WO2021192568A1

WO2021192568A1 - Polarizing film and image display device

Info

Publication number: WO2021192568A1
Application number: PCT/JP2021/002317
Authority: WO
Inventors: 菅野　亮; 基輔片山; 芳人福山
Original assignee: 日東電工株式会社
Priority date: 2020-03-27
Filing date: 2021-01-22
Publication date: 2021-09-30
Also published as: TW202136057A; KR20220150278A; CN115298587A; JP7382264B2; JP2021157063A

Abstract

The present invention provides a polarizing film in which the permeation of iodine contained in a polarizer to the outside under a high-temperature high-humidity environment can be inhibited satisfactorily. The polarizing film according to the present invention is provided with a polarizer and a resin layer comprising a polymer, and satisfies at least one of the following requirements (i) to (v). (i) The tensile storage modulus E1 of the resin layer is 1 × 108 Pa or more. (ii) The tensile storage modulus E2 of the resin layer is 1 × 108 Pa or more. (iii) The linear expansion coefficient α1 of the resin layer is 400 × 10-6/K or less. (iv) The linear expansion coefficient α2 of the resin layer is 300 × 10-6/K or less. (v) The dipole moment D of a monomer used for the formation of the polymer is 2 Debye or less.

Description

Polarizing film and image display device

The present invention relates to a polarizing film and an image display device.

Image display devices such as liquid crystal display devices and organic EL display devices are provided with a polarizing film for reasons such as the display principle thereof. The polarizing film is, for example, a laminate containing a polarizer and a transparent protective film. The polarizer can generally be produced by adsorbing a dichroic dye on a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film and uniaxially stretching the film. Iodine is widely used as the dichroic dye from the viewpoint of improving the transmittance and the degree of polarization of the polarizer.

Patent Document 1 discloses an optical laminate in which a polarizer and a protective film are adhered to each other via a cured layer of a curable resin composition. From Patent Document 1, by appropriately adjusting the content of the alicyclic epoxy compound in the curable resin composition, iodine in the cured layer is obtained even when the optical laminate is placed in a high temperature and high humidity environment. It can be read that the content rate of the resin can be kept low.

JP-A-2018-169512

In a hot and humid environment, iodine contained in the polarizing element tends to move from the polarizer to a transparent protective film or an adhesive layer for attaching 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 easily moves from the polarizer to the transparent protective film or the pressure-sensitive adhesive layer. Iodine transferred to the transparent protective film or the pressure-sensitive adhesive layer permeates the outside of the polarizing film through the transparent protective film or the pressure-sensitive adhesive layer. When the iodine content in the polarizer decreases, the degree of polarization of the polarizing film decreases.

With the conventional polarizing film, it is not possible to sufficiently suppress the permeation of iodine contained in the polarizer to the outside of the polarizing film in a high temperature and high humidity environment. For example, Patent Document 1 pays attention to keeping the iodine content in the cured layer low when the optical laminate is placed in a high temperature and high humidity environment. However, Patent Document 1 does not consider that iodine is transmitted from the polarizer to the outside of the optical laminate.

Therefore, an object of the present invention is to provide 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.

As a result of diligent studies, the present inventors have obtained the tensile storage elastic modulus of the resin layer, the linear expansion modulus of the resin layer, and the monomer for forming the polymer contained in the resin layer in the polarizing film provided with the resin layer. We have newly found that each of the dipole moments can be used as an index for the permeation of iodine to the outside, and have completed the present invention.

The present invention
With a polarizer containing iodine,
With a resin layer containing a polymer,
Provided is a polarizing film that satisfies at least one of the following requirements (i) to (v).
(I) a tensile storage modulus E1 of the resin layer at 65 ° C. in water is 1 × 10 ⁸ Pa or more.
(Ii) tensile storage modulus E2 of the resin layer at 85 ° C. in water is 1 × 10 ⁸ Pa or more.
(Iii) When the resin layer is heated from 25 ° C. to 65 ° C. and the measurement atmosphere is further humidified from 10% RH to 90% RH, the linear expansion coefficient α1 of the resin layer is 400 × 10 ^-6 / K or less. be.
(Iv) When the resin layer is heated from 25 ° C. to 85 ° C. and the measurement atmosphere is further humidified from 10% RH to 85% RH, the linear expansion coefficient α2 of the resin layer is 300 × 10 ^-6 / K or less. be.
(V) The dipole moment D of the monomer for forming the polymer is 2 Debye or less.

According to the present invention, it is possible to provide 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.

It is a schematic cross-sectional view of the polarizing film which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the modification of the polarizing film. It is the schematic sectional drawing which shows another modification of the polarizing film. It is the schematic cross-sectional view which shows the further modification of the polarizing film. It is a schematic cross-sectional view of the image display device which concerns on one Embodiment of this invention.

Hereinafter, the details of the present invention will be described, but the following description is not intended to limit the present invention to a specific embodiment.

(Implementation of polarizing film)
As shown in FIG. 1, the polarizing film 10 of the present embodiment includes a polarizing element 1 containing iodine and a resin layer 2 containing a polymer P. The resin layer 2 is located on the visual side of the polarizer 1 and is in direct contact with the polarizer 1, for example. However, other layers such as an adhesive layer and an easy-adhesion layer may be arranged between the resin layer 2 and the polarizer 1 as long as the effects of the present invention are not impaired. The resin layer 2 may be located closer to the image display panel, which will be described later, than the polarizer 1. In other words, the polarizer 1 may be located on the visual side of the resin layer 2. The resin layer 2 is located, for example, on the outermost side of the polarizing film 10. In addition, in this specification, a "film" means a member whose thickness is sufficiently smaller than the length and width.

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 is attached to the polarizer 1 via, for example, the adhesive layer 3. The pressure-sensitive adhesive layer 5 functions as, for example, a member for adhering the polarizing film 10 to an image display panel described later. Therefore, the pressure-sensitive adhesive layer 5 is located on the outermost side of the polarizing film 10, for example, on the image display panel side of the polarizing element 1. In other words, the polarizer 1 is located on the visual side of the pressure-sensitive adhesive layer 5, for example. The resin layer 2, the polarizer 1, the adhesive layer 3, the transparent protective film 4, and the pressure-sensitive adhesive layer 5 are arranged in this order, for example, in the stacking direction.

In the polarizing film 10 of the present embodiment, at least one of the following requirements (i) to (v) is satisfied, and preferably requirement (iii) is satisfied. In the polarizing film 10, all of the requirements (i) to (v) may be satisfied.
(I) a tensile storage modulus E1 of the resin layer 2 at 65 ° C. in water is 1 × 10 ⁸ Pa or more.
(Ii) The tensile storage elastic modulus E2 of the resin layer 2 at 85 ° C. in water is 1 × 10 ⁸ Pa or more.
(Iii) When the resin layer 2 is heated from 25 ° C. to 65 ° C. and the measurement atmosphere is further humidified from 10% RH to 90% RH, the linear expansion coefficient α1 of the resin layer 2 is 400 × 10 ^-6 / K or less. be.
(Iv) When the resin layer 2 is heated from 25 ° C. to 85 ° C. and the measurement atmosphere is further humidified from 10% RH to 85% RH, the linear expansion coefficient α2 of the resin layer 2 is 300 × 10 ^-6 / K or less. be.
(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.

