KR20180013768A - Optical laminate - Google Patents

Abstract

An object of the present invention is to provide an optical laminate which is hardly yellowish with time and is excellent in yellowing suppression even when exposed under a high temperature environment.
[MEANS FOR SOLVING PROBLEMS] An optical laminate comprising a first pressure-sensitive adhesive layer, a polarizing plate and a second pressure-sensitive adhesive layer in this order,
Wherein the polarizer comprises a polarizer having a thickness of 23 m or less, the polarizer is a polyvinyl alcohol-based resin film containing a dichroic dye,
Wherein the total thickness of the pressure-sensitive adhesive layers included in the optical laminate is T1 and the thickness of the polarizer is T2, T2 / T1 is 0.6 or less.

Description

Optical laminate {OPTICAL LAMINATE}

The present invention relates to an optical laminate and an image display apparatus including the optical laminate. More particularly, the present invention relates to an optical laminate used by bonding a transparent plate and an image display cell through a pressure-sensitive adhesive layer, and an image display apparatus including the optical laminate.

Conventionally, an optical laminate such as a polarizing plate or an elliptically polarizing plate is bonded to an image display cell such as a liquid crystal cell or an organic EL element through a pressure-sensitive adhesive layer between a transparent plate such as a front plate or a touch panel, And is used in various image display devices such as organic EL display devices. In recent years, such an image display apparatus has been widely used, for example, as a vehicle-mounted image display apparatus such as a car navigation apparatus or a back monitor in addition to a mobile apparatus such as a cellular phone or a tablet terminal. Accordingly, the optical laminate is required to have high durability under an environment (for example, a high temperature environment) that is harsher than what has been conventionally required, and a polarizing plate for the purpose of securing such durability has been proposed (Patent Document 1).

Japanese Patent Application Laid-Open No. 2014-102353

An image display apparatus constituted by bonding an optical laminate using a polyvinyl alcohol based resin film containing a dichroic dye as a polarizer to an image display cell and a transparent plate through a pressure sensitive adhesive layer, , Polyenes of polyvinyl alcohol proceed, so that there may arise a problem that the optical laminate is yellowed. Such yellowing becomes an apparent defect of the optical laminate, and also the optical properties of the optical laminate are defective due to the progress of yellowing. In particular, the progress of the yellowing tendency becomes more conspicuous under a severe temperature condition exceeding 95 占 폚 (for example, at 105 占 폚, etc.), and an optical laminate having a high suppressing effect against yellowing under such a high temperature environment is required.

Accordingly, it is an object of the present invention to provide an optical laminate which is hardly yellowish with time and is excellent in yellowing suppression even when exposed under a high temperature environment.

Means for Solving the Problems The present inventors have intensively studied in order to solve the above problems, and have completed the present invention.

That is, the present invention provides the following preferred embodiments.

[1] An optical laminate comprising a first pressure-sensitive adhesive layer, a polarizing plate and a second pressure-sensitive adhesive layer in this order,

Wherein the polarizer comprises a polarizer having a thickness of 23 m or less, the polarizer is a polyvinyl alcohol-based resin film containing a dichroic dye,

Wherein the total thickness of the pressure-sensitive adhesive layers included in the optical laminate is T1 and the thickness of the polarizer is T2, T2 / T1 is 0.6 or less.

[2] The optical laminate according to the above [1], wherein the polarizer has an absorbance A ₇₀₀ at a wavelength of 700 nm of 5.5 or less.

[3] The optical laminate according to the above [1] or [2], which is used by bonding between a transparent plate and an image display cell through the pressure-sensitive adhesive layer.

[4] The optical laminate according to any one of [1] to [3], wherein the polarizing plate comprises a protective film having a water vapor transmission rate of 200 g / m 2 · 24 hours or more laminated on at least one surface of the polarizer.

[5] An image display apparatus comprising the optical laminate according to any one of [1] to [4].

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an optical laminate excellent in yellowing suppression effect when yellowing is not easily caused with time and is exposed under a high temperature environment.

1 is a cross-sectional view showing a configuration of an optical laminate as one embodiment of the present invention.
2 is a cross-sectional view showing a configuration of an image display apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, but can be modified in various ways without departing from the spirit of the present invention.

The optical laminate (also referred to as " the optical laminate of the present invention ") according to an embodiment of the present invention comprises a first pressure-sensitive adhesive layer, a polarizing plate and a second pressure-sensitive adhesive layer in this order. 1, the optical laminate of the present invention has a structure in which a first pressure sensitive adhesive layer 2 is laminated on one surface of a polarizing plate 10, And the second pressure sensitive adhesive layer 2 'is laminated on the surface of the polarizing plate 10 opposite to the first pressure sensitive adhesive layer 2. In the optical laminate of the present invention, in order to protect the pressure-sensitive adhesive layer, on the surface opposite to the polarizing plate 10 of the first pressure-sensitive adhesive layer 2 and the second pressure-sensitive adhesive layer 2 ' May be adhered.

By peeling the protective sheet 5 and bonding the first pressure sensitive adhesive layer 2 to the image display cell 7 and the second pressure sensitive adhesive layer 2 'to the transparent plate 6, An image display apparatus (also referred to as " image display apparatus of the present invention ") which is one embodiment of the present invention is constituted. In Fig. 2, the backlight and the like are omitted.

The polarizing plate 10 constituting the optical laminate of the present invention includes the polarizer 1. [ The polarizing plate 10 may have a structure in which the protective film 3 is provided on at least one surface of the polarizer 1 and the polarizer 1 and the protective film 3 are bonded to each other via the adhesive layer 4 There may be. In one embodiment of the optical laminate of the present invention, the optical laminate of the present invention has the protective film 3 on both sides of the polarizer 1 with the adhesive layer 4 interposed therebetween.

Hereinafter, the constituent members of the optical laminate of the present invention will be described in detail.

≪ Optical laminate &

In the optical laminate of the present invention, when the total thickness of all the pressure-sensitive adhesive layers constituting the optical laminate is T1 and the thickness of the polarizer is T2, the value of T2 / T1 is 0.6 or less, preferably 0.55 or less More preferably 0.50 or less, and particularly preferably 0.45 or less. When the value of T2 / T1 exceeds 0.6, it becomes difficult to suppress the yellowing in the case of being exposed under a high temperature environment (particularly, at a temperature exceeding 95 캜, for example, at a temperature of 105 캜 or higher). The lower limit of T2 / T1 in the optical laminate of the present invention is not particularly limited, but is, for example, 0.001 or more, preferably 0.005 or more, more preferably 0.008 or more, further preferably 0.01 or more. Here, the total thickness T1 of all the pressure-sensitive adhesive layers constituting the optical laminate is the sum of the thicknesses of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, and in some cases, the thicknesses of the other pressure- The other pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer other than the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer that can be contained in the optical laminate, and includes, for example, a pressure-sensitive adhesive layer for bonding an optical film or optical layer described later to a polarizing plate, A pressure-sensitive adhesive layer which can be used for bonding with a film, and the like. The total thickness T1 of all the pressure-sensitive adhesive layers constituting the optical laminate is not more than the thickness of the first pressure-sensitive adhesive layer and the total thickness of the pressure-sensitive adhesive layers constituting the optical laminate, when the optical laminate does not include another pressure- 2 < / RTI >

In the present invention, the thickness T2 of the polarizer is 23 占 퐉 or less, preferably 20 占 퐉 or less, more preferably 18 占 퐉 or less, further preferably 15 占 퐉 or less. When the thickness of the polarizer is not more than the upper limit value, yellowing of the optical laminate over time does not easily occur and an excellent yellowing suppressing effect can be obtained. When the thickness of the polarizer is less than the above upper limit value, the thickness of the pressure-sensitive adhesive layer which is required due to the smaller thickness of the polarizer is also advantageous from the viewpoint of thinning of the optical laminate. The lower limit of the thickness of the polarizer is not particularly limited, but is, for example, 3 m or more.

In the present invention, controlling the ratio of the thickness of the polarizer and the total thickness of the pressure-sensitive adhesive layer to a predetermined range is one of the characteristics for obtaining the yellowing suppressing effect. That is, even if the thickness of the polarizer is the same, for example, when the predetermined ratio is not satisfied in relation to the total thickness of the pressure-sensitive adhesive layer, it is difficult to obtain a sufficient yellowing suppressing effect. Similarly, even when the total thickness of the pressure-sensitive adhesive layer is the same, even when the predetermined ratio is not satisfied in relation to the thickness of the polarizer, it is difficult to sufficiently suppress the yellowing when exposed under a high-temperature environment.

