Multilayer optical film, hard-coated optical film containing the same, and methods for manufacturing the same.

Abstract

To provide a multilayer optical film containing an ultraviolet absorber that exhibits excellent adhesion to a hard coat layer. [Solution] A multilayer optical film comprising a first outer layer, an inner layer, and a second outer layer in this order, wherein the inner layer comprises an ultraviolet absorber and a polymer comprising an alicyclic structure, the first outer layer and the second outer layer are each located on the outermost part of the multilayer optical film, have a thickness of 200 nm to 500 nm, contain a polymer comprising an alicyclic structure, have a content of 0.01% by weight or less of the ultraviolet absorber, have a content R1 of the ultraviolet absorber in the center of the thickness direction of the inner layer of 1% by weight or more and 20% by weight or less, and the percentage (R2 / R1 × 100) of the content R2 of the ultraviolet absorber at a depth of 750 nm of the multilayer optical film relative to the content R1 is 5% or more.

Description

Technical Field

[0001] The present invention relates to a multilayer optical film, a hard coat optical film containing the same, and a method for producing these.

Background Art

[0002] A resin film containing a resin is used as an element constituting an optical member due to characteristics such as high transparency. On the other hand, since a resin film is likely to deteriorate by irradiation with ultraviolet rays, it may be used as an optical film by containing an ultraviolet absorber in the resin film. It is known to make an optical film have a multilayer structure and contain an ultraviolet absorber in an intermediate layer (see Patent Documents 1 to 3, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a hard coat layer having high hardness is provided on an optical film, damage to the surface of the optical film can be reduced. If the hard coat layer peels off from the optical film, damage to the optical film may occur. Therefore, it is preferable that the adhesion between the optical film and the hard coat layer is high. However, when an ultraviolet absorber is contained in an intermediate layer in a multilayer optical film having a three-layer structure, the adhesion between the multilayer optical film and the hard coat layer may decrease.

[0005] Therefore, a multilayer optical film containing an ultraviolet absorber that has excellent adhesion to a hard coat layer; a hard-coated optical film comprising the multilayer optical film and a hard coat layer, having excellent adhesion between the multilayer optical film and the hard coat layer; a method for manufacturing the multilayer optical film; and a method for manufacturing the hard-coated optical film. [Means for solving the problem]

[0006] The inventors of this invention have diligently studied to solve the aforementioned problems. The inventors have found that when an ultraviolet absorber is included in an intermediate layer of a multilayer optical film, some of the ultraviolet absorber migrates to the outermost surface of the multilayer optical film, and this migrated ultraviolet absorber can cause a decrease in adhesion. Further investigation by the inventors has revealed that when the content of the ultraviolet absorber in the multilayer optical film has a specific distribution in the thickness direction of the multilayer optical film, the adhesion between the multilayer optical film and the hard coat layer is excellent. Based on these findings, the inventors completed the present invention. In other words, the present invention provides the following:

[0007] <1> A multilayer optical film comprising a first outer layer, an inner layer, and a second outer layer in this order, The inner layer comprises an ultraviolet absorber and a polymer containing an alicyclic structure. The first outer layer and the second outer layer are each positioned on the outermost surface of the multilayer optical film, have a thickness of 200 nm to 500 nm, contain a polymer including an alicyclic structure, and have a UV absorber content of 0.01% by weight or less. The content R1 of the ultraviolet absorber in the central part of the thickness direction of the inner layer is 1% by weight or more and 20% by weight or less. A multilayer optical film in which the percentage (R2 / R1 × 100) of the ultraviolet absorber content R2 at a depth of 750 nm relative to the content R1 is 5% or more. <2> The multilayer optical film described in <1>, comprising a first fine particle layer, the inner layer, and a second fine particle layer in this order, The first fine particle layer includes the first outer layer, The second fine particle layer includes the second outer layer, Each of the first fine particle layer and the second fine particle layer contains a polymer containing an alicyclic structure and fine particles (P) at a content of 2% by weight or more and 7% by weight or less, the distance between the fine particles (P) is 300 nm or more and 1000 nm or less, and the major axis length L of the fine particles (P) p of the thickness t of the first fine particle layer b1 The ratio (L p / t b1 ) and the major axis length L of the fine particles (P) p of the thickness t of the second fine particle layer b2 The ratio (L p / t b2 ) is 0.30 or less. The multilayer optical film according to <1>. <3> The fine particles (P) have an average primary particle diameter of 0.10 μm or more and 0.80 μm or less. The multilayer optical film according to <2>. <4> Either or both of the thickness t b1 and the thickness t b2 is 1.0 μm or more and 5.0 μm or less. The multilayer optical film according to <2> or <3>. <5> A hard coat optical film including the multilayer optical film according to <1> and a hard coat layer provided on the multilayer optical film. <6> A hard coat optical film including the multilayer optical film according to any one of <2> to <4> and a hard coat layer provided on the multilayer optical film. <7> A method for manufacturing the multilayer optical film according to any one of <2> to <4>, A step (1) of kneading a resin containing a polymer containing an alicyclic structure and 2% by weight or more and 7% by weight or less of the fine particles (P) with an extruder including at least two kneading zones to produce a thermoplastic resin composition (B); and A step (2) of forming the first fine particle layer and the second fine particle layer from the thermoplastic resin composition (B); The above step (1) includes a step (1a) of kneading a resin containing the polymer containing the alicyclic structure in a first kneading zone located at the uppermost part of the extruder among the at least two kneading zones, and a step (1b) of supplying the fine particles (P) downstream of the first kneading zone and kneading the resin containing the polymer containing the alicyclic structure and the fine particles (P). A method for manufacturing multilayer optical films. <8> <5> or <6> A method for manufacturing a hard-coated optical film as described above, A step of forming an ultraviolet-curable resin layer on the multilayer optical film; and, The process includes irradiating the resin layer with ultraviolet light to form the hard coat layer; A method for manufacturing hard-coated optical films. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide: a multilayer optical film containing an ultraviolet absorber that has excellent adhesion to a hard coat layer; a hard-coated optical film comprising the multilayer optical film and a hard coat layer, wherein the multilayer optical film and the hard coat layer have excellent adhesion to each other; a method for manufacturing the multilayer optical film; and a method for manufacturing the hard-coated optical film. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing a multilayer optical film according to the first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing a multilayer optical film according to the second embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing a hard-coated optical film according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram showing an example of an extruder used in a method for manufacturing a multilayer optical film according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] 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 appropriate without departing from the scope of the claims and equivalents of the present invention. The components of the embodiments shown below can be combined as appropriate. For example, any numerical value selected from the group of numerical values ​​listed as lower limits and any numerical value selected from the group of numerical values ​​listed as upper limits can be combined as appropriate. Furthermore, in the diagrams, identical components are sometimes denoted by the same reference numeral, and their descriptions may be omitted.

[0011] In the following description, "long film" refers to a film having a length of five times or more its width, preferably 10 times or more its width, and specifically a film long enough to be rolled up for storage or transport. There is no particular upper limit to the length of the film; for example, it may be 100,000 times or less its width.

[0012] In the following explanation, unless otherwise specified, "average primary particle diameter" refers to the particle size at 50% of the integrated value in the particle size distribution determined by dynamic light scattering.

[0013] In the following explanation, the term "(meth)acryloyl" includes "acryloyl," "methacryloyl," and combinations thereof. In the following explanation, the term "(meth)acrylate" includes "acrylate," "methacrylate," and combinations thereof.

[0014] A structural unit formed by polymerizing a monomer is called a "monomer unit," with the name of the monomer followed by "unit." However, the definition of a "monomer unit" is not limited to its formation method. Typically, monomer units are repeating units.

[0015] Unless otherwise specified, "upstream" refers to the upstream direction in which the resin or resin composition is transported.

[0016] In the following explanation, unless otherwise specified, the term "adhesive" includes not only adhesives in the narrow sense (adhesives with a shear storage modulus of 1 MPa to 500 MPa at 23°C after energy ray irradiation or heat treatment) but also adhesives with a shear storage modulus of less than 1 MPa at 23°C. Therefore, the term "adhesive layer" encompasses not only the layer of adhesive in the narrow sense, but also the layer of tack.

[0017] <1. Multilayer optical film> <1.1. First Embodiment of Multilayer Optical Film> The multilayer optical film according to the first embodiment of the present invention is A multilayer optical film comprising a first outer layer, an inner layer, and a second outer layer in this order, The inner layer comprises an ultraviolet absorber and a polymer containing an alicyclic structure. The first outer layer and the second outer layer are each positioned on the outermost surface of the multilayer optical film, have a thickness of 200 nm to 500 nm, contain a polymer including an alicyclic structure, and have a UV absorber content of 0.01% by weight or less. The content R1 of the ultraviolet absorber in the central part of the thickness direction of the inner layer is 1% by weight or more and 20% by weight or less. The percentage (R2 / R1 × 100) of the UV absorber content R2 at a depth of 750 nm in the multilayer optical film relative to the content R1 is 5% or more.

[0018] The multilayer optical film of this embodiment, having the above configuration, exhibits excellent adhesion to the hard coat layer. The reason for this is presumed to be as follows. The hard coat layer can be formed, for example, by forming an ultraviolet-curable resin layer on a multilayer optical film and irradiating the ultraviolet-curable resin layer with ultraviolet light. Multilayer optical films contain ultraviolet absorbers. Since UV absorbers typically generate heat when exposed to ultraviolet light, they can raise the temperature of multilayer optical films. Because the polymerization reaction of polymerizable monomers in the UV-curable resin layer is accelerated at higher temperatures, the curing of the UV-curable resin layer may be accelerated compared to when the multilayer optical film does not contain UV absorbers. If the UV-curable resin layer cures well, the strength of the hard coat layer increases, and the adhesion between the multilayer optical film and the hard coat layer may also improve. It is believed that the higher the content of UV absorbers near the surface of a multilayer optical film, the more the curing of the UV-curable resin layer is accelerated. On the other hand, if the content of UV absorbers near the surface of a multilayer optical film is high, the UV absorbers are more likely to bleed out onto the surface of the multilayer optical film, and as a result, the adhesion between the multilayer optical film and the hard coat layer formed on the surface of the multilayer optical film may decrease. As described above, the multilayer optical film has an outer layer with a thickness of 200 nm to 500 nm and a UV absorber content of 0.01% by weight or less, and the content R1 is 1% by weight or more and 20% by weight or less, and the percentage (R2 / R1 × 100) is 5% or more, thereby balancing the bleed-out of the UV absorber and the curing acceleration effect in the UV-curable resin layer, resulting in excellent adhesion between the hard coat layer and the multilayer optical film.

[0019] A first intermediate layer may be provided between the first outer layer and the inner layer. A second intermediate layer may be provided between the second outer layer and the inner layer.

[0020] Hereafter, the first outer layer and the second outer layer will also be simply referred to as the "outer layer." Similarly, the first medieval layer and the second medieval layer will also be simply referred to as the "medieval layer."

[0021] (Configuration of the first embodiment) Hereinafter, a multilayer optical film according to the first embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 is a schematic cross-sectional view showing a multilayer optical film according to the first embodiment of the present invention. The multilayer optical film 100 comprises an outer layer 110a, an intermediate layer 120a, an inner layer 130, an intermediate layer 120b, and an outer layer 110b in this order in the thickness direction. The outer layer 110a is located on the outermost side of the multilayer optical film 100. The outer layer 110b is located on the outermost side of the multilayer optical film 100. Therefore, the main surface 100U of the multilayer optical film 100 is the surface of the outer layer 110a, and the main surface 100D of the multilayer optical film 100 is the surface of the outer layer 110b.

[0022] In this embodiment, the outer layer 110a and the inner layer 130 are not directly connected, and an intermediate layer 120a is provided between the outer layer 110a and the inner layer 130. The outer layer 110a is provided so as to be directly connected to the intermediate layer 120a, and the inner layer 130 is provided so as to be directly connected to the intermediate layer 120a. Alternatively, the outer layer 110b and the inner layer 130 are not directly connected, and an intermediate layer 120b is provided between the outer layer 110b and the inner layer 130. The outer layer 110b is provided so as to be directly connected to the intermediate layer 120b, and the inner layer 130 is provided so as to be directly connected to the intermediate layer 120b.

[0023] (inner layer) The inner layer 130 contains a polymer including an ultraviolet absorber and an alicyclic structure. The inclusion of the ultraviolet absorber in the inner layer 130 allows the multilayer optical film 100 to have resistance to ultraviolet light. Furthermore, the multilayer optical film 100 can be used as a protective film to protect other optical elements from ultraviolet light. In addition to the ultraviolet absorber and the polymer including the alicyclic structure, the inner layer 130 may contain any other components.

[0024] The ultraviolet absorber contained in the inner layer 130 is not particularly limited. Examples of ultraviolet absorbers contained in the inner layer 130 include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, acrylonitrile-based ultraviolet absorbers, and hydroxyphenyltriazine-based ultraviolet absorbers.

