably 9.0 μm or less, particularly preferably 8.0 μm or less. By setting the thickness of the surface layer within the above range, it is easy to appropriately adjust the surface roughness and external haze of the thermoplastic resin film. Here, the above-mentioned surface layer thickness range represents the thickness range of each surface layer.

[0092] When the thermoplastic film is a thermoplastic resin film 210 having a multilayer structure, the ratio of the thickness of the surface layer 212 or the thickness of the surface layer 213 to the thickness of the intermediate layer (surface layer / intermediate layer) is preferably 0.01 or more, more preferably 0.02 or more, even more preferably 0.03 or more, and preferably 0.17 or less, more preferably 0.12 or less, even more preferably 0.07 or less.

[0093] Here, the thickness of each layer contained in the thermoplastic resin film or processed film can be measured by the following method. A sample piece is prepared by embedding the thermoplastic resin film or processed film in epoxy resin. This sample piece is sliced ​​to a thickness of 0.05 μm using a microtome. The cross section revealed by slicing can then be observed under a microscope to measure the thickness of each layer contained in the thermoplastic resin film or processed film.

[0094] The thermoplastic resin film preferably has a surface roughness within a predetermined range. When the thermoplastic resin film has a multilayer structure, the surface of the layer disposed on the surface of the thermoplastic resin film (surface layers 212 and 213 in the thermoplastic resin film 210) preferably has a surface roughness within a predetermined range. Specifically, the arithmetic mean roughness of the surface of the thermoplastic resin film is preferably 5.0 nm or more, more preferably 5.5 nm or more, particularly preferably 6.0 nm or more, and preferably 20.0 nm or less, more preferably 15.0 nm or less, particularly preferably 10.0 nm or less. By making the arithmetic mean roughness of the surface of the thermoplastic resin film equal to or greater than the lower limit of the above range, streak-like defects in the processed film can be made less visible, while making it equal to or less than the upper limit of the above range can improve the visibility of a liquid crystal display device equipped with the processed film. When the processed film is produced by a process including a step of forming a layer of a liquid composition for forming a hard coat layer on the surface of the thermoplastic resin film, streak-like defects in the thermoplastic resin film may be accentuated after the liquid composition layer is formed. Therefore, it is particularly effective to set the arithmetic mean roughness of the surface of the thermoplastic resin film to be equal to or greater than the lower limit of the above range. Furthermore, it is preferable that at least one of the two main surfaces of the thermoplastic resin film (in the thermoplastic resin film 210, the surface of at least one of the surface layers 212 and 213) has an arithmetic mean roughness within the above range, and it is more preferable that all of the two main surfaces of the thermoplastic resin film (in the thermoplastic resin film 210, the surfaces of both surface layers 212 and 213) have an arithmetic mean roughness within the above range. Here, the surfaces of the surface layers 212 and 213 refer to the surfaces of the surface layers 212 and 213 opposite to the intermediate layer 211. The arithmetic mean roughness of the surface of the thermoplastic resin film can be measured using an interferometric surface roughness measuring device (Zygo's "NewView7300").

[0095] The thermoplastic resin film preferably has an internal haze of 0.5% or less and an external haze of 0.5% or more. By keeping the internal haze and external haze of the thermoplastic resin film within the predetermined ranges, the processed film can improve the visibility of images when used in image display devices such as liquid crystal display devices.

[0096] More specifically, the internal haze of the thermoplastic resin film is preferably 0.5% or less, more preferably 0.4% or less, and even more preferably 0.3% or less. By reducing the internal haze of the thermoplastic resin film in this way, the total haze of the entire thermoplastic resin film can be reduced, thereby suppressing display unevenness while maintaining good image clarity displayed on an image display device to which the processed film is applied. The lower limit of the internal haze of the thermoplastic resin film is arbitrary, but is preferably 0.01% or more, more preferably 0.02% or more.

[0097] The external haze of the thermoplastic resin film is preferably 0.5% or more, more preferably 0.6% or more. Such a large external haze of the thermoplastic resin film indicates that an uneven structure corresponding to the external haze is formed on the surface of the thermoplastic resin film. The action of such an uneven structure can suppress light interference that can cause display unevenness. Therefore, display unevenness of a display device to which the processed film is applied can be suppressed, thereby improving visibility. The upper limit of the external haze of the thermoplastic resin film is arbitrary, but from the viewpoint of suppressing the total haze of the entire thermoplastic resin film, it is preferably 5.0% or less, more preferably 3.0% or less, and particularly preferably 1.5% or less.

[0098] The internal haze and external haze of a thermoplastic resin film can be measured by the following method. A quartz cell with an optical path length of 10 mm is filled with a liquid having the same refractive index as the thermoplastic resin film. The thermoplastic resin film is cut into strips to prepare film pieces, which are then inserted into the quartz cell. The quartz cell is then placed in a haze meter, and the internal haze is measured. Furthermore, the total haze of the thermoplastic resin film is measured in accordance with JIS K7136, and the internal haze value is subtracted from the total haze value to calculate the external haze.

