KR102392232B1 - Polarizing plate for curved image display panel - Google Patents

Abstract

[Problem] An object of the present invention is to provide a polarizing plate for a curved image display panel capable of suppressing peeling and lifting from a curved display panel even by long-term use and/or use in a high-temperature environment.
[Solutions] A polarizing plate used for a curved image display panel having an average radius of curvature R and a thickness H, the polarizing plate having a horizontal length L1 in a planar state,
Polarizing plate thickness H1 used as a concave surface side when it is pasted together by a curved image display panel is following formula (1):
L1(H + H1)/2R ≤ 0.4 (1)
A polarizing plate that satisfies

Description

Polarizing plate for curved image display panel {POLARIZING PLATE FOR CURVED IMAGE DISPLAY PANEL}

The present invention relates to a polarizing plate used for a curved image display panel, and a curved image display panel including the same.

Conventionally, as a polarizing plate used in various image display panels such as liquid crystal display panels and organic electroluminescence (organic EL) display panels, dichroic dyes such as iodine or dichroic dyes are oriented and adsorbed to polyvinyl alcohol-based resin films. The polarizing plate which has the structure which laminated|stacked the protective film like a triacetyl cellulose film on the single side|surface or both surfaces of the used polarizing film via an adhesive layer is known (for example, patent documents 1-3). Such a polarizing plate is a form in which various optical layers such as a retardation film or an optical compensation film are further laminated as needed, and is bonded to an image display element such as a liquid crystal cell or an organic EL display element to form an image display panel make up

Japanese Patent Laid-Open No. 2010-211196 Japanese Laid-Open Patent Publication No. 10-062624 Japanese Patent Laid-Open No. Hei 07-134212

In recent years, examination regarding the image display apparatus of various shapes is made|formed from a viewpoint of designability. Among them, since the difference between the distance from the viewer to the center of the screen and the side edges is small, and a feeling of immersion on the screen is obtained, interest in curved image display devices such as curved liquid crystal televisions is increasing, and various Product development is in progress.

Also in a curved image display device, although it is necessary to use a polarizing plate similarly to a flat image display device, in order to manufacture a curved image display device, when the conventional polarizing plate disclosed in the said patent documents 1 - 3 is used for a curved display panel, time Peeling or lifting of the polarizing plate from the curved display panel may occur over time. In a curved display panel, peeling and lifting of a polarizing plate are especially easy to generate|occur|produce on the concave surface side (viewing side), and it leads to the display defect in a visual recognition area|region. Moreover, peeling of a polarizing plate from a curved-surface display panel and generation|occurrence|production of a float become especially remarkable in a high-temperature environment. For this reason, when exposed to the heat of a light source for a long period of time due to long-term use, etc., or when transporting which tends to become a high-temperature and high-humidity environment, and depending on an area of use, there is a possibility that more serious peeling or lifting may be caused.

Therefore, the present invention solves the above problems that can occur uniquely in a polarizing plate used for a curved image display panel, and peels off or floats from the curved display panel even by long-term use and/or use in a high-temperature environment. It aims at providing the polarizing plate for curved image display panels which can be suppressed.

The present invention provides the following preferred aspects [1] to [8].

[1] A polarizing plate used for a curved image display panel having an average radius of curvature R (mm) and a thickness H (mm), the polarizing plate having a horizontal length of L1 (mm) in a planar state,

Polarizing plate thickness H1 (mm) used as a concave surface side when it is pasted together by a curved image display panel is following formula (1):

L1(H + H1)/2R ≤ 0.4 (1)

A polarizing plate that satisfies

[2] The polarizing plate according to the above [1], wherein the thickness H of the curved image display panel is 0.4 mm or more.

[3] The polarizing plate according to [1] or [2], wherein the rate of dimensional change after 250 hours under 80°C drying is 3% or less.

[4] The polarizing plate according to any one of [1] to [3], wherein the polarizing film in the polarizing plate is a stretched and dyed polyvinyl alcohol film.

[5] The polarizing plate according to any one of [1] to [4], wherein the curved image display panel has an average radius of curvature R of 900 to 7000 mm.

[6] The polarizing plate according to any one of [1] to [5], wherein the horizontal length L1 of the polarizing plate in a planar state is 500 mm or more.

[7] A curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate is the polarizing plate according to any one of [1] to [6] above.

[8] A curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate and the convex-side polarizing plate are the polarizing plates according to any one of [1] to [6] above.

ADVANTAGE OF THE INVENTION According to this invention, the polarizing plate for curved image display panels which can suppress peeling from the display panel of a curved state even by long-term use and/or use in a high-temperature environment can be provided.

1 is a schematic diagram of a curved image display panel for explaining an average radius of curvature;
2 is a cross-sectional view of an image display panel in a curved state including a polarizing plate.
3 is a cross-sectional view showing a configuration of a polarizing plate and a configuration that is an embodiment of a curved image display panel.
4 : shows an example of the absorption axis direction of the polarizing plate in a curved image display apparatus.
5 : shows an example of the absorption axis direction of the polarizing plate in a curved image display apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

In addition, in this invention, a "planar state" means the state which is flat as a whole without a curved part. In addition, a "curved state" generally means a state in which the whole is curved by one arc, and a case in which a curved surface is formed as a whole including a curved portion by one or a plurality of arcs. In the present invention, the "average radius of curvature" is an average value of the radius of curvature at three points of the left and right ends and the central portion of the image display panel. That is, in FIG. 1 , the average radius of curvature _is a value calculated by (R _left + R + R _right )/3.

The present invention relates to a polarizing plate used for a curved image display panel having an average radius of curvature R (mm) and a thickness H (mm). The polarizing plate of the present invention has a horizontal length of L1 (mm) in a planar state, and the thickness H1 (mm) of the polarizing plate used on the concave side when bonded to the curved image display panel is expressed by the following formula (1):

L1(H + H1)/2R ≤ 0.4 (1)

is satisfied with In addition, in this invention, the concave surface side shows the side corresponding to the visual recognition side of a curved image display panel, and the convex surface side means the side opposite with respect to the concave surface side.

Here, the horizontal direction length in a planar state has the same horizontal direction length on the image display panel of L1 and thickness H, and the polarizing plate which has thickness H1 is pasted together, and average radius of curvature R (here R is to the center of panel thickness) (defined as the radius of )), the length of the center part of the panel does not change because it is a reference. On the other hand, the horizontal length (defined as the length of the central position of the thickness of the polarizing plate) of the polarizing plate after being curved is calculated as the length of the arc of the radius of curvature {R - (H + H1) / 2}. The inventors have found that the change from L1 to this length becomes important for solving the problem of the present invention. From this, in the present invention, the following formula which is the above change amount:

L1 - L1{R - (H + H1)/2}/R = L1(H + H1)/2R

It is important in order to suppress peeling and lifting of a polarizing plate to suppress low, that is, to set it as 0.4 or less.

The value of L1(H+H1)/2R in Formula (1) is 0.40 or less, 0.38 or less is preferable, 0.35 or less is more preferable, and 0.30 or less is still more preferable. If the value of L1(H+H1)/2R in the formula (1) is below the upper limit, peeling and lifting of the polarizing plate from the image display panel in a curved state even after long-term use or use in a high-temperature environment is further difficult to occur In addition, the value of L1(H+H1)/2R in Formula (1) is 0.01 or more normally.

A curved image display panel is normally not curved in the vertical direction (up and down direction), but is curved so that the viewer side becomes a concave surface and the opposite side (backlight unit, etc. side) becomes a convex surface in the horizontal direction (left and right direction). It is a shape constituting a part of a cylinder whose central axis is in a vertical direction (up and down direction).

A curved image display panel becomes like this. Preferably it is 0.4 mm or more, More preferably, it is 0.8 mm or more, More preferably, it has the thickness H of 1.0 mm or more. When the thickness H of a curved image display panel is more than the said lower limit, various materials can be used as a member used for a curved image display panel, and since handling becomes easy even when a display panel is enlarged, it is industrially advantageous. In addition, the thickness H of a curved image display panel is 2.0 mm or less normally.

The curved image display panel has an average radius of curvature R of preferably 7000 mm or less, more preferably 6600 mm or less, still more preferably 5000 mm or less, still more preferably 4000 mm or less, particularly preferably 3000 mm or less. has A curved image display panel has an average radius of curvature R of 300 mm or more, for example, Preferably it is 900 mm or more, More preferably, it is 1000 mm or more, More preferably, it is 1200 mm or more. A curved image display panel becomes like this. Preferably it is 900-7000 mm, More preferably, it has an average radius of curvature R of 1000-6600 mm. When the average radius of curvature R of the curved image display panel is equal to or less than the upper limit, the difference between the distance from the viewer to the center of the screen and the edge of the screen is smaller, so that a sense of immersion in the screen can be further obtained. When the average radius of curvature R of the curved image display panel is equal to or greater than the lower limit, peeling and lifting of the polarizing plate from the curved image display panel due to long-term use or use in a high-temperature environment is further suppressed.

The average radius of curvature R of the curved image display panel also varies depending on the equipment used. For example, in the case of a device having a small display such as a personal computer or a mobile device, the average radius of curvature R is often smaller (larger curvature). Also, there are cases in which an apparatus having a large display such as a curved display television is also made to have a smaller average radius of curvature R to further enhance a sense of immersion. Since the polarizing plate of the present invention is excellent in the effect of suppressing peeling and lifting of the polarizing plate from the display panel even when used for a long period of time and/or in a high-temperature environment in a state where the average radius of curvature R is small, for example, 900 to 7000 mm, especially 900-5000 mm, Furthermore, it can use for the curved-surface image display panel which has an average radius of curvature R of 1000-4000 mm.

