KR101722778B1 - Polarizing plate and its production method, and liquid crystal display - Google Patents

Abstract

The present invention relates to a polarizing film (51) comprising a polarizing film (51) in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film, and a curing composition containing an active energy ray curable compound laminated on one side of the polarizing film And a second protective layer 53 including a thermoplastic resin film laminated on the other surface of the polarizing film 51 through an adhesive layer 54 and a polarizing plate A manufacturing method thereof, and a liquid crystal display device using the polarizing plate.

A polarizing plate, a liquid crystal display, a polyvinyl alcohol-based resin film, a polarizing film

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate, a polarizing plate, a method of manufacturing the polarizing plate, and a liquid crystal display device using the polarizing plate and the liquid crystal display.

The present invention relates to a polarizing plate, a polarizing plate preferably used for a liquid crystal display device of a transverse electric field (IPS) mode, a manufacturing method thereof, and a liquid crystal display device operating in a transverse electric field mode using the polarizing plate.

2. Description of the Related Art In recent years, a liquid crystal display (LCD) has been widely used as an information display device such as a cellular phone, a personal digital assistant (PDA), a personal computer or a television, Applications are rapidly increasing. With the development of liquid crystal display technology, liquid crystal display devices of various modes have been proposed, and the problem of the LCD as a response speed, a contrast, and a narrow viewing angle has been solved.

As one of countermeasures for viewing angle compensation, a liquid crystal cell which can essentially enlarge the viewing angle has been proposed. For example, there are an optically compensated bend (OCB) mode, a vertical alignment (VA) mode, and an in-plane switching (IPS) mode. Among them, the IPS mode is to change the alignment state of liquid crystal molecules in a transverse electric field which applies a voltage in a direction parallel to the substrate surface. In the IPS mode, the liquid crystal molecules are aligned in parallel with the substrate surface in the voltage unapplied state, but are oriented substantially in the same direction, not twisted as in the TN mode.

The principle of the IPS mode will be described with reference to Figs. 1 and 2. Fig. 2 is a schematic perspective view showing an example of a normal black in order to explain the principle of an IPS mode. Fig. 2 (A) is a view showing a state of a voltage unattended state , And (B) show the state at the time of voltage application. In Fig. 2, the layers are shown separated from each other for easy understanding. In FIG. 2B, reference numerals are attached only to parts that are different from those in FIG. 2A, and reference numerals are omitted for parts that are the same as in FIG. 2A in order to avoid difficulties in the drawing.

The liquid crystal cell 10, which is the center of the IPS mode liquid crystal display, is composed of upper and lower cell substrates 11 and 12 and a liquid crystal layer 14 sandwiched between these cell substrates. The liquid crystal molecules 15 constituting the liquid crystal layer 14 are aligned substantially parallel to the surfaces of the cell substrates 11 and 12. [ The front polarizer 20 and the back polarizer 30 are disposed on the upper and lower sides of the liquid crystal cell 10 and the light from the backlight 40 disposed on the outer side (back side) Only the linearly polarized light parallel to the transmission axis of the back-surface-side polarizing plate 30 between the liquid crystal cell 10 and the backlight 40 is incident on the liquid crystal cell 10. [ The polarizing plate usually includes a polarizing film and a protective film.

In the voltage unapplied state shown in Fig. 2 (A), the liquid crystal molecules 15 are parallel to the cell substrate surface and are oriented substantially in the same direction. In this example, the liquid crystal molecules 15 are oriented in a direction substantially parallel to the transmission axis 32 of the back-surface-side polarizing plate 30. On one of the cell substrates (the lower substrate in this example) 12, electrodes 13 and 13 are provided in parallel in parallel to each other. In this state, the linearly polarized light 16 transmitted through the rear-side polarizing plate 30 passes the liquid crystal layer 14 without causing a change in the polarized state as it is, and passes through the linearly polarized light 17 And passes through the cell substrate 11 on the upper side. The linearly polarized light 17 that has passed through the upper cell substrate 11 is incident on the transmission axis 32 of the back side polarizing plate 30 when the transmission axis 22 of the front side polarizing plate 20 disposed thereon is placed perpendicular to the transmission axis 32 of the back side polarizing plate 30 It can not pass through the front side polarizing plate 20, and a dark state is displayed.

On the other hand, as shown in Fig. 2 (B), when an electric field 18 indicated by a broken line is applied between the electrodes 13 and 13 arranged in parallel on the cell substrate, Side polarizer 30, and is turned off from the transmission axis 32 of the back-surface-side polarizer 30. As a result, the polarization state is changed while the linearly polarized light 16 incident on the liquid crystal cell 10 passes through the liquid crystal layer 14, and after passing through the liquid crystal layer 14, the elliptically polarized light 17 ' So that a component that can pass through the transmission axis 22 of the front-side polarizing plate 20 is generated, and thus a bright state is displayed.

2 shows that the transmission axis 32 of the back side polarizing plate 30 is arranged to be substantially parallel to the longitudinal axis of the liquid crystal molecules 15 and the transmission axis of the front side polarizing plate 20 and the back side polarizing plate 30 Side polarizing plate 20 and the rear-side polarizing plate 30 are arranged so that the transmission axis 22 of the front-side polarizing plate 20 is substantially parallel to the long axis of the liquid crystal molecules 15, The same result can be obtained. The liquid crystal molecules 15 can be arranged such that the long axis of the liquid crystal molecules 15 is substantially parallel to the transmission axis of either one of the polarizing plates. At this time, it is not necessary to strictly parallel the longitudinal axis direction of the liquid crystal molecules 15 with the transmission axis of either one of the polarizing plates. Rather, the liquid crystal molecules 15 are rotated in a constant direction when the electric field 18 is applied , It may be shifted to an angle of, for example, within 10 degrees. In addition, by arranging the transmission axes of the front-side polarizing plate 20 and the back-surface-side polarizing plate 30 so as to be orthogonal to each other, a so-called normal black display in which a black state is displayed when a voltage is not applied and a bright state is displayed when a voltage is applied However, if the transmission axes of the front-side polarizing plate 20 and the back-surface-side polarizing plate 30 are arranged in parallel, a so-called normal white is displayed in which a bright state is displayed when a voltage is not applied and a black state is displayed when a voltage is applied.

As described above, in the IPS mode, since the liquid crystal molecules are oriented parallel to the substrate surface and in the same direction, the viewing angle characteristics are superior to the other modes. However, in the triacetylcellulose film conventionally used as a protective film in the polarizing plate, the retardation R _e in the plane is usually about 5 nm and the retardation R _th in the film thickness direction is usually 50 nm. Therefore, There is a problem in that transmitted light causes birefringence and light leakage occurs at the time of black display.

In order to solve such a problem, for example, a transparent film having a small in-plane retardation R _e and a small retardation R _th in the film thickness direction is produced in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2006-18245) As a protective film in the above-mentioned semiconductor device.

On the other hand, in order to make the protective film thinner in the polarizing plate, for example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-245924) discloses a polarizing film comprising a polyvinyl alcohol- Discloses a technique for forming a protective film by coating an uncured epoxy composition on a substrate and curing the composition. However, as a polarizing plate using a cured product of the epoxy composition disclosed therein as a protective film, the durability is not sufficient, and for example, the shrinkage of the polarizing film under high temperature conditions can not be sufficiently suppressed, and as a polarizing plate having a size exceeding 15 inches There has been a problem that the polarizing film may be broken.

DISCLOSURE OF THE INVENTION <

An object of the present invention is to provide a polarizing plate having a small retardation R _e in the protective layer surface and a retardation R _th in the film thickness direction disposed on the side of the liquid crystal cell and having a thin and lightweight property and durability, And a method for producing the polarizing plate. Another object of the present invention is to provide a liquid crystal display device using such a polarizing plate, in particular, a liquid crystal display device operating in a transverse electric field mode.

The present invention relates to a polarizing film comprising a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film, a first protective layer made of a cured product of a curable composition laminated on one surface of the polarizing film and containing an active energy ray- And a second protective layer comprising a thermoplastic resin film laminated on the other surface of the polarizing film through an adhesive layer.

In the polarizing plate of the present invention, the curable composition used for forming the first protective layer preferably contains an epoxy-based compound having at least one epoxy group in the molecule as the active energy ray-curable compound, More preferably at least one epoxy group bonded to the alicyclic ring.

The curable composition may further comprise an oxetane-based compound as an active energy ray-curable compound. Further, the curable composition may further contain, as an active energy ray-curable compound, a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule.

The thickness of the first protective layer made of the cured product of the curable composition is preferably 0.1 to 10 mu m.

The second protective layer preferably comprises a cellulose acetate-based film. Further, the adhesive layer preferably comprises a cured product of a curable composition containing an active energy ray-curable compound.

The polarizing plate of the present invention may further comprise a pressure-sensitive adhesive layer laminated on a surface of the first protective layer opposite to the polarizing film side. The polarizing plate of the present invention is preferably used for a liquid crystal display device operating in a transverse electric field mode.

Further, the present invention is a polarizing plate of the present invention comprising a liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein at least one of the pair of polarizing plates is the polarizing plate of the present invention having the pressure sensitive adhesive layer, And a pair of polarizing plates disposed on both sides of the liquid crystal cell, wherein the pair of polarizing plates are all the polarizing plates of the present invention having the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer And a liquid crystal cell bonded to the liquid crystal cell.

The liquid crystal cell in the liquid crystal display of the present invention comprises two substrates and a liquid crystal cell sandwiched between the substrates and operating in a transverse electric field mode having a liquid crystal layer oriented substantially parallel to the substrate in a voltage- .