In the optical laminate of the present invention, by setting the ratio of the thickness of the polarizer and the thickness of the polarizer to the total thickness of the pressure-sensitive adhesive layer within the above-mentioned predetermined range, it is possible to easily impart a high yellowing suppression effect to the optical laminate. The yellowing of the optical laminate is caused by the polyenes of the polyvinyl alcohol of the polarizer, and the polyenes tend to be promoted when the water content of the polarizing plate is large. For this reason, for example, a method of controlling the amount of water contained in the polarizing plate for suppressing polyenes can be used, but a drying process for controlling the water content of the polarizing plate is required, and the drying process is performed at a high temperature and / , The optical properties of the polarizing plate may be lowered. In the present invention, since the yellowing can be suppressed by controlling the ratio of the thickness of the polarizer and the thickness of the polarizer to the total thickness of the pressure-sensitive adhesive layer within the above-mentioned predetermined range, a drying step for adjusting the water content of the polarizer is not required, The optical properties of the polarizing plate are hardly lowered. In addition, since the drying step is unnecessary, the productivity can be improved, for example, the production can be facilitated and efficiently. Furthermore, since the thickness of the polarizer and the total thickness of the pressure-sensitive adhesive layer can be controlled as described above, the yellowing suppression effect can be imparted. Thus, without limiting the constituent components and / or composition of the polarizer and the protective film constituting the polarizer, A polarizer or a protective film may be used in combination. For this reason, it is also advantageous in terms of being able to select a material that is easy to obtain and an inexpensive material, thereby making it possible to lower the production cost. Further, by specifying the constituent components and / or compositions of the polarizer and the protective film constituting the polarizing plate, a higher yellowing suppressing effect can be imparted.

<Polarizer>

In the present invention, the polarizer includes a polarizer. The polarizer is a film having a function of extracting linearly polarized light from incident natural light, and is a polyvinyl alcohol based resin film containing a dichroic dye. As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymer). Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and examples thereof include polyvinyl formal modified with aldehydes, polyvinyl acetal, and polyvinyl butyral. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000.

Such a polyvinyl alcohol-based resin film can be used as the original film of the polarizer. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventionally known method. The thickness of the original film made of a polyvinyl alcohol-based resin is not particularly limited, but it is 10 to 150 占 퐉, preferably 15 to 100 占 퐉, more preferably 20 to 80 占 퐉 in consideration of easiness of stretching .

The polarizer is usually a step of uniaxially stretching the polyvinyl alcohol based resin film, a step of adsorbing the dichroic dye by staining the polyvinyl alcohol based resin film with a dichroic dye, a step of adsorbing the dichroic dye to the polyvinyl alcohol- A step of treating the resin film with an aqueous solution of boric acid, and a step of washing with water after treatment with an aqueous solution of boric acid. Further, by dying the polyvinyl alcohol-based resin film with a dichroic dye, the dichroic dye is included in the polyvinyl alcohol-based resin film. When a polarizer is produced by such a production method, the polarizer is a stretched polyvinyl alcohol based resin film containing a dichroic dye.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be carried out before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to perform uniaxial stretching in these plural steps. In the uniaxial stretching, the uniaxial stretching may be performed between rolls having different circumferential velocities, or may be uniaxially stretched using a heat roll. The uniaxial stretching may be dry stretching in which drawing is performed in the air, or wet stretching in which stretching is performed in a state in which a polyvinyl alcohol based resin film is swollen with a solvent. The stretching magnification is preferably 8 times or less, more preferably 7.5 times or less, and still more preferably 7 times or less from the viewpoint of suppressing the deformation of the polarizer. The stretching magnification is usually 4.5 times or more from the viewpoint of developing the function as a polarizer. By setting the stretching magnification within the above range, deformation of the polarizer with time can be suppressed.

As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, there is a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, for example, iodine or a dichroic dye is used. The dichroic dye includes, for example, a dichroic direct dye comprising a disazo compound such as C. I. DIRECT RED 39, a dichroic direct dye comprising a trisazo, a tetrakisazo compound and the like. It is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol resin film is dipped in an aqueous solution containing iodine and potassium iodide is generally employed. The content of iodine in this aqueous solution is usually 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually 0.5 to 20 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 占 폚, and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1800 seconds.

The film may be immersed in water to facilitate dyeing before swelling the polyvinyl alcohol based resin film in an aqueous solution containing iodine and potassium iodide. The temperature of the immersion treatment is usually 20 to 80 占 폚, preferably 30 to 60 占 폚, and the immersion time (dyeing time) is usually 20 to 1800 seconds.

When a dichroic dye is used as the dichroic dye, a method of dying and dyeing the polyvinyl alcohol resin film into an aqueous solution containing a water-soluble dichroic dye is generally employed. The content of the dichroic dye in the aqueous solution is usually 1 × 10 ^-4 to 10 mass parts, preferably 1 × 10 ^{-3 to} 1 mass parts, and more preferably 1 × 10 ^-3 To 1 x 10 ^-2 parts by mass. The aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. When a dichroic dye is used as the dichroic dye, the dye aqueous solution used for dyeing usually has a temperature of 20 to 80 占 폚, and the dipping time (dyeing time) in this aqueous solution is usually 10 to 1800 seconds.

The boric acid treatment after dyeing with the dichroic dye can be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution of boric acid. The amount of boric acid in the boric acid aqueous solution is usually 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution of boric acid contains potassium iodide. The amount of potassium iodide in the boric acid aqueous solution is usually 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersing time in the aqueous boric acid solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, more preferably 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 占 폚 or higher, preferably 50 to 85 占 폚, and more preferably 60 to 80 占 폚.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment can be carried out, for example, by immersing the boric acid-treated polyvinyl alcohol resin film in water. The water temperature in the water washing treatment is usually 5 to 40 캜, and the immersing time is usually 1 to 120 seconds. After washing with water, drying treatment is carried out to obtain a polarizer. Drying can be performed using a hot-air dryer or a far-infrared heater. The temperature of the drying treatment is usually 30 to 100 占 폚, preferably 40 to 95 占 폚, and more preferably 50 to 90 占 폚. The drying treatment time is usually 40 to 600 seconds, preferably 60 to 500 seconds, and more preferably 120 to 400 seconds.

As described above, the polarizer can be obtained by subjecting the polyvinyl alcohol-based resin film to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment.

The absorbance A ₇₀₀ of the thus obtained polarizer at a wavelength of 700 nm is preferably 5.5 or less, more preferably 5.0 or less, even more preferably 4.5 or less, and particularly preferably 4.2 or less. The absorbance A ₇₀₀ is related to the content of I ₅ complex in the polarizer. If the I ₅ complex is too large, an iodide ion of I ₃ ^- or I ^- is generated from the I ₅ complex in the durability test to accelerate the reaction of polyenes . The absorbance A ₇₀₀ may be 3.0 or more, preferably 3.5 or more, and more preferably 3.7 or more. If the absorbance A ₇₀₀ is too low, the I ₅ complex is broken in the durability test and the relative amount is reduced, so absorption near a wavelength of 700 nm becomes insufficient and the polarizer may change in some cases. The absorbance A ₇₀₀ of the polarizer can be controlled by, for example, adjusting the temperature of the water in the water washing treatment at the time of producing the polarizer.

The absorbance A ₇₀₀ of the polarizing plate can be measured using a spectrophotometer such as a spectrophotometer at the time of extinction, and is calculated from the following formula.

A ₇₀₀ = -log [(TD transmittance (%) at wavelength 700 nm) / 100]

The incident light is measured by using polarized light parallel to the absorption axis direction of the polarizer. In this formula, &quot; TD transmittance &quot; is the transmittance when the direction of the polarized light coming from the Glan Thompson prism is perpendicular to the transmission axis of the polarizer. For example, it can be measured using V7100, a spectrophotometer having an integral sphere manufactured by Nippon Bunko Co., Ltd.

In a preferred embodiment, the polarizing plate may have a protective film (in particular, a transparent protective film) laminated on at least one surface of the polarizer. The protective film contributes to prevention of shrinkage and expansion of the polarizer, prevention of deterioration of the polarizer due to temperature, humidity, ultraviolet rays, etc. Thus, in the optical laminate of the present invention, the protective film is provided on at least one surface of the polarizer, Is preferably laminated.

The material constituting the protective film is preferably excellent in transparency, mechanical strength, thermal stability and / or isotropy. Examples thereof include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulosic polymers such as diacetylcellulose and triacetylcellulose, acrylic polymers such as polymethylmethacrylate, polystyrene and acrylonitrile-styrene copolymer (AS Resin), and polycarbonate-based polymers. Further, it is also possible to use polyolefin-based polymers such as polyethylene, polypropylene and ethylene-propylene copolymer, cyclic olefin-based polymers having a cyclo- or norbornene structure, amide-based polymers such as vinyl chloride-based polymers, nylon and aromatic polyamides, , A sulfone polymer, a polyether sulfone polymer, a polyether ether ketone polymer, a polyphenylene sulfide polymer, a vinyl alcohol polymer, a vinylidene chloride polymer, a vinyl butyral polymer, an arylate polymer, a polyoxymethylene polymer Polymers, epoxy-based polymers, blends of the above polymers, and the like are examples of polymers constituting the protective film. The protective film may be formed as a cured layer of a thermosetting or ultraviolet-curable resin such as acrylic, urethane, acrylic urethane, epoxy, or silicone. Among them, those having a hydroxyl group having reactivity with an isocyanate crosslinking agent are preferable, and a cellulose-based polymer is particularly preferable.

