Kit for image display panel and image display panel

Abstract

Provided is an image display panel kit suitable for manufacturing an image display panel in which a conductive structure is formed on a side surface of an optical laminate, and in which the antistatic performance is not susceptible to deterioration even when the image display panel passes through a high-temperature and humid environment. This image display panel kit is provided with: an optical laminate (10) having a polarizing film (2) and an adhesive sheet (1); and a conductive paste. The conductive paste is applied to a portion of the side surface (10c) of the optical laminate (10), the portion having a dimensional change amount of 80 [mu] m or less as determined by a test 1, and the conductive structure (20) is formed. And the elongation at break as determined by testing two pairs of conductive pastes is 5% or more.

Description

Technical Field

[0001] The present invention relates to a kit for an image display panel and an image display panel. Background Art

[0002] Various image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices have, for example, an image display unit such as a liquid crystal cell and an EL light-emitting element, and an image display panel formed by laminating an optical laminate including a polarizing film and an adhesive sheet. The adhesive sheet is mainly used for bonding between films contained in the optical laminate and for bonding between the image display unit and the optical laminate.

[0003] In the case of an image display device, static electricity is generated during its manufacture (for example, when an optical laminate is attached to an image display unit via an adhesive sheet) or during use (for example, when a user touches the image display device). If the image display device is charged due to this static electricity, problems such as poor display may occur. Patent Document 1 discloses that an antistatic agent is added to the adhesive sheet in order to prevent charging of the image display device.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-528448 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In a case where an image display device is used in an environment where static electricity is particularly likely to be generated, such as an environment where other electronic devices are present around, such as inside a vehicle, it is necessary to sufficiently suppress charging of the image display device. From the viewpoint of sufficiently suppressing charging of the image display device, a countermeasure of using an image display panel in which a conduction structure is provided on the side surface of the optical laminate can be considered. As an example, the conduction structure can be formed by applying a conductive paste to the side surface of the optical laminate and curing it as needed.

[0009] However, according to the research by the present inventors, for an image display panel having a conduction structure formed by a conductive paste, its antistatic performance tends to be significantly reduced after being exposed to a high-temperature and high-humidity environment.

[0010] Therefore, an object of the present invention is to provide a kit for an image display panel suitable for manufacturing an image display panel in which a conduction structure is formed on the side surface of an optical laminate and whose antistatic performance is not easily reduced even after being exposed to a high-temperature and high-humidity environment.

[0011] Means for Solving the Problems

[0012] The inventors of the present invention have conducted in-depth research and as a result, newly discovered that in the case of existing image display devices, fractures occur between the conduction structure and the optical laminate in a high-temperature and high-humidity environment, resulting in a significant reduction in antistatic performance, and thus the present invention has been completed.

[0013] The present invention provides a kit for an image display panel, comprising:

[0014] an optical laminate having a polarizing film and an adhesive sheet, and

[0015] a conductive paste,

[0016] The above-mentioned conductive paste is coated on a portion of the side surface of the above-mentioned optical laminate where the dimensional change amount obtained by the following Test 1 is 80 μm or less to form a conduction structure,

[0017] The elongation at break obtained by the following Test 2 for the above-mentioned conductive paste is 5% or more,

[0018] Test 1: The above-mentioned optical laminate is pasted on a non-alkali glass via the above-mentioned adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH, and the dimensional change amount of the above-mentioned optical laminate in the plane direction before and after the above-mentioned heat treatment is determined;

[0019] Test 2: A flat film with a thickness of 2 mm is made from the above-mentioned conductive paste, and a dumbbell-shaped No. 1 test piece is made by punching the above-mentioned flat film. The above-mentioned test piece is set on a tensile testing machine, and a tensile test is performed under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min, and the elongation at break (elongation at break) when the above-mentioned test piece breaks is determined.

[0020] In addition, the present invention provides an image display panel, comprising:

[0021] an image display unit,

[0022] an optical laminate having a polarizing film and an adhesive sheet, and

[0023] a conduction structure formed of a conductive paste and in contact with a portion of the side surface of the above-mentioned optical laminate where the dimensional change amount obtained by the following Test 1 is 80 μm or less,

[0024] The elongation at break obtained by the following Test 2 for the above-mentioned conductive paste is 5% or more,

[0025] Test 1: The above-mentioned optical laminate is pasted on a non-alkali glass via the above-mentioned adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH, and the dimensional change amount of the above-mentioned optical laminate in the plane direction before and after the above-mentioned heat treatment is determined;

[0026] Test 2: A flat film with a thickness of 2 mm was made from the above conductive paste, and a dumbbell-shaped No. 1 test piece was made by punching the above flat film. The above test piece was set on a tensile testing machine, and a tensile test was carried out under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min to determine the elongation at break (breaking elongation) when the above test piece broke.

[0027] Effects of the Invention

[0028] According to the present invention, it is possible to provide a kit for an image display panel suitable for manufacturing an image display panel having a conduction structure formed on a side surface of an optical laminate and having antistatic performance that is not easily reduced even after being exposed to a high-temperature and high-humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a cross-sectional view schematically showing an example of the optical laminate of the present invention.

[0030] Figure 2 It is a view for explaining the amount of dimensional change of the optical laminate during the heat treatment in Test 1.

[0031] Figure 3A It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0032] Figure 3B It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0033] Figure 3C It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0034] Figure 3D It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0035] Figure 3E It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0036] Figure 3F It is a cross-sectional view schematically showing an example of the image display panel of the present invention.

[0037] Figure 4 It is a scanning electron microscope (SEM) image of the surface of the image display panel of Example 1 after the heat treatment.

[0038] Figure 5 It is an SEM image of the surface of the image display panel of Example 2 after the heat treatment.

[0039] Figure 6It is an SEM image showing the surface of the image display panel of Comparative Example 1 after heat treatment.

[0040] Figure 7 It is an SEM image showing the surface of the image display panel of Comparative Example 2 after heat treatment. Detailed Description

[0041] The kit for an image display panel according to the first aspect of the present invention includes: an optical laminate having a polarizing film and an adhesive sheet, and a conductive paste.

[0042] The above conductive paste is applied to a portion of the side surface of the above optical laminate where the dimensional change amount obtained by the following Test 1 is 80 μm or less to form a conduction structure.

[0043] The elongation at break obtained by the following Test 2 for the above conductive paste is 5% or more.

[0044] Test 1: The above optical laminate is pasted on a non-alkali glass via the above adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH. Determine the dimensional change amount of the above optical laminate in the plane direction before and after the above heat treatment.

[0045] Test 2: A flat film with a thickness of 2 mm is made from the above conductive paste. The above flat film is blanked to produce a dumbbell-shaped No. 1 test piece. The above test piece is set on a tensile testing machine, and a tensile test is performed under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min to determine the elongation at break (elongation at break) when the above test piece breaks.

[0046] In the second aspect of the present invention, for example, in the kit of the first aspect, the above elongation at break is 25% or more.

[0047] In the third aspect of the present invention, for example, in the kit of the first or second aspect, the above conductive paste contains a metal and an adhesive.

[0048] In the fourth aspect of the present invention, for example, in the kit of the third aspect, the above adhesive contains at least one selected from a polyester resin and a silicone resin.

[0049] In the fifth aspect of the present invention, for example, in the kit of the third or fourth aspect, the above adhesive substantially does not contain an epoxy resin.

[0050] In the sixth aspect of the present invention, for example, in the kit of any one of the third to fifth aspects, the above metal contains silver.

[0051] In the seventh aspect of the present invention, for example, in the kit of any one of the first to sixth aspects, the polarizing film has two protective films and a polarizer disposed between the two protective films.

[0052] In the eighth aspect of the present invention, for example, in the kit of the seventh aspect, the thickness of the polarizer is 6 μm or more.

[0053] In the ninth aspect of the present invention, for example, in the kit of any one of the first to eighth aspects, the adhesive sheet is formed of an adhesive composition containing a (meth)acrylic polymer (A).

[0054] In the tenth aspect of the present invention, for example, in the kit of the ninth aspect, the (meth)acrylic polymer (A) has a structural unit derived from an ether group-containing monomer.

[0055] In the eleventh aspect of the present invention, for example, in the kit of the ninth or tenth aspect, the adhesive composition further contains an antistatic agent.

[0056] In the twelfth aspect of the present invention, for example, in the kit of any one of the first to eleventh aspects, the storage modulus G' of the adhesive sheet at 25°C is 9.0×10 4 Pa or more.

[0057] In the thirteenth aspect of the present invention, for example, in the kit of any one of the first to twelfth aspects, the adhesive sheet is directly joined to the polarizing film.

[0058] The image display panel according to the fourteenth aspect of the present invention includes:

[0059] An image display unit,

[0060] An optical laminate including a polarizing film and an adhesive sheet, and

[0061] A conduction structure formed of a conductive paste and in contact with a portion of the side surface of the optical laminate having a dimensional change amount of 80 μm or less obtained by the following Test 1,

[0062] The elongation at break of the conductive paste obtained by the following Test 2 is 5% or more.

[0063] Test 1: The optical laminate is pasted on a non-alkali glass via the adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH. Determine the dimensional change amount of the optical laminate in the plane direction before and after the heat treatment.

[0064] Test 2: A flat film with a thickness of 2 mm was made from the above conductive paste. A dumbbell-shaped No. 1 test piece was made by punching the above flat film. The above test piece was set on a tensile testing machine, and a tensile test was carried out under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min to determine the elongation at break (elongation at break) when the above test piece broke.

[0065] In the 15th aspect of the present invention, for example, a touch sensing function is built in the image display panel of the 14th aspect.

[0066] Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0067] <Embodiments of the Kit for Image Display Panel>

[0068] The kit for an image display panel of the present embodiment includes an optical laminate and a conductive paste. An example of the optical laminate that the kit for an image display panel of the present embodiment may include is shown in Figure 1 . Figure 1 The optical laminate 10 has a polarizing film 2 and an adhesive sheet 1 and is composed of, for example, only the adhesive sheet 1 and the polarizing film 2. In the optical laminate 10, it is preferable that the adhesive sheet 1 is directly joined to the polarizing film 2. However, the optical laminate 10 may also include other members (for example, an anchoring layer, a conductive layer) in addition to the adhesive sheet 1 and the polarizing film 2, and the other members may be disposed between the adhesive sheet 1 and the polarizing film 2. The optical laminate 10 can be attached to an object (for example, an image display unit) via the adhesive sheet 1 and thus can be used in the form of a polarizing film with an adhesive sheet.

[0069] In the present embodiment, the optical laminate 10 is, for example, in a sheet shape and has a pair of main surfaces 10a and 10b and a side surface 10c that face each other. The conductive paste is applied to a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by the following Test 1 is 80 μm or less to form a conduction structure. It should be noted that when forming the conduction structure, the conductive paste applied to the above portion may be cured as needed.

[0070] Test 1: The optical laminate 10 was pasted on a non-alkali glass via the adhesive sheet 1, and a heat treatment was carried out for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH. The dimensional change amount of the optical laminate 10 in the plane direction before and after the heat treatment was determined.

[0071] Specifically, Test 1 was carried out by the following method. First, the optical laminate 10 was prepared. The optical laminate 10 is, for example, rectangular in plan view and has dimensions of 50 to 1500 mm in length and 50 to 1500 mm in width. Figure 2This is an example of a plan view concept diagram near the end of the optical laminate 10. Before Figure 2 In this, the outer edge of the optical laminate 10 before the heat treatment is shown by a solid line. As Figure 2 shown, the optical laminate 10 has, for example, a rectangular shape with chamfered corners when viewed from above. The side surface 10c of the optical laminate 10 has, for example, a portion S1 extending along the absorption axis direction of the polarizing film 2, a portion S2 extending along the slow axis direction of the polarizing film 2, and a portion S3 defining the chamfered corner. It should be noted that the absorption axis direction and the slow axis direction of the polarizing film 2 are usually orthogonal to each other.

