JP2010277063A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IPS-mode liquid crystal display device by which local display unevenness is reduced. <P>SOLUTION: The liquid crystal display device includes: a liquid crystal cell 10 which has two substrates 11, 12 and a liquid crystal layer 15 held between the two substrates and is aligned in parallel to surfaces of two substrates; polarizing plates 20, 30 which are stacked on both surfaces of the liquid crystal cell via adhesive layers 40, 50; and a backlight 70. The polarizing plates 20, 30 respectively have polarizing films 21, 31 and transparent protective layers 25, 35 arranged at sides of the polarizing films opposite to the adhesive layers 40, 50 adhering to the liquid crystal cell. In the liquid crystal display device, when luminance change in a black display state is measured, (1) a period of the luminance change is <4 cm and amplitude of the luminance change is ≤0.03 cd/cm<SP>2</SP>or (2) a period of the luminance change is ≥4 cm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an IPS mode liquid crystal display device.

  Liquid crystal display devices are used in various display devices by taking advantage of low power consumption, low voltage operation, light weight and thinness. Among liquid crystal display devices, an in-plane switching (IPS) mode liquid crystal display device displays an image by driving a nematic liquid crystal that is homogeneously aligned in the absence of an electric field by a lateral electric field. The IPS mode liquid crystal display device has a feature that the viewing angle is wider than the liquid crystal display devices of other drive modes. However, there is a problem that display unevenness peculiar to a liquid crystal display device is relatively conspicuous as compared with display devices in other drive modes.

  Patent Document 1 describes that, as a means for suppressing display unevenness of an image display device, a film in which a standard deviation of luminance in a plane satisfies a predetermined condition is used for an optical film laminated on a polarizing film. ing. However, in the improvement of the optical film, even if the overall display unevenness can be reduced, the improvement of local display unevenness has been insufficient.

JP 2008-3573 A

  An object of the present invention is to provide an IPS mode liquid crystal display device in which local display unevenness is reduced without impairing the characteristic that the viewing angle is wide.

The present invention relates to a liquid crystal cell having two substrates and a liquid crystal layer sandwiched between the two substrates and oriented parallel to the surfaces of the two substrates, on both surfaces of the liquid crystal cell. A liquid crystal display device comprising a pair of polarizing plates laminated via an adhesive layer and a backlight, each polarizing plate for bonding to a polarizing film and a liquid crystal cell of the polarizing film There is provided a liquid crystal display device having a transparent protective layer disposed on the side opposite to the pressure-sensitive adhesive layer and satisfying either of the following (1) or (2) in the change in luminance in a black display state.
(1) The luminance change period is less than 4 cm, and the luminance change amplitude is 0.03 cd / cm ² or less,
(2) The luminance change cycle is 4 cm or more.

  In this liquid crystal display device, at least one of the pair of polarizing plates laminated on both surfaces of the liquid crystal cell has a polarizing film and a transparent protective film laminated on both surfaces of the polarizing film via an adhesive layer Can be. In this case, the transparent protective film disposed on the liquid crystal cell side of the polarizing plate preferably has a thickness direction retardation at a wavelength of 590 nm in the range of −10 to 10 nm. Moreover, it is preferable that the transparent protective film arrange | positioned at the liquid crystal cell side which a polarizing plate consists of cellulose resin or polyolefin resin.

  In the above liquid crystal display device, at least one of the pair of polarizing plates laminated on both surfaces of the liquid crystal cell includes a polarizing film and a transparent protective layer laminated via an adhesive layer on the side of the polarizing film far from the liquid crystal cell. The polarizing film surface opposite to the transparent protective film may be directly laminated on the liquid crystal cell via the adhesive layer.

  In each form in which a transparent protective film is laminated on at least one surface of a polarizing film via an adhesive layer, a polyvinyl alcohol resin and an epoxy resin are used to form the adhesive layer that bonds the polarizing film and the transparent protective film. A water-based adhesive containing can be used. Moreover, the adhesive agent which consists of a curable resin composition containing the epoxy compound hardened | cured by irradiation of an active energy ray or a heating can also be used. The epoxy compound constituting the curable resin composition preferably includes an epoxy compound having at least one epoxy group bonded to an alicyclic ring in the molecule.

  In the above liquid crystal display device, at least one of the pair of polarizing plates laminated on both surfaces of the liquid crystal cell includes a polarizing film and a transparent protective layer laminated via an adhesive layer on the side of the polarizing film far from the liquid crystal cell. And a coating-type transparent protective layer formed of a cured product of a curable resin composition containing an epoxy compound that is cured by irradiation with active energy rays or heating, formed on the liquid crystal cell side of the polarizing film. It can also be configured.

  Furthermore, at least one of the pair of polarizing plates laminated on both surfaces of the liquid crystal cell is a polarizing film and an epoxy compound that is formed on the side of the polarizing film that is far from the liquid crystal cell and that is cured by irradiation with active energy rays or heating. A first coating-type transparent protective layer comprising a cured product of a curable resin composition containing, and an epoxy compound formed on the liquid crystal cell side of the polarizing film and cured by irradiation with active energy rays or heating It can also be comprised with what has a 2nd coating type transparent protective layer which consists of hardened | cured material of curable resin composition.

  When such a coating type transparent protective layer is provided on at least one surface of the polarizing film, the epoxy compound constituting the curable resin composition for forming the coating type transparent protective layer is an epoxy group bonded to an alicyclic ring. It is preferable that the epoxy compound which has at least 1 in a molecule | numerator is included. In addition, since the coating-type transparent protective layer exhibits almost no refractive index anisotropy, the coating-type transparent protective layer on the liquid crystal cell side in particular has an in-plane retardation at a wavelength of 590 nm of 10 nm or less, and a thickness direction retardation. Can be in the range of −10 to 10 nm.

  In any case, the pressure-sensitive adhesive layer for bonding the liquid crystal cell and the polarizing plate is made of an acrylic pressure-sensitive adhesive, and the storage elastic modulus at 23 ° C. is in the range of 0.15 to 10 MPa, and It is preferable that the adhesive strength with the glass is 1 to 30 N / 25 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the IPS mode liquid crystal display device with which the local display nonuniformity was reduced can be provided, without impairing the characteristic that a viewing angle is wide.

It is a cross-sectional schematic diagram which shows the example of the layer structure of the liquid crystal display device which concerns on this invention. It is a cross-sectional schematic diagram which shows an example of the layer structure of the polarizing plate with an adhesive layer bonded by a liquid crystal cell. It is a cross-sectional schematic diagram which shows the example of another layer structure of the polarizing plate with an adhesive layer bonded by a liquid crystal cell. It is a cross-sectional schematic diagram which shows the example of another layer structure of the polarizing plate with an adhesive layer bonded by a liquid crystal cell. It is a cross-sectional schematic diagram which shows the example of another layer structure of the polarizing plate with an adhesive layer bonded by the liquid crystal cell. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 1. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 2. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 3. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 4. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained by the comparative example 1. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 5. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 6. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 7. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 8. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 9. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 10. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 11. FIG. It is a figure which shows the measurement result of the brightness | luminance of the liquid crystal display device obtained in Example 12. FIG.

  The liquid crystal display device of the present invention comprises a liquid crystal panel including a liquid crystal cell 10 and polarizing plates 20 and 30 laminated on both surfaces of the liquid crystal cell with adhesive layers 40 and 50, as shown in a schematic cross-sectional view in FIG. 60 and a backlight 70. The liquid crystal cell 10 includes two substrates 11 and 12 (for example, a glass substrate) and a liquid crystal layer 15 sandwiched between the two substrates and aligned in parallel with the surfaces of the two substrates. Have. The liquid crystal cell included in the liquid crystal display device of the present invention may be a conventionally known one, but in the case of an in-plane switching (IPS) mode liquid crystal cell, a particularly remarkable display unevenness reducing effect can be obtained.

  In this invention, the polarizing plates 20 and 30 laminated | stacked on both surfaces of the liquid crystal cell 10 are on the opposite side to the polarizing films 21 and 31 and the adhesive layers 40 and 50 for bonding to the liquid crystal cell of this polarizing film. It has at least the transparent protective layers 25 and 35 arranged. In the example shown in FIG. 1, the polarizing plate 20 disposed on the opposite side (that is, the viewing side) of the liquid crystal cell 10 is in a state where the transparent protective films 25 and 26 are laminated on both surfaces of the polarizing film 21. The polarizing plate 30 configured and disposed on the backlight 70 side of the liquid crystal cell 10 is also configured with transparent protective films 35 and 36 laminated on both surfaces of the polarizing film 31. The polarizing film 21 and the transparent protective films 25 and 26, and the polarizing film 31 and the transparent protective films 35 and 36 are laminated via an adhesive layer (not shown).

  The form which extracted the polarizing plate with an adhesive layer in which the adhesive layer 40 for bonding it to the liquid crystal cell 10 on the visual recognition side polarizing plate 20 was extracted from FIG. 1 is shown in the cross-sectional schematic diagram of FIG. Other forms that the polarizing plate 20 can take are also shown in schematic sectional views in FIGS. In the example shown in FIG. 3, the transparent protective film 25 is laminated on one side of the polarizing film 21 (the side that is far from the liquid crystal cell 10), and directly on the polarizing film 21 side opposite to the transparent protective film 25, The adhesive layer 40 for bonding to the liquid crystal cell 10 is provided. In the example shown in FIG. 4, the transparent protective film 25 is laminated on one side of the polarizing film 21 (the side that is far from the liquid crystal cell 10), and the polarizing film 21 side (the liquid crystal cell 10 on the opposite side of the transparent protective film 25). A coating-type transparent protective layer 28 made of a cured product of the curable resin composition is formed on the side surface), and a pressure-sensitive adhesive layer 40 for bonding to the liquid crystal cell 10 is provided on the outer side. It is. In the example shown in FIG. 5, the first coating-type transparent protective layer 27 made of a cured product of the curable resin composition is formed on one surface of the polarizing film 21 (the surface on the side far from the liquid crystal cell 10). A second coating-type transparent protective layer 28 made of a cured product of the curable resin composition is formed on the surface opposite to the surface 21 (the surface on the liquid crystal cell 10 side), and further on the outer side, the liquid crystal cell 10. A pressure-sensitive adhesive layer 40 for bonding to the substrate is provided.

  2 to 5 show examples of the layer configuration of the viewing-side polarizing plate 20, but the backlight-side polarizing plate 30 shown in FIG. 1 also has the respective layer configurations shown in FIGS. be able to. In the present invention, the viewing-side polarizing plate 20 and the backlight-side polarizing plate 30 can take any combination shown in FIGS. Although not shown, for example, a coating-type transparent protective layer 27 made of a cured product of the curable resin composition as shown in FIG. 5 is formed on the surface of the polarizing film far from the liquid crystal cell, The pressure-sensitive adhesive layer 40 for bonding to the liquid crystal cell conforming to the example shown in FIG. 3 can be directly provided on the surface on the liquid crystal cell side of the polarizing film.

In the liquid crystal display device of the present invention, the luminance change in the black display state satisfies either of the following (1) or (2).
(1) The luminance change period is less than 4 cm, and the luminance change amplitude is 0.03 cd / cm ² or less,
(2) The luminance change cycle is 4 cm or more.

  The period of luminance change and the amplitude of luminance change are defined as follows. In other words, the liquid crystal display device is in a black display state (voltage is not applied to the liquid crystal cell), the backlight is turned on, and a display that connects one end of the display screen to the other end using a luminance / color unevenness analyzer or luminance meter The luminance on an arbitrary straight line on the screen is measured, and the luminance value at each point on the straight line is acquired. The luminance change period is defined as a distance between peaks of a Bezier curve obtained by drawing a Bezier curve indicating the tendency of the change based on the luminance value data. Here, the Bezier curve is an N-1 order curve obtained from N control points, and is a technique used to draw a smooth curve from a plurality of control points (Wikipedia, Internet address: < http://en.wikipedia.org/wiki/%E3%83%99%E3%82%B8%E3%82%A7%E6%9B%B2%E7%B7%9A>). Actually, in the Bezier curve based on the above brightness value data, when the black display screen is visually observed, the change in brightness is the distance between the peaks that appear across the portion where the unevenness is observed most intensely. Is required. The amplitude of the luminance change is defined as the difference between the maximum value and the minimum value of the luminance (measured value) existing in the period of the Bezier curve (between the two peaks used when determining the luminance change period). Is done.

When the luminance change period defined as described above is less than 4 cm, by adjusting the amplitude of the luminance change to 0.03 cd / cm ² or less, local display unevenness is not recognized, A liquid crystal display device excellent in display quality can be obtained. Further, by adjusting the luminance change period to 4 cm or more, a local display unevenness is not recognized regardless of the amplitude of the luminance change, and a liquid crystal display device excellent in display quality can be obtained.

  Hereinafter, members constituting the liquid crystal display device of the present invention will be described in detail with reference to the reference numerals shown in FIGS.

[Polarized film]
The polarizing films 21 and 31 used in the present invention usually adsorb dichroic dyes by uniaxially stretching a polyvinyl alcohol resin film by a known method, and dyeing the polyvinyl alcohol resin film with a dichroic dye. And a step of treating the polyvinyl alcohol resin film adsorbed with the dichroic dye with an aqueous boric acid solution and a step of washing with water after the treatment with the aqueous boric acid solution.

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. Moreover, the polymerization degree of polyvinyl alcohol-type resin is about 1,000-10,000 normally, and about 1,500-5,000 are preferable.

  What formed the said polyvinyl alcohol-type resin into a film is used as a raw film of a polarizing film. The polyvinyl alcohol-based raw film used in the present invention is cut into a size of 25 cm in length and 4 cm in width so that the longitudinal direction (MD) of the raw film supplied in a roll shape is a long side, and one end in the length direction. When a weight of 7.5 g is attached and immersed in water at 30 ° C. with the weight on the bottom, the film exhibits a dimensional change characteristic in which the elongation of the film is 45 mm or less in 100 seconds and 50 mm or less in 200 seconds. It is preferable. More preferably, it is 43 mm or less in 100 seconds and 48 mm or less in 200 seconds. By adjusting the dimensional change characteristics of the polyvinyl alcohol-based raw film within this range, it is possible to reduce stretching unevenness in the subsequent uniaxial stretching step, whereby the luminance change in the black display state is the above (1). ) Or (2) can be obtained.

  The method for obtaining the polyvinyl alcohol-based raw film having the dimensional change characteristics as described above is not particularly limited. For example, increasing the tension when forming the raw film, It is effective to increase the drying temperature after film formation.

  The film thickness of the polyvinyl alcohol-based raw film thus obtained is not particularly limited, but is, for example, about 10 to 150 μm.

  Uniaxial stretching of the polyvinyl alcohol-based resin film (raw film) can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, you may uniaxially stretch in these several steps.