The thickness of the protective film is not particularly limited, but is generally 500 탆 or less, preferably 1 to 300 탆, more preferably 5 to 200 탆, and further preferably 10 to 100 탆. The protective film may be provided with an optical compensation function.

The surface of the protective film not adjacent to the polarizer may have a surface treatment layer and may have an optical layer such as a hard coat layer, an antireflection layer, a sticking prevention layer, an antiglare layer or a diffusion layer. These optical layers may be bonded to the protective film through a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive described later.

The hard coat layer is intended to prevent scratches on the surface of the polarizing plate and is formed by a method of adding a cured film excellent in hardness, slipperiness, and the like by an ultraviolet curable resin such as acrylic or silicone to the surface of the protective film . The antireflection layer is intended to prevent reflection of external light on the surface of the polarizing plate, and can be achieved by forming a conventional antireflection film or the like. The anti-sticking layer is intended to prevent adhesion to the adjacent layer.

The anti-glare layer is intended to prevent external light from being reflected from the surface of the polarizing plate and to inhibit the visibility of the light transmitted through the polarizing plate. For example, the anti-glare layer may be formed by a roughening method using sandblasting or embossing, By adding a micro concavo-convex structure to the surface of the protective film. Examples of the fine particles contained for forming the surface micro concavo-convex structure include fine particles having an average particle diameter of 0.5 to 50 占 퐉, which can be made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, Organic fine particles comprising inorganic fine particles, crosslinked or uncrosslinked polymers, and the like. In the case of forming the surface micro concavo-convex structure, the content of the fine particles is usually 2 to 50 parts by mass, preferably 5 to 25 parts by mass relative to 100 parts by mass of the transparent resin forming the surface fine unevenness structure. The anti-glare layer may also serve as a diffusion layer (time magnification function or the like) for diffusing the polarized-plate transmitted light to enlarge the viewing angle and the like.

The antireflection layer, anti-sticking layer, diffusion layer, antiglare layer, etc. may be provided on the protective film itself to provide a separate optical layer as a separate member from the protective film. These optical layers may be bonded to the protective film through a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive described later.

In the present invention, the protective film preferably has a moisture permeability of at least 200 g / m 2 24 hours, more preferably at least 400 g / m 2 24 hours, further preferably at least 600 g / m 2 24 hours. When the moisture permeability of the protective film is not lower than the lower limit described above, the yellowing of the optical laminate of the present invention over time can be further suppressed. It is preferable that a protective film having a moisture permeability equal to or lower than the lower limit value is present on at least one side of the polarizer and more preferably exists on both sides of the polarizer. The moisture permeability of the protective film is usually 2000 g / m 2 24 hours or less. In the present invention, the moisture permeability can be measured according to JIS Z0208: 1976 under the conditions of a temperature of 40 DEG C and a humidity of 90% RH.

The polarizer and the protective film may be bonded through an adhesive layer. The adhesive constituting the adhesive layer is not particularly limited, and various adhesives can be mentioned. Examples of the adhesive include an active energy ray curable adhesive, an aqueous adhesive, an organic solvent adhesive, and a solventless adhesive. Among them, an active energy ray curable adhesive and an aqueous adhesive are preferable from the viewpoint of thinning the formed adhesive layer. Furthermore, from the viewpoint of further suppressing yellowing over time of the optical laminate, a layer composed of an active energy ray curable adhesive (hereinafter also referred to as an &quot; active energy ray curable adhesive layer &quot;) is more preferable, , And a protective film laminated on at least one surface of the polarizer or on both surfaces of the polarizer through an active energy ray-curable adhesive layer. In the case of having a protective film on both sides of the polarizer, the adhesive applied on one surface of the polarizer and the adhesive applied on the other surface of the polarizer may be the same or different. The polarizer and the protective film may be bonded to each other through a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive, which will be described later, in place of the adhesive layer.

The active energy ray-curable adhesive is an adhesive that cures by irradiating active energy rays such as light. In this case, the resulting cured layer becomes an adhesive layer. Examples of the adhesive include an active energy ray curable adhesive containing an epoxy compound curable by cationic polymerization as a curable component and an active energy ray curable adhesive containing a (meth) acrylic acid based compound curable by radical polymerization have.

Examples of the epoxy compound suitably usable include a hydrogenated epoxy compound obtained by reacting epichlorohydrin with an alicyclic polyol obtained by subjecting an aromatic ring to a hydrogenation reaction in an aromatic ring of an aromatic polyol (a glycidyl ester of a polyol having an alicyclic ring Diesters); Aliphatic epoxy compounds such as aliphatic polyhydric alcohols or polyglycidyl ethers of alkylene oxide adducts thereof; And an alicyclic epoxy compound which is an epoxy compound having at least one epoxy group bonded to an alicyclic ring in the molecule.

The active energy ray-curable adhesive may further contain a (meth) acrylic acid-based compound which is radically polymerizable as a curable component. Examples of the (meth) acrylic acid-based compound include (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule; (Meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers obtained by reacting two or more kinds of functional group-containing compounds and having at least two (meth) acryloyloxy groups in the molecule.

When the active energy ray curable adhesive contains an epoxy compound curable by cationic polymerization as a curable component, it preferably contains a photo cationic polymerization initiator. Examples of the photo cationic polymerization initiator include aromatic diazonium salts; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; Iron-arene complexes and the like. When the active energy ray curable adhesive contains a radically polymerizable curable component such as a (meth) acrylic acid compound, it preferably contains a photo radical polymerization initiator. Examples of the photo radical polymerization initiator include an acetophenone-based initiator, a benzophenone-based initiator, a benzoin ether-based initiator, a thioxanthone-based initiator, xanthone, fluorenone, camphorquinone, benzaldehyde and anthraquinone.

The active energy ray curable adhesive may contain a cationic polymerization accelerator such as oxetane or polyol, a photosensitizer, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, , An antistatic agent, a leveling agent, and / or a solvent.

When an active energy ray-curable adhesive is used, the active energy ray-curable adhesive is cured by irradiating an active energy ray. A light source of an active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, a low energy mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, Wave excited mercury lamps and metal halide lamps are preferable.

The light irradiation intensity to the active energy ray curable adhesive is appropriately determined according to the composition of the active energy ray curable adhesive and is not particularly limited, but the irradiation intensity in the wavelength range effective for activation of the polymerization initiator is preferably 0.1 to 6000 mW / Cm2, more preferably 10 to 1000 mW / cm2, and still more preferably 20 to 500 mW / cm2. When the irradiation intensity is within the above range, the reaction time can be secured, and the yellowing of the epoxy resin and deterioration of the polarizer due to heat radiated from the light source and heat generation during curing of the active energy ray curable adhesive can be suppressed. The light irradiation time for the active energy ray-curable adhesive is appropriately selected according to the active energy ray-curable adhesive to be cured and is not particularly limited, but the integrated light quantity expressed by the product of the irradiation intensity and the irradiation time is preferably MJ / m &lt; 2 &gt;, more preferably 50 to 1,000 mJ / m &lt; 2 &gt;, and further preferably 80 to 500 mJ / m & When the total amount of light to the active energy ray-curable adhesive is within the above range, a sufficient amount of active species derived from the polymerization initiator can be generated sufficiently to allow the curing reaction to proceed more surely, and the irradiation time does not become excessively long, Lt; / RTI &gt;

When the active energy ray-curable adhesive is cured by irradiation of an active energy ray, various functions of the polarizing plate, such as polarizing degree, transmittance and hue of the polarizer, and transparency of various films constituting the protective film and optical layer, It is preferable to carry out the curing under the condition that it is not used.

The water-based adhesive is obtained by dissolving the adhesive component in water or a mixed solvent of water and a hydrophilic organic solvent (for example, an alcohol solvent, an ether solvent, an ester solvent, etc.), or an adhesive component dispersed in water. As the adhesive component, for example, an adhesive containing a polyvinyl alcohol-based resin or a urethane resin can be mentioned. The organic solvent-based adhesive is an organic solvent in place of water or a mixed solvent of water and a hydrophilic organic solvent in an aqueous adhesive.

As the water-based adhesive, for example, a polyvinyl alcohol-based resin adhesive and an aqueous-based urethane-based emulsion adhesive may be cited. Examples of the organic solvent-based adhesive include a liquid-type urethane-based adhesive. On the other hand, examples of the solventless adhesive include a one-component urethane adhesive.

When the adhesive includes a polyvinyl alcohol-based resin as an adhesive component, the polyvinyl alcohol-based resin may be a partially saponificated polyvinyl alcohol, a fully saponified polyvinyl alcohol, a carboxyl group-modified polyvinyl alcohol, an acetoacetyl group-modified polyvinyl alcohol, Modified polyvinyl alcohol resins such as polyvinyl alcohol modified with an alkyl group, polyvinyl alcohol modified with an amino group, and the like. Normally, an adhesive containing a polyvinyl alcohol-based resin as an adhesive component is prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of water.