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

The tensile storage elastic modulus E1 of the resin layer 2 can be measured by, for example, the following method. First, the resin layer 2 to be evaluated is cut into strips having a width of 5 mm and a length of 30 mm to obtain test pieces. Next, the test piece is set in a commercially available dynamic viscoelasticity measuring device. At this time, a jig capable of immersing the test piece in a solvent is used. The distance between the clamps that secure 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 measurement of dynamic viscoelasticity of the test piece is started. The measurement is performed by the tensile vibration-non-resonant method specified in Japanese Industrial Standards (JIS) K7244-4: 1999. The vibration frequency 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 storage elastic modulus when the temperature of the test piece is 65 ° C. can be regarded as the tensile storage elastic modulus E1 of the resin layer 2.

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

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

The coefficient of linear expansion α1 of the resin layer 2 can be measured by, for example, the following method. First, the resin layer 2 to be evaluated is cut into strips having a width of 5 mm and a length of 30 mm to obtain test pieces. Next, the test piece is set in a commercially available thermomechanical analyzer. At this time, the distance between the clamps for fixing the test piece is set to 15 mm. The test piece is allowed to stand in a measurement atmosphere at 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 held for 10 minutes. Next, the measurement atmosphere is humidified from 10% RH to 90% RH over 30 minutes, and the test piece is held for 10 minutes. The coefficient of linear expansion α calculated from the following formula (1) can be regarded as the coefficient of linear expansion α1 of the resin layer 2 based on the amount of change ΔL (mm) in the length of the test piece before and after the test. In the formula (1), L ₀ means the length of the test piece at 25 ° C., and ΔT means the amount of change in the temperature of the test piece before and after the test. In requirement (iii), ΔT is 40 ° C.
Linear expansion coefficient α = ΔL / (L ₀ × ΔT) (1)

Next, requirement (iv) will be described. The coefficient of linear expansion α2 of the resin layer 2 is preferably 200 × 10 ^-6 / K or less, more preferably 170 × 10 ^-6 / K or less, and further preferably 150 × 10 ^-6 / K or less. , Particularly preferably 100 × 10 ^-6 / K or less. The lower limit of the linear expansion coefficient α2 is not particularly limited, but may be ^{, for example, 10 × 10 -6 / K from the viewpoint of suppressing cracks in the resin layer 2.} The coefficient of linear expansion α2 of the resin layer 2 is set except that, for example, the test piece is heated to 85 ° C. over 60 minutes and the measurement atmosphere is humidified from 10% RH to 85% RH over 30 minutes. It can be measured by the same method as the above-mentioned coefficient of linear expansion α1. In requirement (iv), ΔT of the above formula (1) is 60 ° C.

Next, the requirement (v) will be explained. The dipole moment D of the monomer M for forming the polymer P is preferably 1.7 Debye or less, more preferably 1.5 Debye or less, and further 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.

The dipole moment D can be calculated by, for example, the following method. First, the monomer M for forming the polymer P is specified. The dipole moment D can be calculated by performing a molecular simulation on the monomer M. The molecular simulation can be performed using known software such as Materials Studio (manufactured by BIOVIA, ver.8.0.0.843) and WebMO (ver.19.0.009e).

The calculation of the dipole moment D by the molecular simulation can be performed by, for example, the following method. First, a molecular model of monomer M is created using Materials Studio. For the molecular model, the force field of COMPASS (Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies) II is adopted to optimize the structure. Next, the molecular model of the monomer M is processed by WebMO. Specifically, in WebMO, a Gaussian program (Queue: g09) is used to perform structural optimization calculations for the molecular model of monomer M. At this time, B3LYP may be used as a functional, or 6-31G (d) may be used as a basis function. Thereby, the dipole moment D of the monomer M can be calculated.

When the polymer P is formed of a plurality of types of monomers M, the dipole moment D can be specified by the following method. First, the dipole moment is calculated for each of the plurality of types of monomers M by the above-mentioned method. The calculated dipole moment is weighted by the molar ratio of each monomer M to perform a weighted average. The obtained weighted average value can be regarded as the dipole moment D. Even when a plurality of types of monomers M are structural isomers of each other, the dipole moment D can be calculated by weighting the calculated dipole moments according to the molar ratio of each structural isomer and performing a weighted average. can.

When at least one of the requirements (i) and (ii) is satisfied, the polymer P contained in the resin layer 2 tends to be maintained in a state of low molecular mobility even in a high temperature and high humidity environment. When the molecular mobility of the polymer P is low, it is difficult to create a space in the resin layer 2 where iodine can enter. As a result, the movement of iodine from the polarizer 1 to the resin layer 2 can be suppressed, and the permeation of iodine to the outside of the polarizing film 10 can be suppressed.

When at least one of the requirements (iii) and (iv) is satisfied, the polymer P contained in the resin layer 2 tends to be maintained in a state where the free volume is small even in a high temperature and high humidity environment. When the free volume of the polymer P is small, it is difficult to create a space in the resin layer 2 where iodine can enter. As a result, the movement of iodine from the polarizer 1 to the resin layer 2 can be suppressed, and the permeation of iodine to the outside of the polarizing film 10 can be suppressed.

When requirement (v) is satisfied, electrostatic interaction tends to be less likely to occur between 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 can be suppressed, and the permeation of iodine to the outside of the polarizing film 10 can be suppressed.

In the polarizing film 10 of the present embodiment, the value of y calculated by the following formula (2) may be less than 1.3.
y = (0.279) x ₁ + ( _{-1.51) x 2} + (0.178) x ₃ + 0.386 (2)

In formula (2), x ₁ is the number of rotatable bonds contained in the monomer M for forming the polymer P. x ₁ can be an index for predicting how much the molecular motion of the polymer P is constrained. As used herein, the term "rotatable bond" refers to a single bond that connects heavy atoms, a bond that is included in the ring structure, and a single bond that connects a heavy atom located at the end to another heavy atom. It means the one excluding. The heavy atom means an atom other than a hydrogen atom and a helium atom, and specific examples thereof include a hetero atom such as a nitrogen atom and an oxygen atom, and a carbon atom. Specific examples of single bonds connecting heavy atoms are carbon-carbon bonds and carbon-heteroatom bonds. As an example, if the polymer P is formed from dimethylol-tricyclodecandiacrylate, the value of _{x 1 is 8.} The number of rotatable bonds may be calculated using software for calculating the molecular descriptor. Examples of such software include Dragon (version 7.0), alvaDesc, and the like.

When the polymer P is formed from a plurality of types of monomers M, the value of _{x 1 can be specified by the following method.} First, the number of rotatable bonds is calculated for each of the plurality of types of monomers M. The calculated number of rotatable bonds is weighted by the molar ratio of each monomer M to perform a weighted average. The weighted average value obtained can be regarded _{as x 1.} In the present embodiment, _{the value of x 1} is not particularly limited, and is, for example, 2 to 20.

x ₂ is the number of reaction points contained in the monomer M for forming the polymer P. x ₂ can be an index for predicting how many gaps are present in the polymer P so that the small molecule compound can pass through. As used herein, the term "reaction site" means a polymerizable group or a crosslinkable group. Specific examples of these groups include groups having a polymerizable double bond such as a (meth) acryloyl group, and crosslinkable functional groups such as an epoxy group and an oxetane group. As an example, if the polymer P is formed from dimethylol-tricyclodecanediacrylate, the value of _{x 2 is 2.} The number of reaction points may be calculated using software for calculating the molecular descriptor described above.

