TW202000819A - Polarization film, polarization film with adhesive layer, and image display device - Google Patents

Abstract

The objective of the present invention is to provide a polarization film having a nicked portion and/or a through-hole where cracks do not readily occur even under a severe thermal shock environment. In this polarization film, a protective film is provided via an adhesive layer on one or both surfaces of a polarizer. The outer edges of this polarization film comprise a long side L of 60 to 400 mm and a short side W of 30 to 300 mm. The polarization film has one or more deformed parts of at least one type selected from the nicked portion and the through-hole. The nicked portion is provided in the outer edge of the polarization film. The shape of the nicked portion comprises a straight line, a curved line, or a combination thereof. An angle [Theta]1 formed by two of the straight lines constituting the shape of the nicked portion is 90 DEG or greater but less than 180 DEG. A radius of curvature R1 of the curved line constituting the shape of the nicked portion is of a specific size. The through-hole is provided within the plane of the polarization film. The shape of the through-hole comprises a straight line, a curved line, or a combination thereof. An angle [Theta]2 formed by two of the straight lines constituting the shape of the through-hole is 90 DEG or greater but less than 180 DEG. A radius of curvature R2 of the curved line constituting the shape of the through-hole is 0.6 mm or greater.

Description

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

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

Background of the invention In various image display devices, polarizing films are used for displaying images. For example, in view of the image forming method of a liquid crystal display device (LCD), it is necessary to dispose 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 the external light on the metal electrode, a circular polarizing 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 when a polarizing member composed of a polyvinyl alcohol-based film and a dichroic material such as iodine passes through a polyvinyl alcohol-based adhesive or the like and has a protective film laminated on one or both sides.

Under the severe environment of thermal shock (for example, repeated thermal shock tests conducted at -40°C and 85°C), the polarizing film may be easily absorbed in the direction of the absorption axis due to changes in the shrinkage stress of the polarizer The problem of cracks (penetrating cracks) occurs.

Patent Document 1 proposes a polarizing plate with the purpose of providing a polarizing plate that is excellent in durability even under cold and hot shock environments. The polarizing plate is formed by disposing 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 a direction orthogonal to the absorption axis and the linear expansion coefficient of the transparent protective film disposed on at least one surface of the polarizing film in a direction orthogonal to the absorption axis of the polarizing plate is 1.3× 10 ^-4 /℃ or less.

Prior technical literature Patent Literature Patent Document 1: Japanese Patent Laid-Open No. 2011-203571

Summary of the invention Problems to be solved by invention In the past, the screen of a mobile terminal such as a smartphone is generally rectangular. However, in recent years, from the viewpoints of screen enlargement and designability, liquid crystal panels with a special shape have gradually become a trend. The special-shaped part of the liquid crystal panel can be provided with a home screen button and a camera lens, etc. It is expected that the demand for the special-shaped liquid crystal panel will increase in the future. In order to manufacture a liquid crystal panel with a profiled portion, a polarizing film with a profiled portion is required.

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

An object of the present invention is to provide a polarizing film having a notch and/or a through hole, and the notch and the through hole are not likely to be cracked even under a severe environment of thermal shock.

Furthermore, an object of the present invention is to provide an adhesive-attached polarizing film having the polarizing film and the adhesive layer, and an image display device including the polarizing film or the adhesive-attached polarizing film.

The method used to solve the problem After an active review by the present inventors, it was found that the above-mentioned problems can be solved by the following polarizing film, and the present invention was completed.

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

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

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

Moreover, the maximum depth D ₁ from the long side L of the notch is preferably 2-50 mm, and the maximum depth D ₂ from the short side W is preferably 2-25 mm.

In addition, the through-holes are preferably round, elliptical, rounded rectangular, quadrangular, or polygonal with more than five pentagons.

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

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

The present invention also relates to an image display device, wherein the image display unit is provided with the polarizing film or the polarizing film with an adhesive layer.

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

Forms for carrying out 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 an adhesive layer, and the long side L of the outer edge of the polarizing film is 60 to 400 mm and the short side W is 30 to 300 mm (in addition, the long side Side L>short side W). The length of the long side L and the short side W can be appropriately adjusted according to the application of the polarizing film. For example, the long side L may be 100 to 200 mm, and the short side W may be 50 to 100 mm. In addition, the polarizing film has one or more shaped portions, and the shaped portion is selected from at least one of a notch portion and a through hole.