The adhesive containing a polyvinyl alcohol-based resin as an adhesive component preferably contains a curing component such as glyoxal and water-soluble epoxy resin and / or a crosslinking agent in order to improve the adhesiveness. Examples of the water-soluble epoxy resin include polyamines obtained by reacting epichlorohydrin with polyamide amines obtained by reacting polyalkylene polyamines such as diethylene triamine and triethylene tetramine with dicarboxylic acids such as adipic acid, Amide polyamine epoxy resins can be suitably used. Examples of commercially available products of such polyamide polyamine epoxy resins include Sumirez Resin 650 (Daokakagaku Kogyo Co., Ltd.), Sumirez Resin 675 (Daokakagaku Kogyo Co., Ltd.), WS-525 (Manufactured by Nippon PMC Co., Ltd.). The amount of the curing component and / or the crosslinking agent to be added (when added together, the total amount thereof) is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol-based resin. When the addition amount of the curable component and / or the cross-linking agent is within the above range, the adhesive property is improved and an adhesive layer exhibiting good adhesiveness can be formed.

When a urethane resin is contained as an adhesive component, it is preferable to use a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group. Here, the polyester-based ionomer type urethane resin is a urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the skeleton thereof. Such an ionomeric urethane resin is suitable as an aqueous adhesive since it emulsifies directly in water without using an emulsifier. The polyester-based ionomer-type urethane resin itself is known, and Japanese Patent Laid-Open No. 7-97504, for example, discloses an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium, -70140 and 2005-208456 disclose a method in which a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group is used as an adhesive and a polarizer made of a polyvinyl alcohol- Based resin film are bonded to each other.

A water-soluble chelate compound may be contained as an adhesive component. The water-soluble chelate compound contained in the adhesive composition can increase the degree of crosslinking between the adhesive layer and the protective film such as a polyvinyl alcohol-based polarizer, a cellulose-based film, and an olefin-based film, thereby improving the adhesive strength and water resistance. As the water-soluble chelate compound, zinc chloride, cobalt chloride, magnesium chloride, magnesium acetate, aluminum nitrate, zinc nitrate, zinc sulfate and the like can be added. From the viewpoint of improving durability, zinc chloride and zinc nitrate are preferable.

The application of the adhesive to the polarizer and / or the protective film to be bonded to the polarizer and / or the protective film can be performed by a known method. Examples of the method include a casting method, a Meyer bar coating method, a gravure coating method, a comma coater method, Blade method, die coating method, dip coating method, spraying method and the like can be used. The flexible method is a method in which a film as an object to be coated is moved in a substantially vertical direction, in a substantially horizontal direction, or in an oblique direction between the two, and the adhesive is flown down on the surface of the film. After the adhesive is applied, the polarizer and the protective film bonded thereto are overlapped with each other, and the film is sandwiched by a nip roll or the like. The bonding of the film using the nip roll can be carried out by, for example, a method of applying an adhesive, pressing the film with a roll or the like and uniformly pressing the film, applying the adhesive, passing the film through a roll and a roll, . In this case, the material of the roll used may be metal or rubber. Further, in the case of pressing and stretching the film between a plurality of rolls, the plurality of rolls may be the same material or different materials.

After bonding and drying, the adhesive is cured to obtain a polarizing plate comprising a polarizer, an adhesive layer and a protective film. This drying treatment is carried out, for example, by spraying hot air. The temperature varies depending on the type of the solvent, but is usually 30 to 200 캜, preferably 35 to 150 캜, more preferably 40 to 100 캜, Is in the range of 60 to 100 占 폚. The drying time is usually 20 to 1200 seconds.

After drying, the adhesive layer may be cured for at least half a day, preferably several days, at room temperature or higher to obtain sufficient adhesive strength. The curing temperature is preferably in the range of 30 to 50 占 폚, and more preferably in the range of 35 to 45 占 폚. When the curing temperature is within the above-mentioned range, so-called &quot; fastening &quot; in the rolled state is hardly caused. The humidity at the time of curing is not particularly limited, and the relative humidity may be in the range of 0 to 70% RH. The curing time is usually from half day to 20 days, preferably from 1 to 10 days, more preferably from 2 to 7 days.

The surface of adhesion between the polarizer and the protective film may be appropriately subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, saponification treatment, etc., in order to improve adhesion. As the saponification treatment, there may be mentioned a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide.

The thickness of the adhesive layer is usually 0.001 to 10 占 퐉, preferably 0.01 to 5 占 퐉, more preferably 0.01 to 2 占 퐉, and still more preferably 0.02 to 1 占 퐉. When the thickness of the adhesive layer is within the above range, sufficient adhesiveness can be ensured, appearance is also preferable, and further it can contribute to thinning of the polarizing plate, which is suitable for the optical laminate of the present invention.

In the optical laminate of the present invention, the polarizing plate may further include an optical film or optical layer such as a retardation film, a time compensating film, a luminance improving film, an antiglare film, an antireflection film and / or a condensing film, There may be. These optical films and optical layers may be bonded to the polarizing plate through a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive described later.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an orientation film of a liquid crystal polymer, a film supported with an orientation layer of a liquid crystal polymer, and the like have. The stretching treatment can be performed by, for example, a roll stretching method, a long-gap stretch stretching method (long gap stretching method), a tenter stretching method, a tubular stretching method and the like. The draw ratio is generally 1.1 to 3 times in the case of uniaxial drawing. The thickness of the retardation film is not particularly limited, but is generally 10 to 200 占 퐉, preferably 20 to 100 占 퐉.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, Polyolefin having a norbornene structure, polyvinyl chloride, cellulose, polyvinyl alcohol, polyvinyl alcohol, polyamide, polyamide, polyvinyl alcohol, polyvinyl alcohol, Based polymer, a ternary system, a ternary system various copolymers, a graft copolymer, and a blended product thereof. These polymer materials become an oriented product (stretched film) by stretching or the like.

Examples of the liquid crystal polymer include various polymers having a main chain type or a side chain type in which a conjugated linear group (mesogen) imparting liquid crystal alignability is introduced into the main chain or side chain of the polymer. Specific examples of the main chain type liquid crystal polymer include polyester type liquid crystal polymers, discotic polymers and cholesteric polymers having a structure in which a mesogen group is bonded to a spacer imparting bendability, such as a nematic orientation. As specific examples of the side chain type liquid crystal polymer, polysiloxane, polyacrylate, polymethacrylate or polymalonate is used as the main chain skeleton and a spacer moiety having a conjugated atomic group as a side chain is used as a para- And having a mesogen portion formed thereon. These liquid crystal polymers can be obtained by, for example, developing a solution of a liquid crystal polymer on an oriented surface such as a surface obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, Heat treatment is performed.

The retardation film may be any retardation film that has a retardation depending on the intended use such as various wavelength plates or ones intended to compensate for coloring due to birefringence of the liquid crystal layer or for the purpose of visual observation or the like, and may be formed by laminating two or more kinds of retardation films, Or the like may be used.

The time-compensating film is a film for widening the viewing angle so that an image can be seen relatively clearly even when viewing the screen of the liquid crystal display device in a slightly inclined direction with respect to the screen.

Examples of such a time-compensating film include an orientation film such as a retardation film or a liquid crystal polymer, and an orientation film such as a liquid crystal polymer supported on a transparent substrate. A conventional retardation film uses a polymer film having birefringence uniaxially stretched in the plane direction, whereas the retardation film used as a time compensation film includes a polymer film having birefringence stretched biaxially in the plane direction, A two-direction stretched film such as a polymer having a birefringence in which the refractive index in the thickness direction is controlled and a warp-oriented film, which are uniaxially stretched and also stretched in the thickness direction, are used. Examples of the oblique orientation film include those obtained by bonding a heat shrinkable film to a polymer film and stretching and / or shrinking the polymer film under the action of the shrinking force by heating, and those obtained by obliquely aligning the liquid crystal polymer. As the material raw material polymer of the retardation film, the same polymer as that described in the above-mentioned retardation film is used, and for the purpose of prevention of coloring due to a change in the viewing angle based on the phase difference caused by the liquid crystal cell and enlargement of the viewing angle of good visibility Can be suitably selected and used.

Further, from the viewpoint of attaining a wide viewing angle of good visibility, a time compensating film in which an optically anisotropic layer comprising an orientation layer of a liquid crystal polymer, in particular, an oblique orientation layer of a discotic polymer, is supported by a triacetylcellulose film is suitably used.

<Pressure-sensitive adhesive layer>

In the present invention, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are laminated on the surface of the polarizing plate. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are composed of a pressure-sensitive adhesive. The pressure-sensitive adhesives constituting the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be the same or different.

In the present invention, the pressure-sensitive adhesive comprises a resin. The type of the resin contained in the pressure-sensitive adhesive is not particularly limited, and examples thereof include (meth) acrylic resin, silicone resin, urethane resin and rubber. The pressure-sensitive adhesive may contain one or more resins.

