TW201808641A - Optical laminate - Google Patents

Abstract

Provide is an optical laminate which is hardly yellowed over time and is excellent in yellowing suppression effect even when exposed to high temperature environment. An optical laminate comprises a first adhesive layer, a polarizing plate, and a second adhesive layer in this order, The polarizing plate comprises a polarizer and a protective film laminated on at least one surface of the polarizer via an active energy ray curable adhesive layer, wherein the polarizer is a polyvinyl alcoholic resin film containing a dichroic dye, When the total thickness of all the pressure-sensitive adhesive layers contained in the optical laminate is T1, and the thickness of the polarizer is T2, T2/T1 is 0.6 or less.

Description

Optical laminate

The present invention relates to an optical multilayer body and an image display device including the optical multilayer body. Specifically, the present invention relates to an optical laminate used for bonding between a transparent plate and an image display unit via an adhesive layer, and an image display device including the optical laminate.

In the past, optical laminates such as polarizing plates and elliptically polarizing plates were used for bonding liquid crystal displays, liquid crystal cells, organic EL elements, and other image display units, and transparent plates (front panels) through an adhesive layer. Devices or organic EL display devices. In recent years, in addition to portable devices such as mobile phones and tablet terminals, such image display devices can also be used as vehicle-mounted image display devices such as car navigation devices or parking monitors. Extremely extensive. Along with this, the optical laminated body is required to have higher durability in a more severe environment (for example, a high-temperature environment) than conventional ones. Therefore, a polarizing plate (patent for the purpose of ensuring the durability) has been proposed. Reference 1).

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-102353

An image display device constructed by bonding an optical laminated body using a polyvinyl alcohol-based resin film containing a dichroic pigment as a polarizer through an adhesive layer between an image display unit and a transparent plate, when exposed to a high temperature environment Due to the polyenelation of polyvinyl alcohol, the problem of yellowing may occur in the optical laminate. This yellowing may cause defects in the appearance of the optical laminate, and further, due to the progress of the yellowing, the optical characteristics of the optical laminate may be defective. Especially under the severe temperature environment exceeding 95 ° C (for example, 105 ° C, etc.), the progress of yellowing tends to become more pronounced. Therefore, an optical laminate having a high suppression effect on yellowing in these high-temperature environments is required. body.

Therefore, an object of the present invention is to provide an optical laminate that is less prone to yellowing formed over time, and has excellent yellowing suppression effects even when exposed to a high temperature environment.

The present inventors have carefully studied in order to solve the above-mentioned problems, and have completed the present invention.

That is, the present invention provides the following preferred aspects [1] to [7].

[1] An optical laminated body, which is an optical laminated body sequentially provided with a first adhesive layer, a polarizing plate, and a second adhesive layer, wherein the polarizing plate includes: a polarizer, and an active energy ray-hardened type A protective film laminated on at least one side of the polarizer, wherein the polarizer is a polyvinyl alcohol-based resin film containing a dichroic dye; and When the total thickness of all the 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 multilayer body according to the above [1], wherein the polarizer is an absorbance A ₇₀₀ having a wavelength of 700 nm of 5.5 or less.

[3] The optical laminated body according to [1] or [2] above, which is adhered between the transparent plate and the image display unit through the aforementioned adhesive layer and is used by the user.

[4] The optical laminate according to any one of the above [1] to [3], wherein a thickness of the polarizer is 30 μm or less.

[5] The optical laminated body according to any one of the above [1] to [4], wherein the polarizing plate includes a protective film laminated on both sides of the polarizer through an active energy ray-curable adhesive layer. One of the protective films is made of a cellulose polymer.

[6] The optical laminated body according to any one of the above [1] to [5], wherein the protective film laminated on at least one of the polarizers has a moisture permeability of 200 g / m ² ‧ for 24 hours or more.

[7] An image display device including the optical multilayer body according to any one of the above [1] to [6].

According to the present invention, it is possible to provide an optical laminate that is less prone to yellowing formed over time, and has excellent yellowing suppression effects even when exposed to a high temperature environment.

1‧‧‧ polarizer

2‧‧‧ the first adhesive layer

2’‧‧‧second adhesive layer

3‧‧‧ protective film

4‧‧‧ Adhesive layer

5‧‧‧ protection sheet

6‧‧‧ transparent board

7‧‧‧Image display unit

10‧‧‧ polarizing plate

FIG. 1 is a cross-sectional view showing the structure of an optical multilayer body according to an embodiment of the present invention.

Fig. 2 is a sectional view showing the structure of an image display device 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 herein, and various changes can be made without departing from the scope of the present invention.

An optical multilayer body according to an embodiment of the present invention (also referred to as an "optical multilayer body of the present invention") is sequentially provided with a first adhesive layer, a polarizing plate, and a second adhesive layer. The structure of one embodiment of the optical laminated body of the present invention will be described with reference to FIG. 1. The optical laminated body of the present invention has a first adhesive layer (2) in an area layer on one side of the polarizing plate (10). An area layer of the polarizing plate (10) opposite to the first adhesive layer (2) is formed by a second adhesive layer (2 '). In the optical multilayer body of the present invention, the surfaces of the first adhesive layer (2) and the second adhesive layer (2 ') opposite to the polarizing plate (10) may be separately attached to protect the adhesive layer. Peelable protective sheet (5). The protective sheet (5) is peeled off, the first adhesive layer (2) is attached to the image display unit (7), and the second adhesive layer (2 ') is attached to the transparent plate (6). An image display device (also referred to as an "image display device of the present invention") constitutes an embodiment of the present invention as shown in FIG. 2. In Fig. 2, the backlight and the like are omitted.

The polarizing plate (10) constituting the optical laminate of the present invention is provided with at least one surface of the polarizer (1) provided with an adhesive layer (4) Structure of the protective film (3). In one embodiment of the optical laminated body of the present invention, the optical laminated body of the present invention is provided with a protective film (3) on both sides of the polarizer (1) via the adhesive layer (4).

Hereinafter, each constituent member of the optical laminated body of the present invention will be described in detail.

[Optical laminated body]

In the optical multilayer body of the present invention, when the total thickness of all the adhesive layers constituting the optical multilayer body is T1, and when the thickness of the polarizer is T2, T2 / T1 is 0.6 or less, preferably 0.55 or less, and particularly preferably It is 0.5 or less, and particularly preferably 0.45 or less. When the value of T2 / T1 exceeds 0.6, it is difficult to suppress yellowing when exposed to a high-temperature environment (especially at a temperature exceeding 95 ° C, such as a temperature of 105 ° C or higher). The lower limit value of T2 / T1 in the optical laminate of the present invention is not particularly limited, and is, for example, 0.001 or more, preferably 0.005 or more, particularly preferably 0.008 or more, and more preferably 0.01 or more. The so-called "total thickness T1 of all the adhesive layers constituting the optical laminate" refers to the thicknesses of the first adhesive layer and the second adhesive layer, and the sum of the thicknesses of other adhesive layers if present. The "other adhesive layer" refers to an adhesive layer other than the first adhesive layer and the second adhesive layer that may be included in the optical laminate, and examples thereof include bonding an optical film or an optical layer described later to polarized light. The adhesive layer of the board, and the adhesive layer that can be used to attach the polarizer and the protective film. When the optical laminated body does not contain other adhesive layers, and only includes the first adhesive layer and the second adhesive layer as the adhesive layer, the total thickness T1 of all the adhesive layers constituting the optical laminated body is the first adhesive. The sum of the thickness of the layer and the thickness of the second adhesive layer.

In the present invention, it is important to control the ratio of the thickness of the polarizer to the total thickness of the adhesive layer within a predetermined range to obtain a yellowing suppression effect. That is, for example, even if the polarizers have the same thickness, it is difficult to obtain a sufficient yellowing suppression effect when the predetermined ratio is not satisfied in the relationship with the total thickness of the adhesive layer. Similarly, even if the total thickness of the adhesive layer is the same, when the relationship with the thickness of the polarizer does not satisfy the above-mentioned predetermined ratio, it is difficult to sufficiently suppress yellowing when exposed to a high-temperature environment.

In the optical multilayer body of the present invention, by controlling the ratio of the thickness of the polarizer and the total thickness of the adhesive layer to the above-mentioned predetermined range, it is possible to easily impart a high yellowing suppression effect to the optical multilayer body. The yellowing of the optical laminate is caused by the polyenelation of the polyvinyl alcohol of the polarizer, and the polyenelation tends to be promoted when the water content of the polarizing plate is large. Therefore, for example, although the method of controlling the amount of water contained in the polarizing plate can be adopted in order to suppress polyenelation, a drying step for controlling the amount of water in the polarizing plate must be performed. When the drying step is performed at high temperature and / or for a long time, When performed under conditions, the optical characteristics of the polarizing plate may decrease. In the present invention, since the yellowing can be suppressed by controlling the ratio of the thickness of the polarizer to the total thickness of the adhesive layer in the aforementioned predetermined range, a drying step for adjusting the moisture content of the polarizing plate is not required, which is not easy. Degradation of the optical characteristics of the polarizing plate occurs. In addition, a drying step is not required, and production can be performed easily and efficiently, and productivity can be improved. In addition, since the yellowing suppression effect can be imparted by controlling the thickness of the polarizer and the total thickness of the adhesive layer, the constituent components and / or composition of the polarizer or the protective film constituting the polarizer are not limited. A combination of polarizers or protective films of various configurations is used. So you can choose easily available materials Or cheap materials are also advantageous from the viewpoint of reducing production costs.

In the present invention, when the thickness ratio of the polarizer and the adhesive layer is in the aforementioned predetermined range, although the effect of suppressing yellowing formed over time can be obtained, when the thickness (T2) of the polarizer is 30 μm or less, Furthermore, a particularly excellent yellowing suppressing effect can be obtained. The thickness of the polarizing plate constituting the optical laminate of the present invention is preferably 30 μm or less, particularly preferably 28 μm or less, and more preferably 25 μm or less. The lower limit of the thickness of the polarizer is not particularly limited, but is usually 3 μm or more. When the thickness of the polarizer is 30 μm or less, and the relationship between the thickness of the polarizer and the total thickness of the adhesive layer is in a range of T2 / T1 of 0.6 or less, the optical laminate of the present invention can obtain particularly excellent yellowing suppression effects. In addition, since the thickness of the polarizer is reduced, the thickness of the required adhesive layer is also reduced, which is also advantageous from the viewpoint of reducing the thickness of the optical laminate.

[Polarizer]

The polarizing plate constituting the optical laminate of the present invention has a protective film on at least one surface of the polarizer through an active energy ray-curable adhesive layer.

<Polarizer>

A polarizer refers to 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 pigment. As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a saponified product of a polyvinyl acetate-based resin can be used. Polyvinyl acetate resins, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, include copolymers of vinyl acetate and other monomers copolymerizable with vinyl acetate (ethylene-vinyl acetate). Copolymers, etc.). Other monomers copolymerizable with vinyl acetate, such as Examples 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-based resin can be modified. For example, polyvinyl formaldehyde, polyvinyl acetal, and polyvinyl butyral modified by aldehydes can be used. The degree of polymerization of the polyvinyl alcohol-based resin is generally in the range of 1,000 to 10,000, and preferably in the range of 1500 to 5,000.

A film made of this polyvinyl alcohol-based resin can be used as a green sheet for a polarizing film. The method for forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a film can be formed by a generally known method. The thickness of the blank material film made of a polyvinyl alcohol-based resin is not particularly limited, and considering the ease of stretching, it is, for example, 10 to 150 μm, preferably 15 to 100 μm, and more preferably 20 to 80 μm.

