Optical laminate, optical laminate with a bonding layer, and method for manufacturing the same

Abstract

The present application provides an optical laminate in which a reduction in optical properties can be expected to be suppressed in an optical laminate having a phase difference layer with a small Martens hardness, and an optical laminate with a bonding layer and a method for manufacturing the same. The optical laminate has, in order, a polarizing plate having a protective layer on one or both sides of a linearly polarizing layer, a first phase difference layer, and a second phase difference layer. The first phase difference layer includes a first liquid crystal layer as a cured product layer of a polymerizable liquid crystal compound, and the second phase difference layer includes a second liquid crystal layer as a cured product layer of a polymerizable liquid crystal compound. The Martens hardness (H1) at a press speed of 1 mN / 5 s and a creep time of 5 s of the second phase difference layer is 10 N / mm 2 The ratio (H2 / H1) of the Martens hardness (H2) at a press speed of 1 mN / 5 s and a creep time of 5 s on the second phase difference layer side of the optical laminate to the Martens hardness (H1) is 15 or more.

Description

Technical Field

[0001] This invention relates to optical laminates, optical laminates with bonding layers, and methods for manufacturing the same. Background Technology

[0002] Organic EL displays using organic light-emitting diodes (OLEDs) offer advantages over liquid crystal displays (LCDs) in terms of weight reduction and thinness. Furthermore, they provide high image quality, including a wide viewing angle, fast response time, and high contrast. Therefore, they are used in various fields such as smartphones, televisions, and digital cameras. In organic EL displays, to suppress the reduction in visibility caused by reflection of external light, it is known to improve anti-reflective performance by using circularly polarizing plates, which are obtained by stacking linear polarization layers and phase difference layers.

[0003] For example, Patent Document 1 discloses a scheme in which two liquid crystal layers with phase difference characteristics are formed by curing a liquid crystal material, and a laminate is formed by stacking the two liquid crystal layers. Patent Document 1 also discloses a scheme in which, in the case of winding the laminate, the outermost layer of the laminate may be damaged. In order to effectively avoid this damage, the pencil hardness of the liquid crystal layer or alignment film constituting the outermost layer of the laminate is increased.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-34851 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Depending on the type of retardation layer, which includes the liquid crystal layer formed by curing the liquid crystal material, it is sometimes impossible to increase the surface hardness, and a retardation layer with low surface hardness must be used to manufacture laminates such as circular polarizers. When using a retardation layer with low surface hardness to manufacture laminates, scratches have been found to form on the retardation layer during product processing such as transporting the laminate. These scratches can lead to a decrease in the optical properties of the laminate containing the retardation layer, such as light leakage in the scratched area due to the retardation layer not exhibiting a phase difference, and discoloration of reflected light in the scratched area due to changes in the phase difference of the retardation layer.

[0009] The present invention provides an optical laminate that can suppress the reduction of optical properties even in an optical laminate with a phase difference layer having low Martens hardness, and provides an optical laminate with an bonding layer and a method for manufacturing the same.

[0010] means for solving problems

[0011] The present invention provides the following optical laminate, optical laminate with bonding layer and method for manufacturing thereof.

[0012] [1] An optical laminate is an optical laminate having, sequentially, a polarizing plate having a protective layer on one or both sides of a linear polarizing layer, a first phase difference layer, and a second phase difference layer.

[0013] The first phase reversal layer comprises a first liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound.

[0014] The second phase reversal layer comprises a second liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound.

[0015] The Martens hardness H1 of the second phase difference layer at a pressurization rate of 1mN / 5s and a creep time of 5s is 10N / mm. 2 the following,

[0016] The ratio (H2 / H1) of the martensitic hardness H2 to the martensitic hardness H1 at a pressure rate of 1 mN / 5 s and a creep time of 5 s on the second phase difference layer side of the optical laminate is 15 or more.

[0017] [2] An optical laminate is an optical laminate having, sequentially, a polarizing plate having a protective layer on one or both sides of a linear polarizing layer, a first phase difference layer, and a second phase difference layer.

[0018] The first phase reversal layer comprises a first liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound.

[0019] The second phase reversal layer comprises a second liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound.

[0020] The Martens hardness H1 of the second phase difference layer at a pressurization rate of 1mN / 5s and a creep time of 5s is 10N / mm. 2 the following,

[0021] The number of scratches caused by the scratch test on the second phase difference layer side of the optical laminate is less than 10 per 20 mm.

[0022] [3] According to the optical laminate described in [1] or [2], wherein the first phase difference layer and the second phase difference layer are bonded together via a second bonding layer,

[0023] The second bonding layer is an adhesive curing layer.

[0024] [4] According to the optical laminate described in [3], wherein the adhesive curing layer constituting the second bonding layer is a curing layer of an active energy ray curable adhesive.

[0025] [5] An optical laminate according to any one of [1] to [4], wherein the polarizing plate and the first phase difference layer are bonded together via a first bonding layer.

[0026] The first bonding layer is an adhesive curing layer or an adhesive layer.

[0027] [6] According to the optical laminate described in [5], wherein the first bonding layer is an adhesive curing layer, which is a curing layer of an active energy ray curable adhesive.

[0028] [7] An optical laminate according to any one of [1] to [6], wherein the first phase difference layer is a laminate of the first liquid crystal layer and the first alignment layer.

[0029] [8] An optical laminate according to any one of [1] to [7], wherein the second phase difference layer is a laminate of the second liquid crystal layer and the second alignment layer.

[0030] The second alignment layer is disposed on the side of the second liquid crystal layer opposite to the side of the first phase difference layer.

[0031] [9] An optical laminate with an adhesive layer is an optical laminate having any one of the optical laminates described in [1] to [8] and a third adhesive layer.

[0032] The third bonding layer is located on the side of the second phase difference layer opposite to the side of the first phase difference layer.

[0033]

[10] An optical laminate with an adhesive layer as described in [9], wherein a release film capable of being peeled off relative to the third adhesive layer is provided on the side of the third adhesive layer opposite to the side of the second phase difference layer.

[0034]

[11] A method for manufacturing an optical laminate with an adhesive layer, which is the method for manufacturing an optical laminate with an adhesive layer described in [9] or

[10] , comprising:

[0035] The process of conveying the optical laminate while simultaneously bringing the conveyor roller against the second phase difference layer side of the optical laminate; and

[0036] The process of forming the third bonding layer on the side of the second phase difference layer of the optical laminate after the conveying process.

[0037]

[12] The method for manufacturing an optical laminate with an adhesive layer as described in

[11] further includes a step of laminating a release film on the side of the third adhesive layer opposite to the side of the second phase difference layer.

[0038] Invention Effects

[0039] According to the present invention, an optical laminate can be provided that is expected to suppress the degradation of optical properties. Furthermore, according to the present invention, an optical laminate with an bonding layer and a method for manufacturing the same can also be provided. Attached Figure Description

[0040] Figure 1 This is a schematic cross-sectional view illustrating an example of the optical laminate of the present invention.

[0041] Figure 2 This is a schematic cross-sectional view illustrating another example of the optical laminate of the present invention.

[0042] Figure 3 This is a schematic cross-sectional view illustrating an example of an optical laminate with an adhesive layer according to the present invention.

[0043] Figure 4 This is a schematic cross-sectional view illustrating another example of an optical laminate with an adhesive layer according to the present invention.

[0044] Figure 5 This is a schematic cross-sectional view illustrating an example of the manufacturing process of the optical laminate of the present invention.

[0045] Figure 6 This is a schematic cross-sectional view illustrating another example of the manufacturing process of the optical laminate of the present invention.

[0046] Figure 7 This is a schematic diagram illustrating an example of the manufacturing process of an optical laminate with an adhesive layer according to the present invention.

[0047] Figure 8 This is a schematic diagram illustrating another example of the manufacturing process of the optical laminate with an adhesive layer according to the present invention.

[0048] Explanation of reference numerals in the attached figures

[0049] 1. Optical laminates 1a and 1b; 3. Optical laminates 3a and 3b with bonding layers; 10 First retardation layer; 11 First alignment layer; 12 First liquid crystal layer; 15 First substrate layer; 18 First retardation layer with substrate layer; 20 Second retardation layer; 21 Second alignment layer; 22 Second liquid crystal layer; 25 Second substrate layer; 28 Second retardation layer with substrate layer; 31 First bonding layer; 32 Second bonding layer; 33 Third bonding layer; 35 Release film; 36 Bonding layer with release film; 40 Polarizing plate; 51 Conveyor roller; 53 Bonding roller. Detailed Implementation

[0050] Hereinafter, preferred embodiments of the optical laminate, the optical laminate with an adhesive layer, and the manufacturing method thereof of the present invention will be described with reference to the accompanying drawings.

[0051] (Optical laminate)

[0052] Figure 1 and Figure 2 This is a schematic cross-sectional view illustrating an example of the optical laminate of this embodiment. The optical laminates 1a and 1b of this embodiment (hereinafter sometimes referred to together as "optical laminate 1") are as follows... Figure 1 and Figure 2 As shown, the system sequentially comprises a polarizing plate 40 having protective layers on one or both sides of the linear polarizing layer, a first phase reversal layer 10, and a second phase reversal layer 20. The first phase reversal layer 10 comprises a first liquid crystal layer 12, which is a cured layer of a polymerizable liquid crystal compound. The second phase reversal layer 20 comprises a second liquid crystal layer 22, which is a cured layer of a polymerizable liquid crystal compound. The martensite hardness H1 (hereinafter sometimes referred to as "the martensite hardness H1 of the second phase reversal layer 20") of the second phase reversal layer 20 at a pressure rate of 1 mN / 5 s and a creep time of 5 s is 10 N / mm. 2 the following.

[0053] The optical laminate 1 satisfies at least one of [a] and [b] below.

[0054] [a] The ratio (H2 / H1) of the martensitic hardness H2 (hereinafter sometimes referred to as "the martensitic hardness H2 of the optical laminate 1") to the martensitic hardness H1 at a pressure rate of 1 mN / 5 s and a creep time of 5 s on the second phase difference layer 20 side of the optical laminate 1 is 15 or more.

[0055] [b] The number of scratches caused by the scratch test on the second phase difference layer 20 side of the optical laminate 1 is less than 10 scratches per 20 mm.

[0056] In the optical laminate 1, the first phase difference layer 10 may be the first liquid crystal layer 12 itself, which is a cured layer of a polymeric liquid crystal compound, or it may be a laminate of the first liquid crystal layer 12 and the first alignment layer 11. Figure 1 In the optical laminate 1a shown, the first alignment layer 11 is disposed on the polarizer 40 side of the first liquid crystal layer 12; however, it can also be like... Figure 2 As shown in the optical stack 1b, the first alignment layer 11 is disposed on the side of the second phase difference layer 20 of the first liquid crystal layer 12.

[0057] In the optical laminate 1, the second retardation layer 20 can be the second liquid crystal layer 22 itself, which is a cured layer of a polymeric liquid crystal compound, or it can be a laminate of the second liquid crystal layer 22 and the second alignment layer 21. The second alignment layer 21 is usually disposed on the side of the second liquid crystal layer 22 opposite to the side of the first retardation layer 10.

[0058] The martensitic hardness H1 of the second phase difference layer 20 is 10 N / mm. 2 The following can also be 9N / mm 2 The following can also be 8N / mm 2 The following can also be 7N / mm 2 The following can also be 6N / mm 2 Below that, it is typically 1 N / mm 2 The above describes the Martens hardness H1 of the second retardation layer 20. For example, it can be adjusted by the type of polymeric liquid crystal compound constituting the second liquid crystal layer 22, the type of polymerization initiator, the degree of curing (degree of polymerization) of the polymeric liquid crystal compound, and the thickness of the second liquid crystal layer 22. In the case of including the second alignment layer 21, it can be adjusted by the type of material constituting the second alignment layer 21, the degree of curing (degree of polymerization) of the second alignment layer 21, and the thickness of the second alignment layer 21. The Martens hardness H1 of the second retardation layer 20 can be measured using the method described in the embodiments described later. It can be measured in the state where the second retardation layer is laminated on a glass plate with an adhesive layer sandwiched between it, as described in the embodiments described later.

[0059] The martensitic hardness H2 of optical laminate 1 can be set to, for example, 10 N / mm. 2 The above can also be 30 N / mm. 2 The above can also be 50 N / mm. 2 The above can also be 80 N / mm. 2 The above can also be 100 N / mm. 2 The above can also be 120 N / mm. 2 The above can also be 140 N / mm. 2 The above is typically 300 N / mm. 2The martensitic hardness H2 of the optical laminate 1 can be adjusted, for example, by using the martensitic hardness H1 of the second retardation layer 20, the types of the first bonding layer 31 and the second bonding layer 32 (described later), the type of polymeric liquid crystal compound constituting the first liquid crystal layer 12, the type of polymerization initiator, the degree of curing (degree of polymerization) of the polymeric liquid crystal compound, and the thickness of the first liquid crystal layer 12. In the case where a first alignment layer 11 is included, the martensitic hardness H2 can be adjusted by using the type of material constituting the first alignment layer 11, the degree of curing (degree of polymerization) of the first alignment layer 11, and the thickness of the first alignment layer 11. The martensitic hardness H2 of the optical laminate 1 can be measured using the method described in the embodiments described later, and can be measured in the state where the optical laminate is laminated on a glass plate via an adhesive layer, as described in the embodiments described later.

[0060] The ratio (H2 / H1) of the martensitic hardness H2 of the optical laminate 1 to the martensitic hardness H1 of the second retardation layer 20 is 15 or more, or it can be 20 or more, or it can be 25 or more, or it can be 30 or more, or it can be 50 or more, or it can be 70 or more. By making the ratio (H2 / H1) within the above range, the martensitic hardness H2 of the optical laminate 1 is sufficiently large relative to the martensitic hardness H1 of the second retardation layer 20. Therefore, it is considered that even if the martensitic hardness H1 of the second retardation layer 20 on the surface side of the optical laminate 1 is small, and the surface of the optical laminate 1 (the surface on the side of the second retardation layer 20) is soft and easily deformable, the optical laminate 1 is still hard and not easily deformed. It is therefore speculated that even if the above-mentioned surface of the optical laminate 1 is formed of a material that is easily deformable and easily produces scratches, the optical laminate 1 is not easily deformed, and thus the generation of scratches can be suppressed. Therefore, for the optical laminate 1, it is expected to suppress the reduction of optical properties caused by the scratches generated in the second phase difference layer 20, such as suppressing light leakage caused by the phase difference layer not exhibiting a phase difference in the scratched area, and color change of reflected light caused by the phase difference layer changing in the scratched area.

[0061] The number of scratches caused by the scratch test on the second retardation layer 20 side of the optical laminate 1 is 10 scratches / 20mm or less, or it can be 8 scratches / 20mm or less, or it can be 5 scratches / 20mm or less, or it can be 3 scratches / 20mm or less. By keeping the number of scratches caused by the scratch test within the above range, it is expected that an optical laminate 1 can be obtained that suppresses the reduction of optical properties such as light leakage and color change of reflected light caused by scratches on the second retardation layer 20. The number of scratches caused by the scratch test can be adjusted, for example, by adjusting the ratio (H2 / H1) described in [a] above, or by selecting the types of the first bonding layer 31 and the second bonding layer 32 described later. The number of scratches caused by the scratch test can be measured using the method described in the embodiments described later. The unit "scratches / 20mm" for the number of scratches indicates the number of scratches generated in an area with a width of 20mm due to the scratch test.

