WO2021261303A1

WO2021261303A1 - Polarization film and method for manufacturing same, and display device

Info

Publication number: WO2021261303A1
Application number: PCT/JP2021/022410
Authority: WO
Inventors: 貴道猪股
Original assignee: 日本ゼオン株式会社
Priority date: 2020-06-24
Filing date: 2021-06-11
Publication date: 2021-12-30
Also published as: TW202200697A

Abstract

This polarization film is configured such that: a first resin layer, a polarizer layer, and a second resin layer are provided in this order; the first resin layer and/or the second resin layer is a specific resin layer formed from a specific thermoplastic resin containing an antiplasticizer of 0.5-23% by weight and a polymer; the moisture vapor permeability per 100 μm in the thickness of a first sample resin obtained by heating the specific thermoplastic resin to 250 °C, is within a specific range; and the average linear expansion coefficient at 70-85 °C of the first sample resin is smaller than the average linear expansion coefficient at 70-85 °C of a second sample resin obtained by heating to 250 °C a comparison resin having a composition excluding the antiplasticizer from the specific thermoplastic resin.

Description

Polarizing film, its manufacturing method, and display device

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

Generally, the polarizing film includes a polarizing element layer and protective film layers provided on both sides of the polarizing element layer. As such a protective film layer, a film formed of a resin composition containing a cellulose ester has often been used (Patent Document 1).

On the other hand, Non-Patent Document 1 is known.

International Publication No. 2018/230122

The polarizing film may be used in an environment with large temperature changes. Therefore, the polarizing film is required to have excellent resistance to temperature changes. Resistance to temperature changes can be assessed, for example, by heat cycle tests involving repeated heating and cooling. However, when the conventional polarizing film is subjected to a heat cycle test, cracks may occur in the polarizing element layer at the end thereof. Further, in recent years, bezel-free, curved and the like have been adopted for the display body, and the required quality of the end portion of the polarizing film is increasing.

The present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to provide a polarizing film having excellent resistance to temperature changes and a method for producing the same; and a display device including the above-mentioned polarizing film. ..

The present inventor has diligently studied to solve the above-mentioned problems. As a result, in the polarizing film including the first resin layer, the copolymer layer and the second resin layer in this order, at least one of the first resin layer and the second resin layer is a polymer and the reverse of a specific amount. The present invention has been completed by finding that the above-mentioned problems can be solved when the specific resin layer is formed of a thermoplastic resin containing a plasticizer and the specific resin layer satisfies a specific requirement.
That is, the present invention includes the following.

[1] A first resin layer, a polarizing element layer, and a second resin layer are provided in this order.
At least one of the first resin layer and the second resin layer is a specific resin layer formed of a specific thermoplastic resin containing a polymer and a back plasticizer.
The amount of the reverse plasticizer is 0.5% by weight or more and 23% by weight or less with respect to 100% by weight of the specific thermoplastic resin.
The water vapor transmittance per 100 μm thickness of the first sample resin obtained by heating the specific thermoplastic resin to 250 ° C. is 4 g / (m ² · day) or less.
A polarizing film satisfying the following formula (1).
CTE (I) / CTE (II) <1 (1)
(In equation (1)
CTE (I) represents the average linear expansion coefficient of the first sample resin at 70 ° C to 85 ° C.
CTE (II) represents the average linear expansion coefficient of the second sample resin obtained by heating a contrasting resin having a composition obtained by removing the backplasticizer from the specific thermoplastic resin to 250 ° C. at 70 ° C. to 85 ° C. .. )
[2] The polarizing film according to [1], wherein a first adhesive layer is provided between the first resin layer and the polarizing element layer.
[3] The polarizing film according to [1] or [2], wherein a second adhesive layer is provided between the polarizing element layer and the second resin layer.
[4] The in-plane retardation of the specific resin layer at a measurement wavelength of 550 nm is 5 nm or less.
The polarizing film according to any one of [1] to [3], wherein the retardation of the specific resin layer in the thickness direction at a measurement wavelength of 550 nm is -5 nm or more and 5 nm or less.
[5] The polarizing film according to any one of [1] to [4], wherein the specific thermoplastic resin contains a polymer containing an alicyclic structure.
[6] The polarizing film according to any one of [1] to [5], wherein the specific resin layer has a thickness of 9 μm or less.
[7] The polarizing film according to any one of [1] to [6], wherein the polarizing element layer has a thickness of 19 μm or less.
[8] The polarizing film according to any one of [1] to [7], wherein the specific thermoplastic resin contains 0.010% by weight or more and 10.0% by weight or less of a solvent.
[9] The polarizing film according to any one of [1] to [8], wherein the reverse plasticizer is a terphenyl compound.
[10] The polarizing film according to any one of [1] to [9], wherein the pressure-sensitive adhesive layer, the first resin layer, the polarizing element layer, and the second resin layer are provided in this order.
[11] The polarizing film according to [10], wherein a λ / 4 layer is provided between the pressure-sensitive adhesive layer and the first resin layer.
[12] The method for producing a polarizing film according to any one of [1] to [11].
A step of applying a resin solution containing a polymer, a reverse plasticizer and a solvent on a temporary substrate, and
A step of drying the resin liquid to obtain a specific resin layer formed of the specific thermoplastic resin, and a step of obtaining the specific resin layer.
The step of bonding the specific resin layer and the polarizing element layer, and
A method for producing a polarizing film, comprising the step of peeling off the temporary substrate in this order.
[13] The method for producing a polarizing film according to [12], which comprises a step of forming an adhesive layer.
[14] A display device including a display body and the polarizing film according to any one of [1] to [11].
A display device in which the polarizing film includes a first resin layer, a polarizing element layer, and a second resin layer in this order from the display body side.
[15] The display device according to [14], wherein the display body is a liquid crystal panel.
[16] The display device according to [14], wherein the display body is an organic electroluminescence panel.

According to the present invention, it is possible to provide a polarizing film having excellent resistance to temperature changes and a method for producing the same; and a display device including the above-mentioned polarizing film.

FIG. 1 is a cross-sectional view schematically showing a polarizing film according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a polarizing film according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be arbitrarily modified and carried out without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, "long" refers to a shape having a length of usually 5 times or more with respect to the width, preferably 10 times or more, and specifically a roll shape. A shape that has a length that allows it to be wound up and stored or transported. The upper limit of the ratio of the length to the width is not particularly limited, but may be, for example, 100,000 times or less.

In the following description, the adhesive and the adhesive are distinguished by the shear storage elastic modulus unless otherwise specified. Specifically, unless otherwise specified, the adhesive refers to a material having a shear storage elastic modulus of 1 MPa to 500 MPa at 23 ° C. after irradiation with energy rays or after heat treatment. Unless otherwise specified, the pressure-sensitive adhesive refers to a material having a shear storage elastic modulus of less than 1 MPa at 23 ° C.

In the following description, the in-plane retardation Re of a certain layer is a value represented by Re = (nx-ny) × d unless otherwise specified. Further, the retardation Rth in the thickness direction of a certain layer is a value represented by Rth = [{(nx + ny) / 2} -nz] × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and in the direction giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and perpendicular to the direction of nx. nz represents the refractive index in the thickness direction of the layer. d represents the thickness of the layer. The measurement wavelength is 550 nm unless otherwise specified.

In the following description, (meth) acrylic resin includes acrylic resin, methacrylic resin, and combinations thereof unless otherwise specified. Further, (meth) acrylic acid includes acrylic acid, methacrylic acid and combinations thereof unless otherwise specified.

In the following description, the "plate", "layer" and "film" may be a rigid member, and may be a flexible member such as a resin film, unless otherwise specified. May be good.

[1. Overview of polarizing film]
FIG. 1 is a cross-sectional view schematically showing a polarizing film 100 according to an embodiment of the present invention. As shown in FIG. 1, the polarizing film 100 according to the embodiment of the present invention includes a first resin layer 110, a polarizing element layer 120, and a second resin layer 130 in this order in the thickness direction.

At least one of the first resin layer 110 and the second resin layer 130 included in the polarizing film 100 is formed of a specific thermoplastic resin. Hereinafter, this specific thermoplastic resin may be referred to as "specific thermoplastic resin". Further, the layer formed of the specific thermoplastic resin may be referred to as a "specific resin layer".

Normally, the specific resin layer functions as a protective film layer of the polarizing element layer 120. As described above, the polarizing film 100 provided with the specific resin layer can have excellent resistance to temperature changes. Specifically, it is possible to suppress the occurrence of cracks in the polarizing element layer due to temperature changes.

For example, only the first resin layer 110 may be a specific resin layer. Further, for example, only the second resin layer 130 may be the specific resin layer. Further, both the first resin layer 110 and the second resin layer 130 may be the specific resin layer. Above all, it is preferable that at least the first resin layer 110 is a specific resin layer. When the polarizing film is provided in the display device, the polarizing film 100 is usually provided so that the first resin layer 110, the polarizing element layer 120, and the second resin layer 130 are arranged in this order from the display body side. At this time, when the first resin layer 110 located between the display body and the polarizing element layer 120 is the specific resin layer, the occurrence of cracks in the polarizing element layer 120 can be effectively suppressed.