Each component will be described below.

(1) Polarizer The polarizer can be any known one without any limitation, but from the viewpoint of thinning and suppressing the occurrence of cracks, it is preferable to use a polarizer with a thickness of 10 μm or less. The thickness of the polarizer is more preferably 8 μm or less, 7 μm or less, and 6 μm or less. On the other hand, the thickness of the polarizer is 2 μm or more, and more preferably 3 μm or more.

The polarizer is made of polyvinyl alcohol resin. Examples of polarizers include the adsorption of iodine or dichroic dyes by hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene-vinyl acetate copolymer-based partially saponified films. Monochromatic substances, polyolefin oriented films such as polyvinyl alcohol dehydration treatment or polyvinyl chloride dehydrochlorination treatment, etc. Among them, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is more suitable.

The polarizing member in which the 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 and dyeing it, and stretching it to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, etc., or it may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol-based film is immersed in water and washed with water 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, the polyvinyl alcohol-based film swells to prevent uneven dyeing and other unevenness. The extension can be performed after dyeing with iodine, or it can be extended while dyeing, or it can be dyed with iodine after extension. It can also be extended in an aqueous solution 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 occurrence 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 standpoint of extension stability and humidification reliability, the boric acid content is preferably 10% by weight or more, and more preferably 12% by weight or more relative to the total amount of polarizers.

The representative of thin polarizers can be mentioned as follows: Specification of Japanese Patent No. 4751486, Specification of Japanese Patent No. 4751481, Specification of Japanese Patent No. 4815544, Specification of Japanese Patent No. 5048120, Manual of International Publication No. 2014/077599, The thin polarizer described in the manual of International Publication No. 2014/077636, etc., or the thin polarizer produced by the manufacturing method described there.

In the manufacturing method including the step of extending in the state of a laminate and the dyeing step, from the viewpoint of extending at a high magnification and improving the polarizing performance, the thin polarizer is described in Japanese Patent No. 4751486, Japanese Patent No. 4751481 The specification described in the Japanese Patent No. 4815544 and the Japanese Patent No. 4815544 are preferably prepared by a method including a step of extending in an aqueous solution of boric acid, and are particularly as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544 Preferably, it is prepared by a method including a step of auxiliary air 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 extension in the state of a laminate and dyeing step. As long as this manufacturing method is used, even if the PVA-based resin layer is very thin, it is supported by the resin substrate for stretching, so that it can be stretched without being broken due to stretching.

(2) Protective film The material of the protective film should preferably be excellent in transparency, mechanical strength, thermal stability, moisture blocking property and isotropy. Examples include polyester-based polymers such as polyethylene terephthalate or polyethylene naphthalate; cellulose-based polymers such as diethyl cellulose or triethyl cellulose; polymethacrylate Acrylic polymers such as esters; styrene polymers such as polystyrene or acrylonitrile-styrene copolymers (AS resins); polycarbonate polymers and the like. In addition, the following polymers can be cited as examples of the polymer forming the above protective film: polyethylene, polypropylene, polyolefin having a ring system or a norbornene structure, such as an ethylene-propylene copolymer polyolefin polymer , Vinyl chloride polymer, nylon or aromatic polyamide amide polymer, amide imide polymer, lanyard polymer, polyether lanyard polymer, polyether ether ketone polymer, polyextrusion Phenylsulfide-based polymer, vinyl alcohol-based polymer, chlorinated vinylidene-based polymer, vinyl butyral-based polymer, aryl ester-based polymer, polyoxymethylene-based polymer, epoxy-based polymer or the above-mentioned polymer Of blends, etc.

The protective film may contain one or more arbitrary and appropriate additives. Additives include, for example, ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, colorants, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

The content of the polymer in the protective film is preferably 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and even more preferably 70 to 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 and the like inherent in the polymer may not be sufficiently exhibited.