[0025] In particular, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (available from ADEKA as ADEKA stab LA-31), 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]phenol, 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine, etc. are preferably used as UV absorbers.

[0026] The inner layer 130 may contain a single type of ultraviolet absorber, or it may contain two or more types in any arbitrary ratio.

[0027] A polymer containing an alicyclic structure is a polymer that contains an alicyclic structure within its repeating units. Polymers containing an alicyclic structure typically exhibit excellent mechanical strength, transparency, low water absorption, moisture resistance, dimensional stability, and lightweight properties. Polymers containing an alicyclic structure may be amorphous or crystalline.

[0028] Examples of polymers containing alicyclic structures include polymers or their hydrides that can be obtained by polymerization reactions using cyclic olefins as monomers. Furthermore, as polymers containing alicyclic structures, either polymers containing alicyclic structures in the main chain or polymers containing alicyclic structures in the side chains can be used. Among these, polymers containing alicyclic structures are preferably those in which the main chain contains an alicyclic structure. Examples of alicyclic structures include cycloalkane structures and cycloalkene structures, but cycloalkane structures are preferred from the viewpoint of thermal stability and other factors.

[0029] The proportion of repeating units having an alicyclic structure in a polymer containing an alicyclic structure is preferably 30% by weight or more, more preferably 50% by weight or more, even more preferably 70% by weight or more, and particularly preferably 90% by weight or more. By increasing the proportion of repeating units having an alicyclic structure as described above, heat resistance can be improved. Furthermore, in polymers containing alicyclic structures, the remainder other than the repeating units having the alicyclic structure is not particularly limited and can be appropriately selected depending on the intended use.

[0030] Examples of polymers containing alicyclic structures include (1) norbornene polymers, (2) monocyclic olefin polymers, (3) cyclic conjugated diene polymers, (4) vinyl alicyclic hydrocarbon polymers, and their hydrides. Among these, norbornene polymers and their hydrides are preferred from the viewpoint of transparency and moldability.

[0031] Examples of norbornene polymers include ring-opening polymers of monomers having a norbornene structure and their hydrides; and addition polymers of monomers having a norbornene structure and their hydrides. Furthermore, 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 monomers having a norbornene structure and any monomer copolymerizable therewith. Additionally, 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 monomers having a norbornene structure and any monomer copolymerizable therewith. Examples of these polymers include those disclosed in Japanese Patent Application Publication No. 2002-321302, etc. Among these, hydrides of ring-opening monomer polymers having a norbornene structure are particularly preferred from the viewpoint of moldability, heat resistance, low hygroscopicity, low moisture permeability, dimensional stability, and lightweight properties.

[0032] The weight-average molecular weight (Mw) of polymers containing alicyclic structures is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 50,000 or less. Polymers containing alicyclic structures with such weight-average molecular weights exhibit an excellent balance of mechanical strength, moldability, and heat resistance.

[0033] The molecular weight distribution (Mw / Mn) of the polymer containing the alicyclic structure is preferably 1.2 or higher, more preferably 1.5 or higher, particularly preferably 1.8 or higher, preferably 3.5 or lower, more preferably 3.4 or lower, and particularly preferably 3.3 or lower. When the molecular weight distribution is above the lower limit of the above range, the productivity of the polymer containing the alicyclic structure can be increased and manufacturing costs can be suppressed. Furthermore, when it is below the upper limit, the amount of low molecular weight components is reduced, which can improve the stability of the layer containing the polymer containing the alicyclic structure.

[0034] The weight-average molecular weight Mw and number-average molecular weight Mn of polymers containing alicyclic structures can be measured in polyisoprene equivalent values ​​by gel permeation chromatography (GPC) using cyclohexane as the solvent. If the resin does not dissolve in cyclohexane, the values ​​can be measured in polystyrene equivalent values ​​by GPC using toluene as the solvent.

[0035] The glass transition temperature of polymers containing alicyclic structures is preferably 50°C or higher, more preferably 70°C or higher, particularly preferably 80°C or higher, preferably 200°C or lower, more preferably 180°C or lower, and particularly preferably 170°C or lower.

[0036] Specific examples of norbornene polymers and their hydrides include "Zeonor" manufactured by Zeon Corporation; "Arton" manufactured by JSR Corporation; and "TOPAS" manufactured by TOPAS Advanced Polymers.

[0037] The inner layer 130 may contain a polymer containing an alicyclic structure, either alone or in a combination of two or more polymers in any arbitrary ratio.

[0038] From the viewpoint of significantly demonstrating the advantages of the present invention, the proportion of polymers containing alicyclic structures in the inner layer 130 is preferably 80% by weight or more, more preferably 85% by weight or more, even more preferably 90% by weight or more, and preferably 99% by weight or less. Here, the total weight of all components contained in the inner layer 130 is assumed to be 100% by weight.

[0039] The inner layer 130 may contain any components in addition to the UV absorber and the polymer containing the alicyclic structure. Examples of optional components include colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; antistatic agents; antioxidants; surfactants and other compounding agents. The inner layer 130 may contain one of these components alone, or two or more components in any ratio.

[0040] The inner layer 130 has an ultraviolet absorber content R1 in its thickness-direction central portion 131 that is typically 1% by weight or more, preferably 2% by weight or more, more preferably 3% by weight or more, and typically 20% by weight or less, preferably 18% by weight or less, and more preferably 15% by weight or less. Here, the total weight of all components contained in the thickness-direction central portion 131 is assumed to be 100% by weight. When the content R1 is within the aforementioned range, the multilayer optical film 100 can effectively exhibit its ultraviolet absorption ability. Furthermore, the bleed-out of the ultraviolet absorber in the multilayer optical film 100 can be reduced.

[0041] The central portion 131 in the thickness direction of the inner layer 130 is the part of the inner layer 130 that includes a central surface 130C in the thickness direction that is equal in distance from the main surfaces 130U and 130D of the inner layer 130. The central portion 131 in the thickness direction has a main surface 131U and a main surface 131D. The ratio (d131U / d131D) of the distance d131U from the central surface 130C to surface 131U to surface 131D from the central surface 130C is preferably 0.99 / 1.01 or more, preferably 1.01 / 0.99 or less, and ideally 1.00. The thickness of the inner layer 130 at the center in the thickness direction, i.e., the sum of distance d131U and distance d131D, is preferably 19.0 μm or more and 21.0 μm or less, more preferably 19.5 μm or more and 20.5 μm or less, even more preferably 19.8 μm or more and 20.2 μm or less, and most preferably 20.0 μm.

[0042] The UV absorber content R1 in the central part 131 in the thickness direction of the inner layer 130 can be determined, for example, as follows. The surface of the multilayer optical film is removed using a cutting tool such as a microtome to obtain the central portion in the thickness direction of the inner layer. The obtained central portion in the thickness direction of the inner layer is dissolved in a solvent such as cyclohexane, and the absorbance of the resulting solution is measured. The UV absorber concentration in the solution is determined from a pre-prepared calibration curve of UV absorber concentrations, and the UV absorber content R1 in the central portion in the thickness direction of the inner layer is calculated.

[0043] The UV absorber content R1 in the central portion 131 in the thickness direction is typically the same as the UV absorber content in the resin composition used to form the inner layer 130. The content R1 can be adjusted by adjusting the content of the ultraviolet absorber in the resin composition used to form the inner layer 130.

[0044] If the central portion 131 in the thickness direction of the inner layer 130 contains two or more UV absorbers, the content R1 is the sum of the content of the two or more UV absorbers.

[0045] The percentage of the UV absorber content R2 relative to the content R1 (R2 / R1 × 100) is usually 5% or more, preferably 9% or more, and usually 100% or less, preferably 80% or less. Here, the UV absorber content R2 is the UV absorber content at a depth of 750 nm from the surface of the multilayer optical film 100. If two or more UV absorbers are contained in the multilayer optical film 100, the content R2 is the sum of the content of the two or more UV absorbers.

[0046] A percentage (R2 / R1 × 100) being greater than or equal to the lower limit means that when the multilayer optical film 100 is irradiated with ultraviolet light, the multilayer optical film 100 can generate a moderate amount of heat. When the multilayer optical film 100 generates a moderate amount of heat, a hard coat layer with excellent adhesion can be formed on the multilayer optical film 100. Furthermore, if the percentage (R2 / R1 × 100) is less than or equal to the upper limit, it is possible to suppress the bleeding out of the ultraviolet absorber from the surface of the multilayer optical film 100.

[0047] The UV absorber content R2 can be determined, for example, using gas cluster ion beam-time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS) as follows. Using the GCIB-TOF-SIMS method, the intensity of fragment ions originating from the UV absorber is measured from the surface of the multilayer optical film in the depth direction. The intensity of fragment ions originating from the UV absorber at the center 131 of the inner layer 130 is set to 1, and the relative intensity from the surface of the multilayer optical film in the depth direction is calculated. The UV absorber content R1 at the center 131 of the inner layer 130, which was determined separately, and the calculated relative intensity I at a depth of 750 nm from the surface of the multilayer optical film are used. 750 Therefore, the formula is: R2(%) = R1(%) × I 750 It can be determined by this method. The measurement conditions in the GCIB-TOF-SIMS method may be, for example, those described in the Examples section. The content R1 may be determined, for example, by the method described above.

[0048] The content R2 is preferably 0.2% by weight or more, more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less.

[0049] The content R2 can be adjusted by adjusting the content of the ultraviolet absorber in the resin composition for forming the inner layer 130, and by adjusting the thickness of the inner layer 130.

[0050] (outer layer) Outer layer 110a and outer layer 110b are the outermost layers of the multilayer optical film 100, each having a UV absorber content of typically 0.01% by weight or less. Outer layer 110a and / or outer layer 110b may have a UV absorber content of 0.00% by weight, or a UV absorber content greater than 0.00% by weight and 0.01% by weight or less. The UV absorber content in outer layer 110a and the UV absorber content in outer layer 110b may be the same or different from each other. If the outer layer 110a and / or outer layer 110b contains two or more ultraviolet absorbers, the ultraviolet absorber content is the sum of the content of the two or more ultraviolet absorbers, and such sum is usually 0.01% by weight or less.

[0051] If the outer layer 110a and / or outer layer 110b contains an ultraviolet absorber, the ultraviolet absorbers that may be contained in the outer layers 110a and 110b are usually the same as the ultraviolet absorbers contained in the inner layer 130. This is because, during manufacturing, a portion of the ultraviolet absorber contained in the inner layer 130 migrates outward in the thickness direction of the multilayer optical film 100.

[0052] The thickness of the outer layers 110a and 110b is usually 200 nm or more, preferably 250 nm or more, from the viewpoint of suppressing the bleed-out of the ultraviolet absorber and reducing contamination of the film manufacturing equipment, and is usually 500 nm or less, preferably 450 nm or less, from the viewpoint of ensuring good adhesion between the multilayer optical film 100 and the hard coat layer. The thickness of the outer layer 110a and the thickness of the outer layer 110b may be the same or different from each other. From the viewpoint of reducing curling of the multilayer optical film, the ratio of the thickness of the outer layer 110a to the thickness of the outer layer 110b is preferably 0.99 / 1.01 or more, preferably 1.01 / 0.99 or less, and ideally 1.00.

[0053] The thicknesses of the outer layer 110a and outer layer 110b can be measured, for example, as follows. Using the GCIB-TOF-SIMS method, the intensity of fragment ions derived from the UV absorber is measured from the surface of the multilayer optical film in the depth direction. The relative intensity from the surface of the multilayer optical film in the depth direction is calculated, with the intensity of fragment ions derived from the UV absorber in the central part 131 of the inner layer 130 set to 1. From the separately determined UV absorber content R1 in the central part 131 of the inner layer 130 in the thickness direction, the UV absorber content distribution in the thickness direction of the multilayer optical film 100 is determined, with R1 being the content when the relative intensity is 1. From the content distribution, the thickness of the surface layer of the multilayer optical film 100 where the UV absorber content is 0.01% by weight or less is determined, and the determined surface layer thickness of the multilayer optical film 100 can be used as the thickness of the outer layers 110a and 110b.

[0054] The outer layers 110a and 110b contain a polymer including an alicyclic structure and an optional component. The polymers containing alicyclic structures in the outer layers 110a and 110b may be the same as or different from the polymers containing alicyclic structures in the inner layer 130. The polymers containing alicyclic structures in the outer layer 110a and the polymers containing alicyclic structures in the outer layer 110b may be the same as or different from each other.

[0055] Examples of polymers containing alicyclic structures in the outer layer 110a and outer layer 110b are the same examples as the polymers containing alicyclic structures in the inner layer 130 and preferred examples. The outer layer 110a and the outer layer 110b may each contain a polymer containing an alicyclic structure, either individually or in a combination of two or more polymers in any arbitrary ratio.

[0056] From the viewpoint of significantly demonstrating the advantages of the present invention, the proportion of polymers containing alicyclic structures in the outer layers 110a and 110b is preferably 80% by weight or more, more preferably 85% by weight or more, even more preferably 90% by weight or more, and is usually 100% by weight or less, and may be 100% by weight or 99% by weight or less. Here, the total weight of all components contained in the outer layers 110a and 110b is assumed to be 100% by weight.