FIG. 2 is a sectional view schematically showing a polarizing film 200 according to another embodiment of the present invention. As shown in FIG. 2, the polarizing film 200 may further include any layer in combination with the first resin layer 110, the polarizing element layer 120, and the second resin layer 130. For example, the polarizing film 200 may include a first adhesive layer 210 as an arbitrary layer between the first resin layer 110 and the polarizing element layer 120. Further, for example, the polarizing film 200 may include a second adhesive layer 220 as an arbitrary layer between the polarizing element layer 120 and the second resin layer 130. Further, for example, the polarizing film 200 may include the pressure-sensitive adhesive layer 230, the first resin layer 110, the polarizing element layer 120, and the second resin layer 130 as arbitrary layers in this order. Further, for example, a λ / 4 layer 240 may be provided as an arbitrary layer between the pressure-sensitive adhesive layer 230 and the first resin layer 110.

[2. Specific resin layer]
[2.1. Polymer contained in specific thermoplastic resin]
The specific thermoplastic resin forming the specific resin layer contains a polymer. Usually, since the polymer has thermoplasticity, the specific thermoplastic resin may also have thermoplasticity.

Examples of the polymer contained in the specific thermoplastic resin include polyesters, acrylic polymers, and polymers containing an alicyclic structure. One of these polymers may be used alone, or two or more of these polymers may be used in combination at any ratio. Above all, a polymer containing an alicyclic structure is preferable from the viewpoint of lowering the water vapor permeability of the specific resin layer.

In a polymer containing an alicyclic structure, the repeating unit of the polymer contains an alicyclic structure. Polymers containing an alicyclic structure usually have a low water vapor permeability. Therefore, when the specific resin layer is formed of the specific thermoplastic resin containing the polymer containing the alicyclic structure, it is possible to effectively suppress the water vapor from reaching the substituent layer.

The polymer containing an alicyclic structure may contain an alicyclic structure in the main chain or may contain an alicyclic structure in the side chain, and the alicyclic structure may be contained in both the main chain and the side chain. It may contain a cyclic structure. Above all, from the viewpoint of mechanical strength and heat resistance, a polymer having an alicyclic structure at least in the main chain is preferable.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among them, a cycloalkane structure and a cycloalkene structure are preferable, and a cycloalkane structure is particularly preferable, from the viewpoint of mechanical strength and heat resistance.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly preferably 20 or less, per alicyclic structure. Is in the range of 15 or less. When the number of carbon atoms constituting the alicyclic structure is in this range, the mechanical strength, heat resistance and moldability of the specific thermoplastic resin are highly balanced.

In the polymer containing an alicyclic structure, the ratio of the repeating unit containing the alicyclic structure can be appropriately selected according to the purpose of use. The proportion of the repeating unit containing the alicyclic structure in the polymer containing the alicyclic structure is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the ratio of the repeating unit containing the alicyclic structure in the polymer containing the alicyclic structure is in this range, the transparency and heat resistance of the specific thermoplastic resin are improved.

Examples of the polymer containing an alicyclic structure include a norbornene-based polymer, a monocyclic cyclic olefin-based polymer, a cyclic conjugated diene-based polymer, a vinyl alicyclic hydrocarbon polymer, and hydrides thereof. Can be mentioned. Among these, the norbornene-based polymer and its hydride have good transparency and moldability.

Examples of the norbornene-based polymer and its hydride include a ring-opening polymer of a monomer having a norbornene structure and a hydride thereof; an addition polymer of a monomer having a norbornene structure and a hydride thereof. Examples of the ring-opening polymer of the monomer having a norbornene structure include a ring-opening copolymer of one kind of monomer having a norbornene structure and ring-opening of two or more kinds of monomers having a norbornene structure. Examples thereof include a copolymer and a ring-opening copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Further, examples of the addition polymer of the monomer having a norbornene structure are an addition homopolymer of one kind of monomer having a norbornene structure and an addition copolymer of two or more kinds of monomers having a norbornene structure. , And addition copolymers of a monomer having a norbornene structure and any monomer copolymerizable therewith. Examples of these polymers include polymers disclosed in JP-A-2002-321302.

Specific examples of the norbornene-based polymer and its hydride include "Zeonoa" manufactured by Zeon Corporation; "Arton" manufactured by JSR Corporation; "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

The weight average molecular weight Mw of the polymer contained in the specific thermoplastic resin is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, preferably 100,000 or less, more preferably 100,000 or less. It is 80,000 or less, particularly preferably 50,000 or less. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the specific thermoplastic resin are highly balanced.

The molecular weight distribution (Mw / Mn) of the polymer contained in the specific thermoplastic resin is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3.5 or less. It is more preferably 3.0 or less, and particularly preferably 2.7 or less. Here, Mn represents a number average molecular weight. When the molecular weight distribution is at least the lower limit of the above range, the productivity of the polymer can be increased and the production cost can be suppressed. Further, when the molecular weight distribution is not more than the upper limit of the above range, the amount of the small molecule component becomes small, so that relaxation during high temperature exposure can be suppressed and the stability of the specific resin layer can be enhanced.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by using gel permeation chromatography (GPC). Examples of the solvent used in GPC include cyclohexane, toluene, and tetrahydrofuran. When GPC is used, the weight average molecular weight can be measured as a relative molecular weight in terms of polyisoprene or polystyrene, for example.

The glass transition temperature of the polymer contained in the specific thermoplastic resin is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, further preferably 120 ° C. or higher, preferably 170 ° C. or lower, more preferably 160 ° C. or lower, More preferably, it is 150 ° C. or lower. When the glass transition temperature of the polymer is in the above range, the durability of the polarizing film in a high temperature environment can be enhanced. The glass transition temperature can be measured by raising the temperature at 10 ° C./min using a differential scanning calorimeter (DSC).

The amount of the polymer contained in the specific thermoplastic resin is preferably 70% by weight or more, more preferably 80% by weight or more, still more preferably 85% by weight or more, and usually, with respect to 100% by weight of the specific thermoplastic resin. It is 99% by weight or less, preferably 96% by weight or less, and more preferably 93% by weight or less. When the amount of the polymer contained in the specific thermoplastic resin is within the above range, the generation of cracks in the polarizing element layer due to temperature changes can be effectively suppressed.

[2.2. Reverse plasticizer contained in specific thermoplastic resin]
The specific thermoplastic resin forming the specific resin layer contains a back plasticizer. The back plasticizer represents a compound in which the specific thermoplastic resin containing the back plasticizer can satisfy the following formula (1).

CTE (I) / CTE (II) <1 (1)
(In equation (1)
CTE (I) represents the average linear expansion coefficient of the first sample resin obtained by heating the specific thermoplastic resin to 250 ° C. at 70 ° C. to 85 ° C.
CTE (II) represents the average linear expansion coefficient of the second sample resin obtained by heating a comparative resin having a composition obtained by removing a back plasticizer from a specific thermoplastic resin to 250 ° C. at 70 ° C. to 85 ° C. )

Equation (1) will be described in detail.
CTE (I) represents the average coefficient of linear expansion of the first sample resin at 70 ° C to 85 ° C. The first sample resin represents a resin obtained by heating a specific thermoplastic resin to 250 ° C. Usually, this first sample resin corresponds to a non-volatile component obtained by removing a volatile component removed by heating at 250 ° C. from a specific thermoplastic resin. Therefore, the average linear expansion coefficient CTE (I) of the first sample resin can represent the average linear expansion coefficient of the non-volatile component of the specific thermoplastic resin including the polymer and the back plasticizer.

CTE (II) represents the average linear expansion coefficient of the second sample resin at 70 ° C to 85 ° C. The second sample resin represents a resin obtained by heating the contrast resin to 250 ° C. Usually, this second sample resin corresponds to a non-volatile component obtained by removing the volatile component removed by heating at 250 ° C. from the contrast resin. Further, the contrast resin represents a resin having a composition obtained by removing the back plasticizer from the specific thermoplastic resin. Therefore, the linear expansion coefficient CTE (II) of the second sample resin can represent the linear expansion coefficient of the non-volatile component of the contrast resin having the same composition as the specific thermoplastic resin except that it does not contain a back plasticizer.

Therefore, the formula (1) is usually compared with the non-volatile component of the contrast resin having the same composition as the specific thermoplastic resin except that the non-volatile component of the specific thermoplastic resin containing the back plasticizer does not contain the back plasticizer. , 70 ° C to 85 ° C, indicating that it has a small average linear expansion coefficient. As can be seen from this equation (1), the reverse plasticizer can be a component capable of exerting an action of reducing the coefficient of linear expansion of the resin.

The ratio CTE (I) / CTE (II) of the linear expansion coefficient is preferably 0.90 or less, more preferably 0.80 or less, and particularly preferably 0.70 or less. The lower limit is not particularly limited, but is usually 0.00 or more. When the ratio CTE (I) / CTE (II) of the linear expansion coefficient is in the above range, the generation of cracks in the polarizing element layer due to the temperature change can be effectively suppressed.

The average linear expansion coefficient CTE of a sample resin obtained by heating a certain thermoplastic resin to 250 ° C. at 70 ° C. to 85 ° C. can be measured by the following method.
The thermoplastic resin is thermally melted and molded using a heat melting press machine under the conditions of a clearance of 10 μm, a temperature of 250 ° C., and a pressure of 30 MPa to obtain a measuring film having a thickness of 10 μm formed of the sample resin. Using this measuring film, the coefficient of linear expansion is measured by heating the temperature from 20 ° C. to 200 ° C. at 5 ° C./min with a thermomechanical analyzer. An average value of 70 ° C to 85 ° C can be obtained as the average linear expansion coefficient CTE of the sample resin.

