WO2021060241A1

WO2021060241A1 - Adhesive layer-attached optical film and image display device including said adhesive layer-attached optical film

Info

Publication number: WO2021060241A1
Application number: PCT/JP2020/035691
Authority: WO
Inventors: 昌邦藤田; 遼太藤野; 雄祐外山
Original assignee: 日東電工株式会社
Priority date: 2019-09-26
Filing date: 2020-09-23
Publication date: 2021-04-01
Also published as: CN114302935B; JP2023052538A; CN114302935A; KR20220070441A

Abstract

Provided is an adhesive layer-attached optical film with which deficiency in adhesive in an irregular shape processing section is remarkably suppressed and peeling in a high-temperature and high-humidity atmosphere is remarkably suppressed. The adhesive layer-attached optical film lm according to the present invention has an optical film and an adhesive layer on one surface of the optical film. The adhesive layer-attached optical film has an irregular shape other than a rectangular shape, and the creep value of the adhesive layer is 500 μm or less at 85ºC.

Description

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

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

Optical films are widely used in image display devices such as mobile phones and notebook personal computers in order to realize image display and / or improve the performance of the image display. The optical film is typically configured as an optical film with an adhesive layer provided with an adhesive layer, and can be attached to an image display cell. In recent years, it may be desired to process an optical film into a shape other than a rectangle (deformed processing: for example, forming a notch and / or a through hole). However, there is a problem that adhesive chipping (a phenomenon in which the end portion of the pressure-sensitive adhesive layer is chipped) is likely to occur in the deformed portion of the optical film with the pressure-sensitive adhesive layer. Further, the adhesive layer has a problem of peeling in a high temperature and high humidity environment.

JP-A-2017-090896

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is to remarkably suppress adhesive chipping in the deformed processed portion and remarkably suppress peeling in a high temperature and high humidity environment. It is an object of the present invention to provide an optical film with an adhesive layer.

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 the pressure-sensitive adhesive layer has a shape other than a rectangle, and the creep value of the pressure-sensitive adhesive layer at 85 ° C. is 500 μm or less.
In one embodiment, the creep value is 5 μm or greater.
In one embodiment, the thickness of the pressure-sensitive adhesive layer is 2 μm to 20 μm.
In one embodiment, a separator is temporarily attached to the surface of the pressure-sensitive adhesive layer opposite to the optical film so that the separator can be peeled off, and the peeling force of the separator is 0.04 N / 50 mm to 0.5 N / 50 mm.
In one embodiment, the optical film comprises 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.

According to the embodiment of the present invention, in an optical film with an adhesive layer having a deformed shape (deformed portion) other than a rectangle, the creep value of the pressure-sensitive adhesive layer at 85 ° C. is set within a predetermined range, so that the glue is formed in the deformed portion. It is possible to realize an optical film with an adhesive layer in which chipping is remarkably suppressed and peeling is remarkably suppressed in a high temperature and high humidity environment.

It is a schematic plan view explaining an example of the deformed or deformed processed part in the optical film with a pressure-sensitive adhesive layer according to the embodiment of this invention. It is a schematic plan view explaining the deformation example of the deformed shape or the deformed shape processed part in the optical film with a pressure-sensitive adhesive layer according to the embodiment of this invention. It is a schematic plan view explaining the further deformation example of the deformed or deformed processed part in the optical film with an adhesive layer according to the embodiment of this invention. It is a schematic plan view explaining the further deformation example of the deformed or deformed processed part in the optical film with an adhesive layer according to the embodiment of this invention.

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. The drawings are schematically shown for easy viewing, and the ratios of length, width, thickness, etc., angles, etc. in the drawings are different from the actual ones.

A. Outline of Optical Film with Adhesive Layer The optical film with an adhesive layer according to the 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 shape other than a rectangle. As used herein, the term "having a variant shape other than a rectangle" means that the optical film with an adhesive layer has a shape other than a rectangle (including a rectangle and a case where corners are chamfered). The deformed shape is typically a deformed processed portion that has been deformed. Therefore, in the "optical film with an adhesive layer having a deformed shape other than a rectangular shape" (hereinafter, may be referred to as "deformed optical film"), the entire deformed optical film (that is, the outer edge that defines the plan view shape of the film) is used. This includes not only the case where the optical film is not rectangular, but also the case where the deformed portion is formed in a portion separated inward from the outer edge of the rectangular optical film. Where glue chipping is likely to occur in such a deformed processed portion, according to the embodiment of the present invention, such glue chipping can be remarkably suppressed. Examples of the deformed shape (deformed portion) include a through hole and a machined portion that becomes a concave portion when viewed in a plan view, as shown in FIGS. 1 and 2. Typical examples of the recess include a shape similar to a ship shape, a V-shaped notch, and a U-shaped notch. As another example of the irregular shape (deformed portion), as shown in FIGS. 3 and 4, there is a shape corresponding to the instrument panel of an automobile. The shape includes a portion in which the outer edge is formed in an arc shape along the rotation direction of the meter needle and the outer edge is V-shaped (including a round shape) convex inward in the plane direction. Needless to say, the shape of the deformed shape (deformed portion) is not limited to the illustrated example. For example, as the shape of the through hole, any appropriate shape (for example, ellipse, triangle, quadrangle, pentagon, hexagon, octagon) may be adopted depending on the purpose other than the substantially circular shape in the illustrated example. Further, the through hole is provided at an arbitrary appropriate position according to the purpose. As shown in FIG. 2, the through hole may be provided at a substantially central portion of the longitudinal end portion of the rectangular optical film, or may be provided at a predetermined position at the longitudinal end portion of the optical film. It may be provided at the corners; although not shown, it may be provided at the lateral end of the rectangular optical film; at the center of the deformed optical film, as shown in FIG. 3 or 4. It may be provided. Further, the shapes of the illustrated examples may be appropriately combined according to the purpose. For example, a through hole may be formed at any position on the deformed optical film of FIG. 1; a V-shaped notch and / or a U-shaped notch may be formed at any suitable position on the outer edge of the deformed optical film of FIG. 3 or FIG. It may be formed. Such a deformed optical film can be suitably used for an image display device such as an automobile meter panel, a smartphone, a tablet PC or a smart watch.

In the embodiment of the present invention, the creep value of the pressure-sensitive adhesive layer at 85 ° C. is 500 μm or less, preferably 5 μm to 500 μm. When the creep value of the pressure-sensitive adhesive layer is within such a range, an optical film with a pressure-sensitive adhesive layer is realized in which adhesive chipping is remarkably suppressed in the deformed portion and peeling is remarkably suppressed in a high temperature and high humidity environment. can do. The structure of the pressure-sensitive adhesive layer will be specifically described in Section C, which will be described later.