The manufacture of polarizers is usually carried out by the steps of uniaxially stretching a polyvinyl alcohol resin film, by dyeing the polyvinyl alcohol resin film with a dichroic pigment, and adsorbing the dichroic pigment, and by using boric acid. A step of treating a polyvinyl alcohol-based resin film to which a dichroic pigment is adsorbed with an aqueous solution; and a step of washing with water after treating with a boric acid aqueous solution. By dyeing a polyvinyl alcohol-based resin film with a dichroic dye, the dichroic dye is contained in the polyvinyl alcohol-based resin film. When a polarizer is produced by this manufacturing 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 performed before the dyeing of the dichroic pigment, or simultaneously with the dyeing, or after the dyeing. When uniaxial stretching is performed after dyeing, the uniaxial stretching It is carried out before treatment or during boric acid treatment. Uniaxial stretching may also be performed in these plural stages. For uniaxial stretching, uniaxial stretching can be performed between rollers with different peripheral speeds, or hot rollers can be used for uniaxial stretching. In addition, uniaxial stretching may be dry stretching in the air, or wet stretching using a solvent in a state where the polyvinyl alcohol-based resin film is swollen. The stretching ratio is preferably 8 times or less, more preferably 7.5 times or less, and even more preferably 7 times or less from the viewpoint of suppressing the distortion of the polarizer. In addition, the stretching ratio is generally 4.5 times or more from the viewpoint of showing the function as a polarizer. By setting the draw ratio to the aforementioned range, it is possible to suppress deformation of the polarizer over time.

A method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye includes, for example, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic pigment, for example, iodine or a dichroic dye can be used. The dichroic dye includes, for example, a dichroic direct dye composed of a diazo compound such as C.I. DIRECT RED 39, and a dichroic direct dye composed of a compound such as trisazo or tetrasazo. Prior to the dyeing treatment, the polyvinyl alcohol-based resin film is preferably subjected to a treatment of immersion in water.

When iodine is used as a dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is generally used. The content of iodine in the aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. When using iodine as a dichroic pigment, the temperature of the aqueous solution used for dyeing is usually 20 to 40 ° C. In addition, the immersion time (dyeing time) in the aqueous solution is usually 20 to 1800. second.

Before immersing the polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide, the film may be immersed in water for swelling and easy dyeing. The temperature of the immersion treatment is usually 20 to 80 ° C, preferably 30 to 60 ° C, 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 immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye for dyeing is generally adopted. The content of the dichroic dye in the aqueous solution is usually about 1 × 10 ^-4 to 10 parts by mass, preferably about 1 × 10 ^-3 to 1 part by mass, and particularly preferably about 1 × per 100 parts by mass of water. 10 ^-3 to 1 × 10 ^-2 parts by mass. This 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 temperature of the aqueous dye solution used for dyeing is usually 20 to 80 ° C, and the immersion time (dyeing time) in the aqueous solution is usually 10 to 1800 seconds.

The boric acid treatment after the dichroic dye is dyed is usually performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid aqueous solution. The amount of boric acid in this boric acid aqueous solution is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. When using iodine as a dichroic dye, the boric acid aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid aqueous solution is usually about 0.1 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, and particularly preferably 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C, and particularly preferably 60 to 80 ° C.

After the boric acid treatment, the polyvinyl alcohol resin film is usually washed with water. The water washing treatment can be performed, for example, by immersing the polyvinyl alcohol-based resin film treated with boric acid in water. The temperature of the water in the water washing treatment is usually 5 to 40 ° C, and the immersion time is usually 1 to 120 seconds. After washing with water and applying a drying treatment, a polarizer can be obtained. The drying process can be performed using, for example, a hot-air dryer or a far-infrared heater. The temperature of the drying treatment is usually 30 to 100 ° C, preferably 40 to 95 ° C, and particularly preferably 50 to 90 ° C. The drying time is usually 40 to 600 seconds, preferably 50 to 600 seconds, and particularly preferably 60 to 600 seconds.

In this way, a polarizer can be obtained by uniaxially stretching a polyvinyl alcohol-based resin film, dyeing a dichroic dye, and performing a boric acid treatment.

The absorbance A ₇₀₀ of the polarizer thus obtained at a wavelength of 700 nm is preferably 5.5 or less, particularly preferably 5.0 or less, more preferably 4.5 or less, and particularly preferably 4.2 or less. The absorbance A ₇₀₀ is related to the content of the I ₅ complex in the polarizer. When the I ₅ complex is too much, I ₃ ^- or I ^- iodide ions are generated from the I ₅ complex in the endurance test. Will promote the polyenelation reaction. The absorbance A ₇₀₀ may be 3.0 or more, preferably 3.5 or more, and more preferably 3.7 or more. When the absorbance A _{700 is} too low, the relative amount is reduced by the loss of the I ₅ complex in the endurance test. Therefore, the absorption near the wavelength of 700 nm is insufficient, and the polarizer may be reddened. The absorbance A _{700 of the} polarizer can be controlled, for example, by adjusting the temperature of water in the water washing process when manufacturing the polarizer.

The absorbance A _{700 of the} polarizing plate can be measured using an absorbance meter such as an ultraviolet-visible spectrophotometer, and calculated from the following formula.

A ₇₀₀ = -log [{TD transmittance at a wavelength of 700nm (%)} / 100] using the absorption axis direction of the polarizer is parallel to the incident light polarization was measured as. In this formula, the "TD transmittance" refers to the transmittance when the direction of polarized light emitted from Glan-Thompsonson is orthogonal to the transmission axis of the polarizer. For example, the measurement can be performed using an integrating sphere spectrophotometer V7100 manufactured by Japan Spectroscopy Corporation.

<Protective film>

The polarizing plate constituting the optical multilayer body of the present invention has a structure in which a protective film (particularly, a transparent protective film) is provided on at least one area of the polarizer. The protective film is beneficial to prevent the shrinkage and expansion of the polarizer, and to prevent the deterioration of the polarizer due to temperature, humidity, ultraviolet rays, etc. Therefore, in the optical laminated body of the present invention, it is preferably on both sides of the polarizer The laminate has a protective film.

The material constituting the protective film is preferably one having excellent transparency, mechanical strength, thermal stability, isotropy, and the like. Examples include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and cellulose triacetate, and polymethyl methacrylate. Acrylic polymers such as esters, styrene polymers such as polystyrene or acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. In addition, polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers, ring-based or cyclic olefin-based polymers having a norbornene structure, vinyl chloride-based polymers, nylon, or aromatic polyfluorene Amine-based polymers, amine-based polymers, fluorene-based polymers, polyether fluorene-based polymers, polyetheretherketone-based polymers, polyphenylene sulfide-based polymers, vinyl alcohol-based polymers, The vinylidene chloride-based polymer, ethylene butyral-based polymer, aryl ester-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or a blend of the aforementioned polymers can also be cited as the constitution. Examples of polymers for protective films. The protective film can also be formed as a hardened layer made of a thermosetting or ultraviolet curing resin such as acrylic, urethane, urethane, epoxy, or silicone. Among them, those having a hydroxyl group reactive with an isocyanate-based crosslinking agent are preferred, and cellulose polymers are particularly preferred.

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

The surface of the protective film that is not adjacent to the polarizer may have a surface treatment layer, such as an optical layer such as a hard coat layer or an anti-reflection layer, an anti-stacking layer, or an anti-glare layer or a diffusion layer. These optical layers can be bonded to a protective film via an adhesive layer composed of an adhesive described later.

The hard coating layer is used for the purpose of preventing damage to the surface of the polarizing plate. For example, a hardened film having excellent hardness or smoothness properties, such as acrylic-based, polysilicone-based UV-curable resin, etc. Surface mode and so on. The anti-reflection layer is for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an anti-reflection film or the like that has been followed in the past. In addition, the anti-stacking layer is for the purpose of preventing adhesion to adjacent layers.

In addition, the anti-glare layer is designed to prevent external light from reflecting on the surface of the polarizing plate and prevent the polarizing plate from seeing through the light. For example, it can be formed by providing a fine uneven structure on the surface of the protective film by a roughening method according to a sandblasting method or an imprint processing method, or a method of blending transparent particles. The fine particles contained to form the fine uneven structure on the surface include, for example, silicon dioxide, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 50 μm. The inorganic fine particles that can be made of conductive materials, and the organic fine particles that are made of crosslinked or uncrosslinked polymers and the like are transparent fine particles. When the surface fine uneven structure is formed, the content of 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 uneven structure. The anti-glare layer can also serve as a diffusion layer (perspective enlargement function, etc.) for diffusing the polarizing plate through light and expanding the viewing angle.

The anti-reflection layer, the anti-stacking layer, the diffusion layer, or the anti-glare layer, etc. may be provided on the protective film and integrated, or may be separately provided from the protective film as another optical layer. These optical layers can be bonded to a protective film via an adhesive layer composed of an adhesive described later.

In the present invention, the protective film laminated on at least one of the polarizers preferably has 200 g / m ^{2 for} more than 24 hours, more preferably 400 g / m ^{2 for} more than 24 hours, and more preferably 600 g / m ^{2 for} 24 hours. Above the moisture permeability. When a protective film having a moisture permeability above the lower limit value is present on at least one side of the polarizer, the yellowing of the optical laminate of the present invention over time can be more effectively suppressed, and both sides of the polarizer can be effectively suppressed. It is more preferable to have a protective film having a moisture permeability of the above lower limit value. Moisture permeability of the protective film is usually 2000g / m ² ‧24 hours or less. In the present invention, the moisture permeability means a value measured at a temperature of 40 ° C and a relative humidity of 90% in accordance with JIS Z0208: 1976.

<Adhesive layer>

In the optical multilayer body of the present invention, the polarizer and the protective film are attached via an active energy ray-curable adhesive layer. In the case of a dual-area layer protective film for a polarizer, it is preferable that any one of the protective films is bonded via an active energy ray-curable adhesive layer. Herein, in the present invention, the "active energy ray-curable adhesive layer" means a layer composed of a cured product of the active energy ray-curable adhesive layer, and the so-called "active energy ray-curable adhesive layer" means Adhesive hardened by irradiation with active energy rays. In the present invention, when the polarizing plate is provided with a protective film on both sides of the polarizer, the adhesive applied to one surface of the polarizer and the adhesive applied to the other surface of the polarizer may be the same or Different.

Conventionally, in most optical laminates, a water-based adhesive containing a polyvinyl alcohol-based resin or a urethane resin as a main component is used as an adhesive for bonding a polarizer and a protective film. The optical laminate of the present invention can effectively suppress yellowing of the optical laminate by using an active energy ray-curable adhesive as an adhesive for adhering a polarizer and a protective film. For example, by using an active energy ray-curable adhesive to bond the polarizer and the protective film, high yellowing suppression can be maintained even at a high temperature (for example, 105 ° C or higher) where a significant difference in yellowing is likely to occur, for example, higher than 95 ° C. effect. In addition, for example, in an optical laminated body including polarizing plates having the same thickness as that of a polarizer, compared with a case where a water-based adhesive is used to adhere to a protective film, when an active energy ray-curable adhesive is used to adhere to a protective film, The thickness of the adhesive layer required for the degree of yellowing suppression effect is small. That is, by using an active energy ray-curable adhesive, the thickness of the adhesive layer laminated on the polarizing plate can be made smaller, which is advantageous from the viewpoint of thinning the optical laminated body. In addition, by using an active energy ray-curable adhesive, a substantially solvent-free adhesive can be formed, so that the step of drying the adhesive layer is not required, and productivity can be improved.

When the active energy ray-curable adhesive is classified by its hardening pattern, a cationic polymerizable adhesive containing a cationic polymerizable compound as a hardenable compound, and a radical polymerizable polymer containing a radical polymerizable compound as a hardenable compound can be cited. Adhesive, and a mixed type curable adhesive containing both a cationically polymerizable compound and a radically polymerizable compound. Specific examples of the cationically polymerizable compound include epoxy compounds having one or more epoxy groups in the molecule, oxo compounds having one or more oxetane rings in the molecule, and ethylene compounds. Specific examples of the radical polymerizable compound include a (meth) acrylic compound and an ethylene compound having one or more (meth) acrylfluorenyl groups in the molecule. The active energy ray-curable adhesive may contain one or more cationically polymerizable compounds and / or one or two or more radically polymerizable compounds.