[0057] The outer layers 110a and 110b may contain optional components other than the UV absorber as an optional component. Examples of optional components include fine particles; colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; antistatic agents; antioxidants; surfactants and other compounding agents. The outer layers 110a and 110b may contain one of these components individually, or two or more components in any ratio. The outer layers 110a and 110b preferably contain fine particles as optional components. The fine particles that may be contained in the outer layers 110a and 110b may be the same as the fine particles contained in the fine particle layer described later.

[0058] (Middle class) The intermediate layer is a layer positioned between the inner layer containing a UV absorber and the outer layer having a UV absorber content of 0.01% by weight or less. Intermediate layers 120a and 120b contain a polymer containing a UV absorber and an alicyclic structure, and the UV absorber content is usually greater than 0.01% by weight. In the intermediate layers 120a and 120b, the content of the ultraviolet absorber gradually decreases toward the outer edge in the thickness direction of the multilayer optical film 100. Therefore, the content of the ultraviolet absorber in the intermediate layers 120a and 120b is usually less than or equal to the content R1 of the ultraviolet absorber in the central part 131 of the inner layer 130 in the thickness direction, preferably less than R1, and therefore usually 20% by weight or less, preferably less than 20% by weight, and usually greater than 0.01% by weight. When the distribution of the ultraviolet absorber content in the intermediate layers 120a and 120b is viewed in the thickness direction, it may have a gradient where it is higher closer to the inner layer 130 and lower further away from the inner layer 130.

[0059] The polymer containing an alicyclic structure in the intermediate layer 120a is usually the same as the polymer containing an alicyclic structure in the outer layer 110a. Similarly, the polymer containing an alicyclic structure in the intermediate layer 120b is usually the same as the polymer containing an alicyclic structure in the outer layer 110b. The polymer containing an alicyclic structure in the intermediate layer 120a and the polymer containing an alicyclic structure in the intermediate layer 120b may be the same as or different from each other.

[0060] <1.2. Second Embodiment of Multilayer Optical Film> The multilayer optical film according to the second embodiment of the present invention comprises a first microparticle layer, the inner layer, and a second microparticle layer in this order. The first fine particle layer includes the first outer layer, The second fine particle layer includes the second outer layer, The first and second fine particle layers each contain a polymer including an alicyclic structure and fine particles (P) in a content of 2% to 7% by weight, the distance between the fine particles (P) is 300 nm to 1000 nm, and the major axis L of the fine particles (P) p The thickness t of the first fine particle layer b1 Ratio to (L p / t b1 ) and the major axis L of the fine particles (P) p The thickness t of the second fine particle layer b2 Ratio to (L p / t b2) is 0.30 or less. Hereinafter, the first particulate layer and the second particulate layer will also be simply referred to as the "particulate layer."

[0061] Preferably, the first fine particle layer further includes a first intermediate layer, the first intermediate layer being disposed between the first outer layer and the inner layer. The second fine particle layer further includes a second intermediate layer, which is positioned between the second outer layer and the inner layer. Preferably, the content of the ultraviolet absorber in the first intermediate layer and the second intermediate layer gradually decreases toward the outer side in the thickness direction of the multilayer optical film.

[0062] (Configuration of the second embodiment) Hereinafter, a multilayer optical film according to a second embodiment of the present invention will be described in detail with reference to the drawings. Figure 2 is a schematic cross-sectional view showing a multilayer optical film according to the second embodiment of the present invention. The multilayer optical film 200 comprises a fine particle layer 240a, an inner layer 130, and a fine particle layer 240b in this order in the thickness direction. The inner layer 130 in the multilayer optical film 200 has a surface 130C and a central portion 131 in the thickness direction, similar to the multilayer optical film 100. The fine particle layer 240a and the fine particle layer 240b are each located on the outermost side in the thickness direction of the multilayer optical film 200.

[0063] The fine particle layer 240a includes the outer layer 210a. The outer layer 210a has the same configuration as the outer layer 110a of the first embodiment, except that it contains fine particles (P). The outer layer 210a is located on the outermost side of the multilayer optical film 200. Therefore, in the fine particle layer 240a, the outer layer 210a is located on the outermost side in the thickness direction. The main surface 200U of the multilayer optical film 200 is the surface of the outer layer 210a. The particulate layer 240a includes an intermediate layer 220a disposed between the outer layer 210a and the inner layer 130. The intermediate layer 220a has the same configuration as the intermediate layer 120a of the first embodiment, except that it contains particulate matter (P). The fine particle layer 240a is provided so as to be in direct contact with the inner layer 130.

[0064] The fine particle layer 240b includes the outer layer 210b. The outer layer 210b has the same configuration as the outer layer 110b of the first embodiment, except that it contains fine particles (P). The outer layer 210b is located on the outermost side of the multilayer optical film 200. Therefore, in the fine particle layer 240b, the outer layer 210b is located on the outermost side in the thickness direction. The main surface 200D of the multilayer optical film 200 is the surface of the outer layer 210b. The particulate layer 240b includes an intermediate layer 220b positioned between the outer layer 210b and the inner layer 130. The intermediate layer 220b has the same configuration as the intermediate layer 120b of the first embodiment, except that it contains particulate matter (P). The fine particle layer 240b is provided so as to be in direct contact with the inner layer 130.

[0065] Some of the UV absorber contained in the inner layer migrates outward in the thickness direction of the multilayer optical film. In particular, migration is accelerated when the temperature of the multilayer optical film is high. If a layer of fine particles containing microparticles is present in the migration path of the UV absorber, the UV absorber is more likely to migrate outward in the thickness direction of the multilayer optical film by traveling along the interface between the microparticles and the resin.

[0066] When the distance between microparticles is large, the number of interfaces between the microparticles and the resin in the microparticle layer decreases, thus reducing the amount of UV absorber that moves along these interfaces. Conversely, when the distance between microparticles is small, the number of interfaces in the microparticle layer increases, thus increasing the amount of UV absorber that moves along these interfaces. Therefore, by keeping the distance between fine particles (P) within an appropriate range, the amount of ultraviolet absorber that moves from the inner layer outward in the thickness direction of the multilayer optical film can be controlled, and as a result, the thickness of the outer layer of the multilayer optical film, in which the ultraviolet absorber content is 0.01% by weight or less, can be controlled.

[0067] The distance between fine particles (P) is preferably 300 nm or more from the viewpoint of reducing bleed-out of the ultraviolet absorber, and preferably 1000 nm or less, more preferably 800 nm or less, even more preferably 750 nm or less, and even more preferably 550 nm or less from the viewpoint of forming a hard coat layer with good adhesion on the multilayer optical film due to the heat generated by the ultraviolet absorber when irradiated with ultraviolet light.

[0068] The distance between particles (P) can be measured, for example, by the following method. A cross-section of a multilayer optical film, including its thickness, is observed using a scanning electron microscope. The distance between a given particle and the nearest particle is measured and defined as the shortest distance. For 10 particles within the observation field, the shortest distance is measured, and the longest distance among these 10 points is defined as the distance between particles. The scanning electron microscope can be set to a magnification of 10,000x, and the size of the observation field can be 12 μm × 9 μm. If the observation field includes secondary particles formed by the aggregation of primary particles, the secondary particles can be treated as a single particle, and the shortest distance can be measured to determine the maximum distance.

[0069] The distance between particles (P) can be adjusted, for example, by the following method. A section of the multilayer optical film is cut from the center in the width direction, and the cross-section including the thickness direction of the multilayer optical film is observed using a scanning electron microscope (for example, JEOL Ltd.'s "JSM-7401F"). The magnification is 10,000x, and the size of the observation field is 12 μm × 9 μm. The distance between a given particle and the particle closest to it is measured and recorded as the shortest distance. For 10 particles in the observation field, the shortest distance is measured, and the longest distance among these 10 shortest distances can be used as the distance between microparticles.

[0070] By increasing the content of fine particles (P) in the resin composition for forming the fine particle layer, the distance between the fine particles (P) can be reduced. By reducing the proportion of aggregated microparticles (P) within the microparticle layer, the distance between microparticles (P) can be reduced.

[0071] As described above, ultraviolet absorbers tend to move outward in the thickness direction of the multilayer optical film by traveling along the interface between the microparticles and the resin. The smaller the major axis of the microparticles, the smaller the interface between the microparticles and the resin, and therefore the less ultraviolet absorber moves along this interface. Conversely, the larger the major axis of the microparticles, the larger the interface becomes, and therefore the more ultraviolet absorber moves along this interface. On the other hand, the greater the thickness of the microparticle layer, the less likely it is that the UV absorber moving from the inner layer outward in the thickness direction of the multilayer optical film will reach the surface of the multilayer optical film. Conversely, the smaller the thickness of the microparticle layer, the easier it is for the UV absorber to reach the surface of the multilayer optical film from the inner layer. Therefore, the major axis L of the fine particles (P) P By setting the ratio of the microparticle layer to an appropriate value or less, the amount of ultraviolet absorber that moves from the inner layer outward in the thickness direction of the multilayer optical film can be controlled, and as a result, the thickness of the outer layer of the multilayer optical film, in which the ultraviolet absorber content is 0.01% by weight or less, can be controlled.

[0072] Longest axis L of the fine particles (P) p The thickness t of the first fine particle layer b1 Ratio to (L p / t b1 ) and the major axis L of the fine particles (P) p The thickness t of the second fine particle layer b2 Ratio to (L p / t b2 The value of the UV absorber is preferably 0.30 or less, more preferably 0.25 or less, and even more preferably 0.20 or less, from the viewpoint of reducing bleed-out of the UV absorber, and is usually greater than 0.00, and is preferably 0.01 or more from the viewpoint of forming a hard coat layer with good adhesion on the multilayer optical film by generating heat in the UV absorber when irradiated with ultraviolet light.

[0073] Ratio (L p / t b1 ) and ratio (L p / t b2 These values ​​may be the same or they may be different.

[0074] The major axis of the fine particles (P) is preferably 0.05 μm or more, more preferably 0.1 μm or more, from the viewpoint of increasing the thickness of the outer layer, and preferably 2 μm or less, more preferably 1 μm or less, from the viewpoint of improving the slipperiness of the multilayer optical film and improving the quality of the wound body.

[0075] Longest axis L of the fine particles (P) P This can be measured, for example, by the following method. The central portion of the multilayer optical film in the width direction is cut out, and the cross-section including the thickness direction of the multilayer optical film is observed using a scanning electron microscope (e.g., JEOL Ltd. "JSM-7401F"). The magnification is 10,000x, and the size of the observation field is 12 μm × 9 μm. The major axes of any 10 particles in the observation field are measured, and the average of these measurements can be used as the major axis of the microparticle. If the fine particles (P) include secondary particles formed by the aggregation of primary particles, the secondary particles are considered as the aforementioned particles, and the major axis L of the fine particles (P) P Measure.

[0076] Since fine particles with various average particle sizes are commercially available, the desired major axis L P Fine particles having the properties can be obtained from the market and used as fine particles (P). Furthermore, by thoroughly dispersing the fine particles (P) in the resin, the aggregation of primary particles is reduced, and the major axis L of the fine particles (P) P It can be made smaller.

[0077] Thickness t of the first microparticle layer b1 and the thickness t of the second fine particle layer b2 This can be measured, for example, by the following method. A multilayer optical film was sliced ​​to a thickness of 0.05 μm using a microtome (for example, "RV-420" manufactured by Yamato Koki Co., Ltd.), and the cross-section was observed under a microscope to determine the thickness t. b1 and thickness t b2 It can be measured.

[0078] thickness t b1 and thickness t b2The particle size is preferably 1.0 μm or more, more preferably 1.5 μm or more, preferably 5.0 μm or less, and more preferably 4.0 μm or less.

[0079] thickness t b1 and thickness t b2 This may be the same or different. From the viewpoint of reducing curling of multilayer optical films, the thickness t b1 Thickness t b2 The ratio to is preferably 0.99 / 1.01 or higher, preferably 1.01 / 0.99 or lower, and ideally 1.00.

[0080] The particulate layers 240a and 240b each contain fine particles (P), a polymer containing an alicyclic structure, and an optional component. The particulate layers 240a and 240b may also contain an ultraviolet absorber. The polymers containing alicyclic structures in the fine particle layers 240a and 240b may be the same as or different from the polymers containing alicyclic structures in the inner layer 130. The polymers containing alicyclic structures in the fine particle layer 240a and the polymers containing alicyclic structures in the fine particle layer 240b may be the same as or different from each other.

[0081] Examples of polymers containing alicyclic structures included in each of the fine particle layers 240a and 240b include the same examples as those included in the inner layer 130 and preferred examples. Each of the fine particle layers 240a and 240b may contain one type of polymer containing an alicyclic structure, or it may contain two or more types in any arbitrary ratio.

