KR102179611B1 - Laminated polarizing film, manufacturing method therefor, laminated optical film, and image display device - Google Patents

Abstract

The laminated polarizing film of the present invention is a laminated polarizing film in which a polarizing film and an optical film other than a polarizer are laminated via a low-elastic adhesive layer (a), wherein the polarizing film is an adhesive on at least one side of the polarizer A transparent protective film is laminated through the layer (b), and the low-elastic adhesive layer (a) is laminated on the transparent protective film, and the storage elastic modulus at 25°C of the low-elastic adhesive layer (a) This is 3.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa, and the thickness of the low elastic adhesive layer (a) is 0.1 to 5 µm. The laminated polarizing film of the present invention has good impact resistance and heat buckling property.

Description

A laminated polarizing film, its manufacturing method, a laminated optical film, and an image display device TECHNICAL FIELD [LAMINATED POLARIZING FILM, MANUFACTURING METHOD THEREFOR, LAMINATED OPTICAL FILM, AND IMAGE DISPLAY DEVICE]

The present invention relates to a laminated polarizing film obtained by laminating a polarizing film and an optical film other than a polarizer through a low elasticity adhesive layer, and a manufacturing method thereof. The said laminated film can form image display devices, such as a liquid crystal display device (LCD), an organic EL display device, CRT, and PDP, as this alone or as a laminated optical film in which an optical film is laminated.

In a liquid crystal display device or the like, it is indispensable to arrange polarizing elements on both sides of a liquid crystal cell from the image forming method, and generally, a polarizing film is adhered. Moreover, in addition to a polarizing film, various optical films are used for a liquid crystal panel in order to improve the display quality of a display. For example, as the optical film, a retardation film for preventing coloring, a viewing angle enlargement film for improving the viewing angle of a liquid crystal display, and further, a luminance enhancing film for increasing the contrast of the display are used.

When the said polarizing film and an optical film (for example, a retardation film) are combined and used as a laminated polarizing film, the said polarizing film and an optical film were usually laminated via an adhesive layer (for example, Patent Document 1 ). In Patent Document 1, it is proposed that the pressure-sensitive adhesive layer has a storage elastic modulus at 23°C of 0.3 MPa or more from the viewpoint of preventing light leakage. In addition, in Patent Document 1, in order to satisfy the peeling force of the pressure-sensitive adhesive layer, an adhesive layer having a thickness of 5 to 100 µm is used.

Japanese Patent Application Publication No. 2008-032852

In the retardation film used for the laminated polarizing film, since molecules are surface-oriented in the film, they are easily cleaved by impact such as dropping. Therefore, for example, the impact resistance of the laminated product of a polarizing film and a retardation film was not sufficient.

Moreover, the said laminated polarizing film is provided for a heating test, a freezing cycle test (heat shock cycle test), etc. in the state of a panel bonded to a liquid crystal cell. However, in the pressure-sensitive adhesive layer described in Patent Document 1, it is difficult for the pressure-sensitive adhesive layer to follow the dimensional change of the polarizing film generated by the test, and when the laminated polarizing film after the test is observed in a cross-Nichol state, display defects such as uneven streaks are observed. I could see. Therefore, the laminated optical film is required that the laminated polarizing film is not subjected to streak variation or the like in a cross-Nichol state even after the above test (hereinafter, referred to as heat buckling property).

An object of the present invention is to provide a laminated polarizing film obtained by laminating a polarizing film and an optical film other than a polarizing film, and a laminated polarizing film having good impact resistance and heat buckling property, and a method for producing the same.

It is another object of the present invention to provide a laminated optical film using the laminated polarizing film, and furthermore, an image display device using the laminated polarizing film or laminated optical film.

In order to solve the above problem, the inventors of the present invention have found that the above problem can be solved using the following polarizing film or the like, and have come to complete the present invention.

That is, the present invention is a laminated polarizing film in which a polarizing film and an optical film other than a polarizer are laminated via an adhesive layer (a),

In the polarizing film, a transparent protective film is laminated on at least one surface of the polarizer through an adhesive layer (b), and the low-elastic adhesive layer (a) is laminated on the transparent protective film,

The storage elastic modulus at 25°C of the low elastic adhesive layer (a) is 3.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa,

Further, it relates to a laminated polarizing film characterized in that the thickness of the low-elastic adhesive layer (a) is 0.1 to 5 µm.

In the laminated optical film, a retardation film can be used as the optical film.

In the laminated optical film, it is preferable that the low-elastic adhesive layer (a) is a cured product layer obtained by irradiating an active energy ray-curable adhesive with an active energy ray.

In the laminated optical film, it is preferable that the active energy ray-curable adhesive is substantially free of an organic solvent and is a liquid product having a viscosity of 1 to 100 cp/25°C.

In the laminated optical film, it is preferable that the active energy ray-curable adhesive contains a radical polymerizable compound as a curable component.

In the laminated optical film, it is preferable that the radical polymerizable compound contains a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound (A). Moreover, when the total amount of the radical polymerizable compound is 100% by weight, it is preferable that the ratio of the polyfunctional radically polymerizable compound (A) is 1 to 65% by weight. Moreover, it is preferable that the said polyfunctional radical polymerizable compound (A) is a bifunctional (meth)acrylate having a weight average molecular weight of 200 to 4000.

In the laminated optical film, it is preferable that the radical polymerizable compound contains an alkyl (meth)acrylate (B) having an alkyl group having 2 to 18 carbon atoms.

In the laminated optical film, it is preferable that the radical polymerizable compound contains a (meth)acrylate (C) having a hydroxyl group. It is preferable that the (meth)acrylate (C) having a hydroxyl group is a hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000.

In the laminated optical film, it is preferable that the active energy ray-curable adhesive contains a silane coupling agent (D). It is preferable that the said silane coupling agent (D) is a silane coupling agent which does not have a radical polymerizable functional group.

In the laminated optical film, it is preferable that the active energy ray-curable adhesive contains an acrylic oligomer (E) obtained by polymerizing a (meth)acrylic monomer.

In the laminated optical film, it is preferable that the active energy ray-curable adhesive contains a radically polymerizable compound (F) having an active methylene group and a radical polymerization initiator (G) having a hydrogen extraction function. It is preferable that the active methylene group is an acetoacetyl group. It is preferable that the radical polymerizable compound (F) having an active methylene group is acetoacetoxyalkyl (meth)acrylate.

In the laminated optical film, it is preferable that the radical polymerization initiator (G) is a thioxanthone radical polymerization initiator.

In the laminated optical film, the adhesive layer (b) has a storage elastic modulus at 85° C. of 1.0×10 ⁶ to 1.0×10 ¹⁰ Pa and a thickness of 0.03 to 3 μm. You can use

Moreover, in the said laminated optical film, when the said transparent protective film is formed on both surfaces of said polarizer through said adhesive layer (b), as said adhesive layer (b), all An adhesive layer (b1) having a storage elastic modulus at 85°C of 1.0×10 ⁶ to 1.0×10 ¹⁰ Pa and a thickness of 0.03 to 3 μm can be used.

Further, in the laminated optical film, when the transparent protective film is formed on both surfaces of the polarizer through the adhesive layer (b), the adhesive layer (b) on one side is , Using an adhesive layer (b1) satisfying a storage modulus of 1.0 × 10 ⁶ to 1.0 × 10 ¹⁰ Pa at 85°C and a thickness of 0.03 to 3 μm, and the adhesive layer (b) on the other side The adhesive layer (b2) satisfies the storage modulus at 85°C of 1.0×10 ⁴ to 1.0×10 ⁸ Pa and a thickness of 0.1 to 25 μm can be used.

In the said laminated optical film, it is preferable that the said polarizer has a thickness of 1-10 micrometers.

In the laminated optical film, as the transparent protective film, a retardation film may be used as a transparent protective film on at least one side.

In the laminated optical film, when the polarizing film and the optical film are forcibly peeled, it is preferable that the low-elastic adhesive layer (a) is cohesively destroyed.

The laminated optical film preferably has a peeling force of 1 to 5 N/15 mm when the polarizing film and the optical film are forcibly peeled off.

In addition, the present invention is a method for producing the laminated polarizing film,

An active energy ray-curable adhesive for forming the low-elastic adhesive layer (a) on at least one surface of the transparent protective film on the side of the polarizing film on which the low-elastic adhesive layer (a) is laminated and the optical film With the coating process to apply,

A bonding step of bonding the polarizing film and the optical film, and

A laminated polarizing film comprising a bonding step of adhering the polarizing film and the optical film through the low elastic adhesive layer (a) obtained by irradiating the active energy ray to cure the active energy ray-curable adhesive. It relates to a method of manufacturing.

In the manufacturing method of the laminated polarizing film, the active energy ray preferably has a ratio of the integrated illuminance in the wavelength range of 380 to 440 nm and the integrated illuminance in the wavelength range of 250 to 370 nm in a range of 100:0 to 100:50.

Further, the present invention relates to a laminated optical film, wherein at least one laminated polarizing film is laminated.

Further, the present invention relates to an image display device in which the laminated polarizing film or the laminated optical film is used.

In the laminated polarizing film of the present invention, a polarizing film and an optical film other than a polarizer are laminated by a low-elastic adhesive layer (a). The adhesive layer is for the purpose of laminating and fixing the films, and is different from the adhesive layer formed on the premise that re-peelability is possible after laminating the films. The low-elastic adhesive layer (a) is firmly bonding a polarizing film and an optical film. Such a low-elastic adhesive layer (a) can maintain the peeling force between films at a predetermined or higher level even in the thickness of a thin layer (0.1 to 5 µm), and can also satisfy heat buckling property. In addition, the peeling force cannot be satisfied in the pressure-sensitive adhesive layer of a thin layer (0.1 to 5 µm). The thickness of the pressure-sensitive adhesive layer is increased to obtain a predetermined peeling force, but when the thickness of the pressure-sensitive adhesive layer is increased, it becomes difficult for the pressure-sensitive adhesive layer to follow the dimensional change of the polarizing film due to a heating test or a freezing cycle test, resulting in heat buckling properties. Can't be satisfied

In addition, since the low elasticity adhesive layer (a) of the present invention controls the storage elastic modulus at 25°C to 3.0×10 ⁵ to 1.0×10 ⁸ Pa, despite the low elasticity adhesive layer (a) being a thin layer, The laminated polarizing film has good impact resistance.

In addition, the laminated polarizing film of the present invention is particularly effective in terms of heat buckling properties and impact resistance in the case of a thin polarizer having a polarizer constituting the polarizing film having a thickness of 1 to 10 µm. Since the dimensional change of the thin polarizer is small, the dimensional change of the transparent protective film or the optical film other than the polarizer is relatively large, and heat buckling property tends to be inferior to the polarizer having a thickness of 10 μm or more. Moreover, since a thin polarizer has a higher elastic modulus than a polarizer having a thickness of 10 µm or more, the impact absorption property tends to be inferior to that of a polarizer having a thickness of 10 µm or more. According to the laminated polarizing film of the present invention, since it has a low-elastic adhesive layer (a), even when a thin polarizer is used, heat buckling resistance impact resistance can be satisfied.

1A is a cross-sectional view showing an embodiment of a laminated polarizing film of the present invention.
1B is a cross-sectional view showing an embodiment of the laminated polarizing film of the present invention.
2 is a cross-sectional view showing an embodiment of the laminated polarizing film of the present invention.
3 is a cross-sectional view showing an embodiment of the laminated polarizing film of the present invention.
4 is a cross-sectional view showing an embodiment of the laminated polarizing film of the present invention.

EMBODIMENT OF THE INVENTION It demonstrates below, referring drawings about the embodiment of the laminated polarizing film of this invention.

1 to 4 are cross-sectional views showing one embodiment of the laminated polarizing film of the present invention. The laminated polarizing film shown in FIG. 1A has a polarizing film (P) in which a transparent protective film (2) is formed on both surfaces of a polarizer (1) via an adhesive layer (b), and one side of the polarizing film (P) The optical film 3 is formed through the low-elastic adhesive layer (a) in the transparent protective film 2 of. The laminated polarizing film shown in FIG. 1B has a polarizing film (P) in which a transparent protective film (2) is formed only on one side of the polarizer (1) through an adhesive layer (b), and in the polarizing film (P) The optical film 3 is formed through the low-elastic adhesive layer (a) in the transparent protective film 2 of. In addition, in FIG. 1A, the optical film 3 is formed only in the transparent protective film 2 on one side of the polarizing film P through the low-elastic adhesive layer (a), but in the transparent protective film 2 on both sides. The optical film 3 can be formed through the low elastic adhesive layer (a). The laminated polarizing film of FIGS. 2 to 4 shows a case where the polarizing film (P) described in FIG. 1A is used in an aspect of the polarizing films (P1) to (P3).

The low-elastic adhesive layer (a) has a storage elastic modulus at 25°C of 3.0×10 ⁵ to 1.0×10 ⁸ Pa. By controlling the storage elastic modulus at 25°C of the low elastic adhesive layer (a) within the above range, a laminated polarizing film having good impact resistance and heat buckling property can be obtained. When the storage elastic modulus at 25°C is lower than 3.0×10 ⁵ Pa, sufficient cohesive strength of the low elastic adhesive layer (a) is not obtained, and the adhesiveness is lowered, which is not preferable. On the other hand, when the storage elastic modulus at 25°C is higher than 1.0×10 ⁸ Pa, the shock absorption property is inferior, and thus it is not preferable from the viewpoint of impact resistance. The storage elastic modulus at 25°C is preferably 1.0×10 ⁶ to 1.0×10 ⁷ Pa.

Further, the low elasticity adhesive layer (a) preferably has a storage elastic modulus at 85°C of 3.0×10 ⁵ to 1.0×10 ⁸ Pa. It is preferable to satisfy the heating durability by controlling the storage modulus at 85°C of the low elastic adhesive layer (a) within the above range. In particular, by making the storage modulus at 85°C higher than 3.0×10 ⁵ Pa, it is preferable to suppress the occurrence of foaming or peeling caused by vapor pressure at which the residual moisture of the polarizing film or the optical film gasifies. Moreover, by making the storage modulus at 85 degreeC lower than 1.0 × 10 ⁸ Pa, it is preferable to follow the adhesive layer to the dimensional change of a polarizing film and an optical film, and suppress the occurrence of peeling. The storage modulus at 85°C is preferably 1.0×10 ⁶ to 1.0×10 ⁷ Pa.

The thickness of the low-elastic adhesive layer (a) is 0.1 to 5 µm. The low-elastic adhesive layer (a) is capable of forming a thin layer, can satisfy the storage modulus in spite of being a thin layer, and obtain a laminated polarizing film having good heat buckling property. When the thickness is less than 0.1 µm, the cohesive force of the low-elastic adhesive layer (a) is not sufficiently obtained, and the adhesion is lowered, which is not preferable. On the other hand, when the thickness exceeds 5 µm, heat buckling property deteriorates, which is not preferable. The thickness of the low-elastic adhesive layer (a) is preferably 0.4 to 3 µm, and further preferably 0.7 to 2 µm from the viewpoint of a thin layer.

On the other hand, in the polarizing film (P) or (P'), the thickness of the adhesive layer (b) which laminates the polarizer 1 and the transparent protective film 2 is usually 0.1 to 25 µm from the viewpoint of adhesiveness.

