Optical film with an adhesive layer and an image display device including the optical film with an adhesive layer

Abstract

To provide an optical film with a pressure-sensitive adhesive layer in which glue chipping in irregularly shaped processed portions is significantly suppressed and peeling under high-temperature and high-humidity environments is significantly suppressed. The pressure-sensitive adhesive layer-attached optical film of the present invention comprises an optical film and a pressure-sensitive adhesive layer on one side of the optical film. The pressure-sensitive adhesive layer-attached optical film has an irregular shape other than rectangular, and the creep value of the pressure-sensitive adhesive layer at 85°C is 500 μm or less.

Description

Technical Field

[0001] The present invention relates to an optical film with an adhesive layer and an image display device including the optical film with the adhesive layer.

Background Art

[0002] In image display devices such as mobile phones and notebook personal computers, optical films are widely used to realize image display and / or improve the performance of the image display. The optical film typically has an adhesive layer provided thereon and is configured as an optical film with an adhesive layer, and can be bonded to an image display cell. In recent years, it may be desired to process the optical film into a shape other than a rectangle (shaped processing: for example, forming a notch and / or a through hole). However, in the shaped processing portion of the optical film with an adhesive layer, there is a problem that peeling (a phenomenon in which the end portion of the adhesive layer is missing) easily occurs. In addition, the adhesive layer has a problem of peeling in a high-temperature and high-humidity environment.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made to solve the above-described conventional problems, and its main object is to provide an optical film with an adhesive layer in which peeling is significantly suppressed in a shaped processing portion and peeling in a high-temperature and high-humidity environment is significantly suppressed.

Means for Solving the Problems

[0005] The optical film with an adhesive layer of the present invention has an optical film and an adhesive layer on one surface of the optical film. The optical film with an adhesive layer has a non-rectangular irregular shape, and the creep value of the adhesive layer at 85°C is 500 μm or less. In one embodiment, the creep value is 5 μm or more. In one embodiment, the thickness of the adhesive layer is 2 μm to 20 μm. In one embodiment, a separator is removably temporarily attached to the surface of the adhesive layer opposite to the optical film, and the peel force of the separator is 0.04 N / 50 mm to 0.5 N / 50 mm. In one embodiment, the optical film includes a polarizer. In one embodiment, the optical film further includes a retardation layer. According to another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned optical film with an adhesive layer.

Advantages of the Invention

[0006] According to the embodiment of the present invention, in an optical film with an adhesive layer having a non-rectangular irregular shape (irregular processing portion), by setting the creep value of the adhesive layer at 85°C within a predetermined range, lack of adhesion in the irregular processing portion is significantly suppressed, and an optical film with an adhesive layer in which peeling in a high-temperature and high-humidity environment is significantly suppressed can be realized.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0008] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. For ease of viewing, the drawings are schematically represented, and further, the ratios of length, width, thickness, etc., and angles, etc. in the drawings are different from the actual ones.

[0009] A. Outline of an optical film with an adhesive layer The optical film with an adhesive layer according to an embodiment of the present invention has an optical film and an adhesive layer on one surface of the optical film. In the embodiment of the present invention, the optical film with an adhesive layer has a non-rectangular irregular shape. As used herein, "having a non-rectangular irregular shape" means that the planar shape of the optical film with an adhesive layer has a shape other than a rectangle (including a rectangle and a rectangle with chamfered corners). The irregular shape is typically an irregularly processed portion that has been irregularly processed. Therefore, the "optical film with an adhesive layer having a non-rectangular irregular shape" (hereinafter sometimes referred to as an "irregular optical film") includes not only the case where the entire irregular optical film (i.e., the outer edge defining the planar shape of the film) is other than a rectangle, but also the case where an irregularly processed portion is formed in a portion spaced inward from the outer edge of a rectangular optical film. In such an irregularly processed portion, lack of adhesive is likely to occur. According to the embodiment of the present invention, such lack of adhesive can be significantly suppressed. Examples of the irregular shape (irregularly processed portion) include, as shown in FIGS. 1 and 2, a through hole and a cut portion that becomes a concave portion when viewed in plan. Representative examples of the concave portion include a shape approximated to a boat shape, a V-notch, and a U-notch. Another example of the irregular shape (irregularly processed portion) includes, as shown in FIGS. 3 and 4, a shape corresponding to an automotive meter panel. The shape is formed such that the outer edge is an arc along the rotation direction of the meter needle and includes a portion where the outer edge is a V-shaped (including a rounded shape) convex inward in the plane direction. Needless to say, the shape of the irregular shape (irregularly processed portion) is not limited to the illustrated examples. For example, the shape of the through hole can be any appropriate shape (e.g., an ellipse, a triangle, a quadrilateral, a pentagon, a hexagon, an octagon) according to the purpose, other than the substantially circular shape of the illustrated example. Further, the through hole can be provided at any appropriate position according to the purpose. The through hole may be provided at a substantially central portion of the longitudinal end of the rectangular optical film, at a predetermined position of the longitudinal end, at a corner of the optical film, as shown in FIG. 2; although not shown, it may be provided at the short-side end of the rectangular optical film; or as shown in FIG. 3 or FIG. 4, it may be provided at the central portion of the irregular optical film. Furthermore, the shapes of the illustrated examples may be appropriately combined according to the purpose.For example, through holes may be formed at any position of the shaped optical film in FIG. 1; V-notch and / or U-notch may be formed at any appropriate position on the outer edge of the shaped optical film in FIG. 3 or FIG. 4. Such a shaped optical film can be suitably used in image display devices such as automotive meter panels, smartphones, tablet PCs, or smartwatches.

[0010] In an embodiment of the present invention, the creep value of the adhesive layer at 85 °C is 500 μm or less, preferably 5 μm to 500 μm. If the creep value of the adhesive layer is within such a range, it is possible to realize an optical film with an adhesive layer in which glue shortage is significantly suppressed in the shaped processing part and peeling in a high-temperature and high-humidity environment is significantly suppressed. The configuration of the adhesive layer will be specifically described in section C below.

[0011] The glue shortage amount of the adhesive layer in the optical film with an adhesive layer (particularly, the adhesive layer in the shaped processing part) is preferably 80 μm or less, more preferably 65 μm or less, and still more preferably 50 μm or less. The smaller the glue shortage amount, the more preferable, and the lower limit can be, for example, 5 μm. In this specification, the "glue shortage amount" refers to the maximum value in the relevant direction of the adhesive layer that has fallen inward in the plane direction from the outer edge of the optical film (including the outer edge of the through hole).

[0012] In one embodiment, a separator is temporarily adhered to the surface of the adhesive layer opposite to the optical film in a peelable manner. Examples of the separator include plastic (e.g., polyethylene terephthalate (PET), polyethylene, polypropylene) films, non-woven fabrics, or papers surface-coated with a release agent such as a silicone-based release agent, a fluorine-based release agent, or a long-chain alkyl acrylate-based release agent. The thickness of the separator can be any appropriate thickness according to the purpose. The thickness of the separator is, for example, 10 μm to 100 μm.

[0013] The peel strength of the separator is preferably from 0.04 N / 50 mm to 0.5 N / 50 mm, more preferably from 0.07 N / 50 mm to 0.45 N / 50 mm. If the peel strength of the separator is within such a range, the amount of glue shortage in the adhesive layer (especially the adhesive layer in the shaped processed part) can be reduced. If the peel strength of the separator exceeds 0.5 N / 50 mm, the peelability of the separator may decrease and process defects may occur.

[0014] B. Optical film The optical film may be a film composed of a single layer or a laminate. Specific examples of the optical film composed of a single layer include a window film, a polarizer, and a retardation film. Specific examples of the optical film composed as a laminate include a polarizing plate (typically, a laminate of a polarizer and a protective film), a conductive film for a touch panel, a surface treatment film, and a laminate appropriately laminated for the purpose of these optical films composed of a single layer and / or optical films composed as a laminate (for example, a circular polarizing plate for antireflection, a polarizing plate with a conductive layer for a touch panel). Hereinafter, as representative examples of the optical film, the polarizing plate and the circular polarizing plate will be briefly described.