Cationic polymerization adhesive

The cationically polymerizable compound whose main component is a cationically polymerizable adhesive means a compound or oligomer that hardens by the irradiation or heating of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays to cause the cation polymerization reaction to proceed Examples of the substance include epoxy compounds, oxygen compounds, and ethylene Compounds etc. Among these, a preferable cationically polymerizable compound is an epoxy compound.

The epoxy compound is a compound having one or more epoxy groups, preferably two or more epoxy groups in the molecule. The epoxy compound may be used alone or in combination of two or more. Examples of the epoxy compound include an alicyclic epoxy compound, an aromatic epoxy compound, a hydrogenated epoxy compound, and an aliphatic epoxy compound. Among these, from the viewpoints of weather resistance, hardening speed, and adhesiveness, the epoxy compound preferably contains an alicyclic epoxy compound or an aliphatic epoxy compound, and particularly preferably contains an alicyclic epoxy compound.

An alicyclic epoxy compound is a compound having one or more epoxy groups bonded to an alicyclic ring in the molecule. The "epoxy group bonded to an alicyclic ring" means an oxygen atom -O- bridged in the structure represented by the following formula (I). In the following formula (I), m is an integer of 2 to 5.

In (CH ₂ ) _m of the above formula (I), a compound in which one or more hydrogen atoms are bonded to other chemical structures may be alicyclic epoxy compounds. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group.

Among them, an alicyclic epoxy compound having epoxycyclopentane [one of m = 3 in the above formula (I)] or epoxycyclohexane [one of m = 4 in the above formula (I)] is advantageous for improving The storage elastic modulus of the adhesive layer is also advantageous in terms of adhesion between the polarizer and the protective film. The following series reveal alicyclics Specific examples of formula epoxy compounds. Here, the names of the compounds are listed first, and then the corresponding chemical formulas are displayed. For the compound names and the corresponding chemical formulas, the same symbols are added.

A: 3,4-epoxycyclohexanecarboxylic acid 3,4-epoxycyclohexylmethyl ester, B: 3,4-epoxy-6-methylcyclohexanecarboxylic acid 3,4-epoxy -6-methylcyclohexylmethyl ester, C: bis (3,4-epoxycyclohexanecarboxylic acid ester) ethyl acetate, D: adipate bis (3,4-epoxycyclohexylmethyl) ) Ester, E: bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, F: diethylene glycol bis (3,4-epoxycyclohexylmethyl ether) , G: ethylene glycol bis (3,4-epoxycyclohexylmethyl ether), H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro [5.2.2.5.2.2] Icosane, I: 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane , J: 4-vinylcyclohexene dioxide, K: limonene dioxide, L: bis (2,3-epoxycyclopentyl) ether, M: dicyclopentadiene dioxide.

Aromatic epoxy compounds are compounds having an aromatic ring and an epoxy group in the molecule. Specific examples thereof include bisphenol-type epoxy compounds such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S or their oligomers; phenolic phenols Phenolic epoxy resins such as epoxy resin, cresol novolac epoxy resin, and hydroxybenzaldehyde phenolic novolac epoxy resin; glycidyl ether of 2,2 ', 4,4'-tetrahydroxydiphenylmethane, Polyfunctional epoxy compounds such as glycidyl ethers of 2,2 ', 4,4'-tetrahydroxydiphenyl ketone; polyfunctional epoxy resins such as epoxidized polyvinyl phenol.

The hydrogenated epoxy compound is a glycidyl ether of a polyhydric alcohol having an alicyclic ring. The aromatic polyhydric alcohol can be subjected to a selective hydrogenation reaction of the aromatic ring in the presence of a catalyst and under pressure to obtain a nuclear hydrogenated polyhydric alcohol. A hydroxy compound, and then the hydrogenated polyhydric hydroxyl compound is glycidyl etherified. Specific examples of the aromatic polyol include, for example, bisphenol A, Bisphenol compounds such as bisphenol F and bisphenol S; phenolic resins such as phenolic phenolic resins, cresol novolac resins and hydroxybenzaldehyde phenolic phenolic resins; tetrahydroxydiphenylmethane, tetrahydroxydibenzene Multifunctional compounds such as ketones and polyvinylphenol. An alicyclic polyol obtained by hydrogenating an aromatic ring of an aromatic polyol and reacting with epichlorohydrin can form a glycidyl ether. Among the hydrogenated epoxy compounds, preferred is a glycidyl ether of hydrogenated bisphenol A.

The aliphatic epoxy compound is a compound having at least one ethylene oxide ring (a three-membered cyclic ether) bonded to an aliphatic carbon atom in the molecule. Monofunctional epoxy compounds such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, etc .; 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl Difunctional epoxy compounds such as glycol diglycidyl ether; trifunctional or higher functional epoxy compounds such as trimethylolpropane triglycidyl ether, neopentyl tetraol tetraglycidyl ether; 4-vinyl ring dioxide Hexene, limonene dioxide and the like are epoxy compounds having one epoxy group directly bonded to an alicyclic ring and an ethylene oxide ring bonded to an aliphatic carbon atom. Among them, from the viewpoint of the adhesiveness between the polarizer and the protective film, a bifunctional epoxy compound (also known as an ethylene oxide ring having two aliphatic carbon atoms bonded in the molecule (also referred to as Is an aliphatic diepoxide). This preferable aliphatic diepoxy compound can be represented by the following formula (II), for example.

Y in the above formula (II) is an alkylene group having 2 to 9 carbon atoms, An alkylene group having a total carbon number of 4 to 9 having an ether bond interposed therebetween, or a divalent hydrocarbon group having 6 to 18 carbon numbers having an alicyclic structure.

The aliphatic diepoxy compound represented by the formula (II) is specifically a diglycidyl ether of an alkanediol, a diglycidyl ether of an oligomeric alkanediol having a repeating number of up to 4, or an alicyclic type Glycidyl ether of glycol.

Specific examples of the diol (glycol) which can form the aliphatic diepoxy compound represented by the formula (II) are disclosed below. Alkanediols are ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol , Neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2- Methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol , 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol and the like. Oligoalkanediols include diethylene glycol, triethylene glycol, tetraethylene glycol, and dipropylene glycol. Examples of the alicyclic diol include cyclohexanediol and cyclohexanedimethanol.

The oxo compound, which is one of the cationically polymerizable compounds, is a compound containing one or more oxo rings (oxo groups) in the molecule, and specific examples thereof include 3-ethyl-3-hydroxymethyloxo (also (Referred to as oxyfluorenol), 2-ethylhexyloxyfluorene, 1,4-bis [{(3-ethyloxyfluoren-3-yl) methoxy} methyl] benzene (also known as xylenedioxy呾), 3-ethyl-3 [{(3-ethyloxo-3-yl) methoxy} methyl] oxo, 3-ethyl-3- (phenoxymethyl) oxo, 3- (cyclohexyloxyoxy) methyl-3-ethyloxyphosphonium. The oxo compound can be used as a main component of the cationically polymerizable compound or in combination with an epoxy compound. By using an oxyphosphonium compound in combination, the curing speed or adhesion can be improved.

Ethylene compound capable of becoming a cationically polymerizable compound Examples of the substance include aliphatic or alicyclic vinyl ether compounds. Specific examples include n-pentyl vinyl ether, isoamyl vinyl ether, n-hexyl vinyl ether, and n-octyl vinyl ether. , 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, stearyl vinyl ether, etc. Ethers; hydroxyl-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether; cyclohexyl vinyl ether, 2-methylcyclohexyl ethylene Vinyl ethers of unit alcohols having aliphatic or aromatic rings, such as methyl ether, cyclohexyl methyl vinyl ether, benzyl vinyl ether; glycerol monovinyl ether, 1,4-butanediol monovinyl Ether, 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, neopentaerythritol divinyl ether, neopentaerythritol tetraethylene Ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane divinyl , 1,4-dihydroxymethylcyclohexane monovinyl ether, 1,4-dihydroxymethylcyclohexane divinyl ether, and the like, mono- to polyvinyl ethers of polyhydric alcohols; diethylene glycol divinyl Ether, triethylene glycol divinyl ether, diethylene glycol monobutyl monovinyl ether, and other polyalkylene glycol mono to divinyl ether; glycidyl vinyl ether, ethylene glycol vinyl ether methyl Other vinyl ethers such as acrylate. The ethylene compound can be used as a main component of the cationically polymerizable compound, or it can be used in combination with an epoxy compound, or an epoxy compound and an oxygen compound. By using an ethylene compound in combination, the hardening speed or viscosity of the adhesive can be increased.

The cation polymerization type adhesive may further include, for example, a cyclic lactone compound, a cyclic acetal compound, a cyclic thioether compound, and spirogen esterification. Cation polymerizable compounds other than the above.

From the viewpoint of the adhesiveness between the polarizer and the protective film, when the total amount of the curable compound contained in the cationically polymerizable adhesive (when a mixed type curable adhesive is included) is 100% by mass, cation polymerization The content of the active compound (the total content of the cationically polymerizable compound contained in the cationically polymerizable adhesive, when two or more kinds of cationically polymerizable compounds are contained, the total content thereof) is preferably 50% by mass or more, particularly It is preferably 60% by mass or more, and more preferably 70% by mass or more. The cationically polymerizable adhesive may further contain a polymer component (such as a thermoplastic resin). This can reduce the storage elastic modulus of the adhesive layer, or improve the adhesion between the polarizer and the protective film.

When the active energy ray-curable adhesive contains a cationically polymerizable compound, it is preferable to contain a photocationic polymerization initiator. The photocationic polymerization initiator is a person who generates a cationic substance or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and starts the polymerization reaction of the cation-hardening compound. Since the photocationic polymerization initiator uses light as a catalyst, it is excellent in storage stability and workability even when mixed with a photocationic curable compound. Examples of compounds that generate a cationic substance or a Lewis acid upon irradiation with active energy rays include aromatic onium salts or onium salts of aromatic sulfonium salts, aromatic diazonium salts, and iron-aromatic hydrocarbon complexes.

The aromatic sulfonium salt is a compound having a diarylsulfonium cation. Typically, the cation includes a diphenylsulfonium cation. An aromatic sulfonium salt is a compound having a triarylsulfonium cation, the cation, Typical examples include triphenylphosphonium cations and 4,4'-bis (diphenylphosphonium) diphenylsulfide cations. The aromatic diazonium salt is a compound having a diazonium cation. Typical examples of the cation include a benzenediazonium cation. The iron-arene complex is typically a cyclopentadienyl iron (II) arene cation complex salt.

The cations shown above are paired with anions (anions) to constitute a photocationic polymerization initiator. Examples include a photo-cationic polymerization initiator composed of anions, phosphorus-based special anion _{[(Rf) n PF 6-} n] -, hexafluorophosphate anion PF ₆ ^-, a hexafluoroantimonate anion SbF ₆ ^-, five hydroxy fluoro antimonate anion SbF ₅ (OH) ^-, hexafluoroarsenate anion AsF ₆ ^-, tetrafluoroborate anion BF ₄ ^-, tetrakis (pentafluorophenyl) borate anion _{B (C 6 F 5) 4} - , etc. . Among, the curable cationic polymerizable compound and then the resulting security perspective view of the adhesive layer, is preferably a phosphorus-based special anion _{[(Rf) n PF 6-} n] -, hexafluorophosphate anion PF ₆ ^-.

These photocationic polymerization initiators may be used alone or in combination of two or more. Among them, the aromatic sulfonium salt has ultraviolet absorption characteristics even in a wavelength region around 300 nm, so it has good hardenability and can provide a hardened material having good mechanical strength and adhesive strength, and can be preferably used.