[0062] The optical laminate 1 preferably has a first bonding layer 31 for bonding the polarizer 40 to the first phase difference layer 10 and a second bonding layer 32 for bonding the first phase difference layer 10 to the second phase difference layer 20. The first bonding layer 31 and the second bonding layer 32 are each independently an adhesive-cured layer or an adhesive layer. Preferably, at least the second bonding layer 32 is an adhesive-cured layer, and more preferably, both are adhesive-cured layers.

[0063] By making the second bonding layer 32 an adhesive curing layer, it is possible to form the second bonding layer 32 with greater hardness and less deformation compared to the case where the second bonding layer 32 is an adhesive layer. The second bonding layer 32 is a bonding layer used to bond the first retardation layer 10 and the second retardation layer 20, and it can be provided in direct contact with the second retardation layer 20. Therefore, even if the second retardation layer 20 has a low Martens hardness H1 and is easily deformable, the second bonding layer 32, which is provided adjacent to the second retardation layer 20, is hard and less prone to deformation, thus suppressing the generation of scratches on the surface of the optical laminate 1 (the surface on the side of the second retardation layer).

[0064] By making the second bonding layer 32 and the first bonding layer 31 adhesive curing layers, compared to the case where the second bonding layer 32 is an adhesive curing layer and the first bonding layer 31 is an adhesive layer, the Martens hardness H2 of the optical laminate 1 can be increased. Therefore, the generation of scratches on the surface of the optical laminate 1 (the surface on the side of the second retardation layer) can be further suppressed, and it is expected that an optical laminate 1 with further suppression of the aforementioned reduction in optical properties such as light leakage and discoloration of reflected light can be obtained.

[0065] The adhesive curing layers constituting the first bonding layer 31 and the second bonding layer 32 are preferably curing layers of active energy radiation-curable adhesives, and more preferably curing layers of ultraviolet-curable adhesives. The first bonding layer 31 and the second bonding layer 32 may be the same adhesive curing layer or different adhesive curing layers.

[0066] The optical laminate 1 may have a protective film that can be peeled off relative to the polarizer 40 on the side of the polarizer 40 opposite to the side of the first phase difference layer 10. The protective film and the polarizer 40 can be bonded together by utilizing the adhesive properties of the protective film. The optical laminate 1 may be a single sheet or a long strip that has been wound into a roll shape for storage, transportation, etc.

[0067] The optical stack 1 can be used as a circular polarizer. When the optical stack 1 is a circular polarizer, for example, the first phase reversal layer 10 can be set as a 1 / 2 wavelength phase reversal layer, and the second phase reversal layer 20 can be set as a 1 / 4 wavelength phase reversal layer. Alternatively, one of the first phase reversal layer 10 and the second phase reversal layer 20 can be set as a 1 / 4 wavelength phase reversal layer with inverse wavelength dispersion, and the other can be set as a positive C-plate.

[0068] (Optical laminate with bonding layer)

[0069] Figure 3 and Figure 4 This is a schematic cross-sectional view illustrating an example of an optical laminate with an adhesive layer according to this embodiment. The optical laminates 3a and 3b with adhesive layers of this embodiment (hereinafter sometimes referred to together as "optical laminate 3 with adhesive layer") include an optical laminate 1 and a third adhesive layer 33. Figure 3 The optical laminate 3a shown has a third bonding layer 33 provided in the optical laminate 1a. Figure 4 The optical laminate 3b shown has a third bonding layer 33 disposed on the optical laminate 1b. The third bonding layer 33 is as follows... Figure 3 and Figure 4 As shown, it is located on the side opposite to the side of the first phase difference layer 10 of the second phase difference layer 20 of the optical laminate 1.

[0070] The third bonding layer 33 can be used to bond the optical laminate 1 to the image display element. The third bonding layer 33 is an adhesive curing layer or an adhesive layer.

[0071] The optical laminate 3 with the bonding layer may also have a release film 35 on the side of the third bonding layer 33 opposite to the side of the second retardation layer 20, which can be peeled off relative to the third bonding layer 33. It is preferable to provide the release film 35 when the third bonding layer 33 is an adhesive layer.

[0072] The optical laminate 3 with the bonding layer can be a single sheet or a long strip of material that is wound into a roll shape during storage, transportation, etc.

[0073] Since the optical laminate 3 with the bonding layer is a laminate obtained using the optical laminate 1, it is believed that the reduction of optical properties such as light leakage and color change of reflected light is suppressed.

[0074] (Method for manufacturing optical laminates (1))

[0075] Figure 5 This is a schematic cross-sectional view illustrating an example of the manufacturing process of the optical laminate of this embodiment.

[0076] Figure 1 The manufacturing method of the optical laminate 1a shown can be as follows: Figure 5 As shown, it includes:

[0077] The process of preparing a first phase retardation layer 18 with a first phase retardation layer 10 on a first substrate layer 15 ( Figure 5 (a));

[0078] The process of preparing to form a second phase retardation layer 28 with a substrate layer on a second substrate layer 25, wherein a second phase retardation layer 20 is formed. Figure 5 (b));

[0079] The process of laminating the first phase difference layer 10 side of the first phase difference layer 18 with a substrate layer and the second phase difference layer 20 side of the second phase difference layer 28 with a substrate layer via the second bonding layer 32. Figure 5 (c));

[0080] The process of peeling off the first substrate layer 15 after the process of laminating the second bonding layer 32. Figure 5 (d)

[0081] The process of bonding the exposed surface after peeling off the first substrate layer 15 to the polarizing plate 40 via the first bonding layer 31 ( Figure 5 (e)); and

[0082] The process of peeling off the second substrate layer 25 after the process of bonding via the first bonding layer 31.

[0083] The first phase difference layer 18 with a substrate layer can be obtained by coating a liquid crystal layer forming composition containing a polymerizable liquid crystal compound onto the first substrate layer 15 via or without the first alignment layer 11 and drying it to polymerize and cure the polymerizable liquid crystal compound to form the first liquid crystal layer 12. Figure 5The diagram shows the first phase difference layer 18 as a stack of the first alignment layer 11 and the first liquid crystal layer 12; however, the first phase difference layer 18 may also not include the first alignment layer 11.

[0084] The second phase difference layer 28 with a substrate layer can be obtained by coating a liquid crystal layer forming composition containing a polymerizable liquid crystal compound onto the second substrate layer 25 via or without the second alignment layer 21 and drying it to polymerize and cure the polymerizable liquid crystal compound to form the second liquid crystal layer 22. Figure 5 The diagram shows the second phase difference layer 28 as a stack of the second alignment layer 21 and the second liquid crystal layer 22; however, the second phase difference layer 28 may also not include the second alignment layer 21.

[0085] In the process of laminating the second adhesive layer 32, for example, firstly, a second adhesive composition layer for forming the second adhesive layer 32 is formed on the side of the first phase difference layer 10 with the substrate layer 18 and / or the side of the second phase difference layer 20 with the substrate layer 28. Then, after laminating the first phase difference layer 18 with the substrate layer and the second phase difference layer 28 with the substrate layer via the second adhesive composition layer, the second adhesive layer 32 is formed from the second adhesive composition layer. The method for forming the second adhesive layer 32 from the second adhesive composition layer can be selected according to the type of the second adhesive composition layer. For example, if the adhesive contained in the second adhesive composition is an adhesive, the adhesive can be cured by irradiation with active energy rays, heat treatment, etc., thereby forming the second adhesive layer 32. If the adhesive contained in the second adhesive composition is an adhesive, the second adhesive composition layer can be set as the second adhesive layer 32. Thus, a laminate consisting of a first substrate layer 15, a first phase reversal layer 10 (first alignment layer 11, first liquid crystal layer 12), a second bonding layer 32, a second phase reversal layer 20 (second liquid crystal layer 22, second alignment layer 21), and a second substrate layer 25 can be obtained in sequence. Figure 5 (c)).

[0086] In the process of peeling off the first substrate layer 15, from Figure 5 The first substrate layer 15 is peeled off from the laminate shown in (c). In the process of peeling off the first substrate layer 15, only the first substrate layer 15 may be peeled off; however, if the first alignment layer 11 is present, the first alignment layer 11 may also be peeled off along with the first substrate layer 15. Thus, a laminate in which the first phase reversal layer 10 (first alignment layer 11, first liquid crystal layer 12), the second bonding layer 32, the second phase reversal layer 20 (second liquid crystal layer 22, second alignment layer 21), and the second substrate layer 25 are sequentially stacked can be obtained. Figure 5 (d)

[0087] In the process of bonding via the first bonding layer 31, for example, firstly, in Figure 5 The exposed side of the laminate shown in (d) after peeling off the first substrate layer 15 and / or the polarizing plate 40 forms a first adhesive composition layer for forming the first bonding layer 31. Then, the first adhesive composition layer is applied to the laminate. Figure 5 After the laminate shown in (d) is laminated with the polarizer 40, a first bonding layer 31 is formed from the first adhesive composition layer. The method for forming the first bonding layer 31 from the first adhesive composition layer can be selected according to the type of the first adhesive composition layer; for example, the method described in the method for forming the second bonding layer 32 from the second adhesive composition layer can be used. Thus, a laminate in which the polarizer 40, the first bonding layer 31, the first retardation layer 10 (first alignment layer 11, first liquid crystal layer 12), the second bonding layer 32, the second retardation layer 20 (second liquid crystal layer 22, second alignment layer 21), and the second substrate layer 25 are sequentially laminated can be obtained. Figure 5 (e)).

[0088] In the process of peeling off the second substrate layer 25, from Figure 5 The second substrate layer 25 is peeled off from the laminate shown in (e). In the process of peeling off the second substrate layer 25, only the second substrate layer 25 may be peeled off; however, if the second alignment layer 21 is present, the second alignment layer 21 may also be peeled off along with the second substrate layer 25. Thus, a result can be obtained... Figure 1 The optical laminate 1a shown.

[0089] Before forming the first adhesive composition layer and the second adhesive composition layer, one or both of the bonding surfaces of each layer bonded by the first adhesive layer 31 and the second adhesive layer 32 may be subjected to easy-bonding treatments such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment, and anchor coating treatment.

[0090] (Method for manufacturing optical laminates (2))

[0091] Figure 6 This is a schematic cross-sectional view illustrating another example of the manufacturing process of the optical laminate of this embodiment. Figure 2 The manufacturing method of the optical laminate 1b shown can be as follows: Figure 5 and Figure 6 As shown, it includes:

[0092] The process of preparing a first phase retardation layer 18 with a first phase retardation layer 10 on a first substrate layer 15 ( Figure 5 (a));

[0093] The process of preparing to form a second phase retardation layer 28 with a substrate layer on a second substrate layer 25, wherein a second phase retardation layer 20 is formed. Figure 5 (b));

[0094] The process of laminating the first phase retardation layer 10 side of the first phase retardation layer 18 with the substrate layer to the polarizing plate 40 via the first bonding layer 31. Figure 6 (a));

[0095] The process of peeling off the first substrate layer 15 after the process of laminating the first bonding layer 31. Figure 6 (b));

[0096] The process of bonding the surface exposed by peeling off the first substrate layer 15 to the second phase difference layer 20 side of the second phase difference layer 28 with the substrate layer via the second bonding layer 32. Figure 6 (c)); and

[0097] The process of peeling off the second substrate layer 25 after the process of bonding via the second bonding layer 32.

[0098] The above-described method can be cited as a method for obtaining the first phase difference layer 18 with a substrate layer and the second phase difference layer 28 with a substrate layer. Figure 6 The diagram shows a case where the first retardation layer 18 is a stack of the first alignment layer 11 and the first liquid crystal layer 12; however, the first retardation layer 18 may also not include the first alignment layer 11. Similarly, Figure 6 The diagram shows the second phase difference layer 28 as a stack of the second alignment layer 21 and the second liquid crystal layer 22; however, the second phase difference layer 28 may also not include the second alignment layer 21.

[0099] In the process of laminating via the first bonding layer 31, for example, firstly, a first adhesive composition layer for forming the first bonding layer 31 is formed on the side of the first phase reversal layer 10 with the substrate layer 18 and / or the polarizer 40. Then, after laminating the first phase reversal layer 18 with the substrate layer and the polarizer 40 via the first adhesive composition layer, the first bonding layer 31 is formed from the first adhesive composition layer. The method described above can be cited as a method for forming the first bonding layer 31 from the first adhesive composition layer. Thus, a laminate in which the polarizer 40, the first bonding layer 31, the first phase reversal layer 10 (first liquid crystal layer 12, first alignment layer 11), and the first substrate layer 15 are sequentially laminated can be obtained. Figure 6 (a)

[0100] In the process of peeling off the first substrate layer 15, from Figure 6The first substrate layer 15 is peeled off from the laminate shown in (a). In the process of peeling off the first substrate layer 15, only the first substrate layer 15 can be peeled off; however, if the first alignment layer 11 is present, the first alignment layer 11 can also be peeled off along with the first substrate layer 15. Thus, a laminate in which the polarizer 40, the first bonding layer 31, and the first phase difference layer 10 (first liquid crystal layer 12, first alignment layer 11) are sequentially stacked can be obtained. Figure 6 (b)

[0101] In the process of bonding via the second bonding layer 32, for example, firstly, in Figure 6 A second adhesive composition layer for forming the second bonding layer 32 is formed on the exposed surface side of the laminate shown in (b) where the first substrate layer 15 is peeled off and / or on the second phase difference layer 20 side where the second phase difference layer 28 with the substrate layer is attached. Then, the second adhesive composition layer is applied to the laminate. Figure 6 After the laminate shown in (b) is laminated with the second phase reversal layer 28 having a substrate layer, the second bonding layer 32 is formed by the second adhesive composition layer. The method described above can be used to form the second bonding layer 32 from the second adhesive composition layer. Thus, a laminate in which the polarizer 40, the first bonding layer 31, the first phase reversal layer 10 (first liquid crystal layer 12, first alignment layer 11), the second bonding layer 32, the second phase reversal layer 20 (second liquid crystal layer 22, second alignment layer 21), and the second substrate layer 25 are sequentially laminated, can be obtained. Figure 6 (c)).

[0102] In the process of peeling off the second substrate layer 25, from Figure 6 The second substrate layer 25 is peeled off from the laminate shown in (c). In the process of peeling off the second substrate layer 25, only the second substrate layer 25 may be peeled off; however, if the second alignment layer 21 is present, the second alignment layer 21 may also be peeled off along with the second substrate layer 25. Thus, a result can be obtained... Figure 2 The optical laminate 1b shown.

[0103] Before forming the first adhesive composition layer and the second adhesive composition layer, one or both of the bonding surfaces of each layer bonded by the first adhesive layer 31 and the second adhesive layer 32 may be subjected to easy-bonding treatments such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment, and anchor coating treatment.

