KR20170021754A - Polarizing plate for curved image display panel - Google Patents

Abstract

[OBJECTIVE] To provide a polarizing plate for a curved image display panel capable of suppressing a curved display panel from being peeled by a user under long-term use and/or high temperature environment. [SOLUTION] Provided is a polarizing plate used in a curved image display panel having an average curvature radius R and a thickness H and having a horizontal length L1 in a planar state. The thickness H1 of the polarizing plate which becomes a concave surface side when it is adhered to the curved image display pane, satisfies a fallowing equation (1) : L1(H + H1)/2R <= 0.4 (1).

Description

POLARIZING PLATE FOR CURVED IMAGE DISPLAY PANEL [

The present invention relates to a polarizing plate used in 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, a polarizing plate in which a dichroic dye such as iodine or a dichroic dye is aligned and adsorbed on a polyvinyl alcohol- A polarizing plate having a structure in which a protective film such as a triacetylcellulose film is laminated on one side or both sides of a polarizing film through an adhesive layer is known (for example, Patent Documents 1 to 3). Such a polarizing plate is laminated (adhered) to an image display element such as a liquid crystal cell or an organic EL display element in the form of lamination of various optical layers such as a retardation film or an optical compensation film as necessary, .

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

Recently, image display apparatuses of various shapes have been studied from the viewpoint of designability. Particularly, a difference in distance from the viewer to the center of the screen and the side end (side end) is small, and a feeling of immersion in the screen is obtained, so that a curved image display apparatus such as a curved- Product development is being done.

Even in the curved image display apparatus, it is necessary to use a polarizing plate similarly to the flat image display apparatus. However, when the conventional polarizing plate disclosed in the above Patent Documents 1 to 3 is used for the curved display panel in order to manufacture the curved image display apparatus, The polarizing plate may peel off or peel off from the curved display panel. In the curved display panel, peeling off and peeling of the polarizing plate is particularly likely to occur on the concave side (viewing side), leading to display failure in the viewing area. In addition, the occurrence of peeling and peeling of the polarizing plate from the curved display panel becomes particularly remarkable under a high temperature environment. For this reason, there is a possibility of causing more severe peeling or lifting depending on the long-term use of the light source for a long period of time, transportation of the light source over a long period of time, and transportation in a high temperature and high humidity environment.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems inherent in a polarizing plate used in a curved image display panel, and it is an object of the present invention to provide a polarizing plate for use in a curved- And a polarizing plate for a curved image display panel capable of suppressing a curved image display panel.

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

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

The thickness H1 (mm) of the polarizer, which becomes the concave surface side when being adhered to the curved image display panel, satisfies the following formula (1):

L1 (H + H1) / 2R? 0.4 (1)

/ RTI &gt;

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

[3] The polarizing plate according to the above [1] or [2], wherein the dimensional change after 250 hours at 80 캜 in a dry state 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 polarizer according to any one of [1] to [4], wherein the curved image display panel has an average curvature radius R of 900 to 7000 mm.

[6] A polarizing plate according to any one of [1] to [5], wherein a 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 surface side polarizing plate and a convex surface side polarizing plate, wherein the concave surface 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 surface side polarizing plate and a convex surface side polarizing plate, wherein the concave surface side polarizing plate and the convex surface side polarizing plate are the polarizing plates described in any one of the above [1] to [6].

According to the present invention, it is possible to provide a polarizing plate for a curved image display panel capable of suppressing the peeling and lifting of the curved surface from the display panel even by long-term use and / or use under a high temperature environment.

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

Hereinafter, embodiments of the present invention will be described in detail.

In the present invention, the term &quot; planar state &quot; means a state in which it is entirely planar without including a curved portion. The term &quot; curved surface state &quot; generally means a case in which a curved surface is formed entirely including a state in which the whole is curved by one arc, and a curved portion in one or more arcs. In the present invention, the &quot; average radius of curvature &quot; is an average value of curvature radii at three points on the left and right ends and the center of the image display panel. That is, in FIG. 1, the average radius of curvature is a value calculated by (R _L + R _in + R _R) / 3.

The present invention relates to a polarizing plate used in a curved image display panel having an average curvature radius R (mm) and a thickness H (mm). The thickness H1 (mm) of the polarizing plate which becomes the concave surface side when adhered to the curved image display panel is expressed by the following equation (1): L1 (mm) in the horizontal direction in the planar state of the polarizing plate of the present invention,

L1 (H + H1) / 2R? 0.4 (1)

. In the present invention, the concave side refers to the side corresponding to the visual side of the curved image display panel, and the convex side refers to the side opposite to the concave side.

Here, a polarizing plate having the same horizontal length on the image display panel having the horizontal length L1 and the thickness H in the planar state and having the thickness H1 is stacked, and the average curvature radius R (Refer to Fig. 2), the length of the central portion of the panel is not changed because it is a standard. On the other hand, the horizontal length (defined as the length of the center position of the thickness of the polarizing plate) of the polarizing plate after being curved is calculated as the length of the arc of radius of curvature {R - (H + H1) / 2}. The present 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, it is preferable that the following expression:

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

, That is to say, not more than 0.4, is important for suppressing the peeling off and lifting of the polarizing plate.

The value of L1 (H + H1) / 2R in the formula (1) is 0.40 or less, preferably 0.38 or less, more preferably 0.35 or less, and still more preferably 0.30 or less. If the value of L1 (H + H1) / 2R in the formula (1) is not more than the upper limit value, peeling or lifting of the polarizing plate from the curved image display panel can be prevented even by long- It is hard to get. The value of L1 (H + H1) / 2R in formula (1) is usually 0.01 or more.

The curved image display panel is generally curved in the vertical direction (up and down direction) and curved in the horizontal direction (left and right direction) so that the viewer side becomes concave and the opposite side (backlight unit side) Shape, and constitutes a part of a cylinder whose center axis is vertical (upward and downward).

The curved image display panel preferably has a thickness H of 0.4 mm or more, more preferably 0.8 mm or more, and more preferably 1.0 mm or more. If the thickness H of the curved image display panel is equal to or smaller than the lower limit value, various materials can be used as members used in the curved image display panel, and handling is facilitated even when the display panel is enlarged. The thickness H of the curved image display panel is usually 2.0 mm or less.

The curved image display panel preferably has an average radius of curvature R of 7000 mm or less, more preferably 6600 mm or less, more preferably 5000 mm or less, still more preferably 4000 mm or less, particularly preferably 3000 mm or less Respectively. The curved image display panel has an average curvature radius R of, for example, 300 mm or more, preferably 900 mm or more, more preferably 1000 mm or more, and more preferably, 1200 mm or more. The curved image display panel preferably has an average curvature radius R of 900 to 7000 mm, more preferably 1000 to 6600 mm. When the average curvature radius R of the curved image display panel is equal to or smaller than the upper limit value, the difference between the distance from the viewer to the center of the screen and the end of the screen becomes smaller, and the immersion feeling on the screen can be further obtained. When the average curvature radius R of the curved image display panel is equal to or smaller than the lower limit value, peeling or lifting of the polarizing plate from the curved image display panel due to use for a long period of time or under a high temperature environment is further suppressed.

The average curvature radius R of the curved image display panel also varies depending on the apparatus to be 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 (the curvature ratio is larger). Also, devices having a large-sized display such as a curved display television may be designed to reduce the average radius of curvature R to increase the feeling of immersion. Since the polarizing plate of the present invention is excellent in the effect of suppressing the peeling off and lifting of the polarizing plate from the display panel even in use in a long term and / or a high temperature environment in a state where the average radius of curvature R is small, In particular, 900 to 5000 mm, more preferably 1000 to 4000 mm, in a curved image display panel having an average curvature radius R.

In the polarizing plate of the present invention, the horizontal length L1 in the planar state is preferably 500 mm or more, more preferably 700 mm or more, further preferably 1100 mm or more, still more preferably 1400 mm or more. When the horizontal length L1 of the polarizing plate of the present invention in the planar state is equal to or larger than the above lower limit value, the horizontal length of the applicable curved image display panel is increased, and the immersion feeling on the screen can be further obtained. In the polarizing plate of the present invention, the horizontal length L1 in the planar state is usually 2500 mm or less. The horizontal direction of the polarizing plate corresponds to the horizontal direction of the curved image display apparatus including the curved image display panel, and the vertical direction of the polarizing plate is the direction perpendicular to the horizontal direction. The vertical length of the polarizing plate of the present invention in the planar state is determined by the horizontal length L1 and the aspect ratio of the curved image display panel.

