WO2023053798A1 - Polarization film, image display device, and method for producing polarization film - Google Patents

Abstract

The present invention provides a polarization film that can satisfactorily suppress the outward permeation in a high-temperature, high-humidity environment of the iodine contained in a polarizer. The polarization film according to the present invention comprises an iodine-containing polarizer and a resin layer comprising a polymer that has at least one selection from the group consisting of a structural unit U1 derived from an epoxy group-containing compound A1 and a structural unit U2 derived from an oxetane group-containing compound A2. The value of y calculated from formula (1) for the polarization film is less than 4.00. (1): y = (-3.71)x1 + (-3.94)x2 + (0.299)x3 + (0.266)x4 + (-1.05)x5 + (0.517)x6 + (0.769)x7 + 71.81

Description

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

The present invention relates to a polarizing film, an image display device, and a method for manufacturing a polarizing film.

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. A polarizing film is, for example, a laminate including a polarizer and a protective film. A polarizer can generally be produced by adsorbing a dichroic dye to 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 bonding a protective film to a polarizer using an adhesive containing an epoxy compound. Specifically, in Patent Literature 1, the polarizer and the protective film are joined together by curing the applied layer in a state in which the polarizer and the protective film are overlaid with an adhesive applied layer interposed therebetween.

JP 2012-208250 A

In a hot and humid environment, the iodine contained in the polarizer tends to migrate from the polarizer to the protective film or the adhesive layer for bonding 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 migrate from the polarizer to the protective film or adhesive layer. The iodine that has migrated to the protective film or adhesive layer permeates to the outside of the polarizing film through the protective film or adhesive layer. When the content of iodine in the polarizer decreases, the degree of polarization of the polarizing film decreases. Conventional polarizing films cannot sufficiently prevent iodine contained in the polarizer from permeating to the outside of the polarizing film in a hot and humid environment.

Therefore, an object of the present invention is to provide a polarizing film suitable for sufficiently suppressing transmission of iodine contained in a polarizer to the outside in a hot and humid environment.

As a result of intensive studies, the present inventors newly discovered that the properties of the resin layer included in the polarizing film can be predicted based on the monomers for forming the polymer contained in the resin layer. According to studies by the present inventors, this prediction is particularly reliable for a resin layer containing a polymer having a structural unit derived from a compound containing an epoxy group or a structural unit derived from a compound containing an oxetane group. expensive. Based on this knowledge, the present inventors further studied and completed the present invention.

The present invention
a polarizer containing iodine;
A resin layer containing a polymer having at least one selected from the group consisting of a structural unit U1 derived from a compound A1 containing an epoxy group and a structural unit U2 derived from a compound A2 containing an oxetane group,
Provided is a polarizing film in which the value of y calculated by the following formula (1) is less than 4.00.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer for forming the polymer,
_x2 is the x component (Debye) in the dipole moment of the monomer to form the polymer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules to form the polymer;
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. (g/100 g) of the monomer to form the polymer;
_x5 is the dipole moment (Debye) of the monomer to form the polymer;
_x6 is the z component (Debye) in the dipole moment of the monomer to form the polymer;
_x7 is the number of hydrogen bond acceptors in the monomer to form the polymer.

Furthermore, the present invention
the above polarizing film;
an image display panel;
to provide an image display device.

Furthermore, the present invention
A resin layer containing a polymer having at least one selected from the group consisting of a polarizer containing iodine, a structural unit U1 derived from a compound A1 containing an epoxy group, and a structural unit U2 derived from a compound A2 containing an oxetane group. And, a method for producing a polarizing film comprising
The manufacturing method is
Provided is a method for producing a polarizing film, comprising the step of polymerizing a monomer having a y value of less than 4.00 calculated by the following formula (1) to obtain the polymer.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer,
_x2 is the x component (Debye) in the dipole moment of the monomer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules,
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. of the monomer (g/100 g);
x ₅ is the dipole moment (Debye) of the monomer,
x ₆ is the z component (Debye) in the dipole moment of the monomer,
_x7 is the number of hydrogen bond acceptors in the monomer.

According to the present invention, it is possible to provide a polarizing film suitable for sufficiently suppressing transmission of iodine contained in a polarizer to the outside in a hot and humid environment.

1 is a schematic cross-sectional view of a polarizing film according to one embodiment of the present invention; FIG. It is a schematic sectional drawing which shows the modification of a polarizing film. It is a schematic sectional drawing which shows another modification of a polarizing film. It is a schematic sectional drawing which shows another modification of a polarizing film. It is a schematic sectional drawing which shows another modification of a polarizing film. 1 is a schematic cross-sectional view of an image display device according to an embodiment of the present invention; FIG. It is the schematic of the polarizing film used for the crack evaluation test.

The polarizing film according to the first aspect of the present invention is
a polarizer containing iodine;
A resin layer containing a polymer having at least one selected from the group consisting of a structural unit U1 derived from a compound A1 containing an epoxy group and a structural unit U2 derived from a compound A2 containing an oxetane group,
The value of y calculated by the following formula (1) is less than 4.00.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer for forming the polymer,
_x2 is the x component (Debye) in the dipole moment of the monomer to form the polymer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules to form the polymer;
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. (g/100 g) of the monomer to form the polymer;
_x5 is the dipole moment (Debye) of the monomer to form the polymer;
_x6 is the z component (Debye) in the dipole moment of the monomer to form the polymer;
_x7 is the number of hydrogen bond acceptors in the monomer to form the polymer.

In the second aspect of the present invention, for example, in the polarizing film according to the first aspect, the value of y is 2.30 or less.

In the third aspect of the present invention, for example, in the polarizing film according to the first or second aspect, the polymer includes both the structural unit U1 and the structural unit U2.

In the fourth aspect of the present invention, for example, in the polarizing film according to any one of the first to third aspects, in the polymer, the content of the structural unit U1 and the content of the structural unit U2 The total value is 70% by weight or more.

In the fifth aspect of the present invention, for example, in the polarizing film according to any one of the first to fourth aspects, the compound A1 contains a ring structure other than an epoxy group.

In the sixth aspect of the present invention, for example, in the polarizing film according to any one of the first to fifth aspects, the compound A1 contains at least one selected from the group consisting of an aliphatic ring and an aromatic ring. .

In the seventh aspect of the present invention, for example, in the polarizing film according to any one of the first to sixth aspects, the resin layer contains an acid generator and/or a decomposition product of the acid generator.

In the eighth aspect of the present invention, for example, in the polarizing film according to any one of the first to seventh aspects, the resin layer is in direct contact with the polarizer.

In the ninth aspect of the present invention, for example, in the polarizing film according to any one of the first to eighth aspects, the thickness of the resin layer is less than 3 μm.

In the tenth aspect of the present invention, for example, in the polarizing film according to any one of the first to ninth aspects, the polarizer has a thickness of 1 μm or more and less than 7 μm.

In the eleventh aspect of the present invention, for example, in the polarizing film according to any one of the first to tenth aspects, the polarizer contains polyvinyl alcohol as a main component.

In the twelfth aspect of the present invention, for example, the polarizing film according to any one of the first to eleventh aspects further comprises a protective film.

In the 13th aspect of the present invention, for example, in the polarizing film according to the 12th aspect, the protective film, the resin layer, and the polarizer are arranged in this order in the stacking direction.

In the 14th aspect of the present invention, for example, in the polarizing film according to the 12th or 13th aspect, the protective film has a moisture permeability of 300 g/(m2·day) or more.

In the 15th aspect of the present invention, for example, in the polarizing film according to any one of the 12th to 14th aspects, the protective film contains triacetyl cellulose as a main component.

In the 16th aspect of the present invention, for example, in the polarizing film according to any one of the 12th to 15th aspects, the protective film has a thickness of less than 40 μm.

The image display device according to the seventeenth aspect of the present invention comprises
A polarizing film according to any one of the first to sixteenth aspects;
an image display panel;
Prepare.

The method for producing a polarizing film according to the eighteenth aspect of the present invention comprises:
A resin layer containing a polymer having at least one selected from the group consisting of a polarizer containing iodine, a structural unit U1 derived from a compound A1 containing an epoxy group, and a structural unit U2 derived from a compound A2 containing an oxetane group. And, a method for producing a polarizing film comprising
The manufacturing method is
The method includes a step of polymerizing a monomer having a y value of less than 4.00 calculated by the following formula (1) to obtain the polymer.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer,
_x2 is the x component (Debye) in the dipole moment of the monomer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules,
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. of the monomer (g/100 g);
x ₅ is the dipole moment (Debye) of the monomer,
x ₆ is the z component (Debye) in the dipole moment of the monomer,
_x7 is the number of hydrogen bond acceptors in the monomer.

Although the details of the present invention will be described below, the following description is not intended to limit the present invention to specific embodiments.

