KR20170042668A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

Disclosure of the Invention Problems to be Solved by the Invention The present invention provides a polarizing plate capable of improving dryness at the time of sticking water, having good productivity, suppressing warping of the liquid crystal panel, and consequently improving display unevenness. The polarizer plate is a polarizer plate provided with a polarizer between a polarizer protective film and a retardation film, and the polarizer protective film and the retardation film are adhered to each other by water, Humidity of 200 to 2000 g / m 2 24 h after 23 hours in the environment, and the dimensional change rate in the range of 23 ° C. 20 to 80% RH is in the range of 0.05 to 0.45% Is in the range of 0.1 to 100 g / m < 2 > 24h after having been left for 24 hours in an environment of 40 DEG C and 90% RH.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polarizing plate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and a liquid crystal display, and more particularly, to a polarizing plate and a liquid crystal display, in which a polarizer is provided between a polarizer protective film and a retardation film, And a display device.

BACKGROUND ART Liquid crystal display devices are in increasing demand in applications such as liquid crystal TVs and liquid crystal displays for personal computers. In general, a liquid crystal display device is composed of a liquid crystal cell in which a transparent electrode, a liquid crystal layer, a color filter and the like are sandwiched between glass plates, and two polarizing plates provided on both sides thereof. Each polarizing plate is a polarizer ) Is sandwiched between two optical films (for example, a polarizer protective film and a retardation film) and adhered with a water-repellent film.

For example, Patent Documents 1 and 2 disclose a polarizing plate using triacetylcellulose (TAC) as a polarizer protective film and a cycloolefin resin as a retardation film.

In recent years, the thickness of the liquid crystal TV screen has been made thinner and larger, and furthermore, the backlight of the LED has been used for the light source, and the thickness of the glass substrate used for the liquid crystal panel has become thinner than 0.7 mm, And the improvement is required.

When the polarizer is placed under high temperature and high humidity, the contraction force acts in the alignment direction in order to alleviate the alignment, and as a result, the liquid crystal panel is bent and the backlight It is supposed that the liquid crystal panel and the backlight unit partially come into contact with each other due to swelling up to the unit side, resulting in display unevenness.

Conventionally, as in Patent Documents 1 and 2, since the thickness of the glass substrate used for the liquid crystal panel is as thick as 0.7 mm or more, the shrinkage of the polarizer is suppressed by the high rigidity of the glass, The panel does not warp, and display irregularity does not become a problem.

Therefore, it has been attempted to improve the warpage of the liquid crystal panel, which occurs when the glass substrate is thinner than 0.7 mm, as an optical film.

For example, when a cycloolefin-based resin is used as a polarizer protective film, there is a problem that the improvement in warpage of the liquid crystal panel is insufficient and the drying property of the water-repellent film for adhering to the polarizer is poor.

In addition, when triacetyl cellulose (TAC) is used as a polarizer protective film, there is a problem that the liquid crystal panel is warped although the dryness of the waterproof film is good.

In addition, when acrylic resin or polyethylene terephthalate (PET) is used as the polarizer protective film, warpage of the liquid crystal panel is improved, but there is a problem that the dryness of the watercolor is poor and productivity is lowered due to low moisture permeability.

Japanese Patent Application Laid-Open No. 2008-107499 Japanese Patent Application Laid-Open No. 2009-198666

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems and circumstances. It is an object of the present invention to provide a liquid crystal display device capable of suppressing warping of a liquid crystal panel with good dryness, good productivity, A polarizing plate and a liquid crystal display device.

In order to solve the above problems, the inventor of the present invention has found that by defining the moisture permeability and dimensional change rate of the polarizer protective film in a specific range and defining the moisture permeability of the retardation film in a specific range, The present invention has been accomplished on the basis of the findings that it is possible to improve the dryness at the time of adhesion of the water-repellent film, the productivity, and the warpage and display irregularity of the liquid-crystal panel.

That is, the above-described problems related to the present invention are solved by the following means.

1. A polarizing plate in which a polarizer is provided between a polarizer protective film and a retardation film and the polarizer protective film and the retardation film are bonded to the polarizer in a water-

Wherein the polarizer protective film has a moisture permeability in a range of 200 to 2000 g / m 2 24 h after being left in an environment of 40 ° C. and 90% RH for 24 hours, and a dimensional change rate in a range of 23 ° C. to 20 to 80% RH Is in the range of 0.05 to 0.45%

Wherein the retardation film has a moisture permeability in a range of 0.1 to 100 g / m < 2 > 24h after being left in an environment of 40 DEG C and 90% RH for 24 hours.

2. The polarizer protective film according to claim 1, wherein the polarizer protective film is a cellulose ester film having a degree of substitution by an aromatic acyl group within a range of 0.4 to 1.5 and a total degree of substitution by an aromatic acyl group and an aliphatic acyl group within a range of 2.6 to 3.0 The polarizer of claim 1.

3. The polarizing plate according to any one of claims 1 to 3, wherein the retardation film is a film containing a cycloolefin-based resin.

4. A liquid crystal display device having a liquid crystal cell sandwiched between glass substrates,

A polarizing plate according to any one of claims 1 to 3, further comprising:

Wherein a thickness of the glass substrate is 0.6 mm or less.

According to the above-mentioned means of the present invention, it is possible to provide a polarizing plate and a liquid crystal display device capable of improving dryness at the time of water-jetting adhesion, having good productivity, suppressing warpage of the liquid crystal panel and consequently improving display unevenness have.

The mechanisms and mechanisms for manifesting the effects of the present invention are not disclosed, but are estimated as follows.

By setting the moisture permeability of the polarizer protective film within the range of 200 to 2000 g / m 2 24 h and the moisture permeability of the retardation film within the range of 0.1 to 100 g / m 2 24 h, when water is adhered to the polarizer, water is released from the polarizer protective film side It becomes easier, the dryness of water is improved, and the productivity is improved. In addition, by setting the dimensional change ratio of the polarizer protective film within the range of 0.05 to 0.45%, it is possible to suppress warpage of the liquid crystal panel even when the glass substrate is thinned, and as a result, display irregularity can be improved.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram schematically showing an example of a dope preparing step, a softening step and a drying step of the solution solution casting method.
2 is a schematic view for explaining an example of the configuration of a liquid crystal display device.

The polarizer of the present invention is a polarizer wherein a polarizer is provided between a polarizer protective film and a retardation film and the polarizer protective film and the retardation film are adhered to each other by water, RH in a range of 200 to 2000 g / m 2 24 h and 23 캜 to 20 to 80% RH in a range of 0.05 to 0.45% after the 24-hour standing, Wherein the retardation film has a moisture permeability in a range of 0.1 to 100 g / m < 2 > 24h after being left in an environment of 40 DEG C and 90% RH for 24 hours. This feature is a technical feature that is common to the claims of the claims 1 to 4.

As an embodiment of the present invention, it is preferable that the polarizer protective film has a degree of substitution by an aromatic acyl group within the range of 0.4 to 1.5 and a total degree of substitution by an aromatic acyl group and an aliphatic acyl group of 2.6 To 3.0. ≪ / RTI > By this, substituent groups such as a hydroxyl group and an acetyl group of cellulose are reduced and an aromatic acyl group is substituted, thereby increasing the molecular hydrophobicity and drastically reducing the dimensional change due to humidity fluctuation. In particular, when the substitution degree by the aromatic acyl group is 1.5 or less, the molecular hydrophobic group is not excessively strong, the saponification property of the film and the suitability of bonding with the polarizer are improved, and the mechanical strength of the film is improved.

From the above, the moisture permeability and dimensional change ratio fall within the above-mentioned range, water is released from the side of the polarizer protective film, the dryness is improved, productivity is improved, and warpage of the liquid crystal panel can be suppressed.

A liquid crystal display device of the present invention is a liquid crystal display device having a liquid crystal cell sandwiched between glass substrates. The liquid crystal display device is provided with the polarizing plate and the thickness of the glass substrate is 0.6 mm or less.