When a conventional polarizing plate is used in the production of a curved image display panel, there is a high possibility that peeling or lifting of the polarizing plate from the curved image display panel occurs in a long-term use even at room temperature, However, the use of the polarizing plate in the high temperature environment further promotes the peeling off and lifting of the polarizing plate from the curved image display panel. This reason is considered to be due to the horizontal deformation / compressive stress caused by the polarizing plate being curved, though not limited to a particular theory. In order to suppress the deformation and compressive stress, it is preferable to change the thickness H1 of the polarizing plate in accordance with the average curvature radius R, the thickness H and the horizontal length L1 of the curved image display panel to prevent peeling of the polarizing plate from the curved image display panel I think that it is effective in restraining depression. In the present invention, the thickness H1 of the polarizing plate is determined so as to satisfy the above-described formula (1), thereby suppressing the peeling off and lifting of the polarizing plate.

The polarizing plate of the present invention has a dimensional change rate after 250 hours at 80 占 폚 in dryness of preferably 3.0% or less, more preferably 2.0% or less, further preferably 1.5% or less. If the rate of dimensional change of the polarizing plate is less than the upper limit value, contraction and / or expansion of the polarizing plate in a long-term use or in a high-temperature environment can be suppressed, so that peeling or lifting of the polarizing plate from the curved- Loses. The dimensional change rate of the polarizing plate is usually 0% or more.

The dimensional change ratio can be controlled by suppressing the dimensional change of the polarizing film that contributes to the contraction and expansion of the polarizing plate. The dimensional change of the polarizing film can be controlled by, for example, changing the manufacturing conditions and kinds of the polarizing film, such as the stretching magnification, or increasing the rigidity of the protective layer adjacent to the polarizing film. More specifically, the dimensional change can be controlled by setting the drawing magnification to preferably 8 times or less, more preferably 7.5 times or less, and more preferably 7 times or less.

The rate of dimensional change can be calculated by measuring the polarizing plate cut into a size of 100 mm x 100 mm and measuring the dimensions after the initial dimension and after 250 hours at 80 deg. C and without comparing with the glass. Naturally, the rate of dimensional change in the case of bonding to glass via a pressure-sensitive adhesive becomes smaller than the rate of dimensional change in the above-described glass subassembly. The dimensional change ratio in the glass subassembly is usually about 1/2 to 1/15, though it may vary depending on the kind of the pressure-sensitive adhesive.

The polarizing plate of the present invention is not limited in its constitution as long as it has a function as a polarizing plate. For example, in one preferred embodiment, a polarizing film, an adhesive on one side or both sides of the polarizing film A protective layer laminated thereon, and an adhesive layer for bonding to the image display element, and optionally an optical layer.

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 via an adhesive.

3, the polarizing plate of the present invention comprises a pressure-sensitive adhesive layer 10 in order from the layer adjacent to the image display element 3, and the polarizing plate and the curved image display panel according to one embodiment of the present invention, A protective layer 11, a polarizing film 12, a protective layer 11 and, if necessary, an optical layer (not shown). Usually, the polarizing film 12 and the protective layer 11 are laminated via an adhesive. The curved image display panel of the present invention is characterized in that the image display element 3 and the concave surface side polarizer 1 (hereinafter referred to as &quot; 1 &quot;) bonded to the image display element 3 via the adhesive layer 10 ) And the convex-surface-side polarizing plate (2). In the embodiment of the present invention, the concave-surface-side polarizing plate 1 is provided with the adhesive layer 10, the protective layer 11, the polarizing film 12, the protective layer And the convex surface side polarizing plate 2 is constituted of the adhesive layer 10 and the protective layer 13 in this order from the layer adjacent to the image display element 3, (11), a polarizing film (12), a protective layer (11) and, if necessary, an optical layer.

Hereinafter, each component of the polarizing plate of the present invention will be described in detail.

<Adhesive Layer>

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, conventionally known pressure-sensitive adhesives can be used without any particular limitation. For example, a pressure-sensitive adhesive having a base polymer such as acrylic, rubber, urethane, silicone or polyvinyl ether can be used. It may also be an energy ray curable pressure sensitive adhesive, a thermosetting pressure sensitive adhesive, or the like. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer having excellent transparency, adhesive strength, reworkability, weather resistance and heat resistance is preferable.

Examples of the acrylic pressure-sensitive adhesive include (meth) acrylate base polymer such as (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, And a copolymer base polymer containing two or more of these (meth) acrylic acid esters and the like is preferably used. Polar monomers are also copolymerized in these base polymers. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, 2-N, (Meth) acrylate, and glycidyl (meth) acrylate. These monomers may be used alone or in combination of two or more.

These acrylic pressure-sensitive adhesives can be used alone, but are usually used in combination with a crosslinking agent. Examples of the crosslinking agent include a divalent or polyvalent metal ion which forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound which forms an amide bond with a carboxyl group, a polyepoxy compound or a polyol compound, Forming an ester bond with a carboxyl group, forming a polyisocyanate compound and forming an amide bond with a carboxyl group, and the like. Among them, polyisocyanate compounds are widely used.

The energy ray curable pressure sensitive adhesive has a property of being cured by irradiation with energy rays such as ultraviolet rays or electron rays and has adhesion even before energy ray irradiation so that it adheres to an adherend such as a film and cures by irradiation of energy rays to adjust adhesion Is a pressure-sensitive adhesive having properties capable of being used. As the energy radiation curable pressure sensitive adhesive, it is particularly preferable to use an ultraviolet curable pressure sensitive adhesive. The energy ray curable pressure sensitive adhesive generally comprises an acrylic pressure sensitive adhesive and an energy ray polymerizable compound as a main component. Usually, a crosslinking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer and the like may be blended.

In addition to the base polymer and the cross-linking agent, the pressure-sensitive adhesive layer may contain, for example, a resin such as a natural or synthetic resin, a tackifier resin, an antioxidant, an antioxidant, An antistatic agent, an ultraviolet absorber, a dye, a pigment, a defoaming agent, a corrosive agent, a photopolymerization initiator, and a thermal polymerization initiator. It is also possible to form a pressure-sensitive adhesive layer containing fine particles and exhibiting light scattering properties. Examples of the ultraviolet absorber include a salicylate 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-based compound, and it is particularly preferable to add a silane-based compound to the acrylic resin before the crosslinking agent is blended. Since the silane-based compound improves the adhesion to glass, the adhesion between the image display element and the adhesive layer sandwiched by the glass substrate can be improved by including the silane-based compound, and a high adhesion to the display panel can be ensured. Or even when used under a high-temperature environment, peeling or lifting of the curved surface from the display panel is less likely to occur.

The pressure-sensitive adhesive layer can be formed, for example, by a method in which the above-mentioned pressure-sensitive adhesive is used as an organic solvent solution and applied on a film or layer (for example, polarizing film or the like) to be laminated by a die coater or a gravure coater, As shown in FIG. It is also possible to form a sheet-like pressure-sensitive adhesive on a release film-treated plastic film (referred to as a separator film) by transferring the pressure-sensitive adhesive sheet onto a film or layer to be laminated. The thickness of the adhesive layer is not particularly limited, but is preferably in the range of 2 to 40 mu m, more preferably in the range of 5 to 35 mu m, and more preferably in the range of 10 to 30 mu m. When the thickness of the adhesive layer is not less than the above lower limit value, it is possible to further suppress occurrence of peeling and peeling due to use for a long period of time and / or use under a high temperature environment. If the thickness of the pressure-sensitive adhesive layer is less than the above upper limit value, the increase in the thickness of the polarizing plate is suppressed. As a result, the pressure-sensitive adhesive layer is hardly deformed in the curved surface state and the occurrence of peeling or peeling due to use for a long period of time and / . This makes it possible to suppress deterioration of the display function around the frame of the image display apparatus.

In a preferred embodiment, the pressure sensitive adhesive layer of the polarizing plate of the present invention is an acrylic resin, a silane compound, and an isocyanate as a crosslinking agent, which are copolymers of butyl acrylate, methyl acrylate, 2-phenoxyethyl acrylate, 2-hydroxyethyl acrylate, Compounds.

In a preferred embodiment, the polarizing plate of the present invention comprises an adhesive layer. The adhesive strength of the adhesive layer to a glass measured in a planar state at 23 ° C and 50% RH (hereinafter sometimes referred to as "adhesive force to glass (plane, 23 ° C)") is preferably 1.0 N / 25 mm or more, and more preferably 2.0 N / 25 mm or more. If the adhesive force (plane, 23 ° C) of the adhesive layer to the glass is 1.0 N / 25 mm or more, it is preferable that the adhesive force of the polarizing plate from the curved image display panel in the long- It is possible to more effectively suppress the peeling or lifting. In the polarizing plate of the present invention, the adhesive force (plane, 23 DEG C) to the glass is more preferably 3.0 N / 25 mm or more, particularly preferably 4.0 N / 25 mm or more.

