Polarizing film, image display device, and method for manufacturing polarizing film

Abstract

The present invention provides a polarizing film capable of sufficiently suppressing the permeation of iodine contained in a polarizer to the outside in a high-temperature and high-humidity environment. The polarizing film of the present invention includes: a polarizer containing iodine, and a resin layer containing a polymer having a structural unit derived from (meth)acrylate. In the polarizing film, the value of y1 calculated by the following formula (1) is less than 1.3, y1 = (0.279)x1 + (-1.51)x2 + (0.178)x3 + 0.386 (1). In formula (1), x1 is the number of rotatable bonds contained in the monomer for forming the polymer, x2 is the number of reaction points contained in the monomer, and x3 is the polar term δP (MPa 1 / 2 ) of the Hansen solubility parameter of the monomer.

Description

Technical Field

[0001] The present invention relates to a polarizing film, an image display device and a method for manufacturing the polarizing film. Background Art

[0002] Image display devices such as liquid crystal display devices and organic EL display devices are equipped with polarizing films for reasons such as their display principles. Polarizing films are, for example, laminates comprising polarizers and transparent protective films. Polarizers can generally be made by adsorbing dichroic pigments on hydrophilic polymer films such as polyvinyl alcohol (PVA) films and uniaxially stretching the films. From the viewpoint of improving the transmittance and polarization degree of polarizers, iodine is widely used as a dichroic pigment.

[0003] Patent Document 1 discloses an optical laminated body in which a polarizer and a protective film are bonded via a cured layer of a curable resin composition. According to Patent Document 1, by appropriately adjusting the content of the alicyclic epoxy compound in the curable resin composition, the iodine content in the cured layer can be kept at a low level even when the optical laminated body is placed in a high-temperature and high-humidity environment.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-169512 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In a high temperature and high humidity environment, there is a tendency for the iodine contained in the polarizer to move from the polarizer to the transparent protective film, or to the adhesive layer used to attach the polarizing film to the image display panel. In particular, when the thickness of the polarizer is small and the concentration of iodine in the polarizer is high, iodine tends to move from the polarizer to the transparent protective film or the adhesive layer. The iodine that moves to the transparent protective film or the adhesive layer passes through the transparent protective film or the adhesive layer to the outside of the polarizing film. If the iodine content in the polarizer decreases, the polarization degree of the polarizing film decreases.

[0009] With respect to existing polarizing films, it is not possible to sufficiently suppress the transmission of iodine contained in the polarizer to the outside of the polarizing film in a high-temperature, high-humidity environment. For example, Patent Document 1 focuses on maintaining the iodine content in the cured layer at a low level when the optical laminate is placed in a high-temperature, high-humidity environment. However, Patent Document 1 does not consider the transmission of iodine from the polarizer to the outside of the optical laminate.

[0010] Therefore, an object of the present invention is to provide a polarizing film capable of sufficiently suppressing the transmission of iodine contained in a polarizer to the outside in a high-temperature and high-humidity environment.

[0011] Solutions to the problem

[0012] The present inventors have conducted in-depth research and have newly discovered that the properties of the resin layer of the polarizing film can be predicted based on the monomers used to form the polymer contained in the resin layer. According to the research of the present inventors, the prediction is particularly reliable for the resin layer containing a polymer having a structural unit derived from a (meth)acrylate. Based on this understanding, the present inventors have further conducted research and completed the present invention.

[0013] The present invention provides a polarizing film, which comprises:

[0014] A polarizer containing iodine, and

[0015] a resin layer comprising a polymer having a structural unit derived from a (meth)acrylate,

[0016] Here, y calculated by the following formula (1) 1 The value of is less than 1.3,

[0017] y 1 =(0.279)x 1 +(-1.51)x 2 +(0.178)x 3 +0.386 (1)

[0018] In the above formula (1), x 1 is the number of rotatable bonds contained in the monomer used to form the above polymer,

[0019] x 2 is the number of reaction sites contained in the above monomer used to form the above polymer,

[0020] x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the above monomer used to form the above polymer 1 / 2 ).

[0021] Furthermore, the present invention provides a method for producing a polarizing film, the polarizing film comprising an iodine polarizer and a resin layer comprising a polymer having a structural unit derived from a (meth)acrylate.

[0022] The manufacturing method comprises:

[0023] Let y calculated by the following formula (1) 1 A step of polymerizing a monomer having a value of less than 1.3 to obtain the above polymer,

[0024] y 1 =(0.279)x 1 +(-1.51)x 2+(0.178)x 3 +0.386 (1)

[0025] In the above formula (1), x 1 is the number of rotatable bonds contained in the above monomer,

[0026] x 2 is the number of reaction sites contained in the above monomer,

[0027] x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the above monomer 1 / 2 ).

[0028] In addition, the present invention provides a polarizing film comprising:

[0029] A polarizer containing iodine, and

[0030] a resin layer comprising a polymer having a structural unit derived from a (meth)acrylate,

[0031] Here, y calculated by the following formula (2) 2 The value of is less than 1.3,

[0032] y 2 =(0.255)x 1 +(-1.57)x 2 +(0.151)x 3 +(-18.0)x 4 +(0.0987)x 5 +(-8.26) (2)

[0033] In the above formula (2), x 1 is the number of rotatable bonds contained in the monomer used to form the above polymer,

[0034] x 2 is the number of reaction sites contained in the above monomer used to form the above polymer,

[0035] x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the above monomer used to form the above polymer 1 / 2 ),

[0036] x 4 is the charge (C) of the atom with the most negative charge among the atoms functioning as hydrogen bond acceptors in the monomer used to form the polymer,

[0037] x 5 is the x component (Debye) in the dipole moment of the above monomer used to form the above polymer.

[0038] The present invention also provides a method for producing a polarizing film, the polarizing film comprising: a polarizer containing iodine, and a resin layer containing a polymer having a structural unit derived from a (meth)acrylate.

[0039] The manufacturing method comprises:

[0040] Let y calculated by the following formula (2) 2 A step of polymerizing a monomer having a value of less than 1.3 to obtain the above polymer,

[0041] y 2 =(0.255)x 1 +(-1.57)x 2 +(0.151)x 3 +(-18.0)x 4 +(0.0987)x 5 +(-8.26) (2)

[0042] In the above formula (2), x 1 is the number of rotatable bonds contained in the monomer used to form the above polymer,

[0043] x 2 is the number of reaction sites contained in the above monomer used to form the above polymer,

[0044] x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the above monomer used to form the above polymer 1 / 2 ),

[0045] x 4 is the charge (C) of the atom with the most negative charge among the atoms functioning as hydrogen bond acceptors in the monomer used to form the polymer,

[0046] x 5 is the x component (Debye) in the dipole moment of the above monomer used to form the above polymer.

[0047] Effects of the Invention

[0048] According to the present invention, it is possible to provide a polarizing film capable of sufficiently suppressing the transmission of iodine contained in a polarizer to the outside in a high-temperature and high-humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic cross-sectional view of a polarizing film according to one embodiment of the present invention.

[0050] Figure 2 It is a schematic cross-sectional view showing a modified example of the polarizing film.

[0051] Figure 3It is a schematic cross-sectional view showing another modified example of the polarizing film.

[0052] Figure 4 It is a schematic cross-sectional view showing still another modified example of the polarizing film.

[0053] Figure 5 It is a schematic cross-sectional view of an image display device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0054] Hereinafter, the present invention will be described in detail, but the gist of the following description is not to limit the present invention to specific embodiments.

[0055] (Embodiment of Polarizing Film)

[0056] like Figure 1 As shown, the polarizing film 10 of the present embodiment comprises: a polarizer 1 containing iodine, and a resin layer 2 containing a polymer P. The polymer P contained in the resin layer 2 has a structural unit derived from (meth)acrylate. In the present specification, "(meth)acrylic acid" refers to acrylic acid and / or methacrylic acid. The resin layer 2 is, for example, located closer to the visible side than the polarizer 1 and directly in contact with the polarizer 1. However, other layers such as an adhesive layer and an easy-to-bond layer may be arranged between the resin layer 2 and the polarizer 1 within the scope that does not hinder the effect of the present invention. The resin layer 2 may be located closer to the image display panel side described later than the polarizer 1. In other words, the polarizer 1 may be located closer to the visible side than the resin layer 2. The resin layer 2 is, for example, located at the outermost side of the polarizing film 10. It should be noted that in the present specification, "film" refers to a component whose thickness is sufficiently smaller than its length and width.

[0057] The polarizing film 10 may further include an adhesive layer 3, a transparent protective film (first transparent protective film) 4, and an adhesive layer 5. The transparent protective film 4 may be bonded to the polarizer 1 via the adhesive layer 3, for example. The adhesive layer 5 functions as a member for bonding the polarizing film 10 to an image display panel described later, for example. Therefore, the adhesive layer 5 is located, for example, at the outermost side of the polarizing film 10, that is, closer to the image display panel side than the polarizer 1. In other words, the polarizer 1 is located, for example, closer to the visible side than the adhesive layer 5. The resin layer 2, the polarizer 1, the adhesive layer 3, the transparent protective film 4, and the adhesive layer 5 are arranged, for example, in this order in the stacking direction.

[0058] In the polarizing film 10 of the present embodiment, y calculated by the following formula (1) 1 The value of is less than 1.3.

[0059] y 1 =(0.279)x 1 +(-1.51)x 2 +(0.178)x3 +0.386 (1)

[0060] In formula (1), x 1 is the number of rotatable bonds contained in the monomer M used to form the polymer P. 1 It can be used as an indicator for predicting the extent to which the molecular motion of polymer P is restricted. In this specification, "rotatable bond" refers to a single bond connecting heavy atoms, excluding single bonds contained in the ring structure, and single bonds connecting heavy atoms at the end with other heavy atoms. Heavy atoms refer to atoms other than hydrogen atoms and helium atoms, specifically including heteroatoms such as nitrogen atoms and oxygen atoms, and carbon atoms. Specific examples of single bonds connecting heavy atoms are carbon-carbon bonds and carbon-heteroatom bonds. As an example, in the case where polymer P is formed by dihydroxymethyltricyclodecane diacrylate, x 1 The value of is 8. The number of rotatable bonds can be calculated using software for calculating molecular descriptors. Examples of such software include Dragon (version 7.0), alvaDesc, and the like.