[0015] B-1. Polarizing plate The polarizing plate typically has a polarizer and a protective layer provided on one or both sides of the polarizer.

[0016] B-1-1. Polarizer The polarizer is typically composed of a resin film containing a dichroic substance. As the resin film, any appropriate resin film that can be used as a polarizer can be adopted. The resin film is typically a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film. The resin film may be a single-layer resin film or a laminate of two or more layers.

[0017] As a specific example of a polarizer composed of a single-layer resin film, there can be mentioned one obtained by subjecting a PVA-based resin film to a dyeing treatment with iodine and a stretching treatment (typically, uniaxial stretching). The above-mentioned dyeing with iodine is carried out, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment, or may be carried out while dyeing. Also, it may be dyed after stretching. If necessary, the PVA-based resin film is subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, etc. For example, by immersing the PVA-based resin film in water and washing it before dyeing, not only can the dirt on the surface of the PVA-based film and the blocking inhibitor be washed, but also the PVA-based resin film can be swollen to prevent uneven dyeing and the like.

[0018] As a specific example of a polarizer obtained using a laminate, there can be mentioned a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by coating a PVA-based resin solution on the resin substrate and drying it to form a PVA-based resin layer on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer; The stretching in this embodiment typically includes immersing the laminate in a boric acid aqueous solution and stretching it. Further, the stretching may further include, if necessary, air-stretching the laminate at a high temperature (for example, 95 ° C or higher) before stretching in the boric acid aqueous solution. The obtained laminate of the resin substrate / polarizer may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the laminate of the resin substrate / polarizer, and an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface and used. Details of such a method for manufacturing a polarizer are described, for example, in JP-A-2012-73580 and Japanese Patent No. 6470455. The entire descriptions of these publications are incorporated herein by reference.

[0019] The thickness of the polarizer is preferably 25 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 12 μm, and particularly preferably 3 μm to 8 μm. If the thickness of the polarizer is within such a range, curling during heating can be suppressed well, and good appearance durability during heating can be obtained.

[0020] The polarizer preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The single transmittance of the polarizer is preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

[0021] B-1-2. Protective layer The protective layer is formed of any suitable film that can be used as a protective layer for the polarizer. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, acetate-based and other transparent resins. Also included are thermosetting resins or ultraviolet curable resins such as (meth)acrylic-based, urethane-based, (meth)acrylic urethane-based, epoxy-based, silicone-based resins, etc. In addition, for example, glassy polymers such as siloxane-based polymers are also included. Also, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used. For example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the above resin composition.

[0022] On the protective layer (outer protective layer) on the side opposite to the adhesive layer, surface treatments such as hard coat treatment, antireflection treatment, anti-sticking treatment, antiglare treatment, etc. may be performed as necessary.

[0023] In one embodiment, the protective layer (inner protective layer) on the adhesive layer side is preferably optically isotropic. As used herein, "optically isotropic" means that the in-plane retardation Re(550) is from 0 nm to 10 nm and the retardation in the thickness direction Rth(550) is from -10 nm to +10 nm. In another embodiment, the inner protective layer may be a retardation film, a brightness enhancement film, a diffusion film, or the like.

[0024] The thickness of the protective layer can be any suitable thickness. The thickness of the protective layer is preferably from 5 μm to 200 μm, more preferably from 15 μm to 45 μm, and still more preferably from 20 μm to 40 μm. When surface treatment is performed, the thickness of the protective layer is the thickness including the thickness of the surface treatment layer.

[0025] B-2. Circular Polarizing Plate Typically, a circular polarizing plate includes a polarizer and a retardation layer. Practically, the polarizer can be included in the circular polarizing plate as a polarizing plate provided with protective layers on one or both sides. The retardation layer is typically disposed between the polarizing plate and the adhesive layer. The polarizer and the polarizing plate are as described in Section B-1 above.

[0026] The retardation layer may be a single layer or may have a laminated structure.

[0027] When the retardation layer is configured as a single layer, the retardation layer can typically function as λ / 4. In this case, the in-plane retardation Re(550) of the retardation layer is preferably from 100 nm to 190 nm, more preferably from 110 nm to 170 nm, and even more preferably from 130 nm to 160 nm. The angle formed between the slow axis of the retardation layer and the absorption axis of the polarizer is preferably from 40° to 50°, more preferably from 42° to 48°, and even more preferably about 45°. The retardation layer may exhibit an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light, or a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. In one embodiment, the retardation layer exhibits an inverse dispersion wavelength characteristic. In this case, Re(450) / Re(550) of the retardation layer is preferably 0.8 or more and less than 1, more preferably 0.8 or more and 0.95 or less.

[0028] When the retardation layer has a laminated structure, typically it has a two-layer structure of a first retardation layer and a second retardation layer. In this case, either the first retardation layer or the second retardation layer can function as a λ / 2 plate, and the other can function as a λ / 4 plate. For example, when the first retardation layer can function as a λ / 2 plate and the second retardation layer can function as a λ / 4 plate, Re(550) of the first retardation layer is preferably from 200 nm to 300 nm, more preferably from 230 nm to 290 nm, and even more preferably from 250 nm to 280 nm, and the angle formed between its slow axis and the absorption axis of the polarizer is preferably from 10° to 20°, more preferably from 12° to 18°, and even more preferably about 15°; Re(550) of the second retardation layer 22 is preferably from 100 nm to 190 nm, more preferably from 110 nm to 170 nm, and even more preferably from 130 nm to 160 nm, and the angle formed between its slow axis and the absorption axis of the polarizer is preferably from 70° to 80°, more preferably from 72° to 78°, and even more preferably about 75°.

[0029] The retardation layer can be composed of any suitable material as long as it can satisfy the above characteristics. For example, the retardation layer may be a resin film (typically, a stretched film), or an alignment and solidification layer of a liquid crystal compound (liquid crystal alignment and solidification layer). Representative examples of the resin constituting the resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used alone or in combination (for example, blended or copolymerized). When the retardation layer is composed of a resin film exhibiting reverse dispersion wavelength characteristics, a polycarbonate resin or a polyester carbonate resin (hereinafter, may be simply referred to as a polycarbonate resin) can be preferably used. Details of the polycarbonate resin preferably used for the retardation layer and the method for forming the retardation layer are described, for example, in JP-A-2014-10291, JP-A-2014-26266, JP-A-2015-212816, JP-A-2015-212817, and JP-A-2015-212818; specific examples of the liquid crystal compound and details of the method for forming the alignment and solidification layer are described, for example, in JP-A-2006-163343. The descriptions of these publications are incorporated herein by reference.