Further, the polarizing plate of the present invention is characterized in that the adhesive force (hereinafter referred to as &quot; adhesive force (curved surface, 23 DEG C) to glass] of the pressure sensitive adhesive layer measured in the curved surface state is 1.5 N / 25 mm or more , And further preferably 2.5 N / 25 mm or more. The adhesive force (curved surface, 23 DEG C) of the polarizing plate of the present invention is more preferably 3.5 N / 25 mm or more, and more preferably 4.5 N / 25 mm or more. The adhesive force to the glass measured in the curved surface state does not necessarily become the same as the adhesive force to the glass measured in the planar state and does not change with a certain rule such as a simple proportional relationship. Since the polarizing plate of the present invention is used in a curved image display apparatus, controlling the adhesive force of the curved surface state to the glass to be within a certain range means that the adhesive force of the polarizing plate to the glass, The control of the adhesive force to the image display element of the polarizing plate in a state of being in actual use is further advanced. In particular, if the adhesive force (curved surface, 23 ° C) to the glass is 1.5 N / 25 mm or more, and moreover 2.5 N / 25 mm or more, the polarizing plate is mounted on the curved image display panel, A sufficient adhesion to the image display panel can be ensured even in a harsh environment such as a case where the liquid crystal display panel is exposed to heat of the liquid crystal display panel or transportation under a high temperature and humidity environment and peeling or lifting of the polarizing plate from the curved image display panel It gets harder.

(Planar, 23 ° C) and adhesive force (curved surface, 23 ° C) to the glass of the polarizing plate of the present invention are both sufficient to ensure sufficient adhesion to the image display panel in a long term and / It is preferably 2.0 N / 25 mm or more, more preferably 3.0 N / 25 mm or more, and particularly preferably 4.0 N / 25 mm or more.

On the other hand, in the manufacturing process of the curved image display panel, in the case where a compounding mistake occurs when the polarizing plate is applied to the image display device or after the polarizing plate is attached to the image display device, The panel is peeled and reused), but it is also assumed that rework is performed in a curved surface state. In the case of rework in the curved state, in addition to the compressive stress already applied due to the curved state, additional compressive stress is applied to peel the polarizing plate from the image display panel. Therefore, peeling of the polarizing plate from the curved image display panel tends to become technically difficult as compared with the rewiring in the planar state, and in particular, the higher the adhesive force of the polarizing plate, the more the load The compressive stress becomes large, so that defects such as breakage of the glass plate constituting the display panel at the time of peeling, for example, are likely to occur.

When the adhesive force to the glass is excessively high, lifting or peeling of the polarizing plate itself can not occur from the image display panel. However, since there is a possibility that the above-mentioned reworkability may occur, the polarizing plate of the present invention is measured It is preferably 20.0 N / 25 mm or less, more preferably 15.0 N / 25 mm or less, further preferably 10.0 N / 25 mm or less, particularly preferably 6.0 N / 25 mm or less. The adhesive force (curved surface, 23 DEG C) to the glass is preferably 20.0 N / 25 mm or less, more preferably 15.0 N / 25 mm or less, further preferably 10.0 N / 25 mm or less, And preferably 6.0 N / 25 mm or less.

When the upper limit of the adhesive force to each glass is within the above range, it is easy to rework the polarizing plate easily from the display panel in the case where a misalignment number of the polarizing plate is generated or found in the manufacturing process of the curved image display panel. From the viewpoint of reworkability, it is preferable that the adhesive force (plane, 23 ° C) to glass and the adhesive force (curved surface, 23 ° C) to glass are both 20.0 N / 25 mm or less in the present invention.

When the polarizing plate of the present invention comprises an adhesive layer, the adhesive force (plane, 23 DEG C) to the glass is 20.0 N / 25 mm or less, further 15.0 N / 25 mm or less, particularly 10.0 N / 25 mm, Even if N / 25 mm or less, particularly 4.0 N / 25 mm or less, satisfies the formula (1), so lift and peeling can be suppressed.

The polarizing plate cut to a predetermined size was attached to a flat glass substrate with the adhesive layer interposed therebetween, and subjected to an autoclave treatment. The adhesive force (plane, 23 ° C) For 24 hours, and then peeling the polarizing plate from the glass substrate at a predetermined rate in the direction of 180 DEG. As in the case of measuring the adhesive force (curved surface, 23 DEG C) to the glass, the test piece obtained by attaching the polarizing plate to a glass plate was measured with a test piece on a metal plate having a radius of curvature of 2500 mm And fixed at 23 DEG C and 50% RH for 24 hours in a fixed state, and then the polarizing plate is peeled off.

A more detailed method of measuring the adhesive force (plane, 23 DEG C) to glass and the adhesive force (curved surface, 23 DEG C) to glass is as described in the following examples.

In the polarizing plate of the present invention, the adhesive force (hereinafter referred to as &quot; adhesive force to glass (plane, 80 DEG C) &quot;) of the pressure-sensitive adhesive layer measured in the planar state after 250 hours at 80 deg. Is preferably 7.0 N / 25 mm or more, more preferably 9.0 N / 25 mm or more, and still more preferably 11.0 N / 25 mm or more. In the polarizing plate of the present invention, the adhesive force (hereinafter referred to as "adhesive force to glass (curved surface, 80 ° C.)") of the pressure-sensitive adhesive layer measured in a curved state after 250 hours at 80 ° C. in dry ) Is preferably 8.0 N / 25 mm or more, more preferably 10.0 N / 25 mm or more, and still more preferably 12.0 N / 25 mm or more. In addition, as the adhesive strength increases, the test piece is broken at the time of measurement, and the adhesive force to each glass measured after 250 hours at 80 캜 in dry state can not be measured as a numerical value. This is a particularly preferred embodiment of the present invention.

When the adhesive force to each glass measured after 250 hours in a dry condition at 80 캜 is the same value as above, a sufficient adhesive force to the display panel can be ensured even in use for a long period of time and / or a high temperature environment, It is difficult to peel off or peel off. In the polarizing plate having the adhesive force (plane, 23 DEG C) to the above-described glass of the above-mentioned range, the adhesive force to each glass measured after 250 hours at 80 DEG C in the dry state is as described above, Do.

The adhesive force (plane, 80 DEG C) to the glass is preferably 5.0 N / 25 mm or more, more preferably 7.0 N / 25 mm or more, more preferably 10.0 N / 25 mm or more, Mm or more is particularly preferable. The adhesive force (curved surface, 80 DEG C) to the glass is preferably 5.0 N / 25 mm or more higher than the adhesive force (curved surface, 23 DEG C) to the glass, more preferably 7.0 N / 25 mm or higher, / 25 mm or more is particularly preferable. In the polarizing plate having the above-described adhesive force (plane, 23 ° C) against the above-described glass of a predetermined range, the adhesive strength to each glass measured after 250 hours at 80 ° C under dry conditions was 23 ° C and 50% In the initial state of bonding after being adhered to the image display element, the adhesion to the image display device can be increased and the adhesiveness required for use in a low-temperature environment from room temperature can be ensured, . Further, sufficient adhesion to the display panel can be ensured even in the case of exposure to heat of a light source for a long time, transportation in a high temperature and high humidity environment for a long time, and also in use for a long period and / or a high temperature environment, It becomes difficult to peel off or peel off.

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

The adhesive force (curved surface, 80 DEG C) to the glass is preferably 5.0 N / 25 mm or more, more preferably 7.0 N / 25 mm or more, more preferably 10.0 N / 25 mm or more, Mm or more is particularly preferable. If the difference between the adhesive force (curved surface, 80 DEG C) to glass and the adhesive force (plane, 23 DEG C) to glass is within the above range, the fusion and rework in the planar state can be facilitated, Sufficient adhesion to the display panel can be ensured even in use and the like, and peeling and lifting of the curved surface from the display panel are less likely to occur.

The adhesive force (plane, 80 ° C) to the glass and the adhesive force (curved surface, 80 ° C) to the glass were determined by measuring the adhesive force (plane, 23 Lt; 0 &gt; C) and adhesion to glass (curved surface, 23 [deg.] C).

The adhesive force of the adhesive layer to the glass varies depending on the kind of the component constituting the adhesive layer, the content ratio thereof, the forming conditions (drying, activation energy ray irradiation conditions), the thickness after the formation, Accordingly, the constituent components, the content ratio, the forming conditions, the thickness, and the like of the adhesive layer may be appropriately selected. Specifically, for example, an acrylic resin is used as a constituent component of a pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, a compound of a silane compound, and a pressure-sensitive adhesive layer Can be increased. Further, by changing the kinds and ratios of the monomers constituting the acrylic resin, the kind of the silane compound and the content thereof, the adhesive force to the glass can be controlled to a desired value.

<Polarizing Film>

The polarizing film that can constitute the polarizing plate of the present invention is a film having a function of drawing out linearly polarized light from incident natural light, and for example, a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and aligned can be used . As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, one obtained by saponifying a polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymer). Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified. For example, polyvinyl formal, polyvinyl acetal, and polyvinyl butyral modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000.