The polarizing film (P1) in the laminated polarizing film of FIG. 2 is a case where the adhesive layer (b1) is used as both the adhesive layers (b) on both sides of the polarizer (1). The adhesive layer (b1) can be used having a storage elastic modulus at 85°C of 1.0×10 ⁶ to 1.0×10 ¹⁰ Pa and a thickness satisfying 0.03 to 3 μm. It is preferable to control the storage modulus and thickness of the adhesive layer (b1) within the above ranges from the viewpoint of suppressing polarizer cracks during the heat shock cycle test. The adhesive layer (b1) preferably has a storage elastic modulus at 85° C. of 1.0×10 ⁷ to 5.0×10 ⁹ Pa, and further preferably 1.0×10 ⁸ to 1.0×10 ⁹ Pa. Further, the thickness of the adhesive layer (b1) is preferably 0.04 to 2 µm, and further preferably 0.05 to 1.5 µm from the viewpoint of a thin layer.

In addition, the adhesive layer (b1) preferably has a storage elastic modulus at 25°C of 5.0×10 ⁷ to 1.0×10 ¹⁰ Pa, 1.0×10 ⁸ to 7.0×10 ⁹ Pa, and further 5.0×10 ⁸ It is preferably -5.0 × 10 ⁹ Pa.

The polarizing films (P2) and (P3) in the laminated polarizing films of FIGS. 3 and 4 have an adhesive layer (b1) as an adhesive layer (b) on one side of the polarizer 1, and the adhesive layer ( This is the case where the adhesive layer (b2) is used as b). In FIG. 3, an adhesive layer (b1) is used as the adhesive layer (b) for laminating the transparent protective film 2 on the side on which the low elasticity adhesive layer (a) is laminated, and in FIG. 4, the low elasticity adhesive layer (a) The adhesive layer (b2) is used as the adhesive layer (b) for laminating the transparent protective film 2 on the side to which) is laminated.

Also in the adhesive layer (b1) of FIG. 3 and FIG. 4, the storage elastic modulus at 85°C is 1.0 × 10 ⁶ to 1.0 × 10 ¹⁰ Pa, and the thickness is 0.03 to 3, similarly to the adhesive layer (b1) of FIG. What satisfies ㎛ can be used. In addition, the adhesive layer (b1) preferably has a storage elastic modulus at 25 ℃ of ^{5.0 × 10 7 ~ 1.0 × 10} 10 ㎩. The preferred ranges of the storage modulus and thickness of the adhesive layer (b1) are the same as those described in FIG. 2.

3, the adhesive layer (b2) of Figure 4, the storage modulus ^{1.0 × 10 4 ~ 1.0 × 10} 8 ㎩ in 85 ℃, can be used to meet the thickness of 0.1 ~ 25 ㎛. The adhesive layer (b2) preferably has a storage elastic modulus at 85°C of 5.0×10 ⁴ to 5.0×10 ⁷ Pa, and more preferably 3.0×10 ⁵ to 1.0×10 ⁷ Pa. The thickness of the adhesive layer (b2) is preferably 0.5 to 15 µm, and further preferably 0.8 to 5 µm.

Further, the adhesive layer (b2) preferably has a storage elastic modulus at 25°C of 1.0 × 10 ⁴ to 1.0 × 10 ⁸ Pa, 5.0 × 10 ⁴ to 7.0 × 10 ⁷ Pa, and furthermore 1.0 × 10 ⁵ It is preferably-1.0 × 10 ⁷ Pa.

Controlling the storage elastic modulus and thickness of the adhesive layers (b1) and (b2) within the above ranges is preferable in that it is possible to suppress a polarizer crack during a heat shock cycle test, and that impact resistance is more satisfied.

In addition, in the polarizing film P in the laminated polarizing film of FIG. 1B, the transparent protective film 2 is formed only on one side of the polarizer 1 via the adhesive layer (b). As the adhesive layer (b) in the polarizing film (P) of FIG. 1B, when the polarizing film (P) is provided for a heating test or a freezing cycle test, the expansion and contraction of the polarizer 1 is suppressed, and further, knick, etc. From the viewpoint of suppressing the occurrence of, it is preferable to use the adhesive layer (b1) having a high modulus of elasticity.

<Low elasticity adhesive layer (a)>

The low-elastic adhesive layer (a) is a cured product layer formed by solidification by curing a low-elastic adhesive. As the low-elastic adhesive, a liquid composition capable of forming a cured product layer having a storage elastic modulus at 25°C of 3.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa is used. The low-elastic adhesive is used to bond and integrate the two adherends. In the case of bonding of two adherends, after applying the composition to one or both of the two adherends, bonding is performed, and thereafter, by applying energy, the composition is cured and solidified. Layer (a) is formed.

The low-elastic adhesive layer (a) has a storage elastic modulus at 25° C. as described above and has a storage elastic modulus of 3.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa, and can satisfy the storage elastic modulus in formation of the low-elastic adhesive layer (a). Adhesive is used. The low-elastic adhesive layer (a) is not particularly limited as long as it is optically transparent, and various types of water-based, solvent-based, hot-melt-based, and active energy ray-curable ones are used.

It is preferable to form the said low elastic adhesive layer (a) as a hardened|cured material layer obtained by irradiating an active energy ray-curable adhesive with an active energy ray, for example. As the active energy ray-curable adhesive, an electron beam-curable or ultraviolet-curable adhesive may be used. As ultraviolet curable adhesives, radical polymerization curable adhesives and cationic polymerization adhesives can be broadly classified.

Examples of the curable component of the radical polymerization curable adhesive include a compound having a (meth)acryloyl group and a radical polymerizable compound having a vinyl group. Any of monofunctional or bifunctional or more polyfunctional can be used as these curable components. Moreover, these curable components can be used individually by 1 type or in combination of 2 or more types. As these curable components, a compound having a (meth)acryloyl group is preferable, for example.

Examples of the curable component of the cation polymerization curable adhesive include an epoxy group, an oxetanyl group, or a compound having a vinyl group. The compound having an epoxy group is not particularly limited as long as it has at least one epoxy group in the molecule, and various generally known curable epoxy compounds can be used. As a preferred epoxy compound, a compound having at least two epoxy groups in the molecule and at least one aromatic ring (hereinafter referred to as ``aromatic epoxy compound'') or at least two epoxy groups in the molecule, at least one of which is an alicyclic Examples thereof include compounds formed between adjacent two carbon atoms constituting the formula ring.

The active energy ray-curable adhesive contains substantially no organic solvent, and a liquid substance having a viscosity of 1 to 100 cp/25°C is used. By using such a liquid substance, it is possible to form a thin-layer low-elastic adhesive layer (a) having a thickness of 0.1 to 5 µm. The point that the liquid adhesive is used in the formation of the low elastic adhesive layer (a) differs from that the adhesive used for forming the adhesive layer does not exhibit a liquid substance, and from this point also the difference between the adhesive layer and the adhesive layer. Is clear. The viscosity is preferably 5 to 100 cp/25°C, and more preferably 10 to 70 cp/25°C. The "substantially free from organic solvent" means that the active energy ray-curable adhesive can contain an organic solvent in a range of 10% by weight or less with respect to the total amount of the active energy ray-curable adhesive. In addition, the content of the organic solvent is preferably 5% by weight or less, and more preferably 3% by weight or less. Here, the organic solvent is a liquid with a flash point of 40°C or less. The active energy ray-curable adhesive does not need to contain an organic solvent.

As the active energy ray-curable adhesive, it is preferable to use one containing a radical polymerizable compound as a curable component. As the radical polymerizable compound, any of a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound (A) can be used. When the total amount of the radical polymerizable compound is 100% by weight, the active energy ray-curable adhesive preferably contains a polyfunctional radical polymerizable compound (A) in a proportion of more than 5% by weight and 50% by weight or less. Do. The active energy ray-curable adhesive may contain another radically polymerizable compound in a range in which the low elastic adhesive layer (a) satisfies the above storage modulus.

<Multifunctional radical polymerizable compound (A)>

The polyfunctional radically polymerizable compound (A) is a compound having at least two radically polymerizable functional groups having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the polyfunctional radical polymerizable compound (A) include tetraethylene glycol diacrylate (Tg of homopolymer: 50°C, hereinafter only described as Tg), polyethylene glycol diacrylate, polypropylene glycol diacrylate (n = 3, Tg 69 ℃), (n = 7, Tg: -8 ℃), (n = 12, Tg: -32 ℃) polyalkylene glycol-based diacrylate, neopentyl glycol diacrylate (Tg : 117 ℃), 3-methyl-1,5-pentanediol diacrylate (Tg: 105 ℃), 1,6-hexanediol diacrylate (Tg: 63 ℃), 1,9-nonanediol diacrylate (Tg: 68 ℃), 2-methyl-1,8-octanediol diacrylate and 1,9-nonanediol diacrylate mixture (Tg: 88 ℃), dimethylol-tricyclodecane diacrylate (Tg: 75 ℃), bisphenol A EO adduct diacrylate (Tg: 75 ℃), bisphenol F EO modified (n = 2) diacrylate (Tg: 75 ℃), bisphenol A EO modified (n = 2) diacrylic Rate (Tg: 75°C), isocyanuric acid EO-modified diacrylate (Tg: 166°C), trimethylolpropane triacrylate (Tg: 250°C or higher), trimethylolpropane PO-modified triacrylate (n = 1 , Tg: 120 ℃), (n = 2, Tg: 50 ℃), trimethylolpropane EO modified triacrylate (n = 1, Tg not measured), (n = 2, Tg: 53 ℃), isocyanur Acid EO-modified di and triacrylate (di: 30-40%, Tg: 250°C or higher), (di: 3-13%, Tg: 250°C or higher), pentaerythritol tri and tetraacrylate (tri: 65 -70%, Tg: 250℃ or more), (Tree: 55-63%, Tg: 250℃ or more), (Tree: 40-60%, Tg: 250℃ or more), (Tree: 25-40%, Tg : 250°C or more), (Tree: less than 10%, Tg: 250°C or more), Ditrimethylolpropanetetraacrylate (Tg: 250 ℃ or higher), dipentaerythritol penta and hexaacrylate (penta: 50-60%, Tg: 250 ℃ or higher), (penta: 40-50%, Tg: 250 ℃ or higher), (penta: 30-40%, Tg: 250 ℃ or higher), (penta: 25-35%, Tg: 250 ℃ or higher), (penta: 10-20%, Tg: 250 ℃ or higher), and (Meth)acrylates corresponding to these are mentioned. In addition, oligomer (meth)acrylates, such as various polyurethane (meth)acrylate, polyester (meth)acrylate, and polyepoxy (meth)acrylate, etc. are mentioned. In addition, as the polyfunctional radical polymerizable compound (A), a commercial item can also be preferably used, for example, light acrylate 4EG-A, light acrylate 9EG-A, light acrylate NP-A, light acrylate MPD-A , Light acrylate 1.6HX-A, light acrylate 1.9ND-A, light acrylate MOD-A, light acrylate DCP-A, light acrylate BP-4EAL or higher (manufactured by Kyoeisha Chemical Co., Ltd.), Aaronics M- 208, M-211B, M-215, M-220, M-225, M-270, M-240, M-309, M-310, M-321, M-350, M-360, M-313, M-315, M-306, M-305, M-303, M-452, M-450, M-408, M-403, M-400, M-402, M-404, M-406, M- 405, M-1100, M-1200, M-6100, M-6200, M-6250, M-6500, M-7100, M-7300, M-8030, M-8060, M-8100, M-8530, M-8560, M-9050 (manufactured by Dong-A Synthetic Corporation), SR-531 (manufactured by SARTOMER), CD-536 (manufactured by SARTOMER), and the like. As for the polyfunctional radical polymerizable compound (A), it is preferable that Tg of a homopolymer satisfies -40-100 degreeC.

As the polyfunctional radical polymerizable compound (A), it is more preferable that the distance between crosslinking points is long. By increasing the distance between crosslinking points, the amount of bulk deformation of the low-elastic adhesive layer (a) increases, and a laminated polarizing film having particularly excellent impact resistance can be obtained. As the polyfunctional radical polymerizable compound (A) having a long distance between crosslinking points, a bifunctional (meth)acrylate having two (meth)acryloyl groups is preferable. The weight average molecular weight of the bifunctional (meth)acrylate is preferably from 200 to 4000, more preferably from 400 to 2000, and most preferably from 500 to 1000. When the weight average molecular weight is too large, the viscosity of the active energy ray-curable adhesive increases, the coating thickness becomes non-uniform, resulting in poor appearance, or there is a tendency that bubbles enter in the bonding step to cause poor appearance. From the above viewpoint, it is preferable that the bifunctional (meth)acrylate has a linear structure. In addition, a trifunctional (meth)acrylate having three or more (meth)acryloyl groups has a shorter distance between crosslinking points than a bifunctional (meth)acrylate. From the viewpoint of the effect (impact resistance) of the present invention, a bifunctional (meth)acrylate is preferable.

Examples of the difunctional (meth)acrylate having a weight average molecular weight of 200 to 4000 include polyalkylene glycol di(meth)acrylates such as polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate. ) Oligomer (meth)acrylates, such as acrylate, polyester (meth)acrylate, polyurethane (meth)acrylate, and polyepoxy (meth)acrylate, etc. are mentioned.

The ratio of the polyfunctional radically polymerizable compound (A) is preferably 1 to 65% by weight when the total amount of the radically polymerizable compound in the active energy ray-curable adhesive is 100% by weight. It is preferable to set the said ratio to 1 weight% or more in order to satisfy|fill the impact resistance, heat buckling property, and polarizer crack of the low elastic adhesive layer (a).

As the polyfunctional radical polymerizable compound (A), all or part of the bifunctional (meth)acrylate having the weight average molecular weight of 200 to 4000 can be used. The ratio of the bifunctional (meth)acrylate having a weight average molecular weight of 200 to 4000 is preferably 1 to 65% by weight, when the total amount of the radical polymerizable compound in the active energy ray-curable adhesive is 100% by weight, It is more preferable that it is 2-50 weight%, and it is most preferable that it is 3-20 weight%. When the above ratio is large, the amount of bulk deformation of the low-elastic adhesive layer (a) becomes small, the peeling force decreases, and the impact resistance tends to decrease.

<Alkyl (meth)acrylate (B) having an alkyl group having 2 to 18 carbon atoms>

The active energy ray-curable adhesive used to form the low-elastic adhesive layer (a) is a monofunctional radical polymerizable compound of a radical polymerizable compound, and is an alkyl (meth)acrylate (B) having an alkyl group having 2 to 18 carbon atoms. It may contain. As the alkyl (meth)acrylate (B), those having 1 to 18 carbon atoms of a linear or branched alkyl group can be illustrated. For example, examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, Nonyl group, decyl group, isodecyl group, dodecyl group, isomyristol group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, stearyl group, isostearyl group, etc. I can. These can be used alone or in combination. It is preferable that the alkyl (meth)acrylate (B) has 3 to 18 carbon atoms in the alkyl group. As for the alkyl (meth)acrylate (B), it is preferable that Tg of a homopolymer satisfies -80 to 60°C from the viewpoints of durability against peeling in a drop test and water resistance. For example, methyl acrylate (Tg: 8 °C), ethyl acrylate (Tg: -20 °C), n-propyl acrylate (Tg: 8 °C), n-butyl acrylate (Tg: -45 °C), Isobutyl acrylate (Tg: -26 ℃), t-butyl acrylate (Tg: 14 ℃), isoamyl acrylate (Tg: -45 ℃), cyclohexyl acrylate (Tg: 8 ℃), 2-ethyl Hexyl acrylate (Tg: -55 ℃), n-octyl acrylate (Tg: -65 ℃), isooctyl acrylate (Tg: -58 ℃), isononyl acrylate (Tg: -58 ℃), lauryl It is preferable to use an alkyl acrylate such as acrylate (Tg: 15°C), stearyl acrylate (Tg: 30°C), and isostearyl acrylate (Tg: -18°C).