[0104] (Manufacturing method of optical laminate with bonding layer)

[0105] Figure 7 and Figure 8 This is a schematic diagram illustrating an example of the manufacturing process of an optical laminate with an adhesive layer according to this embodiment. In the diagram, the arrows indicate the transport direction. Figure 7and Figure 8 The present invention illustrates a method for manufacturing an optical laminate 3 with an adhesive layer on a long strip using a roll-to-roll method, but is not limited to this method. The manufacturing method of the optical laminate 3 with an adhesive layer is as follows: Figure 7 and Figure 8 As shown, it includes:

[0106] When the conveyor roller 51 is brought into contact with the optical laminate 1, Figure 1 and Figure 2 The process of simultaneously conveying optical laminate 1 to the second phase difference layer 20 side; and

[0107] After the transport process, a third bonding layer 33 is formed on the side of the second phase difference layer 20 of the optical laminate 1.

[0108] The manufacturing method of the optical laminate with the bonding layer may further include a step of laminating a release film 35 on the side of the third bonding layer 33 opposite to the side of the second phase difference layer 20.

[0109] In the process of conveying the optical laminate 1, the long strip of optical laminate 1 is rolled out, and the optical laminate 1 is conveyed simultaneously with the conveyor roller 51 abutting against the side of the second phase difference layer 20 of the optical laminate 1. There may be one or more conveyor rollers 51 abutting against the side of the second phase difference layer of the optical laminate 1. Alternatively, there may be one or more conveyor rollers abutting against the side of the polarizer 40 of the optical laminate 1. The conveyor roller 51 may be a drive roller with a drive source or a guide roller without a drive source.

[0110] In the process of forming the third bonding layer 33, the third bonding layer 33 is formed on the side of the optical laminate 1 that abuts against the transport roller 51, the side of the second phase difference layer 20. Examples of methods for forming the third bonding layer 33 include... Figure 7 The method shown is to form a third adhesive composition layer by applying a third adhesive composition for forming a third adhesive layer 33 using a coating apparatus 52; such as Figure 8 The method shown is as follows: a third bonding layer 33 is formed on the release film 35 on the side of the second phase difference layer 20 of the optical laminate 1, and the bonding layer 36 with the release film is stacked on the side of the third bonding layer 33.

[0111] like Figure 7 As shown, when coating the optical laminate 1 with the third adhesive composition, known coating methods such as extrusion, gravure coating, die coating, wire rod coating, squeegee coating, coater coating, and flexographic printing can be used.

[0112] like Figure 8As shown, when the optical laminate 1 is laminated with the bonding layer 36 having a release film, it can be pressed from above and below using bonding rollers 53 and the like positioned at the lamination location.

[0113] As described above, the surface of the optical laminate 1 on the side of the second phase difference layer 20 can suppress scratches caused by abrasions, etc. Therefore, even when the optical laminate 1 is transported while the transport roller 51 is abutting against the side of the second phase difference layer 20, scratches on the surface of the optical laminate 1 on the side of the second phase difference layer 20 can be suppressed. It is therefore believed that the optical laminate 3 with the third bonding layer 33 formed on the side of the second phase difference layer 20 that abuts against the transport roller 51 suppresses the reduction of optical properties such as light leakage and color change of reflected light caused by the aforementioned scratches.

[0114] In the optical laminate 1, a polarizing plate 40 is provided on one surface side of the first phase retardation layer 10, and a second phase retardation layer 20 is provided on the other surface side of the first phase retardation layer 10. The surface of the first phase retardation layer 10 is not exposed. Therefore, when manufacturing an optical laminate 3 with an bonding layer using the optical laminate 1, the first phase retardation layer 10 will not directly contact the conveyor roller, bonding roller, etc. As a result, in the manufacturing method of the optical laminate 3 with the bonding layer, scratches are less likely to occur on the first phase retardation layer 10.

[0115] The details of the optical laminate, the optical laminate with an adhesive layer, and the components used in their manufacturing methods will be described below.

[0116] (Linear polarization layer)

[0117] A linear polarizing layer has the property that, when unpolarized light is incident, it allows linearly polarized light with a vibration plane orthogonal to the absorption axis to pass through. The linear polarizing layer can comprise a polyvinyl alcohol (PVA)-based resin film, or it can be a cured film obtained by orienting dichroic pigments in a polymeric liquid crystal compound and polymerizing the liquid crystal compound.

[0118] Examples of linear polarizing layers comprising PVA-based resin films include linear polarizing layers obtained by dyeing hydrophilic polymer films such as polyvinyl alcohol (hereinafter sometimes simply referred to as "PVA") films, partially formalized PVA films, and partially saponified ethylene / vinyl acetate copolymer films using dichroic substances such as iodine and dichroic dyes, followed by stretching. Due to their excellent optical properties, linear polarizing layers obtained by dyeing PVA-based resin films with iodine and then uniaxially stretching them are preferred.

[0119] Polyvinyl alcohol (PVA) resins can be manufactured by saponifying polyvinyl acetate (PVC) resins. PVC resins can be polyvinyl acetate homopolymers, or copolymers of vinyl acetate with other monomers capable of copolymerizing with vinyl acetate. Examples of other monomers capable of copolymerizing with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides with ammonium groups.

[0120] The degree of saponification of polyvinyl alcohol (PVA) resins is typically around 85–100 mol%, preferably 98 mol% or higher. PVA resins can also be modified; for example, aldehyde-modified PVA formal or PVA acetal can be used. The average degree of polymerization of PVA resins is typically around 1000–10000, preferably around 1500–5000. The average degree of polymerization of PVA resins can be determined according to JIS K 6726 (1994). If the average degree of polymerization is less than 1000, it is difficult to obtain preferred polarization properties; if it is greater than 10000, poor film processability occurs.

[0121] The film obtained by forming this polyvinyl alcohol-based resin film can be used as a raw material film for a linear polarizing layer. There are no particular limitations on the method for forming the polyvinyl alcohol-based resin film; known methods can be used. The film thickness of the polyvinyl alcohol-based resin raw material film is, for example, about 10 to 100 μm, preferably about 10 to 60 μm, and more preferably about 15 to 30 μm.

[0122] Other methods for manufacturing linear polarizing layers containing PVA-based resin films include a method comprising the following steps: first, preparing a substrate film; coating the substrate film with a solution of a resin such as a polyvinyl alcohol-based resin; and then drying to remove the solvent, thereby forming a resin layer on the substrate film. It should be noted that a primer layer can be pre-formed on the surface of the substrate film where the resin layer is formed. As the substrate film, a resin film such as PET can be used. As the material for the primer layer, a resin obtained by crosslinking a hydrophilic resin used in the linear polarizing layer can be cited.

[0123] Then, the amount of solvent, such as moisture, in the resin layer is adjusted as needed. Next, the substrate film and the resin layer are uniaxially stretched. Then, the resin layer is stained with a dichroic pigment, such as iodine, causing the pigment to adsorb onto the resin layer and become oriented. Next, the resin layer with the adsorbed and oriented dichroic pigment is treated with a boric acid aqueous solution as needed, followed by a washing process to remove the boric acid solution. Thus, a film containing a linearly polarized layer, i.e., a resin layer with adsorbed and oriented dichroic pigment, can be manufactured. Each step can be performed using known methods.

[0124] The uniaxial stretching of the substrate film and resin layer can be performed before dyeing, during dyeing, or after boric acid treatment following dyeing, or separately at multiple stages. The substrate film and resin layer can be uniaxially stretched along the MD direction (film transport direction). In this case, stretching can be performed uniaxially between rollers with different circumferential speeds, or using hot rollers. Alternatively, the substrate film and resin layer can be uniaxially stretched along the TD direction (perpendicular to the film transport direction). In this case, a so-called tenter frame method can be used. Furthermore, the stretching of the substrate film and resin layer can be dry stretching performed in the atmosphere, or wet stretching performed while the resin layer is swollen using a solvent. To achieve the performance of the linear polarizing layer, the stretching ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. There is no particular upper limit to the stretching ratio; however, from the viewpoint of suppressing breakage, it is preferably 8 times or less.

[0125] The linearly polarized layer fabricated using the above method can be obtained by peeling off the substrate film after laminating the protective layer described above. According to this method, further thinning of the linearly polarized layer can be achieved.

[0126] As a method for manufacturing a cured film, i.e., a linear polarizing layer, obtained by orienting dichroic pigments in a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound, an example is a method in which a polarizing layer forming composition comprising a polymerizable liquid crystal compound and a dichroic pigment is coated onto a substrate film, and the polymerizable liquid crystal compound is polymerized and cured while maintaining a liquid crystal state to form a linear polarizing layer. The linear polarizing layer obtained in this manner is laminated onto the substrate film, and the linear polarizing layer with the substrate film can be used as a polarizing plate as described later.

[0127] As dichroic pigments, pigments with the property that the absorbance along the long axis of the molecule differs from that along the short axis can be used. For example, pigments having a maximum absorption wavelength (λmax) in the range of 300 to 700 nm are preferred. Examples of such dichroic pigments include acridine pigments, oxazine pigments, anthocyanins, naphthalene pigments, azo pigments, and anthraquinone pigments, with azo pigments being preferred. Examples of azo pigments include monoazo pigments, diazo pigments, triazo pigments, tetraazo pigments, and stilbene azo pigments, with diazo pigments and triazo pigments being more preferred.

[0128] The composition for forming a polarizing layer may include a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, and a polymerization inhibitor. Known substances may be used for the polymerizable liquid crystal compound, dichroic pigment, solvent, polymerization initiator, photosensitizer, and polymerization inhibitor contained in the polarizing layer forming composition; for example, substances exemplified in Japanese Patent Application Publication Nos. 2017-102479 and 2017-83843 may be used. Furthermore, the polymerizable liquid crystal compound may also be a compound exemplified as a polymerizable liquid crystal compound used to obtain the liquid crystal layers (first liquid crystal layer and second liquid crystal layer) described later. The method exemplified in the above-mentioned publications may also be used for the method of forming a linear polarizing layer using the polarizing layer forming composition.

[0129] The thickness of the linear polarizing layer is preferably 2 μm or more, more preferably 3 μm or more. Furthermore, the thickness of the linear polarizing layer is 25 μm or less, preferably 15 μm or less, more preferably 13 μm or less, and even more preferably 7 μm or less. It should be noted that the above-mentioned upper and lower limits can be combined arbitrarily.

[0130] (Polarizing plate)

[0131] A linear polarizing layer can be laminated with a protective layer on one or both sides via a known adhesive layer or bonding layer to form a polarizing plate. This polarizing plate is called a linear polarizing plate. As a protective layer that can be laminated on one or both sides of the linear polarizing layer, for example, a film formed from a thermoplastic resin with excellent transparency, mechanical strength, thermal stability, water resistance, isotropy, and tensile strength can be used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins having cyclic systems and norbornene structures (also called norbornene-based resins); (meth)acrylic resins; polyaryl ester resins; polystyrene resins; polyvinyl alcohol resins; and mixtures thereof. When protective layers are stacked on both sides of the linear polarizing layer, the resin compositions of the two protective layers can be the same or different. It should be noted that the term "(meth)acrylic acid" in this specification refers to any of the acrylic or methacrylic acid derivatives. The "(methyl)" in (meth)acrylates, etc., has the same meaning.

[0132] For films formed from thermoplastic resins, in order to improve the adhesion to linear polarization layers containing PVA-based resins and dichroic substances, surface treatments (such as corona treatment) can be performed, or thin layers such as primer layers (also known as base coats) can be formed.

[0133] The optimal moisture permeability of the protective layer under conditions of 40℃ temperature and 90% RH is 1–1500 g / m². 2 • 24hr. The moisture permeability of the protective layer under conditions of 40°C and 90% RH is preferably 1000 g / m². 2 • Less than 24 hours, preferably 100g / m 2 • Less than 24 hours, preferably 10g / m 2 • Less than 24 hours

[0134] Moisture permeability can be measured according to JIS Z 0208:1976.

[0135] It should be noted that, in the case of protective layers stacked on both sides of the linear polarization layer, the moisture permeability of the outer protective layer stacked on the visible side when the optical laminate is bonded to the optical display element is preferably the same as that of the inner protective layer stacked on the first bonding layer side, or the moisture permeability of the outer protective layer is smaller than that of the inner protective layer.

[0136] The protective layer can be, for example, a layer obtained by stretching the aforementioned thermoplastic resin, or it can be an unstretched layer (hereinafter sometimes referred to as "unstretched resin"). Examples of stretching processes include uniaxial stretching and biaxial stretching.

[0137] The stretching direction in the stretching process can be the length direction of the unstretched resin, a direction orthogonal to the length direction, or a direction obliquely intersecting the length direction. In the case of uniaxial stretching, the unstretched resin can be stretched in any of these directions. Biaxial stretching can be simultaneous biaxial stretching along two of these stretching directions, or it can be sequential biaxial stretching where stretching is performed in one direction followed by stretching in another direction.

[0138] Stretching can be performed, for example, by using two or more pairs of clamping rollers with increased downstream circumferential speed to stretch along the length direction, or by holding both ends of the unstretched resin with chucks and stretching it in a direction orthogonal to the length direction. In this case, the desired phase difference and wavelength dispersion can be controlled by adjusting the thickness of the stretched thermoplastic resin or by adjusting the stretching ratio.

[0139] The thickness of the protective layer is preferably 3 μm or more, more preferably 5 μm or more. Furthermore, the thickness of the protective layer is preferably 50 μm or less, more preferably 30 μm or less. It should be noted that the above-mentioned upper and lower limits can be combined arbitrarily.

[0140] (Protective film)

[0141] The protective film is a film used to coat and protect the surface of a polarizing plate, and it can be peeled off from the polarizing plate. The protective film can be a film with an adhesive layer formed on a resin film, or it can be formed from a self-adhesive film. The thickness of the protective film can be, for example, 30–200 μm, preferably 30–150 μm, and more preferably 30–120 μm.

[0142] Examples of resins constituting the protective film include polyolefin resins such as polyethylene resins and polypropylene resins; cyclic polyolefin resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; and (meth)acrylic resins. Polyester resins such as polyethylene terephthalate are preferred. The protective film can be a single-layer structure or a multilayer structure with two or more layers.

[0143] As the adhesive composition constituting the adhesive layer of the protective film, the same adhesive composition as that constituting the adhesive layer described later can be used. Alternatively, the protective film can be obtained by coating the adhesive composition onto the surface of the resin film for the protective film and then drying it to form the adhesive layer. If necessary, to improve adhesion, surface treatment (e.g., corona treatment) can be performed on the coated surface of the adhesive composition for the resin film, or a thin layer such as a primer layer (also called a base coat) can be formed. Additionally, if necessary, a release layer can be provided to cover and protect the surface of the adhesive layer for the protective film opposite to the side of the resin film for the protective film. This release layer can be peeled off at an appropriate time when bonding with the polarizing plate.

[0144] A self-adhesive film is a film that can adhere itself without the need for an adhesive layer or other adhesion mechanism, and can maintain this adhesion. Self-adhesive films can be formed, for example, using polypropylene resins and polyethylene resins.