The polarizing plate of the present invention can be suitably used for a liquid crystal display device having a glass substrate of 0.6 mm or less.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, " to " is used to mean that the numerical values described before and after are included as the lower limit value and the upper limit value.

[Polarizer]

The polarizing plate generally comprises a polarizer and an optical film disposed on both sides of the polarizer. The polarizing plate has a function of converting natural light and polarized light into arbitrary polarized light such as linearly polarized light, circularly polarized light, and elliptically polarized light.

<Polarizer>

A polarizer, which is a main component of the polarizer, is a device that allows only light of a polarization plane in a certain direction to pass. A currently known polarizer (also referred to as a polarizer film) is a polyvinyl alcohol polarizer film, Iodine staining and dichroic dye staining.

The polarizer may be a film obtained by forming a polyvinyl alcohol aqueous solution, uniaxially stretching the film, dyeing the film, uniaxially stretching it, and preferably durability treatment with a boron compound.

&Lt; Optical film &

The viewer side polarizing plate has a structure sandwiched between two optical films, and the viewing side polarizing plate has a structure in which an optical film (also referred to as a polarizer protective film) disposed on the viewer side and an optical film (also referred to as a retardation film) And a polarizer is interposed therebetween.

The polarizer on the light source side is constituted by sandwiching a polarizer between an optical film (also referred to as a retardation film) disposed on the liquid crystal cell side and an optical film (also referred to as a polarizer protective film) disposed on the light source side.

A polarizer according to the present invention is a polarizer in which a polarizer is provided between a polarizer protective film and a retardation film, and the polarizer protective film and the retardation film are adhered to each other by water.

(Polarizer protective film)

In the polarizing plate of the present invention, the polarizer protective film preferably has a moisture permeability in the range of 200 to 2000 g / m &lt; 2 &gt; 24h after standing for 24 hours under the environment of 40 DEG C and 90% RH, And the dimensional change ratio in the range is within the range of 0.05 to 0.45%.

The moisture permeability of the polarizer protective film is more preferably in the range of 200 to 1500 g / m &lt; 2 &gt;

The moisture permeability of the polarizer protective film is more preferably in the range of 200 to 1500 g / m &lt; 2 &gt; By setting the water vapor permeability within the range of 200 to 2000 g / m &lt; 2 &gt; .24 h, water-break dryness is good and deterioration of the polarizer due to excess moisture permeation can be suppressed.

That is, the lower limit of the moisture permeability of the polarizer protective film is set to 200 g / m 2 24 h, which is a preferable threshold value for the water droplet formation, and the upper limit value of 2000 g / m 2 24 h is a limit value at which the polarizer does not deteriorate. Within the above range.

The dimensional change ratio of the polarizer protective film is more preferably in the range of 0.05 to 0.30%. When the dimensional change rate is within the range of 0.05 to 0.45%, the film is in a range suitable for film production, and warpage of the liquid crystal panel is suppressed, and display irregularity can be improved.

The lower limit value of the dimensional change rate of 0.05% is the lower limit value set by actually producing and confirming the value of 0.05% or more. Less than 0.05% is considered to be preferable for prediction, but it has not been confirmed, so the present invention has been made. The reason why the upper limit value of the dimensional change rate is set to 0.45% is that the dimensional change rate is within the above range in that it is a limit value that can suppress the warpage of the liquid crystal panel.

<< Measurement of moisture permeability >>

The water vapor permeability in the present invention is a value measured by leaving the film to be measured under the condition of 40 占 폚 and 90% RH for 24 hours based on the calcium chloride-cup method described in JIS Z 0208.

<< Measurement of dimensional change rate >>

The dimensional change rate according to the present invention is a value calculated as follows.

A cross is displayed on two surfaces of the film, and the film is allowed to stand for 24 hours under an environment of 23 ° C and 20% RH, and a distance L ₁ between the two marks is measured with a microscope. Then, after the film allowed to stand for 24 hours under the environment of 23 ℃ and 80% RH, similarly the dimensional change rate (%) by measuring the distance L ₂ between the two displays, the formula was calculated.

Dimensional change ratio (%) = (L ₂ / L ₁ -1) × 100

As means for satisfying the moisture permeability and dimensional change ratio, a cellulose ester resin, a cellulose ether resin (for example, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, Nonethyl cellulose, etc.), and cellulose carbamate resins (e.g., cellulose phenylcarbamate and the like).

Among them, the polarizer protective film according to the present invention includes a cellulose ester resin having a degree of substitution by an aromatic acyl group within a range of 0.4 to 1.5 and a total substitution degree by an aromatic acyl group and an aliphatic acyl group within a range of 2.6 to 3.0 It is preferable to use a cellulose ester film. By lowering the degree of substitution by the aromatic acyl group and the degree of substitution within the above range, the substitutional groups such as the hydroxyl group and the acetyl group of the cellulose are reduced and the aromatic acyl group is substituted, whereby the molecular hydrophobicity is increased and the dimensional change due to the humidity variation is greatly reduced can do. In particular, when the substitution degree by the aromatic acyl group is 1.5 or less, the molecular hydrophobic group is not excessively strong, the saponification property of the film and the suitability of bonding with the polarizer are improved, and the mechanical strength of the film is improved.

From the above, the moisture permeability and dimensional change ratio fall within the above-mentioned range, water is released from the side of the polarizer protective film, the dryness is improved, productivity is improved, and warpage of the liquid crystal panel can be suppressed.

As a means for satisfying the above-mentioned moisture permeability and dimensional change ratio, the thickness of the polarizer protective film is preferably within the range of 10 to 100 mu m, more preferably within the range of 20 to 60 mu m.

<< Cellulose ester resin >>

The cellulose ester resin used for the polarizer protective film according to the present invention is not particularly limited, but the ester group is preferably a linear or branched carboxylic acid ester having about 2 to 22 carbon atoms, and these carboxylic acids may form a ring , Or an ester of an aromatic carboxylic acid. In addition, these carboxylic acids may have a substituent. The cellulose ester is preferably a lower fatty acid ester having 6 or less carbon atoms.

Preferred examples of the cellulose ester resin include cellulose ester mixed fatty acid esters in which a propionate group or a butyrate group is bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate propionate butyrate in addition to cellulose acetate have.

In the present invention, the aliphatic acyl group may be linear, branched or may have a substituent.

<< An aromatic acyl group >>

The aromatic acyl group in the present invention may be directly bonded to the ester bond portion or may be bonded via a linking group, but is preferably bonded directly. The term "linking group" as used herein means an alkylene group, an alkenylene group or an alkynylene group, and the linking group may have a substituent. As the linking group, an alkylene group, an alkenylene group and an alkynylene group preferably having 1 to 10 carbon atoms, more preferably an alkylene group and an alkenylene group having 1 to 6 carbon atoms, most preferably an alkylene group having 1 to 10 carbon atoms Lt; / RTI &gt; to 4 carbon atoms.