  In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or may be wet stretching in which stretching is performed in a state where a solvent is used and the polyvinyl alcohol-based resin film is swollen. The draw ratio is usually about 3 to 8 times.

  As a method of dyeing the polyvinyl alcohol resin film with the dichroic dye, for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye is employed. Specifically, iodine or a dichroic dye is used as the dichroic dye. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

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

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1 × 10 ⁻⁴ to 10 parts by weight and preferably about 1 × 10 ⁻³ to 1 part by weight per 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dichroic dye solution used for dyeing is usually about 20 to 80 ° C. Moreover, the immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

  The boric acid treatment after dyeing with a dichroic dye can usually be performed by immersing the dyed polyvinyl alcohol resin film in a boric acid-containing aqueous solution.

  The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight and preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight and preferably about 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and 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, and more preferably 60 to 80 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, 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 ° C. Further, the immersion time is usually about 1 to 120 seconds.

  After washing with water, a drying process is performed to obtain a polarizing film. The drying treatment can be performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably 40 to 70 ° C. In particular, by drying at 70 ° C. or less, necking-in at the time of drying of the polarizing film can be reduced and stretching unevenness can be suppressed, whereby the change in luminance in the black display state is the above (1) or (2 ) Can be obtained. The time for the drying treatment is usually about 60 to 600 seconds, and preferably 120 to 600 seconds.

  The moisture content of the polarizing film after the drying treatment is usually 5 to 20% by weight, and preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. Moreover, when a moisture content exceeds 20 weight%, the thermal stability of a polarizing film may be inferior.

  Thus, the thickness of the polarizing film obtained by subjecting the polyvinyl alcohol-based resin film to uniaxial stretching, dyeing, boric acid treatment and drying treatment can usually be about 5 to 40 μm.

[Transparent protective film placed on the side far from the liquid crystal cell]
In the form in which the transparent protective film 25 is arranged on the side far from the liquid crystal cell 10 of the polarizing film 21 as shown in FIGS. 2, 3, and 4 (the same applies to the backlight side polarizing plate 30), the transparent protective film 25 is It is preferably made of a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, retardation value stability and the like. Examples of such transparent protective film materials include (meth) acrylic resins such as methyl methacrylate resins, chain polyolefin resins such as polypropylene resins, cyclic polyolefin resins, polyvinyl chloride resins, and cellulose. Resin, styrene resin, acrylonitrile / butadiene / styrene copolymer resin, acrylonitrile / styrene copolymer resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, modified Examples include polyphenylene ether resins, polybutylene terephthalate resins, polyethylene terephthalate resins, polysulfone resins, polyether sulfone resins, polyarylate resins, polyamideimide resins, polyimide resins, and the like.

  The above resins can be used alone or in combination of two or more. In addition, a resin obtained by subjecting the resin to any appropriate polymer modification can be used as the material for the transparent protective film. Examples of the polymer modification include copolymerization, cross-linking, molecular terminal modification, stereoregularity control, and mixing including cases involving reactions between different polymers.

  Among these, as a material of the transparent protective film 25 disposed on the side far from the liquid crystal cell, (meth) acrylic resin such as methyl methacrylate resin, polyethylene terephthalate resin, polypropylene resin, or cellulose resin is used. It is preferable to use it.

  The methyl methacrylate resin is a polymer containing 50% by weight or more of methyl methacrylate units. The content of methyl methacrylate units is preferably 70% by weight or more, and may be 100% by weight. The polymer having a methyl methacrylate unit of 100% by weight is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone.

  The methyl methacrylate resin can be usually obtained by polymerizing a monofunctional monomer mainly composed of methyl methacrylate in the presence of a radical polymerization initiator and a chain transfer agent. If desired, a small amount of a polyfunctional monomer may be copolymerized.

  Monofunctional monomers that can be copolymerized with methyl methacrylate include, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxy methacrylate. Methacrylic acid esters other than methyl methacrylate such as ethyl; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, and 2-ethylhexyl acrylate; Hydroxy acrylates such as hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate Alkyl esters; unsaturated acids such as methacrylic acid and acrylic acid; styrenes such as styrene, chlorostyrene, bromostyrene, vinyltoluene and α-methylstyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile; maleic anhydride And unsaturated acid anhydrides such as citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide. These monomers to be copolymerized may be used alone or in combination of two or more.

  Examples of polyfunctional monomers that can be copolymerized with methyl methacrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) acrylate. , Nonaethylene glycol di (meth) acrylate, and ethylene glycol such as tetradecaethylene glycol (meth) acrylate or the oligomers of both end hydroxyl groups esterified with acrylic acid or methacrylic acid; both ends of propylene glycol or its oligomer A hydroxyl group esterified with acrylic acid or methacrylic acid; neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, and butanediol di A hydroxyl group of a dihydric alcohol such as (meth) acrylate esterified with acrylic acid or methacrylic acid; bisphenol A, an alkylene oxide adduct of bisphenol A, or both terminal hydroxyl groups of these halogen-substituted products with acrylic acid or methacrylic acid Esterified; esterified with polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid; ring opening of glycidyl acrylate or glycidyl methacrylate epoxy group at the terminal hydroxyl group of compounds having two or more hydroxyl groups Added: dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and halogen-substituted products thereof, or glycidyl acrylate on alkylene oxide adducts of these dibasic acids Other glycidyl the glycidyl methacrylate epoxy groups of those obtained by ring-opening addition; and aromatic divinyl compounds such as divinylbenzene; allyl (meth) acrylate. Among these, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and neopentyl glycol di (meth) acrylate are preferably used.

  A resin modified by carrying out a reaction between functional groups of the methyl methacrylate resin may be used. Examples of the reaction between such functional groups include, for example, demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylate and a hydroxyl group of 2- (hydroxymethyl) methyl acrylate, or a carboxyl group of acrylic acid. Examples thereof include an intramolecular dehydration condensation reaction with a hydroxyl group of methyl 2- (hydroxymethyl) acrylate.

  Commercially available methyl methacrylate resins can be easily obtained. For example, “Sumipex” (manufactured by Sumitomo Chemical Co., Ltd.), “Acrypet” (manufactured by Mitsubishi Rayon Co., Ltd.), “Delpet” (manufactured by Asahi Kasei Co., Ltd.), “Parapet” (manufactured by Kuraray Co., Ltd.), “Acryviewer” (manufactured by Nippon Shokubai Co., Ltd.), etc.

  The polyethylene terephthalate resin means a resin in which 80 mol% or more of repeating units are composed of ethylene terephthalate, and may contain a dicarboxylic acid component other than terephthalic acid and / or a diol component other than ethylene glycol. . Examples of other dicarboxylic acid components include isophthalic acid, 4,4′-dicarboxydiphenyl, 4,4′-dicarboxybenzophenone, 1,2-bis (4-carboxyphenyl) ethane, adipic acid, sebacic acid, Examples include 1,4-dicarboxycyclohexane. Other diol components include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

  These other dicarboxylic acid components and other diol components can be used in combination of two or more if necessary. Hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid can also be used in combination. Further, as another copolymer component, a dicarboxylic acid component or a diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like may be used.

  Polyethylene terephthalate resin can be produced by direct polycondensation of terephthalic acid and ethylene glycol (and other dicarboxylic acids or other diols as required), dialkyl esters of terephthalic acid and ethylene glycol (and if necessary) Dialkyl esters of other dicarboxylic acids or other diols) by polycondensation while undergoing transesterification, ethylene glycol esters of terephthalic acid (and other dicarboxylic acids if necessary) (and other diols if necessary) For example, a method in which an ester) is polycondensed in the presence of a catalyst is employed. Furthermore, solid phase polymerization can be performed as necessary to improve the molecular weight or reduce the low molecular weight components.

  Polypropylene resin is a resin obtained by polymerizing a chain olefin monomer whose main component is propylene among chain olefin resins using a polymerization catalyst, and 80% by weight or more of repeating units are composed of propylene. It is a chain olefin resin. The polypropylene resin may be a homopolymer of propylene, or a comonomer mainly composed of propylene and copolymerizable with it in a proportion of 1 to 20% by weight, preferably 3 to 10% by weight. It may be a copolymer.

  When using a propylene copolymer, ethylene, 1-butene, and 1-hexene are preferable as a comonomer copolymerizable with propylene. Among them, a copolymer obtained by copolymerizing ethylene at a rate of 1 to 20% by weight, preferably 3 to 10% by weight, is preferable because a resin having relatively excellent transparency can be obtained. By setting the copolymerization ratio of ethylene to 1% by weight or more, an effect of increasing transparency appears. On the other hand, when the ratio exceeds 20% by weight, the melting point of the resin is lowered, and the heat resistance required for the transparent protective film may be impaired.

  The content of the xylene-soluble component (CXS (cold styrene soluble) component) at 20 ° C. of the polypropylene resin is preferably 1% by weight or less, and more preferably 0.5% by weight or less. Among polypropylene resins, a propylene homopolymer having a CXS component of 1% by weight or less, preferably 0.5% by weight or less is one suitable example.

  Polypropylene resins can be easily obtained from commercial products. For example, “Prime Polypro” (manufactured by Prime Polymer Co., Ltd.), “Novatech” and “Wintech” (above, Nippon Polypro Co., Ltd.), “Sumitomo Noblen” (manufactured by Sumitomo Chemical Co., Ltd.), “Sun Aroma” (manufactured by Sun Aroma Co., Ltd.), and the like.

  Cellulosic resins are those in which some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Further, it refers to a cellulose organic acid ester or a cellulose mixed organic acid ester. Examples include cellulose acetate, propionate, butyrate, and mixed esters thereof. Of these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferable.

  As a method of forming the transparent protective film material such as methyl methacrylate resin, polyethylene terephthalate resin, polypropylene resin, and cellulose resin on the transparent protective film 25 for bonding to the polarizing film, the resin is used. The method according to the method may be appropriately selected and is not particularly limited. For example, a solvent-casting method in which a resin dissolved in a solvent is cast onto a metal band or drum, and the solvent is removed by drying to obtain a film. The resin is heated and kneaded above its melting temperature, extruded from a die, and cooled. For example, a melt extrusion method for obtaining a film is employed. In this melt extrusion method, a single layer film can be extruded or a multilayer film can be coextruded.

  A commercially available product can be easily obtained as the transparent protective film 25 disposed on the side far from the liquid crystal cell. For example, in the case of methyl methacrylate resin films, the trade names are "Technoloy" (manufactured by Sumitomo Chemical Co., Ltd.), "Acrylite" and "Acryprene" (manufactured by Mitsubishi Rayon Co., Ltd.), Company-made), “paragrass” and “comograss” (manufactured by Kuraray Co., Ltd.), “acrylic” (manufactured by Nippon Shokubai Co., Ltd.) For polyethylene terephthalate resin films, “Novaclear” (manufactured by Mitsubishi Chemical Corporation), “Teijin A-PET sheet” (manufactured by Teijin Chemicals Ltd.), and the like are listed under the trade names. For polypropylene resin films, “FILMAX CPP film” (manufactured by FILMAX), “Santox” (manufactured by Sun Tox Co., Ltd.), “Tosero” (manufactured by Tosero Co., Ltd.), “Toyobo Pyrene Film” (Toyobo Co., Ltd.), “Trephan” (Toray Film Processing Co., Ltd.), “Nihon Polyace” (Nihon Polyace Co., Ltd.), “Dazai FC” (Futamura Chemical Co., Ltd.), and the like. In the case of cellulosic resin films, “Fujitac TD” (manufactured by Fuji Film Co., Ltd.), “Konica Minolta TAC Film KC” (manufactured by Konica Minolta Opto Co., Ltd.) and the like can be mentioned.

  An anti-glare property (haze) can be imparted to the transparent protective film 25 which is disposed on the side far from the liquid crystal cell and becomes the viewing side. Examples of a method for imparting antiglare properties include a method in which inorganic fine particles or organic fine particles are mixed into the raw material resin to form a film, a resin in which fine particles are mixed and a resin in which fine particles are not mixed by multilayer extrusion. The method consists of forming a two-layer film or forming a three-layer film with a resin mixed with fine particles as an outer layer, and coating a coating solution formed by mixing inorganic fine particles or organic fine particles with a curable binder resin on one side of the film. A method of curing the binder resin and providing an antiglare layer is employed.

  Examples of the inorganic fine particles for imparting antiglare properties include silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, calcium phosphate, and the like. Examples of the organic fine particles include cross-linked polyacrylic acid particles, methyl methacrylate / styrene copolymer resin particles, cross-linked polystyrene particles, cross-linked polymethyl methacrylate particles, silicone resin particles, and polyimide particles.

  It is preferable that the haze value of the transparent protective film 25 provided with the antiglare property is in the range of 6 to 45%. When the haze value of the transparent protective film is less than 6%, a sufficient antiglare effect may not appear. On the other hand, if it exceeds 45%, the screen of the liquid crystal display device using this transparent protective film may be whitened, resulting in a reduction in image quality.

  This haze value can be measured in accordance with JIS K 7136 using a commercially available haze meter (for example, a haze / transmittance meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.). In measuring the haze value, in order to prevent warping of the film, for example, a measurement sample in which the film surface is bonded to a glass substrate using an optically transparent adhesive so that the antiglare property-imparting surface becomes the surface. Is preferably used.

  Functional layers such as a conductive layer, a hard coat layer, and a low reflection layer are provided on the transparent protective film 25 on the side far from the liquid crystal cell and on the transparent protective film 25 on the viewing side and on the transparent protective film 35 on the backlight side. Can do. As the coating liquid containing the binder resin that constitutes the antiglare layer, a resin composition that can exhibit these functions can also be selected.

  The thickness of the transparent protective films 25 and 35 disposed on the side far from the liquid crystal cell is not particularly limited, but is usually about 1 to 500 μm and preferably 10 to 200 μm from the viewpoint of strength and handleability. More preferably, it is 20-100 micrometers. When the thickness is within this range, the polarizing film is mechanically protected, and even when exposed to high temperature and high humidity, the polarizing film does not shrink and stable optical characteristics can be maintained.

[Transparent protective film placed on the liquid crystal cell side]
In the form in which the transparent protective film 26 is disposed on the liquid crystal cell side of the polarizing film 21 as shown in FIG. 2 (the same applies to the backlight side polarizing plate 30), the resin material constituting the transparent protective film 26 is the liquid crystal. Resins similar to those described for the transparent protective film 25 disposed on the side far from the cell can be used. Among these, cellulose-based resins and polyolefin-based resins are preferably used because they are inexpensive, easily available, and easily control the retardation value.