[0145] (First phase difference layer and second phase difference layer)

[0146] The first retardation layer can be a first liquid crystal layer that is a cured layer of a polymeric liquid crystal compound, or it can be a stack of a first liquid crystal layer and a first alignment layer. Similarly, the second retardation layer can be a second liquid crystal layer that is a cured layer of a polymeric liquid crystal compound, or it can be a stack of a second liquid crystal layer and a second alignment layer. The second retardation layer has the aforementioned martensitic hardness H1. The martensitic hardness of the first retardation layer is not particularly limited; it can be the same as or different from the aforementioned martensitic hardness H1.

[0147] The first and second phase difference layers (hereinafter sometimes referred to together as "phase difference layers") together possess phase difference characteristics, which can be adjusted primarily by utilizing the orientation state of the polymeric liquid crystal compound. Examples of phase difference layers include positive A layers, which impart a phase difference of λ / 4, and positive C layers, which exhibit vertical orientation.

[0148] The amount of polymerizable groups N shown in formula (A) of the phase retardation layer is preferably 0.67 or less, more preferably 0.64 or less. The amount of polymerizable groups N is generally 0.01 or more, preferably 0.03 or more.

[0149] [Mathematical Expression 1]

[0150]

[0151] [In the formula,

[0152] AL represents the number of structural units derived from the polymeric compounds constituting the resin, which forms an alignment layer, and the alignment layer forms a retardation layer. It should be noted that when the retardation layer is composed solely of a liquid crystal layer, AL = 0.

[0153] For Cwi, the content (mass %) of structural units from polymeric compounds i is expressed as the total number of structural units from the polymeric compounds in the resin constituting the orientation layer.

[0154] Mi represents the molecular weight of the polymeric compound i that constitutes the orientation layer.

[0155] Ni represents the number of polymeric groups in the polymeric compound i that constitutes the orientation layer.

[0156] For LC, when the liquid crystal layer is a cured layer of a polymeric liquid crystal compound, it represents the number of types of structural units derived from the polymeric liquid crystal compound constituting the liquid crystal layer.

[0157] For Cwj, the content (mass%) of structural units from polymeric liquid crystal compound j is represented by all structural units from the polymeric liquid crystal compound in the liquid crystal layer.

[0158] Mj represents the molecular weight of the polymeric liquid crystal compound j that constitutes the liquid crystal layer.

[0159] Nj represents the number of polymeric groups possessed by polymeric liquid crystal compound i that constitutes the liquid crystal layer.

[0160] L AL The thickness of the alignment layer is indicated in μm.

[0161] L LcThe thickness of the liquid crystal layer is indicated in μm.

[0162] L total L represents AL With L Lc The sum of.

[0163] (First liquid crystal layer and second liquid crystal layer)

[0164] The first and second liquid crystal layers (hereinafter sometimes referred to together as "liquid crystal layers") are cured layers formed by polymerizing a polymeric liquid crystal compound. In this specification, horizontal orientation is defined as the case where the optical axis of the polymeric liquid crystal compound is oriented horizontally relative to the plane of the substrate layer, and vertical orientation is defined as the case where the optical axis of the polymeric liquid crystal compound is oriented perpendicularly relative to the plane of the substrate layer. The optical axis refers to the direction in which a cross-section orthogonal to the optical axis is circular within a refractive index ellipsoid formed by the orientation of the polymeric liquid crystal compound; that is, the direction in which the refractive indices are equal in both directions. The first and second liquid crystal layers can be cured layers formed by polymerizing the same polymeric liquid crystal compound, or cured layers formed by polymerizing different polymeric liquid crystal compounds.

[0165] Examples of polymerizable liquid crystal compounds include rod-shaped and disc-shaped polymerizable liquid crystal compounds. One type or a mixture thereof can be used. When the rod-shaped polymerizable liquid crystal compound is horizontally or vertically oriented relative to the substrate layer, its optical axis is aligned with its long axis. When the disc-shaped polymerizable liquid crystal compound is oriented, its optical axis is located in a direction orthogonal to the disc surface. For example, the polymerizable liquid crystal compound described in Japanese Patent Application Publication No. 11-513019 (claim 1, etc.) can be suitably used as a rod-shaped polymerizable liquid crystal compound. As a disc-shaped polymerizable liquid crystal compound, the polymerizable liquid crystal compound described in Japanese Patent Application Publication No. 2007-108732 (paragraphs

[0020] to

[0067] , etc.) and Japanese Patent Application Publication No. 2010-244038 (paragraphs

[0013] to

[0108] , etc.) may be used appropriately.

[0166] To achieve in-plane phase difference in a liquid crystal layer formed by polymerizing a polymeric liquid crystal compound, the polymeric liquid crystal compound simply needs to be oriented in a suitable direction. When the polymeric liquid crystal compound is rod-shaped, in-plane phase difference is achieved by aligning its optical axis horizontally relative to the substrate layer plane; in this case, the optical axis direction is aligned with the slow axis direction. When the polymeric liquid crystal compound is disk-shaped, in-plane phase difference is achieved by aligning its optical axis horizontally relative to the substrate layer plane; in this case, the optical axis is orthogonal to the slow axis. The orientation state of the polymeric liquid crystal compound can be adjusted using a combination of an alignment layer and the polymeric liquid crystal compound.

[0167] A polymerizable liquid crystal compound is a compound having at least one polymerizable group and exhibiting liquid crystal properties. When two or more polymerizable liquid crystal compounds are used together, it is preferable that at least one of them has two or more polymerizable groups within its molecule. A polymerizable group refers to a group that participates in the polymerization reaction, and is preferably a photopolymerizable group. Here, a photopolymerizable group refers to a group that can participate in the polymerization reaction using active free radicals, acids, etc., generated by a photopolymerization initiator described later. Examples of polymerizable groups include vinyl, ethoxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, epoxyethyl, oxetane, styryl, allyl, etc. Acryloyloxy, methacryloyloxy, ethoxy, epoxyethyl, and oxetane are preferred, and acryloyloxy is more preferred. The liquid crystal properties of the polymerizable liquid crystal compound can be thermotropic or lyotropic. If thermotropic liquid crystals are classified according to their degree of order, they can be nematic liquid crystals or smectic liquid crystals.

[0168] The liquid crystal layer can be a single-layer structure or a multilayer structure with two or more layers. In the case of a multilayer structure with two or more layers, the liquid crystal layer with two or more layers can be formed on the substrate layer when preparing the first retardation layer and the second retardation layer with the substrate layer (described later). The thickness of the liquid crystal layer is preferably 0.5 μm or more, but can also be 1 μm or more, typically 10 μm or less, or 5 μm or less. The above upper and lower limits can be combined arbitrarily. If the thickness of the liquid crystal layer is 0.5 μm or more, sufficient durability is easily obtained. By making the thickness of the liquid crystal layer 10 μm or less, it is possible to achieve a thinner optical laminate.

[0169] (First orientation layer and second orientation layer)

[0170] The first and second alignment layers (hereinafter sometimes referred to together as "alignment layers") have alignment limiting forces that orient the liquid crystal compounds contained in the first and second liquid crystal layers formed on these alignment layers in a desired direction. The alignment layers can be vertical alignment layers where the molecular axes of the polymerizable liquid crystal compounds are oriented perpendicularly to the substrate layer, horizontal alignment layers where the molecular axes of the polymerizable liquid crystal compounds are oriented horizontally to the substrate layer, or tilted alignment layers where the molecular axes of the polymerizable liquid crystal compounds are tilted relative to the substrate layer. The first and second alignment layers can be the same alignment layer or different alignment layers.

[0171] As an alignment layer, an alignment layer is preferred that has solvent resistance, preventing dissolution by coating of the liquid crystal layer forming composition (described later), and heat resistance for heat treatment used for solvent removal and alignment of the polymerizable liquid crystal compound. Examples of alignment layers include an alignment polymer layer formed from an alignment polymer, a photoalignment polymer layer formed from a photoalignment polymer, and a groove alignment layer having a raised or recessed pattern and multiple grooves on its surface.

[0172] An orientation polymer layer can be formed by dissolving an orientation polymer in a solvent, coating the resulting composition onto a substrate layer (a first substrate layer or a second substrate layer), removing the solvent, and then performing a friction treatment as needed. In this case, the orientation restraint force can be arbitrarily adjusted in the orientation polymer layer formed by the orientation polymer using the surface state of the orientation polymer and the friction conditions.

[0173] A photo-oriented polymer layer can be formed by coating a composition containing a polymer or monomer with photoreactive groups and a solvent onto a substrate layer (a first substrate layer or a second substrate layer) and irradiating it with light such as ultraviolet light. Particularly when orientation-confining forces are present along the horizontal direction, it can be formed by irradiating with polarized light. In this case, the orientation-confining force in the photo-oriented polymer layer can be arbitrarily adjusted using polarized light irradiation conditions, etc.

[0174] The grooved alignment layer can be formed by methods such as: exposing and developing an exposure mask with patterned slits sandwiched between the surface of a photosensitive polyimide film to form a raised pattern; forming an uncured layer of active energy radiation-curable resin on a plate-shaped master disk with grooves on its surface, transferring the layer to a substrate layer (a first substrate layer or a second substrate layer) and curing it; forming an uncured layer of active energy radiation-curable resin on a substrate layer (a first substrate layer or a second substrate layer), pressing a roller-shaped master disk with raised and recessed surfaces onto the layer, thereby forming the raised and recessed surfaces and curing it.

[0175] Resins used to form alignment layers can be exemplified by resins obtained by polymerizing polymeric compounds. Polymeric compounds are compounds having polymeric groups and are generally non-liquid-liquid-liquid-state polymeric non-liquid-liquid-liquid-state compounds that do not form liquid crystals. The polymeric groups of the polymeric compound react with each other to polymerize the compound, thereby forming a resin. As for such resins, there are no particular limitations as long as they are resins that can be used as alignment layers for aligning polymeric liquid crystal compounds during the liquid crystal layer formation stage, are not contained in the phase retardation layer, and are known materials used as alignment layers. Cured products obtained by curing known monofunctional or polyfunctional (meth)acrylate monomers under a polymerization initiator can also be used.

[0176] Specifically, examples of (meth)acrylate monomers include 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono-2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol monophenyl ether acrylate, trimethylolpropane triacrylate, lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, methacrylic acid, and carbamate acrylates. It should be noted that the resin can be one of these or a mixture of two or more. This alignment layer can be peeled off together with the substrate layer after the liquid crystal layer is formed, before or after the lamination process with the polarizer, other phase reversal layers, etc.

[0177] To improve peelability relative to the substrate layer and impart film strength to the retardation layer, an alignment layer can be included in the retardation layer. When the retardation layer includes an alignment layer, the resin used as the alignment layer is preferably a cured product obtained by curing monofunctional or difunctional (meth)acrylate monomers, imide monomers, or vinyl ether monomers.

[0178] Examples of monofunctional (meth)acrylate monomers include alkyl (meth)acrylates with 4 to 16 carbon atoms, β-carboxyalkyl (meth)acrylates with 2 to 14 carbon atoms, alkylated phenyl (meth)acrylates with 2 to 14 carbon atoms, methoxy polyethylene glycol (meth)acrylates, phenoxy polyethylene glycol (meth)acrylates, and isobornyl (meth)acrylate.

[0179] Examples of difunctional (meth)acrylate monomers include 1,3-butanediol di(meth)acrylate; 1,3-butanediol (meth)acrylate; 1,6-hexanediol di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; neopentyl glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol diacrylate; bis(acryloyloxyethyl) ether of bisphenol A; ethoxylated bisphenol A di(meth)acrylate; propoxylated neopentyl glycol di(meth)acrylate; ethoxylated neopentyl glycol di(meth)acrylate; and 3-methylpentyl glycol di(meth)acrylate.

[0180] Examples of imide-based resins obtained by curing imide monomers include polyamides and polyimides. It should be noted that an imide-based resin can be one type of these resins or a mixture of two or more of them.

[0181] The resin used to form the orientation layer may contain monomers other than monofunctional and difunctional (meth)acrylate monomers, imide monomers and vinyl ether monomers. The proportion of monofunctional and difunctional (meth)acrylate monomers, imide monomers and vinyl ether monomers in the total monomers may be 50% by weight or more, preferably 55% by weight or more, and more preferably 60% by weight or more.

[0182] The first alignment layer and the second alignment layer can be of the same type or different types. When the alignment layer is included in the retardation layer, the thickness of the alignment layer is typically in the range of 10 nm to 10,000 nm. When the liquid crystal layer is horizontally aligned relative to the substrate layer, the thickness of the alignment layer is preferably 10 nm to 1,000 nm; when the liquid crystal layer is vertically aligned relative to the substrate layer, the thickness of the alignment layer is preferably 100 nm to 10,000 nm. By setting the thickness of the alignment layer within the above range, the peelability relative to the substrate layer can be improved, and film strength can be imparted to the retardation layer.

[0183] (Phase difference layer with substrate layer)

[0184] The first retardation layer and the second retardation layer with a substrate layer (hereinafter sometimes referred to together as "retardation layer with a substrate layer") can be obtained by coating a liquid crystal layer forming composition containing a polymerizable liquid crystal compound onto the substrate layer and drying it to polymerize the polymerizable liquid crystal compound, thereby forming a retardation layer containing a liquid crystal layer as a cured layer. If an alignment layer (described later) is formed on the substrate layer, it is sufficient to coat the liquid crystal layer forming composition onto the alignment layer. If the liquid crystal layer is a multilayer structure with two or more layers, the multilayer structure can be formed by sequentially coating the liquid crystal layer forming composition, etc.

[0185] Compositions for forming liquid crystal layers typically include a solvent in addition to a polymerizable liquid crystal compound. Preferably, organic solvents are used, such as amides (e.g., N,N-dimethylformamide), sulfoxides (e.g., dimethyl sulfoxide), heterocyclic compounds (e.g., pyridine), hydrocarbons (e.g., benzene, hexane), haloalkanes (e.g., chloroform, dichloromethane), esters (e.g., methyl acetate, ethyl acetate, butyl acetate), ketones (e.g., acetone, methyl ethyl ketone), and ethers (e.g., tetrahydrofuran, 1,2-dimethoxyethane). Haloalkanes and ketones are particularly preferred. Furthermore, two or more organic solvents may be used in combination.

[0186] The composition for forming a liquid crystal layer may further include additives such as polymerization initiators, reactive additives, and polymerization inhibitors. For these additives, the additives exemplified in Japanese Patent Application Publication No. 2015-163937, Japanese Patent Application Publication No. 2016-42185, International Publication No. 2016 / 158940, and Japanese Patent Application Publication No. 2016-224128 may be used.

[0187] The composition for forming a liquid crystal layer may include polymerizable monomers and surfactants, considering the uniformity and strength of the coated film. Examples of polymerizable monomers include free radical polymerizable or cationic polymerizable compounds. Multifunctional free radical polymerizable monomers are preferred. It should be noted that monomers capable of copolymerizing with the aforementioned polymerizable liquid crystal compound are preferred. The amount of polymerizable monomer used relative to the total mass of the polymerizable liquid crystal compound is preferably 1 to 50% by mass, more preferably 2 to 30% by mass. Examples of surfactants include known compounds; however, fluorinated compounds are preferred.