As the protective film, a phase difference film, a brightness enhancement film, a diffusion film, etc. can also be used. Examples of the retardation film include those having a frontal phase difference of 40 nm or more and/or a thickness direction phase difference 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 that it can be made thinner.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching magnification, etc. can be appropriately set according to the phase difference 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 viewpoints of workability such as strength and operability, and thinness. The thickness of the protective film is preferably 1 to 300 μm, preferably 5 to 200 μm, more preferably 5 to 150 μm, and even more preferably 20 to 100 μm.

A functional layer such as a hard coat layer, an anti-reflection layer, an anti-adhesion layer, a diffusion layer, and even an anti-glare layer may be provided on the surface of the aforementioned protective film that does not follow the polarizer. In addition, the functional layer such as the hard coat layer, the anti-reflection layer, the anti-adhesion layer, the diffusion layer, or the anti-glare layer can be provided separately from the protective film in addition to the protective film itself.

(3) Adhesive layer The adhesive layer is formed of an adhesive. The type of adhesive is not particularly limited, and various substances can be used. The adhesive layer is not particularly limited as long as it is optically transparent. Adhesives can be used in various forms such as water-based, solvent-based, hot-melt adhesive, and active energy ray-curable types, except for water-based adhesives or active energy ray-curable types. Adhesive is appropriate.

Examples of the water-based adhesive 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-curable adhesive is an adhesive that is cured by active energy rays such as electron beams, ultraviolet rays (radical curing type, cation curing type), etc. For example, it can be used in the form of electron beam curing type or ultraviolet curing type. For the active energy ray hardening type adhesive, for example, a photo radical hardening type adhesive can be used. When the photoradical hardening type active energy ray hardening type adhesive is used as the ultraviolet hardening type, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

The application method of the adhesive can be appropriately selected according to the viscosity or the target thickness of the adhesive. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or lithography), a bar reverse coater, a roll coater, a die coater, a bar coater, and a rod coater. In addition, for coating, a method such as a dipping method can be used as appropriate.

In addition, when using an aqueous adhesive or the like for the application of the adhesive, the thickness of the adhesive layer to be finally formed is preferably 30 to 300 nm. The thickness of the aforementioned adhesive layer is more preferably 60 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferably performed so that the thickness of the adhesive layer is 0.1 to 200 μm. It is preferably 0.5-50 μm, and more preferably 0.5-10 μm.

In addition, when laminating the polarizer and the protective film, an easy adhesion layer may be provided between the protection film and the adhesive layer. The easy-adhesion layer may 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 alone or in combination of two or more. In addition, other additives may be added when the easy-adhesion layer is formed. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, heat-resistant stabilizers, and the like can be used.

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

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

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

The aforementioned notch 2 is composed of a straight line, a curve, 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 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), under the severe environment of thermal shock, the stress due to expansion and contraction will be concentrated on the part 4 where the two straight lines intersect, making this part 4 easy Cracked.

Furthermore, in the present invention, when the notch 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 2 satisfies the following formula (1) . In addition, when the notch 2 is located on the short side W, the radius of curvature R ₁ (mm) of the curve constituting the shape of the notch 2 satisfies the following formula (2). In addition, when the notch 2 is located at the outer corner 3, the curvature radius R ₁ of the curve forming the shape of the notch 2 is 0.2 mm or more, preferably 2 mm or more, and more preferably 2.5 mm or more. R ₁ ＜(L ₁ -1)/2 (1) L ₁ ... Length of the notch on the long side L (mm) R ₁ ＜(W ₁ -1)/2 (2) W ₁ ... Length of the notch on the 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 be concentrated on the curve part, making the curve 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 the severe environment of thermal shock, stress due to expansion and contraction will concentrate on the curved portion, so that Cracks are likely to occur in this curve.

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, so that the curved part Easy to produce cracks.

The aforementioned L _{1 of the} 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} notch 2 is preferably 50 to 100 mm, preferably 50 to 90 mm, and more preferably 50 to 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 2-50 mm, more preferably 2-25 mm, and even more preferably 5-10 mm. 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 to 25 mm, more preferably 2 to 13 mm, and more preferably 5 to 10 mm. 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 of these, and the angle θ ₁ is 90° or more and less than 180°, and the radius of curvature R ₁ satisfies the above formulas (1) and (2) or the curvature The 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 hole is provided in the plane of the polarizing film. Specifically, as shown in FIG. 4, at least one through hole 5 is provided in the plane of polarizing film 1 (in FIG. 4, two through holes 5 are provided). When a plurality of the aforementioned through holes 5 are to be provided, these may have the same shape or different shapes.