As for the polarizing plate of this invention, the horizontal direction length L1 in a planar state becomes like this. Preferably it is 500 mm or more, More preferably, it is 700 mm or more, More preferably, it is 1100 mm or more, More preferably, it is 1400 mm or more. If the horizontal length L1 in the planar state of the polarizing plate of the present invention is equal to or greater than the lower limit, the horizontal length of the applicable curved image display panel increases, so that a sense of immersion in the screen can be further obtained. Moreover, as for the polarizing plate of this invention, the horizontal direction length L1 in a planar state is 2500 mm or less normally. In addition, the horizontal direction of a polarizing plate coincides with the horizontal direction of the curved image display device containing a curved image display panel, and the vertical direction of a polarizing plate is a direction orthogonal to the said horizontal direction. The vertical length in the planar state of the polarizing plate of the present invention is determined by the horizontal length L1 and the aspect ratio of the curved image display panel.

In the case of using a conventional polarizing plate for manufacturing a curved image display panel, even in a room temperature environment, in the case of long-term use, the risk of peeling or lifting of the polarizing plate from the curved image display panel increases, and the lighting for a long time However, by use in a high-temperature environment, peeling of the polarizing plate from the image display panel of a curved surface state, and generation|occurrence|production of a float are further encouraged. Although this reason is not bound by a specific theory, it is thought that it originates in the deformation|transformation and compressive stress of the horizontal direction which generate|occur|produces when a polarizing plate is curved. In order to suppress this deformation/compressive stress, changing the thickness H1 of the polarizing plate according to the average radius of curvature R, the thickness H, and the horizontal length L1 of the curved image display panel is to change the thickness H1 of the polarizing plate from the image display panel in a curved state. It is thought to be effective in suppressing lifting. In this invention, suppression of peeling and floating of a polarizing plate is achieved by determining the thickness H1 of a polarizing plate so that said Formula (1) may be satisfied.

As for the polarizing plate of this invention, the dimensional change rate after 250 hours under 80 degreeC drying becomes like this. Preferably it is 3.0 % or less, More preferably, it is 2.0 % or less, More preferably, it is 1.5 % or less. When the dimensional change rate of the polarizing plate is equal to or less than the upper limit, it is possible to suppress contraction and/or expansion of the polarizing plate under long-term use or high-temperature environments, so that peeling or lifting of the polarizing plate from the image display panel in a curved state is more difficult to occur. lose Moreover, the said dimensional change rate of a polarizing plate is 0 % or more normally.

The rate of dimensional change is controllable by suppressing the dimensional change of the polarizing film that contributes to the shrinkage and expansion of the polarizing plate. The dimensional change of a polarizing film is controllable, for example by changing manufacturing conditions, such as a draw ratio of a polarizing film, and a kind, or by making the rigidity of the protective layer adjacent to a polarizing film high. Specifically, the dimensional change can be controlled by setting the draw ratio to be preferably 8 times or less, more preferably 7.5 times or less, and still more preferably 7 times or less.

In addition, a dimensional change rate is computable by cutting a polarizing plate to 100 mm x 100 mm size, measuring and comparing the initial dimension and the dimension after 250 hours under 80 degreeC drying, without bonding to glass. Naturally, the dimensional change rate at the time of bonding together to glass through an adhesive becomes smaller than the dimensional change rate in the glass non-bonding mentioned above. Moreover, although it changes with the kind of adhesive, the dimensional change rate in glass non-bonding is about 1/2 - 1/15 normally.

The polarizing plate of the present invention is not limited in its configuration as long as it is configured to have a function normally possessed as a polarizing plate. For example, in a preferred embodiment, an adhesive is applied on one side or both sides of the polarizing film A protective layer laminated therebetween, an adhesive layer for bonding to an image display element, and an optical layer in some cases are included.

In one embodiment of the present invention, the polarizing plate is composed of a protective layer, a polarizing film, a protective layer and an adhesive layer, and optionally an optical layer. Here, the polarizing film and the protective layer are laminated through an adhesive.

When the structure in one Embodiment of the polarizing plate of this invention and a curved image display panel is demonstrated based on FIG. 3, the polarizing plate of this invention is the adhesive layer 10 in order from the layer adjacent to the image display element 3 , a protective layer 11 , a polarizing film 12 , a protective layer 11 , and optionally an optical layer (not shown) are laminated. Moreover, normally, the polarizing film 12 and the protective layer 11 are laminated|stacked via an adhesive agent. Moreover, the curved image display panel of this invention is the image display element 3 and the concave-surface side polarizing plate 1 respectively bonded to the image display element 3 via the adhesive layer 10 in one Embodiment of this invention. ) and a convex-side polarizing plate (2). In one embodiment of the present invention, the concave-side polarizing plate (1) comprises an adhesive layer (10), a protective layer (11), a polarizing film (12), a protective layer ( 11) and optionally a surface treatment layer 13 and/or an optical layer, and the convex-surface-side polarizing plate 2 is sequentially configured from the layer adjacent to the image display element 3 to the adhesive layer 10 and the protective layer. (11), a polarizing film (12), a protective layer (11), and an optical layer as needed.

Hereinafter, each component of the polarizing plate of this invention is demonstrated in detail.

<Adhesive layer>

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, a conventionally known pressure-sensitive adhesive can be used without particular limitation, for example, a pressure-sensitive adhesive having a base polymer such as acrylic, rubber, urethane, silicone, polyvinyl ether, and the like can be used. Moreover, an energy ray-curable adhesive, a thermosetting adhesive, etc. may be sufficient. Among these, the adhesive which used the acrylic resin excellent in transparency, adhesive force, rework property, weather resistance, heat resistance, etc. as a base polymer is preferable.

Although it does not specifically limit as an acrylic adhesive, (meth)acrylic acid ester-type base polymers, such as (meth)butyl acrylate, (meth)ethyl acrylate, (meth)acrylate isooctyl, (meth)acrylic acid 2-ethylhexyl, A copolymer-based base polymer containing two or more types of (meth)acrylic acid esters and the like is preferably used. In addition, a polar monomer is copolymerized in these base polymers. As the polar monomer, for example, (meth)acrylic acid, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylamide, 2-N,N-dimethylaminoethyl (meth) ) A monomer having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as acrylate and glycidyl (meth)acrylate, is mentioned.

Although these acrylic adhesives can also be used independently, they are used together with a crosslinking agent normally. Examples of the crosslinking agent include divalent or polyvalent metal ions that form a metal carboxylate salt between carboxyl groups, polyamine compounds, and amide bonds between carboxyl groups, polyepoxy compounds or polyol compounds, What forms an ester bond between a carboxyl group, it is a polyisocyanate compound, and what forms an amide bond between a carboxyl group etc. are illustrated. Among them, polyisocyanate compounds are widely used.

An energy ray-curable adhesive has a property of being cured by irradiation with energy rays such as ultraviolet rays or electron beams, has adhesiveness even before energy ray irradiation, and adheres to an adherend such as a film, and cures by irradiation with energy rays to adjust the adhesion It is a pressure-sensitive adhesive having the property of being able to As the energy ray-curable pressure-sensitive adhesive, it is particularly preferable to use an ultraviolet-curable pressure-sensitive adhesive. An energy-beam-curable adhesive generally consists of an acrylic adhesive and an energy-beam polymeric compound as main components. Usually, a crosslinking agent is further mix|blended, and a photoinitiator, a photosensitizer, etc. can also be mix|blended as needed.

The pressure-sensitive adhesive layer, in addition to the base polymer and the crosslinking agent, if necessary, to adjust the adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. of the pressure-sensitive adhesive, for example, natural or synthetic resins, tackifying resins, antioxidants, You may contain additives, such as an antistatic agent, a ultraviolet absorber, dye, a pigment, an antifoamer, a corrosive, a photoinitiator, and a thermal polymerization initiator. Moreover, it can also be set as the adhesive layer which contains microparticles|fine-particles and shows light-scattering property. Examples of the ultraviolet absorber include a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, and a nickel complex salt compound.

In the present invention, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer preferably contains a silane compound, and particularly preferably contains the silane compound in the acrylic resin before adding the crosslinking agent. Since the silane-based compound improves adhesion to glass, the inclusion of the silane-based compound improves the adhesion between the image display element sandwiched between the glass substrate and the pressure-sensitive adhesive layer, so that high adhesion to the display panel can be secured, so that a long-term and / Alternatively, peeling or floating from the curved display panel is less likely to occur even when used in a high-temperature environment.

The pressure-sensitive adhesive layer is, for example, the above-mentioned pressure-sensitive adhesive as an organic solvent solution, applied on a film or layer (eg, polarizing film, etc.) to be laminated by a die coater or a gravure coater, etc., and dried can be formed by Moreover, it can form also by the method of transferring the sheet-like adhesive formed on the plastic film (referred to as a separate film) to which the release process was given to the film or layer to be laminated|stacked. Although there is no restriction|limiting in particular about the thickness of an adhesive layer, It is preferable to exist in the range of 2-40 micrometers, It is more preferable to exist in the range of 5-35 micrometers, It is more preferable to exist in the range of 10-30 micrometers. When the thickness of an adhesive layer is more than the said lower limit, generation|occurrence|production of peeling and lifting by long-term use and/or use in a high-temperature environment can further be suppressed. If the thickness of the adhesive layer is less than or equal to the upper limit, the increase in the thickness of the polarizing plate is suppressed, and as a result, the adhesive layer is difficult to deform in a curved state. can Thereby, deterioration of the display function in the frame periphery of the image display device can be suppressed.

In a preferred embodiment, the adhesive layer of the polarizing plate of the present invention comprises an acrylic resin which is a copolymer of butyl acrylate, methyl acrylate, 2-phenoxyethyl acrylate, 2-hydroxyethyl acrylate and acrylic acid, a silane compound, and isocyanate as a crosslinking agent. composed of compounds.