The aromatic acyl group may have a substituent. The substituent substituted for the aromatic acyl group and the substituent substituted for the above-mentioned linking group may be, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 20 carbon atoms, More preferably 1 to 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, tert-butyl, n-butyl, (Preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include cyclopentyl, cyclohexyl and the like), an alkenyl group An alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 carbon atoms, such as a vinyl group, an aryl group, a 2-butenyl group and a 3-pentenyl group) To 8, and examples thereof include a propargyl group, a 3-pentynyl group and the like An aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as a phenyl group, a biphenyl group, a naphthyl group, etc.) ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10, and particularly preferably 0 to 6, such as an amino group, a methylamino group, a dimethylamino group, a diethylamino group, An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.) An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16, particularly preferably 6 to 12 carbon atoms, such as a phenyloxy group, a 2-naphthyloxy group, etc.) ), An acyl group (preferably An alkyl group having 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12 carbon atoms, and examples thereof include an acetyl group, a benzoyl group, a formyl group and a pivaloyl group), an alkoxycarbonyl group Preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms, and examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group), an aryloxycarbonyl group The number of carbon atoms is 7 to 20, more preferably 7 to 16, and particularly preferably 7 to 10, and examples thereof include phenyloxycarbonyl group), an acyloxy group (preferably having 2 to 20 carbon atoms , More preferably 2 to 16, particularly preferably 2 to 10, and examples thereof include an acetoxy group and a benzoyloxy group), an acylamino group (preferably having 2 to 20 carbon atoms, more preferably to do (Preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms), preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms, and examples thereof include an acetylamino group and a benzoylamino group), an alkoxycarbonylamino group , Particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, Preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 carbon atom, (For example, methanesulfonylamino group, benzenesulfonylamino group, etc.), sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably (Wherein the number of carbon atoms is preferably from 1 to 20, more preferably from 1 to 20, and still more preferably from 1 to 20, Preferably 1 to 16, particularly preferably 1 to 12, and examples thereof include a carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group and a phenylcarbamoyl group), an alkylthio group (preferably a Preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methylthio group and ethylthio group), an arylthio group (preferably, The number of carbon atoms is 6 to 20, more preferably 6 to 16, and particularly preferably 6 to 12, and examples thereof include phenylthio), a sulfonyl group (preferably having 1 to 20 carbon atoms, More preferably 1 to 16, and particularly preferably 1 (Preferably 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12 carbon atoms, and examples thereof include a methyl group, a tolyl group and the like), a sulfinyl group (Preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as ureido group (e.g., methanesulfonyl group and benzenesulfonyl group) , A methyl ureido group and a phenyl ureido group), a phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as di A fluorine atom, a chlorine atom, a bromine atom, an iodine atom), a cyano group, a sulfo group, a carboxy group, a nitro group, a halogen atom (for example, Rocky mountain group, sulphino group, (Preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom, and specifically, for example, A heterocyclic group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, etc.), a silyl group (preferably a substituted or unsubstituted heterocyclic group), a heterocyclic group , The number of carbon atoms is 3 to 40, more preferably 3 to 30, and particularly preferably 3 to 24, and examples thereof include a trimethylsilyl group, a triphenylsilyl group, etc.). These substituents may be further substituted. When two or more substituents are present, they may be the same or different. In addition, if possible, they may be connected to form a ring.

The aromatic group constituting the aromatic acyl group according to the present invention may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group.

The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 12 carbon atoms, and most preferably 6 to 10 carbon atoms. Specific examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a terphenyl group and the like, and more preferably a phenyl group. As the aromatic hydrocarbon group, a phenyl group, a naphthyl group and a biphenyl group are particularly preferable.

As the aromatic heterocyclic group, it is preferable to include at least one of an oxygen atom, a nitrogen atom and a sulfur atom. Examples of the heterocycle include furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, Wherein the benzene ring is selected from the group consisting of benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, benzene ring, phenylene ring, Benzoxazole, benzothiazole, benzotriazole, tetrazaine, and the like. As the aromatic heterocyclic group, a pyridyl group, a triazinyl group and a quinolyl group are particularly preferable.

Preferred examples of the aromatic acyl group include a phenylacetyl group, a hydrocinnamoyl group, a diphenylacetyl group, a phenoxyacetyl group, a benzyloxyacetyl group, an O-acetylmandryl group, a 3-methoxyphenylacetyl group, Methoxyphenylacetyl group, a phenylacetyl group, a 2,5-dimethoxyphenylacetyl group, a 3,4-dimethoxyphenylacetyl group, a 9-fluorenylmethylacetyl group, a cinnamoyl group, 4-ethylbenzoyl, 4-propylbenzoyl, 4-t-butyl, isobutylthio, tert-butylthio, A 4-pentylbenzoyl group, a 4-heptylbenzoyl group, a 4-octylbenzoyl group, a 4-vinylbenzoyl group, a 4-ethoxybenzoyl group, a 4-butoxy group 4-heptyloxybenzoyl group, 4-pentyloxybenzoyl group, 4-octyloxybenzoyl group, 4-nonyloxybenzoyl group, 4-decyloxybenzoyl group, 4-undecyloxy group Benzo A 4-dodecyloxybenzoyl group, a 4-isopropoxybenzoyl group, a 2,3-dimethoxybenzoyl group, a 2,5-dimethoxybenzoyl group, a 3,4-dimethoxybenzoyl group, a 2,6- Methoxybenzoyl group, 2,4-dimethoxybenzoyl group, 3,5-dimethoxybenzoyl group, 3,4,5-trimethoxybenzoyl group, 2,4,5-trimethoxybenzoyl group, 1-naphtho Biphenylcarbonyl group, 4'-ethyl-4-biphenylcarbonyl group, 4'-octyloxy-4-biphenylcarbonyl group, piperonyloyl group, diphenyl An acetyl group, a triphenylacetyl group, a phenylpropionyl group, a hydrocinnamamoyl group, an? -Methylhydrocinnamoyl group, a 2,2-diphenylpropionyl group, a 3,3-diphenylpropionyl group, Phenylbutyryl group, 3-phenylbutyryl group, 3-phenylbutyryl group, 3-phenylbutyryl group, 4-phenylbutyryl group, Methoxyphenylacetyl group, phenoxyacetyl group, 3-phenoxypropionyl group, 2- (2-methoxyphenyl) propionyl group, a 3- (p-toluyl) propionyl group, a 2-methoxyphenyl group, Methylphenylacetyl group, 4- (4-methoxyphenyl) butyryl group, (2,4-di-t-pentylphenoxy) -acetyl group, (3,4-dimethoxyphenyl) acetyl group, 3,4- (methylenedioxy) phenylacetyl group, 3- (3-tert- Dimethoxyphenyl) propionyl group, 4- (3,4-dimethoxyphenyl) butyryl group, (2,5-dimethoxyphenyl) acetyl group, , A 4,5-trimethoxyphenylacetyl group, a 3- (3,4,5-trimethoxyphenyl) -propionyl group, an acetyl group, a 1-naphthylacetyl group, (2-naphthoxy) acetyl group, 6-methoxy-a-methyl-2-naphthalene acetyl group, 9-fluorene acetyl group , 1-pyrene acetyl group, 1-pyrenebutyl 2-methylcinnamoyl group, 2-methoxycinnamoyl group, 3-methoxycinnamoyl group, 2-methoxycinnamoyl group, 2-methoxycinnamoyl group, , 3-dimethoxycinnamoyl group, 2,4-dimethoxycinnamoyl group, 2,5-dimethoxycinnamoyl group, 3,4-dimethoxycinnamoyl group, 3,5-dimethoxycinnamoyl group, 3 , A 4- (methylenedioxy) cinnamoyl group, a 3,4,5-trimethoxycinnamoyl group, a 2,4,5-trimethoxycinnamoyl group, a 3- Cyclohexyloxy) benzoyl group, 2,3-dimethylbenzoyl group, 2,6-dimethylbenzoyl group, 2,4-dimethylbenzoyl group, 2,5-dimethylbenzoyl group, 3-methoxy- , 3-benzoylbenzoyl group, 4-benzoylbenzoyl group, 2-ethoxy-1-benzoylbenzoyl group, 2-benzoylbenzoyl group, -Naphthoyl group, 9-fluorenecarbonyl group, 1-fluorenecarbonyl group, 4-fluorenecarbonyl group, 9-anthracenecarbonyl , And 1-pyrene group.

Among the above aromatic acyl groups, particularly preferred are benzoyl group, 2,4,6-trimethylbenzoyl group, phenylbenzoyl group, 4-heptylbenzoyl group, 2,4,5-trimethoxybenzoyl group, 5-trimethoxybenzoyl group.

<< Aliphatic acyl groups >>

The aliphatic acyl group in the present invention may be any of linear, branched or cyclic aliphatic acyl groups and may be an aliphatic acyl group containing an unsaturated bond. Preferably an aliphatic acyl group having 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 4 carbon atoms.

Preferable examples of the aliphatic acyl group include an acetyl group, a propionyl group and a butyryl group, and among them, an acetyl group is preferable. By using an aliphatic acyl group as an acetyl group, a film having an appropriate glass transition point (Tg), an elastic modulus and the like can be obtained. By having an aliphatic acyl group having a small carbon number such as an acetyl group, appropriate strength can be obtained as a film without lowering the Tg and the modulus of elasticity.