[0188] The composition for forming a liquid crystal layer may include various alignment agents such as vertical alignment agents on the polarizer interface side and vertical alignment agents on the air interface side, and horizontal alignment agents such as horizontal alignment agents on the polarizer interface side and horizontal alignment agents on the air interface side. In addition to the above-mentioned components, the composition for forming a liquid crystal layer may also include adhesion modifiers, plasticizers, polymers, etc.

[0189] The coating of the liquid crystal layer forming composition can be performed using known methods such as spin coating, extrusion, gravure coating, die coating, slot coating, rod coating, coater coating, and flexographic printing. After coating the liquid crystal layer forming composition, it is preferable to remove the solvent under conditions where the polymerizable liquid crystal compound contained in the coating layer does not polymerize. Examples of drying methods include natural drying, ventilation drying, heat drying, and reduced pressure drying.

[0190] The polymerization of the polymerizable liquid crystal compound after the coating layer has dried can be carried out using known methods for polymerizing compounds having polymerizable functional groups. Examples of polymerization methods include thermal polymerization and photopolymerization; from the viewpoint of ease of polymerization, photopolymerization is preferred. When using photopolymerization to polymerize the polymerizable liquid crystal compound, it is preferable to use a composition containing a photopolymerization initiator as the liquid crystal layer forming composition. This composition is coated and dried, causing the polymerizable liquid crystal compound contained in the dried film to undergo liquid crystal orientation, and photopolymerization is performed while maintaining this liquid crystal orientation. Examples of photopolymerization initiators include α-carbonyl compounds, azobin ethers, α-hydrocarbon-substituted aromatic azobin compounds, polynuclear quinone compounds, and combinations of triarylimidazolium dimers and p-aminophenyl ketones. The amount of the polymerization initiator used relative to the total solid content of the liquid crystal layer forming composition is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass.

[0191] Photopolymerization can be carried out by irradiating a polymerizable liquid crystal compound that has undergone liquid crystal orientation in a dried film with active energy rays. The active energy rays used for irradiation can be appropriately selected based on the type and amount of polymerizable groups possessed by the polymerizable liquid crystal compound and the type of photopolymerization initiator. Examples include one or more active energy rays selected from visible light, ultraviolet light, laser light, X-rays, alpha rays, beta rays, and gamma rays. From the perspective of easy control of the polymerization reaction and the ability to use widely used photopolymerization apparatus in this field, ultraviolet light is preferred, and the polymerizable liquid crystal compound and photopolymerization initiator are preferably selected in a manner that allows photopolymerization to be carried out using ultraviolet light. During photopolymerization, the polymerization temperature can also be controlled by irradiating the dried film with active energy rays while using a suitable cooling mechanism.

[0192] Examples of light sources that emit active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources that emit light in the wavelength range of 380–440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0193] For ultraviolet radiation intensity, typically, under ultraviolet B (wavelength range 280–310 nm) conditions, it is 100 mW / cm². 2 ~3000mW / cm 2 The intensity of ultraviolet irradiation is preferably within the wavelength range effective for activating cationic polymerization initiators or free radical polymerization initiators. The irradiation time is typically 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds to 1 minute.

[0194] Ultraviolet irradiation can be performed once or in multiple sessions. While this also depends on the polymerization initiator used, the cumulative light intensity at a wavelength of 365 nm is preferably set to 700 mJ / cm². 2 The above is more preferably set at 1100 mJ / cm. 2 The above is further optimized to 1300 mJ / cm. 2 The above-mentioned cumulative light intensity is beneficial for increasing the polymerization rate of the polymerizable liquid crystal compound constituting the liquid crystal layer and for improving heat resistance. The preferred cumulative light intensity at a wavelength of 365 nm is 2000 mJ / cm². 2 Hereinafter, a more preferred setting is 1800 mJ / cm. 2 The following applies. By setting the cumulative light intensity as described above, the coloring of the liquid crystal layer can be suppressed. Furthermore, a cooling process can be performed after ultraviolet irradiation. The cooling temperature can be set to, for example, below 20°C or below 10°C. The cooling time can be set to, for example, 10 seconds or more or 20 seconds or more.

[0195] (Substrate layer)

[0196] The first substrate layer and the second substrate layer (hereinafter sometimes referred to together as "substrate layers") function as support layers, which support the first alignment layer and the second alignment layer, as well as the first liquid crystal layer and the second liquid crystal layer, formed on these substrate layers. The substrate layers are preferably films formed of resin materials.

[0197] As a resin material, resin materials with excellent properties such as transparency, mechanical strength, thermal stability, and tensile strength are used. Specifically, examples include polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth)acrylic acid resins such as poly(meth)acrylate and poly(meth)acrylate; cellulose ester resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyaryl ester resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; polyamide-imide resins; polyetherketone resins; polyphenylene sulfide resins; polyphenylene ether resins; polyvinyl chloride resins; acrylonitrile-butadiene-styrene resins; acrylonitrile-styrene resins; polyvinylidene chloride resins; polyacetal resins; modified polyphenylene ether resins; and their mixtures and copolymers.

[0198] Among these resins, cyclic polyolefin resins, polyester resins, cellulose ester resins and (meth)acrylic resins, or mixtures thereof, are preferred.

[0199] The substrate layer can be a single layer of one resin or a mixture of two or more resins, or it can have a multilayer structure with two or more layers. In the case of a multilayer structure, the resins constituting each layer can be the same or different from each other, or it can be a coating / cured layer such as a hard coating.

[0200] Optional additives may be added to the resin material constituting the film formed from the resin material. Examples of additives include, for instance, ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, anti-blocking agents, pigments, and colorants.

[0201] The thickness of the first substrate layer and the second substrate layer is not particularly limited; however, from the perspective of strength, workability and other operability, it is generally preferred to be 1 to 300 μm or less, more preferably 20 to 200 μm, and even more preferably 30 to 120 μm.

[0202] In the case where the first phase difference layer with the substrate layer has a first orientation layer and the second phase difference layer with the substrate layer has a second orientation layer, in order to improve the adhesion between the first substrate layer and the first orientation layer, and the adhesion between the second substrate layer and the second orientation layer, at least the surface of the first substrate layer on the side where the first orientation layer is formed, and at least the surface of the second substrate layer on the side where the second orientation layer is formed, can be subjected to corona treatment, plasma treatment, flame treatment, etc., or a primer layer can be formed.

[0203] (First bonding layer, second bonding layer, third bonding layer)

[0204] The first, second, and third bonding layers can each be either adhesive-cured layers or adhesive layers. The adhesive-cured layer can be formed using an adhesive composition, and the adhesive layer can be formed using an adhesive composition. The second bonding layer is preferably an adhesive-cured layer. The first bonding layer can be either an adhesive-cured layer or an adhesive layer; however, to increase the Martens hardness H2 of the optical laminate, an adhesive-cured layer is preferred. The third bonding layer is preferably an adhesive layer. The thicknesses of the first, second, and third bonding layers can be the same or different.

[0205] (Adhesive cured layer)

[0206] The adhesive cured layer refers to the adhesive cured layer formed by curing the curing components in the adhesive composition. The thickness of the adhesive cured layer is typically 20 μm or less, preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. If the thickness of the adhesive cured layer is too large, the reaction rate of the curing components in the adhesive composition decreases, and the resistance of the optical laminate to damp heat tends to deteriorate. The thickness of the adhesive cured layer is typically 0.01 μm or more, preferably 0.1 μm or more.

[0207] The storage modulus of the adhesive cured layer is preferably 1200 MPa or more, more preferably 1400 MPa or more, and even more preferably 1900 MPa or more. When the storage modulus of the adhesive cured layer is 1200 MPa or less, the adhesive cured layer is soft and easily deformed, thus easily forming scratches on the surface of the optical laminate 1. When the storage modulus of the adhesive cured layer is large, the adhesive cured layer is hard and not easily deformed, thus making it less prone to scratches on the surface of the optical laminate 1. When the adhesive cured layer is formed from an adhesive composition, by adding a polymer or a component with long molecular chains between functional groups to the adhesive composition, there is a tendency to easily obtain an adhesive cured layer with a small storage modulus. If multifunctional components, especially components with short molecular chains between functional groups, are added, the distance between crosslinking points after curing becomes shorter, and there is a tendency to easily obtain an adhesive cured layer with a large storage modulus. The above-mentioned storage modulus of the adhesive cured layer is a value at a temperature of 23°C and a relative humidity of 55%, which can be measured using the examples described later.

[0208] The adhesive composition used to form the adhesive layer is an adhesive other than a pressure-sensitive adhesive (adhesive), for example, water-based adhesives and active energy radiation-cured adhesives.

[0209] Examples of water-based adhesives include those obtained by dissolving or dispersing polyvinyl alcohol resins in water. There are no particular limitations on the drying method used when using water-based adhesives; for example, methods such as using a hot air dryer or an infrared dryer can be employed.

[0210] Examples of active energy radiation-curable adhesives include solvent-free active energy radiation-curable adhesives that contain curing components that are cured by irradiation with active energy rays such as ultraviolet light, visible light, electron beams, and X-rays. Using solvent-free active energy radiation-curable adhesives improves interlayer adhesion. In contrast, if an active energy radiation-curable adhesive contains a solvent (especially an organic solvent), even if the curing components in the adhesive composition are the same, sufficient adhesion cannot be obtained, and undesirable conditions such as peeling at the ends are likely to occur when the optical laminate is cut to a specified size.

[0211] When using an active energy radiation-curable adhesive, the cured adhesive layer can be formed, for example, by irradiating the coating layer of the active energy radiation-curable adhesive with active energy radiation, thereby curing the curing components. The light source for the active energy radiation can be, for example, a light source that generates ultraviolet light, electron beams, X-rays, etc. Ultraviolet light is preferred. As the ultraviolet light source, a light source with a light emission distribution at a wavelength of 400 nm or less is preferred; examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0212] The intensity of the active energy radiation used to irradiate the coating layer of the active energy radiation-curable adhesive depends on the type of active energy radiation-curable adhesive, but it is preferable to set the irradiation intensity in the wavelength range effective for activating the photopolymerization initiator to 0.1–1000 mW / cm². 2 If the light intensity is too low, the reaction time will be too long. On the other hand, if the light intensity is too high, the adhesive curing layer may yellow due to the heat radiated from the lamp and the heat generated during the polymerization of the curing components, and the deterioration of each layer constituting the optical laminate may occur. Furthermore, the irradiation time of the coating layer should be controlled according to the type of active energy ray-curable adhesive; however, it is preferable that the cumulative light intensity, expressed as the product of light intensity and irradiation time, is 10–5000 mJ / cm². 2 The method of setting is as follows. If the cumulative light amount is too small, the generation of active species from the photopolymerization initiator will be insufficient, and the curing of the resulting adhesive curing layer may become insufficient. On the other hand, if the cumulative light amount is too large, the light irradiation time will become very long, which may be detrimental to improving productivity.

[0213] Examples of active energy ray-curable adhesives include free radical polymeric adhesives, whose curing component contains free radical polymeric compounds, and cationic polymeric adhesives, whose curing component contains cationic polymeric compounds.

[0214] (Free radical polymerizable adhesive)

[0215] Free radical polymerizable adhesives contain free radical polymerizable compounds, which are compounds or oligomers that undergo free radical polymerization reactions and solidify under the influence of active energy rays or heating. Specifically, compounds with olefinic unsaturated bonds can be cited as examples. Examples of compounds with olefinic unsaturated bonds include (meth)acrylic acid compounds having one or more (meth)acryloyl groups within the molecule. Other examples include vinyl compounds such as styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone. Among these, (meth)acrylic acid compounds are preferred free radical polymerizable compounds.

[0216] Examples of (meth)acrylic acid compounds include (meth)acrylate monomers having at least one (meth)acryloyloxy group within the molecule, (meth)acrylamide monomers, and (meth)acrylic acid oligomers having at least two (meth)acryloyl groups within the molecule, obtained by reacting two or more functional group-containing compounds. (Meth)acrylic acid oligomers are preferably (meth)acrylate oligomers having at least two (meth)acryloyloxy groups within the molecule. A single (meth)acrylic acid compound may be used alone, or two or more may be used in combination.

[0217] Examples of (meth)acrylate monomers include monofunctional (meth)acrylate monomers having one (meth)acryloyloxy group in the molecule, difunctional (meth)acrylate monomers having two (meth)acryloyloxy groups in the molecule, and polyfunctional (meth)acrylate monomers having three or more (meth)acryloyloxy groups in the molecule.

[0218] Examples of monofunctional (meth)acrylate monomers include alkyl (meth)acrylates. In alkyl (meth)acrylates, if the alkyl group has 3 or more carbon atoms, it can be either straight-chain or branched. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Alternatively, aralkyl methacrylates such as benzyl methacrylate; terpene alcohol methacrylates such as isobornyl methacrylate; methacrylates with a tetrahydrofurfuryl structure such as tetrahydrofurfuryl methacrylate; cyclohexyl methacrylate, cyclohexyl methacrylate, dicyclopentyl acrylate, dicyclopentenyl methacrylate, and 1,4-cyclohexanediethanol monomethyl methacrylate can also be used. (Meth)acrylates such as acrylates having cycloalkyl groups at the alkyl site; (Meth)acrylate aminoalkyl esters such as N,N-dimethylaminoethyl methacrylate; (Meth)acrylates such as 2-phenoxyethyl methacrylate, dicyclopentenyloxyethyl methacrylate, ethyl carbitol (meth)acrylate, and phenoxy polyethylene glycol (meth)acrylate having ether bonds at the alkyl site are used as monofunctional (meth)acrylate monomers.

[0219] In addition, monofunctional (meth)acrylates having a hydroxyl group at the alkyl site and monofunctional (meth)acrylates having a carboxyl group at the alkyl site can also be used. Specific examples of monofunctional (meth)acrylates having a hydroxyl group at the alkyl site include 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, and pentaerythritol mono(meth)acrylate. Specific examples of monofunctional (meth)acrylates having a carboxyl group at the alkyl site include 2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≈2) mono(meth)acrylate, 1-[2-(meth)acryloyloxyethyl]phthalate, 1-[2-(meth)acryloyloxyethyl]hexahydrophthalate, 1-[2-(meth)acryloyloxyethyl]succinate, 4-[2-(meth)acryloyloxyethyl]trimethacrylate, and N-(meth)acryloyloxy-N',N'-dicarboxymethyl-p-phenylenediamine.

[0220] The preferred monomer for (meth)acrylamide is (meth)acrylamide with a substituent at the N-position, typically an alkyl group. However, it can also form a ring with the nitrogen atom of (meth)acrylamide, which may have an oxygen atom as a ring member in addition to a carbon atom and the nitrogen atom of (meth)acrylamide. Furthermore, at the carbon atom forming the ring, a substituent such as an alkyl group or an oxo (=O) group can be bonded.