[0099] The total light transmittance of the thermoplastic resin film is preferably 85% to 100%, more preferably 87% to 100%, and particularly preferably 90% to 100%. The total light transmittance can be measured using a spectrophotometer in accordance with JIS K0115.

[0100] The light transmittance of the thermoplastic resin film at a wavelength of 380 nm is preferably 10% or less, more preferably 8.0% or less, and particularly preferably 5.0% or less. A thermoplastic resin film having such a low light transmittance at a wavelength of 380 nm has excellent ultraviolet blocking ability. Therefore, a processed film containing such a thermoplastic resin film can improve the durability of optical elements such as polarizing plates and liquid crystal panels that include the processed film, and can suppress deterioration due to ultraviolet rays.

[0101] (Before hardening layer) The pre-curing layer includes an ultraviolet curing resin. The ultraviolet-curable resin means a resin that cures when irradiated with ultraviolet light. The ultraviolet-curable resin usually contains a material containing a polymerizable group. The ultraviolet-curable resin may contain any of a monomer containing a polymerizable group, an oligomer containing a polymerizable group, and a polymer containing a polymerizable group. Hereinafter, the monomer containing a polymerizable group will also be referred to as a polymerizable monomer.

[0102] Any material containing a polymerizable group that can be contained in the UV-curable resin can be used as long as it can provide a hard coat layer with the desired hardness. Among these, the UV-curable resin preferably contains a polymerizable monomer as the material containing a polymerizable group, and more preferably contains a polymerizable monomer having three or more (meth)acryloyl groups per molecule. The UV-curable resin preferably contains 50% by weight or more of a polymerizable monomer having three or more (meth)acryloyl groups per molecule, with the total amount of polymerizable monomers in the UV-curable resin being 100% by weight. The hardness of the hard coat layer can be increased by using a UV-curable resin containing such a polymerizable monomer.

[0103] Examples of compounds having three or more (meth)acryloyl groups in one molecule include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and trimethylolpropane tri(meth)acrylate.

[0104] As the polymerizable monomer, a compound having three or more (meth)acryloyl groups in one molecule may be used alone or in combination of two or more in any ratio. For example, a combination of pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate, or a combination of dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate may be used.

[0105] In particular, it is preferable that the ultraviolet-curable resin contains a compound having four (meth)acryloyl groups in one molecule, a compound having five (meth)acryloyl groups in one molecule, and a compound having six (meth)acryloyl groups in a total amount of 80% by weight or more, with the total polymerizable monomers in the ultraviolet-curable resin being 100% by weight.

[0106] As the polymerizable monomer, any monomer compound may be used in combination with the compound having three or more (meth)acryloyl groups in one molecule. Examples of the optional monomer compound include compounds having two (meth)acryloyl groups in one molecule, such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and polyethylene glycol diacrylate; polyfunctional monomers containing an allyl group, such as allyl methacrylate, diallyl phthalate, and glycerin diallyl ether; bisphenoxyethanol fluorene diacrylate, 2-propenoic acid [5,5'-(9-fluoren-9-ylidene)bis(1,1'-biphenyl)-2-(polyoxyethylene) ester], and the like. Compounds having an aromatic ring and a (meth)acryloyl group, such as propenoic acid [5,5'-4-(1,1'-biphenylyl)methylenebis(1,1'-biphenyl)-2-(polyoxyethylene) ester]; and alkyl (meth)acrylates having 1 to 30 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. These may be used alone or in combination of two or more in any ratio.

[0107] Furthermore, the UV-curable resin preferably contains an oligomer and / or polymer containing a polymerizable group as the material containing a polymerizable group, and more preferably contains a polyfunctional urethane acrylate, which is a polymerization reaction product of a diisocyanate and a polyol having a (meth)acryloyl group. When the UV-curable resin contains a polyfunctional urethane acrylate, the UV-curable resin contains preferably 30 parts by weight or more, more preferably 40 parts by weight or more, and preferably 200 parts by weight or less, more preferably 150 parts by weight or less of the polyfunctional urethane acrylate per 100 parts by weight of the polymerizable monomer.

[0108] The material containing the polymerizable group can usually be polymerized by irradiation with active energy rays such as ultraviolet rays. Therefore, the ultraviolet-curable resin preferably contains a photopolymerization initiator in addition to the material containing the polymerizable group.

[0109] Examples of the photopolymerization initiator include benzoin derivatives, benzil ketals, α-hydroxyacetophenones, α-aminoacetophenones, acylphosphine oxides, o-acyloximes, etc. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination at any ratio.