Further, according to the present invention, a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, and a polarizing film laminated on one side of the polarizing film and made of a cured product of a curable composition containing an active energy ray- 1 protective layer and a second protective layer comprising a thermoplastic resin film laminated on the other surface of the polarizing film through an adhesive layer, wherein a coating layer of the curable composition is provided on the surface of the substrate A coating layer joining step of joining a coating layer of the curable composition provided on one surface of the base material to one surface of the polarizing film and a coating layer joining step of bonding a second protective layer to the other surface of the polarizing film through an adhesive There is provided a polarizing plate manufacturing method comprising a bonding step, a curing step of curing the coating layer and the adhesive, and a substrate removing step of removing the substrate .

It is preferable that curing of the application layer and the adhesive in the curing process is performed simultaneously by irradiating the active energy ray on the substrate side.

The polarizing plate of the present invention comprises a first protective layer having a retardation R _e in the plane and a retardation R _th in the film thickness direction small. Therefore, when the polarizing plate of the present invention is applied to a liquid crystal display device so that the first protective layer thereof is on the side of the liquid crystal cell, light leakage can be effectively prevented. Further, since the thickness of the protective layer can be reduced as compared with a conventional triacetylcellulose (TAC) film or the like by making the first protective layer from a cured product of the curable composition, the thickness and weight of the polarizing plate can be reduced.

Further, according to the polarizing plate manufacturing method of the present invention, it is possible to manufacture the polarizing plate according to the present invention without providing a drying step, so that the manufacturing process can be simplified.

<Polarizer>

3 is a schematic cross-sectional view showing a preferred example of the polarizing plate according to the present invention. A polarizing plate 50 shown in Fig. 3 includes a polarizing film 51, a transparent first protective layer 52 laminated on one side of the polarizing film 51, and a transparent second protective layer 53 ). The first protective layer and the protective layer 52 are made of a cured product of a curable composition containing an active energy ray-curable compound. The second protective layer 53 includes a thermoplastic resin film and is bonded to the polarizing film 51 through the adhesive layer 54. [ The polarizing plate 50 is provided with a pressure sensitive adhesive layer 55 for bonding to the liquid crystal cell or the like on the outer side of the first protective layer 52, that is, on the side opposite to the polarizing film 51 side of the first protective layer 52 . In addition, the polarizing plate of the present invention may not have a pressure-sensitive adhesive layer. Hereinafter, the polarizing plate of the present invention will be described in detail.

(Polarizing film)

The polarizing film which functions as a polarizing plate has a dichroic dye adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol resin constituting the polarizing film is obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include a copolymer of vinyl acetate and other monomers copolymerizable with the vinyl acetate, as well as polyvinyl acetate, which is a homopolymer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers and the like. The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol resin may also be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 10,000.

Such a polyvinyl alcohol-based resin film is used as the original film of the polarizing film. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The thickness of the original film containing the polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 10 μm to 150 μm.

The polarizing film is produced by a process comprising uniaxially stretching a disc film made of a polyvinyl alcohol-based resin as described above, a process of dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, A step of treating the adsorbed polyvinyl alcohol based resin film with an aqueous solution of boric acid, and a step of washing with water after treatment with an aqueous solution of boric acid.

The uniaxial stretching may be carried out before or after the dyeing by the dichroic dye. Alternatively, the uniaxial stretching may be performed after the dyeing. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to perform uniaxial stretching in these plural steps. In the uniaxial stretching, the main yarn may be uniaxially stretched between different rolls, or may be uniaxially stretched using hot roll. Further, it may be dry stretching such as stretching in the atmosphere, or wet stretching in which stretching is performed in a state of being swollen with a solvent. The stretching magnification is usually about 4 to 8 times.

In order to dye a polyvinyl alcohol-based resin film with a dichroic dye, for example, a polyvinyl alcohol-based resin film can be dipped in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine, a dichroic dye and the like are used. It is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment with water before the dyeing treatment.

When iodine is used as the dichroism dye, a dyeing method is usually employed in which a polyvinyl alcohol resin film is immersed in an aqueous solution containing iodine and potassium iodide. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight based on 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 10 parts by weight based on 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 占 폚, and the immersion time (dyeing time) in this aqueous solution is usually about 30 to 300 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a dyeing method is usually employed in which a polyvinyl alcohol resin film is packed in an aqueous dye solution containing a water-soluble dichroic dye. The content of the dichroic dye in the dye aqueous solution is usually about 1 × 10 ^-3 to 1 × 10 ^-2 parts by weight based on 100 parts by weight of water. The dye aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dye aqueous solution is usually about 20 to 80 DEG C, and the immersion time (dyeing time) in the dye aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid. The content of boric acid in the aqueous solution containing boric acid is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight, based on 100 parts by weight of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is usually about 2 to 20 parts by weight, preferably about 5 to 15 parts by weight, based on 100 parts by weight of water. The immersing time in the aqueous solution containing boric acid is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 占 폚, and the immersion time is about 2 to 120 seconds. After washing with water, drying treatment is carried out to obtain a polarizing film. The drying treatment can be performed using a hot-air dryer or a far-infrared heater. The drying temperature is usually about 40 to 100 占 폚. The time for the drying treatment is usually about 120 to 600 seconds.

As described above, a polarizing film in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film can be produced. The thickness of the polarizing film may be about 5 to 40 mu m.

(Protective layer)

In the present invention, the first protective layer provided on one side of the polarizing film as described above is constituted of a cured product of a curable composition containing an active energy ray curable compound. The second protective layer provided on the other side of the polarizing film is composed of a thermoplastic resin film, and the thermoplastic resin film is bonded to the other side of the polarizing film through an adhesive layer. Hereinafter, the first protective layer and the second protective layer will be described in order. The curable composition is also referred to as a curable resin composition.

(1) First protective layer

The first protective layer provided on one side of the polarizing film is composed of a cured product of the curable composition containing the active energy ray-curable compound as described above. The active energy ray-curable compound means a compound that can be cured by irradiation with active energy rays (for example, ultraviolet rays, visible rays, electron rays, X-rays, etc.). The active energy ray-curable compound may be a cationic polymerizable compound or a radical polymerizable compound. Examples of the cationic polymerizable compound include an epoxy compound having at least one epoxy group in the molecule (hereinafter sometimes simply referred to as an &quot; epoxy compound &quot;), an oxetane compound having at least one oxetane ring in the molecule , Simply referred to as &quot; oxetane-based compound &quot;), and the like. Examples of the radical polymerizing compound include a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule (hereinafter, sometimes referred to simply as a "(meth) acrylic compound" have. Further, the "(meth) acryloyloxy group" means a methacryloyloxy group or an acryloyloxy group.

The cured product obtained by irradiating the active energy ray to the curable composition containing the active energy ray-curable compound is excellent in transparency, mechanical strength and thermal stability, and has a film (first protective layer) defined by the following formula (1) The in-plane retardation value R _e and the retardation R _th in the film thickness direction defined by the following formula (2) provide almost zero protective layer. Here, is almost zero, the R _e is in the range of 0≤R _e ≤20, 0≤R _e ≤15 and which is more preferred, and more preferably from 0≤R _e ≤10. Further, the near-zero field in the R _th, the range of │R _th │≤25, it is more preferable that the │R _th │≤23 and the more preferred, │R _th │≤20.

R _e = (n _x -n _y ) x d

R _th = _{[(n x + n y) /} 2-n z × d]

here,

n _x : refractive index in the in-plane slow axis direction of the film

n _y : refractive index in the in-plane fast axis direction of the film (direction orthogonal to the slow axis direction)

n _z : refractive index in the film thickness direction

d: thickness of film

When the polarizing plate is bonded to the liquid crystal cell on the side of the first protective layer by making the first protective layer from a cured product of a curable composition having a retardation value R _e in the film plane and a retardation value R _th in the thickness direction of the film substantially zero, It is possible to effectively prevent light leakage during black display in the obtained liquid crystal display device. Further, since the thickness of the protective layer can be reduced, it is possible to reduce the thickness and weight of the polarizing plate and the liquid crystal display device.

The haze value of the first protective layer is preferably 0.5% or less, more preferably 0.3% or less, and further preferably 0.1% or less, in view of the fact that the protective layer laminated on the polarizing film is optically transparent. If the haze value exceeds 0.5%, the light is scattered and the transmittance is lowered.

The curable composition preferably contains at least an epoxy compound as the active energy ray curable compound, and thus a protective layer exhibiting good adhesion to the polarizing film is obtained.

As the epoxy compound, an epoxy compound which does not contain an aromatic ring in the molecule is preferably used as a main component in terms of weatherability, refractive index, cationic polymerizability and the like. As such an epoxy compound which does not contain an aromatic ring in the molecule, a hydrogenated epoxy compound, an aliphatic epoxy compound, an alicyclic epoxy compound and the like can be exemplified.

The hydrogenated epoxy compound can be obtained by subjecting an aromatic epoxy compound to a hydrogenation reaction selectively under pressure in the presence of a catalyst. Examples of the aromatic epoxy compounds include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, and hydroxybenzaldehyde phenol novolac epoxy resin; A glycidyl ether of tetrahydroxydiphenylmethane, a glycidyl ether of tetrahydroxybenzophenone, and a polyfunctional epoxy resin such as an epoxidized polyvinyl phenol. Among them, glycidyl ether of a bisphenol A hydride is preferably used as the hydrogenated epoxy compound.

Examples of the aliphatic epoxy compounds include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. More specifically, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol (Ethylene oxide or propylene oxide) obtained by adding at least one alkylene oxide (ethylene oxide or propylene oxide) to an aliphatic polyhydric alcohol such as ethylene glycol, propylene glycol or glycerin, Polyglycidyl ether, and the like.

The alicyclic epoxy compound means an epoxy compound having at least one epoxy group bonded to an alicyclic ring. The "epoxy group bonded to the alicyclic ring" has a structure represented by the following formula: wherein m is an integer of 2 to 5.

Therefore, the alicyclic epoxy compound is a compound having at least one structure represented by the above formula in the molecule. More specifically, a compound in which one or more hydrogen-removed groups in (CH ₂ ) _m in the above formula is bonded to another chemical structure may be an alicyclic epoxy compound. (CH ₂ ) _m may be appropriately substituted with a straight chain alkyl group such as methyl group or ethyl group.