(Embodiment of polarizing film)
As shown in FIG. 1, the polarizing film 10 of this embodiment includes a polarizer 1 containing iodine and a resin layer 2 containing a polymer P. As shown in FIG. The polymer P contained in the resin layer 2 has at least one selected from the group consisting of the structural unit U1 derived from the compound A1 containing an epoxy group and the structural unit U2 derived from the compound A2 containing an oxetane group. The resin layer 2 is located, for example, on the viewing side of the polarizer 1 and is in direct contact with the polarizer 1 . However, between the resin layer 2 and the polarizer 1, other layers such as an adhesive layer and an easy-adhesion layer may be arranged within a range that does not interfere with the effects of the present invention. The resin layer 2 may be located closer to the image display panel (to be described later) than the polarizer 1 is. In other words, the polarizer 1 may be positioned closer to the viewer than the resin layer 2 is. The resin layer 2 is positioned, for example, on the outermost side of the polarizing film 10 . In this specification, the term "film" means a member whose thickness is sufficiently smaller than its length and width.

The polarizing film 10 may further include an adhesive layer 3, a protective film 4 and an adhesive layer 5. The protective film 4 is attached to the polarizer 1 via an adhesive layer 3, for example. The pressure-sensitive adhesive layer 5 functions, for example, as a member for bonding the polarizing film 10 to an image display panel, which will be described later. Therefore, the pressure-sensitive adhesive layer 5 is positioned, for example, on the outermost side of the polarizing film 10 and closer to the image display panel than the polarizer 1 is. In other words, the polarizer 1 is positioned, for example, on the viewing side of the pressure-sensitive adhesive layer 5 . The resin layer 2, the polarizer 1, the adhesive layer 3, the protective film 4, and the adhesive layer 5 are arranged in this order in the stacking direction, for example.

In the polarizing film 10 of this embodiment, the value of y calculated by the following formula (1) is less than 4.00.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )

In equation (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameters of the monomer M to form the polymer P. x ₁ can be an index for predicting the interaction that occurs between the polymer P and water molecules or iodine. The Hansen solubility parameters are obtained by dividing the solubility parameters introduced by Hildebrand into three components: the dispersion term δD, the polarization term δP, and the hydrogen bonding term δH. The dispersion term δD indicates the energy due to intermolecular dispersion forces. Details of the Hansen Solubility Parameters are disclosed in "Hansen Solubility Parameters; A Users Handbook" (CRC Press, 2007). The variance term δD can be calculated using known software such as HSPiP (version 5). Note that the value of the variance term δD may differ slightly depending on the software used. However, this error is usually of a size that can be ignored in calculating the value of y.

When the polymer P is formed from multiple types of monomers M, the value of _x1 can be specified by the following method. First, the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameters is calculated for each of the plurality of types of monomers M. The calculated dispersion term δD is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be regarded as _x1 . In this embodiment, the value of x ₁ is not particularly limited, and is, for example, 15 to 20 (MPa ^1/2 ), preferably 16.4 to 18.9 (MPa ^1/2 ).

x ₂ is the x component (Debye) in the dipole moment of the monomer M to form the polymer P; x ₂ can be an index for predicting the interaction that occurs between the polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity and humidification durability of the polymer P. The closer the value of _x2 is to 0, the smaller the dipole moment of the monomer M and the more hydrophobic the polymer P tends to be.

x ₂ can be identified, for example, by the following method. First, the monomer M for forming the polymer P is specified. By performing a molecular simulation for the monomer M, the x component in the dipole moment can be calculated. 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).

　Calculation of the x component in the dipole moment D by molecular simulation can be performed, for example, by the following method. First, a molecular model of the 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 employed to optimize the geometry. Next, the molecular model of monomer M is processed with WebMO. Specifically, in WebMO, a Gaussian program (Queue: g09) is used to perform structural optimization calculations for the molecular model of the monomer M. At this time, B3LYP may be used as the functional, and 6-31G(d) may be used as the basis function. Thereby, the x component in the dipole moment D of the monomer M can be calculated. It should be noted that the internal coordinates of each atom constituting the monomer M are defined by the Z-matrix format when the molecular simulation is performed. When the Z-matrix format is used, the x-, y-, and z-axes for determining the internal coordinates are automatically determined according to the structure of the monomer M.

When the polymer P is formed from multiple types of monomers M, x ₂ can be specified by the following method. First, for each of the multiple types of monomers M, the x component in the dipole moment is calculated by the method described above. The x component in the calculated dipole moment is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be taken as _x2 . Even when a plurality of types of monomers M are structural isomers of each other, the x component in the calculated dipole moment is weighted by the molar ratio of each structural isomer to perform a weighted average to specify x ₂ . can be done. In this embodiment, the value of x ₂ is not particularly limited, and is, for example, -1.0 to 1.0 Debye.

x ₃ is the interaction energy ΔE (kcal/mol) between the monomer M and the water molecule for forming the polymer P; x ₃ can be an index for predicting the interaction that occurs between the polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity and humidification durability of the polymer P.

x ₃ can be identified, for example, by the following method. First, the monomer M for forming the polymer P is specified. A molecular model of the monomer M is created by the method described above for x ₂ , and the structure optimization calculation is performed on the molecular model. From this, the potential energy _EM (kcal/mol) of the monomer M per molecule is calculated. Next, a molecular model of water molecules is created by a similar method, and the structure optimization calculation is performed for the molecular model. From this, the potential energy E _H2O (kcal/mol) of water molecule per molecule is calculated. Furthermore, a molecular model containing one molecule of monomer M and one molecule of water is created by a similar method. In this molecular model, a water molecule is arranged near the hydrogen bond acceptor contained in the monomer M. A structural optimization calculation is performed on this molecular model to calculate the potential energy E _M+H2O (kcal/mol) of the complex of the monomer M and the water molecule. Based on the calculated potential energy, _x3 can be specified by the following formula.
x ₃ (ΔE) = E _{M + H2O} - (E _M + E _H2O )

The hydrogen bond acceptor means an atom capable of forming a hydrogen bond with a hydrogen atom contained in a water molecule. Hydrogen bond acceptors include atoms with relatively high electronegativity such as oxygen atoms and nitrogen atoms. When the monomer M contains multiple hydrogen bond acceptors, the potential energy E _{M +H2O} can be determined by the following method. First, a plurality of molecular models containing one molecule of monomer M and one molecule of water are prepared. The number of molecular models corresponds to the number of hydrogen bond acceptors contained in one monomer M molecule. In multiple molecular models, hydrogen bond acceptors with which water molecules are placed in proximity are different from each other. Next, potential energy is calculated by performing structural optimization calculations for each of the plurality of molecular models. The average value of the obtained calculated values can be regarded as the potential energy E _{M +H2O} .

When the polymer P is formed from multiple types of monomers M, _x3 can be specified by the following method. First, the interaction energy ΔE with water molecules is calculated for each of a plurality of types of monomers M. The calculated interaction energy ΔE is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be taken as _x3 . In this embodiment, the value of x ₃ is not particularly limited and is, for example, -20 to 10 kcal/mol.

x ₄ is the common logarithmic value LogS of the solubility S (g/100 g) of the monomer M in water at 25° C. to form the polymer P; x ₄ can be an index for predicting the water solubility of the polymer P, that is, an index for predicting the degree of the polymer P's hydrophobicity and humidification durability. The solubility S specifically means the maximum weight (g) of the monomer M that can be dissolved in 100 g of water at 25°C.

LogS may be calculated using known software such as HSPiP (version 5). HSPiP can calculate the solubility of any compound and its common logarithm LogS using a multiple regression equation created based on the measured values of the solubility of many compounds. Solubility and LogS calculated using HSPiP are known to agree well with actual measurements.

When the polymer P is formed from multiple types of monomers M, _x4 can be identified by the following method. First, LogS is calculated for each of a plurality of types of monomers M. The calculated LogS is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be taken as _x4 . In this embodiment, the value of x ₄ is not particularly limited, and ranges from -5.0 to 10, for example.

x ₅ is the dipole moment (Debye) of the monomer M to form the polymer P; _x5 can be an index for predicting the interaction that occurs between the polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity and humidification durability of the polymer P. The closer the value of _x5 is to 0, the more hydrophobic the polymer P tends to be. _x5 can be calculated by the molecular simulations described above for _x2 . Note that the dipole moment is a vector quantity calculated from the x component, the y component, and the z component.

When the polymer P is formed from multiple types of monomers M, _x5 can be identified by the following method. First, the dipole moment is calculated for each of a plurality of types of monomers M. The calculated dipole moment is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be taken as _x5 . Even when a plurality of types of monomers M are structural isomers of each other, x ₅ can be specified by weighting the calculated dipole moments by the molar ratio of each structural isomer and performing a weighted average. In this embodiment, the value of x ₅ is not particularly limited, and is, for example, 2.0 to 5.0 Debye.

x ₆ is the z component (Debye) in the dipole moment of the monomer M to form the polymer P; x ₆ can be an index for predicting the interaction that occurs between the polymer P and water molecules, that is, an index for predicting the degree of hydrophobicity and humidification durability of the polymer P. The closer the value of _x6 is to 0, the more hydrophobic the polymer P tends to be. x ₆ can be calculated by the molecular simulations described above for x ₂ .