The amount of the photocationic polymerization initiator in the active energy ray-curable adhesive is generally 0.5 to 10 parts by mass, and preferably 6 parts by mass or less, based on 100 parts by mass of the cationic polymerizable compound. By mixing the photocationic polymerization initiator to 0.5 parts by mass or more, the cationically polymerizable compound can be sufficiently hardened, and the obtained polarizing plate can be provided with a high level. Mechanical and adhesive strength. On the other hand, when the amount is too large, the ionic substance in the hardened material increases, the hygroscopicity of the hardened material increases, and the durability of the polarizing plate may be reduced.

As described above, in the cationically polymerizable adhesive agent, in addition to the cationically polymerizable compound, a mixed type adhesive agent may be constituted by containing a radically polymerizable compound. By using a radically polymerizable compound in combination, the effect of improving the hardness or mechanical strength of the adhesive layer can be expected, and the viscosity, curing speed, and the like of the adhesive can be adjusted more easily.

Radical Polymerization Adhesive

A radically polymerizable compound that is a main component of a radically polymerizable adhesive means a compound that is hardened by a radical polymerization reaction by irradiation or heating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Or oligomers, specifically, compounds having an ethylenically unsaturated bond. Examples of compounds having ethylenically unsaturated bonds include styrene, styrene sulfonic acid, and vinyl acetate, in addition to (meth) acrylic compounds having one or more (meth) acrylfluorenyl groups in the molecule. , Vinyl propionate, N-vinyl-2-pyrrolidone vinyl compounds, etc. Among them, a preferable radical polymerizable compound is a (meth) acrylic compound.

Examples of the (meth) acrylic compound include a (meth) acrylate monomer having at least one (meth) acryloxy group in the molecule, a (meth) acrylamide monomer, and 2 (Meth) acrylfluorene-containing compounds, such as (meth) acrylic acid oligomers, etc., obtained by reacting more than one functional group-containing compound and having at least two (meth) acrylfluorene groups in the molecule. (Meth) acrylic oligomer, preferably having at least 2 (meth) in the molecule (Meth) acrylate oligomers of acryloxy. The (meth) acrylic compound may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid ester monomer include a monofunctional (meth) acrylic acid ester monomer having one (meth) acryloxy group in the molecule and two (meth) acrylic acid in the molecule. A bifunctional (meth) acrylate monomer of a methoxy group, and a polyfunctional (meth) acrylate monomer having three or more (meth) acrylic fluorenyloxy groups in a molecule.

Examples of the monofunctional (meth) acrylate monomer are alkyl (meth) acrylates. In the alkyl (meth) acrylate, if the alkyl group has 3 or more carbon atoms, the alkyl group may be linear or branched. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, ( Isobutyl meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. In addition, such as aralkyl (meth) acrylates such as benzyl (meth) acrylate; (meth) acrylates of terpene alcohols such as isoamyl (meth) acrylate; such as tetrahydrofuran (meth) acrylate (Meth) acrylates with tetrahydrofuranmethyl structure of methyl esters; such as cyclohexyl (meth) acrylate, cyclohexyl methyl methacrylate, dicyclopentyl acrylate, dicyclopentene (meth) acrylate Esters, 1,4-cyclohexanedimethanol monoacrylates (meth) acrylates having a cycloalkyl group in the alkyl portion; such as N, N-dimethylamine ethyl (meth) acrylate Amine alkyl (meth) acrylate; such as 2-phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, ( (Meth) acrylic acid phenoxy polyethylene glycol esters (meth) acrylic acid esters having an ether bond at the alkyl portion can also be used as monofunctional (meth) acrylic acid ester monomers.

Furthermore, a monofunctional (meth) acrylate having a hydroxyl group at an alkyl moiety or a monofunctional (meth) acrylate having a carboxyl group at an alkyl moiety can also be used. Specific examples of the monofunctional (meth) acrylate having a hydroxyl group at the alkyl portion include 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, and (meth) 4-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, and neopentyltetraol mono (meth) acrylate. Specific examples of the monofunctional (meth) acrylate having a carboxyl group at the alkyl portion include 2-carboxyethyl (meth) acrylate and omega-carboxy-polycaprolactone (n ≒ 2) ), 1- [2- (meth) acryloxyethyl] phthalic acid, 1- [2- (meth) acryloxyethyl] hexahydrophthalic acid, 1- [2 -(Meth) acryloxyethyl] succinic acid, 4- [2- (meth) acryloxyethyl] trimellitic acid, N- (meth) acryloxy-N ', N'-Dicarboxymethyl-p-phenylenediamine.

The (meth) acrylamide monomer is preferably (meth) acrylamide having a substituent at the N-position. A typical example of the N-position substituent is an alkyl group, but it may also be substituted with (methyl) The nitrogen atoms of acrylamide form a ring together. This ring may have an oxygen atom as a ring constituent member in addition to the carbon atom and the nitrogen atom of (meth) acrylamide. Further, the carbon atoms constituting the ring may be bonded to a substituent such as an alkyl group or a pendant oxygen (= O) group.

Specific examples of N-substituted (meth) acrylamide include, for example, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, and N-isopropyl (meth) acryl Ammonium, N-n-butyl (meth) acrylamide, N-tertiary butyl (meth) acrylamide, N-alkyl (meth) acrylamine Ammonium; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acryl N, N-dialkyl (meth) acrylamide of fluoramines. The N-substituent may be an alkyl group having a hydroxyl group, and examples thereof include N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, and N- (2-hydroxypropyl) (meth) acrylamide and the like. Further, specific examples of the N-substituted (meth) acrylamide forming the 5- or 6-membered ring include N-acrylfluorenyl pyrrolidine, 3-propenyl-2-oxazolinone, 4-propenylmethylmorpholine, N-propenylmethylpiperidine, N-methacrylmethylpiperidine and the like.

Examples of the bifunctional (meth) acrylate monomers include alkanediol di (meth) acrylate, polyoxyalkylene dimethacrylate, and halogen-substituted alkane di (meth) acrylate. Glycol esters, di (meth) acrylates of aliphatic polyols, di (meth) acrylates of hydrogenated dicyclopentadiene or tricyclodecanedialkanol, dioxanediol or dioxanedi Di (meth) acrylate of alkanol, di (meth) acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, epoxy di (meth) acrylate of bisphenol A or bisphenol F Esters, etc.

More specific examples of the bifunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, and di (meth) 1,4-butanediol acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate Ester, trimethylolpropane di (meth) acrylate, neopentaerythritol di (meth) acrylate, di-trimethylolpropane di (meth) acrylate, diethyl di (meth) acrylate Glycol ester, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, di (meth) acrylate Polypropylene glycol (meth) acrylate, polytetramethylene glycol di (meth) acrylate, di (meth) acrylic acid Polysiloxane, di (meth) acrylate of neopentyl glycol trihydroxyacetate; 2,2-bis [4- (meth) propenyloxyethoxyethoxyphenyl] propane , 2,2-bis [4- (meth) propenylethoxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadiene di (meth) acrylate, tricyclic di (meth) acrylate Decane dimethanol ester, 1,3-dioxane-2,5-diyl di (meth) acrylate [alias: dioxanediol di (meth) acrylate], hydroxypivalaldehyde and tris Acetal compounds of methylolpropane [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] Di (meth) acrylate, tri (hydroxyethyl) trimeric isocyanate di (meth) acrylate, and the like.

Polyfunctional (meth) acrylate monomers with three or more functions. Representative examples include glyceryl tri (meth) acrylate, glyceryl tri (meth) acrylate, and trimethylolpropane tri (meth) acrylate. Ester, di-trimethylolpropane tri (meth) acrylate, di-trimethylolpropane tetra (meth) acrylate, neopentyltetraol tri (meth) acrylate, tetra (meth) acrylic acid Pentaerythritol, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Poly (meth) acrylates of aliphatic polyols, other examples include poly (meth) acrylates of tri- or higher-functional halogen-substituted polyols, and tris (meth) acrylic acid of glycerol alkylene oxide adducts. Esters, tris (meth) acrylates of alkylene oxide adducts of trimethylolpropane, 1,1,1-tris [(meth) acryloxyethoxyethoxyethoxy] propane, tris ( (Hydroxyethyl) trimeric isocyanate tri (meth) acrylate and the like.

On the other hand, (meth) acrylic oligomers include urethane (meth) acrylate oligomers, polyester (meth) acrylic oligomers, Epoxy (meth) acrylic oligomers and the like.

The urethane (meth) acrylate oligomer is a compound having a urethane bond (-NHCOO-) and at least two (meth) acrylfluorenyl groups in the molecule. Specifically, it may be a hydroxyl-containing (meth) acrylic monomer having at least one (meth) acryl group and at least one hydroxyl group in the molecule, and a urethane reaction product with polyisocyanate. Or a urethane compound containing an isocyanate group at the end obtained by reacting a polyol with a polyisocyanate, and a (methyl group) having at least one (meth) acrylfluorenyl group and at least one hydroxyl group in the molecule, respectively. ) Urethane reaction products of acrylic monomers and the like.

The hydroxyl-containing (meth) acrylic monomer used in the urethane reaction may be, for example, a hydroxyl-containing (meth) acrylate monomer, and specific examples thereof include 2-hydroxy (meth) acrylate Ethyl ester, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glyceryl di (meth) acrylate , Trimethylolpropyl di (meth) acrylate, neopentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate. Specific examples other than the hydroxyl-containing (meth) acrylate monomer include N-hydroxyalkyl (such as N-hydroxyethyl (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, etc.) Methacrylamide monomer.

Polyisocyanates that provide urethane reaction with hydroxyl-containing (meth) acrylic monomers, including hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, and dicyclohexylmethane di Isocyanate, toluene diisocyanate, xylene diisocyanate, and the aromatic isocyanates in these diisocyanates are hydrogenated To diisocyanates (e.g., hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, etc.), triphenylmethane triisocyanate, dibenzylbenzene triisocyanate, and the like, or di- or tri-isocyanate, and the above-mentioned diisocyanate is polymerized The obtained polyisocyanate and the like.

In addition, in addition to aromatic, aliphatic, or alicyclic polyols, polyesters that can be used to form urethane compounds containing isocyanate groups at the end by reaction with polyisocyanates can also be polyesters. Polyols, polyether polyols, and the like. Examples of the aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, Trimethylolethane, trimethylolpropane, di-trimethylolpropane, neopentaerythritol, dinepentaerythritol, dimethylol heptane, dimethylolpropanoic acid, dimethylol Butyric acid, glycerol, hydrogenated bisphenol A, etc.

The polyester polyol is obtained by the dehydration condensation reaction of the above-mentioned polyol and a polycarboxylic acid or an anhydride thereof. Examples of polybasic carboxylic acids or their anhydrides are shown by adding "(anhydride)" to those who can become anhydrides, which are succinic acid (anhydride), adipic acid (anhydride), maleic acid (anhydride), and Ikon Acid (anhydride), trimellitic acid (anhydride), pyromelic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, hexahydrophthalic acid (anhydride), and the like.

In addition to polyalkylene glycols, polyether polyols may be polyoxyalkylene modified polyols obtained by reacting the above-mentioned polyols or dihydroxybenzenes with alkylene oxides.

A polyester (meth) acrylic oligomer is a compound having an ester bond in the molecule and at least two (meth) acrylfluorenyl groups (typically (meth) acrylfluorenyloxy). Specifically, (meth) acrylic acid and polycarboxylic acid can be used. Or its anhydride and a polyhydric alcohol obtained by dehydration condensation reaction. Examples of the polycarboxylic acid or its anhydride used in the dehydration condensation reaction include "(anhydride)" for those who can be an anhydride, which are succinic acid (anhydride), adipic acid, and maleic acid (anhydride). , Iconic acid (anhydride), trimellitic acid (anhydride), pyromelic acid (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid Formic acid and so on. Examples of the polyhydric alcohol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and neopentyl glycol. , Trimethylolethane, trimethylolpropane, di-trimethylolpropane, neopentaerythritol, dinepentaerythritol, dimethylol heptane, dimethylolpropionic acid, dimethylol Butyric acid, glycerol, hydrogenated bisphenol A, etc.