[0072] Next, the optical laminate 10 is adhered to the non-alkali glass via the adhesive sheet 1. The non-alkali glass is a glass that substantially does not contain an alkali component (alkali metal oxide). Specifically, the weight ratio of the alkali component in the glass is, for example, 1000 ppm or less, and further 500 ppm or less. The non-alkali glass is, for example, plate-shaped and has a thickness of 0.5 mm or more. The adhesion of the optical laminate 10 to the non-alkali glass is performed, for example, by overlapping the entire surface of the optical laminate 10 with the non-alkali glass and pressing them by reciprocating a 2 kg roller once.

[0073] Next, the heat treatment is performed by disposing the optical laminate 10 in an environment of a temperature of 85°C and a humidity of 85% RH for 240 hours. At this time, the optical laminate 10 usually shrinks in the plane direction. In Figure 2 this, the outer edge of the optical laminate 10 after the heat treatment is shown by a dashed line. In Figure 2 this, L1 corresponds to the dimensional change amount (shrinkage amount) of the portion S1 in the plane direction before and after the heat treatment, L2 corresponds to the dimensional change amount (shrinkage amount) of the portion S2 in the plane direction before and after the heat treatment, and L3 corresponds to the dimensional change amount (shrinkage amount) of the portion S3 in the plane direction before and after the heat treatment. The dimensional change amounts L1 to L3 can be determined by microscopic observation.

[0074] It should be noted that the shrinkage of the optical laminate 10 generally has a tendency to occur more strongly in the absorption axis direction of the polarizing film 2 than in the slow axis direction of the polarizing film 2. Therefore, the dimensional change amount L1 (μm) of the portion S1, the dimensional change amount L2 (μm) of the portion S2, and the dimensional change amount L3 (μm) of the portion S3 satisfy, for example, the relationship L2 > L3 > L1.

[0075] In the present embodiment, preferably, the dimensional change amount L1 of the portion S1 is 80 μm or less, and the conductive paste is applied to the portion S1 to form a conduction structure. In this case, the conductive paste may be applied to the entire portion S1 or may be applied to a part of the portion S1. When the dimensional change amount L1 is 80 μm or less, the dimensional change amount L2 of the portion S2 and the dimensional change amount L3 of the portion S3 may be greater than 80 μm respectively, or may be 80 μm or less. When the dimensional change amounts L1 to L3 are all 80 μm or less, the conductive paste may be applied to at least one of the portions S1 to S3 to form a conduction structure.

[0076] The dimensional change amounts L1 to L3 (especially the dimensional change amount L1) may be 70 μm or less, may be 60 μm or less, 50 μm or less, 40 μm or less, and may further be 35 μm or less. The lower limit of the dimensional change amounts L1 to L3 is not particularly limited. For example, it is 10 μm or more, may be 20 μm or more, and may further be 30 μm or more.

[0077] It should be noted that the ratio L1 / L2 of the dimensional change amount L1 (μm) to the dimensional change amount L2 (μm) is not particularly limited. For example, it is less than 0.8, may be 0.7 or less, and may further be 0.6 or less. When the ratio L1 / L2 is less than 0.8, the conduction structure formed by applying the conductive paste to the portion S1 easily maintains the adhesion to the portion S1. The lower limit of the ratio L1 / L2 is not particularly limited. For example, it is 0.4.

[0078] In addition, in the present embodiment, the elongation at break obtained for the conductive paste by the following Test 2 is 5% or more.

[0079] Test 2: A flat film with a thickness of 2 mm is made from the conductive paste. The flat film is blanked to make a dumbbell-shaped No. 1 test piece. The test piece is set on a tensile testing machine, and a tensile test is carried out under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min to determine the elongation at break (elongation at break) when the test piece breaks.

[0080] In Test 2, the method for making the flat film is not particularly limited. As an example, the flat film can be made by applying the conductive paste to a substrate and curing it. The conductive paste can be cured, for example, by heat treatment in an environment of 60°C to 150°C for 15 minutes to 5 hours.

[0081] In Test 2, the shape of the test piece (dumbbell-shaped No. 1) is specified by JIS K6251:2017, for example. As the tensile testing machine, for example, the tensile testing machine "Autograph AG-10G" manufactured by Shimadzu Corporation can be used. The tensile test is carried out by stretching the test piece in the length direction of the test piece.

[0082] The elongation at break obtained by Test 2 is preferably 10% or more, more preferably 15% or more, 20% or more, 25% or more, and further preferably 30% or more. The upper limit of the elongation at break is not particularly limited, for example, it is 100% or less.

[0083] As described above, in the kit of the present embodiment, the conductive paste is applied to a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by Test 1 is 80 μm or less to form a conduction structure. In addition, the elongation at break of the conductive paste obtained by Test 2 is 5% or more. The image display device and the image display panel produced from the kit that satisfies these requirements are less likely to break between the conduction structure and the optical laminate even after being exposed to a high-temperature and high-humidity environment. Therefore, there is a tendency that the antistatic performance is not easily reduced.

[0084] [Adhesive sheet]

[0085] In the present embodiment, the adhesive sheet 1 is a layer containing an adhesive. Examples of the adhesive contained in the adhesive sheet 1 are rubber-based adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinylpyrrolidone adhesives, polyacrylamide adhesives, and cellulose adhesives. From the viewpoints of excellent optical transparency, having appropriate wettability, cohesiveness, adhesiveness, etc., and also excellent weather resistance, heat resistance, etc., the adhesive can be an acrylic adhesive. In other words, the adhesive sheet 1 can be an acrylic adhesive sheet. Hereinafter, the adhesive sheet 1 as an acrylic adhesive sheet will be described.

[0086] In the present embodiment, the adhesive sheet 1 is formed from an adhesive composition. The adhesive composition contains, for example, a (meth)acrylic polymer (A), and may further contain an antistatic agent. The content of the (meth)acrylic polymer (A) in the adhesive composition can be 50% by weight or more, 60% by weight or more, 70% by weight or more, and further 80% by weight or more. In the present specification, (meth)acrylic acid means acrylic acid and methacrylic acid. (Meth)acrylate means acrylate and methacrylate. It should be noted that the adhesive composition can be a photocurable composition containing a monomer group containing a (meth)acrylic monomer and / or a partial polymer of the monomer group. As the (meth)acrylic monomer, the (meth)acrylic monomers described later for the (meth)acrylic polymer (A) can be mentioned.

[0087] [(Meth)acrylic polymer (A)]

[0088] (Meth)acrylic polymer (A) may, for example, have a structural unit derived from an alkyl (meth)acrylate and may have such a structural unit as a main component. The number of carbon atoms of the alkyl group contained in the alkyl (meth)acrylate used to form the main skeleton of the (meth)acrylic polymer (A) is not particularly limited and is, for example, 1 to 18. The alkyl group may be linear, branched, or cyclic. Examples of the alkyl group include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isotetradecyl, undecyl, tridecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. The alkyl (meth)acrylates may be used alone or in combination, and the average number of carbon atoms of the alkyl group is preferably 3 to 9.

[0089] From the viewpoint of improving the adhesiveness of the adhesive sheet, in the (meth)acrylic polymer (A), the content ratio of the structural unit derived from the alkyl (meth)acrylate is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and further preferably 80% by weight or more. However, depending on the situation, the content ratio of the structural unit in the (meth)acrylic polymer (A) may also be less than 50% by weight, may be 30% by weight or less, and further may be 10% by weight or less.

[0090] As monomers constituting the (meth)acrylic polymer (A), in addition to the alkyl (meth)acrylates, comonomers such as an ether group-containing monomer, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, and an aromatic ring-containing monomer can also be cited. The comonomers may be used alone or in combination.

[0091] (Meth)acrylic polymer (A) preferably contains a structural unit derived from an ether group-containing monomer. The ether group-containing monomer is a compound that contains an ether group in its structure and contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group.

[0092] The ether group-containing monomer preferably contains an alkoxy group-containing monomer. The alkoxy group-containing monomer is, for example, an alkylene oxide adduct represented by the following formula (1). R in formula (1) 1 is a hydrogen atom or a methyl group. R in formula (1) 2 is an alkyl group. The alkyl group may be linear or may have a branch. R 2 is preferably a linear alkyl group. Examples of R 2 are methyl and ethyl. n in formula (1) is an integer of 1 to 30, preferably an integer of 1 to 12, and may be an integer of 1 to 5.

[0093] [Chemical formula 1]

[0094]

[0095] Examples of the alkylene oxide adduct represented by the formula (1) are 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate. The alkoxy group-containing monomer preferably contains 2-methoxyethyl acrylate (MEA).

[0096] The ether group-containing monomer is not limited to the above-mentioned alkylene oxide adduct. The ether group-containing monomer may have a ring structure, and the ring structure may have an ether group. The ring structure may also contain functional groups other than the ether group. Examples of the ring structure having an ether group include a tetrahydrofuran ring and a dioxane ring. Examples of the ether group-containing monomer having a ring structure are cyclic trimethylolpropane formal (meth)acrylate and tetrahydrofurfuryl (meth)acrylate.

[0097] In the (meth)acrylic polymer (A), the content of the structural unit derived from the ether group-containing monomer is not particularly limited. For example, it is 25% by weight or more, preferably 30% by weight or more, and may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, and further may be 90% by weight or more. The upper limit of the content is, for example, 99% by weight or less, and depending on the situation, it may be 80% by weight or less, or may be 70% by weight or less.

[0098] The carboxyl group-containing monomer is a compound that contains a carboxyl group in its structure and contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Among these, acrylic acid is preferred from the viewpoints of copolymerizability, price, and improvement of the adhesive properties of the adhesive sheet 1.

[0099] In the (meth)acrylic polymer (A), the structural unit derived from the carboxyl group-containing monomer has high reactivity with the crosslinking agent, which contributes to the improvement of the cohesiveness and heat resistance of the adhesive sheet 1. The structural unit derived from the carboxyl group-containing monomer is also suitable for making the adhesive sheet 1 have both durability and reworkability. In the (meth)acrylic polymer (A), the content of the structural unit derived from the carboxyl group-containing monomer is not particularly limited. For example, it is 10% by weight or less, preferably 0.01 to 8% by weight, 0.05 to 6% by weight, and more preferably 0.1 to 5% by weight. When the content of the structural unit derived from the carboxyl group-containing monomer is 0.01% by weight or more, there is a tendency for the durability of the adhesive sheet 1 to be improved. When the content is 10% by weight or less, there is a tendency for the reworkability of the adhesive sheet 1 to be improved.

[0100] ​A hydroxyl group-containing monomer is a compound that contains a hydroxyl group in its structure and contains a polymerizable unsaturated double bond such as (meth)acryloyl group or vinyl group. Examples of the hydroxyl group-containing monomer include: hydroxyl group-containing (meth)acrylic acid alkyl esters such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxydodecyl (meth)acrylate; and hydroxyl group-containing (meth)acrylic acid cycloalkyl esters such as methyl (4-hydroxymethylcyclohexyl)acrylate. Among these, from the viewpoint of durability, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred.

[0101] Similar to the carboxyl group-containing monomer, the structural unit derived from the hydroxyl group-containing monomer has a high reactivity with the crosslinking agent, which contributes to the improvement of the cohesiveness and heat resistance of the adhesive sheet 1. The structural unit derived from the hydroxyl group-containing monomer is also suitable for improving the reworkability of the adhesive sheet 1. In the (meth)acrylic polymer (A), the content of the structural unit derived from the hydroxyl group-containing monomer is not particularly limited, for example, it is 3% by weight or less, preferably 0.01 to 3% by weight, 0.1 to 2% by weight, and more preferably 0.2 to 2% by weight. When the content of the structural unit derived from the hydroxyl group-containing monomer is 0.01% by weight or more, there is a tendency that the reactivity with the crosslinking agent is improved, and the durability and adhesive properties of the adhesive sheet 1 are also improved. In addition, from the viewpoint of the durability of the adhesive sheet 1, the content of the structural unit derived from the hydroxyl group-containing monomer is preferably 3% by weight or less.

