TWI453472B - A composite polarizing plate, a laminated optical member, and an image display device using the same - Google Patents

Description

Composite polarizing plate, laminated optical member, and image display device using the same

The invention relates to a composite polarizing plate comprising a polarizer and a phase difference plate and a pressure sensitive adhesive layer. Further, the present invention relates to a laminated optical member in which the composite polarizing plate is laminated on another optical layer, and an image display device in which an image display element such as the composite polarizing plate or the laminated optical member and a liquid crystal cell is combined.

The liquid crystal display device has been used in desktop computers or electronic clocks since ancient times, but has rapidly expanded its use in recent years. In other words, from mobile devices such as mobile phones to large-sized televisions, liquid crystal display devices of various irrelevant screen sizes are used. Further, in addition to the liquid crystal display device, the organic electroluminescence (organic EL) display device has an increasing tendency centering on the use of the mobile device. The polarizing plates used in such image display devices are not only required to be increased, but also are required to be suitable for various uses.

A polarizing plate widely used in the image display device as described above is formed by adsorbing a polarizing element having a dichroic dye in a polyvinyl alcohol-based resin film, and laminating it with a liquid binder. The fluorene-based cellulose film is manufactured as a typical transparent protective layer. In this state, or in combination with various optical layers such as a phase difference plate or an optical compensation plate that exhibits predetermined optical characteristics via an adhesive or a pressure-sensitive adhesive, it is bonded to a liquid crystal cell or an organic EL. An image display element such as a component is used.

Fig. 9 is a cross-sectional typical view showing a general example of the conventional polarizing plate and the composite polarizing plate on which the phase difference plate is laminated. In other words, the transparent protective layers 2, 3 are provided on both faces of the polarizer 1 to constitute the polarizing plate 40. Further, on the other side of the transparent protective layer 3 side, the phase difference plate 5 is bonded via the pressure-sensitive adhesive layer 6, and the pressure-sensitive adhesive layer is attached to the image display element or the like on the outer side thereof. 7. The composite polarizing plate 41 is formed. The release film 9 which is provided on the outer side of the pressure-sensitive adhesive layer 7 until it is bonded to the image display element or the like, and which is falsely bonded to protect the surface thereof is a general example.

In recent years, in an image display device for mobile use such as a mobile phone, in terms of design or portability, the entire device is made thinner and lighter. Of course, the polarizing plates used in these applications are intended to be thinner and lighter. In addition, in order to be suitable for various use places, it is required to be thin and lightweight, and have the above-mentioned durability. In addition, in order to ensure the brightness when viewed from the front and from the inclined surface, a composite polarizing plate having a thin configuration in which the display image is not easily bleed or blurred is required.

Therefore, as shown in FIG. 9, the transparent protective layer 3 on the side of the other optical film such as the phase difference plate 5 is omitted, instead of providing the transparent protective layers 2 and 3 on both surfaces of the polarizer 1, and It is attempted to directly laminate other optical films such as the phase difference plate 5 via the adhesive or the pressure-sensitive adhesive on the polarizer 1, and the polarizing plate is made thinner. However, in this case, particularly when placed in a high-temperature environment or repeatedly placed in a high-temperature environment or a low-temperature environment, there is a problem that the polarizer 1 is stretched and contracted, and the dimensional change becomes large, and sufficient durability cannot be obtained.

Further, since the ancient times, it has been proposed to replace a triethylenesulfonated cellulose film as a transparent protective layer with another resin. For example, Japanese Laid-Open Patent Publication No. 2000-199819 (Patent Document 1) discloses that a resin solution is applied on one or both sides of a polarizer formed of a hydrophilic polymer by a solvent which does not dissolve the film. A polarizing plate having a transparent film layer is formed, and a protective layer formed of a transparent film is disposed on the transparent film layer. JP-A-2000-321430 (Patent Document 2) discloses a binder formed by a mixture of a polyvinyl alcohol-based binder and a two-liquid type binder on at least one side of a polyvinyl alcohol-based polarizer. A polarizing plate that laminates a protective film formed of a cyclic olefin resin. In JP-A-2001-305345 (Patent Document 3), it is disclosed that one side of a polarizer formed of at least a polyvinyl alcohol-based sheet is laminated via a raw polymer via an aqueous polymer-isocyanate-based adhesive. A polarizing plate of a protective film formed of an olefin resin.

When the transparent film or the cyclic olefin-based resin film (the original spinel-based resin film is also approximately synonymous) has a function of having a phase difference plate, it can be reduced to fit in the figure. A thin polarizing plate is formed like a member of the display element. Here, when a binder is used for forming a laminated polarizer and a transparent polymer film, when the binder is applied to a polarizer and the laminated polymer film is cured, the optical axis of the film is not easily made. Lamination of a certain angle to the axis of the polarizer is particularly problematic when forming an elliptical or circularly polarized composite polarizer useful in an image display device for mobile use. Further, when the polarizer and the transparent polymer film are bonded together only via a transparent adhesive, in the image display device using the object, the transmission type generates a shadow of the backlight or a display spot of the image display element, and half The transmissive type causes interference of light due to the unevenness of the surface of the reflecting plate, and causes an extravasation or blurring on the displayed image, which limits the visibility.

Further, it is known to bond a raw spintenyl resin film as described above to a polarizer using an adhesive (pressure-sensitive adhesive). For example, Japanese Laid-Open Patent Publication No. Hei 6-51117 (Patent Document 4) discloses a polarizing plate in which a thermoplastic saturated raw sinene-based resin film is laminated on one surface of at least a polarizer as a protective layer. Japanese Patent Publication No. 8-43812 (Patent Document 5) discloses a polarizing plate in which a protective film is laminated on both sides of a polarizer so that at least one of the protective films is simultaneously provided with a function of a phase difference plate. A protective film having a function as a phase difference plate is, for example, a thermoplastic raw spine-based resin. In the above-mentioned Patent Documents 4 and 5, a binder (pressure-sensitive adhesive) used for laminating a polarizer and a raw spinel-based resin film, such as natural rubber, synthetic rubber, elastomer, vinyl chloride/vinyl acetate Copolymer, polyvinyl alkane ether, polyacrylate, modified polyolefin resin adhesive, and the like.

In order to prevent the image from being exposed or blurred as described above and to improve the visibility, it is conceivable to provide a light-diffusing pressure-sensitive adhesive layer in which a light diffusing agent is incorporated in the adhesive. However, the light-diffusing pressure-sensitive adhesive layer formed by mixing a light diffusing agent in a general adhesive may cause insufficient durability due to insufficient cohesive force of the binder of the substrate.

Therefore, in the polarizing plate which is used for the purpose of reducing the thickness and the weight of the components, a polarizing plate which is thin and can maintain excellent durability and excellent visibility is desired. Further, in the step of laminating a polymer film having optical characteristics or other optical layers, it is desired to develop a thin polarizing plate using a pressure-sensitive adhesive having a high degree of freedom in production.

Patent Document 1: JP-A-2000-199819

Patent Document 2: JP-A-2000-321430

Patent Document 3: JP-A-2001-305345

Patent Document 4: Japanese Patent Publication No. 6-51117

Patent Document 5: Japanese Patent Publication No. 8-43812

An object of the present invention is to provide a composite in which a transparent protective layer is disposed on one surface of a polarizer and a phase difference plate is laminated on the other surface via a pressure-sensitive adhesive layer, thereby reducing thickness and weight of the member. In the polarizing plate, the pressure-sensitive adhesive layer which is bonded between the polarizer and the phase difference plate is applied to the pressure-sensitive adhesive layer existing between the pressure-sensitive adhesive layer provided on the outer side of the phase difference plate (including the same) At least one layer is composed of a light diffusing agent, which ensures the brightness of the image display device when viewed from the front and when viewed from the inclined surface, and is not easy to cause the image to be extravasated or blurred. Further, it is possible to further improve the pressure-sensitive adhesive layer to which the light-diffusing agent is blended, and a thin-type composite polarizing plate which exhibits good durability when placed in a high-temperature environment or repeated in a high-temperature environment and a low-temperature environment.

Further, another object of the present invention is to provide a laminated optical member which is excellent in durability and visibility by combining the composite polarizing plate with an optical layer which exhibits other optical functions. Further, another object of the present invention is to provide an image display device by combining the related composite polarizing plate or laminated optical member with an image display element of a liquid crystal cell.

In order to achieve the above object, the composite polarizing plate of the present invention has a transparent protective layer disposed on one surface of a polarizer formed of a polyvinyl alcohol resin film, and adhered to the other surface of the polarizer via a first pressure sensitive adhesive. At least one phase difference plate is laminated on the agent layer, and a composite polarizing plate formed by disposing a second pressure-sensitive adhesive layer on the outer side of the phase difference plate located farthest from the polarizer is characterized in that it contains the first pressure-sensitive adhesive layer. The agent layer and the second pressure-sensitive adhesive layer, at least one of the pressure-sensitive adhesive layers present between the two is provided with a light diffusing agent, and has a storage elastic modulus of 0.15 to 10 MPa at 23 ° C. The sexy pressure-sensitive adhesive layer is preferably composed of a light-diffusing pressure-sensitive adhesive layer having a storage modulus of 0.15 to 10 MPa at 23 ° C and 80 ° C.

Thus, by laminating the phase difference plates on one side of the polarizer via the first pressure-sensitive adhesive layer, a thin and lightweight composite polarizing plate is formed by reducing the number of members. Further, by using at least one of the pressure-sensitive adhesive layers present between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer to be combined with the light diffusing agent, it is possible to ensure the use of the light-diffusing agent. The brightness of the image display device of the composite polarizing plate when viewed from the front and when viewed from the oblique direction is less likely to cause an infiltration or blurring of the displayed image, and the visibility is high. Further, the pressure-sensitive adhesive layer to which the light diffusing agent is blended is a light having a high storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. The diffusion-type pressure-sensitive adhesive layer is formed to prevent the problem of durability due to insufficient cohesive force of the pressure-sensitive adhesive layer when placed in a high-temperature environment or repeatedly placed in a high-temperature environment or a low-temperature environment.

In the above composite polarizing plate, at least two layers of the pressure-sensitive adhesive layer are present, at least one of which contains a light diffusing agent, and is displayed at 23 ° C, 0.15 to 10 MPa, preferably at 23 ° C and 80 ° C. The light-diffusing pressure-sensitive adhesive layer having a storage modulus of 0.15 to 10 MPa may be formed, and usually one of the layers satisfies the condition. Further, the light-diffusing sexy pressure-sensitive adhesive layer has a haze value of 5% or more. When the haze value is 5% or more, the visibility is improved. Further, in terms of durability and adhesiveness, it is preferably 90% or less. In view of the above, the haze value is preferably in the range of 20 to 90%, more preferably 30 to 75%. Further, the light-diffusing pressure-sensitive adhesive layer preferably has a thickness of from 1 to 40 μm. When the thickness is less than 1 μm, the adhesiveness or durability becomes insufficient. Further, when it is more than 40 μm, problems such as residual solvent may occur. From this point of view, the thickness of the light-diffusing sexy pressure-sensitive adhesive layer is preferably from 3 to 25 μm. Further, the first pressure-sensitive adhesive layer that bonds the polarizer to the phase difference plate is not limited to whether or not it has a light diffusing agent, and the storage modulus is 0.15 to 10 MPa at 23 ° C, preferably 23 ° C and A value between 0.15 and 10 MPa at 80 ° C is preferred. When the storage modulus at 23 ° C is 0.15 MPa or more, even when only the composite polarizing plate of the present invention having a transparent protective layer on one side of the polarizer, excellent dimensional stability can be obtained even in a high temperature environment, and further, at 23 ° C When the storage modulus is 10 MPa or less, sufficient adhesion between the polarizer and the phase difference plate can be exhibited.

In the composite polarizing plate described above, when the phase difference plate is one, the first pressure-sensitive adhesive layer existing between the polarizer and the phase difference plate, and the second pressure sensitive force disposed on the outer side of the phase difference plate Any one of the binder layers is a light-diffusing pressure-sensitive adhesive layer containing a light diffusing agent and exhibiting a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. Alternatively, any one of the first pressure-sensitive adhesive layers in the bonded polarizer and the phase difference plate contains a light diffusing agent, and the pressure-sensitive adhesive layer is formed to exhibit 0.15 to 10 MPa at 23 ° C, preferably in A light-diffusing pressure-sensitive adhesive layer having a storage modulus of 0.15 to 10 MPa at 23 ° C and 80 ° C is preferred.