The epoxy (meth) acrylic acid oligomer can be obtained, for example, by the addition reaction of polyglycidyl ether and (meth) acrylic acid, and has at least two (meth) acrylic acid groups in the molecule. Examples of the polyglycidyl ether used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A. Diglycidyl ether and so on.

When the active energy ray-curable adhesive contains a radical polymerizable compound, it is preferable to contain a photoradical polymerization initiator. The photo-radical polymerization initiator is a person who starts a polymerization reaction of a radical-hardening compound by irradiation with an active energy ray such as visible light, ultraviolet rays, X-rays, or electron beams. The photoradical polymerization initiator may be used alone or in combination of two or more.

Specific examples of the photo-radical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethylacetal, and 1- (4-isopropylphenyl) -2- Hydroxy-2-methylpropane-1-one, 2-methyl-1- [4- (methylthio) phenyl-2-morpholine propane-1-one, 2-hydroxy-2-methyl-1 -Acetophenone-based initiators such as phenylpropane-1-one; diphenylketones such as diphenylketone, 4-chlorodiphenylketone, 4,4'-diaminodiphenylketone, etc. Starters; benzoin ether-based initiators such as benzoin propyl ether, benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; others include xanthone, fluorenone, camphorquinone, Benzaldehyde, anthraquinone.

The blending amount of the photo-radical polymerization initiator in the active energy ray-curable adhesive is usually 0.5 to 20 parts by mass, and preferably 1 to 6 parts by mass based on 100 parts by mass of the radical polymerizable compound. By blending the photo radical polymerization initiator with 0.5 parts by mass or more, the radical polymerizable compound can be sufficiently hardened, and high mechanical strength and adhesion strength can be imparted to the obtained polarizing plate. On the other hand, when the amount is too large, the durability of the polarizing plate may be reduced.

In the present invention, the active energy ray-curable adhesive may contain, for example, an organic solvent in order to adjust the viscosity suitable for the coating method to be used, but it is preferably substantially solvent-free (solvent-free). By "substantially free", it is meant that the situation where the solvent is inevitably mixed in is not excluded. When a solvent is contained, the content of the solvent is preferably 10% by mass or less based on 100% by mass of the active energy ray-curable adhesive. By making the active energy ray-curable adhesive substantially free of a solvent, the polyenelation of the polyvinyl alcohol constituting the polarizer can be suppressed. In addition, since the step of drying the adhesive layer is not required, it can be improved. Productive.

Active energy ray hardening type adhesive, containing cationic polymerization accelerator, photosensitizer, ion trap, etc. Additives such as collectors, antioxidants, chain transfer agents, adhesion-imparting agents, thermoplastic resins, fillers, flow regulators, plasticizers, defoamers, antistatic agents, flattening agents, solvents, etc.

In the optical multilayer body of the present invention, the thickness (after hardening) of the adhesive layer formed of the active energy ray-curable adhesive is usually 0.001 to 10 μm, preferably 0.01 to 5 μm, and particularly preferably 0.01 to 3 μm, more It is preferably 0.02 to 2 μm. When the thickness of the adhesive layer is within the foregoing range, the adhesion between the polarizer and the protective film can be sufficiently ensured, and the appearance is also good, and it is also beneficial to the thinning of the polarizing plate. The body is better.

In the present invention, the active energy ray-curable adhesive layer may be, for example, coated on an polarizer or a protective film laminated on a polarizer, and coated with an active energy ray-curable adhesive or bonded with an active energy ray formed in advance into a film. A hardening type adhesive is formed by irradiating an active energy ray to harden the adhesive layer. As a method for applying the active energy ray-curable adhesive, a generally known method can be used. For example, a fluid casting method, a wire rod coating method, a gravure coating method, a comma wheel coating method, a doctor blade coating method, Die casting method, dip coating method, spray method and the like. The fluid casting method is a method in which a film to be coated is moved to a substantially vertical direction, a horizontal direction, or an oblique direction therebetween while the adhesive flows into the surface and spreads the coating. After the adhesive is applied, the polarizer and the protective film attached to the polarizer are overlapped, and sandwiched by a roller or the like to adhere the film. For bonding using a roll film, for example, a method of uniformly pressing and expanding by applying pressure with a roller or the like after applying the adhesive, and passing between the roller and the roller after applying the adhesive A method of pressurizing and pressing to expand. In this case, the material of the roller used may be metal or rubber. In addition, when the film is pressed and expanded by passing between a plurality of rollers, the plurality of rollers may be the same material or different materials.

Examples of the active energy ray include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, and electron beams. In the present invention, ultraviolet rays are preferably used. The source of the active energy ray is not particularly limited, and preferably it is an active energy ray having a light emission distribution below a wavelength of 400 nm. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, Chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp, etc.

The light irradiation intensity of the activation energy ray-curable adhesive can be appropriately determined according to the composition of the activation energy ray-curable adhesive, and is not particularly limited. The irradiation intensity of the wavelength region in which the activation of the polymerization initiator is effective, It is preferably from 0.1 to 6000 mW / cm ² , particularly preferably from 10 to 1000 mW / cm ² , and even more preferably from 20 to 500 mW / cm ² . When the irradiation intensity is within the aforementioned range, the reaction time can be ensured, and in addition, the yellowing of the epoxy resin caused by the heat radiated from the light source and the exothermic heat of the active energy ray-curable adhesive during curing can be suppressed. Deterioration of polarizers. The light irradiation time of the active energy ray-curable adhesive can be appropriately selected according to the active energy ray-curable adhesive to be hardened, and it is not particularly limited, but it is preferable to make the product of the above-mentioned irradiation intensity and irradiation time represents the accumulated light quantity becomes 10 to 10000mJ / cm ^2, particularly preferably 50 to 1000mJ / cm ^2, more preferably 80 to 500mJ / cm ² of the embodiment is set. When the accumulated light amount of the activation energy ray-curable adhesive is within the aforementioned range, the activated material from the polymerization initiator can be sufficiently generated, and the curing reaction can be performed more reliably. In addition, the irradiation time will not be excessively long and can be maintained. Good productivity.

The hardening of the active energy ray-curable adhesive by irradiation of the active energy ray, for example, does not prevent the polarization, transmittance, and hue of the polarizer, and the transparency of various films constituting the protective film and the optical layer The various functions of the polarizer are reduced.

A surface treatment such as a plasma treatment, a corona treatment, an ultraviolet irradiation treatment, a flame treatment, a saponification treatment, or the like may be appropriately applied to the adhesion surface of the polarizer and the protective film. The saponification treatment includes a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide.

In the optical laminated body of the present invention, the polarizing plate may be further laminated with an optical film or an optical layer such as a retardation film, a viewing angle compensation film, a brightness enhancement film, an anti-glare film, an anti-reflection film, and a light-condensing film. These optical films and optical layers can be bonded to a polarizing plate via an adhesive layer composed of an adhesive described later.

The retardation film is an optical film showing optical anisotropy. Examples of the retardation film include a birefringent film obtained by subjecting a polymer material to uniaxial or biaxial stretching, an alignment film of a liquid crystal polymer, and a film. Those supporting an alignment layer of a liquid crystal polymer. The stretching treatment can be performed by, for example, roll stretching, long-gap stretching, tenter stretching, or tubular stretching. The stretching ratio is generally 1.1 to 3 times when uniaxially stretched. The thickness of the retardation film is not particularly limited, but is generally 10 to 200 μm, and preferably 20 to 100 μm.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, and poly Carbonate, polyarylate, polyfluorene, polyethylene terephthalate, polyethylene naphthalate, polyether fluorene, polyphenylene sulfide, polyphenylene ether, polyallylfluorene, polyvinyl alcohol , Polyamide, polyimide, polyolefin, polyolefin with norbornene structure, polyvinyl chloride, cellulose polymer, or various binary and ternary copolymers, Copolymers, blends, etc. These polymer raw materials can be oriented (stretched film) by stretching or the like.

The liquid crystal polymer includes, for example, various polymers in which a linear atomic group (a lysogen) that imparts conjugate property to liquid crystal alignment is introduced into a main chain or a side chain of a polymer or a side chain. Specific examples of the main chain type liquid crystal polymer include, for example, a nematic alignment polyester liquid crystal polymer, a discotic polymer or Cholesterol polymer and so on. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as the main chain skeleton, and a polymer having a conjugated atomic group. The spacer portion, and the liquid crystal original portion composed of a cyclic compound unit substituted with a para-position imparting nematic alignment as a side chain. Such a liquid crystal polymer is, for example, an alignment treatment surface on which the surface of a film such as polyimide or polyvinyl alcohol formed on a glass plate is subjected to a rubbing treatment, or an oblique vapor deposition of silicon oxide, or the like. Then, the solution of the liquid crystal polymer is spread and heat-treated.

A retardation film, for example, can be used to compensate for various wavelength plates For the purpose of coloring or viewing angle caused by the birefringence of the liquid crystal layer, etc., if there is a retardation according to the purpose of use, those who can laminate two or more retardation films to control the optical characteristics of the retardation, etc.

The viewing angle compensation film is a film that can expand the viewing angle in a way that the screen is viewed more clearly when the screen of the liquid crystal display device is viewed from a slightly oblique direction with respect to the screen. The viewing angle compensation film includes, for example, an alignment film of a retardation film, a liquid crystal polymer, or an alignment layer that supports a liquid crystal polymer on a transparent substrate. Ordinary retardation films are polymer films with birefringence that are uniaxially stretched in the plane direction. In contrast, retardation films that are used as viewing angle compensation films are used: A biaxially stretched polymer film with birefringence, or a birefringent polymer film with oblique alignment that is uniaxially stretched in that direction and also stretched in the thickness direction to control the refractive index in the thickness direction Film-like biaxially stretched film. Examples of the oblique alignment film include a heat shrinkable film adhered to a polymer film, and a polymer film subjected to a stretching treatment and / or a shrinkage treatment under the action of a shrinkage force formed by heating, or a liquid crystal Polymer oblique alignment and so on. The raw material polymer of the retardation film can be the same as the polymer described in the previous retardation film, and can be appropriately selected and used: to prevent the coloration of the liquid crystal cell caused by the change of the viewing angle caused by the retardation, etc. Or for the purpose of expanding a good viewing angle.

In addition, from the viewpoint of achieving a wide viewing angle with good viewing properties, the alignment layer of the liquid crystal polymer is particularly suitable for supporting an optical difference formed by a tilted alignment layer of a discotic liquid crystal polymer with a cellulose triacetate film. Phase viewing angle compensation film.

[Adhesive layer]

In the optical laminated body of the present invention, the first adhesive layer and the second adhesive layer are laminated on the surface of the polarizing plate, respectively. The first adhesive layer and the second adhesive layer are composed of an adhesive. The adhesives constituting the first adhesive layer and the second adhesive layer may be the same or different.

In the present invention, the adhesive is constituted by containing a resin. The type of the resin contained in the adhesive is not particularly limited, and examples thereof include (meth) acrylic resin, silicone resin, urethane resin, and rubber. The adhesive may contain a single or a plurality of resins. From the viewpoint that the functionality can be easily imparted to the adhesive by selecting the type of the monomer introduced into the resin, the resin is preferably a (meth) acrylic resin (A). Examples of the (meth) acrylic resin (A) include a structural unit derived from a (meth) acrylic acid ester (hereinafter also referred to as "monomer (1)") as a main component, which is represented by the following formula (1): Polymer. In the present invention, the so-called "polymer having a structural unit derived from the monomer (1) as a main component" means that it preferably contains a polymer derived from the monomer (1) with respect to all structural units constituting the polymer. The structural unit is 40% by mass or more, particularly preferably 60% by mass or more, for example, 80% by mass or more. In this case, the total structural unit of the polymer generally contains 100% by mass or less, preferably 90% by mass or less Structural unit derived from monomer (1).

In the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group or an aralkyl group usually having a carbon number of 14 or less, preferably 10 or less, and usually 1 or more.