Such a polyvinyl alcohol-based resin film can be used as a polarizing film raw film. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventionally known method. The film thickness of the fabric film made of the polyvinyl alcohol-based resin is not particularly limited, but it is preferably 10 to 150 占 퐉, preferably 15 to 100 占 퐉, more preferably 20 to 100 占 퐉, 80 탆.

The polarizing film is usually produced by a process of uniaxially stretching a polyvinyl alcohol based resin film such as a polyvinyl alcohol film, a process of adsorbing a dichroic dye by dyeing the polyvinyl alcohol based resin film with a dichroic dye, A step of treating the adsorbed polyvinyl alcohol based resin film with an aqueous solution of boric acid, and a step of washing with water after treatment with an aqueous solution of boric acid. It is preferable from the industrial point of view to use a stretched and stained polyvinyl alcohol film thus produced as a polarizing film. The stretched and dyed polyvinyl alcohol film is a stretched polyvinyl alcohol film (adsorbed) containing a dichroic dye and the stretching magnification is as follows.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be carried out before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. In the case where uniaxial stretching is carried out after dyeing, this uniaxial stretching may be carried out before the boric acid treatment or during the boric acid treatment. The uniaxial stretching may be carried out in these plural stages. During uniaxial stretching, the film may be uniaxially stretched between rolls having different peripheral velocities, or uniaxial stretching may be performed using hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or may be a wet stretching in which stretching is performed in a state where the polyvinyl alcohol based resin film is swollen with a solvent. The stretching ratio is preferably 8 times or less, more preferably 7.5 times or less, and even more preferably 7 times or less from the viewpoint of suppressing deformation of the polarizing film. The stretching magnification is usually 4.5 times or more from the viewpoint of developing a function as a polarizing film.

As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, there is a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, for example, iodine or a dichroic dye is used. Dichroic dyes include dichromatic direct dyes composed of disazo compounds such as, for example, C. I. DIRECT RED 39, dichromatic direct dyes consisting of trisazo, tetrakisazo compounds and the like. It is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol resin film is dipped in an aqueous solution containing iodine and potassium iodide is generally used. The content of iodine in this aqueous solution is usually 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually 0.5 to 20 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 占 폚, and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1800 seconds.

When a dichroic dye is used as the dichroic dye, a method in which a polyvinyl alcohol resin film is dipped in an aqueous solution containing a water-soluble dichroic dye is generally employed. The content of the dichroic dye in the aqueous solution is usually 1 × 10 ^-4 to 10 mass parts, preferably 1 × 10 ^-3 to 1 mass parts, and more preferably 1 × 10 ^-3 To 1 x 10 &lt; ^-2 &gt; parts by mass. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. When a dichroic dye is used as the dichroic dye, the dye aqueous solution used for dyeing usually has a temperature of 20 to 80 ° C, and the dipping time (dyeing time) in this aqueous solution is usually 10 to 1,800 seconds.

The boric acid treatment after dyeing with the dichroic dye can be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid. The amount of boric acid in the aqueous solution containing boric acid is usually 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by mass, and preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersing time in the boric acid-containing aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 占 폚 or higher, preferably 50 to 85 占 폚, and more preferably 60 to 80 占 폚.

The polyvinyl alcohol-based resin film after treatment with boric acid is usually washed with water. The water washing treatment can be carried out, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of the water in the water washing treatment is usually 5 to 40 占 폚, and the immersion time is usually 1 to 120 seconds. After washing with water, drying treatment is carried out to obtain a polarizing film. The drying treatment can be carried out using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually 30 to 100 占 폚, preferably 40 to 95 占 폚, more preferably 50 to 90 占 폚. The drying treatment time is usually 60 to 600 seconds, preferably 120 to 600 seconds.

Thus, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a polarizing film. The thickness of the polarizing film may be, for example, 5 to 40 탆.

Since the coating type thin film polarizing film has a smaller dimensional change rate as compared with the polarizing film obtained by stretching a conventionally known polyvinyl alcohol type resin film, the coating type thin film polarizing film can be used for a long period of use and / The dimensional change of the polarizer can be suppressed. And can contribute to the thinning of the polarizing plate, which is preferable in the present invention. As the coating type thin film polarizing film, there can be used, for example, those exemplified in Japanese Patent Application Laid-Open Nos. 2001-58381, 2013-37115, 2012/147633, and International Publication No. 2014/091921 .

<Protective layer>

In a preferred embodiment, the polarizing plate of the present invention has a protective layer laminated on one side or both sides of the polarizing film. The polarizing plate of the present invention preferably has a protective layer in that the protective layer contributes to prevention of shrinkage and expansion of the polarizing film, deterioration of the polarizing film due to temperature, humidity, ultraviolet rays and the like.

The material for forming the protective layer is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like. For example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose polymer such as diacetylcellulose or triacetylcellulose, an acrylic polymer such as polymethyl methacrylate, a polystyrene or an acrylonitrile styrene copolymer (AS resin), and polycarbonate-based polymers. In addition, a polyolefin-based polymer such as polyethylene, polypropylene, a cyclo- or norbornene-based structure, a polyolefin-based polymer such as an ethylene-propylene copolymer, an amide-based polymer such as a nylon or an aromatic polyamide, Based polymers, polyether sulfone-based polymers, polyetheretherketone-based polymers, polyphenylene sulfide-based polymers, vinyl alcohol-based polymers, vinylidene chloride-based polymers, vinyl butyral-based polymers, arylate- An epoxy-based polymer, or a blend of the above-mentioned polymer may be mentioned as an example of the polymer forming the protective layer. The protective layer may be formed as a cured layer of a thermosetting resin such as an acrylic resin, a urethane resin, an acryl urethane resin, an epoxy resin, a silicone resin, or the like, or an ultraviolet curable resin. Among them, those having a hydroxyl group having reactivity with an isocyanate crosslinking agent are preferable, and a cellulose-based polymer is particularly preferable. The thickness of the protective layer is not particularly limited, but is generally 500 탆 or less, preferably 1 to 300 탆, more preferably 5 to 200 탆, and still more preferably 30 to 100 탆. The protective layer may be composed of a transparent protective film to which an optical compensation function is added. It is also preferable that the thickness of the outer protective layer laminated on the back side of the polarizing film is equal to the thickness of the inner protective layer laminated on the viewer side of the polarizing film or that the outer protective layer is thicker than the inner protective layer. By doing so, curling of the outer and inner protective layers is suppressed particularly when heat is applied to the polarizing plate, or curling is performed on the side of low rigidity, so that peeling and lifting from the display panel are unlikely to occur. This is particularly preferably applied on the concave side.

Since the shrinkage of the polarizing film can be suppressed by increasing the rigidity of the protective layer adjacent to the polarizing film, it is possible to suppress the dimensional change of the polarizing plate by controlling the rigidity of the protective layer. Here, the rigidity refers to a value obtained by multiplying the film thickness by the tensile modulus (23 ° C elasticity) at room temperature (23 ° C) of the film used for the protective layer and the tensile elastic modulus (80 ° C elasticity) . In particular, by increasing the stiffness obtained by multiplying the elastic modulus at 80 占 폚 by the film thickness, it is possible to suppress the dimensional change of the polarizing plate under a high temperature environment. For example, the cellulose polymer represented by triacetyl cellulose preferably has an elastic modulus at 23 占 폚 of 3000 to 5000 MPa and an elastic modulus at 80 占 폚 of 2000 to 4000 MPa, and the acrylic polymer represented by polymethyl methacrylate , The 23 ° C elastic modulus is 2000 to 4000 MPa and the 80 ° C elastic modulus is 800 to 2500 MPa. The polyolefin polymer having a norbornene structure preferably has an elastic modulus at 23 ° C of 2000 to 4000 MPa, an elastic modulus at 80 ° C of 1500 To 3000 MPa.

The surface of the protective layer that does not adhere to the polarizing film may have a surface treatment layer and may have an optical layer such as a hard coat layer, an antireflection layer, a sticking prevention layer, an antiglare layer, or a diffusion layer.

The hard coat layer is intended to prevent the occurrence of scratches on the surface of the polarizing plate. For example, the hard coat layer may be formed by a method of adding a cured film having excellent hardness, slipperiness, etc., to the surface of the protective layer by an ultraviolet curable resin such as acrylic or silicone . The antireflection layer is intended to prevent reflection of external light on the surface of the polarizing plate and can be achieved by forming a conventional antireflection film or the like. The anti-sticking layer is intended to prevent adhesion to the adjacent layer.