When the polymer P is formed from a plurality of types of monomers M, the value of _{x 2 can be specified by the following method.} First, the number of reaction points is calculated for each of the plurality of types of monomers M. The calculated number of reaction points is weighted by the molar ratio of each monomer M to perform a weighted average. The weighted average value obtained can be regarded _{as x 2.} In the present embodiment, _{the value of x 2} is not particularly limited, and is, for example, 1 to 6.

x ₃ ^{is the polarization term δP (MPa 1/2} ) in the Hansen solubility parameter of the monomer M for forming the polymer P. x ₃ can be an index for predicting the interaction that occurs between the polymer P and the water molecule or iodine. The Hansen solubility parameter is a solubility parameter introduced by Hildebrand divided into three components, a dispersion term δD, a polarization term δP, and a hydrogen bond term δH. The polarization term δP indicates the energy due to the dipole interaction between molecules. Details of the Hansen solubility parameter are disclosed in "Hansen Solubility Parameters; A Users Handbook (CRC Press, 2007)". The polarization term δP can be calculated using, for example, known software such as HSPiP (version5). The value of the polarization term δP may differ slightly depending on the software used. However, this error is usually negligible in calculating the value of y.

When the polymer P is formed from a plurality of types of monomers M, the value of _{x 3 can be specified by the following method.} ^{First, the polarization term δP (MPa 1/2} ) in the Hansen solubility parameter is calculated for each of the plurality of types of monomers M. The calculated polarization term δP is weighted by the molar ratio of each monomer M to perform a weighted average. The resulting weighted average can be regarded as x _3. In the present embodiment, _{the value of x 3} is not particularly limited, and is, for example, 1 to 10 (MPa ^1/2 ). The value of x ₃ is preferably 6 (MPa ^1/2 ) or less, more preferably 5 (MPa ^1/2 ) or less, and further preferably 4 (MPa ^1/2 ) or less.

The value of y calculated by the formula (2) is preferably 0.8 or less, more preferably 0.7 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. be.

The value of y calculated by the formula (2) is an index relating to the monomer M for forming the polymer P contained in the resin layer 2. However, according to the study by the present inventors, the value of y is also useful as an index for selecting the resin layer 2 suitable for suppressing the permeation of iodine contained in the polarizer 1 to the outside. The value of y is particularly suitable as an index for predicting the characteristics of the resin layer containing the polymer having the structural unit derived from the (meth) acrylic acid ester.

[Polarizer]
The polarizer 1 is not particularly limited as long as it contains iodine, and is used in hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene-vinyl acetate copolymer-based partially saponified films. Examples thereof include those in which iodine is adsorbed and uniaxially stretched. The polarizer 1 is preferably composed of a polyvinyl alcohol-based film and iodine.

The thickness of the polarizer 1 is not particularly limited, and is, for example, 30 μm or less, preferably 20 μm or less, more preferably 18 μm or less, still more preferably 15 μm or less, and particularly preferably 12 μm or less. Particularly preferably, it is 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 in some cases, 1 to 7 μm, particularly 4 to 6 μm. In the present specification, the polarizer 1 having a thickness of 10 μm or less may be referred to as a thin polarizer. The thin polarizing element tends to have less uneven thickness and excellent visibility. Further, the thin polarizer has an advantage that the dimensional change is suppressed and the durability is excellent. According to the thin polarizing element, the polarizing film 10 can be made thinner. When the polarizing element 1 is a thin polarizing element, it is necessary to adjust the concentration of iodine in the polarizing element 1 to be high in order for the polarizing film 10 to have a practically sufficient degree of polarization. In the polarizing film 10 of the present embodiment, even when the thickness of the polarizing element 1 is small and the concentration of iodine in the polarizing element 1 is high, the permeation of iodine from the polarizing element 1 to the outside is sufficiently suppressed. Can be done.

The polarizer 1 can be produced by dyeing a hydrophilic polymer film such as a polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. The hydrophilic polymer film may be immersed in an aqueous solution containing boric acid, potassium iodide and the like, if necessary. Further, if necessary, the hydrophilic polymer film may be immersed in water and washed with water before dyeing. By washing the hydrophilic polymer film with water, stains and blocking inhibitors adhering to the surface can be washed. When the hydrophilic polymer film is washed with water, the hydrophilic polymer film swells, which also has the effect of suppressing uneven dyeing. The hydrophilic polymer film may be stretched after dyeing with iodine, while dyeing, or before dyeing with iodine. The hydrophilic polymer film may be stretched in an aqueous solution containing boric acid, potassium iodide, or the like, or in water.

Typical examples of the thin polarizing element include JP-A-51-069644, JP-A-2000-338329, International Publication No. 2010/100917, JP-A-2014-59328, and JP-A-2012-73563. The ones described in the above can be mentioned. These thin polarizers are produced by a manufacturing method including a step of stretching a laminate containing a polyvinyl alcohol-based resin (PVA-based resin) layer and a resin base material for stretching, and a step of dyeing the obtained stretched film. can. In this manufacturing method, since the PVA-based resin layer is supported by the resin base material for stretching, defects such as breakage due to stretching are unlikely to occur.

From the viewpoint of being able to stretch at a high magnification and improving the polarization performance, the thin polarizer is preferably manufactured by a manufacturing method including a stretching step in a boric acid aqueous solution among the above manufacturing methods. In particular, it is preferably produced by a production method including a step of performing auxiliary aerial stretching before the stretching step in an aqueous boric acid solution. A production method including a stretching step in an aqueous boric acid solution is disclosed in International Publication No. 2010/100917, JP-A-2014-59328, JP-A-2012-73563 and the like. A production method including a step of carrying out air stretching is disclosed in JP-A-2014-59328, JP-A-2012-73563 and the like.

[Resin layer]
The polymer P contained in the resin layer 2 and the resin layer 2 is not particularly limited as long as at least one of the above-mentioned requirements (i) to (v) is satisfied. The polymer P contains, for example, a structural unit derived from one monomer selected from the group consisting of a radically polymerizable monomer, a cationically polymerizable monomer and an anionically polymerizable monomer, and preferably contains a structural unit derived from a radically polymerizable monomer. include. The polymer P may contain a structural unit derived from a radically polymerizable monomer and a structural unit derived from a cationically polymerizable monomer.

Examples of the radically polymerizable monomer include (meth) acrylic acid ester and a styrene compound. As used herein, "(meth) acrylic acid" means acrylic acid and / or methacrylic acid.

The (meth) acrylic acid ester may be a monofunctional (meth) acrylic acid ester having one (meth) acryloyl group, or a polyfunctional (meth) acrylic acid ester having two or more (meth) acryloyl groups. May be. The polymer P preferably contains a structural unit derived from a polyfunctional (meth) acrylic acid ester. According to the polymer P containing a structural unit derived from a polyfunctional (meth) acrylic acid ester, the transfer of iodine from the polarizer 1 to the resin layer 2 tends to be more suppressed. The number of (meth) acryloyl groups contained in the polyfunctional (meth) acrylic acid ester is not particularly limited, and is, for example, 2 to 6, preferably 2 to 4. If the number of (meth) acryloyl groups contained in the polyfunctional (meth) acrylic acid ester is too large, unreacted (meth) acryloyl groups may remain in the polymer P.

The carbon number of the portion other than the (meth) acryloyl group in the (meth) acrylic acid ester (hereinafter, may be referred to as an ester moiety) is not particularly limited, and is, for example, 1 to 18, preferably 4 to 10. .. The ester moiety may include a ring structure. The ring structure may contain heteroatoms such as nitrogen atoms and oxygen atoms, but is preferably composed only of alicyclic hydrocarbons. The ring structure may be a condensed ring structure such as tricyclodecane or a monocyclic structure such as cyclohexane. The ester moiety may contain a functional group such as an ether group.