[0102] An amide group-containing monomer is a compound that contains an amide group in its structure and contains a polymerizable unsaturated double bond such as (meth)acryloyl group or vinyl group. Examples of the amide group-containing monomer include: acrylamide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propyl(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, mercaptoethyl(meth)acrylamide; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine; and N-vinyl-containing lactam monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam. Among these, from the viewpoint of suppressing the increase in surface resistance value of the adhesive sheet 1 with time in a multi-humid environment, etc., N-vinyl-containing lactam monomers are preferred.

[0103] In the (meth)acrylic polymer (A), from the viewpoint of the anchoring force between the polarizing film 2 and the adhesive sheet 1, the content ratio of the structural unit derived from the amide group-containing monomer is preferably 10% by weight or less, more preferably 5% by weight or less. From the viewpoint of suppressing the increase over time of the surface resistance value of the adhesive sheet 1 in a multi-humid environment, the content ratio of the structural unit derived from the amide group-containing monomer is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and further preferably 0.5% by weight or more.

[0104] The structural unit derived from the amide group-containing monomer is suitable for improving the compatibility of the (meth)acrylic polymer (A) with the antistatic agent (especially an ionic compound). By improving their compatibility, there is a tendency to suppress the increase over time of the surface resistance value of the adhesive sheet 1 in a multi-humid environment. The structural unit derived from the amide group-containing monomer also has a tendency to improve the durability of the adhesive sheet 1 against glass and the transparent conductive layer (e.g., ITO layer). According to this adhesive sheet 1, it is easy to suppress the peeling and warping of the optical laminate 10 from the image display unit. In addition, the structural unit derived from the amide group-containing monomer has a tendency to contribute to improving the durability of the adhesive sheet 1 in a multi-humid environment.

[0105] The aromatic ring-containing monomer is a compound that contains an aromatic ring structure in its structure and contains polymerizable unsaturated double bonds such as (meth)acryloyl group and vinyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring, and a biphenyl ring. The aromatic ring-containing monomer is preferably an aromatic ring-containing (meth)acrylate.

[0106] Examples of the aromatic ring-containing (meth)acrylate include: benzyl (meth)acrylate, phenyl (meth)acrylate, o-phenylphenol (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, ethylene oxide-modified cresol (meth)acrylate, phenol ethylene oxide-modified (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, methoxybenzyl (meth)acrylate, chlorobenzyl (meth)acrylate, tolyl (meth)acrylate, styryl (meth)acrylate and other (meth)acrylates having a benzene ring; hydroxyethylated β-naphthol acrylate, 2-naphthyl ethyl (meth)acrylate, 2-naphthoxyethyl acrylate, 2-(4-methoxy-1-naphthoxy)ethyl (meth)acrylate and other (meth)acrylates having a naphthalene ring; biphenyl (meth)acrylate and other aromatic ring-containing (meth)acrylates having a biphenyl ring. Among these, from the viewpoint of improving the adhesion characteristics and durability of the adhesive sheet 1, benzyl (meth)acrylate and phenoxyethyl (meth)acrylate are preferred.

[0107] In the (meth)acrylic polymer (A), the content of the structural unit derived from the aromatic ring-containing monomer is not particularly limited, for example, it is 25% by weight or less, preferably 3 to 25% by weight, 10 to 22% by weight, and more preferably 14 to 20% by weight. When the content of the structural unit derived from the aromatic ring-containing monomer is 3% by weight or more, there is a tendency to suppress uneven display of the image display device. When the content is 25% by weight or less, there is a tendency to improve the durability of the adhesive sheet 1.

[0108] As the monomer constituting the (meth)acrylic polymer (A), in addition to the (meth)acrylic acid alkyl ester and the above-mentioned comonomer, other comonomers having a polymerizable functional group containing an unsaturated double bond such as (meth)acryloyl or vinyl may be used for the purpose of improving the adhesiveness and heat resistance of the adhesive sheet 1. The other comonomers may be used alone or in combination.

[0109] As other comonomers, for example, the following can be cited: monomers containing an acid anhydride group such as maleic anhydride and itaconic anhydride; a caprolactone adduct of acrylic acid; monomers containing a sulfonic acid group such as allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, and (meth)acrylic acid sulfopropyl ester; monomers containing a phosphate group such as 2-hydroxyethyl acryloyl phosphate; (meth)acrylic acid alkylaminoalkyl esters such as (meth)acrylic acid aminoethyl ester, (meth)acrylic acid N,N-dimethylaminoethyl ester, and (meth)acrylic acid tert-butylaminoethyl ester; (meth)acrylic acid alkoxyalkyl esters such as (meth)acrylic acid methoxyethyl ester and (meth)acrylic acid ethoxyethyl ester; succinimide monomers such as N-(meth)acryloxymethylene succinimide, N-(meth)acryloyl-6-oxohexamethylene succinimide, and N-(meth)acryloyl-8-oxooctamethylene succinimide; maleimide monomers such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-dodecyl maleimide, and N-phenyl maleimide; itaconimide monomers such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-dodecyl itaconimide; vinyl monomers such as vinyl acetate and vinyl propionate; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; (meth)acrylic acid glycidyl ester and other (meth)acrylic acid esters containing an epoxy group; diol (meth)acrylic esters such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; (meth)acrylic acid tetrahydrofurfuryl ester, fluorine-containing (meth)acrylic ester, polysiloxane (meth)acrylate, and (meth)acrylic acid 2-methoxyethyl ester and other (meth)acrylic acid ester monomers; vinyl-containing monomers such as isoprene, butadiene, isobutene, and vinyl ether; silane monomers containing a silicon atom such as 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, and 10-acryloyloxydecyltriethoxysilane, etc.

[0110] In addition, as other comonomers, for example, the following can be cited: dipropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate and other polyfunctional monomers having two or more unsaturated double bonds.

[0111] In the case of using other comonomers, in the (meth)acrylic polymer (A), the content of the structural unit derived from the other comonomer is preferably 10% by weight or less, more preferably 7% by weight or less, and still more preferably 5% by weight or less.

[0112] The weight-average molecular weight of the (meth)acrylic polymer (A) is generally 300,000 to 4,000,000. From the viewpoint of durability, the weight-average molecular weight of the (meth)acrylic polymer (A) is preferably 1,000,000 or more, and may be 1,500,000 or more. The weight-average molecular weight of the (meth)acrylic polymer (A) can be 3,000,000 or less, and can also be 2,000,000 or less. From the aspect of heat resistance, a weight-average molecular weight of 300,000 or more is preferred. When the weight-average molecular weight is 4,000,000 or less, the adhesive sheet tends not to harden easily and not to peel off easily. The weight-average molecular weight (Mw) / number-average molecular weight (Mn) representing the molecular weight distribution is preferably 1.8 to 10, more preferably 1.8 to 7, and still more preferably 1.8 to 5. From the aspect of durability, a molecular weight distribution (Mw / Mn) of 10 or less is preferred. The weight-average molecular weight and the molecular weight distribution (Mw / Mn) are determined by measurement by GPC (gel permeation chromatography) and calculated by conversion to polystyrene.

[0113] The (meth)acrylic polymer (A) can be produced by known polymerization methods such as solution polymerization, radiation polymerization such as electron beam and UV, bulk polymerization, emulsion polymerization and other various radical polymerizations. The obtained (meth)acrylic polymer (A) can be any copolymer such as a random copolymer, a block copolymer, a graft copolymer and the like.

[0114] In solution polymerization, as the polymerization solvent, for example, ethyl acetate, toluene and the like can be used. Solution polymerization is carried out, for example, by adding a polymerization initiator under a stream of an inert gas such as nitrogen and usually at about 50 to 70 °C under reaction conditions of about 5 to 30 hours.

[0115] There are no particular limitations on the polymerization initiator, chain transfer agent, emulsifier, etc. used for free radical polymerization, and they can be appropriately selected and used. The weight average molecular weight of the (meth)acrylic acid polymer (A) can be controlled according to the amounts of the polymerization initiator and chain transfer agent, reaction conditions, etc. Therefore, the amounts of the polymerization initiator and chain transfer agent can be appropriately adjusted according to their compositions.

[0116] Examples of the polymerization initiator include azo initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethylisobutyramidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (for example, VA-057 manufactured by Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate; peroxides such as di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneopentanoate, tert-butyl peroxyneopentanoate, dilauroyl peroxide, dioctanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, bis(4-methylbenzoyl) peroxide, benzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-bis(tert-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, and hydrogen peroxide; redox initiators combining peroxides and reducing agents such as a combination of persulfate and sodium bisulfite and a combination of peroxide and sodium ascorbate. However, the polymerization initiator is not limited to the above examples.

[0117] The polymerization initiator can be used alone or two or more thereof can be used in combination. The total amount of the polymerization initiator is, for example, 0.005 to 1 part by weight, or can be 0.02 to 0.5 part by weight, relative to 100 parts by weight of the monomer component.

[0118] Examples of the chain transfer agent include dodecyl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent can be used alone or two or more thereof can be used in combination. The total amount of the chain transfer agent is, for example, 0.1 part by weight or less relative to 100 parts by weight of the monomer component.

[0119] In radiation polymerization, polymerization is carried out by irradiating a monomer group with radiation such as an electron beam or UV to form a (meth)acrylic polymer (A). In the case of forming an adhesive sheet from a photocurable composition, polymerization is carried out by irradiating the photocurable composition with light to form a (meth)acrylic polymer (A). In the case of radiation polymerization using an electron beam, the use of a photoinitiator is not particularly necessary. In the case of radiation polymerization using UV, a photoinitiator can be used due to advantages such as being able to shorten the polymerization time. The photoinitiator can be used alone or two or more kinds can be used in combination.

[0120] Examples of photoinitiators are various photoinitiators such as benzoin ethers, acetophenones, α-hydroxy ketones, photoactive oximes, benzoins, benzils, benzophenones, ketals, thioxanthones, etc. However, the photoinitiator is not limited to the above examples. The amount of the photoinitiator is, for example, 0.05 to 1.5 parts by weight, and can also be 0.1 to 1 part by weight relative to 100 parts by weight of the monomer component.

[0121] (Antistatic agent)

[0122] An antistatic agent is a material that can impart antistatic properties to the adhesive sheet 1. Examples of antistatic agents include ionic surfactants, conductive polymers, conductive fine particles, ionic compounds, etc.

[0123] Examples of ionic surfactants include cationic surfactants such as quaternary ammonium salt type, salt type, sulfonium salt type, etc.; anionic surfactants such as carboxylic acid type, sulfonate type, sulfate type, phosphate type, phosphite type, etc.; zwitterionic surfactants such as sulfobetaine type, alkyl betaine type, alkyl imidazole betaine type, etc.; nonionic surfactants such as polyol derivatives, β-cyclodextrin inclusion compounds, sorbitan fatty acid monoesters, sorbitan fatty acid diesters, polyoxyalkylene derivatives, amine oxides, etc.

[0124] Examples of conductive polymers include polymers such as polyanilines, polythiophenes, polypyrroles, polyquinoxalines, etc. Among them, polyaniline, polythiophene, etc. that are easily functional as water-soluble conductive polymers or water-dispersible conductive polymers are preferred, and polythiophene is particularly preferred.

[0125] As the conductive fine particles, for example, metal oxide fine particles such as tin oxide-based, antimony oxide-based, indium oxide-based, zinc oxide-based, etc. are exemplified, and tin oxide-based fine particles are preferred. As the material of the tin oxide-based fine particles, for example, tin oxide, antimony-doped tin oxide, indium-doped tin oxide, aluminum-doped tin oxide, tungsten-doped tin oxide, a composite of titanium oxide - cerium oxide - tin oxide, a composite of titanium oxide - tin oxide, etc. are exemplified. The average particle diameter of the conductive fine particles is, for example, 1 to 100 nm, preferably 2 to 50 nm. The average particle diameter of the conductive fine particles means the particle diameter (d50) corresponding to 50% of the volume accumulation in the particle size distribution measured by, for example, a laser diffraction particle size analyzer, etc.