The anti-glare layer is for the purpose of preventing external light from being reflected from the surface of the polarizing plate and preventing the visible light from being transmitted through the polarizing plate. For example, the anti-glare layer is roughened by sandblasting or embossing Or by adding a fine concavo-convex structure to the surface of the protective layer by a method such as a blending method of transparent fine particles or the like. Examples of the fine particles contained for the formation of the surface micro concavo-convex structure include conductive particles made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide and antimony oxide having an average particle diameter of 0.5 to 50 탆 Organic fine particles made of inorganic fine particles, crosslinked or uncrosslinked polymers, and the like. In the case of forming the surface micro concavo-convex structure, the content of the fine particles is usually 2 to 50 parts by mass, preferably 5 to 25 parts by mass relative to 100 parts by mass of the transparent resin forming the surface micro concavo-convex structure. The anti-glare layer may also serve as a diffusion layer (time magnification function or the like) for diffusing the polarized-plate transmitted light to enlarge the viewing angle or the like. In addition, the protective layer may contain known additives if necessary. Examples of the additive include an ion trap agent, an antioxidant, a sensitizer, a light stabilizer, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, a defoamer, a dye, an antistatic agent and an ultraviolet absorber.

The antireflection layer, anti-sticking layer, diffusion layer, anti-glare layer, and the like may be formed on the protective layer itself and integrated, or may be formed as a separate optical layer separate from the protective layer.

<Adhesive Layer>

The polarizing film and the protective layer are usually bonded together with an adhesive. The adhesive for bonding the polarizing film and the protective layer is not particularly limited, but from the viewpoint of thinning the formed adhesive layer, it is preferable to use an aqueous adhesive, that is, an adhesive component dissolved in water, or an adhesive component dispersed in water . For example, an adhesive containing a polyvinyl alcohol resin or a urethane resin may be used as an adhesive component. When the polarizing film has a protective layer on both surfaces thereof, the adhesive used for the adhesion may be the same or different.

When the polyvinyl alcohol-based resin is contained as the adhesive component, the polyvinyl alcohol-based resin may be a partially saponificated polyvinyl alcohol, a fully saponified polyvinyl alcohol, a carboxyl group-modified polyvinyl alcohol, an acetoacetyl group-modified polyvinyl alcohol, Or a modified polyvinyl alcohol-based resin such as polyvinyl alcohol and amino group-modified polyvinyl alcohol. Normally, an adhesive containing a polyvinyl alcohol-based resin as an adhesive component is prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass based on 100 parts by mass of water.

The adhesive containing a polyvinyl alcohol-based resin as an adhesive component preferably contains a curing component such as glyoxal and water-soluble epoxy resin and / or a crosslinking agent in order to improve the adhesiveness. As the water-soluble epoxy resin, for example, epichlorohydrin is reacted with a polyamide amine obtained by the reaction of a polyalkylene polyamine such as diethylene triamine or triethylene tetramine with a dicarboxylic acid such as adipic acid A polyamide polyamine epoxy resin obtained by subjecting a polyisocyanate to a polymerization reaction. Examples of commercially available products of such polyamide polyamine epoxy resins include Sumirez Resin 650 (Sumika Chemtex Co., Ltd.), Sumirez Resin 675 (manufactured by Sumika Chemtex Co., Ltd.), WS-525 Manufactured by PMC Corporation). The amount of the curing component and / or the crosslinking agent to be added (when added together, the total amount thereof) is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol-based resin. When the addition amount of the curable component and / or the cross-linking agent is within the above range, the adhesiveness is improved and an adhesive layer exhibiting good adhesiveness can be formed.

When a urethane resin is contained as an adhesive component, it is preferable to use a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group. Here, the polyester-based ionomer-type urethane resin is a urethane resin having a polyester skeleton, and a small amount of ionic components (hydrophilic components) are introduced into the skeleton thereof. Such an ionomeric urethane resin is preferable as an aqueous adhesive since it emulsifies in water directly without using an emulsifier. The polyester-based ionomer-type urethane resin itself is known, and Japanese Unexamined Patent Publication No. 7-97504, for example, discloses an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium, Japanese Patent Application Laid-Open No. 2005-70140 and Japanese Patent Application Laid-Open No. 2005-208456 disclose a method in which a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group is used as an adhesive and a polarizing film made of a polyvinyl alcohol- And a form in which a cycloolefin-based resin film is laminated is shown.

The application of the adhesive to the polarizing film and / or the protective layer (protection film) to be adhered to the polarizing film can be carried out by a known method and can be carried out by a known method such as a casting method, a Meyer bar coating method, A comma coater method, a doctor blade method, a die coat method, a dip coat method, a spray method, or the like. The flexible method is a method of spreading an adhesive on a surface of a film to be coated, while moving the film in a generally vertical direction, a generally horizontal direction, or an inclined direction between the two. After the adhesive is applied, the polarizing film and the protective layer to be adhered to the polarizing film are superimposed, and the film is put in between by nip rolls or the like. The nip rolls may be formed by a method of applying an adhesive, spreading the film uniformly by spreading it with a roll or the like, spreading an adhesive, passing the film through a roll and a roll, . In this case, the material of the roll to be used may be metal or rubber. When the film passes through a plurality of rolls and spreads out, the plurality of rolls may be the same material or different materials.

The surface of adhesion between the polarizing film and the protective layer may be subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, saponification treatment and the like appropriately in order to improve adhesion. As the saponification treatment, a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide may be mentioned.

After the bonding, the adhesive is cured by drying to obtain a polarizing plate. This drying treatment is carried out, for example, by blowing hot air, and the temperature is usually in the range of 40 to 100 占 폚, preferably in the range of 60 to 100 占 폚. The drying time is usually 20 to 1200 seconds.

The thickness of the adhesive layer formed by the adhesive after drying is usually 0.001 to 5 占 퐉, preferably 0.01 to 2 占 퐉, more preferably 0.01 to 1 占 퐉. When the thickness of the adhesive layer is within the above range, it is preferable for the polarizing plate of the present invention, since sufficient adhesion can be ensured and it is also preferable from the viewpoints and it can contribute to thinning of the polarizing plate.

After drying, the curing may be carried out at room temperature or more for at least half a day, preferably several days or more, to obtain sufficient bonding strength. The curing temperature is preferably in the range of 30 to 50 占 폚, and more preferably in the range of 35 to 45 占 폚. If the curing temperature is within the above range, the so-called &quot; winding-tightening &quot; The humidity at the time of curing is not particularly limited, and the relative humidity may be in the range of 0 to 70% RH. The curing time is usually 1 to 10 days, preferably 2 to 7 days.

Further, a photo-curable adhesive may be used as the adhesive. Examples of the photocurable adhesive include a mixture of a photocurable epoxy resin and a photocathon polymerization initiator, and a mixture of a photocurable acrylic resin and a photocatalytic polymerization initiator. When a photocurable adhesive is used, the photocurable adhesive is cured by irradiating an active energy ray. A light source of an active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, a low energy mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, Mercury lamp, metal halide lamp and the like are preferable.

The light irradiation intensity for the photo-curable adhesive is appropriately determined according to the composition of the photo-curable adhesive and is not particularly limited, but the irradiation intensity in the wavelength range effective for activation of the polymerization initiator is preferably 0.1 to 6000 m / 10 to 1000 mW / cm &lt; 2 &gt;, more preferably 20 to 500 mW / cm &lt; 2 &gt;. When the irradiation intensity is within the above range, the reaction time can be ensured and deterioration of the yellowing of the epoxy resin and the deterioration of the polarizing film due to heat radiated from the light source and heat generation at the time of curing of the photocurable adhesive can be suppressed. The light irradiation time for the photo-curable adhesive is appropriately selected according to the photo-curable adhesive to be cured, and is not particularly limited. However, the cumulative light quantity as a product of the irradiation intensity and the irradiation time is preferably 10 to 10,000 mJ / , More preferably 50 to 1000 mJ / m 2, and further preferably 80 to 500 mJ / m 2. When the total amount of light for the photo-curing adhesive is within the above range, a sufficient amount of active species originating from the polymerization initiator is generated, the curing reaction can be more surely proceeded, and the irradiation time is not excessively long, and good productivity can be maintained .

Further, when the photocurable adhesive is cured by irradiation of active energy rays, it is possible to cure the photocurable adhesive, for example, when the polarizing plate of the polarizing plate, such as the polarizing degree, transmittance and hue of the polarizing film and transparency of various films constituting the protective layer and the optical layer, It is preferable to perform the curing under the condition that the function is not deteriorated.

&Lt; Optical layer &

The polarizing plate of the present invention may further include an optical layer such as a retardation film, a time compensating film and a luminance improving film, if necessary.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an orientation film of a liquid crystal polymer, and a film in which an orientation layer of a liquid crystal polymer is supported by a film. The stretching treatment can be carried out by, for example, a roll stretching method, a stretching method along a long gap, a tenter stretching method, a tubular stretching method and the like. The draw ratio is generally 1.1 to 3 times in the case of uniaxial drawing. The thickness of the retardation film is not particularly limited, but is usually 10 to 200 占 퐉, preferably 20 to 100 占 퐉.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, poly A polyolefin having a norbornene structure, a polyolefin such as polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, Vinyl, cellulose-based polymers, and binary, ternary copolymers, graft copolymers, and blended materials thereof. These polymer materials become oriented products (stretched films) by stretching or the like.