When the polymer P is formed from multiple types of monomers M, x ₆ can be specified by the following method. First, for each of a plurality of types of monomers M, the z component in the dipole moment is calculated. The z component in the calculated dipole moment is weighted by the molar ratio of each monomer M to obtain a weighted average. The weighted average obtained can be taken as _x6 . Even when a plurality of types of monomers M are structural isomers of each other, the z component in the calculated dipole moment is weighted by the molar ratio of each structural isomer and the weighted average is performed to specify x ₆ . can be done. In this embodiment, the value of _x6 is not particularly limited, and is, for example, -2.0 to 3.0 Debye.

_x7 is the number of hydrogen bond acceptors in monomer M to form polymer P; _x7 can be an index for predicting the water solubility of the polymer P, that is, an index for predicting the degree of the polymer P's hydrophobicity and humidification durability. As described above, a hydrogen bond acceptor means an atom capable of forming a hydrogen bond with a hydrogen atom contained in a water molecule. The number of hydrogen bond acceptors may be determined using the molecular simulations described above for _x2 .

When the polymer P is formed from multiple types of monomers M, _x7 can be identified by the following method. First, the number of hydrogen bond acceptors is specified for each of a plurality of types of monomers M. A weighted average is performed on the number of hydrogen bond acceptors identified, weighted by the molar proportion of each monomer M. The weighted average obtained can be taken as _x7 . In this embodiment, the value of _x7 is not particularly limited, and is, for example, 2.0 to 6.0.

The value of y calculated by the formula (1) is preferably 3.00 or less, more preferably 2.30 or less, from the viewpoint of sufficiently suppressing the transmission of iodine contained in the polarizer 1 to the outside. Yes, it may be 2.00 or less, or it may be 1.00 or less. However, the smaller the value of y, the higher the viscosity of the monomer M and the solution containing the monomer M, which tends to make it more difficult to produce the resin layer 2 . From the viewpoint that the resin layer 2 can be easily produced, the value of y is, for example, −2.00 or more, may be 0 or more, and may be 1.00 or more, or 2.00 or more in some cases. may be

The value of y calculated by the formula (1) is an index related to the monomer M for forming the polymer P contained in the resin layer 2. However, according to the studies of the present inventors, the value of y is also useful as an index for selecting the resin layer 2 suitable for suppressing the transmission of iodine contained in the polarizer 1 to the outside.

[Polarizer]
The polarizer 1 is not particularly limited as long as it contains iodine. One obtained by adsorbing iodine and uniaxially stretching is mentioned. The polarizer 1 is preferably composed of a polyvinyl alcohol film and iodine. The polarizer 1 contains polyvinyl alcohol as a main component, for example. In the present specification, the “main component” means the material contained in the polarizer 1 in the largest amount on a weight basis.

The thickness of the polarizer 1 is not particularly limited. Especially 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, optionally 1 μm or more and less than 7 μm, particularly 4 to 6 μm. In this specification, the polarizer 1 having a thickness of 10 μm or less is sometimes referred to as a thin polarizer. Thin polarizers tend to have less unevenness in thickness and have excellent visibility. Furthermore, thin polarizers have the advantage of being suppressed in dimensional change and excellent in durability. According to the thin polarizer, the polarizing film 10 can be thinned. When the polarizer 1 is a thin polarizer, it is necessary to adjust the concentration of iodine in the polarizer 1 to be high so that the polarizing film 10 has a practically sufficient degree of polarization. In the polarizing film 10 of the present embodiment, even when the thickness of the polarizer 1 is small and the concentration of iodine in the polarizer 1 is high, the transmission of iodine from the polarizer 1 to the outside is sufficiently suppressed. can be done.

The polarizer 1 can be produced by, for example, 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 its original length. If necessary, the hydrophilic polymer film may be immersed in an aqueous solution containing boric acid, potassium iodide, or the like. Furthermore, 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 antiblocking agents adhering to the surface can be removed. When the hydrophilic polymer film is washed with water, the hydrophilic polymer film swells, which has the effect of suppressing uneven dyeing. Stretching of the hydrophilic polymer film may be performed after dyeing with iodine, may be performed while dyeing, or may be performed 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.

As a thin polarizer, typically, JP-A-51-069644, JP-A-2000-338329, WO 2010/100917, JP-A-2014-59328, JP-A-2012-73563 and the like. These thin polarizers are produced by a manufacturing method including a step of stretching a laminate including a polyvinyl alcohol-based resin (PVA-based resin) layer and a stretching resin substrate, and a step of dyeing the obtained stretched film. can. In this production method, since the PVA-based resin layer is supported by the resin substrate for stretching, defects such as breakage due to stretching are less likely to occur.

From the viewpoint that the thin polarizer can be stretched at a high magnification and the polarizing performance can be improved, it is preferable that the thin polarizer is manufactured by a manufacturing method including a stretching step in an aqueous boric acid solution among the above manufacturing methods. In particular, it is preferably produced by a manufacturing method including a step of performing auxiliary stretching in the air 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 WO 2010/100917, JP 2014-59328, JP 2012-73563, and the like. A manufacturing method including a step of performing aerial stretching is disclosed in JP-A-2014-59328, JP-A-2012-73563, and the like.

[Resin layer]
As described above, the resin layer 2 contains a polymer P having at least one selected from the group consisting of the structural unit U1 derived from the compound A1 containing an epoxy group and the structural unit U2 derived from the compound A2 containing an oxetane group. include. Compounds A1 and A2 can be used as monomers M for forming polymers P.

Compound A1 may be a monofunctional epoxy compound containing one epoxy group, or may be a polyfunctional epoxy compound containing two or more epoxy groups. The number of epoxy groups contained in the polyfunctional epoxy compound is not particularly limited, and is, for example, 2 or more, preferably 2-6, more preferably 2-4.

The compound A1 may not contain a ring structure R other than an epoxy group, but preferably contains it. The number of ring structures R contained in compound A1 is, for example, 1 or more, preferably 1-10, and may be 1-6. In the compound A1, multiple ring structures R may be condensed with each other. In the compound A1, the epoxy ring and the ring structure R may be condensed. As used herein, "fused" refers to the state in which two adjacent ring structures share two or more carbon atoms with a covalent bond formed between those carbon atoms. means.

Compound A1 preferably contains, as ring structure R, at least one selected from the group consisting of an aliphatic ring and an aromatic ring. Aliphatic rings are ring structures that have no aromatic character and are composed only of carbon atoms. The number of carbon atoms in the aliphatic ring is not particularly limited, and is, for example, 5-10. Specific examples of the aliphatic ring include cyclopentane ring, cyclohexane ring, cycloheptane ring and the like. Two aliphatic rings may be fused together to form a norbornane ring and the like. An aromatic ring is a ring structure having aromatic character. The aromatic ring may consist only of carbon atoms. Aromatic rings are typically benzene rings.

The ring structure R is not limited to the above-mentioned aliphatic ring and aromatic ring. The ring structure R may be a heterocyclic ring containing a heteroatom such as a nitrogen atom or an oxygen atom. As an example, compound A1 may contain an oxetane ring as a heterocyclic ring, but preferably does not.

The compound A1 may further contain functional groups other than the epoxy group. Other functional groups include, for example, ether groups, ester groups, and the like. Compound A1 may further contain a polar group containing a bond between a hydrogen atom and a heteroatom as another functional group, but preferably does not contain a polar group. Polar groups include, for example, hydroxyl groups, carboxyl groups, primary amine groups and secondary amine groups.

The compound A1 may be an epoxy monomer or an epoxy prepolymer (epoxy resin). Compound A1 is preferably an epoxy monomer. The molecular weight of the epoxy monomer is not particularly limited, and is, for example, less than 1000, preferably 800 or less, and may be 500 or less. The weight average molecular weight of the epoxy prepolymer is not particularly limited, and is, for example, 1,000 to 50,000.

Specific examples of the compound A1 having an aromatic ring include glycidyl ether compounds (e.g., bisphenol-type epoxy resins) having a structure derived from bisphenols such as bisphenol A, bisphenol F, and bisphenol S; Glycidyl ether compounds having structures derived from other phenols such as hydroxybenzophenone, polyvinylphenol, t-butylphenol; 9,9-bis{4-[2-(oxiran-2-ylmethoxy)ethoxy]phenyl}-9H- Glycidyl ether compounds having a fluorene skeleton such as fluorene, 3′,6′-bis(oxiran-2-ylmethoxy)spiro[fluorene-9,9′-xanthene]; phenol novolak epoxy resin, cresol novolac epoxy resin and hydroxybenzaldehyde phenol A novolac type epoxy resin such as a novolac epoxy resin can be used.

Specific examples of compound A1 having an aliphatic ring include vinylcyclohexene dioxide, 3′,4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, limonene dioxide, bis(3,4-epoxycyclohexylmethyl ) Epoxy compounds having a cyclohexane skeleton such as adipate; Epoxy compounds having a condensed ring skeleton such as ',2':6,7]naphth[2,3-b]oxirane; and dicyclopentadiene type epoxy resins.