In one embodiment of the present invention, the (meth) acrylic resin (A) may contain other structural units in addition to the structural unit derived from the (meth) acrylic acid ester (monomer (1)). The structural unit of the polar functional group monomer is preferably a structural unit derived from a (meth) acrylic compound having a polar functional group. Examples of the polar functional group include a carboxyl group, a hydroxyl group, an amine group, and a heterocyclic group typified by an epoxy ring. Examples of the (meth) acrylic compound having a polar functional group include (meth) acrylic acid, 2- (dimethylamino) ethyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate , And glycidyl acrylate. The (meth) acrylic resin (A) may contain a structural unit derived from a monomer having no polar functional group other than the monomer (1). The structural unit (monomer) that can be preferably used includes a structural unit derived from a monomer having one olefinic double bond and at least one aromatic ring in the molecule, and is preferably derived from a (methyl group having an aromatic ring). ) Structural units of acrylic compounds. In this specification, (meth) acrylic acid means any of acrylic acid and methacrylic acid, and when it is called (meth) acrylate or the like, "(meth)" also has the same meaning.

In the monomer (1), R ² is an alkyl group. More specifically, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, n-octyl acrylate, and dodecyl acrylate can be exemplified. Linear alkyl acrylates; branched alkyl acrylates such as isobutyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; methyl methacrylate, ethyl methacrylate, and formazan Propyl acrylate, n-butyl methacrylate, n-octyl methacrylate, and lauryl methacrylate linear alkyl methacrylates; and isobutyl methacrylate, 2-ethyl methacrylate Branched alkyl methacrylates based on hexyl esters and isooctyl methacrylates.

Among these, n-butyl acrylate is preferable, and specifically, among all structural units (monomers) constituting the (meth) acrylic resin (A), n-butyl acrylate is preferably 50% by mass or more, and The requirements regarding the aforementioned monomer (1) are satisfied.

In the monomer (1), when R ² is an aralkyl group, specific examples include benzyl acrylate and benzyl methacrylate.

These monomers (1) can be used individually or in combination.

The hydrogen atom of the alkyl group or aralkyl group constituting R ² in the aforementioned formula (1) may be substituted by the 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 aforementioned formula (1) is substituted with a group -O- (C ₂ H ₄ O) _n -R ³ , n is preferably 0 or 1 to 4 Integer, particularly preferably 0, 1, or 2. In addition, R ³ is an alkyl group or an aryl group having a carbon number of 12 or less, and if the carbon number of the alkyl group is 3 or more, it may be a straight chain or a branch. Examples of aryl groups constituting R ^{3 are} listed. In addition to phenyl or naphthyl, there are phenyl and biphenyl (or phenyl) substituted with nucleoalkyl groups such as tolyl, xylyl, and ethylphenyl. Phenyl) and the like. R ^{3 is} particularly preferred for such aryl groups.

R ² in the formula (1) is an alkyl group or an aralkyl group and a hydrogen atom of the alkyl group or the aralkyl group of R ² is substituted by a group -O- (C ₂ H ₄ O) _n -R ³ (methyl ) Acrylate, specifically, 2-methoxyethyl acrylate, ethoxymethyl acrylate, 2-phenoxyethyl acrylate, 2- (2-phenoxyethoxy) ethyl acrylate, and 2- (o-phenylphenoxy) ethyl acrylates are alkoxyalkyl esters, aryloxyalkyl esters or aryloxyethoxyalkyl esters of acrylic acid; 2-methoxyethyl methacrylate, methyl Ethoxymethyl methacrylate, 2-phenoxyethyl methacrylate, 2- (2-phenoxyethoxy) ethyl methacrylate, and 2- (o-phenylphenoxy) methacrylate ) Ethyl alkoxyalkyl methacrylates, aryloxy alkyl esters, aryloxy ethoxy alkyl esters, and the like.

The (meth) acrylic resin (A) of the present invention may contain a structural unit derived from a monomer having no polar functional group other than the monomer (1). Examples of the monomer having no polar functional group other than the monomer (1) include (meth) acrylate monomers having an alicyclic structure in the molecule, styrene-based monomers, vinyl-based monomers, and A monomer having a plurality of (meth) acrylfluorenyl groups in the molecule.

Next, a (meth) acrylic acid ester monomer which has an alicyclic structure in a molecule is demonstrated. The alicyclic structure refers to a cyclic paraffin structure having a carbon number of usually 5 or more, preferably about 5 to 7. Specific examples of acrylate monomers having an alicyclic structure are isoamyl acrylate, cyclohexyl acrylate, dicyclopentyl acrylate, cyclododecyl acrylate, methyl cyclohexyl acrylate, and triacrylate Methyl cyclohexyl, tert-butyl cyclohexyl acrylate, α-ethoxy cyclohexyl acrylate, cyclohexyl phenyl acrylate and the like. In addition, specific examples of methacrylic acid ester monomers having an alicyclic structure are listed, which are isoamyl methacrylate, cyclohexyl methacrylate, dicyclopentyl methacrylate, and cyclododecyl methacrylate. Alkyl esters, methylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, tertiary butyl cyclohexyl methacrylate, cyclohexylphenyl methacrylate, and the like.

Examples of styrenic monomers except styrene In addition, there are methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, and hexyl. Alkyl styrenes of styrene, heptyl styrene, and octyl styrene; fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and halogenated styrene of iodostyrene; in addition, there are Nitrostyrene, ethenylstyrene, methoxystyrene, divinylbenzene, etc.

Examples of vinyl monomers are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl laurate fatty acid vinyl esters; vinyl chloride and vinyl bromide Kind of vinyl halide; vinylidene chloride; vinylidene halide; vinyl pyridine, vinyl pyrrolidone and vinyl carbazole nitrogen-containing aromatic ethylene; butadiene, isoprene and chloroprene Ethylene conjugated diene monomers; in addition, there are acrylonitrile and methacrylonitrile.

Examples of (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- ( 6-hydroxyhexyl) (meth) acrylamide, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (propoxymethyl) ( (Meth) acrylamide, N- (butoxymethyl) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N -Isopropyl (meth) acrylamide, N- (3-dimethylaminopropyl) (meth) acrylamide, N- (1,1-dimethyl-3-oxobutyl) ) (Meth) acrylamidonium, N- [2- (2-Pentoxy-1-imidazolidinyl) ethyl] (meth) acrylamido, 2-acrylamido-2-methyl- 1-propanesulfonic acid and the like.

Examples of monomers having a plurality of (meth) acrylfluorenyl groups in the molecule include 1,4-butanediol di (meth) acrylate and 1,6-hexanedi (meth) acrylate. Alcohol esters, 1,9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene di (meth) acrylate Alcohol esters and tripropylene glycol di (meth) acrylates have monomers with two (meth) acrylfluorene groups in the molecule; trimethylolpropane tri (meth) acrylates have in the molecule. Three (meth) acrylfluorenyl monomers and the like.

The monomer constituting the (meth) acrylic resin (A) may contain two or more kinds of (meth) acrylates represented by the above formula (1), and optionally a monomer having a polar functional group and / or A monomer having no polar functional group other than the monomer (1).

The resin contained in the adhesive is based on gel permeation chromatography (GPC: Gel Permeation Chromatography), and the weight average molecular weight Mw in standard polystyrene conversion is not particularly limited, but Mw is preferably between 500,000 and 2 million. Range, particularly preferably in the range of 500,000 to 1.8 million. When the weight average molecular weight in terms of standard polystyrene is 500,000 or more, the adhesion under high temperature and high humidity can be improved, and there is a possibility of floating or peeling between the transparent plate or the image display unit and the adhesive layer. The tendency to decrease and the reworkability also tends to improve. In addition, when the weight-average molecular weight is 2 million or less, even if the size of the protective film attached to the adhesive layer changes, the adhesive layer also follows the change in size, so the brightness and center of the peripheral portion of the liquid crystal cell Since there is no gap between the brightness of the parts, it is preferable to suppress white spots or color unevenness. By weight The molecular weight distribution represented by the ratio Mw / Mn of the number 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 adhesive can be produced by, for example, various generally known methods such as a solution polymerization method, an emulsion polymerization method, a block polymerization method, and a suspension polymerization method. In the production of the resin, a polymerization initiator can be used, and the amount of the polymerization initiator is about 0.001 to 5 parts by mass based on 100 parts by mass of the total of all the monomers used in the production of the resin.

As the polymerization initiator, a thermal polymerization initiator or a photopolymerization initiator can be used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane). Alkane-1-carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy) Valeronitrile), dimethyl-2,2'-azobis (dimethylpropionate), and 2,2'-azobis (2-hydroxymethylpropionitrile) azo compounds; Lauryl peroxide, tertiary butyl hydroperoxide, benzoylperoxide, tertiary butyl peroxybenzoate, cumene hydroperoxide, diisopropylperoxy dicarbonate, Propylperoxydicarbonate, tert-butylperoxyneodecanate, tert-butylperoxyvalerate, and peroxo (3,5,5-trimethylhexyl) Organic peroxides; potassium persulfate, ammonium persulfate, and inorganic peroxides such as hydrogen peroxide. In addition, a redox-based initiator in which a peroxide and a reducing agent are used in combination can also be used as a polymerization initiator.

The method for producing the (meth) acrylic resin (A) is preferably a solution polymerization method among the methods described above. List of solution polymerization methods Specific examples include a method of mixing a desired monomer and an organic solvent, adding a thermal polymerization initiator under a nitrogen environment, and stirring at about 40 to 90 ° C, preferably about 50 to 80 ° C, for 3 to 15 hours. In addition, in order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state of being dissolved in an organic solvent. Here, as the organic solvent, for example, aromatic hydrocarbons such as toluene or xylene; ethyl acetate or butyl acetate; aliphatic alcohols such as propanol or isopropanol; acetone or methylethyl Ketones and ketones of methyl isobutanone.

In the present invention, the adhesive constituting the adhesive layer may contain other additives in addition to the resin described above. Other additives include, for example, a cross-linking agent, a silane-based compound, a cross-linking catalyst, a weathering stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler, an organic acid, and an anti- Electrostatic agents, and organic acid metal salts.

In addition, it is also useful to formulate an active energy ray (such as ultraviolet) hardening compound into the adhesive, and then irradiate the ultraviolet ray to harden to form a harder adhesive layer after forming the adhesive layer.

The crosslinking agent that can be contained in the adhesive is a compound having at least two functional groups in the molecule that can be crosslinked with the resin contained in the adhesive. Specific examples include isocyanate-based compounds, epoxy-based compounds, metal chelate-based compounds, and aziridine-based compounds.

The isocyanate compound is a compound having at least two isocyanate groups (-NCO) in the molecule, and examples thereof include toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, and Hydroxylene diisocyanate, diphenylmethane diisocyanate Esters, hydrogenated diphenylmethane diisocyanates, naphthalene diisocyanates, triphenylmethane triisocyanates, and the like. In addition, adducts obtained by reacting glycerol or trimethylolpropane-based polyols with these isocyanate-based compounds, or by dimerizing or trimerizing isocyanate-based compounds may also become adhesion. Crosslinking agent used. You may mix and use 2 or more types of isocyanate-type compounds.

The epoxy-based compound is a compound having at least two epoxy groups in the molecule, and examples thereof include bisphenol A epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and glycerol. Diglycidyl ether, glycerol triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidyl aniline, N, N, N ', N '-Tetraglycidyl-xylylenediamine and the like. You may mix and use 2 or more types of epoxy compounds.

Examples of the metal chelate-based compounds include polyvalent valences of acetoacetone or acetoacetate in aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium Metal compounds.