Further, when two retardation plates are used in the above composite polarizing plate, it is preferable that the two retardation plates are bonded via the third pressure-sensitive adhesive layer. At this time, the first pressure-sensitive adhesive layer existing between the polarizer and the phase difference plate, the second pressure-sensitive adhesive layer disposed on the outer side of the phase difference plate farthest from the polarizer, and 2 In the third pressure-sensitive adhesive layer of the phase difference plate, any layer contains a light diffusing agent and exhibits a storage elastic modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. The light-diffusing pressure-sensitive adhesive layer may be such that a first pressure-sensitive adhesive layer that bonds the polarizer and the phase difference plate or a third pressure-sensitive adhesive layer that bonds the two phase difference plates contains a light diffusing agent. Further, the pressure-sensitive adhesive layer is preferably 0.15 to 10 MPa at 23 ° C, and preferably has a storage modulus of 0.15 to 10 MPa at 23 ° C and 80 ° C.

In the composite polarizing plate of the above, the second pressure-sensitive adhesive layer disposed on the outer side of the retardation plate farthest from the polarizer is processed until it is bonded to the bonded body. It is preferable to have a release film which is treated with a release agent such as polyoxyalkylene on the exposed surface.

The laminated optical member of the present invention is formed by a laminate of any one of the specific composite polarizing plates described above and an optical layer having other optical functions. An optical layer having other optical functions, such as a hard coating layer, an antireflection layer, a surface treatment layer of an antiglare layer, or a reflective layer, a semi-transmissive reflective layer, a brightness enhancement film, or the like.

For example, in the above composite polarizing plate, a surface of the hard protective layer, the antireflection layer, the antiglare layer, or the like may be provided on the opposite side of the transparent protective layer disposed on one surface of the polarizer and the polarizing surface. . Further, in the above composite polarizing plate, a reflective layer or a semi-transmissive reflective layer may be formed on the opposite side of the transparent protective layer provided on one side of the polarizer and the polarizing surface is connected to form a reflective or semi-transmissive layer. Reflective composite polarizer. Further, in the composite polarizing plate described above, the brightness improving film may be bonded to the opposite side of the transparent protective layer disposed on one surface of the polarizer and the polarizing member connecting surface via an adhesive or a pressure sensitive adhesive. A composite polarizing plate that reuses light from a light source.

The image display device of the present invention is provided with the above composite polarizing plate or laminated optical member, and an image display element such as a liquid crystal cell or an organic EL element. The above-described composite polarizing plate or laminated optical member is disposed on at least one side of the image display element. Generally, the second pressure-sensitive adhesive layer disposed on the outer side of the phase difference plate farthest from the polarizer in the composite polarizing plate or the laminated optical member is bonded to the composite polarizing plate or the laminated optical member. On the image display element.

[Effects of the Invention]

In the composite polarizing plate of the present invention, since the retardation film is laminated on one surface of the polarizer via the first pressure-sensitive adhesive layer, the number of members can be reduced, and the thickness can be reduced. Further, the second pressure-sensitive adhesive layer including the first pressure-sensitive adhesive layer and the outer side of the phase difference plate located farthest from the polarizer is present in the pressure-sensitive adhesive layer between the two a light-diffusing sexy pressure-sensitive adhesive having at least one layer containing a light diffusing agent and having a predetermined storage modulus at 23 ° C (preferably at 23 ° C and 80 ° C) with the pressure-sensitive adhesive layer to which the light diffusing agent is added Since it is composed of layers, it has high durability and excellent visibility.

Further, the laminated optical member of the present invention is one in which an optical layer having another optical function is laminated on the above composite polarizing plate. Of course, it is a thin and lightweight structure, and is excellent in durability and visibility. Then, these composite polarizing plates or laminated optical members can produce an image display device which is thin, excellent in durability and visibility.

In the following, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Composite polarizer]

Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of a composite polarizing plate of the present invention.

In the present invention, as shown in the figure, the transparent protective layer 2 is disposed on one surface of the polarizer 1, and the phase difference plate 5 is laminated on the other surface of the polarizer 1 via the first pressure-sensitive adhesive layer 6. Further, the second pressure-sensitive adhesive layer 7 is disposed on the outer side of the phase difference plate 5 to form a composite polarizing plate 11. The peeling film 9 which is disposed on the outer side of the second pressure-sensitive adhesive layer 7 outside the phase difference plate 5 until it is attached to the image display element and provided with a false adhesion protection surface is a general example. A plurality of retardation plates 5 may be formed. In this case, the second pressure-sensitive adhesive layer 7 is disposed on the outer side of the phase difference plate located farthest from the polarizer 1.

Next, a first pressure-sensitive adhesive layer 6 for bonding the polarizer 1 and the phase difference plate 5, and a second pressure-sensitive adhesive layer 7 located outside the phase difference plate 5, and a pressure-sensitive adhesive layer existing therebetween are provided. At least one of the layers is composed of a light-diffusing pressure-sensitive adhesive layer containing a light diffusing agent and exhibiting a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. In general, since the storage modulus is gradually decreased with an increase in temperature, the storage modulus at 23 ° C and 80 ° C may be within the above range, and the storage modulus in the above range may be exhibited in the range.

As shown in Fig. 1, when one phase difference plate 5 is used, at least one of the first pressure-sensitive adhesive layer 6 and the second pressure-sensitive adhesive layer 7 contains the light diffusing agent as described above, and is displayed. The light-diffusing pressure-sensitive adhesive layer having a storage modulus of 0.15 to 10 MPa at 23 ° C and 80 ° C is preferable, and it is preferably 0.15 to 10 MPa at 23 ° C. In this case, the first pressure-sensitive adhesive layer 6 disposed on the opposite side to the connection surface of the transparent protective layer 2 of the polarizer 1 can be obtained as a composite polarizing plate having improved light diffusion efficiency and good visibility. The light-diffusing agent is contained, and the pressure-sensitive adhesive layer 6 is a light-diffusing elastic pressure-sensitive adhesive which exhibits a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. The layer is preferred. In addition, in the high-temperature environment, no foaming occurs in the adhesive layer, and the light-diffusing sexy pressure-sensitive adhesive layer is used as an image display device without a brightness spot and a uniform brightness over a long period of time. The average particle diameter of the light diffusing agent in the layer is 0.1 to 20 μm, and the storage elastic modulus of the layer at 23 ° C is 0.3 to 10 MPa, and the haze value is preferably 5% or more, preferably 23 ° C and 80 ° C. The storage modulus is preferably from 0.3 to 10 MPa. Further, when the first pressure-sensitive adhesive layer 6 is used as the light-diffusing pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer 7 provided through the phase difference plate 5 can be freely designed. In other words, since the liquid crystal cell is expensive, it is desirable to peel off and reuse the liquid crystal cell when the laminated composite polarized light is damaged. In this case, when the first pressure-sensitive adhesive layer 6 is used as a composite polarizing plate composed of a light-diffusing pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer 7 can be used as a re-peeling pressure-sensitive adhesive layer to enable composite polarization. The visibility and re-peelability of the board are two. Further, since a thin image display device is required, it is desired to grind and thin the glass surface of the liquid crystal cell, but at this time, the glass surface is roughened. When attached to the roughened glass surface, the light-diffusing pressure-sensitive adhesive layer of the first pressure-sensitive adhesive layer 6 can be used to prevent extravasation or blurring, and the second pressure-sensitive adhesive layer can be 7 Buried in the rough surface to form a pressure-sensitive adhesive layer with high followability. Further, in terms of durability, the second pressure-sensitive adhesive layer 7 disposed on the outer side of the image display element or the like disposed on the outer side of the phase difference plate 5 contains a light diffusing agent, and the pressure-sensitive adhesive layer 7 is preferably a light-diffusing pressure-sensitive adhesive layer which exhibits a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. In addition, the composite polarizing plate having the light-diffusing pressure-sensitive adhesive layer has good durability at the time of bonding, and does not cause bubbling in the adhesive layer in a high-temperature environment, and is displayed as an image. In the case where the device has no brightness spots and can obtain uniform brightness over a long period of time, the light-diffusing pressure-sensitive adhesive layer has an average particle diameter of 0.1 to 20 μm in the layer, and the layer is at 23 ° C. The storage elastic modulus is preferably 0.3 to 10 MPa, and the haze value is preferably 5% or more, and the storage elastic modulus at 23 ° C and 80 ° C is more preferably 0.3 to 10 MPa.

Fig. 2 is a schematic cross-sectional view showing another example of the layer configuration of the composite polarizing plate of the present invention. In the example shown in the figure, the first phase difference plate 4 and the second phase difference plate 5 are used, and the two phase difference plates are laminated via the third pressure-sensitive adhesive layer 8. In other words, in this example, the transparent protective layer 2 is disposed on one surface of the polarizer 1, and the first phase difference plate 4 is laminated on the other surface of the polarizer 1 via the first pressure-sensitive adhesive layer 6, and the layer is sequentially formed on the outer side thereof. The third pressure-sensitive adhesive layer 8 and the second phase difference plate 5 are joined together, and the second pressure-sensitive adhesive layer 7 is disposed on the outer side of the second phase difference plate 5 to form the composite polarizing plate 12. When laminating three or more retardation plates, it is preferable that each retardation film is bonded via a pressure-sensitive adhesive layer. The outer surface of the second pressure-sensitive adhesive layer 7 on the outer side of the second phase difference plate 5 is usually provided with a release film 9 which is falsely bonded to protect the surface thereof until it is bonded to an image display element or the like, and FIG. The examples shown are the same.

The form shown in FIG. 2 is the first pressure-sensitive adhesive layer 6 that bonds the polarizer 1 and the first phase difference plate 4, the second pressure-sensitive adhesive layer 7 that is located outside the second phase difference plate 5, and At least one of the third pressure-sensitive adhesive layers 8 joining the first phase difference plate 4 and the second phase difference plate 5 contains a light diffusing agent and is displayed at 23 ° C for 0.15 to 10 MPa, preferably 23 It is composed of a light-diffusing pressure-sensitive adhesive layer having a storage modulus of 0.15 to 10 MPa at ° C and 80 ° C. In this case, the composite polarizing plate having improved light diffusion efficiency and good visibility is laminated with a transparent protective layer 2, a polarizer 1, a first pressure-sensitive adhesive layer 6, a phase difference plate 4, and the like. In the composite polarizing plate of the present invention, the first pressure-sensitive adhesive layer 8, the phase difference plate 5, the second pressure-sensitive adhesive layer 7, and the release film 9, the first pressure-sensitive adhesive layer 6, or the third pressure-sensitive adhesive Any of the layers 8 is provided with a light diffusing agent, and the pressure-sensitive adhesive layer exhibits a light transmittance of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. A sexy pressure-bonding layer is preferred. In addition, in a high-temperature environment, there is no bubbling in the adhesive layer, no brightness spot as an image display device, and uniform brightness over a long period of time, the light-diffusing sexy pressure-sensitive adhesive layer The average particle diameter of the light diffusing agent in the layer is 0.1 to 20 μm, and the storage elastic modulus of the layer at 23 ° C is 0.3 to 10 MPa, and the haze value is preferably 5% or more, preferably at 23 ° C. The storage modulus at 80 ° C is more preferably 0.3 to 10 MPa. Moreover, when any one of the first pressure-sensitive adhesive layer 6 or the third pressure-sensitive adhesive layer 8 is the light-diffusing pressure-sensitive adhesive layer, the second pressure-sensitive adhesive adhered to the liquid crystal cell or the like can be freely designed. Layer 7, also preferred. In other words, when the liquid crystal cell is bonded at a high price and the composite polarizing plate is damaged, it is desired to peel off and reuse the liquid crystal cell. At this time, when any one of the first pressure-sensitive adhesive layer 6 or the third pressure-sensitive adhesive layer 8 is a light-diffusing pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer 7 can be used as the second pressure-sensitive adhesive layer 7 Further, the elastic pressure-sensitive adhesive layer is peeled off, and the visibility and re-peelability of the composite polarizing plate can be made two. Further, since a thin image display device is required, it is desired to grind and thin the glass surface of the liquid crystal cell, and at this time, the glass surface is roughened. When the surface is attached to the roughened glass surface, the light-diffusing pressure-sensitive adhesive layer of the first pressure-sensitive adhesive layer 6 or the third pressure-sensitive adhesive layer 8 can prevent the extravasation or blurring. Further, the second pressure-sensitive adhesive layer 7 can be embedded in the rough surface to form a pressure-sensitive adhesive layer having high followability. Further, in terms of durability, the second pressure-sensitive adhesive layer 7 located outside the phase difference plate 5 farthest from the polarizer 1 or the third pressure-sensitive adhesive layer 8 bonded to the two phase plate is contained The light diffusing agent is preferably a light-diffusing/pressure-sensitive adhesive layer which exhibits a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. In addition, the composite polarizing plate having the light-diffusing pressure-sensitive adhesive layer has good durability at the time of bonding, and does not cause bubbling in the adhesive layer in a high-temperature environment, and is displayed as an image. In the case where the device has no brightness spots and a uniform brightness over a long period of time, the light-diffusing pressure-sensitive adhesive layer has an average particle diameter of 0.1 to 20 μm in the layer, and the layer is at 23 ° C. The storage elastic modulus is preferably 0.3 to 10 MPa, and the haze value is preferably 5% or more, and the storage elastic modulus at 23 ° C and 80 ° C is more preferably 0.3 to 10 MPa.