The (meth) acrylic acid ester may contain a polar group, but preferably does not contain a polar group. As used herein, a polar group means a group containing a bond between a hydrogen atom and a hetero atom such as an oxygen atom or a nitrogen atom. Examples of the polar group include a hydroxyl group, a carboxyl group, a primary amine group and a secondary amine group.

Examples of the (meth) acrylic acid ester include dicyclopentanyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, lauryl (meth) acrylate, and 5- (meth) acrylicoxy-2,6-norbornan. Carbolactone, 3,3,5-trimethylcyclohexyl (meth) acrylate, 4-t-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-anthracene (meth) acrylate, 1-anthracene methyl (meth) acrylate, 9-anthracene methyl (meth) acrylate and other monofunctional (meth) acrylic acid esters; dimethylol-tricyclode Candi (meth) acrylate, 1,3-adamantandiol di (meth) acrylate, 1,3,5-adamantantriol-1,5-di (meth) acrylate, 9,9-bis [4- (2- (meth) acrylate) ) Acryloyloxyethoxy) phenyl] Bifunctional (meth) acrylic acid esters such as fluorene; trimethylpropantri (meth) acrylates, glycerintri (meth) acrylates, 1,3,5-adamantantrioltri (meth) acrylates, etc. Examples thereof include trifunctional (meth) acrylic acid ester; tetrafunctional (meth) acrylic acid ester such as pentaerythritol tetra (meth) acrylate; and hexafunctional (meth) acrylic acid ester such as dipentaerythritol hexa (meth) acrylate.

The styrene compound contains, for example, an aromatic ring and one or more vinyl groups. Like the (meth) acrylic acid ester, the styrene-based compound may contain a polar group, but preferably does not contain a polar group. Examples of the styrene compound include styrene, α-methylstyrene, vinylbenzyl chloride, butoxystyrene, vinylpyridine and the like.

The polymer P preferably contains a structural unit derived from a radically polymerizable monomer as a main component, and preferably is substantially composed of a structural unit derived from a radically polymerizable monomer. In the present specification, the "main component" means the structural unit contained most in the polymer P on a weight basis. In particular, the polymer P preferably contains a structural unit derived from the (meth) acrylic acid ester, and the content thereof is, for example, 50% by weight or more, preferably higher than 70% by weight, and more preferably 80% by weight. % Or more, more preferably 90% by weight or more, particularly preferably 95% by weight or more, and particularly preferably 99% by weight or more.

Examples of the cationically polymerizable monomer include vinyl ether compounds, epoxy compounds and oxetane compounds. Examples of the vinyl ether compound 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; butanediol-1,4. -Examples include polyfunctional vinyl ethers such as divinyl ethers, triethylene glycol divinyl ethers and dipropylene glycol divinyl ethers.

Examples of the epoxy compound include aromatic epoxy compounds, alicyclic epoxy compounds and aliphatic epoxy compounds. Examples of the aromatic epoxy compound include bisphenol diglycidyl ether compounds (bisphenol type epoxy resins) such as bisphenol A, bisfer F, and bisphenol S; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac epoxy resin, and the like. Novolac type epoxy resin; glycidyl ether compound of polyalcohol such as tetrahydroxyphenylmethane, tetrahydroxybenzophenone, polyvinylphenol and the like.

Examples of the alicyclic epoxy compound include vinylcyclohexene dioxide, 3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, limonendioxide, bis (3,4-epoxycyclohexylmethyl) adipate, and the like. Dicyclopentadiene diepoxide, bicyclopentadiene diepoxide, tricyclopentadiene diepoxide, dodecahydro-2,6-methano-2H-oxylano [3', 4'] cyclopenta [1', 2': 6,7] naphthus [ 2,3-b] Oxyrane and the like can be mentioned.

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, and propylene glycol diglycidyl ether. , Neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether and the like.

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

Examples of the anionic polymerizable monomer include (meth) acrylic acid ester. As the (meth) acrylic acid ester as the anionic polymerizable monomer, the above-mentioned radical polymerizable monomer can be used.

The polymer P preferably contains a structural unit derived from a polyfunctional monomer. Examples of the polyfunctional monomer include the above-mentioned polyfunctional (meth) acrylic acid ester, polyfunctional vinyl ether compound, polyfunctional epoxy compound, and polyfunctional oxetane compound. The content of the structural unit derived from the polyfunctional monomer 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 in some cases 70% by weight. It may be the above. The upper limit of the content of the structural unit derived from the polyfunctional monomer is not particularly limited, and is, for example, 95% by weight.

The polymer P may contain a structural unit derived from a monomer having a polar group, but preferably does not contain it. When the polymer P contains a structural unit derived from a monomer having a polar group, iodine contained in the polarizer 1 tends to easily approach the resin layer 2. Therefore, the content of the structural unit derived from the monomer having a polar group in the polymer P is preferably 20% by weight or less, more preferably 10% by weight or less, still more preferably 5% by weight or less. Particularly preferably, it is 2% by weight or less.

The resin layer 2 contains, for example, the 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 comprises 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.

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. The thickness of the resin layer 2 is preferably 0.3 μm or more, and may be 0.5 μm or more, from the viewpoint of sufficiently suppressing the permeation of iodine contained in the polarizer 1 to the outside.

The resin layer 2 may be attached to the polarizer 1 via an adhesive layer or an easy-adhesion layer. Examples of the adhesive layer for adhering the resin layer 2 to the polarizer 1 include those exemplified for the adhesive layer 3 described later. The easy-adhesion layer can be formed of, for example, a resin containing a polymer having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based material, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like. The polymer contained in the resin may be one kind or two or more kinds. The easy-adhesion layer may contain additives. Examples of the additive include a tackifier, an ultraviolet absorber, an antioxidant, a stabilizer such as a heat-resistant stabilizer, and the like. The thickness of the easy-adhesion 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-adhesion layer may be a laminate of a plurality of layers.

[Adhesive layer]
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. Examples of the adhesive contained in the adhesive layer 3 include a water-based adhesive and an active energy ray-curable adhesive. As the active energy ray-curable adhesive, for example, those disclosed in JP-A-2019-147685, JP-A-2016-177248 and the like can be used.

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 even more preferably. It is 0.5 to 1.5 μm. If the thickness of the adhesive layer 3 is too small, the cohesive force of the adhesive layer 3 may be insufficient and the peeling force may decrease. If the thickness of the adhesive layer 3 is too large, when stress is applied to the cross section of the polarizing film 10, peeling may occur in the adhesive layer 3. That is, in the polarizing film 10, peeling failure due to impact may occur.

[Transparent protective film]
The transparent protective film 4 is preferably one having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property, and the like. Examples of the material of the transparent protective film 4 include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; (meth) acrylic polymers such as polymethyl methacrylate; polystyrene and acrylonitrile. -Sterite-based polymer such as styrene copolymer (AS resin); Polycarbonate-based polymer; Olefin-based polymer such as polyethylene, polypropylene, ethylene-propylene copolymer; Cyclic olefin-based polymer such as polynorbornene; Vinyl chloride-based polymer; Nylon Amido-based polymers such as aromatic polyamides; imide-based polymers; sulfone-based polymers; polyether sulfone-based polymers; polyether ether ketone-based polymers; polyphenylene sulfide-based polymers; vinyl alcohol-based polymers; vinylidene chloride-based polymers; vinyl butyral-based polymers Arilate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; mixtures of these polymers and the like.

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% by weight to 100% by weight, more preferably 50% by weight to 99% by weight, and further preferably 60% by weight to 98% by weight. Particularly preferably, it is 70% by weight 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 inherent in the thermoplastic resin may not be sufficiently exhibited.