In a preferred embodiment, the polarizing plate of the present invention includes an adhesive layer. Adhesive force to glass (hereinafter, may be referred to as “adhesive force to glass (flat, 23°C)”) of the adhesive layer measured in a planar state at 23°C and 50%RH is preferably 1.0 It is N/25 mm or more, More preferably, it is 2.0 N/25 mm or more. If the adhesive force of the adhesive layer to the glass (flat surface, 23 ℃) is 1.0 N/25 mm or more, long-term continuous use, long-term and/or high-temperature environment use, movement and storage, etc., of the polarizing plate from the curved image display panel Peeling and floating can be suppressed more effectively. Polarizing plate of this invention WHEREIN: Adhesive force with respect to glass (plane, 23 degreeC) becomes like this. More preferably, it is 3.0 N/25 mm or more, Especially preferably, it is 4.0 N/25 mm or more.

Moreover, in the polarizing plate of this invention, the adhesive force with respect to the glass of the adhesive layer measured in a curved state (Hereinafter, it may describe as "adhesive force to glass (curved surface, 23 degreeC)"), 1.5 N/25 mm or more , and more preferably 2.5 N/25 mm or more. The adhesive force (curved surface, 23 degreeC) with respect to glass of the polarizing plate of this invention becomes like this. More preferably, it is 3.5 N/25 mm or more, More preferably, it is 4.5 N/25 mm or more. The adhesive force to glass measured in a curved state does not necessarily become the same as the adhesive force to glass measured in a planar state, and does not change with certain laws, such as a simple proportional relationship. Since the polarizing plate of the present invention is used for a curved image display device, controlling the adhesive force to the glass in the curved state to be within a certain range is only the adhesive force to the glass in the planar state by the adhesive force of the polarizing plate to the glass It leads to control of the adhesive force with respect to the image display element of a polarizing plate in the state based on actual use more compared with the case of controlling. In particular, if the adhesive force to glass (curved surface, 23 ° C.) is 1.5 N/25 mm or more, and further 2.5 N/25 mm or more, after the polarizing plate is mounted on the curved image display panel, during long-term use or long-term use, the light source Sufficient adhesion to the image display panel can be ensured even under harsh environments such as when exposed to heat or during transportation in a high temperature and high humidity environment, so that peeling or lifting of the polarizing plate from the image display panel in a curved state does not occur. it gets difficult

From the viewpoint of sufficiently securing the adhesion to the image display panel in a long-term and/or high-temperature environment, the adhesive force to the glass (flat surface, 23 ° C.) and the adhesive force to the glass (curved surface, 23 ° C.) of the polarizing plate of the present invention are both It is preferable that it is 2.0 N/25 mm or more, It is preferable that it is 3.0 N/25 mm or more, It is especially preferable that it is 4.0 N/25 mm or more.

On the other hand, in the manufacturing process of a curved image display panel, when a bonding error occurs when bonding a polarizing plate to an image display element or after bonding, similarly to the manufacturing process of a conventional flat image display panel, rework in a planar state (that is, It may be peeled off to reuse the panel), but rework in a curved state is also conceivable. When reworked in a curved state, in addition to the compressive stress already applied by being in a curved state, in order to peel a polarizing plate from an image display panel, a compressive stress is additionally applied. For this reason, in rework in a curved state, peeling of the polarizing plate from a curved image display panel tends to be technically difficult compared to rework in a flat state, and in particular, the higher the adhesive force of the polarizing plate, the higher the load to peel the polarizing plate. Since compressive stress becomes large, it becomes easy to produce defects, such as the glass plate which comprises a display panel being broken, at the time of peeling, for example.

If the adhesive force to the glass is too high, lifting or peeling of the polarizing plate itself cannot occur from the image display panel, but there is a possibility that a problem in reworkability as described above may occur. It is preferable that the adhesive force to glass (flat surface, 23° C.) is 20.0 N/25 mm or less, more preferably 15.0 N/25 mm or less, still more preferably 10.0 N/25 mm or less, particularly preferably 6.0 N/25 mm or less. 25 mm or less. Moreover, the adhesive force to glass (curved surface, 23 degreeC) becomes like this. Preferably it is 20.0 N/25 mm or less, More preferably, it is 15.0 N/25 mm or less, More preferably, it is 10.0 N/25 mm or less, Especially Preferably it is 6.0 N/25 mm or less.

When the upper limit of the adhesive force with respect to each said glass is in the said range, in the manufacturing process of a curved image display panel, when a bonding error of a polarizing plate generate|occur|produces or is discovered, it becomes easy to rework a polarizing plate from a display panel easily. From the viewpoint of reworkability, in the present invention, it is preferable that both the adhesive force to glass (flat surface, 23°C) and the adhesive force to glass (curved surface, 23°C) are 20.0 N/25 mm or less.

When the polarizing plate of the present invention includes an adhesive layer, the adhesive force to glass (flat, 23°C) is 20.0 N/25 mm or less, further 15.0 N/25 mm or less, particularly 10.0 N/25 mm, particularly 6.0 Even if it is N/25 mm or less, especially 4.0 N/25 mm or less, since Formula (1) is satisfied, float and peeling can be suppressed.

The adhesive force (flat, 23 degreeC) with respect to the said glass affixes the polarizing plate cut|disconnected to the predetermined size to the flat glass substrate through the adhesive layer, autoclave process, 23 degreeC, 50%RH It is a value measured by peeling a polarizing plate at a predetermined speed|rate in a 180 degree direction from a glass substrate after leaving still for 24 hours below. Adhesive force to glass (curved surface, 23 ° C.) is similar to the method for measuring adhesion to glass (flat surface, 23 ° C.), and a test piece in which a polarizing plate is bonded to a glass plate is placed on a metal plate processed with a radius of curvature of 2500 mm. It is a value measured by peeling a polarizing plate after leaving still for 24 hours under 23 degreeC and 50 %RH in the state which made it so and fixed.

A more detailed measurement method of the adhesive force to glass (flat surface, 23° C.) and the adhesive force to glass (curved surface, 23° C.) is as described in Examples to be described later.

In the polarizing plate of the present invention, after 250 hours under 80 ° C. dry, the adhesive force of the adhesive layer to the glass measured in a planar state (hereinafter referred to as “adhesive force to glass (flat, 80 ° C.)” may be described) It is preferable that silver is 7.0 N/25 mm or more, It is more preferable that it is 9.0 N/25 mm or more, It is more preferable that it is 11.0 N/25 mm or more. In addition, in the polarizing plate of the present invention, after 250 hours under 80 ° C. dry, the adhesive force of the adhesive layer measured in a curved state to glass (hereinafter referred to as “adhesive force to glass (curved surface, 80 ° C.)” ), it is preferable that it is 8.0 N/25 mm or more, It is more preferable that it is 10.0 N/25 mm or more, It is more preferable that it is 12.0 N/25 mm or more. In addition, the test piece may break at the time of measurement due to the increase in adhesive force, and the adhesive force to each glass measured after 250 hours at 80° C. may not be measured as a numerical value, which is a particularly preferred aspect of the present invention.

When the adhesive force to each glass measured after 250 hours at 80 ° C. is the same as the above, sufficient adhesion to the display panel can be secured even for a long period of time and/or use in a high-temperature environment, etc., from the curved display panel It becomes difficult to cause peeling or lifting of the skin. In the polarizing plate having the above-mentioned adhesive force to glass in a certain range (flat, 23 ° C.), it is particularly advantageous for the polarizing plate of the present invention that the adhesive force to each glass measured after 250 hours at 80 ° C. is the same as the above value. Do.

The adhesive force to glass (flat, 80°C) is preferably 5.0 N/25 mm or more higher than the adhesive force to glass (flat, 23°C), more preferably 7.0 N/25 mm or more higher, and 10.0 N/25 Those higher than mm are particularly preferred. In addition, the adhesive force to glass (curved surface, 80 ° C.) is preferably 5.0 N/25 mm or more higher than the adhesive force to glass (curved surface, 23 ° C), more preferably 7.0 N/25 mm or more higher, more preferably 10.0 N It is particularly preferable to be higher than /25 mm. In the polarizing plate having the above-mentioned adhesive force to glass in a certain range (flat, 23°C), the adhesive force to each glass measured after 250 hours under 80°C dry is 23°C, each glass measured under 50%RH When it is 5.0 N/25 mm or more higher than the adhesive force to an image display element, in the initial state of bonding after bonding to an image display element, in order to bond to an image display element and use it in normal temperature to low-temperature environment, while ensuring the adhesive force required, rework easily it becomes possible to In addition, sufficient adhesion to the display panel can be ensured when exposed to the heat of a light source for a long period of time, when transported in a high-temperature and high-humidity environment, and when used for a long period of time and/or in a high-temperature environment. It becomes difficult to produce peeling and lifting.

The difference between the adhesive force to glass (flat surface, 80 ° C.) and the adhesive force to glass (flat surface, 23 ° C.), and the difference between the adhesion force to glass (curved surface, 80 ° C) and the adhesive force to glass (curved surface, 23 ° C.) , The upper limit is not particularly limited, but is usually 20.0 N/25 mm or less.

The adhesive force to glass (curved surface, 80 ° C.) is preferably 5.0 N/25 mm or more higher than the adhesive force to glass (flat surface, 23 ° C.), more preferably 7.0 N/25 mm or more higher, more preferably 10.0 N/25 Those higher than mm are particularly preferred. If the difference between the adhesive force to glass (curved surface, 80°C) and the adhesive force to glass (flat surface, 23°C) is within the above range, bonding and rework in a flat state are easy, and long-term and/or high-temperature environment after being curved Also in use, etc., sufficient adhesive force with respect to a display panel can be ensured and peeling from a curved display panel or a float becomes difficult to produce.

The adhesive force to the glass (flat surface, 80 ° C.) and the adhesive force to the glass (curved surface, 80 ° C.) are the adhesive force to the glass described above (flat surface, 23 ℃) and adhesion to glass (curved surface, 23 ℃) measured by the same method.