Thus, the present invention includes the first pressure-sensitive adhesive layer 6 disposed on one surface of the polarizer 1 and bonded to the phase difference plate 5 or 4, and the outer surface of the phase difference plate 5 located farthest from the polarizer 1 The second pressure-sensitive adhesive layer 7 contains a light diffusing agent in at least one of the pressure-sensitive adhesive layers present between the two-phase difference. By arranging the pressure-sensitive adhesive containing the light diffusing agent, it is ensured that the image display device using the composite polarizing plate has brightness when viewed from the front, that is, when viewed from a slope, and is not easily exposed or blurred. . Further, the pressure-sensitive adhesive layer to which the light diffusing agent is added is light having a storage elastic modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. It is composed of a diffusion-type pressure-sensitive adhesive layer. Thereby, the composite polarizing plate or the image display device using the same can improve the durability when exposed to a high temperature environment and repeated in a high temperature environment and a low temperature environment. Moreover, the composite polarizing plate having the light-diffusing pressure-sensitive adhesive layer has good durability at the time of bonding, and does not cause bubbling in the adhesive layer in a high-temperature environment, and the composite polarizing plate is used. When the obtained image display device has no brightness spots and can obtain uniform brightness over a long period of time, the light diffusion-type pressure-sensitive adhesive layer has an average particle diameter of 0.1 to 20 μm in the layer, and the average particle diameter of the layer is 0.1 to 20 μm. The storage elastic modulus of the layer at 23 ° C is preferably 0.3 to 10 MPa, and the haze value is preferably 5% or more, and the storage elastic modulus at 23 ° C and 80 ° C is more preferably 0.3 to 10 MPa.

In the present invention, as shown in Figs. 1 and 2, the first pressure-sensitive adhesive layer 6 is directly disposed on one surface of the polarizer 1, and the phase difference plate 5 or 4 is bonded thereto. Therefore, when compared with a conventional polarizing plate to which a transparent protective layer is attached on both surfaces of a polarizer, the ability to suppress the expansion and contraction of the polarizer 1 when exposed to a high temperature environment is small. Therefore, the first pressure-sensitive adhesive layer 6 that bonds the polarizer 1 and the phase difference of 5 or 4 is not limited by the presence or absence of the light diffusing agent, and the storage elastic modulus is 0.15 to 10 MPa at 23 ° C, preferably A value between 0.15 and 10 MPa at 23 ° C and 80 ° C is preferred. Further, when the pressure-sensitive adhesive layer 6 is used as a light-diffusing pressure-sensitive adhesive layer, the light diffusing agent of the layer has an average particle diameter of 0.1 to 20 μm and a storage modulus at 23 ° C of 0.3 to 10 MPa. The haze value of the layer is preferably 5% or more, and the storage modulus at 23 ° C and 80 ° C is more preferably 0.3 to 10 MPa. By forming the first pressure-sensitive adhesive layer 6 having the junction polarizer 1 and the phase difference 5 or 4 as high in the storage modulus, it is possible to suppress the composite polarizing plate or the image display device using the same from being exposed to high temperatures. Or repeat the dimensional change of the polarizer 1 stretching in a high temperature environment and a low temperature environment.

In the following, each member constituting the composite polarizing plate of the present invention will be described.

[Polarizer]

The polarizer 1 is a film having a function of taking out linear polarized light from incident natural light. Specifically, a polarizing film in which a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film can be used. The polyvinyl alcohol-based resin constituting the polarizer 1 can be obtained by saponifying a polyvinyl acetate-based resin. A polyvinyl acetate-based resin, in addition to polyvinyl acetate of a homopolymer of vinyl acetate, such as a copolymer of vinyl acetate and other monomers copolymerizable with the product. Other monomers copolymerizable with vinyl acetate, such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having ammonium groups, and the like. The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin can be further modified, for example, by using an aldehyde-modified polyvinyl acetal or polyvinyl acetal. Further, the degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

The film formed of the polyvinyl alcohol resin is used as a raw material film of the polarizer 1. The method of forming a film of a polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The film thickness of the raw material film formed from the polyvinyl alcohol-based resin is not particularly limited, and is, for example, about 1 μm to 150 μm. When the easiness of stretching is considered, the film thickness is preferably 10 μm or more.

The polarizer 1 is a step of one-axis stretching of the polyvinyl alcohol-based resin film, and the polyvinyl alcohol-based resin film is dyed with a dichroic dye and adsorbed with the dichroic dye to adsorb a dichroic dye. The polyvinyl alcohol-based resin film is treated with a boric acid aqueous solution, and is subjected to a step of washing with the aqueous boric acid solution and then washing with water. The dichroic dye system uses iodine or a dichroic organic dye.

[Transparent protective layer]

On one side of the polarizer 1, a transparent protective layer 2 is disposed. In the transparent protective layer 2, a suitable resin film can be used. Specifically, a film formed of a resin excellent in transparency, uniform optical characteristics, mechanical strength, thermal stability, and the like is preferably used. For example, a cellulose resin film of triethyl fluorenyl cellulose or diethyl hydrazine cellulose, such as polyethylene terephthalate or polyethylene isophthalate, polybutylene terephthalate A polyester resin film, such as an acrylic resin film such as poly[(methyl) methacrylate] or poly[(methyl) acrylate], a polycarbonate resin film, a polyether fluorene film, or a polyfluorene system A resin film, a polyimide film, a polyolefin resin film, a cyclic olefin such as raw spinel, or a cyclic olefin resin film as a monomer. The polarizer 1 is bonded to the transparent protective layer 2, and a binder or a pressure sensitive adhesive can be used.

On the surface of the transparent protective layer 2, a surface treatment layer of a hard coating layer, an antireflection layer, an antiglare layer or the like may be provided as needed. The hard coating layer is formed by preventing the surface of the polarizing plate from being scratched, and is mainly composed of an ultraviolet curable resin, for example, a resin selected from an acrylic or polyoxyalkylene system, and the adhesion to the transparent protective layer 2 or hardness. Excellent, formed on the surface of the transparent protective layer 2. The antireflection layer is formed for the purpose of preventing light reflection outside the surface of the polarizing plate, and can be formed by a known method. Further, the anti-glare layer is formed to prevent the visibility of the external light from being reflected on the surface of the polarizing plate, and is generally roughened by, for example, a sandblasting method or an embossing method, or The coating liquid in which the transparent fine particles are mixed in the ultraviolet curable resin is applied and cured, and the uneven protective layer 4 is formed on the surface of the transparent protective layer 4.

[phase difference plate]

On the other side of the polarizer 1, a first pressure-sensitive adhesive layer 6 is provided, and at least one phase difference plate 5 and/or 4 is attached thereto. The retardation plates 4 and 5 can be made of the same various transparent resin films as those exemplified as the resin constituting the transparent protective layer 2, particularly those having the characteristics required as the phase difference plate, that is, those having a suitable refractive index and optical uniformity. The protection function of the polarizer 1 is used for the purpose of compensating for the phase difference (including the compensation of the viewing angle) by the liquid crystal cell. For example, the image display device used in the past is not particularly limited, and a birefringent film formed of an extended film of various transparent resins, a disc-shaped liquid crystal or a nematic liquid crystal is fixedly fixed on a substrate film. The liquid crystal layer or the like is formed. When the liquid crystal layer is fixed to the base film, it is preferable to use a cellulose resin film such as triacetyl cellulose as the base film for supporting the alignment liquid crystal layer.

The resin forming the birefringent film is, for example, a polycarbonate-based, polyvinyl alcohol-based, polystyrene-based, polymethyl methacrylate-based, polypropylene-based polyolefin-based, polyacrylic-based or polyacrylamide-based, The cyclic olefin of the raw spinel is a monomeric cyclic polyolefin system or the like. The stretch film can be handled in a suitable manner such as one axis or two axes. Further, a birefringent film which controls the refractive index in the thickness direction of the film by applying a shrinking force and/or an elongation force to the heat-shrinkable film may be used.

The phase difference plate is particularly preferably a wavelength plate (λ/2 plate or λ/4 plate) of an elliptically polarized or circularly polarized composite polarizing plate used for forming an image display device for mobile use. The elliptically polarized or circularly polarized composite polarizing plate has the function of changing the elliptically polarized light or the circularly polarized light when the incident polarized light is linearly polarized, and changing the linear polarized light when the incident polarized light is elliptically polarized or circularly polarized. In particular, it is possible to change the elliptically polarized or circularly polarized light into a linearly polarized light, and to change the linearly polarized light into a elliptically polarized or circularly polarized phase difference plate, and to use an in-plane phase called 1/4 wavelength for the wavelength λ of the visible light. Poor λ/4 board. Further, the λ/2 plate which imparts an in-plane retardation of 1/2 wavelength to the wavelength λ of the visible light has a function of rotating the direction of the linearly polarized light. For the λ/4 plate, for example, an in-plane phase difference of about 90 to 160 nm can be used. Further, for the λ/2 plate, for example, an in-plane retardation of about 200 to 300 nm can be used.

Further, the above-described elliptically polarizing type composite polarizing plate is effective for preventing coloring due to birefringence of liquid crystal in a liquid crystal display device, and a circularly polarizing type composite polarizing plate is used for a reflective or semi-transmissive reflection type image. It can be effectively used for the purpose of improving the brightness in the display device. The circularly polarized composite polarizing plate also has a function of preventing reflection.

As shown in Fig. 1, when one phase difference plate is used, for example, a λ/4 plate is used as the appropriate phase difference plate 5. At this time, the polarizer 1 and the λ/4 plate 5 are laminated in such a manner that the latter has a retardation axis of about 45° or about 135°, and the composite polarizing plate 11 has circular polarization. Board function.

Further, as shown in Fig. 2, when two retardation plates are used, for example, an appropriate phase difference plate is combined, and the first phase difference plate 4 disposed on the side of the polarizer 1 is a λ/2 plate, and the distance polarizer 1 is The second phase difference plate 5 disposed on the farthest side is a λ/4 plate. At this time, for example, by the polarization transmission axis of the polarizer 1, the slow phase axis of the λ/2 plate 4 of the first phase difference plate is about 15°, and secondly, the λ/4 plate of the second phase difference plate is made. The slow phase axis of 5 is about 75°, or the slow phase axis of the λ/2 plate 4 of the first phase difference plate is about 75°, and secondly, the slow phase axis of the λ/4 plate 5 of the second phase difference plate When it is disposed at about 195°, the composite polarizing plate 12 has a function as a circular polarizing plate when it passes through a wide wavelength range.

[pressure-sensitive adhesive layer]

The first pressure-sensitive adhesive layer 6 that bonds the polarizer 1 and the phase difference plate 5 or 4, the second pressure-sensitive adhesive layer 7 disposed on the outer side of the phase difference plate 5 farthest from the polarizer, and the use When the two or more retardation plates are joined, the third pressure-sensitive adhesive layer 8 of each of the plates may be formed of an adhesive material of a matrix polymer (referred to as an adhesive resin) having adhesiveness, and these pressure-sensitive adhesives may be used. At least one of the layers is a light-diffusing pressure-sensitive adhesive layer formed of an adhesive material containing an adhesive resin and a light diffusing agent. Further, when a layer formed of an adhesive material (hereinafter referred to as an adhesive material layer) directly forms a pressure-sensitive adhesive layer, an energy line such as heat or ultraviolet rays or electron beams is applied to the adhesive material layer. A pressure sensitive adhesive layer is formed.