The coefficient of linear expansion ratio CTE (I) / CTE (II) depends, for example, on the type and amount of polymer, the type and amount of reverse plasticizer, and the type and amount of any component used as needed. Can be adjusted.

In general, the reverse plasticizer as described above can enter the free volume between the polymer molecules by being mixed with the polymer, and can reduce the fraction of the free volume in the space. Therefore, since the range in which the polymer molecule can move is narrowed, the physical characteristics of the polymer and the resin containing the reverse plasticizer can change from the physical characteristics of the polymer. The change in physical properties can appear not only as the above-mentioned decrease in the coefficient of linear expansion but also as an increase in the elastic modulus in the glass state. The action of such a reverse plasticizer can be the opposite of plasticizing with a plasticizer that can penetrate between the polymer molecules and increase the fraction of free volume. Therefore, the action of the above-mentioned reverse plasticizer is sometimes called "reverse plasticization".

Examples of the reverse plasticizer include those described in JP-A-2007-326938, International Publication No. 2018/230122, and the like. As a specific backplasticizer, it is preferable to select and use one that is effective in suppressing cracks in the polarizing element layer from among those backplasticizers. Among them, particularly preferable reverse plasticizers include compounds represented by either the following formula (X1) or (X2).

In formula (X1), R ¹¹ to R ¹³ each independently represent a substituent; p1 and r1 each independently represent an integer of 0 to 5, and q1 represents an integer of 0 to 4. n represents an integer of 0 to 5. When n is 2 or more, ^{the bonding positions of the plurality of R 12} , q1 and phenylene groups may be the same or different, respectively.

When n is 0 in the formula (X1), the compound represented by the formula (X1) corresponds to a biphenyl compound. When n is 1, the compound represented by the formula (X1) corresponds to a terphenyl compound. When n is 1 or more, the bond between the benzene rings may be ortho, meta, or para.

In the formula (X1), the substituents R ¹¹ to R ¹³ include, for example, a halogen atom such as a chlorine atom; an alkyl group having 1 to 3 carbon atoms such as a methyl group; and a carbon atom number 1 to 1 such as a methoxy group. 3 alkoxy groups; Further, these substituents may further have a substituent. When there are a plurality of substituents R ¹¹ to R ¹³ , they may be the same or different.

In the formula (X1), when n is 2 or more, the plurality of R ^12s may be the same or different. Further, the n q1s may be the same or different. Further, the bonding position of n phenylene groups may be any of ortho, para, and meta.

In formula (X2), R ²¹ to R ²³ each independently represent a substituent; p2 and r2 each independently represent an integer of 0-5; q2 represents an integer of 0-4; m1 and m2 each independently represent an integer of 1 to 5. When m1 is 2 or more, ^{the bonding positions of the plurality of R 22} , q2, and phenylene groups may be the same or different, respectively. When one or both of m1 and m2 are 2 or more, the bonding order of the methylene group and the phenylene group may be random.

In formula (X2), R ²¹ to R ²³ may be the same as ^{substituents R 11} to R ¹³ in formula (X1).
In the formula (X2), when m1 is 2 or more, the plurality of R ^22s may be the same or different. Further, m1 q2 may be the same or different. Further, the bonding position of m1 phenylene group may be any of ortho, para, and meta.
In the formula (X2), the unit enclosed by m1 and the unit enclosed by m2 may be connected in no particular order. For example, there may be a form in which both units are alternately connected, a form in which a unit enclosed in m2 exists between units enclosed in m1, and the like.

Among these, biphenyl compounds and terphenyl compounds are preferable. The biphenyl compound is a compound in which two benzene rings are bonded, and the benzene ring may have a substituent such as a chlorine atom. Further, the terphenyl compound is a compound in which three benzene rings are bonded, and the benzene ring may have a substituent such as a chlorine atom. Among them, the biphenyl compound represented by the following formula (X3), the orthoterphenyl compound represented by the formula (X4), the metaterphenyl compound represented by the formula (X5), and the formula (X6) are represented. The paraterphenyl compound to be used is particularly preferable.

In formula (X3), R ³¹ and R ³² each independently represent a substituent; p3 and q3 each independently represent an integer of 0-5. In the formula (X3), the substituents R ³¹ and ³² can be the same as ^{the substituents R 11} to R ¹³ of the formula (X1). Of these, the substituents R ³¹ and ³² are preferably chlorine atoms. Further, p3 and q3 are preferably 0.

In formula (X4), R ⁴¹ to R ⁴³ each independently represent a substituent; p4 and q4 each independently represent an integer of 0 to 5, and r4 represents an integer of 0 to 4. In the formula (X4), the substituents R ⁴¹ to R ⁴³ may be the same as ^{the substituents R 11} to R ^{13 in} the formula (X1). Of these, the substituents R ⁴¹ to R ⁴³ are preferably chlorine atoms. Further, 0 is preferable for p4, q4 and r4.

In formula (X5), R ⁵¹ to R ⁵³ each independently represent a substituent; p5 and r5 each independently represent an integer of 0 to 5, and q5 represents an integer of 0 to 4. In the formula (X5), the substituents R ⁵¹ to R ⁵³ may be the same as ^{the substituents R 11} to R ^{13 in} the formula (X1). Of these, the substituents R ⁵¹ to R ⁵³ are preferably chlorine atoms. Further, 0 is preferable for p5, q5 and r5.

In formula (X6), R ⁶¹ to R ⁶³ each independently represent a substituent; p6 and r6 each independently represent an integer of 0 to 5, and q6 represents an integer of 0 to 4. In the formula (X6), the substituents R ⁶¹ to R ⁶³ can be the same as ^{the substituents R 11} to R ^{13 in} the formula (X1). Of these, the substituents R ⁶¹ to R ⁶³ are preferably chlorine atoms. Further, 0 is preferable for p6, q6 and r6.

Among these, the unsubstituted terphenyl shown below is preferable, and meta-terphenyl is particularly preferable.

As the reverse plasticizer, one type may be used alone, or two or more types may be used in combination at any ratio.

Normally, the back plasticizer has a molecular weight smaller than the weight average molecular weight of the polymer contained in the specific thermoplastic resin. The specific molecular weight of the backplasticizer is usually less than 10,000, preferably 1000 or less, more preferably 800 or less, particularly preferably 600 or less, and usually 150 or more.

The amount of the backplasticizer contained in the specific thermoplastic resin is usually 0.5% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, based on 100% by weight of the specific thermoplastic resin. It is usually 23% by weight or less, preferably 20% by weight or less, and more preferably 17% by weight or less. When the amount of the back plasticizer contained in the specific thermoplastic resin is within the above range, the cracking of the polarizing element layer due to the temperature change can be suppressed, so that the polarizing film can have excellent resistance to the temperature change.

The amount of the backplasticizer contained in the specific thermoplastic resin is preferably 0.5 parts by weight or more, more preferably 1.0 part by weight or more, particularly, with respect to 100 parts by weight of the polymer contained in the specific thermoplastic resin. It is preferably 2 parts by weight or more, preferably 30 parts by weight or less, more preferably 25 parts by weight or less, and particularly preferably 20 parts by weight or less. When the amount of the back plasticizer contained in the specific thermoplastic resin is within the above range, the occurrence of cracks in the polarizing element layer due to temperature changes can be effectively suppressed.

[2.3. Solvents that can be contained in specific thermoplastic resins]
The specific thermoplastic resin may further contain a solvent in combination with the polymer and the back plasticizer. This solvent may be a residual solvent that remains without being removed by drying among the solvents contained in the resin liquid used in the step of forming the specific resin layer. Therefore, as an example of the solvent, the same example as the solvent that can be contained in the resin liquid can be mentioned. Further, the solvent may be one kind or two or more kinds.

The amount of the solvent contained in the specific thermoplastic resin is preferably within a specific range. Specifically, the amount of the solvent contained in the specific thermoplastic resin is preferably 0.010% by weight or more, more preferably 0.10% by weight or more, and particularly preferably 0.10% by weight or more, based on 100% by weight of the specific thermoplastic resin. It is 1.0% by weight or more, preferably 10.0% by weight or less, more preferably 8.0% by weight or less, and particularly preferably 5.0% by weight or less. The specific resin layer formed of the specific thermoplastic resin containing the solvent in the specific range is excellent in transferability. "Transferability" represents a property that can suppress breakage due to transfer. Further, "transfer" of a certain layer means to move the layer from one member to the other member, and after peeling the layer from one member, the layer is attached to the other member. And, after attaching the layer on one member to the other member, removing one member. When the specific resin layer has excellent transferability, it is possible to suppress breakage of the specific resin layer due to operations such as bonding of the specific resin layer and the polarizing element layer and peeling of the temporary base material. Therefore, the polarizing film can be easily manufactured.

The amount of the solvent contained in the specific thermoplastic resin can be measured by the following measuring method.
The specific thermoplastic resin is weighed and mixed with a diluting solvent to prepare a sample solution. This sample solution is analyzed using a gas chromatograph mass spectrometer (“GC-2010Plus” manufactured by Shimadzu Corporation; the column is “DB-5HT” manufactured by Agilent technologies, 30 m × 0.25 mm, film thickness 0.1 μm). The amount of the solvent is measured based on the detection peak of the obtained solvent.

The amount of the solvent contained in the specific thermoplastic resin can be adjusted, for example, by the drying conditions of the resin liquid in the method for producing a polarizing film.