  The polyolefin resin may be, for example, a cyclic polyolefin resin obtained by polymerizing a cyclic olefin monomer such as norbornene or other cyclopentadiene derivative using a polymerization catalyst, or a chain polyolefin type such as the polypropylene resin. Resin may be used. Among these, when a cyclic polyolefin-based resin is used, a transparent protective film having a predetermined retardation value described later can be easily obtained.

  Examples of the cyclic polyolefin-based resin include a resin obtained by performing ring-opening metathesis polymerization from cyclopentadiene and olefins by a Diels-Alder reaction or a derivative thereof as a monomer, followed by hydrogenation; dicyclopentadiene and Resins obtained by ring-opening metathesis polymerization from olefins or methacrylic acid esters using tetracyclododecene or derivatives thereof obtained by Diels-Alder reaction and subsequent hydrogenation; norbornene, tetracyclododecene, them And at least two monomers selected from other cyclic olefin monomers in the same manner by ring-opening metathesis copolymerization followed by hydrogenation; resins obtained by norbornene, tetra Kurododesen or cyclic olefin monomers such as derivatives thereof, such as resins obtained by addition copolymerization of such aromatic compounds having a vinyl group.

  Cyclic polyolefin-based resins can be easily obtained as commercial products. For example, “Topas” (Topas Advanced Polymers GmbH), “Arton” (manufactured by JSR Corporation), and “Zeonor” are trade names. And “ZEONEX” (manufactured by ZEON CORPORATION), “APEL” (manufactured by Mitsui Chemicals, Inc.) and the like.

  Examples of the chain polyolefin resin include a polyethylene resin and a polypropylene resin. Among them, a homopolymer of propylene and a copolymer obtained by copolymerizing propylene as a main component and a comonomer copolymerizable therewith in a proportion of usually 1 to 20% by weight, preferably 3 to 10% by weight. Can be suitably used.

  As a method for producing a transparent protective film from a cyclic polyolefin-based resin, a chain polyolefin-based resin, a cellulose-based resin or the like, a method corresponding to the resin may be appropriately selected, and the method is not particularly limited. For example, a solvent cast method in which a resin dissolved in a solvent is cast onto a metal band or drum, and the solvent is dried and removed to obtain a film. The resin is heated and kneaded above its melting temperature, extruded from a die, and cooled. For example, a melt extrusion method for obtaining a film by cooling by the method is employed. Among these, from the viewpoint of productivity, the melt extrusion method is preferably employed for polyolefin resins.

Transparent protective film 26, 36 disposed on the liquid crystal cell side, in order not to impair the wide viewing angle characteristic having the liquid crystal cell of the IPS mode is originally in the thickness direction at that wavelength 590nm retardation R _th is -25~25nm It is preferable that it exists in the range, Furthermore, the range of -10-10 nm. The retardation _Rth in the thickness direction is a value obtained by multiplying the difference between the in-plane average refractive index and the refractive index in the thickness direction by the thickness of the film, and is represented by the following formula (a). The in-plane retardation R _e is a value obtained by multiplying the thickness of the film to the refractive index difference in the plane, represented by the following formula (b). Transparent protective film 26, 36 disposed on the liquid crystal cell side is preferably more smaller-plane retardation R _e, for example 10nm or less, and further preferably not 5nm or less. R _th and R _e can be obtained by measurement using various commercially available phase difference meter.

R _th = _{[(n x + n y) /} 2-n z ] × d (a)
_{R e = (n x -n y} ) × d (b)
Here, n _x is a refractive index in x-axis direction in the film plane (in-plane slow axis direction), n _y is a refractive index in the y-axis direction in the film plane (in-plane fast axis direction) , _Nz is the refractive index in the direction perpendicular to the film surface (z-axis direction: thickness direction), and d is the thickness of the film.

As a method for controlling the retardation R _th in the thickness direction within the -10nm~10nm at a wavelength 590nm of the transparent protective film 26, 36 disposed on the liquid crystal cell side, in making the transparent protective film, the thickness direction And a method of minimizing the distortion remaining in the substrate. For example, in the solvent casting method, a method of relaxing residual shrinkage strain in the thickness direction that occurs when the cast resin solution is dried by heat treatment is employed. In the melt extrusion method, the distance from the die to the cooling drum is reduced as much as possible in order to prevent the resin film from being extruded from the die and cooled, and the extrusion amount and the rotation speed of the cooling drum are also reduced. A method of controlling the film so that the film is not stretched is employed. In addition, as in the solvent casting method, a method of relaxing strain remaining in the obtained film by heat treatment is also effective.

[Adhesive layer]
When the transparent protective films 25 and 26 are laminated on at least one surface of the polarizing film 21 as in the examples shown in FIGS. 2, 3, and 4 (the same applies to the backlight side polarizing plate 30), It is carried out by providing an adhesive layer between the film and the transparent protective film and integrating them. That is, lamination | stacking with a polarizing film and a transparent protective film is made | formed by adhere | attaching these films using an adhesive agent. At this time, the thickness of the adhesive layer is preferably 0.1 to 35 μm, and more preferably 0.5 to 15 μm. If it is this range, neither the floating nor peeling arises between the transparent protective film and polarizing film which are laminated | stacked, and the adhesive force which does not have a practical problem is obtained.

  For the formation of the adhesive layer, an appropriate adhesive and anchor coating agent can be used as appropriate according to the type and purpose of the adherend. For example, solvent type adhesives, emulsion type adhesives, pressure sensitive adhesives, rewetable adhesives, polycondensation type adhesives, solventless type adhesives, film adhesives, hot melt type adhesives and the like can be mentioned.

  As one of preferable adhesives for forming the adhesive layer, there can be mentioned a water-based adhesive, that is, an adhesive component dissolved in water or an adhesive component dispersed in water. A commercially available thing may be used for a water-system adhesive, and what mixed the solvent and the additive in the commercially available adhesive may be used. One suitable aqueous adhesive includes a polyvinyl alcohol resin as a main component. Polyvinyl alcohol resins that are the main components of this water-based adhesive include partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, as well as modifications such as carboxyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. It may be a polyvinyl alcohol resin. Among them, a saponified product of a copolymer of vinyl acetate and unsaturated carboxylic acid or a salt thereof, that is, carboxyl group-modified polyvinyl alcohol is preferably used. Examples of commercially available carboxyl group-modified polyvinyl alcohol include “KL-318” (trade name, manufactured by Kuraray Co., Ltd.).

  Another suitable water-based adhesive is one based on a urethane resin. The urethane resin used for the water-based adhesive is preferably an ionomer type, particularly a polyester ionomer type urethane resin. Here, the ionomer type is one in which a small amount of an ionic component (hydrophilic component) is introduced into the skeleton constituting the urethane resin. The polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced into the skeleton. Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier and becomes an emulsion. Examples of commercially available polyester ionomer-type urethane resins include “Hydran AP-20” and “Hydran APX-101H” (trade names, both manufactured by DIC Corporation), and are both available in the form of an emulsion.

  Moreover, the water-based adhesive can contain a crosslinking agent. Examples of the crosslinking agent include amine compounds, aldehyde compounds, methylol compounds, epoxy resins, isocyanate compounds, and polyvalent metal salts. When using an aqueous adhesive mainly composed of a polyvinyl alcohol-based resin, it is particularly preferable to use glyoxal or a water-soluble epoxy resin as a crosslinking agent. The water-soluble epoxy resin can be, for example, a resin obtained by reacting an epichlorohydrin with a polyamide polyamine such as diethylenetriamine or triethylenetetramine. As a commercial product thereof, “Smileze Resin 650 (30)” is available. (Trade name, manufactured by Sumika Chemtex Co., Ltd.).

  On the other hand, when using a water-based adhesive mainly comprising a urethane resin, particularly a polyester ionomer type urethane resin, it is preferable to use an isocyanate compound as a crosslinking agent. The isocyanate-based crosslinking agent is a compound having at least two isocyanato groups (—NCO) in the molecule. For example, 2,4-tolylene diisocyanate, phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,6-hexa In addition to polyisocyanate monomers such as methylene diisocyanate and isophorone diisocyanate, adducts in which a plurality of these molecules are added to polyhydric alcohols such as trimethylolpropane, and three molecules of diisocyanate are isocyanurates at each isocyanato group Examples include trifunctional isocyanurates that form rings, and polyisocyanate-modified products such as burettes that are formed by hydration and decarboxylation of three diisocyanate molecules at each isocyanato group.Examples of suitable commercially available isocyanate-based crosslinking agents include “Hydran Assist C-1” (trade name, manufactured by DIC Corporation).

  A polarizing plate can be obtained by applying the water-based adhesive as described above to the adhesive surface of the polarizing film and / or the transparent protective film, bonding them together, and performing a drying treatment. Prior to bonding, it is also effective to subject the transparent protective film to easy adhesion treatment such as saponification treatment, corona discharge treatment or plasma treatment to enhance wettability. A drying temperature can be about 60-100 degreeC, for example. After the drying treatment, curing at a temperature slightly higher than room temperature, for example, at a temperature of about 30 to 50 ° C. for about 1 to 10 days is preferable for further enhancing the adhesive force.

  Another preferred adhesive is an adhesive made of a curable resin composition containing an epoxy compound that is cured by irradiation with active energy rays or heating. In this case, adhesion between the polarizing film and the transparent protective film is performed by irradiating an active energy ray or heating the coating layer of the adhesive to cure the curable epoxy compound contained in the adhesive. Can be done. The curing of the epoxy compound by irradiation with active energy rays or heating is preferably performed by cationic polymerization. The epoxy compound used for the adhesive has at least two epoxy groups in the molecule. Here, the active energy ray is a concept including, for example, visible light, ultraviolet ray, X-ray, electron beam and the like.

  From the viewpoint of weather resistance, refractive index, cationic polymerizability, and the like, the epoxy compound contained in the curable epoxy resin composition as an adhesive is preferably one that does not contain an aromatic ring in the molecule. Examples of such epoxy compounds include hydrogenated epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds.

  A hydrogenated epoxy compound can be obtained by subjecting an aromatic polyhydroxy compound, which is a raw material for an aromatic epoxy resin, to selective hydrogenation under pressure in the presence of a catalyst, followed by glycidyl etherification. . Examples of aromatic epoxy resins include bisphenol-type epoxy resins such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether; phenol novolac epoxy resins, cresol novolac epoxy resins, and hydroxy Examples include novolak-type epoxy resins such as benzaldehyde phenol novolac epoxy resins; glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and polyfunctional epoxy resins such as epoxidized polyvinylphenol. For example, aromatic polyhydroxy compounds such as bisphenols, which are raw materials for these aromatic epoxy resins, are subjected to the nuclear hydrogenation reaction as described above, and then reacted with epichlorohydrin to obtain a hydrogenated epoxy compound. It is done. Among them, as the hydrogenated epoxy compound, hydrogenated bisphenol A glycidyl ether is preferable.

  The alicyclic epoxy compound means an epoxy resin having at least one epoxy group bonded to the alicyclic ring in the molecule. The “epoxy group bonded to the alicyclic ring” means a bridged oxygen atom —O— in the structure represented by the following formula, wherein m is an integer of 2 to 5.

Compounds form group obtained by removing one or more hydrogen atoms of (CH ₂₎ in _m in the above formula is bonded to another chemical structure, it can be a cycloaliphatic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among the alicyclic epoxy compounds, those having an oxabicyclohexane ring (m = 3 in the above formula) and an oxabicycloheptane ring (m = 4 in the above formula) exhibit excellent adhesion. Are preferably used. Although the alicyclic epoxy compound used preferably below is specifically illustrated, it is not limited to these compounds.

  (A) Epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (I):

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

  (B) Epoxycyclohexanecarboxylates of alkanediol represented by the following formula (II):

(In the formula, R ³ and R ⁴ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20).

  (C) Epoxycyclohexyl methyl esters of dicarboxylic acid represented by the following formula (III):

(In the formula, R ⁵ and R ⁶ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p represents an integer of 2 to 20).

  (D) Epoxycyclohexyl methyl ethers of polyethylene glycol represented by the following formula (IV):

(In the formula, R ⁷ and R ⁸ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10).

  (E) Epoxycyclohexyl methyl ethers of alkanediols represented by the following formula (V):

(In the formula, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r represents an integer of 2 to 20).

  (F) Diepoxy trispiro compound represented by the following formula (VI):

(In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

  (G) Diepoxy monospiro compound represented by the following formula (VII):

(In the formula, R ¹³ and R ¹⁴ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

  (H) Vinylcyclohexene diepoxides represented by the following formula (VIII):

(Wherein R ¹⁵ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).
(I) Epoxycyclopentyl ethers represented by the following formula (IX):

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

  (J) Diepoxytricyclodecanes represented by the following formula (X):

(Wherein R ¹⁸ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).
Among the alicyclic epoxy compounds exemplified herein, the following alicyclic epoxy compounds are commercially available or similar, and are more preferably used because they are relatively easy to obtain. .

(A) Esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (7-oxa-bicyclo [4.1.0] hept-3-yl) methanol [formula (I) In which R ¹ = R ² = H]
(B) 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept-3-yl) methanol Ester compounds of [In the formula (I), R ¹ = 4-CH ₃ , R ² = 4-CH ₃ compound],
(C) Esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [in the formula (II), R ³ = R ⁴ = H, n = 2 Compound〕,
(D) (7-oxabicyclo [4.1.0] hept-3-yl) esterified product of methanol and adipic acid [compound of formula (III), wherein R ⁵ = R ⁶ = H, p = 4] ,
(E) (4-Methyl-7-oxabicyclo [4.1.0] hept-3-yl) esterified product of methanol and adipic acid [in the formula (III), R ⁵ = 4-CH ₃ , R ⁶ = 4-CH ₃ , p = 4 compound]
(F) etherified product of (7-oxabicyclo [4.1.0] hept-3-yl) methanol and 1,2-ethanediol [in the formula (V), R ⁹ = R ¹⁰ = H, r = Two compounds].

  Moreover, as an aliphatic epoxy compound, the polyglycidyl ether of an aliphatic polyhydric alcohol or its alkylene oxide addition product can be mentioned. More specifically, 1,4-butanediol diglycidyl ether; 1,6-hexanediol diglycidyl ether; glycerin triglycidyl ether; trimethylolpropane triglycidyl ether; polyethylene glycol diglycidyl ether; propylene Diglycidyl ether of glycol; Polyether of polyether polyol obtained by adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin Examples thereof include glycidyl ether.

  In the adhesive comprising the curable resin composition, the epoxy compound may be used alone or in combination of two or more. The epoxy equivalent of the epoxy compound used for the adhesive is usually in the range of 30 to 3,000 g / equivalent, preferably 50 to 1,500 g / equivalent. When the epoxy equivalent is less than 30 g / equivalent, there is a possibility that the flexibility of the polarizing plate after curing is lowered or the adhesive strength is lowered. On the other hand, if it exceeds 3,000 g / equivalent, the compatibility with other components contained in the adhesive may be lowered.