Since the adhesive force of the adhesive layer to glass varies depending on the type of component constituting the adhesive layer, its content ratio, forming conditions (drying, active energy ray irradiation conditions), thickness after formation, etc., the desired adhesive strength to glass What is necessary is just to select suitably the structural component of an adhesive layer, content ratio, formation conditions, thickness, etc. according to it. Specifically, for example, by using an acrylic resin as a component of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, blending a silane-based compound, and thickening the layer thickness of the pressure-sensitive adhesive layer, the adhesive force of the pressure-sensitive adhesive layer to glass can be made higher Moreover, the adhesive force with respect to glass can be controlled to a desired value by changing the kind, its ratio, the kind, and its content of a silane-type compound of the monomer which comprises an acrylic resin.

<polarizing film>

As a polarizing film that can constitute the polarizing plate of the present invention, it is a film having a function of extracting linearly polarized light from incident natural light, for example, a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented can be used. . As polyvinyl alcohol-type resin which comprises a polyvinyl alcohol-type resin film, what saponified polyvinyl acetate-type resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith (eg, ethylene-vinyl acetate copolymer, etc.). Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of polyvinyl alcohol-type resin is 85-100 mol% normally, and 98 mol% or more is preferable. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal, polyvinyl acetal, and polyvinyl butyral modified with aldehydes can be used. The polymerization degree of polyvinyl alcohol-type resin is 1000-10000 normally, and 1500-5000 are preferable.

What formed such a polyvinyl alcohol-type resin into a film can be used as a raw film of a polarizing film. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, A film can be formed by a conventionally well-known method. Although the film thickness of the raw film which consists of polyvinyl alcohol-type resin is not specifically limited, Considering the ease of extending|stretching, it is, for example, 10-150 micrometers, Preferably it is 15-100 micrometers, More preferably, it is 20- 80 μm.

A polarizing film is a process of uniaxially stretching a polyvinyl alcohol-type resin film, such as such a polyvinyl alcohol film, normally, a process of adsorbing a dichroic dye by dyeing a polyvinyl alcohol-type resin film with a dichroic dye, a dichroic dye It is manufactured through a process of treating the polyvinyl alcohol-based resin film adsorbed with an aqueous boric acid solution, and a process of washing with water after treatment with an aqueous boric acid solution. It is preferable from an industrial viewpoint to use the extending|stretching and dyeing|dye polyvinyl alcohol film manufactured by this as a polarizing film. In addition, the stretched and dyed polyvinyl alcohol film is a (adsorbed) stretched polyvinyl alcohol film containing a dichroic dye, and the draw ratio is as follows.

Uniaxial stretching of a polyvinyl alcohol-type resin film may be performed before dyeing of a dichroic dye, may be performed simultaneously with dyeing|staining, or may be implemented after dyeing. When performing uniaxial stretching after dyeing|staining, this uniaxial stretching may be implemented before a boric-acid process, and may be implemented during a boric-acid process. Uniaxial stretching can also be implemented in these several steps. In the case of uniaxial stretching, you may extend|stretch uniaxially between the rolls from which circumferential speed differs, and you may extend|stretch uniaxially using a hot roll. In addition, uniaxial stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which the polyvinyl alcohol-based resin film is swelled using a solvent. From a viewpoint of suppressing distortion of a polarizing film, a draw ratio becomes like this. Preferably it is 8 times or less, More preferably, it is 7.5 times or less, More preferably, it is 7 times or less. Moreover, a draw ratio is 4.5 times or more normally from a viewpoint of expressing the function as a polarizing film.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye is mentioned, for example. As a dichroic dye, iodine or a dichroic dye is used, for example. The dichroic dye includes, for example, a dichroic direct dye composed of a disazo compound such as C.I. DIRECT RED 39, a dichroic direct dye composed of a trisazo, a tetrakisazo compound, and the like. Moreover, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

When using an iodine as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing an iodine and potassium iodide normally is employ|adopted. Content of the iodine in this aqueous solution is 0.01-1 mass part per 100 mass parts of water normally, content of potassium iodide is 0.5-20 mass parts per 100 mass parts of water normally. When using an iodine as a dichroic dye, the temperature of the aqueous solution used for dyeing is 20-40 degreeC normally, and the immersion time to this aqueous solution (dyeing time) is 20 to 1800 second normally.

When using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing a water-soluble dichroic dye is usually employ|adopted. Content of the dichroic dye in this aqueous solution is 1x10 ^-4 - 10 mass parts normally per 100 mass parts of water, Preferably it is 1x10 ^-3 - 1 mass part, More preferably, it is 1x10 ^-3 . - 1 x 10 ^-2 parts by mass. This aqueous solution may contain inorganic salts, such as sodium sulfate, as a dyeing aid. When using a dichroic dye as a dichroic dye, the temperature of the dye aqueous solution used for dyeing is 20-80 degreeC normally, and the immersion time (dyeing time) to this aqueous solution is 10 to 1800 second normally.

The boric acid treatment after dyeing|dyeing by a dichroic dye can be performed by immersing the dyed polyvinyl alcohol-type resin film in boric-acid containing aqueous solution. The quantity of boric acid in boric-acid containing aqueous solution is 2-15 mass parts normally per 100 mass parts of water, Preferably it is 5-12 mass parts. When using an iodine as a dichroic dye, it is preferable that this boric-acid containing aqueous solution contains potassium iodide. The quantity of potassium iodide in boric-acid containing aqueous solution is 0.1-15 mass parts normally per 100 mass parts of water, Preferably it is 5-12 mass parts. The immersion time to boric-acid containing aqueous solution is 60 to 1200 second normally, Preferably it is 150 to 600 second, More preferably, it is 200 to 400 second. The temperature of boric-acid containing aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC, More preferably, it is 60-80 degreeC.

The polyvinyl alcohol-type resin film after a boric acid process is water washing process normally. The water washing process can be performed by immersing the polyvinyl alcohol-type resin film by which the boric acid process was carried out, for example in water. The temperature of the water in a water washing process is 5-40 degreeC normally, and immersion time is 1-120 second normally. After washing with water, a drying process is performed and a polarizing film is obtained. A drying process can be performed using a hot-air dryer or a far-infrared heater. The temperature of a drying process is 30-100 degreeC normally, Preferably it is 40-95 degreeC, More preferably, it is 50-90 degreeC. The time of a drying process is 60 to 600 second normally, Preferably it is 120 to 600 second.

Thus, to a polyvinyl alcohol-type resin film, uniaxial stretching, dyeing|staining by a dichroic dye, and a boric-acid process are given, and a polarizing film is obtained. The thickness of a polarizing film can be 5-40 micrometers, for example.

Since the coating-type thin film polarizing film has a small rate of dimensional change compared to a polarizing film formed by stretching a conventionally known polyvinyl alcohol-based resin film, by using the coating-type thin film polarizing film, long-term use and/or use in a high-temperature environment The dimensional change of the polarizing plate in can be suppressed. Moreover, it can contribute to thin film formation of a polarizing plate, and it is preferable in this invention. As a coating-type thin film polarizing film, the thing as illustrated by Unexamined-Japanese-Patent No. 2012-58381, Unexamined-Japanese-Patent No. 2013-37115, International Publication 2012/147633, International Publication No. 2014/091921 can be used, for example. .

<Protective layer>

In a preferred aspect, the polarizing plate of the present invention has a protective layer laminated on one side or both sides of the polarizing film. It is preferable that the polarizing plate of this invention has a protective layer at the point which a protective layer contributes to the prevention of shrinkage and expansion|swelling of a polarizing film, and deterioration prevention of a polarizing film by temperature, humidity, an ultraviolet-ray, etc., for example.

As a material for forming the protective layer, it is preferable to have excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, and the like. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene or acrylonitrile styrene copolymer Styrenic polymers, such as (AS resin), and a polycarbonate type polymer are mentioned. In addition, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, polyolefin-based polymer such as ethylene/propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, alcohol Phone-based polymer, polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylenesulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, Epoxy-based polymers or blends of the above polymers are also exemplified as polymers for forming the protective layer. The protective layer may be formed as a cured layer made of a thermosetting resin such as acrylic, urethane, acrylic urethane, epoxy or silicone resin, or ultraviolet curable resin. Among these, those having a hydroxyl group having reactivity with an isocyanate crosslinking agent are preferable, and particularly, a cellulose-based polymer is preferable. Although the thickness in particular of a protective layer is not restrict|limited, It is generally 500 micrometers or less, It is preferable that it is 1-300 micrometers, It is more preferable that it is 5-200 micrometers, It is more preferable that it is 30-100 micrometers. Moreover, the protective layer may be comprised from the transparent protective film etc. which added the optical compensation function. In addition, the thickness of the outer protective layer laminated|stacked on the back side of a polarizing film and the thickness of the inner protective layer laminated|stacked on the visual side of a polarizing film are the same, or it is preferable that an outer protective layer is thicker than an inner protective layer. In this way, especially when heat is applied to the polarizing plate, curling of the outer and inner protective layers is suppressed or curled toward a lower rigidity, so that peeling or lifting from the display panel is less likely to occur. This is particularly preferably applied from the concave surface side.

Since shrinkage|contraction of a polarizing film can be suppressed by raising the rigidity of the protective layer adjacent to a polarizing film, the dimensional change of a polarizing plate can be suppressed by controlling the rigidity of a protective layer. Here, the rigidity refers to the film thickness multiplied by the tensile modulus of the film used for the protective layer at room temperature (23° C.) (hereinafter, the 23° C. elastic modulus), and the tensile modulus under the conditions of 80° C. (the 80° C. elastic modulus) multiplied by the film thickness. is defined as In particular, by increasing the rigidity obtained by multiplying the 80°C elastic modulus by the film thickness, the dimensional change of the polarizing plate in a high-temperature environment can be suppressed. For example, the cellulosic polymer typified by triacetyl cellulose preferably has an elastic modulus of 3000 to 5000 MPa at 23° C. and an elastic modulus at 80° C. in the range of 2000 to 4000 MPa, and the acrylic polymer represented by polymethyl methacrylate is , 23 °C elastic modulus is 2000 to 4000 MPa, 80 °C elastic modulus is preferably in the range of 800 to 2500 MPa, the polyolefin-based polymer having a norbornene structure has a 23 °C elastic modulus of 2000 to 4000 MPa and 80 °C elastic modulus of 1500 It is preferable that it is the range of -3000 MPa.