The adhesive base polymer (adhesive resin) is specifically a base polymer such as an acrylic, rubber, urethane or polyvinyl ether. Further, it may be an energy ray hardening type or a thermosetting type. Among these, an adhesive resin having an acrylic resin excellent in transparency, weather resistance, heat resistance, and the like as a base polymer is preferable, and specifically, the adhesive resin is, for example, (A) an acrylic copolymer and (B). The active energy ray-curable compound is preferably formed. (A) An acrylic copolymer such as a (meth)acrylate copolymer. Here, (meth)acrylic means both acrylic acid and methacrylic acid, and is similar to other similar terms.

The above (meth) acrylate-based copolymer is preferably one having a crosslinking point which is crosslinkable by various crosslinking methods. The (meth) acrylate-based copolymer having such a cross-linking point is not particularly limited, and any of the (meth) acrylate-based copolymers conventionally used as the resin component of the binder can be appropriately selected.

A (meth) acrylate-based copolymer having the cross-linking point, for example, a (meth) acrylate having a carbon number of 1 to 20 in an alkyl group of an ester moiety, and a crosslinkable functional group in a molecule Copolymers of monomers and other monomers which are used as desired are preferred. Here, the alkyl group of the ester moiety has a carbon number of 1 to 20 (meth) acrylate, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( Methyl)butyl acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid Octyl ester, decyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and the like. These may be used alone or in combination of two or more.

Further, the monomer having a crosslinkable functional group in the molecule preferably has at least one hydroxyl group, carboxyl group, amine group, and decylamine, and specifically, for example, 2-hydroxyethyl (meth)acrylate, (methyl) ) 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxy butyl (meth) acrylate a hydroxyalkyl (meth) acrylate such as an ester; a propylene oxime such as (meth) acrylamide, N-methyl (meth) acrylamide, or N-methylol (meth) acrylamide ; (meth)acrylic acid monomethylaminoethyl acrylate, (meth)acrylic acid monoethylaminoethyl ester, (meth)acrylic acid monomethylaminopropyl acrylate, (meth)acrylic acid monoethylamine A monoalkylamino (meth)acrylate such as propyl ester; an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid or citraconic acid. These monomers may be used singly or in combination of two or more.

In the adhesive resin, the (meth)acrylate copolymer used as the component (A) is not particularly limited in terms of its copolymerization form, and may be any of random, block, and graft copolymers. One. Further, the molecular weight is usually a weight average molecular weight of 500,000 or more. When the weight average molecular weight is 500,000 or more, the adhesion to the adherend or the adhesion durability is sufficient, and no floating or peeling occurs. When the adhesion and the adhesion durability are considered, the weight average molecular weight is preferably from 600,000 to 2,200, and more preferably from 700,000 to 2,000,000. Further, the weight average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

Further, in the (meth) acrylate-based copolymer, the content of the monomer unit having a crosslinkable functional group in the molecule is preferably in the range of 0.01 to 10% by mass. When the content is 0.01% by mass or more, the crosslinking proceeds to be sufficient and the durability is improved by reacting with the crosslinking agent described below. Further, when the amount is 10% by mass or less, the degree of crosslinking becomes too high, and the suitability for the liquid crystal glass unit or the phase difference is not lowered, which is preferable. When the durability is compatible with the liquid crystal cell or the phase difference plate, the content of the monomer unit having the crosslinkable functional group is preferably 0.05 to 7.0% by mass, and more preferably 0.2 to 6.0% by mass. good. In the present invention, the (meth) acrylate-based copolymer of the component (A) may be used alone or in combination of two or more.

In the adhesive resin, the active energy ray-curable compound used as the component (B) is preferably a polyfunctional (meth)acrylic monomer having a molecular weight of less than 1,000.

a polyfunctional (meth)acrylic monomer having a molecular weight of less than 1,000, such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentane Diol (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxy trimethyl acetic acid neopentyl glycol di (a) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, di Propylene oxiranyl ethyl) isomeric cyanurate, allylated cyclohexyl di(meth) acrylate, dimethylol dicyclopentane di(meth) acrylate, ethylene oxide modified hydrogen benzene Di(meth) acrylate dicarboxylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylolpropane di(meth) acrylate, adamantane di(meth) acrylate 2-functional type of ester, 9,9-bis[4-(2-propenyloxyethoxy)phenyl]anthracene, etc.; trimethylolpropane tri(meth)acrylate, dipentaerythritol tris(methyl) Acrylate, propionic acid modified dipentaerythritol (meth) acrylate, pentaerythritol tri(meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, ginseng (propylene oxyethyl) isomeric cyanurate, etc. a trifunctional type; a tetrafunctional type such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; a 5-functional type such as propionic acid-modified dipentaerythritol penta(meth)acrylate; A penta-functional type such as pentaerythritol hexa(meth) acrylate or caprolactone-modified dipentaerythritol hexa(meth) acrylate.

In the present invention, these polyfunctional (meth)acrylate monomers may be used alone or in combination of two or more. The constructor is preferred. The annular structure may have a carbon ring structure or a heterocyclic structure, and may have a single ring structure or a polycyclic structure. The polyfunctional (meth)acrylic monomer, for example, di(acryloyloxyethyl)isocyanate, ginseng(propyleneoxyethyl)isocyanate, etc. Cyanate ester constructor, dimethylol dicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modified trimethylol Propane diacrylate, adamantane diacrylate, and the like are preferred.

Further, an active energy ray-curable acrylate-based oligomer of the component (B) can be used. Examples of the acrylate-based oligomer include a polyester acrylate acrylate type, an epoxy acrylate type, a urethane acrylate type, a polyether acrylate type, and a polybutadiene acrylate type. Polyoxyalkylene acrylate or the like.

Here, the polyester acrylate-based oligomer, for example, a hydroxyl group of a polyester oligomer having a hydroxyl group at both terminals obtained by condensing a polyvalent carboxylic acid and a polyhydric alcohol is esterified with (meth)acrylic acid, or The hydroxyl group at the terminal of the oligomer obtained by adding an oxyalkylene group to a polyvalent carboxylic acid is obtained by esterification with (meth)acrylic acid. An epoxy acrylate oligomer, for example, by reacting and esterifying an oxirane ring of a lower molecular weight bisphenol type epoxy resin or a novolak type epoxy resin with (meth)acrylic acid Got it. Further, a carboxyl group-modified epoxy acrylate oligomer in which a part of the epoxy acrylate-based oligomer is modified with a dicarboxylic acid anhydride can also be used. A urethane acrylate oligomer, for example, a polyurethane oligomer obtained by reacting a polyether polyol or a polyester polyol with a polyisocyanurate (formic acid) Acrylate and obtained, the polyol acrylate-based oligomer can be obtained by esterifying a hydroxyl group of a polyether polyol with (meth) acrylate.

The weight average molecular weight of the acrylic oligomer is preferably in a range of from 50,000 to 50,000, more preferably from 500 to 50,000, more preferably from 3,000 to 40,000, in terms of a standard polystyrene conversion measured by a GPC method. These acrylate-based oligomers may be used alone or in combination of two or more.

In the present invention, an addition acrylate polymer in which a group having a (meth)acryl fluorenyl group is introduced into a side chain as the component (B) can also be used. The addition acrylate polymer can be obtained by using the (meth) acrylate described in the (meth) acrylate copolymer of the above component (A) and the one having a crosslinkable functional group in the molecule. The copolymer of the body is obtained by reacting a compound having a group having a (meth) acrylonitrile group and a crosslinkable functional group in a crosslinkable functional group of the copolymer. The weight average molecular weight of the addition acrylate polymer is usually from 500,000 to 2,000,000 in terms of polystyrene.

In the present invention, one of the above-mentioned polyfunctional acrylate-based monomer, acrylate-based oligomer, and addition acrylate-based polymer as the component (B) is appropriately selected, or two or more kinds are used in combination.

In the present invention, the content ratio of the acrylic copolymer of the component (A) to the active energy ray-curable compound of the component (B) is 100 in terms of the performance of the pressure-sensitive adhesive layer obtained. It is preferably from 1 to 100:100, more preferably from 100:5 to 100:50, and most preferably from 100:10 to 100:40.

[light diffusing agent]

The light diffusing agent contained in the light-diffusing pressure-sensitive adhesive layer may be a fine particle having a refractive index different from that of the adhesive resin constituting the pressure-sensitive adhesive layer, and may be a fine particle formed of an inorganic compound or an organic compound (polymerized). Microparticles formed by the object. The difference in refractive index between the adhesive resin and the light diffusing agent is usually 0.01 or more. When considering the brightness or visibility in the case of an image display device, it is preferably 0.01 or more and 0.5 or less. In consideration of this point, since the refractive index of the adhesive resin is usually about 1.4, the fine particles formed of the inorganic compound or the organic compound used as the light diffusing agent are preferably as follows.

Fine particles formed of an inorganic compound, for example, alumina (refractive index: 1.76), cerium oxide (refractive index: 1.45), and the like.

Microparticles formed from organic compounds, such as melamine beads (refractive index 1.57), polymethylmethacrylate beads (refractive index 1.49), methyl methacrylate/styrene copolymer resin beads (refractive index 1.50 to 1.59) , polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1.46), epoxy resin beads (refractive index 1.5 to 1.6) ), polyoxyalkylene resin beads (refractive index 1.46), and the like.

In addition, when the acrylic copolymer is selected as the component (A) of the adhesive resin, the epoxy resin beads, the polymethyl methacrylate beads, and the polyoxyalkylene resin beads are excellent in dispersibility with respect to the acrylic copolymer. When uniform and good light diffusibility is obtained, it is preferable as a light diffusing agent. Further, as the light diffusing agent, it is preferred that the light is uniformly diffused in a spherical shape and monodisperse.

The average particle diameter of the light diffusing agent is in the range of 0.1 to 20 μm. When the average particle diameter is less than 0.1 μm, the light diffusibility as a light-diffusing pressure-sensitive adhesive layer is lowered, and when the image display device is used, it is impossible to achieve the effect of the present invention without a brightness spot and uniform brightness. . Further, when the average particle diameter is larger than 20 μm, the contrast of the image is adversely affected, and when the image pitch of the display device is larger, unevenness may occur. In view of the above, the average particle diameter of the light diffusing agent is preferably in the range of 0.5 to 10 μm, more preferably in the range of 1 to 7 μm. Further, the average particle diameter of the light diffusing agent herein is a value measured by a centrifugal precipitation light transmission method.

The amount of the light diffusing agent to be used is appropriately determined in consideration of the haze value necessary for each of the light diffusing pressure-sensitive adhesive layers to be blended, or the brightness of the image display device using the same, and generally, the pressure is formed. The adhesive resin of the adhesive layer is preferably in the range of 1 to 40% by mass, more preferably in the range of 3 to 30% by mass. When the content is 1% by mass or more, the effect of the present invention to obtain a uniform brightness can be achieved, and when the content of the fine particles is 40% by mass or less, the adhesion to the adherend is not required to be reduced. value.

Further, in the adhesive material of the present invention, a crosslinking agent as the component (C) may be contained as needed. The crosslinking agent is not particularly limited, and may be appropriately selected from conventional acrylic-based adhesive resins as a user of a crosslinking agent. The crosslinking agent is, for example, a polyisocyanurate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, an acridine compound, a metal chelate compound, a metal alkoxide, A metal salt or the like is preferably used in the case of using a polyisocyanate compound.

Here, the polyisocyanate compound is an aromatic polyisocyanate such as toluene diisocyanate, diphenylmethane diisocyanate or benzodimethyl diisocyanate, or an aliphatic polyisocyanate such as hexamethylene diisocyanate or isophorone. An alicyclic polyisocyanate such as isocyanate or hydrogenated diphenylmethane diisocyanate, and the like of such a biuret, isomeric isocyanate and ethylene glycol, propylene glycol, neopentyl glycol, and trishydroxyl An adduct of a reactant of a compound containing a low molecular weight active hydrogen such as propane or castor oil.

In the present invention, the crosslinking agent may be used alone or in combination of two or more. In addition, the amount of the crosslinking agent is usually from 0.01 to 20 parts by mass, preferably from 0.1 to 10 parts by mass, per 100 parts by mass of the acrylic copolymer of the component (A).

