TWI732231B - Polarizing film, polarizing film with adhesive layer and image display device - Google Patents

Abstract

The object of the present invention is to provide a polarizing film which has a notch and/or a through hole, and even in a severe environment of thermal shock, the notch and the through hole are not prone to cracks. The polarizing film of the present invention is provided with a protective film on one or both sides of the polarizing member via an adhesive layer; the long side L of the outer edge of the polarizing film is 60~400mm and the short side W is 30~300mm, and the aforementioned polarizing film It has more than one special-shaped part, and the special-shaped part is selected from at least one of the notch part and the through hole; the notch part is provided on the outer edge of the polarizing film, and the shape of the notch part is a straight line, a curve or the like _{Combination structure; The angle θ 1} formed by the two straight lines forming the shape of the notch is 90° or more and less than 180°, and the radius of curvature R ₁ of the curve forming the shape of the notch is a specific size; the through hole It is set inside the plane of the polarizing film, and the shape of the through hole is composed of straight lines, curves, or a combination of these; the angle θ ₂ formed by the two straight lines forming the shape of the through hole is 90° or more and less than 180° _{, And the radius of curvature R 2} of the curve constituting the shape of the through hole is 0.6 mm or more.

Description

Polarizing film, polarizing film with adhesive layer and image display device

The present invention relates to a polarizing film and a polarizing film having an adhesive layer of the polarizing film and an adhesive layer. In addition, the present invention relates to an image display device including the aforementioned polarizing film or the aforementioned polarizing film with an adhesive layer.

Background of the invention In various image display devices, polarizing films are used to display images. For example, from the perspective of the image forming method of a liquid crystal display device (LCD), it is necessary to arrange polarizing films on both sides of the glass substrate forming the surface of the liquid crystal panel. On the organic EL display device, in order to shield the specular reflection of external light on the metal electrode, a circularly polarized film laminated with a polarizing film and a quarter-wave plate is arranged on the viewing side of the organic light-emitting layer.

The aforementioned polarizing film is generally used for a polarizer composed of a polyvinyl alcohol-based film and a dichroic material such as iodine, and a protective film is attached to one or both sides of the polarizer through a polyvinyl alcohol-based adhesive or the like.

The aforementioned polarizing film is subject to severe thermal shock (for example, repeated thermal shock tests at -40°C and 85°C). Due to the change in the shrinkage stress of the polarizer, it is easy to absorb the overall direction of the polarizer. The problem of cracks (penetrating cracks).

Patent Document 1 proposes a polarizing plate for the purpose of providing a polarizing plate with excellent durability even in a cold and thermal shock environment. The polarizing plate is formed by arranging transparent protective films on both sides of the polarizing film and is characterized by: The difference between the linear expansion coefficient of the polarizing film in the direction orthogonal to the absorption axis and the linear expansion coefficient of the transparent protective film arranged on at least one side of the polarizing film in the direction orthogonal to the absorption axis of the polarizing plate is 1.3× Below 10 ^-4 /℃.

Prior art literature Patent literature Patent Document 1: Japanese Patent Application Publication No. 2011-203571

Summary of the invention The problem to be solved by the invention In the past, the screens of mobile terminals such as smartphones were generally rectangular. However, in recent years, from the viewpoint of screen expansion and design, liquid crystal panels with irregular shapes have gradually become a trend. The special-shaped part of the LCD panel can be equipped with a main screen button and camera lens. It is expected that the demand for special-shaped LCD panels will increase in the future. In order to manufacture a liquid crystal panel with a deformed portion, a polarizing film with a deformed portion is necessary.

However, in a polarizing film with a deformed part, the stress due to expansion and contraction under the severe environment of thermal shock is likely to concentrate on the deformed part, and there is a problem that the deformed part is prone to cracks.

The object of the present invention is to provide a polarizing film which has a notch and/or a through hole, and the notch and the through hole are not prone to cracks even in a severe environment of thermal shock.

In addition, an object of the present invention is to provide an adhesive polarizing film with the aforementioned polarizing film and an adhesive layer, and an image display device including the polarizing film or the polarizing film with the adhesive.

Methods to solve the problem The inventors of the present invention have actively reviewed and found that the above-mentioned problems can be solved by the following polarizing film, and the present invention has been completed.

That is, the present invention relates to a polarizing film, which is provided with a protective film on one or both sides of a polarizer via an adhesive layer. The characteristic of the polarizing film is that the long side L of the outer edge of the polarizing film is 60 ~400mm and the short side W is 30~300mm, and the aforementioned polarizing film has more than one shaped part, and the shaped part is selected from at least one of the notch part and the through hole; the aforementioned notch part is provided on the outer edge of the polarizing film , And the shape of the notch is composed of straight lines, curves or a combination of these; the angle θ ₁ formed by the two straight lines constituting the shape of the notch is 90° or more and less than 180°, and the notch is located on the long side When L is up, the radius of curvature R _{1 of the} curve forming the shape of the notch satisfies the following formula (1), and when the notch is located on the short side W, the radius of curvature R _{1 of the curve forming the shape of the notch is} Satisfying the following formula (2), when the notch is located at the corner of the outer edge, the radius of curvature R ₁ of the curve forming the shape of the notch is 0.2 mm or more; the through hole is provided inside the plane of the polarizing film, and The shape of the through hole is composed of a straight line, a curve, or a combination of these; the angle θ ₂ formed by the two straight lines constituting the shape of the through hole is 90° or more and less than 180°, and constitutes the shape of the through hole The radius of curvature R ₂ of the curve is 0.6mm or more; R ₁ ＜(L ₁ -1)/2 (1) L ₁ ... the length of the notch on the long side L (mm), R ₁ ＜(W _1- 1)/2 (2) W ₁ ...The length of the notch on the short side W (mm).