It is preferable to employ a (meth) acrylic resin (A) as the resin in view of the ability to easily impart functionality to the pressure-sensitive adhesive by selecting the kind of monomer to be introduced into the resin. As the (meth) acrylic resin (A), a polymer containing as a main component a structural unit derived from (meth) acrylic acid ester (hereinafter also referred to as "monomer (I)") represented by the following formula . In the present invention, &quot; a polymer containing a structural unit derived from a monomer (I) as a main component &quot; means that a structural unit derived from the monomer (I) is preferably a structural unit derived from a monomer By mass or more, and more preferably 60% by mass or more, such as 80% by mass or more. In this case, the structural unit derived from the monomer (I) is usually contained in an amount of 100 mass% or less, preferably 90 mass% or less, with respect to the total structural units constituting the polymer.

In the formula (I), R ¹ is a hydrogen atom or a methyl group, and R ² usually has 14 or less carbon atoms, preferably 10 or less, and usually 1 or more alkyl or aralkyl groups.

In one embodiment of the present invention, the (meth) acrylic resin (A) is a copolymer of a structural unit derived from a (meth) acrylic acid ester (monomer (I) Derived structural unit, preferably a structural unit derived from a (meth) acrylic acid-based compound having a polar functional group. Examples of the polar functional group include a carboxyl group, a hydroxyl group, an amino group, and a heterocyclic group including an epoxy ring. Examples of the (meth) acrylic acid compound having a polar functional group include (meth) acrylic acid, 2- (dimethylamino) ethyl acrylate, 2-hydroxyethyl (meth) acrylate and glycidyl acrylate. Further, the (meth) acrylic resin (A) may contain a structural unit derived from a monomer having no polar functional group other than the monomer (I). (Meth) acrylic acid-based compound having a structural unit derived from a monomer having one olefinic double bond and at least one aromatic ring in the molecule, preferably an aromatic ring, as a structural unit (monomer) Derived structural units. In the present specification, (meth) acrylic acid means that acrylic acid or methacrylic acid may be used, and "(meth)" when referring to (meth) acrylate or the like is also intended.

Specific examples of the monomer (I) in which R ² is an alkyl group include linear alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, n-octyl acrylate and lauryl acrylate; Branched acrylic acid alkyl esters such as isobutyl acrylate, 2-ethylhexyl acrylate and isooctyl acrylate; Linear methyl methacrylate alkyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate and lauryl methacrylate; Examples of branched alkyl methacrylates include isobutyl methacrylate, 2-ethylhexyl methacrylate, and dioctyl methacrylate.

Of these, n-butyl acrylate is preferable, and specifically, n-butyl acrylate accounts for 50% by mass or more among all the structural units (monomers) constituting the (meth) acrylic resin (A) It is desirable to satisfy the following requirements.

Among the monomers (I), R ² is an aralkyl group, and specific examples thereof include benzyl acrylate and benzyl methacrylate.

These monomers (I) may be used alone or in combination.

The alkyl group or aralkyl group constituting R ² in the formula (I) may be such that the hydrogen atom thereof is substituted with a group -O- (C ₂ H ₄ O) _n -R ³ .

When the hydrogen atom of the alkyl group or aralkyl group constituting R ² in the formula (I) is substituted with a group -O- (C ₂ H ₄ O) _n -R ³ , n is 0 or an integer of 1 to 4 More preferably 0, 1 or 2. R ³ is an alkyl group or an aryl group having 12 or less carbon atoms and may be straight-chain or branched if the alkyl group has 3 or more carbon atoms. Examples of the aryl group constituting R ³ include, in addition to phenyl or naphthyl, a phenyl group substituted with a nucleophilic alkyl such as tolyl, xylyl, ethylphenyl and the like, biphenyl (or phenylphenyl), and the like. R ³ is particularly preferably an aryl group thereof.

Expression and R ² is an alkyl group or an aralkyl group in (I), also the hydrogen atoms of the alkyl group or the aralkyl group of _{^{R 2 -O- (C 2 H 4}} O) n ( meth) acrylic acid which is substituted with -R ³ Specific examples of the esters include 2-methoxyethyl acrylate, ethoxymethyl acrylate, 2-phenoxyethyl acrylate, 2- (2-phenoxyethoxy) ethyl acrylate and 2- (o-phenylphenoxy) ethyl acrylate Alkoxyalkyl-, aryloxyalkyl- or aryloxyethoxyalkyl-esters of acrylic acid; Methoxyethyl methacrylate, ethoxymethyl methacrylate, 2-phenoxyethyl methacrylate, 2- (2-phenoxyethoxy) ethyl methacrylate and 2- (o-phenylphenoxy) methacrylate Alkoxyalkyl-, aryloxyalkyl- or aryloxyethoxyalkyl-esters of methacrylic acid such as ethyl, and the like.

The (meth) acrylic resin (A) in the present invention may contain a structural unit derived from a monomer having no polar functional group other than the monomer (I). Examples of the monomer having no polar functional group other than the monomer (I) include (meth) acrylic acid ester monomers having an alicyclic structure in the molecule, styrene monomers, vinyl monomers, (meth) acrylamide derivatives, Monomers having an acryloyl group, and the like.

(Meth) acrylic acid ester monomers having an alicyclic structure in the molecule will be described. The alicyclic structure is a cycloparaffin structure having a carbon number of usually 5 or more, preferably 5 to 7 or so. Specific examples of the acrylic acid ester monomer having an alicyclic structure include acrylic acid esters such as acrylic acid esters such as isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, cyclohexyl α-ethoxyacrylate, and cyclohexylphenyl acrylate. Specific examples of the methacrylic acid ester monomer having an alicyclic structure include methacrylic acid diisocyanate such as isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, cyclododecyl methacrylate, methylcyclohexyl methacrylate, Trimethylcyclohexyl methacrylate, tert-butylcyclohexyl methacrylate, cyclohexylphenyl methacrylate, and the like.

Examples of the styrene-based monomer include, in addition to styrene, alkylstyrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene; Halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene and iodostyrene; Also, nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene, and the like are available.

Examples of the vinyl monomer include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; Vinyl halides such as vinyl chloride and vinyl bromide; Vinylidene halides such as vinylidene chloride; Nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; Conjugated diene monomers such as butadiene, isoprene and chloroprene; Acrylonitrile, methacrylonitrile, and the like.

Examples of the (meth) acrylamide derivatives include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3- hydroxypropyl) (Meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N- (5-hydroxypentyl) (Meth) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (propoxymethyl) (meth) (Meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- (Meth) acrylamide, N- [2- (2-oxo-1-imidazolidinyl) ethyl] (meth) acrylamide, 2-acryloylamino- Methyl-1-propanesulfonic acid and the like.

Examples of the monomer having plural (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, (Meth) acrylate such as ethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate and tripropylene glycol di Monomers having (meth) acryloyl groups; (Meth) acryloyl groups in the molecule, such as trimethylolpropane tri (meth) acrylate, and the like.

The monomer constituting the (meth) acrylic resin (A) has a polar functional group other than the (meth) acrylic acid ester represented by the formula (I) and the monomer having a polar functional group and / or the monomer (I) Or two or more monomers each of which is not contained.

The weight average molecular weight (Mw) of the resin contained in the pressure-sensitive adhesive in terms of standard polystyrene by gel permeation chromatography (GPC) is not particularly limited, but Mw is preferably in the range of 500,000 to 2,000,000, And more preferably in the range of 0.5 to 1.5 million. When the weight average molecular weight in terms of standard polystyrene is 500,000 or more, the adhesiveness under high temperature and high humidity is improved, and there is a tendency that the possibility of lifting or peeling between the transparent plate or the image display cell and the pressure-sensitive adhesive layer tends to decrease. There is a tendency to improve. If the weight average molecular weight is not more than 2,000,000, even if the size of the protective film adhered to the pressure-sensitive adhesive layer changes, the pressure-sensitive adhesive layer follows and fluctuates following the dimensional change. So that white spots and color unevenness tend to be suppressed. The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is not particularly limited, but is preferably in the range of about 3 to 15, for example.

The resin contained in the pressure-sensitive adhesive can be produced by various known methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method and a suspension polymerization method. In the production of the resin, a polymerization initiator may be used, and the amount thereof to be added is about 0.001 to 5 parts by mass based on 100 parts by mass of the total amount of all the monomers used in the production of the resin.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, and the like are used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. As the thermal polymerization initiator, for example, 2,2'-azobisisobutylonitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile Azo compounds such as 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy valeronitrile) Azo compounds such as azobis (2-methylpropionate) and 2,2'-azobis (2-hydroxymethylpropionitrile); Butyl peroxide, lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, Organic peroxides such as neodecanoate, tert-butyl peroxypivalate and (3,5,5-trimethylhexanoyl) peroxide; And inorganic peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide. A redox-type initiator using a peroxide and a reducing agent in combination may also be used as a polymerization initiator.

As the method for producing the (meth) acrylic resin (A), a solution polymerization method is preferable among the methods shown above. A specific example of the solution polymerization method will be described. A desired monomer and an organic solvent are mixed, and a thermal polymerization initiator is added under a nitrogen atmosphere. The solution is heated at a temperature of about 40 to 90 캜, preferably about 50 to 80 캜, Followed by stirring. In order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during polymerization, or may be added in a state dissolved in an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; Esters such as ethyl acetate and butyl acetate; Aliphatic alcohols such as propyl alcohol and isopropyl alcohol; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and the like.