[0126] The antistatic agent preferably contains an ionic compound. From the aspect of the antistatic function, the ionic compound is preferably an ionic liquid.

[0127] As the ionic compound, for example, alkali metal salts and / or organic cation - anion salts are exemplified. As the alkali metal salts, for example, organic salts and inorganic salts of alkali metals are exemplified. From the viewpoint of compatibility in the adhesive sheet 1, the alkali metal salts are preferably organic salts of alkali metals. In the present specification, the organic cation - anion salt means an organic salt containing an organic cation. The anion contained in the organic cation - anion salt may be an organic anion or an inorganic anion. From the viewpoint of compatibility in the adhesive sheet 1, the anion contained in the organic cation - anion salt is preferably an organic anion. Sometimes the organic cation - anion salt is referred to as an ionic liquid or an ionic solid.

[0128] As the alkali metal ions contained in the alkali metal salts, for example, lithium ions, sodium ions, and potassium ions are exemplified, and lithium ions are preferred.

[0129] As the anions contained in the organic salts of alkali metals, for example, CH3COO - 、CF3COO - 、CH3SO3 - 、CF3SO3 - 、(CF3SO2)3C - 、C4F9SO3 - 、C3F7COO - 、(CF3SO2)(CF3CO)N - 、 - O3S(CF2)3SO3 - 、(CN)2N - and the anions represented by the following general formulas (a) to (d).

[0130] (a)(C n F 2n+1 SO2)2N - (wherein n is an integer of 1 to 10)

[0131] (b) CF2(C m F 2m SO2)2N - (where m is an integer from 1 to 10)

[0132] (c) - O3S(CF2) l SO3 - (where l is an integer from 1 to 10)

[0133] (d) (C p F 2p+1 SO2)N - (C q F 2q+1 SO2) (where p and q are independently integers from 1 to 10)

[0134] The anion contained in the organic salt of an alkali metal preferably contains a fluorine atom. Based on the anion containing a fluorine atom, the organic salt of an alkali metal functions as an ionic compound with excellent ionic dissociation properties.

[0135] Examples of the anion contained in the inorganic salt of an alkali metal include: Cl - 、Br - 、I - 、AlCl4 - 、Al2Cl7 - 、BF4 - 、PF6 - 、ClO4 - 、NO3 - 、AsF6 - 、SbF6 - 、NbF6 - 、TaF6 - 、(FSO2)2N - 、CO3 2- and so on.

[0136] The anion contained in the alkali metal salt is preferably (CF3SO2)2N - 、(C2F5SO2)2N - and other (perfluoroalkylsulfonyl)imides represented by the above general formula (a), and particularly preferably (CF3SO2)2N - represented by (trifluoromethanesulfonyl)imide.

[0137] As organic salts of an alkali metal, examples thereof include sodium acetate, sodium alginate, sodium lignosulfonate, sodium toluenesulfonate, LiCF3SO3, Li(CF3SO2)2N, Li(C2F5SO2)2N, Li(C4F9SO2)2N, Li(CF3SO2)3C, KO3S(CF2)3SO3K, LiO3S(CF2)3SO3K, etc. Preferred are LiCF3SO3, Li(CF3SO2)2N, Li(C2F5SO2)2N, Li(C4F9SO2)2N, Li(CF3SO2)3C, and more preferred are Li(CF3SO2)2N, Li(C2F5SO2)2N, Li(C4F9SO2)2N. The organic salts of an alkali metal are preferably lithium fluoroimide salts, and particularly preferably lithium (perfluoroalkylsulfonyl)imide salts.

[0138] As inorganic salts of an alkali metal, examples thereof include lithium perchlorate and lithium iodide.

[0139] As the organic cations contained in the organic cation-anion salts, examples thereof include: pyridine cations, piperidine cations, pyrrolidine cations, cations having a pyrroline skeleton, cations having a pyrrole skeleton, imidazole cations, tetrahydropyrimidine cations, dihydropyrimidine cations, pyrazole cations, pyrazoline cations, tetraalkylammonium cations, trialkylsulfonium cations, tetraalkyl cations, etc.

[0140] As the anions contained in the organic cation-anion salts, examples thereof include: Cl - , Br - , I - , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 - , CF3SO3 - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , (CN)2N -, C4F9SO3 - , C3F7COO - , (CF3SO2)(CF3CO)N - , (FSO2)2N - , - O3S(CF2)3SO3 - , (FSO2)2N - and the anions represented by the above general formulas (a) to (d). The anion contained in the organic cation-anion salt preferably contains a fluorine atom. According to the anion containing a fluorine atom, the organic cation-anion salt functions as an ionic compound with excellent ionic dissociation properties.

[0141] As the ionic compound, it is not limited to the above-mentioned alkali metal salts and organic cation-anion salts, and examples thereof also include inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, and ammonium sulfate. The ionic compounds can be used alone or in combination.

[0142] In the ionic compound, from the viewpoint of suppressing conduction failure in a high-temperature environment, the molecular weight of the cation is, for example, 210 or less, preferably 150 or less, 110 or less, 50 or less, and more preferably 10 or less. The smaller the molecular weight of the cation, the less likely the adhesive sheet 1 is to become soft, and there is a tendency to suppress conduction failure in a high-temperature environment. When the molecular weight of the cation is small, there is also a tendency for the surface resistance value of the adhesive sheet 1 to be easily reduced and electrostatic unevenness to be suppressed.

[0143] It should be noted that the molecular weights of lithium, sodium, and potassium are all 210 or less. Therefore, alkali metal salts containing these alkali metal ions as cations can be suitably used. In particular, as the alkali metal ion, lithium ion with the smallest molecular weight is preferred. The ionic compound is preferably a lithium salt, and particularly preferably an organic salt of lithium. When using an organic cation-anion salt, among the above cations, a cation with a molecular weight of 210 or less is preferably used.

[0144] As the antistatic agent, it is not limited to the above materials, and examples thereof also include: carbon materials such as acetylene black, Ketjen black, natural graphite, and artificial graphite; titanium black; homopolymers of monomers having an ion-conductive group such as cationic type of quaternary ammonium salts, zwitterionic type of betaine compounds, anionic type of sulfonates, or non-ionic type of glycerol, or copolymers of the monomer and other monomers; polymers having ionic conductivity such as polymers having a structural unit derived from an acrylate or methacrylate having a quaternary ammonium group; antistatic agents (permanent antistatic agents) obtained by alloying a hydrophilic polymer such as a polyethylene methacrylate copolymer with an acrylic resin.

[0145] In the adhesive composition, the compounding amount of the antistatic agent can be appropriately adjusted according to the surface resistance value of the target adhesive sheet 1, and is, for example, 0.05 to 20 parts by weight relative to 100 parts by weight of the (meth)acrylic polymer (A). From the viewpoint of improving the antistatic performance of the adhesive sheet 1, the compounding amount of the antistatic agent is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and further preferably 0.5 parts by weight or more relative to 100 parts by weight of the (meth)acrylic polymer (A). From the viewpoint of the durability of the adhesive sheet 1, the compounding amount of the antistatic agent is preferably 20 parts by weight or less, and further preferably 10 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0146] (Crosslinking agent)

[0147] The adhesive composition may further contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent, a polyfunctional metal chelate, etc. can be used. As the organic crosslinking agent, for example, isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, imine crosslinking agents, etc. can be cited. A polyfunctional metal chelate is a chelate in which a polyvalent metal atom forms a covalent bond or a coordination bond with an organic compound. As the polyvalent metal atom, Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, etc. can be cited. The organic compound forming a covalent bond or a coordination bond contains, for example, an oxygen atom, and alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, ketone compounds, etc. can be preferably cited. The crosslinking agent can be used alone or in combination.

[0148] As the crosslinking agent, an isocyanate crosslinking agent and / or a peroxide crosslinking agent is preferred.

[0149] As the isocyanate crosslinking agent, a compound having at least two isocyanate groups (isocyanate compound) can be used. The number of isocyanate groups contained in the isocyanate compound is preferably 3 or more. The upper limit of the number of isocyanate groups is not particularly limited, and is, for example, 5. Examples of the isocyanate compound are aromatic isocyanate compounds, alicyclic isocyanate compounds, and aliphatic isocyanate compounds. The isocyanate crosslinking agent is preferably a compound capable of self-polymerization by reaction with water.

[0150] Examples of the aromatic isocyanate compound are phthalic diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

[0151] Examples of alicyclic isocyanate compounds are 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0152] Examples of aliphatic isocyanate compounds are trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0153] The isocyanate crosslinking agent can be a polymer (dimer, trimer, pentamer, etc.) of the above isocyanate compounds, an adduct obtained by addition with a polyol such as trimethylolpropane, a urea-modified product, a biuret-modified product, a urethane-modified product, an isocyanurate-modified product, a carbodiimide-modified product, or a urethane prepolymer obtained by addition with a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, etc.

[0154] The isocyanate crosslinking agent is preferably an aromatic isocyanate compound and its derivative, more preferably tolylene diisocyanate and its derivative, that is, a tolylene diisocyanate (TDI) type crosslinking agent. From the viewpoint of reactivity, the TDI type crosslinking agent is more suitable than xylylene diisocyanate and its derivative, that is, a xylylene diisocyanate (XDI) type crosslinking agent. The isocyanate crosslinking agent can contain an adduct of a polyol and tolylene diisocyanate as the TDI type crosslinking agent. Specific examples of the adduct are trimethylolpropane / toluene diisocyanate trimer adduct.

[0155] Isocyanate crosslinking agents can be commercially available products. Examples of commercially available products are Millionate MT, Millionate MTL, Millionate MR-200, Millionate MR-400, Coronate L, Coronate HL, Coronate HX (the above are manufactured by Tosoh Corporation), Takenate D-101E, Takenate D-110N, Takenate D-120N, Takenate D-140N, Takenate D-160N, Takenate D-165N, Takenate D-170HN, Takenate D-178N, Takenate 500, Takenate 600 (the above are manufactured by Mitsui Chemicals, Inc.). Among these, Takenate D-101E is preferred.

[0156] The isocyanate crosslinking agents can be used alone or two or more of them can be used in combination.

[0157] As the peroxide, any peroxide that generates free radical active species by heating or light irradiation to crosslink the (meth)acrylic polymer (A) of the adhesive composition can be suitably used. However, considering operability and stability, peroxides with a 1-minute half-life temperature of 80°C to 160°C are preferably used, and peroxides with a 1-minute half-life temperature of 90°C to 140°C are more preferably used.

[0158] As peroxides, for example, the following can be mentioned: bis(2-ethylhexyl) peroxydicarbonate (1-minute half-life temperature: 90.6 °C), bis(4-tert-butylcyclohexyl) peroxydicarbonate (1-minute half-life temperature: 92.1 °C), di-sec-butyl peroxydicarbonate (1-minute half-life temperature: 92.4 °C), tert-butyl peroxyneodecanoate (1-minute half-life temperature: 103.5 °C), tert-hexyl peroxyneopentanoate (1-minute half-life temperature: 109.1 °C), tert-butyl peroxyneopentanoate (1-minute half-life temperature: 110.3 °C), dilauroyl peroxide (1-minute half-life temperature: 116.4 °C), dioctanoyl peroxide (1-minute half-life temperature: 117.4 °C), 1,1,3,3-tetramethylbutyl 2-ethylhexanoate peroxide (1-minute half-life temperature: 124.3 °C), bis(4-methylbenzoyl) peroxide (1-minute half-life temperature: 128.2 °C), benzoyl peroxide (1-minute half-life temperature: 130.0 °C), tert-butyl peroxyisobutyrate (1-minute half-life temperature: 136.1 °C), 1,1-bis(tert-hexylperoxy) cyclohexane (1-minute half-life temperature: 149.2 °C), etc. Among them, for the reason that the crosslinking reaction efficiency is particularly excellent, the following can be mentioned: bis(4-tert-butylcyclohexyl) peroxydicarbonate (1-minute half-life temperature: 92.1 °C), dilauroyl peroxide (1-minute half-life temperature: 116.4 °C), benzoyl peroxide (1-minute half-life temperature: 130.0 °C), etc.