[0061] When the polymer P is formed from a plurality of monomers M, x can be determined by the following method: 1 First, the number of rotatable bonds is calculated for each monomer M, and the calculated number of rotatable bonds is weighted according to the molar ratio of each monomer M, and a weighted average is taken. The obtained weighted average value can be regarded as x 1 In this embodiment, x 1 The value of is not particularly limited, and is, for example, 2 to 20.

[0062] x 2 is the number of reactive sites contained in the monomer M used to form the polymer P. 2 It can be used as an index for predicting the extent to which the polymer P has gaps that allow low molecular weight compounds to pass through. In this specification, "reaction point" refers to a polymerizable group or a crosslinkable group. Specific examples of these groups include groups having polymerizable double bonds such as (meth)acryloyl groups, epoxy groups, and crosslinkable functional groups such as oxetane groups. As an example, when the polymer P is formed from dihydroxymethyl tricyclodecane diacrylate, x 2 The value of is 2. The number of reaction sites can be calculated using the software used to calculate the above-mentioned molecular descriptors.

[0063] When the polymer P is formed from a plurality of monomers M, the following method can be used to identify x 2First, the number of reaction points is calculated for each monomer M, and the calculated number of reaction points is weighted according to the molar ratio of each monomer M, and a weighted average is taken. The obtained weighted average value can be regarded as x 2 In this embodiment, x 2 The value of is not particularly limited, and is, for example, 1 to 6.

[0064] x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the monomer M used to form the polymer P 1 / 2 ). 3 It can be used as an indicator for predicting the interaction between polymer P and water molecules or iodine. Hansen solubility parameters refer to parameters that divide the solubility parameters introduced by Hildebrand into three components: dispersion term δD, polar term δP, and hydrogen bond term δH. The polar term δP represents the energy brought by the dipole interaction between molecules. The details of Hansen solubility parameters are disclosed in "Hansen Solubility Parameters; A Users Handbook (CRC Press, 2007)". The polar term δP can be calculated using, for example, well-known software such as HSPiP (version 5). It should be noted that the value of the polar term δP sometimes varies slightly depending on the software used. However, this error is usually calculated. 1 The value of is negligible.

[0065] When the polymer P is formed from a plurality of monomers M, x can be determined by the following method: 3 First, the polar term δP (MPa) in the Hansen solubility parameter was calculated for each monomer M. 1 / 2 ), the calculated polar term δP is weighted according to the molar ratio of each monomer M, and the weighted average is taken. The obtained weighted average can be regarded as x 3 In this embodiment, x 3 The value of is not particularly limited, for example, 1 to 10 (MPa 1 / 2 ). 3 The value is preferably 6 (MPa 1 / 2 ) or less, more preferably 5 (MPa 1 / 2 ) or less, more preferably 4 (MPa 1 / 2 )the following.

[0066] In the polarizing film 10 of the present embodiment, y calculated by the following formula (2) 2 The value of can be less than 1.3.

[0067] y 2 =(0.255)x 1+(-1.57)x 2 +(0.151)x 3 +(-18.0)x 4 +(0.0987)x 5 +(-8.26) (2)

[0068] From another aspect, the present invention provides a polarizing film 10 comprising: a polarizer 1 containing iodine, and a resin layer 2 containing a polymer P having a structural unit derived from a (meth)acrylate, wherein y calculated by formula (2) 2 The value of is less than 1.3.

[0069] In formula (2), x 1 ~x 3 Same as formula (1). Therefore, x in formula (2) 1 ~x 3 The specific method etc. are the same as above.

[0070] In formula (2), x 4 It is the charge (C) of the atom with the most negative charge among the atoms functioning as hydrogen bond acceptors in the monomer M used to form the polymer P. 4 It can be used as an index for predicting the interaction between polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity of polymer P. 4 The closer the value of is to 0, the more likely the polymer P is to be hydrophobic. A hydrogen bond acceptor is an atom that can form a hydrogen bond with a hydrogen atom contained in a water molecule. Atoms that function as hydrogen bond acceptors include atoms with relatively large electronegativity such as oxygen atoms and nitrogen atoms.

[0071] x 4 For example, the following method can be used to identify the monomer M used to form the polymer P. By performing molecular simulation on the monomer M, the charge (Mulliken charge) of each atom constituting the monomer M can be calculated. Molecular simulation can be performed using, for example, Materials Studio (manufactured by BIOVIA, ver. 8.0.0.843) or WebMO (ver. 19.0.009e).

[0072] Molecular simulation can be performed, for example, by the following method. First, a molecular model of monomer M is prepared using Materials Studio. Regarding the molecular model, the force field of COMPASS (Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies) II is used to optimize the structure. Next, the molecular model of monomer M is processed using WebMO. In detail, in WebMO, the Gaussian program (Queue: g09) is used to perform structural optimization calculations on the molecular model of monomer M. At this time, B3LYP can be used as a universal function, and 6-31G (d) can be used as a basis function. Through the above molecular simulation, the charge of each atom constituting monomer M can be calculated.

[0073] Next, the atom that functions as a hydrogen bond acceptor is identified among the atoms constituting the monomer M. Furthermore, the atom with the most negative charge (the atom having a negative charge and the largest absolute value of its charge) is identified from among the identified atoms, and the charge (C) of the atom can be regarded as x 4 It should be noted that, when the monomer M does not have an atom that functions as a hydrogen bond acceptor, x 4 Can be considered as 0.

[0074] When the polymer P is formed from a plurality of monomers M, the following method can be used to identify x 4 First, the charge (C) of the atom with the most negative charge among the atoms that function as hydrogen bond acceptors is specified for each of the multiple monomers M by the above method, and the specified charges are weighted according to the molar ratio of each monomer M, and the weighted average is taken. The obtained weighted average can be regarded as x 4 When the multiple monomers M are structural isomers, the specific charges can be weighted according to the molar ratio of each structural isomer and the weighted average can be taken to specify x. 4 In this embodiment, x 4 The value of is not particularly limited, and is, for example, -0.55 to -0.45C.

[0075] x 5 is the x component of the dipole moment of the monomer M used to form the polymer P (Debye). 5 It can be used as an index for predicting the interaction between the polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity and humidification durability of the polymer P. 5 The closer the value of is to 0, the smaller the dipole moment of the monomer M is, and the more likely the polymer P is to be hydrophobic.

[0076] x 5 For example, the following method can be used to identify the monomer M used to form the polymer P. By performing molecular simulation on the monomer M, the x component in the dipole moment can be calculated. Molecular simulation can be performed by the above x component. 4 When performing molecular simulation, the internal coordinates of each atom constituting the monomer M are defined in the form of a Z-matrix. When the Z-matrix form is used, the x-axis, y-axis, and z-axis used to determine the internal coordinates are automatically determined according to the structure of the monomer M. It should be noted that the dipole moment is a vector calculated from the x-component, the y-component, and the z-component.

[0077] When the polymer P is formed from a plurality of monomers M, the following method can be used to identify x 5 First, the x component in the dipole moment of the various monomers M is calculated by the above method, and the x component in the calculated dipole moment is weighted according to the molar ratio of each monomer M, and a weighted average is performed. The obtained weighted average value can be regarded as x 5 When the plurality of monomers M are structural isomers, the x component in the calculated dipole moment may be weighted according to the molar ratio of each structural isomer and the weighted average may be taken to thereby specify x. 5 In this embodiment, x 5 The value of is not particularly limited, and is, for example, -2.0 to 5.0 Debye. 5 The value of can be less than 3.0 Debye or less than 1.0 Debye.

[0078] y calculated by formula (1) 1 The value of , and y calculated by formula (2) 2 The value of is preferably 0.8 or less, more preferably 0.7 or less, further preferably 0.5 or less, and particularly preferably 0.3 or less.

[0079] The y calculated by formula (1) 1 The value of , and y calculated by formula (2) 2 The value of is an index related to the monomer M contained in the resin layer 2 for forming the polymer P. However, according to the research of the present inventors, y 1 The value of y 2 The value of y is also useful as an index for selecting a resin layer 2 suitable for suppressing the transmission of iodine contained in the polarizer 1 to the outside. 2 The factor (x 1 ~x 5 ) is greater than the number used to calculate y 1 The factor (x 1 ~x3 Generally speaking, the number of factors tends to affect the prediction performance of the prediction formula.

[0080] In the polarizing film 10 of the present embodiment, for example, at least one of the following requirements (i) to (v) is satisfied, and preferably the requirement (iii) is satisfied. In the polarizing film 10, all of the requirements (i) to (v) may be satisfied.

[0081] (i) The tensile modulus E1 of the resin layer 2 in 65°C water is 1×10 8 Pa or above.

[0082] (ii) The tensile modulus E2 of the resin layer 2 in 85°C water is 1×10 8 Pa or above.

[0083] (iii) When the resin layer 2 is heated from 25°C to 65°C and the measurement atmosphere is humidified from 10%RH to 90%RH, the linear expansion coefficient α1 of the resin layer 2 is 400×10 -6 / K or less.

[0084] (iv) When the resin layer 2 is heated from 25°C to 85°C and the measurement atmosphere is humidified from 10%RH to 85%RH, the linear expansion coefficient α2 of the resin layer 2 is 300×10 -6 / K or less.

[0085] (v) The dipole moment D of the monomer M for forming the polymer P contained in the resin layer 2 is 2 Debye or less.

[0086] First, requirement (i) will be described. The tensile modulus E1 of the resin layer 2 is preferably 5×10 8 Pa or more, more preferably 10×10 8 Pa or more, more preferably 15×10 8 The upper limit of the tensile modulus E1 is not particularly limited, but from the viewpoint of suppressing cracks in the resin layer 2, it may be, for example, 100×10 8 Pa.