[0110] The amount of the photopolymerization initiator is preferably 1 part by weight or more, more preferably 2 parts by weight or more, even more preferably 2.5 parts by weight or more, particularly preferably 3 parts by weight or more, and is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, particularly preferably 5 parts by weight or less, relative to 100 parts by weight of the polymerizable monomer.

[0111] The pre-curing layer may contain, in addition to the ultraviolet-curable resin, further optional components as needed. Examples of optional components that the pre-curing layer may contain include fine particles. The fine particles may be organic fine particles or inorganic fine particles such as metal oxide fine particles. From the viewpoint of effectively reducing curling of the processed film, the pre-curing layer preferably contains fine particles, more preferably inorganic fine particles, and even more preferably metal oxide fine particles. The number average particle diameter of the fine particles may be, for example, 30 nm or more and 5 μm or less. The number average particle diameter of the fine particles may be measured, for example, using a laser diffraction particle size distribution analyzer.

[0112] The amount of the microparticles is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, even more preferably 23 parts by weight or more, even more preferably 30 parts by weight or more, and is preferably 60 parts by weight or less, more preferably 50 parts by weight or less, even more preferably 40 parts by weight or less, relative to 100 parts by weight of the polymerizable monomer.

[0113] The laminated film containing the thermoplastic resin film and the pre-curing layer can be produced by any method. The laminated film can be produced, for example, by a production method including a step of applying a liquid composition for forming a pre-cured layer onto a thermoplastic resin film to form a film of the liquid composition.

[0114] The liquid composition for forming the pre-cured layer contains the ultraviolet-curable resin and optional components such as fine particles, etc. The liquid composition may contain a solvent in addition to the ultraviolet-curable resin. The solvent is preferably one that can dissolve materials containing polymerizable groups, such as polymerizable monomers, and that is easily volatilizable. Examples of such solvents include water; alcohols such as methanol, ethanol, propanol, butanol, isopropanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, and isopropyl glycol; esters such as methyl acetate and ethyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetoacetate, and cyclohexanone; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; aromatic compounds such as toluene and xylene; and isophorone. The solvent may be used alone or in combination of two or more in any ratio.

[0115] The amount of solvent is preferably set so that the solids concentration of the liquid composition for producing the pre-curing layer falls within the desired range. The solids concentration of the liquid composition is preferably 10% by weight or more, more preferably 20% by weight or more, particularly preferably 30% by weight or more, and preferably 70% by weight or less, more preferably 55% by weight or less. By keeping the solids concentration within the above range, it is easy to keep the thickness of the hard coat layer within an appropriate range, and it is easy to produce a hard coat layer with sufficient excellent adhesion. Furthermore, since the haze of the hard coat layer can usually be reduced, the transparency of the processed film can be improved. Furthermore, cracks in the hard coat layer and warping of the processed film can usually be reduced. Furthermore, since the viscosity of the liquid composition for producing the pre-curing layer can be reduced, the coatability of the liquid composition can be improved. Therefore, the surface flatness of the hard coat layer can be improved, and the occurrence of streaks can be suppressed.

[0116] The method for applying the liquid composition for forming the pre-cured layer onto the thermoplastic resin film is not particularly limited, and examples of the application method include bar coating, slot coating, spin coating, roll coating, curtain coating, and screen printing.

[0117] The method for producing the laminated film may include any further steps in addition to the steps described above.

[0118] For example, before the liquid composition for producing the pre-curing layer is applied to the thermoplastic resin film, the main surface of the thermoplastic resin film may be subjected to a surface treatment such as a corona treatment.

[0119] Furthermore, after the liquid composition for producing the pre-cured layer is applied onto the main surface of the thermoplastic resin film, the solvent may be removed from the film of the liquid composition by drying, if necessary. The method for removing the solvent from the film of the liquid composition is not particularly limited, and examples thereof include air drying, heat drying, drying under reduced pressure, and combinations thereof. For example, the temperature at which the film of the liquid composition is dried may be, for example, 90°C or higher, for example, 100°C or higher, for example, 110°C or higher, and may be, for example, 130°C or lower. The drying time of the film of the liquid composition may be, for example, 10 seconds or more, for example, 20 seconds or more, for example, 30 seconds or more, and may be, for example, 2 minutes or less.

[0120] <3. Process (2)> Step (2) will be described in more detail below. In step (2), the laminated film is irradiated with ultraviolet light to obtain the processed film. By irradiating the laminated film with ultraviolet light, the ultraviolet curable resin contained in the pre-curing layer is cured to form a hard coat layer.