[0159] When a crosslinking agent is incorporated into the adhesive composition, the amount of the crosslinking agent incorporated is, for example, 3 parts by weight or less, preferably 0.01 to 3 parts by weight, more preferably 0.02 to 2 parts by weight, and still more preferably 0.03 to 1 part by weight, based on 100 parts by weight of the (meth)acrylic polymer (A). When the amount of the crosslinking agent incorporated is 0.01 part by weight or more, the adhesive sheet 1 tends to be sufficiently crosslinked, and the durability and adhesive properties are improved. On the other hand, when the amount of the crosslinking agent incorporated is 3 parts by weight or less, there is a tendency to suppress the adhesive sheet 1 from becoming too hard and the durability from decreasing.

[0160] (Silane coupling agent)

[0161] The adhesive composition may further contain a silane coupling agent. Depending on the silane coupling agent, there is a tendency to improve the durability of the adhesive sheet 1. Specific examples of the silane coupling agent include, for example: epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutyl)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acryloyl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane, etc. The epoxy group-containing silane coupling agent is preferred.

[0162] The silane coupling agent may have multiple alkoxysilyl groups in the molecule. Specific examples of such silane coupling agents include, for example: X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, X-41-1810, X-40-2651, etc. manufactured by Shin-Etsu Chemical Co., Ltd. These silane coupling agents are not only less volatile, but also have a tendency to effectively improve the durability of the adhesive sheet 1. In particular, compared with glass, even when a transparent conductive layer (for example, an ITO layer) having a low reactivity with alkoxysilyl groups is used as the adherend, the durability of the adhesive sheet 1 is easily improved. The silane coupling agent having multiple alkoxysilyl groups in the molecule preferably has an epoxy group in the molecule, and more preferably has multiple epoxy groups. According to the silane coupling agent having multiple alkoxysilyl groups in the molecule and having an epoxy group, even when a transparent conductive layer is used as the adherend, the durability of the adhesive sheet 1 is more easily improved. Specific examples of such silane coupling agents include X-41-1053, X-41-1059A, X-41-1056 manufactured by Shin-Etsu Chemical Co., Ltd., and X-41-1056 containing a large amount of epoxy groups is particularly preferred.

[0163] The silane coupling agent can be used alone or in combination of two or more. From the viewpoint of improving the durability of the adhesive sheet 1, the blending amount of the silane coupling agent is, for example, 5 parts by weight or less, preferably 0.001 to 5 parts by weight, 0.01 to 1 part by weight, 0.02 to 1 part by weight, and more preferably 0.05 to 0.6 part by weight, based on 100 parts by weight of the (meth)acrylic polymer (A).

[0164] (Additive)

[0165] The adhesive composition may further contain additives other than those described above. Examples of the additives include: polyether compounds having reactive silyl groups, polyether compounds such as polyalkylene glycols (e.g., polypropylene glycol), powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulate matter, foils, solvents, etc. In addition, within a controllable range, redox types containing a reducing agent may also be used. In the adhesive composition, the blending amount of these additives is, for example, 5 parts by weight or less, may be 3 parts by weight or less, and further may be 1 part by weight or less, based on 100 parts by weight of the (meth)acrylic polymer (A).

[0166] (Physical properties of the adhesive sheet)

[0167] The thickness of the adhesive sheet 1 is not particularly limited, for example, it is about 1 to 100 μm, preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm. From the viewpoint of sufficiently ensuring the contact area with the conduction structure, the thickness of the adhesive sheet 1 can be 5 to 100 μm, can also be 5 to 50 μm, and further can be 10 to 35 μm.

[0168] The storage modulus G' of the adhesive sheet 1 at 25°C is not particularly limited. For example, it is 1.0×10 3 Pa or more, and can be 1.0×10 4 Pa or more, 3.0×10 4 Pa or more, 5.0×10 4 Pa or more, 7.0×10 4 Pa or more, 9.0×10 4 Pa or more, and further can be 1.0×10 5 Pa or more. The upper limit of the storage modulus G' of the adhesive sheet 1 at 25°C is not particularly limited. For example, it is 1.0×10 7 Pa or less. The adhesive sheet 1 having a high storage modulus G' is suitable for reducing the dimensional change amount of the optical laminate 10 in Test 1 described above.

[0169] The storage modulus G' of the adhesive sheet 1 at 25°C can be determined by the following method. First, prepare a measurement sample formed of the material constituting the adhesive sheet 1. The shape of the measurement sample is disk-shaped, the diameter of the bottom surface of the measurement sample is 8 mm, and the thickness is 1 mm. The measurement sample can be formed by punching a laminate in which a plurality of adhesive sheets 1 are laminated into a disk shape. Next, perform dynamic viscoelasticity measurement on the measurement sample. For dynamic viscoelasticity measurement, for example, "ARES-G2" manufactured by TA Instruments can be used. Based on the results of the dynamic viscoelasticity measurement, the storage modulus G' of the adhesive sheet 1 at 25°C can be determined. It should be noted that the conditions for dynamic viscoelasticity measurement are as described below.

[0170] ·Measurement conditions

[0171] Frequency: 1 Hz

[0172] Deformation mode: Torsion

[0173] Measurement temperature: -70°C to 150°C

[0174] Heating rate: 5°C / min

[0175] The surface resistance value of the adhesive sheet 1 is, for example, 1.0×10 7 Ω / sq to 1.0×10 12 Ω / sq, preferably 1.0×10 8 Ω / sq to 1.0×10 11 Ω / sq. The surface resistance value of the adhesive sheet 1 can be measured based on the method specified in JIS K6911:1995.

[0176] [Polarizing film]

[0177] The polarizing film 2 includes, for example, a polarizer and a protective film (transparent protective film). The protective film is disposed, for example, in contact with the main surface (the surface having the largest area) of the polarizer. As an example, the polarizing film 2 has two protective films, and the polarizer can be disposed between the two protective films. When the polarizer is disposed between the two protective films, there is a tendency to suppress the decolorization of the polarizer in a high-temperature and high-humidity environment.

[0178] The polarizer is not particularly limited. For example, examples include: a polarizer obtained by adsorbing a dichroic substance such as iodine or a dichroic dye onto a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or a partially saponified ethylene-vinyl acetate copolymer film and performing unidirectional stretching; a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Typically, the polarizer is formed of a polyvinyl alcohol-based film (the polyvinyl alcohol-based film includes a partially saponified ethylene-vinyl acetate copolymer film) and iodine.

[0179] When the polarizer contains iodine, from the viewpoint of heat resistance, the iodine content rate in the polarizer is, for example, 6.0 wt% or less, may be 5.0 wt% or less, and further may be 4.0 wt% or less. From the viewpoint of optical properties, the iodine content rate is, for example, 1.0 wt% or more, may be 1.5 wt% or more, and further may be 2.0 wt% or more. A polarizer with an iodine content rate of 6.0 wt% or less has a tendency to suppress dimensional changes in a high-temperature and high-humidity environment.

[0180] The thickness of the polarizer is generally 80 μm or less, may be 50 μm or less, 30 μm or less, 25 μm or less, 22 μm or less, and further may be 20 μm or less. When the thickness of the polarizer is small, there is a tendency for the amount of dimensional change of the optical laminate 10 in Test 1 described above to decrease. The lower limit of the thickness of the polarizer is not particularly limited, and is, for example, 1 μm or more, may be 5 μm or more, 6 μm or more, 10 μm or more, and further may be 15 μm or more.

[0181] As the material of the protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. can be used. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic olefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material of the protective film may be a thermosetting resin or an ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone. When the polarizing film 2 has two protective films, the materials of the two protective films may be the same or different from each other. For example, a protective film formed of a thermoplastic resin may be adhered to one main surface of the polarizer via an adhesive, and a protective film formed of a thermosetting resin or an ultraviolet curable resin may be adhered to the other main surface of the polarizer. The protective film may contain one or more arbitrary additives. Examples of additives include: ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, etc.

[0182] From the viewpoint of suppressing fluctuations in the surface resistance value of the adhesive sheet 1, the material of the protective film is preferably a cellulose resin, a (meth)acrylic resin, etc. As the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure is preferred. As the (meth)acrylic resin having a lactone ring structure, it is described in Japanese Patent Laid-Open No. 2000-230016, Japanese Patent Laid-Open No. 2001-151814, Japanese Patent Laid-Open No. 2002-120326, Japanese Patent Laid-Open No. 2002-254544, Japanese Patent Laid-Open No. 2005-146084, etc. The cellulose resin has a tendency to be able to effectively suppress cracks in the polarizer compared to the (meth)acrylic resin.

[0183] The thickness of the protective film can be appropriately determined. Generally, from the viewpoints of strength, workability such as processability, and film properties, etc., it is about 10 to 200 μm.

[0184] The polarizer and the protective film are laminated with an intervening layer such as an adhesive sheet, an adhesive, and an undercoat (primer coat). It is preferred to laminate the polarizer and the protective film without a gap through the intervening layer. The intervening layer is preferably an adhesive sheet. The adhesive forming the adhesive sheet is not particularly limited as long as it is optically transparent, and various forms of adhesives such as aqueous, solvent-based, hot melt, free radical curable, and cationic curable adhesives can be cited. An aqueous adhesive or a free radical curable adhesive is preferred.

[0185] The polarizing film 2 may also have a retardation film, a diffusion film, etc. instead of the protective film. As the retardation film, a retardation film having a front retardation of 40 nm or more and / or a thickness direction retardation of 80 nm or more can be cited. In the retardation film, generally, the front retardation is adjusted within the range of 40 to 200 nm, and the thickness direction retardation is adjusted within the range of 80 to 300 nm. Since the retardation film also functions as a protective film, when the polarizing film 2 includes a retardation film, thinning of the polarizing film 2 can be achieved.

[0186] [Method for manufacturing an optical laminate]

[0187] The optical laminate 10 can be manufactured, for example, by the following method. First, the adhesive composition described above is coated on a release liner and dried to form the adhesive sheet 1. By transferring the adhesive sheet 1 to the polarizing film 2, the optical laminate 10 can be produced. It should be noted that the optical laminate 10 can also be produced by coating the adhesive composition on the polarizing film 2 and drying it to form the adhesive sheet 1.

[0188] [Conductive paste]

[0189] As described above, in the present embodiment, the conductive paste is applied to a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by Test 1 is 80 μm or less to form a conduction structure. In addition, the elongation at break of the conductive paste obtained by Test 2 is 5% or more. As long as these requirements are met, the conductive paste is not particularly limited.

[0190] The conductive paste contains, for example, a metal and a binder. Specifically, the conductive paste contains metal particles dispersed in a binder. In the conductive paste, the metal functions as a conductive component. Examples of the metal include copper, silver, platinum, gold, aluminum, nickel, zinc, lithium, magnesium, cobalt, etc. In the conductive paste, the metal preferably contains silver.

[0191] From the viewpoint of conductivity, the content of the metal in the conductive paste is, for example, 40% by weight or more, can be 50% by weight or more, and further can be 55% by weight or more. The upper limit of the content of the metal is not particularly limited, for example, it is 70% by weight or less.