[0087] The tensile modulus E1 of the resin layer 2 can be measured, for example, by the following method. First, the resin layer 2 to be evaluated is cut into a strip with a width of 5 mm and a length of 30 mm as a test piece. Next, the test piece is placed in a commercially available dynamic viscoelasticity measuring device. At this time, as a clamp, a clamp that allows the test piece to be immersed in a solvent is used. The distance between the clamps that fix the test piece is set to 15 mm. Next, the test piece is immersed in water. After confirming that the temperature of the test piece is 25°C, the dynamic viscoelasticity measurement of the test piece is started. The measurement is carried out according to the tensile vibration-non-resonance method specified in Japanese Industrial Standard (JIS) K7244-4:1999. The frequency of the vibration is set to 1 Hz. After starting the measurement, the test piece is heated to 95°C at a heating rate of 5°C / min. The measured value of the tensile modulus when the temperature of the test piece is 65°C can be regarded as the tensile modulus E1 of the resin layer 2.

[0088] Next, requirement (ii) will be described. The tensile modulus E2 of the resin layer 2 is preferably 5×10 8 Pa or more, more preferably 10×10 8 Pa or more, more preferably 15×10 8 The upper limit of the tensile modulus E2 is not particularly limited, but from the viewpoint of suppressing cracks in the resin layer 2, it can be, for example, 100×10 8 The tensile modulus E2 of the resin layer 2 can be measured, for example, by the same method as the tensile modulus E1. Specifically, the dynamic viscoelasticity of the test piece is measured by the method described above for the tensile modulus E1, and the measured value of the tensile modulus when the temperature of the test piece is 85°C can be regarded as the tensile modulus E2 of the resin layer 2.

[0089] Next, requirement (iii) will be described. The linear expansion coefficient α1 of the resin layer 2 is preferably 200×10 -6 / K or less, more preferably 180×10 -6 / K or less, more preferably 150×10 -6 / K or less, particularly preferably 120×10 -6 The lower limit of the linear expansion coefficient α1 is not particularly limited, but from the viewpoint of suppressing cracks in the resin layer 2, it may be, for example, 10×10 -6 / K.

[0090] The linear expansion coefficient α1 of the resin layer 2 can be measured, for example, by the following method. First, the resin layer 2 to be evaluated is cut into a strip with a width of 5 mm and a length of 30 mm as a test piece. Next, the test piece is placed in a commercially available thermomechanical analysis device. At this time, the distance between the clamps that fix the test piece is set to 15 mm. The test piece is placed in a measurement atmosphere of 25°C and 10% RH for at least 10 minutes. Next, the test piece is heated to 65°C over 60 minutes, and the test piece is kept for 10 minutes. Next, the measurement atmosphere is humidified from 10% RH to 90% RH over 30 minutes, and the test piece is kept for 10 minutes. The linear expansion coefficient α calculated based on the change in length ΔL (mm) of the test piece before and after the test according to the following formula (3) can be regarded as the linear expansion coefficient α1 of the resin layer 2. It should be noted that in formula (3), L 0 It refers to the length of the test piece at 25°C, and ΔT refers to the change in temperature of the test piece before and after the test. In requirement (iii), ΔT is 40°C.

[0091] Linear expansion coefficient α=ΔL / (L 0 ×ΔT) (3)

[0092] Next, requirement (iv) will be described. The linear expansion coefficient α2 of the resin layer 2 is preferably 200×10 -6 / K or less, more preferably 170×10 -6 / K or less, more preferably 150×10 -6 / K or less, particularly preferably 100×10 -6 The lower limit of the linear expansion coefficient α2 is not particularly limited, but from the viewpoint of suppressing cracks in the resin layer 2, it may be, for example, 10×10 -6 / K. The linear expansion coefficient α2 of the resin layer 2 is measured by the same method as the linear expansion coefficient α1, for example, except that the test piece is heated to 85°C for 60 minutes and the measurement atmosphere is humidified from 10% RH to 85% RH for 30 minutes. In the requirement (iv), ΔT in the above formula (3) is 60°C.

[0093] Next, requirement (v) is described. The dipole moment D of the monomer M used to form the polymer P is preferably 1.7 Debye or less, more preferably 1.5 Debye or less, and even more preferably 1.3 Debye or less. The lower limit of the dipole moment D is not particularly limited, and is, for example, 0.5 Debye.

[0094] The dipole moment D can be calculated, for example, by the following method. First, the monomer M used to form the polymer P is identified. The dipole moment D can be calculated by performing molecular simulation on the monomer M. Molecular simulation can be performed using, for example, known software such as Materials Studio (manufactured by BIOVIA, ver. 8.0.0.843) and WebMO (ver. 19.0.009e).

[0095] The calculation of the dipole moment D using molecular simulation can be performed, for example, by the following method. First, using Materials Studio, a molecular model of monomer M is made. Regarding the molecular model, the force field of COMPASS (Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies) II is used to optimize the structure. Next, the molecular model of monomer M is processed using WebMO. In detail, in WebMO, the Gaussian program (Queue: g09) is used to perform structural optimization calculations on the molecular model of monomer M. At this time, B3LYP can be used as a universal function, and 6-31G (d) can be used as a basis function. The dipole moment D of monomer M can thus be calculated.

[0096] When the polymer P is formed from a plurality of monomers M, the dipole moment D can be specified by the following method. First, the dipole moments of the plurality of monomers M are calculated by the above method, the calculated dipole moments are weighted according to the molar ratio of each monomer M, and a weighted average is taken, and the obtained weighted average value can be regarded as the dipole moment D. When the plurality of monomers M are structural isomers, the calculated dipole moments can also be weighted according to the molar ratio of each structural isomer, and a weighted average is taken to calculate the dipole moment D.

[0097] When at least one of the requirements (i) and (ii) is satisfied, the polymer P contained in the resin layer 2 tends to maintain a state of low molecular mobility even in a high temperature and high humidity environment. If the molecular mobility of the polymer P is low, it is difficult to generate a space into which iodine can penetrate in the resin layer 2. As a result, the movement of iodine from the polarizer 1 to the resin layer 2 is suppressed, and there is a tendency to suppress the transmission of iodine to the outside of the polarizing film 10.

[0098] When at least one of the requirements (iii) and (iv) is satisfied, the polymer P contained in the resin layer 2 tends to maintain a small free volume even in a high temperature and high humidity environment. If the free volume of the polymer P is small, it is difficult to generate a space in the resin layer 2 into which iodine can penetrate. As a result, the movement of iodine from the polarizer 1 to the resin layer 2 is suppressed, and there is a tendency to suppress the transmission of iodine to the outside of the polarizing film 10.

[0099] When requirement (v) is satisfied, electrostatic interaction tends to be less likely to occur between the polymer P and iodine. That is, iodine is less likely to be attracted to the polymer P. As a result, the movement of iodine from the polarizer 1 to the resin layer 2 is suppressed, and the transmission of iodine to the outside of the polarizing film 10 tends to be suppressed.

[0100] [Polarizing filter]

[0101] The polarizer 1 is not particularly limited as long as it contains iodine, and examples thereof include polarizers obtained by adsorbing iodine on a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or a partially saponified film of an ethylene-vinyl acetate copolymer, and then uniaxially stretching the film. The polarizer 1 is preferably composed of a polyvinyl alcohol film and iodine.

[0102] The thickness of the polarizer 1 is not particularly limited, for example, it is 30 μm or less, preferably 20 μm or less, more preferably 18 μm or less, further preferably 15 μm or less, particularly preferably 12 μm or less, and particularly preferably 10 μm or less. The thickness of the polarizer 1 may be 2 μm or more, 4 μm or more, or 5 μm or more. The thickness of the polarizer 1 may be 7 to 12 μm, and may be 1 to 7 μm depending on the circumstances, and may be 4 to 6 μm in particular. In this specification, a polarizer 1 having a thickness of 10 μm or less is sometimes referred to as a thin polarizer. Thin polarizers tend to have less uneven thickness and excellent visual recognition. In addition, thin polarizers also have the advantages of suppressing dimensional changes and excellent durability. By using a thin polarizer, the polarizing film 10 can be thinned. In the case where the polarizer 1 is a thin polarizer, in order to make the polarizing film 10 have a sufficient degree of polarization for practical use, the concentration of iodine in the polarizer 1 must be adjusted to a higher level. The polarizing film 10 of the present embodiment can sufficiently suppress the transmission of iodine from the polarizer 1 to the outside even when the thickness of the polarizer 1 is small and the concentration of iodine in the polarizer 1 is high.

[0103] The polarizer 1 can be made, for example, by immersing a hydrophilic polymer film such as a polyvinyl alcohol film in an aqueous solution of iodine to dye it, and stretching it to 3 to 7 times its original length. If necessary, the hydrophilic polymer film can also be immersed in an aqueous solution containing boric acid, potassium iodide, etc. Further, the hydrophilic polymer film can be immersed in water and washed before dyeing as needed. By washing the hydrophilic polymer film with water, dirt and anti-adhesion agents attached to the surface can be washed away. If the hydrophilic polymer film is washed with water, the hydrophilic polymer film swells, so it also has the effect of suppressing uneven dyeing. The stretching of the hydrophilic polymer film can be carried out after dyeing with iodine, it can be carried out while dyeing, or it can be carried out before dyeing with iodine. The stretching of the hydrophilic polymer film can be carried out in an aqueous solution containing boric acid, potassium iodide, etc., or in water.

[0104] As thin polarizers, representative examples include those described in Japanese Patent Application Laid-Open No. 51-069644, Japanese Patent Application Laid-Open No. 2000-338329, International Publication No. 2010 / 100917, Japanese Patent Application Laid-Open No. 2014-59328, Japanese Patent Application Laid-Open No. 2012-73563, etc. These thin polarizers can be produced by a manufacturing method including a step of stretching a laminate comprising a polyvinyl alcohol resin (PVA resin) layer and a stretching resin substrate, and a step of dyeing the obtained stretched film. In this manufacturing method, since the PVA resin layer is supported by the stretching resin substrate, defects such as breakage caused by stretching are not easily generated.