[0030] C. Adhesive layer C-1. Characteristics of the adhesive layer As described above, the adhesive layer has a creep value at 85°C of 500 μm or less, preferably 5 μm to 500 μm. In one embodiment, the creep value is preferably 200 μm to 450 μm, more preferably 220 μm to 420 μm. In another embodiment, the creep value is preferably 5 μm to 300 μm, more preferably 5 μm to 200 μm, still more preferably 10 μm to 100 μm, particularly preferably 15 μm to 70 μm, and most preferably 20 μm to 50 μm. If the creep value is within such a range, it is possible to significantly suppress glue shortage in the deformed processed portion and also significantly suppress peeling in a high-temperature and high-humidity environment. Even when the creep value is relatively large (for example, 200 μm or more), it is presumed that glue shortage can be suppressed by controlling the composition of the adhesive constituting the adhesive layer (for example, the type of base polymer (polarity, Tg, softness), molecular weight), cross-linked structure (for example, the type of cross-linking agent, distance between cross-linking points (molecular weight between cross-linking points), cross-linking density, uncross-linked component (sol fraction)). The creep value can be measured, for example, by the following procedure: A test sample cut out from the optical film with the adhesive layer is adhered to a support plate on a 10 mm × 10 mm bonding surface. With the support plate to which the test sample is adhered fixed, a load of 500 gf is applied vertically downward. The amount of displacement from the support plate 1 second and 3600 seconds after applying the load is measured, and is denoted as Cr1 and Cr 3600 respectively. Let Cr1 and Cr 3600 be such that ΔCr obtained from the following formula is taken as the creep value. ΔCr = Cr 3600 −Cr1

[0031] The adhesive layer preferably has a storage elastic modulus at 85°C of 1.0×10 4 Pa or more, preferably 2.0×10 4 Pa or more, more preferably 5.0×10 4 Pa or more, and still more preferably 1.0×10 5 Pa or more. If the storage elastic modulus is within such a range, it becomes easy to achieve the above-described desired creep value. On the other hand, the storage elastic modulus is, for example, 3.0×10 6It is below Pa. If the upper limit of the storage elastic modulus is within such a range, peeling of the adhesive layer in a high-temperature and high-humidity environment can be significantly suppressed.

[0032] The weight average molecular weight Mw of the base polymer in the adhesive composition forming the adhesive layer (details will be described later) is, for example, from 200,000 to 3,000,000, preferably from 1,000,000 to 2,500,000.

[0033] The gel fraction of the adhesive layer is preferably from 55% to 95%. In one embodiment, the gel fraction is preferably from 60% to 93%, more preferably from 80% to 91%. In this case, among the uncrosslinked components (sol fraction) of the adhesive composition, the weight average molecular weight Mw of the high molecular weight component derived from the base polymer (described later) is, for example, from 50,000 to 1,000,000, preferably from 50,000 to 500,000, more preferably from 100,000 to 400,000. The gel fraction is determined by (dry weight after immersion / dry weight before immersion) × 100 when the crosslinked adhesive is immersed in a predetermined solvent (for example, ethyl acetate) for 6 days and then dried. The weight average molecular weight Mw of the base polymer and the high molecular weight component derived from the base polymer among the uncrosslinked components (sol fraction) of the adhesive composition is determined, for example, from the value measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0034] The degree of swelling of the adhesive layer is preferably 35 times or less, more preferably from 10 times to 30 times, still more preferably from 11 times to 28 times, and particularly preferably from 12 times to 20 times. If the degree of swelling is within such a range, lack of glue in the deformed processing part can be significantly suppressed. The degree of swelling is determined by (weight after immersion / dry weight after immersion) when the crosslinked adhesive is immersed in a predetermined solvent (for example, ethyl acetate) for 6 days.

[0035] The storage elastic modulus, gel fraction, and swelling degree of the adhesive layer can be controlled by adjusting the composition of the adhesive constituting the adhesive layer (for example, the type of base polymer (polarity, Tg, softness), molecular weight), crosslinked structure (for example, the type of crosslinking agent, distance between crosslinking points (molecular weight between crosslinking points), crosslinking density), etc. More specifically, the type and combination of monomer components of the base polymer, polymerization conditions of the base polymer, type and amount of crosslinking agent used, etc. can be appropriately set.

[0036] The thickness of the adhesive layer is preferably 2 μm to 55 μm, more preferably 2 μm to 30 μm, still more preferably 2 μm to 20 μm, and particularly preferably 5 μm to 15 μm. When the thickness of the adhesive layer is within such a range, the lack of adhesive in the deformed processed part can be remarkably suppressed by the synergistic effect with the effect of controlling the creep value.

[0037] Typically, the adhesive layer is formed from an adhesive composition containing a (meth)acrylic polymer, a urethane polymer, a silicone polymer, or a rubber polymer as a base polymer. When a (meth)acrylic polymer is used as the base polymer, the adhesive layer is formed from, for example, an adhesive composition containing a (meth)acrylic polymer (A). The (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component.

[0038] C-2. (Meth)acrylic polymer (A) As described above, the (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component. The alkyl (meth)acrylate is preferably 50% by weight or more in all monomer components forming the (meth)acrylic polymer (A) from the viewpoint of improving the adhesiveness of the adhesive layer, and the balance can be arbitrarily set as the remainder of the monomers other than the alkyl (meth)acrylate. Note that (meth)acrylate refers to acrylate and / or methacrylate.

[0039] Examples of the alkyl (meth)acrylate that constitutes the main skeleton of the (meth)acrylic polymer (A) include those having a linear or branched alkyl group with 1 to 18 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, nonyl group, decyl group, isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. The alkyl (meth)acrylate can be used alone or in combination. The average carbon number of the alkyl group is preferably 3 to 10.

[0040] In addition to the alkyl (meth)acrylate, the (meth)acrylic polymer (A) may contain copolymerizable monomers such as a carboxyl group-containing monomer (a1) and a hydroxyl group-containing monomer (a2) as monomer components. The copolymerizable monomers can be used alone or in combination.

[0041] The carboxyl group-containing monomer (a1) is a compound that contains a carboxyl group in its structure and also 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 improving the adhesive properties of the adhesive layer.

[0042] When the carboxyl group-containing monomer (a1) is used as a monomer component, the content of the carboxyl group-containing monomer (a1) is usually 0.01% by weight or more and 10% by weight or less in all the monomer components that form the (meth)acrylic polymer (A).

[0043] The hydroxyl group-containing monomer (a2) is a compound that contains a hydroxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates 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, and 12-hydroxylauryl (meth)acrylate; and (4-hydroxymethylcyclohexyl)-methyl acrylate. Among these, from the viewpoint of improving the durability of the adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred.

[0044] When using the hydroxyl group-containing monomer (a2) as a monomer component, the content of the hydroxyl group-containing monomer (a2) is usually 0.01% by weight or more and 10% by weight or less in all the monomer components that form the (meth)acrylic polymer (A).

[0045] The (meth)acrylic polymer (A) preferably contains, as a monomer component, a monomer having an unsaturated carbon double bond with a glass transition temperature of the homopolymer of 0°C or higher. Examples of the monomer (a3) having an unsaturated carbon double bond with a glass transition temperature of the homopolymer of 0°C or higher include alkyl (meth)acrylate monomers and (meth)acrylic acid. The monomer (a3) is preferably a monomer having an unsaturated carbon double bond with a glass transition temperature of the homopolymer of 20°C or higher, and more preferably a monomer having an unsaturated carbon double bond with a glass transition temperature of the homopolymer of 40°C or higher.

[0046] In the (meth)acrylic polymer (A), the content ratio of the monomer (a3) is not particularly limited. The content is usually 0.1% by weight to 40% by weight, more preferably 1% by weight to 30% by weight. When two or more kinds of the monomer (a3) are used in combination, the content is the total content.

[0047] Examples of the monomer (a3) include linear alkyl (meth)acrylates such as methyl acrylate (Tg: 8°C), methyl methacrylate (Tg: 105°C), ethyl methacrylate (Tg: 65°C), n-propyl acrylate (Tg: 3°C), n-propyl methacrylate (Tg: 35°C), n-pentyl acrylate (Tg: 22°C), n-tetradecyl acrylate (Tg: 24°C), n-hexadecyl acrylate (Tg: 35°C), n-hexadecyl methacrylate (Tg: 15°C), n-stearyl acrylate (Tg: 30°C), and n-stearyl methacrylate (Tg: 38°C); branched-chain alkyl (meth)acrylates such as t-butyl acrylate (Tg: 43°C), t-butyl methacrylate (Tg: 48°C), i-propyl methacrylate (Tg: 81°C), and i-butyl methacrylate (Tg: 48°C); cyclic alkyl (meth)acrylates such as cyclohexyl acrylate (Tg: 19°C), cyclohexyl methacrylate (Tg: 65°C), isobornyl acrylate (Tg: 94°C), and isobornyl methacrylate (Tg: 180°C); and acrylic acid (Tg: 106°C). These can be used alone or in combination.