When the type of the solvent contained in the specific thermoplastic resin is known in advance, a solvent of a type different from the solvent contained in the specific thermoplastic resin is used as the diluting solvent for preparing the sample solution.
On the other hand, when the type of the solvent contained in the specific thermoplastic resin is not known in advance, the measurement using only one type of diluting solvent is sufficient for the specific thermoplastic resin of the same type of solvent as the diluted solvent. It may not be possible to measure the amount. Therefore, in that case, the amount of the solvent contained in the specific thermoplastic resin can be measured by changing the type of the diluting solvent and performing the measurement a plurality of times.

[2.4. Any component that can be contained in the specified thermoplastic resin]
The specific thermoplastic resin may further contain any component in combination with the above-mentioned polymer, backplasticizer and solvent. Optional components include, for example, hygroscopic agents; dispersants; organometallic compounds; stabilizers such as antioxidants, UV absorbers, light stabilizers; resin modifiers such as lubricants; colorants such as dyes and pigments; Antistatic agents; etc. Any component may be used alone or in combination of two or more at any ratio.

[2.5. Water vapor permeability of the first sample resin obtained from the specified thermoplastic resin]
The first sample resin obtained by heating the specific thermoplastic resin to 250 ° C. usually has a water vapor permeability in a specific range. Specifically, the water vapor transmittance per 100 μm of the thickness of the first sample resin is usually 4.0 g / (m ² · day) or less, preferably 3.0 g / (m ² · day) or less, and particularly preferably 1. It is 0.0 g / (m ² · day) or less. The lower limit is ideally 0 g / (m ² · day) or more, and ^{may be 0.1 g / (m 2} · day) or more.

As described above, the first sample resin corresponds to the non-volatile component obtained by removing the volatile component removed by heating at 250 ° C. from the specific thermoplastic resin. Therefore, the fact that the first sample resin has a small water vapor permeability as described above means that the polymer contained in the non-volatile component of the specific thermoplastic resin has an attribute suitable for achieving a small water vapor permeability. show. For example, it represents that the molecule of the polymer has a small polarity. Then, since the specific resin layer formed of the specific thermoplastic resin containing the polymer having such an attribute in combination with the above-mentioned reverse plasticizer can suppress the cracking of the polarizing element layer due to the temperature change, the polarizing film can be heated. Can have excellent resistance to change.

Further, since the first sample resin corresponds to the non-volatile component of the specific thermoplastic resin, the first sample resin corresponds to the component that can be contained in the specific thermoplastic resin for a long period of time. When the first sample resin has a water vapor permeability of not more than the upper limit value, the specific thermoplastic resin can usually have a high water vapor blocking ability for a long period of time. Therefore, the specific resin layer can stably suppress the infiltration of water into the polarizing element layer, and can effectively suppress the decrease in the degree of polarization of the polarizing element layer due to the water content.

The water vapor transmittance per 100 μm thickness of the sample resin obtained by heating a certain thermoplastic resin to 250 ° C. can be measured by the following method.
The thermoplastic resin is thermally melted and molded using a heat melting press machine under the conditions of a clearance of 100 μm, a temperature of 250 ° C., and a pressure of 30 MPa to obtain a measuring film having a thickness of 100 μm formed of the sample resin. Using this measuring film, the thickness of the sample resin is 100 μm under the conditions of temperature 40 ° C. and humidity 90% RH according to the JIS K 7129 B method by a water vapor transmission rate measuring device (“PERMATRAN-W” manufactured by MOCON). The water vapor transmission rate per hit can be measured.

The water vapor permeability of the first sample resin can be adjusted, for example, by the type and amount of the polymer contained in the specific thermoplastic resin.

[2.6. Physical properties and dimensions of specific resin layer]
The polymer molecules contained in the specific resin layer preferably have a small degree of orientation, and more preferably not oriented. When the specific thermoplastic resin composition contains a polymer having a small degree of orientation in combination with a back plasticizer, the specific resin layer formed of the specific thermoplastic resin composition cracks in the polarizing element layer due to a temperature change. Can be effectively suppressed.

The degree of orientation of the polymer molecules contained in the specific resin layer can be expressed by the optical anisotropy of the specific resin layer. Usually, when the degree of orientation of the molecules of the polymer is small, the optical anisotropy of the specific resin layer is small. Therefore, the specific resin layer preferably has low optical anisotropy in both the in-plane direction and the thickness direction, and more preferably has optical anisotropy.

Therefore, the in-plane retardation of the specific resin layer is preferably small. Specifically, the in-plane retardation of the specific resin layer at a measurement wavelength of 550 nm is preferably 5 nm or less, more preferably 4 nm or less, still more preferably 3 nm or less, and particularly preferably 2 nm or less.
Further, the retardation of the specific resin layer in the thickness direction is preferably zero or close to zero. Specifically, the retardation in the thickness direction of the specific resin layer at the measurement wavelength of 550 nm is preferably -5 nm or more, more preferably -4 nm or more, still more preferably -3 nm or more, and particularly preferably -2 nm or more. Is 5 nm or less, more preferably 4 nm or less, still more preferably 3 nm or less, and particularly preferably 2 nm or less.

The specific resin layer is preferably transparent from the viewpoint of functioning as a polarizing plate protective film layer as an optical film. Therefore, it is preferable that the total light transmittance of the specific resin layer is high. The specific total light transmittance of the specific resin layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet / visible spectrometer.

The haze of the specific resin layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%. Haze can be measured using a haze meter in accordance with JIS K7361-1997.

The specific resin layer is preferably thin. The specific thickness of the specific resin layer is usually larger than 0 μm, preferably 1 μm or more, more preferably 1.5 μm or more, preferably 9 μm or less, more preferably 6 μm or less, and particularly preferably 5 μm or less. Even if the specific resin layer is thin as described above, the polarizing element layer can be effectively protected, so that a thin polarizing film can be obtained.

[3. Polarizer layer]
As the polarizing layer, a film capable of transmitting one of two linearly polarized light whose vibration directions intersect at right angles and absorbing or reflecting the other can be used. Here, the vibration direction of linearly polarized light represents the vibration direction of an electric field of linearly polarized light. Such a film usually has a polarization transmission axis, can transmit linearly polarized light having a vibration direction parallel to the polarization transmission axis, and can absorb or reflect linearly polarized light having a vibration direction perpendicular to the polarization transmission axis.

The polarizing layer is formed on a film of a polyvinyl alcohol resin containing a vinyl alcohol-based polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol, which is subjected to dyeing treatment, stretching treatment, cross-linking treatment or the like with a dichroic substance such as iodine. Examples thereof include those subjected to appropriate processing in an appropriate order and method. The polarizing layer preferably contains a polyvinyl alcohol resin.

The thickness of the polarizing element layer is preferably larger than 1 μm, more preferably 2 μm or more, particularly preferably 3 μm or more, preferably 19 μm or less, and more preferably 18 μm or less. When the thickness of the polarizing element layer is larger than the lower limit of the above range, the optical performance of the polarizing film can be sufficiently enhanced. Further, when the thickness of the polarizing element layer is not more than the upper limit of the above range, the warp of the display body can be reduced and the bending stability of the polarizing film can be effectively improved.

[4. First resin layer]
The first resin layer is a layer formed of a thermoplastic resin and can function as a protective layer for protecting the polarizing element layer. In the polarizing film, it is preferable that the first resin layer is the above-mentioned specific resin layer.

When the second resin layer included in the polarizing film is the above-mentioned specific resin layer, the first resin layer does not have to be the specific resin layer. In this case, the first resin layer may be formed of a transparent thermoplastic resin other than the specific thermoplastic resin. Examples of the thermoplastic resin other than such a specific thermoplastic resin include a resin having the same composition as the specific thermoplastic resin except that it does not contain a back plasticizer.

If the first resin layer is not a specific resin layer, there is no limit to the thickness of the first resin layer. For example, the thickness of the first resin layer may be preferably 1 μm or more, more preferably 1.5 μm or more, preferably 20 μm or less, more preferably 9 μm or less, and particularly preferably 5 μm or less.

[5. Second resin layer]
The second resin layer is a layer formed of a thermoplastic resin and can function as a protective layer for protecting the polarizing element layer. In the polarizing film, it is preferable that the second resin layer is the above-mentioned specific resin layer.

When the first resin layer included in the polarizing film is the above-mentioned specific resin layer, the second resin layer does not have to be the specific resin layer. In this case, the second resin layer may be formed of a transparent thermoplastic resin other than the specific thermoplastic resin. Examples of thermoplastic resins other than such specific thermoplastic resins include acetate resins such as triacetyl cellulose, polyester resins, and polyether sulfone resins, which are excellent in transparency, mechanical strength, thermal stability, and moisture shielding properties. Examples thereof include polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, cyclic olefin resin, (meth) acrylic resin and the like. Of these, a (meth) acrylic resin is preferable because a second resin layer having high hardness and low water vapor transmittance can be obtained.

If the second resin layer is not a specific resin layer, there is no limit to the thickness of the second resin layer. For example, the thickness of the second resin layer can be 20 μm to 100 μm.

[6. First adhesive layer]
The polarizing film may be provided with a first adhesive layer as an arbitrary layer between the first resin layer and the polarizing element layer. By using the first adhesive layer, the first resin layer and the polarizing element layer can be strongly adhered to each other.