The part not substituted with an acyl group usually exists as a hydroxy group. These can be synthesized by a known method.

The substitution degree of the acetyl group or the substitution degree of the other acyl group can be obtained by the method defined in ASTM-D817-96.

The weight average molecular weight (Mw) of the cellulose ester resin used for the polarizer protective film according to the present invention is preferably 75000 or more, more preferably 75000 to 300000, further preferably 100000 to 240000 , And particularly preferably from 160000 to 240000. When the weight average molecular weight (Mw) of the cellulose ester resin is 75000 or more, the effect of improving the magnetic film forming property and adhesion of the cellulose ester resin layer itself is exhibited, which is preferable. In the present invention, two or more kinds of cellulose ester resins may be mixed and used.

The average molecular weight (Mn, Mw) of the cellulose ester resin can be measured by gel permeation chromatography under the following measurement conditions.

Solvent: methylene chloride

Column: Shodex K806, K805, K803G (connected to three of Shawda Denko Co., Ltd.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: Standard curve of polystyrene STK standard A calibration curve of 13 samples with polystyrene (manufactured by TOSO CORPORATION) Mw = 500 to 2800000 was used. The 13 samples are preferably used at substantially equal intervals.

(Retardation film)

The retardation film has a moisture permeability in a range of 0.1 to 100 g / m 2 24 h after being left in an environment of 40 ° C and 90% RH for 24 hours. More preferably, it is in the range of 1.0 to 100 g / m &lt; 2 &gt;

When the moisture permeability of the retardation film is 0.1 g / m &lt; 2 &gt;. 24 h, which is the lower limit value, the saponification property of the film and the bonding suitability with the polarizer are good and the productivity of the polarizing plate is improved. When the upper limit value is 100 g / , The moisture permeability was within the above range.

The lower limit value of the moisture permeability of 0.1 g / m &lt; 2 &gt; .sub.24 h is the lower limit value which is established and confirmed to be 0.1 g / m &lt; 2 &gt; It is thought that 0.1 g / m &lt; 2 &gt; The preferable lower limit value of 1.0 g / m &lt; 2 &gt; .24 h is 1.0 g / m &lt; 2 &gt; Particularly preferably 3.0 to 100 g / m 2 24 h.

As means for satisfying the moisture permeability, it is preferable to use an acrylic resin or a cycloolefin resin as the film member used for the retardation film. In particular, the retardation film according to the present invention is preferably a film containing a cycloolefin-based resin. Among the cycloolefin-based resins, it is particularly preferable to use a norbornene-based resin.

As a means for satisfying the moisture permeability, the thickness of the retardation film is preferably in the range of 10 to 100 mu m, more preferably in the range of 20 to 60 mu m.

<< Acrylic resin >>

The acrylic resin used in the retardation film according to the present invention also includes methacrylic resin. The resin is not particularly limited, but it preferably contains 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith.

As the acrylic resin and the methacrylic resin, a copolymer of a (meth) acrylic monomer or a copolymer of a (meth) acrylic monomer and a copolymerizable monomer can be used. Examples of (meth) acrylic monomers include (meth) acrylic acid; (Meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, t- (Meth) acrylic acid C1-10 alkyl such as ethylhexyl; (Meth) acrylate such as phenyl (meth) acrylate; Hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; Glycidyl (meth) acrylate; N, N-dialkylaminoalkyl (meth) acrylate; (Meth) acrylonitrile; (Meth) acrylate having an alicyclic hydrocarbon group such as tricyclodecane, and the like. Examples of the copolymerizable monomers include styrene-based monomers, vinyl ester-based monomers, maleic anhydride, maleic acid, and fumaric acid. These monomers may be used alone or in combination of two or more.

Examples of the (meth) acrylic resin include poly (meth) acrylates such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymers, methyl methacrylate- (meth) Acrylic acid ester-methacrylic acid copolymer, (meth) acrylic acid ester-styrene copolymer (MS resin, etc.), and the like. Preferred examples of the (meth) acrylic resin include poly (meth) acrylate C1-6 alkyl such as methyl (meth) acrylate, particularly methyl methacrylate as a main component (50 to 100 mass%, preferably 70 to 100 mass% Methyl methacrylate-based resin.

Of these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, and 2-ethylhexyl acrylate are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer , Methyl acrylate or n-butyl acrylate are particularly preferably used.

The acrylic resin used in the retardation film according to the present invention has a weight average molecular weight (Mw) of at least 80000, in particular, from the viewpoint of improving the brittleness as a retardation film. When the weight-average molecular weight (Mw) of the acrylic resin is less than 80,000, improvement in sufficient brittleness is not obtained. The weight average molecular weight (Mw) of the acrylic resin is more preferably in a range of from 80000 to 1000000, particularly preferably in a range of from 100000 to 600000, and most preferably in a range of from 150000 to 400000. The upper limit value of the weight average molecular weight (Mw) of the acrylic resin is not particularly limited, but is preferably in the range of 1000000 or less from the viewpoint of production.

Commercially available acrylic resins for use in the retardation film according to the present invention may also be used. (Manufactured by Asahi Kasei Chemicals Corporation), Dianal BR52, BR80, BR83, BR85 and BR88 (manufactured by Mitsubishi Rayon Co., Ltd.) and KT75 (manufactured by Denki Kagaku Kogyo Co., Ltd.) And the like. Two or more acrylic resins may be used in combination.

<< Cycloolefin Resin >>

The cycloolefin resin used in the retardation film according to the present invention comprises a polymer resin containing an alicyclic structure.

A preferred cycloolefin-based resin is a resin obtained by polymerizing or copolymerizing a cyclic olefin. As the cyclic olefin, norbornene, dicyclopentadiene, tetracyclododecene, ethyl tetracyclododecene, ethylidene tetracyclododecene, tetracyclo [7.4.0.1 ^10,13 .0 ^2,7] deca-tree -2 , 4,6,11-tetraene and the like, and derivatives thereof; Cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a- -4,7-methano-1H-indene, cycloheptene, cyclopentadiene, cyclohexadiene, and derivatives thereof. These cyclic olefins may have a polar group as a substituent. Examples of the polar group include a hydroxyl group, a carboxy group, an alkoxyl group, an epoxy group, a glycidyl group, an oxycarbonyl group, a carbonyl group, an amino group, an ester group and a carboxylic acid anhydride group. Particularly, an ester group, a carboxyl group or a carboxylic acid anhydride group is suitable .

The preferred cycloolefin-based resin may be a copolymer obtained by addition-copolymerizing a monomer other than the cyclic olefin. Examples of the addition-copolymerizable monomer include ethylene and? -Olefins such as ethylene, propylene, 1-butene and 1-pentene; Dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene and 1,7-octadiene.

The cyclic olefin is obtained by an addition polymerization reaction or a metathesis ring-opening polymerization reaction. The polymerization is carried out in the presence of a catalyst.

As the catalyst for addition polymerization, for example, a polymerization catalyst containing a vanadium compound and an organoaluminum compound can be given.

A polymerization catalyst comprising a halide, nitrate or acetylacetone compound of a metal such as ruthenium, rhodium, palladium, osmium, iridium or platinum and a reducing agent as a catalyst for ring opening polymerization; Or a halide or acetyl acetone compound of a metal such as titanium, vanadium, zirconium, tungsten or molybdenum, and a polymerization catalyst containing an organoaluminum compound.

Polymerization temperature, pressure and the like are not particularly limited, but are usually polymerized at a polymerization temperature in the range of -50 to 100 占 폚 and a polymerization pressure in the range of 0 to 490 N / cm2.

The cycloolefin-based resin used in the retardation film of the present invention is preferably one obtained by polymerizing or copolymerizing a cyclic olefin and then performing a hydrogenation reaction to change the unsaturated bond in the molecule to a saturated bond.