Specific examples of the compound A1 containing no ring structure R other than an epoxy group include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, Glycidyl ether compounds such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and the like.

The compounds A1 exemplified above may be used singly or in combination of two or more.

Compound A2 may be a monofunctional oxetane compound containing one oxetane group, or may be a polyfunctional oxetane compound containing two or more oxetane groups. The number of oxetane groups contained in the polyfunctional oxetane compound is not particularly limited, and is, for example, 2 or more, preferably 2-6, more preferably 2-4. Compound A2 tends to accelerate the reaction for synthesizing polymer P.

Compound A2 may or may not further contain a ring structure other than an oxetane group. Examples of ring structures other than the oxetane group include those described above for compound A1. Compound A2, for example, does not contain an epoxy group as a ring structure other than an oxetane group.

The compound A2 may further contain functional groups other than the oxetane group. Other functional groups include, for example, ether groups, ester groups, and the like. Compound A2 may further contain a polar group as another functional group, but preferably does not contain a polar group.

The compound A2 may be an oxetane monomer or an oxetane prepolymer (oxetane resin). Compound A2 is preferably an oxetane monomer. The molecular weight of the oxetane monomer is not particularly limited, and is, for example, less than 1000, preferably 800 or less, and may be 500 or less. The weight average molecular weight of the oxetane prepolymer is not particularly limited, and is, for example, 1,000 to 50,000.

Specific examples of compound A2 include oxetanes such as 3-ethyl-3-hydroxymethyloxetane, bis[(3-ethyl-3-oxetanyl)methyl]ether, and 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, 4,4'-(3 oxetane compounds containing a benzene ring such as -ethyloxetan-3-ylmethyloxymethyl)biphenyl; The compounds A2 exemplified above may be used singly or in combination of two or more.

In the polymer P, the content of the structural unit U1 derived from the compound A1 is not particularly limited. , 70% by weight or more. The polymer P may be substantially composed only of the structural unit U1. As used herein, "consisting essentially of" means excluding other structural units that alter the essential characteristics of the structural unit referred to, for example, 95% by weight or more, or even 99% by weight. It means that the weight % or more is composed of the structural unit. A preferred range for the content of the structural unit U1 is, for example, 50% by weight to 90% by weight.

In the polymer P, the content of the structural unit U2 derived from the compound A2 is not particularly limited, and may be, for example, 5 wt% or more, may be 10 wt% or more, or may be 20 wt% or more. , 30% by weight or more, 40% by weight or more, or 50% by weight or more. The polymer P may consist substantially only of structural units U2. A preferred range for the content of the structural unit U2 is, for example, 10% to 50% by weight.

The polymer P preferably contains both the structural unit U1 and the structural unit U2. In the polymer P, the total value of the content of the structural unit U1 and the content of the structural unit U2 is, for example, 50% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more. more preferably 90% by weight or more, particularly preferably 95% by weight or more, particularly preferably 99% by weight or more.

The polymer P may further contain structural units derived from cationic polymerizable monomers other than compounds A1 and A2. Furthermore, the polymer P may contain a structural unit derived from a radically polymerizable monomer.

Other cationically polymerizable monomers include, for example, vinyl ether 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; - polyfunctional vinyl ethers such as divinyl ether, triethylene glycol divinyl ether and dipropylene glycol divinyl ether;

Examples of radically polymerizable monomers include (meth)acrylic acid esters and styrene compounds. As used herein, "(meth)acrylic acid" means acrylic acid and/or methacrylic acid.

(Meth)acrylic acid esters, for example, dicyclopentanyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, lauryl (meth)acrylate, 5-(meth)acryloxy-2,6-norbornane carboractone, 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-anthracenemethyl (meth)acrylate, 9-anthracenemethyl (meth)acrylate and other monofunctional (meth)acrylates; Kandi (meth)acrylate, 1,3-adamantanediol di(meth)acrylate, 1,3,5-adamantanetriol-1,5-di(meth)acrylate, 9,9-bis[4-(2-(meth) ) Acryloyloxyethoxy) phenyl] bifunctional (meth) acrylic acid ester such as fluorene; trifunctional (meth)acrylate; tetrafunctional (meth)acrylate such as pentaerythritol tetra(meth)acrylate; and hexafunctional (meth)acrylate such as dipentaerythritol hexa(meth)acrylate.

Examples of styrene compounds include styrene, α-methylstyrene, vinylbenzyl chloride, butoxystyrene, and vinylpyridine.

The polymer P preferably contains structural units derived from polyfunctional monomers. Examples of polyfunctional monomers include the aforementioned polyfunctional epoxy compounds, polyfunctional oxetane compounds, polyfunctional (meth)acrylic acid esters, and polyfunctional vinyl ether compounds. 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. or more. The upper limit of the content of structural units 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. 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 structural units 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, and still more preferably 5% by weight or less, Particularly preferably, it is 2% by weight or less.

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 still more preferably 95% by weight or more. The resin layer 2 preferably consists essentially of the polymer P only.

However, the resin layer 2 may contain components other than the polymer P. Other components include acid generators, decomposition products of acid generators, antistatic agents, antioxidants, inorganic particles, leveling agents, and the like. The resin layer 2 contains, for example, an acid generator and/or a decomposition product of the acid generator as other components. The acid generator is typically a photoacid generator that functions as a polymerization initiator for compound A1 and compound A2.

Examples of photoacid generators include compounds represented by the following formula (i).
L ⁺ X ⁻ (i)

In formula (i), L ⁺ is an onium cation. Onium cations include sulfonium cations, sulfoxonium cations, phosphonium cations, pyridinium cations, quinolinium cations, isoquinolinium cations, benzoxazolium cations, benzothiazolium cations, furryiodonium cations, thienyliodonium cations, Examples include diaryliodonium cations, preferably sulfonium cations.

X ⁻ is a counter anion. Examples of counter anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate anions, SCN ⁻ and the like, preferably PF ₆ ^{− .} be.

Specific examples of the photoacid generator include "Cyracure UVI-6992", "Cyracure UVI-6974" (manufactured by Dow Chemical Japan Co., Ltd.), "ADEKA OPTOMER SP150", "ADEKA OPTOMER SP152", "ADEKA OPTOMER SP170", "ADEKA OPTOMER SP172" (manufactured by ADEKA Corporation), "IRGACURE250" (manufactured by Ciba Specialty Chemicals), "CI-5102", "CI-2855" (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" (manufactured by Sanshin Chemical Co., Ltd.) , “CPI-100P”, “CPI-100A” (manufactured by San-Apro Co., Ltd.), “WPI-069”, “WPI-113”, “WPI-116”, “WPI-041”, “WPI-044” , “WPI-054”, “WPI-055”, “WPAG-281”, “WPAG-567”, and “WPAG-596” (manufactured by Wako Pure Chemical Industries, Ltd.).

The thickness of the resin layer 2 is not particularly limited, and is, for example, 10 μm or less, preferably 5 μm or less, more preferably less than 3 μm, and even more preferably less than 2.5 μm. There is a tendency that the thinner the resin layer 2 is, the less the acid generator used for forming the resin layer 2 can be used. When the amount of the acid generator used is small, even if the resin layer 2 is in direct contact with the polarizer 1, the acid generated from the acid generator is less likely to move from the resin layer 2 to the polarizer 1, thereby preventing deterioration of the polarizer 1. tend to be suppressed. From the viewpoint of sufficiently suppressing 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.

As described above, 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 bonding the resin layer 2 to the polarizer 1 include those exemplified for the adhesive layer 3 to be described later. The easy-adhesion layer can be formed of, for example, a resin containing a polymer having a polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, silicone system, polyamide skeleton, polyimide skeleton, polyvinyl alcohol skeleton, or the like. One type or two or more types of polymers may be contained in the resin. The easy-adhesion layer may contain an additive. Additives include tackifiers, ultraviolet absorbers, antioxidants, stabilizers such as heat-resistant stabilizers, and the like. The thickness of the easy-adhesion layer is not particularly limited, but is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, still more 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. Materials for the adhesive are not particularly limited, and known materials can be used. Examples of adhesives contained in the adhesive layer 3 include water-based adhesives and active energy ray-curable adhesives. As the active energy ray-curable adhesive, for example, those disclosed in JP-A-2019-147865, JP-A-2016-177248, etc. can be used.

The thickness of the adhesive layer 3 is not particularly limited. 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 be lowered. When the thickness of the adhesive layer 3 is too large, peeling may occur in the adhesive layer 3 when stress is applied to the cross section of the polarizing film 10 . That is, in the polarizing film 10, peeling failure due to impact may occur.

[Protective film]
As the protective film 4, a film having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is preferable. Protective film 4 is typically a transparent protective film. Examples of materials for the 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; Styrene-based polymers such as styrene copolymers (AS resins); polycarbonate-based polymers; olefin-based polymers such as polyethylene, polypropylene, and ethylene/propylene copolymers; cyclic olefin-based polymers such as polynorbornene; vinyl chloride-based polymers; Amide-based polymers such as aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; arylate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; and mixtures of these polymers.