The aforementioned notch is preferably provided in at least one of the aforementioned long side L, the aforementioned short side W, and the aforementioned outer edge corner.

In addition, the aforementioned L _{1 of the} aforementioned notch is preferably 100 to 200 mm, and the aforementioned W _{1 is} preferably 50 to 100 mm.

In addition, the maximum depth D _{1 of the} notch from the long side L is preferably 2 to 50 mm, and the maximum depth D _{2 of the} short side W is preferably 2 to 25 mm.

In addition, the aforementioned through holes are preferably circular, elliptical, rectangular with rounded corners, quadrangular or polygonal with five or more corners.

In addition, the thickness of the aforementioned polarizer is preferably 10 μm or less.

In addition, the present invention relates to a polarizing film with an adhesive layer having the aforementioned polarizing film and an adhesive layer.

In addition, the present invention relates to an image display device, in which the polarizing film or the polarizing film with the adhesive layer is disposed on the image display unit.

Invention effect Since the deformed part of the polarizing film of the present invention has the above-mentioned specific shape, under the severe environment of thermal shock, the stress due to expansion and contraction is not easy to concentrate on the deformed part. Therefore, it is not easy to produce cracks in the special-shaped part.

The form used to implement the invention 1. Polarizing film The polarizing film of the present invention is provided with a protective film on one or both sides of the polarizer through the adhesive layer, and the long side L of the outer edge of the polarizing film is 60~400mm and the short side W is 30~300mm (in addition, the length Side L>Short side W). The length of the long side L and the short side W can be adjusted appropriately according to the application of the polarizing film. For example, the long side L can be 100~200mm, and the short side W can be 50~100mm. In addition, the aforementioned polarizing film has one or more deformed portions, and the deformed portion is selected from at least one of the notch portion and the through hole.

The components are explained below.

(1) Polarizing parts The polarizing member can be used without any particular limitation. However, from the viewpoint of thinning and suppressing the occurrence of cracks, it is preferable to use a polarizing member with a thickness of 10 μm or less. The thickness of the polarizer is more preferably 8 μm or less, more preferably 7 μm or less, and even more preferably 6 μm or less. On the other hand, the thickness of the polarizer is 2 μm or more, more preferably 3 μm or more.

The polarizer is made of polyvinyl alcohol resin. Examples of polarizers include hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene-vinyl acetate copolymer-based partially saponified films that adsorb iodine or dichroic dyes. Color substances and uniaxially stretched ones, as well as polyene-based oriented films such as dehydrated polyvinyl alcohol or dehydrated polyvinyl chloride. Among them, a polarizer composed of a dichroic substance such as a polyvinyl alcohol-based film and iodine is more suitable.

The polarizer in which a polyvinyl alcohol-based film is dyed with iodine and uniaxially stretched can be produced by, for example, immersing polyvinyl alcohol in an aqueous solution of iodine for dyeing, and stretching it to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, etc., and may be immersed in an aqueous solution such as potassium iodide. Furthermore, if necessary, the polyvinyl alcohol-based film may be immersed in water for washing before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt and anti-caking agent on the surface of the polyvinyl alcohol-based film can be washed. In addition, it also has the effect of swelling the polyvinyl alcohol-based film to prevent uneven dyeing. Extension may be performed after dyeing with iodine, or may be extended while dyeing, or may be dyed with iodine after extension. It can also be extended in aqueous solutions such as boric acid or potassium iodide or in a water bath.

From the viewpoint of extension stability and humidification reliability, the polarizer should preferably contain boric acid. In addition, from the viewpoint of suppressing the generation of cracks, the content of boric acid contained in the polarizer is preferably 22% by weight or less, and more preferably 20% by weight or less with respect to the total amount of the polarizer. From the viewpoint of extension stability and humidification reliability, the content of boric acid relative to the total amount of the polarizer is preferably 10% by weight or more, and more preferably 12% by weight or more.

Examples of thin polarizers include: Japanese Patent No. 4751486 specification, Japanese Patent No. 4751481 Specification, Japanese Patent No. 4815544 Specification, Japanese Patent No. 5048120 Specification, International Publication No. 2014/077599 Bulletin Manual, The thin polarizer described in the manual of International Publication No. 2014/077636, etc., or the thin polarizer manufactured by the manufacturing method described in the same.

In the manufacturing method including the stretching step and the dyeing step in the state of a laminate, from the viewpoint of being able to stretch at a high magnification and improving the polarization performance, the aforementioned thin polarizer is described in Japanese Patent No. 4751486 and Japanese Patent No. 4751481. The specifications described in the specification of Japanese Patent No. 4815544 and the specification of Japanese Patent No. 4815544 are preferably obtained by the method including the step of extending in an aqueous solution of boric acid, and particularly as described in the specification of Japanese Patent No. 4751481 and the specification of Japanese Patent No. 4815544 It is preferably obtained by a manufacturing method that includes a step of auxiliary aerial stretching before stretching in a boric acid aqueous solution. These thin polarizers can be produced by a manufacturing method including the following steps: a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin substrate for stretching in the state of a laminate and dyeing step. As long as this method is used, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, so it can be stretched without causing problems such as breakage due to stretching.