Further, in the adhesive material of the present invention, a decane coupling agent which may contain the component (D) may be used as needed. When the decane coupling agent is contained, for example, when it is bonded to a liquid crystal glass unit cell or the like, the adhesion between the pressure-sensitive adhesive layer and the glass unit cell is better. The decane coupling agent is an organic ruthenium compound having at least one alkoxycarbenyl group in a molecule, and has good compatibility with a pressure-sensitive adhesive component and has light transparency. For example, it is substantially transparent. should. The amount of the decane coupling agent to be added is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 5 parts by mass, per 100 parts by mass of the acrylic copolymer of the component (A).

Specific examples of the above decane coupling agent, such as vinyl trimethoxy decane, vinyl triethoxy decane, 3-methyl propylene oxy propyl trimethoxy decane, etc., containing a polymerizable unsaturated group, 3- An anthracene compound having an epoxy group structure such as glycidoxypropyltrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-aminopropyltrimethoxy Baseline, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, etc. The amine group-containing oxime compound, 3-chloropropyltrimethoxydecane, and the like. These may be used alone or in combination of two or more.

In the adhesive material of the present invention, various additives generally used in the acrylic adhesive resin, such as a binder, an antioxidant, and an ultraviolet absorber, may be added as needed within the range which does not impair the object of the present invention. , light stabilizers, softeners, etc.

The light-diffusing elastic pressure-sensitive adhesive layer of the present invention is preferably formed by irradiating an active energy ray to an adhesive material containing the component (B) as an adhesive resin. By performing the cross-linking treatment using the active energy ray, the entire pressure-sensitive adhesive layer is not deformed, and homogeneous cross-linking can be performed, and the storage elastic modulus of the present invention can be preferably obtained.

Active energy rays such as ultraviolet rays or electron wires. The ultraviolet rays may be obtained by a high pressure mercury lamp, an electrodeless lamp, a xenon lamp, or the like, and the electron wires may be obtained by an electron beam accelerator or the like. Among the active energy rays, ultraviolet rays are more preferable. Further, when an electron beam is used, a light-diffusing sexy pressure-sensitive adhesive can be formed without adding a photopolymerization initiator.

In the adhesive material, the amount of irradiation of the active energy ray is appropriately selected under the binder which can obtain the storage elastic modulus described in detail below and has an adhesive force to the alkali-free glass, and the illuminance is 50 ～ when the ultraviolet ray is ultraviolet ray. 1000 mW/cm ² , the amount of light is 50 to 1000 mJ/cm ² , and it is preferably in the range of 10 to 1000 krad for the electron beam.

In combination with the light diffusing pressure-sensitive adhesive layer of the light diffusing agent, the brightness of the image display device used in the composite polarizing plate can be ensured, and the haze value of the display image is not easily generated or blurred. It is preferably 5% or more, more preferably 20 to 90%, and most preferably 30 to 75%. The haze value is a value indicated by JIS K7105 at (diffusion transmittance/total light transmittance) × 100 (%).

Further, in the light diffusing pressure-sensitive adhesive layer of the present invention, the gel fraction is preferably 60% or more. In other words, when the amount of the low molecular weight component extracted by the organic solvent is small, the material is floated or peeled off under heating or under warm conditions, and the contamination to the adherend is small, and the gel fraction is 60% or more. The pressure-adhesive layer has high durability or stability. The gel fraction is more preferably 85% or more, and most preferably 90 to 99.9%. In the present invention, a composite polarizing plate having the light-diffusing pressure-sensitive adhesive layer is used, for example, an image display device fabricated by bonding to a liquid crystal glass cell, which is less likely to cause light leakage even in a high-temperature and high-humidity environment. It is excellent in that it can highly control the blur or extravasation of the displayed image. Further, the method for measuring the gel fraction is described in detail below.

The light-diffusing pressure-sensitive adhesive layer used in the present invention preferably has an adhesive force of 0.2 N/25 mm or more for the alkali-free glass. When the adhesive force is 0.2 N/25 mm or more, for example, an optically functional film such as a polarizing plate can be bonded to a liquid crystal glass cell with a sufficient adhesive force. A better adhesion is 1.0 to 50 N/25 mm.

Further, the adhesion to polycarbonate is preferably 5 N/25 mm or more. When the adhesive force is 5 N/25 mm or more, for example, the polarizing plate can be bonded to the phase difference plate with a sufficient adhesive force. Further, the method for measuring the above-described adhesive force will be described in detail below.

The light-diffusing pressure-sensitive adhesive layer used in the present invention preferably has a peeling force of 70 μm or less after a holding force at 80 ° C of 200 μm or less. When the amount of the peeling is 200 μm or less, when an optical functional film such as a polarizing plate is bonded to, for example, a liquid crystal glass cell, a good bonding state can be maintained over a long period of time. The amount of peeling is preferably 100 μm or less. Further, the method for measuring the above-mentioned peeling amount (holding force) will be described in detail below.

The thickness of the light-diffusing pressure-sensitive adhesive layer to which the light-diffusing agent is blended is determined depending on the adhesion, etc., and is usually in the range of 1 to 40 μm. In order to form the thin composite polarizing plate for the purpose of the present invention, it is preferable to apply it thinly without damaging properties such as workability and durability. Therefore, the thickness of the light-diffusing sexy pressure-sensitive adhesive layer is 3 to 25 μm, so that good workability, high durability, and brightness and display image when the image display device is viewed from the front or from the inclined surface can be maintained. It is preferable that it is not easy to cause extravasation or blurring.

[Storage Elasticity Rate of Light-Diffusing Sexy Pressure-Adhesive Layer]

Further, in the present invention, the light-diffusing sexy pressure-sensitive adhesive layer containing a light-diffusing agent exhibits a storage modulus of 0.15 to 10 MPa at 23 ° C, preferably 0.15 to 10 MPa at 23 ° C and 80 ° C. More preferably, it exhibits a storage modulus of 0.4 to 3 MPa at 23 ° C and 80 ° C. Further, the storage modulus of the pressure-sensitive adhesive layer was measured based on JIS K7244. The pressure-sensitive adhesive layer used in a general image display device or an optical film used therein has a storage modulus of up to about 0.1 MPa at 23 ° C, compared to the pressure-sensitive adhesive layer specified in the present invention. The storage modulus is a high value of 0.15 to 10 MPa. The high storage modulus can be supplemented by using a hard pressure-sensitive adhesive layer, when placed in a high-temperature environment, or when the high-temperature environment and the low-temperature environment are repeated, the cohesive force is insufficient, and the generated photon can be accompanied. Shrinkage, suppressing dimensional changes to small values. In other words, good durability can be obtained. Further, the adhesive strength at a storage elastic modulus of 23 MPa or less at 23 ° C is preferable in the present invention.

In the present invention, the storage elastic modulus of the light-diffusing sexy pressure-sensitive adhesive layer containing the light-diffusing agent is maintained at a high value as described above, and when the high storage elastic modulus is formed, the adhesive resin of the substrate exhibits high storage elasticity. The composition of the rate. The method of setting the storage elastic modulus of the light-diffusing pressure-sensitive adhesive layer to such a high value is not particularly limited, and for example, the (A) acrylic copolymer and the (B) active energy ray-curable compound are used as the adhesive resin. It is preferable that the formed adhesive material is hardened by irradiation with an energy ray, since it exhibits a high storage modulus.

Further, the first pressure-sensitive adhesive layer 6 which bonds the polarizer 1 and the phase difference plate 5 or 4 is not limited by the presence or absence of the light diffusing agent, and is preferably 0.15 to 10 MPa at 23 ° C, preferably. It is composed of a storage elastic modulus of 0.15 to 10 MPa at 23 ° C and 80 ° C. However, when the storage elastic modulus is high without a light diffusing agent, the same method as described above can be employed.

[Formation of Pressure Sensitive Adhesive Layer and Fabrication of Composite Polarizing Plate]

A method of forming a pressure-sensitive adhesive layer or a light-diffusing sexy pressure-sensitive adhesive layer on the surface of the polarizer 1 or the surface of the phase difference plate 5 or 4 is not particularly limited, and for example, the adhesive material may be dissolved or dispersed in toluene. Or a solution of 10 to 40% by weight in an organic solvent such as ethyl acetate, and applying the solution directly to the surface of the polarizing or phase difference plate forming the pressure-sensitive adhesive layer, and drying the layer, and then laminating a method of peeling off a film formed by a resin film treated with a release agent such as a polyoxyalkylene system, or after forming a pressure-sensitive adhesive layer on the release film as described above, and transferring it to a polarizer or a phase difference plate Method etc. In addition, when a pressure-sensitive adhesive layer is formed on the surface of the polarizer or the phase difference plate, it is required to form a surface of the pressure-sensitive adhesive layer of the polarizer or the phase difference plate, and is attached to the pressure-sensitive adhesive layer. In the surface of the polarizer or the retardation plate, one or both of them may be subjected to a treatment for improving the adhesion, for example, a corona discharge treatment or the like.

As shown in Fig. 1, the transparent protective layer 2 is disposed on one surface of the polarizer 1, and the phase difference plate 5 is laminated on the other surface of the polarizer 1 via the first pressure-sensitive adhesive layer 6, and then When the second pressure-sensitive adhesive layer 7 is disposed on the outer side of the phase difference plate 5, the transparent protective layer 2 is bonded to one surface of the polarizer 1, and the first pressure-sensitive adhesive layer 6 is provided on the other surface of the polarizer 1. a polarizing plate with a pressure-sensitive adhesive, or a phase difference plate with a pressure-sensitive adhesive layer provided on one surface of the phase difference plate 5 with a second pressure-sensitive adhesive layer 7 and overlapping the first feeling It is advantageous to laminate the pressure-bonding layer 6 and the phase difference plate 5 underneath. Further, for example, a phase difference plate provided with a two-sided pressure-sensitive adhesive layer provided with a first pressure-sensitive adhesive layer 6 and a second pressure-sensitive adhesive layer 7 may be used on both surfaces of the phase difference plate 5, and the object may be made The polarizing plate to which the transparent protective layer 2 is bonded to one surface of the polarizer 1 is laminated under the first pressure-sensitive adhesive layer 6 and the polarizer 1.

As shown in FIG. 2, the transparent protective layer 2 is disposed on one surface of the polarizer 1, and the first phase difference plate 4 and the third layer are sequentially laminated on the other surface of the polarizer 1 via the first pressure-sensitive adhesive layer 6. When the pressure-sensitive adhesive layer 8, the second phase difference plate 5, and the second pressure-sensitive adhesive layer 7 are bonded, the transparent protective layer 2 is bonded to one surface of the polarizer 1 and the first surface of the polarizer 1 is placed. a polarizing plate with a pressure sensitive adhesive attached to the pressure sensitive adhesive layer 6 or a phase with a first pressure sensitive adhesive layer 8 disposed on one surface of the first phase difference plate 4 with a first pressure sensitive adhesive a differential plate and a phase difference plate with a second pressure-sensitive adhesive layer 7 on the one surface of the second phase difference plate 5 with the second pressure-sensitive adhesive layer 7 so as to overlap the first pressure-sensitive adhesive layer 6 in this order It is advantageous to laminate the first phase difference plate 4 or to overlap the third pressure-sensitive adhesive layer 8 and the second phase difference plate 5, respectively. Further, for example, a polarizing plate with a pressure-sensitive adhesive layer provided with a transparent protective layer 2 on one surface of the polarizer 1 and a first pressure-sensitive adhesive layer 6 on the other surface of the polarizer 1 may be used, or A phase difference plate with a double-sided pressure-sensitive adhesive attached to the third pressure-sensitive adhesive layer 8 and the second pressure-sensitive adhesive layer 7 on both sides of the second phase difference plate 5 is provided with a pressure-sensitive adhesive Any method of laminating the first pressure-sensitive adhesive layer 8 between the first pressure-sensitive adhesive layer 6 and the third pressure-sensitive adhesive layer 8 of the two-phase pressure-sensitive adhesive layer .

The method of laminating the polarizer and the phase difference plate is not particularly limited and may be laminated by a conventional technique. For example, a method of laminating the retardation axes of the phase difference plates perpendicularly or in parallel with respect to the polarization transmission axis of the polarizers using a bonding roller or the like, or a phase difference plate for the polarization transmission axis of the polarizers is used. The method of laminating the slow phase axes at a given angle. In particular, the composite polarizing plate of the present invention is effective in laminating a polarizing transmission axis of a polarizer and a retardation axis of a phase difference plate at a predetermined angle to form a circularly polarized or elliptically polarized type.