[0048] The copolymer monomer serves as a reaction point with a crosslinking agent when the pressure-sensitive adhesive composition contains the crosslinking agent described later. Since the carboxyl group-containing monomer and the hydroxyl group-containing monomer are highly reactive with the intermolecular crosslinking agent, they are preferably used to improve the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer. In addition, the carboxyl group-containing monomer is preferable in terms of achieving both durability and reworkability, and the hydroxyl group-containing monomer is preferable in terms of improving reworkability.

[0049] As a monomer component, other copolymerizable monomers (a4) may be further used. The other copolymerizable monomers (a4) have a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group. By using the other copolymerizable monomers (a4), the adhesiveness and heat resistance of the adhesive layer can be improved. The other copolymerizable monomers (a4) can be used alone or in combination.

[0050] By using an amino group-containing monomer or an amide group-containing monomer as the other copolymerizable monomers (a4), the adhesion of the adhesive layer can be improved. Examples of the amino group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of the amide group-containing monomer include acrylamide-based 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-methylol (meth)acrylamide, N-methylol-N-propane (meth)acrylamide, aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, mercaptomethyl (meth)acrylamide, and mercaptoethyl (meth)acrylamide; N-(meth)acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl group-containing lactam-based monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

[0051] Other copolymerizable monomer (a4) may be a polyfunctional monomer. By using a polyfunctional monomer, adjustment of the gel fraction of the pressure-sensitive adhesive layer and control of the cohesive force can be carried out. Examples of the polyfunctional monomer include hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate and other polyfunctional acrylates; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate, dipentaerythritol hexa(meth)acrylate.

[0052] Other copolymerizable monomers (a4) include, in addition to those described above, for example, (meth)acrylic acid 2-methoxyethyl, (meth)acrylic acid 2-ethoxyethyl, (meth)acrylic acid methoxytriethylene glycol, (meth)acrylic acid 3-methoxypropyl, (meth)acrylic acid 3-ethoxypropyl, (meth)acrylic acid 4-methoxybutyl, (meth)acrylic acid 4-ethoxybutyl and other (meth)acrylic acid alkoxyalkyl esters; cyclopolymerizable monomers such as methyl 2-(allyloxymethyl)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphate group-containing monomers; (meth)acrylic acid esters having an alicyclic hydrocarbon group such as (meth)acrylic acid cyclopentyl, (meth)acrylic acid cyclohexyl, and (meth)acrylic acid isobornyl; (meth)acrylic acid esters having an aromatic hydrocarbon group such as (meth)acrylic acid phenyl, (meth)acrylic acid phenoxyethyl, and (meth)acrylic acid benzyl; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ether; and vinyl chloride can be used.

[0053] The content of other copolymerizable monomers (a4) in the (meth)acrylic polymer is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 8% by mass or less, and particularly preferably 5% by mass or less.

[0054] C-3. Method for Producing (Meth)acrylic Polymer (A) The (meth)acrylic polymer (A) can be produced by any suitable method. Specific examples of the production method include various radical polymerizations such as radiation polymerization using electron beams or UV, solution polymerization, bulk polymerization, and emulsion polymerization. The resulting (meth)acrylic polymer (A) may be any of a random copolymer, a block copolymer, a graft copolymer, etc.

[0055] In solution polymerization, for example, ethyl acetate or toluene is used as the polymerization solvent. The reaction in solution polymerization is carried out, for example, by adding a polymerization initiator to the monomer component under an inert gas stream such as nitrogen, and usually at about 50°C to 70°C for about 5 hours to 30 hours.

[0056] Polymerization initiators, chain transfer agents, emulsifiers, etc. used in radical polymerization can be appropriately selected according to the purpose. The weight average molecular weight of the (meth)acrylic polymer (A) can be controlled by the amount of polymerization initiator and chain transfer agent used and the reaction conditions, and the type and amount used can be adjusted according to the desired weight average molecular weight.

[0057] Examples of the polymerization initiator include azo-based 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'-dimethyleneisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057); persulfates such as potassium persulfate and ammonium persulfate; peroxides such as di(2-ethylhexyl) peroxydicarbonate, di(4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; and redox initiators obtained by combining peroxides and reducing agents such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate.

[0058] The polymerization initiator can be used alone or in combination. The total amount of the polymerization initiator used is preferably about 0.005 to 1 part by weight, more preferably about 0.01 to 0.5 part by weight, based on 100 parts by weight of the monomer component.

[0059] Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, etc. The chain transfer agent may be used alone or in combination of two or more. The total amount of the chain transfer agent used is about 0.1 part by weight or less based on 100 parts by weight of the monomer component.

[0060] Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene-polyoxypropylene block polymer, etc. The emulsifier can be used alone or in combination.

[0061] Examples of the reactive emulsifier include emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced. Specific examples include Aqualon HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and Adeka Resorcin SE10N (manufactured by ADEKA). Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it has good water resistance, which is preferable. The amount of the emulsifier used is preferably 0.3 to 5 parts by weight, more preferably 0.5 to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. If the amount of the emulsifier used is within such a range, the polymerization stability and the mechanical stability of the resulting adhesive layer are excellent.

[0062] (Meth)acrylic polymer (A) can be produced by irradiating the monomer components with radiation such as electron beams or UV rays for polymerization when produced by radiation polymerization. When radiation polymerization is carried out by UV polymerization, a photoinitiator can be contained in the monomer components. Thereby, the polymerization time can be shortened. When radiation polymerization is carried out by electron beams, it is not particularly necessary to contain a photoinitiator in the monomer components.

[0063] As the photoinitiator, any suitable photoinitiator can be used. Specific examples include benzoin ether-based, acetophenone-based, α-ketol-based, photoactive oxime-based, benzoin-based, benzyl-based, benzophenone-based, ketal-based, and thioxanthone-based photoinitiators. The amount of the photoinitiator used is preferably 0.02 to 1.5 parts by weight, more preferably 0.1 to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. The photoinitiator can be used alone or in combination.

[0064] (Meta)acrylic polymer (A) has a weight-average molecular weight Mw of, for example, 200,000 to 3,000,000 as described above, preferably 1,000,000 to 2,500,000, and more preferably 1,200,000 to 2,500,000. If the weight-average molecular weight Mw is within such a range, an adhesive layer excellent in durability (especially heat resistance) can be obtained. When the weight-average molecular weight Mw exceeds 3,000,000, an increase in viscosity and / or gelation during polymer polymerization may occur.

[0065] (Meta)acrylic polymer (A) preferably has a polydispersity (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) of 5.0 or less, more preferably 1.05 to 5.0, and even more preferably 1.05 to 4.0. When the polydispersity (Mw / Mn) is large (for example, exceeding 5.0), there are many low-molecular-weight polymers. Even if an adhesive layer is formed so that the above creep value is the same, the amount of uncrosslinked polymers and oligomers (sol fraction) increases, the toughness of the adhesive layer decreases (becomes fragile), and there may be glue shortage during profiling or peeling in a high-temperature and high-humidity environment. The polydispersity (Mw / Mn) is measured by GPC (gel permeation chromatography) and determined from the value calculated by polystyrene conversion, similar to the weight-average molecular weight.

[0066] C-4. Silane coupling agent containing reactive functional group The adhesive composition can contain a silane coupling agent containing a reactive functional group. The reactive functional group in the silane coupling agent containing a reactive functional group is typically a functional group other than an acid anhydride group. Examples of the functional group other than the acid anhydride group include an epoxy group, a mercapto group, an amino group, an isocyanate group, an isocyanurate group, a vinyl group, a styryl group, an acetoacetyl group, a ureido group, a thiourea group, a (meta)acrylic group, a heterocyclic group, and combinations thereof. The silane coupling agent containing a reactive functional group can be used alone or in combination.