Of the above epoxy compounds, alicyclic epoxy compounds, that is, compounds in which at least one of the epoxy groups is bonded to an alicyclic ring are preferable, and oxabicyclohexane ring (in the above formula, m = 3) An epoxy compound having an oxabicycloheptane ring (in the above formula, m = 4) is more preferably used because it has a high modulus of elasticity of the cured product and is easy to obtain a protective layer excellent in adhesion with a polarizing film. Hereinafter, the structure of the alicyclic epoxy compound preferably used in the present invention is specifically exemplified, but the present invention is not limited thereto.

(a) epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (I):

(I)

(Wherein R ¹ and R ² represent, independently of each other, a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(b) epoxycyclohexanecarboxylates of an alkanediol represented by the following formula (II):

&Lt;

(Wherein R ³ and R ⁴ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20)

(c) epoxycyclohexylmethyl esters of dicarboxylic acids represented by the following formula (III):

(III)

(Wherein R ⁵ and R ⁶ are each independently a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms, and p is an integer of 2 to 20)

(d) epoxycyclohexyl methyl ethers of polyethylene glycol represented by the following formula (IV):

(IV)

(Wherein R ⁷ and R ⁸ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10)

(e) epoxycyclohexyl methyl ethers of alkane diols represented by the following formula (V):

(V)

(Wherein R ⁹ and R ¹⁰ independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and r represents an integer of 0 to 18)

(f) a diepoxy trispyro compound represented by the following formula (VI):

&Lt; Formula (VI)

(Wherein R &lt; ¹¹ &gt; and R &lt; ¹² &gt; independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(g) a diepoxy monospiro compound represented by the following formula (VII):

(VII)

(Wherein R ¹³ and R ¹⁴ represent, independently of each other, a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(h) vinylcyclohexene epoxides represented by the following formula (VIII):

&Lt; Formula (VIII)

(Wherein R ¹⁵ represents a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(i) epoxycyclopentyl ethers represented by the following general formula (IX):

<Formula IX>

(Wherein R ¹⁶ and R ¹⁷ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(j) diepoxy tricyclodecane represented by the following formula (X):

(X)

(Wherein R ¹⁸ represents a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

Among the above-exemplified alicyclic epoxy compounds, the following alicyclic epoxy compounds are preferably used for reasons such as being commercially available or their analogues being relatively easy to obtain.

(A) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid with (7-oxa-bicyclo [4.1.0] hept- Compound of R &lt; ¹ &gt; = R &lt; ² &gt; = H]

(B) An ester with 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept- Cargo [compound of the formula (I) in which R ¹ = 4-CH ₃ , R ³ = 4-CH ₃ ]

(C) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [compound of formula (II) wherein R ³ ═R ⁴ ═H, n = 2 ],

(D) (7-oxabicyclo [4.1.0] hept-3-yl) methanol and adipic acid [compound of formula III in which R ⁵ = R ⁶ = H, p = 4]

(E) (4- methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol in the adipic acid and the esterified product [the formula ^{III, R 5 = 4-CH} 3, R 6 = 4-CH ₃ , p = 4]

(F) (an ether of 7-oxabicyclo [4.1.0] hept-3-yl) methanol and 1,2-ethanediol [wherein R ⁹ = R ¹⁰ = H, r = 2 &Lt; / RTI &gt;

In the present invention, the epoxy compound may be used alone, or two or more epoxy compounds may be used in combination.

In the curable composition used for forming the first protective layer, the epoxy compound is preferably contained in a proportion of 30 to 100% by weight, more preferably 35 to 70% by weight of the total active energy ray-curable compound , More preferably from 40 to 60% by weight. When the content of the epoxy compound is small, the adhesion between the polarizing film and the first protective layer tends to be lowered.

The curable composition may contain an oxetane-based compound as an active energy ray-curable compound in addition to the epoxy compound. By adding the oxetane-based compound, the viscosity of the curable composition can be lowered and the curing rate can be increased.

The oxetane-based compound is a compound having at least one oxetane ring (4-membered ring ether) in the molecule, and examples thereof include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [ (3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- Hexyloxymethyl) oxetane, phenol novolac oxetane, and the like. These oxetane compounds can be easily obtained from commercial products, and examples thereof include "AARON oxetane OXT-101", "AARON oxetane OXT-121", "AARON oxetane OXT-211" Oxetane OXT-221 &quot; and &quot; AARON oxetane OXT-212 &quot; (all manufactured by Doago Kosai Co., Ltd.). The blending amount of the oxetane-based compound is not particularly limited, but is usually 30% by weight or less, preferably 10 to 25% by weight, of the total active energy ray-curable compound.

When the curable composition used for forming the first protective layer contains a cationic polymerizable compound such as an epoxy compound or an oxetane compound, a photo cationic polymerization initiator is usually incorporated in the curable composition thereof. When a photo cationic polymerization initiator is used, since it is possible to form a protective layer at room temperature, it is possible to form a first protective layer on the polarizing film with good adhesiveness by reducing the need to take account of heat resistance and distortion caused by swelling have. Further, since the photo cationic polymerization initiator acts catalytically by light, even when mixed with the curable composition, the storage stability and workability are excellent.

The cationic photopolymerization initiator generates a cationic species or a Lewis acid by irradiation with an active energy ray such as visible light, ultraviolet ray, X-ray or electron beam to initiate polymerization reaction of an epoxy compound and / or an oxetane compound. In the present invention, any type of photocationic polymerization initiation system may be used. Specific examples thereof include onium salts such as aromatic diazonium salts, aromatic iodonium salts and aromatic sulfonium salts, and iron-arene complexes. have.

Examples of the aromatic diazonium salt include benzene diazonium hexafluoroantimonate, benzene diazonium hexafluorophosphate, and benzene diazonium hexafluoroborate.

Examples of the aromatic iodonium salt include diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, di (4- Nonylphenyl) iodonium hexafluorophosphate, and the like.

The aromatic sulfonium salts include, for example, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4'-bis [di 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenylsulfide bis hexafluoroantimonate, 4,4'-bis [ Di (p-toluyl) sulfonium] -2-isopropylthioquinoxaline, bis (4-hydroxyphenyl) diphenylsulfide bishexafluorophosphate, (Pentafluorophenyl) borate, 4-phenylcarbonyl-4'-fluorophenylboronate, 7- [di (p- tolyl) sulfonio] -2-isopropylthioxanetetra Diphenylsulfone hexafluorophosphate, diphenylsulfone diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide (P-toluyl) sulfonium-diphenylsulfide tetrakis (pentafluorophenyl) borate, and the like can be used. .

Examples of the iron-arene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) -Tris (trifluoromethylsulfonyl) methanide, and the like.

These photo cationic polymerization initiators can be easily obtained from commercial products. For example, "Kayarad PCI-220", "Kayarad PCI-620" (manufactured by Nippon Kayaku Co., Ltd.) CI-5102 "(trade name, manufactured by ADEKA)," Adeka Optomer SP-150 "," Adeka Optomer SP-170 "(manufactured by Adeka Kabaido Co., DPI-101 "and" DPI-2064S "(all manufactured by Nihon Soda Co., Ltd.)," CIT-1370 "," CIT-1682 "," CIP- 102, "" DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI- , "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS-102" PI-2074 "(manufactured by Rhodia)," UVACURE 1590 "(manufactured by Daicel-Cytec Co., Ltd.), and the like.

These photo cationic polymerization initiators may be used alone or in combination of two or more. Of these, aromatic sulfonium salts are preferably used because they have ultraviolet ray absorption properties even in a wavelength region of 300 nm or more and are thus excellent in curability and can provide a cured product having good mechanical strength and good adhesion with a polarizing film .

The compounding amount of the photo cationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the total amount of the cationic polymerizable compound such as an epoxy compound or an oxetane compound. If the blending amount of the photo cationic polymerization initiator is too small, the curing becomes insufficient and the mechanical strength and adhesion between the protective layer and the polarizing film tend to be lowered. On the other hand, if the blending amount of the photo cationic polymerization initiator is too large, the amount of the ionic substance in the cured product increases, so that the hygroscopic property of the cured product increases, and the durability of the obtained polarizing plate may be lowered.

It is preferable that the curable composition used for forming the first protective layer contains a (meth) acrylic compound that is radically polymerized together with the epoxy compound or an epoxy compound and an oxetane compound. (Meth) acrylic compound is used in combination, it becomes possible to obtain a protective layer having high hardness, excellent mechanical strength, and high durability. Further, the viscosity and curing rate of the curable composition, the surface curability of the obtained protective layer, and the adhesion property with the polarizing film can be more easily adjusted.

The (meth) acrylic compound is a compound obtained by reacting two or more kinds of (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule or a compound having a functional group and having at least two (meth) (Meth) acryloyloxy group-containing compounds such as a (meth) acrylate oligomer having a silyloxy group and a dioleo group. These may be used alone or in combination of two or more. When two or more (meth) acrylate monomers are used in combination, two or more (meth) acrylate monomers may be used, or two or more (meth) acrylate oligomers may be used. One or more oligomers may be used in combination. Further, "(meth) acrylate" means acrylate or methacrylate.

Examples of the (meth) acrylate monomers include monofunctional (meth) acrylate monomers having one (meth) acryloyloxy group in the molecule, difunctional (meth) acryloyloxymethyl groups having two (meth) acryloyloxy groups in the molecule, Acrylate monomers having at least three (meth) acryloyloxy groups in the molecule, and polyfunctional (meth) acrylate monomers having at least three (meth) acryloyloxy groups in the molecule.

Specific examples of monofunctional (meth) acrylate monomers include tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, Butyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenoxyethyl (Meth) acrylate, pentaerythritol mono (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethylcarbitol Met) arc There may be mentioned acrylate and the like.