[Laminated optical member]

Further, in the composite polarizing plate of the present invention, one or two or more optical layers having other optical functions may be laminated to form a laminated optical member. Examples of other optical layers include a reflective layer and a semi-transmissive reflection, in addition to a surface treatment layer of a hard coating layer, an antireflection layer, an antiglare layer, and the like exemplified as a layer which can be previously disposed on the surface of the transparent protective layer 2. Layer, diffusion layer, film for improving brightness, light collecting plate, and the like.

The reflective composite polarizing plate is used for a liquid crystal display device in which incident light from the viewing side is reflected and displayed. Since the light source such as a backlight can be omitted, the liquid crystal display device can be easily made thinner. Further, the transflective composite polarizing plate is a transmissive display type liquid crystal display device which is a reflective type in a bright place and a light source such as a backlight in a dark place. The reflective layer for forming the reflective composite polarizing plate can be formed, for example, by a foil or a vapor deposited film formed of a metal such as aluminum on the transparent protective layer 2 on the polarizer 1. Further, the semi-transmissive reflective layer for forming the semi-transmissive reflective composite polarizing plate can be bonded to the transparent protective layer by a method in which the reflective layer is used as a half mirror or a reflective plate containing a pearl pigment or the like having light transparency. The method of 2 is formed. Further, the diffused composite polarizing plate has a function of diffusing incident light, and for example, a method of performing buffering treatment on the transparent protective layer 2, a method of applying a resin containing fine particles, a method of bonding a film containing fine particles, and the like. In various methods, a light diffusion layer having a fine uneven structure is formed on the surface.

In addition, the composite polarizing plate for reflection and diffusion is provided with a diffused reflection layer by, for example, providing a reflective layer reflecting the uneven structure on the fine uneven structure surface of the diffusion type composite polarizing plate. The reflective layer of the fine concavo-convex structure has the advantage of diffusing the incident light, preventing directivity or misalignment, and suppressing light and dark spots. Further, the resin layer or film containing fine particles has the advantage of diffusing the incident light and the reflected light while passing through the layer, and more control of light and dark spots. The reflective layer which reflects the fine concavo-convex structure on the surface can be directly attached to the surface of the fine concavo-convex structure by a method such as vacuum deposition, ion thin layer coating, sputtering or the like, or plating. Formed on it. Further, in order to form fine particles to be incorporated in the surface fine concavo-convex structure, for example, ceria, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, or cerium oxide having an average particle diameter of 0.1 to 30 μm can be used. The inorganic fine particles formed, the organic fine particles formed by crosslinking or uncrosslinked polymers, and the like.

The film which improves the brightness is a function which transmits a part of incident natural light as a linear polarizing or a circularly polarized light, and reproduces and reuses the residual, and is used for the purpose of improving brightness in a liquid crystal display device, etc.. For example, laminating a plurality of films having different anisotropy of refractive index to produce a reflective linear polarizing separation sheet designed to reflect the opposite polarity, an alignment film of a cholesteric liquid crystal polymer, or supporting an alignment liquid crystal on the substrate film. A layer of reflective circular polarizing separation sheet or the like.

The light collecting plate is used for the purpose of controlling the optical path or the like, and may be formed by arranging a sheet or a lens row sheet or a sheet of a dot.

Some of the above various optical layers are directly disposed on the surface of the transparent protective layer 2 by coating, evaporation, or the like. Further, the optical layer used in the form of a film can be integrated with a composite polarizing plate using a binder or a pressure-sensitive adhesive. Therefore, the adhesive or pressure-sensitive adhesive to be used is not particularly limited, and may be appropriately selected. It is preferable to use a pressure sensitive adhesive in terms of the ease of adhesion or prevention of optical deformation. Examples of the pressure-sensitive adhesive are formed of a base polymer such as an acrylic, rubber, urethane, polyoxyalkylene or polyvinyl ether. Specifically, it is first used in the same manner as those exemplified by the user in the pressure-sensitive adhesive layers 6, 7, 8. Among them, a pressure-sensitive adhesive having an acrylic base polymer (adhesive resin) is selected to have excellent optical transparency, to maintain proper wettability or cohesive force, to have excellent adhesion to a substrate, and to have weather resistance or It is preferable that heat resistance or the like does not cause peeling problems such as floating or peeling under heating or humidification conditions.

[Image display device]

The composite polarizing plate or laminated optical member of the present invention can be combined with various image display elements to form an image display device. For example, it may be disposed on one or both sides of the liquid crystal cell to form a liquid crystal display device. The liquid crystal cell to be used may be any, and for example, a liquid crystal cell such as an active matrix-driven type which is typically a thin film transistor type or a simple body-driven type which is typically a super twisted nematic type may be used to form a liquid crystal. Display device. When the composite polarizing plate or the laminated optical member of the present invention is provided on both sides of the liquid crystal cell, the same may be disposed on both surfaces, or may be different.

Fig. 3 is a typical cross-sectional view showing an example in which the composite polarizing plate and the laminated optical member of the present invention are used in a liquid crystal display device. In this example, the state in which the release film 9 is peeled off by the composite polarizing plate 11 illustrated in FIG. 1 is attached to one surface of the liquid crystal cell 30 (upper side in the drawing) on the side of the second pressure-sensitive adhesive layer 7 . Then, the second pressure-sensitive adhesive layer 7/phase difference plate 5/first pressure-sensitive adhesive layer 6/polarizer 1/transparent protection is sequentially laminated on the other surface (lower side in the drawing) of the liquid crystal cell 20. The layer 2 (this state corresponds to the composite polarizing plate 11 shown in FIG. 1), and the laminated optical member 20 of the other optical layer 18 is laminated on the outer side thereof, and is bonded to the second pressure-sensitive adhesive layer 7 side. . In the liquid crystal display device of this example, the upper side of the figure is the viewing side, and when the backlight is arranged, the backlight is provided on the lower side of the figure. The other optical layer 18 at this time may be a reflective layer, a semi-transmissive reflective layer, a film for improving brightness, a light collecting plate, or the like. Fig. 3 is an example of the composite composite polarizing plate and the liquid crystal cell 30 shown in Fig. 1, and the composite composite polarizing plate 12 and the liquid crystal cell shown in Fig. 2 are formed into a liquid crystal display device. The composite polarizing plate 11 is replaced with the composite polarizing plate 12 shown in Fig. 2, which can be understood from the above description.

Further, the composite polarizing plate of the present invention is also effective in a circular display or an elliptically polarized type having an anti-reflection function in an image display device other than a liquid crystal display device, for example, a flat display device such as an organic EL display device. Of course, an image display device using the composite polarizing plate or laminated optical member of the present invention is not limited by these examples.

In the following, the present invention is more specifically described by way of examples and comparative examples, but the invention is not limited by the examples. Further, in the following examples, the phase difference value was measured at a wavelength of 589 nm, and the storage elastic modulus, the adhesive force, the haze value, the gel fraction, the holding power, and the evaluation of the composite polarizing plate were measured by the following methods. , average particle size, and weight average molecular weight.

[Examples]

(1) Method for measuring storage modulus

The storage elastic modulus (G') of the pressure-sensitive adhesive layer is based on JIS K7244, and a column of 8 mm Φ × 1 mm thick is used as a test piece, and a measuring instrument "DYNAMIC ANALYZERRDA II" manufactured by REOMETRIC Co., Ltd. is used at 23 ° C and 80 ° C. Under the condition, the force shear method with a cycle number of 1 Hz is obtained.

(2) Adhesion (adhesion to alkali-free glass and polycarbonate)

Two samples of 25 mm wide and 100 mm long were cut out from the composite polarizing plate 13, and the peeling release film 9 (thickness of the light-diffusing pressure-sensitive adhesive layer of 25 μm) was attached to the alkali-free glass [Knin Valley] "1737"] or a polycarbonate resin sheet [Biayes (transliteration) C110-100 (trade name)" manufactured by Teijin Chemicals Co., Ltd.), at a pressure cooker manufactured by Kurihara Plant, at 0.5 MPa, 50 ° C, 20 The conditions of the minute are subjected to a pressurization treatment. Then, after standing for 24 hours in an environment of 23° C. and a relative humidity of 50%, a tensile tester (a tenter manufactured by Oriente Valley Co., Ltd.) was used in the same environment at a peeling speed of 300 mm/min. The value measured by the peeling angle of 180° was measured as the adhesive force.

(3) Haze value

The release film on the light-diffusing pressure-sensitive adhesive layer (separately) was peeled off, and the diffused transmittance was measured using a cumulative spherical light transmittance measuring device ("NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd.) based on JIS K7105. (Hd%) and total light transmittance (Ht%) were obtained by the following formula.

Haze value (%) = Hd / Ht × 100

(4) Gel fraction

The light-diffusing pressure-sensitive adhesive layer (separately) having a thickness of 25 μm was sampled into a size of 80 mm × 80 mm, and the release film was peeled off and removed, and then weighed only on a polyester mesh (screen size 200) with a precision scale. The light diffuses the weight of the sexy pressure-bonding layer. The weight at this time is M1. The light-diffusing/pressure-sensitive adhesive layer was immersed in ethyl acetate using an adsorber (extractor), and subjected to reflux treatment for 16 hours. Then, the light-diffusing sexy pressure-sensitive adhesive layer was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C and a relative humidity of 50%, and dried in an oven at 80 ° C for 12 hours. The weight of the light-diffusing sexy pressure-sensitive adhesive layer after drying is weighed only by the precision balance, and the weight is M2. The value indicated by (M2/M1) × 100% is the gel fraction.

(5) Retention

A sample of 25 mm width and 150 mm length was cut out from the composite polarizing plate, and the peeling film was peeled off, and after attaching to the test plate and attached to 25 mm × 25 mm (area), a roll of 2 kg was reciprocated at a speed of 300 mm/min on the sample. The composite polarizing plate was melted on the test plate. Then, it was left to stand in an environment of 23 ° C and a relative humidity of 50% for 2 hours, and the load was measured by using a holding force measuring device described in JP-A-11-23449, and the load was measured at 80 ° C for 70000 seconds. the amount. In the test plate, the SUS-304 steel sheet having a thickness of 1.5 to 2.0 mm as defined in JIS-G-4305 was uniformly polished in the longitudinal direction using the water-resistant abrasive paper No. 360 prescribed in JIS-R-6253. Further, the measurement sensor of the retention force measuring device is a data indicator ("DEGIMATIC INDICATOR" manufactured by Metzington Co., Ltd.).

(6) Evaluation of composite polarizer

The composite polarizing plate was adjusted to a size of 233 mm × 309 mm by a cutting device ("Super-cutting machine" "PN1-600" manufactured by Takino Seiki Co., Ltd.), and bonded to an alkali-free glass [1737" manufactured by Knin Valley. Thereafter, the pressure cooker manufactured by Kurihara Seisakusho Co., Ltd. was subjected to pressure treatment at 0.5 MPa, 50 ° C, and 20 minutes. Then, it was put in the environment of each of the durability conditions described below, and after 200 hours, observation was performed using a 10-magnification microscope, and the durability was evaluated based on the following criteria.

◎: On the four sides, there is no disadvantage in the range from the outer peripheral end to the range of 0.3 mm or more.

○: There were no disadvantages in the range from the outer peripheral end to the 0.6 mm or more on the four sides.

×: On either side of the four sides, there is an abnormality in the appearance of the composite polarizing plate of 0.1 mm or more which is floating, peeling, bubbling, streaking or the like from the outer peripheral end portion to the range of 0.6 mm or more.

<endurance condition>

80 ° C, 90 ° C, 60 ° C ‧ relative humidity 90% environment,

-40 ° C 30 minute thermal shock test at 85 ° C, 50 cycles

(7) Determination of average particle size

A sample obtained by sufficiently stirring a liquid of 1.2 g of a light-diffusing agent and 98.8 g of isopropyl alcohol was used as a sample for measurement, and a centrifugal automatic particle size distribution measuring apparatus ("CAPA-700" manufactured by Horiba, Ltd.) was used to precipitate light by centrifugation. The measurement is carried out by the method.