The ratio of the alkyl (meth)acrylate (B) is 60% by weight or less from the viewpoint of satisfying the impact resistance and heating buckling property when the total amount of the radical polymerizable compound in the active energy ray-curable adhesive is 100% by weight. It is preferable to use it in a ratio of. The ratio is preferably 10 to 50% by weight, and more preferably 20 to 40% by weight.

<(meth)acrylate (C) having a hydroxyl group>

The active energy ray-curable adhesive used for formation of the low-elastic adhesive layer (a) may contain (meth)acrylate (C) having a hydroxyl group as a monofunctional radical polymerizable compound of the radical polymerizable compound. As the (meth)acrylate (C) having a hydroxyl group, one having a (meth)acryloyl group and a hydroxyl group can be used. As a specific example of the (meth)acrylate (C) having a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth) Alkyl groups such as acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate C2-C12 hydroxyalkyl (meth)acrylate, (4-hydroxymethylcyclohexyl)-methylacrylate, etc. are mentioned. In the (meth)acrylate (C) having a hydroxyl group, it is preferable that the Tg of the homopolymer satisfies -80 to 40°C in terms of durability against peeling in a drop test. For example, it is preferable to use hydroxyethyl acrylate (Tg: -15°C), hydroxypropyl acrylate (Tg: -7°C), hydroxybutyl acrylate (Tg: -32°C), and the like.

As the (meth)acrylate (C) having a hydroxyl group, one having a long chain length between a hydroxyl group and a (meth)acryloyl group can be used. When the chain length between the hydroxyl group and the (meth)acryloyl group is long, the hydroxyl group is more likely to be oriented to the adhered film, and it is preferable that the polarity of the hydroxyl group provides more effective adhesion. As the (meth)acrylate (C) having a hydroxyl group and having a long chain length between the hydroxyl group and the (meth)acryloyl group and having a hydroxyl group, a hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000 It is desirable. The weight average molecular weight of the hydroxyl group-containing monofunctional (meth)acrylate is more preferably 200 to 2000, and most preferably 300 to 1000. Regarding the hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000, the chain length between the hydroxyl group and the (meth)acryloyl group is preferably long, and the hydroxyl group and the (meth)acryloyl group are at both ends (especially It is preferable to have a linear structure).

When the weight average molecular weight of the (meth)acrylate (C) having a hydroxyl group is too large, the viscosity of the active energy ray-curable adhesive increases, the coating thickness becomes non-uniform, resulting in poor appearance, or bubbles enter in the bonding process, resulting in appearance It is not preferable because it may cause a defect. Moreover, since the number of hydroxyl groups is relatively reduced, the effect of imparting adhesiveness due to the polarity of the hydroxyl groups becomes difficult to obtain, which is not preferable. As a hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000, a weight average molecular weight of 160 to 3000 is satisfied among the hydroxyalkyl (meth)acrylates described above, and polyethylene glycol mono(meth) Polyalkylene glycol mono (meth) acrylates such as acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol mono (meth) acrylate, and hydroxyalkyl (meth) acrylates described above B. Caprolactone modified product of (4-hydroxymethylcyclohexyl)-methylacrylate, etc. are mentioned. As the caprolactone modified product, a caprolactone adduct of hydroxyethyl (meth)acrylate is preferably used, and the amount of caprolactone added is particularly preferably 1 to 5 mol.

The ratio of the (meth)acrylate (C) having a hydroxyl group is 70 weight from the viewpoint of satisfying the impact resistance and heat buckling property when the total amount of the radical polymerizable compound in the active energy ray-curable adhesive is 100% by weight. It is preferable to use it in a ratio of% or less. When the above ratio is large, the influence of the hydrophilicity of the hydroxyl group increases, and the water resistance such as peeling in a humidified environment deteriorates, which is not preferable. In the case of using hydroxyalkyl (meth)acrylate or (4-hydroxymethylcyclohexyl)-methylacrylate as the (meth)acrylate (C) having a hydroxyl group, the ratio is 10 to 60% by weight. It is preferable, and further, it is preferable that it is 20-50 weight%. In the case of using a hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000 as the (meth)acrylate (C) having a hydroxyl group, the total amount of the radical polymerizable compound in the active energy ray-curable adhesive When it is set as 100 weight%, it is preferable that it is 1 to 70 weight%, and it is more preferable that it is 30 to 60 weight%.

<Measurement of weight average molecular weight>

The weight average molecular weight of the bifunctional (meth)acrylate and the hydroxyl group-containing monofunctional (meth)acrylate can be measured by GPC (gel permeation chromatography).

Detector: Differential Refractometer (RI)

· Standard sample: Polystyrene

<Other radical polymerizable compounds>

The active energy ray-curable adhesive used for formation of the low-elastic adhesive layer (a) may contain other radical polymerizable compounds other than the above as a radical polymerizable compound. As other radically polymerizable compounds, it is preferable to have a polar group from the viewpoint of improving the adhesiveness, durability, and water resistance of the adhesive layer in a more balanced manner. As monofunctional radical polymerizable compounds of other radically polymerizable compounds, for example, hydroxyethylacrylamide, N-methylolacrylamide, acryloylmorpholine, N-methoxymethylacrylamide, N-ethoxymethyl Acrylamide, N-vinyl caprolactam, etc. are mentioned.

The ratio of other radical polymerizable compounds is used in a ratio of 30% by weight or less from the viewpoint of adhesion, durability and water resistance of the adhesive layer when the total amount of the radical polymerizable compound in the active energy ray-curable adhesive is 100% by weight. It is desirable to do. The ratio is preferably 2 to 25% by weight, and more preferably 5 to 20% by weight.

<Silane coupling agent (D) not having a polymerization group>

The active energy ray-curable adhesive used for formation of the low-elastic adhesive layer (a) may contain a silane coupling agent (D) in addition to the radical polymerizable compound. As the silane coupling agent (D), a silane coupling agent having no radical polymerizable functional group is preferable. The silane coupling agent which does not have a radical polymerizable functional group acts on the surface of the polarizer and can impart additional water resistance.

As a specific example of the silane coupling agent which does not have a radical polymerizable functional group, a silane coupling agent which has an amino group is mentioned. Specific examples of the silane coupling agent having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ -Aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrie Oxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2-aminoethyl)aminoethyl)aminopropyl Trimethoxysilane, γ-(6-aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ- Ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N- Cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N'-bis[ Amino group-containing silanes such as 3-(trimethoxysilyl)propyl]ethylenediamine; Ketimine-type silanes, such as N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, are mentioned.

Examples of the silane coupling agent having an amino group include γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, and γ- (2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)- 1-propanamine is preferred.

Specific examples of the silane coupling agent having no radically polymerizable functional group other than the silane coupling agent having an amino group include 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltri Methoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate propyltriethoxysilane, imidazole silane, etc. are mentioned.

In addition, as the silane coupling agent (D), as an active energy ray-curable compound, vinyl trichlorsilane, vinyl trimethoxysilane, vinyl triethoxysilane, 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldime Methoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane. .

As for the silane coupling agent (D), only 1 type may be used and multiple types may be combined and used for it. The blending amount of the silane coupling agent (D) not having a radically polymerizable functional group is usually 20 parts by weight or less, preferably 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive. It is preferably 0.05 to 15 parts by weight, and more preferably 0.1 to 10 parts by weight. In the case of a blending amount exceeding 20 parts by weight, the storage stability of the adhesive may be deteriorated.

<Acrylic oligomer (E) obtained by polymerizing a (meth)acrylic monomer>

The active energy ray-curable adhesive used to form the low-elastic adhesive layer (a) may contain, in addition to a radical polymerizable compound, an acrylic oligomer (E) obtained by polymerizing a (meth)acrylic monomer. By containing the acrylic oligomer (E) in the active energy ray-curable adhesive, curing shrinkage when irradiating and curing the composition with an active energy ray is reduced, such as an adhesive, a polarizing film (P), and an optical film (3). The interfacial stress of the adherend can be reduced. As a result, it is possible to suppress a decrease in adhesion between the adhesive layer and the adherend.

Since the active energy ray-curable adhesive is preferably of low viscosity in consideration of workability and uniformity at the time of coating, the acrylic oligomer (E) obtained by polymerizing a (meth)acrylic monomer is also preferably of low viscosity. As an acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer, the weight average molecular weight (Mw) is preferably 15000 or less, more preferably 10000 or less, and particularly preferably 5000 or less. On the other hand, in order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer (E) is preferably 500 or more, more preferably 1000 or more, and particularly preferably 1500 or more. . As the (meth)acrylic monomer constituting the acrylic oligomer (E), specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) Acrylate, 2-methyl-2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylic Rate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, Cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, etc. (Meth)acrylic acid (C1-C20) alkyl esters of, for example, cycloalkyl (meth)acrylate (for example, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), are Alkyl (meth) acrylate (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (e.g., 2-isobornyl (meth) acrylate, 2-norbornyl methyl ( Meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylic acid esters (For example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), alkoxy group or phenoxy group Containing (meth)acrylic acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth) )Acrylate, ethylcarbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic esters (eg glycidyl (meth)acrylate, etc.), halogen-containing (Meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2, 2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth) ) Acrylate), alkylaminoalkyl (meth)acrylate (for example, dimethylaminoethyl (meth)acrylate), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (E) include "ARUFON" manufactured by Dong-A Synthetic Corporation, "Actflow" manufactured by Soken Chemical Corporation, and "JONCRYL" manufactured by BASF Japan.

It is preferable that the blending amount of the acrylic oligomer (E) is usually 30 parts by weight or less with respect to 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive. When the content of the acrylic oligomer (E) in the composition is too large, the decrease in the reaction rate when the composition is irradiated with an active energy ray is severe, resulting in poor curing. On the other hand, in order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer a), it is preferable to contain 3 parts by weight or more of the acrylic oligomer (E) in the composition, and more preferably 5 parts by weight or more.

<The radical polymerizable compound (F) having an active methylene group and a radical polymerization initiator (G) having a hydrogen extraction function>

The active energy ray-curable adhesive used to form the low-elastic adhesive layer (a), in addition to the radical polymerizable compound, further includes a radical polymerizable compound (F) having an active methylene group, and a radical polymerization initiator having a hydrogen drawing action ( G) may contain. According to this configuration, the adhesion of the low-elastic adhesive layer (a) is remarkably improved, especially even immediately after pulling out from a high humidity environment or water (non-dried state). Although this reason is not clear, the following causes are considered. In short, the radical polymerizable compound (F) having an active methylene group is polymerized with other radical polymerizable compounds constituting the low elastic adhesive layer (a), while the main chain of the base polymer in the low elastic adhesive layer (a) and/ Alternatively, it is incorporated into the side chain to form a low elastic adhesive layer (a). In such a polymerization process, if a radical polymerization initiator (G) having a hydrogen drawing function is present, hydrogen from the radical polymerizable compound (F) having an active methylene group is formed while the base polymer constituting the low elastic adhesive layer (a) is formed. Is drawn out, and a radical is generated in the methylene group. Then, the methylene group in which the radical is generated and the hydroxyl group of a polarizer such as PVA react, and a covalent bond is formed between the low-elastic adhesive layer (a) and the polarizer (1). As a result, even in a non-dried state, it is estimated that the adhesiveness of the adhesive layer which the polarizing film has is significantly improved.

The radically polymerizable compound (F) having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the terminal or in the molecule and further having an active methylene group. As an active methylene group, an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group, etc. are mentioned, for example. Specific examples of the radical polymerizable compound (F) having an active methylene group include, for example, 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, and 2-acetoacetoxy- Acetoacetoxyalkyl (meth)acrylate such as 1-methylethyl (meth)acrylate; 2-Ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxy Butyl)acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide, and the like.

Examples of the radical polymerization initiator (G) having a hydrogen drawing action include a thioxanthone radical polymerization initiator, a benzophenone radical polymerization initiator, and the like. As a thioxanthone-based radical polymerization initiator, a compound represented by the following general formula (1);

[Formula 1]

(In the formula, R ¹ and R ² represent -H, -CH _2b H ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different).

As a specific example of the compound represented by General formula (1), thioxanthone, dimethyl thioxanthone, diethyl thioxanthone, isopropyl thioxanthone, chloro thioxanthone, etc. are mentioned, for example. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are -CH _2b H ₃ is particularly preferable.

Moreover, in the said active energy ray-curable adhesive, in addition to the photoinitiator of general formula (1) as a photoinitiator, it is a compound further represented by the following general formula (2);

[Formula 2]

(In the formula, R ³ , R ⁴ and R ⁵ represent -H, -CH _3b H _2b H ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different) desirable. By using the photopolymerization initiator of the general formula (1) and the general formula (2) together, the reaction becomes highly efficient due to these photosensitization reactions, and the adhesiveness of the adhesive layer is particularly improved.

As described above, in the present invention, in the presence of a radical polymerization initiator (G) having a hydrogen drawing action, a radical is generated in the methylene group of the radically polymerizable compound (F) having an active methylene group, and such methylene group and hydroxyl group Reacts and forms a covalent bond. Therefore, the radical polymerizable compound (F) having an active methylene group generates a radical in the methylene group of the radical polymerizable compound (F) having an active methylene group, and in order to sufficiently form such a covalent bond, the radical in the active energy ray-curable adhesive When the total amount of the polymerizable compound is 100 parts by weight, it is preferable to contain 1 to 30 parts by weight, and more preferably 3 to 30 parts by weight. If the radical polymerizable compound (F) having an active methylene group is less than 1 part by weight, the effect of improving the adhesion in a non-dried state is low, and water resistance may not be sufficiently improved, and if it exceeds 50 parts by weight, curing of the adhesive layer There is a case of failure. In addition, the radical polymerization initiator (G) having a hydrogen drawing action is preferably contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive, and furthermore, 0.3 to 9 It is more preferable to contain it in parts by weight. When the radical polymerization initiator (G) having a hydrogen drawing action is less than 0.1 part by weight, the hydrogen drawing reaction may not proceed sufficiently, and if it exceeds 10 parts by weight, it may not be completely dissolved in the composition.

<mine generator (H)>

The active energy ray-curable adhesive used for formation of the low-elastic adhesive layer (a) may further contain a photoacid generator (H) in addition to the radical polymerizable compound. When a photoacid generator is contained in an active energy ray-curable resin composition, the water resistance and durability of an adhesive layer can be improved drastically compared with the case where a photoacid generator is not contained. The photoacid generator (H) can be represented by the following general formula (3).

General Formula (3)

[Formula 3]

(Where, L ⁺ is representative of any of the onium cation addition, X ^{-. _{Is, PF 6 -, SbF 6 -}} , AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dt O carbamate anion, SCN ^- represents a counter anion selected from the group consisting of from a).

As the structure of the onium cation preferable as the onium cation L ⁺ constituting the general formula (3), onium cation selected from the following general formulas (4) to (12) can be mentioned.