As the liquid crystal polymer, for example, various kinds of main chain type or side chain type polymers in which linear conjugated atomic groups (mesogens) for imparting liquid crystal alignability are introduced into the main chain or side chain of the polymer can be mentioned. Specific examples of the main chain type liquid crystal polymer include a nematic-oriented polyester-based liquid crystal polymer having a structure in which a mesogen group is bonded in a spacer portion imparting flexibility, a discotic polymer and a cholesteric polymer, have. As specific examples of the side chain type liquid crystal polymer, polysiloxane, polyacrylate, polymethacrylate or polymalonate is used as the main chain skeleton, and a spacer portion made of a conjugated atomic group as a side chain is interposed between the nematic- And those having a mesogen portion comprising a para-substituted cyclic compound unit. These liquid crystal polymers can be obtained, for example, by subjecting a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate to rubbing treatment, a liquid crystal polymer on the oriented surface such as silicon oxide by oblique deposition, Followed by heat treatment.

The retardation film may be any retardation film that has a retardation depending on the intended use such as various wavelength plates or those intended to compensate for coloring due to birefringence of the liquid crystal layer or for the purpose of visual observation or the like and may be formed by laminating two or more kinds of retardation films, Or the like may be used.

The time-compensating film is a film for widening the viewing angle so that the image appears relatively clear even when viewing the screen of the liquid crystal display device from a slightly inclined direction with respect to the screen. Such a time-compensating film includes, for example, an orientation film such as a retardation film or a liquid crystal polymer, or an orientation film such as a liquid crystal polymer supported on a transparent substrate. A conventional retardation film uses a polymer film having birefringence uniaxially stretched in its plane direction, whereas the retardation film used as a viewing retardation film includes a birefringent polymer film stretched biaxially in the plane direction, Direction stretched film such as a polymer having birefringence in which the refractive index in the thickness direction is controlled and an oblique orientation film stretched in the thickness direction, and the like are used. Examples of the oblique oriented film include those obtained by bonding a heat shrinkable film to a polymer film and stretching and / or shrinking the polymer film under the action of the shrinking force by heating, and those obtained by obliquely aligning the liquid crystal polymer have. As the material raw material polymer of the retardation film, the same polymer as that described in the retardation film is used, and for the purpose of preventing coloration due to a change in viewing angle based on the retardation caused by the liquid crystal cell, and enlarging the viewing angle with good visibility You can select and use it appropriately.

Further, from the viewpoint of achieving a wide viewing angle with good visibility, a time-compensating film in which an optically anisotropic layer composed of an alignment layer of a liquid crystal polymer, in particular, an oblique alignment layer of a discotic liquid crystal polymer, is supported by a triacetylcellulose film is preferably used.

The polarizing plate in which the polarizing plate and the brightness enhancing film are laminated is usually provided on the back side of the liquid crystal cell. Since the brightness enhancement film reflects linearly polarized light of a predetermined polarization axis or circularly polarized light in a predetermined direction when natural light is incident due to reflection from a backlight or a back side of a liquid crystal display device or the like and transmits the other light, A polarizing plate in which a film is laminated with a polarizing plate receives light from a light source such as a backlight to obtain transmission light in a predetermined polarized state and reflects light other than the predetermined polarized state without being transmitted. The light reflected from the surface of the brightness enhancement film is also reversed by reversing the reflective layer formed on the back side and re-entering the brightness enhancement film to transmit a part or the whole of the light as the light in the predetermined polarization state, It is possible to improve the luminance by supplying an amount of polarized light which is difficult to be absorbed by the polarizing film and by increasing the amount of light usable for liquid crystal image display and the like. That is, when light is incident through the polarizing film from the rear side of the liquid crystal cell by using a backlight or the like without using a brightness enhancement film, light having a polarization direction which does not coincide with the polarization axis of the polarizing film, And is not transmitted through the polarizing film. That is, although approximately 50% of the light is absorbed by the polarizing film, depending on the characteristics of the polarizing film used, the amount of light usable for liquid crystal image display and the like is reduced and the image is darkened. The brightness enhancement film does not cause the light having the polarization direction to be absorbed by the polarizing film to be incident on the brightness enhancement film while being reflected by the brightness enhancement film while being reversed through a reflection layer or the like formed on the back thereof The polarization direction of the light reflected and inverted between the polarized light and the polarized light is transmitted through only the polarized light that can pass through the polarizing film so as to be supplied to the polarizing film so that the light such as the backlight can be efficiently transmitted to the polarizing film So that the screen can be brightened.

The polarizing plate of the present invention can be produced, for example, by stacking a protective layer on a polarizing film with an adhesive and forming an adhesive layer on the surface of the protective layer on the side where the image display element is adhered. 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 by an adhesive, and an adhesive layer is formed on the surface opposite to the surface bonded to the protective layer do. The polarizing plate obtained by laminating the respective films and layers constituting the polarizing plate is curved so as to have a desired radius of curvature before being adhered to the image display device to obtain the polarizing plate of the present invention. In addition, it is also possible to form a curved surface after bonding with the image display element.

With respect to bonding with an image display element, for example, when used in a curved liquid crystal display panel, the polarizing plate of the present invention may be applied to a liquid crystal cell serving as an image display element through an adhesive layer. When used in a curved organic EL panel, the polarizing plate of the present invention may be applied to a visible side display surface of an organic EL display device, which is an image display device, with an adhesive layer interposed therebetween.

In the case of a liquid crystal display panel, for example, in the case of a liquid crystal display panel, the laminated body of the image display element, the concave surface side and the convex surface side polarizing plate is fixed to the frame with a predetermined radius of curvature, Or by laying the laminate on a curved backlight unit with a predetermined radius of curvature, and then pressing the laminate from above with a frame.

The polarizing plate of the present invention can be used as a polarizing plate of a curved image display panel such as a curved liquid crystal panel or a curved organic EL panel, particularly as a polarizing plate of a curved liquid crystal display panel. In the curved image display panel, since the image display panel is curved, a compressive stress is always generated. Since the compressive stress is larger at the concave surface side (viewing side), the size of the polarizing plate positioned on the concave surface side tends to change easily. On the other hand, since the image display element for attaching the polarizing plate is generally sandwiched by the glass substrate, And it is considered that a difference in shrinkage ratio is likely to occur between the concave-surface-side polarizing plate and the image display device. Therefore, on the concave surface side of the curved image display panel, peeling or lifting of the polarizing plate tends to occur particularly. The polarizing plate of the present invention can be used as any of the concave-side polarizing plate and the convex-plane-side polarizing plate constituting the curved image display panel. However, since the polarizing plate has a high suppressing effect on the peeling and peeling in the curved surface state, And is preferably used as a concave-surface-side polarizer mounted on the concave surface side. That is, in one embodiment of the present invention, there is provided a curved image display panel comprising a concave surface side polarizing plate and a convex surface side polarizing plate, wherein the concave surface side polarizing plate is a polarizing plate of the present invention. In another embodiment of the present invention, there is provided a curved image display panel comprising a concave surface side polarizing plate and a convex surface side polarizing plate, wherein the concave surface side polarizing plate and the convex surface side polarizing plate are polarizing plates of the present invention.

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 surface side polarizing plate are arranged so that the absorption axis directions (stretching directions) of the polarizing films included in these polarizing plates are orthogonal to each other. For example, as shown in Fig. 4, when 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. As shown in Fig. 5, when the absorption axis direction of the polarizing film included in the concave-side polarizing plate is vertical, the absorption axis direction of the polarizing film included in the convex-side polarizing plate is the horizontal direction. The absorption axis direction of the polarizing film included in the concave surface side polarizing plate may be a vertical direction, a horizontal direction, or an angular direction of 45 degrees with respect to the horizontal direction. In most of the image display panel products, the absorption axis direction of the polarizing film included in the concave-side polarizing plate is in the horizontal direction. In particular, in this case, deformation such as shrinkage of the polarizing plate tends to occur, and peeling or lifting of the polarizing plate tends to occur. Has been found in the invention. According to the polarizing plate of the present invention, even if the direction of the absorption axis is in the horizontal direction, the occurrence of scratches on the surface of the polarizing plate can be suppressed, and the above problems can be solved.