[0105] For thin polarizers, from the viewpoint of being able to stretch at a high ratio and improving polarization performance, in the above-mentioned manufacturing method, it is preferably made by a manufacturing method including a stretching process in a boric acid aqueous solution, and particularly preferably made by a manufacturing method including a process of stretching in an auxiliary gas atmosphere before the stretching process in a boric acid aqueous solution. The manufacturing method including a stretching process in a boric acid aqueous solution is disclosed in International Publication No. 2010 / 100917, Japanese Patent Publication No. 2014-59328, Japanese Patent Publication No. 2012-73563, etc. The manufacturing method including a process of stretching in a gas atmosphere is disclosed in Japanese Patent Publication No. 2014-59328, Japanese Patent Publication No. 2012-73563, etc.

[0106] [Resin layer]

[0107] As long as the polymer P has a structural unit derived from a (meth)acrylate and y calculated by the above formula (1) is 1 The value of y, or the value of y calculated by formula (2) 2When the value of is less than 1.3, the resin layer 2 and the polymer P contained in the resin layer 2 are not particularly limited.

[0108] The (meth)acrylate may be a monofunctional (meth)acrylate having one (meth)acryloyl group, or may be a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups. The polymer P preferably contains a structural unit derived from the polyfunctional (meth)acrylate. According to the polymer P containing a structural unit derived from the polyfunctional (meth)acrylate, there is a tendency to further suppress the movement of iodine from the polarizer 1 to the resin layer 2. The number of (meth)acryloyl groups contained in the polyfunctional (meth)acrylate is not particularly limited, and is, for example, 2 to 6, preferably 2 to 4. When the number of (meth)acryloyl groups contained in the polyfunctional (meth)acrylate is too large, unreacted (meth)acryloyl groups may remain in the polymer P.

[0109] The number of carbon atoms in the part other than the (meth)acryloyl group in the (meth)acrylate (hereinafter sometimes referred to as the ester part) is not particularly limited, and is, for example, 1 to 18, preferably 4 to 10. The ester part may contain a ring structure. The ring structure may contain heteroatoms such as nitrogen atoms and oxygen atoms, and preferably contains only alicyclic hydrocarbons. The ring structure may be a condensed ring structure such as tricyclodecane, or a monocyclic structure such as cyclohexane. In addition, the ring structure may also be a lactone ring. The ester part may contain functional groups such as ether groups.

[0110] (Meth)acrylate may contain a polar group, but preferably does not contain a polar group. In this specification, a polar group refers to a group containing a bond formed by a hydrogen atom and a heteroatom such as an oxygen atom or a nitrogen atom. Examples of the polar group include a hydroxyl group, a carboxyl group, a primary amino group, and a secondary amino group.

[0111] Examples of the (meth)acrylate include dicyclopentanyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, lauryl (meth)acrylate, 5-(meth)acryloyloxy-2,6-norbornyl lactone, 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tert-butylphenyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, 2-isopropyl-2-adamantyl (meth)acrylate, 4-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, 1-naphthyl (meth)acrylate, and 2-naphthyl (meth)acrylate. -anthracene ester, 1-anthracenemethyl (meth)acrylate, 9-anthracenemethyl (meth)acrylate and other monofunctional (meth)acrylates; dihydroxymethyltricyclodecane di(meth)acrylate, 1,3-adamantanediol di(meth)acrylate, 1,3,5-adamantanediol-1,5-di(meth)acrylate, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene and other bifunctional (meth)acrylates; trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, 1,3,5-adamantanediol tri(meth)acrylate and other trifunctional (meth)acrylates; pentaerythritol tetra(meth)acrylate and other quadrifunctional (meth)acrylates; dipentaerythritol hexa(meth)acrylate and other hexafunctional (meth)acrylates, etc.

[0112] The polymer P preferably contains a structural unit derived from a (meth)acrylate as a main component, and preferably consists essentially of a structural unit derived from a (meth)acrylate. In the present specification, the "main component" refers to a structural unit that is contained in the largest amount on a weight basis in the polymer P. The content of the structural unit derived from a (meth)acrylate in the polymer P is, for example, 50% by weight or more, preferably higher than 70% by weight, more preferably 80% by weight or more, further preferably 90% by weight or more, particularly preferably 95% by weight or more, and particularly preferably 99% by weight or more.

[0113] The polymer P may further include a structural unit derived from a radical polymerizable monomer other than (meth)acrylate, or a structural unit derived from an anionic polymerizable monomer other than (meth)acrylate. In addition, the polymer P may include a structural unit derived from a cationically polymerizable monomer.

[0114] As other free radical polymerizable monomers other than (meth)acrylate, styrene compounds can be mentioned. Styrene compounds, for example, contain an aromatic ring and one or more vinyl groups. Like (meth)acrylate, styrene compounds can also contain polar groups, but preferably do not contain polar groups. Examples of styrene compounds include styrene, α-methylstyrene, vinylbenzyl chloride, butoxystyrene, vinylpyridine, etc.

[0115] Examples of cationic polymerizable monomers include vinyl ether compounds, epoxy compounds, and oxetane compounds. Examples of vinyl ether compounds include aliphatic vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether; aromatic vinyl ethers such as phenyl vinyl ether, 2-phenoxyethyl vinyl ether, and p-methoxyphenyl vinyl ether; and polyfunctional vinyl ethers such as butanediol-1,4-divinyl ether, triethylene glycol divinyl ether, and dipropylene glycol divinyl ether.

[0116] Examples of epoxy compounds include aromatic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Examples of aromatic epoxy compounds include diglycidyl ether compounds (bisphenol-type epoxy resins) of bisphenols such as bisphenol A, bisphenol F, and bisphenol S; novolac-type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, and hydroxybenzaldehyde phenol novolac epoxy resins; and glycidyl ether compounds of polyols such as tetrahydroxyphenylmethane, tetrahydroxybenzophenone, and polyvinylphenol.

[0117] Examples of the alicyclic epoxy compound include vinyl cyclohexene oxide, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, limonene dioxide, bis(3,4-epoxycyclohexylmethyl)adipate, dicyclopentadiene diepoxide, dicyclononadiene diepoxide, tricyclopentadiene diepoxide, and dodecahydro-2,6-methano-2H-oxiranyl[3',4']cyclopenta[1',2':6,7]naphtho[2,3-b]oxirane.

[0118] Examples of the aliphatic epoxy compound include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and polyethylene glycol diglycidyl ether.

[0119] Examples of the oxetane compound include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyl-3-oxetanyl)methyl]ether, and 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane.

[0120] The polymer P preferably contains structural units derived from a multifunctional monomer. Examples of the multifunctional monomer include: the above-mentioned multifunctional (meth) acrylates, multifunctional vinyl ether compounds, multifunctional epoxy compounds, multifunctional oxetane compounds, etc. The content of structural units derived from multifunctional monomers in the polymer P is, for example, 20% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more, and may be 70% by weight or more depending on the circumstances. The upper limit of the content of structural units derived from multifunctional monomers is not particularly limited, and is, for example, 95% by weight.

[0121] The polymer P may contain a structural unit derived from a monomer having a polar group, but preferably does not contain the structural unit. In the case where the polymer P contains a structural unit derived from a monomer having a polar group, there is a tendency for iodine contained in the polarizer 1 to easily approach the resin layer 2. Therefore, the content of the structural unit derived from a monomer having a polar group in the polymer P is preferably 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, and particularly preferably 2% by weight or less.

[0122] The resin layer 2 contains, for example, a polymer P as a main component. The content of the polymer P in the resin layer 2 is, for example, 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more. The resin layer 2 preferably contains substantially only the polymer P. However, the resin layer 2 may contain additives such as an antistatic agent, an antioxidant, inorganic particles, and a leveling agent in addition to the polymer P.

[0123] The thickness of the resin layer 2 is not particularly limited, and is, for example, 10 μm or less, preferably 5 μm or less, and more preferably 3 μm or less. From the viewpoint of sufficiently suppressing the transmission of iodine contained in the polarizer 1 to the outside, the thickness of the resin layer 2 is preferably 0.3 μm or more, and may be 0.5 μm or more.

[0124] The resin layer 2 can be bonded to the polarizer 1 via an adhesive layer or an easy-bonding layer. As the adhesive layer for bonding the resin layer 2 to the polarizer 1, for example, those exemplified for the adhesive layer 3 described later can be cited. The easy-bonding layer can be formed, for example, by a resin containing a polymer having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. The polymer contained in the resin can be one kind or two or more kinds. The easy-bonding layer can contain additives. As additives, stabilizers such as adhesion imparting agents, ultraviolet absorbers, antioxidants, and heat-resistant stabilizers can be cited. The thickness of the easy-bonding layer is not particularly limited, and is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. The easy-bonding layer can be a multi-layer laminate.

[0125] [Adhesive layer]

[0126] The adhesive layer 3 is a layer containing an adhesive. The material of the adhesive is not particularly limited, and a known material can be used. As the adhesive contained in the adhesive layer 3, for example, there can be mentioned: an aqueous adhesive and an active energy ray-curable adhesive. As the active energy ray-curable adhesive, for example, those disclosed in Japanese Patent Application Laid-Open No. 2019-147865, Japanese Patent Application Laid-Open No. 2016-177248, etc. can be used.

[0127] The thickness of the adhesive layer 3 is not particularly limited, and is, for example, 3.0 μm or less, preferably 0.01 to 3.0 μm, more preferably 0.1 to 2.5 μm, and further preferably 0.5 to 1.5 μm. When the thickness of the adhesive layer 3 is too small, the cohesive force of the adhesive layer 3 is sometimes insufficient and the peeling force is reduced. When the thickness of the adhesive layer 3 is too large, if stress is applied to the cross section of the polarizing film 10, peeling may sometimes occur in the adhesive layer 3. That is, in the polarizing film 10, peeling failure caused by impact may sometimes occur.