[0121] In the manufacturing method of this embodiment, the amount of curl can be reduced even when the cumulative light amount of ultraviolet light irradiated onto the laminated film is large. To achieve this effect, the cumulative light amount of ultraviolet light irradiated onto the laminated film is preferably 200 mJ / cm in the measurement wavelength range of 320 nm to 390 nm. 2 More preferably, 200 mJ / cm 2 more preferably more than 250 mJ / cm 2 More preferably, 250 mJ / cm 2 more preferably more than 300 mJ / cm 2 or more, preferably 660 mJ / cm 2 The following is the result.

[0122] The method of irradiating the laminated film with ultraviolet rays is not particularly limited, and may be carried out using an ultraviolet irradiation lamp such as a high-pressure mercury lamp or an LED-UV lamp. Among these, it is preferable to use a high-pressure mercury lamp, as it is capable of irradiating the laminated film with ultraviolet rays over a wide range of wavelengths.

[0123] The laminated film is preferably irradiated with ultraviolet light so that the ultraviolet light is incident on the uncured layer side of the laminated film.

[0124] Step (2) includes the temperature of the thermoplastic resin film increasing to soften the thermoplastic resin film, the pre-curing layer being irradiated with ultraviolet light curing and simultaneously undergoing cure shrinkage, and the softened thermoplastic resin film shrinking in the in-plane direction following the cure shrinkage in the in-plane direction of the pre-curing layer.

[0125] "Following the cure shrinkage in the in-plane direction of the pre-curing layer" means that the thermoplastic resin film shrinks in the in-plane direction substantially simultaneously with the cure shrinkage in the in-plane direction of the pre-curing layer. The degree of shrinkage of the thermoplastic resin film in the in-plane direction is usually about the same as the cure shrinkage in the in-plane direction of the pre-curing layer. "Shrinking substantially simultaneously with the cure shrinkage" of the thermoplastic resin film means that the thermoplastic resin film shrinks by the end of the ultraviolet irradiation in step (2), and includes cases where the thermoplastic resin film shrinks preferably 5 seconds or less, more preferably 1 second or less, later than the cure shrinkage of the pre-curing layer, and most preferably, the thermoplastic resin film shrinks without any delay compared to the cure shrinkage of the pre-curing layer.

[0126] As described above, the thermoplastic resin film is formed of a thermoplastic resin that can be plastically deformed by heating, and therefore, when the temperature of the thermoplastic resin film rises, the thermoplastic resin film softens. When the pre-curing layer provided in contact with the main surface of the thermoplastic resin film undergoes cure shrinkage at least in the in-plane direction due to the softening of the thermoplastic resin film, the thermoplastic resin film can shrink in the in-plane direction in response to the cure shrinkage.

[0127] Examples of methods for increasing the temperature of a thermoplastic resin film include a method in which the thermoplastic resin film contains an ultraviolet absorber, and a method in which the thermoplastic resin film is heated by a heating means. Either one of these methods may be used, or these methods may be combined.

[0128] An example of a method for heating a thermoplastic resin film is a method of heating a backup roll when irradiating a laminate film with ultraviolet rays. The backup roll refers to a roll that supports the laminate film when irradiating the laminate film with ultraviolet rays. By heating the backup roll, the thermoplastic resin film included in the laminate film supported by the backup roll can be heated when irradiated with ultraviolet rays.

[0129] In step (2), it is preferable to raise the temperature of the thermoplastic resin film to preferably Tg2-50°C or higher, more preferably Tg2-48°C or higher, even more preferably Tg2-46°C or higher, and preferably Tg2 or lower. When the temperature of the thermoplastic resin film is within this range, the shrinkage of the thermoplastic resin film tends to follow the cure shrinkage of the pre-cured layer. In addition, the occurrence of wrinkles in the processed film due to deformation of the thermoplastic resin film can be effectively suppressed.

[0130] Here, Tg2 represents the glass transition temperature of the thermoplastic resin film. The glass transition temperature of the thermoplastic resin film means the glass transition temperature of the resin forming the thermoplastic resin film. The glass transition temperature of the thermoplastic resin film can be measured using a differential scanning calorimeter in accordance with JIS K7121 at a temperature rise rate of 10°C / min.

[0131] In step (2), the temperature of the thermoplastic resin film is increased to, for example, 90° C. or higher. The upper limit of the temperature of the thermoplastic resin film may be, for example, 300° C. or lower.

[0132] When the thermoplastic resin film contains an ultraviolet absorber, the ultraviolet absorber absorbs the ultraviolet energy upon irradiation with ultraviolet light in step (2), generating heat and increasing the temperature of the thermoplastic resin film. From the viewpoint of efficiently increasing the temperature of the thermoplastic resin film, the thermoplastic resin film preferably contains an ultraviolet absorber, more preferably contains an ultraviolet absorber having an absorbance of 0.2 or more at least in one wavelength of the ultraviolet light irradiated onto the laminated film in step (2), and even more preferably contains an ultraviolet absorber having an absorbance of 0.2 or more in at least a part of the wavelength range of 330 nm to 400 nm. Examples of ultraviolet absorbers that can be contained in the thermoplastic resin film and the preferred content of the ultraviolet absorber are as described above.