[0221] Specific examples of N-substituted (meth)acrylamides include N-alkyl (meth)acrylamides such as N-methyl (meth)acrylamides, N-ethyl (meth)acrylamides, N-isopropyl (meth)acrylamides, N-n-butyl (meth)acrylamides, N-tert-butyl (meth)acrylamides, and N-hexyl (meth)acrylamides; and N,N-dialkyl (meth)acrylamides such as N,N-dimethyl (meth)acrylamides and N,N-diethyl (meth)acrylamides. Furthermore, the N-substituent can also be an alkyl group having a hydroxyl group; examples of this include N-hydroxymethyl (meth)acrylamides, N-(2-hydroxyethyl)(meth)acrylamides, and N-(2-hydroxypropyl)(meth)acrylamides. In addition, specific examples of N-substituted (meth)acrylamides that form the aforementioned 5-membered or 6-membered rings include N-acryloylpyrrolidine, 3-acryloyl-2-oxazolidinone, 4-acryloylmorpholine, N-acryloylpiperidine, and N-methacryloylpiperidine.

[0222] Examples of difunctional (meth)acrylate monomers include alkylene glycol di(meth)acrylates, polyoxyalkylene glycol di(meth)acrylates, halogen-substituted alkylene glycol di(meth)acrylates, di(meth)acrylates of aliphatic polyols, di(meth)acrylates of hydrogenated dicyclopentadiene or tricyclodecanediol, di(meth)acrylates of dioxanediol or dioxanediol, di(meth)acrylates of epoxide alkane adducts of bisphenol A or bisphenol F, and epoxy di(meth)acrylates of bisphenol A or bisphenol F.

[0223] More specific examples of difunctional (meth)acrylate monomers include ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane dimethacrylate, pentaerythritol dimethacrylate, bis(trimethylolpropane)methacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, poly(1,4-butanediol) dimethacrylate, and silicone. Di(meth)acrylate, di(meth)acrylate of neopentyl glycol hydroxypentanoate, 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, 1,3-dioxane-2,5-diyl di(meth)acrylate (also known as: dioxanediol di(meth)acrylate), acetal compound of hydroxypentanoate and trimethylolpropane (chemical name: 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane), di(meth)acrylate of tri(hydroxyethyl)isocyanurate, etc.

[0224] As polyfunctional (meth)acrylate monomers with three or more functions, glycerol tri(meth)acrylate, alkyl glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Poly(meth)acrylates of trifunctional or higher aliphatic polyols are representative examples. Other examples include poly(meth)acrylates of trifunctional or higher halogen-substituted polyols, tri(meth)acrylates of glycerol epoxide alkane adducts, tri(meth)acrylates of trimethylolpropane epoxide alkane adducts, 1,1,1-tris[(meth)acryloyloxyethoxyethoxy]propane, and tri(hydroxyethyl)isocyanurate tri(meth)acrylate.

[0225] On the other hand, examples of (meth)acrylic acid oligomers include urethane (meth)acrylic acid oligomers, polyester (meth)acrylic acid oligomers, and epoxy (meth)acrylic acid oligomers.

[0226] So-called urethane (meth)acrylic acid oligomers are compounds that have an urethane bond (-NHCOO-) and at least two (meth)acryloyl groups in their molecules. Specifically, they can be urethane esterification products of hydroxyl-containing (meth)acrylic acid monomers having at least one (meth)acryloyl group and at least one hydroxyl group in their molecules, respectively, and polyisocyanates; urethane compounds containing terminal isocyanate groups obtained by reacting polyols with polyisocyanates; and urethane esterification products of meth)acrylic acid monomers having at least one (meth)acryloyl group and at least one hydroxyl group in their molecules, respectively.

[0227] The hydroxyl-containing (meth)acrylate monomers used in the above-mentioned carbamate esterification reaction can be, for example, hydroxyl-containing (meth)acrylate monomers, including 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate. Other examples besides hydroxyl-containing (meth)acrylate monomers include N-hydroxyethyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, and other N-hydroxyalkyl (meth)acrylamide monomers.

[0228] Examples of polyisocyanates that can be provided for carbamate reactions with hydroxyl-containing (meth)acrylic acid monomers include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, phenyl diisocyanate, diisocyanates obtained by hydrogenating aromatic isocyanates of these diisocyanates (e.g., hydrogenated toluene diisocyanate, hydrogenated phenyl diisocyanate, etc.), triphenylmethane triisocyanate, dibenzylbenzene triisocyanate, and other di- or tri-isocyanates, as well as polyisocyanates obtained by polymerizing the above-mentioned diisocyanates.

[0229] In addition, as polyols used to prepare urethane compounds containing terminal isocyanate groups by reacting with polyisocyanates, besides aromatic, aliphatic, or alicyclic polyols, polyester polyols, polyether polyols, etc., can also be used. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, bis(trimethylolpropane), pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerol, hydrogenated bisphenol A, etc.

[0230] Polyester polyols are substances obtained through the dehydration condensation reaction of the aforementioned polyols with polycarboxylic acids or their anhydrides. Examples of polycarboxylic acids or their anhydrides that can become anhydrides include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itaconic acid (anhydride), trimellitic acid (anhydride), pyromellitic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, and hexahydrophthalic acid (anhydride), etc.

[0231] In addition to polyalkylene glycols, polyoxyalkylene modified polyols obtained by reacting the aforementioned polyols or dihydroxybenzenes with epoxides can also be cited as examples of polyether polyols.

[0232] Polyester (meth)acrylic acid oligomers are compounds that have an ester bond and at least two (meth)acryloyl groups (typically (meth)acryloyloxy groups) within their molecules. Specifically, they can be obtained through a dehydration condensation reaction using (meth)acrylic acid, a polycarboxylic acid or its anhydride, and a polyol. Examples of polycarboxylic acids or their anhydrides used in the dehydration condensation reaction, indicated by adding "(anhydride)" to the substance that can become an anhydride, include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itaconic acid (anhydride), trimellitic acid (anhydride), pyromellitic acid (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, etc. In addition, examples of polyols used in dehydration condensation reactions include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, bis(trimethylolpropane), pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerol, and hydrogenated bisphenol A.

[0233] Epoxy (meth)acrylic acid oligomers can be obtained, for example, by the addition reaction of polyglycidyl ethers with (meth)acrylic acid, and have at least two (meth)acryloyloxy groups in the molecule. Examples of polyglycidyl ethers used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether.

[0234] Free radical polymerizable adhesives may contain both free radical polymerizable compounds and cationic polymerizable compounds found in cationic polymerizable adhesives (described later). When the total amount of curable components in the free radical polymerizable adhesive is set at 100% by weight, the content of cationic polymerizable compounds (or their total content in the case of two or more cationic polymerizable compounds) is preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less, within the 100% by weight of polymerizable components.

[0235] Free radical polymerizable adhesives preferably contain curable components such as free radical polymerizable compounds, and also include a photoradical polymerization initiator. A photoradical polymerization initiator is a substance that initiates the polymerization reaction of a free radical curable compound upon irradiation by active energy rays such as visible light, ultraviolet light, X-rays, or electron beams. A single photoradical polymerization initiator can be used alone, or two or more can be used in combination.

[0236] Specific examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, biphenyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-propanone, 2-methyl-1-[4-(methylthio)phenyl-2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, etc., acetophenone-based initiators; benzophenone, 4-chlorobenzophenone, 4,4'-diaminobenzophenone, etc., benzoin ether-based initiators; benzoin propyl ether, benzoin ethyl ether, etc., thioxanthone-based initiators; and xanthones, fluorenone, camphorquinone, benzaldehyde, anthraquinone.

[0237] The amount of photoradical polymerization initiator relative to 100 parts by weight of the free radical polymerizable compound is typically 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight. By incorporating 0.5 parts by weight or more of photoradical polymerization initiator, the free radical polymerizable compound can be fully cured, imparting high mechanical and adhesive strength to the resulting optical laminate. On the other hand, if the amount is too large, the durability of the optical laminate may decrease.

[0238] Free radical polymerizable adhesives may contain other additives as needed. Specific examples of additives include ion scavengers, antioxidants, chain transfer agents, polymerization accelerators (polyols, etc.), sensitizers, sensitizing aids, light stabilizers, tackifiers, thermoplastic resins, fillers, flow modifiers, plasticizers, defoamers, leveling agents, silane coupling agents, pigments, antistatic agents, and UV absorbers. Examples of ion scavengers include powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based, and mixtures thereof inorganic compounds; examples of antioxidants include hindered phenolic antioxidants.

[0239] (Cationic polymeric adhesive)

[0240] Cationic polymeric adhesives contain cationic polymeric compounds, which are compounds or oligomers that undergo cationic polymerization and curing under the influence of active energy rays such as ultraviolet light, visible light, electron beams, and X-rays. Examples include epoxy compounds, oxobutane compounds, and vinyl compounds. Among these, epoxy compounds are preferred. An epoxy compound is a compound having one or more, preferably two or more, epoxy groups within its molecule. An epoxy compound can be used alone or in combination with two or more. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. From the viewpoints of weather resistance, curing speed, and adhesion, epoxy compounds preferably include alicyclic epoxy compounds and aliphatic epoxy compounds, and more preferably alicyclic epoxy compounds.

[0241] Alicyclic epoxides are compounds that have one or more epoxy groups bonded to an alicyclic ring within the molecule. The term "epoxy group bonded to an alicyclic ring" refers to the bridging oxygen atom -O- in the structure shown in formula (I) below. In formula (I) below, m is an integer from 2 to 5.

[0242] [Chemistry 1]

[0243]

[0244] Compounds in which one or more hydrogen atoms are removed from (CH2)m of formula (I) above and bonded to other chemical structures can become alicyclic epoxides. One or more hydrogen atoms in (CH2)m can also be appropriately substituted by straight-chain alkyl groups such as methyl or ethyl.

[0245] Among them, alicyclic epoxy compounds with cyclopentane oxide structures (structures where m=3 in formula (I) above) and cyclohexane oxide structures (structures where m=4 in formula (I) above) have high glass transition temperatures and are also advantageous in terms of interlayer adhesion. Specific examples of alicyclic epoxy compounds are given below. Here, the compound name is given first, followed by the corresponding chemical formula, using the same symbols for both the compound name and its corresponding chemical formula.

[0246] A: 3,4-Epoxycyclohexanecarboxylic acid, 3,4-epoxycyclohexylmethyl ester

[0247] B: 3,4-Epoxy-6-methylcyclohexanecarboxylic acid, 3,4-epoxy-6-methylcyclohexylmethyl ester

[0248] C: Ethylenebis(3,4-epoxycyclohexanecarboxylate),

[0249] D: Bis(3,4-epoxycyclohexylmethyl) adipate,

[0250] E: Bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate,

[0251] F: Diethylene glycol bis(3,4-epoxycyclohexylmethyl ether)

[0252] G: Ethylene glycol bis(3,4-epoxycyclohexylmethyl ether),

[0253] H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]cosicosane,

[0254] I: 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane,

[0255] J: 4-Vinylcyclohexene dioxide,

[0256] K: Limonene dioxide,

[0257] L: Bis(2,3-epoxycyclopentyl) ether,

[0258] M: dicyclopentadiene dioxide (original Japanese text: ジシクロペンタジエンジオキサイド).

[0259] [Chemistry 2]

[0260]

[0261] [Chemistry 3]

[0262]

[0263] Aromatic epoxy compounds are compounds that have an aromatic ring and an epoxy group within their molecules. Specific examples include bisphenol-type epoxy compounds or their oligomers, such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether; linear phenolic epoxy resins, such as phenol linear phenolic epoxy resin, cresol linear phenolic epoxy resin, and hydroxybenzaldehyde phenol linear phenolic epoxy resin; multifunctional epoxy compounds, such as 2,2',4,4'-tetrahydroxydiphenylmethane glycidyl ether and 2,2',4,4'-tetrahydroxybenzophenone glycidyl ether; and multifunctional epoxy resins, such as epoxidized polyvinylphenol.

[0264] Hydrogenated epoxy compounds are glycidyl ethers of polyols having alicyclic rings. They can be obtained by selectively hydrogenating the aromatic ring of an aromatic polyol under pressure in the presence of a catalyst, and then etherifying the resulting hydrogenated polyhydroxy compound with glycidyl ether. Specific examples of aromatic polyols include bisphenol-type compounds such as bisphenol A, bisphenol F, and bisphenol S; linear phenolic resins such as phenol, cresol, and hydroxybenzaldehyde; and multifunctional compounds such as tetrahydroxydiphenylmethane, tetrahydroxybenzophenone, and polyvinylphenol. By hydrogenating the aromatic ring of an aromatic polyol and reacting epichlorohydrin with the resulting alicyclic polyol, glycidyl ethers can be prepared. A preferred compound among hydrogenated epoxy compounds is the diglycidyl ether of hydrogenated bisphenol A.

[0265] Aliphatic epoxy compounds are compounds that have at least one ethylene oxide ring (a 3-membered cyclic ether) bonded to an aliphatic carbon atom within their molecule. Examples include monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; difunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether; trifunctional or more functional epoxy compounds such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; and epoxy compounds such as 4-vinylcyclohexene dioxide and limonene dioxide, which have one epoxy group directly bonded to an alicyclic ring and an ethylene oxide ring bonded to an aliphatic carbon atom. From the viewpoint of adhesion between the polarizing film and the protective film, difunctional epoxy compounds (also called aliphatic diesters) with two ethylene oxide rings bonded to aliphatic carbon atoms within their molecule are preferred. The suitable aliphatic diepoxide can be represented, for example, by the following formula (II).

[0266] [Chemistry 4]

[0267]

[0268] In the above formula (II), Y is an alkylene group with 2 to 9 carbon atoms, an alkylene group with 4 to 9 carbon atoms containing ether bonds, or a divalent hydrocarbon group with 6 to 18 carbon atoms having an alicyclic structure.

[0269] Specifically, the aliphatic diepoxide compound represented by formula (II) above is a diglycidyl ether of an alkyl diol, a diglycidyl ether of an oligoalkylene diol with a repeat number up to about 4, or a diglycidyl ether of an alicyclic diol.

[0270] The following are specific examples of glycols capable of forming the aliphatic diepoxide compound shown in formula (II) above. Examples of alkyl glycols include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, and 1,9-nonanediol.

[0271] As oligomeric alkylene glycols, they include diethylene glycol, triethylene glycol, tetraethylene glycol, and dipropylene glycol. As alicyclic glycols, they include cyclohexanediol and cyclohexanediol.

[0272] Oxycyclobutane compounds, as cationic polymerizable compounds, are compounds containing one or more oxycyclobutane rings (oxycyclobutane groups) within their molecules. Specific examples include 3-ethyl-3-hydroxymethyloxycyclobutane (also known as oxycyclobutanol), 2-ethylhexyloxycyclobutane, 1,4-bis[((3-ethyloxycyclobutan-3-yl)methoxy}methyl]benzene (also known as phenylenedimethylenedioxycyclobutane), 3-ethyl-3[{(3-ethyloxycyclobutan-3-yl)methoxy)methyl]oxycyclobutane, 3-ethyl-3-(phenoxymethyl)oxycyclobutane, and 3-(cyclohexyloxy)methyl-3-ethyloxycyclobutane. Oxycyclobutane compounds can be used as the main component of cationic polymerizable compounds or in combination with epoxy compounds. By combining oxycyclobutane compounds, the curing speed and adhesion can be improved.