The transparent protective film may contain one or more kinds of additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an antioxidant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent and the like.

The transparent protective film 4 may be a polymer film described in JP-A-2001-343529, International Publication No. 01/37007, and the like. Examples of the material of this polymer film include a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, a thermoplastic resin having a substituted and / or unsubstituted phenyl group in the side chain, and a nitrile group. Examples thereof include a resin composition containing. Specific examples of this polymer film include a film formed from a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. This film is obtained, for example, by mixing and extruding a resin composition. Since this film has a small phase difference and a small photoelastic coefficient, it is possible to eliminate problems such as unevenness due to distortion of the polarizing film 10. Further, since this film has low moisture permeability, it has excellent durability in a humid environment.

The moisture permeability of the transparent protective film 4 is not particularly limited, ^{but is preferably 150 g / m 2} / 24h or less. In this case, it is possible to suppress the invasion of moisture in the air into the polarizing film 10, and it is possible to suppress the change in the moisture content of the polarizing film 10. As a result, it is possible to suppress the occurrence of curling and dimensional change of the polarizing film 10 during storage and the like. Examples of the material for forming the transparent protective film 4 having low moisture permeability include polyester-based polymers, polycarbonate-based polymers, allylate-based polymers, amide-based polymers, olefin-based polymers, cyclic olefin-based polymers, (meth) acrylic-based polymers, and materials. Examples of these are mixtures. As the material for forming the transparent protective film 4, a polycarbonate polymer, a cyclic olefin polymer and a (meth) acrylic polymer are preferable, and a cyclic olefin polymer and a (meth) acrylic polymer are particularly preferable.

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, handleability, and the like.

The surface of the transparent protective film 4 may be subjected to an easy-adhesion treatment such as a corona treatment or a plasma treatment in order to improve the adhesion between the members. An easy-adhesion layer may be arranged on the surface of the transparent protective film 4. As the easy-adhesion layer, the resin layer 2 described above can be used.

[Adhesive layer]
The pressure-sensitive adhesive layer 5 is a layer containing a pressure-sensitive adhesive. The material of the pressure-sensitive adhesive is not particularly limited, and for example, a material containing (meth) acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based polymer, rubber-based polymer, etc. as a base polymer is used. Can be done. In particular, an acrylic pressure-sensitive adhesive containing a (meth) acrylic polymer has excellent optical transparency, has adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness, and is excellent in weather resistance, heat resistance, and the like. , Suitable for the material of the pressure-sensitive adhesive layer 5.

The pressure-sensitive adhesive layer 5 may be a laminate of a plurality of layers having different compositions. The thickness of the pressure-sensitive adhesive layer 5 is appropriately determined according to the purpose of 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 pressure-sensitive adhesive layer 5 may be 50 μm or less.

Before the polarizing film 10 is attached to the image display panel, the pressure-sensitive adhesive layer 5 may be attached to the separator. According to the separator, contamination of the pressure-sensitive adhesive layer 5 can be prevented. Examples of the separator include silicone-based, long-chain alkyl-based, and fluorine-based separators for thin films such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof. , A coating treatment with a release agent such as molybdenum sulfide can be used.

[Other members]
The polarizing film 10 may further include members other than the above-mentioned members. The polarizing film 10 may further include, for example, a transparent substrate located on the visual side of the resin layer 2. The transparent substrate may be located on the outermost side of the polarizing film 10. The transparent substrate is made of, for example, glass or polymer. Examples of the polymer constituting the transparent substrate include polyethylene terephthalate, polycycloolefin, and polycarbonate. 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 the polymer is, for example, 10 μm to 200 μm.

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

The polarizing film 10 may further include an optical film such as a reflecting plate, an antitransmissive plate, a retardation film, a viewing angle compensating film, and a brightness improving film. The retardation film includes, for example, a 1/2 wave plate, a 1/4 wave plate, and the like. In the polarizing film 10, the retardation film may be arranged on the image display panel side (for example, between the pressure-sensitive adhesive layer 5 and the transparent protective film 4) of the polarizing element 1, and is on the visual side of the polarizing element 1. It may be arranged in.

The polarizing film 10 may further include functional layers such as a hard coat layer, an antireflection layer, a sticking prevention layer, a diffusion layer, and an antiglare layer. In the polarizing film 10, the hard coat layer may be arranged on the visual side of the resin layer 2.

[Manufacturing method of polarizing film]
The polarizing film 10 can be produced, for example, by the following method. First, the polarizer 1 and the transparent protective film 4 are bonded together via the adhesive layer 3. Next, a coating liquid containing the monomer M for forming the polymer P and the polymerization initiator is prepared. The polymerization initiator can be appropriately selected depending on the monomer M contained in the coating liquid. As an example, when the coating liquid contains a radically polymerizable monomer, a photopolymerization initiator can be used as the polymerization initiator. When the coating liquid contains a cationically polymerizable monomer, a photoacid generator can be used as the polymerization initiator.

Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3′-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-). Aromatic ketone compounds such as propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone; methoxyacetophenone, 2,2-dimethoxy-2 -Acetphenone compounds such as phenylacetophenylone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropan-1-one; benzophenone methyl ether , Benzophenone ethyl ether, benzoin isopropyl ether, benzoine butyl ether, anisoin methyl ether and other benzoin ether compounds; aromatic ketal compounds such as benzyl dimethyl ketal; 2-naphthalene sulfonyl chloride and other aromatic sulfonyl Chloride compounds; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone , Isoxanthone compounds such as isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; benzophenone; halogenated ketone; acylphosphinoxide; acylphosphonate, etc. Can be mentioned.

Examples of the photoacid generator include compounds represented by the following formula (i).
L ⁺ X ^- (i)

In the formula (i), L ⁺ is an onium cation, X ^- _{^{_{^{is, PF 6 -, SbF 6 -}}}} , AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate anion and SCN ^- a counter anion selected from the group consisting of.

Specific examples of the photoacid generator include "Cyracure UVI-6992", "Cyracure UVI-6974" (all manufactured by Dow Chemical Japan Co., Ltd.), "Adeka Putmer SP150", and "Adeka Putmer". SP152 ”,“ ADEKA PUTMER SP170 ”,“ ADEKA PTMER SP172 ”(above, ADEKA Corporation),“ IRGACURE250 ”(manufactured by Ciba Specialty Chemicals),“ CI-5102 ”,“ CI-2855 ”(above) , Made by Nippon Soda), "Sun Aid SI-60L", "Sun Aid SI-80L", "Sun Aid SI-100L", "Sun Aid SI-110L", "Sun Aid SI-180L" (all manufactured by Sanshin Chemical Co., Ltd.) , "CPI-100P", "CPI-100A" (all manufactured by Sun Appro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044" , "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (all manufactured by Wako Junyaku Co., Ltd.).

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, still more preferably 0.1. ~ 5% by weight.

Next, the coating liquid is applied onto the polarizer 1. As a result, a film (coating film) containing the monomer M and the polymerization initiator can be formed on the polarizer 1. Next, the monomer M is polymerized so that the resin layer 2 is formed from the coating film. The polymerization of the monomer M can be carried out by a known method. For example, when a photopolymerization initiator or a photoacid generator is used as the polymerization initiator, the monomer M can be polymerized by irradiating the coating film with active energy rays. Examples of the active energy ray include visible light and ultraviolet light. In the present specification, the resin layer 2 produced by polymerizing the monomer M contained in the coating film may be referred to as a cured resin layer. Next, the polarizing film 10 is obtained by adhering the pressure-sensitive adhesive layer 5 to the transparent protective film 4.