(2) Protective film The material of the protective film is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy. Examples include: polyester-based polymers such as polyethylene terephthalate or polyethylene naphthalate; cellulose-based polymers such as diacetyl cellulose or triacetyl cellulose; polymethyl methacrylate Acrylic polymers such as esters; styrene polymers such as polystyrene or acrylonitrile-styrene copolymer (AS resin); polycarbonate polymers, etc. In addition, the following polymers can also be cited as examples of the polymers forming the above-mentioned protective film: polyethylene, polypropylene, polyolefins having cyclic or even norbornene structures, such as polyolefin polymers of ethylene-propylene copolymers , Vinyl chloride-based polymers, nylon or aromatic polyamides and other amide-based polymers, imine-based polymers, turpentine-based polymers, polyether turpentine-based polymers, polyether ether ketone-based polymers, and Benzene sulfide polymer, vinyl alcohol polymer, chlorinated vinylene polymer, vinyl butyral polymer, aryl ester polymer, polyoxymethylene polymer, epoxy polymer or the above-mentioned polymers The blends and so on.

The protective film may contain one or more arbitrary and appropriate additives. Examples of additives include ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

The content of the above-mentioned polymer in the protective film is preferably 50-100% by weight, preferably 50-99% by weight, more preferably 60-98% by weight, and even more preferably 70-97% by weight. When the content of the polymer in the protective film is less than 50% by weight, there is a possibility that the high transparency originally possessed by the polymer may not be sufficiently exhibited.

The aforementioned protective film can also use a retardation film, a brightness enhancement film, a diffusion film, and the like. Examples of the retardation film include those having a frontal retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more. The frontal phase difference is usually controlled in the range of 40~200nm, and the thickness direction phase difference is usually controlled in the range of 80~300nm. When a retardation film is used as a protective film, the retardation film can also function as a protective film of a polarizer, so it can be reduced in thickness.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The above-mentioned stretching temperature, stretching ratio, etc. can be appropriately set according to the retardation value, film material and thickness.

The thickness of the protective film can be appropriately determined, but it is about 1 to 500 μm from the viewpoint of workability such as strength and handleability, and thin layer properties. The thickness of the protective film is preferably 1 to 300 μm, preferably 5 to 200 μm, and more preferably 5 to 150 μm, and even more preferably 20 to 100 μm.

Functional layers such as hard coating, anti-reflection layer, anti-adhesion layer, diffusion layer and even anti-glare layer can be provided on the surface of the aforementioned protective film that is not adhered to the polarizer. In addition, functional layers such as the above-mentioned hard coat layer, anti-reflection layer, anti-adhesion layer, diffusion layer, or anti-glare layer may be provided in addition to the protective film itself, or may be separately provided as an individual from the protective film.

(3) Adhesive layer The adhesive layer is formed of an adhesive. The type of the adhesive is not particularly limited, and various substances can be used. The aforementioned adhesive layer is not particularly limited as long as it is optically transparent. The adhesive can be in various forms such as water-based, solvent-based, hot-melt adhesive, and active energy ray hardening type, but water-based adhesive or active energy ray hardening type Adhesive is suitable.

Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content.

The active energy ray hardening adhesive is an adhesive that is hardened with active energy rays such as electron beams and ultraviolet rays (radical hardening type, cation hardening type). For example, it can be used in the form of electron beam hardening type and ultraviolet hardening type. As the active energy ray-curable adhesive, for example, a light radical-curable adhesive can be used. When the photoradical curing type active energy ray curing type adhesive is used as an ultraviolet curing type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

The coating method of the adhesive can be appropriately selected according to the viscosity or the target thickness of the adhesive. Examples of coating methods include: reverse coater, gravure coater (direct, reverse or offset), bar type reverse coater, roll coater, die coater, bar coater, bar coater, etc. In addition, for coating, a dipping method or the like can be appropriately used.

In addition, when a water-based adhesive or the like is used for the application of the aforementioned adhesive, it is preferable to perform it so that the thickness of the finally formed adhesive layer becomes 30 to 300 nm. The thickness of the aforementioned adhesive layer is more preferably 60~250nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferable to perform it so that the thickness of the adhesive layer becomes 0.1 to 200 μm. It is more preferably 0.5~50μm, more preferably 0.5~10μm.

In addition, when a polarizer and a protective film are laminated, an easy-to-bond layer can be provided between the protective film and the adhesive layer. The easy-adhesive layer can be formed of various resins having, for example, the following skeletons: polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, polysiloxane system, polyamide skeleton, polyimide skeleton , Polyvinyl alcohol skeleton, etc. These polymer resins can be used individually by 1 type or in combination of 2 or more types. In addition, other additives may be added when forming the easy-to-adhesive layer. Specifically, stabilizers such as thickeners, ultraviolet absorbers, antioxidants, and heat-resistant stabilizers can be used.

The easy-to-bond layer is usually set on the protective film in advance, and the easy-to-bond layer side of the protective film and the polarizer are laminated by an adhesive layer. The formation of the easy-adhesive layer can be carried out by coating the forming material of the easy-adhesive layer on the protective film and drying it by a known technique. The easy-adhesive layer forming material is usually adjusted in consideration of the thickness after drying, the smoothness of the coating, etc., to prepare a solution that has been diluted to an appropriate concentration. The thickness of the easy bonding layer after drying is preferably 0.01~5μm, more preferably 0.02~2μm, and more preferably 0.05~1μm. Furthermore, the easy-adhesive layer may be provided with multiple layers, and in this case, it is also preferable that the total thickness of the easy-adhesive layer falls within the above range.