The first adhesive layer is formed of a first adhesive that adheres the first resin layer and the polarizing element layer. Examples of the first adhesive include acrylic adhesives, epoxy adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, and polyvinyl alkyl ether adhesives. Adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene-styrene copolymers and other ethylene adhesives, ethylene- ( Examples thereof include acrylic acid ester-based adhesives such as a methyl acrylate copolymer and an ethylene-ethyl ethyl acrylate copolymer. Further, as the first adhesive, an ultraviolet curable type adhesive is preferable because the first adhesive can be cured in a short time.

The thickness of the first adhesive layer is usually larger than 0 μm, preferably 0.1 μm or more, more preferably 1 μm or more, preferably 5 μm or less, and more preferably 3 μm or less. When the thickness of the first adhesive layer is within the above range, a good appearance can be obtained, and the first resin layer and the polarizing element layer can be strongly adhered to each other.

[7. Second adhesive layer]
The polarizing film may be provided with a second adhesive layer as an arbitrary layer between the polarizing element layer and the second resin layer. By using the second adhesive layer, the polarizing element layer and the second resin layer can be strongly adhered to each other.

The second adhesive layer is formed of a second adhesive that adheres the polarizing element layer and the second resin layer. As the second adhesive, an adhesive in the range described as the first adhesive can be used. As the second adhesive, an ultraviolet curable type adhesive is preferable because the second adhesive can be cured in a short time.

The range of the thickness of the second adhesive layer can be the same as the range of the thickness of the first adhesive layer. The thickness of the first adhesive layer and the thickness of the second adhesive layer may be the same or different.

[8. Adhesive layer]
The polarizing film may include an adhesive layer as any layer. Usually, the polarizing film includes an adhesive layer as the outermost layer of the multilayer film. Above all, it is preferable that the polarizing film is provided with the pressure-sensitive adhesive layer as the outermost layer on the first resin layer side. Therefore, the polarizing film preferably includes an adhesive layer, a first resin layer, a polarizing element layer, and a second resin layer in this order in the thickness direction.

Since the adhesive layer is formed by the adhesive, it can exert adhesive strength. Due to the adhesive force of this pressure-sensitive adhesive layer, the polarizing film can be bonded to other members. For example, when a polarizing film is incorporated into a display device including a display body such as a liquid crystal panel and an organic electroluminescence panel (hereinafter, may be appropriately referred to as “organic EL panel”), the pressure-sensitive adhesive layer and the display body are attached. By matching, a polarizing film can be provided on the display body.

Examples of the adhesive include rubber adhesives, acrylic adhesives, polyvinyl ether adhesives, urethane adhesives, silicone adhesives, and polyolefin adhesives. Among them, an acrylic pressure-sensitive adhesive and a polyolefin-based pressure-sensitive adhesive are preferable from the viewpoint of heat resistance and productivity, and an acrylic-based pressure-sensitive adhesive is particularly preferable. In addition, one type of pressure-sensitive adhesive may be used alone, or two or more types may be used in combination at any ratio.

The thickness of the pressure-sensitive adhesive layer is preferably 2.0 μm or more, more preferably 5.0 μm or more, preferably 30.0 μm or less, more preferably 25.0 μm or less, and particularly preferably 20.0 μm or less. When the thickness of the pressure-sensitive adhesive layer is at least the lower limit of the above range, the adhesive strength of the pressure-sensitive adhesive layer can be increased, and the entrainment of air bubbles during bonding can be suppressed. Further, when the thickness of the pressure-sensitive adhesive layer is not more than the upper limit of the above range, the expansion and contraction behavior of the polarizing film can be suppressed, and the bezel-free can be achieved.

[9. λ / 4 layer]
The polarizing film may include a λ / 4 layer as any layer. Normally, the λ / 4 layer is provided between the pressure-sensitive adhesive layer and the first resin layer.

The λ / 4 layer has an in-plane retardation in a specific range at a wavelength of 550 nm. Specifically, the in-plane retardation of the λ / 4 layer at a wavelength of 550 nm is preferably 110 nm or more, more preferably 120 nm or more, particularly preferably 125 nm or more, preferably 165 nm or less, more preferably 155 nm or less, particularly. It is preferably 150 nm or less.

The slow axis of the λ / 4 layer is preferably at an angle of 40 ° to 50 °, more preferably 42 ° to 48 °, and particularly preferably 44 ° to 46 ° with respect to the polarization transmission axis of the polarizing element layer. .. In this case, a circularly polarizing plate can be obtained by combining the polarizing element layer and the λ / 4 layer. Therefore, the polarizing film provided with the λ / 4 layer can function as a reflection suppression film when it is provided in the display device.

The λ / 4 layer preferably has a reverse wavelength dispersion characteristic. The reverse wavelength dispersion characteristic means the property that the in-plane retardations Re (450) and Re (550) at the measurement wavelengths of 450 nm and 550 nm satisfy Re (450) <Re (550). The λ / 4 layer having the reverse wavelength dispersion characteristic can exhibit its optical function in a wide wavelength range.

The λ / 4 layer may be produced as a stretched film obtained by stretching a pre-stretched film formed of an appropriate resin, for example. Further, the λ / 4 layer is, for example, a liquid crystal curing layer obtained by forming a layer of a liquid crystal composition containing an appropriate liquid crystal compound, orienting the molecules of the liquid crystal compound, and then curing the liquid crystal composition. It may be manufactured. Above all, from the viewpoint of obtaining a thin and flexible polarizing film, the λ / 4 layer is preferably a liquid crystal curing layer. The λ / 4 layer as such a liquid crystal curing layer can be manufactured, for example, by the method described in International Publication No. 2016/121602.

[10. Any other layer]
Yet another example of any layer that the polarizing film may include is a clear hard coat layer, an anti-glare hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer and the like. As the above-mentioned arbitrary layer, only one type may be used, or two or more types may be used in combination. Further, the number of arbitrary layers may be one layer or two or more layers. Moreover, the position of any layer is not limited as long as it does not significantly impair the effectiveness of the invention.

[11. Characteristics of polarizing film]
The above-mentioned polarizing film can have excellent resistance to temperature changes. Specifically, it is possible to suppress the occurrence of cracks in the polarizing element layer due to temperature changes.

For example, in the above-mentioned polarizing film, the number of cracks generated in the polarizing element layer can be reduced when the following polarizing element crack test is performed. For example, the number of cracks can be preferably 600 or less, more preferably 500 or less, still more preferably 400 or less, and particularly preferably 300 or less.

Further, for example, in the above-mentioned polarizing film, the average length of cracks generated in the polarizing element layer can be shortened when the following polarizing element crack test is performed. For example, the average length of cracks can be preferably 80 μm or less, more preferably 70 μm or less, and particularly preferably 60 μm or less.

(Polarizer crack test)
The polarizing film is cut into 10 cm squares to obtain a square polarizing film piece. The cut is performed so that the absorption axis of the polarizing element layer contained in the polarizing film is parallel or perpendicular to the side of the obtained polarizing film piece. This polarizing film piece is pressure-bonded to a glass substrate. When the polarizing film piece does not have the pressure-sensitive adhesive layer, the glass substrate and the polarizing film piece are pressure-bonded via the pressure-sensitive adhesive. Then, autoclave treatment is performed at 50 ° C., 5 atm, and 10 minutes to obtain an evaluation sample. This evaluation sample is subjected to 20 heat cycles consisting of cooling at −40 ° C. for 30 minutes and heating at 70 ° C. for 30 minutes. After performing the heat cycle, the end of the evaluation sample is observed with an optical microscope to measure the number of cracks and their length.

Since the polarizing element layer can be effectively protected even if the specific resin layer is thin, it is usually possible to make the entire polarizing film thin. The thickness of the polarizing film is preferably 40 μm or more, more preferably 50 μm or more, particularly preferably 60 μm or more, preferably 110 μm or less, more preferably 90 μm or less, and particularly preferably 70 μm or less.

[12. Method for manufacturing polarizing film]
As long as the above-mentioned polarizing film can be obtained, the method for producing the polarizing film is not limited. For example, even if a polarizing film is manufactured by a manufacturing method including a step of molding a specific thermoplastic resin by a melt extrusion method to obtain a specific resin layer and a step of laminating the specific resin layer and a polarizing element layer. good.

Further, from the viewpoint of easily producing a multi-layer film including a specific resin layer formed of a specific thermoplastic resin containing a specific range of solvent, the polarizing film is a polymer or reverse plastic on a temporary substrate. A step of applying a resin solution containing an agent and a solvent; a step of drying the resin solution to obtain a specific resin layer formed of a specific thermoplastic resin; and a step of bonding a specific resin layer and a polarizing element layer. And; It is preferable to manufacture by a manufacturing method including the step of peeling off the temporary base material and; in this order. According to this manufacturing method, a long polarizing film can be continuously manufactured by using a long polarizing layer and a long temporary base material. Hereinafter, this manufacturing method will be described in detail.

[12.1. Process of applying resin liquid on temporary base material]
In the above-mentioned method for manufacturing a polarizing film, a step of applying a resin liquid on a temporary base material to form a layer of the resin liquid is performed. The resin liquid is a liquid material for forming a specific resin layer. Therefore, the resin liquid usually contains each component that can be contained in the specific thermoplastic resin. Specifically, the resin liquid may contain a polymer, a back plasticizer, a solvent, and optionally any component contained in the specific thermoplastic resin. Some or all of the non-volatile components such as polymers, reverse plasticizers and optional components may be dissolved in the solvent. Further, a part or all of the non-volatile component may be dispersed in a solvent.