The aforementioned through hole 5 is composed of a straight line, a curve, 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 the severe environment of thermal shock, the stress due to expansion and contraction will concentrate on the part 6 where the two straight lines intersect, making this part 6 easy Cracked.

Furthermore, in the present invention, as shown in FIG. 4, the radius of curvature R ₂ of the curve constituting the shape of the 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 should be 5mm or more; 30mm or less, 25mm or less, 20mm or less, and 10mm or less. When the radius of curvature R _{2 is} less than 0.6 mm, under the severe environment of thermal shock, stress due to expansion and contraction will concentrate on the curved portion, making the curved portion prone to cracks.

The through-hole 5 may be formed by a straight line, a curve, or a combination thereof, as described above, and the angle θ ₂ is 90° or more and less than 180°, or the radius of curvature R ₂ is 0.6 mm or more, and other shapes are not special. Restrictions, can be used in any shape 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 with a symmetry axis, and two with a symmetry axis), a rounded rectangle, a quadrangle (square, rectangle), and a polygon with five or more corners. When it is circular, the radius should be 0.6~30mm, and should be 2~10mm. When it is a round shape, the long diameter should be greater than the following short diameter value and the shorter side W is smaller, and the short diameter should be 0.6~30mm, and more preferably 2~10mm. In the case of rounded rectangles, the radius of curvature of the rounded corners should be 0.6 to 30 mm, preferably 2 to 10 mm, and the length of the long axis should be 10 to 200 mm, preferably 50 to 190 mm, and more preferably 110 to 190 mm. When it is square, the side length should be 10~200mm, and should be 50~100mm. When it is rectangular, 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 of the notch 2 and the through hole 5 each.

Examples of the method for forming the above-mentioned irregular portion include punching, end milling, and laser processing. The aforementioned deformed portion is generally formed by laminating each layer by the aforementioned processing.

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

When a double-sided protective polarizing film is provided with protective films on both sides of the polarizer, an adhesive layer is provided directly on one side of the double-sided protective polarizing film 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.

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

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

The adhesive layer is provided on one side of the polarizing film for bonding the polarizing film to a unit substrate such as a liquid crystal cell.

The thickness of the 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.

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

Among these adhesives, those having good optical transparency, exhibiting moderate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are suitable for use. For those exhibiting such characteristics, it is better to use acrylic adhesives.

The method of forming the adhesive layer may be, for example, a method of applying the adhesive to a separator subjected to peeling treatment, drying and removing the polymerization solvent, etc. to form an adhesive layer, and then transferring it to the polarizing film Or the method of applying the above adhesive, drying and removing the polymerization solvent, etc. to form an adhesive layer on the polarizing film. In addition, when applying the adhesive, one or more solvents other than the polymerization solvent may be appropriately added.

The separated parts after stripping treatment should use polysilicone stripping lining material. In the step of applying an adhesive on the lining material and drying it to form an adhesive layer, the method of drying the adhesive may be an appropriate and appropriate method depending on the purpose. It is preferable to use a method in which the above coating film is overheated and dried. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

The appropriate drying time can be adopted as the drying time. 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. Specific examples include roll coating, contact roll coating, gravure coating, reverse coating, roll brush, spray cloth, dip roll coating, bar coating, knife coating, and air knife coating , Curtain coating, lip coating, extrusion coating method using die coater, etc.

When the adhesive layer is exposed, the peeled sheet (separator) can be used to protect the adhesive layer until it is ready for practical use.

Examples of constituent materials of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; porous materials such as paper, cloth, and non-woven fabric; meshes, and foamed sheets , Metal foil, and other appropriate laminates such as laminates, etc., but from the viewpoint of excellent surface smoothness, it is suitable to use plastic film.

The plastic film is not particularly limited as long as it can protect the adhesive layer, and 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 separator can also be subjected to mold release and antifouling treatment using polysilicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, silica powder, etc., as well as coating type, Antistatic treatment such as kneading type and evaporation type. In particular, by appropriately performing peeling treatments such as polysiloxane 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 surface protection film usually has a base film and an adhesive layer, and the polarizing film is protected by the adhesive layer.