  From the viewpoint of reactivity, cationic polymerization is preferably used as the curing reaction of the epoxy compound. For that purpose, it is preferable that the curable epoxy resin composition which is an adhesive agent contains a cationic polymerization initiator. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation or heating with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates an epoxy group polymerization reaction. Regardless of the type of cationic polymerization initiator, it is preferable from the viewpoint of workability that latency is imparted. Hereinafter, a cationic polymerization initiator that generates a cationic species or Lewis acid upon irradiation of active energy rays and initiates a polymerization reaction of an epoxy group is referred to as a “photo cationic polymerization initiator”, and generates a cationic species or a Lewis acid by heat. The cationic polymerization initiator that initiates the polymerization reaction of the epoxy group is referred to as “thermal cationic polymerization initiator”.

  The method of curing the adhesive by irradiation with active energy rays using a cationic photopolymerization initiator enables curing at room temperature, reducing the need to consider the heat resistance of the polarizing film or distortion due to expansion, and transparent protection This is advantageous in that the film and the polarizing film can be favorably bonded. In addition, since the cationic photopolymerization initiator acts catalytically by light, it is excellent in storage stability and workability even when mixed with an epoxy compound.

  Although it does not specifically limit as a photocationic polymerization initiator, For example, aromatic diazonium salt; Onium salts, such as an aromatic iodonium salt and an aromatic sulfonium salt; Iron-allene complex etc. can be mentioned.

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

  Examples of the aromatic iodonium salt include diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, bis (4-nonylphenyl) iodonium hexafluorophosphate, and the like.

  Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4′-bis (diphenylsulfonio) diphenylsulfide bis ( Hexafluorophosphate), 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bis (hexafluoroantimonate), 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio ] Diphenyl sulfide bis (hexafluorophosphate), 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [di p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4′-diphenylsulfonio-diphenyl sulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4 Examples include '-diphenylsulfonio-diphenylsulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate.

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

  These photocationic polymerization initiators can be easily obtained as commercial products. For example, “Kayarad PCI-220” and “Kayarad PCI-620” (Nippon Kayaku Co., Ltd. , "UVI-6990" (manufactured by Union Carbide), "Adekaoptomer SP-150" and "Adekaoptomer SP-170" (manufactured by ADEKA, Inc.), "CI-5102", "CIT-" 1370 ”,“ CIT-1682 ”,“ CIP-1866S ”,“ CIP-2048S ”and“ CIP-2064S ”(manufactured by Nippon Soda Co., Ltd.),“ DPI-101 ”,“ DPI-102 ”,“ DPI ” -103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI- 02 ”,“ BBI-103 ”,“ BBI-105 ”,“ TPS-101 ”,“ TPS-102 ”,“ TPS-103 ”,“ TPS-105 ”,“ MDS-103 ”,“ MDS-105 ” , “DTS-102” and “DTS-103” (manufactured by Midori Chemical Co., Ltd.), “PI-2074” (manufactured by Rhodia), and the like.

  These cationic photopolymerization initiators may be used alone or in combination of two or more. Among these, aromatic sulfonium salts are particularly preferable because they have ultraviolet absorption characteristics even in a wavelength region of 300 nm or more, and thus can provide a cured product having excellent curability and good mechanical strength and adhesive strength. Used.

  The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of epoxy compounds, Preferably it is 1 weight part or more, Preferably it is 15 weight part or less. If the amount of the cationic photopolymerization initiator is less than 0.5 parts by weight based on 100 parts by weight of the epoxy compound, the curing becomes insufficient, and the mechanical strength and adhesive strength of the cured product tend to be reduced. Moreover, when the compounding quantity of a photocationic polymerization initiator exceeds 20 weight part with respect to 100 weight part of epoxy compounds, the hygroscopic property of hardened | cured material will become high because the ionic substance in hardened | cured material will increase, and durability. Performance may be degraded.

  When using a photocationic polymerization initiator, the curable epoxy resin composition that is an adhesive may further contain a photosensitizer as necessary. By using a photosensitizer, the reactivity of cationic polymerization is improved, and the mechanical strength and adhesive strength of the cured product can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes.

  More specific examples of the photosensitizer include benzoin methyl ether, benzoin isopropyl ether, and benzoin derivatives such as α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, o-benzoylbenzoate Benzophenone derivatives such as methyl acid, 4,4′-bis (dimethylamino) benzophenone, and 4,4′-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; 2-chloroanthraquinone And anthraquinone derivatives such as 2-methylanthraquinone; acridone derivatives such as N-methylacridone and N-butylacridone; other α, α-diethoxyacetophenone, benzyl, fluore Non-, xanthone, uranyl compounds, halogen compounds and the like can be mentioned. These photosensitizers may be used alone or in combination of two or more. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight in 100 parts by weight of the curable epoxy resin composition.

  On the other hand, examples of the thermal cationic polymerization initiator include benzylsulfonium salt, thiophenium salt, thioranium salt, benzylammonium, pyridinium salt, hydrazinium salt, carboxylic acid ester, sulfonic acid ester, and amine imide. Commercially available products of these thermal cationic polymerization initiators can also be easily obtained. For example, “ADEKA OPTON CP77”, “ADEKA OPTON CP66” (manufactured by ADEKA, Inc.), “CI” are available under the trade names. -2639 "and" CI-2624 "(manufactured by Nippon Soda Co., Ltd.)," Sun-Aid SI-60L "," Sun-Aid SI-80L "and" Sun-Aid SI-100L "(manufactured by Sanshin Chemical Industry Co., Ltd.) Etc.

  The epoxy compound contained in the adhesive may be cured by either photocationic polymerization or thermal cationic polymerization, or may be cured by both photocationic polymerization and thermal cationic polymerization. In the latter case, it is preferable to use a photocationic polymerization initiator and a thermal cationic polymerization initiator in combination.

  The curable epoxy resin composition may further contain a compound that promotes cationic polymerization, such as an oxetane compound or a polyol compound.

  An oxetane compound is a compound having a 4-membered ring ether in the molecule, such as 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, 3 -Ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, phenol novolac oxetane and the like. These oxetane compounds can be easily obtained as commercial products. For example, all of these oxetane compounds are trade names such as “Aron Oxetane OXT-101”, “Aron Oxetane OXT-121”, “Aron Oxetane OXT-211”. , “Aron oxetane OXT-221” and “Aron oxetane OXT-212” (both manufactured by Toagosei Co., Ltd.). These oxetanes are usually contained in the curable epoxy resin composition in a proportion of 5 to 95% by weight, preferably 5 to 50% by weight.

  The polyol compound is preferably one having no acidic group other than the phenolic hydroxyl group, for example, a polyol compound having no functional group other than the hydroxyl group, a polyester polyol compound, a polycaprolactone polyol compound, or a polyol compound having a phenolic hydroxyl group. And polycarbonate polyol compounds. The molecular weight of these polyol compounds is usually 48 or more, preferably 62 or more, more preferably 100 or more, and preferably 1,000 or less. These polyol compounds are usually contained in the curable epoxy resin composition in a proportion of 50% by weight or less, preferably 30% by weight or less.

  Furthermore, in the curable epoxy resin composition, other additives such as an ion trap agent, an antioxidant, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, unless the adhesiveness is impaired. Fillers, flow regulators, plasticizers, antifoaming agents, and the like can be blended. Examples of the ion trapping agent include powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based and mixed inorganic compounds. Examples of the antioxidant include hinders. Examples include dophenol antioxidants.

  After the adhesive comprising the curable epoxy resin composition containing the epoxy compound as described above was applied to the adhesive surface of the polarizing film or the transparent protective film, or both adhesive surfaces, the adhesive was applied. Bonding on the surface, irradiating with active energy rays or heating, the uncured adhesive layer is cured, and the polarizing film and the transparent protective film are composed of a cured product layer of a curable epoxy resin composition It can be bonded via an adhesive layer. As an adhesive coating method, for example, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater are adopted.

  The adhesive composed of the curable epoxy resin composition can basically be used as a solventless adhesive that does not substantially contain a solvent component, but each coating method has an optimum viscosity range. Therefore, a solvent may be included for viscosity adjustment. It is preferable to use a solvent that dissolves the epoxy resin composition well without degrading the optical performance of the polarizing film. For example, hydrocarbons represented by toluene, esters represented by ethyl acetate, and the like. And organic solvents such as

When the adhesive is cured by irradiation with active energy rays, the light source used is not particularly limited. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp having a light emission distribution at a wavelength of 400 nm or less. , Black light lamps, microwave excited mercury lamps, metal halide lamps and the like. The light irradiation intensity to the curable epoxy resin composition may vary depending on the composition, but the irradiation intensity in the wavelength region effective for activating the photocationic polymerization initiator is 0.1 to 100 mW / cm ^2. Is preferred. When the light irradiation intensity to the curable epoxy resin composition is less than 0.1 mW / cm ² , the reaction time becomes too long, and when it exceeds 100 mW / cm ² , the heat radiated from the lamp and the curable epoxy resin composition The heat generated during polymerization of the product may cause yellowing of the curable epoxy resin composition or deterioration of the polarizing film. The light irradiation time to the curable epoxy resin composition is controlled for each composition and is not particularly limited, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 5, It is preferably set to be 000 mJ / cm ² . When the integrated light quantity to the curable epoxy resin composition is less than 10 mJ / cm ² , the generation of active species derived from the photocationic polymerization initiator is not sufficient, and the adhesive may be insufficiently cured. On the other hand, if the integrated light quantity exceeds 5,000 mJ / cm ² , the irradiation time becomes very long, which may be disadvantageous for improving productivity.

  When the adhesive is cured by heat, it can be heated by a generally known method, and the conditions are not particularly limited, but usually the thermal cationic polymerization compounded in the curable epoxy resin composition is started. Heating is performed at a temperature equal to or higher than the temperature at which the agent generates cationic species and Lewis acid, and the specific heating temperature is, for example, about 50 to 200 ° C.

  In the range where the polarization degree, transmittance and hue of the polarizing film, transparency and retardation properties of the transparent protective film, and various functions of the polarizing plate are not deteriorated even when cured under the irradiation of active energy rays or heating. It is preferable to cure.

[Coating type transparent protective layer]
As shown in FIG. 4, a mode in which a coating-type transparent protective layer 28 is provided on the surface of the polarizing film 21 on the liquid crystal cell side, and a first side on the side far from the liquid crystal cell of the polarizing film 21 as in the example shown in FIG. The coating-type transparent protective layer 27 is provided, and the second coating-type transparent protective layer 28 is provided on the liquid crystal cell side of the polarizing film 21 (the same applies to the backlight-side polarizing plate 30). The layers 27 and 28 are made of a cured product of a curable resin composition containing a curable compound that can be cured by irradiation with active energy rays or heating. By forming at least one of the transparent protective layers in the polarizing plate from a curable resin composition, the resulting polarizing plate can be reduced in thickness and weight. The active energy ray is a concept including, for example, ultraviolet rays, visible light, electron beams, X-rays, and the like, as described above with respect to an example of a preferable adhesive for bonding the polarizing film and the transparent protective film. .

  The curable compound may be a cationic polymerizable curable compound or a radical polymerizable curable compound. Examples of the cationic polymerizable curable compound include an epoxy compound having at least one epoxy group in the molecule, an oxetane compound having at least one oxetane ring in the molecule, and the like. Examples of radically polymerizable curable compounds include (meth) acrylic compounds having at least one (meth) acryloyloxy group in the molecule. Such a curable resin composition containing a curable compound is cured by irradiation with active energy rays or heating to give a transparent protective layer excellent in transparency, mechanical strength, thermal stability and the like. When providing a coating-type transparent protective layer on both surfaces of the polarizing film as shown in FIG. 5, a curable resin composition for forming the first coating-type transparent protective layer 27 on the side far from the liquid crystal cell; The curable resin composition for forming the second coating-type transparent protective layer 28 on the liquid crystal cell side may be the same or a different composition, but from the viewpoint of manufacturing efficiency. Are preferably the same curable resin composition.

Coating type transparent protective layer formed by curing the curable resin composition as described above, since most do not exhibit optical anisotropy, any retardation R _th in-plane retardation R _e and the thickness direction Can also be close to zero. Here, the retardation R _th and the in-plane retardation R _e in the thickness direction is represented by the formula described for the case of using the transparent protective film to each destination (a) and Formula (b). Coating type transparent protective layer 28, particularly the liquid crystal cell side, similarly to the description given for the case of using the transparent protective film previously, to better its plane retardation R _e is preferably small, the retardation R _th in the thickness direction The closer to zero, the better. Specifically, the in-plane retardation R _e with respect to light having a wavelength of 590nm is preferably 10nm or less, and more preferably 5nm or less. Also, the retardation R _th in the thickness direction for light at a wavelength of 590nm is preferably in the range of -25～25Nm, and more preferably in the range of -10～10Nm. The retardation of the coating type transparent protective layer is obtained by forming a cured layer of a curable resin composition on a peelable film such as a polyethylene terephthalate film and then removing the peelable film. A cured product layer of the resin composition may be used as a measurement sample.

By the retardation value R _th in-plane retardation R _e and the thickness direction of the coating-type transparent protective layer 28 of the liquid crystal cell side in the above range, when pasted polarizing plate to the liquid crystal cell obtained crystal Light leakage at the time of black display in the display device can be effectively prevented.

  The curable resin composition for forming the coating-type transparent protective layers 27 and 28 preferably contains an epoxy compound as a curable compound that can be cured by irradiation with active energy rays or heating. Thereby, the coating type transparent protective layer which shows favorable adhesiveness with respect to a polarizing film and an adhesive layer can be obtained. As described above, this epoxy compound only needs to have at least one epoxy group in the molecule, but usually an adhesive for bonding the polarizing film and the transparent protective film described above. It is preferable that the molecule has at least two epoxy groups in the molecule as in the case of the epoxy compound that constitutes.

  In the curable resin composition, it is preferable to use an epoxy compound containing no aromatic ring in the molecule as a main component from the viewpoints of weather resistance, refractive index, cationic polymerizability and the like. Examples of such an epoxy compound that does not contain an aromatic ring in the molecule include a hydrogenated epoxy compound, an aliphatic epoxy compound, and an alicyclic epoxy compound. About these epoxy compounds, the description similar to the epoxy compound which comprises the adhesive agent for bonding the polarizing film mentioned above and a transparent protective film is applied. Also in the curable resin composition for forming the coating type transparent protective layers 27 and 28, the epoxy compound can be used alone or in combination of two or more.