[0192] The binder contains, for example, a thermosetting resin. Examples of the thermosetting resin include polyester resin, silicone resin, polyurethane resin, etc. These resins are suitable for increasing the elongation at break obtained by Test 2. The binder preferably contains at least one selected from polyester resin and silicone resin as the thermosetting resin.

[0193] From the viewpoint of the durability of the conduction structure, the content of the binder in the conductive paste is, for example, 30% by weight or more, can be 40% by weight or more, and further can be 50% by weight or more. The upper limit of the content of the binder is not particularly limited, for example, it is 60% by weight or less.

[0194] It should be noted that when the binder contains an epoxy resin as the thermosetting resin, the elongation at break obtained by Test 2 tends to decrease. Therefore, in the binder, the content of the epoxy resin is preferably low, for example, 1% by weight or less, 0.1% by weight or less. The binder preferably does not substantially contain an epoxy resin.

[0195] Preferably, the adhesion of the conductive paste to the side surface 10c of the optical laminate 10 (specifically, the side surface of the adhesive sheet 1 and the side surface of the polarizing film 2) is high. As an example, the adhesion of the conductive paste obtained by the following Test 3 is preferably 0.1 N / 25 mm or more.

[0196] Test 3: Apply the conductive paste to an alkali-free glass to make a flat film. Paste the optical laminate 10 on the surface of the flat film via the adhesive sheet 1. Peel the optical laminate 10 from the flat film at a peeling angle of 90° and a peeling speed of 300 mm / min. Measure the force (adhesion) required at this time.

[0197] Specifically, Test 3 was conducted as follows. First, an alkali-free glass with a thickness of 0.5 mm (e.g., 1737 manufactured by Corning Incorporated) was prepared. A conductive paste was applied to the alkali-free glass and cured by heat treatment at, for example, 60°C to 150°C for 15 minutes to 5 hours to produce a flat film. Next, the optical laminate 10 (25 mm wide) was adhered to the surface of the flat film via the adhesive sheet 1. The adhesion of the optical laminate 10 was performed, for example, using a laminator. Next, the optical laminate 10 was bonded to the flat film by autoclave treatment at 50°C and 5 atm for 15 minutes.

[0198] Next, using a tensile testing machine (e.g., Autograph SHIMAZU AG-1 10KN), the optical laminate 10 was peeled off from the flat film at a peeling angle of 90° and a peeling speed of 300 mm / min (measurement length: 80 mm). At this time, the force required to peel the optical laminate 10 from the alkali-free glass was measured at intervals of 1 time / 0.5 s. The average value of the obtained measurement values was determined as the adhesion force (N / 25 mm).

[0199] The above adhesion force may be 1 N / 25 mm or more, or may be 5 N / 25 mm or more. The upper limit of the adhesion force is not particularly limited, for example, it is 20 N / 25 mm or less.

[0200] As described above, a conductive structure is formed by applying the conductive paste to a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by Test 1 is 80 μm or less. When forming the conductive structure, the conductive paste applied to the above portion may be cured as needed. For example, it can be cured by heat treatment of the conductive paste at 60°C to 150°C for 15 minutes to 5 hours.

[0201] <Embodiment of the image display panel>

[0202] An example of the image display panel of the present embodiment is shown in Figure 3A . Figure 3A The image display panel 100A includes an image display unit 30A, the above optical laminate 10, and a conductive structure 20. The conductive structure 20 is formed of the above conductive paste and contacts a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by Test 1 is 80 μm or less. As described above, the elongation at break of the conductive paste obtained by Test 2 is 5% or more. In the image display device including the image display panel 100A of the present embodiment, there is a tendency that breakage is less likely to occur between the conductive structure 20 and the optical laminate 10 even after being exposed to a high-temperature and high-humidity environment, and thus the antistatic performance is less likely to deteriorate.

[0203] [Optical laminate]

[0204] In the image display panel 100A, the optical laminate 10 is disposed, for example, closer to the visible side than the image display unit 30A. The optical laminate 10 is bonded to the image display unit 30A via an adhesive sheet 1, for example.

[0205] [Conduction structure]

[0206] As described above, the conduction structure 20 contacts a portion of the side surface 10c of the optical laminate 10 where the dimensional change amount obtained by Test 1 is 80 μm or less. The conduction structure 20 may contact the entire portion where the dimensional change amount is 80 μm or less, or may contact a part of this portion. The conduction structure 20 is preferably not in contact with the portion where the dimensional change amount is greater than 80 μm.

[0207] The conduction structure 20 preferably contacts at least the side surface of the adhesive sheet 1 in the side surface 10c of the optical laminate 10. Typically, it contacts both the side surface of the adhesive sheet 1 and the side surface of the polarizing film 2. A part of the conduction structure 20 may contact the main surface 10a of the optical laminate 10 (specifically, the main surface of the polarizing film 2). The conduction structure 20 extends, for example, along the thickness direction of the optical laminate 10, and one end thereof is connected to the image display unit 30A.

[0208] The ratio of the area of the side surface 10c of the optical laminate 10 covered by the conduction structure 20 to the entire area of the side surface 10c of the optical laminate 10 is, for example, 1% or more, preferably 3% or more. This ratio may be 99% or less, or may be 95% or less.

[0209] By bringing the conduction structure 20 into contact with the side surface 10c of the optical laminate 10, charging of the image display panel 100A can be suppressed. The conduction structure 20 is preferably connected to a ground electrode or the like.

[0210] [Image display unit]

[0211] The image display unit 30A includes, for example, an image forming layer 32, a first transparent substrate 31, and a second transparent substrate 33. The image forming layer 32 is disposed, for example, between the first transparent substrate 31 and the second transparent substrate 33, and is in contact with the first transparent substrate 31 and the second transparent substrate 33, respectively. The adhesive sheet 1 of the optical laminate 10 is in contact with the first transparent substrate 31 of the image display unit 30A, for example. Preferably, no conductive layer is disposed between the adhesive sheet 1 and the first transparent substrate 31.

[0212] The image forming layer 32 is, for example, a liquid crystal layer containing liquid crystal molecules that have a homogeneous alignment in the absence of an electric field. A liquid crystal layer containing such liquid crystal molecules is suitable for the In-Plane-Switching (IPS) mode. However, the liquid crystal layer can also be used for the Twisted Nematic (TN) type, Super Twisted Nematic (STN) type, π type, Vertical Alignment (VA) type, etc. In this specification, an image display unit equipped with a liquid crystal layer is sometimes referred to as a liquid crystal unit, and an image display panel equipped with a liquid crystal unit is sometimes referred to as a liquid crystal panel. It should be noted that the image forming layer 32 can also be an EL light-emitting layer.

[0213] The thickness of the image forming layer 32 is, for example, 1.5 μm to 4 μm.

[0214] As materials for the first transparent substrate 31 and the second transparent substrate 33, for example, glass and polymers can be cited. In this specification, a transparent substrate made of a polymer is sometimes referred to as a polymer film. As polymers constituting the transparent substrate, for example, polyethylene terephthalate, cycloolefin polymer, polycarbonate, etc. can be cited. The thickness of the transparent substrate made of glass is, for example, 0.1 mm to 1 mm. The thickness of the transparent substrate made of a polymer is, for example, 10 μm to 200 μm.

[0215] The image display unit 30A can further include other layers in addition to the image forming layer 32, the first transparent substrate 31, and the second transparent substrate 33. As other layers, for example, color filters, an easy-bonding layer, and a hard coat can be cited. The color filter is, for example, disposed closer to the visible side than the image forming layer 32, and is preferably located between the first transparent substrate 31 and the adhesive sheet 1 of the optical laminate 10. The easy-bonding layer and the hard coat are, for example, disposed on the surface of the first transparent substrate 31 or the second transparent substrate 33.

[0216] [Other components]

[0217] The image display panel 100A can further include other components in addition to the optical laminate 10, the conduction structure 20, and the image display unit 30A. As an example, the image display panel 100A can further include an additional adhesive sheet 5 and an additional polarizing film 6 as other components. The adhesive sheet 5 and the polarizing film 6 are located on the side of the image display unit 30A opposite to the optical laminate 10. The adhesive sheet 5 is, for example, in contact with the second transparent substrate 33 of the image display unit 30A, and the polarizing film 6 is attached to the image display unit 30A via the adhesive sheet 5. The polarizing film 6 is, for example, disposed such that its absorption axis is orthogonal to the absorption axis of the polarizing film 2.

[0218] The polarizing film 6 may be the polarizing film described above for the polarizing film 2. The polarizing film 6 may be the same as or different from the polarizing film 2.

[0219] The adhesive sheet 5 is formed of, for example, an adhesive composition. As the adhesive composition, the adhesive composition described above for the adhesive sheet 1 can be cited. The adhesive composition forming the adhesive sheet 5 may be the same as or different from the adhesive composition forming the adhesive sheet 1. The thickness of the adhesive sheet 5 is not particularly limited, and is, for example, about 1 to 100 μm, preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

[0220] The image display panel 100A may further include optical films such as a reflective film, a transflective film, a retardation film (λ / 2 wave plate, λ / 4 wave plate), a viewing angle compensation film, and a brightness enhancement film that can be used in an image display device as other components. The image display panel 100A may include one or more of these optical films.

[0221] The image display panel of the present embodiment may be an image display panel incorporating a touch sensing function. Examples of the image display panel incorporating a touch sensing function are shown in Figures 3B - 3F . Figures 3B - 3F The image display panels 100B to 100F of have an image display unit 30B to 30F including a touch sensing electrode portion. In these image display units, the touch sensing electrode portion is disposed between the first transparent substrate 31 and the second transparent substrate 33. The touch sensing electrode portion has functions of touch sensing and touch driving.

[0222] The image display panels 100B to 100F are so-called in-cell type image display panels, and the image display units 30B to 30F are so-called in-cell type image display units. However, in the image display unit, the touch sensing electrode portion may also be disposed closer to the visible side than the first transparent substrate 31. That is, the image display panel of the present embodiment may also be a so-called on-cell type image display panel, and the image display unit may also be a so-called on-cell type image display unit.

[0223] As shown in Figure 3B , 3C and 3F, the touch sensing electrode portion 35 has, for example, a touch sensing electrode 36 and a touch driving electrode 37. The touch sensing electrode 36 is an electrode for touch detection (reception). The touch sensing electrode 36 and the touch driving electrode 37 can be formed by various patterns independently. For example, when the image display unit 30B is flat, the touch sensing electrode 36 and the touch driving electrode 37 can be independently provided in the X-axis direction and the Y-axis direction, respectively, and formed into a pattern in which they intersect at right angles. In Figure 3B , 3CIn the 3F, in the touch sensing electrode portion 35, the touch sensing electrode 36 is disposed closer to the visible side than the touch driving electrode 37. However, the touch driving electrode 37 may also be disposed closer to the visible side than the touch sensing electrode 36.

[0224] In the touch sensing electrode portion 35, the touch sensing electrode 36 and the touch driving electrode 37 may be integrated. As an example, Figure 3D and 3E the image display units 30D and 30E shown have an electrode 38 formed by integrating the touch sensing electrode and the touch driving electrode.

[0225] In Figure 3B and 3D the touch sensing electrode portion 35 or the electrode 38 is disposed between the image forming layer 32 and the first transparent substrate 31 (closer to the visible side than the image forming layer 32). However, as in Figure 3C and 3E shown, the touch sensing electrode portion 35 or the electrode 38 may be disposed between the image forming layer 32 and the second transparent substrate 33 (closer to the illumination system side than the image forming layer 32).

[0226] In the touch sensing electrode portion 35, the touch sensing electrode 36 and the touch driving electrode 37 may also be non - connected to each other. For example, in Figure 3F the image display unit 30E shown, the touch sensing electrode 36 is disposed between the image forming layer 32 and the first transparent substrate 31, and the touch driving electrode 37 is disposed between the image forming layer 32 and the second transparent substrate 33.