The amount of adhesive chipping of the pressure-sensitive adhesive layer (particularly, the pressure-sensitive adhesive layer in the deformed portion) in the optical film with the pressure-sensitive adhesive layer is preferably 80 μm or less, more preferably 65 μm or less, and further preferably 50 μm or less. The smaller the amount of adhesive chipping, the more preferable, and the lower limit thereof can be, for example, 5 μm. In the present specification, the "adhesive chipping amount" means the maximum value in the direction of the pressure-sensitive adhesive layer missing inward in the plane direction from the outer edge of the optical film (including the outer edge of the through hole).

In one embodiment, a separator is temporarily attached to the surface of the pressure-sensitive adhesive layer opposite to the optical film so that it can be peeled off. Examples of the separator include a plastic (for example, polyethylene terephthalate (PET), polyethylene, polypropylene) film, a non-woven fabric, or a surface-coated plastic (for example, polyethylene terephthalate (PET), polyethylene, polypropylene) film, which is 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. Examples include paper. As the thickness of the separator, any appropriate thickness can be adopted depending on the purpose. The thickness of the separator is, for example, 10 μm to 100 μm.

The peeling force of the separator is preferably 0.04N / 50mm to 0.5N / 50mm, and more preferably 0.07N / 50mm to 0.45N / 50mm. When the peeling force of the separator is within such a range, the amount of adhesive chipping of the pressure-sensitive adhesive layer (particularly, the pressure-sensitive adhesive layer in the deformed portion) can be reduced. If the peeling force of the separator exceeds 0.5 N / 50 mm, the peelability of the separator is lowered and a process defect may occur.

B. Optical film The optical film may be a film composed of a single layer or a laminated body. 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 configured as a laminate include a polarizing plate (typically, a laminate of a polarizing element and a protective film), a conductive film for a touch panel, a surface treatment film, and a single layer thereof. Examples thereof include a laminated body (for example, a circular polarizing plate for antireflection, a polarizing plate with a conductive layer for a touch panel) in which an optical film formed as an optical film and / or an optical film formed as a laminated body is appropriately laminated according to a purpose. Hereinafter, a polarizing plate and a circular polarizing plate will be briefly described as typical examples of the optical film.

B-1. Polarizing plate A polarizing plate typically has a polarizing element and a protective layer provided on one side or both sides of the polarizing element.

B-1-1. Polarizer The polarizer is typically composed of a resin film containing a dichroic substance. As the resin film, any suitable 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 laminated body having two or more layers.

Specific examples of the polarizer composed of a single-layer resin film include those obtained by subjecting a PVA-based resin film to a dyeing treatment with iodine and a stretching treatment (typically, uniaxial stretching). The dyeing with iodine is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment or while dyeing. Alternatively, it may be stretched and then dyed. If necessary, the PVA-based resin film is subjected to a swelling treatment, a cross-linking treatment, a cleaning treatment, a drying treatment and the like. For example, by immersing the PVA-based resin film in water and washing it with water before dyeing, not only can the stains on the surface of the PVA-based film and the blocking inhibitor be washed, but also the PVA-based resin film is swollen to cause uneven dyeing. Etc. can be prevented.

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin. Examples thereof include a polarizer obtained by using a laminate with a PVA-based resin layer coated and formed on a base material. The polarizer obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying the resin base material. It is produced by forming a PVA-based resin layer on the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further include, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled off from the resin base material / polarizer laminate. Then, an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface. Details of the method for producing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The entire description of these publications is incorporated herein by reference.

The thickness of the polarizer is preferably 25 μm or less, more preferably 1 μm to 12 μm, further preferably 3 μm to 12 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance 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 further preferably 99.9% or more.

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, and polysulfone-based. , Polystyrene-based, polycarbonate-based, polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Further, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also 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, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the above resin composition.

The protective layer (outer protective layer) on the opposite side of the adhesive layer may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, anti-glare treatment, etc., if necessary.

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

Any appropriate thickness can be adopted as the thickness of the protective layer. The thickness of the protective layer is preferably 5 μm to 200 μm, more preferably 15 μm to 45 μm, and even more preferably 20 μm to 40 μm. When the surface treatment is applied, the thickness of the protective layer is the thickness including the thickness of the surface treatment layer.

B-2. Circular polarizing plate A circular polarizing plate typically includes a polarizer and a retardation layer. Practically, the polarizer can be included in a circular polarizing plate as a polarizing plate having protective layers on one side or both sides. The retardation layer is typically arranged between the polarizing plate and the pressure-sensitive adhesive layer. The polarizer and the polarizing plate are as described in Section B-1 above.

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

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 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 130 nm to 160 nm. The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is preferably 40 ° to 50 °, more preferably 42 ° to 48 °, and even more preferably about 45 °. The retardation layer may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, or may exhibit a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. It is also possible to exhibit a flat wavelength dispersion characteristic in which the phase difference value hardly changes depending on the wavelength of the measurement light. In one embodiment, the retardation layer exhibits inverse dispersion wavelength characteristics. In this case, the Re (450) / Re (550) of the retardation layer is preferably 0.8 or more and less than 1, and more preferably 0.8 or more and 0.95 or less.

When the retardation layer has a laminated structure, it typically has a two-layer structure of a first retardation layer and a second retardation layer. In this case, either one of 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 preferable. Is 200 nm to 300 nm, more preferably 230 nm to 290 nm, still more preferably 250 nm to 280 nm, and the angle formed by the slow axis thereof and the absorption axis of the polarizer is preferably 10 ° to 20 °. More preferably 12 ° to 18 °, even more preferably about 15 °; the Re (550) of the second retardation layer 22 is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm. It is more preferably 130 nm to 160 nm, and the angle formed by the slow axis and the absorber absorption axis is preferably 70 ° to 80 °, more preferably 72 ° to 78 °, and further preferably about 75 °. °.

The retardation layer can be made of any suitable material as long as the above characteristics can be satisfied. For example, the retardation layer may be a resin film (typically a stretched film) or an oriented solidified layer of a liquid crystal compound (liquid crystal oriented solidified layer). Typical examples of resins constituting the resin film are polycarbonate-based resin, polyester carbonate-based resin, polyester-based resin, polyvinyl acetal-based resin, polyarylate-based resin, cyclic olefin-based resin, cellulose-based resin, polyvinyl alcohol-based resin, and polyamide. Examples thereof include based resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used alone or in combination (eg, blending, copolymerizing). When the retardation layer is composed of a resin film exhibiting inverse dispersion wavelength characteristics, a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter, may be simply referred to as a polycarbonate-based resin) can be preferably used. Details of the polycarbonate resin that can be suitably used for the retardation layer and the method for forming the retardation layer are described in, for example, JP-A-2014-10291, JP-A-2014-226666, JP-A-2015-212816, It is described in Japanese Patent Application Laid-Open No. 2015-212817 and Japanese Patent Application Laid-Open No. 2015-212818; specific examples of liquid crystal compounds and details of a method for forming an oriented solidified layer are described in, for example, Japanese Patent Application Laid-Open No. 2006-163343. The descriptions in these publications are incorporated herein by reference.