[0067] Examples of the reactive functional group-containing silane coupling agent include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; vinyl group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane; styryl group-containing silane coupling agents such as p-styryltrimethoxysilane; (meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane. Among these, epoxy group-containing silane coupling agents and mercapto group-containing silane coupling agents are preferred. As the epoxy group-containing silane coupling agent, for example, "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd. is commercially available.

[0068] As the reactive functional group-containing silane coupling agent, those having a plurality of alkoxysilyl groups in the molecule (oligomer-type silane coupling agents) can also be used. Specific examples include epoxy group-containing oligomer-type silane coupling agents manufactured by Shin-Etsu Chemical Co., Ltd., trade names "X-41-1053", "X-41-1059A", "X-41-1056", "X-40-2651"; mercapto group-containing oligomer-type silane coupling agents "X-41-1818", "X-41-1810", "X-41-1805". The oligomer-type silane coupling agent is difficult to volatilize and has a plurality of alkoxysilyl groups, so it can be effective in improving durability.

[0069] When a silane coupling agent containing a reactive functional group is blended in the adhesive composition, the blending amount of the silane coupling agent containing a reactive functional group is usually 0.001 part by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

[0070] C-5. Crosslinking agent The pressure-sensitive adhesive composition can contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent, a polyfunctional metal chelate, etc. can be used. Examples of the organic crosslinking agent include an isocyanate-based crosslinking agent, a peroxide-based crosslinking agent, an epoxy-based crosslinking agent, and an imine-based crosslinking agent. The polyfunctional metal chelate is one in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, etc. Examples of the atom in the organic compound that forms a covalent bond or a coordinate bond include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound, etc. Further, when the pressure-sensitive adhesive composition is a radiation-curable type, a polyfunctional monomer can be used as the crosslinking agent. Examples of the polyfunctional monomer include hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate and other polyfunctional acrylates; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate, dipentaerythritol hexa(meth)acrylate. The crosslinking agent can be used alone or in combination.

[0071] When the adhesive composition is a solvent type, as the crosslinking agent, an isocyanate-based crosslinking agent and / or a peroxide-based crosslinking agent are preferred. From the viewpoint of reducing paste shortage during processing, an isocyanate-based crosslinking agent is particularly preferred. From the viewpoint of suppressing peeling in a high-temperature and high-humidity environment, it is more preferable to use an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent in combination.

[0072] As the isocyanate-based crosslinking agent, for example, a compound having at least two isocyanate groups (including an isocyanate regenerable functional group in which the isocyanate group is temporarily protected by a blocking agent or oligomerization, etc.) can be used. For example, any suitable aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, etc. that can be used in a urethanization reaction are used.

[0073] Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate.

[0074] Examples of the alicyclic isocyanate include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethylxylylene diisocyanate.

[0075] Examples of the aromatic diisocyanate include, for example, phenylenediisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate.

[0076] Another example of the isocyanate-based crosslinking agent includes a multimer (dimer, trimer, pentamer, etc.) of the above diisocyanate, a urethane-modified product obtained by reacting with a polyhydric alcohol such as trimethylolpropane, a urea-modified product, a biuret-modified product, an alphanate-modified product, an isocyanurate-modified product, a carbodiimide-modified product.

[0077] Examples of the commercially available products of the isocyanate-based crosslinking agent include, for example, products named "Millionate MT", "Millionate MTL", "Millionate MR-200", "Millionate MR-400", "Coronate L", "Coronate HL", "Coronate HX" manufactured by Tosoh Corporation, and products named "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" manufactured by Mitsui Chemicals, Inc.

[0078] As the isocyanate-based crosslinking agent, aromatic polyisocyanate and its modified product, an aromatic polyisocyanate-based compound, aliphatic polyisocyanate and its modified product, an aliphatic polyisocyanate-based compound are preferable. The aromatic polyisocyanate-based compound is preferably used because of its good balance between the crosslinking rate and the pot life. As the aromatic polyisocyanate-based compound, tolylene diisocyanate and its modified product are particularly preferable.

[0079] As the peroxide crosslinking agent, any suitable peroxide crosslinking agent can be used as long as it generates radical active species by heating or light irradiation to promote the crosslinking of the base polymer ((meth)acrylic polymer (A)) of the pressure-sensitive adhesive composition. Preferably, it is a peroxide having a half-life temperature of 80°C to 160°C for 1 minute, and more preferably, it is a peroxide having a half-life temperature of 90°C to 140°C for 1 minute. Such peroxides are excellent in workability and stability.

[0080] Examples of the peroxide as described above include bis(2-ethylhexyl) peroxydicarbonate (half-life temperature for 1 minute: 90.6°C), bis(4-t-butylcyclohexyl) peroxydicarbonate (half-life temperature for 1 minute: 92.1°C), di-sec-butyl peroxydicarbonate (half-life temperature for 1 minute: 92.4°C), t-butyl peroxyneodecanoate (half-life temperature for 1 minute: 103.5°C), t-hexyl peroxypivalate (half-life temperature for 1 minute: 109.1°C), t-butyl peroxypivalate (half-life temperature for 1 minute: 110.3°C), dilauroyl peroxide (half-life temperature for 1 minute: 116.4°C), di-n-octanoyl peroxide (half-life temperature for 1 minute: 117.4°C), 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (half-life temperature for 1 minute: 124.3°C), bis(4-methylbenzoyl) peroxide (half-life temperature for 1 minute: 128.2°C), dibenzoyl peroxide (half-life temperature for 1 minute: 130.0°C), t-butyl peroxyisobutyrate (half-life temperature for 1 minute: 136.1°C), 1,1-di(t-hexylperoxy)cyclohexane (half-life temperature for 1 minute: 149.2°C). Among them, bis(4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide are preferred because of their particularly excellent crosslinking reaction efficiency.

[0081] Incidentally, the half-life of a peroxide is an index representing the decomposition rate of the peroxide, and refers to the time until the remaining amount of the peroxide becomes half. Regarding the decomposition temperature for obtaining the half-life at an arbitrary time and the half-life time at an arbitrary temperature, they are described in the manufacturer's catalog etc., for example, it is described in "Organic Peroxide Catalog 9th Edition (May 2003)" of NOF Corporation etc.

[0082] When a crosslinking agent is blended in the adhesive composition, the blending amount of the crosslinking agent is usually 0.01 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

[0083] When an isocyanate-based crosslinking agent is blended in the adhesive composition, the blending amount of the isocyanate-based crosslinking agent is usually 0.01 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer.

[0084] When a peroxide is blended in the adhesive composition, the blending amount of the peroxide is usually 0.01 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer. If it is within such a range, adjustment of processability, crosslinking stability, etc. is easy.

[0085] C-6. Other components The adhesive composition may contain a (meth)acrylic oligomer. The (meth)acrylic oligomer can be obtained by polymerizing the monomer components described in C-2 section with respect to the (meth)acrylic polymer alone or copolymerizing two or more of them. The type, number, combination, and polymerization molar ratio of the monomer components can be appropriately set according to the purpose and desired properties etc. The weight average molecular weight Mw of the (meth)acrylic oligomer is preferably 1000 to 8000, more preferably 2000 to 7000, and still more preferably 3000 to 6000. When a (meth)acrylic oligomer is blended in the adhesive composition, the blending amount of the (meth)acrylic oligomer is preferably 5 to 35 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer.