The resin layer 2 may be produced 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. Examples of the solvent include an organic solvent capable of dissolving or dispersing the polymer P. Next, a coating film is produced by applying the coating liquid onto the polarizer 1. The resin layer 2 is obtained by drying the coating film.

[Characteristics of polarizing film]
In the polarizing film 10 of the present embodiment, at least one of the above requirements (i) to (v) is satisfied, so that iodine contained in the polarizing element 1 is sufficiently permeated to the outside in a high temperature and high humidity environment. It is suppressed. That is, in a high temperature and high humidity environment, the iodine concentration in the polarizer 1 hardly changes. The change in the iodine concentration in the polarizer 1 can be read from, for example, the change in the simple substance transmittance of the polarizing film 10. As an example, when the polarizing film 10 is attached to non-alkali glass via the pressure-sensitive adhesive layer 5 and the polarizing film 10 is placed in an atmosphere of 65 ° C. and 90% RH for 24 hours, the polarizing film 10 is transmitted as a single unit. The change in rate ΔY1 is, for example, 5 or less, preferably 4 or less, more preferably 2 or less, still more preferably 1.5 or less, and particularly preferably 1 or less.

Specifically, the change ΔY1 of the simple substance transmittance can be measured by the following method. First, the simple substance transmittance Ts1 of the laminate obtained by laminating the polarizing film 10 to the non-alkali glass via the pressure-sensitive adhesive layer 5 is measured. The laminate is then placed in an atmosphere of 65 ° C. and 90% RH for 24 hours. The simple substance transmittance Ts2 is measured for the laminated body after being placed in this atmosphere. The value obtained by subtracting the single transmittance Ts1 from the single transmittance Ts2 is regarded as the change ΔY1 of the single transmittance. The single transmittance of the laminated body is a Y value obtained by correcting the luminosity factor with a two-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 Laboratory. The measurement wavelength of the simple substance transmittance is 380 to 700 nm (every 10 nm). The non-alkali glass is a glass that does not substantially contain an alkaline component (alkali metal oxide), and more specifically, the weight ratio of the alkaline component in the glass is, for example, 1000 ppm or less, and further 500 ppm or less. The non-alkali glass is, for example, plate-shaped and has a thickness of 0.5 mm or more.

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.

(Modification example of polarizing film)
In the polarizing film 10, the resin layer 2 may be located closer to the image display panel, which will be described later, than the polarizing element 1. As shown in FIG. 2, in the polarizing film 11 according to this modification, the resin layer 2 is located closer to the image display panel than the polarizer 1. The structure of the polarizing film 11 is the same as that of the polarizing film 10 except for the position of the resin layer 2. Therefore, the same reference numerals may be given to the elements common to the polarizing film 10 and the polarizing film 11 of the modified example, and the description thereof may be omitted. That is, the following description of each embodiment applies to each other as long as there is no technical contradiction. The following embodiments may be combined with each other as long as they are not technically inconsistent.

The resin layer 2 is located between the polarizer 1 and the adhesive layer 3, for example, and is in direct contact with each of the polarizer 1 and the adhesive layer 3. However, another layer such as an adhesive layer or an easy-adhesion layer may be arranged between the resin layer 2 and the polarizer 1. For example, the resin layer 2 may be attached to the polarizer 1 via an adhesive layer or an easy-adhesion layer. Examples of the adhesive layer and the easy-adhesive layer for adhering the resin layer 2 to the polarizing element 1 include those described above for the polarizing film 10. When the resin layer 2 is located closer to the image display panel than the polarizing element 1, iodine contained in the polarizing element 1 moves to the pressure-sensitive adhesive layer 5 in a high-temperature and high-humidity environment, and the polarizing film 11 passes through the pressure-sensitive adhesive layer 5. It is possible to suppress permeation to the outside.

(Another variant of the polarizing film)
The polarizing film 10 may further include members other than the above-mentioned members. As shown in FIG. 3, the polarizing film 12 according to this modification further includes a transparent protective film (second transparent protective film) 6. Except for the second transparent protective film 6, the structure of the polarizing film 12 is the same as that of the polarizing film 10. Therefore, the same reference numerals may be given to the elements common to the polarizing film 10 and the polarizing film 12 of the modified example, and the description thereof may be omitted.

The second transparent protective film 6 is located on the visual side of 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, for example, on the visual side of the resin layer 2 and is located on the outermost side of the polarizing film 12. However, when the polarizing film 12 includes the above-mentioned transparent substrate, the second transparent protective film 6 may be located between the resin layer 2 and the transparent substrate. The second transparent protective film 6 is in direct contact with, for example, the resin layer 2. However, the second transparent protective film 6 may be attached to the resin layer 2 via another layer such as an adhesive layer or a hard coat layer. Examples of the adhesive layer for adhering the second transparent protective film 6 to the resin layer 2 include those described above for the adhesive layer 3.

As the second transparent protective film 6, the one 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 as each other or may be different from each other.

The polarizing film 12 provided with the second transparent protective film 6 tends to further suppress the permeation 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 attached to non-alkali glass via the pressure-sensitive adhesive layer 5 and the polarizing film 12 is placed in an atmosphere of 65 ° C. and 90% RH for 120 hours, the polarizing film 12 is transmitted as a single unit. The change in rate ΔY2 is, for example, 3 or less, preferably 2 or less, more preferably 1.5 or less, still more preferably 1 or less, and particularly preferably 0.8 or less.

Specifically, the change ΔY2 of the simple substance transmittance can be measured by the following method. First, the simple substance transmittance Ts3 of the laminate obtained by laminating the polarizing film 12 to the non-alkali glass via the pressure-sensitive adhesive layer 5 is measured. Next, the laminate is placed in an atmosphere of 65 ° C. and 90% RH for 120 hours. The simple substance transmittance Ts4 is measured for the laminated body after being placed in this atmosphere. The value obtained by subtracting the single transmittance Ts3 from the single transmittance Ts4 is regarded as the change ΔY2 of the single transmittance.

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.

(Another modification of the polarizing film)
The polarizing film 10 may include two or more resin layers 2. As shown in FIG. 4, the polarizing film 13 according to this modification 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 may be given to the elements common to the polarizing film 10 and the polarizing film 13 of the modified example, and the description thereof may be omitted.

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 than the polarizer 1 (for example, between the polarizer 1 and the adhesive layer 3). When the polarizing element 1 is arranged between the two

resin layers

2a and 2b, the polarizing film 13 tends to further suppress the permeation of iodine contained in the polarizing element 1 to the outside.

The resin layer 2b may be in direct contact with the polarizer 1. However, another layer such as an adhesive layer or an easy-adhesion layer may be arranged between the resin layer 2b and the polarizer 1. For example, the resin layer 2b may be attached to the polarizer 1 via an adhesive layer or an easy-adhesion layer. Examples of the adhesive layer and the easy-adhesive layer for adhering the resin layer 2b to the polarizer 1 include those described above for the polarizing film 10.

(Embodiment of image display device)
As shown in FIG. 5, 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, the

polarizing film

11, 12 or 13 can be used instead of the polarizing film 10. In the image display device 100, the polarizing film 10 is attached to the image display panel 20 via, for example, the adhesive layer 5. Examples of the image display panel 20 include an organic EL display panel and a liquid crystal display panel, and an organic EL display panel is preferable.

The image display device 100 further includes, for example, a lighting system (not shown). As an example, the polarizing film 10, the image display panel 20, and the lighting system are arranged in this order, and the polarizing film 10 is located on the most visible side. The lighting system has, for example, a backlight or a reflector and irradiates the image display panel 20 with light.