C. Adhesive layer C-1. Characteristics of the pressure-sensitive adhesive layer As described above, the pressure-sensitive adhesive layer has a creep value of 500 μm or less at 85 ° C., 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 particularly preferably 20 μm. It is ~ 50 μm. When the creep value is in such a range, it is possible to remarkably suppress the adhesive chipping of the deformed processed portion and remarkably suppress the peeling in a high temperature and high humidity environment. Even when the creep value is relatively large (for example, 200 μm or more), the composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer (for example, the type of base polymer (polarity, Tg, softness), molecular weight), It is presumed that adhesive chipping can be suppressed by controlling the crosslinked structure (for example, the type of the crosslinking agent, the distance between the crosslinking points (molecular weight between the crosslinking points), the crosslinking density, and the uncrosslinked component (sol content)). The creep value can be measured, for example, by the following procedure: a test sample cut out from an optical film with an adhesive layer is attached to a support plate at a joint surface of 10 mm × 10 mm. With the support plate to which the test sample is attached fixed, a load of 500 gf is applied vertically downward. The amount of deviation from the support plate after 1 second and 3600 seconds after applying the load is measured and designated as _{Cr 1} _{and Cr 3600} , respectively. Let ΔCr obtained from Cr ₁ and Cr ₃₆₀₀ by the following formula be the creep value.
ΔCr = Cr _3600- Cr ₁

The adhesive layer has a storage elastic modulus at 85 ° C. of preferably 1.0 × 10 ⁴ Pa or more, preferably 2.0 × 10 ⁴ Pa or more, and more preferably 5.0 × 10 ⁴ Pa or more. , and still more preferably 1.0 × ¹⁰ 5 Pa or more. When the storage elastic modulus is in such a range, it becomes easy to realize the desired creep value. On the other hand, the storage modulus is less for example 3.0 × ¹⁰ 6 Pa. When the upper limit of the storage elastic modulus is in such a range, peeling of the pressure-sensitive adhesive layer in a high-temperature and high-humidity environment can be remarkably suppressed.

The weight average molecular weight Mw (details will be described later) of the base polymer in the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer is, for example, 200,000 to 3 million, preferably 1 million to 2.5 million.

The gel fraction of the pressure-sensitive adhesive layer is preferably 55% to 95%. In one embodiment, the gel fraction is preferably 60% to 93%, more preferably 80% to 91%. In this case, among the uncrosslinked components (sol content) of the pressure-sensitive adhesive composition, the weight average molecular weight Mw (described later) of the high molecular weight component derived from the base polymer is, for example, 50,000 to 1,000,000, preferably 50,000 to 50. It is 10,000, more preferably 100,000 to 400,000. The gel fraction is determined by (dry weight after immersion / dry weight before immersion) × 100 when the crosslinked pressure-sensitive 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 high molecular weight component derived from the base polymer among the uncrosslinked components (sol content) of the base polymer and the pressure-sensitive adhesive composition is measured by, for example, gel permeation chromatography (GPC) and calculated by polystyrene conversion. It is calculated from the calculated value.

The degree of swelling of the pressure-sensitive adhesive layer is preferably 35 times or less, more preferably 10 times to 30 times, further preferably 11 times to 28 times, and particularly preferably 12 times to 20 times. When the degree of swelling is within such a range, it is possible to remarkably suppress the adhesive chipping of the deformed portion. The degree of swelling is determined by immersing the crosslinked pressure-sensitive adhesive in a predetermined solvent (for example, ethyl acetate) for 6 days (weight after immersion / dry weight after immersion).

The storage elasticity, gel fraction and swelling degree of the pressure-sensitive adhesive layer are determined by the composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer (for example, the type of base polymer (polarity, Tg, softness), molecular weight), and the crosslinked structure (for example, It can be controlled by adjusting the type of cross-linking agent, the distance between cross-linking points (molecular weight between cross-linking points), the cross-linking density, and the like. More specifically, the type and combination of the monomer components of the base polymer, the polymerization conditions of the base polymer, the type and the amount of the cross-linking agent used, and the like can be appropriately set.

The thickness of the pressure-sensitive adhesive layer is preferably 2 μm to 55 μm, more preferably 2 μm to 30 μm, further preferably 2 μm to 20 μm, and particularly preferably 5 μm to 15 μm. When the thickness of the pressure-sensitive adhesive layer is within such a range, the adhesive chipping of the deformed portion can be remarkably suppressed by the synergistic effect with the effect of controlling the creep value.

The pressure-sensitive adhesive layer is typically formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer, a urethane-based polymer, a silicone-based polymer, or a rubber-based polymer as a base polymer. When a (meth) acrylic polymer is used as the base polymer, the pressure-sensitive adhesive layer is formed from, for example, a pressure-sensitive adhesive composition containing the (meth) acrylic polymer (A). The (meth) acrylic polymer (A) contains an alkyl (meth) acrylate as a main component.

C-2. (Meta) 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 the monomer components forming the (meth) acrylic polymer (A) from the viewpoint of improving the adhesiveness of the pressure-sensitive adhesive layer, and the alkyl (meth) acrylate is said. ) It can be arbitrarily set as the remainder of the monomer other than acrylate. In addition, (meth) acrylate means acrylate and / or methacrylate.

Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer (A) include linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group and a decyl group. , Isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like. Alkyl (meth) acrylates can be used alone or in combination. The average carbon number of the alkyl group is preferably 3 to 10.

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

The carboxyl group-containing monomer (a1) is a compound containing a carboxyl group in its structure and containing 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, and crotonic acid. Among these, acrylic acid is preferable from the viewpoint of improving copolymerizability, price, and adhesive properties of the pressure-sensitive adhesive layer.

When a carboxyl group-containing monomer (a1) is used as the monomer component, the content of the carboxyl group-containing monomer (a1) is usually 0.01% by weight in all the monomer components forming the (meth) acrylic polymer (A). It is 10% by weight or less.