  In the curable resin composition used for forming the coating-type transparent protective layers 27 and 28, the epoxy compound is preferably contained in a proportion of 30 to 100% by weight based on the entire curable compound. More preferably, it is contained in a proportion of wt%, further 40-60 wt%. When content of the epoxy compound in a curable compound is less than 30 weight%, adhesiveness with a polarizing film may fall.

  This curable resin composition can also contain an oxetane compound in addition to the epoxy compound. By adding an oxetane compound, the viscosity of the curable resin composition can be lowered and the curing speed can be increased. The oxetane compound is a compound having at least one oxetane ring in the molecule, that is, a 4-membered ether structure, and its specific example also constitutes an adhesive for pasting a polarizing film and a transparent protective film first. Examples of the curable resin composition to be used include those exemplified as those that can be used in combination with the epoxy compound. Although the compounding quantity of an oxetane compound is not restrict | limited in particular, Usually, it is 30 weight% or less on the basis of the whole curable compound, and 10 to 25 weight% is preferable.

  When the curable resin composition used for forming the coating-type transparent protective layers 27 and 28 contains a cationically polymerizable curable compound such as an epoxy compound or an oxetane compound, the curable resin composition contains a photocationic cation. It is preferable to blend a polymerization initiator. When a cationic photopolymerization initiator is used, it becomes possible to form a coating-type transparent protective layer at room temperature, so the need to consider the heat resistance of the polarizing film or distortion due to expansion is reduced, and the transparent protective layer is polarized with good adhesion. It can be formed on a film. Moreover, since a photocationic polymerization initiator acts catalytically by light, it is excellent in storage stability and workability even when mixed with a curable resin composition. For the cationic photopolymerization initiator, the same explanation as described above can be applied to the curable resin composition constituting the adhesive for pasting the polarizing film and the transparent protective film. Also in the curable resin composition used for forming the coating-type transparent protective layers 27 and 28, the photocationic polymerization initiator may be used alone or in combination of two or more. . Among them, the aromatic sulfonium salt has an ultraviolet absorption property even in a wavelength region of 300 nm or more, and thus can provide a cured product having excellent curability and good mechanical strength and good adhesion to a polarizing film. Therefore, it is preferably used.

  The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of total amounts of cation polymerizable curable compounds, such as an epoxy compound and an oxetane compound, and is 1-6 weight. Part is preferred. When the blending amount of the photocationic polymerization initiator is less than 0.5 parts by weight with respect to 100 parts by weight of the total amount of the cation polymerizable curable compound, curing becomes insufficient, and mechanical strength and a transparent protective layer There exists a tendency for adhesiveness with a polarizing film to fall. On the other hand, if the amount of the cationic photopolymerization initiator exceeds 20 parts by weight with respect to 100 parts by weight of the total amount of the cationic polymerizable curable compound, the amount of ionic substances in the cured product increases, and There is a possibility that the hygroscopicity is increased and the durability of the transparent protective layer is lowered.

  Moreover, it is preferable that the curable resin composition used for formation of a transparent protective layer contains the (meth) acrylic-type compound which is radically polymerizable with the said epoxy compound or an epoxy compound and an oxetane compound. By using a (meth) acrylic compound in combination, a transparent protective layer having high hardness, excellent mechanical strength, and higher durability can be obtained. Furthermore, adjustments such as the viscosity of the curable resin composition, the curing rate, the surface curability of the resulting transparent protective layer, and the adhesion to the polarizing film can be more easily performed.

  The (meth) acrylic compound is a compound having a (meth) acryloyloxy group in the molecule, and a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule or a functional group-containing compound. And (meth) acrylate oligomers having at least two (meth) acryloyloxy groups in the molecule. These may be used alone or in combination of two or more. When using 2 or more types together, 2 or more types of (meth) acrylate monomers may be sufficient, 2 or more types of (meth) acrylate oligomers may be sufficient, and 1 or more types of (meth) acrylate monomers may be used. One or more (meth) acrylate oligomers may be used in combination.

  The (meth) acrylate monomer includes a monofunctional (meth) acrylate monomer having one (meth) acryloyloxy group in the molecule and a bifunctional (meth) having two (meth) acryloyloxy groups in the molecule. There are acrylate monomers and polyfunctional (meth) acrylate monomers having 3 or more (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, 2-hydroxybutyl (meth) acrylate 2-hydroxy-3-phenoxypropyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, Benzyl (meth) acrylate, isobornyl (meth) acrylate, phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate Rate, ethyl carbitol (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate, etc. phenoxy polyethylene glycol (meth) acrylate.

  Moreover, the monofunctional (meth) acrylate monomer containing a carboxyl group may be used. Examples thereof include 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, carboxyethyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid, N- ( Examples include meth) acryloyloxy-N ′, N′-dicarboxymethyl-p-phenylenediamine, 4- (meth) acryloyloxyethyl trimellitic acid, and the like.

  Bifunctional (meth) acrylate monomers include alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, aliphatic polyol di (meth) acrylates Di (meth) acrylates of hydrogenated dicyclopentadiene or tricyclodecane dialkanol, di (meth) acrylates of dioxane glycol or dioxane dialkanol, di (meth) of alkylene oxide adducts of bisphenol A or bisphenol F Representative examples include acrylates and bisphenol A or bisphenol F epoxy di (meth) acrylates.

  More specific examples of the bifunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, ditrimethylol Propane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, silicone di (meth) acrylate, hydroxypivalate ester neopentyl glycol di (meth) acrylate, 2,2-bis [4- (Meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclodecandi Methanol di (meth) acrylate, 1,3-dioxane-2,5-diyl di (meth) acrylate [also known as dioxane glycol di (meth) acrylate], hydroxypivalaldehyde and trimethylol group Di (meth) acrylate, tris (hydroxyethyl) of acetal compound [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] with bread ) Isocyanurate di (meth) acrylate and the like.

  The trifunctional or higher polyfunctional (meth) acrylate monomers include glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol. Tri- or higher functional aliphatic such as tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate Poly (meth) acrylates of polyols are typical ones. Besides, poly (meth) acrylates of tri- or higher functional halogen-substituted polyols, alkylene of glycerol Tri (meth) acrylates of xoxide adducts, tri (meth) acrylates of trimethylolpropane alkylene oxide adducts, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate Examples include tri (meth) acrylates and silicone hexa (meth) acrylate.

  The (meth) acrylate oligomer which is another kind of (meth) acrylic compound includes urethane (meth) acrylate oligomer, polyester (meth) acrylate oligomer, epoxy (meth) acrylate oligomer and the like.

  The urethane (meth) acrylate oligomer is a compound having a urethane bond (—NHCOO—) and at least two (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 the molecule and a polyisocyanate, and polyols Urethane reaction product of terminal isocyanate group-containing urethane compound obtained by reaction with isocyanate, and (meth) acrylate monomer each having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule, etc. Is mentioned.

  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) acrylate, and 2-hydroxy-3- Examples include phenoxypropyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate.

  Examples of the polyisocyanate used for the urethanation reaction with these hydroxyl group-containing (meth) acrylate monomers include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and aromatic of these diisocyanates. Di- or tri-isocyanates such as diisocyanates obtained by hydrogenating isocyanates (eg, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.), triphenylmethane triisocyanate, and dibenzylbenzene triisocyanate, And polyisocyanate obtained by increasing the amount of diisocyanate.

  In addition to aromatic, aliphatic, and alicyclic polyols, polyester polyols, polyether polyols, and the like are used as polyols used to obtain terminal isocyanate group-containing urethane compounds by reaction with polyisocyanates. You can also.

  Aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylol ethane, trimethylol propane, ditriol. Examples include methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

  The polyester polyol is obtained by a dehydration condensation reaction between the above polyols and a polybasic carboxylic acid or an anhydride thereof. Polybasic carboxylic acids or their anhydrides include (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) Examples include phthalic acid, isophthalic acid, terephthalic acid, hexahydro (anhydride) phthalic acid, and the like. Here, the expression “(anhydrous)” means that there can be both a state without it and a state with “anhydrous”, and the same applies to the following. For example, “(anhydrous) succinic acid” means that there can be both succinic acid and succinic anhydride.

  The polyether polyol includes polyoxyalkylene-modified polyol obtained by reaction of the above polyols or dihydroxybenzenes with alkylene oxide, in addition to polyalkylene glycol.

  The polyester (meth) acrylate oligomer is a compound having an ester bond and at least two (meth) acryloyloxy groups in the molecule. Specifically, it can be obtained by dehydration condensation reaction of (meth) acrylic acid, polybasic carboxylic acid or anhydride thereof, and polyol. Polybasic carboxylic acids or anhydrides used in the dehydration condensation reaction include (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyrone Examples include merit acid, hexahydro (anhydride) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, and terephthalic acid. 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, trimethylol ethane, trimethylol propane, Examples include ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

  The epoxy (meth) acrylate oligomer can be obtained by 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 for the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and diglycidyl ether of bisphenol A. .

  Among the (meth) acrylic compounds described above, the compound having the structure represented by the following formula (XI) or (XII) gives a high elastic modulus to the cured product, and is also a cationically polymerizable curable compound, particularly a fat. When combined with a cyclic epoxy compound, a transparent protective layer having excellent adhesion to the polarizing film is obtained, which is preferable.

In the formula, Q ₁ and Q ₂ each 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 carbon. The hydrocarbon group of number 1-10 is represented.

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 has 1 to 10 carbon atoms. Generally, about 1 to 6 carbon atoms are sufficient. In the formula (XII), when Q ₃ is a hydrocarbon group, it may be linear or branched, and can typically be an alkyl group. In this case, it is generally sufficient for the alkyl group to have about 1 to 6 carbon atoms.

The compound represented by the formula (XI) is a di (meth) acrylate derivative of hydrogenated dicyclopentadiene or tricyclodecane dialkanol, and specific examples thereof are those exemplified above. Cyclopentadienyl di (meth) acrylate [in formula (XI), Q ₁ = Q ₂ = (meth) acryloyloxy group compound], tricyclodecane dimethanol di (meth) acrylate [in formula (XI), Q ₁ = Q ₂ = (meth) acryloyloxymethyl group compound] and the like.

Further, the compound represented by the formula (XII) is a di (meth) acrylate derivative of dioxane glycol or dioxane dialkanol, and specific examples thereof include those exemplified above, but 1,3-dioxane- 2,5-diyl di (meth) acrylate [also known as dioxane glycol di (meth) acrylate, compound of formula (XII), Q ₁ = Q ₂ = (meth) acryloyloxy group, Q ₃ = H], hydroxypival Acetal compound of aldehyde and trimethylolpropane [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] di (meth) acrylate [ in the formula (XII), Q ₁ = (meth) acryloyloxy methyl group, Q ₂ = 2- (meth) acryloyl 1,1-dimethylethyl group, the compound of Q ₃ = ethyl group], and the like.

  In the curable resin composition used for forming the coating-type transparent protective layer, the content of the (meth) acrylic compound is preferably 70% by weight or less, more preferably 35 to 70% by weight, based on the entire curable compound. Preferably, 40 to 60% by weight is more preferable. If the content of the (meth) acrylic compound exceeds 70% by weight, the adhesion with the polarizing film may be lowered.

  When the curable resin composition contains the (meth) acrylic compound as described above, it is preferable to add a radical photopolymerization initiator to the curable resin composition. The radical photopolymerization initiator is not particularly limited as long as it can initiate polymerization of a radically polymerizable curable compound such as a (meth) acrylic compound by irradiation with active energy rays, and a conventionally known one can be used. . Specific examples of the photo radical polymerization initiator include acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [Acetophenone-based initiators such as 4- (methylthio) phenyl-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone, and 4 Benzophenone initiators such as 4,4'-diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; other xanthone, fluorenone, camphorquinone Lens aldehyde, such as anthraquinone, and the like.

  The compounding quantity of radical photopolymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of (meth) acrylic-type compounds, and 1-6 weight part is preferable. When the blending amount of the radical photopolymerization initiator is less than 0.5 parts by weight with respect to 100 parts by weight of the (meth) acrylic compound, curing becomes insufficient, and the mechanical strength of the transparent protective layer and the transparent protective layer and polarized light Adhesion with the film may decrease. Moreover, when the compounding quantity of radical photopolymerization initiator exceeds 20 weight part with respect to 100 weight part of (meth) acrylic-type compounds, the durable performance of a transparent protective layer may fall.

  The curable resin composition for forming a coating-type transparent protective layer can further contain a photosensitizer as necessary. By using a photosensitizer, the reactivity of cationic polymerization or radical polymerization is improved, and the mechanical strength of the transparent protective layer and the adhesion between the transparent protective layer and the polarizing film can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. Specific examples of photosensitizers include benzoin methyl ether, benzoin isopropyl ether, and benzoin derivatives such as α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, o-benzoylbenzoate Benzophenones such as methyl acid, 4,4′-bis (dimethylamino) benzophenone, and 4,4′-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; 2-chloroanthraquinone And anthraquinone derivatives such as 2-methylanthraquinone; acridone derivatives such as N-methylacridone and N-butylacridone; other α, α-diethoxyacetophenone, benzyl, fluorenone, Xanthone, uranyl compound, halogen compound and the like can be mentioned. These may be used alone or in combination of two or more. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the curable compound.

  Moreover, the curable resin composition may contain an antistatic agent for imparting antistatic performance to the polarizing plate. The kind of antistatic agent is not particularly limited, and various known antistatic agents can be used. For example, cationic surfactants such as acyloylamidopropyldimethylhydroxyethylammonium nitrate, acyloylamidopropyltrimethylammonium sulfate, and cetylmorpholium methosulfate; linear alkyl potassium potassium salt, polyoxyethylene alkyl phosphorus Anionic surfactants such as acid potassium salts and alkane sulfonates; nonionics such as N, N-bis (hydroxyethyl) -N-alkylamines, fatty acid ester derivatives thereof, and polyhydric alcohol fatty acid partial esters And surface active agents. The blending ratio of the antistatic agent is appropriately determined according to desired characteristics, but is usually about 0.1 to 20 parts by weight with respect to 100 parts by weight of the curable compound.

  The curable resin composition can be blended with known polymer additives that are usually used for polymers. Examples include primary antioxidants such as phenols and amines, sulfur secondary antioxidants, hindered amine light stabilizers (HALS), benzophenone, benzotriazole, and benzoate UV absorbers. It is done.

  Silica fine particles may be added to the curable resin composition. By adding silica fine particles, the hardness and mechanical strength of the obtained transparent protective layer can be further improved. The silica fine particles can be blended in the curable resin composition in the form of a liquid dispersed in an organic solvent, for example. The silica fine particles may have reactive functional groups such as hydroxyl groups, epoxy groups, (meth) acryloyl groups, and vinyl groups on the surface. The particle size of the silica fine particles is usually 100 nm or less, preferably about 5 to 50 nm. When the particle diameter of the fine particles exceeds 100 nm, the transparency of the transparent protective layer may be lowered.