General Formula (4)

[Formula 4]

General Formula (5)

[Formula 5]

General Formula (6)

[Formula 6]

General Formula (7)

[Formula 7]

General Formula (8)

[Formula 8]

General Formula (9)

[Formula 9]

General Formula (10)

[Formula 10]

General Formula (11)

[Formula 11]

General Formula (12)

[Formula 12]

(In the formulas (4)-(12), provided that R ¹ , R ² and R ³ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted Aryl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted heterocyclic oxy group, substituted or unsubstituted acyl group, substituted or unsubstituted Represents a substituted carbonyloxy group, a substituted or unsubstituted oxycarbonyl group, or a group selected from halogen atoms R ⁴ represents the same group as the groups described for R ¹ , R ² and R ^3. R ⁵ represents a substituted or unsubstituted oxycarbonyl group. Represents an unsubstituted alkyl group or a substituted or unsubstituted alkylthio group R ⁶ and R ⁷ each independently represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxyl group R is a halogen atom, a hydroxyl group, or Carboxyl group, mercapto group, cyano group, nitro group, substituted or unsubstituted carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted aryl group, substituted or unsubstituted hetero Cyclic group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted heterocyclic oxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or Represents any of an unsubstituted heterocyclic thio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted carbonyloxy group, and a substituted or unsubstituted oxycarbonyl group Ar ⁴ and Ar ⁵ are substituted or unsubstituted Represents either an aryl group or a substituted or unsubstituted heterocyclic group, X represents an oxygen or sulfur atom, i represents an integer of 0 to 5. j represents an integer of 0 to 4. k represents an integer of 0 to 4 Represents an integer of 3. In addition, adjacent R to each other, Ar ⁴ and Ar ⁵ , R ² and R ³ , R ² and R ⁴ , R ³ and R ⁴ , R ¹ and R ² , R ¹ and R ³ , R ¹ And R ⁴ , R ¹ and R, or R ¹ And R ⁵ may be a cyclic structure bonded to each other.)

Onium cation (sulfonium cation) corresponding to general formula (4):

Dimethylphenylsulfonium, dimethyl(o-fluorophenyl)sulfonium, dimethyl(m-chlorophenyl)sulfonium, dimethyl(p-bromophenyl)sulfonium, dimethyl(p-cyanophenyl)sulfonium, dimethyl( m-nitrophenyl)sulfonium, dimethyl(2,4,6-tribromophenyl)sulfonium, dimethyl(pentafluorophenyl)sulfonium, dimethyl(p-(trifluoromethyl)phenyl)sulfonium, dimethyl (p-hydroxyphenyl)sulfonium, dimethyl(p-mercaptophenyl)sulfonium, dimethyl(p-methylsulfinylphenyl)sulfonium, dimethyl(p-methylsulfonylphenyl)sulfonium, dimethyl(o-acetyl) Phenyl) sulfonium, dimethyl (o-benzoylphenyl) sulfonium, dimethyl (p-methylphenyl) sulfonium, dimethyl (p-isopropylphenyl) sulfonium, dimethyl (p-octadecylphenyl) sulfonium, dimethyl (p- Cyclohexylphenyl)sulfonium, dimethyl(p-methoxyphenyl)sulfonium, dimethyl(o-methoxycarbonylphenyl)sulfonium, dimethyl(p-phenylsulfanylphenyl)sulfonium, (7-methoxy-2 -Oxo-2H-chromen-4-yl)dimethylsulfonium, (4-methoxynaphthalen-1-yl)dimethylsulfonium, dimethyl (p-isopropoxycarbonylphenyl)sulfonium, dimethyl (2-naph) Tyl) sulfonium, dimethyl (9-anthryl) sulfonium, diethylphenylsulfonium, methylethylphenylsulfonium, methyldiphenylsulfonium, triphenylsulfonium, diisopropylphenylsulfonium, diphenyl (4- Phenylsulfanyl-phenyl)-sulfonium, 4,4'-bis(diphenylsulfonium)diphenylsulfide, 4,4'-bis[di[(4-(2-hydroxy-ethoxy)-phenyl] )]Sulfonium]]diphenylsulfide, 4,4'-bis(diphenylsulfonium)biphenylene, diphenyl(o-fluorophenyl)sulfonium, diphenyl(m-chlorophenyl)sulfonium, Diphenyl (p-bromophenyl) sulfonium, diphenyl (p-cyanophenyl) sulfonium, diphenyl (m-nitrophenyl) sulfonium, diphenyl (2,4,6-tribromophenyl) alcohol Phonium, diphenyl (pentafluorophenyl) sulfonium, diphenyl (p-(trifluoromethyl) phenyl) sulfonium, diphenyl (p-hydroxyphenyl) sulfonium, diphenyl (p-mercaptophenyl) Sulfonium, diphenyl (p-methylsulfinylphenyl) sulfonium, diphenyl (p-methylsulfonylphenyl) sulfonium, diphenyl (o-acetylphenyl) sulfonium, diphenyl (o-benzoylphenyl) sulfonium , Diphenyl (p-methylphenyl) sulfonium, diphenyl (p-isopropylphenyl) sulfonium, diphenyl (p-octadecylphenyl) sulfonium, diphenyl (p-cyclohexylphenyl) sulfo Nium, diphenyl (p-methoxyphenyl) sulfonium, diphenyl (o-methoxycarbonylphenyl) sulfonium, diphenyl (p-phenylsulfanylphenyl) sulfonium, (7-methoxy-2-oxo -2H-chromen-4-yl)diphenylsulfonium, (4-methoxynaphthalen-1-yl)diphenylsulfonium, diphenyl(p-isopropoxycarbonylphenyl)sulfonium, diphenyl(2 -Naphthyl)sulfonium, diphenyl(9-anthryl)sulfonium, ethyldiphenylsulfonium, methylethyl(o-tolyl)sulfonium, methyldi(p-tolyl)sulfonium, tri(p-tolyl) Sulfonium, diisopropyl(4-phenylsulfanylphenyl)sulfonium, diphenyl(2-thienyl)sulfonium, diphenyl(2-furyl)sulfonium, diphenyl(9-ethyl-9Hcarbazole-3) -Il)sulfonium, etc. are mentioned, but are not limited to these.

Onium cation (sulfoxonium cation) corresponding to general formula (5):

Dimethylphenylsulfoxonium, dimethyl(o-fluorophenyl)sulfoxonium, dimethyl(m-chlorophenyl)sulfoxonium, dimethyl(p-bromophenyl)sulfoxonium, dimethyl(p-cyanophenyl)sulfur Foxonium, dimethyl(m-nitrophenyl)sulfoxonium, dimethyl(2,4,6-tribromophenyl)sulfoxonium, dimethyl(pentafluorophenyl)sulfoxonium, dimethyl(p-(trifluoro Methyl)phenyl)sulfoxonium, dimethyl(p-hydroxyphenyl)sulfoxonium, dimethyl(p-mercaptophenyl)sulfoxonium, dimethyl(p-methylsulfinylphenyl)sulfoxonium, dimethyl(p-methyl Sulfonylphenyl)sulfoxonium, dimethyl(o-acetylphenyl)sulfoxonium, dimethyl(o-benzoylphenyl)sulfoxonium, dimethyl(p-methylphenyl)sulfoxonium, dimethyl(p-isopropylphenyl)sulfoxonium Nium, dimethyl (p-octadecylphenyl) sulfoxonium, dimethyl (p-cyclohexylphenyl) sulfoxonium, dimethyl (p-methoxyphenyl) sulfoxonium, dimethyl (o-methoxycarbonylphenyl) sulfoxy Nium, dimethyl (p-phenylsulfanylphenyl) sulfoxonium, (7-methoxy-2-oxo-2H-chromen-4-yl) dimethylsulfoxonium, (4-methoxynaphthalen-1-yl) Dimethylsulfoxonium, dimethyl(p-isopropoxycarbonylphenyl)sulfoxonium, dimethyl(2-naphthyl)sulfoxonium, dimethyl(9-anthryl)sulfoxonium, diethylphenylsulfoxonium, methyl Ethylphenylsulfoxonium, methyldiphenylsulfoxonium, triphenylsulfoxonium, diisopropylphenylsulfoxonium, diphenyl(4-phenylsulfanyl-phenyl)-sulfoxonium, 4,4'-bis( Diphenylsulfoxonium)diphenylsulfide, 4,4'-bis[di[(4-(2-hydroxy-ethoxy)-phenyl)]sulfoxonium]diphenylsulfide, 4,4'- Bis(diphenylsulfoxonium)biphenylene, diphenyl(o-fluorophenyl)sulfoxonium, diphenyl(m-chlorophenyl)sulfoxonium, diphenyl(p-bromophenyl)sulfoxonium, Diphenyl (p-cyanophenyl) sulfoxonium, diphenyl (m-nitrophenyl) sulfoxonium, diphenyl (2,4,6-tribromophenyl) sulfoxonium, diphenyl (pentafluorophenyl) ) Sulfoxonium, diphenyl (p-(trifluoromethyl) phenyl) sulfoxonium, diphenyl (p-hydroxyphenyl) sulfoxonium, diphenyl (p-mercaptophenyl) sulfoxonium, diphenyl (p-methylsulfinylphenyl) sulfoxonium, diphenyl (p-methylsulfonylphenyl) sulfoxonium, diphenyl (o-acetylphenyl) sulfoxonium, diphenyl (o-benzoylphenyl) sulfoxonium, Diphenyl (p-methylphenyl) sulfoxonium, diphenyl (p-isopropylphenyl) sulfoxonium, diphenyl (p-octadecylphenyl) sulfoxonium, diphenyl (p-cyclohexylphenyl) sulfoxonium, diphenyl (p-methoxyphenyl) sulfoxonium, Diphenyl (o-methoxycarbonylphenyl) sulfoxonium, diphenyl (p-phenylsulfanylphenyl) sulfoxonium, (7-methoxy-2-oxo-2H-chromen-4-yl) diphenyl Sulfoxonium, (4-methoxynaphthalen-1-yl)diphenylsulfoxonium, diphenyl(p-isopropoxycarbonylphenyl)sulfoxonium, diphenyl(2-naphthyl)sulfoxonium, di Phenyl (9-anthryl)) sulfoxonium, ethyldiphenylsulfoxonium, methylethyl (o-tolyl) sulfoxonium, methyldi (p-tolyl) sulfoxonium, tri (p-tolyl) sulfoxonium , Diisopropyl(4-phenylsulfanylphenyl)sulfoxonium, diphenyl(2-thienyl)sulfoxonium, diphenyl(2-furyl)sulfoxonium, diphenyl(9-ethyl-9Hcarbazole- 3-yl) sulfoxonium etc. are mentioned, but it is not limited to these.

Onium cation (phosphonium cation) corresponding to general formula (6):

Examples of phosphonium cation:

Trimethylphenylphosphonium, triethylphenylphosphonium, tetraphenylphosphonium, triphenyl (p-fluorophenyl) phosphonium, triphenyl (o-chlorophenyl) phosphonium, triphenyl (m-bromophenyl) phosphonium , Triphenyl (p-cyanophenyl) phosphonium, triphenyl (m-nitrophenyl) phosphonium, triphenyl (p-phenylsulfanylphenyl) phosphonium, (7-methoxy-2-oxo-2H-chrome Men-4-yl) triphenylphosphonium, triphenyl (o-hydroxyphenyl) phosphonium, triphenyl (o-acetylphenyl) phosphonium, triphenyl (m-benzoylphenyl) phosphonium, triphenyl (p- Methylphenyl)phosphonium, triphenyl(p-isopropoxyphenyl)phosphonium, triphenyl(o-methoxycarbonylphenyl)phosphonium, triphenyl(1-naphthyl)phosphonium, triphenyl(9-anthryl) ) Phosphonium, triphenyl (2-thienyl) phosphonium, triphenyl (2-furyl) phosphonium, triphenyl (9-ethyl-9H carbazol-3-yl) phosphonium, etc. are mentioned. It is not limited.

Onium cation (pyridinium cation) corresponding to general formula (7):

Examples of pyridinium cation:

N-phenylpyridinium, N-(o-chlorophenyl)pyridinium, N-(m-chlorophenyl)pyridinium, N-(p-cyanophenyl)pyridinium, N-(o-nitrophenyl)pyridinium , N-(p-acetylphenyl)pyridinium, N-(p-isopropylphenyl)pyridinium, N-(p-octadecyloxyphenyl)pyridinium, N-(p-methoxycarbonylphenyl)pyridinium , N-(9-anthryl)pyridinium, 2-chloro-1-phenylpyridinium, 2-cyano-1-phenylpyridinium, 2-methyl-1-phenylpyridinium, 2-vinyl-1-phenyl Pyridinium, 2-phenyl-1-phenylpyridinium, 1,2-diphenylpyridinium, 2-methoxy-1-phenylpyridinium, 2-phenoxy-1-phenylpyridinium, 2-acetyl-1- (p-tolyl)pyridinium, 2-methoxycarbonyl-1-(p-tolyl)pyridinium, 3-fluoro-1-naphthylpyridinium, 4-methyl-1-(2-furyl)pyridinium , N-methylpyridinium, N-ethylpyridinium, and the like, but are not limited thereto.

Onium cation (quinolinium cation) corresponding to general formula (8):

Examples of quinolinium cation:

N-methylquinolinium, N-ethylquinolinium, N-phenylquinolinium, N-naphthylquinolinium, N-(o-chlorophenyl)quinolinium, N-(m-chlorophenyl)quinoli Nium, N-(p-cyanophenyl)quinolinium, N-(o-nitrophenyl)quinolinium, N-(p-acetylphenyl)quinolinium, N-(p-isopropylphenyl)quinoli Nium, N-(p-octadecyloxyphenyl)quinolinium, N-(p-methoxycarbonylphenyl)quinolinium, N-(9-anthryl)quinolinium, 2-chloro-1-phenyl Quinolinium, 2-cyano-1-phenylquinolinium, 2-methyl-1-phenylquinolinium, 2-vinyl-1-phenylquinolinium, 2-phenyl-1-phenylquinolinium, 1 ,2-diphenylquinolinium, 2-methoxy-1-phenylquinolinium, 2-phenoxy-1-phenylquinolinium, 2-acetyl-1-phenylquinolinium, 2-methoxycarbonyl -1-phenylquinolinium, 3-fluoro-1-phenylquinolinium, 4-methyl-1-phenylquinolinium, 2-methoxy-1-(p-tolyl)quinolinium, 2-phenoxy Cy-1-(2-furyl)quinolinium, 2-acetyl-1-(2-thienyl)quinolinium, 2-methoxycarbonyl-1-methylquinolinium, 3-fluoro-1- Ethylquinolinium, 4-methyl-1-isopropylquinolinium, and the like, but are not limited thereto.

Onium cation (isoquinolinium cation) corresponding to general formula (9):

Examples of isoquinolinium cation:

N-phenylisoquinolinium, N-methylisoquinolinium, N-ethylisoquinolinium, N-(o-chlorophenyl)isoquinolinium, N-(m-chlorophenyl)isoquinolinium, N-(p-cyanophenyl)isoquinolinium, N-(o-nitrophenyl)isoquinolinium, N-(p-acetylphenyl)isoquinolinium, N-(p-isopropylphenyl)iso Quinolinium, N-(p-octadecyloxyphenyl)isoquinolinium, N-(p-methoxycarbonylphenyl)isoquinolinium, N-(9-anthryl)isoquinolinium, 1, 2-diphenylisoquinolinium, N-(2-furyl)isoquinolinium, N-(2-thienyl)isoquinolinium, N-naphthylisoquinolinium, etc. are mentioned. It is not limited.