The hydroxyl group-containing monomer (a2) is a compound containing a hydroxyl group in its structure and containing a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl ( Examples thereof include hydroxyalkyl (meth) acrylates such as 10-hydroxydecyl (meth) acrylate and 12-hydroxylauryl (meth) acrylate; (4-hydroxymethylcyclohexyl) -methylacrylate and the like. Among these, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable, and 4-hydroxybutyl (meth) acrylate is more preferable, from the viewpoint of improving the durability of the pressure-sensitive adhesive layer.

When a hydroxyl group-containing monomer (a2) is used as the monomer component, the content of the hydroxyl group-containing monomer (a2) is usually 0.01% by weight in all the monomer components forming the (meth) acrylic polymer (A). It is 10% by weight or less.

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

The proportion of the (meth) acrylic polymer (A) containing 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. The content is the total content when two or more types of monomers (a3) are used in combination.

Examples of the monomer (a3) include 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.), linear alkyl (meth) acrylates such as n-stearyl acrylate (Tg: 30 ° C.), and n-stearyl methacrylate (Tg: 38 ° C.); t-butyl acrylate (Tg: 43 ° C.), t- Branched chain alkyl (meth) acrylates such as butyl methacrylate (Tg: 48 ° C.), i-propyl methacrylate (Tg: 81 ° C.), and i-butyl methacrylate (Tg: 48 ° C.); cyclohexyl acrylate (Tg: 19 ° C.), Cyclic alkyl (meth) acrylates such as cyclohexyl methacrylate (Tg: 65 ° C.), isobornyl acrylate (Tg: 94 ° C.), and isobornyl methacrylate (Tg: 180 ° C.); acrylic acid (Tg: 106 ° C.) and the like. Can be mentioned. These can be used alone or in combination.

The copolymerization monomer becomes a reaction point with the cross-linking agent when the pressure-sensitive adhesive composition contains a cross-linking agent described later. Since the carboxyl group-containing monomer and the hydroxyl group-containing monomer are highly reactive with the intermolecular cross-linking agent, they are preferably used for improving the cohesiveness and heat resistance of the obtained pressure-sensitive adhesive layer. Further, the carboxyl group-containing monomer is preferable from the viewpoint of achieving both durability and reworkability, and the hydroxyl group-containing monomer is preferable from the viewpoint of improving the reworkability.

Other copolymerization monomer (a4) may be further used as the monomer component. The other copolymerizable monomer (a4) has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. By using the other copolymerization monomer (a4), the adhesiveness and heat resistance of the pressure-sensitive adhesive layer can be improved. The other copolymerization monomer (a4) can be used alone or in combination.

By using an amino group-containing monomer and an amide group-containing monomer as the other copolymerization monomer (a4), the adhesion of the pressure-sensitive adhesive layer can be improved. The amino group-containing monomer is, for example, N, N-dimethylaminoethyl (meth) acrylate or N, N-dimethylaminopropyl (meth) acrylate. The amide group-containing monomer includes, for example, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, N-methyl (meth) acrylamide, and N-butyl ( Meta) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) ) Acrylamides such as acrylamide and mercaptoethyl (meth) acrylamide; N-acrylloyl heterocyclic monomers such as N- (meth) acryloylmorpholin, N- (meth) acryloylpiperidin and N- (meth) acryloylpyrrolidin. It is an N-vinyl group-containing lactam-based monomer such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

The other copolymerization monomer (a4) may be a polyfunctional monomer. By using the polyfunctional monomer, the gel fraction of the pressure-sensitive adhesive layer can be adjusted and the cohesive force can be controlled. Polyfunctional monomers include, for example, 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, trimethyl propantri (meth) Polyfunctional acrylates such as acrylates, tetramethylolmethanetri (meth) acrylates, allyl (meth) acrylates, vinyl (meth) acrylates, epoxy acrylates, polyester acrylates, urethane acrylates; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate or dipentaerythritol hexa (meth) acrylate.

Other copolymerization monomers (a4) include, for example, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and (meth). (Meta) acrylic acid alkoxyalkyl esters such as 3-methoxypropyl acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate; 2-( Cyclic polymerizable monomer such as methyl allyloxymethyl) acrylate; epoxy group-containing monomer such as (meth) glycidyl acrylate, methyl glycidyl (meth) acrylate; sulfonic acid group-containing monomer such as sodium vinyl sulfonate; phosphoric acid Group-containing monomer; (meth) acrylate having an alicyclic hydrocarbon group such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate; phenyl (meth) acrylate, (meth). ) (Meta) acrylic acid esters having aromatic hydrocarbon groups such as phenoxyethyl acrylate and benzyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene Olefins or dienes such as ethylene, propylene, butadiene, isoprene and isobutylene; vinyl ethers such as vinylalkyl ethers; vinyl chloride can be used.

The content of the other copolymerization monomer (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. It is preferably 5% by mass or less.

C-3. Method for Producing (Meta) Acrylic Polymer (A) The (Meta) Acrylic Polymer (A) can be produced by any suitable method. Specific examples of the production method include various radical polymerizations such as radiation polymerization such as electron beam and UV, solution polymerization, bulk polymerization, and emulsion polymerization. The obtained (meth) acrylic polymer (A) may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

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

The polymerization initiator, chain transfer agent, emulsifier, etc. used for 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 the polymerization initiator and the 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. Can be done.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, and 2,2'-azobis [2- (5-methyl-2). -Imidazoline-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2 Azo-based initiators such as'-azobis [N- (2-carboxyethyl) -2-methylpropion amidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), persulfates such as potassium persulfate and ammonium persulfate. , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylper Oxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di (4) Peroxides such as -methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butylhydroperoxide, hydrogen peroxide, etc. Examples thereof include an initiator, a combination of persulfate and sodium hydrogen sulfite, and a redox-based initiator in which a peroxide and a reducing agent such as a combination of peroxide and sodium ascorbate are combined.

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

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglucolate, and 2,3-dimercapto-1-propanol. 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 with respect to 100 parts by weight of the monomer component.

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

Examples of the reactive emulsifier include an emulsifier into which a radically polymerizable functional group such as a propenyl group or an allyl ether group has been 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 Risoap SE10N (manufactured by ADEKA Corporation). ). Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it has good water resistance and is preferable. The amount of the emulsifier used is preferably 0.3 parts by weight to 5 parts by weight, and more preferably 0.5 parts by weight to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. When the amount of the emulsifier used is in such a range, the polymerization stability and the mechanical stability of the obtained pressure-sensitive adhesive layer are excellent.

When the (meth) acrylic polymer (A) is produced by radiation polymerization, it can be produced by polymerizing the monomer component by irradiating the monomer component with radiation such as electron beam or UV. When the radiation polymerization is carried out by UV polymerization, a photopolymerization initiator can be contained in the monomer component. Thereby, the polymerization time can be shortened. When the radiation polymerization is carried out by an electron beam, it is not particularly necessary to include a photopolymerization initiator in the monomer component.