[0128] [Transparent protective film]

[0129] As the transparent protective film 4, it is preferred that the transparent protective film 4 has excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. As the material of the transparent protective film 4, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as cellulose diacetate and cellulose triacetate; (meth) acrylic polymers such as polymethyl methacrylate; styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); polycarbonate polymers; olefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymer; cyclic olefin polymers such as polynorbornene; vinyl chloride polymers; amide polymers such as nylon and aromatic polyamide; imide polymers; sulfone polymers; polyethersulfone polymers; polyetheretherketone polymers; polyphenylene sulfide polymers; vinyl alcohol polymers; vinylidene chloride polymers; vinyl butyral polymers; polyarylate polymers; polyoxymethylene polymers; epoxy polymers; mixtures of these polymers, etc.

[0130] The transparent protective film 4 preferably contains a polymer that functions as a thermoplastic resin among the above-mentioned polymers. The content of the thermoplastic resin in the transparent protective film 4 is preferably 50% to 100% by weight, more preferably 50% to 99% by weight, further preferably 60% to 98% by weight, and particularly preferably 70% to 97% by weight. When the content of the thermoplastic resin in the transparent protective film 4 is less than 50% by weight, the functions such as high transparency that the thermoplastic resin originally has may not be fully exhibited.

[0131] The transparent protective film may contain one or more additives, such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

[0132] The transparent protective film 4 can be a polymer film described in Japanese Patent Gazette No. 2001-343529, International Publication No. 01 / 37007, etc. As the material of the polymer film, for example, a resin composition comprising a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and a thermoplastic resin having a substituted and / or unsubstituted phenyl and nitrile group in the side chain can be cited. As a specific example of the polymer film, a film formed by a resin composition can be cited, and the resin composition includes an alternating copolymer formed by isobutylene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The film can be obtained, for example, by mixing and extruding the resin composition. The film has a small phase difference and a small photoelastic coefficient, so it can eliminate the unevenness caused by the strain of the polarizing film 10. In addition, the film has a low moisture permeability, so it has excellent durability in a humid environment.

[0133] The moisture permeability of the transparent protective film 4 is not particularly limited, but is preferably 150 g / m2 / 24h or less. In this case, it is possible to suppress the moisture in the air from invading the interior of the polarizing film 10, and it is possible to suppress the change in the moisture content of the polarizing film 10. As a result, during storage, the curling and dimensional changes of the polarizing film 10 can be suppressed. As a material for forming the transparent protective film 4 with low moisture permeability, for example, there can be mentioned: polyester polymers, polycarbonate polymers, polyarylate polymers, amide polymers, olefin polymers, cyclic olefin polymers, (meth)acrylic polymers, and mixtures thereof. As a material for forming the transparent protective film 4, polycarbonate polymers, cyclic olefin polymers and (meth)acrylic polymers are preferred, and cyclic olefin polymers and (meth)acrylic polymers are particularly preferred.

[0134] The thickness of the transparent protective film 4 is not particularly limited, but is preferably 5 to 100 μm, more preferably 10 to 60 μm, and even more preferably 13 to 40 μm from the viewpoint of strength, handling properties, and the like.

[0135] In order to improve the adhesion between the components, the surface of the transparent protective film 4 may be subjected to an adhesion-facilitating treatment such as corona treatment or plasma treatment. An adhesion-facilitating layer may be disposed on the surface of the transparent protective film 4. As the adhesion-facilitating layer, the adhesion-facilitating layer described above for the resin layer 2 may be used.

[0136] [Adhesive layer]

[0137] The adhesive layer 5 is a layer containing an adhesive. The material of the adhesive is not particularly limited, and for example, a material containing a (meth) acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine polymer, a rubber polymer, etc. as a base polymer can be used. In particular, an acrylic adhesive containing a (meth) acrylic polymer is suitable for the material of the adhesive layer 5 because it has excellent optical transparency, has appropriate adhesive properties such as wettability, cohesion, and adhesion, and is excellent in weather resistance, heat resistance, etc.

[0138] The adhesive layer 5 may be a laminate of multiple layers having different compositions. The thickness of the adhesive layer 5 may be appropriately determined according to the intended use, adhesive strength, etc., and is, for example, 1 to 500 μm, preferably 1 to 200 μm, and more preferably 1 to 100 μm. The thickness of the adhesive layer 5 may be 50 μm or less.

[0139] Before the polarizing film 10 is attached to the image display panel, the adhesive layer 5 may be attached to a separator. The separator can prevent contamination of the adhesive layer 5. As the separator, for example, a film obtained by coating a plastic film, a rubber sheet, paper, a cloth, a nonwoven fabric, a net, a foam sheet, a metal foil, and a laminate thereof with a release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide as needed can be used.

[0140] [Other components]

[0141] The polarizing film 10 may further include other components in addition to the above-mentioned components. For example, the polarizing film 10 may further include a transparent substrate located closer to the visible side than the resin layer 2. The transparent substrate may be located at the outermost side of the polarizing film 10. The transparent substrate is made of, for example, glass or a polymer. Examples of polymers constituting the transparent substrate include polyethylene terephthalate, polycycloolefin, polycarbonate, and the like. The thickness of the transparent substrate made of glass is, for example, 0.1 mm to 1 mm. The thickness of the transparent substrate made of a polymer is, for example, 10 μm to 200 μm.

[0142] The transparent substrate is bonded to the resin layer 2 via an OCA (optical clear adhesive) layer, for example. As the OCA layer, for example, the OCA layer described above for the adhesive layer 5 can be used. The thickness of the OCA layer is preferably 150 μm or less.

[0143] The polarizing film 10 may further include an optical film such as a reflector, a reflective plate, a phase difference film, a viewing angle compensation film, and a brightness enhancement film. The phase difference film includes, for example, a 1 / 2 wave plate, a 1 / 4 wave plate, etc. In the polarizing film 10, the phase difference film may be arranged closer to the image display panel side than the polarizer 1 (for example, between the adhesive layer 5 and the transparent protective film 4), or may be arranged closer to the visible side than the polarizer 1.

[0144] The polarizing film 10 may further include functional layers such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer, and an anti-glare layer. In the polarizing film 10 , the hard coat layer may be disposed closer to the visible side than the resin layer 2 .

[0145] [Polarizing film manufacturing method]

[0146] The method for producing the polarizing film 10 is not particularly limited, and includes, for example, making y calculated by the above formula (1) 1 The step of polymerizing a monomer M having a value of less than 1.3 to obtain a polymer P. The method for producing the polarizing film 10 may include making y calculated by the above formula (2) 2 The above process can be replaced by a process of polymerizing a monomer M having a value of less than 1.3 to obtain a polymer P. In detail, the polarizing film 10 can be manufactured by the following method. First, the polarizer 1 and the transparent protective film 4 are bonded via the adhesive layer 3. Next, a coating solution containing the above-mentioned monomer M and a polymerization initiator is prepared. The polymerization initiator can be appropriately selected according to the monomer M contained in the coating solution. The polymerization initiator is preferably a photopolymerization initiator. In the case where the coating solution contains a cationic polymerizable monomer, a photoacid generator can also be used as a polymerization initiator.

[0147] Examples of the photopolymerization initiator include benzophenone compounds such as benzil, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α′-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α-hydroxycyclohexylphenylketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one; benzoin methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisole methyl ether; aromatic ketal compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphine oxides; acylphosphonates, etc.

[0148] Examples of the photoacid generator include compounds represented by the following formula (i).

[0149] L + X - (i)

[0150] In formula (i), L + for Cation, X - is a counter anion selected from PF 6 - , SbF 6 - , AsF 6 - 、SbCl 6 - 、BiCl 5 - SnCl 6 - , ClO 4 - , dithiocarbamate anions and SCN - .

[0151] Specific examples of the photoacid generator include: "CYRACURE UVI-6992", "CYRACURE UVI-6974" (above, manufactured by Dow Chemical Japan Limited), "Adekaoptomer SP150", "Adekaoptomer SP152", "Adekaoptomer SP170", "Adekaoptomer SP172" (above, manufactured by ADEKA Co., Ltd.), "IRGACURE 250" (manufactured by Ciba Specialty Chemicals Inc.), "CI-5102", "CI-2855" (above, manufactured by Nippon Soda Co., Ltd.), "San-Aid SI-60L", "San-Aid SI-80L", "San-Aid SI-100L", "San-Aid SI-110L", "San-Aid SI-180L" (above, manufactured by Sanshin Chemical Co., Ltd.), "CPI-100P", "CPI-100A" (above, manufactured by San-Apro Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (the above, manufactured by Wako Pure Chemical Industries, Ltd.).

[0152] The content of the polymerization initiator in the coating liquid is, for example, 20% by weight or less, preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and further preferably 0.1 to 5% by weight.

[0153] Next, the coating liquid is applied on the polarizer 1. Thus, a film (coating film) containing a monomer M and a polymerization initiator can be formed on the polarizer 1. Next, the monomer M is polymerized to form a resin layer 2 from the coating film. The polymerization of the monomer M can be carried out by a known method. For example, in the case of using a photopolymerization initiator or a photoacid generator as a polymerization initiator, the monomer M can be polymerized by irradiating the coating film with active energy rays. As active energy rays, for example, visible light and ultraviolet rays can be mentioned. In this specification, the resin layer 2 produced by polymerizing the monomer M contained in the coating film is sometimes referred to as a cured resin layer. Next, the polarizing film 10 is obtained by bonding the adhesive layer 5 to the transparent protective film 4.

[0154] The resin layer 2 can be prepared by the following method. First, the monomer M is polymerized to obtain a polymer P. The obtained polymer P is added to a solvent to prepare a coating liquid. As the solvent, for example, an organic solvent that can dissolve or disperse the polymer P can be cited. Next, the coating liquid is applied to the polarizer 1 to prepare a coating film. The resin layer 2 is obtained by drying the coating film.