The surface of the protective layer that is not adhered to the polarizing film may have a surface treatment layer, for example, may have an optical layer such as a hard coat layer, an antireflection layer, an antistick layer, an antiglare layer, or a diffusion layer.

The hard coat layer is for the purpose of preventing the occurrence of scratches on the surface of the polarizing plate, for example, a method of adding a cured film excellent in hardness and slip properties, etc., to the surface of the protective layer by an ultraviolet curable resin such as acrylic or silicone type, etc. can be formed with The antireflection layer aims at preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. Moreover, the anti-sticking layer is for the purpose of preventing close contact with an adjacent layer.

In addition, the antiglare layer is for the purpose of preventing, for example, that external light is reflected on the surface of the polarizing plate and impairing the visibility of transmitted light of the polarizing plate, for example, roughening by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the protective layer by a method such as a chemical conversion method or a method of mixing transparent fine particles. As the fine particles contained for the formation of the surface fine concavo-convex structure, for example, silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, etc. having an average particle diameter of 0.5 to 50 μm. and transparent fine particles such as inorganic fine particles and organic fine particles made of a crosslinked or uncrosslinked polymer. When forming the surface fine concavo-convex structure, content of the microparticles|fine-particles is 2-50 mass parts normally with respect to 100 mass parts of transparent resin which forms surface fine concavo-convex structure, 5-25 mass parts is preferable. The anti-glare layer may also serve as a diffusion layer (vision magnification function, etc.) for diffusing the light transmitted through the polarizing plate to expand the visual field or the like. In addition, the protective layer may contain a well-known additive as needed. Examples of the additive include an ion trapping agent, an antioxidant, a sensitizer, a light stabilizer, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, an antifoaming agent, a dye, an antistatic agent, and an ultraviolet absorber.

The anti-reflection layer, anti-stick layer, diffusion layer, anti-glare layer, etc. can be formed and integrated into the protective layer itself, or can be formed as a separate optical layer and separate from the protective layer.

<Adhesive layer>

A polarizing film and a protective layer are adhere|attached through an adhesive agent normally. The adhesive for adhering the polarizing film and the protective layer is not particularly limited, but from the viewpoint of thinning the adhesive layer to be formed, a water-based one, that is, one in which an adhesive component is dissolved in water, or one in which an adhesive component is dispersed in water can be heard For example, an adhesive including a polyvinyl alcohol-based resin or a urethane resin may be used as an adhesive component. When it has a protective layer on both surfaces of a polarizing film, the adhesive agent used for the adhesion|attachment may be same or different.

When a polyvinyl alcohol-based resin is included as an adhesive component, the polyvinyl alcohol-based resin includes, in addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, and methylol group-modified polyvinyl alcohol. Modified polyvinyl alcohol-based resins such as polyvinyl alcohol and amino group-modified polyvinyl alcohol may be used. Usually, the adhesive agent which uses polyvinyl alcohol-type resin as an adhesive agent component is prepared as aqueous solution of polyvinyl alcohol-type resin. The density|concentration of the polyvinyl alcohol-type resin in an adhesive agent is 1-10 mass parts normally with respect to 100 mass parts of water, Preferably it is 1-5 mass parts.

The adhesive having a polyvinyl alcohol-based resin as an adhesive component preferably contains a curable component such as glyoxal and a water-soluble epoxy resin and/or a crosslinking agent in order to improve adhesiveness. As a water-soluble epoxy resin, for example, epichlorohydrin is reacted with polyamideamine obtained by reaction of polyalkylene polyamines, such as diethylenetriamine and triethylenetetramine, and dicarboxylic acid, such as adipic acid. Polyamide polyamine epoxy resin obtained by making it can be used preferably. Examples of commercially available polyamide polyamine epoxy resins include "Sumirez Resin 650" (manufactured by Sumika Chemtex Co., Ltd.), "Sumirez Resin 675" (manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (Nippon). PMC Co., Ltd. product) etc. are mentioned. The addition amount of these curable components and/or a crosslinking agent (when added together, the total amount) is 1-100 mass parts normally with respect to 100 mass parts of polyvinyl alcohol-type resin, Preferably it is 1-50 mass parts. When the addition amount of the said curable component and/or a crosslinking agent is in the said range, adhesiveness improves and it can form the adhesive bond layer which shows favorable adhesiveness.

Moreover, when a urethane resin is included as an adhesive agent component, it is preferable to use the mixture of a polyester-type ionomer type|mold urethane resin and the compound which has a glycidyloxy group. Here, the polyester-based ionomer type urethane resin is a urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the skeleton. Since such an ionomer type urethane resin is emulsified directly in water without using an emulsifier and becomes an emulsion, it is preferable as a water-based adhesive agent. Polyester ionomer type urethane resin itself is well known, for example, in Japanese Patent Application Laid-Open No. 7-97504, it is described as an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium, In Patent Publication Nos. 2005-70140 and Japanese Unexamined Patent Application Publication No. 2005-208456, a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group is used as an adhesive to a polarizing film made of a polyvinyl alcohol-based resin. The form which bonds a cycloolefin type resin film together is shown.

Application of the adhesive to the polarizing film and/or the protective layer (protective film) bonded thereto can be performed by a known method, for example, a casting method, a Mayer bar coating method, a gravure coating method, A comma coater method, a doctor blade method, a die coat method, a dip coat method, a spray method, etc. can be used. The casting method is a method in which an adhesive is poured and spread on the surface while moving the film as an object to be coated in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between both. After apply|coating an adhesive agent, a polarizing film and the protective layer bonded to this are laminated|stacked, and a film is bonded together with a nip roll etc. between them. The bonding of the film using a nip roll, for example, after applying the adhesive, pressurized with a roll, etc. to spread it evenly, after applying the adhesive, pass it between the rolls and press to spread it, etc. are adopted. can In this case, the material of the roll to be used may just be a metal, rubber, etc. Moreover, when making a film pass between several rolls and spreading it, the same material may be sufficient as a several roll, and a different material may be sufficient as it.

In addition, to the adhesive surface of a polarizing film and a protective layer, in order to improve adhesiveness, you may give surface treatment, such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment, as appropriate. As a saponification process, the method of immersing in the aqueous solution of alkalis, such as sodium hydroxide and potassium hydroxide, is mentioned.

After the said bonding, a polarizing plate can be obtained by drying and hardening an adhesive agent. This drying process is performed by blowing hot air, for example, The temperature exists in the range of 40-100 degreeC normally, Preferably it exists in the range of 60-100 degreeC. Moreover, drying time is 20 to 1200 second normally.

The thickness of the adhesive bond layer formed with the adhesive agent after drying is 0.001-5 micrometers normally, Preferably it is 0.01-2 micrometers, More preferably, it is 0.01-1 micrometer. When the thickness of an adhesive bond layer exists in the said range, sufficient adhesiveness can be ensured, and since it is preferable also externally, and can contribute to thinning of a polarizing plate, it is preferable for the polarizing plate of this invention.

After the drying, curing may be performed at a temperature of room temperature or higher for at least half a day, preferably for several days or longer to obtain sufficient adhesive strength. Curing temperature becomes like this. Preferably it is the range of 30-50 degreeC, More preferably, it is the range of 35-45 degreeC. When the curing temperature is within the above range, so-called "winding tightening" in a roll-wound state is less likely to occur. In addition, the humidity in particular at the time of curing is not restrict|limited, What is necessary is just to have a relative humidity in the range of 0-70 %RH. Curing time is 1 to 10 days normally, Preferably it is 2 to 7 days.

Moreover, a photocurable adhesive agent can also be used as said adhesive agent. As a photocurable adhesive agent, mixtures, such as a mixture, such as a photocurable epoxy resin and a photocationic polymerization initiator, a photocurable acrylic resin, and a radical photopolymerization initiator, are mentioned, for example. When using a photocurable adhesive agent, a photocurable adhesive agent is hardened by irradiating an active energy ray. Although the light source of the active energy ray is not particularly limited, an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable, and specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave Here, a mercury lamp, a metal halide lamp, etc. are preferable.

Although the light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, the irradiation intensity in the wavelength region effective for activation of the polymerization initiator is preferably 0.1 to 6000 mW/cm 2 , more preferably Preferably it is 10-1000 mW/cm<2>, More preferably, it is 20-500 mW/cm<2>. When the irradiation intensity is within the above range, the reaction time can be ensured, and yellowing of the epoxy resin and deterioration of the polarizing film due to heat radiated from the light source and heat generated during curing of the photocurable adhesive can be suppressed. The light irradiation time for the photocurable adhesive may be appropriately selected depending on the photocurable adhesive to be cured, and is not particularly limited, but the accumulated light amount expressed as a product of the irradiation intensity and the irradiation time is preferably 10 to 10000 mJ/m , more preferably 50 to 1000 mJ/m 2 , still more preferably 80 to 500 mJ/m 2 . When the amount of accumulated light with respect to the photocurable adhesive is within the above range, a sufficient amount of active species derived from the polymerization initiator can be generated, the curing reaction can proceed more reliably, and the irradiation time is not excessively long, and good productivity can be maintained. .

In addition, in the case of curing the photocurable adhesive by irradiation of active energy rays, for example, the polarization degree, transmittance and color of the polarizing film, and transparency of various films constituting the protective layer and the optical layer. It is preferable to harden|cure under the conditions which a function does not deteriorate.

<Optical layer>

The polarizing plate of this invention may further laminate|stack optical layers, such as a retardation film, a visual compensation film, and a brightness improvement film, as needed.