The aziridine-based compound is a compound having at least two three-membered skeletons composed of one nitrogen atom and two carbon atoms called ethyleneimine in the molecule, and examples thereof include diphenyl groups. Methane-4,4'-bis (1-aziridinecarboxamide), toluene-2,4-bis (1-aziridinecarboxamide), triethylene melamine, isobutylfluorenylbis-1- (2 -Methylaziridine), tri-1-aziridinylphosphine oxide, hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane tri-β- Aziridinyl propionate, tetramethylolmethane tri-β-aziridinyl propionate, and the like.

Among these crosslinking agents, preferably used are: an adduct obtained by reacting an isocyanate compound, especially toluene diisocyanate with a polyol; a dimer of toluene diisocyanate, and a terpolymer of toluene diisocyanate Adduct obtained by reacting hexamethylene diisocyanate with a polyol; an addition obtained by reacting a dimer of hexamethylene diisocyanate, a terpolymer of hexamethylene diisocyanate, a toluene diisocyanate and a polyol Adducts obtained by reacting hydrogenated xylene diisocyanate with a polyol; isophorone diisocyanates and / or adducts obtained by reacting isophorone diisocyanate with a polyol; these Mixtures of isocyanate-based compounds and the like.

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

When the optical laminate of the present invention is bonded to a transparent plate (for example, a glass plate) via an adhesive, from the viewpoint of improving the adhesion with the glass substrate, the adhesive of the present invention preferably contains a silane-based compound. In particular, it is preferable that the resin before the crosslinking agent is contained contains a silane-based compound.

Examples of the silane-based compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (2-methoxyethoxy) silane, and 3-glycidoxypropyltrimethoxy Silane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxy Silane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethyl Silane, 3-glycidoxypropylethoxydimethylsilane, etc. Two or more silane-based compounds can be used.

Silane compounds can be in the form of polysiloxane oligomers. When a polysiloxane oligomer is represented as a (monomer)-(monomer) copolymer, the following is mentioned, for example.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and Mercaptopropyl-containing copolymers of 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymers; mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxy Silane copolymers, mercaptomethyltriethoxysilane-tetramethoxysilane copolymers, and mercaptomethyl-containing copolymers of mercaptomethyltriethoxysilane-tetraethoxysilane copolymers; 3-methacryl 醯Oxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyltriethoxysilane -Tetramethoxysilane, 3-methacryloxypropyltriethoxysilane-tetraethoxysilane, 3-methacryloxypropylmethyldimethoxysilane-tetramethoxy Silane copolymer, 3-methacryloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropylmethyldiethoxysilane-tetramethoxysilane Copolymers, and methacryloxypropyl-containing copolymers of 3-methacryloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers; 3-acryloxypropyl Trimethoxysilane-tetramethoxysilane copolymer, 3-propenyloxypropyltrimethoxysilane-tetraethoxysilane copolymer Compound, 3-propenyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-propenyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-propenyloxypropyl copolymer Methyldimethoxysilane-tetramethoxysilane copolymer, 3-propenyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-propyleneoxypropylmethyldiethoxysilane -Tetramethoxysilane copolymers, and 3-propenyloxypropylmethyldiethoxysilane-tetraethoxysilane-based copolymers containing acryloxypropyl groups; vinyltrimethoxysilane-tetramethoxysilane Methoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylformaldehyde Dimethoxysilane-tetramethoxysilane copolymer, vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyl Diethoxysilane-tetraethoxysilane copolymers and other vinyl-containing copolymers; these silane-based compounds are often liquid. The content of the silane-based compound in the adhesive is usually 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 adhesive.

The thickness of the first adhesive layer and the thickness of the second adhesive layer may be the same or different from each other. The thickness of the first adhesive layer and the thickness of the second adhesive layer, as explained previously, in the relationship with the thickness (T2) of the polarizer, as long as the total thickness of all the adhesive layers in the optical laminate T1 and T2 It is sufficient that the ratio (T2 / T1) is 0.6 or less, and they can be appropriately determined independently.

In one embodiment, the optical multilayer body of the present invention can The image display unit described below is bonded via a first adhesive layer, and the transparent plate described below is bonded via a second adhesive layer. At this time, the thickness of the second adhesive layer and the thickness of the first adhesive layer may be the same or different, and the thickness of the second adhesive layer may be thicker than the thickness of the first adhesive layer.

The thickness of the first adhesive layer (unit-side adhesive layer) is preferably 3 μm or more, particularly preferably 5 μm or more, and more preferably 10 μm or more from the viewpoint of suppressing yellowing of the optical laminate. From the viewpoint of thinning, etc., the thickness is preferably 30 μm or less, particularly preferably 27 μm or less, and more preferably 25 μm or less. In addition, the thickness of the second adhesive layer (adhesive layer on the transparent plate side) is preferably 20 μm or more, particularly preferably 30 μm or more, and more preferably 40 μm or more from the viewpoint of suppressing yellowing of the optical laminate. From the viewpoint of thinning the optical laminated body, etc., the thickness is preferably 300 μm or less, particularly preferably 280 μm or less, and more preferably 250 μm or less. When the optical laminate includes an adhesive layer (other adhesive layer) other than the first adhesive layer and the second adhesive layer, the other adhesive layers are from the viewpoint of suppressing yellowing of the optical laminate, etc. It is preferably 3 μm or more, particularly preferably 5 μm or more. From the viewpoint of thinning the optical laminate, etc., it is preferably 30 μm or less, and particularly preferably 25 μm or less.

In the optical multilayer body of the present invention, peelable protective sheets can be attached to the surfaces of the first adhesive layer and the second adhesive layer on the opposite sides to the polarizing plate, respectively. The protective sheet is a sheet used for the purpose of protecting the exposed surface of the adhesive layer from damage or contamination before bonding the optical laminated body to the image display unit or the transparent plate, and the protective sheet is peeled off, for example, separately Adhere the first adhesive layer to the image display unit, and attach the second adhesive The agent layer is bonded to the transparent plate, and can constitute the image display device of the present invention. That is, neither the first adhesive layer nor the second adhesive layer is assembled in the display device without being removed.

The material constituting the protective sheet is, for example, a thermoplastic resin, and examples thereof include polyolefin resins such as polyethylene resins and polypropylene resins; polyethylene terephthalate or polyethylene naphthalate. Polyester resin; polycarbonate resin; (meth) acrylic resin, etc.

The optical laminate of the present invention is used by being bonded between a transparent plate and an image display unit through the above-mentioned adhesive layer. The transparent plate is responsible for suppressing warping of the image display unit such as a liquid crystal cell or protecting the image display unit, and is, for example, a light-transmitting (preferably optically transparent) plate-like body. The transparent plate may have a single-layer structure or a multilayer structure. Transparent panels, sometimes called transparent front panels. Examples of the image display unit include a liquid crystal unit (element) and an organic EL unit (element).

The transparent plate, which is the outermost part of the final product containing the optical laminate of the present invention, is required to exhibit sufficient durability even when used outdoors or semi-outdoor. From this viewpoint, the transparent plate is preferably made of an inorganic material such as glass or tempered glass, and a polymer film having a Young's modulus of 2 GPa or more. Inorganic materials such as glass or tempered glass are particularly suitable for flexible display applications, and polymer films are preferred. Among them, polycarbonate resin (Young's modulus 2 to 3 GPa), acrylic resin (Young's mold) are particularly preferred. 3 to 4 GPa), polyfluorene imide resin (Young's modulus 3 to 5 GPa), and polyether fluorene resin (Young's modulus GPa).

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

(A) Color filter layer

(B) TFT layer

(C) Transparent electrode layer

(D) Decorative layer

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

The integration of the transparent plate, the polarizing plate, and the image display unit can be achieved by bonding through the above-mentioned adhesive layer, thereby providing an image display device (also referred to as "this" Invention image display device "). In this image display device, in order to eliminate reflection or scattering of light at the interface between the transparent plate and the polarizing plate to improve visibility, the refractive index of the adhesive is preferably close to or the same as that of the transparent plate. The image display device of the present invention can suppress the yellowing formed by the image display portion (display) over time, and can display a stable image display function for a long period of time.

The optical multilayer body and image display device of the present invention, except In addition to portable devices such as televisions, personal computers, mobile phones, and tablet terminals, it has a high suppression effect against yellowing in a high temperature environment and can display stable image display functions for a long period of time. It is particularly suitable for automotive applications that are easily exposed to more severe temperature environments. Automotive applications include, for example, image display devices such as car navigation devices, speed meters, air-conditioning touch panels, back-up displays, and rear displays.

[Example]

The following series of examples and comparative examples illustrate the present invention in more detail.

1. Production of polarizer (1)

The polyvinyl alcohol film with a thickness of 75 μm (average degree of polymerization is about 2400, saponification degree of 99.9 mol% or more) is subjected to a uniaxial stretching of about 5 times by dry stretching, and then immersed in a tensioned state at 60 After 1 minute of pure water at ℃, it was immersed in a 28 ° C aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 for 60 seconds. Then, it was immersed in an aqueous solution of 72 ° C at a weight ratio of 8.5 / 8.5 / 100 of potassium iodide / boric acid / water for 300 seconds. Then, it was washed with pure water at 26 ° C. for 20 seconds, and then dried at 65 ° C. for 60 seconds to obtain a 28 μm-thick polarizer (1) having an iodine adsorption alignment with a polyvinyl alcohol film. The absorbance A ₇₀₀ at a wavelength of 700 nm of the polarizer (1) was 4.0.

2. Production of polarizer (2)

The polyvinyl alcohol film with a thickness of 60 μm (average degree of polymerization is about 2400, saponification degree of 99.9 mol% or more) is subjected to about 5 times of longitudinal uniaxial stretching by dry stretching, and then immersed in a stretched state at 60 After 1 minute of pure water at ℃, it was immersed in a 28 ° C aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 for 60 seconds. Then, it was immersed in an aqueous solution of 72 ° C at a weight ratio of 8.5 / 8.5 / 100 of potassium iodide / boric acid / water for 300 seconds. Then, it was washed with pure water at 26 ° C. for 20 seconds, and then dried at 65 ° C. for 60 seconds to obtain a polarizer (2) having a thickness of 23 μm that is iodine-adsorbed and aligned with the polyvinyl alcohol film. The polarizer (2) has an absorbance A ₇₀₀ at a wavelength of 700 nm of 4.0.

3. Production of Polarizer (3)

A polarizer (3) having a thickness of 23 μm that is iodine-absorbed and aligned with a polyvinyl alcohol film was obtained in the same manner as in “Production of Polarizer (2)” except that the temperature of pure water during washing was changed to 21 ° C. The absorbance A ₇₀₀ at a wavelength of 700 nm of the polarizer (3) is 3.3.

4. Production of Polarizer (4)

A polarizer (4) having a thickness of 23 μm that is iodine-absorbed and aligned with the polyvinyl alcohol film was obtained in the same manner as in “Production of Polarizer (2)” except that the temperature of pure water during washing was changed to 34 ° C. The absorbance A ₇₀₀ at a wavelength of 700 nm of the polarizer (4) is 4.7.

5. Preparation of ultraviolet (activating energy ray) hardening type adhesive

80 parts of the following alicyclic epoxy resin (a1) and 20 parts of the aliphatic epoxy resin (a2) were mixed as a hardening component, and then 4.5 parts of a photocationic polymerization initiator was mixed as a solid component to prepare ultraviolet curing Type adhesive.

‧Acycloaliphatic epoxy resin (a1): 3,4-epoxycyclohexanecarboxylic acid 3,4-epoxycyclohexylmethyl ester: manufactured by Daicel Chemical Industries Co., Ltd. "Celloxide (registered trademark) 2021P"

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

‧Photocationic polymerization initiator: Triarylsulfonium salt type photocationic polymerization initiator: 50% propylene carbonate solution, "CPI-100P" manufactured by San Apro Co., Ltd.