[0227] The driving electrode in the touch sensing electrode portion (the touch driving electrode 37, or the electrode 38 formed by integrating the touch sensing electrode and the touch driving electrode) may also serve as a common electrode for controlling the image forming layer 32.

[0228] The touch sensing electrode 36 (capacitive sensor), the touch driving electrode 37, or the electrode 38 formed by integrating them that constitutes the touch sensing electrode portion 35 functions as a transparent conductive layer. The material of the transparent conductive layer is not particularly limited, and examples thereof include metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, tungsten, and alloys thereof. The material of the transparent conductive layer may also be an oxide of a metal such as indium, tin, zinc, gallium, antimony, zirconium, cadmium. Specific examples of the oxide include indium oxide, tin oxide, titanium oxide, cadmium oxide, and mixtures thereof. The material of the transparent conductive layer may also be a metal compound such as copper iodide. The material of the transparent conductive layer is preferably indium tin oxide (ITO) containing tin oxide, tin oxide containing antimony, etc., and particularly preferably ITO. When the material of the transparent conductive layer is ITO, the content of indium oxide in the transparent conductive layer is preferably 80 to 99% by weight, and the content of tin oxide is preferably 1 to 20% by weight.

[0229] The electrode (touch sensing electrode 36, touch driving electrode 37, or the electrode 38 formed by integrating them) that constitutes the touch sensing electrode portion 35 can be formed in the form of a transparent electrode pattern on the inner side (image forming layer 32 side) of the first transparent substrate 31 and / or the second transparent substrate 33 by a conventional method. The transparent electrode pattern is electrically connected to, for example, a lead wire formed at the end of the transparent substrate. The lead wire is connected to, for example, a controller IC (not shown). As the shape of the transparent electrode pattern, any shape corresponding to the use, such as a comb shape, a stripe shape, a diamond shape, etc., can be adopted. The thickness of the transparent electrode pattern is, for example, 10 nm to 100 nm. The width of the transparent electrode pattern is, for example, 0.1 mm to 5 mm.

[0230] <Embodiment of the image display device>

[0231] The image display device of the present embodiment includes, for example, the above-described image display panel and lighting system. In the image display device, the image display panel is disposed, for example, closer to the visible side than the lighting system. The lighting system has, for example, a backlight or a reflector and irradiates light on the image display panel.

[0232] The image display device may be an organic EL display or a liquid crystal display. However, the image display device is not limited to this example. The image display device may also be an electroluminescent (EL) display, a plasma display (PD), a field emission display (FED: Field Emission Display), etc. The image display device can be used for home appliance applications, in-vehicle applications, public information display (PID) applications, etc., and is preferably an in-vehicle display.

[0233] Examples

[0234] Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the examples shown below. It should be noted that parts and % in each example are based on weight. Hereinafter, all test conditions without special provisions are 23°C and 65% RH.

[0235] <Weight-average molecular weight of (meth)acrylic polymer>

[0236] In the following examples, the weight-average molecular weight (Mw) of the (meth)acrylic polymer was measured by GPC (gel permeation chromatography). The Mw / Mn of the (meth)acrylic polymer was also measured in the same manner.

[0237] · Analytical device: HLC-8120GPC manufactured by Tosoh Corporation

[0238] · Chromatographic column: G7000H manufactured by Tosoh Corporation XL +GMH XL +GMH XL

[0239] · Column size: Each 7.8mmφ×30cm, a total of 90cm

[0240] · Column temperature: 40°C

[0241] · Flow rate: 0.8 mL / min

[0242] · Injection volume: 100 μL

[0243] · Eluent: Tetrahydrofuran

[0244] · Detector: Differential refractometer (RI)

[0245] · Standard sample: Polystyrene

[0246] <Production of polarizing film F1>

[0247] (40 μm TAC film with HC)

[0248] In a resin solution obtained by dissolving a UV-curable resin monomer or oligomer containing urethane acrylate as a main component in butyl acetate (manufactured by DIC Corporation, trade name: UNIDIC 17-806, solid content concentration: 80%), 5 parts of a photopolymerization initiator (manufactured by BASF Corporation, trade name: IRGACURE 907) and 0.1 part of a leveling agent (manufactured by DIC Corporation, trade name: GRANDIC PC4100) were added per 100 parts of the solid content in the solution. Next, cyclopentanone and propylene glycol monomethyl ether were added to the solution at a ratio of 45:55 so that the solid content concentration in the solution reached 36%, and a hard coat forming material was prepared. The prepared hard coat forming material was applied to TJ40UL (manufactured by Fujifilm, raw material: triacetyl cellulose polymer, thickness: 40 μm) so that the thickness of the cured hard coat reached 7 μm, and a coating film was formed. The coating film was dried at 90 °C for 1 minute, and further irradiated with ultraviolet rays having a cumulative light amount of 300 mJ / cm 2 to cure the coating film and form a hard coat (HC), and a 40-μm TAC film with HC was prepared.

[0249] (30-μm acrylic film)

[0250] 8000 g of methyl methacrylate (MMA), 2000 g of methyl acrylate-2-(hydroxymethyl) (MHMA), 10000 g of 4-methyl-2-pentanone (methyl isobutyl ketone, MIBK), and 5 g of n-dodecyl mercaptan were added to a 30-L kettle-type reactor equipped with a stirring device, a temperature sensor, a condenser, and a nitrogen inlet tube. Nitrogen was introduced therein, and at the same time, the temperature was raised to 105 °C. When reflux occurred, 5.0 g of tert-butyl peroxyisopropyl carbonate (Kayacarbon BIC-7, manufactured by Kayaku AKZO Corporation) as a polymerization initiator was added, and at the same time, a solution composed of 10.0 g of tert-butyl peroxyisopropyl carbonate and 230 g of MIBK was added dropwise over 4 hours. At the same time, solution polymerization was carried out at about 105 to 120 °C under reflux, and further aging was carried out for 4 hours.

[0251] 30 g of a mixture of stearyl phosphate / distearyl phosphate (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) was added to the obtained polymer solution, and a cyclocondensation reaction was carried out at about 90 to 120 °C for 5 hours under reflux. Next, the obtained polymer solution was introduced into an exhaust-type twin-screw extruder (φ = 29.75 mm, L / D = 30) with a barrel temperature of 260 °C, a rotation speed of 100 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), 1 rear vent, and 4 front vents at a treatment speed of 2.0 kg / h in terms of resin amount. In this extruder, the cyclocondensation reaction and devolatilization were further carried out, and extrusion was performed to obtain transparent pellets of a polymer containing a lactone ring.

[0252] The obtained polymer containing a lactone ring was measured by dynamic TG, and a mass reduction of 0.17 mass% was detected. In addition, the weight-average molecular weight of this polymer containing a lactone ring was 133,000, the melt flow rate was 6.5 g / 10 min, and the glass transition temperature was 131 °C.

[0253] The obtained pellets were melt-kneaded and extruded with acrylonitrile-styrene (AS) resin (TOYOASAS20, manufactured by Toyo Styrene Co., Ltd.) at a mass ratio of 90 / 10 using a single-screw extruder (screw φ 30 mm) to obtain transparent pellets. The glass transition temperature of the obtained pellets was 127 °C.

[0254] Using a 50 mmφ single-screw extruder, the pellets were melt-extruded from a 400 mm-wide coat hanger die to produce a film with a thickness of 120 μm. Using a twin-screw stretching device, the produced film was stretched 2.0 times longitudinally and 2.0 times transversely at a temperature of 150 °C to obtain a stretched film with a thickness of 30 μm (30 μm acrylic film). As a result of measuring the optical properties of this stretched film, the total light transmittance was 93%, the in-plane retardation Δnd was 0.8 nm, and the thickness-direction retardation Rth was 1.5 nm.

[0255] (Polarizing film F1)

[0256] Between rollers with different speed ratios, while dyeing a polyvinyl alcohol film with a thickness of 45 μm in an iodine solution at a temperature of 30 °C and a concentration of 0.3% for 1 minute, it was stretched 3 times. Next, it was immersed in an aqueous solution at a temperature of 60 °C containing 4% boric acid and 10% potassium iodide by concentration for 0.5 minutes, while being stretched until the total stretching ratio reached 6 times. Next, after immersing it in an aqueous solution at a temperature of 30 °C containing 1.5% potassium iodide by concentration for 10 seconds for cleaning, it was dried at 50 °C for 4 minutes, thereby obtaining a polarizer with a thickness of 18 μm. A 40-μm TAC film with HC (on the side of the triacetyl cellulose film) after saponification was adhered to one side of this polarizer using a polyvinyl alcohol-based adhesive. Further, a 30-μm acrylic film was adhered to the other side of the polarizer using a polyvinyl alcohol-based adhesive. Thus, a polarizing film F1 was obtained.

[0257] <Fabrication of Polarizing Film F2>

[0258] Between rollers with different speed ratios, while dyeing a polyvinyl alcohol film with a thickness of 80 μm in an iodine solution at a temperature of 30 °C and a concentration of 0.3% for 1 minute, it was stretched 3 times. Next, it was immersed in an aqueous solution at a temperature of 60 °C containing 4% boric acid and 10% potassium iodide by concentration for 0.5 minutes, while being stretched until the total stretching ratio reached 6 times. Next, after immersing it in an aqueous solution at a temperature of 30 °C containing 1.5% potassium iodide by concentration for 10 seconds for cleaning, it was dried at 50 °C for 4 minutes, thereby obtaining a polarizer with a thickness of 28 μm. A 30-μm transparent protective film formed of a modified acrylic polymer having a lactone ring structure was adhered to one side of this polarizer using a polyvinyl alcohol-based adhesive. Further, a 47-μm transparent protective film with a hard coat (HC) formed on a triacetyl cellulose film (manufactured by Konica Minolta, trade name "KC4UY") was adhered to the other side of the polarizer. It was heated and dried in an oven set at 70 °C for 5 minutes, thereby fabricating a polarizing film F2.

[0259] <Fabrication of Polarizing Film F3>

[0260] (Thin Polarizer)

[0261] One side of a substrate of an amorphous isophthalic acid copolyethylene terephthalate (IPA copolyester) film (water absorption rate: 0.75%, Tg: 75°C, thickness: 100 μm) was subjected to corona treatment, and an aqueous solution containing polyvinyl alcohol (degree of polymerization: 4200, saponification degree: 99.2 mol%) and acetoacetylated polyvinyl alcohol (degree of polymerization: 1200, acetoacetylation rate: 4.6%, saponification degree: 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z200") in a ratio of 9:1 was coated on the corona-treated surface at 25°C and dried to form a polyvinyl alcohol-based resin layer with a thickness of 11 μm, thereby producing a laminate.

[0262] The obtained laminate was subjected to free-end unidirectional stretching (auxiliary stretching treatment in a gas atmosphere) to 2.0 times in the longitudinal direction (length direction) between rollers with different circumferential speeds in an oven at 120°C. Next, the laminate was immersed in an insolubilization bath at a liquid temperature of 30°C (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment). Next, it was immersed in a dyeing bath at a liquid temperature of 30°C (an aqueous iodine solution obtained by mixing 0.2 parts by weight of iodine and 1.0 parts by weight of potassium iodide with 100 parts by weight of water) for 60 seconds (dyeing treatment). Next, it was immersed in a crosslinking bath at a liquid temperature of 30°C (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment). Next, the laminate was immersed in an aqueous boric acid solution at a liquid temperature of 70°C (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water), and at the same time, unidirectional stretching was performed in the longitudinal direction (length direction) between rollers with different circumferential speeds so that the total stretching ratio reached 5.5 times (stretching treatment in an aqueous solution). Next, the laminate was immersed in a cleaning bath at a liquid temperature of 30°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment). Thus, an optical film laminate containing a polarizer with a thickness of 5 μm was obtained.