[0133] When the thermoplastic resin film contains an ultraviolet absorber having an absorbance of at least a certain wavelength of ultraviolet light, specifically 0.2 or more, the ultraviolet absorber generates heat when irradiated with ultraviolet light of that wavelength, effectively raising the temperature of the thermoplastic resin film. Therefore, when the thermoplastic resin film contains an ultraviolet absorber having an absorbance of at least 0.2 at at least one wavelength of ultraviolet light irradiated onto the laminated film in step (2), the temperature of the thermoplastic resin film can be effectively raised in step (2).

[0134] Furthermore, if the thermoplastic resin film contains an ultraviolet absorber having an absorbance of 0.2 or more for ultraviolet light with a relatively long wavelength, specifically, an ultraviolet absorber having an absorbance of 0.2 or more in at least a portion of the wavelength range of 330 nm or more and 400 nm or less, the temperature of the thermoplastic resin film can be raised more effectively in step (2).

[0135] When the content of the ultraviolet absorber in the thermoplastic resin film is within the above-mentioned specified range, the ultraviolet absorber generates heat upon irradiation with ultraviolet rays in step (2), and the temperature of the thermoplastic resin film can be sufficiently increased.

[0136] <Processed film obtainable by the manufacturing method of this embodiment> The manufacturing method of this embodiment makes it possible to obtain a processed film with a small amount of curl. The processed film includes the thermoplastic resin film and a hard coat layer provided in contact with a main surface of the thermoplastic resin film. The hard coat layer is a layer having high hardness, and by providing the hard coat layer, it is possible to prevent the surface of the processed film from being scratched. The hardness of the hard coat layer can be expressed in terms of JIS pencil hardness. The specific JIS pencil hardness of the hard coat layer is preferably B or higher, more preferably HB or higher, and particularly preferably H or higher. By increasing the JIS pencil hardness of the hard coat layer as described above, the scratch resistance of the hard coat laminate can be improved. Here, the JIS pencil hardness is the hardness of the pencil at which scratches begin to appear when the surface of the layer is scratched with pencils of various hardnesses tilted at a 45° angle and a load of 500 g is applied from above, in accordance with JIS K5600-5-4.

[0137] The thickness of the hard coat layer is preferably 1.0 μm or more, more preferably 1.5 μm or more, even more preferably 2 μm or more, even more preferably 3 μm or more, and preferably 10.0 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less, and particularly preferably 6 μm or less. By keeping the thickness of the hard coat layer within the above range, the amount of curl of the processed film can be effectively reduced, and the adhesion of the hard coat layer can be ensured. Furthermore, the scratch resistance of the hard coat layer can usually be improved.

[0138] The thickness of the thermoplastic resin film contained in the processed film can be within the same range as the preferred range of the thickness of the thermoplastic resin film described above.

[0139] The ratio of the thickness of the hard coat layer to the thickness of the thermoplastic resin film (hard coat layer / thermoplastic resin film) is preferably 1 / 50 or more, more preferably 1 / 25 or more, particularly preferably 1 / 12 or more, and is preferably 3 / 10 or less, more preferably 1 / 5 or less. By keeping the ratio of the thickness of the hard coat layer to the thickness of the thermoplastic resin film within the above range, the amount of curl of the processed film can be further stably reduced.

[0140] The processed film may have any layer in combination with the thermoplastic resin film and the hard coat layer. For example, the processed film may have an anti-reflection layer on the hard coat layer. The processed film may also have an easy-adhesion layer on the surface of the thermoplastic resin film opposite the hard coat layer.

[0141] The processed film with a small amount of curl that can be obtained by the manufacturing method of this embodiment has excellent productivity when processed by a roll-to-roll process. Specifically, because the processed film has a small amount of curl, it is less likely to be damaged when being set into the manufacturing device, when being wound up, and when the processed film is cut after winding is completed, and it has excellent handleability. Therefore, the processed film that can be obtained by the manufacturing method of this embodiment can be easily processed in a long and / or wide state.

[0142] The applications of the processed film obtainable by the manufacturing method of this embodiment are not particularly limited, and for example, it can be used as a polarizing plate in combination with a polarizer in an image display device such as a liquid crystal display device. [Example]

[0143] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the examples shown below, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0144] In the following description, the units "%" and "parts" that represent amounts are by weight unless otherwise specified. Furthermore, the operations described below were carried out at room temperature (20°C ± 15°C) and atmospheric pressure (1 atm) unless otherwise specified.