Examples of the retardation film include a birefringent film formed by subjecting a polymer material to uniaxial or biaxial stretching treatment, an alignment film of liquid crystal polymer, and a film in which an alignment layer of liquid crystal polymer is supported by a film. An extending|stretching process can be implemented by the roll extending|stretching method, the extending|stretching method along a long gap|interval, the tenter extending|stretching method, the tubular extending|stretching method, etc., for example. As for a draw ratio, in the case of uniaxial stretching, 1.1-3 times are common. Although the thickness in particular of retardation film is not restrict|limited, Usually, it is 10-200 micrometers, Preferably it is 20-100 micrometers.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, poly Sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyolefin having a norbornene structure, polychloride vinyl, cellulosic polymers, or various binary and ternary copolymers thereof, graft copolymers, blends, and the like. These polymer materials become an oriented product (stretched film) by stretching or the like.

As a liquid crystal polymer, the various polymers of the principal chain type and side chain type in which the conjugated linear atomic group (mesogen) which provides liquid-crystal orientation was introduce|transduced into the main chain or side chain of a polymer is mentioned, for example. Specific examples of the main chain liquid crystal polymer include a polyester-based liquid crystal polymer, discotic polymer, and cholesteric polymer having a structure in which a mesogenic group is bonded to a spacer portion imparting flexibility, for example, a nematic alignment property. there is. As a specific example of a side chain type liquid crystal polymer, polysiloxane, polyacrylate, polymethacrylate or polymalonate is used as a main chain backbone, and a nematic orientation imparting property through a spacer part which consists of a conjugated atom group as a side chain. and those having a mesogenic moiety composed of a para-substituted cyclic compound unit. These liquid crystal polymers are, for example, those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or a liquid crystal polymer on the surface of an alignment treatment, such as one in which silicon oxide is vapor-deposited in an oblique direction. It is carried out by developing and heat-treating a solution of

The retardation film may have a retardation according to the purpose of use, such as for the purpose of compensating for color or vision due to the birefringence of various wave plates or liquid crystal layers, for example. It may be a thing in which the optical characteristic of is controlled, etc. may be sufficient.

A visual compensation film is a film for widening a viewing angle so that an image can be seen comparatively clearly even when the screen of a liquid crystal display device is viewed from the direction slightly inclined with respect to the screen. Such a visual compensation film includes, for example, an alignment film such as a retardation film or a liquid crystal polymer, or a film in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. A typical retardation film is a polymer film having birefringence uniaxially stretched in the plane direction is used, whereas in a retardation film used as a visual compensation film, a polymer film having birefringence biaxially stretched in the plane direction is used. A polymer having birefringence in which the refractive index in the thickness direction is controlled, which is stretched uniaxially in the direction and also stretched in the thickness direction, or a bidirectionally oriented film such as an obliquely oriented film, etc. are used. Examples of the diagonally oriented film include those in which a heat-shrinkable film is adhered to a polymer film and stretched and/or contracted under the action of the shrinking force by heating, and a liquid crystal polymer in which a liquid crystal polymer is tilted. there is. As a raw material polymer for the retardation film, the same polymer as the polymer described above for the retardation film is used, and the purpose is to prevent coloring due to a change in the viewing angle based on the retardation caused by the liquid crystal cell, or to expand the viewing angle with good visibility. It can be appropriately selected and used.

In addition, from the viewpoint of achieving a wide viewing angle with good visibility, a vision compensation film in which an optically anisotropic layer made of an alignment layer of a liquid crystal polymer, particularly an oblique alignment layer of a discotic liquid crystal polymer, is supported by a triacetyl cellulose film is preferably used.

The polarizing plate which bonded the polarizing plate and the brightness improvement film together is normally installed in the back side side of a liquid crystal cell, and is used. When natural light is incident by a backlight of a liquid crystal display device or the like or reflection from the back side, the luminance enhancement film reflects linearly polarized light on a predetermined polarization axis or circularly polarized light in a predetermined direction, and transmits other light. A polarizing plate in which a film is laminated with a polarizing plate causes light from a light source such as a backlight to be incident to obtain transmitted light in a predetermined polarization state, and is reflected without transmitting light other than the predetermined polarization state. The light reflected from the brightness enhancing film surface is also inverted through a reflective layer formed on the rear side thereof to be re-entered into the brightness enhancing film, and part or all of the light is transmitted as light in a predetermined polarization state and transmitted through the brightness enhancing film. A luminance can be improved by supplying the polarization|polarized-light which is hard to be absorbed by a polarizing film, and aiming at increase of the light quantity which can be used for liquid crystal image display etc. while aiming at an increase. That is, when light is incident through the polarizing film from the back side of the liquid crystal cell by means of a backlight or the like without using a luminance enhancing film, light having a polarization direction that does not coincide with the polarization axis of the polarizing film is almost transmitted to the polarizing film. It is absorbed and does not permeate|transmit a polarizing film. That is, although it changes also with the characteristic of the polarizing film used, approximately 50% of light is absorbed by a polarizing film, the amount of light which can be used for liquid crystal image display etc. decreases by that much, and an image becomes dark. The brightness enhancement film does not make the light having a polarization direction absorbed by the polarizing film incident on the polarizing film, but reflects it once in the brightness enhancement film, and then reverses it through a reflective layer formed on the rear side thereof to re-enter the brightness enhancement film. By repeating this, only the polarized light whose polarization direction of the light reflected and reversed between these two can pass through the polarizing film is transmitted and supplied to the polarizing film. It can be used for display of , and can brighten the screen.

The polarizing plate of this invention can be manufactured by bonding a protective layer to a polarizing film with an adhesive agent, for example, and forming an adhesion layer in the surface of the protective layer by the side to be bonded together with an image display element. When the polarizing plate of the present invention further includes an optical layer, for example, various films constituting the optical layer are bonded to the protective layer with an adhesive, and an adhesive layer is formed on the surface opposite to the surface adhered to the protective layer. do. Before bonding the polarizing plate obtained by laminating|stacking each film which comprises a polarizing plate, and an image display element, the polarizing plate of this invention can be obtained by making it curved so that it may become a desired radius of curvature. Moreover, after bonding with an image display element, it can also be curved.

About bonding with an image display element, when using for a curved liquid crystal display panel, for example, what is necessary is just to bond the polarizing plate of this invention to the liquid crystal cell which is an image display element through an adhesion layer. Moreover, when using for a curved organic electroluminescent panel, what is necessary is just to bond the polarizing plate of this invention to the visual recognition side display surface of the organic electroluminescent display element which is an image display element through an adhesion layer.

In the case of a liquid crystal display panel, for example, in the case of a liquid crystal display panel, the laminate of the image display element and the concave and convex side polarizing plates produced as described above is bent to a predetermined radius of curvature and fixed to the frame, and the backlight is It can be implemented by the method of mounting on a unit, or the method of mounting the said laminated body on the backlight unit curved by the predetermined|prescribed radius of curvature, and pressing with a frame from it.

The polarizing plate of this invention can be used as a polarizing plate of curved image display panels, such as a curved liquid crystal panel and a curved organic electroluminescent panel, especially as a polarizing plate of a curved liquid crystal display panel. In a curved image display panel, a compressive stress always generate|occur|produces because the image display panel is curved. Since the compressive stress is larger on the concave surface side (viewing side), dimensional change is likely to occur in the polarizing plate positioned on the concave surface side, whereas the image display element bonding the polarizing plate is generally sandwiched by a glass substrate, so dimensional change occurs. It is difficult, and it is thought that the difference in shrinkage rate is easy to generate|occur|produce between a concave surface side polarizing plate and an image display element. For this reason, especially on the concave surface side of a curved-surface image display panel, peeling and lifting of a polarizing plate become easy to generate|occur|produce. Although the polarizing plate of the present invention can be used as either a concave-side polarizing plate or a convex-side polarizing plate constituting a curved image display panel, it has a high inhibitory effect on peeling and lifting in a curved state, so in particular the image display panel It is preferable as a concave side polarizing plate mounted on the concave side. That is, in one embodiment of the present invention, there is provided a curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate is the polarizing plate of the present invention. Further, in another embodiment of the present invention, there is provided a curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate and the convex-side polarizing plate are the polarizing plates of the present invention.

Further, when the polarizing plate of the present invention is used in a liquid crystal display panel, the convex surface-side polarizing plate and the concave-side polarizing plate are arranged so that the absorption axis direction (stretching direction) of each polarizing film contained in these polarizing plates is perpendicular to each other. For example, as shown in FIG. 4 , if the absorption axis direction of the polarizing film included in the concave-side polarizing plate is horizontal, the absorption-axis direction of the polarizing film included in the convex-side polarizing plate is vertical. Moreover, as shown in FIG. 5, if the absorption axis direction of the polarizing film contained in the concave surface side polarizing plate is a vertical direction, the absorption axis direction of the polarizing film contained in a convex surface side polarizing plate is a horizontal direction. The absorption axis direction of the polarizing film included in the concave-side polarizing plate may be a vertical direction, a horizontal direction, or an angular direction of 45° with respect to the horizontal direction. In most image display panel products, the absorption axis direction of the polarizing film included in the concave-side polarizing plate is in the horizontal direction, especially in this case, deformation such as shrinkage of the polarizing plate is easy to occur, and peeling or lifting of the polarizing plate is easy to occur. discovered in the invention. ADVANTAGE OF THE INVENTION According to the polarizing plate of this invention, even if the direction of an absorption axis is a horizontal direction, generation|occurrence|production of a flaw on the surface of a polarizing plate can be suppressed, and the said subject can be solved.