From the viewpoints of inspection and management, the substrate film of the surface protective film can be selected to have isotropic or nearly isotropic film materials. Examples of the film material include polyester-based resins such as polyethylene terephthalate films, cellulose-based resins, acetate-based resins, polyether-based resins, polycarbonate-based resins, and polyamide-based resins. Polyimide-based resin, polyolefin-based resin, acrylic resin-like transparent polymer. Among them, polyester resins are suitable. The base film can be used as a laminate of one or more types of 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 for forming the adhesive layer of the surface protective film can be appropriately selected from (meth)acrylic polymer, polysiloxane polymer, polyester, polyurethane, polyamide, polyether, and fluorine Or polymers such as rubbers 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 a 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 may be provided with a peeling treatment layer on the opposite surface of the base film with the adhesive layer by a low-adhesion material such as polysiloxane treatment, long-chain alkyl treatment, or fluorine treatment.

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 configuration may be the same as the conventional image display device. The aforementioned polarizing film or the polarizing film with an adhesive layer can be applied to the image display unit. For example, when the image display device is a liquid crystal display device, the polarizing film or the 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 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 polarizing film or the polarizing film with an adhesive layer, it has high reliability. Examples

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 are based on weight.

(Make polarizer) Corona treatment is applied to one side of the substrate of amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) with a water absorption of 0.75% and Tg75°C. The treated surface was coated with polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and modified PVA (degree of polymerization: 1200, degree of ethyl acetate) at a ratio of 9:1 at 25°C. Acrylic modification degree: 4.6%, saponification degree: 99.0 mol% or more, manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") and dried to form a PVA resin layer with a thickness of 11 μm. Out of the laminate. In an oven at 120° C., the obtained laminate was uniaxially stretched by 2.0 times in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds in the longitudinal direction (longitudinal direction) (air assisted stretching treatment). Next, the laminate was immersed in an insoluble bath (a boric acid aqueous solution obtained by blending 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 at a liquid temperature of 30°C, and the iodine concentration and the immersion time were adjusted at the same time to make the polarizing plate a predetermined transmittance. In this example, it was immersed in an aqueous iodine solution obtained by mixing 0.2 parts by weight of iodine and 1.0 parts 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 crosslinking 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) at a liquid temperature of 30°C (crosslinking treatment) . Then, while immersing the laminate in a boric acid aqueous solution having a liquid temperature of 70° C. (an aqueous solution obtained by blending 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), the rollers differ in the peripheral speed. Uniaxial stretching is carried out in the longitudinal direction (longitudinal direction) so that the total stretching magnification is 5.5 times (underwater stretching treatment). Thereafter, the laminate was immersed in a washing bath (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-mentioned manner, an optical film laminate including a polarizer having a thickness of 5 μm was produced. The boric acid content of the prepared polarizer was 20% by weight.

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

(Making protective film) In a 30-liter kettle-type reactor equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube, feed 8,000 g of methyl methacrylate (MMA) and 2,000 g of 2-(hydroxymethyl) Methyl acrylate (MHMA), 10,000g of 4-methyl-2-pentanone (methyl isobutyl ketone, MIBK), 5g of n-dodecanethiol, and heated to 105°C while passing nitrogen through After refluxing, 5.0 g of tertiary butylperoxy isopropyl carbonate (Kayakarubon BIC-7, manufactured by KAYAKU AKZO CO., LTD.) was added as a polymerization initiator, and it took 4 hours to drop 30.0 of tertiary from 10.0 g A solution consisting of butyl peroxy isopropyl carbonate and 230 g of MIBK is subjected to solution polymerization at about 105 to 120° C. under reflux, and it takes another 4 hours to ripen. Add 30g of octadecyl phosphate/di(octadecyl) phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) to the prepared polymer solution, and under reflux at about 90~120 Cyclization condensation reaction was carried out at ℃ for 5 hours. Next, the prepared polymer solution was introduced into a sleeve temperature of 260°C, a rotation speed of 100 rpm, a decompression degree of 13.3 to 400 hPa (10 to 300 mmHg), and a number of rear vent holes at a processing speed converted to 2.0 kg/h in terms of the amount of resin One vented twin-screw extruder with four front vents (φ=29.75mm, L/D=30), and further cyclization condensation reaction and devolatization in the extruder Extrusion is performed to obtain transparent pellets of the lactone ring-containing polymer. After performing dynamic TG measurement on the prepared polymer containing lactone ring, 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 obtained pellets were kneaded with acrylonitrile-styrene (AS) resin (TOYO AS AS20, manufactured by TOYO STYRENE CO., LTD.) at a mass ratio of 90/10 Squeeze to obtain transparent pellets. The glass transition temperature of the resulting pellets was 127°C. The pellets were melt extruded from a 400 mm wide hanger-type T-die using a 50 mmφ uniaxial extruder to produce a film with a thickness of 80 μm. In addition, it was melt-extruded while supplying an ultraviolet absorbent (product name: LA-F70 manufactured by ADEKA Corporation) of 0.66 parts by weight 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, thereby obtaining a stretched film with a thickness of 20 μm. After measuring the optical properties of the stretched film, the total light transmittance was 93%, the in-plane phase difference Δnd was 0.8 nm, and the thickness direction phase difference Rth was 1.5 nm.