The protective film 4 preferably contains a polymer that functions as a thermoplastic resin among the above-described polymers. The content of the thermoplastic resin in the protective film 4 is preferably 50 wt% to 100 wt%, more preferably 50 wt% to 99 wt%, still more preferably 60 wt% to 98 wt%, Especially preferred is 70% to 97% by weight. If the content of the thermoplastic resin in the protective film 4 is less than 50% by weight, the functions inherent in the thermoplastic resin, such as high transparency, may not be sufficiently exhibited. The protective film 4 preferably contains triacetyl cellulose (TAC) as a main component among the polymers described above. The protective film 4 containing TAC tends to have high breaking strength and excellent crack resistance. This protective film 4 also tends to be low in cost.

The protective film 4 may be a polymer film described in JP-A-2001-343529, International Publication No. 01/37007, and the like. Materials for this polymer film include, for example, thermoplastic resins having substituted and/or unsubstituted imide groups in side chains, and thermoplastic resins having substituted and/or unsubstituted phenyl groups and nitrile groups in side chains. A resin composition containing A specific example of the polymer film is a film formed from a resin composition containing an alternating copolymer 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 retardation and a small photoelastic coefficient, problems such as unevenness due to distortion of the polarizing film 10 can be eliminated. Furthermore, since this film has a low moisture permeability, it has excellent durability in a humid environment.

The protective film 4 may contain one or more additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

The moisture permeability of the protective film 4 is not particularly limited, and may exceed 150 g/(m ² ·day), may be 300 g/(m ² ·day) or more, and may be 500 g/(m ² ·day). ) or more. In the polarizing film 10 of the present embodiment, even when the protective film 4 has high moisture permeability, the resin layer 2 can sufficiently suppress the permeation of iodine contained in the polarizer 1 to the outside. The upper limit of the moisture permeability of the protective film 4 is not particularly limited, and is, for example, 5000 g/(m ² ·day), and may be 1000 g/(m ² ·day). The protective film 4 containing TAC tends to have high moisture permeability.

The moisture permeability of the protective film 4 can be measured by the following method according to the Japanese Industrial Standard (JIS) Z0208 moisture permeability test (cup method). First, the protective film 4 is cut into a diameter of 60 mm to prepare a measurement sample. Next, a measurement sample is set in a moisture-permeable cup in which about 15 g of calcium chloride is placed. This moisture permeable cup is placed in a constant temperature machine set at a temperature of 40° C. and a humidity of 92% RH, and left for 24 hours to conduct a moisture permeability test. By measuring the amount of increase in the weight of calcium chloride before and after the test, the moisture permeability of the protective film 4 can be specified.

The moisture permeability of the protective film 4 may be 150 g/(m ² ·day) or less. In this case, it is possible to suppress the intrusion of moisture in the air into the polarizing film 10 and suppress the change in the moisture content of the polarizing film 10 . As a result, the polarizing film 10 can be prevented from curling or undergoing dimensional changes during storage. Examples of materials for forming the protective film 4 with low moisture permeability include polyester-based polymers, polycarbonate-based polymers, arylate-based polymers, amide-based polymers, olefin-based polymers, cyclic olefin-based polymers, (meth)acrylic-based polymers, and these. A mixture of

Although the thickness of the protective film 4 is not particularly limited, it 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 and handleability. The thickness of the protective film 4 may be less than 40 μm.

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

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

The adhesive layer 5 may be a laminate of multiple 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, more preferably 1 to 100 μm. The thickness of the adhesive layer 5 may be 50 μm or less.

The pressure-sensitive adhesive layer 5 may be attached to the separator before the polarizing film 10 is attached to the image display panel. The separator can prevent contamination of the pressure-sensitive adhesive layer 5 . As the separator, for example, for thin films such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils and laminates thereof, silicone-based, long-chain alkyl-based, fluorine-based , Molybdenum sulfide, etc. can be used.

[Other members]
The polarizing film 10 may further include members other than the members described above. The polarizing film 10 may further include, for example, a transparent substrate positioned closer to the viewer than the resin layer 2 is. A transparent substrate may be positioned on the outermost side of the polarizing film 10 . The transparent substrate is made of glass or polymer, for example. 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 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, those described above for the pressure-sensitive 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 reflector, anti-transmission plate, retardation film, viewing angle compensation film, brightness enhancement film, and the like. Retardation films include, for example, half-wave plates, quarter-wave plates, and the like. In the polarizing film 10, the retardation film may be arranged closer to the image display panel than the polarizer 1 (for example, between the adhesive layer 5 and the protective film 4), and closer to the viewer than the polarizer 1. may be placed.

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

[Method for producing polarizing film]
The method for producing the polarizing film 10 includes, for example, a step of obtaining a polymer P by polymerizing a monomer M whose y value calculated by the above formula (1) is less than 4.00. Specifically, the polarizing film 10 can be manufactured by the following method. First, the polarizer 1 and the protective film 4 are pasted together with the adhesive layer 3 interposed therebetween. Next, a coating liquid containing the monomer M and a polymerization initiator is prepared. The polymerization initiator is typically the acid generator mentioned above for resin layer 2 .

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 0.1 to 5% by weight. %.

Next, the coating liquid is applied onto the polarizer 1. Thereby, 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. Polymerization of the monomer M can be carried out by a known method. For example, when a photoacid generator is used as the polymerization initiator, the monomer M can be polymerized by irradiating the coating film with an active energy ray. Active energy rays include, for example, visible light and ultraviolet rays. In this 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 bonding the adhesive layer 5 to the protective film 4 .

The resin layer 2 may be produced by the following method. First, the monomer M is polymerized to obtain the polymer P. The obtained polymer P is added to a solvent to prepare a coating liquid. Examples of the solvent include organic solvents 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, transmission of iodine contained in the polarizer 1 to the outside is sufficiently suppressed in a hot and humid environment. That is, the concentration of iodine in the polarizer 1 hardly changes in a hot and humid environment. A change in the concentration of iodine in the polarizer 1 can be read, for example, from a change in the single transmittance of the polarizing film 10 . As an example, when the polarizing film 10 is placed in an atmosphere of 65 ° C. and 90% RH for 8 hours in a state where the polarizing film 10 is attached to non-alkali glass via the adhesive layer 5, the single transmission of the polarizing film 10 The rate change ΔY1 is, for example, 4 or less, preferably 3 or less, more preferably 2 or less, still more preferably 1.85 or less, particularly preferably 1.5 or less, and particularly preferably 1 or less.

Specifically, the change ΔY1 in single transmittance can be measured by the following method. First, the single transmittance Ts1 of the laminate obtained by bonding the polarizing film 10 to the non-alkali glass via the adhesive layer 5 is measured. Next, this laminate is placed in an atmosphere of 65° C. and 90% RH for 8 hours. The single transmittance Ts2 of the laminate after being placed in this atmosphere is measured. A value obtained by subtracting the single transmittance Ts1 from the single transmittance Ts2 is regarded as the single transmittance change ΔY1. The single transmittance of the laminated body is the Y value corrected for visual sensitivity using a 2-degree field of view (C light source) of JIS Z8701-1999. Single transmittance can be measured using a commercially available spectrophotometer such as DOT-3 manufactured by Murakami Color Research Laboratory. The measurement wavelength of single transmittance is 380 to 700 nm (every 10 nm). Alkali-free glass is glass that does not substantially contain alkali components (alkali metal oxides). Specifically, the weight ratio of alkali components in the glass is, for example, 1000 ppm or less, and further 500 ppm or less. The alkali-free 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. Single transmittance Ts2 is not particularly limited, and is, for example, 42% to 48%, preferably 47% or less, and more preferably 46% or less.

Furthermore, when the polarizing film 10 is placed in an atmosphere of 65 ° C. and 90% RH for 24 hours with the polarizing film 10 attached to the non-alkali glass via the adhesive layer 5, the single transmittance of the polarizing film 10 is, for example, 20 or less, preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, and particularly preferably 2 or less.

The change ΔY2 in the transmittance of the single unit was obtained by placing the laminate obtained by bonding the polarizing film 10 to the non-alkali glass via the adhesive layer 5 in an atmosphere of 65° C. and 90% RH for 24 hours. The transmittance change ΔY1 can be measured by the same method as described above.

(Modification of polarizing film)
FIG. 2 is a schematic cross-sectional view of a polarizing film 11 according to a modification. As shown in FIG. 2, in the polarizing film 11 of this modified example, the protective film 4 is positioned closer to the viewer than the resin layer 2, and the protective film 4, the resin layer 2, and the polarizer 1 are arranged in the stacking direction. They are in order. The polarizing film 11 does not have the adhesive layer 3 . Except for the above, the structure of the polarizing film 11 is the same as that of the polarizing film 10 . Therefore, elements common to the polarizing film 10 and the polarizing film 11 are denoted by the same reference numerals, and description thereof may be omitted. That is, the descriptions of the following embodiments are mutually applicable unless technically inconsistent. Each of the following embodiments may be combined with each other as long as they are not technically inconsistent.