Onium cation (benzoxazolium cation, benzothiazolium cation) corresponding to the general formula (10):

Examples of benzoxazolium cation:

N-methylbenzooxazolium, N-ethylbenzooxazolium, N-naphthylbenzooxazolium, N-phenylbenzooxazolium, N-(p-fluorophenyl)benzooxazolium, N-(p-chlorophenyl) Benzooxazolium, N-(p-cyanophenyl)benzoxazolium, N-(o-methoxycarbonylphenyl)benzoxazolium, N-(2-furyl)benzooxazolium, N-(o-fluoro Phenyl) benzoxazolium, N-(p-cyanophenyl) benzoxazolium, N-(m-nitrophenyl) benzoxazolium, N-(p-isopropoxycarbonylphenyl) benzoxazolium, N-( 2-thienyl)benzoxazolium, N-(m-carboxyphenyl)benzoxazolium, 2-mercapto-3-phenylbenzooxazolium, 2-methyl-3-phenylbenzooxazolium, 2-methylthio-3 -(4-phenylsulfanylphenyl)benzoxazolium, 6-hydroxy-3-(p-tolyl)benzooxazolium, 7-mercapto-3-phenylbenzooxazolium, 4,5-difluoro-3 -Ethyl benzoxazolium, etc. are mentioned, but it is not limited to these.

Examples of benzothiazolium cation:

N-methylbenzothiazolium, N-ethylbenzothiazolium, N-phenylbenzothiazolium, N-(1-naphthyl)benzothiazolium, N-(p-fluorophenyl)benzothiazolium, N-(p -Chlorophenyl)benzothiazolium, N-(p-cyanophenyl)benzothiazolium, N-(o-methoxycarbonylphenyl)benzothiazolium, N-(p-tolyl)benzothiazolium, N-( o-fluorophenyl)benzothiazolium, N-(m-nitrophenyl)benzothiazolium, N-(p-isopropoxycarbonylphenyl)benzothiazolium, N-(2-furyl)benzothiazolium, N -(4-methylthiophenyl)benzothiazolium, N-(4-phenylsulfanylphenyl)benzothiazolium, N-(2-naphthyl)benzothiazolium, N-(m-carboxyphenyl)benzothiazolium, 2-mercapto-3-phenylbenzothiazolium, 2-methyl-3-phenylbenzothiazolium, 2-methylthio-3-phenylbenzothiazolium, 6-hydroxy-3-phenylbenzothiazolium, 7-mer Capto-3-phenylbenzothiazolium, 4,5-difluoro-3-phenylbenzothiazolium, etc. may be mentioned, but the present invention is not limited thereto.

Onium cation (furyl or thienyliodonium cation) corresponding to the general formula (11):

Difuryliodonium, dithienyliodonium, bis(4,5-dimethyl-2-furyl)iodonium, bis(5-chloro-2-thienyl)iodonium, bis(5-cyano-2-furyl) ) Iodonium, bis(5-nitro-2-thienyl)iodonium, bis(5-acetyl-2-furyl)iodonium, bis(5-carboxy-2-thienyl)iodonium, bis(5-me Toxycarbonyl-2-furyl)iodonium, bis(5-phenyl-2-furyl)iodonium, bis(5-(p-methoxyphenyl)-2-thienyl)iodonium, bis(5-vinyl- 2-furyl)iodonium, bis(5-ethynyl-2-thienyl)iodonium, bis(5-cyclohexyl-2-furyl)iodonium, bis(5-hydroxy-2-thienyl)iodonium , Bis(5-phenoxy-2-furyl)iodonium, bis(5-mercapto-2-thienyl)iodonium, bis(5-butylthio-2-thienyl)iodonium, bis(5-phenyl Thio-2-thienyl)iodonium, etc. are mentioned, but it is not limited to these.

Onium cation (diaryliodonium cation) corresponding to the general formula (12):

Diphenyliodonium, bis(p-tolyl)iodonium, bis(p-octylphenyl)iodonium, bis(p-octadecylphenyl)iodonium, bis(p-octyloxyphenyl)iodonium, bis(p- Octadecyloxyphenyl) iodonium, phenyl (p-octadecyloxyphenyl) iodonium, 4-isopropyl-4'-methyldiphenyliodonium, (4-isobutylphenyl)-p-tolyliodonium, bis( 1-naphthyl)iodonium, bis(4-phenylsulfanylphenyl)iodonium, phenyl(6-benzoyl-9-ethyl-9H-carbazol-3-yl)iodonium, (7-methoxy-2- Oxo-2H-chromen-3-yl)-4'-isopropylphenyliodonium, and the like, but are not limited thereto.

Next, the counter anion X ^- in General Formula (3) will be described.

The counter anion X ^- in General Formula (3) is not particularly limited in principle, but a non-nucleophilic anion is preferable. When the counter anion X ^- is a non-nucleophilic anion, it is difficult to cause a nucleophilic reaction in a cation coexisting in a molecule or various materials used in combination. As a result, the photoacid generator itself represented by the general formula (2) The stability over time of the composition using it can be improved. The non-nucleophilic anion here refers to an anion having a low ability to cause a nucleophilic reaction. In this anion, such as it is, PF ₆ ^-, and the like _{^{-, SbF 6 -, AsF 6}} -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate anion, SCN .

As particularly preferred as is, PF ₆ ^{- -} counter anion X in from the one illustrated anionic, formula (3), SbF ₆ ^-, and AsF ₆ ^- may be mentioned, and particularly preferably PF ₆ ^-, SbF ₆ ^- is mentioned.

Thus, specific examples of the structure of the Preferred onium salts embodiment constituting the photo-acid generator (H) of the present invention, the onium cation represented by formula (3) to Formula (12) in the illustrated example and PF ₆ ^{- _{, SbF 6 -, AsF 6 -}} , SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 - is an anion selected from the consisting of O salt ^-, dithiocarbamate anion, SCN.

Specifically, "Syracure UVI-6992", "Syracure UVI-6974" (above, manufactured by Dow Chemical Nippon Co., Ltd.), "Adeka Optomer SP150", "Adeka Optomer SP152", "Adeka Optomer SP170", "Adeka Optomer SP172" (above, manufactured by ADEKA Corporation), "IRGACURE 250" (manufactured by Chiba Specialty Chemicals), "CI-5102", "CI-2855" (above, manufactured by Nippon Soda Corporation) ), ``San-Aid SI-60L'', ``San-Aid SI-80L'', ``San-Aid SI-100L'', ``San-Aid SI-110L'', ``San-Aid SI-180L'' (above, manufactured by Sanshin Chemical), `` CPI-100P", "CPI-100A" (above, manufactured by San Apro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", " WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (above, manufactured by Wako Junyaku Corporation) are preferred specific examples of the photoacid generator (H) of the present invention It can be mentioned as.

The content of the photoacid generator (H) is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive. It is particularly preferably in parts by weight.

In the active energy ray-curable adhesive, it is preferable to use a photoacid generator (H) and a compound (I) containing either an alkoxy group or an epoxy group in the active energy ray-curable adhesive.

(Compound and polymer having an epoxy group) (I)

When a compound having one or more epoxy groups in the molecule or a polymer (epoxy resin) having two or more epoxy groups in the molecule is used, a compound having two or more functional groups having reactivity with an epoxy group may be used in combination. Here, the functional group having reactivity with the epoxy group includes, for example, a carboxyl group, a phenolic hydroxyl group, a mercapto group, and a primary or secondary aromatic amino group. It is particularly preferable to have two or more of these functional groups in one molecule in consideration of three-dimensional curability.

Examples of the polymer having one or more epoxy groups in the molecule include epoxy resins, bisphenol A type epoxy resins derived from bisphenol A and epichlorhydrin, bisphenol F derived from bisphenol F and epichlorhydrin. Type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy Resin, hydroquinone type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, polyfunctional type epoxy resin such as trifunctional type epoxy resin or tetrafunctional type epoxy resin, glycidyl ester type epoxy resin , Glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain type epoxy resin, and the like, and these epoxy resins may be halogenated or hydrogenated. Commercially available epoxy resin products include, for example, JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000, manufactured by Japan Epoxy Resin Co., Ltd., Epiclon manufactured by DIC Corporation. 830, EXA835LV, HP4032D, HP820, ADEKA Co., Ltd. EP4100 series, EP4000 series, EPU series, Daicel Chemical Co., Ltd. Celoxide series (2021, 2021P, 2083, 2085, 3000, etc.), Eporide series, EHPE series, YD series, YDF series, YDCN series, YDB series, phenoxy resin (polyhydroxypolyether synthesized from bisphenols and epichlorhydrin, and has epoxy groups at both ends; YP series, etc.) manufactured by Shinnittetsu Chemical Co., Ltd., Nagase The Denacol series manufactured by Chemtex Co., Ltd., and the Epolite series manufactured by Kyoeisha Chemical Co., Ltd. can be exemplified, but are not limited thereto. These epoxy resins may use 2 or more types together. In addition, when calculating the glass transition temperature Tg of the adhesive layer, it is assumed that the compound having an epoxy group and the polymer (H) are not counted.

(Compound and polymer having an alkoxyl group) (I)

The compound having an alkoxyl group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. As such a compound, a melamine compound, an amino resin, etc. are typically mentioned.

The compounding amount of the compound (I) containing either an alkoxy group or an epoxy group is usually 30 parts by weight or less based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive, and the content of the compound (I) in the composition is If it is too large, adhesiveness may fall and impact resistance to a drop test may deteriorate. It is more preferable that the content of the compound (I) in the composition is 20 parts by weight or less. On the other hand, from the viewpoint of water resistance of the cured product layer (adhesive layer (2a)), it is preferable to contain 2 parts by weight or more of the compound (I) in the composition, and more preferably 5 parts by weight or more.

When the active energy ray-curable adhesive related to the low-elastic adhesive layer (a) of the present invention is used as an electron beam-curable type, it is not particularly necessary to contain a photopolymerization initiator in the composition, but when used as an ultraviolet-curable type, a photopolymerization initiator is used. It is preferable to use a photopolymerization initiator that is highly sensitive to light of 380 nm or more. A photopolymerization initiator that is highly sensitive to light of 380 nm or more will be described later.

In the active energy ray-curable adhesive according to the low elastic adhesive layer (a) of the present invention, as a photoinitiator, a compound represented by the general formula (1);

[Formula 13]

(In the formula, R ¹ and R ² represent -H, -CH _2b H ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different), or as a general formula (1) It is preferable to use together the compound shown and a photoinitiator which is highly sensitive to light of 380 nm or more described later. When the compound represented by the general formula (1) is used, it is superior in adhesion compared to the case where a photoinitiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are -CH _2b H ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (1) in the composition is preferably 0.1 to 5.0 parts by weight, and more preferably 0.5 to 4.0 parts by weight based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive. And, it is more preferably 0.9 to 3.0 parts by weight.

Moreover, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiation aid include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and 4-dimethylaminobenzoic acid. Somatomeal and the like, and ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the addition amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, most preferably 0, based on 100 parts by weight of the total amount of the radical polymerizable compound in the active energy ray-curable adhesive. It is-3 parts by weight.

Moreover, a known photopolymerization initiator can be used together as needed. As a photoinitiator, it is preferable to use a photoinitiator which is highly sensitive to light of 380 nm or more. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-buta Non-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(H5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro Ro-3-(1H-pyrrol-1-yl)-phenyl) titanium and the like.

In particular, as a photoinitiator, in addition to the photoinitiator of the general formula (1), a compound further represented by the following general formula (2);

[Formula 14]

(In the formula, R ³ , R ⁴ and R ⁵ represent -H, -CH _3b H _2b H ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different) It is preferable to use Do. As the compound represented by the general formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE 907 manufacturer: BASF), which is also a commercial product, is preferably used. Can be used. In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE 369 manufacturer: BASF), 2-(dimethylamino)-2-[(4- Methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE 379 manufacturer: BASF) is preferable because of its high sensitivity.

Further, in the active energy ray-curable adhesive according to the low-elastic adhesive layer (a) of the present invention, various additives can be blended as other optional components within a range that does not impair the object and effect of the present invention. Examples of such additives include epoxy resin, polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, Polymers or oligomers such as fluorine-based oligomers, silicone-based oligomers, and polysulfide-based oligomers; Polymerization inhibitors such as phenothiazine and 2,6-di-T-butyl-4-methylphenol; Polymerization initiation aid; Leveling agent; Wettability improving agent; Surfactants ; Plasticizer; Ultraviolet absorber; Inorganic filler; Pigment; Dye, etc. are mentioned.

The active energy ray-curable adhesive according to the present invention is cured by irradiating with an active energy ray to form a low elastic adhesive layer (a).

As the active energy ray, one containing an electron beam and a visible ray having a wavelength range of 380 nm to 450 nm can be used. Further, the long wavelength limit of visible light is about 780 nm, but visible light exceeding 450 nm does not contribute to absorption of the polymerization initiator and may cause heat generation. For this reason, in the present invention, it is preferable to use a band pass filter to block visible light on the long wavelength side exceeding 450 nm.

As the electron beam irradiation conditions, any suitable conditions can be adopted as long as the active energy ray-curable adhesive can be cured. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. When the acceleration voltage is less than 5 kV, there is a fear that the electron beam does not reach the adhesive, resulting in insufficient curing, and when the acceleration voltage exceeds 300 kV, the penetrating force passing through the sample is too strong, and the polarizing film (P) and the optical film ( There is a risk of damaging 3). The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive becomes insufficient in curing, and when it exceeds 100 kGy, damage is given to the polarizing film (P) and the optical film (3), causing a decrease in mechanical strength or yellowing, resulting in a predetermined optical property. Can't get

The electron beam irradiation is usually irradiated in an inert gas, but if necessary, it may be carried out in the atmosphere or under the condition of introducing a little oxygen. It depends on the material of the transparent protective film, but by appropriately introducing oxygen, oxygen is deliberately inhibited on the surface of the transparent protective film to which the electron beam first touches, thereby preventing damage to the transparent protective film, and efficiently irradiating electron beams only with the adhesive. I can.

However, in the manufacturing method of the laminated polarizing film according to the present invention, while increasing the adhesion performance of the low elastic adhesive layer (a) between the polarizing film (P) and the optical film (3), to prevent curling of the polarizing film (P). For this purpose, it is preferable to use an active energy ray containing visible light having a wavelength range of 380 nm to 450 nm, and particularly, an active energy ray having the greatest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm. When using the film (ultraviolet non-transmissive film) to which the ultraviolet absorption ability was given to the transparent protective film or optical film 3 of the polarizing film (P), 380 nm absorbed by the transparent protective film or the optical film (3) Light with a shorter wavelength is converted into heat, and the transparent protective film and the optical film 3 generate heat, causing a defect such as curls and wrinkles of the laminated polarizing film. Therefore, in the present invention, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as the active energy ray generating device, and more specifically, the integrated illuminance in the wavelength range 380 to 440 nm and the wavelength range 250 to It is preferable that it is 100:0-100:50, and it is more preferable that it is 100:0-100:40 ratio of the integrated roughness of 370 nm. As an active energy ray that satisfies such a relationship of integrated illuminance, a gallium-encapsulated metal halide lamp and an LED light source emitting light in a wavelength range of 380 to 440 nm are preferable. Alternatively, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an incandescent lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a gallium lamp, an excimer laser or sunlight as a light source, and a band A pass filter may be used to block light with a wavelength shorter than 380 nm. In order to prevent curling of the polarizing film while improving the adhesive performance of the adhesive layer between the polarizing film (P) and the optical film (3), the low-elasticity adhesive layer (a), blocking light of a wavelength shorter than 400 nm It is preferable to use an active energy ray obtained using a possible band pass filter or an active energy ray having a wavelength of 405 nm obtained using an LED light source.

In the visible ray-curable type, it is preferable to warm the active energy ray-curable adhesive before irradiation with visible light (heating before irradiation), and in that case, heating to 40°C or higher is preferable, and heating to 50°C or higher is more preferable. desirable. In addition, heating the active energy ray-curable adhesive after irradiation with visible light (heating after irradiation) is also preferable. In that case, heating to 40°C or higher is preferable, and heating to 50°C or higher is more preferable.