[0082] From the viewpoint of significantly demonstrating the advantages of the present invention, the proportion of polymers containing alicyclic structures in the fine particle layers 240a and 240b is preferably 80% by weight or more, more preferably 85% by weight or more, even more preferably 90% by weight or more, and even more preferably 93% by weight or more, and is usually 100% by weight or less, and may be 98% by weight or less. Here, the total weight of all components contained in the fine particle layers 240a and 240b is taken as 100% by weight.

[0083] The fine particles (P) contained in the fine particle layers 240a and 240b may be inorganic particles, organic particles, or composite particles combining inorganic and organic materials. The fine particle layers 240a and 240b may contain fine particles (P) of one type alone, or in any combination of two or more types in any ratio. As for fine particles, particles with various average primary particle sizes are commercially available and can be used.

[0084] The average primary particle diameter of the fine particles (P) is preferably 0.10 μm or more, more preferably 0.20 μm or more, and even more preferably 0.30 μm or more, from the viewpoint of improving the slipperiness of the multilayer optical film and improving the quality of the wound body, and preferably 0.80 μm or less, more preferably 0.50 μm or less, and even more preferably 0.40 μm or less, from the viewpoint of reducing the bleed-out of the ultraviolet absorber.

[0085] The average primary particle size of fine particles (P) can be measured using a particle size analyzer based on dynamic light scattering. Specifically, a multilayer optical film is dissolved using a suitable solvent. The insoluble portion contains fine particles, while the resin is contained in the soluble portion. By removing the soluble portion, the fine particles (P) are recovered, and an aqueous slurry with a particle concentration of 2% by weight is prepared. The particle size distribution is then measured using a particle size distribution analyzer that employs dynamic light scattering (for example, Otsuka Electronics' "multi-sample nanoparticle size measurement system nanoSAQLA"). The particle size at 50% of the cumulative value in this particle size distribution can be used as the average primary particle size of the fine particles (P).

[0086] Preferably, the fine particles (P) are those in which the weight of fine particles (P) is reduced by W2 when weight W1 of fine particles (P) is increased from 40°C to 550°C at a rate of 10°C / min, and the weight reduction rate expressed by the following formula is 1% or less. Weight reduction rate (%)=W2 / W1×100 The weight loss rate is usually 0% or more, and ideally 0%. A weight loss rate of 1% or less for fine particles (P) can improve the heat resistance of multilayer optical films and effectively reduce contamination of manufacturing equipment for multilayer optical films.

[0087] The fine particles (P) may be inorganic particles as described above. Examples of inorganic particles include silica particles, synthetic zeolite particles, and glass particles. From the viewpoint of achieving a uniform particle size distribution, the fine particles (P) are preferably silica particles. Examples of commercially available silica particles include the "QSG" series from Shin-Etsu Chemical Co., Ltd., the "SeaHostar" series from Nippon Shokubai Co., Ltd., and the "AdmaFine" series from Admatex Co., Ltd.

[0088] The fine particles (P) may be organic particles as described above. An example of organic particles is polymethyl methacrylate crosslinked particles. Polymethyl methacrylate crosslinked particles refer to particles composed of a crosslinked polymer containing methyl methacrylate monomer units. An example of organic particles is "Epostor MX" manufactured by Nippon Shokubai Co., Ltd.

[0089] The content of fine particles (P) in the fine particle layer 240a and the content of fine particles (P) in the fine particle layer 240b is preferably 2% by weight or more, more preferably 3% by weight or more, and preferably 7% by weight or less, from the viewpoint of improving the slipperiness of the multilayer optical film and reducing the bleed-out of the ultraviolet absorber.

[0090] The UV absorbers that may be included in the fine particle layers 240a and 240b are the same as the UV absorbers that are normally included in the inner layer 130. In the fine particle layers 240a and 240b, the content of the ultraviolet absorber gradually decreases towards the outer edge in the thickness direction of the multilayer optical film 300.

[0091] <1.3. Characteristics of Multilayer Optical Films> The multilayer optical film may be an unstretched film or a stretched film. It is preferable that the multilayer optical film be an unstretched film.

[0092] Multilayer optical films may be surface-treated. Examples of surface treatments include corona discharge treatment and plasma discharge treatment. Surface treatment can improve the adhesion between the multilayer optical film and functional layers such as hard coat layers.

[0093] The thickness of the multilayer optical film can be set to any thickness, but is preferably 10 μm or more, more preferably 30 μm or more, preferably 100 μm or less, and more preferably 90 μm or less.

[0094] It is preferable that the multilayer optical film has excellent slipperiness. Slipperiness can be evaluated by using a friction tester to determine the static friction coefficient between the films in accordance with JIS K7125, with a load of 1 kgf. The static friction coefficient of the multilayer optical film, as determined by the method described in the Examples section, is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.7 or less, and preferably 0.4 or more.

[0095] If the static friction coefficient of the film, measured under a load of 1 kgf, is above the lower limit, the film's slipperiness can be made appropriate, resulting in improved handling during film winding. Furthermore, if the static friction coefficient of the film, measured under a load of 1 kgf, is below the upper limit, blocking near the core when a long length of multilayer optical film is rolled can be reduced, thereby reducing the occurrence of defects such as scratches.

[0096] The haze of the multilayer optical film is preferably 2.0% or less, more preferably 1.5% or less, usually 0.0% or more, and ideally 0.0%. The internal haze of the multilayer optical film is preferably 0.5% or less, usually 0.0% or more, and ideally 0.0%. Due to the low haze and internal haze of the multilayer optical film, it can be suitably used as a component of image display devices that require high-resolution display performance. The haze and internal haze of the multilayer optical film can be measured using a haze meter.

[0097] <1.4. Applications of Multilayer Optical Films> Multilayer optical films can be suitably used as protective films to protect any optical element (e.g., a polarizer) from ultraviolet light by combining them with any optical element. Furthermore, the multilayer optical film can be suitably used as a base film for manufacturing a hard-coated optical film that includes a hard-coat layer.

[0098] <2. Hard-coated optical film> A hard-coated optical film according to one embodiment of the present invention includes the multilayer optical film and a hard-coated layer provided on the multilayer optical film. Figure 3 is a schematic cross-sectional view showing a hard-coated optical film according to one embodiment of the present invention. As shown in Figure 3, the hard coat optical film 300 comprises a hard coat layer 310 provided on one surface 100U of the multilayer optical film 100. The hard coat layer 310 is provided so as to be directly on the surface 100U of the multilayer optical film 100. In other words, there is no layer interposed between the multilayer optical film 100 and the hard coat layer 310.

[0099] In another embodiment, a hard coat layer 310 may be provided on both surface 100U and surface 100D of the multilayer optical film 100. In another embodiment, the hard coat optical film may be a film including the multilayer optical film 200 according to the second embodiment and a hard coat layer provided on one surface 200U of the multilayer optical film 200. Alternatively, the hard coat layer 310 may be provided on both surface 200U and surface 200D of the multilayer optical film 200.

[0100] The hard coat layer is a layer with high hardness. By incorporating a hard coat layer, the surface of the hard coat optical film can be reduced. The hardness of the hard coat layer can be expressed using the JIS pencil hardness scale. 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 optical film can be improved. Here, JIS pencil hardness is defined in accordance with JIS K5600-5-4, where pencils of various hardnesses are tilted at a 45° angle, a 500g load is applied from above, and the surface of the layer is scratched, indicating the hardness of the pencil at which scratches begin to appear.

[0101] Such hard coat layers are typically made of a resin containing a polymer. Any polymer can be used as the polymer in the hard coat layer, as long as it is within the range that a hard coat layer with the desired hardness can be obtained.

[0102] The amount of polymer in the hard coat layer is preferably 50% by weight or more, more preferably 60% by weight or more, particularly preferably 70% by weight or more, preferably 100% by weight or less, more preferably 95% by weight or less, and particularly preferably 90% by weight or less. By setting the amount of polymer within the above range, the adhesion between the hard coat layer and the multilayer optical film can be effectively improved.

[0103] The hard coat layer may contain any components in addition to the polymer, as needed. For example, the hard coat layer may contain metal oxide particles. The hard coat layer may contain any one component alone, or two or more components in any combination of proportions.

[0104] The thickness of the hard coat layer is preferably 1.5 μm or more, more preferably 2.0 μm or more, even more preferably 3.0 μm or more, preferably 10.0 μm or less, more preferably 8.0 μm or less, and even more preferably 7.0 μm or less. By keeping the thickness of the hard coat layer within the above range, curling of the hard coat optical film can be reduced. Furthermore, the scratch resistance of the hard coat layer can be improved.

[0105] As the hard coat layer, for example, the hard coat layer described in Japanese Patent Publication No. 2016-157068 can be used.

[0106] A hard-coated optical film may have any additional layers in combination with a multilayer optical film and a hard-coat layer. Examples of such additional layers include an anti-reflective layer, an adhesive layer, an easy-adhesion layer to enhance adhesion, and an antistatic layer.

[0107] The hard coat layer may be a layer formed by curing a UV-curable resin layer. The UV-curable resin layer used to form the hard coat layer will be described later.

[0108] <3. Method for manufacturing multilayer optical films> The multilayer optical film can be manufactured by any method. For example, a multilayer optical film can be manufactured by a method that includes: forming the inner layer with a thermoplastic resin composition (A) containing an ultraviolet absorber and a polymer containing an alicyclic structure; and forming layers located outside the inner layer in the thickness direction of the multilayer optical film (the outer layer and intermediate layer in the first embodiment, and the fine particle layer in the second embodiment) with a thermoplastic resin composition (B) containing a polymer containing an alicyclic structure and having an ultraviolet absorber content of 0.01% by weight or less. The layers of a multilayer optical film can be formed, for example, by a melt co-extrusion method in which a molten layer of thermoplastic resin composition (A) and a molten layer of thermoplastic resin composition (B) are superimposed and co-extruded. By heating the resin composition for forming each layer of a multilayer optical film to a temperature above the glass transition temperature of the resin composition and extruding it in layers, a portion of the ultraviolet absorber contained in the thermoplastic resin composition (A) moves outward in the thickness direction of the multilayer optical film, forming an intermediate layer in which the amount of ultraviolet absorber gradually decreases outward in the thickness direction.

[0109] For example, the multilayer optical film according to the second embodiment described above can be manufactured by a method including the following steps (1) and (2). Step (1): A step of producing a thermoplastic resin composition (B) by kneading a resin containing a polymer including an alicyclic structure and the fine particles (P) in an extruder having at least two kneading zones. Step (1) includes a step (1a) of kneading a resin containing the polymer containing the alicyclic structure in a first kneading zone located at the uppermost part of the extruder among the at least two kneading zones; and a step (1b) of supplying the fine particles (P) downstream of the first kneading zone and kneading the resin containing the polymer containing the alicyclic structure and the fine particles (P). Step (2): A step of forming the first fine particle layer and the second fine particle layer from the thermoplastic resin composition (B). Process (1) and process (2) are usually carried out in this order. The method for manufacturing a multilayer optical film may include any additional steps in addition to steps (1) and (2) described above.

[0110] <3.1. Process (1)> Step (1) is a step in which a thermoplastic resin composition (B) is manufactured. The thermoplastic resin composition (B) comprises a resin containing a polymer with an alicyclic structure and fine particles (P). Since the thermoplastic resin composition (B) is a composition for forming the first and second fine particle layers, the polymer containing an alicyclic structure contained in the thermoplastic resin composition (B) is usually the same as the polymer containing an alicyclic structure that may be contained in the first and second fine particle layers. Also, the fine particles (P) contained in the thermoplastic resin composition (B) are usually the same as the fine particles (P) contained in the first and second fine particle layers.

[0111] Thermoplastic resin composition (B) typically contains 0.01% by weight or less of ultraviolet absorbers, and is usually 0.00% by weight or greater than 0.00% by weight. Here, the total amount of all components contained in thermoplastic resin composition (B) is assumed to be 100% by weight. By ensuring that the content of the ultraviolet absorber in the thermoplastic resin composition (B) is below the upper limit, the content of the ultraviolet absorber in the outer layer of the multilayer optical film can be 0.01% by weight or less.

[0112] A resin containing a polymer with an alicyclic structure may also contain optional components in addition to the polymer containing the alicyclic structure. Examples of arbitrary components include those listed as possible components that may be included in the outer layer. A resin containing a polymer with an alicyclic structure may contain any one component alone, or two or more components in any combination of proportions.

[0113] The content of fine particles (P) in the thermoplastic resin composition (B) is preferably 2% by weight or more, more preferably 3% by weight or more, and preferably 7% by weight or less, from the viewpoint of improving the slipperiness of the multilayer optical film and reducing the bleed-out of the ultraviolet absorber. Here, the total amount of all components contained in the thermoplastic resin composition (B) is assumed to be 100% by weight.