[0086] The pressure-sensitive adhesive composition can contain an ionic compound. As the ionic compound, any suitable ionic compound can be used. Examples of the ionic compound include those described in JP-A-2015-4861. Among them, (perfluoroalkylsulfonyl)imide lithium salts are preferred, and lithium bis(trifluoromethanesulfonylimide) is more preferred. The blending amount of the ionic compound can be appropriately set according to the purpose. For example, the blending amount of the ionic compound is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, still more preferably 3 parts by weight or less, and particularly preferably 1 part by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

[0087] The pressure-sensitive adhesive composition may contain an additive. Specific examples of the additive include 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, and foils. Also, within a controllable range, a redox system with a reducing agent added may be adopted. The type, number, combination, content, etc. of the additive can be appropriately set according to the purpose. The content of the additive is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and still more preferably 1 part by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

[0088] D. Image display device As described above, the optical film with a pressure-sensitive adhesive layer according to the embodiment of the present invention can be suitably applied to an image display device. Therefore, an image display device including the optical film with a pressure-sensitive adhesive layer is also included in the embodiment of the present invention. The image display device typically includes an image display cell and an optical film with a pressure-sensitive adhesive layer bonded to the image display cell via a pressure-sensitive adhesive layer. Examples of the image display device include a liquid crystal display device, an organic electroluminescence (EL) display device, and a quantum dot display device. Preferably, it is an organic EL display device because the effect of the optical film with a pressure-sensitive adhesive layer is remarkable.

Examples

[0089] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The evaluation items in the examples are as follows. Also, unless otherwise specified, "parts" and "%" in the examples are based on weight.

[0090] (1) Gel fraction The adhesives used in the examples and comparative examples were crosslinked, immersed in ethyl acetate for 6 days, and then dried. The gel fraction (%) was determined from the following formula. Gel fraction (%) = (dry weight after immersion / dry weight before immersion) × 100 (2) Swelling degree The adhesives used in the examples and comparative examples were crosslinked and immersed in ethyl acetate for 6 days. The swelling degree (%) was determined from the following formula. Swelling degree (times) = weight after immersion / dry weight after immersion (3) Separator peel strength The optical film with an adhesive layer (before irregular processing) used in the examples and comparative examples was cut into a size of 50 mm × 150 mm to obtain a measurement sample. Using a tensile testing machine (Autograph SHIMAZU AG-1 50N), the separator was peeled from the measurement sample at a tensile angle of 180° and a tensile speed of 300 mm / min, and the peel strength of the separator was measured. (4) Creep value The optical film with an adhesive layer obtained in the examples and comparative examples was cut into a size of 10 mm × 30 mm to obtain a test sample. The upper end portion (10 mm × 10 mm) of the test sample was adhered to a SUS plate through the adhesive layer and autoclaved at 50°C and 5 atm for 15 minutes. A precision hot plate installed so that the heating surface is in the vertical direction was heated to 85°C, and the SUS plate with the optical film with an adhesive layer adhered thereto was installed so that the surface without the adhesive layer adhered was in contact with the heating surface of the hot plate. After heating the SUS plate at 85°C for 5 minutes, a load of 500 gf was vertically applied downward to the lower end portion of the polarizing film with an adhesive layer. The displacement amounts between the optical film with an adhesive layer and the SUS plate 1 second and 3600 seconds after applying the load were measured, and Cr1 and Cr were measured respectively.3600 was used. ΔCr obtained from the following formula using Cr1 and Cr 3600 was taken as the creep value. ΔCr = Cr 3600 - Cr1 (5) Amount of adhesive shortage The state of the cross-section of the adhesive layer in the deformed processed part of the optical film with an adhesive layer obtained in the examples and comparative examples was observed with an optical microscope, and the length of the part where the loss of the adhesive layer from the outer edge inward in the plane direction was the largest was measured, and this length was taken as the amount of adhesive shortage (μm). (6) Durability The optical films with an adhesive layer obtained in the examples and comparative examples were cut into test samples with a size of 300 mm × 220 mm. At this time, they were cut out so that the absorption axis of the polarizer was in the long side direction. These test samples were laminated onto non-alkali glass (manufactured by Corning Inc., trade name "EG-XG") with a thickness of 350 mm × 250 mm × 0.7 mm using a laminator. Next, they were autoclave-treated at 50°C and 0.5 MPa for 15 minutes to adhere the adhesive layer to the glass. The test samples thus treated were subjected to a treatment for 500 hours in an atmosphere of 60°C / 95%RH. The appearance of the test samples after the treatment was visually evaluated according to the following criteria. ○: There are no appearance changes such as foaming or peeling. △: There is slight peeling or foaming at the ends, but there is no problem in practical use. ×: There is significant peeling at the ends, and there is a problem in practical use.

[0091] <Production Example 1: Preparation of Acrylic Polymer A1> A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate per 100 parts of this monomer mixture, and after introducing nitrogen gas while gently stirring for nitrogen substitution, the liquid temperature in the flask was maintained at around 55°C and a polymerization reaction was carried out for 8 hours to prepare a solution of acrylic polymer A1 having a weight average molecular weight (Mw) of 1.8 million and Mw / Mn = 4.8.

[0092] <Production Example 2: Preparation of Acrylic Polymer A2> A solution of acrylic polymer A2 with Mw of 2.3 million and Mw / Mn = 3.9 was prepared in the same manner as in Production Example 1, except that a monomer mixture containing 94.9 parts of butyl acrylate, 0.1 part of 2-hydroxyethyl acrylate, and 5 parts of acrylic acid was used.

[0093] <Production Example 3: Preparation of Acrylic Polymer (Partially Polymerized Monomer) A3> A four-necked flask equipped with a thermometer, a nitrogen gas inlet tube, a cooler, and a spindle connected to a B-type viscometer (rotational viscometer) was charged with a monomer mixture containing 65 parts of 2-ethylhexyl acrylate, 15 parts of N-vinylpyrrolidone, and 20 parts of 2-hydroxyethyl acrylate. Further, 0.05 part each of Ominirad 651 and Omnirad 184, which are photopolymerization initiators, was charged per 100 parts of this monomer mixture. Next, while rotating the spindle, nitrogen gas was introduced to replace the inside of the flask with nitrogen, and then ultraviolet light was irradiated until the viscosity of the polymerization system measured by the viscometer reached about 15 Pa·s to allow photopolymerization to proceed, thereby obtaining acrylic polymer A3 containing a partially polymerized product of the monomer group. Note that a BH type manufactured by Toki Sangyo Co., Ltd. was used for the viscometer, and the rotational speed of the spindle (rotor No. 5) was 10 rpm. Also, the liquid temperature inside the flask was maintained at 30°C.

[0094] <Production Example 4: Preparation of Acrylic Polymer A4> A solution of acrylic polymer A4 with Mw of 2.7 million and Mw / Mn = 3.8 was prepared in the same manner as in Production Example 1, except that a monomer mixture containing 91 parts of butyl acrylate, 6 parts of N-acryloylmorpholine, 0.3 part of 4-hydroxybutyl acrylate, and 2.7 parts of acrylic acid was used.

[0095] <Production Example 5: Preparation of Acrylic Polymer A5> A solution of acrylic polymer A5 with Mw of 1.54 million and Mw / Mn = 2.8 was prepared in the same manner as in Production Example 1, except that the polymerization time was set to 2 hours.

[0096] <Production Example 6: Preparation of Acrylic Oligomer B1> A monomer mixture containing 95 parts of butyl acrylate, 2 parts of acrylic acid, and 3 parts of methyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator and 140 parts of toluene were charged per 100 parts of this monomer mixture. While gently stirring, nitrogen gas was introduced and sufficient nitrogen substitution was performed. Then, the polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 70 °C to prepare a solution of acrylic oligomer B1. The Mw of the oligomer was 4500.