The active energy ray-curable adhesive related to the low-elastic adhesive layer (a) contains the photopolymerization initiator of the general formula (1) described above, so that ultraviolet rays are irradiated over the optical film 3 having UV-absorbing ability, and the low-elastic adhesive layer ( a) can be formed to harden. As the optical film 3, what has a light transmittance of less than 5% at a wavelength of 365 nm can be used.

As a method of imparting UV absorbing ability to the optical film 3, a method of including an ultraviolet absorber in the optical film 3, or a method of laminating a surface treatment layer containing an ultraviolet absorber on the surface of the optical film 3 is mentioned. .

Specific examples of the ultraviolet absorber include, for example, conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, and triazine compounds. And the like.

The manufacturing method of the laminated polarizing film according to the present invention,

On at least one surface of the transparent protective film (2) and the optical film (3) on the side on which the low-elastic adhesive layer (a) in the polarizing film (P) is laminated, the low-elastic adhesive layer (a) A coating step of applying an active energy ray-curable adhesive to form a,

A bonding step of bonding the polarizing film (P) and the optical film (3) together,

It includes an adhesion step of adhering the polarizing film (P) and the optical film (3) through the low elastic adhesive layer (a) obtained by irradiating the active energy ray and curing the active energy ray-curable adhesive.

The transparent protective film (2) and the optical film (3) in the polarizing film (P) may be subjected to a surface modification treatment before coating the active energy ray-curable adhesive. Specific treatments include corona treatment, plasma treatment, saponification treatment, excimer treatment, or frame treatment.

The coating method of the active energy ray-curable adhesive is appropriately selected depending on the viscosity of the composition and the desired thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or offset), a varverse coater, a roll coater, a die coater, a bar coater, a rod coater, and the like. In addition, a method such as a dipping method can be appropriately used for coating.

The polarizing film (P) and the optical film (3) are bonded through the adhesive applied as described above. The bonding of the polarizing film (P) and the optical film 3 can be performed by a roll laminator or the like.

After bonding the polarizing film (P) and the optical film (3), an active energy ray (electron ray, ultraviolet ray, visible ray, etc.) is irradiated to cure the active energy ray-curable adhesive to form a low elastic adhesive layer (a). The irradiation direction of active energy rays (electron rays, ultraviolet rays, visible rays, etc.) can be irradiated from any suitable direction. Preferably, it irradiates from the optical film (3) side. When irradiated from the polarizing film (P) side, the polarizing film (P) may be deteriorated by active energy rays (electron rays, ultraviolet rays, visible rays, etc.).

In the case of producing the laminated polarizing film according to the present invention in a continuous line, the line speed varies depending on the curing time of the adhesive, but is preferably 1 to 500 m/min, more preferably 5 to 300 m/min, more preferably It is preferably 10 to 100 m/min. When the line speed is too small, productivity is insufficient, or damage to the polarizing film (P) and the optical film (3) is excessively large, and a polarizing film that can withstand a durability test or the like cannot be produced. When the line speed is too large, the curing of the adhesive becomes insufficient, and the target adhesiveness may not be obtained.

<polarizing film>

As described above, as for the polarizing film P, the transparent protective film 2 is formed on at least one surface of the polarizer 1 through the adhesive layer (b).

<polarizer>

The polarizer 1 is not particularly limited, and various things can be used. As a polarizer, dichroic materials such as iodine and dichroic dyes are adsorbed to hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene/vinyl acetate copolymer-based partial saponification films. Polyene-based oriented films, such as the thing which was made and uniaxially stretched, the dehydration-processed product of polyvinyl alcohol, and the dehydrochloric acid-treated product of polyvinyl chloride, etc. are mentioned. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

A polarizer obtained by uniaxially stretching a polyvinyl alcohol-based film by dyeing it with iodine can be produced by, for example, dyeing by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution such as boric acid or potassium iodide. Further, if necessary, before dyeing, the polyvinyl alcohol-based film may be immersed in water and washed with water. By washing the polyvinyl alcohol-based film with water, it is possible to wash the surface of the polyvinyl alcohol-based film with an anti-contamination or blocking agent, and by swelling the polyvinyl alcohol-based film, there is an effect of preventing non-uniformity such as non-uniformity in dyeing. Stretching may be performed after dyeing with iodine, may be stretched while dyeing, or may be dyed with iodine after stretching. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, as a polarizer, a thin polarizer having a thickness of 10 μm or less can be used. Speaking from the viewpoint of thinning, the thickness is preferably 1 to 7 µm. It is preferable that such a thin polarizer has little thickness unevenness, is excellent in visibility, and has little dimensional change, so it is excellent in durability, and furthermore, the thickness as a polarizing film is also reduced in thickness. Moreover, since the water content of a thin polarizer is easily lowered during heating and drying, it can be preferably used as a polarizer having a water content of 15% or less.

As a thin polarizer, representatively, Japanese Patent Application Laid-Open No. 51-069644 or Japanese Patent Application Laid-Open No. 2000-338329, a pamphlet of WO2010/100917, a specification of PCT/JP2010/001460, or a specification of Japanese Patent Application No. 2010-269002 or The thin polarizing film described in the specification of Japanese Patent Application No. 2010-263692 is mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a resin substrate for stretching in the state of a laminate and a step of dyeing. According to this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as fracture due to stretching by being supported by the resin substrate for stretching.

As the thin polarizing film, among the manufacturing methods including the step of stretching and dyeing in the state of a laminate, since it can be stretched at a high magnification to improve polarization performance, WO2010/100917 pamphlet, PCT/JP2010/ It is preferable that it is obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution described in the specification of 001460 or the specification of Japanese Patent Application 2010-269002 or the specification of Japanese Patent Application 2010-269002, and in particular, Japanese Patent Application 2010-269002 It is preferably obtained by a manufacturing method including a step of auxiliary air stretching before stretching in an aqueous boric acid solution described in the specification or Japanese Patent Application No. 2010-263692.

The thin high-performance polarizing film described in the specification of PCT/JP2010/001460 is a thin high-functional polarizing film having a thickness of 7 μm or less made of a PVA-based resin in which a dichroic substance is oriented, which is integrally formed on a resin substrate, and has a single transmittance of 42.0%. It has an optical property of 99.95% or more of ideal and polarization degree.

The thin high-function polarizing film is formed by applying and drying a PVA-based resin on a resin substrate having a thickness of at least 20 µm to generate a PVA-based resin layer, and immersing the resulting PVA-based resin layer in a dyeing solution of a dichroic material A PVA-based resin layer with a dichroic material adsorbed on the PVA-based resin layer, and a PVA-based resin layer with a dichroic material adsorbed thereon, in a boric acid aqueous solution, can be prepared by stretching the total draw ratio to be 5 times or more of the original length integrally with the resin substrate. I can.

In addition, as a method of manufacturing a laminate film comprising a thin high-performance polarizing film in which a dichroic substance is oriented, a resin substrate having a thickness of at least 20 µm and an aqueous solution containing a PVA-based resin are applied and dried on one side of the resin substrate. The process of producing a laminate film including a PVA-based resin layer formed by doing so, and the laminate film including a resin substrate and a PVA-based resin layer formed on one side of the resin substrate are immersed in a dye solution containing a dichroic substance. By doing so, the process of adsorbing a dichroic substance to the PVA-based resin layer included in the laminate film, and the laminate film including the PVA-based resin layer adsorbed with the dichroic substance, in a boric acid aqueous solution, the total draw ratio is A PVA-based resin layer in which a dichroic substance is oriented on one side of the resin substrate by stretching the original length to be 5 or more times and the PVA-based resin layer adsorbing the dichroic substance is stretched integrally with the resin substrate. The thin high-performance polarizing film can be produced by including the step of producing a laminate film formed by forming a thin high-function polarizing film having optical properties having a thickness of 7 μm or less, a single transmittance of 42.0% or more and a polarization degree of 99.95% or more have.

The Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692 The thin polarizing film is a polarizing film of a continuous web made of PVA-based resin in which a dichroic substance is oriented, and is formed on an amorphous ester-based thermoplastic resin substrate. The layered product including the PVA-based resin layer was stretched in a two-stage stretching step consisting of air-assisted stretching and boric acid underwater stretching, thereby obtaining a thickness of 10 μm or less. In such a thin polarizing film, when the single transmittance is T and the polarization degree is P, P> -(100.929T-42.4-1) × 100 (however, T <42.3), and P ≥ 99.9 (however, T ≥ 42.3) It is desirable to have optical properties that satisfy the conditions.

Specifically, the thin polarizing film comprises a step of producing a stretched intermediate product comprising an oriented PVA-based resin layer by aerial high-temperature stretching of a PVA-based resin layer formed on an amorphous ester-based thermoplastic resin substrate of a continuous web, and , A process of producing a colored intermediate product comprising a PVA-based resin layer in which a dichroic material (iodine or a mixture of iodine and an organic dye is preferred) is oriented by adsorption of the dichroic material to the stretched intermediate product, and the coloring intermediate It can be produced by a method for producing a thin polarizing film including a step of producing a polarizing film having a thickness of 10 μm or less comprising a PVA-based resin layer in which a dichroic substance is oriented by stretching the product in water with boric acid.

In this production method, it is preferable that the total draw ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate by aerial high-temperature stretching and boric acid-in-water stretching is 5 times or more. The liquid temperature of the aqueous boric acid solution for stretching boric acid in water can be 60°C or higher. Before stretching the colored intermediate product in an aqueous boric acid solution, it is preferable to perform an insolubilization treatment on the colored intermediate product, and in that case, it is preferable to immerse the colored intermediate product in an aqueous boric acid solution whose liquid temperature does not exceed 40°C. Do. The amorphous ester-based thermoplastic resin substrate may be an amorphous polyethylene terephthalate comprising a copolymerized polyethylene terephthalate copolymerized with isophthalic acid, a copolymerized polyethylene terephthalate copolymerized with cyclohexanedimethanol, or another copolymerized polyethylene terephthalate, It is preferably made of a transparent resin, and its thickness can be made 7 times or more of the thickness of the PVA-based resin layer to be formed. Moreover, the draw ratio of the aerial high-temperature stretching is preferably 3.5 times or less, and the stretching temperature of the aerial high-temperature stretching is preferably not less than the glass transition temperature of the PVA-based resin, and specifically in the range of 95°C to 150°C. In the case of performing aerial high-temperature stretching by uniaxial stretching at the free end, the total draw ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more and 7.5 times or less. Moreover, when performing aerial high temperature stretching by fixed stage uniaxial stretching, it is preferable that the total draw ratio of the PVA-type resin layer formed into a film on the amorphous ester-type thermoplastic resin base material is 5 times or more and 8.5 times or less.

More specifically, a thin polarizing film can be manufactured by the following method.

A base material of a continuous web of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) obtained by copolymerizing 6 mol% of isophthalic acid was prepared. The glass transition temperature of amorphous PET is 75°C. A laminate comprising a continuous web of amorphous PET substrate and a polyvinyl alcohol (PVA) layer was prepared as follows. Moreover, the glass transition temperature of PVA is 80 degreeC.

A PVA aqueous solution having a concentration of 4 to 5% in which an amorphous PET substrate having a thickness of 200 µm and a PVA powder having a polymerization degree of 1000 or more and a saponification degree of 99% or more is dissolved in water is prepared. Next, a PVA aqueous solution was applied to a 200 µm-thick amorphous PET substrate and dried at a temperature of 50 to 60°C to obtain a laminate in which a 7 µm-thick PVA layer was formed on the amorphous PET substrate.

A laminate comprising a 7 µm-thick PVA layer is subjected to the following steps including a two-stage stretching step of air-assisted stretching and boric acid underwater stretching, to produce a thin, high-performance polarizing film having a thickness of 3 µm. A laminate comprising a PVA layer having a thickness of 7 µm is stretched integrally with an amorphous PET substrate by the air-assisted stretching step of the first step to produce a stretched laminate comprising a PVA layer having a thickness of 5 µm. Specifically, in this stretched laminate, a laminate comprising a 7 µm-thick PVA layer was hung on a stretching device disposed in an oven set in a stretching temperature environment of 130°C, and the stretch ratio was increased to 1.8 times with one free end axis. It is stretched. By this stretching treatment, the PVA layer contained in the stretched laminate is changed into a 5 µm-thick PVA layer in which PVA molecules are oriented.

Next, a colored laminate in which iodine is adsorbed onto a 5 μm-thick PVA layer in which PVA molecules are oriented is produced by a dyeing process. Specifically, in this colored laminate, the stretched laminate was placed in a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30° C. so that the single transmittance of the PVA layer constituting the finally produced high-functional polarizing film was 40 to 44%. By immersion for an arbitrary time, iodine was adsorbed to the PVA layer contained in the stretched laminate. In this step, the dyeing solution uses water as a solvent, the iodine concentration is in the range of 0.12 to 0.30% by weight, and the potassium iodide concentration is in the range of 0.7 to 2.1% by weight. The ratio of concentrations of iodine and potassium iodide is 1 to 7. In addition, potassium iodide is required to dissolve iodine in water. More specifically, by immersing the stretched laminate for 60 seconds in a dye solution having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight, a colored laminate in which iodine is adsorbed on a 5 μm-thick PVA layer in which PVA molecules are oriented was prepared. Generate.

In addition, the colored laminate is further stretched integrally with the amorphous PET substrate by the second step of the boric acid underwater stretching process, thereby producing an optical film laminate comprising a PVA layer constituting a high-functional polarizing film having a thickness of 3 μm. . Specifically, this optical film layered product is free to attach the colored layered product to a stretching device disposed in a treatment device set with an aqueous boric acid solution in a liquid temperature range of 60 to 85°C containing boric acid and potassium iodide, and the draw ratio is 3.3 times. It is stretched with only one axis. More specifically, the solution temperature of the aqueous boric acid solution is 65°C. In addition, the boric acid content is 4 parts by weight based on 100 parts by weight of water, and the potassium iodide content is 5 parts by weight based on 100 parts by weight of water. In this step, the colored layered product in which the amount of iodine adsorption was adjusted is first immersed in an aqueous boric acid solution for 5 to 10 seconds. After that, the colored layered product is passed through a plurality of sets of rolls having different circumferential speeds, which are stretching devices arranged in the processing device as it is, and stretched with one free end so that the draw ratio is 3.3 times over 30 to 90 seconds. do. By this stretching treatment, the PVA layer contained in the colored layered product is changed into a 3 µm-thick PVA layer in which the adsorbed iodine is oriented at a high degree in one direction as a polyiodine ion complex. This PVA layer constitutes a highly functional polarizing film of an optical film laminate.

Although it is not an essential step for the manufacture of the optical film laminate, the optical film laminate is taken out from the aqueous boric acid solution by the cleaning process, and the boric acid adhering to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate is added to the aqueous potassium iodide solution. It is preferable to wash with. After that, the washed optical film layered product is dried by a drying step with a warm air at 60°C. In addition, the washing step is a step for eliminating appearance defects such as precipitation of boric acid.

Similarly, although it is not an essential process for the production of an optical film laminate, an 80 μm-thick triacetylcellulose is applied by applying an adhesive to the surface of the 3 μm-thick PVA layer formed on an amorphous PET substrate by a bonding and/or transfer process. After bonding the films, the amorphous PET substrate may be peeled off, and the 3 µm-thick PVA layer may be transferred to an 80 µm-thick triacetylcellulose film.