Any suitable photopolymerization initiator can be used as the photopolymerization disclosure agent. Specific examples thereof include benzoin ether-based, acetophenone-based, α-ketol-based, photoactive oxime-based, benzoin-based, benzyl-based, benzophenone-based, ketal-based, and thioxanthone-based photopolymerization initiators. The amount of the photopolymerization initiator used is preferably 0.02 parts by weight to 1.5 parts by weight, more preferably 0.1 parts by weight to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components. .. The photopolymerization disclosure agent can be used alone or in combination.

The weight average molecular weight Mw of the (meth) acrylic polymer (A) is, for example, 200,000 to 3 million, preferably 1 million to 2.5 million, and more preferably 1.2 million to 2.5 million, as described above. When the weight average molecular weight Mw is in such a range, a pressure-sensitive adhesive layer having excellent durability (particularly heat resistance) can be obtained. If the weight average molecular weight Mw exceeds 3 million, an increase in viscosity and / or gelation during polymer polymerization may occur.

The polydispersity (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the (meth) acrylic polymer (A) is preferably 5.0 or less, more preferably 1.05 to 5.0. More preferably, it is 1.05 to 4.0. When the degree of polydispersity (Mw / Mn) is large (for example, exceeding 5.0), there are many low molecular weight polymers, and even if the pressure-sensitive adhesive layer is formed so that the creep values are the same, uncrosslinked polymers or As the amount of oligomer (sol) increases, the toughness of the pressure-sensitive adhesive layer decreases (becomes fragile), and adhesive chipping during deformed processing and peeling in a high-temperature and high-humidity environment may occur. The degree of polydispersity (Mw / Mn) is measured by GPC (gel permeation chromatography) in the same manner as the weight average molecular weight, and is obtained from a value calculated by polystyrene conversion.

C-4. Reactive functional group-containing silane coupling agent The pressure-sensitive adhesive composition can contain a reactive functional group-containing silane coupling agent. In the reactive functional group-containing silane coupling agent, the reactive functional group is typically a functional group other than the 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 and a (meth) acrylic. Examples include groups, heterocyclic groups, and combinations thereof. Reactive functional group-containing silane coupling agents can be used alone or in combination.

Examples of the reactive functional group-containing silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3, 4-Epoxycyclohexyl) Epoxy group-containing silane coupling agent such as ethyltrimethoxysilane; mercapto group-containing silane coupling agent such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; 3-aminopropyltrimethoxy Silane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane Amino group-containing silane coupling agents such as 3-isocyanuspropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanoxide propyltriethoxysilane; vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; p-styryltri Styryl group-containing silane coupling agents such as methoxysilane; (meth) acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane can be mentioned. Among these, an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent are preferable. As an epoxy group-containing silane coupling agent, for example, "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd. is commercially available.

As the reactive functional group-containing silane coupling agent, one having a plurality of alkoxysilyl groups in the molecule (oligomer-type silane coupling agent) 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 "; Examples thereof include mercapto group-containing oligomer-type silane coupling agents" X-41-1818 "," X-41-1810 ", and" X-41-1805 ". Since the oligomer-type silane coupling agent is hard to volatilize and has a plurality of alkoxysilyl groups, it can be effective in improving durability.

When the reactive functional group-containing silane coupling agent is blended in the pressure-sensitive adhesive composition, the blending amount of the reactive functional group-containing silane coupling agent is usually 100 parts by weight of the (meth) acrylic polymer (A). 0.001 part by weight or more and 5 parts by weight or less.

C-5. Cross-linking agent The pressure-sensitive adhesive composition can contain a cross-linking agent. As the cross-linking agent, an organic cross-linking agent, a polyfunctional metal chelate, or the like can be used. Examples of the organic cross-linking agent include isocyanate-based cross-linking agents, peroxide-based cross-linking agents, epoxy-based cross-linking agents, and imine-based cross-linking agents. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated 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 and the like. Can be mentioned. Examples of the atom in the organic compound having a covalent bond or a coordination 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, and a ketone compound. Further, when the pressure-sensitive adhesive composition is a radiation-curable type, a polyfunctional monomer can be used as a cross-linking 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, and (. Poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethyl propantri (meth) ) Polyfunctional acrylates such as acrylates, tetramethylol methanetri (meth) acrylates, allyl (meth) acrylates, vinyl (meth) acrylates, epoxy acrylates, polyester acrylates, urethane acrylates; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate or dipentaerythritol hexa (meth) acrylate. Crosslinkers can be used alone or in combination.

When the pressure-sensitive adhesive composition is a solvent type, the cross-linking agent is preferably an isocyanate-based cross-linking agent and / or a peroxide-based cross-linking agent, and particularly preferably an isocyanate-based cross-linking agent from the viewpoint of reducing adhesive chipping during processing. From the viewpoint of suppressing peeling in a high temperature and high humidity environment, it is more preferable to use an isocyanate-based cross-linking agent and a peroxide-based cross-linking agent in combination.

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

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethyl. Hexamethylene diisocyanate can be mentioned.

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, and hydrogenated tolylene diisocyanate. Examples include added tetramethylxylylene diisocyanate.

Examples of the aromatic diisocyanate include phenylenediisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and 4,4. Examples thereof include'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalenediocyanate and xylylene diisocyanate.

As another example of the isocyanate-based cross-linking agent, the above-mentioned multimer of diisocyanate (dimeric, trimeric, pentameric, etc.), urethane modified product reacted with polyhydric alcohol such as trimethylolpropane, urea modified product, etc. , Biuret modified product, alphanate modified product, isocyanurate modified product, carbodiimide modified product.

Examples of commercially available isocyanate-based cross-linking agents include the trade names "Millionate MT", "Millionate MTL", "Millionate MR-200", "Millionate MR-400", "Coronate L", and "Millionate M" manufactured by Tosoh Corporation. "Coronate HL", "Coronate HX", trade names "Takenate D-110N", "Takenate D-120N", "Takenate D-140N", "Takenate D-160N", "Takenate D-" manufactured by Mitsui Chemicals, Inc. 165N ”,“ Takenate D-170HN ”,“ Takenate D-178N ”,“ Takenate 500 ”,“ Takenate 600 ”.

As the isocyanate-based cross-linking agent, aromatic polyisocyanate and its modified aromatic polyisocyanate compound, aliphatic polyisocyanate and its modified aliphatic polyisocyanate compound are preferable. Aromatic polyisocyanate compounds are preferably used because they have a good balance between the cross-linking rate and the pot life. As the aromatic polyisocyanate compound, tolylene diisocyanate and a modified product thereof are particularly preferable.