[0114] The kneading in step (1) is carried out in an extruder having at least two kneading zones. Examples of extruders include single-screw extruders, twin-screw extruders, and multi-screw extruders with three or more shafts. In this embodiment, a twin-screw extruder is preferred because it allows for good kneading of the resin and fine particles, and facilitates the easy production of the thermoplastic resin composition (B) described above. According to step (1) in this embodiment, since the mixing is carried out well, chemical and physical changes of the fine particles (P) (e.g., pulverization of fine particles (P), bonding of fine particles (P)) are unlikely to occur. Therefore, it is considered that the size of the fine particles (P) does not change easily due to mixing, and consequently, the particle size distribution of the fine particles (P) does not change easily before and after mixing. Thus, the average primary particle diameter of the fine particles (P) that may be contained in the multilayer optical film is approximately the same as the average primary particle diameter of the fine particles (P) before mixing.

[0115] Figure 4 is a schematic diagram showing an example of an extruder used in a method for manufacturing a multilayer optical film according to one embodiment of the present invention. Figure 4 shows an example of an extruder used in step (1), and schematically shows a cross-section of the extruder including the screw shaft. In Figure 4, the extruder 1000 is a twin-screw extruder equipped with two screws, but only one of the two screws is shown, with the other screw omitted. The extruder 1000 comprises a cylinder 1100 and a screw 1200 housed within the cylinder 1100.

[0116] The cylinder 1100 comprises a wall portion 1110, a kneading chamber 1120 capable of kneading resin and particles, a resin supply port 1130 for supplying resin to the kneading chamber 1120, a particle supply port 1140 for supplying fine particles, a vent port 1150 for discharging gas from the kneading chamber 1120 to the outside, and a discharge port 1160 for discharging the resin composition. Typically, the cylinder 1100 is equipped with the resin supply port 1130, the particle supply port 1140, the vent port 1150, and the discharge port 1160 in this order from the upstream side in the axial direction of the screw. In the following description, unless otherwise specified, "axial direction" refers to the axial direction of the screw.

[0117] The kneading chamber 1120 is a hollow section formed inside the cylinder 1100 to allow kneading of resin and fine particles within the cylinder 1100. The kneading chamber 1120 is typically provided to extend in the axial direction, and the screw 1200 is housed within this kneading chamber 1120.

[0118] The resin supply port 1130 is a hole formed to supply resin to the kneading chamber 1120. The fine particle supply port 1140 is a hole formed to supply fine particles to the kneading chamber 1120. Typically, the resin supply port 1130 and the fine particle supply port 1140 are formed in the wall portion 1110 of the cylinder 1100, penetrating this wall portion 1110. Typically, the fine particle supply port 1140 is located on the discharge side of the cylinder, closer to the resin supply port 1130. A feeder is usually connected to the resin supply port 1130 and the fine particle supply port 1140, and the resin and fine particles are supplied to the kneading chamber of the cylinder through the feeder.

[0119] The vent port 1150 is a hole provided to allow gas generated inside the cylinder to be discharged to the outside. Typically, it is formed in the wall portion 1110 of the cylinder 1100 so as to penetrate the wall portion 1110. There may be multiple vent ports 1150 provided in the cylinder 1100, but it is preferable to have only one. A pressure reducing device is usually connected to the vent port.

[0120] The vent port in the cylinder is located closer to the discharge port than the mixing zone, which will be described later.

[0121] The discharge port 1160 is a hole formed to allow the thermoplastic resin composition obtained in the kneading chamber 1120 to be discharged outside the cylinder 1100. Typically, the discharge port 1160 is formed at one axial end of the cylinder 110.

[0122] The screw 1200 comprises a conveying element 1210 and a kneading element 1220 as screw elements. As the conveying element 1210, for example, a full-flight screw element having a relatively recessed groove and a relatively protruding flight portion may be used. As the kneading element 1220, for example, a kneading disc may be used. The screw elements are mounted on the screw shaft 1230 and are usually mounted extending in the axial direction. The screw 1200 is rotatably supported by a bearing (not shown) formed at the other axial end of the cylinder 1100 (the end opposite to the discharge port 1160). The screw 1200 is also connected to a drive device (not shown) for supplying power to rotate the screw 1200 in the circumferential direction.

[0123] In a screw, the mixing element is typically located only in the mixing zone (described later) in the axial direction of the cylinder, while the conveying element is located in the conveying zone other than the mixing zone in the axial direction of the cylinder.

[0124] The combination of the two screws 1200 in a twin-screw extruder may be a fully meshed type, an incompletely meshed type, or a non-meshing type. Among these, the fully meshed type is preferred because it provides good mixing performance. Furthermore, the rotation directions of the multiple screws 1200 may be the same direction or different directions.

[0125] In this embodiment, the cylinder 1100 of the extruder 1000 is divided into several sections in its axial direction, depending on the type of screw element of the screw arranged within the cylinder 1100. The cylinder 1100 typically has at least two kneading zones in its axial direction. In this embodiment, the cylinder 1100 of the extruder 1000 comprises, in order from the axial upstream of the cylinder 1100, kneading zone 1301 as the first kneading zone, kneading zone 1302, and kneading zone 1303.

[0126] Mixing zones 1301, 1302, and 1303 are sections where the mixing elements of the screw are located. In this embodiment, three mixing zones are provided in the cylinder, but in another embodiment, at least two mixing zones may be provided, for example, two or four or more, and preferably two or three. In the mixing zones, the resin and fine particles are mixed by the action of the mixing elements, and the mixed material is usually conveyed downstream.

[0127] Typically, a conveying zone is provided upstream and downstream of the mixing zone, as well as between the mixing zones, where conveying elements are located. In the conveying zone, the mixing of resin and fine particles by the mixing elements is paused, however, for example, the mixing of resin and fine particles may continue due to the action of the conveying elements. In this embodiment, a conveying zone 1401 is provided upstream of the kneading zone 1301, a conveying zone 1404 is provided downstream of the kneading zone 1303, and a conveying zone 1402 and a kneading zone 1403 are provided between the kneading zone 1301 and the kneading zone 1302, and between the kneading zone 1302 and the kneading zone 1303, respectively.

[0128] The multiple mixing zones may have the same length or different lengths in the axial direction of the screw. The multiple conveying zones may have the same or different lengths in the axial direction of the screw.

[0129] Using the extruder 1000 configured as described above, step (1) is carried out, for example, as follows. Using an extruder 1000, a resin containing a polymer with an alicyclic structure and fine particles (P) are kneaded. The content of fine particles (P) in the kneaded resin and fine particles (P) is usually 2% by weight or more, preferably 3% by weight or more, and usually 7% by weight or less, based on the total of the resin containing the polymer with an alicyclic structure and the fine particles (P) being 100% by weight. It is preferable to adjust the content of the fine particles (P) to be kneaded so that the content of fine particles (P) in the fine particle layer falls within the above-mentioned preferred range. In one example, the content of fine particles (P) in the fine particle layer is equal to the content of the fine particles (P) to be kneaded.

[0130] In this embodiment, step (1) includes step (1a) of kneading a resin containing the polymer including the alicyclic structure in kneading zone 1301, which is the first kneading zone located at the uppermost position of the extruder 1000 among the at least two kneading zones 1301, 1302, and 1303. In this embodiment, resin is supplied from the resin supply port 1130 to the conveying zone 1401 located upstream of the kneading zone 1301. The resin is then conveyed to the kneading zone 1301, where it is kneaded.

[0131] In this embodiment, step (1) includes step (1b) of supplying the fine particles (P) downstream of the kneading zone 1301 as the first kneading zone and kneading the resin containing the polymer including the alicyclic structure and the fine particles (P). In this embodiment, fine particles (P) are supplied from the fine particle supply port 1140 to the conveying zone 1402, which is downstream of the kneading zone 1301. Preferably, the fine particles (P) are supplied downstream of the first kneading zone and upstream of at least one kneading zone. Therefore, in another embodiment, fine particles (P) may be supplied to the conveying zone 1403, which is downstream of the kneading zone 1301 and upstream of the kneading zone 1303.

[0132] The resin and fine particles (P) containing polymers with alicyclic structures are mixed in mixing zone 1302 and mixing zone 1303, transported downstream in conveying zone 1404, and discharged from discharge port 1160. In conveying zone 1404, gas is discharged from vent port 1150.

[0133] The average primary particle diameter of the fine particles (P) supplied in step (1b) is preferably 0.10 μm or more, more preferably 0.20 μm or more, and even more preferably 0.30 μm or more, from the viewpoint of improving the slipperiness of the multilayer optical film and improving the quality of the wound body, and preferably 0.80 μm or less, more preferably 0.50 μm or less, and even more preferably 0.40 μm or less, from the viewpoint of reducing the bleed-out of the ultraviolet absorber. The average primary particle diameter can be defined as the particle size at which the cumulative value of the particle size distribution is 50% when a water slurry with a particle concentration of 2 wt% is prepared and measured using a particle size distribution analyzer that employs dynamic light scattering (for example, Otsuka Electronics' "multi-sample nanoparticle size measurement system nanoSAQLA").

[0134] The manufacturing method of this embodiment, by including steps (1a) and (1b), generally has the following advantages. The resin containing a polymer with an alicyclic structure, supplied to the extruder, is kneaded in the first kneading zone before being kneaded with fine particles (P). Therefore, the resin is sufficiently plasticized when it is kneaded with the fine particles (P). Furthermore, the fine particles (P) are supplied downstream of the first mixing zone. Therefore, the fine particles (P) can be well dispersed in the resin that has been plasticized in the first mixing zone. As a result, in the obtained thermoplastic resin composition (B), aggregation of fine particles (P) is reduced, and the ratio (L) p / t b1 ) and ratio (L p / t b2 Control of the ratio (L) becomes easier. The more the aggregation of fine particles (P) is reduced, the easier it is to control the ratio (L). p / t b1 ) and ratio (L p / t b2 ) can be made smaller.

[0135] <3.2. Process (2)> Step (2) is a step of forming the first fine particle layer and the second fine particle layer from the thermoplastic resin composition (B). A melt extrusion method is preferred as the method for forming the first and second fine particle layers from the thermoplastic resin composition (B). In particular, it is preferable to form the first fine particle layer, the inner layer, and the second fine particle layer by melt co-extrusion. The formation of each layer by melt co-extrusion preferably includes a step of extruding in layers a molten thermoplastic resin composition (A) for forming the inner layer and a molten thermoplastic resin composition (B) for forming the fine particle layer.

[0136] Examples of molding methods by co-extrusion include the co-extrusion T-die method, the co-extrusion inflation method, and the co-extrusion lamination method, with the co-extrusion T-die method being preferred. Examples of the co-extrusion T-die method include the feed block method and the multi-manifold method, with the feed block method being preferred because it simplifies the equipment configuration.

[0137] <3.3. Optional Steps> Examples of optional steps that may be included in addition to steps (1) and (2) above include the steps of heating and melting the thermoplastic resin composition (A) and / or (B) and supplying them to an extrusion molding machine, cooling the molten thermoplastic resin composition (A) and the molten thermoplastic resin composition (B) that have been extruded in layers, winding a long multilayer optical film into a roll, and stretching the multilayer optical film.

[0138] <4. Method for manufacturing hard-coated optical films> Hard-coated optical films can be manufactured by any method. A hard-coated optical film can preferably be manufactured by a manufacturing method that includes the following steps in this order. A step of forming an ultraviolet-curable resin layer on the multilayer optical film. A step of irradiating the resin layer with ultraviolet light to form the hard coat layer.

[0139] The method for manufacturing a hard-coated optical film may include a step of manufacturing a multilayer optical film before the step of forming an ultraviolet-curable resin layer. Examples of the process for manufacturing a multilayer optical film include the examples given as methods for manufacturing a multilayer optical film, and preferably include steps (1) and (2).

[0140] The formation of the UV-curable resin layer is preferably carried out by a process that includes applying a liquid composition containing a UV-curable resin onto a multilayer optical film to form a film of the liquid composition. The formation of the resin layer may also include a step of drying the film of the liquid composition as needed.

[0141] The liquid composition typically contains an ultraviolet-curable resin. UV-curable resins are resins that harden when exposed to ultraviolet light. UV-curable resins typically contain materials with polymerizable groups. UV-curable resins may contain monomers containing polymerizable groups, oligomers containing polymerizable groups, or polymers containing polymerizable groups. Hereinafter, monomers containing polymerizable groups will also be referred to as polymerizable monomers.

[0142] As materials containing polymerizable groups that may be included in UV-curable resins, any material can be used within the range that yields a hard coat layer with the desired hardness. In particular, UV-curable resins preferably contain polymerizable monomers as materials containing polymerizable groups, and more preferably contain polymerizable monomers having three or more (meth)acryloyl groups per molecule. UV-curable resins preferably contain 50% by weight or more of polymerizable monomers 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. By using a UV-curable resin containing such polymerizable monomers, the hardness of the hard coat layer can be increased.

[0143] 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.

[0144] As polymerizable monomers, compounds having three or more (meth)acryloyl groups in one molecule may be used individually 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.

[0145] In particular, the UV-curable resin preferably contains, with a total of 80% by weight or more of compounds having 4 (meth)acryloyl groups, compounds having 5 (meth)acryloyl groups, and compounds having 6 (meth)acryloyl groups per molecule, with the total polymerizable monomers in the UV-curable resin being 100% by weight.