[Other processes]

The manufacturing method of the thin polarizing film may include other processes in addition to the above processes. As other processes, an insolubilization process, a crosslinking process, a drying (control of a moisture content) process, etc. are mentioned, for example. Other steps can be performed at any appropriate timing.

The insolubilization step is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing the insolubilization treatment. The concentration of the aqueous boric acid solution is preferably 1 to 4 parts by weight based on 100 parts by weight of water. The liquid temperature of the insolubilization bath (boric acid aqueous solution) is preferably from 20°C to 50°C. Preferably, the insolubilization process is performed after the production of the laminated body and before the dyeing process or the underwater stretching process.

The crosslinking step is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing crosslinking treatment. The concentration of the aqueous boric acid solution is preferably 1 to 4 parts by weight based on 100 parts by weight of water. Moreover, when performing a crosslinking process after the said dyeing process, it is preferable to mix|blend an iodide further. By blending iodide, elution of iodine adsorbed to the PVA-based resin layer can be suppressed. The blending amount of iodide is preferably 1 to 5 parts by weight based on 100 parts by weight of water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably from 20°C to 50°C. Preferably, the crosslinking step is performed before the second boric acid underwater stretching step. In a preferred embodiment, the dyeing step, the crosslinking step, and the second boric acid-in-water stretching step are performed in this order.

<Transparent protective film>

As a material constituting the transparent protective film 2, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, and the like is used. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and (meth)acrylic. Resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. One or more types of arbitrary suitable additives may be contained in the transparent protective film. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% by weight. . When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, there is a fear that the high transparency inherent in the thermoplastic resin cannot be sufficiently expressed.

Moreover, as a material for forming the transparent protective film 2, those excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, etc. are preferable, and in particular, a moisture permeability of 150 g/m 2 /24 h or less is more preferable, It is particularly preferably 140 g/m 2 /24 h or less, and more preferably 120 g/m 2 /24 h or less. The moisture permeability is determined by the method described in Examples.

In the above-described polarizing film, when a transparent protective film having a moisture permeability of 150 g/m 2 /24 h or less is used, moisture in air is difficult to enter into the polarizing film, and a change in moisture content of the polarizing film itself can be suppressed. As a result, curling and dimensional change of the polarizing film caused by the storage environment can be suppressed.

Functional layers, such as a hard coat layer, an antireflection layer, an anti-sticking layer, and a diffusion layer or an anti-glare layer, can be formed on the surface of the transparent protective film 2 on which the polarizer 1 is not adhered. In addition, functional layers such as the hard coat layer, anti-reflection layer, anti-sticking layer, diffusion layer or anti-glare layer can be formed on the transparent protective film 2 itself, and separately from the transparent protective film 2 It can also be formed as one of.

The thickness of the transparent protective film 2 can be appropriately determined, but generally it is about 1 to 500 µm, preferably 1 to 300 µm, and is preferably 5 to 500 µm in terms of workability such as strength and handling properties, and thin layer properties. 200 µm is more preferable. Furthermore, 10 to 200 µm is preferable, and 20 to 80 µm is preferable.

In addition, for the transparent protective film 2 formed on both sides of the polarizer 1, a transparent protective film made of the same polymer material may be used for the front and back, or a transparent protective film made of a different polymer material or the like may be used.

As the transparent protective film, a retardation film having a front retardation of 40 nm or more and/or a retardation in the thickness direction of 80 nm or more may be used. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. When using a retardation film as a transparent protective film, since the said retardation film also functions as a transparent protective film, thickness reduction can be aimed at.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a film supporting an alignment layer of a liquid crystal polymer. The thickness of the retardation film is also not particularly limited, but is generally about 20 to 150 µm.

In addition, in the laminated polarizing film shown in FIGS. 1A and B and FIGS. 2 to 4, a retardation film can be used as the transparent protective film 2. Moreover, the transparent protective film 2 on both sides of the polarizer 1 can also be made into a retardation film on one side or both sides. In particular, in FIGS. 3 and 4, it is preferable to use a retardation film as the transparent protective film on the side of the adhesive layer (b2). In particular, when using a retardation film as the transparent protective film 2 on both sides, the aspect of FIG. 4 is preferable.

<Adhesive layer (b)>

The adhesive layer (b) is not particularly limited as long as it is optically transparent, and various types of water-based, solvent-based, hot-melt-based, and active energy ray-curable ones are used. As described above, the adhesive layer (b) preferably has a predetermined thickness and satisfies a predetermined storage modulus.

Examples of the aqueous curable adhesive include vinyl polymer, gelatin, vinyl latex, polyurethane, isocyanate, polyester, and epoxy. The adhesive layer made of such a water-based adhesive can be formed as a coating dry layer or the like of an aqueous solution, but when the aqueous solution is prepared, a crosslinking agent, other additives, and a catalyst such as an acid may be mixed as necessary.

As the water-based curable adhesive, it is preferable to use an adhesive or the like containing a vinyl polymer, and as the vinyl polymer, a polyvinyl alcohol-based resin is preferable. Further, as the polyvinyl alcohol-based resin, an adhesive containing a polyvinyl alcohol-based resin having an acetoacetyl group is more preferable in terms of improving durability. Moreover, as a crosslinking agent which can be blended into the polyvinyl alcohol-based resin, a compound having at least two functional groups reactive with the polyvinyl alcohol-based resin can be preferably used. For example, boric acid, borax, carboxylic acid compounds, and alkyldiamines; Isocyanates; Epoxys; Monoaldehydes; Dialdehydes; Amino-formaldehyde resin; Further, a divalent metal or a salt of a trivalent metal and an oxide thereof may be mentioned. A water-soluble silicate can be blended into the polyvinyl alcohol-based resin. Lithium silicate, sodium silicate, potassium silicate, etc. are mentioned as a water-soluble silicate.

Moreover, various types of adhesives are used as the active energy ray-curable adhesive, and active energy ray-curable adhesives such as electron beam curing type and ultraviolet curing type can be exemplified. As ultraviolet curable adhesives, radical polymerization curable adhesives and cationic polymerization adhesives can be broadly classified. In addition, a radical polymerization curable adhesive can be used as a heat curable adhesive. As the active energy ray-curable adhesive used for forming the adhesive layer (b), an active energy ray-curable adhesive used for forming the low-elastic adhesive layer (a) can be used.

Among the adhesive layers (b), the adhesive layer (b1) is preferably a polyvinyl alcohol-based adhesive. Moreover, as for the adhesive layer (b2), an active energy ray-curable adhesive is preferable.

The adhesive for forming the low elasticity adhesive layer (a) or the adhesive layer (b) may contain an additive as appropriate if necessary. Examples of additives include coupling agents such as a silane coupling agent and a titanium coupling agent, an adhesion promoter typified by ethylene oxide, an additive that improves wettability with a transparent film, an acryloxy group compound or a hydrocarbon type (natural, synthetic resin), etc. Representative additives that improve mechanical strength and processability, UV absorbers, anti-aging agents, dyes, processing aids, ion trapping agents, antioxidants, tackifiers, fillers (other than metal compound fillers), plasticizers, leveling agents, foam inhibitors , Stabilizers such as an antistatic agent, a heat-resistant stabilizer, and a hydrolysis-resistant stabilizer.

In the laminated polarizing film of the present invention, the polarizing film (P) and the optical film (3) are bonded through the low-elastic adhesive layer (a), but are bonded to the transparent protective film (2) and/or the optical film (3). An easy layer can be formed. Moreover, in the polarizing film (P), the easily bonding layer can be formed in the polarizer (1) and/or the transparent protective film (2).

The easily bonding layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone system, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to the formation of the easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat-resistant stabilizer may be used. The thickness of the easily bonding layer after drying is preferably 0.01 to 5 µm, more preferably 0.02 to 2 µm, and still more preferably 0.05 to 1 µm. In addition, although a plurality of layers of the easily bonding layer can be formed, it is preferable that the total thickness of the easily bonding layer be within the above range even in this case.

<optical film>

As the optical film 3, other than the polarizer 1, for example, a retardation film (including a wavelength plate such as 1/2 or 1/4), a visual compensation film, a brightness enhancing film, a reflecting plate or a semi-transmissive plate What becomes an optical layer which may be used for formation of a liquid crystal display device, etc. can be illustrated. Two or more layers can be used for the said optical film (3). In the case of using two or more layers of optical films, the low-elastic adhesive layer (a) can also be used for lamination of the second optical film. As the optical film (3), a retardation film is preferable.

As the above-described retardation film, one having a retardation of 40 nm or more and/or 80 nm or more of a front retardation similar to the above and/or a thickness direction retardation may be used. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a film supporting an alignment layer of a liquid crystal polymer. The thickness of the retardation film is also not particularly limited, but is generally about 20 to 150 µm.

In the laminated polarizing film of the present invention, a pressure-sensitive adhesive layer for bonding to other members such as a liquid crystal cell can also be formed. The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyether, a fluorine-based or rubber-based polymer may be appropriately selected and used as a base polymer. . In particular, those having excellent optical transparency, suitable wettability, cohesiveness and adhesive properties, such as excellent weather resistance and heat resistance, can be preferably used like acrylic pressure-sensitive adhesives.

The pressure-sensitive adhesive layer may be formed on one side or both sides of a laminated polarizing film or a laminated optical film as a superposed layer of different compositions or types. Moreover, in the case of forming on both sides, it is also possible to use pressure-sensitive adhesive layers such as different compositions, types, and thicknesses on the front and back of a laminated polarizing film or a laminated optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, etc., and is generally 1 to 500 µm, preferably 1 to 200 µm, and particularly preferably 1 to 100 µm.

With respect to the exposed surface of the pressure-sensitive adhesive layer, a separator is temporarily attached for the purpose of preventing contamination and the like while providing it to practical use to form a cover. Thereby, it is possible to prevent contact with the pressure-sensitive adhesive layer in the usual handling state. As the separator, except for the above-described thickness conditions, for example, suitable thin-leaf bodies such as plastic films, rubber sheets, paper, cloth, nonwoven fabrics, nets, foam sheets and metal foils, and laminates thereof may be used as necessary, such as silicone or long chains. An appropriate conventional one, such as an alkyl-based, fluorine-based, or molybdenum sulfide, suitably coated with a release agent, can be used.

The laminated polarizing film or laminated optical film of the present invention can be preferably used for formation of various devices such as a liquid crystal display device. Formation of a liquid crystal display device can be performed according to the conventional method. That is, in general, a liquid crystal display device is formed by properly assembling a liquid crystal cell, a laminated polarizing film or a laminated optical film, and constituent parts such as a lighting system as necessary to attach a driving circuit, etc., but in the present invention There is no limitation in particular except for using the laminated polarizing film or the laminated optical film by, and it may follow conventionally. As for the liquid crystal cell, for example, any type such as TN type, STN type, or π type can be used.

An appropriate liquid crystal display device such as a liquid crystal display device in which a laminated polarizing film or a laminated optical film is disposed on one or both sides of a liquid crystal cell, or a backlight or a reflector in an illumination system can be formed. In that case, the laminated polarizing film or laminated optical film according to the present invention can be provided on one side or both sides of the liquid crystal cell. When a laminated polarizing film or a laminated optical film is provided on both sides, they may be the same or different. In addition, when forming a liquid crystal display, for example, a diffusion plate, an anti-glare layer, an anti-reflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. It can be placed above.

Example

Hereinafter, examples of the present invention will be described, but embodiments of the present invention are not limited thereto.

<Measurement of storage modulus>

For the adhesive layer or pressure-sensitive adhesive layer used in Examples and Comparative Examples, the storage modulus was determined by the following method.

[Measurement method of storage modulus]

The storage modulus was carried out using a viscoelastic spectrometer (trade name: RSA-II) manufactured by Rheometric Corporation. Measurement conditions were the values at 25°C and 85°C in the range of -50°C to 200°C at a frequency of 1 Hz, a sample thickness of 2 mm, a compression weight of 100 g, and a heating rate of 5°C/min. .

<Moisture permeability of transparent protective film>

The measurement of moisture permeability was measured according to the moisture permeability test (cup method) of JIS Z0208. A sample cut into a diameter of 60 mm was set in a moisture-permeable cup containing about 15 g of calcium chloride, and a temperature of 40°C and a humidity of 90% R.H. The moisture permeability (g/m 2 /24 h) was calculated|required by measuring the weight increase of calcium chloride before and after put into the thermostat of and left for 24 hours.

<Transparent protective film>

Transparent protective film (2a): A (meth)acrylic resin having a lactone ring structure having a thickness of 50 µm (moisture permeability 96 g/m 2 /24 h) was subjected to corona treatment and used.

Transparent protective film (2b): A 18-micrometer-thick cyclic polyolefin film (made by Nippon Xeon Corporation: ZEONOR) was subjected to corona treatment and used.

<Polyvinyl alcohol adhesive>

About 100 parts of PVA-based resin containing acetoacetyl (AA) group (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of modification of AA group: 5 mol%, (represented by AA-modified PVA in Table 1)), 20 parts of methylolmelamine was dissolved in pure water under a temperature condition of 30°C to prepare an aqueous solution adjusted to a solid content concentration of 0.5%. This was used as an adhesive, and was used under a temperature condition of 30°C.

<Production of conventional polarizer>

A polyvinyl alcohol film having an average degree of polymerization of 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 µm was immersed in hot water at 30° C. for 60 seconds to swell. Then, it extended|stretched to 3.5 times, dyeing for 1 minute in a 30 degreeC iodine solution of 0.3 weight% (weight ratio: iodine/potassium iodide = 0.5/8). Thereafter, the total draw ratio was stretched to 6 times while being immersed in a 65°C 4% by weight boric acid aqueous solution for 0.5 minutes. After extending|stretching, it dried for 3 minutes in a 70 degreeC oven, and the 26 micrometers-thick polarizer was obtained.

<Production of polarizing film (P1) described in FIG. 2>

After bonding the transparent protective films (2a) and (2b) to both surfaces of the polarizer while applying the polyvinyl alcohol-based adhesive, it was dried at 50° C. for 5 minutes to prepare a polarizing film. The thickness of the adhesive layer (b1) formed on the transparent protective films (2a) and (2b) was both 0.1 µm, the storage modulus at 25°C was 1.5×10 ⁹ Pa, and the storage elastic modulus at 85°C was 1.0×10 ^It was ⁸ Pa.

<Production of thin polarizer>

In order to produce a thin polarizing film, first, a laminate in which a 9 μm-thick PVA layer was formed on an amorphous PET substrate was formed by air-assisted stretching at a stretching temperature of 130°C to produce a stretched laminate, and then the stretched laminate was subjected to dyeing. Optical comprising a 4 µm-thick PVA layer integrally stretched with an amorphous PET substrate so that the colored laminate was stretched in water with boric acid at a stretching temperature of 65°C so that the total draw ratio was 5.94 times. A film laminate was produced. By such two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate are oriented at a high degree, and the iodine adsorbed by dyeing is a polyiodine ion complex, constituting a highly functional polarizing film with a high order in one direction. An optical film laminate comprising a 5 µm PVA layer could be produced.

<Production of the polarizing film (P2) described in FIG. 3>

After bonding the transparent protective film (2a) to the surface of the polarizing film of the optical film laminate while applying the polyvinyl alcohol-based adhesive, drying was performed at 50°C for 5 minutes. The thickness of the adhesive layer (b1) formed on the transparent protective film 2a was 1 µm, the storage modulus at 25°C was 1.5×10 ⁹ Pa, and the storage elastic modulus at 85°C was 1.0×10 ⁸ Pa.