As the monofunctional (meth) acrylate monomer, a carboxyl group-containing (meth) acrylate monomer may also be used. Examples of the monofunctional (meth) acrylate monomer containing a carboxyl group include 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, carboxyethyl (meth) ) Acryloyloxyethyl succinic acid, N- (meth) acryloyloxy-N ', N'-dicarboxymethyl-p-phenylenediamine and 4- (meth) acryloyloxyethyltrimellitic acid. .

Examples of the bifunctional (meth) acrylate monomers include alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, (Meth) acrylates of di (meth) acrylates, hydrogenated dicyclopentadiene or tricyclodecanedialanol, di (meth) acrylates of dioxane glycol or dioxanedialanol, bisphenol A or bisphenol A Di (meth) acrylates of alkylene oxide adducts of bisphenol F, and epoxy di (meth) acrylates of bisphenol A or bisphenol F, but not limited thereto, and various ones can be used.

More specific examples of the bifunctional (meth) acrylate monomers include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) (Meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol propane di (meth) acrylate, pentaerythritol di (meth) acrylate, Acrylate, diethylene glycol di (meth) acrylate, ditrimethylol propane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (Meth) acrylate, poly (ethylene glycol) di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (Meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxy (meth) acrylate, (Meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,3-dioxane-2,5-diyl di (meth) acrylate, hydrogenated dicyclopentadienyl (2-hydroxy-1,1-dimethylethyl) -5-ethyl-hexanediol di (meth) acrylate, which is an acetal compound of hydroxypropylaldehyde and trimethylolpropane (trade name: dioxane glycol di Di (meth) acrylate and tris (hydroxyethyl) isocyanurate di (meth) acrylate of 5-hydroxymethyl-1,3-dioxane.

Examples of trifunctional or higher polyfunctional (meth) acrylate monomers include glycerin tri (meth) acrylate, trimethylol propane tri (meth) acrylate, ditrimethylol propane tri (meth) acrylate, ditrimethylol propane tetra Acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (Meth) acrylates of trifunctional or higher functional aliphatic polyols such as tri (meth) acrylate, poly (meth) acrylates of trifunctional or higher halogen substituted polyols, tri (meth) acrylates of alkylene oxide adducts of glycerin, Tri (meth) acrylate of an alkylene oxide adduct of trimethylolpropane, 1,1,1-tris [(meth) acrylate, ) Acryloyloxyethoxyethoxy] propane, and tris (hydroxyethyl) isocyanurate tri (meth) acrylates.

On the other hand, (meth) acrylate oligomers include urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers and epoxy (meth) acrylate oligomers.

Urethane (meth) acrylate oligomer is a compound having a urethane bond (-NHCOO-) and two or more (meth) acryloyloxy groups in the molecule. Specifically, a urethanation reaction product of a hydroxyl group-containing (meth) acrylate monomer having at least one (meth) acryloyloxy group and at least one hydroxyl group in a molecule with a polyisocyanate, or a polyol is reacted with a polyisocyanate (Meth) acrylate monomer having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule, and the like can be used as the urethanization reaction product of the terminal isocyanate group-containing urethane compound.

Examples of the hydroxyl group-containing (meth) acrylate monomer used in the urethanization reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) (Meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (pentaerythritol tri (meth) acrylate, pentaerythritol tri Methacrylate, and the like.

Examples of the polyisocyanate to be provided in the urethane formation reaction with such a hydroxyl group-containing (meth) acrylate monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate Diisocyanates obtained by hydrogenating aromatic isocyanates in these diisocyanates (for example, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.), triphenylmethane triisocyanate, and dibenzylbenzene triisocyanate. - or triisocyanate, and a polyisocyanate obtained by mass-increasing the above-mentioned diisocyanate.

In addition to the aromatic, aliphatic and alicyclic polyols, polyester polyols, polyether polyols and the like can be used as the polyols used for forming the terminal isocyanate group-containing urethane compound by the reaction with the polyisocyanate. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, , Pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A, and the like.

The polyester polyol is obtained by a dehydration condensation reaction between the polyol and the polybasic carboxylic acid or anhydride thereof. Examples of the polybasic carboxylic acid or its anhydride include succinic anhydride, adipic acid, maleic anhydride, itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) Isophthalic acid, terephthalic acid, hexahydrophthalic anhydride, and the like.

The polyether polyol may be a polyoxyalkylene-modified polyol obtained by the reaction of the polyols or dihydroxybenzenes with the alkylene oxide in addition to the polyalkylene glycol.

The polyester (meth) acrylate oligomer is a compound having an ester bond in the molecule and two or more (meth) acryloyloxy groups. Specifically, it can be obtained by a dehydration condensation reaction of (meth) acrylic acid, a polybasic carboxylic acid or anhydride thereof, and a polyol. Examples of the polybasic carboxylic acid or its anhydride used in the dehydration condensation reaction include succinic acid, adipic acid, (maleic anhydride) maleic acid, (anhydride) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, Hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the polyol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, Trimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A, and the like.

The epoxy (meth) acrylate oligomer can be obtained by an addition reaction of polyglycidyl ether and (meth) acrylic acid, and has at least two (meth) acryloyloxy 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, bisphenol A Diglycidyl ether, and the like.

Among the above-mentioned (meth) acrylate compounds, compounds having a structure represented by the following formula (XI) or (XII) can provide a cured product with a high modulus of elasticity and, in combination with a cationic polymerizable compound, particularly an alicyclic epoxy compound, It is preferable in that a protective layer excellent in adhesion to a film can be obtained.

(XI)

(XII)

Wherein Q ₁ and Q ₂ independently represent a (meth) acryloyloxy group or a (meth) acryloyloxyalkyl group, wherein the alkyl has 1 to 10 carbon atoms and Q ₃ is hydrogen or a To 10 carbon atoms)

In the above formula (XI) or (XII), when Q ₁ or Q ₂ is a (meth) acryloyloxyalkyl group, the alkyl may be linear or branched and may have 1 to 10 carbon atoms, 1 to 6 is sufficient. In addition, in the general formula XII, when Q ₃ is a hydrocarbon group, and straight chain or branched and may be, typically, it may be an alkyl group. The alkyl group in this case generally has about 1 to 6 carbon atoms.

The compound represented by the general formula (XI) is a di (meth) acrylate derivative of hydrogenated dicyclopentadiene or tricyclodecanedialcohol, and specific examples thereof include those exemplified above, but hydrogenated dicyclopentadienyl di (meth) acrylate [in the formula _{XI, Q 1 = Q 2 =} ( meth) compounds of the acryloyloxy group-acryloyl] according to, tricyclo to tandi methanol di (meth) acrylate formula _{XI, Q 1 = Q 2 =} ( meth) acrylate Butyloxymethyl group], and the like.

The compound represented by the general formula (XII) is a di (meth) acrylate derivative of dioxane glycol or dioxane dialkanol, and specific examples thereof include 1,3-dioxane-2,5-diyl di meth) acrylate [alias: dioxane glycol di (meth) in the acrylate, formula _{XII, Q 1 = Q 2 =} ( meth) acryloyloxy group with an acrylic, a compound of Q ₃ = H], hydroxy Sangapi aldehyde and trimethylolpropane (Meth) acrylate of an acetal compound [trade name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl 5-5-hydroxymethyl- (Compounds of the formula XII in which Q ₁ = (meth) acryloyloxymethyl group, Q ₂ = 2- (meth) acryloyloxy-1,1-dimethylethyl group and Q ₃ = ethyl group] .

In the curable composition used for forming the first protective layer, the (meth) acrylic compound is preferably contained in a proportion of not more than 70% by weight of the total active energy ray-curable compound, more preferably in a proportion of 35 to 70% , More preferably from 40 to 60% by weight. When the content of the (meth) acrylic compound exceeds 70% by weight, the adhesion with the polarizing film tends to be lowered.

When the curable composition contains a radically polymerizable compound such as the (meth) acrylic compound as described above, it is preferable that a photo radical polymerization initiator is blended. The photo radical polymerization initiator may be one that can initiate polymerization of a radical polymerizable compound such as a (meth) acrylic compound by irradiation with an active energy ray, and conventionally known ones can be used. Specific examples of the photoradical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxypropyl- Acetophenone based initiators including -1- [4- (methylthio) phenyl-2-morpholinopropane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-15-one; Benzophenone initiators including benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; Benzoin ether initiators including benzoin propyl ether, benzoin ethyl ether; Thioxanthone initiators including 4-isopropylthioxanthone; Other xanthones, fluorenone, kanpahquinone, benzaldehyde, anthraquinone, and the like.

The blending amount of the photo radical polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the radical polymerizable compound such as a (meth) acrylic compound. If the blending amount of the photo radical polymerization initiator is too small, the curing becomes insufficient and the mechanical strength and adhesion between the protective layer and the polarizing film tend to be lowered. If the blending amount of the photo radical polymerization initiator is too large, there is a possibility that the durability performance of the obtained polarizing plate is lowered.

The curable composition may further contain a photosensitizer, if necessary. By using the photosensitizer, the reactivity of the cationic polymerization and / or the radical polymerization of the active energy ray-curable compound is improved, so that the mechanical strength of the protective layer and the adhesion between the protective layer and the polarizing film can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfates, redox compounds, azo and diazo compounds, halogen compounds, and photoreducing pigments. Specific photosensitizers include, for example, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and?,? -Dimethoxy-? -Phenylacetophenone; Benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, methyl o-penoleylbenzoate, 4,4'-bis (dimethylamino) benzophenone, and 4,4'-bis (diethylamino) benzophenone; Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; Anthraquinone derivatives such as 2-chloro anthraquinone and 2-methyl anthraquinone; Acridone derivatives such as N-methyl acridone, N-butyl acridone; Other?,? -Diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound and the like. These may be used alone or in combination. The photosensitizer is preferably contained in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the active energy ray-curable compound.