As the peroxide-based cross-linking agent, any suitable as long as radically active species are generated by heating or light irradiation to promote cross-linking of the base polymer ((meth) acrylic polymer (A)) of the pressure-sensitive adhesive composition. Peroxide-based cross-linking agent can be used. A peroxide having a 1-minute half-life temperature of 80 ° C. to 160 ° C. is preferable, and a peroxide having a 1-minute half-life temperature of 90 ° C. to 140 ° C. is more preferable. Such peroxides are excellent in workability and stability.

Examples of the peroxide as described above include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.) and di (4-t-butylcyclohexyl) peroxydicarbonate (1). Minute half-life temperature: 92.1 ° C., di-sec-butylperoxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butylperoxyneodecanoate (1 minute half-life temperature: 103) .5 ° C.), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C.), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C.), dilauroyl peroxide (1 minute half-life temperature: 110.3 ° C.) 1 minute half-life temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130. 0 ° C.), t-Butylperoxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) Can be mentioned. Of these, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide are preferable because of their excellent cross-linking reaction efficiency.

The half-life of peroxide is an index showing the decomposition rate of peroxide, and means the time until the residual amount of peroxide is halved. The decomposition temperature for obtaining a half-life at an arbitrary temperature and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc. For example, "Organic Peroxide Catalog No. 9" of Nippon Oil & Fats Co., Ltd. Edition (May 2003) ”and so on.

When a cross-linking agent is blended in the pressure-sensitive adhesive composition, the blending amount of the cross-linking agent is usually 0.01 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer (A).

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

When a peroxide is blended in the pressure-sensitive adhesive composition, the blending amount of the peroxide is usually 0.01 parts by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer. Within such a range, it is easy to adjust workability, cross-linking stability, and the like.

C-6. Other Ingredients The pressure-sensitive adhesive composition may contain a (meth) acrylic oligomer. The (meth) acrylic oligomer can be obtained by polymerizing the monomer components described in item C-2 with respect to the (meth) acrylic polymer alone or by copolymerizing two or more kinds. The type, number, combination, and polymerization molar ratio of the monomer components can be appropriately set according to the purpose, desired properties, and the like. The weight average molecular weight Mw of the (meth) acrylic oligomer is preferably 1000 to 8000, more preferably 2000 to 7000, and further preferably 3000 to 6000. When the (meth) acrylic oligomer is blended in the pressure-sensitive 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.

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, and among them, (perfluoroalkylsulfonyl) imide lithium salt is preferable, and bis (trifluoromethanesulfonylimide) lithium is preferable. Is more preferable. 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, based on 100 parts by weight of the (meth) acrylic polymer (A). It is particularly preferable to be parts by weight or less.

The pressure-sensitive adhesive composition may contain an additive. Specific examples of additives include powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, and light. Stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates, foils and the like. Further, a redox system to which a reducing agent is added may be adopted within a controllable range. The type, number, combination, content, etc. of additives 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 further preferably 1 part by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer (A). is there.

D. Image Display Device The optical film with an adhesive layer according to the embodiment of the present invention can be suitably applied to an image display device as described above. Therefore, an image display device including an optical film with an 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 an adhesive layer attached to the image display cell via an 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. An organic EL display device is preferable. This is because the effect of the optical film with an adhesive layer is remarkable.

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. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

(1) Gel fraction The pressure-sensitive adhesives used in Examples and Comparative Examples were crosslinked, immersed in ethyl acetate for 6 days, and then dried. The gel fraction (%) was calculated from the following formula.
Gel fraction (%) = (dry weight after immersion / dry weight before immersion) x 100
(2) Degree of swelling The pressure-sensitive adhesives used in Examples and Comparative Examples were crosslinked and immersed in ethyl acetate for 6 days. The degree of swelling (%) was calculated from the following formula.
Swelling degree (times) = weight after immersion / dry weight after immersion (3) Separator peeling force The optical film with adhesive layer (before deforming) used in Examples and Comparative Examples was cut into a size of 50 mm × 150 mm. It was used as a measurement sample. Using a tensile tester (Autograph SHIMAZU AG-1 50N), the separator was peeled from the measurement sample at a tensile angle = 180 ° and a tensile speed = 300 mm / min, and the peeling force of the separator was measured.
(4) Creep value The optical film with an adhesive layer obtained in Examples and Comparative Examples was cut into a size of 10 mm × 30 mm and used as a test sample. The upper end portion 10 mm × 10 mm of the test sample was attached to a SUS plate via an adhesive layer, and autoclaved under the conditions of 50 ° C. and 5 atm for 15 minutes. A precision hot plate installed so that the heating surface is in the vertical direction is heated to 85 ° C., and the SUS plate to which the optical film with the adhesive layer is attached is the surface of the hot plate to which the adhesive layer is not attached. It was installed so as to be in contact with the heating surface. After heating the SUS plate at 85 ° C. for 5 minutes, a load of 500 gf was vertically downwardly applied to the lower end portion of the polarizing film with the pressure-sensitive adhesive layer. The amount of displacement between the optical film with the adhesive layer and the SUS plate after 1 second and 3600 seconds after applying the load was measured and used as Cr ₁ and Cr ₃₆₀₀ , respectively. The creep value was ΔCr obtained from _{Cr 1} and Cr _{3600 by the following formula.}
ΔCr = Cr _3600- Cr ₁
(5) Amount of adhesive chipping The state of the cross section of the pressure-sensitive adhesive layer in the deformed portion of the optical film with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was observed with an optical microscope, and the pressure-sensitive adhesive from the outer edge to the inside in the plane direction. The length of the portion where the layer was maximally missing was measured, and the length was defined as the amount of adhesive chipping (μm).
(6) Durability The optical film with an adhesive layer obtained in Examples and Comparative Examples was cut into a size of 300 mm × 220 mm and used as a test sample. At this time, the polarizing element was cut out so that the absorption axis was in the long side direction. This test sample was attached to a non-alkali glass (manufactured by Corning Inc., trade name "EG-XG") having a thickness of 350 mm × 250 mm × 0.7 mm with a laminator. Then, it was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to bring the pressure-sensitive adhesive layer into close contact with the glass. The test sample thus treated was treated in an atmosphere of 60 ° C./95% RH for 500 hours. The appearance of the test sample after the treatment was visually evaluated according to the following criteria.
◯: No change in appearance such as foaming and peeling.
Δ: There is slight peeling or foaming at the end, but there is no problem in practical use.
×: There is a remarkable peeling at the end, and there is a problem in practical use.