[0146] Furthermore, as polymerizable monomers, any monomeric compound may be used in combination with a compound having three or more (meth)acryloyl groups in one molecule, as described above. Examples of arbitrary monomeric compounds 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 allyl groups, such as allyl methacrylate, diallyl phthalate, and glycerin diallyl ether; bisphenoxyethanol fluororange acrylate, 2-propenoic acid [5,5'-(9-fluorene-9-ylidene)bis(1,1'-biphenyl)-2-(polyoxyethylene) ester], 2 Examples include 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]; 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; and so on. These may be used individually or in combination of two or more in any ratio.

[0147] Materials containing the aforementioned polymerizable groups can usually be polymerized by irradiation with active energy rays such as ultraviolet light. Therefore, it is preferable that UV-curable resins contain a photopolymerization initiator in addition to the material containing the polymerizable groups.

[0148] Examples of photopolymerization initiators include benzoin derivatives, benzyl ketals, α-hydroxyacetophenones, α-aminoacetophenones, acylphosphine oxides, and o-acyloximes. A single photopolymerization initiator may be used alone, or two or more may be used in any ratio.

[0149] The amount of 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, preferably 20 parts by weight or less, more preferably 10 parts by weight or less, particularly preferably 5 parts by weight or less, per 100 parts by weight of polymerizable monomer.

[0150] UV-curable resins may contain, in addition to materials containing polymerizable groups, any other components as needed. Examples of optional components that UV-curable resins may contain include metal oxide nanoparticles. These optional components may be used individually or in combination of two or more components in any ratio.

[0151] A liquid composition for forming an ultraviolet-curable resin layer may contain a solvent. Preferably, the solvent is capable of dissolving the ultraviolet-curable resin and is readily volatile. 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. Furthermore, the solvent may be used alone, or two or more solvents may be used in any ratio.

[0152] After preparing the liquid composition, this liquid composition is applied onto a multilayer optical film to form a film of the liquid composition on the multilayer optical film. Examples of application methods include bar coating, slot coating, spin coating, roll coating, curtain coating, and screen printing.

[0153] After coating the liquid composition onto a multilayer optical film, the solvent is removed from the film of the liquid composition by drying, if necessary. By following the above procedure, an ultraviolet-curable resin layer can be formed on a multilayer optical film.

[0154] Next, the UV-curable resin layer is irradiated with ultraviolet light to form a hard coat layer. The manufacturing method of this embodiment makes it possible to produce a hard-coated optical film with high adhesion between the multilayer optical film and the hard-coat layer. By using the aforementioned multilayer optical film as the multilayer optical film, the bleed-out effect of the UV absorber and the curing acceleration effect in the UV-curable resin layer are balanced, making it possible to obtain a hard-coated optical film with excellent adhesion between the hard coat layer and the multilayer optical film. [Examples]

[0155] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0156] In the following explanation, "%" and "parts" used to express quantities refer to weight unless otherwise specified. Furthermore, the operations described below were performed under normal temperature (20°C ± 15°C) and atmospheric pressure (1 atm) conditions unless otherwise specified.

[0157] <Evaluation Method> (Thickness of each layer in a multilayer optical film) The film was sliced ​​into 0.05 μm thicknesses using a microtome (RV-420, manufactured by Yamato Koki Co., Ltd.), and the thickness of each layer was measured by observing the cross-section under a microscope.

[0158] (Average primary particle size of fine particles) A water slurry with a particle concentration of 2% by weight was prepared and measured using the "nanoSAQLA Multi-Sample Nanoparticle Size Measurement System" (manufactured by Otsuka Electronics), a particle size distribution analyzer that uses dynamic light scattering. The average primary particle size represents the particle size at 50% of the cumulative value in the particle size distribution determined by dynamic light scattering.

[0159] (Measurement of interparticle distance) A section of the multilayer optical film was cut from the center in the width direction, and the cross-section including the thickness direction of the multilayer optical film was observed using a scanning electron microscope (JEOL Ltd. "JSM-7401F"). The magnification was 10,000x, and the size of the observation field was 12 μm × 9 μm. The distance between a given particle and the particle closest to it was measured and recorded as the shortest distance. For 10 particles in the observation field, the shortest distance was measured, and the longest distance among these 10 shortest distances was recorded as the distance between particles.

[0160] (Measurement of the longest diameter of the fine particles) The central portion of the multilayer optical film in the width direction was cut out, and the cross-section including the thickness direction of the multilayer optical film was observed using a scanning electron microscope (JEOL Ltd. "JSM-7401F"). The magnification was 10,000x, and the size of the observation field was 12 μm × 9 μm. The major axis of 10 arbitrary particles within the observation field was measured, and the average of these measurements was taken as the major axis of the fine particles.

[0161] (R1: UV absorber content in the center of the inner layer in the thickness direction) Using a microtome (RV-240, manufactured by Yamato Koki Kogyo Co., Ltd.), a portion of the B layer, which is the fine particle layer, and a portion of the A layer, which is the inner layer, near the B layer were removed from the surface, leaving the portion of the A layer near the center in the thickness direction (the central part in the thickness direction). The thickness of the central part in the thickness direction was 20 μm. A cyclohexane solution of the UV absorber LA-31 (Adekastab LA-31) was prepared, and the absorbance at 350 nm was measured using a visible-UV spectrophotometer (JASCO Corporation "V-750") to create a calibration curve between the UV absorber concentration and the absorbance at 350 nm. A cyclohexane solution was prepared from the center of layer A in the thickness direction, and the absorbance at 350 nm was measured. The concentration of the ultraviolet absorber (content R1) in the center of layer A in the thickness direction was obtained from the calibration curve.

[0162] (Thickness of the outer layer and the content of the ultraviolet absorber at a depth of 750 nm from the surface of the multilayer optical film R2) The intensity of fragment ions originating from the UV absorber LA-31 was measured in the depth direction from the surface of a multilayer optical film using the GCIB-TOF-SIMS method. The measurement conditions were as follows. • Primary ion: Bi3++ • Secondary ion polarity: Negative • Etching ions: Ar gas cluster ion beam (Ar-GCIB) The relative intensity of fragment ions derived from the UV absorber LA-31 in layer B was calculated by setting the intensity of fragment ions derived from the UV absorber LA-31 in the center of layer A in the thickness direction to 1. From the ultraviolet absorber concentration (content R1) in the center of the thickness direction of layer A, obtained from an ultraviolet spectrophotometer, and the relative intensity of fragment ions derived from the ultraviolet absorber LA-31 in layer B, the concentration distribution of the ultraviolet absorber LA-31 in the thickness direction of layer B was determined. From the concentration distribution, the thickness of the layer (outer layer) in which the concentration of ultraviolet absorber LA-31 is 0.01% by weight or less, and the ultraviolet absorber concentration (content R2) at a depth of 750 nm from the surface of the multilayer optical film were obtained.

[0163] (Static friction coefficient of multilayer optical film) Using a friction testing machine (TR-2, manufactured by Toyo Seiki Seisakusho), the static friction coefficient of the films obtained in each example was measured in accordance with JIS K7125. The measurement was performed under the conditions of a test specimen size of 140 mm x 65 mm, a load of 1 kgf, and a speed of 500 mm / min. A smaller static friction coefficient indicates greater slipperiness of the film.

[0164] (Appearance of a multilayer optical film roll) The appearance of 2000m rolls of multilayer optical film was evaluated by visual inspection and tactile examination. Film rolls without polygonal indentations on their surface were classified as "good," while those with polygonal indentations on their surface were classified as "poor."

[0165] (Roll stains) The contamination of the cooling roll, which is the first point of contact for the molten resin composition emerging from the T-die, was visually observed. Observations were conducted after continuous film formation for 24 hours and 168 hours. Roll contamination was evaluated using the following indicators. A: No contamination of the cooling rolls was observed visually. B: Contamination of the cooling roll was observed visually.

[0166] (Method for evaluating the adhesion strength of the hard coat layer (peel test)) Nine samples were cut from a hard-coated optical film. For each sample, a cellophane tape grid peel test was performed in accordance with JIS K5600-5-6. Specifically, notches were made in the hard-coated layer to form 100 2mm x 2mm sections in a grid pattern. Cellophane tape (manufactured by Nichiban, 24mm wide) was applied to the 100 sections and peeled off within 1 second. The number of sections that remained on the optical film without peeling off after the cellophane tape was counted. On average, samples with 95 or more sections remaining were judged as "Excellent," samples with 90 or more but less than 95 sections were judged as "Good," samples with 80 or more but less than 90 sections were judged as "Acceptable," and samples with fewer than 80 sections remaining were judged as "Poor."

[0167] <Materials used in the example> (Resins containing polymers with alicyclic structures) Zeon Corporation's "Zeonor 1600" was used. Hereinafter, resins containing polymers with alicyclic structures will also be referred to as polymer resins containing alicyclic structures, or simply polymer resins.

[0168] (UV absorber) We used ADEKA's "ADEKA Stab LA-31".

[0169] (fine particles) As the fine particles, one of the following particles A to D was used. Particle A: Spherical oxide microparticles "AdmaFine SC101G" manufactured by Admatex, average primary particle size 0.30 μm Particle B: Nippon Shokubai's polymethyl methacrylate-based nanocrosslinked particles "Epostor MX," average primary particle diameter 0.35 μm Particle C: Spherical oxide microparticles "QSG30" manufactured by Shin-Etsu Chemical Co., Ltd., average primary particle size 0.03 μm Particle D: Spherical oxide microparticles "AdmaFine SO-C5" manufactured by Admatex, average primary particle size 1.5 μm

[0170] (Liquid composition for hard coat layer) A liquid composition for hard coat layers prepared according to the following procedure was used. A UV-curable polymerizable monomer composition (R1) was prepared containing dipentaerythritol hexaacrylate (hereinafter sometimes abbreviated as "DP6A"), dipentaerythritol pentaacrylate (hereinafter sometimes abbreviated as "DP5A"), and dipentaerythritol tetraacrylate (hereinafter sometimes abbreviated as "DP4A"). In this polymerizable monomer composition (R1), the weight ratio of each component was DP6A / DP5A / DP4A = 64 / 17 / 19. The solid content concentration of the polymerizable monomer composition (R1) was 100%.

[0171] A polyfunctional urethane acrylate (U1) was prepared by reacting 222 parts by weight of isophorone diisocyanate with 795 parts by weight of a mixture of pentaerythritol triacrylate (hereinafter sometimes abbreviated as "PE3A") and pentaerythritol tetraacrylate (hereinafter sometimes abbreviated as "PE4A") (PE3A / PE4A = 75 / 25 (weight ratio)). The solid content concentration of this polyfunctional urethane acrylate (U1) was 100%.

[0172] A mixed ethanol was prepared, which was a mixture of ethanol, n-propyl alcohol, methanol, and water. In this mixed ethanol, the weight ratio of each component was ethanol / n-propyl alcohol / methanol / water = 85.5 / 9.6 / 4.9 / 0.2.

[0173] A mixture was obtained by thoroughly mixing 29.4 parts by weight of the polymerizable monomer composition (R1) and 12.6 parts by weight of the polyfunctional urethane acrylate (U1) (42.9 parts by weight per 100 parts by weight of composition (R1)) with 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.'s "Irgacure 184", 100% solids) (2.9 parts by weight per 100 parts by weight of composition (R1)). To this mixture, 35.0 parts by weight of a dispersion of metal oxide particles (P1) (20% solid content, number-average particle size 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% solid content) were added and uniformly mixed to obtain liquid composition (H1) for the hard coat layer. (Solid content of liquid composition (H1): 50.1 parts by weight (solid content concentration: 54.0% by weight))

[0174] <Manufacturing apparatus for thermoplastic resin composition (B)> A twin-screw extruder with the following configuration was used as the manufacturing apparatus for thermoplastic resin composition (B).

[0175] (Twin-screw extruder 1) The twin-screw extruder 1 had a cylinder equipped with two feed ports (resin feed port and fine particle feed port) to which two weight feeders were connected, one vent port, and one discharge port connected to a die, and a screw with a kneading disc positioned on a full-flight screw, and had a conveying zone where resin or resin composition was conveyed by the full-flight screw, and three kneading zones (first kneading zone, second kneading zone, and third kneading zone) where resin or resin composition was kneaded by the kneading disc. Inside the cylinder, the conveying zones and kneading zones were arranged alternately along the direction of resin flow, with the first conveying zone, first kneading zone, second conveying zone, second kneading zone, third conveying zone, third kneading zone, and fourth conveying zone being arranged in this order. The resin feed port was located in the first conveying zone. The fine particle feed port was located in the second conveying zone, which was positioned between the first kneading zone and the second kneading zone.

[0176] (Twin-screw extruder 2) Twin-screw extruder 2 had the same configuration as twin-screw extruder 1, except for the configuration described below. The twin-screw extruder 2 had two kneading zones (a first kneading zone and a second kneading zone), and inside the cylinder, the first conveying zone, first kneading zone, second conveying zone, second kneading zone, and third conveying zone were arranged in this order along the direction of resin flow. The resin supply port was located in the first conveying zone, and the fine particle supply port was located in the second conveying zone, situated between the first and second kneading zones.