[0273] Vinyl compounds capable of becoming cationic polymers include aliphatic or alicyclic vinyl ether compounds. Specific examples include alkyl or alkenyl vinyl ethers with 5 to 20 carbon atoms, such as n-pentyl vinyl ether, isopentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, and oleyl vinyl ether; hydroxyl-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, and 4-hydroxybutyl vinyl ether; vinyl ethers of monools containing aliphatic or aromatic rings such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, and benzyl vinyl ether; and glycerol monovinyl ether, 1,4-... Mono- and polyvinyl ethers of polyols such as butanediol monovinyl ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol tetravinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane divinyl ether, 1,4-dihydroxymethylcyclohexane monovinyl ether, and 1,4-dihydroxymethylcyclohexane divinyl ether; polyalkylene glycol mono- and polyvinyl ethers such as diethylene glycol divinyl ether, triethylene glycol divinyl ether, and diethylene glycol monobutyl monovinyl ether; and other vinyl ethers such as glycidyl vinyl ether and ethylene glycol vinyl ether methacrylate. Vinyl compounds can be used as the main component of cationic polymerizable compounds, or in combination with epoxy compounds, or epoxy compounds and oxetane compounds. Combining vinyl compounds can sometimes improve curing speed and reduce the viscosity of the adhesive.

[0274] Cationic polymeric adhesives may contain curing components other than cationic polymeric compounds and free radical polymeric compounds. Examples of other curing components include lactone compounds, cyclic acetal compounds, cyclic sulfide compounds, and spirocyclic orthoester compounds.

[0275] When the total amount of curing components contained in the cationic polymeric adhesive is set to 100% by weight, the content of the cationic polymeric compound (the total content of two or more cationic polymeric compounds) is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 100% by weight.

[0276] Cationic polymerizable adhesives preferably contain a photocationic polymerization initiator in addition to curing components such as cationic polymerizable compounds. A photocationic polymerization initiator is a substance that generates cationic species or Lewis acids upon irradiation by active energy rays such as visible light, ultraviolet light, X-rays, or electron beams, and initiates the polymerization reaction of the cationic curable compound. Because the photocationic polymerization initiator acts as a catalyst under light irradiation, it exhibits excellent storage stability and workability even when mixed into the photocationic curable compound. Examples of compounds that generate cationic species or Lewis acids upon irradiation by active energy rays include, for example, aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, and iron-aromatic complexes.

[0277] Aromatic iodonium salts are compounds containing a diaryl iodonium cation, of which diphenyliodonium cation is commonly cited.

[0278] Aromatic sulfonium salts are compounds containing a triarylsulfonium cation, such as triphenylsulfonium cation and 4,4'-bis(diphenylsulfonyl)diphenyl sulfide cation. Aromatic diazonium salts are compounds containing a diazonium cation, such as benzenediazonium cation. Additionally, iron-aromatic complexes are typically cyclopentadienyl iron(II)aromatic cation complexes.

[0279] The cations and anions shown above pair to form photocationic polymerization initiators. Examples of anions that constitute photocationic polymerization initiators include specific phosphorus-based anions [(Rf]]. n PF 6-n ]- Hexafluorophosphate anion PF6 - SbF6, anion of hexafluoroantimonate - The pentafluorohydroxyantimonate anion SbF5(OH) - AsF6 hexafluoroarsenate anion - Tetrafluoroborate anion BF4 - Tetra(pentafluorophenyl)borate anion B(C6F5)4 - Etc. Among these, from the viewpoint of the curability of the cationic polymerizable compound and the safety of the resulting adhesive layer, a special phosphorus-based anionic [(Rf)] is preferred. n PF 6-n ] - hexafluorophosphate anion PF6 - .

[0280] Photocationic polymerization initiators can be used alone or in combination of two or more. Among them, aromatic sulfonate salts are preferred because they also have ultraviolet absorption characteristics in the wavelength region around 300 nm, thus providing cured products with excellent curability and good mechanical and adhesive strength.

[0281] The amount of photocationic polymerization initiator relative to 100 parts by weight of the cationic polymerizable compound is typically 0.5 to 10 parts by weight, preferably 6 parts by weight or less. By incorporating 0.5 parts by weight or more of photocationic polymerization initiator, the cationic polymerizable compound can be fully cured, imparting high mechanical and adhesive strength to the resulting polarizing plate. On the other hand, if the amount is too large, the ionic substances in the cured product increase, thereby increasing the hygroscopicity of the cured product and potentially reducing the durability of the polarizing plate.

[0282] Cationic polymeric adhesives may contain other additives as needed. Examples of additives that can be included in free radical polymeric adhesives, as described above, include those additives.

[0283] (Adhesive layer)

[0284] An adhesive layer refers to a layer formed using an adhesive composition containing an adhesive. In this specification, "adhesive" refers to a substance that exhibits adhesive properties by adhering itself to a substrate such as a polarizing plate or a liquid crystal layer; this is known as a pressure-sensitive adhesive. Furthermore, the active energy-curing adhesive described later can have its crosslinking degree and adhesive strength adjusted by irradiation with energy rays.

[0285] The thickness of the adhesive layer is preferably 3 μm or more, more preferably 5 μm or more. Furthermore, the thickness of the adhesive layer is preferably 40 μm or less, more preferably 30 μm or less. It should be noted that the above-mentioned upper and lower limits can be combined arbitrarily.

[0286] As an adhesive, conventionally known adhesives with excellent optical transparency can be used without particular limitation, such as adhesives with base polymers like acrylic, urethane, silicone, and polyvinyl ether. Additionally, active energy radiation-cured adhesives and thermosetting adhesives can also be used. Among these, adhesives with acrylic resins as base polymers that exhibit excellent transparency, adhesion, re-peelability (hereinafter also referred to as reprocessability), weather resistance, and heat resistance are suitable. The adhesive layer preferably consists of the reaction product of an adhesive composition containing (meth)acrylic resin, a crosslinking agent, and a silane compound, but other components may also be included.

[0287] Adhesive layers can be formed using active energy-curing adhesives. These adhesives incorporate ultraviolet-curable compounds such as polyfunctional acrylates into the adhesive composition, and are cured by irradiation with ultraviolet light after the adhesive layer is formed, thus creating a harder adhesive layer. Active energy-curing adhesives possess the property of curing upon irradiation with energy rays such as ultraviolet light or electron beams. They retain adhesive properties even before irradiation with energy rays, thus enabling them to adhere tightly to substrates such as optical films and liquid crystal layers, and allowing for adjustment of adhesion strength through curing via energy irradiation.

[0288] Active energy-curing adhesives generally contain acrylic adhesives and energy-ray polymerizable compounds as the main components. They usually also contain crosslinking agents, and photoinitiators, photosensitizers, etc., may be added as needed.

[0289] Example

[0290] The present invention will be further described in detail below with reference to embodiments and comparative examples; however, the present invention is not limited to these examples. Unless otherwise specified, “%” and “parts” in the embodiments and comparative examples refer to mass percentage and mass parts.

[0291] In order to obtain the optical laminates described in the Examples, Comparative Examples and Reference Examples, each material was prepared as follows.

[0292] [Fabrication of a linear polarizing layer]

[0293] A 30 μm thick polyvinyl alcohol (PVA) film (average degree of polymerization approximately 2400, saponification degree ≥ 99 mol%) was uniaxially stretched longitudinally to approximately 5 times using a dry stretching method. While maintaining tension, it was then immersed in pure water at 60°C for 1 minute, followed by immersion in an aqueous solution at 28°C with an iodine / potassium iodide / water weight ratio of 0.05 / 5 / 100 for 60 seconds. Subsequently, it was immersed in an aqueous solution at 72°C with a potassium iodide / boric acid / water weight ratio of 8.5 / 8.5 / 100 for 300 seconds. Immediately afterward, it was washed with pure water at 26°C for 20 seconds and then dried at 65°C to obtain a 12 μm thick linearly polarized layer with iodine adsorbed and oriented on the PVA film.

[0294] [Preparation of water-based adhesives]

[0295] A polyvinyl alcohol aqueous solution was prepared by dissolving 3 parts of carboxyl-modified polyvinyl alcohol (KL-318 manufactured by Kuraray Co., Ltd.) relative to 100 parts of water. A water-soluble polyamide epoxy resin (Sumirez Resin 650(30) manufactured by Taoka Chemical Co., Ltd., with a solid content of 30% by weight) was mixed into the obtained aqueous solution at a ratio of 1.5 parts relative to 100 parts of water to obtain a water-based adhesive.

[0296] [Preparation of adhesive layer (a) with release film on both sides]

[0297] To a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet, 95.0 parts of n-butyl acrylate, 4.0 parts of acrylic acid, 1.0 part of 2-hydroxyethyl acrylate, 200 parts of ethyl acetate, and 0.08 parts of 2,2′-azobisisobutyronitrile were added. The air in the reaction vessel was replaced with nitrogen. Under a nitrogen atmosphere, the reaction solution was heated to 60°C with stirring and allowed to react for 6 hours, then cooled to room temperature. The weight-average molecular weight of a portion of the resulting solution was determined, confirming the formation of a (meth)acrylate polymer with a molecular weight of 1.8 million.

[0298] 100 parts of the (meth)acrylate polymer obtained in the above process (solid content conversion value; the same below), 1.5 parts of trimethylolpropane-modified toluene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate (registered trademark) L") as an isocyanate-based crosslinking agent, 0.30 parts of 3-epoxypropoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM403") as a silane coupling agent, 7.5 parts of ethoxylated isocyanurate triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name "A-9300") as a UV-curable compound, and 0.5 parts of 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (manufactured by BASF Corporation, Irgacure (registered trademark) 907) as a photopolymerization initiator are mixed, stirred thoroughly, and diluted with ethyl acetate to obtain a coating solution of the adhesive composition.

[0299] On the release surface (release layer) of the release film (LINTEC Corporation: SP-PLR382190), the coating solution obtained above is applied using a coater to a thickness of 5 μm after drying. The coating is then dried at 100°C for 1 minute to form a dried coating layer. On the side of the dried coating layer opposite to the side with the release film, another release film (LINTEC Corporation: SP-PLR381031) is then applied. Subsequently, using a UV irradiation device with a conveyor belt (Fusion UV Systems, using a D-type bulb), the dried coating layer is irradiated with UV light (500 mW / cm²) through spacers. 2 Cumulative light intensity 500mJ / cm 2 An adhesive layer (a) with spacers on both sides is obtained by forming an adhesive layer (a) from the above-mentioned dried coating layer.

[0300] [Preparation of the first retardation layer with a substrate layer]

[0301] A first retardation layer having a first substrate layer as a transparent substrate and a first retardation layer is prepared. The first retardation layer is a laminate of a first alignment layer and a first liquid crystal layer obtained by curing a nematic liquid crystal compound, and has a 1 / 4 wavelength retardation characteristic. Furthermore, the thickness of the first retardation layer is 2 μm.

[0302] [Preparation of UV-curable adhesive (b)]

[0303] A UV-curable adhesive (b) was prepared by mixing 80.0 parts of dipentaerythritol hexaacrylate (A-DPH manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), 20.0 parts of polyethylene glycol di(meth)acrylate (A-200 manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), and 3.0 parts of Darocur 1173 (Darocur 1173 manufactured by BASF) as a photopolymerization initiator. The storage modulus of the cured film obtained by curing the UV-curable adhesive (b) was measured at 23°C and 55% relative humidity using the following steps, and the result was 2000 MPa.

[0304] [Determination of energy storage modulus]

[0305] On one side of a polyethylene terephthalate (PET) film (ESTER Film E7002, manufactured by Toyobo Co., Ltd.), a UV-curable adhesive was applied using a coating machine (bar coater, manufactured by Daiichi Rika Co., Ltd.), and a Fusion UV Systems D lamp was used to accumulate a light dose of 1500 mJ / cm². 2UV light was used to cure the UV-curable adhesive (b). The adhesive was cut into 1cm x 8cm pieces, and the PET film was peeled off to obtain individual cured films of the UV-curable adhesive (b). The resulting individual films were held in a tensile testing machine (AUTOGRAPHAG-1S, manufactured by Shimadzu Corporation) with the long side in the stretching direction, with clamps spaced 5cm apart. The films were stretched at 10mm / min in an environment of 23°C and 55% relative humidity. The elastic modulus was calculated using data processing software (TRAPEZIUM2, manufactured by Shimadzu Corporation) based on the initial straight line of the stress-strain curve.

[0306] The following steps are used to evaluate the second phase difference layer and the optical stack.

[0307] [Determination of the Martens hardness H1 of the second phase retardation layer]

[0308] The second retardation layer with a substrate layer obtained in the Examples, Comparative Examples, and Reference Examples was cut into 40mm × 40mm pieces. On the second retardation layer side, the surface of the adhesive layer (a) exposed by peeling off one of the release films of the two adhesive layers (a) with release films on both sides obtained above was adhered. Next, the release film of the other adhesive layer (a) was peeled off, and the exposed surface of the adhesive layer (a) was adhered to a 40mm × 40mm glass plate. Then, the second substrate layer of the second retardation layer with the substrate layer was peeled off to obtain the test sample (1). In the test sample (1), glass, adhesive layer (a), and second retardation layer are sequentially stacked. In an atmosphere of 23°C and 55% relative humidity, the surface of the second phase difference layer of the test sample (1) was subjected to a load of 1 mN / 5 seconds using an ultra-micro hardness tester (FISCHERSCOPE HM2000: manufactured by FISCHER INSTRUMENTS). The creep time (the time to maintain the 1 mN load) was set to 5 s, and the measured martensitic hardness was set as the martensitic hardness H1 of the second phase difference layer.

[0309] [Determination of the Martens hardness H2 of optical laminates]

[0310] The optical laminates obtained in the Examples, Comparative Examples, and Reference Examples were cut into 40mm × 40mm pieces. On the polarizer side (surface of the protective film) of the optical laminate, the surface of the adhesive layer (a) exposed by peeling off one of the release films was attached to the adhesive layer (a) with release films on both sides obtained above. Next, the release film of the other side attached to the adhesive layer (a) was peeled off, and the exposed surface of the adhesive layer (a) was attached to a 40mm × 40mm glass plate to obtain the test sample (2). In the test sample (2), glass, adhesive layer (a), and optical laminate are stacked in sequence, and the outer surface of the optical laminate side of the test sample (2) is the surface of the second phase difference layer side. In an atmosphere of 23°C and 55% relative humidity, the surface of the second phase difference layer side of the test sample (2) was subjected to a load of 1 mN / 5 seconds using an ultra-micro hardness tester (FISCHERSCOPEHM2000: manufactured by FISCHER INSTRUMENTS). The creep time (the time to maintain the 1 mN load) was set to 5 s, and the measured martensitic hardness was set as the martensitic hardness H2 of the optical laminate.