(4) Abnormity part The special-shaped part is a notch or a through hole.

The aforementioned notch is provided on the outer edge of the polarizing film. Specifically, as shown in FIG. 1, the aforementioned notch 2 is provided in at least one of the long side L, the short side W, and the outer corner 3 of the polarizing film 1 (in FIG. 1, the notch 2 is located on the long side, respectively). L, short side W, and outer edge corner 3 are each provided with 1). When a plurality of the aforementioned notches 2 are to be provided, they may have the same shape or different shapes. Two or more notches 2 may be provided on one long side L, or more than one on each of the two long sides L. In addition, two or more notches 2 may be provided on one short side W, or one or more notches may be provided on each of two short sides W. In addition, the aforementioned notch portion 2 may be provided at one of the four outer edge corners 3, or may be provided at two or more places. In addition, the outer edge corners 3 where the aforementioned notch 2 is not provided may be square corners or rounded corners.

The aforementioned notch 2 is composed of a straight line, a curved line, or a combination of these.

In the present invention, as shown in FIG. 1, the angle θ ₁ formed by the two straight lines constituting the shape of the notch portion 2 is 90° or more and less than 180°, and preferably 90° or more and 135° or less. When the angle θ ₁ is outside the aforementioned range (for example, when the notch is triangular), the stress due to expansion and contraction will be concentrated on the part 4 where the two straight lines intersect under the severe environment of thermal shock, making this part 4 easy Create cracks.

Furthermore, in the present invention, when the notch portion 2 is located on the long side L as shown in FIG. 2, the curvature radius R ₁ (mm) of the curve constituting the shape of the notch portion 2 satisfies the following formula (1) . When the notch 2 is located on the short side W, the curvature radius R ₁ (mm) of the curve constituting the shape of the notch 2 satisfies the following formula (2). Further, in the notch 3 is located in the outer edge of the corner portion 2, constituting the radius of curvature R 2 of the curved shape of the notch portion ₁ is 0.2mm or more, and should be of 2mm or more, and more preferably 2.5mm or more. R ₁ ＜(L ₁ -1)/2 (1) L ₁ ... The length of the notch on the long side L (mm) R ₁ ＜(W ₁ -1)/2 (2) W ₁ ... Length of notch on short side W (mm)

When the notch 2 is located on the long side L and the radius of curvature R ₁ does not satisfy the above formula (1), under the severe environment of thermal shock, the stress due to expansion and contraction will concentrate on the curve part, making the curve Some parts are prone to cracks.

In addition, when the notch 2 is located on the short side W and the radius of curvature R ₁ does not satisfy the above formula (2), under a severe environment of thermal shock, the stress due to expansion and contraction will concentrate on the curved part, causing The curve part is prone to cracks.

In addition, when the notch 2 is located at the outer corner 3 and the radius of curvature R _{1 is} less than 0.2 mm, under the severe environment of thermal shock, the stress due to expansion and contraction will concentrate on the curved part, making the curved part Prone to cracks.

_{The aforementioned L 1 of the} aforementioned notch 2 is preferably 100 to 200 mm, preferably 110 to 190 mm, and more preferably 110 to 180 mm. When the aforementioned L ₁ is outside the aforementioned range, cracks are likely to occur.

_{The aforementioned W 1 of the} aforementioned notch 2 is preferably 50-100 mm, preferably 50-90 mm, and more preferably 50-80 mm. When the aforementioned W ₁ is outside the aforementioned range, cracks are likely to occur.

_{The maximum depth D 1 of the} aforementioned notch 2 from the long side L is preferably 2-50mm, and more preferably 2-25mm, and even more preferably 5-10mm. When the maximum depth D ₁ is outside the aforementioned range, cracks are likely to occur.

_{The maximum depth D 2 of the} aforementioned notch 2 from the short side W is preferably 2~25mm, more preferably 2~13mm, and more preferably 5~10mm. When the maximum depth D ₂ is outside the aforementioned range, cracks are likely to occur.

FIG. 3 is a schematic diagram showing another specific example of the shape of the notch 2. In addition, as long as the notch portion 2 is composed of a straight line, a curve, or a combination thereof as described above, and the angle θ ₁ is 90° or more and less than 180°, and the curvature radius R ₁ satisfies the above formulas (1) and (2) or curvature A shape with a radius R ₁ of 0.2 mm or more is sufficient, and other shapes are not particularly limited, and can be made into any shape according to the purpose, function, and design of the polarizing film.

The aforementioned through holes are arranged inside the plane of the polarizing film. Specifically, as shown in FIG. 4, at least one through hole 5 is provided inside the plane of the polarizing film 1 (in FIG. 4, two through holes 5 are provided). When a plurality of through holes 5 are to be provided, they may be of the same shape or different shapes.

The aforementioned through hole 5 is composed of a straight line, a curved line, or a combination of these.

In the present invention, as shown in FIG. 4, the angle θ ₂ formed by the two straight lines constituting the shape of the through hole 5 is 90° or more and less than 180°, and preferably 90° or more and 135° or less. When the angle θ ₂ is outside the aforementioned range (for example, when the through hole is triangular), under severe thermal shock environment, the stress due to expansion and contraction will be concentrated on the part 6 where the two straight lines intersect, making this part 6 easy Create cracks.