Moreover, the polarizing plate of this invention can be used suitably for the curved image display panel which has various screen sizes. For example, 5 inches (horizontal length: 100 to 150 mm), 10 inches (horizontal length: 200 to 250 mm), 17 inches (horizontal length: 320 to 400 mm), 32 inches (horizontal length: 680 to 720 mm), 40 inches (horizontal length: 860 to 910 mm), 46 inches (horizontal length: 980 to 1030 mm), 55 inches (horizontal length: 1180 to 1230 mm), 65 inches (horizontal direction) Length: 1400 to 1450 mm), 75 inches (horizontal length: 1600 to 1700 mm), and 85 inches (horizontal length: 1800 to 1900 mm) can be used for a curved image display panel having a screen size. The larger the screen size, the larger the size of each constituent member, and while compressive stress acts on the concave-side polarizing plate in a curved state, and the mismatch of dimensions between the polarizing plate and the image display element occurs, peeling or lifting of the polarizing plate is particularly easy to occur. . Further, in an image display device having a screen aspect ratio (vertical length: horizontal length) of 3:4, peeling off or lifting of the polarizing plate is unlikely to occur, but the aspect ratio of the screen is 9:13 to 9:23, preferably 9 : 15 or more, more preferably 9:19 or less, for example, in a horizontally long image display panel of 9:16 or 9:21, compressive stress acts on the concave-side polarizing plate at the time of curvature, When the discrepancy of the dimension of a polarizing plate and an image display element arises, it is also discovered by the present inventors that peeling and floatation of a polarizing plate are especially easy to produce. Since the polarizing plate of the present invention has a high inhibitory effect on peeling and lifting in a curved state, it can be preferably used as a polarizing plate for various screen sizes, particularly a relatively large screen size or a horizontally long curved image display panel as described above. can

The curved image display panel of this invention containing the polarizing plate of this invention is excellent in the effect of suppressing peeling and lifting of the polarizing plate from an image display panel under a long-term and/or high-temperature environment.

Example

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

1. Fabrication of polarizing film

A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and having a thickness of 60 µm (trade name “VF-PE#6000” manufactured by Kuraray Co., Ltd.) was immersed in pure water at 30° C., followed by iodine/iodination. It was immersed at 30 degreeC in the aqueous solution whose mass ratio of potassium/water is 0.02/2/100. Then, it was immersed at 56.5 degreeC in the aqueous solution whose mass ratio of potassium iodide/boric acid/water is 12/5/100. Then, after wash|cleaning a film using 8 degreeC pure water, it was made to dry at 80 degreeC, and the polarizing film which iodine adsorption-orientated to the polyvinyl alcohol film was obtained. Extending|stretching was performed mainly in iodine dyeing and a boric-acid process, and the total draw ratio was 6.0 times. The thickness of the polarizing film obtained in this way was 22 micrometers.

2. Preparation and preparation of protective layer (protective film)

Various protective layers (protective films) were produced or prepared as follows.

(1) Acrylic resin film (2-A)

While mixing 70 mass % of methacrylic resin and 30 mass % of rubber particles with a super mixer, 2 mass % of a benzotriazole type ultraviolet absorber was added with respect to 100 mass % of the mixture, it melt-kneaded with the twin screw extruder, and it was set as pellet. This pellet is put into a 65 mmφ single screw extruder, extruded through a T-die with a set temperature of 275°C, cooled by sandwiching the film with two polishing rolls having a mirror surface, and an acrylic resin film with a thickness of 80 µm (2-A) was obtained.

In addition, as said methacrylic resin, the copolymer of methyl methacrylate/methyl acrylate =96%/4% (mass ratio) was used. In addition, as the rubber particles, the innermost layer is made of a hard polymer polymerized using methyl methacrylate and a small amount of allyl methacrylate, and the middle layer has butyl acrylate as a main component, and also styrene and a small amount of allyl methacrylate. is a three-layered elastomer particle composed of a soft elastomer polymerized using 240 nm was used. In addition, in this rubber particle, the total mass of an innermost layer and an intermediate|middle layer was 70 % of the whole particle|grains.

(2) Acrylic resin film having a hard coat layer (2-B)

On the said acrylic resin film (2-A), the hard-coat process was implemented. The hard coat treatment is a treatment solution (pentaerythritol triacrylate: 42.5 parts by mass, Irgacure 184: 0.25 parts by mass, silicone (leveling agent): 0.1 parts by mass, silica (average particle size 1 µm): 12 parts by mass, Surface methacryloyl group-modified silica (surface organic component: 4.05 × 10 ^-3 g/m 2 ): 7.5 parts by mass, toluene: 34 parts by mass) is applied, dried, and then irradiated with ultraviolet rays using an ultraviolet irradiator. did In this way, the acrylic resin film (2-B) (total thickness: 85 micrometers) which has a 5 micrometers-thick hard-coat layer was obtained.

(3) TAC film (2-C)

Konica Minolta Opto Co., Ltd. triacetyl cellulose film "KC6UAW" (thickness: 60 micrometers) was used as TAC film (2-C).

(4) TAC film (2-D)

On the said (2-C) TAC film, the hard-coat process was implemented similarly to (2-B). In this way, the TAC film (2-D) (total thickness: 65 micrometers) which has a 5 micrometers-thick hard-coat layer was obtained.

(5) COP film (2-E)

Nippon Zeon Co., Ltd. cyclic polyolefin-type biaxially stretched resin film "Zeonor Film ZB12" (52 micrometers in thickness) was used as COP film (2-E).

3. Preparation of adhesive

A solvent-free UV-curable adhesive obtained by mixing the following ingredients was used as the adhesive. In addition, % shows content (mass %) when the whole adhesive agent is 100 mass %.

-3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate ("Celoxide 2021P" manufactured by Daicel Chemical Industry Co., Ltd.): 80%

· 1,4-butanediol diglycidyl ether: 19%

A photocationic polymerization initiator containing triarylsulfonium hexafluorophosphate as a main component (CPI-100P: propylene carbonate solution containing 50% of an active ingredient containing triarylsulfonium hexafluorophosphate as a main component, manufactured by San Apro Co., Ltd.) of 「CPI-100P」): 1%

4. Preparation of adhesive

In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 81.8 parts by mass of ethyl acetate, 70.8 parts by mass of butyl acrylate, 20.0 parts by mass of methyl acrylate, 8.0 parts by mass of 2-phenoxyethyl acrylate, 8.0 parts by mass of acrylic acid 2-hydroxy 1.0 mass part of ethyl and 0.6 mass part of acrylic acid were inject|poured, and the internal temperature was raised to 55 degreeC while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Then, the whole amount of the solution which melt|dissolved 0.14 mass parts of azobisisobutyronitrile which is a polymerization initiator in 10 mass parts of ethyl acetate was added. Maintaining this temperature for 1 hour after addition of the polymerization initiator, and then maintaining the internal temperature at 54 to 56°C, ethyl acetate is continuously added into the reaction vessel at an addition rate of 17.3 parts by mass/hour, the concentration of the acrylic resin is 35 mass When it became %, addition of ethyl acetate was stopped. Moreover, it kept at this temperature until 12 hours passed from the start of addition of ethyl acetate. Finally, ethyl acetate was added, and it adjusted so that the density|concentration of an acrylic resin might be set to 20 mass %. This was made into an acrylic resin.

The weight average molecular weight and number average molecular weight of the obtained acrylic resin were measured according to the following method. In the GPC apparatus, as a column, 4 "TSKgel XL" manufactured by Tosoh Corporation and 1 "Shodex GPC KF-802" sold by Shoko Co., Ltd. manufactured by Showa Denko Co., Ltd., total of 5 pieces were connected in series, using tetrahydrofuran as an eluent, sample concentration of 5 mg/ml, sample introduction amount of 100 µl, temperature of 40°C, and flow rate of 1 ml/min. Measured by standard polystyrene conversion. The weight average molecular weight Mw of the obtained acrylic resin was 1.42 million, and Mw/Mn was 4.1.

With respect to 100 parts by mass of the solid content of the acrylic resin (20 mass% ethyl acetate solution) prepared above, 0.5 parts by mass of glycidoxypropyltrimethoxysilane (liquid) as a silane compound (KBM-403 manufactured by Shin-Etsu Chemical Industry Co., Ltd.) ), 0.6 parts by mass of coronate HXR as a crosslinking agent (isocyanurate of hexamethylene diisocyanate, liquid containing approximately 100% by mass of active ingredient, manufactured by Nippon Polyurethane Co., Ltd.), and 3.0 parts by mass of N-octyl-4- Methylpyridinium hexafluorophosphate was mixed. Then, ethyl acetate was added so that solid content concentration might be 13 mass %, and the adhesive was obtained.

Example 1

Film (2-D) and film (2-E) which are protective layers corona-treated previously using the corona treatment machine (made by Kasuga Electric Corporation), apply|coated the adhesive agent on it, and bonded it to the polarizing film. Then, ultraviolet rays were irradiated with a metal halide lamp to harden the adhesive. The layer of the 20-micrometer adhesive was formed on the film (2-E) surface, and the concave surface side polarizing plate A of thickness 0.17mm (The separator film used for adhesive layer formation is excluded) was obtained.

Moreover, except having used the film (2-C) instead of the film (2-D), it carried out similarly to the above, and obtained the convex-surface side polarizing plate B of thickness 0.16mm (the separator film used for adhesive layer formation is excluded).

The polarizing plate A was cut into a size of 1215 mm horizontal (horizontal direction length) × vertical (vertical direction length) 683 mm, and at this time, the polarizing plate A was cut so that the absorption axis direction became the horizontal direction. Moreover, the polarizing plate B was cut|disconnected to the size of 1215 mm wide x 683 mm long, and it cut|disconnected so that the absorption axis direction of the polarizing plate B might become a longitudinal direction at this time. The cut polarizing plate A was bonded to the viewing side (concave side) of a glass panel having a width of 1215 mm × vertical 683 mm and a thickness of 1.5 mm, and the cut polarizing plate B was bonded to the back side (convex side) of this panel. . Then, the glass panel was bent and fixed so that an average radius of curvature might be set to 4000 mm, and it hold|maintained under 80 degreeC dry condition for 250 hours. After 250 hours, when the external appearance of the panel was observed with the naked eye, peeling or floating of the polarizing plate did not occur. The dimensional change rate measured by the said method was 0.8 %. In addition, at this time, it was L1(H+H1)/2R=0.25.