[0155] [Characteristics of polarizing film]

[0156] In the polarizing film 10 of the present embodiment, the iodine contained in the polarizer 1 is sufficiently suppressed from being transmitted to the outside in a high temperature and high humidity environment. That is, in a high temperature and high humidity environment, the concentration of iodine in the polarizer 1 hardly changes. The change in the concentration of iodine in the polarizer 1 can be inferred, for example, from the change in the single transmittance of the polarizing film 10. As an example, when the polarizing film 10 is bonded to an alkali-free glass via the adhesive layer 5 and the polarizing film 10 is placed in an atmosphere of 65°C and 90% RH for 24 hours, the change ΔY1 of the single transmittance of the polarizing film 10 is, for example, less than 5, preferably less than 4, more preferably less than 2, further preferably less than 1.5, and particularly preferably less than 1.

[0157] Specifically, the change in single transmittance ΔY1 can be measured by the following method. First, the polarizing film 10 is bonded to the alkali-free glass via the adhesive layer 5 to obtain a laminate, and the single transmittance Ts1 of the obtained laminate is measured. Next, the laminate is placed in an atmosphere of 65°C and 90% RH for 24 hours. The single transmittance Ts2 of the laminate after being placed in the atmosphere is measured. The value obtained by subtracting the single transmittance Ts1 from the single transmittance Ts2 is regarded as the change in single transmittance ΔY1. It should be noted that the single transmittance of the laminate is the Y value obtained by correcting the visibility by the 2-degree field of view (C light source) of JIS Z8701-1999. The single transmittance can be measured using a commercially available spectrophotometer such as DOT-3 manufactured by Murakami Color Technology Research Institute. The measurement wavelength of the single transmittance is 380 to 700 nm (10 nm intervals). Alkali-free glass is glass that does not substantially contain alkali components (alkali metal oxides), and specifically, the weight ratio of alkali components in the glass is, for example, 1000 ppm or less, and further, 500 ppm or less. Alkali-free glass is, for example, in a plate shape and has a thickness of 0.5 mm or more.

[0158] The single transmittance Ts1 is not particularly limited, and is, for example, 42% to 46%, preferably 43% or more, and more preferably 44% or more. The single transmittance Ts2 is not particularly limited, and is, for example, 42% to 48%, preferably 47% or less, and more preferably 46% or less.

[0159] (Modification of Polarizing Film)

[0160] In the polarizing film 10, the resin layer 2 may be located closer to the image display panel described later than the polarizer 1. Figure 2 As shown, in the polarizing film 11 of this modification, the resin layer 2 is located closer to the image display panel side than the polarizer 1. Except for the position of the resin layer 2, the structure of the polarizing film 11 is the same as the structure of the polarizing film 10. Therefore, the same reference symbols are marked for the common elements in the polarizing film 10 and the polarizing film 11 of the modification, and their descriptions are sometimes omitted. That is, the descriptions related to the following embodiments can be applied to each other as long as they are not technically contradictory. The following embodiments can also be combined with each other as long as they are not technically contradictory.

[0161] The resin layer 2 is, for example, located between the polarizer 1 and the adhesive layer 3, and is directly in contact with the polarizer 1 and the adhesive layer 3, respectively. Among them, other layers such as an adhesive layer and an easy-bonding layer may be arranged between the resin layer 2 and the polarizer 1. For example, the resin layer 2 may be bonded to the polarizer 1 via an adhesive layer or an easy-bonding layer. As the adhesive layer and the easy-bonding layer for bonding the resin layer 2 to the polarizer 1, those described above for the polarizing film 10 may be cited. In the case where the resin layer 2 is located closer to the image display panel side than the polarizer 1, it is possible to suppress the iodine contained in the polarizer 1 from moving to the adhesive layer 5 and passing through the adhesive layer 5 to the outside of the polarizing film 11 in a high temperature and humid environment.

[0162] (Another Modification of Polarizing Film)

[0163] The polarizing film 10 may further include other components in addition to the above-mentioned components. Figure 3 As shown, the polarizing film 12 of this modified example further has a transparent protective film (second transparent protective film) 6. The structure of the polarizing film 12 is the same as that of the polarizing film 10 except for the second transparent protective film 6. Therefore, the same reference numerals are used for the common elements in the polarizing film 10 and the polarizing film 12 of the modified example, and their description may be omitted.

[0164] The second transparent protective film 6 is located closer to the visible side than the polarizer 1. The polarizer 1 is located, for example, between the first transparent protective film 4 and the second transparent protective film 6. The second transparent protective film 6 is located, for example, closer to the visible side than the resin layer 2, and is located at the outermost side of the polarizing film 12. In the case where the polarizing film 12 has the above-mentioned transparent substrate, the second transparent protective film 6 can be located between the resin layer 2 and the transparent substrate. The second transparent protective film 6 is, for example, directly in contact with the resin layer 2. However, the second transparent protective film 6 can also be bonded to the resin layer 2 via other layers such as an adhesive layer and a hard coating layer. As the adhesive layer for bonding the second transparent protective film 6 to the resin layer 2, for example, those described above for the adhesive layer 3 can be cited.

[0165] As the second transparent protective film 6, those described above for the first transparent protective film 4 can be used. The first transparent protective film 4 and the second transparent protective film 6 may be the same or different.

[0166] In the polarizing film 12 having the second transparent protective film 6, there is a tendency to further suppress the transmission of iodine contained in the polarizer 1 to the outside in a high temperature and high humidity environment. As an example, when the polarizing film 12 is placed in an atmosphere of 65°C and 90% RH for 120 hours in a state where the polarizing film 12 is bonded to an alkali-free glass via the adhesive layer 5, the change ΔY2 of the single transmittance of the polarizing film 12 is, for example, 3 or less, preferably 2 or less, more preferably 1.5 or less, further preferably 1 or less, and particularly preferably 0.8 or less.

[0167] Specifically, the change in single transmittance ΔY2 can be measured by the following method. First, the polarizing film 12 is bonded to the alkali-free glass via the adhesive layer 5 to obtain a laminate, and the single transmittance Ts3 of the obtained laminate is measured. Next, the laminate is placed in an atmosphere of 65°C and 90% RH for 120 hours. The single transmittance Ts4 of the laminate after being placed in the atmosphere is measured. The value obtained by subtracting the single transmittance Ts3 from the single transmittance Ts4 is regarded as the change in single transmittance ΔY2.

[0168] The single transmittance Ts3 is not particularly limited, and is, for example, 42% to 46%, preferably 43% or more, and more preferably 44% or more. The single transmittance Ts4 is not particularly limited, and is, for example, 42% to 48%, preferably 47% or less, and more preferably 46% or less.

[0169] (Another Modification of Polarizing Film)

[0170] The polarizing film 10 may include two or more resin layers 2. Figure 4 As shown, the polarizing film 13 of this modification example includes two resin layers 2a and 2b. Except for the resin layer 2b, the structure of the polarizing film 13 is the same as that of the polarizing film 10. Therefore, the same reference numerals are used for the common elements in the polarizing film 10 and the polarizing film 13 of the modification example, and their description may be omitted.

[0171] In the polarizing film 13, the polarizer 1 is located between the two resin layers 2a and 2b. Specifically, the resin layer 2b is located closer to the image display panel side than the polarizer 1 (for example, between the polarizer 1 and the adhesive layer 3). When the polarizer 1 is arranged between the two resin layers 2a and 2b, in the polarizing film 13, there is a tendency to further suppress the transmission of iodine contained in the polarizer 1 to the outside.

[0172] The resin layer 2b can be directly in contact with the polarizer 1. However, other layers such as an adhesive layer and an easy-adhesion layer may be disposed between the resin layer 2b and the polarizer 1. For example, the resin layer 2b can be bonded to the polarizer 1 via an adhesive layer or an easy-adhesion layer. As the adhesive layer and the easy-adhesion layer for bonding the resin layer 2b to the polarizer 1, those described above for the polarizing film 10 can be cited.

[0173] (Embodiment of Image Display Device)

[0174] like Figure 5 As shown, the image display device 100 of the present embodiment includes a polarizing film 10 and an image display panel 20. In the image display device 100, a polarizing film 11, 12 or 13 may be used instead of the polarizing film 10. In the image display device 100, the polarizing film 10 is bonded to the image display panel 20 via, for example, an adhesive layer 5. As the image display panel 20, an organic EL display panel, a liquid crystal display panel, etc. may be cited, and an organic EL display panel is preferably used.

[0175] The image display device 100 further includes an illumination system (not shown). For example, the polarizing film 10 , the image display panel 20 , and the illumination system are arranged in this order, with the polarizing film 10 being located closest to the visible side. The illumination system includes, for example, a backlight or a reflector, and irradiates light to the image display panel 20 .

[0176] Example

[0177] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples shown below.

[0178] <Thin polarizer>

[0179] First, a laminate having a PVA layer with a thickness of 9 μm formed on an amorphous polyethylene terephthalate (PET) substrate was prepared. The stretched laminate was prepared by auxiliary stretching the laminate in a gas atmosphere at a stretching temperature of 130°C. Next, the stretched laminate was dyed with iodine to obtain a colored laminate. The colored laminate was further stretched in a boric acid aqueous solution at a stretching temperature of 65 degrees, thereby obtaining a laminate in which the amorphous PET substrate and the PVA layer were stretched integrally. In the laminate, the total stretching ratio was 5.94 times, and the thickness of the PVA layer was 5 μm. Through the above-mentioned two-step stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate underwent a high-order orientation. Furthermore, through dyeing, the adsorbed iodine underwent a high-order orientation in one direction in the form of a polyiodide ion complex. The PVA layer contained in the laminate functions as a thin polarizer.