In the present invention, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may contain additives other than the above-mentioned resin. Examples of other additives include crosslinking agents, silane compounds, crosslinking catalysts, weathering stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, organic acids, antistatic agents and organic acid metal salts.

It is also useful to blend an active energy ray (for example, ultraviolet ray) curable compound with the pressure-sensitive adhesive and to cure the pressure-sensitive adhesive layer by irradiating ultraviolet rays after the pressure-sensitive adhesive layer is formed to form a harder pressure-sensitive adhesive layer.

The crosslinking agent that can be included in the pressure-sensitive adhesive is a compound having at least two functional groups capable of crosslinking the resin contained in the pressure-sensitive adhesive. Specific examples thereof include isocyanate compounds, epoxy compounds, metal chelate compounds and aziridine compounds.

The isocyanate compound is a compound having at least two isocyanato groups (-NCO) in the molecule, and examples thereof include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate , Diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and the like. Also, an adduct in which an isocyanate compound is reacted with a polyol such as glycerol or trimethylolpropane, or an isocyanate compound in the form of a dimer, a trimer, or the like can also be used as a crosslinking agent used in a pressure-sensitive adhesive. Two or more isocyanate compounds may be mixed and used.

The epoxy compound is a compound having at least two epoxy groups in the molecule, and examples thereof include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglyceride N, N, N ', N'-tetraglycidyl-m, N, N'-tetramethyl aniline, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, -Xylene diamine, and the like. Two or more kinds of epoxy compounds may be mixed and used.

Examples of the metal chelate compound include compounds in which acetylacetone and ethyl acetoacetate are coordinated to polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium .

The aziridine compound is a compound having at least two skeletons of a three-membered ring composed of one nitrogen atom and two carbon atoms, which is also called ethyleneimine, in the molecule, and examples thereof include diphenylmethane-4,4'-bis (1-aziridine Carboxamide), toluene-2,4-bis (1-aziridine carboxamide), triethylene melamine, isophthaloyl bis-1- (2-methyl aziridine), tris- (1-aziridine carboxamide), trimethylolpropane tris- [beta] -aziridinyl propionate, tetramethylolmethane tris- [beta] -aziridinyl propionate, and the like, .

Among these crosslinking agents, isocyanate compounds, particularly adducts obtained by reacting tolylene diisocyanate with polyol, dimers of tolylene diisocyanate, trimers of tolylene diisocyanate, adducts obtained by reacting hexamethylene diisocyanate with polyol, A dimer of methylene diisocyanate, a trimer of hexamethylene diisocyanate, an adduct in which xylene diisocyanate is reacted with a polyol, an adduct in which hydrogenated xylylene diisocyanate is reacted with a polyol, isophorone diisocyanate and / A mixture of an isocyanate compound and an isocyanate compound obtained by reacting a tolylene diisocyanate with a polyol is preferably used.

The content of the crosslinking agent in the pressure-sensitive adhesive is usually about 0.01 to 5 parts by mass, preferably 0.03 to 2 parts by mass, and more preferably 0.1 to 1.5 parts by mass based on 100 parts by mass of the resin contained in the pressure-sensitive adhesive.

When the optical laminate of the present invention is bonded to a transparent plate (for example, a glass plate) through a pressure-sensitive adhesive, the pressure-sensitive adhesive in the present invention preferably contains a silane-based compound from the viewpoint of improving adhesion with a glass substrate. Particularly, it is preferable to incorporate a silane compound into the resin before the crosslinking agent is blended.

Examples of the silane-based compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyltrimethoxysilane, 3- 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3- , 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropyl Ethoxydimethylsilane, and the like. Two or more silane-based compounds may be used.

The silane-based compound may be a silicone oligomer type. When a silicone oligomer is expressed in the form of (monomer) - (monomer) copolymer, for example, the following may be mentioned.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer And 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymers; copolymers containing mercaptopropyl groups;

Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltri A mercapto methyl group-containing copolymer such as a methoxy silane-tetraethoxy silane copolymer;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane copolymer Methoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer and 3-methacryloyloxypropylmethyl di Copolymers containing methacryloyloxypropyl groups, such as methoxy silane-tetraethoxy silane copolymers;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane- 3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer Copolymers containing acryloyloxypropyl groups, such as polymers;

Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer Polymer, vinyl methyl dimethoxy silane-tetramethoxy silane copolymer, vinyl methyl dimethoxy silane-tetraethoxy silane copolymer, vinyl methyl diethoxy silane-tetramethoxy silane copolymer and vinyl methyl diethoxy silane-tetraethoxy Vinyl group-containing copolymers such as silane copolymers, and the like.

These silane-based compounds are often liquid. The content of the silane compound in the pressure-sensitive adhesive is usually about 0.01 to 10 parts by mass, preferably 0.03 to 2 parts by mass, and more preferably 0.03 to 1 part by mass based on 100 parts by mass of the resin contained in the pressure-sensitive adhesive.

The thickness of the first pressure sensitive adhesive layer and the thickness of the second pressure sensitive adhesive layer may be the same or different. As described above, the thickness of the first pressure sensitive adhesive layer and the thickness of the second pressure sensitive adhesive layer are set so that the ratio (T2 / T1) of the total thickness T1 to T2 of all the pressure sensitive adhesive layers in the optical laminate ) Is 0.6 or less, it may be appropriately determined independently of each other.

In one embodiment, the optical laminate of the present invention may be bonded to an image display cell described later through a first pressure-sensitive adhesive layer, or may be bonded to a transparent plate described later through a second pressure-sensitive adhesive layer. At this time, the thickness of the second pressure sensitive adhesive layer and the thickness of the first pressure sensitive adhesive layer may be the same or different, and the thickness of the second pressure sensitive adhesive layer may be thicker than the thickness of the first pressure sensitive adhesive layer.

The thickness of the first pressure-sensitive adhesive layer (pressure-sensitive adhesive layer on the cell side) is preferably not less than 3 占 퐉, more preferably not less than 5 占 퐉, still more preferably not less than 10 占 퐉, from the viewpoints of suppression of yellowing of the optical laminate, Is preferably 30 占 퐉 or less, more preferably 27 占 퐉 or less, and further preferably 25 占 퐉 or less, from the viewpoint of thinning of the optical laminate. The thickness of the second pressure-sensitive adhesive layer (pressure-sensitive adhesive layer on the transparent plate side) is preferably not less than 20 占 퐉, more preferably not less than 30 占 퐉, still more preferably not less than 40 占 퐉 And is preferably 300 占 퐉 or less, more preferably 280 占 퐉 or less, further preferably 250 占 퐉 or less, from the viewpoint of thinning of the optical laminate. When the pressure-sensitive adhesive layer (also referred to as "another pressure-sensitive adhesive layer") other than the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is contained in the optical laminate, the other pressure- , Preferably not less than 3 占 퐉, more preferably not less than 5 占 퐉, and is preferably not more than 30 占 퐉, more preferably not more than 25 占 퐉, from the viewpoint of thinning of the optical laminate.

In the optical laminate of the present invention, a peelable protective sheet may be adhered to each of the surfaces of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer opposite to the polarizing plate. The protective sheet is a sheet used for protecting the exposed surface of the pressure-sensitive adhesive layer before the optical laminate is bonded to the image display cell or the transparent plate from scratches and dirt, and the protective sheet is peeled off to form a first pressure- The image display device of the present invention can be constituted by bonding the second pressure sensitive adhesive layer to the image display cell and the transparent plate respectively. That is, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer all enter the display device without being removed.

Examples of the material constituting the protective sheet include thermoplastic resins such as polyolefin resins such as polyethylene resins and polypropylene resins; Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; Polycarbonate resin; (Meth) acrylic resin, and the like.

The optical laminate of the present invention is used by bonding, for example, between the transparent plate and the image display cell through the pressure-sensitive adhesive layer. The transparent plate plays a role of suppressing warpage of an image display cell such as a liquid crystal cell or protecting an image display cell, and is, for example, a translucent (preferably optically transparent) plate. The transparent plate may have a single-layer structure or a multi-layer structure. The transparent plate is also called a transparent front plate. Examples of the image display cell include a liquid crystal cell (element) and an organic EL cell (element).

Since the transparent plate is disposed on the outermost surface of the final product including the optical laminate of the present invention, it is required to have sufficient durability even when it is used outdoors or outdoors. From this point of view, the transparent plate is preferably made of an inorganic material such as glass or tempered glass, or a polymer film having a Young's modulus of 2 GPa or more. (Young's modulus: 2 to 3 GPa), acrylic resin (Young's modulus: 3 to 4 GPa), polyimide resin (Young's modulus: 3 GPa), and the like are suitable as inorganic materials for glass, To 5 GPa), and a polyethersulfone resin (Young's modulus: 2 to 3 GPa).

The transparent plate may have a color filter layer or a TFT layer in a display, a transparent electrode layer in a touch panel, or a glass or a polymer film printed with an edible layer (decorative layer). That is, in one embodiment of the present invention, the transparent plate may have at least one patterning layer selected from the group consisting of (A) to (D) below.