[0145] <Evaluation method> (glass transition temperature) The glass transition temperature of the polymer or resin was measured using a differential scanning calorimeter "DSC7020" (Hitachi Measurements were carried out using a thermocouple (manufactured by Hi-Tech Science Co., Ltd.) in accordance with JIS K7121 under conditions of a temperature rise rate of 10°C / min and a temperature range of 0°C to 200°C.

[0146] (Thickness measurement method) The thickness of the thermoplastic resin film and the processed film was measured with a contact type film thickness meter (a dial gauge manufactured by Mitutoyo Corporation). The thickness of each layer contained in the thermoplastic resin film was measured by embedding the film in epoxy resin, slicing it into slices with a thickness of 0.05 μm using a microtome, and observing the cross section using a microscope. The thickness of the hard coat layer was calculated by measuring the total thickness of the processed film including the hard coat layer and subtracting the thickness of the thermoplastic resin film from the total thickness.

[0147] (Method for measuring curl of processed film) The processed films obtained in the examples and comparative examples were cut into 10 cm x 10 cm squares to obtain film pieces. The curl heights at the four corners of these film pieces were measured using a ruler to obtain the curl amount. Curling toward the surface of the hard coat layer was recorded as a positive value. Curling toward the opposite side of the surface of the hard coat layer was recorded as a negative value. In addition, when the film piece was significantly curled into a cylindrical shape, the diameter of the cylinder was measured using a ruler to obtain an index of the degree of curl.

[0148] Example 1 <1-1. Manufacturing of thermoplastic resin film> (Preparation of material for intermediate layer (a)) 95 parts by weight of Zeonor 1600 (glass transition temperature 160°C, refractive index 1.53) manufactured by Zeon Corporation and 5 parts by weight of an ultraviolet absorber (ADEKA STAB LA-31 (2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] manufactured by ADEKA Corporation) were fed into a co-rotating twin-screw extruder (TEX-44αII manufactured by The Japan Steel Works, Ltd., inner diameter DΦ=25 mm, barrel length L / D=42) and kneaded at a kneading temperature of 260°C to obtain resin (A) for forming an intermediate layer. Resin (A) was extruded in the form of strands from a twin-screw extruder and molded using a pelletizer to obtain pellets of resin (A). "ZEONOR 1600" is a resin containing an alicyclic structure-containing polymer (norbornene-based polymer). "ADK STAB LA-31" is a benzotriazole-based ultraviolet absorber.

[0149] (Preparation of surface layer material) 95 parts by weight of Zeon Corporation's "ZEONOR 1600" (glass transition temperature 160 °C, refractive index 1.53, resin containing norbornene polymer) as resin (B) and 5 parts by weight of Sekisui Plastics Co., Ltd.'s polymer beads "TECHPOLYMER" (number average particle diameter 0.5 μm, refractive index 1.53) as particles C were fed into a co-rotating twin-screw extruder (Japan Steel Works, Ltd.'s "TEX-44αII", inner diameter DΦ = 25 mm, barrel length L / D = 42) equipped with a vent port. The mixture was kneaded at a kneading temperature of 270 °C while venting at a suction pressure of 20 kPa (absolute pressure) through the vent port to obtain a kneaded product of particles C and resin (B) (resin (B')). The axial length Lv from the outlet of the twin-screw extruder to the vent port where venting was performed, divided by the inner diameter D of the twin-screw extruder (Lv / D), was 3. Resin (B') was extruded in the form of a strand from a twin-screw extruder and molded with a pelletizer to obtain pellets (pr) of resin (B') for forming the surface layer. Techpolymer is a microparticle of a cross-linked copolymer of methyl methacrylate and styrene. The absolute value of the difference between the refractive index nb of resin (B) and the refractive index nc of the organic microparticles (|nb-nc|) is 0.

[0150] (Production of thermoplastic resin films) A thermoplastic resin film was produced by coextrusion using a two-type, three-layer multilayer extruder (manufactured by Shibaura Machine Co., Ltd.) equipped with a feed block. The feed block was designed to form a laminate having a three-layer structure of surface layer (b1), intermediate layer (a), and surface layer (b2). The feed block was connected to a first single-screw extruder for melting the resin for forming the intermediate layer (a) to obtain molten resin (A') and extruding this, and a second single-screw extruder for melting the resins for forming the surface layers (b1) and (b2) to obtain molten resin (B') and extruding this. Pellets of resin (A) were supplied to the first single-screw extruder as the resin for the intermediate layer (a), and pellets (pr) of resin (B') were supplied to the second single-screw extruder as the resin for the surface layers (b1) and (b2). The laminated molten resin was extruded from a die connected to a feed block onto a cooling roll and cooled to obtain a 40 μm thick thermoplastic resin film, which was a laminate comprising a surface layer (b1), an intermediate layer (a), and a surface layer (b2) in this order. The resin temperature during extrusion was 265°C, and the cooling roll temperature was 130°C. The extrusion conditions were adjusted so that the thicknesses of the surface layer (b1) and the surface layer (b2) were each 2 μm, the thickness of the intermediate layer (a) was 36 μm, and the total thickness of the thermoplastic resin film was 40 μm. Both the resin (A) forming the intermediate layer and the resin (B') forming the surface layer contain 95% by weight of "ZEONOR 1600", and the content of ultraviolet absorber in the thermoplastic resin film calculated assuming that the specific gravities of the resins (A) and (B') are the same was 4.5% by weight.