The hydrogenation reaction is carried out by blowing hydrogen in the presence of a known hydrogenation catalyst. Examples of the hydrogenation catalyst include cobalt acetate / triethyl aluminum, nickel acetylacetonato / triisobutyl aluminum, titanocene dichloride / n-butyl lithium, zirconocene dichloride / sec-butyllithium, tetrabutoxy titanate / dimethylmagnesium A homogeneous catalyst comprising a combination of a transition metal compound / alkyl metal compound; Heterogeneous metal catalysts such as nickel, palladium, and platinum; Heterogeneous solid support catalysts prepared by supporting a metal catalyst such as nickel / silica, nickel / diatomaceous earth, nickel / alumina, palladium / carbon, palladium / silica, palladium / diatomaceous earth or palladium / alumina on a carrier.

Alternatively, as the cycloolefin resin, the following norbornene resin may be mentioned. The norbornene resin preferably has a norbornene skeleton as a repeating unit, and specific examples thereof include those described in JP-A-62-252406, JP-A-62-252407, JP- JP-A-133413, JP-A-63-145324, JP-A-63-264626, JP-A-1-240517, JP-A-57-8815, JP- JP-A-39403, JP-A-5-43663, JP-A-5-43834, JP-A-5-70655, JP-A-5-279554, JP- Those described in JP-A-206985, JP-A-7-62028, JP-A-8-176411, and JP-A-9-241484 can be preferably used, but the present invention is not limited thereto. These may be used alone, or two or more kinds may be used in combination.

In the present invention, among the above norbornene resins, those having a repeating unit represented by one of the following structural formulas (I) to (IV) are preferable.

In the structural formulas (I) to (IV), A, B, C and D each independently represent a hydrogen atom or a monovalent organic group.

Among the above norbornene resins, a hydrogenated (meth) acrylate obtained by hydrogenating a polymer obtained by metathesis polymerization of at least one compound represented by the following structural formula (V) or (VI) and an unsaturated cyclic compound copolymerizable therewith Polymers are also preferred.

In the structural formulas, A, B, C and D each independently represent a hydrogen atom or a monovalent organic group. Herein, A, B, C and D are not particularly limited, but an organic group may be connected via a hydrogen atom, a halogen atom, a monovalent organic group or at least a divalent linking group, and they may be the same or different . In addition, A or B and C or D may form a monocyclic or polycyclic structure. The at least bivalent connecting group includes a hetero atom represented by an oxygen atom, a sulfur atom and a nitrogen atom, and examples thereof include an ether, an ester, a carbonyl, a urethane, an amide and a thioether. It is not. Further, through the linking group, the organic group may be further substituted.

Examples of other monomers copolymerizable with the norbornene monomers include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, ,? -Olefins having 2 to 20 carbon atoms such as 1-hexadecene, 1-octadecene and 1-eicosene, and derivatives thereof; Cycloolefins such as cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene, and derivatives thereof; Nonconjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene and 1,7-octadiene; Etc. are used. Of these,? -Olefins, particularly ethylene, are preferred.

These monomers copolymerizable with the norbornene monomers may be used alone or in combination of two or more. When the norbornene monomer and the other monomer copolymerizable with the norbornene monomer are addition-copolymerized, the ratio of the structural units derived from the norbornene monomer and the other monomers copolymerizable with the structural unit derived from the norbornene monomer in the addition copolymer is usually 30: 70 to 99: 1, preferably 50: 50 to 97: 3, more preferably 70: 30 to 95: 5.

When the unsaturated bonds remaining in the molecular chain of the synthesized polymer are saturated by the hydrogenation reaction, the hydrogenation ratio is preferably 90% or more, more preferably 95% or more, particularly preferably 90% or more, Is 99% or more.

Examples of the cycloolefin-based resin used in the present invention include thermoplastic saturated norbornene-based resins described in paragraphs [0014] to [0019] of JP-A-5-2108, JP-A-2001-277430 A thermoplastic norbornene polymer described in paragraphs [0015] to [0031], a thermoplastic norbornene resin described in paragraphs [0008] to [0045] of JP-A No. 2003-14901, JP 2003-139950 A norbornene resin composition described in paragraphs [0014] to [0028], a norbornene resin described in paragraphs [0029] to [0037] of Japanese Patent Application Laid-Open No. 2003-161832, A norbornene resin described in paragraphs [0027] to [0036] of JP-A No. 195268, a polymer resin containing an alicyclic structure described in paragraphs [0009] to [0023] of JP-A No. 2003-211589, Patent Publication No. 2003-211588 may be mentioned the paragraphs [0008] to a norbornene polymer resin or a vinyl alicyclic hydrocarbon polymer resin described in [0024] the like.

Specific examples thereof include Zeonex, ZEONOR40, ZEONOR40 manufactured by Nippon Zeon Co., Ltd., Atton manufactured by JSR Corp., APEL (APL8008T, APL6509T, APL6013T, APL5014DP, APL6015T) manufactured by Mitsui Chemicals, Lt; / RTI &gt;

The molecular weight of the cycloolefin-based resin used in the present invention is appropriately selected depending on the purpose of use, but is not limited to polyisoprene or polyisoprene measured by gel permeation chromatography of a cyclohexane solution (toluene solution when the polymer resin is not dissolved) When the weight average molecular weight in terms of polystyrene is in the range of usually 5000 to 500000, preferably 8000 to 200000, and more preferably 10000 to 100000, the mechanical strength and moldability of the molded article are highly balanced and suitable.

The polarizer protective film and the retardation film according to the present invention may be composed of resins or additives other than the above-mentioned cellulose ester resin, acrylic resin and cycloolefin-based resin, so long as the function as the optical film is not impaired. When a resin other than a cellulose ester resin, an acrylic resin and a cycloolefin resin is contained, the added resin may be in a commercial state or may be mixed without being dissolved.

When resins or additives other than cellulose ester resin, acrylic resin and cycloolefin resin are used, it is preferable to adjust the addition amount within a range that does not impair the functions of the polarizer protective film and the retardation film of the present invention.

(additive)

<< Plasticizer >>

In the polarizer protective film and the retardation film according to the present invention, a plasticizer may be used in combination to improve the fluidity and flexibility of the composition. Examples of the plasticizer include a phthalate ester, a fatty acid ester, a trimellitate ester, a phosphate ester, a polyester, and an epoxy.

Of these, polyester-based and phthalate ester-based plasticizers are preferably used. The polyester-based plasticizer is superior to the phthalate ester-based plasticizer such as dioctyl phthalate in its non-planarity and extrudability, but its plasticizing effect and compatibility are somewhat poor.

Therefore, these plasticizers can be selected or used in combination according to the application, so that they can be applied to a wide variety of applications.

The polyester plasticizer is a reaction product of a monovalent to tetravalent carboxylic acid and a monovalent to hexavalent alcohol, but mainly a product obtained by reacting a divalent carboxylic acid with a glycol is used. Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, and sebacic acid.

Particularly, when adipic acid, phthalic acid or the like is used, excellent plasticizability is obtained. Examples of glycols include glycols such as ethylene, propylene, 1,3-butylene, 1,4-butylene, 1,6-hexamethylene, neopentylene, diethylene, triethylene and dipropylene. These dicarboxylic acids and glycols may be used singly or in combination.

The ester plasticizer may be in the form of an ester, an oligoester, or a polyester. The molecular weight is preferably in the range of 100 to 10000, but preferably 600 to 3000 is effective for plasticizing.

The viscosity of the plasticizer is related to the molecular structure and the molecular weight, but in the case of the adipic acid plasticizer, the range of 200 to 5000 MPa ((25 캜) is preferable from the viewpoint of compatibility and plasticization efficiency. In addition, some polyester plasticizers may be used in combination.

The plasticizer is preferably added in an amount of 0.5 to 30 parts by mass based on 100 parts by mass of the polarizer protective film or the retardation film of the present invention. When the addition amount of the plasticizer is 30 parts by mass or less, the surface is not sticky, which is practically preferable.