[0097] <Production Example 7: Preparation of Acrylic Oligomer B2> A monomer mixture containing 60 parts of dicyclopentanyl methacrylate and 40 parts of methyl methacrylate, 3.5 parts of α-thioglycerol as a chain transfer agent, and 100 parts of toluene as a polymerization solvent were mixed and stirred at 70 °C for 1 hour under a nitrogen atmosphere. Next, 0.2 part of AIBN was added as a thermal polymerization initiator and reacted at 70 °C for 2 hours, and then the temperature was raised to 80 °C and reacted for 2 hours. Thereafter, the reaction solution was heated to 130 °C to dry-remove toluene, the chain transfer agent, and unreacted monomers to obtain a (meth)acrylic oligomer B2.

[0098] <Production Example 8: Production of Polarizing Plate> (Production of HC-coated TAC Film) A resin solution in which an ultraviolet curable resin monomer or oligomer mainly composed of urethane acrylate is dissolved in butyl acetate (manufactured by DIC Corporation, trade name: Unidic 17-806, solid content concentration: 80%) was added with 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) per 100 parts of the solid content in the solution. Cyclopentanone and propylene glycol monomethyl ether were added to the solution in a ratio of 45:55 so that the solid content concentration in the solution became 36%, and a hard coat layer forming material was prepared. This hard coat layer forming material was applied onto a TAC film (manufactured by Fuji Film, product name: TJ40UL, thickness: 40 μm) so that the thickness of the cured hard coat layer became 7 μm to form a coating film. The coating film was dried at 90 °C for 1 minute, and further irradiated with ultraviolet rays having an integrated light amount of 300 mJ / cm 2 to cure the coating film and form a hard coat layer to produce an HC-attached TAC film. The obtained HC-attached TAC film was subjected to saponification treatment.

[0099] (Preparation of polarizing plate) A polyvinyl alcohol film with a thickness of 45 μm was stretched up to 3 times while being dyed in an iodine solution with a concentration of 0.3% at 30 °C for 1 minute between rolls with different speed ratios. Then, it was stretched up to a total stretching ratio of 6 times while being immersed in an aqueous solution containing 4% boric acid and 10% potassium iodide at 60 °C for 0.5 minute. Next, it was washed by immersing it in an aqueous solution containing 1.5% potassium iodide at 30 °C for 10 seconds, and then dried at 50 °C for 4 minutes to obtain a polarizer with a thickness of 18 μm. The HC-attached TAC film obtained above was bonded to one side of the polarizer, and a TAC film with a thickness of 40 μm (KC4CT, manufactured by Konica Minolta) subjected to saponification treatment was bonded to the other side with a polyvinyl alcohol-based adhesive to prepare a polarizing plate.

[0100] <Example 1> (Preparation of adhesive composition) To 100 parts by solid content of the solution of acrylic polymer A1 obtained in Production Example 1, 30 parts by solid content of acrylic oligomer B1 obtained in Production Example 4, 0.02 part of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Takenate D110N", trimethylolpropane / xylene diisocyanate adduct), 1 part of a peroxide crosslinking agent (manufactured by NOF Corporation, trade name "Niper BMT"), and 0.2 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were blended to prepare a solution of an acrylic pressure-sensitive adhesive composition.

[0101] (Production of Polarizing Plate with Adhesive Layer) The solution of the acrylic pressure-sensitive adhesive composition obtained above was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film, trade name "MRF38", separator film) treated with a silicone-based release agent so that the thickness of the dried adhesive layer was 50 μm, and dried at 155°C for 1 minute to form an adhesive layer on the surface of the separator film. Next, the adhesive layer formed on the separator film was laminated on the TAC film (KC4CT) side of the polarizing plate produced in Production Example 8 to produce an optical film with an adhesive layer (polarizing plate with an adhesive layer). The obtained optical film with an adhesive layer was subjected to profiling. At that time, profiling was performed using, as a workpiece, a laminate in which a surface protection film (manufactured by Nitto Denko Corporation, trade name "PPF-100T") was laminated on the HC-coated TAC film side of the obtained optical film with an adhesive layer. More specifically, a bundle stacked so that the stacked height was 10 mm was fixed with a clamp, and a through hole was drilled from the surface protection film side using an end mill with a blade diameter of 2.0 mm and cut so that the diameter of the hole part was 2.5 mm (processed into a shape corresponding to the center of the lower part of FIG. 2). The rotational speed of the blade during cutting was 2500 rpm, and the feed rate was 50 mm / min. The adhesive layer used for the production of the optical film with an adhesive layer was subjected to the evaluations in (1) and (2) above, the optical film with an adhesive layer before profiling was subjected to the evaluation in (3) above, and the profiled polarizing plate with an adhesive layer was subjected to the evaluations in (4) to (6) above. The results are shown in Table 1.

[0102] <Examples 2 to 6 and Examples 9 to 13> An optically functional film with a shaped adhesive layer was produced in the same manner as in Example 1, except that the composition of the adhesive composition forming the adhesive layer and the thickness of the adhesive layer were changed as shown in Table 1. The adhesive layer used in the production of the optically functional film with an adhesive layer, the optically functional film with an adhesive layer having a separator, and the polarizing plate with a shaped adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0103] <Example 7> An optically functional film with a shaped adhesive layer was produced in the same manner as in Example 6, except that the separator was replaced once before the shaping process. The adhesive layer used in the production of the optically functional film with an adhesive layer, the optically functional film with an adhesive layer having a separator, and the polarizing plate with a shaped adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0104] <Example 8> An optically functional film with a shaped adhesive layer was produced in the same manner as in Example 6, except that the separator was replaced twice. The adhesive layer used in the production of the optically functional film with an adhesive layer, the optically functional film with an adhesive layer having a separator, and the polarizing plate with a shaped adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0105] <Examples 14 and 15> (Preparation of Adhesive Composition) To 100 parts of the acrylic polymer (monomer partial polymer) A3 obtained in Production Example 3, 10 parts of the (meth)acrylic oligomer B2 obtained in Production Example 7, 0.1 part of a polyfunctional monomer as a crosslinking agent (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-HD-N", 1,6-hexanediol diacrylate), and 0.2 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were blended to prepare a mixture. Next, the above mixture was applied to the surface of a PET film (thickness: 38 μm) which is a base film (separator), and then a further PET film was placed on the coating film of the mixture, and the coating film was sandwiched between a pair of PET films. Next, the illuminance was 4 mW / cm 2 and the light quantity was 1200 mJ / cm 2The coating film was cured by irradiating ultraviolet rays under the irradiation conditions, and adhesive layers with the thicknesses shown in Table 1 (25 μm and 50 μm) were formed. After the formation of the adhesive layer, the additional PET film was peeled off to expose the adhesive layer, and an optical film with an adhesively formed layer that was deformed in the same manner as in Example 1 was produced. The adhesive layer used in the production of the optical film with an adhesively formed layer, the optical film with an adhesively formed layer having a separator, and the polarized plate with a deformed adhesively formed layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0106] <Examples 16 to 19 and Comparative Example 1> An optical film with a deformed adhesively formed layer was produced in the same manner as in Example 1, except that the composition of the adhesive composition for forming the adhesive layer and the thickness of the adhesive layer were changed as shown in Table 1. The adhesive layer used in the production of the optical film with an adhesively formed layer, the optical film with an adhesively formed layer having a separator, and the polarized plate with a deformed adhesively formed layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0107] <Example 20> An optical film with a deformed adhesively formed layer was produced in the same manner as in Example 19, except that the separator was replaced once. The adhesive layer used in the production of the optical film with an adhesively formed layer, the optical film with an adhesively formed layer having a separator, and the polarized plate with a deformed adhesively formed layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0108] <Example 21> (Production of Polarized Plate) A long roll of a polyvinyl alcohol film with a thickness of 30 μm (product name "PE3000" manufactured by Kuraray) was uniaxially stretched in the longitudinal direction by 5.9 times in the longitudinal direction using a roll stretching machine while simultaneously performing swelling, dyeing, cross-linking, and washing treatments, and finally a drying treatment was performed to produce a polarizer with a thickness of 12 μm. Specifically, the swelling treatment was carried out while stretching 2.2 times with pure water at 20°C. Next, the dyeing treatment was carried out while stretching 1.4 times in an aqueous solution at 30°C where the weight ratio of iodine to potassium iodide was adjusted so that the transmittance of the polarizing film to be produced was 45.0%, and the weight ratio of iodine to potassium iodide was 1:7. Further, for the cross-linking treatment, a two-stage cross-linking treatment was adopted. In the first-stage cross-linking treatment, stretching was carried out 1.2 times while treating in an aqueous solution in which boric acid and potassium iodide were dissolved at 40°C. The boric acid content in the aqueous solution for the first-stage cross-linking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. In the second-stage cross-linking treatment, stretching was carried out 1.6 times while treating in an aqueous solution in which boric acid and potassium iodide were dissolved at 65°C. The boric acid content in the aqueous solution for the second-stage cross-linking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Also, for the washing treatment, it was treated with an aqueous solution of potassium iodide at 20°C. The potassium iodide content in the aqueous solution for the washing treatment was 2.6% by weight. Finally, for the drying treatment, it was dried at 70°C for 5 minutes to obtain a polarizer. On both sides of the obtained polarizer, through a polyvinyl alcohol-based adhesive, a TAC film manufactured by Konica Minolta Inc. (product name: KC2UA, thickness: 25 μm) and an HC-TAC film having an HC layer on one side of the TAC film (thickness: 32 μm) were bonded respectively to obtain a polarizing plate 1 with protective films bonded to both sides of the polarizer.