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

  Examples of silica fine particles dispersed in a commercially available organic solvent include, for example, “methanol silica sol” (manufactured by Nissan Chemical Industries, Ltd., silica particle size of 10 to 15 nm, solid content of 30% by weight). ), “MA-ST-M” (manufactured by Nissan Chemical Industries, Ltd., silica particle size 20 to 25 nm, solid content 40% by weight), and “OSCAL 1132” (manufactured by Catalyst Chemical Industries, Ltd., silica particle size 10 to 20 nm) "OSCAL 1232" (catalyst chemical industry Co., Ltd., silica particle size 10 to 20 nm, solid content 30 to 31% by weight); organic solvent is n- "OSCAL 1332" which is propyl alcohol (manufactured by Catalytic Chemical Industry Co., Ltd., silica particle size 10-20 nm, solid content 30-31 ”;“ IPA-ST ”(manufactured by Nissan Chemical Industries, silica particle size 10-15 nm, solid content 30% by weight), and“ OSCAL 1432 ”(manufactured by Catalytic Chemical Industries, silica "NBA-ST" whose organic solvent is n-butyl alcohol (manufactured by Nissan Chemical Industries, silica particle size of 10-15 nm, solid content of 20% by weight) , And “OSCAL 1532” (manufactured by Catalyst Kasei Kogyo Co., Ltd., silica particle size 10 to 20 nm, solid content 30 to 31 wt%); “EG-ST” (manufactured by Nissan Chemical Industries, Ltd.) whose organic solvent is ethylene glycol "OSCAL 1632" (Catalytic Chemical Industry Co., Ltd.) whose organic solvent is ethyl cellosolve “NPC-ST” (manufactured by Nissan Chemical Industries, Ltd., silica particle size 10-15 nm, silica particle size 10-20 nm, solid content 30-31 wt%); “DMAC-ST” (manufactured by Nissan Chemical Industries, silica particle size 10 to 15 nm, solid content 20% by weight), and “DMAC-ST-ZL” (solid content 30% by weight); “XBA-ST” (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter, organic solvent is a mixture of xylene and n-butyl alcohol) "MIBK-ST" (manufactured by Nissan Chemical Industries, Ltd., silica particle size) whose organic solvent is methyl isobutyl ketone "MEK-ST" (manufactured by Nissan Chemical Industries, silica particle size 10-15 nm, solid content 30% by weight), "SP-1120" (10-15 nm, solid content 30% by weight); Manufactured by Konishi Chemical Co., Ltd., silica particle size 15-20 nm, solid content 5-10 wt%), and “SP-6120” (manufactured by Konishi Chemical Industry Co., Ltd., silica particle size 15-20 nm, solid content 5-10 wt%) %) And the like, and one or more of these can be suitably used. Further, “Snowtex 20” (manufactured by Nissan Chemical Industries, silica particle size 10-20 nm), “Snowtex C” (manufactured by Nissan Chemical Industries, silica particle size 10-20 nm), etc., in which the dispersion medium is water, etc. Can also be used.

  The amount of the silica fine particles added is preferably 5 to 250 parts by weight, more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the curable compound contained in the curable resin composition. When the addition amount of the silica fine particles is less than 5 parts by weight with respect to 100 parts by weight of the curable compound, the improvement in the hardness of the transparent protective layer due to the addition of the silica fine particles may not be sufficient. On the other hand, when the addition amount of the silica fine particles exceeds 250 parts by weight with respect to 100 parts by weight of the curable compound, the adhesion between the polarizing film and the transparent protective layer is lowered, or the dispersion of the silica fine particles in the curable resin composition In some cases, the stability may decrease, or the viscosity of the curable resin composition may increase excessively.

  The curable resin composition may contain a solvent as necessary. The solvent is appropriately selected depending on the solubility of the components constituting the curable resin composition. Commonly used solvents include aliphatic or alicyclic 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; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; methylene chloride, chloroform, and the like And halogenated hydrocarbons. The blending ratio of the solvent is appropriately determined from the viewpoint of adjusting the viscosity depending on the processing purpose such as film formability.

  When the curable resin composition is applied onto a polarizing film or a substrate, if the coating property on the polarizing film or the substrate is poor or the surface properties of the cured product of the curable resin composition are not sufficient In order to improve them, a leveling agent can be added to the curable resin composition. As the leveling agent, various compounds such as silicone series, fluorine series, polyether series, acrylic acid copolymer series and titanate series can be used. These leveling agents may be used alone or in combination of two or more.

  The addition amount of the leveling agent is preferably 0.01 to 1 part by weight, more preferably 0.1 to 0.7 part by weight, especially 100 parts by weight of the curable compound contained in the curable resin composition. 0.2-0.5 weight part is more preferable. When the amount of the leveling agent added is less than 0.01 parts by weight with respect to 100 parts by weight of the curable compound, there may be cases where the improvement of paintability and surface properties is not sufficient. When the addition amount of a leveling agent exceeds 1 weight part with respect to 100 weight part of curable compounds, the adhesiveness of a polarizing film and a transparent protective layer may fall.

  In the form in which the coating type transparent protective layers 27 and 28 are provided on both surfaces of the polarizing film 21 as shown in FIG. 5, when the polarizing plate is the viewing side of the liquid crystal display device, the first side which is the side far from the liquid crystal cell. The curable resin composition for forming the coating-type transparent protective layer 27 may contain an antiglare material so that the polarizing plate has an antiglare function. As the antiglare material, cross-linked acrylic resin beads are preferably used. Cross-linked acrylic resin beads are acrylic monomers such as acrylic acid, alkyl acrylate ester, aryl acrylate ester, methacrylic acid, alkyl methacrylate ester, aryl methacrylate ester, acrylamide, or acrylonitrile, polymerization initiators such as persulfuric acid, In addition, it is a substantially spherical product composed of a crosslinked product of a polymer and a copolymer obtained by polymerizing by a suspension polymerization method using a crosslinkable compound such as ethylene glycol di (meth) acrylate. Particularly preferred are those prepared using acrylic monomers mainly composed of methyl methacrylate. Cross-linked acrylic resin beads have a spherical or almost spherical shape and do not exhibit oil absorption. Therefore, when used for roughening layers (layers with irregularities on the surface), they exhibit excellent stain resistance. Can do. These crosslinked acrylic resin beads are surface-modified with organic or inorganic materials such as fats and oils, silane coupling agents and metal oxides in order to improve dispersibility in the curable resin composition. It may be.

  The crosslinked acrylic resin beads preferably give a particle size distribution such that particles having a particle size in the range of 0.5 to 6 μm are 60% by weight or more and particles having a particle size exceeding 6 μm are less than 20% by weight. Furthermore, it is more preferable to provide a particle size distribution in which particles having a particle size in the range of 0.5 to 6 μm are 80% by weight or more and particles having a particle size exceeding 6 μm are less than 10% by weight. When particles having a particle size in the range of 0.5 to 6 μm are less than 60% by weight or particles having a particle size exceeding 6 μm are 20% by weight or more, a polarizing plate is used in the liquid crystal display device. When applied, it may cause glare on the screen. Further, when the particles having a particle diameter in the range of 0.5 to 6 μm are less than 60% by weight and the particles having a particle diameter exceeding 6 μm are 20% by weight or more, glare occurs and the screen is prevented. Dazzle is also worse.

  The blending amount of the crosslinked acrylic resin beads is preferably in the range of 0.5 to 30% by weight and more preferably in the range of 1 to 15% by weight in the total solid content of the curable resin composition. When the blending amount is less than 0.5% by weight, the effect of improving the antiglare property becomes insufficient. When the blending amount exceeds 30% by weight, the wear resistance and environmental resistance of the roughened layer, etc. The durability of the deteriorated.

  The haze value of the coating-type transparent protective layer imparted with antiglare property is preferably in the range of 6 to 45%. When the haze value of the antiglare transparent protective layer is less than 6%, a sufficient antiglare effect may not appear. On the other hand, when the haze value exceeds 45%, when the polarizing plate is applied to a liquid crystal display device, the screen may be whitened and image quality may be deteriorated.

  The haze value can be measured using a commercially available haze meter in accordance with JIS K 7136 as described above for the transparent protective film. When measuring the haze value of the coating-type transparent protective layer, after forming a cured product of the curable resin composition on a peelable film such as a polyethylene terephthalate film, curing obtained by peeling the peelable film In order to prevent warpage of the cured product layer, it is preferable to use, for example, a measurement sample in which an optically transparent adhesive is bonded to a glass substrate.

  On the first coating type transparent protective layer formed on the side far from the liquid crystal cell, a functional layer such as a conductive layer, a hard coat layer, and a low reflection layer may be provided regardless of the viewing side or the backlight side. it can. As the curable resin composition for forming the coating-type transparent protective layer, a resin composition capable of forming a layer having these functions can also be selected.

  The thickness of the coating-type transparent protective layer is preferably in the range of 0.1 to 10 μm, and more preferably 1 to 5 μm. When the thickness of the coating type transparent protective layer is less than 0.1 μm, the durability of the transparent protective layer may be insufficient. If the thickness exceeds 10 μm, the effect of reducing the thickness and weight of the polarizing plate is reduced.

[Adhesive layer]
The pressure-sensitive adhesive layers 40, 50 are provided on the surface of the polarizing plate to be bonded to the liquid crystal cell, that is, on the surface of the transparent protective film 26, 36 on the liquid crystal cell side of the polarizing plate 20, 30, or the coating type transparent protective layer 28. Is provided. The pressure-sensitive adhesive layers 40 and 50 are for bonding the polarizing plates 20 and 30 to the liquid crystal cell 10.

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited as long as it has excellent optical transparency and exhibits pressure-sensitive adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness. It is done. Specifically, as the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive containing an acrylic resin (acrylic pressure-sensitive adhesive) can be mentioned.

  As the acrylic resin contained in the acrylic pressure-sensitive adhesive, a resin mainly composed of an acrylic ester such as butyl acrylate, ethyl acrylate, isooctyl acrylate, and 2-ethylhexyl acrylate is preferably used. This acrylic resin is usually copolymerized with a polar monomer. The polar monomer is a compound having a polymerizable unsaturated bond and a polar functional group, wherein the polymerizable unsaturated bond can be derived from a (meth) acryloyl group, and the polar functional group is It may be a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, or the like. Specific examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, 2-N, N-dimethylaminoethyl ( Examples include meth) acrylate and glycidyl (meth) acrylate.

  The acrylic resin that is the main component of such an adhesive preferably has a glass transition temperature of 25 ° C. or lower, more preferably 0 ° C. or lower, in order to exhibit excellent adhesiveness. Moreover, the weight average molecular weight (standard polystyrene conversion) is 100,000 or more normally.

  The pressure-sensitive adhesive usually contains a crosslinking agent together with an acrylic resin. Various other additives may be blended. Suitable additives include silane coupling agents and antistatic agents. A silane coupling agent is effective in increasing the adhesive strength with glass. Antistatic agents are effective in reducing or preventing the generation of static electricity.

  Generally, when sticking a polarizing plate to a liquid crystal cell through an adhesive layer, the surface protective film (separator) that has been temporarily protected by covering the adhesive layer is peeled off and then attached to the liquid crystal cell. In some cases, the static electricity generated when the surface protective film is peeled off causes alignment failure of the liquid crystal in the liquid crystal cell, and this phenomenon may cause display failure of the IPS mode liquid crystal display device. As a means for reducing or preventing the generation of static electricity, it is effective to add an antistatic agent to the adhesive.

  The pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive used in the present invention preferably has a storage elastic modulus at 23 ° C. of 0.15 to 10 MPa, and preferably has an adhesive strength to glass of 1 to 30 N / 25 mm. .

  Storage elastic modulus (dynamic elastic modulus) is a commonly used term for viscoelasticity measurement, and is generated by applying strain or stress that changes (vibrates) over time to a sample. This is a value obtained by measuring the mechanical properties of a sample by measuring stress or strain (dynamic viscoelasticity measurement). The strain is a component of the phase that is 90 degrees out of phase with the stress component. When divided into waves, the elastic modulus is calculated from the strain in phase with the stress.

  By using a pressure-sensitive adhesive layer having a storage elastic modulus in the above range, it is possible to reduce the dimensional change caused by the shrinkage of the polarizing film generated under an environment where the high temperature environment and the low temperature environment are repeated. A liquid crystal display device can be obtained. The storage elastic modulus generally decreases with increasing temperature, but it is more preferable to exhibit a high storage elastic modulus of 0.15 MPa or higher even at a high temperature of about 80 ° C., for example.

  Moreover, the adhesive force with respect to glass sticks the polarizing plate in which the adhesive layer was provided to glass on the adhesive layer side, and after leaving it at room temperature (23 degreeC) for 24 hours, it uses a dynamic viscoelasticity measuring apparatus. The value to be measured. If the adhesive force with respect to glass is in the above range, the polarizing plate can be easily peeled off when an operation for re-attaching the polarizing plate to the liquid crystal cell is required. In consideration of such peelability (also referred to as reworkability) from the liquid crystal cell, the adhesive strength of the adhesive layer to the glass is more preferably in the range of 1 to 10 N / 25 mm. By using such a pressure-sensitive adhesive layer, it is possible to suppress the phenomenon in which bubbles or the like are generated between the liquid crystal cell and the polarizing plate (transparent protective film or coating-type transparent protective layer on the liquid crystal cell side). it can.

  The pressure-sensitive adhesive layers 40 and 50 are formed by directly applying a pressure-sensitive adhesive solution obtained by dissolving the above-described pressure-sensitive adhesive component in an organic solvent to a transparent protective film or a coating-type transparent protective layer constituting a polarizing plate, thereby removing the organic solvent. Then, apply the above-mentioned adhesive solution on the surface protection film (separator) in advance by applying a surface protection film (separator) on it, and remove the solvent to form an adhesive layer. In addition, it can be provided on the polarizing plate by, for example, a transfer method in which this is attached to the polarizing plate. The thickness of the pressure-sensitive adhesive layer can be about 1 to 50 μm, but is preferably about 10 to 30 μm from the viewpoint of thinning the liquid crystal display device while expressing an appropriate adhesive force.

  The liquid crystal panel 60 can be obtained by bonding the polarizing plate to both surfaces of the liquid crystal cell via the pressure-sensitive adhesive layer. When the transparent protective film which provided the anti-glare property to the polarizing plate, or the coating type transparent protective layer was formed, the polarizing plate is bonded by the visual recognition side of a liquid crystal cell. The liquid crystal display device of the present invention is manufactured by combining the liquid crystal panel 60 and the backlight 70 with a conventionally known configuration. Various known optical members such as a light collecting sheet, a diffusion film, a light guide plate, and a light reflecting sheet may be disposed between the liquid crystal panel and the backlight.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not prescribed | regulated by these examples. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified. The evaluation methods used in the following examples are as follows.