[0263] (Adhesive)

[0264] 45 parts by weight of acryloylmorpholine, 45 parts of 1,9-nonanediol diacrylate, 10 parts of an acrylic oligomer (ARUFONUP1190, manufactured by Toagosei Co., Ltd.) obtained by polymerizing (meth)acrylic acid monomers, 3 parts of a photoinitiator (IRGACURE907, manufactured by BASF), and 1.5 parts of a polymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) were mixed to prepare an ultraviolet curable adhesive.

[0265] (Polarizing film F3)

[0266] On the surface of the polarizer of the above optical film laminate, the ultraviolet curable adhesive was coated so that the thickness of the cured adhesive layer reached 1 μm, and a 25-μm TAC film with HC (on the triacetyl cellulose film side) was laminated. The 25-μm TAC film with HC was produced by the same method as the above 40-μm TAC film with HC. Next, ultraviolet rays were irradiated as active energy rays to cure the adhesive. For the ultraviolet irradiation, a metal halide lamp filled with gallium, an irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., a valve: V valve, a peak illuminance: 1600 mW / cm 2 and an accumulated irradiation dose of 1000 / mJ / cm 2 (wavelength 380 - 440 nm) were used. The illuminance of the ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Next, the amorphous PET substrate was peeled off, and a polarizing film F3 using a thin polarizer was produced. The optical properties of the obtained polarizing film F3 were: monomer transmittance 42.8% and degree of polarization 99.99%.

[0267] (Example 1)

[0268] [Preparation of (meth)acrylic polymer A1]

[0269] First, a monomer mixture containing 60 parts by weight of methoxyethyl acrylate, 39 parts by weight of butyl acrylate, and 1 part by weight of 4-hydroxybutyl acrylate was added to a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a condenser. Further, 0.1 part by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator and 100 parts by weight of ethyl acetate were added relative to 100 parts by weight of the monomer mixture. While slowly stirring the mixture, nitrogen was introduced into the flask for nitrogen replacement. The liquid temperature in the flask was maintained at around 55 °C and a polymerization reaction was carried out for 8 hours, thereby preparing a solution of (meth)acrylic polymer A1 having a weight average molecular weight (Mw) of 1.95 million and Mw / Mn = 3.9.

[0270] [Preparation of adhesive composition]

[0271] With respect to 100 parts by weight of the solid content of the solution of (meth)acrylic polymer A1, 5 parts by weight of 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (ELEXCEL AS-110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), 0.6 parts by weight of an isocyanate crosslinking agent (Coronate L, trimethylolpropane tolylene diisocyanate manufactured by Tosoh Corporation), and 0.1 parts by weight of benzoyl peroxide (NYPER BMT manufactured by NOF Corporation) were blended to prepare an adhesive composition.

[0272] [Fabrication of Optical Laminate]

[0273] Next, the above adhesive composition was coated on one surface of a polyethylene terephthalate film (release liner: MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) treated with a silicone-based release agent so that the thickness of the dried adhesive sheet reached 20 μm. The obtained coated film was dried at 155°C for 1 minute, whereby an adhesive sheet was formed on the surface of the release liner. Next, the adhesive sheet formed on the release liner was transferred to the acrylic film side of the above polarizing film F1 to fabricate an optical laminate (polarizing film with an adhesive sheet).

[0274] [Image Display Panel]

[0275] Next, the release liner was peeled off from the optical laminate and attached to the surface of the visible side of the in-cell liquid crystal cell. Next, a conductive paste (ELEPASTE NP-1, manufactured by Taiyo Ink Manufacturing Co., Ltd.) was coated on a portion ( Figure 2 portion S1) extending along the absorption axis direction of the polarizing film in the side surface of the optical laminate and cured, thereby forming a conduction structure. The conductive paste contains silver particles and a polyester resin, and the content rate of the conductive component (silver particles) is 57% by weight. The conduction structure is in contact with each side surface of the adhesive sheet and the polarizing film. The conduction structure is connected to an external ground electrode. Further, the lead wiring around the transparent electrode pattern inside the in-cell liquid crystal cell is connected to the controller IC. Thus, an image display panel (liquid crystal panel) of Example 1 having a built-in touch sensing function was fabricated.

[0276] (Examples 2 to 5, Comparative Examples 1 and 2)

[0277] As shown in Tables 1 to 2 below, the composition of the adhesive composition, the type of the polarizing film, and the type of the conductive paste were changed. In addition, image display panels (liquid crystal panels) of Examples 2 to 5, Comparative Examples 1 and 2 were produced by the same method as in Example 1. It should be noted that the conductive paste (SX-ECA48, manufactured by CEMEDINE Co., Ltd.) used in Example 2 contains silver particles and a polyester resin, and the content rate of the conductive component is 70 to 80% by weight. The conductive paste (TB3331D, manufactured by ThreeBond Co., Ltd.) used in Comparative Example 2 contains nickel particles and an epoxy resin, and the content rate of the conductive component is 46% by weight.

[0278] <Storage modulus of the adhesive sheet>

[0279] The storage modulus G' at 25°C was determined by performing dynamic viscoelasticity measurement on the adhesive sheets produced in the examples and comparative examples by the above method.

[0280] <Dimensional change amount of the optical laminate>

[0281] The above Test 1 was performed on the optical laminates produced in the examples and comparative examples, and the dimensional change amount L1 of the portion ([portion S1] extending in the absorption axis direction of the polarizing film) was determined. Figure 2 of portion S1) was determined.

[0282] <Elongation at break of the conductive paste>

[0283] The above Test 2 was performed on the conductive pastes used in the examples and comparative examples, and the elongation at break was determined.

[0284] <Durability of the image display panel>

[0285] [Presence or absence of breakage]

[0286] The image display panels of the examples and comparative examples were heat-treated for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH. After the heat treatment, the surface of the image display panel was observed by a scanning electron microscope (SEM) to confirm the presence or absence of breakage between the conduction structure and the optical laminate, and evaluation was performed according to the following criteria.

[0287] (Evaluation criteria)

[0288] A: No breakage occurred between the conduction structure and the optical laminate.

[0289] B: Local breakage occurred between the conduction structure and the optical laminate, but within a range where there is no problem in actual use.

[0290] C: Breakage occurred between the conduction structure and the optical laminate, and there is a problem in actual use.

[0291] It should be noted that Figures 4 - 7 are SEM images showing the surfaces of the image display panels of Examples 1 to 2 and Comparative Examples 1 to 2 after heat treatment. From these images, it can be seen that in Examples 1 to 2, almost no breakage occurred between the conduction structure 20 and the optical laminate 10. On the other hand, breakage occurred in Comparative Examples 1 to 2.

[0292] [Decolorization]

[0293] In addition, after the above heat treatment, the surface of the image display panel was observed by SEM, and decolorization (decolorization of the polarizing film) near the end of the optical laminate was confirmed and evaluated according to the following criteria.

[0294] (Evaluation Criteria)

[0295] A: The range of decolorization is 500 μm or less from the end of the optical laminate.

[0296] B: The range of decolorization exceeds 500 μm from the end of the optical laminate.

[0297] Table

[0298]

[0299] The abbreviations in Tables 1 and 2 are as follows.

[0300] MEA: 2-Methoxyethyl acrylate

[0301] BA: n-Butyl acrylate

[0302] HBA: 4-Hydroxybutyl acrylate

[0303] AIBN: Azobisisobutyronitrile, 2,2’-Azobis(2-methylpropionitrile) (manufactured by KISHIDA CHEMICAL CO., LTD.)

[0304] C / L: Trimethylolpropane / Toluene diisocyanate (manufactured by TOYOBO CO., LTD., Coronate L)

[0305] D110N: Trimethylolpropane / Phenylenediisocyanate (manufactured by MITSUI CHEMICALS, INC., Takenate D-110N)

[0306] BPO: Benzoyl peroxide (manufactured by NOF CORPORATION, NYPER BMT)

[0307] AS110: 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (ELEXCEL AS-110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0308] NP-1: Manufactured by Taiyo Ink Co., Ltd., ELEPASTE NP-1

[0309] SX-ECA48: Manufactured by CEMEDINE Co., Ltd., SX-ECA48

[0310] TB3331D: Manufactured by ThreeBond Co., Ltd., TB3331D

[0311] As can be seen from Table 2, compared with the comparative example, in the image display panel of the example where the conductive paste was applied to the portion of the side surface of the optical laminate with a dimensional change amount of 80 μm or less obtained by Test 1 to form a conduction structure, and further the elongation at break of the conductive paste obtained by Test 2 was 5% or more, the breakage between the conduction structure and the optical laminate in a high-temperature and high-humidity environment was sufficiently suppressed. It can be presumed that since the breakage between the conduction structure and the optical laminate of the image display panel of the example was suppressed, the antistatic performance was not easily reduced even after passing through a high-temperature and high-humidity environment.

[0312] Industrial Applicability

[0313] The kit for an image display panel of the present invention is suitable for manufacturing an image display panel whose antistatic performance is not easily reduced even after passing through a high-temperature and high-humidity environment.

Claims

1. A kit for an image display panel, comprising: An optical laminate having a polarizing film and an adhesive sheet, and Conductive paste, The conductive paste is coated on a portion of the side surface of the optical laminate where the dimensional change amount obtained by the following Test 1 is 80 μm or less to form a conduction structure, The elongation at break obtained by the following Test 2 for the conductive paste is 5% or more, Test 1: The optical laminate is pasted on a non-alkali glass via the adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85°C and a humidity of 85% RH, and the dimensional change amount of the optical laminate in the plane direction before and after the heat treatment is determined; Test 2: A flat film with a thickness of 2 mm is made from the conductive paste, and a test piece having a dumbbell shape No. 1 is made by punching the flat film. The test piece is set on a tensile testing machine, and a tensile test is performed under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min, and the elongation at break (elongation at break) when the test piece breaks is determined.

2. The kit according to claim 1, wherein, The elongation at break is 25% or more.

3. The kit according to claim 1, wherein, The conductive paste contains a metal and a binder.

4. The kit according to claim 3, wherein, The binder contains at least one selected from a polyester resin and a silicone resin.

5. The kit according to claim 3, wherein, The binder substantially does not contain an epoxy resin.

6. The kit according to claim 3, wherein, The metal contains silver.

7. The kit according to claim 1, wherein, The polarizing film has two protective films and a polarizer disposed between the two protective films.

8. The kit according to claim 7, wherein, The thickness of the polarizer is 6 μm or more.

9. The kit according to claim 1, wherein, The adhesive sheet is formed from an adhesive composition containing a (meth)acrylic polymer (A).

10. The kit according to claim 9, wherein, The (meth)acrylic polymer (A) has a structural unit derived from an ether group-containing monomer.

11. The kit according to claim 9, wherein, The adhesive composition further contains an antistatic agent.

12. The kit according to claim 1, wherein, The storage modulus G' of the adhesive sheet at 25 °C is 9.0×10 4 Pa or more.

13. The kit according to claim 1, wherein, The adhesive sheet is directly joined to the polarizing film.

14. An image display panel, comprising: an image display unit, an optical laminate including a polarizing film and an adhesive sheet, and a conduction structure formed of a conductive paste and in contact with a portion of a side surface of the optical laminate having a dimensional change amount of 80 μm or less obtained by the following Test 1, wherein the elongation at break obtained by the following Test 2 for the conductive paste is 5% or more, Test 1: The optical laminate is pasted on a non-alkali glass via the adhesive sheet, and heat treatment is performed for 240 hours under the conditions of a temperature of 85° C. and a humidity of 85% RH, and the dimensional change amount of the optical laminate in the plane direction before and after the heat treatment is determined; Test 2: A flat film with a thickness of 2 mm is made of the conductive paste, and a dumbbell No. 1 test piece is made by punching the flat film. The test piece is set on a tensile testing machine, and a tensile test is performed under the conditions of an initial chuck distance of 10 mm and a tensile speed of 300 mm / min, and the elongation at break (elongation at break) when the test piece breaks is determined.

15. The image display panel according to claim 14, which has a built-in touch sensing function.

Images