[0151] <1-2. Step (1): Preparation of laminated film> (Preparation of Liquid Composition for Hard Coat Layer) A UV-curable polymerizable monomer composition (R1) containing dipentaerythritol hexaacrylate (hereinafter sometimes abbreviated as "DP6A"), dipentaerythritol pentaacrylate (hereinafter sometimes abbreviated as "DP5A"), and dipentaerythritol tetraacrylate (hereinafter sometimes abbreviated as "DP4A") was prepared. In this polymerizable monomer composition (R1), the weight ratio of each component was DP6A / DP5A / DP4A = 64 / 17 / 19. The solids concentration of the polymerizable monomer composition (R1) was 100%.

[0152] A multifunctional urethane acrylate (U1) was prepared, which was a urethane reaction acrylate of 222 parts by weight of isophorone diisocyanate and 795 parts by weight of a mixture (PE3A / PE4A = 75 / 25 (weight ratio)) of pentaerythritol triacrylate (hereinafter sometimes abbreviated as "PE3A") and pentaerythritol tetraacrylate (hereinafter sometimes abbreviated as "PE4A"). The solids concentration of this multifunctional urethane acrylate (U1) was 100%.

[0153] A mixed ethanol mixture of ethanol, normal propyl alcohol, methanol, and water was prepared. The weight ratio of each component in this mixed ethanol was ethanol / normal propyl alcohol / methanol / water = 85.5 / 9.6 / 4.9 / 0.2.

[0154] 29.4 parts by weight of the polymerizable monomer composition (R1), 12.6 parts by weight of the polyfunctional urethane acrylate (U1) (42.9 parts by weight per 100 parts by weight of composition (R1)), 11.0 parts by weight of methyl ethyl ketone, 2.0 parts by weight of the mixed ethanol, 1.6 parts by weight of diacetone alcohol, and 0.86 parts by weight of a photopolymerization initiator (BASF Japan Ltd. "Irgacure 184" solids content 100%) (2.9 parts by weight per 100 parts by weight of composition (R1)) were thoroughly mixed to obtain a mixture. To this mixture, 35.0 parts by weight of a dispersion of metal oxide particles (P1) (20% solids, number average particle diameter 60 nm) (23.8 parts by weight of metal oxide particles per 100 parts by weight of composition (R1)), and 0.24 parts by weight of an acrylic surfactant (100% solids) were added and mixed uniformly to obtain a liquid composition (H1) for the hard coat layer. (Solid content in liquid composition (H1) 50.1 parts by weight (solid content concentration 54.0% by weight))

[0155] (Formation of pre-hardening layer) One side of the thermoplastic resin film obtained in <1-1> was subjected to corona treatment (output 0.4 kW, discharge rate 200 W min / m 2 ) was subjected to a corona treatment. A liquid composition (H1) for a hard coat layer was applied to the corona-treated surface of the thermoplastic resin film using a bar coater in an environment of 50% relative humidity so that the thickness of the hard coat layer obtained after curing would be approximately 4 to 6 μm. The applied film of liquid composition (H1) was then dried at 120°C for 1 minute to form a pre-curing layer on the main surface of the thermoplastic resin film, thereby obtaining a laminated film comprising a thermoplastic resin film and a pre-curing layer.

[0156] <1-3. Process (2): Ultraviolet irradiation> The laminated film comprising the thermoplastic resin film and the pre-curing layer was irradiated with a high-pressure mercury lamp at a peak irradiance of 330 mW / cm 2 , cumulative light intensity 200mJ / cm 2The pre-curing layer was cured by irradiating it with light (measurement wavelength range: 320 nm to 390 nm) to form a hard coat layer. This resulted in a processed film having a thermoplastic resin film and a hard coat layer. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured using the above-mentioned methods.

[0157] <Example 2> In the above <1-3>, the cumulative amount of ultraviolet light irradiation when curing the pre-curing layer is 460 mJ / cm 2 Except for the above, a processed film was obtained in the same manner as in Example 1. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured by the methods described above.

[0158] Example 3 In the above <1-3>, the cumulative amount of ultraviolet light irradiation when curing the pre-curing layer is 660 mJ / cm 2 Except for the above, a processed film was obtained in the same manner as in Example 1. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured by the methods described above.