In addition, the curable composition may contain an antistatic agent for imparting an antistatic property to the polarizing plate. The antistatic agent is not particularly limited, and known antistatic agents can be used. Cationic surfactants such as acyloyl amide propyl dimethyl hydroxyethyl ammonium nitrate, acyloyl amide propyl trimethyl ammonium sulfate, cetylmorpholium methosulfate; Anionic surfactants such as a linear alkylphosphate potassium salt, a polyoxyethylene alkylphosphate potassium salt, and an alkanesulfonic acid salt; Nonionic surfactants such as N, N-bis (hydroxyethyl) -N-alkylamine, fatty acid ester derivatives thereof, and polyhydric alcohol fatty acid partial esters. The compounding ratio of these antistatic agents is appropriately determined depending on the desired characteristics, but is usually about 0.1 to 20 parts by weight based on 100 parts by weight of the active energy ray curable compound.

To the curable composition, a known polymer additive commonly used in polymer materials may be added. For example, a primary antioxidant such as a phenol type or an amine type, a secondary antioxidant of a sulfur type, a hindered amine type light stabilizer (HALS), a benzophenone type, a pentathriazole type, .

Further, silica fine particles may be added to the curable composition. By adding silica fine particles, the hardness and mechanical strength of the obtained protective layer can be further improved.

The fine silica particles can be compounded in the curable composition as a liquid material dispersed in, for example, an organic solvent.

The silica fine particles may have a reactive functional group such as hydroxyl group, epoxy group, (meth) acryloyl group, and vinyl group on its surface. The particle size of the fine silica particles is usually 100 nm or less, preferably 5 to 50 nm or so. If the particle size of the fine particles exceeds 100 nm, an optically transparent protective layer tends not to be obtained.

When silica fine particles dispersed in an organic solvent are used, the silica concentration thereof is not particularly limited, and a commercially available product, for example, about 20 to 40% by weight can be used.

Examples of the fine silica particles dispersed in commercially available organic solvents include "methanol silica sol" (silica particle diameter 10 to 15 nm, solid content 30% by weight, manufactured by Nissan Chemical Industries, Ltd.) in which the organic solvent is methyl alcohol, (Silica particle diameter 20 to 25 nm, solid content 40% by weight, manufactured by Nissan Chemical Industries, Ltd.), "OSCAL 1132" (manufactured by Shokubai Kasei Kogyo Co., Ltd., silica particle diameter 10 to 20 nm , Solid content: 30 to 31% by weight): "OSCAL 1232" (silica particle diameter 10 to 20 nm, solid content 30 to 31% by weight, manufactured by Shokuba Kasei Kogyo Co., Ltd.) in which the organic solvent is ethyl alcohol; "OSCAL 1332" (manufactured by Shokuba Kasei Kogyo Co., Ltd., silica particle diameter: 10 to 20 nm, solid content: 30 to 31 wt%) in which the organic solvent is n-propyl alcohol: "IPA-ST" (Silica particle diameter: 10 to 20 nm, solid content: 30 to 31 wt%, manufactured by Shokuba Kasei Kogyo Co., Ltd.), silica particle diameter 10 to 15 nm, ; Manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 20 wt%), "OSCAL 1532" (manufactured by Shokubai Kasei Kogyo Co., Ltd.) , Silica particle diameter 10 to 20 nm, solid content 30 to 31 wt%); &Quot; EG-ST &quot; (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 20% by weight) in which the organic solvent is ethylene glycol; Quot; OSCAL 1632 &quot; (silica particle diameter: 10 to 20 nm, solid content: 30 to 31 wt%, manufactured by Shokubai Kasei Kogyo Co., Ltd.) in which the organic solvent is ethyl cellosolve; "NPC-ST" (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight), the organic solvent being ethylene glycol mono n-propyl ether; DMAC-ST-ZL "(trade name, manufactured by Nissan Chemical Industries, Ltd., silica particle diameter: 10 to 15 nm, solid content: 20% by weight), which is an organic solvent, Silica particle diameter 70 to 100 nm, solid content 20% by weight); &Quot; XBA-ST &quot; (silica particle diameter 10 to 15 nm, solid content 30% by weight, manufactured by Nissan Chemical Industries, Ltd.) in which the organic solvent is a mixture of xylene and n-butyl alcohol; &Quot; MIBK-ST &quot; (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight) having an organic solvent of methyl isobutyl ketone; SP-1120 &quot; (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight), which is methyl ethyl ketone, Silica particle diameter 15 to 20 nm, solid content 5 to 10% by weight), and SP-6120 (manufactured by Konishi Chemical Industry Co., Ltd., silica particle diameter 15 to 20 nm, solid content 5 to 10% One or more of these may be preferably used. "Snowtex 20" (silica particle diameter 10 to 20 nm, manufactured by Nissan Chemical Industries, Ltd.) and "Snowtex C" (silica particle diameter 10 to 20 nm, manufactured by Nissan Chemical Industries, Ltd.) Can also be used.

The silica fine particles are preferably added in an amount of 5 to 250 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of the active energy ray curable compound contained in the curable composition. If the addition amount of the silica fine particles is too small, the hardness of the protective layer may not be sufficiently improved due to the addition of the silica fine particles. On the other hand, if the added amount of the fine silica particles is too large, the adhesion between the polarizing film and the protective layer may be deteriorated. If the amount of the fine silica particles to be added is too large, the dispersion stability of the fine particles in the curable composition may deteriorate or the viscosity of the curable composition may excessively increase.

In addition, the curable composition may contain a solvent as required. The solvent is appropriately selected depending on the solubility of the components constituting the curable composition. Commonly used solvents include aliphatic hydrocarbons such as n-hexane and cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Alcohols such as methanol, ethanol, propanol, isopropanol and n-butanol; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Esters such as methyl acetate, ethyl acetate and butyl acetate; Cellosolve such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; And halogenated hydrocarbons such as methylene chloride and chloroform. The compounding ratio of the solvent is appropriately determined in terms of the viscosity of the desired curable composition in consideration of processability such as film forming property.

Further, the curable composition may contain a leveling agent as required. When the curable composition is applied on a polarizing film or a substrate, when the wettability to the polarizing film or the substrate is insufficient, or when the surface property of the cured product of the curable composition is poor, a leveling agent can be added to improve the wettability. As the leveling agent, various compounds such as a silicone type, a fluorine type, a polyether type, an acrylic acid copolymer type, a titanate type and the like can be used. These leveling agents may be used alone or in combination of two or more.

The leveling agent is preferably added in an amount of 0.01 to 1 part by weight, more preferably 0.1 to 0.7 part by weight, and still more preferably 0.2 to 0.5 part by weight based on 100 parts by weight of the active energy ray-curable compound contained in the curable composition to be. When the amount of the leveling agent added is too small, the improvement in wettability and surface properties may not be sufficient. If the amount of the leveling agent added is too large, the adhesion between the polarizing film and the protective layer may be deteriorated.

The thickness of the first protective layer formed from the curable composition containing the active energy ray-curable compound as described above is preferably 0.1 to 10 占 퐉, more preferably 1 to 5 占 퐉. If the thickness of the first protective layer is too thin, the durability becomes insufficient. If it is too thick, the effect of reducing the thickness of the polarizing plate becomes small. A method of forming the first protective layer using the curable composition will be described later.

(2) Second protective layer

The second protective layer including the thermoplastic resin film is laminated on the surface of the polarizing film opposite to the side where the first protective layer is laminated, through the adhesive layer. As the second protective layer in the polarizing plate of the present invention, there may be mentioned, for example, cellulose acylate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, A thermoplastic resin film made of a suitable material widely used as a material for forming a protective layer in the field in the field can be used without particular limitation. From the viewpoints of mass productivity and adhesiveness, it is preferable to use a cellulose acetate resin film or a cycloolefin resin film as the second protective layer. Further, from the viewpoints of easiness of providing a surface treatment layer and optical properties, it is more preferable to use a cellulose acetate resin film as a second protective layer.

The cycloolefin resin that can be preferably used for the second protective layer in the present invention is a resin having a unit of a monomer containing a cyclic olefin (cycloolefin) such as norbornene or a polycyclic norbornene monomer (Also referred to as a thermoplastic cycloolefin-based resin). The cycloolefin resin may be a hydrogenated product of a ring-opening polymer of the cycloolefin, a ring-opening copolymer using two or more kinds of cycloolefins, an addition polymer to an aromatic compound having a cycloolefin, a chain olefin, have. It is also effective that a polar group is introduced.

When the second protective layer is constituted by using a copolymer of cycloolefin and a chain-like olefin and an aromatic compound having a vinyl group, examples of the chain olefin include ethylene and propylene. Examples of the aromatic compound having a vinyl group include styrene, Methyl styrene, and nuclear alkyl-substituted styrene. In such a copolymer, the unit of the monomer composed of cycloolefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, in the case of constituting the second protective layer by using a ternary copolymer of cycloolefin, chain olefin and aromatic compound having vinyl group, the unit of the monomer composed of cycloolefin can be relatively small as described above . In such a ternary copolymer, the unit of the monomer composed of the chain olefin is usually 5 to 80 mol%, and the unit of the monomer composed of the aromatic group having the vinyl group is usually 5 to 80 mol%.

Examples of the cycloolefin resin include commercially available products such as "Topas" (manufactured by Tico Corporation), "Aton" (manufactured by JSR Corporation), "Zeonor" (manufactured by Nippon Zeon Co., Ltd.) ZEONEX "(manufactured by Nippon Zeon Co., Ltd.) and" APEL "(manufactured by Mitsui Chemicals, Inc.) (all trade names). When the cycloolefin resin is formed into a film, known methods such as solvent casting method and melt extrusion method are suitably used. (Manufactured by Sekisui Chemical Co., Ltd.), &quot; SCA40 &quot; (manufactured by Sekisui Chemical Co., Ltd.), &quot; Zeonor film &quot; A commercially available product of a film of a preformed cycloolefin resin production may be used as the second protective layer.