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

<Thin polarizer>
First, a laminate in which a PVA layer having a thickness of 9 μm was formed on an amorphous polyethylene terephthalate (PET) substrate was prepared. A stretched laminate was produced by performing auxiliary stretching in the air at a stretching temperature of 130 ° C. for this laminate. Next, the stretched laminate was dyed with iodine to obtain a colored laminate. Further, the colored laminate was stretched in a boric acid aqueous solution at a stretching temperature of 65 ° C. to obtain a laminate in which the amorphous PET base material and the PVA layer were integrally stretched. In the laminated body, the total draw ratio was 5.94 times, and the thickness of the PVA layer was 5 μm. The PVA molecules in the PVA layer formed on the amorphous PET substrate by the above two-step stretching were oriented to a higher order. Furthermore, the iodine adsorbed by staining was oriented in a higher order in one direction as a polyiodine ion complex. The PVA layer contained in the laminate functioned as a thin polarizer.

<Transparent protective film>
First, a resin (imidized MS resin) composed of an imidized methyl methacrylate-styrene copolymer was prepared by the method described in Production Example 1 of JP-A-2010-284840. Next, using a twin-screw kneader, 100 parts by weight of the imidized MS resin and 0.62 parts by weight of a triazine-based ultraviolet absorber (trade name: T-712) were mixed at 220 ° C. to pellet the resin. Was produced. The obtained resin pellets were dried in an environment of 100.5 kPa and 100 ° C. for 12 hours. Next, a film having a thickness of 160 μm was produced by extruding the resin pellets from the T-die at a die temperature of 270 ° C. using a single-screw extruder. Further, this film was stretched in the transport direction in an atmosphere of 150 ° C., and the thickness was adjusted to 80 μm. Next, an easy-adhesive containing an aqueous urethane resin was applied to the film, and then the film was stretched in an atmosphere of 150 ° C. in a direction orthogonal to the transport direction to obtain a transparent protective film having a thickness of 40 μm. The moisture permeability of this transparent protective film was 58 g / m ² / 24h.

<Active energy ray-curable adhesive composition>
12 parts by weight of hydroxyethyl acrylamide (manufactured by KJ Chemicals, trade name: HEAA), 24 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toa Synthetic Co., Ltd., trade name: ARONIX M-5700), 12 parts by weight Hydroxypivalate 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 acrylic oligomer (manufactured by Toa Synthetic Co., Ltd., trade name: ARUFON UP-1190), 3 parts by weight 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane- 1-ON (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) are mixed and stirred for 3 hours. To obtain an active energy ray-curable adhesive composition.

<Laminated body containing transparent protective film, adhesive layer and thin polarizing element>
Using an MCD coater manufactured by Fuji Kikai Co., Ltd. (cell shape: honeycomb, number of gravure rolls: 1000 lines / inch, rotation speed 140% / pair of lines), the active energy ray-curable adhesive composition is applied to a transparent protective film. The bonded surface was coated. The thickness of the obtained coating film was 0.7 μm. Next, the transparent protective film and the laminate containing the PVA layer were bonded together using a roll machine. At this time, the coating film and the PVA layer were brought into contact with each other. The line speed of the roll machine was 25 m / min. Next, the obtained laminate was irradiated with active energy rays from the transparent protective film side. As the active energy ray, visible light emitted from a visible light irradiator (Light Hammer 10 manufactured by Fusion UV Systems) was used. The light source of the visible light irradiator was a gallium-filled metal halide lamp. In the visible light irradiation device, a V bulb was used as the bulb. The peak illuminance of the emitted light from the visible light irradiator was 1600 mW / cm ² . In the wavelength range of 380 nm to 440 nm, the integrated irradiation amount of the emitted light from the visible light irradiator was 1000 mJ / cm ² . The illuminance of the light emitted from the visible light irradiator was measured using a Solar-Check system manufactured by Solartell. By irradiating the laminate with active energy rays, the active energy ray-curable adhesive composition in the coating film was cured. Next, this laminate was dried with hot air at 70 ° C. for 3 minutes to obtain a laminate a containing a transparent protective film, an adhesive layer, and a thin polarizing element.

[Example 1]
(Polarizing film A)
First, 50 parts by weight of dicyclopentanyl acrylate (manufactured by Hitachi Kasei Co., Ltd., trade name: Funkryl FA-513AS), 50 parts by weight of dimethylol-tricyclodecane diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: light acrylate DCP) -A), 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- A coating solution was prepared by mixing diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYACURE DETX-S).

Next, the amorphous PET base material adjacent to the PVA layer was removed from the above-mentioned laminate a. The above coating liquid was applied onto the exposed PVA layer using Select Roller # 0 (manufactured by OSG System Products Co., Ltd.). The thickness of the obtained coating film was 1 μm. Next, the monomer was polymerized by irradiating the coating film with visible light under a nitrogen stream using the above-mentioned visible light irradiation device. The coating film was cured by the polymerization of the monomers, and a resin layer was formed.

Next, the surface of the transparent protective film was subjected to corona treatment. An adhesive layer having a thickness of 20 μm was attached to this surface. The pressure-sensitive adhesive layer was composed of an acrylic pressure-sensitive adhesive. As a result, a polarizing film A including a resin layer, a polarizing element, an adhesive layer, a transparent protective film, and an adhesive layer was obtained in this order.

(Polarizing film B)
First, a coating liquid was prepared by the same method as that of the polarizing film A. Using an MCD coater manufactured by Fuji Machinery Co., Ltd. (cell shape: honeycomb, number of gravure rolls: 700 lines / inch, rotation speed 140% / pair of lines), a 20 μm-thick triacetyl cellulose (TAC) film is bonded. The coating liquid was applied to the surface. The thickness of the obtained coating film was 1 μm. Next, the amorphous PET base material adjacent to the PVA layer was removed from the above-mentioned laminate a. The TAC film and the laminate a were bonded together using a roll machine. At this time, the coating film and the PVA layer were brought into contact with each other. The line speed of the roll 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, visible light emitted from 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. The coating film was cured by the polymerization of the monomers. Next, this laminate was dried with hot air at 70 ° C. for 3 minutes. As a result, a resin layer was formed.

Next, the surface of the transparent protective film containing the imidized MS resin was subjected to corona treatment. An adhesive layer having a thickness of 20 μm was attached to this surface. The pressure-sensitive adhesive layer was composed of an acrylic pressure-sensitive adhesive. As a result, the TAC film (second transparent protective film), the resin layer, the polarizer, the adhesive layer, the transparent protective film containing the imidized MS resin (the first transparent protective film), and the pressure-sensitive adhesive layer are provided in this order. Film B was obtained.

[Example 2-10 and Comparative Example 1]
The polarizing films A of Examples 2-10 and Comparative Example 1 and the polarizing film A of Comparative Example 1 were carried out by the same method as in Example 1 except that the monomer contained in the coating liquid for forming the resin layer was changed to the monomer shown in Table 1. B was prepared.

[Comparative Example 2]
The polarizing films A and B of Comparative Example 2 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. The photocurable resin composition B contains 12 parts by weight of hydroxyethylacrylamide (manufactured by KJ Chemicals, trade name: HEAA) and 20 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toa Synthetic Co., Ltd.). Name: ARONIX M-5700), 12 parts by weight of 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 Toa Synthetic Co., Ltd., trade name: ARUFON UP-1190), 5 parts by weight of diethylacrylamide (manufactured by KJ Chemicals) , Trade name: DEAA), 3 parts by weight 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907) and 3 parts by weight 2 , 4-Diethylthioxanthone (manufactured by Nippon Kayakusha Co., Ltd., trade name: KAYACURE DETX-S).