The resin layer 2 is in direct contact with each of the polarizer 1 and the protective film 4. A polarizer 1 and a protective film 4 are bonded together with a resin layer 2 interposed therebetween. However, between the resin layer 2 and the polarizer 1 or between the resin layer 2 and the protective film 4, other layers such as an adhesive layer and an easy-adhesion layer may be arranged. These members may be bonded together via an adhesive layer or an easy-adhesion layer. Examples of the adhesive layer and the easy-adhesion layer include those described above for the polarizing film 10 .

The polarizing film 11 may further include a hard coat layer positioned closer to the viewer than the protective film 4 is. A hard coat layer may be positioned on the outermost side of the polarizing film 11 . However, when the polarizing film 11 includes the transparent substrate described above, the hard coat layer may be positioned between the protective film 4 and the transparent substrate.

In the polarizing film 11, both the protective film 4 and the resin layer 2 are positioned closer to the viewer than the polarizer 1 is. This polarizing film 11 tends to further suppress transmission of iodine contained in the polarizer 1 to the outside in a hot and humid environment. As an example, when the polarizing film 11 is attached to non-alkali glass via the adhesive layer 5 and placed in an atmosphere of 85 ° C. and 85% RH for 120 hours, the single transmission of the polarizing film 11 The rate change ΔY3 is, for example, 2 or less, preferably 1.6 or less, more preferably 1.5 or less, still more preferably 1.3 or less, and may be 1.2 or less. , 1 or less.

Specifically, the change ΔY3 in single transmittance can be measured by the following method. First, the single transmittance Ts3 of the laminate obtained by bonding the polarizing film 11 to the non-alkali glass via the adhesive layer 5 is measured. Next, this laminate is placed in an atmosphere of 85° C. and 85% RH for 120 hours. The single transmittance Ts4 of the laminate after being placed in this atmosphere is measured. A value obtained by subtracting the single transmittance Ts3 from the single transmittance Ts4 is regarded as the single transmittance change ΔY3.

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. Single transmittance Ts4 is not particularly limited, and is, for example, 42% to 48%, preferably 47% or less, and more preferably 46% or less.

Furthermore, when the polarizing film 11 is placed in an atmosphere of 85 ° C. and 85% RH for 240 hours in a state where the polarizing film 11 is attached to non-alkali glass through the adhesive layer 5, the transmittance of the polarizing film 11 alone The change ΔY4 is, for example, 1.6 or less, preferably 1.5 or less, more preferably 1.4 or less, still more preferably 1.3 or less, and particularly preferably 1.2 or less. be.

The change ΔY4 in the transmittance of the single unit was obtained by placing the laminate obtained by bonding the polarizing film 11 to the non-alkali glass via the adhesive layer 5 in an atmosphere of 85° C. and 85% RH for 240 hours. The transmittance change ΔY3 can be measured by the same method as described above.

(Another modification of the polarizing film)
In the polarizing film 10 , the resin layer 2 may be located closer to the image display panel (to be described later) than the polarizer 1 is. As shown in FIG. 3 , in the polarizing film 12 according to this modified example, the resin layer 2 is located closer to the image display panel than the polarizer 1 is. The structure of the polarizing film 12 is the same as that of the polarizing film 10 except for the position of the resin layer 2 .

The resin layer 2 is positioned, for example, between the polarizer 1 and the adhesive layer 3 and is in direct contact with the polarizer 1 and the adhesive layer 3 respectively. However, between the resin layer 2 and the polarizer 1, another layer such as an adhesive layer or an easy-adhesion layer may be arranged. 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-adhesion layer for bonding the resin layer 2 to the polarizer 1 include those described above for the polarizing film 10 . When the resin layer 2 is positioned closer to the image display panel than the polarizer 1, the iodine contained in the polarizer 1 moves to the adhesive layer 5 in a hot and humid environment, and passes through the adhesive layer 5 to the polarizing film 12. It is possible to suppress permeation to the outside.

(Still another modification of the polarizing film)
The polarizing film 10 may further include members other than the members described above. As shown in FIG. 4, the polarizing film 13 according to this modified example further has a protective film (second protective film) 6 in addition to the protective film (first protective film) 4 described above. The structure of the polarizing film 13 is the same as that of the polarizing film 10 except for the second protective film 6 .

The second protective film 6 is positioned closer to the viewer than the polarizer 1 is. Polarizer 1 is positioned, for example, between first protective film 4 and second protective film 6 . The second protective film 6 is, for example, located on the viewing side of the resin layer 2 and on the outermost side of the polarizing film 13 . However, when the polarizing film 13 includes the transparent substrate described above, the second protective film 6 may be positioned between the resin layer 2 and the transparent substrate. The second protective film 6 is in direct contact with the resin layer 2, for example. However, the second protective film 6 may be attached to the resin layer 2 via other layers such as an adhesive layer and a hard coat layer. Examples of the adhesive layer for bonding the second protective film 6 to the resin layer 2 include those described above for the adhesive layer 3 .

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

(Still another modification of the polarizing film)
The polarizing film 10 may have two or more resin layers 2 . As shown in FIG. 5, the polarizing film 14 according to this modification includes two resin layers 2a and 2b. The structure of the polarizing film 14 is the same as that of the polarizing film 10 except for the resin layer 2b.

In the polarizing film 14, the polarizer 1 is positioned between the two resin layers 2a and 2b. Specifically, the resin layer 2b is positioned closer to the image display panel 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, the polarizing film 14 tends to further suppress transmission of iodine contained in the polarizer 1 to the outside.

The resin layer 2b may be in direct contact with the polarizer 1. However, between the resin layer 2b and the polarizer 1, another layer such as an adhesive layer or an easy-adhesion layer may be arranged. 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-adhesion layer for bonding 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. 6, the image display device 100 of this embodiment includes a polarizing film 10 and an image display panel 20. As shown in FIG. In the image display device 100, a polarizing film 11, 12, 13 or 14 can also be used instead of the polarizing film 10. FIG. In the image display device 100, the polarizing film 10 is attached to the image display panel 20 via the adhesive layer 5, for example. Examples of the image display panel 20 include an organic EL display panel and a liquid crystal display panel, and the organic EL display panel is preferable.

The image display device 100 further includes, for example, an illumination 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.

The present invention will be described in more detail below with reference to examples. The invention is not limited to the examples shown below.

[Example 1]
(Preparation of polarizing film A)
<Thin polarizer>
First, a laminate was prepared by forming a PVA layer having a thickness of 9 μm on an amorphous polyethylene terephthalate (PET) substrate. A stretched laminate was produced by subjecting this laminate to auxiliary stretching in the air at a stretching temperature of 130°C. Next, the stretched laminate was dyed with iodine to obtain a colored laminate. Further, the colored laminate was stretched in an aqueous boric acid solution at a stretching temperature of 65° C. to obtain a laminate a in which the amorphous PET substrate and the PVA layer were integrally stretched. In the laminate a, the total draw ratio was 5.94 times and the thickness of the PVA layer was 5 µm. The PVA molecules of the PVA layer formed on the amorphous PET substrate were highly oriented by the above two-stage stretching. Furthermore, the iodine adsorbed by staining was highly oriented in one direction as a polyiodine ion complex. The PVA layer included in laminate a functioned as a thin polarizer.

<Transparent protective film>
First, a resin (imidized MS resin) composed of an imidized methyl methacrylate-styrene copolymer was produced 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, manufactured by Adeka Co., Ltd.) are mixed at 220° C. to obtain resin pellets. was made. The obtained resin pellets were dried in an environment of 100.5 kPa and 100° C. for 12 hours. Next, using a single-screw extruder, a film having a thickness of 160 μm was produced by extruding resin pellets from a T-die at a die temperature of 270°C. Further, this film was stretched in the transport direction under an atmosphere of 150° C. to adjust the thickness to 80 μm. Next, a transparent protective film I having a thickness of 40 μm was obtained by applying an easy-adhesive agent containing a water-based urethane resin to the film and stretching the film in an atmosphere of 150° C. in a direction perpendicular to the transport direction. The moisture permeability of this transparent protective film I was 58 g/(m ² ·day) under the conditions of 40° C. and 92% RH.

<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 Toagosei Co., Ltd., trade name: ARONIX M-5700), 12 parts by weight 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 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, trade name: OMNIRAD 907) and 2 parts by weight of 2,4-diethylthioxanthone (manufactured by Nippon Kayaku, trade name: KAYACURE DETX-S) are mixed and stirred for 3 hours. Thus, an active energy ray-curable adhesive composition was obtained.