(A) Color filter layer

(B) TFT layer

(C)

(D)

The touch panel method is not particularly limited, and examples thereof include an electrostatic capacitance method, a surface acoustic wave method, a resistance film method, an electromagnetic induction method, an optical sensor method, and an infrared method. The transparent plate may have functions such as anti-reflection, anti-fouling, electromagnetic shielding, near-infrared shielding, color adjustment, or glass scattering prevention. The transparent plate having such a function may be, for example, at least one film layer having these functions laminated on at least one surface of the transparent plate.

The integration of the transparent plate, the polarizing plate, and the image display cell can be realized by joining them through the pressure-sensitive adhesive layer, and accordingly, the image display apparatus ). &Lt; / RTI &gt; In such an image display apparatus, it is preferable that the refractive index of the pressure-sensitive adhesive is close to or equal to the refractive index of the transparent plate in order to eliminate reflection or scattering of light at the interface between the transparent plate and the polarizing plate to improve visibility. In the image display apparatus of the present invention, the yellowing of the image display portion (display) over time can be suppressed, and the stable image display function can be exhibited in the long term.

INDUSTRIAL APPLICABILITY The optical laminate and the image display device of the present invention can be used for a mobile device such as a television, a personal computer, a mobile phone, a tablet terminal, etc., and have a high suppressing effect on yellowing under a high temperature environment, It can exhibit a stable image display function and can therefore be suitably used particularly in a vehicle-mounted use which is likely to be exposed under more severe temperature conditions. Examples of applications on vehicles include image display devices used in car navigation systems, speed meters, touch panels for air conditioners, back monitors, rear monitors, and the like.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

1. Fabrication of Polarizer (1)

(Average degree of polymerization of about 2400, degree of saponification of 99.9 mol% or more) having a thickness of 60 占 퐉 was vertically uniaxially stretched by about 5 times by dry drawing and immersed in pure water at 60 占 폚 for one minute while maintaining the tension state And then immersed in an aqueous solution at 28 DEG C for 60 seconds in which the mass ratio of iodine / potassium iodide / water was 0.05 / 5/100. Thereafter, the substrate was immersed in an aqueous solution of 72 ° C having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 for 300 seconds. Subsequently, the film was washed with pure water at 26 DEG C for 20 seconds, and then dried at 65 DEG C for 60 seconds to obtain a polarizer (1) having a thickness of 23 mu m in which iodine was adsorbed and oriented on a polyvinyl alcohol film. The absorbance A ₇₀₀ of the polarizer 1 at a wavelength of 700 nm was 4.0.

2. Fabrication of Polarizer (2)

Except that a polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more) having a thickness of 30 占 퐉 was used in place of the polyvinyl alcohol film having a thickness of 60 占 퐉, And a polarizer (2) having a thickness of 12 탆 in which iodine was adsorbed and oriented on an alcohol film was obtained. The absorbance A ₇₀₀ of the polarizer 2 at a wavelength of 700 nm was 4.0.

3. Fabrication of Polarizer (3)

Except that a polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more) having a thickness of 75 占 퐉 was used in place of the polyvinyl alcohol film having a thickness of 60 占 퐉, A polarizer 3 having a thickness of 28 占 퐉 in which iodine was adsorbed and aligned on an alcohol film was obtained. The absorbance A ₇₀₀ of the polarizer 3 at a wavelength of 700 nm was 4.0.

4. Fabrication of Polarizer (4)

A polarizer 4 having a thickness of 12 占 퐉 in which iodine was adsorbed and oriented on a polyvinyl alcohol film was obtained in the same manner as in "Production of Polarizer 2" except that the pure water temperature at the time of washing was changed to 21 占 폚. The absorbance A ₇₀₀ of the polarizer 4 at a wavelength of 700 nm was 3.3.

5. Fabrication of Polarizer (5)

A polarizer 5 having a thickness of 12 占 퐉 in which iodine was adsorbed and oriented on a polyvinyl alcohol film was obtained in the same manner as in "Production of Polarizer 2" except that the pure water temperature at the time of cleaning was changed to 34 占 폚. The absorbance A ₇₀₀ of the polarizer 5 at a wavelength of 700 nm was 4.7.

6. Preparation of waterborne adhesives

3 parts by mass of a carboxyl group-modified polyvinyl alcohol ("KL-318" manufactured by Kuraray Co., Ltd.) was dissolved in 100 parts by mass of water to prepare a polyvinyl alcohol aqueous solution. Subsequently, 1.5 parts by mass of a water-soluble polyamide polyamine epoxy resin (Sumirez Resin 650 (30), solid content concentration 30% by mass, manufactured by Daokakagaku Kogyo Co., Ltd.) was added to 100 parts by mass of water in the above solution, And an aqueous adhesive was obtained by mixing.

7. Preparation of ultraviolet (active energy ray) curing adhesive

80 parts of the following alicyclic epoxy resin (a1) and 20 parts of the aliphatic epoxy resin (a2) were mixed as a curable component, and 4.5 parts of a photo cationic polymerization initiator was added and mixed as solid content to prepare an ultraviolet curable adhesive.

Alicyclic epoxy resin (a1): 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate: "Suloxide (registered trademark) 2021P" manufactured by Daicel Chemical Industries, Ltd.,

Aliphatic epoxy resin (a2): 1,4-butanediol diglycidyl ether: "Denacol (registered trademark) EX-121" manufactured by Nagase Chemtex Co.,

Photo cationic polymerization initiator: triarylsulfonium salt photo cationic polymerization initiator: 50% propylene carbonate solution, "CPI-100P"

[Example 1]

The water-based adhesive was applied to both surfaces of the polarizer 1, and a triacetyl cellulose film (thickness: 40 占 퐉) having a thickness of 40 占 퐉, which had been subjected to corona treatment as a protective film, was applied to one surface of the polarizer 1 via an aqueous adhesive (TAC) ("KC4UA" manufactured by Konica Minolta Opt Co., Ltd., water vapor permeability: 830 g / m 2 · 24 hours) was subjected to corona treatment on the other side of the polarizer 1 via an aqueous adhesive agent ("ZEONOR" manufactured by Nippon Zeon Co., Ltd., moisture permeability: 20 g / m 2 .24 hours) having a thickness of 23 μm and a thickness of 23 μm . Thereafter, the resultant was dried at 80 ° C for 5 minutes, and then cured at 40 ° C and 23% RH for 72 hours. After curing, a first pressure-sensitive adhesive layer having a thickness of 20 占 퐉 was formed on the ZEONOR surface by applying an acrylic pressure-sensitive adhesive (P-119E, manufactured by LINTEC Co., Ltd.) using the bonding apparatus described above. Further, a second pressure-sensitive adhesive layer having a thickness of 20 占 퐉 was formed on the TAC surface side by applying an acrylic pressure-sensitive adhesive (P-119E, manufactured by Lintech Co., Ltd.) using the bonding apparatus described above. Thus, an optical laminate 1 was obtained.

At this time, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of the pressure-sensitive adhesive layer in the optical laminate 1 is 40 m, the thickness T2 of the polarizer is 23 m, 0.58.

[Example 2]

An optical laminate 2 was obtained in the same manner as in Example 1 except that the polarizer 2 was used in place of the polarizer 1. In this case, the total thickness T1 of the pressure-sensitive adhesive layers in the optical laminate 2 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) is 40 占 퐉, the thickness T2 of the polarizer is 12 占 퐉, 0.30.

[Example 3]

An optical laminate (3) was obtained in the same manner as in Example 1, except that the thickness of the second pressure-sensitive adhesive layer was 40 占 퐉. At this time, the total thickness T1 of all the pressure-sensitive adhesive layers in the optical laminate 3 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) is 60 占 퐉, the thickness T2 of the polarizer is 23 占 퐉, 0.38.

[Example 4]

On one side of a triacetylcellulose film (TAC) ("KC4UA" manufactured by Konica Minolta Opt Co., Ltd.) having a thickness of 40 占 퐉, an ultraviolet curable adhesive was applied to a surface of about 2 占 퐉 after curing using a bar coater Respectively. And the polarizer 1 was bonded to the coated surface. Subsequently, a corona discharge treatment was carried out on one side of a non-stretched norbornene resin ("ZEONOR" manufactured by Nippon Zeon Co., Ltd.) having a thickness of 23 탆, and on the corona discharge treated surface, the ultraviolet- Using a bar coater so as to have a film thickness of about 2 mu m. On the coated surface, a polarizer having the triacetyl cellulose film bonded to one side thereof was bonded on the side of the polarizer, thereby producing a laminate. From the side of the acetylcellulose film of this laminate, ultraviolet rays were irradiated using an ultraviolet irradiation device having a belt conveyor (lamp: "D bulb" manufactured by Fusion UV Systems Co., Ltd.) so as to obtain an integrated light quantity of 250 mJ / The curable adhesive was cured.