Subsequently, the amorphous PET substrate was peeled off, and an activated energy ray-curable adhesive shown below (same as the active energy ray-curable adhesive related to the low-elastic adhesive layer (a) of Example 1 below) was applied to the peeling surface. And, after bonding the said transparent protective film 2b, it cured with ultraviolet-ray, and the polarizing film using the thin polarizing film was produced. The thickness of the adhesive layer (b2) formed on the transparent protective film 2b was 5 µm, the storage elastic modulus at 25°C was 8.0×10 ⁶ Pa, and the storage elastic modulus at 85°C was 8.0×10 ⁶ Pa.

<Active energy ray>

Ultraviolet (gallium-enclosed metal halide lamp) irradiation device as an active energy ray: Fusion UV Systems, Inc. Light HAMMER10 valve: V valve peak illuminance: 1600 mW/㎠, accumulated irradiation dose 1000/mJ/㎠ (wavelength 380 to 440 nm) Was used. In addition, the irradiance of ultraviolet rays was measured using the Sola-Check system manufactured by Solatell.

<Measurement of viscosity>

The viscosity (cp/25°C) of the active energy ray-curable adhesive or pressure-sensitive adhesive used in Examples and Comparative Examples is a value measured by an E-type rotary viscometer. The measurement results are shown in Table 1.

Examples 1 to 4 and Comparative Example 1

(Adjustment of active energy ray-curable adhesive related to low elastic adhesive layer (a))

According to the formulation table shown in Table 1, each component was mixed and stirred at 50° C. for 1 hour to obtain an active energy ray-curable adhesive. The numerical value of the active energy ray-curable adhesive in the table represents parts by weight.

(Phase difference film)

An acrylic retardation film (Atone manufactured by JSR, 40 mu m thickness, front retardation 140 nm) was used.

(The manufacturing method of a laminated polarizing film)

On the corona surface of the retardation film, an active energy ray-curable adhesive related to the low-elastic adhesive layer (a) shown in Table 1 was applied to an MCD coater (manufactured by Fuji Machinery) (cell shape: honeycomb, gravure roll player: 1000 pieces/INCH, It applied so that it might become the thickness shown in Table 1 using rotation speed 140%/line speed comparison).

The adhesive coated surface of the retardation film was bonded to the polarizing film (P1) or (P2). In the polarizing film (P1), it adhered to the side of the transparent protective film (2b), and in the polarizing film (P2) to the side of the transparent protective film (2a). Thereafter, from the side of the bonded retardation film, it was heated to 50° C. using an IR heater, irradiated with the above ultraviolet rays to cure the active energy ray-curable adhesive related to the low elastic adhesive layer (a), and then at 70° C. for 3 minutes. It dried with hot air and obtained the laminated polarizing film. The line speed of bonding was performed at 15 m/min.

Comparative Examples 2 and 3

<Preparation of (meth)acrylic polymer>

In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet pipe, and cooler, 92 parts of butyl acrylate, 5 parts of N-acryloylmorpholine, 2.9 parts of acrylic acid, 0.1 part of 2-hydroxylethyl acrylate, polymerization 0.1 parts by weight of 2,2'-azobisisobutyronitrile and 200 parts by weight of ethyl acetate were injected as initiators, and nitrogen gas was introduced to replace nitrogen with gentle stirring, and then the liquid temperature in the flask was maintained at around 55°C. Time polymerization reaction was performed, and an acrylic polymer solution was prepared. The weight average molecular weight of the acrylic polymer was 2.2 million.

<Production of a polarizing film with an adhesive layer>

To 100 parts of the solid content of the acrylic polymer solution obtained above, 0.2 parts of a polyisocyanate crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Industrial Co., Ltd.) consisting of a trimethylolpropane adduct of tolylene diisocyanate as a crosslinking agent was added to prepare an acrylic pressure-sensitive adhesive solution. I did. Next, the acrylic pressure-sensitive adhesive solution was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film, thickness: 38 μm), and the thickness of the pressure-sensitive adhesive layer after drying was shown in Table 1. It applied (5.5 µm in Comparative Example 2; 4.0 µm in Comparative Example 3) and dried at 150°C for 3 minutes to form a pressure-sensitive adhesive layer.

<Production of laminated polarizing film>

The pressure-sensitive adhesive layer was bonded to the polarizing film (P1) or (P2). In the polarizing film (P1), the adhesive layer was pasted on the side of the transparent protective film 2b, and in the polarizing film (P2) on the side of the transparent protective film 2a. Then, the PET film was peeled, the retardation film was bonded together to obtain a laminated polarizing film.

The following evaluation was performed about the laminated polarizing film obtained in each example. Table 1 shows the results.

<Impact resistance>

The pressure-sensitive adhesive layer was laminated on the retardation film surface of the laminated polarizing film, and cut into a rectangle of 50 mm in the stretching direction of the polarizer and 100 mm in the vertical direction. A sample was prepared by laminating the laminated polarizing film on a glass plate having a thickness of 0.5 mm, a length of 120 mm, and a width of 60 mm. Further, on the back surface of the glass plate, cellophane tape was attached to the entire surface to prevent destruction.

The produced sample was naturally dropped from 1 m in height. After repeating the dropping 100 times, the state of peeling of the end portion was observed visually.

○: Peeling was not confirmed.

?: Peeling from the end is less than 1 mm.

X: 1 mm or more of peeling off from the end.

<Heating buckling property>

The pressure-sensitive adhesive layer was laminated on the retardation film surface of the laminated polarizing film, and cut into a rectangle of 200 mm in the stretching direction of the polarizer and 400 mm in the vertical direction. On both sides of a liquid crystal cell (a liquid crystal cell was taken out and used from "32-inch liquid crystal television BRAVIA (registered trademark) KDL-32F1 manufactured by Sony Corporation"), the laminated polarizing film was laminated so as to be in a cross-Nichol state through the pressure-sensitive adhesive layer, The panel was produced. The following test was performed about this liquid crystal panel.

1: Heating test (12 hours each at 85°C)

2: -40 degreeC ⇔ 85 degreeC heat cycle test is performed, and 100 cycles

After the test, the liquid crystal panel was visually observed, and the stripe non-uniformity was evaluated based on the following criteria.

○: The occurrence of uneven streaks is not observed.

X: Stripe unevenness occurred.

<Peeling force: Forced peeling>

The laminated polarizing film was cut out to a size of 200 mm in parallel with the stretching direction of the polarizer and 20 mm in the direct direction, and a slit was put between the polarizing film and the retardation film with a cutter knife, and then the laminated polarizing film was bonded to the glass plate. With Tensilon, the polarizing film and the retardation film were peeled off in the direction of 90 degrees at a peel rate of 500 mm/min, and the peel strength was measured. Moreover, the infrared absorption spectrum of the peeling surface after peeling was measured by the ATR method, and the peeling interface was evaluated based on the following criteria.

1: Cohesive failure of the low elastic adhesive layer (a).

2: Cohesive failure of the retardation film.

In the above criteria, 2 means that the adhesive strength is very excellent because the adhesive strength is more than the cohesive strength of the film. On the other hand, 1 means that the adhesive force of the interface of a polarizing film/adhesive layer/phase difference film is insufficient (adhesive force is inferior).

<Peelability: Peel force>

The laminated polarizing film was cut out to a size of 200 mm in parallel with the stretching direction of the polarizer and 15 mm in the direct direction, and a slit was put between the polarizing film and the retardation film with a cutter knife, and then the laminated polarizing film was bonded to the glass plate. The polarizing film and the retardation film were peeled off at a peeling speed of 300 mm/min in the direction of 90 degrees by Tensilon, and the peeling strength (N/15 mm) was measured.

Comparative Examples 2 and 3 in Table 1 are pressure-sensitive adhesive layers in comparison with the low-elastic adhesive layer (a), and for reference, the ratio of the monomer components constituting the acrylic polymer forming the pressure-sensitive adhesive layer is described.

(A): Polyfunctional radical polymerizable compound

Aaronix M-270 represents polypropylene glycol diacrylate (manufactured by Dong-A Synthetic Corporation).

TPGDA: represents tripropylene glycol diacrylate.

Light acrylate 9EG-A represents ethylene glycol (average value 9 of the number of moles added) diacrylate (manufactured by Kyoe Chemical Co., Ltd.).

(B): Alkyl (meth)acrylate having an alkyl group having 2 to 12 carbon atoms

BA is n-butyl acrylate;

(C): (meth)acrylate having a hydroxyl group

2HEA is 2-hydroxyethyl acrylate;

4HBA is 4-hydroxybutyl acrylate;

PLACCEL FA1DDM represents a 2HEA caprolactone 1 mol adduct (made by Daicel Corporation).

(Others): radical polymerizable compounds other than the above

HEAA is hydroxyethylacrylamide (manufactured by Kojin Corporation);

ACMO represents acryloylmorpholine (manufactured by Kojin Corporation).

(E): Acrylic oligomer obtained by polymerizing (meth)acrylic monomer

UP-1190 represents an acrylic oligomer (ARUFON UP-1190, manufactured by Dong-A Synthetic Corporation) obtained by polymerizing a (meth)acrylic monomer.

(F): Radical polymerizable compound having an active methylene group

AAEM represents 2-acetoacetoxyethyl methacrylate (made by Nippon Synthetic Chemical Co., Ltd.).

(G): Radical polymerization initiator with hydrogen drawing action

KAYACURE DETX-S represents a radical polymerization initiator (diethyl thioxanthone, KAYACURE DETX-S, manufactured by Nippon Explosives Co., Ltd.) having a hydrogen drawing action.

(Photopolymerization initiator: other) (compound represented by general formula (2))

IRGACURE 907 represents 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (IRGACURE 907, manufactured by BASF).

1: polarizer
2: transparent protective film
P: polarizing film
3: Optical film (phase difference film)
a: low elasticity adhesive layer
b: adhesive layer

Claims (29)

As a laminated polarizing film in which a polarizing film and an optical film other than a polarizer are laminated via a low elastic adhesive layer (a),
In the polarizing film, a transparent protective film is laminated on at least one surface of the polarizer via an adhesive layer (b), and the low-elastic adhesive layer (a) is laminated on the transparent protective film,
The storage elastic modulus at 25°C of the low elastic adhesive layer (a) is 3.0 × 10 ⁵ to 1.0 × 10 ⁸ Pa,
Further, the laminated polarizing film, wherein the thickness of the low-elastic adhesive layer (a) is 0.1 to 5 µm. The method of claim 1,
The laminated polarizing film, characterized in that the optical film is a retardation film. The method of claim 1,
The laminated polarizing film, characterized in that the low-elastic adhesive layer (a) is a cured product layer obtained by irradiating an active energy ray-curable adhesive with an active energy ray. The method of claim 3,
A laminated polarizing film, wherein the active energy ray-curable adhesive contains substantially no organic solvent and is a liquid substance having a viscosity of 1 to 100 cp/25°C. The method of claim 3,
A laminated polarizing film, wherein the active energy ray-curable adhesive contains a radical polymerizable compound as a curable component. The method of claim 5,
A laminated polarizing film, wherein the radical polymerizable compound contains a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound (A). The method of claim 6,
When the total amount of the radical polymerizable compound is 100% by weight, the ratio of the polyfunctional radically polymerizable compound (A) is 1 to 65% by weight. The method of claim 6,
The multifunctional radical polymerizable compound (A) is a bifunctional (meth)acrylate having a weight average molecular weight of 200 to 4000. The method of claim 6,
A laminated polarizing film, wherein the radically polymerizable compound contains an alkyl (meth)acrylate (B) having an alkyl group having 2 to 18 carbon atoms. The method of claim 6,
The laminated polarizing film, wherein the radical polymerizable compound contains a (meth)acrylate (C) having a hydroxyl group. The method of claim 10,
The (meth)acrylate (C) having a hydroxyl group is a hydroxyl group-containing monofunctional (meth)acrylate having a weight average molecular weight of 160 to 3000. The method of claim 3,
The laminated polarizing film, wherein the active energy ray-curable adhesive contains a silane coupling agent (D). The method of claim 12,
The laminated polarizing film, wherein the silane coupling agent (D) is a silane coupling agent having no radical polymerizable functional group. The method of claim 3,
A laminated polarizing film, wherein the active energy ray-curable adhesive contains an acrylic oligomer (E) obtained by polymerizing a (meth)acrylic monomer. The method of claim 3,
A laminated polarizing film, wherein the active energy ray-curable adhesive contains a radically polymerizable compound (F) having an active methylene group and a radical polymerization initiator (G) having a hydrogen drawing action. The method of claim 15,
A laminated polarizing film, wherein the active methylene group is an acetoacetyl group. The method of claim 15,
A laminated polarizing film, wherein the radically polymerizable compound (F) having an active methylene group is acetoacetoxyalkyl (meth)acrylate. The method of claim 15,
The said radical polymerization initiator (G) is a thioxanthone type radical polymerization initiator, The laminated polarizing film characterized by the above-mentioned. The method of claim 1,
The adhesive layer (b) is an adhesive layer (b1) having a storage elastic modulus at 85°C of 1.0 × 10 ⁶ to 1.0 × 10 ¹⁰ Pa and a thickness of 0.03 to 3 μm. film. The method of claim 1,
In the polarizing film, the transparent protective film is formed on both surfaces of the polarizer through the adhesive layer (b),
The adhesive layer (b) is an adhesive layer (b1) having a storage elastic modulus at 85°C of 1.0 × 10 ⁶ to 1.0 × 10 ¹⁰ Pa and a thickness of 0.03 to 3 μm. Polarizing film. The method of claim 1,
In the polarizing film, the transparent protective film is formed on both surfaces of the polarizer through the adhesive layer (b),
The adhesive layer (b) on one side is an adhesive layer (b1) having a storage elastic modulus at 85°C of 1.0×10 ⁶ to 1.0×10 ¹⁰ Pa, and a thickness of 0.03 to 3 μm,
The adhesive layer (b) on the other side is an adhesive layer (b2) having a storage modulus of 1.0 × 10 ⁴ to 1.0 × 10 ⁸ Pa at 85°C and a thickness of 0.1 to 25 μm. Polarizing film. The method of claim 1,
The laminated polarizing film, wherein the polarizer has a thickness of 1 to 10 µm. The method of claim 1,
In the transparent protective film, at least one transparent protective film is a retardation film. The method of claim 1,
When the polarizing film and the optical film are forcibly peeled off, the low-elastic adhesive layer (a) is cohesively destroyed. The method of claim 1,
A laminated polarizing film, wherein a peeling force when the polarizing film and the optical film are forcibly peeled is 1 to 5 N/15 mm. As the manufacturing method of the laminated polarizing film in any one of Claims 1-25,
An active energy ray-curable adhesive for forming the low-elastic adhesive layer (a) on at least one surface of the transparent protective film on the side of the polarizing film on which the low-elastic adhesive layer (a) is laminated and the optical film With the coating process to apply,
A bonding step of bonding the polarizing film and the optical film, and
A laminated polarizing film comprising a bonding step of adhering the polarizing film and the optical film through the low elastic adhesive layer (a) obtained by irradiating the active energy ray to cure the active energy ray-curable adhesive. Manufacturing method. The method of claim 26,
The active energy ray has a ratio of an integrated illuminance in a wavelength range of 380 to 440 nm and an integrated illuminance in a wavelength range of 250 to 370 nm in a range of 100:0 to 100:50. A laminated optical film in which at least one laminated polarizing film according to any one of claims 1 to 25 is laminated. An image display device in which the laminated polarizing film according to any one of claims 1 to 25 is used.

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