[Comparative Example 3]
The polarizing films A and B of Comparative Example 3 were prepared by the same method as in Example 1 except that the photocurable resin composition A was used as the coating liquid for forming the resin layer. The photocurable resin composition A contains 43 parts by weight of acryloyl morpholine (manufactured by KJ Chemicals, trade name: ACMO) and 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 P2HA), 10 parts by weight of acrylic oligomer (manufactured by Toa Synthetic Co., Ltd., trade name: ARUFON UP-1190) , 2 parts by weight 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (manufactured by IGM Resins, trade name: OMNIRAD 907) and 2 parts by weight 2,4-diethylthioxanthone (2 parts by weight) It was a mixture of KAYACURE DETX-S) manufactured by Nippon Kayakusha.

<Change in single transmittance ΔY1>
For the polarizing films A of Examples and Comparative Examples, the change ΔY1 of the single transmittance was measured by the following method. First, the polarizing film A was attached to the non-alkali glass via the pressure-sensitive adhesive layer. The simple substance transmittance Ts1 was measured for the obtained laminated body. The single transmittance Ts1 was measured using a spectral transmittance measuring device 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. For the laminated body after being placed in this atmosphere, the single transmittance Ts2 was measured using the above-mentioned spectral transmittance measuring device. By subtracting the single transmittance Ts1 from the single transmittance Ts2, the change ΔY1 of the single transmittance was calculated.

<Change in single transmittance ΔY2>
For the polarizing films B of Examples and Comparative Examples, the change ΔY2 of the single transmittance was measured by the following method. First, the polarizing film B was attached to the non-alkali glass via the pressure-sensitive adhesive layer. The simple substance transmittance Ts3 was measured for the obtained laminated body. The single transmittance Ts3 was measured using a spectral transmittance measuring device 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. For the laminated body after being placed in this atmosphere, the single transmittance Ts4 was measured using the above-mentioned spectral transmittance measuring device. By subtracting the single transmittance Ts3 from the single transmittance Ts4, the change ΔY2 of the single transmittance was calculated.

<Tension storage elastic modulus E1 and E2>
With respect to the resin layers used in Examples and Comparative Examples, the tensile storage elastic moduli E1 and E2 were measured by the method described above. As the dynamic viscoelasticity measuring device, the dynamic viscoelasticity measuring device RSA-G2 manufactured by TA Instruments was used.

<Linear expansion coefficients α1 and α2>
For the resin layers used in Examples and Comparative Examples, the linear expansion coefficients α1 and α2 were measured by the method described above. As the thermomechanical analyzer, a thermomechanical analyzer TMA 4000 SE manufactured by Netch Co., Ltd. was used.

<Dipole moment D>
The dipole moment D was calculated by the method described above for the monomers contained in the coating liquid for forming the resin layer used in Examples and Comparative Examples. For the calculation of the dipole moment D, Materials Studio (manufactured by BIOVIA, ver.8.0.0.843) and WebMO (ver.19.0.009e) were used.

The abbreviations in Table 1 are as follows.
FA513AS: Dicyclopentanyl acrylate, Hitachi Kasei TBCHA: 4-t-butylcyclohexyl acrylate, KJ Chemicals LA: Lauryl acrylate, Kyoei Chemicals ACMO: Acryloylmorpholine, KJ Chemicals DCP-A: Dimethylol-tricyclodecanediacrylate, Kyoeisha Chemical Co., Ltd. TMP-A: Trimethylolpropane triacrylate, Kyoeisha Chemical Co., Ltd. PE-4A: Pentaerythritol tetraacrylate, Kyoeisha Chemical Co., Ltd. DPE-6A: Dipentaerythritol hexaacrylate, Kyoeisha 1,9ND-A manufactured by Kagaku Co., Ltd .: 1,9-nonanediol diacrylate, manufactured by Kyoeisha Kagaku Co., Ltd.

As can be seen from Table 1, in the polarizing film A of the example in which at least one of the requirements (i) to (v) is satisfied, the change ΔY1 of the simple substance transmittance is 5 or less, and the outside of iodine in a high temperature and high humidity environment. Permeation to iodine was sufficiently suppressed. Similarly, in the polarizing film B of the example, the change ΔY2 of the simple substance transmittance was 3 or less, and the permeation of iodine to the outside in a high temperature and high humidity environment was sufficiently suppressed. On the other hand, in the polarizing films A and B of the comparative examples in which none of the requirements (i) to (v) is satisfied, the change in the single transmittance is larger than that in the examples, and the permeation of iodine to the outside in a high temperature and high humidity environment. Could not be sufficiently suppressed.

The polarizing film of the present invention can be suitably used for mobile displays such as mobile phones, smartphones and laptop computers; and in-vehicle displays such as car navigation device panels, cluster panels and mirror displays.

Claims

With a polarizer containing iodine,
With a resin layer containing a polymer,
A polarizing film that meets at least one of the following requirements (i) to (v).
(I) a tensile storage modulus E1 of the resin layer at 65 ° C. in water is 1 × 10 8 Pa or more.
(Ii) tensile storage modulus E2 of the resin layer at 85 ° C. in water is 1 × 10 8 Pa or more.
(Iii) When the resin layer is heated from 25 ° C. to 65 ° C. and the measurement atmosphere is further humidified from 10% RH to 90% RH, the linear expansion coefficient α1 of the resin layer is 400 × 10 -6 / K or less. be.
(Iv) When the resin layer is heated from 25 ° C. to 85 ° C. and the measurement atmosphere is further humidified from 10% RH to 85% RH, the linear expansion coefficient α2 of the resin layer is 300 × 10 -6 / K or less. be.
(V) The dipole moment D of the monomer for forming the polymer is 2 Debye or less.
The polarizing film according to claim 1, wherein the coefficient of linear expansion α1 of the resin layer is 180 × 10 -6 / K or less.
The polarizing film according to claim 1 or 2, wherein the polymer contains a structural unit derived from a (meth) acrylic acid ester.
The polarizing film according to claim 3, wherein the content of the structural unit derived from the (meth) acrylic acid ester in the polymer is higher than 70% by weight.
The polarizing film according to any one of claims 1 to 4, wherein the polymer contains a structural unit derived from a polyfunctional monomer.
The polarizing film according to claim 5, wherein the content of the structural unit derived from the polyfunctional monomer in the polymer is 20% by weight or more.
The polarizing film according to any one of claims 1 to 6, wherein the content of the structural unit derived from the monomer having a polar group in the polymer is 20% by weight or less.
The polarizing film according to any one of claims 1 to 7, wherein the resin layer is located on the visual side of the polarizing element.
The polarizing film according to any one of claims 1 to 8, wherein the resin layer is in direct contact with the polarizing element.
The two resin layers are provided, and the resin layer is provided.
The polarizing film according to any one of claims 1 to 7, wherein the polarizing element is located between two resin layers.
Further provided with an adhesive layer and a first transparent protective film,
The polarizing film according to any one of claims 1 to 10, wherein the polarizing element, the adhesive layer, and the first transparent protective film are arranged in this order in the stacking direction.
With a second transparent protective film
The polarizing film according to claim 11, wherein the polarizing element is located between the first transparent protective film and the second transparent protective film.
With an additional adhesive layer,
The polarizing film according to any one of claims 1 to 12, wherein the polarizing element is located on the visual side of the pressure-sensitive adhesive layer.
The polarizing film according to any one of claims 1 to 13 and the polarizing film.
Image display panel and
An image display device equipped with.