[0180] <Transparent protective film>

[0181] First, a resin (imidized MS resin) composed of an imidized methyl methacrylate-styrene copolymer was prepared by the method described in Manufacturing Example 1 of Japanese Patent Publication No. 2010-284840. Next, 100 parts by weight of the imidized MS resin and 0.62 parts by weight of a triazine ultraviolet absorber (manufactured by ADEKA Co., Ltd., trade name: T-712) were mixed at 220°C using a twin-screw mixer to prepare resin particles. The obtained resin particles were dried in an environment of 100.5 kPa and 100°C for 12 hours. Next, a single-screw extruder was used to extrude the resin particles from a T die at a die temperature of 270°C, thereby preparing a film with a thickness of 160 μm. The film was further stretched in an atmosphere of 150°C along its conveying direction to adjust the thickness to 80 μm. Next, an adhesive agent containing an aqueous urethane resin was applied to the film, and the film was stretched in an atmosphere at 150° C. in a direction perpendicular to the conveying direction to obtain a transparent protective film having a thickness of 40 μm. The moisture permeability of the transparent protective film was 58 g / m 2 / 24h.

[0182] <Active energy ray-curable adhesive composition>

[0183] 12 parts by weight of hydroxyethyl acrylamide (manufactured by KJ Chemicals Inc., trade name: HEAA), 24 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toagosei Co., Ltd., trade name: ARONIX M-5700), 12 parts by weight of hydroxypivalic acid neopentyl glycol acrylic acid adduct (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE HPP-A), 38 parts by weight of 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE 1,9ND-A), 10 parts by weight of acrylic acid oligomer (manufactured by Toagosei Co., Ltd., trade name: ARUFON UP-1190), 3 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (manufactured by IGM Resins Co., Ltd., trade name: OMNIRAD 907) and 2 parts by weight of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S) were mixed and stirred for 3 hours to obtain an active energy ray-curable adhesive composition.

[0184] <Laminate comprising a transparent protective film, an adhesive layer, and a thin polarizer>

[0185] Using an MCD coater manufactured by Fuji Machine Co., Ltd. (unit shape: honeycomb, gravure roller line number: 1000 lines / inch, rotation speed 140% / pair of line speed), the active energy ray-curable adhesive composition was applied to the bonding surface of the transparent protective film, and the thickness of the obtained coating film was 0.7μm. Next, using a roller machine, the transparent protective film and the laminate containing the PVA layer were bonded. At this time, the coating film was brought into contact with the PVA layer. The line speed of the roller machine was 25m / min. Next, the obtained laminate was irradiated with active energy rays from the transparent protective film side. As active energy rays, visible light emitted by a visible light irradiation device (Light HAMMER10 manufactured by FusionUV Systems) was used. The light source of the visible light irradiation device is a metal halide lamp enclosed in gallium. In the visible light irradiation device, a V valve is used as a valve. The peak illuminance of the emitted light from the visible light irradiation device is 1600mW / cm 2 In the wavelength range of 380nm to 440nm, the cumulative irradiation amount of the emitted light from the visible light irradiation device is 1000mJ / cm 2 The illuminance of the emitted light from the visible light irradiation device was measured using the Sola-Check system manufactured by Solatell. The active energy ray-curable adhesive composition in the coating film was cured by irradiating the laminate with active energy rays. Next, the laminate was hot-air dried at 70°C for 3 minutes, thereby obtaining a laminate a comprising a transparent protective film, an adhesive layer and a thin polarizer.

[0186] [Example 1]

[0187] (Polarizing film A)

[0188] First, 50 parts by weight of dicyclopentanyl acrylate (manufactured by Hitachi Chemical Co., Ltd., trade name: FANCRYL FA-513AS), 50 parts by weight of pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHTACRYLATE PE-4A), 2 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (manufactured by IGM Resins Co., Ltd., trade name: OMNIRAD 907), and 2 parts by weight of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S) were mixed to prepare a coating liquid.

[0189] Next, the amorphous PET substrate adjacent to the PVA layer was removed from the laminate a. The coating solution was applied to the exposed PVA layer using Select-Roller #0 (manufactured by OGS SYSTEM PRODUCTS Co., Ltd.), and the thickness of the obtained coating film was 1 μm. Next, the coating film was irradiated with visible light under a nitrogen gas flow using the visible light irradiation device described above, thereby polymerizing the monomer. By polymerizing the monomer, the coating film was cured to form a resin layer.

[0190] Next, the surface of the transparent protective film was subjected to corona treatment. A 20 μm thick adhesive layer was bonded to the surface. The adhesive layer was composed of an acrylic adhesive. Thus, a polarizing film A having a resin layer, a polarizer, an adhesive layer, a transparent protective film, and an adhesive layer was obtained in this order.

[0191] (Polarizing film B)

[0192] First, a coating liquid was prepared by the same method as polarizing film A. Using an MCD coater manufactured by Fuji Machinery Co., Ltd. (unit shape: honeycomb, gravure roller line number: 700 lines / inch, rotation speed 140% / line speed), the coating liquid was applied to the bonding surface of a triacetyl cellulose (TAC) film with a thickness of 20 μm, and the thickness of the obtained coating film was 1 μm. Next, the amorphous PET substrate adjacent to the PVA layer was removed from the above-mentioned laminate a. The TAC film was bonded to the laminate a using a roller machine. At this time, the coating film was in contact with the PVA layer. The line speed of the roller machine was 25 m / min. Next, the obtained laminate was irradiated with active energy rays from the TAC film side. As the active energy ray, the visible light emitted by the above-mentioned visible light irradiation device was used. By irradiating the laminate with active energy rays, the monomers in the coating film were polymerized, and by polymerizing the monomers, the coating film was cured. Next, the laminate was hot-air dried at 70°C for 3 minutes, thereby forming a resin layer.

[0193] Next, the surface of the transparent protective film containing the imidized MS resin was subjected to a corona treatment. A 20 μm thick adhesive layer was bonded to the surface. The adhesive layer was composed of an acrylic adhesive. Thus, a polarizing film B having a TAC film (second transparent protective film), a resin layer, a polarizer, an adhesive layer, a transparent protective film containing the imidized MS resin (first transparent protective film), and an adhesive layer was obtained in sequence.

[0194] [Examples 2-16, Comparative Examples 1, 3 and 5]

[0195] Polarizing films A and B of Examples 2 to 16 and Comparative Examples 1, 3, and 5 were prepared in the same manner as in Example 1, except that the monomers contained in the coating liquid for forming the resin layer were changed to the monomers described in Table 1.

[0196] [Comparative Example 2]

[0197] Polarizing films A and B of Comparative Example 2 were produced by the same method as in Example 1 except that the photocurable resin composition A was used as a coating liquid for forming a resin layer. The photocurable resin composition A is a mixture of 43 parts by weight of acryloylmorpholine (manufactured by KJ Chemicals Inc., trade name: ACMO), 29 parts by weight of 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE 1,9ND-A), 14 parts by weight of phenoxydiethylene glycol acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE P2H-A), 10 parts by weight of acrylic oligomer (manufactured by Toagosei Co., Ltd., trade name: ARUFON UP-1190), 2 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907), and 2 parts by weight of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S).

[0198] [Comparative Example 4]

[0199] Polarizing films A and B of Comparative Example 4 were prepared by the same method as in Example 1 except that the photocurable resin composition B was used as the coating liquid for forming the resin layer. It should be noted that the photocurable resin composition B is 12 parts by weight of hydroxyethyl acrylamide (manufactured by KJ Chemicals Inc., trade name: HEAA), 20 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toagosei Co., Ltd., trade name: ARONIX M-5700), 12 parts by weight of hydroxypivalic acid neopentyl glycol acrylic acid adduct (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE HPP-A), 34 parts by weight of 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: LIGHT ACRYLATE 1,9ND-A), 10 parts by weight of acrylic oligomer (manufactured by Toagosei Co., Ltd., trade name: ARUFON UP-1190), 5 parts by weight of diethyl acrylamide (KJ Chemicals Inc., trade name: DEAA), 3 parts by weight of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907) and 3 parts by weight of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S).

[0200] <Change in single-unit transmittance ΔY1>

[0201] The change in monomer transmittance ΔY1 of the polarizing film A of the embodiment and the comparative example was measured by the following method. First, the polarizing film A was bonded to the alkali-free glass via an adhesive layer. The monomer transmittance Ts1 of the obtained laminate was measured. The monomer transmittance Ts1 was measured using a spectral transmittance meter with an integrating sphere (Dot-3c manufactured by Murakami Color Technology Laboratory). Next, the laminate was placed in an atmosphere of 65°C and 90% RH for 24 hours. Using the above-mentioned spectral transmittance meter, the monomer transmittance Ts2 of the laminate placed in the atmosphere was measured. The change in monomer transmittance ΔY1 is calculated by subtracting the monomer transmittance Ts1 from the monomer transmittance Ts2.

[0202] <Change in single-unit transmittance ΔY2>

[0203] The change in monomer transmittance ΔY2 of the polarizing film B of the embodiment and the comparative example was measured by the following method. First, the polarizing film B was bonded to the alkali-free glass via an adhesive layer. The monomer transmittance Ts3 of the obtained laminate was measured. The monomer transmittance Ts3 was measured using a spectral transmittance meter with an integrating sphere (Dot-3c manufactured by Murakami Color Technology Laboratory). Next, the laminate was placed in an atmosphere of 65°C and 90% RH for 120 hours. Using the above-mentioned spectral transmittance meter, the monomer transmittance Ts4 of the laminate placed in the atmosphere was measured. The change in monomer transmittance ΔY2 was calculated by subtracting the monomer transmittance Ts3 from the monomer transmittance Ts4.

[0204] <y calculated by formula (1) 1 Value>

[0205] The monomers contained in the coating liquids for forming the resin layers used in the examples and comparative examples were identified by the above-mentioned method. 1 ~x 3 The value of . It should be noted that the number of rotatable bonds and the number of reaction points contained in the monomer were calculated using Dragon (version 7.0). The polar term δP (MPa) in the Hansen solubility parameter of the monomer 1 / 2 ) is calculated using HSPiP (version 5). 1 ~x 3 The value of y is calculated based on formula (1) 1 The value of .