As the solvent, an organic solvent is preferable, and an organic solvent capable of dissolving a polymer and a back plasticizer that can be contained in the specific thermoplastic resin is particularly preferable. Examples of the solvent include hydrocarbon solvents such as cyclohexane and toluene; cyclic ether solvents such as tetrahydrofuran; and the like. As the solvent, one type may be used alone, or two or more types may be used in combination at any ratio. Normally, a part of the solvent contained in the resin liquid can remain in the specific thermoplastic resin contained in the specific resin layer.

The concentration of the non-volatile component in the resin liquid can be arbitrarily set as long as the resin liquid has a viscosity suitable for coating. The specific concentration range is preferably 5% by weight or more, more preferably 10% by weight or more, particularly preferably 13% by weight or more, preferably 35% by weight or less, more preferably 30% by weight or less, and particularly preferably. It is 25% by weight or less.

As the temporary base material, a member having a surface on which the resin liquid can be applied and the specific resin layer formed on the surface can be peeled off can be used. Usually, a resin film made of a resin such as polyethylene terephthalate, polyethylene, or polypropylene is used as the temporary base material. When an ultraviolet curable adhesive is used in the bonding step between the polarizing layer and the specific resin layer, a resin film having a small absorption of UV-B is preferable. “UV-B” refers to light having a wavelength of 280 nm or more and 315 nm or less, unless otherwise specified. The surface of the temporary base material may be subjected to a mold release treatment in order to facilitate peeling of the specific resin layer.

Examples of the mold release treatment include a treatment of forming a release agent layer on the surface of the temporary base material. As the release agent, for example, a silicone-based release agent such as polydimethylsiloxane, a fluorine-based release agent such as alkyl fluoride, a long-chain alkyl-based release agent, and the like are used. Among them, a silicone-based mold release agent is preferable because of its good mold release and processability.

Examples of the method for applying the resin liquid to the temporary substrate include curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, and printing coating. Examples include a method, a gravure coating method, a die coating method, a gap coating method, and a dipping method.

[12.2. Step of drying the resin liquid to obtain a specific resin layer]
By applying the resin liquid to the temporary base material, a layer of the resin liquid is formed on the temporary base material. Therefore, after applying the resin liquid to the temporary base material, the resin liquid on the temporary base material is dried. By this drying, volatile components such as a solvent are removed from the layer of the resin liquid, so that a specific resin layer formed of the specific thermoplastic resin can be obtained.

The conditions for drying the resin liquid are preferably set so that the amount of the solvent contained in the specific thermoplastic resin contained in the specific resin layer obtained after drying falls within the above-mentioned specific range. For example, the amount of the solvent contained in the specific thermoplastic resin can be adjusted to a preferable range by appropriately setting the drying conditions such as the drying temperature and the drying time.

The specific drying temperature may vary depending on the type and amount of the polymer, the reverse plasticizer and the solvent, but is generally preferably 90 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 110 ° C. or higher. It is preferably 140 ° C. or lower, more preferably 135 ° C. or lower, and particularly preferably 130 ° C. or lower.

The specific drying time may vary depending on the type and amount of the polymer, the reverse plasticizer and the solvent, but is generally preferably 30 seconds or longer, more preferably 60 seconds or longer, and particularly preferably 90 seconds or longer. It is preferably 5 minutes or less, more preferably 4 minutes or less, and particularly preferably 3 minutes or less.

[12.3. Step of bonding the specific resin layer and the polarizing element layer]
After forming the specific resin layer on the temporary base material, a step of bonding the specific resin layer and the polarizing element layer is performed. The bonding of the specific resin layer and the polarizing element layer may be performed via an adhesive, if necessary. Usually, a long specific resin layer and a long polarizing element layer are bonded together using a bonding tool such as a pinch roller via an adhesive, if necessary.

When the amount of the solvent contained in the specific thermoplastic resin forming the specific resin layer is within the above-mentioned specific range, the breakage of the specific resin layer at the time of the above-mentioned bonding is suppressed. Therefore, the polarizing film can be manufactured with a high yield.

[12.4. Step of peeling off the temporary base material]
After the specific resin layer and the polarizing element layer are bonded together, a step of peeling off the temporary base material is performed. When the amount of the solvent contained in the specific thermoplastic resin forming the specific resin layer is within the above-mentioned specific range, the breakage of the specific resin layer at the time of peeling of the temporary base material is suppressed. Therefore, the polarizing film can be manufactured with a high yield.

Normally, the temporary base material is peeled off continuously. At this time, it is preferable that the peeling speed is appropriately set within a range in which the breakage of the specific resin layer can be suppressed. The specific peeling speed of the temporary substrate is preferably 10 m / min or more, more preferably 15 m / min or more, particularly preferably 20 m / min or more, preferably 70 m / min or less, and more preferably 60 m / min or less. Particularly preferably, it is 50 m / min or less.

[12.5. Step of forming the first resin layer or the second resin layer]
By the above-mentioned steps, the specific resin layer can be formed directly on the polarizing element layer or indirectly via arbitrary layers such as the first adhesive layer and the second adhesive layer. Therefore, for example, in the multilayer film provided with the specific resin layer as both the first resin layer and the second resin layer, the specific resin layer as the first resin layer and the specific resin layer as the second resin layer are used in the above-mentioned steps. It can be manufactured by a manufacturing method including forming on a polarizing layer. At this time, the second resin layer may be formed after the first resin layer is formed, or the first resin layer may be formed after the second resin layer is formed, and the first resin layer and the second resin layer may be formed. The resin layer may be formed at the same time. Here, "directly" forming another layer on one layer means that there is no other layer between the two layers. Also, "indirectly" providing another layer on one layer means that there is another layer between the two layers.

Further, in the case of producing a multilayer film including a first resin layer as a specific resin layer and a second resin layer other than the specific resin layer in combination, the method for producing the multilayer film is to form a second resin layer. May include steps to be performed. There are no restrictions on the method of forming the second resin layer. For example, the second resin layer can be formed by a method including laminating a second resin layer prepared in advance to the polarizing element layer via an adhesive, if necessary. This bonding usually includes bonding a long second resin layer and a long polarizing element layer using a bonding tool such as a pinch roller via an adhesive, if necessary.

Further, in the case of producing a multilayer film including a second resin layer as a specific resin layer and a first resin layer other than the specific resin layer in combination, the method for producing the multilayer film is to form the first resin layer. May include steps to be performed. There are no restrictions on the method of forming the first resin layer. For example, the first resin layer can be formed by a method including laminating a first resin layer prepared in advance to a polarizing element layer via an adhesive, if necessary. This bonding usually includes bonding a long first resin layer and a long polarizing element layer using a bonding tool such as a pinch roller via an adhesive, if necessary.

As described above, there is no limitation on the timing of forming the first resin layer or the second resin layer other than the specific resin layer. For example, the first resin layer or the second resin layer may be formed before the specific resin layer and the polarizing element layer are bonded together. Further, for example, the first resin layer or the second resin layer may be formed after the specific resin layer and the polarizing element layer are bonded together. Further, for example, the first resin layer or the second resin layer may be formed at the same time as the specific resin layer and the polarizing element layer are bonded to each other.

[12.6. Step of forming the adhesive layer]
The method for producing a polarizing film described above may include a step of forming an adhesive layer. There are no restrictions on the method of forming the pressure-sensitive adhesive layer. For example, the pressure-sensitive adhesive layer may be formed by applying a pressure-sensitive adhesive. Further, for example, the pressure-sensitive adhesive layer may be formed by bonding the pressure-sensitive adhesive layers prepared in advance.

There is no limit to the time when the adhesive layer is formed. For example, in the case of producing a multilayer film including an adhesive layer, a first resin layer and a polarizing element layer in this order, usually, after forming the first resin layer on the polarizing element layer, the adhesive layer is formed. sell.

[12.7. Arbitrary process]
The above-mentioned method for producing a polarizing film may further include an arbitrary step, if necessary. For example, when an adhesive layer such as a first adhesive layer and a second adhesive layer is provided on the polarizing film, the method for producing the polarizing film may include a step of curing the adhesive. Usually, the step of curing the adhesive is performed after the layers are bonded to each other using the above-mentioned adhesive. As the method for curing the adhesive, an appropriate method can be adopted depending on the type of the adhesive. For example, when an ultraviolet curable adhesive is used, the adhesive can be cured by irradiation with ultraviolet rays.

Further, the method for manufacturing a polarizing film may include, for example, a step of providing an arbitrary layer such as a λ / 4 layer.

Further, the method for manufacturing a polarizing film may include a step of trimming the polarizing film. For example, after producing a long polarizing film using a long polarizing element layer, a first resin layer, and a second resin layer, the polarizing film may be trimmed to a desired size.

[13. Display device]
The above-mentioned polarizing film may be provided in a display device, for example. A display device including a polarizing film usually includes a display body in combination with the polarizing film. At this time, the polarizing film may be provided so as to include the first resin layer, the polarizing element layer, and the second resin layer in this order from the display body side. This display device can be manufactured, for example, by a manufacturing method including laminating a display body and an adhesive layer of a polarizing film. However, the manufacturing method of the display device is not limited to this.

In the above display device, the polarizing element layer of the polarizing film is protected by the first resin layer and the second resin layer. Therefore, it is possible to suppress a decrease in the degree of polarization of the polarizing element layer, suppress damage to the polarizing element layer, and suppress damage to the polarizing element layer due to an external force. Further, in particular, since the specific resin layer is used as at least one of the first resin layer and the second resin layer, it is possible to suppress the generation of cracks in the polarizing element layer due to temperature changes.