Furthermore, in the present invention, as shown in FIG. 4, the radius of curvature R ₂ of the curve constituting the shape of the aforementioned through hole 5 is 0.6 mm or more, preferably 1 mm or more, and preferably 2 mm or more, more preferably 3 mm or more, and more It is preferably 5mm or more; it is also preferably 30mm or less, and preferably 25mm or less, more preferably 20mm or less, and more preferably 10mm or less. When the radius of curvature R _{2 is} less than 0.6 mm, under the severe environment of thermal shock, the stress based on expansion and contraction will be concentrated on the curve part, making the curve part prone to cracks.

As long as the through hole 5 is formed by a straight line, a curve, or a combination of the above, and the angle θ ₂ is 90° or more and less than 180°, or the curvature radius R ₂ is 0.6 mm or more, other shapes are not special. Restricted, any shape can be adopted according to the purpose, function and design of the polarizing film.

Examples of the shape of the through hole 5 include a circle, an ellipse (one symmetry axis and two symmetry axes), a rectangle with rounded corners, a square (square, rectangle), and a polygon with five or more corners. When it is round, the radius should be 0.6~30mm, and should be 2~10mm. When it is elliptical, the long diameter should be larger than the following short diameter value and the shorter side W should be smaller, and the short diameter should be 0.6~30mm, and more preferably 2~10mm. When it is a rectangle with rounded corners, the radius of curvature of the rounded corners should be 0.6~30mm, and 2~10mm is better, and the length of the long axis should be 10~200mm, and 50~190mm is better, and 110~190mm is better. When it is square, the side length should be 10~200mm, and should be 50~100mm. When it is a rectangle, the long side should be 10~200mm, and should be 50~190mm, more preferably 110~190mm, and the short side should be 5~100mm, and should be 25~90mm, more preferably 50~90mm.

The polarizing film of the present invention may have one or more notches 2 and one through hole 5 each.

Examples of methods for forming the aforementioned deformed portion include punching processing, end mill processing, and laser processing. The aforementioned deformed portion is generally formed by the aforementioned processing after laminating each layer.

2. Polarizing film with adhesive layer The polarizing film with an adhesive layer of the present invention has the aforementioned polarizing film and an adhesive layer.

When a double-sided protective polarizing film is provided with a protective film on both sides of the polarizer, an adhesive layer is provided on one side of the double-sided protective polarizing film directly or through other layers. In addition, a surface protective film can also be provided on the other side of the double-sided protective polarizing film directly or through other layers.

When a single-sided protective polarizing film is provided with a protective film on only one side of the polarizer, an adhesive layer is provided on the polarizer side of the single-sided protective polarizing film directly or through other layers. In addition, a surface protective film may be provided on the side of the protective film of the single-sided protective polarizing film directly or via another layer.

The aforementioned other layer is not particularly limited, and it may be a well-known functional layer or optical layer provided on a polarizing film. Examples of the optical layer include reflective plates, semi-transmissive plates, retardation plates (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, and brightness enhancement films. The aforementioned other layers may be provided with one layer or two or more layers.

The aforementioned adhesive layer is provided on one side of the polarizing film in order to bond the polarizing film to a unit substrate such as a liquid crystal cell.

The thickness of the aforementioned adhesive layer is not particularly limited. For example, it may be about 1-100 μm, preferably 2-50 μm, more preferably 2-40 μm, and even more preferably 5-35 μm.

An appropriate adhesive can be used for the formation of the aforementioned adhesive layer, and there is no particular limitation on the type thereof. Examples of adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, and polyvinyl pyrrole. Pyridone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc.

Among these adhesives, it is also suitable to use those having good optical transparency, exhibiting moderate wettability, adhesion characteristics of aggregation and adhesion, and excellent weather resistance and heat resistance. For those who exhibit such characteristics, it is better to use an acrylic adhesive.

The method of forming the adhesive layer can be, for example, the method of applying the aforementioned adhesive to the separated parts that have been peeled off, and then drying and removing the polymerization solvent to form an adhesive layer, and then transferring it to a polarizing film ; Or coating the aforementioned adhesive and drying and removing the polymerization solvent to form an adhesive layer on the polarizing film. In addition, one or more solvents other than the polymerization solvent may be added appropriately when applying the adhesive.

Polysilicon release liner material should be used for the separated parts that have been stripped. In the step of coating the adhesive on the lining material and drying it to form an adhesive layer, the method of drying the adhesive may adopt an appropriate and appropriate method depending on the purpose. It is suitable to use a method of overheating and drying the above-mentioned coated film. The heating and drying temperature should be 40℃~200℃, more preferably 50℃~180℃, especially 70℃~170℃. By setting the heating temperature within the above range, an adhesive with excellent adhesive properties can be obtained.

The drying time can be appropriately used. The above drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Various methods can be used to form the adhesive layer. Specifically, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brush, spray cloth, dip roll coating, bar coating, knife coating, pneumatic knife coating , Curtain coating, lip coating, extrusion coating using die coaters, etc.

When the aforementioned adhesive layer is exposed, the peel-off treated sheet (separator) can be used to protect the adhesive layer until it is used for practical use.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; porous materials such as paper, cloth, and non-woven fabrics; meshes and foamed sheets. Appropriate sheets such as, metal foil, and laminates thereof, etc., but in terms of excellent surface smoothness, plastic films are suitable.

The plastic film is not particularly limited as long as it can protect the aforementioned adhesive layer. Examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, and polyvinyl chloride. Film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-ethyl acetate copolymer film, etc.