[0177] (Twin-screw extruder 3) Twin-screw extruder 3 had the same configuration as twin-screw extruder 1, except for the configuration described below. The twin-screw extruder 3 had a resin supply port located in the first conveying zone, and a fine particle supply port located in the third conveying zone, situated between the second and third kneading zones.

[0178] (Twin-screw extruder 4) Twin-screw extruder 4 had the same configuration as twin-screw extruder 1, except for the configuration described below. The twin-screw extruder 4 had one kneading zone. Inside the cylinder of the twin-screw extruder 4, a first conveying zone, a first kneading zone, and a second conveying zone were arranged in this order along the direction of resin flow. Both the resin supply port and the fine particle supply port were located in the first conveying zone.

[0179] <Example 1> (1-1. Manufacturing of thermoplastic resin composition (A)) A thermoplastic resin composition (A) was obtained by mixing 95 parts by weight of "Zeonor 1600" manufactured by Nippon Zeon Co., Ltd. as a polymer resin containing an alicyclic structure and 5 parts by weight of "ADEKA Stab LA-31" manufactured by ADEKA Corporation as an ultraviolet absorber using a twin-screw extruder.

[0180] (1-2. Manufacturing of thermoplastic resin composition (B)) As a polymer resin containing an alicyclic structure, we prepared "Zeonor 1600" manufactured by Nippon Zeon Corporation, and particle A (spherical oxide microparticles "AdmaFine SC101G" manufactured by Admatex, with an average primary particle size of 300 nm). A polymer resin containing an alicyclic structure was fed into a weight feeder connected to the resin supply port of the twin-screw extruder 1, which has three kneading zones, and particles A were fed into a weight feeder connected to the fine particle supply port. From each weight feeder, a polymer resin containing an alicyclic structure and particles A were fed into the cylinder of the twin-screw extruder 1 in a ratio such that the content of particles A in the resulting resin composition was 5% by weight. The polymer resin containing an alicyclic structure was introduced into the first transport zone within the cylinder from the resin supply port. Particle A was introduced into the second transport zone within the cylinder from the fine particle supply port. The polymer resin containing the alicyclic structure was sent to the first kneading zone via a full-flight screw in the first transport zone, kneaded in the first kneading zone where a kneading disc was located, and then sent to the second transport zone. The polymer resin containing the alicyclic structure, together with particles A introduced into the second transport zone, was sent from the second transport zone to the second kneading zone, where it was plasticized by a kneading disc located in the second kneading zone and kneaded with particles A. The polymer resin containing the alicyclic structure and particles A kneaded in the second kneading zone were further sent sequentially to the third transport zone and the third kneading zone, where they were kneaded to obtain a mixture in which particles A were dispersed within the polymer resin containing the alicyclic structure. Next, the kneaded material was sent from the third kneading zone to the die through a vent located in the section from the third kneading zone to the die (vent zone), while being degassed with a vacuum pump. The kneaded material sent to the die was extruded from the die in a strand shape, cooled in a water tank, and cut into pellets with a pelletizer to obtain thermoplastic resin composition (B).

[0181] (1-3. Forming of multilayer optical films) (Film manufacturing equipment) A film manufacturing apparatus was prepared comprising a co-extrusion film molding machine equipped with a single-layer die having a lip portion formed thereon that can discharge a molten composition, a cast roll having a circumferential surface capable of receiving a molten film formed from the molten composition extruded from the lip portion of the die, a cooling roll provided downstream of the cast roll, and a winding machine provided downstream of the cooling roll. The single-layer die in the co-extrusion film molding machine was equipped with a heater that could adjust the die to a desired temperature. The co-extrusion film molding machine also included a feed block connected to the single-layer die, which was designed to co-extrude two types of resin supplied to the feed block into three layers through the lip of the single-layer die. The lip length (corresponding to the width of the molten film) was 750 mm. The cast roll was positioned so that its circumferential surface faced the lip portion of the single-layer die. Furthermore, the cast roll was designed to rotate circumferentially at a desired set speed. In addition, an electrostatic pinning device was provided near the circumferential surface of the cast roll, capable of bringing the edge of the molten film into close contact with the circumferential surface at a point immediately downstream of the position where the molten film is received.

[0182] (Film manufacturing) The thermoplastic resin composition (A) and thermoplastic resin composition (B) described above were supplied to the feed block of a co-extrusion film molding machine so as to obtain a molten film having, in this order, a first fine particle layer (layer B formed from thermoplastic resin composition (B)), an inner layer (layer A formed from thermoplastic resin composition (A)), and a second fine particle layer (layer B formed from thermoplastic resin composition (B)). The supplied thermoplastic resin composition (A) and thermoplastic resin composition (B) were melted and sent to a single-layer die set to 280°C. The molten thermoplastic resin composition (A) and thermoplastic resin composition (B) then merged in the single-layer die to form layers, and this molten composition containing the layered thermoplastic resin composition (A) and thermoplastic resin composition (B) was extruded through the lip portion into a film. The molten composition extruded from the lip portion yielded a molten film having, in this order, a layer of thermoplastic resin composition (B) as the first fine particle layer, a layer of thermoplastic resin composition (A) as the inner layer, and a layer of thermoplastic resin composition (B) as the second fine particle layer.

[0183] The molten film extruded from the lip section was received on the surface of a cast roll with a surface temperature of 155°C and a surface speed of 5 m / min. Immediately thereafter, an electrostatic pinning device brought the surfaces of the first fine particle layer on both ends of the molten film in the width direction into contact with the surface of the cast roll. Subsequently, the molten film was cooled while being transported downstream as the cast roll rotated, resulting in a multilayer optical film having a B layer corresponding to the first fine particle layer, an A layer corresponding to the inner layer, and a B layer corresponding to the second fine particle layer in that order. The width of the obtained film was 500 mm and the winding length was 1000 m. The thicknesses of the constituent layers of the film (first fine particle layer / inner layer / second fine particle layer) were 1.5 μm / 37 μm / 1.5 μm. The obtained multilayer optical films were evaluated using the method described above.

[0184] (1-4. Manufacturing of hard-coated optical films) (1-4-1. Formation of UV-curable resin layer (pre-curing layer)) One side of the resulting multilayer optical film was subjected to corona treatment (output 0.4kW, discharge rate 200W·min / m²). 2 A corona-treated multilayer optical film was subjected to a hard coat layer. A liquid composition (H1) for the hard coat layer was applied to the surface of the corona-treated multilayer optical film using a bar coater in an environment of 50% relative humidity, such that the thickness of the hard coat layer obtained after curing was approximately 4 to 6 μm. Subsequently, the applied film of liquid composition (H1) was dried at 120°C for 1 minute to form an ultraviolet-curable resin layer (pre-curing layer) on the main surface of the multilayer optical film, thereby obtaining a laminated film comprising a multilayer optical film and an ultraviolet-curable resin layer.

[0185] (1-4-2. Ultraviolet irradiation process) A laminated film comprising the aforementioned multilayer optical film and an ultraviolet-curable resin layer is subjected to a high-pressure mercury lamp with a peak illuminance of 330 mW / cm². 2 , integrated light intensity 200 mJ / cm 2 The UV-curable resin layer was cured by irradiating it with light in the measurement wavelength range of 320 nm to 390 nm, forming a hard coat layer. This resulted in a hard-coated optical film comprising a multilayer optical film and a hard coat layer. The obtained hard-coated optical films were evaluated using the method described above.

[0186] <Example 2> (2-1. Manufacturing of thermoplastic resin composition (A)) In (1-1), the amount of Zeon Corporation's "Zeonor 1600" was changed to 93 parts by weight, and the amount of ultraviolet absorber (ADEKA Corporation's "ADEKA Stab LA-31") was changed to 7 parts by weight. Except for the above, the procedure was carried out in the same manner as in (1-1) to obtain thermoplastic resin composition (A).

[0187] (2-2. Manufacturing of thermoplastic resin composition (B)) In (1-2), a twin-screw extruder 2 equipped with two kneading zones was used instead of twin-screw extruder 1. From two weight feeders, a polymer resin containing an alicyclic structure and particles A were fed into the cylinder of a twin-screw extruder 2 in a ratio such that the content of particles A in the resulting resin composition was 7% by weight. From a vent located between the second mixing zone and the die, the mixture of polymer resin containing an alicyclic structure, which was mixed in the second mixing zone, and particle A was sent to the die while being degassed with a vacuum pump. Except for the matters mentioned above, the procedure was carried out in the same manner as in (1-2) to obtain thermoplastic resin composition (B).

[0188] (2-3. Forming of multilayer optical films) In (1-3), the thickness of each of the constituent layers of the film (first microparticle layer / inner layer / second microparticle layer) was changed to 2 μm / 56 μm / 2 μm by changing the supply rate of thermoplastic resin composition (A) and thermoplastic resin composition (B) to the feed block. Except for the matters mentioned above, the procedure was carried out in the same manner as in (1-3) to obtain a multilayer optical film. The obtained multilayer optical film was evaluated using the method described above.

[0189] (2-4. Manufacturing of hard-coated optical films) Using the obtained multilayer optical film, the same operations as in (1-4) were performed to obtain a hard coat optical film. The obtained hard coat optical film was evaluated by the above method.

[0190] <Example 3> (3-1. Production of Thermoplastic Resin Composition (A)) Performing the same operations as in (1-1), a thermoplastic resin composition (A) was obtained.

[0191] (3-2. Production of Thermoplastic Resin Composition (B)) In (1-2), instead of the twin-screw extruder 1, a twin-screw extruder 3 having three kneading zones was used. A polymer resin containing an alicyclic structure was charged into the gravimetric feeder connected to the resin supply port of the twin-screw extruder 3, and particles B (polymethyl methacrylate-based nano-crosslinked particles "Epistar MX" manufactured by Nippon Shokubai Co., Ltd.) were charged into the gravimetric feeder connected to the fine particle supply port. From each gravimetric feeder, the polymer resin containing an alicyclic structure and particles B were charged into the cylinder of the twin-screw extruder 3 at a ratio such that the content of particles B in the resulting resin composition was 5% by weight. The polymer resin containing an alicyclic structure was charged into the first conveyance zone in the cylinder from the resin supply port. Particles B were charged into the third conveyance zone in the cylinder from the fine particle supply port. While degassing with a vacuum pump from the vent port provided in the section from the third kneading zone to the die (vent zone), the kneaded product was sent from the third kneading zone to the die. Except for the above matters, the same operations as in (1-2) were performed to produce a thermoplastic resin composition (B).

[0192] (3-3. Molding of Multilayer Optical Film) In (1-3), by changing the supply rates of the thermoplastic resin composition (A) and the thermoplastic resin composition (B) to the feed block, the thicknesses of each layer of the film (first fine particle layer / inner layer / second fine particle layer) were changed to 3 μm / 64 μm / 3 μm. For matters other than those described above, the same operations as in (1-3) were performed to obtain a multilayer optical film. The obtained multilayer optical film was evaluated by the above method.

[0193] (3-4. Production of Hard Coat Optical Film) Using the obtained multilayer optical film, the same operations as in (1-4) were performed to obtain a hard coat optical film. The obtained hard coat optical film was evaluated by the above method.

[0194] <Example 4> (4-1. Production of Thermoplastic Resin Composition (A)) The same operations as in (1-1) were performed to obtain a thermoplastic resin composition (A).

[0195] (4-2. Production of Thermoplastic Resin Composition (B)) In (1-2), a polymer resin containing an alicyclic structure was introduced into the gravimetric feeder connected to the resin supply port of the twin-screw extruder 1, and Particle A was introduced into the gravimetric feeder connected to the fine particle supply port. From each gravimetric feeder, the polymer resin containing an alicyclic structure and Particle A were introduced into the cylinder of the twin-screw extruder 1 at a ratio such that the content of Particle A in the resulting resin composition was 3% by weight. For matters other than those described above, the same operations as in (1-2) were performed to obtain a thermoplastic resin composition (B).

[0196] (4-3. Molding of Multilayer Optical Film) The same operations as in (1-3) were performed to obtain a multilayer optical film. The obtained multilayer optical film was evaluated by the above method.

[0197] (4-4. Production of Hard Coat Optical Film) Using the obtained multilayer optical film, the same operations as in (1-4) were performed to obtain a hard coat optical film. The obtained hard coat optical film was evaluated by the above method.

[0198] <Example 5> A thermoplastic resin composition (A) was obtained by following the same procedure as in (1-1). The procedure described in (1-2. Manufacturing of thermoplastic resin composition (B)) was not performed.

[0199] In (1-3), a polymer resin containing an alicyclic structure (Zeonor 1600, manufactured by Zeon Corporation) was used instead of the thermoplastic resin composition (B). Furthermore, by changing the supply rate of the thermoplastic resin composition (A) and the polymer resin containing an alicyclic structure to the feed block, the thickness of each constituent layer of the film (polymer resin layer / inner layer / polymer resin layer) was changed to 0.5 μm / 29 μm / 0.5 μm. A multilayer optical film was obtained by performing the same procedure as in Example 1, except for the matters mentioned above. The obtained multilayer optical film was evaluated using the method described above.