The cycloolefin resin film used as the second protective layer may be uniaxially or biaxially stretched. In this case, the draw ratio is usually 1.1 to 5 times, preferably 1.1 to 3 times.

The cellulose acetate-based resin film that can be preferably used as the second protective layer in the present invention is a film made of a cellulose part or a completely acetic acid esterified product. For example, a triacetyl cellulose film, a diacetyl cellulose film, .

Examples of the cellulose acetate-based resin constituting the cellulose acetate-based resin film include commercially available products such as Fuji Tack TD80 (manufactured by Fuji Photo Film Co., Ltd.), Fuji Tack TD80UF (manufactured by Fuji Photo Film Co., Ltd.) Fuji Tack TD80UZ "(manufactured by Fuji Photo Film Co., Ltd.)," KC8UX2M "(manufactured by Konica Minolta Opt Co., Ltd.) (all trade names).

The thickness of the second protective layer used in the polarizing plate of the present invention is preferably as small as possible, but if it is too thin, the strength tends to deteriorate and workability tends to deteriorate. If too thick, transparency deteriorates, There is a tendency. From this point of view, the thickness of the second protective layer in the polarizing plate of the present invention is usually 5 to 200 占 퐉, preferably 10 to 150 占 퐉, more preferably 20 to 100 占 퐉 in the case of the protective layer composed of the cycloolefin resin μm, and in the case of a protective layer composed of a cellulose acetate resin, it is usually 20 to 200 μm, preferably 30 to 150 μm, and more preferably 40 to 100 μm.

In the polarizing plate of the present invention, the second protective layer may be a surface treated on the surface opposite to the surface to which the polarizing film is adhered, such as antiglare treatment, hard coating treatment, antistatic treatment and antireflection treatment. A coating layer containing a liquid crystalline compound, a high molecular weight compound thereof and the like may be formed on the surface of the second protective layer opposite to the surface to be adhered to the polarizing film.

The polarizing film and the second protective layer (thermoplastic resin film) are adhered using the adhesive described below. In the adhesion of these films using an adhesive, in order to improve the adhesiveness, the adhesive surface of the polarizing film and / or the second protective layer bonded thereto is subjected to plasma treatment, corona treatment, ultraviolet ray irradiation treatment, frame (flame) treatment , Surface treatment such as saponification treatment may be appropriately carried out. As the saponification treatment, a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide may be mentioned. Hereinafter, the adhesive used for adhesion between the polarizing film and the second protective layer will be described.

(Adhesive layer)

The adhesive layer of the polarizing plate of the present invention is composed of an adhesive (adhesive composition) used for adhesion between the polarizing film and the second protective layer or a cured product thereof. The adhesive composition in the present invention is not particularly limited, but a curable composition containing an active energy ray-curable compound, a curing composition in which an adhesive component is dissolved in water, or an aqueous curing agent in which an adhesive component is dispersed in water have. Of these, it is preferable to use a curable composition containing an active energy ray-curable compound in the point that a drying step is unnecessary.

The curable composition as the adhesive composition may be the same as the curable composition for forming the first protective layer. The curable composition for forming the first protective layer and the active energy ray-curable compound contained therein, the curable composition as the adhesive composition, and the active energy ray-curable compound contained therein may be the same or different.

As an adhesive for an aqueous base in which an adhesive component is dissolved in water or an adhesive component is dispersed in water, an adhesive composition using a polyvinyl alcohol resin or a urethane resin as a main component may be mentioned.

When a polyvinyl alcohol-based resin is used as the main component of the water-based adhesive, the polyvinyl alcohol-based resin may contain, in addition to the partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, a carboxyl group-modified polyvinyl alcohol, an acetoacetyl- Modified polyvinyl alcohol resins such as polyvinyl alcohol modified with an alkyl group, polyvinyl alcohol modified with an amino group, and the like. When a polyvinyl alcohol-based resin is used as an adhesive component, the adhesive is often produced as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the adhesive is usually about 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of water.

To improve adhesiveness, it is preferable to add a curing component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to an adhesive containing a polyvinyl alcohol-based resin as a main component. Examples of water-soluble epoxy resins include polyamides obtained by reacting epichlorohydrin with polyamide polyamines obtained by the reaction of polyalkylene polyamines such as diethylene triamine and triethylene tetramine with dicarboxylic acids such as adipic acid, Amide polyamine epoxy resins. Examples of commercially available products of such polyamide polyamine epoxy resins include "Sumirez Resin 650" and "Sumirez Resin 675" sold by Sumika Chemtech Co., Ltd. and "WS-525" sold by Nippon PMC Co., , And these can be preferably used. The amount of the curable component or crosslinking agent to be added is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight, based on 100 parts by weight of the polyvinyl alcohol-based resin. When the amount of addition is small, the effect of improving the adhesiveness is small. On the other hand, when the amount of addition is large, the adhesive layer tends to be torn.

When a urethane resin is used as a main component of an aqueous adhesive, examples of suitable adhesive compositions include a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer-type urethane resin referred to here is a urethane resin having a polyester skeleton in which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomeric urethane resin is preferable as an aqueous adhesive since it emulsifies directly in water without using an emulsifier to become an emulsion. The polyester ionomer type urethane resin itself is known. For example, Japanese Patent Application Laid-Open No. 7-97504 discloses a polyester ionomer-type urethane resin as an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium, and Japanese Patent Laid-Open Publication No. 2005-070140 JP-A-2005-181817 discloses a method in which a mixture of a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group is used as an adhesive, and a polarizing film containing a polyvinyl alcohol-based resin is mixed with a cycloolefin- And a form of bonding the film is shown.

The thickness of the adhesive layer of the present invention is preferably 20 占 퐉 or less, more preferably 10 占 퐉 or less, and further preferably 5 占 퐉 or less. When the thickness of the adhesive layer is small, there is little possibility of damaging the appearance of the polarizing plate.

(Pressure-sensitive adhesive layer)

Further, the polarizing plate of the present invention may have a pressure-sensitive adhesive layer on the surface of the first protective layer opposite to the polarizing film side. Such a pressure-sensitive adhesive layer can be used, for example, for bonding with a liquid crystal cell. When the polarizing plate and the liquid crystal are bonded to each other by using the pressure-sensitive adhesive layer to form a liquid crystal display device, the protective layer interposed between the polarizing film and the liquid crystal cell is formed of a cured product of the curable composition, The first protective layer is almost zero, so that it is possible to effectively prevent light leakage in black display.

The pressure-sensitive adhesive layer may be formed, for example, by dissolving or dispersing a pressure-sensitive adhesive composition such as a base polymer to become a pressure-sensitive adhesive component in an organic solvent such as toluene or ethyl acetate to prepare a solution of 10 to 40 wt% A method in which a pressure-sensitive adhesive layer is formed by directly coating it, or a method of forming a pressure-sensitive adhesive layer by previously forming a pressure-sensitive adhesive layer on a protective film and then transferring it onto the first protective layer. The thickness of the pressure-sensitive adhesive layer is determined depending on its adhesive strength and the like, but is usually in the range of 1 to 50 mu m.

Examples of the base polymer include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and the like. Among them, the acrylic pressure sensitive adhesive is excellent in optical transparency, suitable wettability and cohesive force, excellent adhesion to the first protective layer and the liquid crystal cell, weather resistance and heat resistance , It is preferable to select and use those which do not cause peeling problems such as lifting or peeling under the conditions of heating or humidification.

Examples of the acrylic base polymer contained in the acrylic pressure-sensitive adhesive include an alkyl ester of acrylic acid having an alkyl group of 20 or less carbon atoms such as a methyl group, an ethyl group or a butyl group and an alkyl ester of an acrylic monomer containing a functional group such as (meth) acrylic acid or (meth) And an acrylic copolymer. The glass transition temperature of the acrylic copolymer is preferably 25 占 폚 or lower, more preferably 0 占 폚 or lower. The weight average molecular weight of the acrylic copolymer is preferably 100,000 or more.

The pressure-sensitive adhesive layer may contain a filler, a pigment, a colorant, an antioxidant, an ultraviolet absorber, and the like, including inorganic powders such as glass fibers, glass beads, resin beads and metal powders, if necessary. Examples of the ultraviolet absorber include a salicylate ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, a cyanoacrylate compound, and a nickel complex salt compound.

&Lt; Polarizing plate production method >

The polarizing plate of the present invention can be produced through the following process. The order of the following steps (i) and (ii) is not particularly limited and may be performed at the same time.

(i) forming the first protective layer on one side of the polarizing film, and

(ii) bonding the second protective layer to the other surface of the polarizing film through an adhesive.

As the method for forming the first protective layer in the step (i), the following methods can be mentioned. First, a curable composition containing an active energy ray-curable compound for forming a first protective layer is coated on a substrate and, if necessary, dried to provide a coating layer of the curable composition on the surface of the substrate (coating layer forming step) . Next, the polarizing film and the coating layer are bonded to each other so that the coated surface is a bonding surface (coating layer bonding step). Next, a laminate including this polarizing film / coating layer / substrate (when the step (ii) is performed before the step (i), the laminate further includes the adhesive layer and the second protective layer) For example, a coating layer made of a curable composition is cured by irradiating or heating an active energy ray such as a visible ray, ultraviolet ray, X-ray or electron ray from the base side to form a first protective layer (curing step). Finally, the substrate on the first protective layer is removed (substrate removal step). Examples of the substrate include a metal belt, a glass plate, a polyethylene terephthalate film, a polycarbonate film, a triacetylcellulose film, a norbornene film, a polyester film, and a polystyrene film. The surface on which the curable composition is applied may be subjected to, for example, peeling treatment.

As another method of the step (i), a curable composition containing an active energy ray-curable compound forming the first protective layer is directly applied to a polarizing film, and an active energy ray is irradiated or heated to form a curable composition And a method of curing the applied layer to form the first protective layer. In this case, the substrate can be made unnecessary.