[0311] [Scratch Test]

[0312] The optical laminates obtained in the Examples, Comparative Examples, and Reference Examples were cut into 100mm × 100mm pieces. On the polarizing plate side (surface of the protective film) of the optical laminate, the surface of the adhesive layer (a) exposed by peeling off one of the release films was attached to the adhesive layer (a) with release films on both sides obtained above. The release film on the other side of the adhesive layer (a) was peeled off, and the exposed surface of the adhesive layer (a) was attached to a 100mm × 100mm glass plate to obtain the test sample (3). In an atmosphere of 23°C and 55% relative humidity, the surface of the second phase difference layer side of the test sample (3) was covered with a metal block having a square plane with a bottom surface of 25mm × 25mm using BEMCOT M-3II (manufactured by Asahi Kasei Corporation) as a nonwoven fabric. The bottom surface of the metal block (the bottom surface covered by the nonwoven fabric) was subjected to a load of 250g / cm². 2 While pressing the sample (3) against the surface of the second phase difference layer, move it back and forth in a straight line for 10 times at a speed of 5 m / min, covering a distance of 7 cm. Then, visually observe the condition of the surface of the second phase difference layer. Visually count the number of scratches in a 20 mm wide area orthogonal to the back-and-forth direction of the metal block in the area passing through the nonwoven fabric, and set this as the number of scratches [scratches / 20 mm]. Evaluate using the following criteria. It should be noted that all scratches generated in the sample (3) are straight scratches along the back-and-forth direction of the nonwoven fabric.

[0313] A: No scars are visible at all or almost entirely.

[0314] B: More than a dozen scars were observed (more than 10 to less than 20 [scars / 20mm]).

[0315] C: Dozens of scars were observed (more than 20 to 30 [scars / 20mm]).

[0316] D: Many (more than 30 [scratches / 20mm]) scratches were observed.

[0317] [Example 1]

[0318] (Making of a polarizing plate with a protective film)

[0319] On one side of the linear polarizing layer (12 μm thick) obtained above, the aqueous adhesive prepared above is coated, and a protective layer (a triacetyl cellulose (TAC) film manufactured by Konica Minolta Co., Ltd. (20 μm thick, in-plane phase difference at 590 nm: 1.2 nm, thickness-direction phase difference at 590 nm: 1.3 nm)) is bonded. On the other side of the linear polarizing layer, the aqueous adhesive prepared above is coated, and a surface-treated protective layer (a COP film with a 3 μm thick coating of a surface-treated agent manufactured by Nippon Paper Co., Ltd. on a cyclic olefin resin (COP) film manufactured by Zeon Co., Ltd. (25 μm thick, in-plane phase difference at 590 nm: 140 nm)) is bonded. The film is then dried at 80°C for 5 minutes, thereby obtaining a polarizing plate with protective layers on both sides of the linear polarizing layer. A protective film is attached to the side of the surface-treated protective layer (COP film with surface treatment layer) of the obtained polarizing plate, and cured at 40°C for 168 hours to obtain a polarizing plate with a protective film.

[0320] (Fabrication of a polarizing plate with an adhesive layer)

[0321] On the polarizing plate side (protective layer side of TAC film) of the obtained polarizing plate with protective film, the surface of the adhesive layer (a) exposed by peeling off one of the release films of the two adhesive layers (a) with release films on both sides obtained above is attached. Then, the release film of the other side is peeled off to obtain a polarizing plate with adhesive layer. The polarizing plate with adhesive layer has a protective film, a polarizing plate and adhesive layer (a) in sequence.

[0322] (Preparation of the second phase retardation layer with a substrate layer)

[0323] A composition for forming an orientation layer was prepared by dissolving 10.0 parts of polyethylene glycol di(meth)acrylate, 10.0 parts of trimethylolpropane triacrylate, 10.0 parts of 1,6-hexanediol di(meth)acrylate, and 1.50 parts of Irgacure 907 as a photopolymerization initiator in 70.0 parts of methyl ethyl ketone as a solvent.

[0324] A composition for forming a liquid crystal layer was prepared by dissolving 20.0 parts of a photopolymerizable nematic liquid crystal compound and 1.0 part of Irgacure 907 as a photopolymerization initiator in 80.0 parts by weight of propylene glycol monomethyl ether acetate as a solvent.

[0325] A corona treatment was applied to one side of the second substrate layer (a strip-shaped cyclic olefin resin film with a thickness of 20 μm). The alignment layer forming composition prepared above was then applied to the corona-treated side using a bar coater to form a first coating layer. After heat treatment of the first coating layer at 80°C for 60 seconds, ultraviolet light was applied to polymerize and cure the alignment layer forming composition, forming a second alignment layer with a thickness of 1.8 μm on the second substrate layer. The liquid crystal layer forming composition prepared above was then applied to the second alignment layer to form a second coating layer. After heat treatment of the second coating layer at 80°C for 60 seconds, ultraviolet light was applied to polymerize and cure the liquid crystal layer forming composition, forming a second liquid crystal layer with a thickness of 0.7 μm on the second alignment layer. Thus, a second retardation layer (1) with a substrate layer was obtained, sequentially comprising a second substrate layer, a second alignment layer, and a second liquid crystal layer. The Martens hardness H1 of the second retardation layer (1) with the substrate layer was measured. The results are shown in Table 1.

[0326] (Fabrication of optical laminate (1))

[0327] Corona treatment was performed on the first phase difference layer side of the first phase difference layer with substrate layer and the second phase difference layer (1) with substrate layer prepared above. On one of the corona-treated surfaces, the ultraviolet-curable adhesive (b) prepared above was coated. After the first phase difference layer with substrate layer and the second phase difference layer (1) with substrate layer were bonded together, ultraviolet light was irradiated to cure the ultraviolet-curable adhesive (b) to form an adhesive cured layer as the second bonding layer. Thus, a laminate (1) was obtained in which the first substrate layer, the first phase difference layer (first alignment layer, first liquid crystal layer), the second bonding layer (adhesive cured layer), the second phase difference layer (second liquid crystal layer, second alignment layer) and the second substrate layer were sequentially stacked.

[0328] The exposed surface of the laminate (1) obtained above, which is exposed due to the peeling of the first substrate layer, is bonded to the adhesive layer (a) of the polarizer with the adhesive layer. Then, the second substrate layer is peeled off, thereby obtaining the optical laminate (e1). The peeling interface when peeling off the first substrate layer is between the first substrate layer and the first alignment layer, and the peeling interface when peeling off the second substrate layer is between the second alignment layer and the second liquid crystal layer. The optical laminate (e1) sequentially includes a protective film, a polarizer, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive curing layer), and a second liquid crystal layer. The martensitic hardness H2 of the obtained optical laminate (e1) was measured, and a scratch test was performed. The results are shown in Table 1.

[0329] [Example 2]

[0330] A polarizing plate with a protective film and a laminate (1) were prepared using the steps described in Example 1. The polarizing plate side (protective layer side of the TAC film) of the polarizing plate with the protective film was bonded to the exposed surface of the laminate (1) exposed by peeling off the first substrate layer using the UV-curable adhesive (b) prepared above. The UV-curable adhesive (b) was cured by irradiation with ultraviolet light to form an adhesive-cured layer as the first bonding layer. Otherwise, the steps were the same as in Example 1 to obtain an optical laminate (e2). The optical laminate (e2) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive-cured layer), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive-cured layer), and a second liquid crystal layer. The martensitic hardness H2 of the obtained optical laminate (e2) was measured, and a scratch test was performed. The results are shown in Table 1.

[0331] [Comparative Example 1]

[0332] Except for the laminate (2) obtained by bonding the first phase retardation layer with the substrate layer and the second phase retardation layer (1) with the substrate layer using the adhesive layer (a) with release film on both sides obtained above, the same steps as in Example 1 were followed to obtain an optical laminate (c1). The obtained optical laminate (c1) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive layer (a)), and a second liquid crystal layer. The martensitic hardness H2 of the obtained optical laminate (c1) was measured, and a scratch test was performed. The results are shown in Table 1.

[0333] [Example 3]

[0334] Except for not subjecting one side of the second substrate layer (a strip-shaped cyclic olefin resin film with a thickness of 20 μm) to corona treatment, the same steps as those described in Example 1 were followed to obtain the second retardation layer (2) with the substrate layer. Using the obtained second retardation layer (2) with the substrate layer and the laminate (1) prepared using the steps described in Example 1, the same steps as in Example 1 were followed to obtain the optical laminate (e3). The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (e3) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive curing layer), a second liquid crystal layer, and a second alignment layer. Using the obtained second phase difference layer (2) with a substrate layer, the martensitic hardness H1 of the second phase difference layer was measured, the martensitic hardness H2 of the optical laminate (e3) was measured, and a scratch test was performed.

[0335] The results are shown in Table 1.

[0336] [Comparative Example 2]

[0337] Except for preparing the second retardation layer (2) with a substrate layer using the steps described in Example 3, preparing the laminate (2) using the steps described in Comparative Example 1, and using them, the optical laminate (c2) was obtained by following the same steps as in Example 1. The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (c2) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive layer (a)), a second liquid crystal layer, and a second alignment layer. The martensitic hardness H2 of the obtained optical laminate (c2) was measured, and a scratch test was performed. The results are shown in Table 1.

[0338] [Reference Example 1]

[0339] Except for setting the thickness of the second alignment layer formed on the second substrate layer to 2.2 μm, the same steps as those described in Example 3 for fabricating the second retardation layer (2) with a substrate layer were performed to obtain the second retardation layer (3) with a substrate layer. Except for using the obtained second retardation layer (3) with a substrate layer and the laminate (2) fabricated using the steps described in Comparative Example 1, the same steps as in Example 1 were followed to obtain the optical laminate (r1). The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (r1) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive layer (a)), a second liquid crystal layer, and a second alignment layer. The martensitic hardness H1 of the second retardation layer was measured using the obtained second retardation layer (3) with a substrate layer, and the martensitic hardness H2 of the obtained optical laminate (r1) was measured to perform a scratch test. The results are shown in Table 1.

[0340] [Reference Example 2]

[0341] Except for preparing the second retardation layer (3) with a substrate layer using the steps described in Reference Example 1, preparing the laminate (1) using the steps described in Example 1, and using them, the optical laminate (r2) was obtained by following the same steps as in Example 1. The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (r2) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive curing layer), a second liquid crystal layer, and a second alignment layer. The martensitic hardness H2 of the obtained optical laminate (r2) was measured, and a scratch test was performed. The results are shown in Table 1.

[0342] [Reference Example 3]

[0343] Except for setting the thickness of the second alignment layer formed on the second substrate layer to 5.0 μm, the same steps as those described in Example 3 for fabricating the second retardation layer (2) with a substrate layer were followed to obtain the second retardation layer (4) with a substrate layer. Except for using the obtained second retardation layer (4) with a substrate layer and the laminate (2) fabricated using the steps described in Comparative Example 1, the same steps as in Example 1 were followed to obtain the optical laminate (r3). The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (r3) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive layer (a)), a second liquid crystal layer, and a second alignment layer. The martensitic hardness H1 of the second retardation layer was measured using the obtained second retardation layer (4) with a substrate layer, and the martensitic hardness H2 of the obtained optical laminate (r3) was measured to perform a scratch test. The results are shown in Table 1.

[0344] [Reference Example 4]

[0345] Except for preparing the second retardation layer (4) with a substrate layer using the steps described in Reference Example 3, preparing the laminate (1) using the steps described in Example 1, and using them, the optical laminate (r4) was obtained by following the same steps as in Example 1. The peeling interface when peeling off the second substrate layer was between the second substrate layer and the second alignment layer. The obtained optical laminate (r4) sequentially includes a protective film, a polarizing plate, a first bonding layer (adhesive layer (a)), a first alignment layer, a first liquid crystal layer, a second bonding layer (adhesive curing layer), a second liquid crystal layer, and a second alignment layer. The martensitic hardness H2 of the obtained optical laminate (r4) was measured, and a scratch test was performed. The results are shown in Table 1.

[0346] Table 1

[0347]

Claims

1. An optical laminate comprising, sequentially, a polarizing plate having a protective layer on one or both sides of a linear polarizing layer, a first phase retardation layer, and a second phase retardation layer. The first phase reversal layer comprises a first liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound. The second phase reversal layer comprises a second liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound. The Martens hardness H1 of the second phase difference layer at a pressurization rate of 1mN / 5s and a creep time of 5s is 10N / mm. 2 the following, The ratio of the martensitic hardness H2 to the martensitic hardness H1 at a pressure rate of 1 mN / 5 s and a creep time of 5 s on the second phase difference layer side of the optical laminate, i.e., H2 / H1, is 15 or higher. The first phase difference layer and the second phase difference layer are bonded together via a second bonding layer. The second bonding layer is an adhesive curing layer. The polarizing plate is bonded to the first phase difference layer via a first bonding layer. The first bonding layer is an adhesive curing layer.

2. An optical laminate comprising, sequentially, a polarizing plate having a protective layer on one or both sides of a linear polarizing layer, a first phase retardation layer, and a second phase retardation layer. The first phase reversal layer comprises a first liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound. The second phase reversal layer comprises a second liquid crystal layer, which is a cured layer of a polymeric liquid crystal compound. The Martens hardness H1 of the second phase difference layer at a pressurization rate of 1mN / 5s and a creep time of 5s is 10N / mm. 2 the following, The number of scratches caused by the scratch test on the second phase difference layer side of the optical laminate is less than 10 scratches per 20 mm. The first phase difference layer and the second phase difference layer are bonded together via a second bonding layer. The second bonding layer is an adhesive curing layer. The polarizing plate is bonded to the first phase difference layer via a first bonding layer. The first bonding layer is an adhesive curing layer.

3. The optical laminate according to claim 1 or 2, wherein, The adhesive curing layer constituting the second bonding layer is a curing layer of an active energy radiation-cured adhesive.

4. The optical laminate according to claim 1 or 2, wherein, The adhesive curing layer constituting the first bonding layer is a curing layer of an active energy radiation-cured adhesive.

5. The optical laminate according to claim 1 or 2, wherein, The first phase difference layer is a stack of the first liquid crystal layer and the first alignment layer.

6. The optical laminate according to claim 1 or 2, wherein, The second phase difference layer is a stack of the second liquid crystal layer and the second alignment layer. The second alignment layer is disposed on the side of the second liquid crystal layer opposite to the side of the first phase difference layer.

7. An optical laminate with an adhesive layer, comprising the optical laminate according to any one of claims 1 to 6 and a third adhesive layer, wherein the optical laminate has an adhesive layer. The third bonding layer is located on the side of the second phase difference layer opposite to the side of the first phase difference layer.

8. The optical laminate with an bonding layer according to claim 7, wherein, On the side of the third bonding layer opposite to the side of the second phase difference layer, there is a release film that can be peeled off relative to the third bonding layer.

9. A method for manufacturing an optical laminate with an adhesive layer, as described in claim 7 or 8, comprising: The process of conveying the optical laminate while the conveying roller is brought against the second phase difference layer side of the optical laminate; and The process of forming the third bonding layer on the side of the second phase difference layer of the optical laminate after the conveying process.

10. The method for manufacturing an optical laminate with an adhesive layer according to claim 9, further comprising a step of laminating a release film on the side of the third adhesive layer opposite to the side of the second phase difference layer.

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