[0200] (5-4. Manufacturing of hard-coated optical films) Using the obtained multilayer optical film, a hard-coated optical film was obtained by the same procedure as in (1-4). The obtained hard-coated optical film was evaluated using the method described above.

[0201] <Comparative Example 1> (C1-1. Manufacture of thermoplastic resin composition (A)) A thermoplastic resin composition (A) was obtained by following the same procedure as in (1-1).

[0202] (C1-2. Manufacture of thermoplastic resin composition (B)) In (1-2), a twin-screw extruder 4 equipped with a single kneading zone was used instead of twin-screw extruder 1. Both the polymer resin containing the alicyclic structure and particles A were fed into the first conveying zone in the cylinder. The mixed material was sent from the first mixing zone to the die through a vent located in the section between the first mixing zone and the die, while being degassed by a vacuum pump. Except for the matters mentioned above, the procedure was carried out in the same manner as in (1-2) to obtain thermoplastic resin composition (B).

[0203] (C1-3. Forming of multilayer optical films) In (1-3), by changing the supply rates of the thermoplastic resin composition (A) and the thermoplastic resin composition (B) to the feed block, the respective thicknesses of the constituent layers of the film (first fine particle layer / inner layer / second fine particle layer) were changed to 2 μm / 26 μm / 2 μm. Except for the above matters, the operation was carried out in the same manner as in (1-3) to obtain a multilayer optical film. The obtained multilayer optical film was evaluated by the above method.

[0204] (C1-4. Production of hard coat optical film) Using the obtained multilayer optical film, the operation was carried out in the same manner as in (1-4) to obtain a hard coat optical film. The obtained hard coat optical film was evaluated by the above method.

[0205] <Comparative Example 2> (C2-1. Production of thermoplastic resin composition (A)) The thermoplastic resin composition (A) was obtained by operating in the same manner as in (1-1).

[0206] (C2-2. Production of thermoplastic resin composition (B)) A polymer resin containing an alicyclic structure was charged into the gravimetric feeder connected to the resin supply port of the twin-screw extruder 1, and particle C (spherical oxide fine particles "QSG30" manufactured by Shin-Etsu Chemical Co., Ltd.) was charged into the gravimetric feeder connected to the fine particle supply port. Except for the above matters, the operation was carried out in the same manner as in (1-2) to obtain the thermoplastic resin composition (B).

[0207] (C2-3. Molding of multilayer optical film) The operation was carried out in the same manner as in (1-3) to obtain a multilayer optical film. The obtained multilayer optical film was evaluated by the above method.

[0208] (C2-4. Production of hard coat optical film) Using the obtained multilayer optical film, the operation was carried out in the same manner as in (1-4) to obtain a hard coat optical film. The obtained hard coat optical film was evaluated by the above method.

[0209] <Comparative Example 3> (C3-1. Manufacture of thermoplastic resin composition (A)) A thermoplastic resin composition (A) was obtained by following the same procedure as in (1-1).

[0210] (C3-2. Manufacture of thermoplastic resin composition (B)) A polymer resin containing an alicyclic structure was fed into a weight feeder connected to the resin supply port of twin-screw extruder 1, and particles D (Admatex's spherical oxide microparticles "AdmaFine SO-C5") were fed into a weight feeder connected to the microparticle supply port. Except for the matters mentioned above, the procedure was carried out in the same manner as in (1-2) to obtain thermoplastic resin composition (B).

[0211] (C3-3. Forming of multilayer optical films) In (1-3), the thickness of each of the constituent layers of the film (first microparticle layer / inner layer / second microparticle layer) was changed to 3 μm / 37 μm / 3 μm by changing the supply rate of thermoplastic resin composition (A) and thermoplastic resin composition (B) to the feed block. Except for the matters mentioned above, a multilayer optical film was obtained by the same procedure as in (1-3). The obtained multilayer optical film was evaluated using the method described above.

[0212] (C3-4. Manufacturing of hard-coated optical films) Using the obtained multilayer optical film, a hard-coated optical film was obtained by the same procedure as in (1-4). The obtained hard-coated optical film was evaluated using the method described above.

[0213] <Comparative Example 4> (C4-1. Manufacture of thermoplastic resin composition (A)) A thermoplastic resin composition (A) was obtained by following the same procedure as in (1-1).

[0214] (C4-2. Manufacture of thermoplastic resin composition (B)) From each weight feeder, a polymer resin containing an alicyclic structure and particles A were fed into the cylinder of the twin-screw extruder 1 in a ratio such that the content of particles A in the resulting resin composition was 1% by weight. Except for the matters mentioned above, the procedure was carried out in the same manner as in (1-2) to obtain thermoplastic resin composition (B).

[0215] (C4-3. Forming of multilayer optical films) A multilayer optical film was obtained by following the same procedure as in (1-3). The obtained multilayer optical film was evaluated using the method described above.

[0216] (C4-4. Manufacturing of hard-coated optical films) Using the obtained multilayer optical film, a hard-coated optical film was obtained by the same procedure as in (1-4). The obtained hard-coated optical film was evaluated using the method described above.

[0217] <Comparative Example 5> (C5-1. Manufacture of thermoplastic resin composition (A)) In (1-1), the amount of Zeon Corporation's "Zeonor 1600" was changed to 75 parts by weight, and the amount of ultraviolet absorber (ADEKA Corporation's "ADEKA Stab LA-31") was changed to 25 parts by weight. Except for the above, the procedure was carried out in the same manner as in (1-1) to obtain thermoplastic resin composition (A).

[0218] (C5-2. Manufacture of thermoplastic resin composition (B)) Thermoplastic resin composition (B) was obtained by following the same procedure as in (1-2).

[0219] (C5-3. Forming of multilayer optical films) A multilayer optical film was obtained by following the same procedure as in (1-3). The obtained multilayer optical film was evaluated using the method described above.

[0220] (C5-4. Manufacturing of hard-coated optical films) Using the obtained multilayer optical film, a hard-coated optical film was obtained by the same procedure as in (1-4). The obtained hard-coated optical film was evaluated using the method described above.

[0221] <Result> The results are shown in the table below. In the multilayer optical films obtained in each example, the content of the ultraviolet absorber on the surface was 0.00% by weight, and the content of the ultraviolet absorber in the intermediate layer had a distribution that gradually decreased as it moved away from the inner layer. The terms in the following table have the following meanings. Total thickness: Thickness of the multilayer optical film R1: Content of UV absorber in the center of the thickness direction of the inner layer. Number of mixing zones: The number of mixing zones in a twin-screw extruder for producing thermoplastic resin composition (B). Particle supply location: The supply location of the fine particles. The description in the particle supply location section has the following meanings: "Between 1 and 2" indicates that the particles were supplied to the second transport zone, which is located between the first and second mixing zones. "Between 2 and 3" indicates that the particles were supplied to the third transport zone, which is located between the second and third mixing zones. "In front of 1" indicates that the particles were supplied to the first transport zone, which is located in front of the first mixing zone. t b : The thickness of one of the two microparticle layers in a multilayer optical film. The thicknesses of the two microparticle layers in a multilayer optical film are equal, t b =t b1 =t b2 That is the case. Interparticle distance: The distance between fine particles (P). Average particle size: The average primary particle size of fine particles (P). R2: Content of ultraviolet absorber at a depth of 750 nm from the surface of the multilayer optical film. Appearance of the roll: The appearance of a multilayer optical film roll. HC: Hard coat layer

[0222] [Table 1]

[0223] *1 in Table 1: Shows the total thickness of the outer layer (one side) and the intermediate layer (one side).

[0224] [Table 2]

[0225] From the above results, it can be seen that the multilayer optical films according to Examples 1 to 5 have superior adhesion to the hard coat layer compared to Comparative Examples 1 to 5, and that they can suppress roll contamination. The multilayer optical film according to Comparative Example 1 does not have an outer layer formed, L p / t b It is 0.45, which is greater than 0.30. The multilayer optical film in Comparative Example 2 has an outer layer thickness of 600 nm, exceeding 500 nm, and an average particle size of fine particles of 0.03 μm, less than 0.10 μm. Furthermore, the percentage (R2 / R1 × 100) is 2%, less than 5%. The multilayer optical film according to Comparative Example 3 does not have an outer layer formed, L p / t b The ratio is 0.50 and exceeds 0.30. Also, the average particle size of the fine particles is 1.50 μm and exceeds 0.80 μm. The multilayer optical film according to Comparative Example 4 has an outer layer thickness of 1000 nm and exceeds 500 nm, an interparticle distance of 1200 nm and exceeds 1000 nm, and a fine particle content of 1% by weight and less than 2% by weight. The multilayer optical film according to Comparative Example 5 has no outer layer, and the content R1 of the ultraviolet absorber in the center of the thickness direction of the inner layer is 25% by weight, which is greater than 20% by weight. As described above, the multilayer optical films according to Comparative Examples 1 to 5, in which the predetermined outer layer is not formed, have poor adhesion to the hard coat layer. [Explanation of Symbols]

[0226] 100 Multilayer Optical Film 100U,100D surface 110a,110b outer layer 120a,120b middle layer 130 Inner layer 130U,130D surface 130C, center surface in the thickness direction 131 Center in the thickness direction 131U,131D plane 200 multilayer optical film 200U,200D surface 210a,210b outer layer 220a,220b middle layer 240a,240b Fine particle layer 300 multilayer optical film 310 Hard Coat Layer 1000 extruders 1100 Cylinder 1110 Wall section 1120 Mixing Room 1130 Resin supply port 1140 Particulate supply port 1150 Vent opening 1160 Discharge port 1200 screw 1210 Conveyor element 1220 Mixing Element 1230 axis 1301, 1302, 1303 Mixing Zone 1401, 1402, 1403, 1403 Transport Zone

Claims

1. A multilayer optical film comprising a first outer layer, an inner layer, and a second outer layer in this order, The inner layer comprises an ultraviolet absorber and a polymer containing an alicyclic structure. The first outer layer and the second outer layer are each positioned on the outermost surface of the multilayer optical film, have a thickness of 200 nm to 500 nm, contain a polymer including an alicyclic structure, and have a UV absorber content of 0.01% by weight or less. The content R of the ultraviolet absorber in the center of the thickness direction of the inner layer １ The amount is 1% by weight or more and 20% by weight or less. The content R of the ultraviolet absorber at a depth of 750 nm in the multilayer optical film. ２ The aforementioned content R １ Percentage of (R ２ / R １ A multilayer optical film in which the ratio (x100) is 5% or more.

2. A multilayer optical film according to claim 1, comprising a first microparticle layer, the inner layer, and a second microparticle layer in this order, The first fine particle layer includes the first outer layer, The second fine particle layer includes the second outer layer, The first fine particle layer and the second fine particle layer each contain a polymer having an alicyclic structure and fine particles (P) at a content of 2% by weight or more and 7% by weight or less, the distance between the fine particles (P) is 300 nm or more and 1000 nm or less, and the major axis L of the fine particles (P) ｐ of the thickness t of the first fine particle layer ｂ１ The ratio (L ｐ / t ｂ１ ) and the major axis L of the fine particles (P) ｐ of the thickness t of the second fine particle layer ｂ２ The ratio (L ｐ / t ｂ２ ) is 0.30 or less. The multilayer optical film according to claim 1.

3. The multilayer optical film according to claim 2, wherein the fine particles (P) have an average primary particle diameter of 0.10 μm or more and 0.80 μm or less.

4. The aforementioned thickness t ｂ１ and the thickness t ｂ２ The multilayer optical film according to claim 2, wherein either or both of the elements are 1.0 μm or more and 5.0 μm or less.

5. A hard-coated optical film comprising a multilayer optical film as described in claim 1 and a hard-coat layer provided on the multilayer optical film.

6. A hard-coated optical film comprising a multilayer optical film according to any one of claims 2 to 4 and a hard-coated optical film provided on the multilayer optical film.

7. A method for manufacturing a multilayer optical film according to any one of claims 2 to 4, Step (1) to produce a thermoplastic resin composition (B) by kneading a resin containing a polymer with an alicyclic structure and the fine particles (P) in an extruder having at least two kneading zones, with 2% by weight or more and 7% by weight or less; and The step (2) includes forming the first fine particle layer and the second fine particle layer from the thermoplastic resin composition (B); The above step (1) includes a step (1a) of kneading a resin containing the polymer containing the alicyclic structure in a first kneading zone located at the uppermost part of the extruder among the at least two kneading zones, and a step (1b) of supplying the fine particles (P) downstream of the first kneading zone and kneading the resin containing the polymer containing the alicyclic structure and the fine particles (P). A method for manufacturing multilayer optical films.

8. A method for manufacturing a hard-coated optical film according to claim 6, A step of forming an ultraviolet-curable resin layer on the multilayer optical film; and, The process includes irradiating the resin layer with ultraviolet light to form the hard coat layer; A method for manufacturing hard-coated optical films.

Images