In the step (ii), as a method for bonding the second protective layer, the following methods can be mentioned. First, an adhesive composition is coated on the second protective layer (thermoplastic resin film) and dried as required. Then, the polarizing film and the second protective layer are bonded to each other so that the coated surface becomes a bonding surface (film bonding step). Next, a laminate including the polarizing film / adhesive / second protective layer (when the step (i) is performed before the step (ii), the laminate further comprises a first protective layer (or a coating of the curable composition Or by irradiating or heating an active energy ray such as visible light, ultraviolet ray, X-ray or electron ray to the laminate to cure the adhesive composition to form a polarizing film and a second protection The layers are adhered and dried as required. When a curable composition containing an active energy ray-curable compound is used as an adhesive composition, the drying process can be omitted, so that the production efficiency can be improved.

Alternatively, the adhesive composition may be cured by directly applying the adhesive composition onto the polarizing film, drying the adhesive composition after bonding the second protective layer, or irradiating or heating the active energy ray to adhere the polarizing film and the second protective layer, Followed by drying.

The first protective layer and the second protective layer may be formed simultaneously. For example, the second protective layer / adhesive / polarizing film / coated layer / adhesive layer / adhesive layer is formed by using a curable adhesive composition (a curable composition containing an active energy ray curable compound, an aqueous adhesive containing a curable component or a crosslinking agent, A polarizer can be obtained by simultaneously curing the adhesive and the coating layer by irradiating or heating an active energy ray on the substrate side, for example, after the laminate including the substrate is produced. According to this method, since the curing process is completed in one cycle, it is possible to further improve the manufacturing efficiency.

In the present invention, there is no particular limitation on the coating method of the curable composition and the adhesive composition containing the active energy ray-curable compound forming the first protective layer, and examples thereof include doctor blade, wire bar, die coater, Various coating methods such as coater can be used. Further, a method of dropping a curable composition or an adhesive composition containing the above-mentioned active energy ray-curable compound between a polarizing film and a second protective layer or a substrate, then pressing it with a roll or the like and pressing it uniformly, As the material, metal or rubber can be used. Also disclosed is a method in which a curable composition or an adhesive composition containing the above-mentioned active energy ray-curable compound is dropped between a polarizing film and a second protective layer or a base material is passed between a roll and a roll, These rolls may be the same material or different materials.

In the case of curing the curable composition and / or adhesive composition containing the active energy ray-curable compound for forming the first protective layer by irradiation with an active energy ray, the light source to be used is not particularly limited, Pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, chemical lamp, black light lamp, microwave-excited mercury lamp, metal halide lamp, and the like.

The light irradiation intensity to the curable composition or the adhesive composition may be different for each composition, but it is preferable that the irradiation intensity in the wavelength region effective for activation of the photo radical polymerization initiator and / or photo cation polymerization initiator is 10 to 2500 mW / cm &lt; 2 & . If the irradiation intensity to the curable composition is less than 10 mW / cm &lt; 2 &gt;, the reaction time becomes excessively long. When the irradiation intensity exceeds 2500 mV / cm &lt; 2 &gt;, heat radiated from the lamp and heat generated during polymerization of the curable composition or adhesive composition, There is a possibility of causing yellowing of the composition or deterioration of the polarizing film. The light irradiation time to the curable composition or the adhesive composition is controlled for each of the above compositions and is not particularly limited, but it is set so that the integrated amount of light, which is expressed as a product of the irradiation intensity and the irradiation time, is 10 to 2500 mJ / desirable. If the total amount of light to the curable composition or the adhesive composition is less than 10 mJ / cm 2, the generation of active species derived from the polymerization initiator is not sufficient and the curing of the obtained protective layer or adhesive layer may be insufficient. In addition, if the average light intensity exceeds 2500 mJ / cm 2, the irradiation time becomes very long, which is disadvantageous for the productivity improvement. The irradiation of the active energy ray is preferably performed within a range in which various performances such as the polarization degree and the transmittance of the polarizing film are not deteriorated.

<Liquid Crystal Display Device>

The liquid crystal display of the present invention comprises the liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, and one or both of the polarizing plates are provided in the liquid crystal cell of the present invention And is a polarizing plate. Here, in the liquid crystal display device of the present invention, the polarizing plate of the present invention is bonded to the liquid crystal cell so that the first protective layer thereof is on the liquid crystal cell side. That is, when the pressure sensitive adhesive layer is provided on the first protective layer, the pressure sensitive adhesive layer is bonded to the liquid crystal cell through the pressure sensitive adhesive layer. The liquid crystal display device of the present invention having such a configuration is effective in preventing light leakage in black display, and at the same time, has been reduced in thickness and weight.

The liquid crystal cell used in the liquid crystal display device of the present invention may be in any mode, but when the IPS mode liquid crystal cell operating in the transverse electric field mode is used, the light leakage prevention effect have.

<Examples>

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, &quot; part &quot; and &quot;% &quot; representing amounts used or contents are based on weight unless otherwise specified.

(Production Example 1: Production of polarizing film)

A polyvinyl alcohol film having an average degree of polymerization of about 2400 and a degree of saponification of 99.9 mol% or more and having a thickness of 75 탆 was immersed in pure water at 30 캜 and immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / 2 / Respectively. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Subsequently, the film was washed with pure water at 8 占 폚 and then dried at 65 占 폚 to obtain a polarizing film in which iodine was adsorbed and oriented in polyvinyl alcohol. The stretching was mainly carried out in a step of iodine dyeing and boric acid treatment, and the total stretching magnification was 5.3 times.

(Preparation Example 2: Preparation of Curable Composition I)

First, the following components were mixed to obtain a curable composition I:

35 parts of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P, manufactured by Daicel Chemical Industries, Ltd.)

15 parts of bis (3-ethyl-3-oxetanylmethyl) ether (AARON oxetane OXT-221, manufactured by Toagosei Co., Ltd.)

50 parts of a diacrylate of an acetal compound of hydroxypivalic aldehyde and trimethylol propane (A-DOG, manufactured by Shin-Nakamura Chemical Co., Ltd.)

2.5 parts of 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCURE 1173 manufactured by Ciba Specialty Chemicals Inc., photo radical polymerization initiator)

2.5 parts of 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate photo cationic polymerization initiator (Yuba Cure 1590 manufactured by Daicel-Cytech)

Silicon leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.) 0.2 part

The above-mentioned A-DOG (diacrylate of acetal compound of hydroxypivalic aldehyde and trimethylol propane) is a compound having the following chemical formula.

(Production Example 3: preparation of curable composition II)

The following components were mixed to obtain a curable composition II.

75 parts of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P, manufactured by Daicel Chemical Industries, Ltd.)

25 parts of bis (3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221 manufactured by Toagosei Co., Ltd.)

5 parts of 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate-based photo cationic polymerization initiator (Yubacure 1590 manufactured by Daicel-Cytech)

Silicon leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.) 0.2 part

(Production Example 4: Production of polyvinyl alcohol-based adhesive)

The following components were mixed to obtain a polyvinyl alcohol-based adhesive.

Pure water 100 parts

1.8 parts of a carboxyl group-modified polyvinyl alcohol (&quot; Kurarupofab KL318 &quot;, manufactured by Kuraray Co., Ltd.)

Sumirez Resin 650 (aqueous solution having a solid content concentration of 30%) of a water-soluble polyamide epoxy resin (SUMIKA CHEMTEX Co., Ltd.)) 0.9 part

(Production Example 5: Production of polarizing plate A)

The polyvinyl alcohol adhesive obtained in Production Example 4 was applied to one side of the polarizing film prepared in Production Example 1, and a protective layer (KC8UY, manufactured by Konica Minolta Opto Co., Ltd.) with saponification treatment and made of triacetylcellulose 80 μm) were bonded. This was dried at 60 DEG C for 6 minutes to prepare a polarizing plate A having a protective layer on one side.

&Lt; Example 1 >

(Manufactured by Daiichirika K.K.) on one side of a polyethylene terephthalate (PET) film (Ester Film E5100, manufactured by Toyobo Co., Ltd.) . Further, a corona discharge treatment was performed on one surface of a protective layer (KC8UX, thickness 80 占 퐉, manufactured by Konica Minolta Opto Co., Ltd.) containing a triacetylcellulose film to which a saponification treatment was not applied, Curable Composition II was applied. At this time, since the film thickness of the coating layer when the curable composition was coated changes depending on the viscosity, the film thickness was adjusted by changing the number of the bar coater line. Next, a PET film having a coating layer of the curable composition I was applied to one surface of the polarizing film produced in Production Example 1, and a protective layer having a coating layer of the curable composition II was coated on the other surface, (LPA3301, manufactured by Fuji Plastics Co., Ltd.) so as to be bonded to the polarizing film.

Ultraviolet rays of 1,500 mJ / cm 2 were irradiated from the side of the PET film to the bonded product by a D valve manufactured by Fusion UV System Co., and the coated layers of the curable compositions I and II arranged on both sides of the polarizing film were cured. Thereafter, the PET film was peeled off, a transparent first protective layer (cured product of the curable composition I) was provided on one side of the polarizing film, and a transparent second protective layer (triacetylcellulose film) was provided on the other side To prepare a polarizing plate. The thickness of the polarizing plate was measured by using a film thickness meter (ZC-101, manufactured by Nikon Corporation) and found to be 116 μm. The thickness of the first protective layer was 4 占 퐉.

&Lt; Example 2 >

(Manufactured by Daiichirika K.K.) on one side of a polyethylene terephthalate (PET) film (Ester Film E5100, manufactured by Toyobo Co., Ltd.) . At this time, since the film thickness of the coating layer when the curable composition was coated changes depending on the viscosity, the film thickness was adjusted by changing the number of the bar coater line. Next, a PET film having the coating layer of the curable composition I was applied on the opposite side of the surface of the polarizing plate A produced in Production Example 5 to which the protective layer was bonded, (LPA3301, manufactured by Plastics Co., Ltd.).