(1) Measuring method of thickness:
Measurement was performed using a digital micrometer “MH-15M” manufactured by Nikon Corporation.

(2) plane retardation R _e and the thickness direction retardation R _th measurement methods:
Using “KOBRA-21ADH” manufactured by Oji Scientific Instruments, which is a phase difference meter based on the parallel Nicol rotation method, the in-plane retardation R _e and the thickness direction retardation R _th at a wavelength of 590 nm at 23 ° C. It was measured.

(3) Measuring method of storage elastic modulus:
The storage elastic modulus (G ′) of the pressure-sensitive adhesive layer was measured according to the following (I) to (III).
(I) Two samples of 25 ± 1 mg are taken out from the pressure-sensitive adhesive layer, and each is formed into a substantially ball shape.
(II) The two samples obtained in (I) above are attached to the upper and lower surfaces of the I-shaped jig, and the upper and lower surfaces are sandwiched between the L-shaped jigs. The configuration of the measurement sample is L-shaped jig / adhesive / I-shaped jig / adhesive / L-shaped jig.
(III) The storage elastic modulus (G ′) of the thus prepared sample was measured using a dynamic viscoelasticity measuring device (“DVA-220” manufactured by IT Measurement Control Co., Ltd.) at a temperature of 23 ° C., a frequency of 1 Hz, and an initial value. The measurement was performed under the condition of strain 1N.

(4) Measuring method of adhesive strength of adhesive layer to glass:
The polarizing plate provided with the pressure-sensitive adhesive layer is cut to a width of 25 mm, bonded to a glass plate on the pressure-sensitive adhesive layer side, subjected to pressure treatment for 20 minutes under conditions of a temperature of 50 ° C. and a pressure of 5 atmospheres, and then 23 After leaving still at 1 ° C. for 1 day, using a test machine “AZ1” manufactured by Shimadzu Corporation, in the length direction of the cut polarizing plate in accordance with JIS Z 0237 and 180 ° direction from the glass surface ( The stress was measured when it was folded and peeled in a direction parallel to the glass surface.

[Production Example 1] (Preparation of aqueous adhesive)
3 parts of carboxyl group-modified polyvinyl alcohol (“KL-318” manufactured by Kuraray Co., Ltd.) is dissolved in 100 parts of water, and further, a polyamide epoxy additive which is a water-soluble epoxy resin (manufactured by Sumika Chemtex Co., Ltd.) 1.5 parts of “Smilease Resin 650 (30)”, an aqueous solution having a solid content of 30%) was added to prepare an aqueous adhesive.

[Production Example 2] (Preparation of photocurable adhesive)
100 parts of bis (3,4-epoxycyclohexylmethyl) adipate, 25 parts of diglycidyl ether of hydrogenated bisphenol A, and 4,4′-bis (diphenylsulfonio) diphenyl sulfide bis (hexafluoro) as a photocationic polymerization initiator Phosphate) 2.2 parts were mixed and then defoamed to prepare an adhesive composed of a curable epoxy resin composition. The photocationic polymerization initiator was blended as a 50% concentration propylene carbonate solution. The amount shown above is the solid content.

[Production Example 3] (Preparation of pressure-sensitive adhesive layer)
A release treatment surface of a polyethylene terephthalate film (separator) having a thickness of 38 μm obtained by releasing an organic solvent solution in which a copolymer of butyl acrylate and acrylic acid is mixed with a urethane acrylate oligomer and an isocyanate crosslinking agent. Then, the film was coated with a die coater so that the thickness after drying was 25 μm and dried to form a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive on the separator. The storage elastic modulus of this pressure-sensitive adhesive layer was 1.4 MPa at 23 ° C. Moreover, the adhesive force with respect to glass when this adhesive layer was bonded to the polarizing plate mentioned later and bonded to glass was 5 N / 25mm.

[Production Example 4] (Production of Polarizing Film A)
A polyvinyl alcohol raw film obtained from a certain manufacturer is cut into a size of 25 cm in length and 4 cm in width so that the longitudinal direction (MD) of the roll-like long film becomes a long side, and 7. When immersed in water at 30 ° C. with a 5 g weight, the film had a dimensional change characteristic of 41 mm in 100 seconds and 45 mm in 200 seconds. This polyvinyl alcohol raw film was immersed in pure water at 30 ° C. and then immersed in an aqueous solution containing iodine and potassium iodide at 30 ° C. Thereafter, it was immersed in an aqueous solution containing potassium iodide and boric acid at 56.5 ° C. Subsequently, the film was washed with pure water at 6 ° C. and then dried at 70 ° C. to prepare a polarizing film A in which iodine is adsorbed and oriented. Stretching was mainly performed in the iodine dyeing and boric acid treatment steps so that the total stretch ratio from the raw film was about 5.3 times.

[Production Example 5] (Preparation of polarizing film B)
Another raw film of polyvinyl alcohol obtained from the same manufacturer is cut into a size of 25 cm in length and 4 cm in width so that the longitudinal direction (MD) of the roll-shaped long film is the long side, and at the lower end in the length direction. When a 7.5 g weight was attached and immersed in water at 30 ° C., the film had a dimensional change characteristic of 42 mm in 100 seconds and 46 mm in 200 seconds. Using this polyvinyl alcohol raw film, the same operation as in Production Example 4 was performed to produce a polarizing film B in which iodine was adsorbed and oriented.

[Production Example 6] (Preparation of polarizing film C)
Another polyvinyl alcohol raw film obtained from the same manufacturer is cut into a size of 25 cm in length and 4 cm in width so that the longitudinal direction (MD) of the roll-like long film is the long side, and the lower end in the length direction. When a 7.5 g weight was attached to the test piece and immersed in water at 30 ° C., the film had a dimensional change characteristic of 49 mm in 100 seconds and 57 mm in 200 seconds. Using this polyvinyl alcohol raw film, the same operation as in Production Example 4 was performed, except that the final drying was performed at a temperature of 85 ° C. to produce a polarizing film C in which iodine was adsorbed and oriented.

[Example 1]
(Preparation of polarizing plate)
A transparent protective film (Konica Minolta Opto KC4UX2 manufactured by Konica Minolta Opto Co., Ltd.), which has been subjected to saponification treatment on one surface of the polarizing film A produced in Production Example 4 (the surface on the side far from the liquid crystal cell). ”, 40 μm thick), and the other surface (the liquid crystal cell side surface) is a transparent protective film made of cycloolefin polymer (available from Zeon Corporation, thickness 40 μm, in-plane letter) A polarizing plate was prepared by laminating a retardation R _e = 2.1 nm and a thickness direction retardation R _th = 2.8 nm. For the pasting, the polarizing film and the transparent protective films on both sides were bonded by using the water-based adhesive prepared in Production Example 1 and drying at 80 ° C. for 5 minutes after the pasting. The obtained polarizing plate was then cured at 40 ° C. for 168 hours. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to the surface of the transparent protective film made of the cycloolefin polymer of the polarizing plate to produce a polarizing plate with a pressure-sensitive adhesive layer. The layer structure of the polarizing plate with the pressure-sensitive adhesive layer is as shown in FIG.

(Production and evaluation of IPS mode liquid crystal display device)
Disassemble IPS mode wide 32 type (approx. 71cm x approx. 40cm) liquid crystal display device ("Wooo" manufactured by Hitachi, Ltd. (model number: W32L-H9000)), peel off the polarizing plates above and below the liquid crystal cell Instead of the plate, the two pressure-sensitive adhesive layer-prepared polarizing plates prepared as described above are in a crossed Nicols state on the front side (viewing side) and back side (light incident side) of the liquid crystal cell. The liquid crystal panel was produced by bonding on the layer side. In this case, the absorption axis of the polarizing plate on the front side (viewing side) was arranged so as to be parallel to the alignment direction when no voltage was applied to the liquid crystal molecules in the liquid crystal cell (black display). Using this liquid crystal panel, an IPS mode liquid crystal display device was assembled again.

When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state where no voltage was applied to the liquid crystal cell was visually observed, no local display unevenness was observed. About 22 cm in the vertical direction (long side direction of the screen) from the side (side with a length of about 40 cm) was slightly dark. Therefore, the luminance unevenness in this display state was measured with a luminance / color unevenness analyzer “EyeScale-3W” manufactured by I-System Co., Ltd. The result is shown in FIG. FIG. 6 shows a change in luminance along a straight line on the display screen connecting one end of the short side of the display screen to one end of the short side, and centering around 22 cm from one end where the above-mentioned slight darkness is recognized. Data between 15 cm and 25 cm are shown. 6, the horizontal axis is the distance from the short side end of the display screen as described above (unit: mm), the vertical axis represents luminance at that location (unit: cd / cm ²⁾ is, also, solid lines of luminance The actual measurement data and the broken line are Bezier curves drawn based on the luminance data, and the same applies to FIGS. 7 to 10 below. From this figure, according to the above definition, the luminance change period was calculated to be 2.3 cm, and the luminance change amplitude was calculated to be 0.024 cd / cm ² .

[Example 2]
(Preparation of polarizing plate)
A transparent protective film made of triacetyl cellulose, which is subjected to the same saponification treatment as used in Example 1 on one surface (the surface on the side far from the liquid crystal cell) of the polarizing film A produced in Production Example 4. The transparent protective film which consists of the same cycloolefin polymer as used in Example 1 was bonded to the other surface (surface which becomes a liquid crystal cell side), and the polarizing plate was produced. For the bonding in this example, the photocurable adhesive prepared in Production Example 2 was used, and after the bonding, UV light was integrated with a belt conveyor with an ultraviolet irradiation device (lamp: Fusion D lamp), and the integrated light quantity was 1000 mJ / cm ^2. Was applied to adhere the polarizing film and the transparent protective film on both sides. Then, it was left at room temperature for 1 hour. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to the surface of the transparent protective film made of the cycloolefin polymer of the polarizing plate to produce a polarizing plate with a pressure-sensitive adhesive layer.

(Production and evaluation of IPS mode liquid crystal display device)
Using this polarizing plate with an adhesive layer, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 20 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 7 shows the result. FIG. 7 shows data between 13 cm and 23 cm, centering around 20 cm from one end where the above-mentioned slight darkness was observed. From this figure, the luminance change period was calculated to be 1.7 cm, and the luminance change amplitude was calculated to be 0.027 cd / cm ² .

[Example 3]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
Instead of the transparent protective film made of cycloolefin polymer in Example 1, a transparent protective film made of saponified triacetyl cellulose (“KC4UEW” manufactured by Konica Minolta Opto, thickness 40 μm, in-plane letter A polarizing plate was prepared in the same manner as in Example 1 except that a transparent protective film having a retardation R _e = 0.7 nm and a thickness direction retardation R _th = −0.1 nm was used. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was found, but if you look closely, the short side of the display screen A little unevenness (band that looks bright and dark) about 20cm in the vertical direction (long side of the screen) from Therefore, the luminance unevenness in this display state was measured in the same manner as in Example 1. The result is shown in Fig. 8. Fig. 8 shows the region around 20 cm from one end where the above-described slight unevenness was observed. The data between 15 cm and 25 cm is shown in the center, and from this figure, the period of luminance change was calculated to be 3.8 cm, and the amplitude of luminance change was calculated to be 0.025 cd / cm ² .

[Example 4]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
A polarizing plate was produced in the same manner as in Example 1 except that the polarizing film B produced in Production Example 5 was used instead of the polarizing film A in Example 1, and an IPS mode liquid crystal display device was similarly assembled. . When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed, but the area that seems to be uneven is from the short side of the display screen. It was about 16 cm in the vertical direction (long side direction of the screen). Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 9 shows the result. FIG. 9 shows data between 10 cm and 25 cm centering around 16 cm from one end where the above-mentioned non-uniform state is recognized. From this figure, the luminance change period was calculated to be 4.5 cm.

[Comparative Example 1]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
A polarizing plate was produced in the same manner as in Example 1 except that the polarizing film C produced in Production Example 6 was used instead of the polarizing film A in Example 1, and an IPS mode liquid crystal display device was similarly assembled. . When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, local display unevenness centered around about 15 cm from the short side of the display screen to the vertical direction (long side direction of the screen). Was recognized. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 10 shows the result. FIG. 10 shows data between 10 cm and 20 cm, centering around 15 cm from one end where the local display unevenness is recognized. From this figure, the luminance change period was calculated to be 3 cm, and the luminance change amplitude was calculated to be 0.035 cd / cm ² .

  The layer configurations of the polarizing plates in Examples 1 to 4 and Comparative Example 1 and the results obtained are summarized in Table 1.

(Footnote in Table 1)
TAC4: 40 μm thick triacetyl cellulose film “KC4UX2”,
COP: cycloolefin polymer film with R _e = 2.1 nm, R _th = 2.8 nm,
0-TAC: Triacetyl cellulose film “KC4UEW” with R _e = 0.7 nm and R _th = −0.1 nm.

[Example 5]
(Preparation of polarizing plate)
A transparent protective film (“KC4UX2” manufactured by Konica Minolta Opto Co., Ltd., 40 μm thick) made of saponified triacetyl cellulose is bonded to one surface of the polarizing film A produced in Production Example 4. A polarizing plate was prepared. For pasting, the polarizing film A and the transparent protective film were adhered by drying at 80 ° C. for 5 minutes after the pasting using the aqueous adhesive prepared in Production Example 1. The obtained polarizing plate was then cured at 40 ° C. for 168 hours. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to the polarizing film surface of the polarizing plate to produce a polarizing plate with a pressure-sensitive adhesive layer. The layer structure of the polarizing plate with the pressure-sensitive adhesive layer is as shown in FIG.

(Production and evaluation of IPS mode liquid crystal display device)
In Example 1, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1 except that the polarizing plate with the pressure-sensitive adhesive layer disposed on both surfaces of the liquid crystal cell was changed to the one produced above. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 22 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 11 shows the result. FIG. 11 is a change in luminance along a straight line on the display screen connecting one end of the short side of the display screen to one end of the short side, and centering around 22 cm from the one end where the above-mentioned slight darkness is recognized. Data between 19 cm and 25 cm is shown. In FIG. 11, the horizontal axis represents the distance (unit: mm) from one end of the short side of the display screen, the vertical axis represents the luminance at that location (unit: cd / cm ² ), and the thin line represents the measured luminance data, A thick line is a Bezier curve drawn based on the luminance data, and the same applies to FIGS. From this figure, the luminance change period was calculated to be 2.2 cm, and the luminance change amplitude was calculated to be 0.029 cd / cm ² .