(8) Determination of weight average molecular weight

The weight average molecular weight is a polystyrene equivalent value measured by gel permeation chromatography (GPC) under the following conditions.

GPC measuring device: HTC-8020 manufactured by Tosoh Corporation

GPC column (passed in the following order): Dongsuo (stock) system

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

Determination of solvent: tetrahydrofuran

Measuring temperature: 40 ° C

Further, in the following examples, the following were used as the pressure-sensitive adhesive layer.

Pressure-sensitive adhesive layer A: an urethane acrylate oligomer is blended in a copolymer of butyl acrylate and acrylic acid, and an organic solvent solution to which an isocyanate crosslinking agent is added is applied to a release treatment A sheet-like adhesive formed on a release-treated surface of a polyethylene terephthalate film (release film) having a thickness of 38 μm and dried to a thickness of 25 μm.

The storage modulus of the pressure-sensitive adhesive layer A was 0.41 MPa at 23 ° C and 0.22 MPa at 80 ° C.

Light-diffusing pressure-sensitive adhesive layer A: a polysiloxane catalyst particle having an average particle diameter of 4.5 μm is applied to an organic solvent solution having the same composition as that of the pressure-sensitive adhesive layer A, and is applied to a thickness subjected to mold release treatment. The release-treated surface of a 38 μm polyethylene terephthalate film (release film) was dried to form a sheet-like adhesive having a thickness of 25 μm. The storage elastic modulus of the light-diffusing sexy pressure-sensitive adhesive layer A was 0.41 MPa at 23 ° C and 0.22 MPa at 80 ° C. Moreover, the haze value is 45%.

Pressure-sensitive adhesive layer B containing a light diffusing agent: a release-treated surface of a 38 μm-thick polyethylene terephthalate film (release film) having a release treatment, and a light-diffusing pressure-sensitive adhesive A commercially available sheet-like binder of an acrylic pressure-sensitive adhesive layer formed by a thickness of 25 μm, which is the same polysiloxane catalyst particle as A. No urethane acrylate oligomer was blended. A pressure-sensitive adhesive layer containing a light diffusing agent (referred to as a pressure-sensitive adhesive layer that does not satisfy the requirements of the present invention containing a light diffusing agent. The same applies hereinafter) B storage elastic modulus, 0.05 MPa at 23 ° C, at 80 It is 0.04 MPa at °C. Moreover, the haze value is 45%.

[Example 1]

(a) Polarizer with pressure-sensitive adhesive layer

Transparent protection formed by laminating a film of a triacetyl phthalocyanine film having a thickness of 40 μm via an epoxy-based adhesive on one side of a polarizer formed by adsorbing a film having iodine and having a thickness of 25 μm in polyvinyl alcohol Layer of polarizing plate. The pressure-sensitive adhesive layer A was bonded to the polarizer side, and a polarizing plate having a pressure-sensitive adhesive layer having a transparent protective layer/polarizer/pressure-sensitive adhesive layer A/release film was prepared.

(b) Phase difference plate with pressure-sensitive adhesive layer

A phase difference plate ("Yessina film" manufactured by Sekisui Chemical Industry Co., Ltd.) having a thickness of 40 μm and an in-plane retardation of 140 nm was formed using an extended film of the original spinel-based resin. On one surface of the λ/4 plate, the light-diffusing pressure-sensitive adhesive layer A was bonded to each other to form a phase difference plate with a pressure-sensitive adhesive layer.

(c) Production of composite polarizer

After peeling off the release film by the polarizing plate with the pressure-sensitive adhesive layer prepared in the above (a), the phase of the pressure-sensitive adhesive layer prepared by the above (b) is applied to the pressure-sensitive adhesive layer side. The phase difference plate side of the difference plate (the side where the light diffusion type pressure-sensitive adhesive layer is not provided) is bonded to the retardation axis of the phase difference plate at 45° to the polarization transmission axis of the polarizing plate to produce a composite polarizing plate. . Fig. 4 is a typical cross-sectional view showing the layer constitution of the composite polarizing plate produced herein. In other words, the composite polarizing plate 13 produced in this example has the following layer configuration.

Transparent protective layer 2 / polarizer 1 / first pressure-sensitive adhesive layer 6 (25 μm) / phase difference plate (λ / 4 plate) 5 / second pressure-sensitive adhesive layer 7a (light diffusion sexy pressure adhesive layer, 25 μm ) / peeling film 9 .

Further, it can be understood from Fig. 4 that the sequential lamination shows that a distance is formed between the pressure-sensitive adhesive layer 6 and the λ/4 plate 5, and these are substantially intimate contact, which can be understood from the above description. The fifth and sixth drawings below show the distance between the pressure-sensitive adhesive layer and the phase difference plate bonded thereto, and have the same meaning as in Fig. 4.

(d) Evaluation of composite polarizers

The release film 9 was peeled off from the composite polarizing plate 13 obtained in the above (c), and the exposed light-diffusing pressure-sensitive adhesive layer 7a was attached to a glass plate, and subjected to a hot pot treatment at 0.5 MPa and 50 ° C for 20 minutes. The composite polarizing plate is adhered to the glass plate. In this state, it was allowed to stand in an environment of -40 ° C for 30 minutes, and then placed in an environment of +85 ° C for 30 minutes as a single cycle, and the cycle was repeated 50 times for a thermal shock test. When the composite polarizing plate after the test was observed, no defects were generated and maintained in a good state.

[Embodiment 2]

(a) Polarizer with pressure-sensitive adhesive layer

In the same manner as in (a) of Example 1, a polarizing plate having a pressure-sensitive adhesive layer having a transparent protective layer/photo-polarizer/pressure-sensitive adhesive layer A/release film was prepared.

(b) Phase difference plate with pressure-sensitive adhesive layer

A phase difference plate having an in-plane phase difference of 270 nm with a λ/2 plate and a phase difference plate having a thickness of 33 μm, which is formed by an extended film of a raw spinel-based resin, is used. a phase difference plate (λ/2 plate) of a pressure-sensitive adhesive layer of an acrylic pressure-sensitive adhesive having a thickness of 15 μm on one side of a "Yessina film" (λ/2 plate) ). In addition, an in-plane retardation plate having a thickness of λ/4 of 90 nm formed by a stretched film of a raw spinel-based resin and having a thickness of 28 nm (the water-storage chemical industry) On one surface of the Jessina film ") (λ/4 plate), the light-diffusing pressure-sensitive adhesive layer A was bonded to each other to form a phase difference plate (λ/4 plate) with a pressure-sensitive adhesive layer.

(c) Production of composite polarizer

After peeling off the release film by the polarizing plate formed of the polarizing plate with the pressure-sensitive adhesive layer produced in the above (a), the pressure-sensitive adhesive produced by the above (b) is applied to the pressure-sensitive adhesive layer side. λ/2 plate side of the phase difference plate (λ/2 plate) of the adhesive layer (the side where the pressure-sensitive adhesive layer is not provided), and the retardation axis of the λ/2 plate is opposite to the polarization transmission axis of the polarizing plate The film was bonded at 15°, and the phase difference plate (λ/4 plate) with the pressure-sensitive adhesive layer prepared in the above (b) was placed on the side of the pressure-sensitive adhesive layer as the λ/4 plate side. (the side of the photo-diffusion-type pressure-sensitive adhesive layer is not provided), and the retardation axis of the λ/4 plate is 60° with respect to the slow phase axis of the λ/2 plate (for the polarization transmission axis of the polarizing plate) 75°) fit to make a composite polarizer. Fig. 5 is a schematic cross-sectional view showing the layer constitution of the composite polarizing plate produced herein. In other words, the composite polarizing plate 14 produced in this example has the following layer configuration.

Transparent protective layer 2 / polarizer 1 / first pressure-sensitive adhesive layer 6 (25 μm) / phase difference plate (λ / 2 plate) 4 / third pressure-sensitive adhesive layer 8 (15 μm) / phase difference plate (λ / 4 plate) 5/second pressure-sensitive adhesive layer 7a (light-diffusing pressure-sensitive adhesive layer, 25 μm) / release film 9.

(d) Evaluation of composite polarizers

The same thermal shock test as in (d) of Example 1 was carried out from the composite polarizing plate obtained in the above (c). When the composite polarizing plate after the test was observed, no defects were generated and maintained in a good state.

[Example 3]

(a) Polarizer with pressure-sensitive adhesive layer

In the same manner as in (a) of Example 1, a polarizing plate having a pressure-sensitive adhesive layer having a transparent protective layer/photo-polarizer/pressure-sensitive adhesive layer A/release film was prepared.

(b) Phase difference plate with pressure-sensitive adhesive layer

A phase difference plate having an in-plane phase difference of 270 nm with a λ/2 plate and a phase difference plate having a thickness of 33 μm, which is formed by an extended film of a raw spinel-based resin, is used. On one side of the "Yessina film" (λ/2 plate), the above-mentioned light-diffusing pressure-sensitive adhesive layer A is laminated to form a phase difference plate (λ/ with a pressure-sensitive adhesive layer). 2 boards). In addition, an in-plane retardation plate (the "Yessina film" of the Sekisui Chemical Industry Co., Ltd.) which is formed of an extended film of the original spinnylene resin and has a wavelength of λ/4 of λ of light λ (λ) On one side of the /4 plate, a phase difference plate (λ/4 plate) with a pressure-sensitive adhesive layer laminated with an acrylic pressure-sensitive adhesive was laminated to a thickness of 15 μm.

(c) Production of composite polarizer

After peeling off the release film by the polarizing plate formed of the polarizing plate with the pressure-sensitive adhesive layer produced in the above (a), the pressure-sensitive adhesive produced by the above (b) is applied to the pressure-sensitive adhesive layer side. λ/2 plate side of the phase difference plate (λ/2 plate) of the adhesive layer (the side where the light diffusion type pressure-sensitive adhesive layer is not provided), and the polarization axis of the polarizing plate of the retardation axis of the λ/2 plate In the case of bonding at 15°, the phase difference plate (λ/4 plate) with the pressure-sensitive adhesive layer prepared in the above (b) is made on the side of the pressure-sensitive adhesive layer as the λ/4. On the side of the board (the side where the pressure-sensitive adhesive layer is not provided), the retardation axis of the λ/4 plate is 60° with respect to the slow phase axis of the λ/2 plate (for the polarization transmission axis of the polarizing plate) 75°) fit to make a composite polarizer. Fig. 6 is a typical cross-sectional view showing the layer constitution of the composite polarizing plate produced herein. In other words, the composite polarizing plate 15 produced in this example has the following layer configuration.

Transparent protective layer 2 / polarizer 1 / first pressure-sensitive adhesive layer 6 (25 μm) / phase difference plate (λ / 2 plate) 4 / third pressure-sensitive adhesive layer 8a (light scattered elastic pressure adhesive layer, 25 μm) / phase difference plate (λ / 4 plate) 5 / second pressure-sensitive adhesive layer 8 (15 μm) / release film 9.

(d) Evaluation of composite polarizers

The same thermal shock test as in (d) of Example 1 was carried out from the composite polarizing plate obtained in the above (c). When the composite polarizing plate after the test was observed, no defects were generated and maintained in a good state.

[Comparative Example 1]

In the embodiment (b), the light-diffusing pressure-sensitive adhesive layer A bonded to one surface of the λ/4 plate is changed to the pressure-sensitive adhesive layer B containing the light-diffusing agent, and the rest and the examples 1 A composite polarizing plate was produced in the same manner. With respect to the obtained composite polarizing plate, the same thermal shock test as in (d) of Example 1 was carried out. When the composite polarizing plate after the test was observed, bubbles were generated.

[Comparative Example 2]

In the embodiment (b), the light-diffusing pressure-sensitive adhesive layer A bonded to one surface of the λ/4 plate is changed to the pressure-sensitive adhesive layer B containing the light-diffusing agent, and the rest and the examples 2 A composite polarizing plate was produced in the same manner. With respect to the obtained composite polarizing plate, the same thermal shock test as in (d) of Example 1 was carried out. When the composite polarizing plate after the test was observed, bubbles were generated.

[Comparative Example 3]

In (b) of the embodiment 3, the light-diffusing pressure-sensitive adhesive layer A bonded to one surface of the λ/2 plate is changed to the pressure-sensitive adhesive layer B containing the light-diffusing agent, and as a result, λ/2 A composite polarizing plate was produced in the same manner as in Example 3 except that a pressure-sensitive adhesive B containing a light diffusing agent having a small elastic modulus was disposed between the plate and the λ/4 plate. With respect to the obtained composite polarizing plate, the same thermal shock test as in (d) of Example 1 was carried out. When the composite polarizing plate after the test was observed, bubbles were generated.