Examples of the display body include a liquid crystal panel as a display body for a liquid crystal display device and an organic EL panel as a display body for an organic electroluminescence display device (hereinafter, may be appropriately referred to as an “organic EL display device”). Can be mentioned. Usually, a polarizing film is provided on the visual side of these displays.

A liquid crystal panel usually includes a liquid crystal cell and an electrode capable of applying a voltage to the liquid crystal. The liquid crystal cell has, for example, in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous spin wheel alignment (CPA) mode, hybrid alignment nematic (HAN) mode, twisted nematic. The liquid crystal cell of any mode such as (TN) mode, super twisted nematic (STN) mode, optical compensated bend (OCB) mode can be used.

The organic EL panel usually includes an organic EL element including a transparent electrode layer, a light emitting layer, and an electrode layer in this order. In this organic EL element, the light emitting layer can generate light by applying a voltage from the transparent electrode layer and the electrode layer. Examples of the material constituting the organic light emitting layer include polyparaphenylene vinylene-based materials, polyfluorene-based materials, and polyvinylcarbazole-based materials. Further, the light emitting layer may have a laminate of a plurality of layers having different emission colors, or a mixed layer in which a layer of a certain dye is doped with different dyes. Further, the organic EL element may include functional layers such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and may be arbitrarily modified and carried out without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following explanation, "%" and "part" indicating the amount are based on weight unless otherwise specified. Further, the operations described below were performed in the air at normal temperature and pressure unless otherwise specified.

[Evaluation method]
(Measurement of coefficient of linear expansion ratio)
The first resin collected in Examples and Comparative Examples was formed from the first sample resin by hot melting and molding using a heat melting press machine under the conditions of a clearance of 10 μm, a temperature of 250 ° C., and a pressure of 30 MPa. A measuring film having a thickness of 10 μm was obtained. Using this measuring film, the coefficient of linear expansion was measured by raising the temperature from 20 ° C. to 200 ° C. at 5 ° C./min using a thermomechanical analyzer (TMA; “SS7100” manufactured by SII). The average value of 70 ° C. to 85 ° C. was defined as the average linear expansion coefficient CTE (I) of the first sample resin.

Separately, a comparative resin having a composition obtained by removing the back plasticizer from the first resin prepared in Examples and Comparative Examples was prepared. Specifically, a resin solution was prepared, coated, and dried by the same method as in each Example and Comparative Example except that a reverse plasticizer was not used, to produce a layer of a comparative resin having a thickness of 2 μm. A part of the layer of the contrast resin was peeled off from the temporary base material to obtain a sample formed of the contrast resin. This contrast resin is thermally melted and molded using a heat melting press machine under the conditions of a clearance of 10 μm, a temperature of 250 ° C., and a pressure of 30 MPa to obtain a measurement film having a thickness of 10 μm formed of the second sample resin. rice field. Using this measuring film, the coefficient of linear expansion was measured by raising the temperature from 20 ° C. to 200 ° C. at 5 ° C./min using a thermomechanical analyzer. The average value from 70 ° C. to 85 ° C. was defined as the average linear expansion coefficient CTE (II) of the second sample resin.

The average linear expansion coefficient CTE (I) of the first sample resin was divided by the average linear expansion coefficient CTE (II) of the second sample resin to obtain the ratio CTE (I) / CTE (II) of the linear expansion coefficient. The first sample resin corresponds to a non-volatile component excluding the volatile component that can volatilize at 250 ° C. from the first resin. Further, the second sample resin corresponds to a non-volatile component excluding the volatile component that can volatilize at 250 ° C. from the contrast resin. Further, the first resin and the contrast resin have the same composition except for the reverse plasticizer. Therefore, the difference between the average linear expansion coefficient CTE (I) of the first sample resin and the average linear expansion coefficient CTE (II) of the second sample resin can be caused by the back plasticizer. The fact that their ratio CTE (I) / CTE (II) is smaller than 1.00 indicates that the reverse plasticizer has an effect of reducing the linear expansion coefficient of the resin.

(Measurement of water vapor permeability)
The first resin collected in Examples and Comparative Examples was formed from the first sample resin by hot melting and molding using a heat melting press machine under the conditions of a clearance of 100 μm, a temperature of 250 ° C., and a pressure of 30 MPa. A measuring film having a thickness of 100 μm was obtained. Using this measuring film, the first sample resin was prepared by a water vapor transmission rate measuring device (“PERMATRAN-W” manufactured by MOCON) under the conditions of a temperature of 40 ° C. and a humidity of 90% RH according to the JIS K 7129B method. The water vapor transmission rate per 100 μm thickness was measured.

(Measurement of letteration)
A part of the in-plane retardation Re and the thickness direction retardation Rth of the first resin layer collected in Examples and Comparative Examples were measured at a measurement wavelength of 550 nm using a phase difference meter (“Axo Scan” manufactured by AXOMETRICS). It was measured.

(Measurement of the amount of solvent contained in the first resin)
Cyclohexane, which is the residual solvent of the first resin collected in Examples and Comparative Examples, was quantified by the following GC / MS.
After weighing the first resin in a screw tube, xylene was added, and ultrasonic treatment was performed for 30 minutes to completely dissolve the sample solution. The sample solution was analyzed using a gas chromatograph mass spectrometer (“GC-2010Plus” manufactured by Shimadzu Corporation; the column was “DB-5HT” manufactured by Agilent technologies, 30 m × 0.25 mm, film thickness 0.1 μm). Cyclohexane was quantified using the obtained cyclohexane detection peak and the calibration curve obtained in advance from the cyclohexane standard solution. From the measurement results, the ratio of cyclohexane as a residual solvent in the first resin was determined.

(Evaluation of transferability of the first resin layer)
From the step of attaching the first resin layer formed on the temporary base material to the polarizing element layer to the step of peeling off the temporary base material were observed. From the observation results, the transferability of the first resin layer was evaluated according to the following criteria.
"Good": No breakage of the first resin layer occurs.
"OK": Occasionally, the first resin layer breaks.

(Crack test of polarizing layer)
A glass substrate (“Eagle XG” manufactured by Corning Inc .; thickness 0.5 mm) was prepared, and the glass surface was subjected to corona treatment.
The polarizing films produced in Examples and Comparative Examples were cut into 10 cm squares to obtain polarizing film pieces. The cut was made so that the absorption axis of the polarizing element layer contained in the polarizing film was parallel to or perpendicular to the side of the obtained polarizing film piece. The adhesive layer of this polarizing film piece was pressure-bonded to the corona-treated surface of the glass substrate using a pinch roller. Then, autoclave treatment was performed at 50 ° C., 5 atm, and 10 minutes to obtain an evaluation sample.

This evaluation sample was subjected to a heat cycle test in which a heat cycle consisting of cooling at -40 ° C for 30 minutes and heating at 70 ° C for 30 minutes was performed 20 times. The end of the evaluation sample after the test was observed with an optical microscope, and the number of cracks and their length were measured.

(Comprehensive judgment)
From the results of the transferability evaluation and the crack test, the results of each Example and Comparative Example were judged according to the following criteria.
"A": Both the transferability of the first resin layer and the crack suppressing effect are excellent.
"B": The transferability of the first resin layer is slightly inferior, but the crack suppressing effect is recognized.
"C": The crack suppressing effect is insufficient.

[Manufacturing Example 1]
As a long raw film, an unstretched polyvinyl alcohol film having a thickness of 45 μm (vinylon film, average degree of polymerization of about 2400, saponification degree of 99.9 mol%) was prepared. While continuously transporting this film in the longitudinal direction via a guide roll, the film was immersed in pure water at 30 ° C. for 1 minute and stretched twice. Then, this film was subjected to a dyeing treatment by immersing it in a dyeing solution (a dyeing solution containing iodine and potassium iodide at a weight ratio of 1:23, a dyeing agent concentration of 1.2 mmol / L) at 32 ° C. for 2 minutes. Iodine was adsorbed on the film. Then, the film was immersed in a 3 wt% boric acid aqueous solution at 35 ° C. for 30 seconds for cross-linking and washing. Then, at 57 ° C., the film was stretched 3.0 times in an aqueous solution containing 3% by weight boric acid and 5% by weight of potassium iodide. Then, the film was subjected to complementary color treatment at 35 ° C. in an aqueous solution containing 5% potassium iodide and 1.0% boric acid. Then, the film was dried at 70 ° C. for 2 minutes to obtain a long polarizing element layer having a thickness of 18 μm. The degree of polarization of this polarizing element layer was measured with an ultraviolet-visible spectrophotometer (“V-7100” manufactured by JASCO Corporation) and found to be 99.996%, which was sufficient polarization ability.

[Example 1]
(1-1. Manufacture of the first resin layer)
A norbornene-based polymer as a first polymer (“ZEONOR” manufactured by Nippon Zeon Co., Ltd .; glass transition temperature 138 ° C.) and orthoterphenyl as a back plasticizer are mixed with cyclohexane as a solvent to obtain a non-volatile component concentration of 15. A resin solution contained in% by weight was obtained. The amount of the backplasticizer was adjusted to 1% by weight based on 100% by weight of the total of the first polymer and the backplasticizer.