Ultraviolet rays were irradiated from the side of the PET film at a cumulative light quantity of 1500 mJ / cm 2 by the D valve manufactured by Fusion UV System Co., Ltd., and the coating layer of the curable composition I disposed on the polarizing film was cured. Thereafter, the PET film was peeled off to produce a polarizing plate. The thickness of this polarizing plate was 114 μm. The thickness of the first protective layer (cured product of the curable composition I) was 4 占 퐉.

&Lt; Comparative Example 1 &

The polarizing plate A prepared in Production Example 5 was used. The thickness of the polarizing plate A was 110 μm.

&Lt; Comparative Example 2 &

The polyvinyl alcohol adhesive obtained in Preparation Example 4 was applied to both surfaces of the polarizing film prepared in Preparation Example 1 and a protective layer (triacetylcellulose, manufactured by Konica Minolta Opt, Inc., (KC4UEW, thickness: 40 占 퐉) made of triacetyl cellulose on one side and a retardation R _{e in the in-} plane direction and a retardation R _th in the film thickness direction of almost zero (KC4UEW manufactured by Konica Minolta Opt. mu m). This was dried at 60 DEG C for 6 minutes to prepare a polarizing plate. The thickness of this polarizing plate was 150 μm.

&Lt; Evaluation test >

(1) Adhesion endurance test

After the pressure-sensitive adhesive layer was provided on the polarizing plates of Examples 1 and 2 and Comparative Examples 1 and 2 by the following method, the durability of the polarizing plate was evaluated according to the following test method.

[Formation of pressure-sensitive adhesive layer]

A pressure sensitive adhesive solution containing a copolymer of butyl acrylate and acrylic acid, a urethane acrylate oligomer, an isocyanate crosslinking agent and an organic solvent was applied on the first protective layer of the polarizing plates of Examples 1 and 2, on the polarizing film of the polarizing plate of Comparative Example 1, And a protective layer (KC4UEW) comprising triacetyl cellulose of the polarizing plate of Comparative Example 2, and dried to form a pressure-sensitive adhesive layer on each polarizing plate.

[Test Methods]

A heat resistance test in which the above-mentioned pressure-sensitive adhesive layer-attached polarizing plate was bonded to glass via its pressure-sensitive adhesive layer and then kept at a temperature of 80 캜 for 300 hours under drying conditions was carried out. After the test, the polarizing plate after the test was visually observed. The results are shown in Table 1. The evaluation criteria are as follows.

○: Almost no change in appearance such as peeling, peeling, and foaming is observed.

Δ: Appearance changes such as peeling, peeling, and foaming are slightly visible.

X: Appearance change such as peeling, peeling, and foaming is remarkable.

(2) Measurement of retardation of the protective layer

The retardation R _{e in} the plane of the first protective layer (cured product of the curable composition I) used in the polarizing plates of Examples 1 and 2 and the protective layer (KC4UEW) of triacetyl cellulose of the polarizing plate of Comparative Example 2, The retardation R _th was measured by the following method. The results are shown in Table 1. The results of measurement of the retardation of the first protective layer used in the polarizing plates of Examples 1 and 2 were obtained by forming a cured product of the curable composition I on a PET film in the same manner as described above, Thickness 4 μm).

[In-plane retardation R _e ]

The in-plane retardation R _e was measured by a rotating analyzer method using monochromatic light having a wavelength of 559 nm by using a measuring device "KOBRA-21ADH" manufactured by Oji Keio Co., Ltd.

[Retardation R _{th in the} film thickness direction]

Using the same "KOBRA-21ADH" as described above, the retardation R _th in the film thickness direction was measured with monochromatic light having a wavelength of 559 nm. The measurement procedure by this measuring instrument is as follows. The retardation R _e, the thickness of the retardation R _40, film measured by 40 degree slope slow axis as an inclined axis d, and using the average index of refraction n ₀ of the film, the value calculated from Equation 3 to 5 or less in the plane , N _x , n _y and n _z were obtained by substituting these values into the equation (2) to calculate the retardation R _th in the film thickness direction.

R _e = (n _x -n _y ) x d

R ₄₀ = (n _x -n _y ^' ) d / cos ()

_{(n x + n y + n} z) / 3 = n 0

here,

φ = sin ^-1 [sin (40 °) / n ₀ ]

n _y ^' = n _y x n ₀ / [n _y ² sin ₂ (?) + n _z ² cos ² (?)] ^1/2

It should be understood that the disclosed embodiments and examples are illustrative in all respects and not restrictive. The scope of the present invention is not limited to the above description, but is expressed by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 is a schematic cross-sectional view showing a configuration example of an IPS mode liquid crystal display device.

FIG. 2 is a schematic perspective view showing an example of a normal black for explaining the principle of the IPS mode. FIG. 2 (A) shows a state in which a voltage is not visible and FIG. 2 (B) shows a state when a voltage is applied.

3 is a schematic cross-sectional view showing a preferred example of the polarizing plate according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

17 liquid crystal cell, 11 liquid crystal cell, 11 cell, 13 electrode, 14 liquid crystal layer, 15 liquid crystal molecule, 16 linear polarized light incident on liquid crystal cell, 17 linear polarized light after passing through liquid crystal cell, The polarizing plate of the front side and the polarizing plate of the polarizing plate of the front side of the polarizing plate of the present invention; Adhesive layer, 55 pressure-sensitive adhesive layer.

Claims (16)

A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, A first protective layer comprising a cured product of a curable composition containing an active energy ray-curable compound containing an epoxy compound having at least one epoxy group in a molecule, the first protective layer being laminated on one side of the polarizing film; A second protective layer comprising a thermoplastic resin film laminated on the other surface of the polarizing film through an adhesive layer, And, To a retardation value of R _e is in the range 0≤R _e ≤20 in the surface of the first protective layer to be defined by the equation (1), To the R _th retardation value in the film thickness direction of the first protective layer to be defined by the equation (2) is in the range of │R _th │≤25, And the second protective layer comprises a copolymer of cycloolefin and an aromatic compound having a chain olefin and a vinyl group. [Equation 1] R _e = (n _x -n _y ) x d &Quot; (2) &quot; R _th = _{[(n x + n y) /} 2-n z × d] here, n _x : refractive index in the in-plane slow axis direction of the first protective layer n _y : refractive index in the in-plane fast axis direction (direction perpendicular to the slow axis direction) of the first protective layer n _z : refractive index in the thickness direction of the first protective layer d: thickness of the first protective layer The polarizing plate according to claim 1, wherein the epoxy compound does not contain an aromatic ring in the molecule. The polarizer according to claim 1, wherein the epoxy compound has at least one epoxy group bonded to an alicyclic ring. The polarizing plate according to any one of claims 1 to 3, wherein the curable composition further comprises an oxetane-based compound as the active energy ray-curable compound. The curable composition according to any one of claims 1 to 3, wherein the active energy ray-curable compound further comprises (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule Polarizer. The polarizer according to any one of claims 1 to 3, wherein the first protective layer has a thickness of 0.1 to 10 占 퐉. delete The polarizing plate according to any one of claims 1 to 3, wherein the adhesive layer comprises a cured product of a curable composition containing an active energy ray-curable compound. The polarizing plate according to any one of claims 1 to 3, further comprising a pressure-sensitive adhesive layer laminated on a surface of the first protective layer opposite to the polarizing film side. The polarizing plate according to any one of claims 1 to 3, which is used in a liquid crystal display device operating in an in-plane switching (IPS) mode. A liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, Wherein at least one of the pair of polarizing plates is the polarizing plate according to claim 9, and is bonded to the liquid crystal cell through the pressure-sensitive adhesive layer. A liquid crystal cell and a pair of polarizing plates disposed on both sides of the liquid crystal cell, Wherein the pair of polarizing plates are the polarizing plate according to claim 9, and are bonded to the liquid crystal cell through the pressure-sensitive adhesive layer. The liquid crystal display device according to claim 11, wherein the liquid crystal cell has two substrates and a liquid crystal layer sandwiched between the substrates and oriented substantially parallel to the substrate in a voltage unapplied state, Display device. A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, A first protective layer comprising a cured product of a curable composition containing an active energy ray-curable compound containing an epoxy compound having at least one epoxy group in a molecule, the first protective layer being laminated on one side of the polarizing film; And a second protective layer comprising a thermoplastic resin film laminated on the other surface of the polarizing film through an adhesive layer, A coating layer forming step of providing a coating layer of the curable composition on the surface of a substrate; A coating layer joining step of joining a coating layer of a curable composition provided on a surface of the substrate to one side of the polarizing film, A film bonding step of bonding the second protective layer to the other surface of the polarizing film through an adhesive, A curing step of curing the coating layer and the adhesive, A substrate removing step of removing the substrate And, To a retardation value of R _e is in the range 0≤R _e ≤20 in the surface of the first protective layer to be defined by the equation (1), To the R _th retardation value in the film thickness direction of the first protective layer to be defined by the equation (2) is in the range of │R _th │≤25, Wherein the second protective layer is made of a copolymer of a cycloolefin, an aromatic compound having a chain olefin and a vinyl group. [Equation 1] R _e = (n _x -n _y ) x d &Quot; (2) &quot; R _th = _{[(n x + n y) /} 2-n z × d] here, n _x : refractive index in the in-plane slow axis direction of the first protective layer n _y : refractive index in the in-plane fast axis direction (direction perpendicular to the slow axis direction) of the first protective layer n _z : refractive index in the thickness direction of the first protective layer d: thickness of the first protective layer 15. The method of manufacturing a polarizing plate according to claim 14, wherein curing of the coating layer and the adhesive in the curing step is performed simultaneously with irradiation of an active energy ray at the substrate side. The liquid crystal display device according to claim 12, wherein the liquid crystal cell has two substrates, and a liquid crystal layer sandwiched between the substrates and having a liquid crystal layer oriented substantially parallel to the substrate in a voltage- Display device.

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