<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 introduction tube, and a cooler. Further, with respect to 100 parts of this monomer mixture, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, and nitrogen gas was introduced with gentle stirring to introduce nitrogen. After the substitution, the liquid temperature in the flask was maintained at around 55 ° C. and the polymerization reaction was carried out for 8 hours to prepare a solution of the acrylic polymer A1 having a weight average molecular weight (Mw) of 1.8 million and Mw / Mn = 4.8. ..

<Production Example 2: Preparation of acrylic polymer A2>
Mw 2.3 million, Mw / Mn = 3.9 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. A solution of acrylic polymer A2 was prepared.

<Production Example 3: Preparation of acrylic polymer (monomer partial polymer) A3>
65 parts of 2-ethylhexyl acrylate, 15 parts of N-vinylpyrrolidone and 2 in a four-necked flask equipped with a thermometer, a nitrogen gas inlet tube, a cooler, and a spindle connected to a B-type viscometer (rotary viscometer). A monomer mixture containing 20 parts of -hydroxyethyl acrylate was charged. Further, 0.05 parts each of Ominirad 651 and Omnirad 184, which are photopolymerization initiators, was charged to 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 rays were irradiated until the viscosity of the polymerization system measured by the viscometer reached about 15 Pa · s to proceed with photopolymerization. Acrylic polymer A3 containing a partial polymer of the monomer group was obtained. A BH type viscometer manufactured by Toki Sangyo was used, and the rotation speed of the spindle (rotor No. 5) was 10 rpm. The temperature of the liquid in the flask was maintained at 30 ° C.

<Production Example 4: Preparation of acrylic polymer A4>
Mw 2.7 million, as in Production Example 1, except that a monomer mixture containing 91 parts of butyl acrylate, 6 parts of N-acryloyl morpholine, 0.3 parts of 4-hydroxybutyl acrylate and 2.7 parts of acrylic acid was used. A solution of acrylic polymer A4 with Mw / Mn = 3.8 was prepared.

<Production Example 5: Preparation of acrylic polymer A5>
A solution of an acrylic polymer A5 having a 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.

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

<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 are mixed at 70 ° C. under a nitrogen atmosphere. The mixture was stirred for 1 hour. Next, 0.2 part of AIBN was added as a thermal polymerization initiator, and the mixture was reacted at 70 ° C. for 2 hours, then heated to 80 ° C. and reacted for 2 hours. Then, the reaction solution was heated to 130 ° C., and toluene, the chain transfer agent and the unreacted monomer were dried and removed to obtain a (meth) acrylic oligomer B2.

<Manufacturing Example 8: Fabrication of Polarizing Plate>
(Preparation of TAC film with HC)
A solution in a resin solution (manufactured by DIC Corporation, trade name: Unidic 17-806, solid content concentration: 80%) in which an ultraviolet curable resin monomer or oligomer containing urethane acrylate as a main component is dissolved in butyl acetate. For every 100 parts of the solid content, 5 parts of a photopolymerization initiator (manufactured by BASF Corporation, trade name: IRGACURE907) and 0.1 part of a leveling agent (manufactured by DIC Corporation, trade name: GRANDIC PC4100) are added. did. A hard coat layer forming material was prepared by adding cyclopentanone and propylene glycol monomethyl ether to the solution at a ratio of 45:55 so that the solid content concentration in the solution was 36%. 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 hard coat layer after curing was 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 with} a high-pressure mercury lamp to cure the coating film to form a hard coat layer to prepare a TAC film with HC. The obtained TAC film with HC was saponified.

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

<Example 1>
(Preparation of adhesive composition)
With respect to 100 parts of the solid content of the solution of the acrylic polymer A1 obtained in Production Example 1, 30 parts of the acrylic oligomer B1 (solid content) obtained in Production Example 4 and an isocyanate cross-linking agent (manufactured by Toso Co., Ltd., trade name) "Takenate D110N", trimethylolpropane / xylylene diisocyanate adduct) 0.02 part, peroxide cross-linking agent (manufactured by Nippon Oil & Fats Co., Ltd., trade name "Niper BMT") 1 part, silane coupling agent (Shinetsu Chemical Industry Co., Ltd.) A solution of the acrylic pressure-sensitive adhesive composition was prepared by blending 0.2 parts of the product, trade name "KBM-403").

(Preparation of polarizing plate with adhesive layer)
Adhesion of the solution of the acrylic pressure-sensitive adhesive composition obtained above 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 after drying. It was applied so that the thickness of the agent 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 pressure-sensitive adhesive layer formed on the separator film was bonded to the TAC film (KC4CT) side of the polarizing plate produced in Production Example 8 to prepare an optical film with a pressure-sensitive adhesive layer (polarizing plate with a pressure-sensitive adhesive layer). .. The obtained optical film with an adhesive layer was deformed. At that time, a laminated body in which a surface protective film (manufactured by Nitto Denko, trade name "PPF-100T") was laminated on the TAC film side with HC of the obtained optical film with an adhesive layer was used as a workpiece to be deformed. .. More specifically, a bundle of laminated bodies stacked to a height of 10 mm is fixed with a clamp, and a through hole is made from the surface protective film side using an end mill having a blade diameter of 2.0 mm, and the diameter of the hole is increased. It was cut to 2.5 mm (processed into a shape corresponding to the center of the lower part of FIG. 2). The rotation speed of the blade during cutting was 2500 rpm, and the feed rate was 50 mm / min. The pressure-sensitive adhesive layer used for producing the optical film with the pressure-sensitive adhesive layer was subjected to the evaluations of (1) and (2) above, and the optical film with the pressure-sensitive adhesive layer before the deformation processing was subjected to the evaluation of (3) above. The polarizing plate with an adhesive layer was subjected to the evaluations (4) to (6) above. The results are shown in Table 1.