<< UV absorber >>

The polarizer protective film or retardation film according to the present invention preferably contains an ultraviolet absorber. Examples of the ultraviolet absorber include benzotriazole-based, 2-hydroxybenzophenone-based or salicylic acid phenyl ester-based ones . For example, there can be mentioned 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5- , Triazole compounds such as 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- Phenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

Among ultraviolet absorbers, an ultraviolet absorber having a molecular weight of 400 or more has a high boiling point and is difficult to volatilize and does not easily scatter even at high temperature molding. Therefore, the addition of a relatively small amount can effectively improve weather resistance.

Examples of the ultraviolet absorber having a molecular weight of not less than 400 include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- (2,2,6,6-tetramethyl-4-piperidyl) benzophenone-based compound such as bis (2,2,6,6-tetramethyl- Sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and furthermore 2- (3,5-di-t-butyl- 1- [2- [3- (3,5-di-t-butoxycarbonyl) -2-n-butylmalonic acid bis (1,2,2,6,6- Propyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6- Tetramethylpiperidine, and the like. These compounds may be used alone or in combination of two or more thereof. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

<< Other additives >>

In addition, various antioxidants may be added to the polarizer protective film or retardation film of the present invention in order to improve the thermal decomposition property and heat coloring property at the time of molding. It is also possible to add an antistatic agent to impart antistatic properties to the polarizer protective film or the retardation film.

A flame retardant acrylic resin composition in which a phosphorus flame retardant is blended may be used for the polarizer protective film or retardation film according to the present invention.

Examples of the phosphorus-based flame retardant used herein include triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, arylphosphonic acid compound, arylphosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphate ester, halogen-containing condensed phosphate ester , Halogen-containing condensed phosphonic acid esters, halogen-containing phosphorous acid esters, and the like.

Specific examples thereof include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl) Tris (tribromoneopentyl) phosphate, and the like.

&Lt; Film forming method of optical film &

An example of a film forming method of an optical film according to the present invention using a cellulose ester resin or an acrylic resin is described, but the present invention is not limited thereto. As the film forming method of the optical film, a manufacturing method such as an inflation method, a T-die method, a calendering method, a cutting method, a soft method, an emulsion method and a hot press method can be used. From the viewpoints of suppression of optical defects of the solution, and the like.

(Organic solvent)

The organic solvent useful for forming the dope when prepared by the solution casting method can be used without limitation as long as it dissolves the cellulose ester resin, the acrylic resin and other additives at the same time.

Examples of the chlorinated organic solvent include methylene chloride and examples of the non-chlorinated organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, , Ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3 , 3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro -1-propanol, nitroethane and the like, and methylene chloride, methyl acetate, ethyl acetate and acetone are preferably used.

The dope preferably contains, in addition to the organic solvent, a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40 mass%. When the proportion of alcohol in the dope is high, the web is gelled and the separation from the metal support is facilitated. When the ratio of the alcohol is small, the non-chlorine organic solvent system also promotes dissolution of the cellulose ester resin or acrylic resin.

Particularly, a dope composition in which at least a total of 15 to 45 mass% of a cellulose ester resin or an acrylic resin and other compounds are dissolved in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms Do.

Examples of the straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Ethanol is preferable because the stability and boiling point of these internal dope are relatively low and the drying property is also good.

Hereinafter, a preferable film-forming method of the optical film according to the present invention will be described.

(1) Dissolution Process

A step of dissolving a cellulose ester resin or an acrylic resin and optionally other additives in an organic solvent mainly composed of a good solvent for a cellulose ester resin or an acrylic resin while stirring to form a dope, A step of mixing a resin or an acrylic resin solution with other additive solutions as occasion demands to form a dope as a main dissolving solution.

The dissolution of the cellulose ester resin or the acrylic resin may be carried out at a normal pressure, a method in which the solvent is used at a boiling point or lower, a method in which the solvent is pressurized at a boiling point or more of the main solvent, JP-A 9-95544, Various methods such as a method of carrying out by a cooling dissolution method as disclosed in JP-A-95557 or a method of JP-A-9-95538 and a method of carrying out at high pressure as disclosed in JP-A-11-21379 However, it is particularly preferable to perform the method by pressurizing at a boiling point or more of the main solvent.

The amount of the cellulose ester resin or acrylic resin in the dope is preferably in the range of 15 to 45 mass% in total. Additives are added to the dope during or after dissolution, dissolved and dispersed, filtered with a filter, defoamed, and sent to the next process with a liquid-feeding pump.

It is preferable to use a filtration material having a collection particle diameter within a range of 0.5 to 5 mu m and a filtration time within a range of 10 to 25 sec / 100 ml for a filtration time.

In this method, the aggregate remaining at the time of dispersing the particles or the aggregates generated at the time of adding the main dope is used as a filter medium having a collection particle diameter within a range of 0.5 to 5 mu m and a filtration time within a range of 10 to 25 sec / Can be removed. In the main dope, since the concentration of the particles is sufficiently thin compared with the addition liquid, the aggregates stick to each other at the time of filtration, and the filtration pressure does not increase suddenly.

Fig. 1 is a diagram schematically showing an example of a dope preparing step, a softening step and a drying step of a solution casting film-forming method preferable in the present invention.

If necessary, large aggregate is removed from the charging kiln 41 by the filter 44, and is sent to the stock kiln 42. Thereafter, various additive liquids are added from the stock kiln 42 to the main dope melting furnace 1.

Thereafter, the main dope is filtered with the main filter 3, and the ultraviolet absorbent added liquid is added inline from the conduit 16 to the main filter.

In many cases, the main dope may contain about 10 to 50 mass% of recovered scrap.

The recovered scrap is obtained by finely crushing an optical film, and an optical film fabric produced by cutting out both side portions of the film, which is generated when filming an optical film, or speckled out is used.

It is also preferable to previously knead the cellulose ester resin or the acrylic resin and, if necessary, other compounds to pelletize them.

(2) Flexible process

An endless metal belt 31 for feeding the dope to the pressure die 30 through a feed pump (for example, a pressurized metering gear pump) and infinitely feeding it, for example, a stainless steel belt or a rotating metal drum In a flexible position on a metal support of a press die slit.

It is preferable to use a press die which can adjust the slit shape of the nipping portion of the die and make the film thickness uniform. The press die includes a coat hanger die and a T die, all of which are preferably used. The surface of the metal support is mirror-finished. Two or more pressure dies may be provided on the metal support in order to increase the film forming speed and the doping amount may be divided into two or more layers. Alternatively, it is also preferable to obtain a laminated structure film by a covalent bonding method in which a plurality of doughs are simultaneously flexible.

(3) Solvent Evaporation Process

The web (flexible dope on a flexible support and dope formed on the support) is heated on a flexible support to evaporate the solvent.

In order to evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back surface of the support by liquid, and a method of transferring heat from the front and rear sides by radiant heat. Do. Also, a method of combining them is also preferably used. It is preferable to dry the web on the supporter after the softening in an atmosphere in the range of 40 to 100 DEG C on the supporter. In order to maintain the temperature within the range of 40 to 100 DEG C, it is preferable to warm the warm air at this temperature to the top surface of the web or to heat it by means of infrared rays or the like.

From the standpoint of surface quality, moisture permeability and releasability, it is preferable to peel the web from the support within 30 to 120 seconds.

(4) Peeling process

And peeling the web from which the solvent has evaporated on the metal support at the peeling position. The peeled web is sent to the next process.

The temperature at the peeling position on the metal support is preferably in the range of 10 to 40 占 폚, more preferably in the range of 11 to 30 占 폚.

The amount of the residual solvent at the time of peeling the web on the metal support at the time of peeling is desirably peeled in the range of 50 to 120 mass% depending on the strength of the drying condition, the length of the metal support, etc. However, When the web is peeled off, the flatness is deteriorated when peeling off and the web is liable to be scraped off due to peeling tension. Therefore, the amount of the residual solvent at the time of peeling is determined by a balance between economic speed and quality.

The amount of residual solvent in the web is defined by the following equation.

Residual solvent amount (%) = (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) 占 100

The heat treatment at the time of measuring the residual solvent amount means that the heat treatment is performed at 115 캜 for one hour.