The main conditions and results of the above Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. Further, in the typical examples of the samples after the thermal shock test of the examples and the comparative examples, the enlarged photograph of the sample of Example 2 viewed from the side of the transparent protective layer of the polarizer is shown in Fig. 8(A), and then, compared. The enlarged photograph of the sample of Example 2 viewed from the side of the transparent protective layer of the polarizer is shown in Fig. 8(B). In the sample of Comparative Example 2 shown in (B), the sample of Example 2 shown in (A) was observed for a plurality of bubbles having an elliptical shape, and no bubbles were generated and maintained. Good condition.

Adhesive material layer C to L containing light diffusing agent:

An ethyl acetate solution (solid content: 14% by mass) of a binder (solid content) of the composition (solid content) shown in Table 2, and a polyethylene terephthalate release film having a thickness of 38 μm was prepared [Ridi Valley (transliteration) The peeling layer of "SP-PET3811" manufactured by the company was applied by a knife coater at a thickness of 25 μm after drying, and then dried at 90 ° C for 1 minute to form a bond containing a light diffusing agent. Material layer C ~ L.

Adhesive material layer C to L without light diffusing agent:

An ethyl acetate solution (solid content: 14% by mass) of an adhesive material formed by removing the composition of the bead from the composition shown in Table 2 (solid content) was prepared, and polyethylene terephthalate having a thickness of 38 μm was prepared. A release film ("SP-PET3811" manufactured by Riddy Co., Ltd.) was applied to a release layer having a thickness of 25 μm after drying, and then dried by a knife coater, and then dried at 90 ° C for 1 minute. The adhesive material layers C to L containing no light diffusing agent are formed.

Light-diffusing sexy pressure-sensitive adhesive layer C-J and pressure-sensitive adhesive layer K-L containing light diffusing agent:

The light-diffusing agent-bonding material layers C to L are irradiated with ultraviolet rays under the following conditions to obtain a light-diffusing pressure-sensitive adhesive layer (separate) C to J and a pressure-sensitive adhesive layer containing a light diffusing agent ( Separate) K ~ L. These pressure-sensitive adhesive layers were obtained by using the values of storage modulus, haze value, and gel fraction of Table 3-1.

<Ultraviolet irradiation conditions>

. Use the electrodeless lamp made by Xiuqiong Co., Ltd. H bulb

. Illuminance 600mW/cm ² , light quantity 150mJ/cm ²

Ultraviolet illuminance. The light meter uses "UVPF-36" manufactured by Aegula Fegus.

(a') a polarizing plate with a layer of an adhesive material containing a light diffusing agent

Transparent protection formed by laminating a film of a thickness of 40 μm of triethylenesulfonated cellulose film via an epoxy-based adhesive on one side of a polarizer formed by adsorbing a film having a thickness of 25 μm with iodine adsorbed in polyvinyl alcohol Layer of polarizing plate. On the side of the polarizer, the above-mentioned adhesive material layer containing the light diffusing agent based on Table 3-1 is bonded to form an adhesive material layer/peeling layer with a transparent protective layer/polarizer/light diffusing agent A polarizing plate of a layer of an adhesive material containing a light diffusing agent composed of a film.

(b') phase difference plate of the adhesive material layer not containing the light diffusing agent

One of the retardation plates ("Yessina film" of Sekisui Chemical Industry Co., Ltd.) (λ/4 plate) formed of a stretched film of the original spinnylene resin and having a phase difference of 140 nm in a plane having a thickness of 40 nm The adhesive material layer containing no light diffusing agent is bonded to the above, and a phase difference plate (λ/4 plate)/adhesive material layer containing no light diffusing agent/release film is formed without light diffusion. The phase difference plate of the adhesive material layer of the agent.

(c') Fabrication of composite polarizer

After peeling off the peeling film from the polarizing plate with the light diffusing agent-containing adhesive material layer prepared in the above (a'), on the side of the light diffusing agent-containing adhesive material layer, the above (b') The phase difference plate side of the phase difference plate with the adhesive material layer containing no light diffusing agent (the side of the adhesive material layer without the light diffusing agent is not provided), and the retardation axis of the phase difference plate The polarizing plate of the polarizing plate is bonded at 45°.

Then, the composite polarizing plates of Examples 4 to 11 and Comparative Examples 4 to 5 of Table 3-2 were produced by irradiating ultraviolet rays under the following conditions on the side of the release film bonded to the retardation film.

<Ultraviolet irradiation conditions>

‧Using the electrodeless lamp made by Xiuqiong Co., Ltd. H bulb

‧illuminance 600mW/cm ² , light quantity 150mJ/cm ²

UV illuminance. The light meter uses "UVPF-36" manufactured by Aegula Fegus.

Fig. 7 is a schematic cross-sectional view showing the layer constitution of the composite polarizing plate produced herein. In other words, the composite polarizing plate 13 produced in this example has the following layer configuration.

Examples 4 to 11

Transparent protective layer 2 / polarizer 1 / first pressure-sensitive adhesive layer 7a (light diffusion sexy pressure adhesive layer, 25 μm) / phase difference plate (λ / 4 plate) 5 / second pressure-sensitive adhesive layer 6 (feel Pressure-bonding layer, 25 μm) / release film 9.

Comparative Examples 4 to 5

Transparent protective layer 2 / polarizer 1 / first pressure-sensitive adhesive layer 7a (pressure-sensitive adhesive layer containing light diffusing agent, 25 μm) / phase difference plate (λ / 4 plate) 5 / second pressure-sensitive adhesive layer 6 (pressure-sensitive adhesive layer, 25 μm) / release film 9.

(d') Evaluation results of composite polarizers

The composite polarizing plates of Examples 4 to 11 which satisfy the requirements of the present invention are excellent in durability as compared with the composite polarizing plates of Comparative Examples 4 to 5 which satisfy the requirements of the present invention, as shown in Table 3-2.

[Table 2]

[table 3]

[Table 4]

[Industry use value]

The composite polarizing plate comprising the polarizer and the phase difference plate and the pressure-sensitive adhesive layer of the present invention can be used for laminating optical members laminated to other optical layers, and combining the polarizing plate or the laminated optical member with the liquid crystal An image display device in which an image display element of a unit cell or the like is combined.

1. . . Polarized photon

2,3. . . Transparent protective layer

4. . . Phase difference plate (may be λ/2 board)

5. . . Phase difference plate (may be λ/4 board)

6,7,8. . . Pressure-sensitive adhesive layer (may also form a light-diffusing pressure-sensitive adhesive layer)

7a, 8a. . . Light diffusion sexy pressure adhesive layer

9. . . Release film

11~15. . . Composite polarizer

18. . . Optical layer showing other optical functions

20. . . Laminated optical member

30. . . Liquid crystal cell

40. . . Polarizer (known)

41. . . Composite polarizer (known)

[Fig. 1] Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of a composite polarizing plate of the present invention.

[Fig. 2] Fig. 2 is a schematic cross-sectional view showing another example of the layer configuration of the composite polarizing plate of the present invention.

[Fig. 3] Fig. 3 is a cross-sectional schematic view showing an example in which the composite polarizing plate and the laminated optical member of the present invention are used in a liquid crystal display device.

[Fig. 4] is a schematic cross-sectional view showing a layer structure of the composite polarizing plate produced in Example 1 and Comparative Example 1.

[Fig. 5] is a schematic cross-sectional view showing a layer structure of the composite polarizing plate produced in Example 2 and Comparative Example 2.

[Fig. 6] is a schematic cross-sectional view showing a layer of a composite polarizing plate produced in Example 3 and Comparative Example 3.

[Fig. 7] is a schematic cross-sectional view showing a layer of a composite polarizing plate produced in Examples 4-11 and Comparative Examples 4-5.

[Fig. 8] (A) is a composite polarizing plate obtained in Example 2, and (B) is a composite polarizing plate obtained in Comparative Example 2, and each of the samples after the thermal shock test is subjected to a transparent protective layer of a polarizer. An enlarged photo of the side view.

[Fig. 9] Fig. 9 is a cross-sectional schematic view showing an example of a layer configuration of a conventional composite polarizing plate.

1. . . Polarized photon

2. . . Transparent protective layer

5. . . Phase difference plate (may be λ/4 board)

6, 7. . . Pressure-sensitive adhesive layer (may also form a light-diffusing pressure-sensitive adhesive layer)

9. . . Release film

11. . . Composite polarizer

Claims (20)

A composite polarizing plate in which a transparent protective layer is disposed on one surface of a polarizer formed of a polyvinyl alcohol-based resin film, and at least one phase is laminated on the other surface of the polarizer via a first pressure-sensitive adhesive layer a composite polarizing plate formed by disposing a second pressure-sensitive adhesive layer on the outer side of the phase difference plate located farthest from the polarizer, characterized by a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive a light-diffusing pressure-sensitive adhesive layer having at least one layer of a pressure-sensitive adhesive layer containing a light diffusing agent and having a storage modulus of 0.15 to 10 MPa at 23 ° C, and comprising a light-diffusing pressure-bonding layer The light-diffusing agent of the agent layer is a fine particle having a refractive index different from the adhesive resin constituting the pressure-sensitive adhesive layer, and the amount of the light diffusing agent is from 1 to 40% by mass based on the weight of the adhesive resin. The composite polarizing plate of claim 1, wherein the light-diffusing sexy pressure-sensitive adhesive layer has a storage modulus of 0.15 to 10 MPa at 80 °C. The composite polarizing plate of claim 1 or 2, wherein the phase difference plate is one, and the polarizer and the phase difference plate are bonded via the first pressure-sensitive adhesive layer. The composite polarizing plate of claim 1 or 2, wherein the phase difference plates are two sheets, and the two phase difference plates are bonded via the third pressure-sensitive adhesive layer. The composite polarizing plate of claim 1 or 2, wherein at least the first pressure-sensitive adhesive layer is formed by a light-diffusing pressure-sensitive adhesive layer Adult. The composite polarizing plate of claim 4, wherein at least one of the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer is formed by a light-diffusing pressure-sensitive adhesive layer. The composite polarizing plate according to claim 1 or 2, wherein the light-diffusing pressure-sensitive adhesive layer contains a light diffusing agent having an average particle diameter of 0.1 to 20 μm and has a storage elastic modulus of 0.3 to 10 MPa at 23 ° C. The haze value is 5% or more. The composite polarizing plate of claim 7, wherein the light-diffusing sexy pressure-sensitive adhesive layer has a storage modulus of 0.3 to 10 MPa at 80 °C. For example, in the composite polarizing plate of claim 8, wherein the light diffusion type pressure-sensitive adhesive layer has a gel fraction of 60% or more. The composite polarizing plate of claim 9, wherein the light-diffusing/small adhesive layer is dispersed in an adhesive resin formed of (A) an acrylic copolymer and (B) an active energy ray-curable compound; On the adhesive material of the diffusing agent, the person formed by the active energy ray is irradiated. The composite polarizing plate of claim 10, wherein the (B) active energy ray-curable compound is a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1,000. The composite polarizing plate of claim 11, wherein the polyfunctional (meth) acrylate monomer is a ring structure. The composite polarizing plate of claim 12, wherein the polyfunctional (meth) acrylate monomer has an isomeric cyanate structure By. The composite polarizing plate of claim 10, wherein the ratio of the (A) acrylic copolymer to the (B) active energy ray-curable compound is in a mass ratio of 100:1 to 100:100. The composite polarizing plate of claim 10, wherein the adhesive material is another one containing (C) a crosslinking agent. The composite polarizing plate of claim 10, wherein the adhesive material is additionally containing (D) a decane coupling agent. For example, in the composite polarizing plate of claim 1 or 2, the haze value of the light-diffusing sexy pressure-sensitive adhesive layer is 20 to 90%. The composite polarizing plate of claim 1 or 2, wherein the light-diffusing pressure-sensitive adhesive layer has a thickness of 1 to 40 μm. A laminated optical member characterized by being a laminate of a composite polarizing plate according to any one of claims 1 to 18 and an optical layer exhibiting other optical functions. An image display device comprising an image display element, a composite polarizing plate according to any one of claims 1 to 18, or a laminated optical member of claim 19 of the patent application.