The thickness of the aforementioned separator is usually 5 to 200 μm, preferably about 5 to 100 μm. The aforementioned separating parts can also be demoulded and antifouling treated with silicone, fluorine, long-chain alkyl or fatty acid amide-based mold release agents, silica powder, etc., as well as coating type, Antistatic treatment such as kneading type and vapor deposition type. In particular, by appropriately performing peeling treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the separator, the peelability from the adhesive layer can be further improved.

The aforementioned surface protection film usually has a substrate film and an adhesive layer, and the polarizing film is protected via the adhesive layer.

From the viewpoints of inspection and management, the base film of the aforementioned surface protection film can be selected from isotropic or nearly isotropic film materials. The film material may include, for example, polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyether turpentine resins, polycarbonate resins, polyamide resins, etc. Transparent polymers like polyimide resins, polyolefin resins, and acrylic resins. Among them, polyester-based resins are suitable. The substrate film can be used in the form of a laminate of one or more than two film materials, or an extension of the aforementioned film can be used. The thickness of the substrate film is usually 500 μm or less, preferably 10 to 200 μm.

The adhesive that forms the adhesive layer of the aforementioned surface protection film can be appropriately selected from (meth)acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, and fluorine-based polymers. Or rubber-based polymers are used as adhesives for base polymers. From the viewpoints of transparency, weather resistance, heat resistance, etc., an acrylic adhesive using an acrylic polymer as the base polymer is suitable. The thickness of the adhesive layer (dry film thickness) can be determined according to the required adhesive force. Usually it is about 1-100μm, preferably 5-50μm.

In addition, the surface protection film can also be provided with a release treatment layer on the opposite side of the base film where the adhesive layer is provided by low-adhesive materials such as silicone treatment, long-chain alkyl treatment, fluorine treatment, etc.

3. Image display device The image display device of the present invention only needs to include the polarizing film of the present invention or the polarizing film with an adhesive layer, and the rest of the structure can be the same as the conventional image display device. The aforementioned polarizing film or polarizing film with an adhesive layer can be applied to an image display unit. For example, when the image display device is a liquid crystal display device, the aforementioned polarizing film or polarizing film with an adhesive layer can be applied to either the viewing side or the backlight side of the image display unit (liquid crystal unit). When the image display device is an organic EL display device, the aforementioned polarizing film or the polarizing film with an adhesive layer can be applied to the viewing side of the image display unit. Since the image display device of the present invention includes the aforementioned polarizing film or the polarizing film with an adhesive layer, it has a high degree of reliability. Example

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. As for the parts and% in each case, they are all based on weight.

(Making polarized parts) Apply corona treatment to one side of the substrate of amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100μm) with a water absorption rate of 0.75% and a Tg of 75°C, and the corona The treated surface was coated at 25°C and contained polyvinyl alcohol (polymerization degree: 4200, saponification degree: 99.2 mol%) and acetyl acetyl modified PVA (polymerization degree: 1200, acetyl acetate in a ratio of 9:1). Modification degree of the base: 4.6%, degree of saponification: 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") in an aqueous solution and dried to form a PVA-based resin layer with a thickness of 11 μm. Out of the layered body. In an oven at 120°C, the obtained laminate was uniaxially stretched 2.0 times at the free end in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds (air-assisted stretch processing). Next, the layered body was immersed in an insoluble bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30°C for 30 seconds (insoluble treatment). Next, it was immersed in a dyeing bath with a liquid temperature of 30°C while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, it was immersed in an iodine aqueous solution obtained by mixing 0.2 parts by weight of iodine and 1.0 part by weight of potassium iodide with respect to 100 parts by weight of water for 60 seconds (dyeing treatment). Next, it was immersed in a cross-linking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water with a liquid temperature of 30°C) for 30 seconds (cross-linking treatment) . Then, while immersing the layered body in an aqueous solution of boric acid (an aqueous solution obtained by mixing 4.5 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70°C, rolls with different peripheral speeds Uniaxial stretching is carried out in the longitudinal direction (long side direction) so that the total stretching magnification reaches 5.5 times (underwater stretching treatment). Thereafter, the layered body was immersed in a washing bath (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30°C (washing treatment). In the above manner, an optical thin film laminate including a polarizer with a thickness of 5 μm was produced. The boric acid content of the prepared polarizer was 20% by weight.

(Making adhesives for protective films) Blending 40 parts by weight of N-Hydroxyethyl acrylamide (HEAA), 60 parts by weight of ACMO, and 3 parts by weight of photoinitiator "IRGACURE 819" (manufactured by BASF Corporation) to prepare ultraviolet rays Hardening adhesive.