Example 1 (Preparation of a double-sided protective polarizing film with a notch) On the surface of the polarizer (thickness: 5 μm) of the optical film laminate, the above was applied so that the thickness of the adhesive layer after curing became 0.1 μm After the ultraviolet curing adhesive and the protective film produced by the above method are simultaneously attached, the adhesive is 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 the brightening film (made by Sumitomo 3M Company, APF-V3) was attached with an adhesive on the peeled surface. An adhesive layer (thickness: 20 μm) is formed on the protective film to produce a double-sided protective polarizing film. After that, the double-sided protective polarizing film is cut into the size of long side L130mm and short side W65mm. After that, a long edge of the double-sided protective polarizing film is processed by an end mill to form a notch as shown in FIG. 2 (curvature radius R ₁ : 2.5 mm, length L ₁ : 12 mm, maximum depth D ₁ : 7 mm) , And produced a double-sided protective polarizing film with a notch.

Examples 2 to 6, Comparative Examples 1 to 3 (Making double-sided protective polarizing film with notch) A double-sided protective polarizing film of the size described in Table 1 was cut out to form a notch in the shape described in Table 1, except that a double-sided protective polarizing film having a notch was produced in the same manner as in Example 1. In addition, the notch portion of Example 6 has the shape shown in FIG. 1, and the notch portion of Comparative Example 3 has a triangular shape.

Examples 7 to 13 and Comparative Examples 4 to 7 (manufacturing of double-sided protective polarizing films with circular through holes) Double-sided protective polarizing films of the sizes described in Table 2 were produced in the same manner as in Example 1. 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 to 16 (Fabrication of a double-sided protective polarizing film with rectangular through holes) A double-sided protective polarizing film of the size described in Table 3 was produced in the same manner as in Example 1. After that, a rectangular through hole as shown in FIG. 4 was formed in the double-sided protective polarizing film by the CO ₂ laser processing at the size described in Table 3 to produce a double-sided protective polarizing film having a rectangular through hole.

Comparative Example 8 (Fabrication of a double-sided protective polarizing film having regular triangular through holes) A double-sided protective polarizing film of the size described in Table 3 was produced in the same manner as in Example 1. After that, an equilateral triangle through hole with an angle θ ₂ of 60° and a side length of 5 mm was formed in the double-sided protective polarizing film by CO ₂ laser processing to produce a double-sided protective polarizing film with an equilateral triangular through hole.

The polarizing films produced in Examples and Comparative Examples were evaluated as follows. The results are listed in Tables 1-3.

>The thermal shock test of polarized film> The double-sided protective polarizing film having notches or through-holes produced in Examples and Comparative Examples was bonded to a 0.5 mm-thick alkali-free glass to prepare a sample. To this sample, a thermal shock of -40°C (maintained for 30 minutes) ⇔ 85°C (maintained for 30 minutes) at 200 or 50 cycles was applied. After that, confirm with an optical microscope whether there are cracks or penetrating cracks in the notch or through hole of the polarizing film.