The polarizing plate of the present invention can be preferably used for a curved image display panel having various screen sizes. For example, it is possible to use a 5 inch (horizontal length: 100 to 150 mm), 10 inch (horizontal length: 200 to 250 mm), 17 inch (horizontal length: 320 to 400 mm) (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) (Length: 1400 to 1450 mm), 75 inches (horizontal length: 1600 to 1700 mm), and 85 inches (horizontal length: 1800 to 1900 mm). The larger the screen size, the larger the size of each constituent member, the compressive stress acts on the concave-side polarizer in the curved state, and the discrepancy between the sizes of the polarizer and the image display element occurs, . In an image display apparatus having a screen aspect ratio (vertical length: horizontal length) of 3: 4, it is difficult for the polarizing plate to be peeled off or lifted. However, when the aspect ratio of the screen is 9: 13 to 9: 23, preferably 9 : 15 or more, and more preferably 9: 19 or less. For example, in a horizontally elongated image display panel of 9: 16 or 9: 21, compressive stress acts on the concave- It has been found by the present inventors that the polarizing plate and the image display element are inconsistent in size and the polarizing plate is likely to be peeled or lifted. Since the polarizing plate of the present invention has a high suppressing effect on peeling and peeling in a curved surface state, it is preferably used as a polarizing plate for various screen sizes, particularly a relatively large screen size or a horizontally long curved image display panel .

The curved image display panel of the present invention including the polarizing plate of the present invention is excellent in the effect of suppressing the peeling and lifting of the polarizing plate from the 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

(Trade name "VF-PE # 6000", manufactured by Kuraray Co., Ltd.) having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more was impregnated with pure water at 30 ° C., And immersed in an aqueous solution having a mass ratio of potassium / water of 0.02 / 2/100 at 30 占 폚. Thereafter, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Subsequently, the film was washed with pure water at 8 캜 and dried at 80 캜 to obtain a polarizing film in which iodine adsorbed and oriented on a polyvinyl alcohol film. The stretching was carried out mainly during iodine dyeing and boric acid treatment, and the total stretching magnification was 6.0 times. The thickness of the obtained polarizing film was 22 탆.

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

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

(1) Acrylic resin film (2-A)

70% by mass of a methacrylic resin and 30% by mass of rubber particles were mixed with a super mixer, 2% by mass of a benzotriazole based ultraviolet absorber was added to 100% by mass of the mixture and melt kneaded by a twin screw extruder to obtain pellets. This pellet was put into a 65 mm single screw extruder, extruded through a T-die having a set temperature of 275 DEG C, and cooled by placing the film between two polishing rolls having mirror surfaces to obtain an 80 mu m thick acrylic resin film (2-A).

As the methacrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (by mass) was used. It is preferable that the innermost layer comprises a hard polymer obtained by polymerizing methyl methacrylate with a small amount of allyl methacrylate and the intermediate layer contains butyl acrylate as a main component and styrene and a small amount of allyl methacrylate Layered structure composed of a soft polymer polymerized by polymerization using a small amount of methyl acrylate and a hard polymer obtained by polymerizing methyl methacrylate with a small amount of ethyl acrylate and having an average particle diameter 240 nm. In this rubber particle, the total mass of the innermost layer and the intermediate layer was 70% of the whole particles.

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

On the acrylic resin film (2-A), hard coat treatment was carried out. The hard coat treatment was conducted in the same manner as in Example 1 except that the treatment solution (pentaerythritol triacrylate: 42.5 parts by mass, Irgacure 184: 0.25 parts by mass, silicone (leveling agent): 0.1 part by mass, silica (average particle diameter: 7.5 parts by mass of surface methacryloylmonomer silica (surface organic component: 4.05 x 10 ^-3 g / m 2) and 34 parts by mass of toluene), followed by drying and then irradiating with ultraviolet rays using an ultraviolet irradiator Respectively. Thus, an acrylic resin film (2-B) (total thickness: 85 탆) having a hard coat layer with a thickness of 5 탆 was obtained.

(3) TAC film (2-C)

A triacetyl cellulose film "KC6UAW" (thickness: 60 μm) manufactured by Konica Minolta Opto Corporation was used as the TAC film (2-C).

(4) TAC film (2-D)

On the (2-C) TAC film, a hard coat treatment was carried out in the same manner as in (2-B). Thus, a TAC film (2-D) (total thickness: 65 탆) having a hard coat layer with a thickness of 5 탆 was obtained.

(5) COP film (2-E)

A COP film (2-E) was used as a ring-shaped polyolefin biaxially oriented resin film "Zeonor film ZB12" (thickness: 52 μm) manufactured by Nippon Zeon Co.,

3. Preparation of adhesive

A UV-curable adhesive of a non-solvent type obtained by mixing the following components was used as an adhesive. Further,% represents the content (% by mass) when the total amount of the adhesive is 100 mass%.

-Cyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate ("Celloxide 2021P" manufactured by Daicel Chemical Industries, Ltd.): 80%

1,4-butanediol diglycidyl ether: 19%

A photocathione polymerization initiator (CPI-100P: propylene carbonate solution having an active ingredient of 50% as a main component and having triarylsulfonium hexafluorophosphate as a main component, manufactured by San A Pro Co., Ltd.) was used as a main ingredient of triarylsulfonium hexafluorophosphate CPI-100P &quot;): 1%

4. Preparation of adhesive

A reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer was charged with 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, 1.0 part by mass of ethyl and 0.6 part by mass of acrylic acid were charged, and the inside temperature was raised to 55 占 폚 while oxygen was removed by replacing air in the apparatus with nitrogen gas. Thereafter, a total amount of a solution obtained by dissolving 0.14 parts by mass of azobisisobutyronitrile as a polymerization initiator in 10 parts by mass of ethyl acetate was added. The temperature was maintained for 1 hour after the addition of the polymerization initiator, and then ethyl acetate was continuously added into the reaction vessel at an addition rate of 17.3 parts by mass / hour while the internal temperature was maintained at 54 to 56 ° C, and the concentration of the acrylic resin was 35 mass %, The addition of ethyl acetate was stopped. It was kept at this temperature for 12 hours from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the acrylic resin to 20% by mass. This was an acrylic resin.

The weight-average molecular weight and the number-average molecular weight of the obtained acrylic resin were measured according to the following methods. Four "TSKgel XL" manufactured by Tosoh Corporation and one "Shodex GPC KF-802" manufactured by Showa Denko Co., Ltd. were used as a column in the GPC apparatus, And measuring tetrahydrofuran in terms of standard polystyrene at a sample concentration of 5 mg / ml, a sample introduction amount of 100 占 퐇, a temperature of 40 占 폚, and a flow rate of 1 ml / min. The acrylic resin thus obtained had a weight average molecular weight Mw of 142,000 and an Mw / Mn of 4.1.

0.5 part by mass of glycidoxypropyltrimethoxysilane (liquid) (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 100 parts by mass of the solid content of the acrylic resin (20 mass% ), 0.6 part by mass of coronate HXR (isocyanurate of hexamethylene diisocyanate, liquid having an active ingredient of about 100% by mass, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and 3.0 parts by mass of N-octyl- Methylpyridinium hexafluorophosphate were mixed. Subsequently, ethyl acetate was added to give a solid content concentration of 13% by mass to obtain a pressure-sensitive adhesive.

Example 1

The film (2-D) and the film (2-E) which are the protective layers were subjected to corona treatment in advance using a corona processor (manufactured by Kasuga Electric Co., Ltd.), an adhesive was applied thereon, and the film was bonded to a polarizing film. Thereafter, ultraviolet rays were irradiated by a metal halide lamp to cure the adhesive. On the film (2-E) side, a layer of a pressure-sensitive adhesive of 20 m was formed to obtain a concave-side polarizer A having a thickness of 0.17 mm (excluding the separator film used for forming the pressure-sensitive adhesive layer).

A convex surface side polarizing plate B of a thickness of 0.16 mm (excluding a separator film used for forming an adhesive layer) was obtained in the same manner as above except that the film (2-C) was used in place of the film (2-D).

The polarizing plate A was cut into a size of 1215 mm in length (horizontal length) × 683 mm in length (vertical length), and the polarizing plate A was cut so that the absorption axis direction of the polarizing plate A was the transverse direction. The polarizing plate B was cut into a size of 1215 mm in width x 683 mm in length, and the polarizing plate B was cut so that the absorption axis direction of the polarizing plate B was the longitudinal direction. The cut polarizing plate A was laminated on the viewing side (concave side) of a glass panel having a width of 1215 mm and a length of 683 mm and a thickness of 1.5 mm and the cut polarizing plate B was bonded to the back side (convex surface side) of the panel . Thereafter, the glass panel was bent and fixed so as to have an average curvature radius of 4000 mm, and the glass panel was held at 80 deg. C in a dry state for 250 hours. After the lapse of 250 hours, the appearance of the panel was visually observed. As a result, no peeling or peeling of the polarizing plate occurred. The rate of dimensional change measured by the above method was 0.8%. At this time, L1 (H + H1) / 2R = 0.25.