<Examples 2 to 6 and Examples 9 to 13>
An optical film with a pressure-sensitive adhesive layer processed in the same manner as in Example 1 was produced in the same manner as in Example 1 except that the composition of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer and the thickness of the pressure-sensitive adhesive layer were changed as shown in Table 1. did. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Example 7>
An optical film with an adhesive layer that had been deformed was produced in the same manner as in Example 6 except that the separator was reattached once before the deforming. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Example 8>
An optical film with an adhesive layer that had been deformed was produced in the same manner as in Example 6 except that the separator was reattached twice. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Examples 14 and 15>
(Preparation of adhesive composition)
10 parts of the (meth) acrylic oligomer B2 obtained in Production Example 7 was added to 100 parts of the acrylic polymer (monomer partial polymer) A3 obtained in Production Example 3, and a polyfunctional monomer (monomer partial polymer) as a cross-linking agent. Shin-Nakamura Chemical Co., Ltd., trade name "A-HD-N", 1,6-hexanediol diacrylate) 0.1 part, silane coupling agent (Shinetsu Chemical Industry Co., Ltd., trade name "KBM-403") 0 . Two parts were mixed to prepare a mixture. Next, after applying the mixture to the surface of a PET film (thickness 38 μm) which is a base film (separator), further the PET film is placed on the coating film of the mixture, and a pair of PET films is used. The coating film was sandwiched. Next, the coating film was cured by irradiating with ultraviolet rays under irradiation conditions of an illuminance of 4 mW / cm ² and a light intensity of 1200 mJ / cm ² , to form adhesive layers (25 μm and 50 μm) having the thickness shown in Table 1. After the pressure-sensitive adhesive layer was formed, the further PET film was peeled off to expose the pressure-sensitive adhesive layer, and an optical film with a pressure-sensitive adhesive layer processed in the same manner as in Example 1 was produced. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Examples 16 to 19 and Comparative Example 1>
An optical film with a pressure-sensitive adhesive layer processed in the same manner as in Example 1 was produced in the same manner as in Example 1 except that the composition of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer and the thickness of the pressure-sensitive adhesive layer were changed as shown in Table 1. did. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Example 20>
An optical film with an adhesive layer that had been deformed was produced in the same manner as in Example 19 except that the separator was reattached once. The pressure-sensitive adhesive layer used for producing the optical film with a pressure-sensitive adhesive layer, the optical film with a pressure-sensitive adhesive layer having a separator, and the deformed polarizing plate with a pressure-sensitive adhesive layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

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

(Preparation of retardation layer A)
10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, product name "Pariocolor LC242", represented by the following formula) and a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name " 3 g of Irgacure 907 ”) was dissolved in 40 g of toluene to prepare a liquid crystal composition (coating liquid).

The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an orientation treatment. The conditions of the orientation treatment were 1 for the number of rubbing rolls (number of rubbing rolls), 76.89 mm for the rubbing roll radius r, 1500 rpm for the rubbing roll rotation speed nr, and 83 mm / sec for the film transport speed v.

The direction of the orientation treatment was set to be −75 ° when viewed from the visual side with respect to the direction of the absorption axis of the polarizer when the polarizing plate was attached. The coating liquid was applied to the alignment-treated surface with a bar coater, and the liquid crystal compound was oriented by heating and drying at 90 ° C. for 2 minutes. ^{The liquid crystal layer thus formed was irradiated with light of 1 mJ / cm 2} using a metal halide lamp, and the liquid crystal layer was cured to form 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.

(Preparation of retardation layer B)
The surface of a polyethylene terephthalate (PET) film (thickness 38 μm) was rubbed with a rubbing cloth and subjected to an orientation treatment. The direction of the orientation treatment was set to be -15 ° when viewed from the visual side with respect to the direction of the absorption axis of the polarizer when the polarizing plate was attached. A liquid crystal coating solution similar to the above was applied to the alignment-treated surface, and the liquid crystal was oriented and cured in the same manner as described 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.

(Manufacturing of polarizing plate with retardation layer)
The TAC film surface of the above polarizing plate and the retardation layer A were bonded together via 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 same adhesive (thickness 5 μm) as in Example 16 was applied to the retardation layer A and the retardation layer B so that the angle between the absorption axis of the polarizing plate and the slow axis of the retardation layer B was 15 °. A polarizing plate with a retardation layer was obtained by laminating them together. Further, the same pressure-sensitive adhesive layers as in Examples 1 to 20 and Comparative Example 1 were formed on the outside of the retardation layer B, respectively. The obtained polarizing plate with a retardation layer was deformed in the same manner as in Example 1 and subjected to the same evaluation as in Example 1. As a result, even in the polarizing plate with a retardation layer, those using the pressure-sensitive adhesive layer corresponding to Examples 1 to 20 have good adhesive chipping and durability, and the pressure-sensitive adhesive layer corresponding to Comparative Example 1 It was confirmed that the one using the above had a large amount of adhesive chipping.

The abbreviations in Table 1 are as follows. The blending amount of each component in Table 1 is the number of copies with respect to 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-Acryloyl morpholine D110N: Trimethylol propane / xylylene diisocyanate adduct (manufactured by Toso Co., Ltd., trade name "Takenate D110N")
C / L: Trimethylolpropane / Tolylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L")
Peroxide: Peroxide cross-linking agent (manufactured by NOF CORPORATION, trade name "Nipper BMT")
A-HD-N: 1,6-hexainediol diacrylate (manufactured by Shin Nakamura Chemical Industry 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 "Irganox 1010")

<Evaluation>
As is clear from Table 1, according to the examples of the present invention, an optical film with an adhesive layer in which adhesive chipping is remarkably suppressed in the deformed portion and peeling is suppressed in a high temperature and high humidity environment is actually obtained. I was able to get it. In Comparative Example 1 in which the creep value of the pressure-sensitive adhesive layer was large, the amount of adhesive chipping was large. Further, in the optical film with an adhesive layer having a separator, when the peeling force of the separator was small, the amount of adhesive chipping was large (for example, comparison between Examples 6 and 8 and comparison with Examples 19 and 20).

The optical film with an adhesive layer of the present invention is suitably used for an image display device, and particularly for an image display device having a deformed portion represented by an automobile instrument panel, a smartphone, a tablet PC or a smart watch. It can be preferably used.

Claims

An optical film with an adhesive layer having an optical film and an adhesive layer on one surface of the optical film.
The optical film with an adhesive layer has a shape other than a rectangle and has a deformed shape other than a rectangle.
The creep value of the pressure-sensitive adhesive layer at 85 ° C. is 500 μm or less.
Optical film with adhesive layer.
The optical film with an adhesive layer according to claim 1, wherein the creep value is 5 μm or more.
The optical film with an adhesive layer according to claim 1 or 2, wherein the thickness of the adhesive layer is 2 μm to 20 μm.
A separator is temporarily attached to the surface of the pressure-sensitive adhesive layer opposite to the optical film so that it can be peeled off.
The optical film with an adhesive layer according to any one of claims 1 to 3, wherein the separator has a peeling force of 0.04 N / 50 mm to 0.5 N / 50 mm.
The optical film with an adhesive layer according to any one of claims 1 to 4, wherein the optical film contains a polarizer.
The optical film with an adhesive layer according to claim 5, wherein the optical film further includes a retardation layer.
An image display device including the optical film with an adhesive layer according to any one of claims 1 to 6.