If it is the aforementioned polarizing film having a notch, after 200 cycles, it is evaluated as ○ when the crack size is less than 200 μm, △ when it is 200 to 1000 μm, and is evaluated as × when it is greater than 1000 μm or when a penetrating crack is generated.

If the polarizing film has a through hole, after 50 cycles, it is evaluated as ○ when the crack size is less than 200 μm, △ when it is 200 to 1000 μm, and × when it is greater than 1000 μm or when there is a penetrating crack.

[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 cutouts or through holes due to thermal shock, and are excellent in crack resistance. On the other hand, the polarizing films of Comparative Examples 1 to 8 immediately cracked in the notch or penetration portion due to thermal shock.

Industrial availability The polarizing film of the present invention can be used alone or in the form of a laminated optical film for image display devices such as liquid crystal display devices (LCDs) and organic EL display devices.

1‧‧‧Polarized film 2‧‧‧Notch part 3‧‧‧Outer corner 4,6‧‧‧‧Intersection of 2 straight lines 5‧‧‧Through hole L‧‧‧Long side L ₁ ‧‧‧Notch part Length L ₂ on the long side L ‧‧‧The length of the through hole in the long side L direction W‧‧‧Short side W ₁ ‧‧‧The length of the notch on the short side W ₂ ‧‧‧The through hole is The width D _{1 in the} direction of the short side W is the maximum depth D _{2 of the} notch from the long side L ₂ The maximum depth of the notch is θ ₁ and θ ₂ from the short side W ₁ , R ₂ ‧‧‧ curve radius of curvature

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 view showing another specific example of the shape of the notch portion of the present invention. 4 is a schematic view showing a specific example of the shape of the through hole of the present invention.

1‧‧‧ Polarized film

2‧‧‧Notch

3‧‧‧Outer corner

4‧‧‧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 ‧‧‧The maximum depth of the notch from the long side L

D ₂ ‧‧‧The maximum depth of the notch from the short side W

θ ₁ The angle formed by 2 straight lines

Claims (10)

A polarizing film is provided with a protective film on one side or both sides of the polarizer through an adhesive layer. 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~ 300 mm, and the polarizing film has one or more shaped portions, and the shaped portion is selected from at least one of a notch portion and a through-hole; the notch portion is provided at the outer edge of the polarizing film, and the shape of the notch portion is formed by a straight line, A curve or a combination of these; 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 shape of the notch is formed when the notch is on the long side L The curvature radius R _{1 of the} curve satisfies the following formula (1), and when the notch is located on the short side W, the curvature radius R _{1 of the} curve constituting the shape of the notch satisfies the following formula (2), the notch When located at the corner of the outer edge, the curvature radius R ₁ of the curve constituting 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 formed by a straight line, a curve, or the The combination constitutes the like; 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 the radius of curvature R ₂ of the curve constituting the shape of the through hole is 0.6 mm or more; R ₁ ＜(L ₁ -1)/2 (1) L ₁ ... the length (mm) of the notch on the long side L, R ₁ ＜(W ₁ -1)/2 (2) W ₁ .. The length (mm) of the notch on the short side W. 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 corner. The polarizing film according to claim 1 or 2, wherein the aforementioned L ₁ of the aforementioned notch is 100-200 mm. The polarizing film according to any one of claims 1 to 3, wherein the aforementioned W ₁ of the notch is 50 to 100 mm. The polarizing film according to any one of claims 1 to 4, wherein the maximum depth D ₁ of the notch from the long side L is 2-50 mm. The polarizing film according to any one of claims 1 to 5, wherein the maximum depth D ₂ of the notch from the short side W is 2 to 25 mm. The polarizing film according to any one of claims 1 to 6, wherein the through holes are circular, elliptical, rectangular with rounded corners, quadrangular or polygonal with a pentagonal angle or more. The polarizing film according to any one of claims 1 to 7, wherein the thickness of the aforementioned polarizer is 10 μm or less. A polarizing film with an adhesive layer, comprising the polarizing film according to any one of claims 1 to 8 and an adhesive layer. An image display device, wherein the image display unit is provided with a polarizing film according to any one of claims 1 to 8 or a polarizing film with an adhesive layer according to claim 9.

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