<Laminate containing transparent protective film, adhesive layer and thin polarizer>
Using an MCD coater manufactured by Fuji Machine Co., Ltd. (cell shape: honeycomb, gravure roll line number: 1000 lines/inch, rotation speed: 140%/line speed), the active energy ray-curable adhesive composition was coated with a transparent protective film I. was coated on the bonding surface of The thickness of the resulting coating film was 0.7 μm. Next, using a roll machine, the transparent protective film I and the laminate a containing the PVA layer were pasted together. At this time, the coating film and the PVA layer were brought into contact with each other. The line speed of the roll mill was 25 m/min. Next, the obtained laminate was irradiated with an active energy ray from the transparent protective film side. As the active energy ray, visible light emitted from a visible light irradiation device (Light HAMMER10 manufactured by Fusion UV Systems) was used. The light source of the visible light irradiation device was a gallium-filled metal halide lamp. A V-bulb was used as a bulb in the visible light irradiation device. The peak illuminance of light emitted from the visible light irradiation device was 1600 mW/cm ² . In the wavelength range of 380 nm to 440 nm, the cumulative irradiation amount of light emitted from the visible light irradiation device was 1000 mJ/cm ² . The illuminance of light emitted from the visible light irradiation device was measured using a Sola-Check system manufactured by Solatell. By irradiating the laminate with an active energy ray, 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 b containing the transparent protective film I, the adhesive layer and the thin polarizer.

<Resin layer>
First, 60 parts by weight of 3′,6′-bis(oxiran-2-ylmethoxy)spiro[fluorene-9,9′-xanthene] (manufactured by Taoka Chemical Co., Ltd., trade name: TBIS-RXG), 20 parts by weight of Bis [(3-ethyl-3-oxetanyl) methyl] ether (manufactured by Toagosei Co., Ltd., trade name: OXT-221), 20 parts by weight of 4-t-butylphenyl glycidyl ether (manufactured by Nagase ChemteX Corporation, trade name: Denacol EX-146) and 10 parts by weight of a photoacid generator (manufactured by San-Apro Co., Ltd., trade name: CPI-100P) were mixed and stirred at 25° C. for 1 hour to prepare a coating solution.

Next, the amorphous PET substrate adjacent to the PVA layer was removed from the laminate b, and the exposed surface of the PVA layer was subjected to corona treatment. Next, using an MCD coater manufactured by Fuji Machine Co., Ltd. (cell shape: honeycomb, number of gravure roll lines: 250 lines/inch, rotation speed: 160%/line speed), the above coating solution was applied onto the exposed PVA layer. was coated. The thickness of the resulting coating film was 2.0 μm. Next, a COP film (trade name: ZF14, thickness: 25 μm, manufactured by Nippon Zeon Co., Ltd.) was bonded to the PVA layer using a roll machine. At this time, the coating film and the COP film were brought into contact with each other. The line speed of the roll mill was 25 m/min. Next, the obtained laminate was irradiated with an active energy ray from the COP film side. As the active energy ray, ultraviolet rays emitted from an irradiation device (Light HAMMER10 manufactured by Fusion UV Systems) were used. In the irradiation device, an H bulb was used as a bulb. The peak illuminance of light emitted from the irradiation device was 200 mW/cm ² . In the wavelength range of 330 nm to 390 nm, the cumulative irradiation amount of light emitted from the irradiation device was 600 mJ/cm ² . The illuminance and cumulative irradiation amount of the emitted light from the irradiation device were measured using a UV radiometer POWER PUCK II manufactured by EIT. 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 monomer. Next, this laminate was dried with hot air at 70° C. for 3 minutes, and then allowed to stand at 25° C. for 24 hours. Thereby, a resin layer was formed. By peeling the COP film from this laminate, a laminate c including the transparent protective film I, the adhesive layer, the thin polarizer and the resin layer was obtained.

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

(Preparation of polarizing film B)
First, the bonding surface of the transparent protective film I was subjected to corona treatment. Next, using an MCD coater manufactured by Fuji Machinery Co., Ltd. (cell shape: honeycomb, number of gravure roll lines: 250 lines/inch, rotation speed: 160%/line speed), the above-mentioned coating was applied to the bonding surface of the transparent protective film I. A coating liquid was applied. The thickness of the resulting coating film was 2.0 μm. Next, using a roll machine, the transparent protective film I and the laminate a containing the PVA layer were pasted together. At this time, the coating film and the PVA layer were brought into contact with each other. The line speed of the roll mill was 25 m/min. Next, the obtained laminate was irradiated with an active energy ray from the thin polarizer side. As the active energy ray, the ultraviolet rays described above for the polarizing film A were 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 monomer. Next, this laminate was dried with hot air at 70° C. for 3 minutes, and then allowed to stand at 25° C. for 24 hours. Thereby, a resin layer was formed to obtain a laminate d including the transparent protective film I, the resin layer and the thin polarizer.

Next, the amorphous PET base material adjacent to the PVA layer was removed from the obtained laminate d, and the exposed surface of the PVA layer was subjected to corona treatment. A pressure-sensitive adhesive layer having a thickness of 20 μm was attached to this surface. The adhesive layer was composed of an acrylic adhesive. As a result, a polarizing film B comprising a transparent protective film I, a resin layer, a polarizer and an adhesive layer in this order was obtained.

(Preparation of polarizing film C)
<Transparent protective film with hard coat layer>
First, a solution (manufactured by DIC, trade name: Unidic 17-806, solid concentration: 80% by weight) was prepared by dissolving an ultraviolet curable resin monomer or oligomer containing urethane acrylate as a main component in butyl acetate. Based on 100 parts by weight of the solid content of this solution, 5 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name: IRGACURE 907), and 0.1 parts by weight of a leveling agent (manufactured by DIC, trade name: GRANDIC PC4100 ) was added. Furthermore, cyclopentanone and propylene glycol monomethyl ether were added to the solution at a weight ratio of 45:55 so that the solid content concentration in the solution was adjusted to 36% by weight. Thus, a coating liquid for forming a hard coat layer was prepared.

Next, as a transparent protective film, a triacetyl cellulose (TAC) film (trade name: TJ25UL manufactured by Fuji Film Co., Ltd., raw material: triacetyl cellulose-based polymer, thickness: 25 μm, moisture permeability: 931 g/(m ² ·day) ) was prepared. A coating liquid for forming a hard coat layer was applied onto the transparent protective film to form a coating film. The thickness of the coating film was adjusted so that the thickness of the hard coat layer after curing was 7 μm. Next, the coating film was dried at 90° C. for 1 minute, and then irradiated with ultraviolet light having an accumulated light quantity of 300 mJ/cm ² using a high-pressure mercury lamp. As a result, the coating film was cured to form a hard coat layer (HC) having a thickness of 7 μm, thereby obtaining a transparent protective film II with HC. The moisture permeability of the transparent protective film II with HC was 420 g/(m ² ·day) under the conditions of 40° C. and 92% RH.

A polarizing film C was produced in the same manner as the polarizing film B, except that a transparent protective film II with HC was used instead of the transparent protective film I. The polarizing film C had a hard coat layer, a transparent protective film (TAC film), a resin layer, a polarizer and an adhesive layer in this order.

[Example 2-11, Comparative Example 1-6]
For each of Examples 2-11 and Comparative Examples 1-6, 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 listed in Table 1. , to prepare polarizing films AC.

<y value calculated by formula (1)>
The values of x ₁ to x ₇ were specified by the method described above for the monomers contained in the coating liquids for forming the resin layers used in Examples and Comparative Examples. The dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer and the common logarithm value LogS of the solubility S (g/100 g) of the monomer in water at 25°C were calculated using HSPiP (version 5). . For the molecular simulation for calculating the dipole moment of the monomer, etc., Materials Studio (manufactured by BIOVIA, ver.8.0.0.843) and WebMO (ver.19.0.009e) were used. Furthermore, the value of y was calculated based on the formula (1) using the values of x ₁ to x ₇ .

<Change in Single Transmittance ΔY1>
For the polarizing films A of Examples and Comparative Examples, change ΔY1 in single transmittance was measured by the following method. First, the polarizing film A was attached to non-alkali glass via an adhesive layer. Single transmittance Ts1 was measured for the obtained laminate. Single transmittance Ts1 was measured using a spectral transmittance meter with an integrating sphere (Dot-3c manufactured by Murakami Color Research Laboratory). Next, this laminate was placed in an atmosphere of 65° C. and 90% RH for 8 hours. The single transmittance Ts2 of the laminate after being placed in this atmosphere was measured using the spectral transmittance measuring instrument described above. By subtracting the single transmittance Ts1 from the single transmittance Ts2, the change ΔY1 in the single transmittance was calculated.

<Change in Single Transmittance ΔY2>
The change ΔY1 in single transmittance was described above, except that the laminate obtained by bonding the polarizing film A to the non-alkali glass via the adhesive layer was placed in an atmosphere of 65° C. and 90% RH for 24 hours. The change ΔY2 in single transmittance was measured by the same method as the method.