[0206] <y calculated by formula (2) 2 Value>

[0207] The monomers contained in the coating liquids for forming the resin layers used in the examples and comparative examples were identified by the above-mentioned method. 1 ~x 5 The value of . It should be noted that the number of rotatable bonds and the number of reaction points contained in the monomer were calculated using Dragon (version 7.0). The polar term δP (MPa) in the Hansen solubility parameter of the monomer 1 / 2 ) was calculated using HSPiP (version 5). The charge of each atom constituting the monomer and the x component in the dipole moment were calculated using Materials Studio (BIOVIA, ver. 8.0.0.843) and WebMO (ver. 19.0.009e). 1 ~x 5 The value of y is calculated based on formula (2) 2 The value of .

[0208] <Tensile modulus E1 and E2>

[0209] The tensile moduli E1 and E2 of the resin layers used in Examples and Comparative Examples were measured by the above-mentioned method. As a dynamic viscoelasticity measuring apparatus, a dynamic viscoelasticity measuring apparatus RSA-G2 manufactured by TA Instruments was used.

[0210] <Linear expansion coefficient α1 and α2>

[0211] The linear expansion coefficients α1 and α2 of the resin layers used in the examples and comparative examples were measured by the above-mentioned method. As a thermomechanical analyzer, a thermomechanical analyzer TMA 4000 SE manufactured by Netch was used.

[0212] <Dipole moment D>

[0213] The dipole moment D of the monomers contained in the coating liquid for forming the resin layer used in Examples and Comparative Examples was calculated by the above method. The dipole moment D was calculated using Materials Studio (manufactured by BIOVIA, ver. 8.0.0.843) and WebMO (ver. 19.0.009e).

[0214]

[0215] It should be noted that the abbreviations in Table 1 are as follows.

[0216] FA513AS: Dicyclopentanyl acrylate, manufactured by Hitachi Chemical Co., Ltd.

[0217] TMP-A: Trimethylolpropane triacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0218] TBCHA: 4-tert-butylcyclohexyl acrylate, manufactured by KJ Chemicals Inc.

[0219] DCP-A: dimethyloltricyclodecane diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0220] GBLA: γ-butyrolactone acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0221] ACMO: Acryloylmorpholine, manufactured by KJ Chemicals Inc.

[0222] PE-4A: Pentaerythritol tetraacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0223] DPE-6A: Dipentaerythritol hexaacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0224] 1,9ND-A: 1,9-nonanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0225] 9EG-A: Polyethylene glycol #400 diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0226] According to Table 1, we can see that in the y calculated by formula (1) 1 The value of , or the value of y calculated by formula (2) 2 In the polarizing film A of the embodiment in which the value of is less than 1.3, the change ΔY1 of the single transmittance is less than 5, which fully suppresses the iodine from being transmitted to the outside in a high temperature and high humidity environment. Similarly, in the polarizing film B of the embodiment, the change ΔY2 of the single transmittance is less than 3, which fully suppresses the iodine from being transmitted to the outside in a high temperature and high humidity environment. On the other hand, in the case of 1 The value of y 2 In the polarizing films A and B of the comparative examples in which the value of was 1.3 or more, the change in the single transmittance was large compared with the example, and the permeation of iodine to the outside in a high-temperature and high-humidity environment could not be sufficiently suppressed.

[0227] Furthermore, the monomers contained in the active energy ray-curable resin compositions used in Examples 1 to 4 and Comparative Example 1 of Patent Document 1 were identified by the above-mentioned method. 1 ~x 5 ,y 1 and 2 These active energy ray-curable resin compositions contain only epoxy compounds as monomers and do not contain (meth)acrylates. 1 and 2 The value of y can fully predict the properties of the cured layer of the active energy ray-curable resin composition. 1And y calculated by formula (2) 2 In particular, it is suitable as an index for predicting the characteristics of a resin layer containing a polymer having a structural unit of a polyfunctional (meth)acrylate.

[0228] Industrial Applicability

[0229] The polarizing film of the present invention can be suitably used for mobile displays such as mobile phones, smartphones, and notebook computers; and in-vehicle displays such as instrument panels for car navigation devices, instrument clusters, and mirror displays.

Claims

1. A polarizing film, comprising: A polarizer containing iodine, and a resin layer comprising a polymer having a structural unit derived from a monofunctional (meth)acrylate and a structural unit derived from a polyfunctional (meth)acrylate, in, The dipole moment D of the monomer used to form the polymer is 2 Debye or less, y calculated by the following formula (1) 1 The value of is less than 1.3, y 1 =(0.279)x 1 +(-1.51)x 2 +(0.178)x 3 +0.386 (1) In the formula (1), x 1 is the number of rotatable bonds contained in the monomer used to form the polymer, x 2 is the number of reactive sites contained in the monomer used to form the polymer, x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the monomer used to form the polymer 1 / 2 ).

2. The polarizing film according to claim 1, in, The 1 The value is less than 0.

5.

3. The polarizing film according to claim 1, in, At least one of the following requirements (i) to (iv) is met, (i) The tensile modulus E1 of the resin layer in 65°C water is 1×10 8 Pa or above; (ii) The tensile modulus E2 of the resin layer in 85°C water is 1×10 8 Pa or above; (iii) When the resin layer is heated from 25°C to 65°C and the measurement atmosphere is humidified from 10%RH to 90%RH, the linear expansion coefficient α1 of the resin layer is 400×10 -6 / K or less; (iv) When the resin layer is heated from 25°C to 85°C and the measurement atmosphere is humidified from 10%RH to 85%RH, the linear expansion coefficient α2 of the resin layer is 300×10 -6 / K or less.

4. The polarizing film according to claim 1, in, In the polymer, the total content of the structural unit derived from the monofunctional (meth)acrylate and the structural unit derived from the polyfunctional (meth)acrylate is higher than 70% by weight.

5. The polarizing film according to claim 1, in, The content of the structural unit derived from the polyfunctional monomer in the polymer is 20% by weight or more.

6. The polarizing film according to claim 1, in, The content of the structural unit derived from the monomer having a polar group in the polymer is 20% by weight or less.

7. The polarizing film according to claim 1, in, The resin layer is located closer to the viewing side than the polarizer.

8. The polarizing film according to claim 1, in, The resin layer is directly in contact with the polarizer.

9. The polarizing film according to claim 1, comprising two resin layers. The polarizer is located between the two resin layers.

10. The polarizing film according to claim 1, further comprising an adhesive layer and a first transparent protective film, The polarizer, the adhesive layer, and the first transparent protective film are arranged in this order in a lamination direction.

11. The polarizing film according to claim 10, further comprising a second transparent protective film, The polarizer is located between the first transparent protective film and the second transparent protective film. 12 . The polarizing film according to claim 1 , further comprising a pressure-sensitive adhesive layer. The polarizer is located closer to the viewing side than the adhesive layer.

13. An image display device comprising: The polarizing film according to any one of claims 1 to 12, and Image display panel.

14. A method for manufacturing a polarizing film, the polarizing film comprising: A polarizer containing iodine, and a resin layer comprising a polymer having a structural unit derived from a monofunctional (meth)acrylate and a structural unit derived from a polyfunctional (meth)acrylate, The manufacturing method include: Let y calculated by the following formula (1) 1 A step of polymerizing a monomer having a value of less than 1.3 to obtain the polymer, The dipole moment D of the monomer is less than 2 Debye, y 1 =(0.279)x 1 +(-1.51)x 2 +(0.178)x 3 +0.386 (1) In the formula (1), x 1 is the number of rotatable bonds contained in the monomer, x 2 is the number of reaction sites contained in the monomer, x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the monomer 1 / 2 ).

15. The manufacturing method according to claim 14, further comprising: include: forming a film containing the monomer and the polymerization initiator on the polarizer, The monomer is polymerized so that the resin layer is formed from the film.

16. The manufacturing method according to claim 15, in, The polymerization initiator is a photopolymerization initiator, The monomer is polymerized by irradiating the film with active energy rays.

17. A polarizing film comprising: A polarizer containing iodine, and a resin layer comprising a polymer having a structural unit derived from a monofunctional (meth)acrylate and a structural unit derived from a polyfunctional (meth)acrylate, in, The dipole moment D of the monomer used to form the polymer is 2 Debye or less, y calculated by the following formula (2) 2 The value of is less than 1.3, y 2 =(0.255)x 1 +(-1.57)x 2 +(0.151)x 3 +(-18.0)x 4 +(0.0987)x 5 +(-8.26) (2) In the formula (2), x 1 is the number of rotatable bonds contained in the monomer used to form the polymer, x 2 is the number of reactive sites contained in the monomer used to form the polymer, x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the monomer used to form the polymer 1 / 2 ), x 4 is the charge (C) of the most negatively charged atom among the atoms functioning as hydrogen bond acceptors in the monomer used to form the polymer, x 5 is the x component (Debye) in the dipole moment of the monomer used to form the polymer.

18. A method for manufacturing a polarizing film, the polarizing film comprising: A polarizer containing iodine, and a resin layer comprising a polymer having a structural unit derived from a monofunctional (meth)acrylate and a structural unit derived from a polyfunctional (meth)acrylate, The manufacturing method include: Let y calculated by the following formula (2) 2 A step of polymerizing a monomer having a value of less than 1.3 to obtain the polymer, The dipole moment D of the monomer is less than 2 Debye, y 2 =(0.255)x 1 +(-1.57)x 2 +(0.151)x 3 +(-18.0)x 4 +(0.0987)x 5 +(-8.26) (2) In the formula (2), x 1 is the number of rotatable bonds contained in the monomer used to form the polymer, x 2 is the number of reactive sites contained in the monomer used to form the polymer, x 3 is the polar term δP (MPa) in the Hansen solubility parameter of the monomer used to form the polymer 1 / 2 ), x 4 is the charge (C) of the most negatively charged atom among the atoms functioning as hydrogen bond acceptors in the monomer used to form the polymer, x 5 is the x component (Debye) in the dipole moment of the monomer used to form the polymer.

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