6. Preparation of water-based adhesive

To 100 parts by mass of water, 3 parts by mass of carboxyl-modified polyvinyl alcohol [KL-318 manufactured by Kuraray Co., Ltd.] was dissolved to prepare a polyvinyl alcohol aqueous solution. Next, 1.5 parts by mass of a water-soluble polyamidopolyamine epoxy resin was added to 100 parts by mass of water in the solution ["Sumirez Resin 650 (30), solid content concentration 30% by weight" manufactured by Taoka Chemical Industry Co., Ltd.] ] To this aqueous solution and mixed to obtain an aqueous adhesive.

[Example 1]

The optical laminated body (1) was produced in the following manner.

Using a bar coater, the UV-curable adhesive prepared in 5. above was applied to a 40-μm-thick cellulose triacetate film (TAC: Triacetyl Cellulose) so that the film thickness after curing was about 2 μm [ Konica Minolta Opto Co., Ltd., trade name "KC4UA", moisture permeability 830g / m ² ‧ 24 hours]. A polarizing plate (1) is bonded to this coating surface. Next, one side of a norbornene-based resin [trade name "ZEONOR" manufactured by Zeon Japan Co., Ltd., moisture permeability 20 g / m ² ‧ 24 hours] was applied to a single side having a thickness of 23 μm without stretching, and used. The rod coater applied the above-mentioned corona discharge-treated surface so that the cured film thickness became about 2 μm. A polarizer (1) having the above-mentioned cellulose triacetate film bonded on one side was bonded to the coated surface with the polarizer side to produce a laminate. Using an ultraviolet irradiation device with a conveyor belt [the lamp uses a "D Lamp" manufactured by Fusion UV Systems], so that the accumulated light amount becomes 250 mJ / cm ² , ultraviolet rays are irradiated from the cellulose triacetate film side of the laminate, so that The UV-curable adhesive is hardened.

Then, using a bonding apparatus ["LPA3301" manufactured by Fujipla Co., Ltd.], an acrylic adhesive (manufacturing source: Lintec Co., Ltd., model: # 7) was applied to the side of the ZEONOR surface, thereby forming a 25 μm-thick An adhesive layer. In addition, using the bonding apparatus described above, an acrylic adhesive (manufacturing source: Lintec Co., Ltd., model: # 7) was applied to the TAC surface side, thereby forming a second adhesive layer having a thickness of 25 μm. Thereby, an optical laminated body (1) was obtained.

At this time, the total thickness of all the adhesive layers in the optical laminate (1) (that is, the total thickness of the first adhesive layer and the second adhesive layer) T1 is 50 μm, and the thickness T2 of the polarizer is 28 μm, T2 / T1 is 0.56.

[Example 2]

A polarizer (2) was used in place of the polarizer (1), and the thicknesses of the first adhesive layer and the second adhesive layer were set to 20 μm, respectively. Otherwise, the same operation as in Example 1 was performed to obtain an optical laminate. Body (2). At this time, the total thickness of all the adhesive layers in the optical laminate (2) (that is, the total thickness of the first adhesive layer and the second adhesive layer) T1 is 40 μm, and the thickness T2 of the polarizer is 23 μm, T2 / T1 is 0.58.

[Comparative Example 1]

An optical laminated body (3) was produced in the following manner.

The above-mentioned water-based adhesive was coated on both sides of the above-mentioned polarizer (1), and a laminating device ["LPA3301" manufactured by Fujipla Co., Ltd.] was used so that the corona-treated surface became a bonding surface with the polarizer. ], A 40 μm-thick cellulose triacetate film (TAC) [Konica Minolta Opto Co., Ltd.'s trade name "KC4UA"] after corona treatment on one side was bonded to one side of the polarizer (1) As a protective film, a norbornene resin [trade name "ZEONOR" manufactured by Zeon Japan Co., Ltd.] having a thickness of 23 [mu] m and unstretched after corona treatment was applied to one side (1) ) On the other side. After drying at 80 ° C for 5 minutes, it was aged at 40 ° C and 23% RH for 72 hours. After curing, an acrylic adhesive (manufacturing source: Lintec Co., Ltd., model: # 7) was applied to the ZEONOR surface by using the above bonding device, thereby forming a first adhesive layer having a thickness of 25 μm. In addition, using the bonding apparatus described above, an acrylic adhesive (manufacturing source: Lintec Co., Ltd., model: # 7) was applied to the TAC surface side, thereby forming a second adhesive layer having a thickness of 25 μm. Thereby, an optical laminated body (3) was obtained.

At this time, the total thickness of all the adhesive layers in the optical laminate (3) (that is, the total thickness of the first and second adhesive layers) T1 is 50 μm, and the thickness T2 of the polarizer is 28 μm, T2 / T1 is 0.56.

[Comparative Example 2]

An optical laminate (4) was obtained in the same manner as in Comparative Example 1 except that the thicknesses of the first adhesive layer and the second adhesive layer were set to 20 μm, respectively. At this time, the total thickness of all the adhesive layers in the optical laminate (4) (that is, the total thickness of the first and second adhesive layers) T1 is 40 μm, and the thickness T2 of the polarizer is 28 μm, T2 / T1 is 0.70.

[Example 3]

A polarizing plate (3) was used in place of the polarizing plate (2), and other operations were performed in the same manner as in Example 2 to obtain an optical laminate (5). At this time, the total thickness of all the adhesive layers in the optical laminate (5) (that is, the total thickness of the first and second adhesive layers) T1 is 40 μm, and the thickness T2 of the polarizer is 23 μm, T2 / T1 is 0.58.

[Example 4]

A polarizing plate (4) was used in place of the polarizing plate (2), and otherwise the same as Example 2 was used to obtain an optical laminate (6). At this time, the total thickness of all the adhesive layers in the optical multilayer body (6) (that is, the total thickness of the first adhesive layer and the second adhesive layer) T1 is 40 μm, and the thickness T2 of the polarizer is 23 μm, T2 / T1 is 0.58.

[Reference Example 1]

An optical laminated body (7) was obtained in the same manner as in Comparative Example 2 except that the second adhesive layer was not formed. At this time, all of the optical laminate (7) The total thickness of the adhesive layer (that is, the total thickness of the first adhesive layer and the second adhesive layer) T1 is 20 μm, the thickness of the polarizer T2 is 28 μm, and T2 / T1 is 1.40.

[Yellowing evaluation (105 ° C)]

The optical laminates (1) to (6) obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were cut to a size of 30 mm × 30 mm, respectively, and each of the first adhesive layer and the second adhesive layer was cut. The surface was bonded to an alkali-free glass [trade name "EAGLE XG", obtained from Corning Co., Ltd.] to prepare an evaluation sample. In addition, the optical multilayer body (7) obtained in Reference Example 1 was cut into a size of 30 mm × 30 mm, and the surface of the first adhesive layer was bonded to an alkali-free glass [trade name "EAGLE XG", from Corning Corporation. System acquisition "to make evaluation samples.

This evaluation sample was subjected to an autoclave treatment at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa) for 1 hour, and then left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. Then, a heating test was performed in a heating environment at a temperature of 105 ° C for 100 hours, and the color change before and after heating was visually confirmed. A with almost no change is A, B with slight color change is recognized, and C with color change is recognized at about half of the area of the polarizing plate surface, so that almost the entire front of the polarizing plate surface is confirmed to be large The color changer is D. The results obtained are shown in Table 1. The evaluation sample including the optical laminated body (7) produced in Reference Example 1 had no color change because the alkali-free glass was laminated on only one side, so there was no color change. The evaluation result was A.

[Yellowing evaluation (95 ° C)]

As in the above, the optical laminated bodies (1) to (7) obtained in Examples 1 to 4, Comparative Examples 1 and 2 and Reference Example 1 were used to prepare evaluation samples. This evaluation sample was subjected to an autoclave treatment at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa) for 1 hour, and then left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. Then, a heating test was performed in a heating environment at a temperature of 95 ° C for 100 hours, and the color change before and after heating was visually confirmed. A with almost no change is A, B with slight color change is recognized, and C with color change is recognized at about half of the area of the polarizing plate surface, so that almost the entire front of the polarizing plate surface is confirmed to be large The color changer is D. The results obtained are shown in Table 1. The evaluation sample including the optical laminated body (7) produced in Reference Example 1 had no color change because the alkali-free glass was laminated on only one side, so there was no color change. The evaluation result was A.

[Red Change Assessment]

The optical laminates (1) to (6) obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were cut to a size of 150 mm × 100 mm, respectively, and each of the first adhesive layer and the second adhesive layer was cut. The surface was bonded to an alkali-free glass [trade name "EAGLE XG", obtained from Corning Co., Ltd.] to prepare an evaluation sample. In addition, the optical multilayer body (7) obtained in Reference Example 1 was cut into a size of 30 mm × 30 mm, and the surface of the first adhesive layer was bonded to an alkali-free glass [trade name "EAGLE XG", from Corning Corporation. System acquisition "to make evaluation samples.

Then, the evaluation sample was subjected to a heating test stored in a heating environment at a temperature of 105 ° C for 30 minutes, and the change in the degree of red discoloration in the state of orthogonal polarization before and after heating was visually confirmed. A with little change and no redness before and after heating is A, and slightly reddish discoloration after heating is B, C is marked as a significant red discoloration upon heating, and D is marked as a significant red discoloration upon heating. The results obtained are shown in Table 1.

The ratio of the thickness T2 of the polarizer to the total thickness T1 of the first and second adhesive layers is 0.6 or less, and the polarizer and the protective film are bonded to the polarizer and the protective film by an active energy ray-curable adhesive layer in Examples 1 and 2. In the optical laminate, almost no yellowing occurred after exposure to a high temperature environment. On the other hand, although the thickness of the polarizer and the total thickness of the adhesive layer were the same as those of Example 1, the polarizer and the protective film were bonded to the optical laminated body of Comparative Example 1 through a water-based adhesive layer, but they were exposed to Yellowing occurs in a high temperature environment, and especially in the evaluation at 105 ° C, compared with the evaluation at 95 ° C, a larger color change occurs. Furthermore, the ratio of the thickness T2 of the polarizer to the total thickness T1 of the first and second adhesive layers exceeds 0.6, and the polarizer and the protective film are an optical laminated body of Comparative Example 2 with an aqueous adhesive layer followed by, Significant yellowing due to exposure to a high temperature environment of 105 ° C. this In addition, in the optical laminated body of Reference Example 1 which did not have a second adhesive layer and had only one side of the optical laminated body covered with a glass plate, yellowing hardly occurred after exposure to a high temperature environment.

1‧‧‧ polarizer

2‧‧‧ the first adhesive layer

2’‧‧‧second adhesive layer

3‧‧‧ protective film

4‧‧‧ Adhesive layer

5‧‧‧ protection sheet

10‧‧‧ polarizing plate

Claims (7)

An optical laminated body includes a first adhesive layer, a polarizing plate, and a second adhesive layer in this order. The polarizing plate includes a polarizer, and an active energy ray-curable adhesive layer is laminated on the polarized light. A protective film on at least one side of the sheet, the polarizer is a polyvinyl alcohol-based resin film containing a dichroic pigment; and the total thickness of all the adhesive layers included in the optical laminate is T1, and the polarized light is When the thickness of the sheet is T2, T2 / T1 is 0.6 or less. The optical multilayer body according to item 1 of the scope of the patent application, wherein the polarizer is an absorbance A ₇₀₀ having a wavelength of 700 nm of 5.5 or less. The optical laminated body according to item 1 or 2 of the scope of patent application, which is adhered between the transparent plate and the image display unit through the aforementioned adhesive layer and is used by the user. The optical laminate according to any one of claims 1 to 3, wherein the thickness of the polarizer is 30 μm or less. The optical laminate according to any one of claims 1 to 4, wherein the polarizing plate includes a protective film laminated on both sides of the polarizer through an active energy ray-curable adhesive layer, and the aforementioned protection One side of the film is made of a cellulose polymer. The scope of the patent 1 to 5 of the optical laminate according to any one, wherein the laminated on the polarizer protective film of at least one of having more than 200g / m ² ‧24 moisture permeability hours. An image display device includes the optical multilayer body according to any one of claims 1 to 6 of the scope of patent application.