[0109] (Production of the retardation layer A) 10 g of a polymerizable liquid crystal (manufactured by BASF, product name "Paliocolor LC242", represented by the following formula) showing a nematic liquid crystal phase and 3 g of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name "Irgacure 907") for the polymerizable liquid crystal compound were dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid). [Chemical formula] The surface of a polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed using a rubbing cloth to perform an alignment treatment. The conditions of the alignment treatment were as follows: the number of rubbing passes (number of rubbing rolls) was 1, the radius r of the rubbing roll was 76.89 mm, the rotational speed nr of the rubbing roll was 1500 rpm, and the film conveyance speed v was 83 mm / sec.

[0110] The alignment direction was set to be -75° when viewed from the viewing side with respect to the absorption axis direction of the polarizer when pasted to the polarizing plate. The coating liquid was coated on this aligned surface using a bar coater and heated and dried at 90°C for 2 minutes to align the liquid crystal compound. The liquid crystal layer thus formed was irradiated with light of 1 mJ / cm 2 to cure the liquid crystal layer, thereby forming a retardation layer A on the PET film. The thickness of the retardation layer A was 2 μm, and the in-plane retardation Re was 270 nm. Further, the retardation layer A had a refractive index distribution of nx > ny = nz.

[0111] (Fabrication of retardation layer B) The surface of a polyethylene terephthalate (PET) film (thickness: 38 μm) was rubbed using a rubbing cloth to perform an alignment treatment. The alignment direction was set to be -15° when viewed from the viewing side with respect to the absorption axis direction of the polarizer when pasted to the polarizing plate. The same liquid crystal coating liquid as described above was coated on this aligned surface, and the liquid crystal was aligned and cured in the same manner as above to form a retardation layer B on the PET film. The thickness of the retardation layer B was 1.2 μm, and the in-plane retardation Re was 140 nm. Further, the retardation layer B had a refractive index distribution of nx > ny = nz.

[0112] (Fabrication of polarizing plate with retardation layer) The TAC film surface of the above polarizing plate and the retardation layer A were bonded through an ultraviolet curable adhesive so that the angle between the absorption axis of the polarizing plate and the slow axis of the retardation layer A was 75°. Next, the retardation layer A and the retardation layer B were bonded through the same adhesive (thickness: 5 μm) as in Example 16 so that the angle between the absorption axis of the polarizing plate and the slow axis of the retardation layer B was 15°, thereby obtaining a polarizing plate with a retardation layer. Further, adhesive layers similar to those in Examples 1 to 20 and Comparative Example 1 were respectively formed on the outside of the retardation layer B. The obtained polarizing plate with a retardation layer was processed into a non-regular shape in the same manner as in Example 1 and subjected to the same evaluation as in Example 1. As a result, also in the polarizing plate with a retardation layer, those using the adhesive layers corresponding to Examples 1 to 20 had good adhesion and durability, and it was confirmed that those using the adhesive layer corresponding to Comparative Example 1 had large adhesion failure.

[0113]

Table 1

[0114] The abbreviations in Table 1 are as follows. Also, the blending amounts of the respective components in Table 1 are parts per 100 parts of the polymer. BA: Butyl acrylate MMA: Methyl methacrylate MA: Methyl acrylate AA: Acrylic acid HBA: 4-Hydroxybutyl acrylate HEA: 2-Hydroxyethyl acrylate 2EHA: 2-Ethylhexyl acrylate NVP: N-Vinylpyrrolidone DCPM: Dicyclopentanyl methacrylate ACMO: N-Acryloylmorpholine D110N: Trimethylolpropane / xylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Takenate D110N") C / L: Trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L") Peroxide: Peroxide crosslinking agent (manufactured by NOF Corporation, trade name "Niper BMT") A-HD-N: 1,6-Hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "A-HD-N") Si-cup agent: Epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") Antioxidant: Pentaerythritol tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate) (manufactured by BASF, trade name "Irganox1010")

[0115] <Evaluation> As is clear from Table 1, according to the examples of the present invention, it was actually possible to obtain an optical film with an adhesive layer in which lack of adhesion was significantly suppressed in the deformed processed portion and peeling in a high temperature and high humidity environment was suppressed. In Comparative Example 1 where the creep value of the adhesive layer was large, the amount of lack of adhesion was large. Furthermore, in the optical film with an adhesive layer having a separator, when the peeling force of the separator was small, the amount of lack of adhesion was large (for example, comparison between Examples 6 and 8 and comparison between Examples 19 and 20).

Industrial Applicability

[0116] The optical film with an adhesive layer of the present invention is suitably used for an image display device, and in particular, can be suitably used for an image display device having a deformed processed portion typified by an instrument panel of an automobile, a smartphone, a tablet PC, or a smart watch.

Claims

1. An optical film with an adhesive layer on one surface of the optical film, wherein the optical film with the adhesive layer has a non-rectangular irregular shape, the adhesive layer has a creep value of 5 μm to 50 μm and a swelling degree of 12 to 35 times when a load of 500 gf is applied at 85°C, the amount of adhesive shortage in the adhesive layer in the irregular shape is 80 μm or less, Optical film with an adhesive layer: Here, the swelling degree is obtained by immersing the adhesive constituting the adhesive layer in ethyl acetate for 6 days, (weight after immersion / dry weight after immersion); The amount of adhesive shortage is the length of the portion where the drop of the adhesive layer from the outer edge inward in the plane direction is the largest, observed with an optical microscope for the cross-sectional state of the adhesive layer in the irregular shape of the optical film with the adhesive layer.

2. The optical film with an adhesive layer according to Claim 1, wherein the thickness of the adhesive layer is 2 μm to 20 μm.

3. The storage elastic modulus of the pressure-sensitive adhesive layer at 85°C is 1.0×10 ４ Pa to 1.0×10 ６ Pa. The optical film with a pressure-sensitive adhesive layer according to claim 1 or 2.

4. The optical film with an adhesive layer according to any one of Claims 1 to 3, wherein the gel fraction of the adhesive layer is 55% to 95%.

5. The optical film with an adhesive layer according to any one of Claims 1 to 4, wherein the optical film contains a polarizer.

6. The optical film with an adhesive layer according to Claim 5, wherein the optical film further contains a retardation layer.

7. An image display device including the optical film with an adhesive layer according to any one of Claims 1 to 6.

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