[Example 6]
(Preparation of polarizing plate)
A transparent protective film made of triacetyl cellulose subjected to the same saponification treatment as used in Example 5 was bonded to one surface of the polarizing film A produced in Production Example 4 to produce a polarizing plate. The lamination of this example, using a light curable adhesive prepared in Preparation Example 2, after lamination, the ultraviolet irradiation device with a belt conveyor: at (Lamp Fusion D lamp), ultraviolet integrated light amount 1000 mJ / cm ² The polarizing film A and the transparent protective film were adhered. Then, it was left at room temperature for 1 hour. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to the polarizing film surface of the polarizing plate to produce a polarizing plate with a pressure-sensitive adhesive layer.

(Production and evaluation of IPS mode liquid crystal display device)
Using this polarizing plate with an adhesive layer, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 23 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 12 shows the result. FIG. 12 shows data between 17 cm and 27 cm, centered around 23 cm from one end where the above-mentioned slight darkness was observed. From this figure, the luminance change period was calculated to be 1.9 cm, and the luminance change amplitude was calculated to be 0.026 cd / cm ² .

[Example 7]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
A polarizing plate was produced in the same manner as in Example 5 except that the polarizing film B produced in Production Example 5 was used instead of the polarizing film A in Example 5, and an IPS mode liquid crystal display device was similarly assembled. . When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed, but the area that seems to be uneven is from the short side of the display screen. It was about 20 cm in the vertical direction (long side direction of the screen). Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 13 shows the result. FIG. 13 shows data between 13 cm and 27 cm, centering around 20 cm from one end where the above-mentioned non-uniform state was recognized. From this figure, the luminance change period was calculated to be 10.5 cm.

[Production Example 7] (Preparation of curable resin composition)
The following components were mixed to prepare a curable resin composition.

3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (“Celoxide 2021P” manufactured by Daicel Chemical Industries, Ltd.) 35 parts Bis (3-ethyl-3-oxetanylmethyl) ether (“Aron” manufactured by Toagosei Co., Ltd.) Oxetane OXT-221 ") 15 parts Diacrylate of acetal compound of hydroxypivalaldehyde and trimethylolpropane (" A-DOG "manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts 2-hydroxy-2-methyl-1- Phenylpropan-1-one ("DAROCUR 1173" manufactured by Ciba, photoradical polymerization initiator) 2.5 parts 4,4'-bis (diphenylsulfonio) diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (Daicel Cytec shares The company made "UVACURE 1590") 2.5 parts of a silicone-based leveling agent ( "SH710" manufactured by Dow Corning Toray Co., Ltd.)
0.2 parts.

  In addition, said A-DOG (diacrylate of the acetal compound of a hydroxypivalaldehyde and a trimethylol propane) is a compound which has a structure of following Formula.

Using the above-mentioned curable resin composition on one side of a polyethylene terephthalate (PET) film (“Toyobo Ester Film E5100” manufactured by Toyobo Co., Ltd.) using a coating machine (bar coater manufactured by Daiichi Rika Co., Ltd.) Coating was performed so that the thickness after curing was 4 μm. Next, using a D bulb manufactured by Fusion UV Systems, ultraviolet rays were applied at an integrated light quantity of 1500 mJ / cm ² to cure the coating film. The cured film after peeling the PET film was measured in-plane retardation R _e and the thickness direction retardation R _th. As a result, in-plane retardation R _e is 0.7 nm, the thickness direction retardation R _th was 5.5 nm.

[Example 8]
(Preparation of polarizing plate)
A transparent protective film [KC8UY made by Konica Minolta Opto Co., Ltd.] made of triacetyl cellulose on one side of the polarizing film A produced in Production Example 4 (the side far from the liquid crystal cell) was subjected to saponification treatment. ”, Thickness 80 μm] was bonded to produce a polarizing film with a single-sided protective film. For pasting, the polarizing film and the transparent protective film were bonded by using the water-based adhesive prepared in Production Example 1 and drying at 80 ° C. for 5 minutes after pasting. The obtained polarizing film with a single-sided protective film was then cured at 40 ° C. for 168 hours.

  Separately, the curable resin composition prepared in Production Example 7 was prepared on one side of the same PET film used for the production of the retardation measurement sample in Production Example 7, and the retardation measurement sample was produced in Production Example 7. The coating was carried out under the same conditions as when Next, a coating film of a PET film having a coating film of a curable resin composition on the polarizing film surface of the polarizing film with a single-side protective film produced above using a sticking device (“LPA3301” manufactured by Fuji Plastics Co., Ltd.) The faces were pasted. This bonded product was irradiated with ultraviolet rays from the PET film side under the same conditions as when the sample for retardation measurement was produced in Production Example 7 to cure the coating film. Thereafter, the PET film was peeled off, and a polarizing plate was prepared in which a transparent protective film made of triacetyl cellulose was provided on one side of the polarizing film and a coating type transparent protective layer was provided on the other side. It was 112 micrometers when the thickness of the thickness of this polarizing plate was measured. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to the coating-type transparent protective layer surface to produce a polarizing plate with a pressure-sensitive adhesive layer. The layer structure of the polarizing plate with the pressure-sensitive adhesive layer is as shown in FIG.

(Production and evaluation of IPS mode liquid crystal display device)
In Example 1, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1 except that the polarizing plate with the pressure-sensitive adhesive layer disposed on both surfaces of the liquid crystal cell was changed to the one produced above. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 22 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 14 shows the result. FIG. 14 shows data between 15 cm and 25 cm, centering around 22 cm from one end where the above-mentioned slight darkness was observed. From this figure, the luminance change period was calculated to be 2.5 cm, and the luminance change amplitude was calculated to be 0.025 cd / cm ² .

[Example 9]
(Preparation of polarizing plate)
A transparent protective film made of triacetyl cellulose subjected to the same saponification treatment as used in Example 8 is bonded to one surface of the polarizing film A produced in Production Example 4, and a polarizing film with a single-side protective film Was made. The lamination of this example, using a light curable adhesive prepared in Preparation Example 2, after lamination, the ultraviolet irradiation device with a belt conveyor: the ultraviolet at (lamp Fusion D lamp) with integrated light intensity 1000 mJ / cm ² Irradiated to adhere the polarizing film and the transparent protective film. Then, it was left at room temperature for 1 hour. Next, in the same manner as in Example 8, a coating-type transparent protective layer is formed on the polarizing film surface of the polarizing film with a single-side protective film, and an adhesive layer is further formed on the outer side thereof. Produced.

(Production and evaluation of IPS mode liquid crystal display device)
Using this polarizing plate with an adhesive layer, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 30 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 15 shows the result. FIG. 15 shows data between 25 cm and 35 cm centering around 30 cm from one end where the above-mentioned slight darkness was observed. From this figure, the luminance change period was calculated to be 3.6 cm, and the luminance change amplitude was calculated to be 0.019 cd / cm ² .

[Example 10]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
A polarizing plate was produced in the same manner as in Example 8 except that the polarizing film B produced in Production Example 5 was used instead of the polarizing film A in Example 8, and an IPS mode liquid crystal display device was similarly assembled. . When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed, but the area that seems to be uneven is from the short side of the display screen. It was about 16 cm in the vertical direction (long side direction of the screen). Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 16 shows the result. FIG. 16 shows data between 10 cm and 28 cm centered around 16 cm from one end where the above-mentioned non-uniform state was recognized. From this figure, the luminance change period was calculated to be 9.0 cm.

[Example 11]
(Preparation of polarizing plate)
When a curable resin composition prepared in Production Example 7 is prepared on one side of a polyethylene terephthalate (PET) film (“Toyobo Ester Film E5100” manufactured by Toyobo Co., Ltd.), and a retardation measurement sample is produced in Production Example 7. The coating was carried out under the same conditions. Next, a PET film having a coating film of the curable resin composition on both surfaces of the polarizing film A produced in Production Example 4 is applied to a bonding device (Fuji Plastic) so that the coating film side becomes a bonding surface with the polarizing film. Bonding was performed using “LPA3301” manufactured by Co., Ltd. Under the same conditions as when the sample for retardation measurement was produced in Production Example 7, this bonded product was irradiated with ultraviolet rays from one PET film side, and the coating film provided on both surfaces of the polarizing film was cured. Thereafter, the PET films on both sides were peeled off to produce a polarizing plate having a coating type transparent protective layer provided on both sides of the polarizing film. When the thickness of this polarizing plate was measured, it was 36 μm. Next, the pressure-sensitive adhesive layer shown in Production Example 3 was bonded to one coating-type transparent protective layer surface to produce a polarizing plate with a pressure-sensitive adhesive layer. The layer structure of the polarizing plate with the pressure-sensitive adhesive layer is as shown in FIG.

(Production and evaluation of IPS mode liquid crystal display device)
In Example 1, an IPS mode liquid crystal display device was assembled in the same manner as in Example 1 except that the polarizing plate with the pressure-sensitive adhesive layer disposed on both surfaces of the liquid crystal cell was changed to the one produced above. When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed. Around 15 cm (long side direction) was slightly dark. Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 17 shows the result. FIG. 17 shows data between 10 cm and 20 cm, centering around 15 cm from one end where the above-mentioned slight darkness was observed. From this figure, the luminance change period was calculated to be 3.2 cm, and the luminance change amplitude was calculated to be 0.028 cd / cm ² .

[Example 12]
(Production and evaluation of polarizing plate and IPS mode liquid crystal display device)
A polarizing plate was produced in the same manner as in Example 11 except that the polarizing film B produced in Production Example 5 was used instead of the polarizing film A in Example 11, and an IPS mode liquid crystal display device was similarly assembled. . When the backlight of this liquid crystal display device was turned on and the luminance unevenness in the black display state was visually observed, no local display unevenness was observed, but the area that seems to be uneven is from the short side of the display screen. It was about 16 cm in the vertical direction (long side direction of the screen). Therefore, luminance unevenness in this display state was measured by the same method as in Example 1. FIG. 18 shows the result. FIG. 18 shows data between 10 cm and 28 cm, centering around 16 cm from one end where the above-mentioned non-uniform state was recognized. From this figure, the luminance change period was calculated to be 8.7 cm.

  The layer configurations of the polarizing plates in Examples 5 to 12 and the results obtained are summarized in Table 2 together with the layer configurations of the polarizing plates in Comparative Example 1 described above and the obtained results.

(Footnote in Table 2)
TAC4: 40 μm thick triacetyl cellulose film “KC4UX2”,
TAC8: Triacetyl cellulose film “KC8UY” having a thickness of 80 μm,
COP: cycloolefin polymer film with R _e = 2.1 nm, R _th = 2.8 nm,
Application type: Application type transparent protective layer formed from the curable resin composition of Production Example 7.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 Liquid crystal cell, 11, 12 Cell substrate, 15 Liquid crystal layer, 20 Viewing side polarizing plate, 21 Polarizing film, 25, 26 Transparent protective film, 27, 28 Coating type transparent protective layer, 30 Backlight side polarizing plate, 31 Polarizing film , 35, 36 Transparent protective film, 40, 50 Adhesive layer, 60 Liquid crystal panel, 70 Backlight.

Claims (13)

A liquid crystal cell having two substrates and a liquid crystal layer sandwiched between the two substrates and oriented parallel to the surfaces of the two substrates;
A pair of polarizing plates laminated on both sides of the liquid crystal cell via an adhesive layer;
A backlight, and
Each of the polarizing plates has a polarizing film and a transparent protective layer disposed on the opposite side of the pressure-sensitive adhesive layer for bonding to the liquid crystal cell of the polarizing film,
A liquid crystal display device in which a change in luminance in a black display state satisfies either of the following (1) or (2).
(1) The luminance change period is less than 4 cm, and the luminance change amplitude is 0.03 cd / cm ² or less,
(2) The luminance change cycle is 4 cm or more.   The liquid crystal display device according to claim 1, wherein at least one of the polarizing plates includes a polarizing film and a transparent protective film laminated on both surfaces of the polarizing film via an adhesive layer.   The liquid crystal display device according to claim 2, wherein the transparent protective film disposed on the liquid crystal cell side of the polarizing plate has a thickness direction retardation at a wavelength of 590 nm of -10 to 10 nm.   The liquid crystal display device according to claim 2, wherein the transparent protective film disposed on the liquid crystal cell side of the polarizing plate is made of a cellulose resin or a polyolefin resin.   At least one of the polarizing plates has a polarizing film and a transparent protective film laminated via an adhesive layer on a side far from the liquid crystal cell of the polarizing film, and the side opposite to the transparent protective film The liquid crystal display device according to claim 1, wherein the polarizing film surface is directly laminated on the liquid crystal cell via the pressure-sensitive adhesive layer.   The liquid crystal display device according to claim 2, wherein the adhesive forming the adhesive layer that bonds the polarizing film and the transparent protective film is a water-based adhesive containing a polyvinyl alcohol resin and an epoxy resin. .   The adhesive for forming the adhesive layer that bonds the polarizing film and the transparent protective film is an adhesive made of a curable resin composition containing an epoxy compound that is cured by irradiation with active energy rays or heating. The liquid crystal display device in any one of -5.   The liquid crystal display device according to claim 7, wherein the epoxy compound includes an epoxy compound having at least one epoxy group bonded to an alicyclic ring in a molecule.   At least one of the polarizing plates was formed on a polarizing film, a transparent protective film laminated via an adhesive layer on a side far from the liquid crystal cell of the polarizing film, and the liquid crystal cell side of the polarizing film, The liquid crystal display device according to claim 1, further comprising a coating-type transparent protective layer made of a cured product of a curable resin composition containing an epoxy compound that is cured by irradiation with active energy rays or heating.   At least one of the polarizing plates is a cured product of a curable resin composition containing a polarizing film and an epoxy compound which is formed on the side far from the liquid crystal cell of the polarizing film and which is cured by irradiation with active energy rays or heating. And a cured product of a curable resin composition containing an epoxy compound which is formed on the liquid crystal cell side of the polarizing film and which is cured by irradiation with active energy rays or heating. The liquid crystal display device according to claim 1, further comprising a second coating type transparent protective layer.   The epoxy compound constituting the curable resin composition for forming the coating-type transparent protective layer includes an epoxy compound having at least one epoxy group bonded to an alicyclic ring in the molecule. The liquid crystal display device described.   The coating-type transparent protective layer formed on the liquid crystal cell side of the polarizing film has an in-plane retardation at a wavelength of 590 nm of 10 nm or less and a thickness direction retardation of -10 to 10 nm. A liquid crystal display device according to claim 1.   The said adhesive layer which bonds a liquid crystal cell and a polarizing plate consists of an acrylic adhesive, and the storage elastic modulus in 23 degreeC is 0.15-10 Mpa, and adhesive force with glass is 1-30 N /. It is 25 mm, The liquid crystal display device in any one of Claims 1-12.

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