<Change in Single Transmittance ΔY3>
For the polarizing films B and C of Examples and Comparative Examples, change ΔY3 in single transmittance was measured by the following method. First, the polarizing films B and C were attached to non-alkali glass via an adhesive layer. Single transmittance Ts3 was measured for the obtained laminate. The single transmittance Ts3 was measured using a spectral transmittance meter with an integrating sphere (Dot-3c manufactured by Murakami Color Research Laboratory). Next, this laminate was placed in an atmosphere of 85° C. and 85% RH for 120 hours. The single transmittance Ts4 of the laminate after being placed in this atmosphere was measured using the spectral transmittance measuring instrument described above. By subtracting the single transmittance Ts3 from the single transmittance Ts4, the change ΔY3 in the single transmittance was calculated.

<Change in Single Transmittance ΔY4>
Except that the laminate obtained by bonding the polarizing film B to the non-alkali glass via the adhesive layer was placed in an atmosphere of 85° C. and 85% RH for 240 hours, the change in single transmittance ΔY3 was described above. The change ΔY4 in single transmittance was measured by the same method as the method.

<Crack evaluation>
A heat shock test was performed on the polarizing films B and C of Examples and Comparative Examples by the following method. First, a pressure-sensitive adhesive layer was attached to the surface of the transparent protective film I (or the transparent protective film II with HC) of the polarizing film. Next, using a CO ₂ laser (manufactured by COMNET, product name: Laser Pro-SPIRIT), the resulting laminate was cut into the shape shown in FIG. Specifically, the measurement sample 15 was produced by cutting a part of a strip-shaped laminate of 50 mm long×150 mm wide in a V-shape from one long side of the laminate. At this time, the angle formed by the long side of the laminate before cutting and the cut surface was adjusted to 14°. In the strip-shaped laminate, the direction of the absorption axis coincided with the direction in which the short sides extend. The irradiation conditions of the CO ₂ laser were as follows.
・Irradiation conditions Wavelength: 10.6 μm
Laser output: 30W
Oscillation mode: Pulse oscillation Diameter of laser light: 70 μm
Laser irradiation surface: protective film side

Next, using the adhesive layer placed on the surface on the transparent protective film side, the measurement sample 15 was attached to non-alkali glass with a thickness of 0.5 mm. In this state, a heat shock test was performed by subjecting the measurement sample 15 to heat shocks of −40 to 80° C. 200 times. Each heat shock was performed for 30 minutes. After the heat shock test, it was confirmed whether or not a crack penetrating through the measurement sample 15 occurred in the V-shaped portion (region A in FIG. 7) of the measurement sample 15 . The above heat shock test was repeated 10 times, and the case where cracks occurred was rated as x, and the case where cracks did not occur was rated as ◯.

Table 1 below shows the evaluation results for each of the produced polarizing films.

Abbreviations in Table 1 are as follows.
TBIS-RXG: 3′,6′-bis(oxiran-2-ylmethoxy)spiro[fluorene-9,9′-xanthene] (manufactured by Taoka Chemical Co., Ltd., trade name: TBIS-RXG)
OXT-221: bis [(3-ethyl-3-oxetanyl) methyl] ether (manufactured by Toagosei Co., Ltd., trade name: OXT-221)
EX-146: 4-t-butylphenyl glycidyl ether (manufactured by Nagase ChemteX, trade name: Denacol EX-146)
jER-834: bisphenol A type epoxy resin (epoxy equivalent 230 to 270 g / eq, manufactured by Mitsubishi Chemical Corporation, trade name: jER-834)
TBIS-GG: 9,9-bis{4-[2-(oxiran-2-ylmethoxy)ethoxy]phenyl}-9H-fluorene (manufactured by Taoka Chemical Co., Ltd., trade name: TBIS-GG)
THI-DE: Bicyclononadiene diepoxide (manufactured by ENEOS, trade name: THI-DE)
ED-505: trimethylolpropane triglycidyl ether (manufactured by ADEKA, trade name: ADEKA GLYCIROL ED-505)
EP-4088S: Dicyclopentadiene type epoxy resin (manufactured by ADEKA, trade name: EP-4088S)
BATG: 2,2-bis(3-glycidyl-4-glycidyloxyphenyl)propane (manufactured by Showa Denko, trade name: Showfree BATG)
OXBP: 4,4′-(3-ethyloxetan-3-ylmethyloxymethyl)biphenyl (manufactured by Ube Industries, trade name: ETERNACOLL-OXBP)
DE-102: epoxy compound having a norbornane ring (manufactured by ENEOS, trade name: DE-102)
DE-103: Tricyclopentadiene diepoxide (manufactured by ENEOS, trade name: DE-103)
ED-523T: neopentyl glycol diglycidyl ether (manufactured by ADEKA, trade name: ADEKA GLYCIROL ED-523T)
EX-313: Glycerol polyglycidyl ether (manufactured by Nagase ChemteX, trade name: Denacol EX-313)
EX-212: 1,6-hexanediol diglycidyl ether (manufactured by Nagase ChemteX, trade name: Denacol EX-212)
EX-832: Polyethylene glycol diglycidyl ether (epoxy equivalent 284 g/eq, manufactured by Nagase ChemteX Corporation, trade name: Denacol EX-832)
EX-821: polyethylene glycol diglycidyl ether (epoxy equivalent 185 g/eq, manufactured by Nagase ChemteX Corporation, trade name: Denacol EX-821)

As can be seen from Table 1, in the polarizing films A to C of Examples in which the value of y calculated by Equation (1) is less than 4.00, the single transmission is higher than that of the polarizing films A to C of Comparative Examples. The rate change ΔY was small, and permeation of iodine to the outside was sufficiently suppressed in a hot and humid environment. Furthermore, the polarizing film C having a TAC film as a transparent protective film tended to be superior to the polarizing film B in crack resistance.

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

Claims (18)

a polarizer containing iodine;
A resin layer containing a polymer having at least one selected from the group consisting of a structural unit U1 derived from a compound A1 containing an epoxy group and a structural unit U2 derived from a compound A2 containing an oxetane group,
A polarizing film, wherein the value of y calculated by the following formula (1) is less than 4.00.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer for forming the polymer,
_x2 is the x component (Debye) in the dipole moment of the monomer to form the polymer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules to form the polymer;
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. (g/100 g) of the monomer to form the polymer;
_x5 is the dipole moment (Debye) of the monomer to form the polymer;
_x6 is the z component (Debye) in the dipole moment of the monomer to form the polymer;
_x7 is the number of hydrogen bond acceptors in the monomer to form the polymer. The polarizing film according to claim 1, wherein the value of y is 2.30 or less. The polarizing film according to claim 1, wherein the polymer contains both the structural unit U1 and the structural unit U2. The polarizing film according to claim 1, wherein the total content of the structural unit U1 and the structural unit U2 in the polymer is 70% by weight or more. The polarizing film according to claim 1, wherein the compound A1 contains a ring structure other than an epoxy group. The polarizing film according to claim 1, wherein the compound A1 contains at least one selected from the group consisting of an aliphatic ring and an aromatic ring. The polarizing film according to claim 1, wherein the resin layer contains an acid generator and/or a decomposition product of the acid generator. The polarizing film according to claim 1, wherein the resin layer is in direct contact with the polarizer. The polarizing film according to claim 1, wherein the resin layer has a thickness of less than 3 µm. The polarizing film according to claim 1, wherein the polarizer has a thickness of 1 μm or more and less than 7 μm. The polarizing film according to claim 1, wherein the polarizer contains polyvinyl alcohol as a main component. The polarizing film according to claim 1, further comprising a protective film. The polarizing film according to claim 12, wherein the protective film, the resin layer and the polarizer are arranged in this order in the stacking direction. The polarizing film according to claim 12, wherein the protective film has a moisture permeability of 300 g/(m ² ·day) or more. The polarizing film according to claim 12, wherein the protective film contains triacetylcellulose as a main component. The polarizing film according to claim 12, wherein the protective film has a thickness of less than 40 µm. A polarizing film according to any one of claims 1 to 16,
an image display panel;
An image display device. A resin layer containing a polymer having at least one selected from the group consisting of a polarizer containing iodine, a structural unit U1 derived from a compound A1 containing an epoxy group, and a structural unit U2 derived from a compound A2 containing an oxetane group. And, a method for producing a polarizing film comprising
The manufacturing method is
A method for producing a polarizing film, comprising the step of polymerizing a monomer having a y value of less than 4.00 calculated by the following formula (1) to obtain the polymer.
y=(-3.71) _x1 +(-3.94) _x2 +(0.299) _x3 +(0.226) _x4 +(-1.05) _x5 +(0.517) _x6 +(0.769) _x7+ 71.81 (1 )
In the formula (1), x ₁ is the dispersion term δD (MPa ^1/2 ) in the Hansen solubility parameter of the monomer,
_x2 is the x component (Debye) in the dipole moment of the monomer;
x ₃ is the interaction energy (kcal/mol) between the monomer and water molecules,
x ₄ is the common logarithm value LogS of the solubility in water at 25° C. of the monomer (g/100 g);
x ₅ is the dipole moment (Debye) of the monomer,
x ₆ is the z component (Debye) in the dipole moment of the monomer,
_x7 is the number of hydrogen bond acceptors in the monomer.

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