A long polypropylene film ("Trefan BO40-2500" manufactured by Toray Industries, Inc.) was prepared as a temporary base material. The above resin solution was applied onto this temporary substrate to form a layer of the resin solution. Then, the layer of the resin solution was dried at 120 ° C. under the drying condition for 2 minutes to obtain a long first resin layer having a thickness of 2 μm formed of the first resin. A part of this first resin layer was peeled off from the temporary base material to obtain a sample formed of the first resin. Using this sample, the ratio of linear expansion coefficient CTE (I) / CTE (II), water vapor permeability, retardation Re and Rth, and the amount of residual solvent of the first resin were measured by the above-mentioned method.

(1-2. Manufacture of second resin layer)
Acrylic resin (“Sumipex HT55X” manufactured by Sumitomo Chemical Co., Ltd.) was supplied to a heat-melt extrusion film forming machine equipped with a T-die. The acrylic resin was extruded from the T-die, and the acrylic resin was formed into a film. As a result, a long second resin layer having a thickness of 40 μm formed of acrylic resin was obtained.

(1-3. Laminating)
The surface of the first resin layer was subjected to corona treatment. Then, an ultraviolet curable adhesive (“Arkles KRX-7007” manufactured by ADEKA Corporation) was applied to the corona-treated surface of the first resin layer to form an adhesive layer.

The surface of the second resin layer was treated with corona. Then, an ultraviolet curable adhesive (“Arkles KRX-7007” manufactured by ADEKA Corporation) was applied to the corona-treated surface of the second resin layer to form an adhesive layer.

After that, the first resin layer and the polarizing element layer are bonded via the adhesive, and the second resin layer and the polarizing element layer are bonded via the adhesive, using a pinch roller. , Goed at the same time. Immediately after the bonding, an ultraviolet irradiation device was used to irradiate 750 mJ / cm ² of ultraviolet rays from the temporary substrate side to cure the adhesive. Then, the temporary base material is peeled off to form a long intermediate film having a layer structure of a first resin layer / an adhesive layer (thickness 2 μm) / a polarizing element layer / an adhesive layer (thickness 2 μm) / a second resin layer. Obtained.

An optical pressure-sensitive adhesive sheet (“LUCIACS CS9861US” manufactured by Nitto Denko) having a pressure-sensitive adhesive layer and a light release liner layer was prepared. The light release liner was peeled off, and the adhesive surface of the pressure-sensitive adhesive layer exposed by this peeling was subjected to corona treatment. Further, the surface of the first resin layer of the intermediate film was subjected to corona treatment. After that, the corona-treated surface of the pressure-sensitive adhesive layer and the corona-treated surface of the first resin layer of the intermediate film are pressure-bonded by using a pinch roller to press the pressure-sensitive adhesive layer / first resin layer / adhesive layer / polarizing element layer /. A polarizing film having a layer structure of an adhesive layer / a second resin layer was obtained.
The obtained polarizing film was evaluated by the method described above.

[Examples 2 to 4]
The polarizing film was produced and evaluated by the same method as in Example 1 except that the amount of the reverse plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 1. ..

[Example 5]
A polarizing film was produced and evaluated by the same method as in Example 1 except that the type of the reverse plasticizer was changed to metaterphenyl.

[Examples 6 and 7]
The type of backplasticizer was changed to metaterphenyl. Moreover, the amount of the back plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 1. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Example 8]
The type of backplasticizer was changed to metaterphenyl. Moreover, the amount of the back plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 1. Further, the drying condition of the layer of the resin solution was set to 5 minutes by adding IR irradiation with an IR heater at the same time as hot air drying at 120 ° C. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Example 9]
The type of backplasticizer was changed to metaterphenyl. Moreover, the amount of the back plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 1. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Example 10]
A polarizing film was produced and evaluated by the same method as in Example 1 except that the type of the reverse plasticizer was changed to paraterphenyl.

[Examples 11 to 13]
The type of backplasticizer was changed to paraterphenyl. Moreover, the amount of the back plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 2. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Example 14]
The type of the first polymer was changed to a norbornene-based polymer (“ZEONOR” manufactured by Nippon Zeon Corporation; glass transition temperature 163 ° C.). In addition, the type of reverse plasticizer was changed to metaterphenyl. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Examples 15 to 17]
The type of the first polymer was changed to a norbornene-based polymer (“ZEONOR” manufactured by Nippon Zeon Corporation; glass transition temperature 163 ° C.). In addition, the type of reverse plasticizer was changed to metaterphenyl. Furthermore, the amount of the backplasticizer with respect to the total 100% by weight of the first polymer and the backplasticizer was changed to the value shown in Table 2. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Comparative Example 1]
No backplasticizer was used. That is, the amount of the backplasticizer was changed to 0% by weight with respect to the total of 100% by weight of the first polymer and the backplasticizer. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[Comparative Example 2]
The type of backplasticizer was changed to metaterphenyl. Moreover, the amount of the back plasticizer with respect to the total 100% by weight of the first polymer and the back plasticizer was changed to the value shown in Table 2. Except for the above items, the polarizing film was manufactured and evaluated by the same method as in Example 1.

[result]
The results of the above-mentioned Examples and Comparative Examples are shown in the table below. In the table below, the meanings of the abbreviations are as follows.
In the column of the first polymer, "I": norbornene-based polymer ("ZEONOR" manufactured by Nippon Zeon Corporation; glass transition temperature 138 ° C.).
In the column of the first polymer, "II": norbornene-based polymer ("ZEONOR" manufactured by Nippon Zeon Corporation; glass transition temperature 163 ° C.).
"A" in the column of reverse plasticizer: orthoterphenyl.
"B" in the column of reverse plasticizer: metaterphenyl.
In the column of reverse plasticizer, "C": Paraterphenyl Water vapor permeability: Water vapor permeability per 100 μm thickness of the sample resin obtained by heating the first resin to 250 ° C.
Re: In-plane lettering of the first resin layer.
Rth: Lettering in the thickness direction of the first resin layer.
Content double amount: Amount of solvent contained in the first resin.

100 Polarizing film 110 First resin layer 120 Polarizer layer 130 Second resin layer 200 Polarizing film 210 First adhesive layer 220 Second adhesive layer 230 Adhesive layer 240 λ / 4 layer

Claims

The first resin layer, the polarizing element layer and the second resin layer are provided in this order.
At least one of the first resin layer and the second resin layer is a specific resin layer formed of a specific thermoplastic resin containing a polymer and a back plasticizer.
The amount of the reverse plasticizer is 0.5% by weight or more and 23% by weight or less with respect to 100% by weight of the specific thermoplastic resin.
The water vapor transmittance per 100 μm thickness of the first sample resin obtained by heating the specific thermoplastic resin to 250 ° C. is 4 g / (m 2 · day) or less.
A polarizing film satisfying the following formula (1).
CTE (I) / CTE (II) <1 (1)
(In equation (1)
CTE (I) represents the average linear expansion coefficient of the first sample resin at 70 ° C to 85 ° C.
CTE (II) represents the average linear expansion coefficient of the second sample resin obtained by heating a contrasting resin having a composition obtained by removing the backplasticizer from the specific thermoplastic resin to 250 ° C. at 70 ° C. to 85 ° C. .. )
The polarizing film according to claim 1, wherein a first adhesive layer is provided between the first resin layer and the polarizing element layer.
The polarizing film according to claim 1 or 2, wherein a second adhesive layer is provided between the polarizing element layer and the second resin layer.
The in-plane retardation of the specific resin layer at a measurement wavelength of 550 nm is 5 nm or less.
The polarizing film according to any one of claims 1 to 3, wherein the retardation of the specific resin layer in the thickness direction at a measurement wavelength of 550 nm is -5 nm or more and 5 nm or less.
The polarizing film according to any one of claims 1 to 4, wherein the specific thermoplastic resin contains a polymer containing an alicyclic structure.
The polarizing film according to any one of claims 1 to 5, wherein the specific resin layer has a thickness of 9 μm or less.
The polarizing film according to any one of claims 1 to 6, wherein the polarizing element layer has a thickness of 19 μm or less.
The polarizing film according to any one of claims 1 to 7, wherein the specific thermoplastic resin contains 0.010% by weight or more and 10.0% by weight or less of a solvent.
The polarizing film according to any one of claims 1 to 8, wherein the reverse plasticizer is a terphenyl compound.
The polarizing film according to any one of claims 1 to 9, further comprising a pressure-sensitive adhesive layer, the first resin layer, the polarizing element layer, and the second resin layer in this order.
The polarizing film according to claim 10, further comprising a λ / 4 layer between the pressure-sensitive adhesive layer and the first resin layer.
The method for manufacturing a polarizing film according to any one of claims 1 to 11.
A step of applying a resin solution containing a polymer, a reverse plasticizer and a solvent on a temporary substrate, and
A step of drying the resin liquid to obtain a specific resin layer formed of the specific thermoplastic resin, and a step of obtaining the specific resin layer.
The step of bonding the specific resin layer and the polarizing element layer, and
A method for producing a polarizing film, comprising the step of peeling off the temporary substrate in this order.
The method for producing a polarizing film according to claim 12, which comprises a step of forming a pressure-sensitive adhesive layer.
A display device comprising a display body and the polarizing film according to any one of claims 1 to 11.
A display device in which the polarizing film includes a first resin layer, a polarizing element layer, and a second resin layer in this order from the display body side.
The display device according to claim 14, wherein the display body is a liquid crystal panel.
The display device according to claim 14, wherein the display body is an organic electroluminescence panel.