Example 2

Film (2-B) and film (2-E) which are protective layers corona-treated previously using the corona treatment machine (made by Kasuga Electric Corporation), apply|coated the adhesive agent on it, and bonded it to the polarizing film. . Then, ultraviolet rays were irradiated with a metal halide lamp to harden the adhesive. A layer of a 20 µm pressure-sensitive adhesive was formed on the film (2-E) surface to obtain a concave-side polarizing plate C having a thickness of 0.19 mm (excluding the separator film used for forming the pressure-sensitive adhesive layer).

Moreover, except having used the film (2-A) instead of the film (2-B), it carried out similarly to the above, and obtained the convex-surface side polarizing plate D of thickness 0.18mm.

The polarizing plate C was cut|disconnected to the size of 1215 mm wide x 683 mm long, and it cut|disconnected so that the absorption axis direction of the polarizing plate C might become a horizontal direction at this time. Moreover, the polarizing plate D was cut|disconnected to the size of 1215 mm wide x 683 mm long, and it cut|disconnected so that the absorption axis direction of the polarizing plate D might become a longitudinal direction at this time. The cut polarizing plate C was bonded to the viewing side (concave side) of a glass panel having a width of 1215 mm x 683 mm and a thickness of 1.5 mm, and the cut polarizing plate D was bonded to the back side (convex side) of this panel. . Thereafter, the panel was bent and fixed so that the average radius of curvature was 4000 mm, and the panel was kept under dry at 80°C for 250 hours. After 250 hours, when the external appearance of the panel was observed with the naked eye, peeling or floating of the polarizing plate did not occur. The dimensional change rate measured by the said method was 1.4 %. In addition, at this time, L1(H+H1)/2R=0.26.

Example 3

What cut the size of the polarizing plates C and D to the size of 1440 mm x 810 mm in width, and the polarizing plates C and D are pasted together to the glass panel of 1440 mm x 810 mm in width, and thickness 1.5mm thickness, and average radius of curvature Except having bent and fixed the panel so that it might be set to this 6600 mm, it carried out similarly to Example 2, and evaluated peeling of the polarizing plate in a curved panel, and floating|lifting. As a result, the large peeling and lifting of a polarizing plate did not generate|occur|produce. The dimensional change rate measured by the said method was 1.4 %. In addition, at this time, L1(H+H1)/2R=0.18.

Comparative Example 1

Except having set the average radius of curvature of a panel to 2500 mm, it carried out similarly to Example 2, and evaluated the peeling and floatation of the polarizing plate in a curved panel. As a result, in the short side of the concave-surface-side polarizing plate C, floating occurred from the glass to 50 mm from the side end. The dimensional change rate measured by the said method was 1.4 %. In addition, at this time, L1(H+H1)/2R=0.41.

Example 4

The size of the polarizing plates C and D is cut to the size of 1440 mm wide x 810 mm long, and the polarizing plates C and D are adhered to a glass panel having a thickness of 1440 mm x 810 mm and a thickness of 1.5 mm. When peeling and lifting of the polarizing plate in a curved panel are evaluated similarly to Example 2, it will be L1(H+H1)/2R=0.30, and generation|occurrence|production of large peeling and float of a polarizing plate will be suppressed.

Example 5

The size of the polarizing plates C and D is cut to the size of 1660 mm x 934 mm in width, and polarizing plates C and D are 1660 mm x 934 mm in width, and sticking together to the glass panel of thickness 1.5mm thickness, except that When peeling and lifting of the polarizing plate in a curved panel are evaluated similarly to Example 2, it will be L1(H+H1)/2R=0.35, and generation|occurrence|production of large peeling and float of a polarizing plate will be suppressed.

Example 6

Cutting the size of the polarizing plates C and D to a size of 900 mm wide × 506 mm long, bonding the polarizing plates C and D to a glass panel having a width of 900 mm × length 506 mm and a thickness of 1.5 mm thickness, and the panel When peeling and lifting of the polarizing plate in a curved panel are evaluated in the same manner as in Example 2 except that the average radius of curvature is 2500 mm, L1(H+H1)/2R=0.30, and large peeling of the polarizing plate The occurrence of lifting is suppressed.

Example 7

Cutting the size of the polarizing plates C and D to a size of 508 mm x 286 mm in width, bonding the polarizing plates C and D to a glass panel having a thickness of 508 mm x 286 mm in width and 1.5 mm in thickness, and the panel When peeling and lifting of the polarizing plate in a curved panel are evaluated in the same manner as in Example 2 except that the average radius of curvature is 2500 mm, L1(H+H1)/2R=0.17, large peeling of the polarizing plate or The occurrence of lifting is suppressed.

Comparative Example 2

When peeling and lifting of the polarizing plate in the curved panel are evaluated in the same manner as in Example 4 except that the average radius of curvature of the panel is 2500 mm, L1(H+H1)/2R=0.49, peeling of the polarizing plate or the occurrence of lifting occurs.

Comparative Example 3

Except that the average radius of curvature of the panel is 2500 mm, when the peeling and lifting of the polarizing plate in the curved panel are evaluated in the same manner as in Example 5, L1(H+H1)/2R=0.56, and the peeling of the polarizing plate is performed. or the occurrence of lifting occurs.

Comparative Example 4

When peeling and lifting of the polarizing plate in the curved panel are evaluated in the same manner as in Example 6 except that the average radius of curvature of the panel is 1000 mm, L1(H+H1)/2R=0.76, and peeling of the polarizing plate or the occurrence of lifting occurs.

Comparative Example 5

Except that the average radius of curvature of the panel is 1000 mm, when the peeling and lifting of the polarizing plate in the curved panel are evaluated in the same manner as in Example 7, L1(H+H1)/2R=0.43, and peeling of the polarizing plate or the occurrence of lifting occurs.

Example 8

What cut the size of the polarizing plates A and B to the size of 1050 mm wide x 600 mm long, and the polarizing plates A and B were pasted together to the glass panel of 1050 mm wide x 600 mm long, and thickness 1.5mm thickness, and average curvature radius Except having bent and fixed the panel so that it might be set to this 2500 mm, it carried out similarly to Example 1, and evaluated the peeling and floating of the polarizing plate in a curved panel. As a result, the large peeling and lifting of a polarizing plate did not generate|occur|produce. The dimensional change rate measured by the said method was 0.8 %. In addition, at this time, L1(H+H1)/2R=0.35.

5. Evaluation of adhesion to glass

(1) Measurement of adhesion to glass

(a) Measurement of "Adhesive force to glass (flat surface, 23 °C)" and "Adhesive force to glass (curved surface, 23 °C)"

Autoclave treatment for 20 minutes at 50° C., 5 kg/cm 2 (490.3 kPa, gauge pressure) to each of the test pieces for measuring the adhesion to glass in the flat state and the curved state prepared in Examples 1 and 2 After carrying out, it was left still for 24 hours in 23 degreeC, 50%RH environment, and using the Shimadzu Corporation autograph (AGS-50NX), respectively chucking a glass panel and a polarizing plate, 180 degree direction at a speed|rate of 300 mm/min. to peel off the polarizing plate. The peel strength measured by this was made into "adhesive force to glass (flat surface, 23 degreeC)" and "adhesive force to glass (curved surface, 23 degreeC)". A result is shown in Table 1.

(b) Measurement of “adhesion to glass (flat surface, 80° C.)” and “adhesion to glass (curved surface, 80° C.)”

For each separate set of test specimens for measuring adhesion to glass in a flat state and a curved state prepared in Examples 1 and 2, 50 ° C., 5 kg/cm 2 (490.3 kPa, gauge pressure) for 20 minutes After performing the clave treatment, the glass panel and the polarizing plate were left still for 24 hours at 23°C and 50%RH environment, and then left still for 250 hours in a dry environment at 80°C, using an autograph (AGS-50NX) manufactured by Shimadzu Corporation. Each chuck was carried out, and the polarizing plate was peeled off in a direction of 180° at a speed of 300 mm/min. The peel strength measured by this was made into "adhesive force to glass (flat surface, 80 degreeC)" and "adhesive force to glass (curved surface, 80 degreeC)". A result is shown in Table 1.

1: Concave side polarizing plate
2: Convex side polarizing plate
3: image display element
10: adhesive layer
11: protective layer
12: polarizing film
13: surface treatment layer

Claims (9)

A polarizing plate having a horizontal length of L1 (mm) in a planar state that is bonded to a curved image display panel having an average radius of curvature R (mm) and a thickness H (mm) via an adhesive layer,
Polarizing plate thickness H1 (mm) used as a concave surface side when it is pasted together by a curved image display panel is following formula (1):
L1(H + H1)/2R ≤ 0.4 (1)
satisfied with
The horizontal length L1 of the polarizing plate in a planar state is 500 mm or more and 2500 mm or less,
The adhesive force of the adhesive layer to glass measured in a planar state at 23°C and 50%RH is 1.0 N/25 mm or more and 20.0 N/25 mm or less,
The polarizing plate whose dimensional change rate after 250 hours under 80 degreeC dry of a polarizing plate is 3.0 % or less. The method of claim 1,
Adhesive force to the glass is 2.0 N/25 mm or more and 20.0 N/25 mm or less, a polarizing plate. The method of claim 1,
The polarizing plate whose adhesive force with respect to the glass measured in the curved-surface state in 23 degreeC and 50 %RH of an adhesion layer is 1.5 N/25 mm or more and 20.0 N/25 mm or less. The method of claim 1,
The polarizing plate whose thickness H of a curved image display panel is 0.4 mm or more and 2.0 mm or less. The method of claim 1,
The polarizing film in a polarizing plate is a polarizing plate which is the polyvinyl alcohol film by which the extending|stretching and dyeing|dye were carried out. The method of claim 1,
A curved image display panel is a polarizing plate which has an average radius of curvature R of 900-7000 mm. A curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate is the polarizing plate according to any one of claims 1 to 6. A curved image display panel comprising a concave-side polarizing plate and a convex-side polarizing plate, wherein the concave-side polarizing plate and the convex-side polarizing plate are the polarizing plates according to any one of claims 1 to 6. delete

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