(Making protective film) In a 30L tank reactor equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube, 8,000 g of methyl methacrylate (MMA) and 2,000 g of 2-(hydroxymethyl) are fed Methyl acrylate (MHMA), 10,000g of 4-methyl-2-pentanone (methyl isobutyl ketone, MIBK), 5g of n-dodecanethiol, and while passing nitrogen through them, the temperature is raised to 105°C and After refluxing, 5.0 g of tertiary butyl peroxy isopropyl carbonate (Kayakarubon BIC-7, manufactured by KAYAKU AKZO CO., LTD.) was added as a polymerization initiator, and it took 4 hours to drop the tertiary butyl peroxy isopropyl carbonate (Kayakarubon BIC-7, manufactured by KAYAKU AKZO CO., LTD.). A solution composed of butylperoxyisopropyl carbonate and 230g of MIBK is subjected to solution polymerization at about 105~120°C under reflux, and then takes 4 hours to mature. 30g of octadecyl phosphate/di(octadecyl) phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) was added to the prepared polymer solution, and the mixture was refluxed at about 90~120 The cyclization condensation reaction was carried out at ℃ for 5 hours. Then, the prepared polymer solution was introduced into the sleeve at a processing speed of 2.0 kg/h converted from the amount of resin. The temperature was 260°C, the number of rotations was 100 rpm, the degree of decompression was 13.3~400hPa (10~300mmHg), and the number of rear vent holes One vent type twin-screw extruder with 4 front vent holes (φ=29.75mm, L/D=30), and in the extruder, the cyclization condensation reaction and devolatization are further carried out. Extrusion is performed to obtain transparent pellets of a polymer containing lactone rings. After performing dynamic TG measurement on the prepared lactone ring-containing polymer, a mass loss of 0.17% by mass was detected. In addition, the weight average molecular weight of the lactone ring-containing polymer was 133,000, the melt flow rate was 6.5 g/10 min, and the glass transition temperature was 131°C. Using a uniaxial extruder (screw 30mmφ), the pellets and acrylonitrile-styrene (AS) resin (TOYO AS AS20, manufactured by TOYO STYRENE CO., LTD.) were kneaded at a mass ratio of 90/10 Extrusion, thereby making transparent pellets. The glass transition temperature of the obtained pellets was 127°C. The pellets were melt-extruded from a 400mm wide hanger-type T-die using a 50mmφ uniaxial extruder to produce a film with a thickness of 80μm. In addition, it was melt-extruded while supplying 0.66 parts by weight of an ultraviolet absorber (manufactured by ADEKA, trade name: LA-F70) with respect to 100 parts by weight of the resin in the pellets. Using a biaxial stretching device, the produced film was stretched 2.0 times at a temperature of 150° C. to obtain a stretched film with a thickness of 20 μm. After measuring the optical properties of the stretched film, it was found that the total light transmittance was 93%, the in-plane retardation Δnd was 0.8 nm, and the thickness direction retardation Rth was 1.5 nm.

Example 1 (Preparation of a double-sided protective polarizing film with notches) The surface of the polarizer (thickness: 5μm) of the above-mentioned optical film laminate was coated so that the thickness of the cured adhesive layer became 0.1μm. UV-curing adhesive and the protective film prepared by the above method are simultaneously laminated, and then irradiated with ultraviolet rays as active energy rays to harden the adhesive. After that, the amorphous PET substrate provided on one side of the polarizer was peeled off, and a brightness enhancement film (manufactured by Sumitomo 3M Co., Ltd., APF-V3) was attached to the peeling surface with an adhesive. An adhesive layer (thickness: 20 μm) was formed on the aforementioned protective film to produce a double-sided protective polarizing film. After that, the double-sided protective polarizing film is cut to the size of L130mm on the long side and W65mm on the short side. Then, the long side of the double-sided protective polarizing film is processed by an end mill to form a notch as shown in Figure 2 (radius of curvature R ₁ : 2.5mm, length L ₁ : 12mm, maximum depth D ₁ : 7mm) , And produced a double-sided protective polarizing film with notches.

Examples 2~6, Comparative Examples 1~3 (Making a double-sided protective polarizing film with notches) The double-sided protective polarizing film with the size described in Table 1 was cut out, and the notched portion of the shape described in Table 1 was formed. Except that, the same method as in Example 1 was followed to produce a double-sided protective polarizing film with notched portion. In addition, the notch part of Example 6 is the shape shown in FIG. 1, and the notch part of Comparative Example 3 is a triangle.

Examples 7 to 13, Comparative Examples 4 to 7 (making double-sided protective polarizing films with circular through holes) According to the same method as in Example 1, double-sided protective polarizing films of the sizes described in Table 2 were prepared. Thereafter, the process by CO ₂ laser described in Table 2 of radius of curvature R ₂ of the circular through hole shown in FIG. 4 for protecting a polarizer film formed on a double-sided, double-sided produced having through holes of circular polarization Protection film.

Examples 14-16 (Making double-sided protective polarizing films with rectangular through holes) According to the same method as in Example 1, double-sided protective polarizing films of the sizes described in Table 3 were prepared. After that, the rectangular through hole shown in FIG. 4 was formed on the double-sided protective polarizing film with the size described in Table 3 _{by CO 2 laser processing to produce a double-sided protective polarizing film with rectangular through holes.}

Comparative Example 8 (Production of a double-sided protective polarizing film with equilateral triangle through holes) According to the same method as in Example 1, a double-sided protective polarizing film of the size described in Table 3 was prepared. Afterwards, by CO ₂ laser processing _{, an equilateral triangular through hole with an angle θ 2} of 60° and a side length of 5 mm was formed on the double-sided protective polarizing film to produce a double-sided protective polarizing film with equilateral through-holes.

The following evaluations were performed on the polarizing films produced in the examples and comparative examples. List the results in Tables 1~3.

>Thermal shock test of polarizing film> The double-sided protective polarizing films having notches or through holes produced in the examples and comparative examples were bonded to 0.5 mm thick alkali-free glass to produce samples. Apply 200 cycles or 50 cycles of thermal shock at -40°C (maintained for 30 minutes) to 85°C (maintained for 30 minutes) to the sample. After that, it was confirmed with an optical microscope whether there were cracks or penetrating cracks in the notches or through holes of the aforementioned polarizing film.

In the case of the aforementioned polarizing film with notches, after 200 cycles, when the crack size is less than 200μm, it is evaluated as ○, when the crack size is less than 200μm, it is evaluated as △, and when it is greater than 1000μm or when there are penetrating cracks, it is evaluated as x.