Thereafter, an acrylic pressure-sensitive adhesive (P-119E, manufactured by LINTEC Co., Ltd.) was applied to the ZEONOR surface side using a bonding apparatus ("LPA3301" manufactured by Fuji Plasma Co., Ltd.) Thereby forming a pressure-sensitive adhesive layer. Further, a second pressure-sensitive adhesive layer having a thickness of 20 占 퐉 was formed on the TAC surface side by applying an acrylic pressure-sensitive adhesive (P-119E, manufactured by Lintech Co., Ltd.) using the bonding apparatus described above. Thus, an optical laminate 4 was obtained.

At this time, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of all the pressure-sensitive adhesive layers in the optical laminate 4 is 40 占 퐉, the thickness T2 of the polarizer is 23 占 퐉, 0.58.

[Example 5]

An acrylic pressure-sensitive adhesive (P-119E, manufactured by LINTEC CO., LTD.) Was applied to one side of the polarizer 1 using a bonding apparatus ("LPA3301" manufactured by Fuji Plasma Co., Ltd.) 1 pressure-sensitive adhesive layer. A second pressure-sensitive adhesive layer having a thickness of 20 占 퐉 was formed on the other surface of the polarizer 1 by applying an acrylic pressure-sensitive adhesive (P-119E, manufactured by Rin Tec Corporation) using the bonding apparatus described above. Thus, an optical laminate 5 was obtained.

At this time, the total thickness T1 of all the pressure-sensitive adhesive layers in the optical laminate 5 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) is 40 占 퐉, the thickness T2 of the polarizer is 23 占 퐉, 0.58.

[Example 6]

An optical laminate 6 was obtained in the same manner as in Example 5 except that the polarizer 2 was used in place of the polarizer 1. At this time, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of all the pressure-sensitive adhesive layers in the optical laminate 6 is 40 占 퐉, the thickness T2 of the polarizer is 12 占 퐉, 0.30.

[Example 7]

An optical laminate 7 was obtained in the same manner as in Example 5 except that the thickness of the second pressure-sensitive adhesive layer was changed to 40 탆. At this time, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of the pressure-sensitive adhesive layer in the optical laminate 7 is 60 占 퐉, the thickness T2 of the polarizer is 23 占 퐉, 0.38.

[Comparative Example 1]

An optical laminate 8 was obtained in the same manner as in Example 1 except that the polarizer 3 was used in place of the polarizer 1. At this time, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of all the pressure-sensitive adhesive layers in the optical laminate 8 is 40 占 퐉, the thickness T2 of the polarizer is 28 占 퐉, 0.70.

[Example 8]

An optical laminate 9 was obtained in the same manner as in Example 1 except that the polarizer 4 was used in place of the polarizer 1. In this case, the total thickness T1 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) of the pressure-sensitive adhesive layer in the optical laminate 9 is 40 占 퐉, the thickness T2 of the polarizer is 12 占 퐉, 0.30.

[Example 9]

An optical laminate 10 was obtained in the same manner as in Example 1 except that the polarizer 5 was used in place of the polarizer 1. At this time, the total thickness T1 of the pressure-sensitive adhesive layers in the optical laminate 10 (i.e., the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer) is 40 占 퐉, the thickness T2 of the polarizer is 12 占 퐉, 0.30.

[Referential Example 1]

An optical laminate 11 was obtained in the same manner as in Comparative Example 1, except that the second pressure-sensitive adhesive layer was not formed. T1 was 20 占 퐉, the thickness T2 of the polarizer was 28 占 퐉, and T2 / T1 was 1.40.

[Yellowing evaluation (105 占 폚)]

The optical laminate (1) to (10) obtained in Examples 1 to 9 and Comparative Example 1 were each cut into a size of 30 mm x 30 mm, and the surface of each of the first pressure-sensitive adhesive layer and the second pressure- ("EAGLE XG" manufactured by Corning Incorporated) to prepare an evaluation sample. Further, the optical laminate 11 obtained in Reference Example 1 was cut to a size of 30 mm x 30 mm, and the surface of the first pressure-sensitive adhesive layer was bonded to alkali-free glass ("EAGLE XG" manufactured by Corning Incorporated) Respectively.

The evaluation sample was subjected to an autoclave treatment for 1 hour at a temperature of 50 캜 and a pressure of 5 kg / cm 2 (490.3 kPa), and then left to stand for 24 hours under an environment of a temperature of 23 캜 and a relative humidity of 55%. Thereafter, a heating test was performed in which the sample was stored for 100 hours under a heating condition at a temperature of 105 DEG C, and the change in color before and after heating was visually confirmed. A that can hardly change was A, B that it was possible to confirm a slight change in color, C that it was possible to confirm the color change in half the area in the plane of the polarizing plate, and D that the color greatly changed in almost the entire inside of the plane of the polarizing plate . The obtained results are shown in Table 1.

In the evaluation sample including the optical laminate 11 prepared in Reference Example 1, since no alkali glass was laminated on only one side, no color change occurred because no polyenes were formed, and the evaluation result was A.

[Yellowing evaluation (95 占 폚)]

Evaluation samples were prepared by using the optical laminate (1) to (10) obtained in Examples 1 to 9 and Comparative Example 1 and Reference Example 1 in the same manner as described above. The evaluation sample was subjected to an autoclave treatment for 1 hour at a temperature of 50 占 폚 and a pressure of 5 kg / cm2 (490.3 kPa), and then left for 24 hours under an environment of a temperature of 23 占 폚 and a relative humidity of 55%. Thereafter, a heating test was performed in which the sample was stored for 100 hours under a heating condition at a temperature of 95 캜, and the change in color before and after heating was visually confirmed. A that can hardly change was A, B that it was possible to confirm a slight change in color, C that it was possible to confirm the color change in half the area in the plane of the polarizing plate, and D that the color greatly changed in almost the entire inside of the plane of the polarizing plate . The obtained results are shown in Table 1.

In the evaluation sample including the optical laminate 11 prepared in Reference Example 1, since no alkali glass was laminated on only one side, no color change occurred because no polyenes occurred, and the evaluation result was A.

[Moderate Evaluation]

The optical laminate (1) to (10) obtained in Examples 1 to 9 and Comparative Example 1 were each cut into a size of 150 mm x 100 mm, and the surface of each of the first pressure-sensitive adhesive layer and the second pressure- ("EAGLE XG" manufactured by Corning Incorporated) to prepare an evaluation sample. Further, the optical laminate 11 obtained in Reference Example 1 was cut to a size of 30 mm x 30 mm, and the surface of the first pressure-sensitive adhesive layer was bonded to alkali-free glass ("EAGLE XG" manufactured by Corning Incorporated) Respectively.

Thereafter, a heating test was performed in which the evaluation sample was stored for 30 minutes under a heating environment at a temperature of 105 ° C, and the change in the red color in the state of orthogonal Nicols before and after heating was visually confirmed. A, which shows almost no change before and after heating, A that shows no red stain, A that can slightly confirm the drop of red after heating, C, which clearly shows red stain after heating, and a noticeable red stain after heating And D was determined to be. The obtained results are shown in Table 1.

In the optical laminate of Examples 1 to 9 in which the ratio (T2 / T1) of the thickness T2 of the polarizer and the total thickness T1 of the first and second pressure-sensitive adhesive layers is 0.6 or less and the thickness T2 of the polarizer is 23 占 퐉 or less, And yellowing after exposure was difficult. On the other hand, in the optical laminate of Comparative Example 1 in which T2 / T1 exceeded 0.6 and T2 exceeded 23 占 퐉, a color change was observed in the evaluation of yellowing at 95 占 폚, and in the evaluation of yellowing at 105 占 폚, It was found that the color was greatly changed at almost the entire surface of the substrate and exposed to a high temperature environment, thereby remarkably yellowing. In the optical laminate of Reference Example 1, in which the second pressure sensitive adhesive layer was not provided and only one side of the optical laminate was covered with a glass plate, no yellowing occurred after exposure under a high temperature environment.

1: polarizer 2: first pressure-sensitive adhesive layer 2: second pressure-sensitive adhesive layer 3: protective film 4: adhesive layer 5: protective sheet 6: transparent plate 7: image display cell 10:

Claims (5)

A first pressure-sensitive adhesive layer, a polarizing plate and a second pressure-sensitive adhesive layer in this order,
Wherein the polarizer comprises a polarizer having a thickness of 23 m or less, the polarizer is a polyvinyl alcohol-based resin film containing a dichroic dye,
Wherein the total thickness of the pressure-sensitive adhesive layers included in the optical laminate is T1 and the thickness of the polarizer is T2, T2 / T1 is 0.6 or less. The optical laminate according to claim 1, wherein the polarizer has an absorbance A ₇₀₀ at a wavelength of 700 nm of 5.5 or less. The optical laminate according to claim 1 or 2, wherein the optical laminate is used by being bonded between the transparent plate and the image display cell through the pressure-sensitive adhesive layer. The optical laminate according to any one of claims 1 to 3, wherein the polarizing plate comprises a protective film having a moisture permeability of 200 g / m 2 · 24 hours or more, which is laminated on at least one surface of the polarizer. An image display apparatus comprising the optical laminate according to any one of claims 1 to 4.

Images