[0159] <Comparative Example 1> In the above <1-2>, a cycloolefin polymer film (ZF16-040 manufactured by Nippon Zeon Co., Ltd., thickness 40 μm) was used as the thermoplastic resin film instead of the thermoplastic resin film obtained in the above <1-1>. In the above <1-3>, the cumulative amount of ultraviolet light irradiation when curing the pre-curing layer is 100 mJ / cm 2 was changed to. Except for the above, a processed film was obtained in the same manner as in Example 1. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured by the methods described above.

[0160] <Comparative Example 2> In the above <1-2>, a cycloolefin polymer film (ZF16-040 manufactured by Nippon Zeon Co., Ltd., thickness 40 μm) was used as the thermoplastic resin film instead of the thermoplastic resin obtained in the above <1-1>. In the above <1-3>, the cumulative amount of ultraviolet light irradiation when curing the pre-curing layer is set to 200 mJ / cm 2 was changed to. Except for the above, a processed film was obtained in the same manner as in Example 1. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured by the methods described above.

[0161] <Comparative Example 3> In the above <1-2>, a cycloolefin polymer film (ZF16-040 manufactured by Nippon Zeon Co., Ltd., thickness 40 μm) was used as the thermoplastic resin film instead of the thermoplastic resin obtained in the above <1-1>. In the above <1-3>, the cumulative amount of ultraviolet light irradiation when curing the pre-curing layer is 460 mJ / cm 2 was changed to. Except for the above, a processed film was obtained in the same manner as in Example 1. The thickness of the hard coat layer provided on the processed film and the curl amount of the processed film were measured by the methods described above.

[0162] <Result> The manufacturing conditions and evaluation results are shown in the table below. In the table below, the abbreviations have the following meanings: "UVA": ultraviolet absorber "Base material": Thermoplastic resin film "HC layer": Hard coat layer In the "Curl" section of the table below, the "φ" before the numerical value indicates that the evaluated film piece has curled significantly to form a cylinder, and the numerical value after the "φ" indicates the diameter of the cylinder.

[0163] [Table 1]

[0164] The processed films produced by the production methods according to Examples 1 to 3 have a small amount of curl, with the absolute value of the curl being 35 mm or less. On the other hand, the processed films produced by the production methods according to Comparative Examples 1 to 3 have significantly larger curl amounts than those of Examples 1 to 3. [Explanation of symbols]

[0165] 100 Laminated Film 110 Thermoplastic resin film 110U main surface 120 Pre-curing layer 200 Laminated Film 210 Thermoplastic resin film 210U main surface 211 Middle Class 211U main surface 211D main surface 212,213 surface layer

Claims

1. A method for producing a processed film comprising a thermoplastic resin film and a hard coat layer provided in contact with a main surface of the thermoplastic resin film, the method comprising: A step (1) of preparing a laminated film including the thermoplastic resin film and a pre-curing layer including an ultraviolet-curable resin provided in contact with a main surface of the thermoplastic resin film; and A step (2) of irradiating the laminated film with ultraviolet light to obtain the processed film; The step (2) the temperature of the thermoplastic resin film is increased to soften the thermoplastic resin film; The pre-curing layer irradiated with ultraviolet light undergoes curing and shrinkage at the same time; and A method for producing a processed film, comprising shrinking the softened thermoplastic resin film in an in-plane direction in response to cure shrinkage of the pre-curing layer in the in-plane direction.

2. The ultraviolet irradiation to the laminated film in the step (2) is 300 mJ / cm ２ More than 660mJ / cm ２ The method for producing a processed film according to claim 1, wherein the method is carried out at the following integrated light amount:

3. The method for producing a processed film according to claim 2 , wherein the thermoplastic resin film contains an ultraviolet absorber.

4. The method for producing a processed film according to claim 1 , wherein the thermoplastic resin film contains an ultraviolet absorber in an amount of 4% by weight or more and 7% by weight or less.

5. The method for producing a processed film according to claim 3 or 4, wherein the absorbance of the ultraviolet absorber is 0.2 or more in at least a part of the measurement wavelength range of 330 nm or more and 400 nm or less.

6. The method for producing a processed film according to claim 1 , wherein the thermoplastic resin film contains a polymer containing an alicyclic structure.

7. The method for producing a processed film according to claim 1 , wherein the pre-cured layer contains fine particles.

8. The method for producing a processed film according to claim 1, wherein the thickness of the thermoplastic resin film is 15 μm or more and 100 μm or less.

9. The method for producing a processed film according to claim 1 , wherein the hard coat layer has a thickness of 1.0 μm or more and 10.0 μm or less.

10. In the step (2), the temperature of the thermoplastic resin film is controlled to Tg ２ -50°C or higher (Tg ２ The method for producing a processed film according to claim 1, wherein t represents the glass transition temperature of the thermoplastic resin film.

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