The peeling tension when peeling the film from the metal support is usually in the range of 196 to 245 N / m, but peeling is preferably carried out with a tensile force of 190 N / m or less when wrinkles tend to occur at peeling, Preferably in the range of the lowest tensile strength to 166.6 N / m, then the lowest tension to 137.2 N / m, but particularly preferably the lowest tensile strength to 100 N / m.

In the present invention, the temperature at the peeling position on the metal support is preferably in the range of -50 to 40 占 폚, more preferably in the range of 10 to 40 占 폚, and most preferably in the range of 15 to 30 占 폚 desirable.

(5) Drying and drawing process

After peeling, a drying device 35 for conveying the web alternately in a plurality of rolls arranged in the drying apparatus and conveying the web, and / or a tenter stretching device 34 for clipping and conveying both ends of the web with clips, Dry.

The drying means generally blows hot air on both sides of the web, but there is also a means for heating the microwave in place of the wind. Too rapid drying tends to impair the planarity of the finished film. Drying at a high temperature is preferably performed at a residual solvent of about 8 mass% or less. And the drying is carried out within a range of approximately 40 to 250 ° C. Particularly, it is preferable to dry in the range of 40 to 160 ° C.

In the case of using the tenter stretching device, it is preferable to use a device capable of independently controlling the gripping length of the film (the distance from the start of gripping to the end of gripping) by the left and right gripping means of the tenter. Further, in the tentering process, it is also desirable to make a compartment having a temperature that is intentionally different in order to improve planarity.

It is also preferable to form a neutral zone so that the respective compartments do not cause interference between different temperature zones.

Further, the stretching operation may be carried out by dividing into a plurality of steps or biaxial stretching in the machine direction and the width direction. In the case of biaxial stretching, simultaneous biaxial stretching may be performed, or may be performed stepwise.

In this case, the stepwise means that, for example, the stretching in which the stretching directions are different can be sequentially performed, the stretching in the same direction can be divided into multiple steps, and the stretching in different directions can be added to any stage. That is, for example, the following stretching step is also possible.

- Stretching in the flexible direction - Stretching in the width direction - Stretching in the flexible direction - Stretching in the flexible direction

- stretching in the width direction - stretching in the width direction - stretching in the softening direction - stretching in the softening direction

Further, simultaneous biaxial stretching may include stretching in one direction and shrinking the other by relaxing the tension. The preferred stretching magnification of the simultaneous biaxial stretching can be in the range of 1.01 to 1.5 times in both the width direction and the longitudinal direction.

The amount of the residual solvent in the web in the case of tentering is preferably in the range of 20 to 100 mass% at the start of the tenter, and the drying is carried out while the tenter is applied until the amount of residual solvent in the web becomes 10 mass% And more preferably not more than 5% by mass.

The drying temperature in the case of performing the tenter is preferably in the range of 30 to 160 占 폚, more preferably in the range of 50 to 150 占 폚, and most preferably in the range of 70 to 140 占 폚.

In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of increasing the uniformity of the film, and the temperature distribution in the width direction in the tenter process is preferably within ± 5 ° C, More preferably within ± 1 ° C.

(6) Coiling process

When the amount of the residual solvent in the web becomes 2% by mass or less and then the optical film is taken up by the take-up machine 37, and the amount of residual solvent is 0.4% by mass or less, a film having good dimensional stability can be obtained. Particularly preferably 0.00 to 0.10% by mass.

As the winding method, a generally used one may be used, such as a constant torque method, a constant tension method, a taper tension method, and a program tension control method with a constant internal stress, and they may be used separately.

The optical film according to the present invention is preferably a long film, specifically about 100 to 5000 m, and is usually provided in a roll form. Further, the width of the film is preferably in the range of 1.3 to 4 m, more preferably in the range of 1.4 to 2 m.

An example of a film-forming method of an optical film according to the present invention using a cycloolefin-based resin will be described.

As a film forming method of an optical film using a cycloolefin resin, any known method may be employed, and the film can be formed by, for example, a solution casting method, a melt molding method or the like.

In order to form a film by the solution casting method, first, a high-boiling solvent such as toluene, xylene, ethylbenzene, chlorobenzene, triethylbenzene, diethylbenzene or isopropylbenzene, or a solvent such as cyclohexane, , Tetrahydrofuran, hexane, octane and the like, preferably 5 to 60 mass% of the cycloolefin-based resin is dissolved to obtain a resin solution.

The obtained resin solution is poured on a heat-resistant film such as polyethylene terephthalate, a steel belt, a metal foil or the like using a bar coater, a doctor knife, a Meyer bar, a roll,

In order to form a film by a melt molding method, a method using a T-die or a melt extrusion method such as an inflation method, a calendering method, a hot pressing method, an injection molding method, or the like is used.

The thickness of the optical film using the cycloolefin-based resin is preferably in the range of 5 to 100 mu m, more preferably in the range of 10 to 80 mu m. If the thickness of the film is 5 占 퐉 or more, the strength is improved, and if the endurance test of the polarizing plate is performed, the curl becomes small. When the thickness is 100 m or less, the transparency is improved and the water vapor permeability is increased and the dryness of the water layer is improved.

[Production method of polarizing plate]

The polarizing plate according to the present invention can be manufactured by a general method. For example, an alkali saponification treatment is performed on the polarizer side of the polarizer protective film according to the present invention, and the film is bonded to at least one side of the polarizer produced by immersion stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution . Further, the retardation film of the present invention similarly subjected to the alkali saponification treatment is bonded to the other surface of the polarizer using a water-shed. It is preferable that the optical film containing an acrylic resin and a cycloolefin resin be subjected to a corona discharge treatment before the saponification treatment.

Corona discharge treatment refers to a treatment to be performed by applying a high voltage of 1 kV or higher between electrodes under atmospheric pressure and discharging. By the corona treatment, an oxygen-containing polar group (a hydroxyl group, a carbonyl group, a carboxylic acid group or the like) is generated on the surface of the resin of the retardation film, and the surface is hydrophilized.

The corona discharge treatment can be performed using a device commercially available from Gaso Denki Co., Ltd. or Toyo Denki Co., The strength of the corona discharge treatment depends on the distance between the electrodes, the output per unit area, and the frequency of the generator. One electrode (A electrode) of the corona discharge treatment apparatus can be commercially available, but the material can be selected from aluminum, stainless steel, and the like. And the other is an electrode (B electrode) for wrapping the plastic film, and is a roll electrode provided at a certain distance from the A electrode so that the corona discharge treatment is performed stably and uniformly. Those which are usually available on the market can also be used. Rolls made of aluminum, stainless steel, or their metal, such as ceramic, silicone, EPT rubber, Haiphalon rubber or the like, are preferably used.

The polarizer, which is a main component of the polarizer, is a device that allows only light of a polarization plane in a certain direction to pass. A typical polarizer film currently known is a polyvinyl alcohol polarizer film. This is a film obtained by dyeing a polyvinyl alcohol film with iodine, And dye-colored dyes.

As the polarizer, a film obtained by forming a polyvinyl alcohol aqueous solution as described above, uniaxially stretching it, dyeing it, dyeing it, uniaxially stretching it, and preferably durability treatment with a boron compound is used.

[Liquid crystal display device]

A liquid crystal display device according to the present invention is a liquid crystal display device having a liquid crystal cell sandwiched between glass substrates and has the above-described polarizing plate according to the present invention, wherein the glass substrate has a thickness of 0.6 mm or less .

&Lt; Configuration of Liquid Crystal Display Device &

As an example of the structure of the conventional liquid crystal display device, in the direct type, as shown in Fig. 2, light from the light source side (light source 1a / diffuser plate (lower diffusion sheet) 3a / condenser sheet 4a (Polarizer 10a / optical film (phase difference film or the like) 9a or 9b / substrate 8a / liquid crystal cell 7a / optical film (polarizer 10a) / liquid crystal panel 12a (A protective film, etc.) 11a and 11b), and is mainly used in a large-sized liquid crystal display device such as a television. On the other hand, a sidelight type configuration (not shown) is used for a small- have.

The diffusion plate (lower diffusion sheet) is an optical sheet having a strong light diffusibility for reducing the in-plane brightness unevenness of the backlight light source (BLU) 6a.