In the case of the aforementioned polarizing film with through holes, after 50 cycles, when the crack size is less than 200 μm, it is evaluated as ○, when the crack size is less than 200 μm, it is evaluated as △, and when the crack size is greater than 1000 μm or when penetrating cracks are generated, it is evaluated as ×.

[Table 1]

[Table 2]

[table 3]

It can be seen from Tables 1 to 3 that the polarizing films of Examples 1 to 16 are less likely to cause cracks in the notches or through holes due to thermal shock, and have excellent crack resistance. On the other hand, the polarizing films of Comparative Examples 1 to 8 immediately caused cracks in the notches or penetrations due to thermal shock.

Industrial availability The polarizing film of the present invention can be used alone or in the form of an optical film formed by laminating it in image display devices such as liquid crystal display devices (LCD) and organic EL display devices.

1‧‧‧Polarizing film 2‧‧‧Notch 3‧‧‧Outer edge corner 4,6‧‧‧The part where 2 straight lines intersect 5‧‧‧Through hole L‧‧‧Long side L _{1 ‧‧‧Notch} The length L ₂ on the long side L ‧‧‧The length of the through hole in the direction of the long side L W‧‧‧The short side W ₁ ‧‧‧The length of the notch on the short side W W ₂ ‧‧‧The length of the through hole on the short side W _{Width D 1 in the} direction of the _{short side W ‧‧‧Maximum depth D 2 of the} notch from the long side L ‧‧‧Maximum depth of the notch from the short side W θ ₁ , θ ₂ ‧‧‧Angle R formed by 2 straight lines _1. R ₂ ‧‧‧The radius of curvature of the curve

Fig. 1 is a schematic diagram showing a specific example of the shape of the notch portion of the present invention. Fig. 2 is a schematic diagram showing another specific example of the shape of the notch portion of the present invention. Fig. 3 is a schematic diagram showing another specific example of the shape of the notch portion of the present invention. Fig. 4 is a schematic diagram showing a specific example of the through hole shape of the present invention.

1‧‧‧Polarizing film

2‧‧‧Notch

3‧‧‧Outer edge corner

4‧‧‧The part where two straight lines intersect

L‧‧‧long side

L ₁ ‧‧‧The length of the notch on the long side L

W‧‧‧Short side

W ₁ ‧‧‧The length of the notch on the short side W

D ₁ ‧‧‧Maximum depth of notch from long side L

D ₂ ‧‧‧Maximum depth of notch from short side W

θ ₁ ‧‧‧The angle formed by 2 straight lines

Claims (10)

A polarizing film, a protective film is provided on one or both sides of a polarizer with an adhesive layer interposed therebetween. The polarizing film is characterized in that the long side L of the outer edge of the polarizing film is 60~400mm and the short side W is 30~ 300mm, and the length of the long side L is greater than the length of the short side W; the polarizing film has more than one shaped part, and the shaped part is selected from at least one of the notch part and the through hole; the notch part is provided in the aforementioned On the outer edge of the polarizing film, the shape of the notch is composed of a straight line or a combination of a straight line and a curve; the angle θ ₁ formed by the two straight lines constituting the shape of the notch is 90° or more and less than 180°, and the notch has When one or more angles are at an angle θ _{1 and} the notch is located on the long side L, the curvature radius R _{1 of the} curve forming the shape of the notch satisfies the following formula (1), and the notch is located on the short side W _{When the radius of curvature R 1 of the} curve constituting the shape of the notch part satisfies the following formula (2), and when the notch part is located at the corner of the outer edge, the radius of curvature R ₁ of the curve constituting the shape of the notch part is 0.2 mm or more; the through hole is provided inside the plane of the polarizing film, and the shape of the through hole is composed of a straight line or a combination of a straight line and a curve; the angle θ ₂ formed by the two straight lines forming the shape of the through hole is 90° Above and below 180°, and the radius of curvature R ₂ of the curve forming the shape of the through hole is 0.6 mm or more; R ₁ <(L ₁ -1)/2 (1) L ₁ ... the notch is on the long side The length on L (mm), R ₁ <(W ₁ -1)/2 (2) W ₁ ... The length of the notch on the short side W (mm). The polarizing film of claim 1, wherein the notch is provided in at least one of the long side L, the short side W, and the outer edge corner. The polarizing film of claim 1 or 2, wherein the L ₁ of the notch is 100 to 200 mm, and _{the length of the L 1} is less than the length of the long side L. The polarizing film of claim 1 or 2, wherein the W ₁ of the notch part is 50-100 mm, and _{the length of the W 1} is less than the length of the short side W. The polarizing film of claim 1 or 2, wherein the maximum depth D ₁ of the notch portion from the long side L is 2-50 mm, and the maximum depth D _{1 is} less than the length of the short side W. Such as the polarizing film of claim 1 or 2, wherein the maximum depth D ₂ of the notch portion from the short side W is 2-25 mm. The polarizing film of claim 1 or 2, wherein the aforementioned through hole is a rectangle with rounded corners, a quadrangular shape, or a polygonal shape with five or more corners. The polarizing film of claim 1 or 2, wherein the thickness of the aforementioned polarizing member is 10 μm or less. A polarizing film with adhesive layer, with the requirements The polarizing film and adhesive layer of any one of items 1 to 8. An image display device, in which the polarizing film of any one of claims 1 to 8 or the polarizing film with an adhesive layer as claimed in claim 9 is arranged in an image display unit.

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