Example 2

The film (2-B) and the film (2-E) which are the protective layers were subjected to corona treatment in advance using a corona processor (manufactured by Kasuga Electric Co., Ltd.), an adhesive was applied thereon, . Thereafter, ultraviolet rays were irradiated by a metal halide lamp to cure the adhesive. On the surface of the film (2-E), a layer of a pressure-sensitive adhesive of 20 m was formed to obtain a concave-side polarizer C having a thickness of 0.19 mm (excluding the separator film used for forming the pressure-sensitive adhesive layer).

A convex surface side polarizing plate D having a thickness of 0.18 mm was obtained in the same manner as above except that the film (2-A) was used instead of the film (2-B).

The polarizing plate C was cut into a size of 1215 mm in width x 683 mm in length, and the polarizing plate C was cut so that the absorption axis direction of the polarizing plate C was the transverse direction. The polarizing plate D was cut into a size of 1215 mm in width x 683 mm in length, and the polarizing plate D was cut so that the absorption axis direction of the polarizing plate D was the longitudinal direction. The cut polarizing plate C was stuck to the viewing side (concave side) of a glass panel having a width of 1215 mm and a length of 683 mm and a thickness of 1.5 mm and the cut polarizing plate D was bonded to the back side (convex side) of the panel . Thereafter, the panel was bent and fixed so as to have an average radius of curvature of 4000 mm, and kept at 80 캜 under dryness for 250 hours. After the lapse of 250 hours, the appearance of the panel was visually observed. As a result, no peeling or peeling of the polarizing plate occurred. The rate of dimensional change measured by the above method was 1.4%. At this time, L1 (H + H1) / 2R = 0.26.

Example 3

The polarizing plates C and D were cut into a size of 1440 mm in width and 810 mm in length and the polarizing plates C and D were bonded to a glass panel of 1440 mm in length x 810 mm in length and 1.5 mm in thickness, Except that the panel was bent and fixed to be 6600 mm in the same manner as in Example 2, peeling of the polarizing plate and removal of the polarizing plate were evaluated. As a result, a large peeling or peeling of the polarizing plate did not occur. The rate of dimensional change measured by the above method was 1.4%. At this time, L1 (H + H1) / 2R = 0.18.

Comparative Example 1

The evaluation of the peeling and peeling off of the polarizing plate in the curved surface panel was carried out in the same manner as in Example 2 except that the average curvature radius of the panel was 2500 mm. As a result, in the short side of the concave-side polarizing plate C, lifting from the glass occurred from the edge to 50 mm. The rate of dimensional change measured by the above method was 1.4%. At this time, L1 (H + H1) / 2R = 0.41.

Example 4

Except that the size of the polarizing plates C and D was cut into a size of 1440 mm in width x 810 mm in length and the polarizing plates C and D were bonded to a glass panel of 1440 mm in length x 810 mm in length and 1.5 mm in thickness, (H + H1) / 2R = 0.30 when the polarizing plate is peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 2, and the occurrence of a large peeling or lifting of the polarizing plate is suppressed.

Example 5

Except that the polarizing plates C and D were cut into a size of 1660 mm in width x 934 mm in length and the polarizing plates C and D were bonded to a glass panel of 1660 mm in length x 934 mm in length and 1.5 mm in thickness, As in the case of Example 2, evaluation of peeling and peeling off of the polarizing plate in the surfaced panel is L1 (H + H1) / 2R = 0.35, and the occurrence of a large peeling off and lifting of the polarizing plate is suppressed.

Example 6

The polarizing plates C and D were cut into a size of 900 mm in length and 506 mm in length, the polarizing plates C and D were bonded to a glass panel of 900 mm in length x 506 mm in length and 1.5 mm in thickness, (H + H1) / 2R = 0.30 when the polarizing plate was peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 2 except that the average curvature radius was 2500 mm. The occurrence of lifting is suppressed.

Example 7

The polarizing plates C and D were cut into a size of 508 mm in width and 286 mm in length. The polarizing plates C and D were bonded to a glass panel of 508 mm in length x 286 mm in length and 1.5 mm in thickness, (H + H1) / 2R = 0.17 when the polarizing plate was peeled off or peeled off in a curved surface panel in the same manner as in Example 2 except that the average curvature radius was 2500 mm. The occurrence of lifting is suppressed.

Comparative Example 2

(H + H1) / 2R = 0.49 when the polarizing plate was peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 4 except that the average curvature radius of the panel was 2500 mm. And the occurrence of lifting occurs.

Comparative Example 3

(H + H1) / 2R = 0.56 when the polarizing plate was peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 5 except that the average curvature radius of the panel was 2500 mm. And the occurrence of lifting occurs.

Comparative Example 4

(H + H1) / 2R = 0.76 when the polarizing plate was peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 6 except that the average curvature radius of the panel was 1000 mm. And the occurrence of lifting occurs.

Comparative Example 5

(H + H1) / 2R = 0.43 when the polarizing plate was peeled off or peeled off from the surface of the polarizing plate in the same manner as in Example 7 except that the average curvature radius of the panel was 1000 mm. And the occurrence of lifting occurs.

Example 8

The polarizing plates A and B were cut into a size of 1050 mm by 600 mm in length and the polarizing plates A and B were laminated on a glass panel having a width of 1050 mm and a length of 600 mm and a thickness of 1.5 mm and having an average radius of curvature Except that the panel was bent and fixed so as to have a thickness of 2500 mm, the peeling of the polarizing plate on the curved surface panel and the peeling off of the polarizing plate were evaluated. As a result, a large peeling or peeling of the polarizing plate did not occur. The rate of dimensional change measured by the above method was 0.8%. At this time, L1 (H + H1) / 2R = 0.35.

5. Evaluation of Adhesion to Glass

(1) Measurement of adhesion to glass

(a) &quot; adhesion to glass (plane, 23 캜) &quot; and &quot; adhesion to glass (curved surface, 23 캜)

Each sample of the test pieces for measuring the adhesive force to the glass in the planar state and the curved state produced in Example 1 and Example 2 was subjected to autoclave treatment at 50 캜 and 5 kg / cm 2 (490.3 ㎪, gauge pressure) for 20 minutes The glass panel and the polarizing plate were then chucked by using Autograph (AGS-50NX) manufactured by Shimadzu Corporation, and the glass panel and the polarizing plate were chucked, and they were rotated at a speed of 300 mm / minute in a 180 ° direction To thereby peel the polarizing plate. The peel strength thus measured was defined as "adhesion to glass (plane, 23 ° C)" and "adhesion to glass (curved surface, 23 ° C)". The results are shown in Table 1.

(b) Measurement of adhesive force (plane, 80 캜) to glass and adhesive force (curved surface, 80 캜) to glass

Each of the test pieces for measuring the adhesive force to the glass in the planar state and the curved state produced in Example 1 and Example 2 was subjected to 20 minutes of autolysis at 50 캜, 5 kg / cm 2 (490.3 ㎪, gauge pressure) After the clave treatment, the glass panel and the polarizing plate were allowed to stand at 23 DEG C and 50% RH for 24 hours, and then allowed to stand at 80 DEG C under a dry environment for 250 hours. Using the AGS- 50NX manufactured by Shimadzu Corporation, And each polarizing plate was peeled in the direction of 180 DEG at a speed of 300 mm / min. The thus measured peel strength was defined as &quot; adhesion to glass (plane, 80 DEG C) &quot; and &quot; adhesion to glass (curved surface, 80 DEG C) &quot;. The results are shown in Table 1.

1: concave surface side polarizing plate
2: convex surface side polarizer
3: Image display element
10: Adhesive layer
11: Protective layer
12: polarizing film
13: Surface treatment layer

Claims (9)

A polarizing plate used in a curved image display panel having an average curvature radius R (mm) and a thickness H (mm) and having a horizontal length L1 (mm) in a planar state,
The thickness H1 (mm) of the polarizer, which becomes the concave surface side when being adhered to the curved image display panel, satisfies the following formula (1):
L1 (H + H1) / 2R? 0.4 (1)
. The method according to claim 1,
Wherein the adhesive force to glass measured in a planar state at 23 占 폚 and 50% RH is 2.0 N / 25 mm or more. 3. The method according to claim 1 or 2,
And the horizontal length L1 of the polarizing plate in the planar state is 500 mm or more. 4. The method according to any one of claims 1 to 3,
And the thickness H of the curved image display panel is 0.4 mm or more. 5. The method according to any one of claims 1 to 4,
And a dimensional change rate after 250 hours at 80 占 폚 in a dry state of 3% or less. 6. The method according to any one of claims 1 to 5,
The polarizing film in the polarizing plate is a stretched and dyed polyvinyl alcohol film. 7. The method according to any one of claims 1 to 6,
Wherein the curved image display panel has an average curvature radius R of 900 to 7000 mm.  A concave surface side polarizing plate, and a convex surface side polarizing plate, wherein the concave surface side polarizing plate is the polarizing plate according to any one of claims 1 to 7. Wherein the concave surface side polarizing plate and the convex surface side polarizing plate are the polarizing plate according to any one of claims 1 to 7.

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