The light condensing sheet is an optical sheet for condensing the diffused light in the front direction of the liquid crystal display device (the normal direction of the display device plane).

The upper diffusion sheet is used in order to reduce moiré caused by the periodic structure such as a prism sheet as a light condensing sheet or a pixel in a liquid crystal cell and an optical system used for further reducing in- Sheet.

As a display method of the liquid crystal cell, a transmissive mode of a mode such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), inflation switching (IPS), optical compensated bend cell Reflection type, or semi-transmission type liquid crystal display devices.

Examples of a light emission source used in a light source include CCFL (Cold Cathode Fluorescent Lamp), HCFL (Hot Cathode Fluorescent Lamp), LED (Light Emitting Diode), OLED (Organic light-emitting diode ), Organic light emitting diodes (organic EL), inorganic EL, and the like.

As shown in Fig. 2, the liquid crystal display device generally comprises a liquid crystal cell sandwiched between glass substrates and two polarizing plates PL1 and PL2 provided on both sides with the liquid crystal cell interposed therebetween. The polarizing plate disposed on the viewing side (upper side) of the polarizing plate is referred to as a viewing side polarizing plate PL1, and the polarizing plate disposed on the side of the light source (lower side) is referred to as a light source side polarizing plate PL2.

In the liquid crystal display device according to the present invention, the above-mentioned polarizing plate according to the present invention is used for the viewer-side polarizing plate PL1 and the light source-side polarizing plate PL2.

That is, the polarizing plate PL1 is composed of two optical films of a polarizer protective film 11a and a retardation film 9a sandwiching the polarizer therebetween. The polarizing plate PL2 is similarly constituted by sandwiching the polarizer 10a between the polarizer protective film 9b and the retardation film 11b. Here, the retardation film 9a and the retardation film 9b are arranged on the liquid crystal cell side.

In the liquid crystal display device according to the present invention, the thickness of the glass substrate for supporting and holding the liquid crystal cell is 0.6 mm or less. Even when the thickness of the glass substrate is reduced to 0.6 mm or less, the use of the polarizing plate according to the present invention makes it possible to suppress the warpage of the liquid crystal panel and to improve display irregularity.

<Examples>

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the examples, &quot; part &quot; or &quot;% &quot; is used, and unless otherwise stated, &quot; part by mass &quot;

<Production of Polarizer Protective Film 1>

(Preparation of dope)

Doped 1 of the following composition was prepared. First, methylene chloride and ethanol were added to the pressurization-dissolving tank. A cellulose ester resin and a plasticizer were added to a pressurized dissolution tank containing the solvent while stirring, and the mixture was heated and completely dissolved while stirring.

Cellulose ester resin 100 parts by mass

(Degree of substitution of aromatic acyl group: 0.7, aromatic acyl group type: benzoyl group, degree of aliphatic acyl group substitution of 2.2, aliphatic acyl group type: acetyl group, acyl group total degree of substitution: 2.9, Mw: 200000)

Plasticizer (polyester compound A-15 to be described later) 12 parts by mass

Methylene chloride 432 parts by mass

ethanol 38 parts by mass

 (Preparation of Polarizer Protective Film)

The prepared dope 1 was uniformly plied to the stainless steel band support at a temperature of 22 캜 and a width of 2 m by using a belt softener. In the stainless steel band support, the solvent was evaporated until the residual solvent amount became 100% by mass, and peeled off on the stainless steel band support with a peel tension of 162 N / m.

The peeled web was evaporated at 35 캜 to a slit of 1.6 m in width and then dried at a drying temperature of 135 캜 while being stretched 1.1 times in the width direction in the tenter. At this time, when the stretching was started in the tenter, the residual solvent amount was 10 mass%. After the film was stretched in a tenter, the film was relaxed at 130 캜 for 5 minutes. Then, the drying zone was transferred to a plurality of rolls at 110 캜 and 120 캜, and the film was slit with a width of 1.5 m. Knurled, and wound around a 6-inch inner core at an initial tension of 220 N / m and a final tension of 110 N / m to obtain a polarizer protective film 1. [

The draw ratio in the MD direction calculated from the rotating speed of the stainless steel band support and the running speed of the tenter was 1.1 times. The amount of the residual solvent in the polarizer protective film 1 was 0.1 mass%, the film thickness was 80 탆, and the number of windings was 4000 m.

(Plasticizer: Synthesis of polyester compound A-15)

The polyester compound A-15 described in paragraph [0160] of Japanese Patent Laid-Open Publication No. 2012-242546 was synthesized as follows.

830.7 g (5.0 mol) of phthalic acid as a main chain component, 730.7 g (5.0 mol) of adipic acid and 760.9 g (10 mol) of propanediol were added to a three liter four-necked flask equipped with a thermometer, a stirrer and a reflux condenser ), 1221.2 g (10 mol) of benzoic acid as an end constituent, and 0.10 g of tetraisopropyl titanate as an esterification catalyst. Subsequently, the mixture was refluxed under stirring in a nitrogen stream, and the temperature was elevated stepwise up to 220 DEG C, followed by dehydration condensation reaction at 220 DEG C for 15 hours. After completion of the reaction, the unreacted product was distilled off under reduced pressure to obtain a polyester compound A-15 (number average molecular weight Mn: 1100).

&Lt; Preparation of Polarizer Protective Films 2 to 27 >

Polarizer protective films 2 to 27 were prepared in the same manner as Polarizer protective film 1 except that the type of cellulose ester resin, the presence or absence of plasticizer and the finished film thickness were changed as shown in Table 1 below.

&Lt; Phase difference film 1 &

As the retardation film 1, ZEONOR40: Zeonoa film (cycloolefin film 40 mu m made by Nippon Zeon Co., Ltd.) was used.

&Lt; Production of retardation film 2 >

(Preparation of dope)

Doped 2 of the following composition was prepared. First, methylene chloride and ethanol were added to the pressurization-dissolving tank. The acrylic resin was poured into the pressurized dissolution tank containing the solvent while stirring, and the mixture was heated and completely dissolved while stirring.

Acrylic resin 100 parts by mass

(Acrylic resin (Mw: 100000) manufactured by Asahi Kasei Chemicals Co., Ltd.)

Methylene chloride 252 parts by mass

ethanol 48 parts by mass

(Preparation of retardation film)

Using the above-prepared Dope 2, the retardation film 2 having a thickness of 40 占 퐉 was prepared in the same manner as the polarizer protective film 1 was produced.

&Lt; Production of retardation film 3 >

In the production of the retardation film 2, the retardation film 3 was produced in the same manner except that the film thickness was 80 탆.

&Lt; Production of retardation film 4 >

A retardation film 4 similar to the retardation film 17 described in the paragraphs [0302] to [0319] described in Japanese Patent Application Laid-Open No. 2014-153444 was produced as follows.

(Preparation of fine particle dispersion)

11.3 parts by mass of fine particles (manufactured by Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) and 84 parts by mass of ethanol were mixed with a dissolver for 50 minutes and dispersed with mannitol.

(Preparation of fine particle addition liquid)

To 100 parts by mass of sufficiently stirred methylene chloride in the dissolution tank, 5 parts by mass of the fine particle dispersion was slowly added. In addition, the particles were dispersed in the attritor so that the particle size of the secondary particles became a predetermined size. The solution was filtered with Fine Mat NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle addition liquid.

(Preparation of dope)

Doped 4 of the following composition was prepared. First, methylene chloride and ethanol were added to the pressurization-dissolving tank. The cellulose ester A was added to the pressurized dissolution tank containing the solvent while stirring, and the solution was heated and completely dissolved while stirring.

Cellulose ester A 100 parts by mass

(Cellulose diacetate: acetyl group degree of substitution: 2.3, weight average molecular weight: Mw: 180000, DAC)

The particulate additive liquid 1 part by mass

The following plasticizer 1 12 parts by mass

Methylene chloride 300 parts by mass

ethanol 40 parts by mass

Further, the above additive component was put into a hermetically sealed container and dissolved with stirring, and this was filtered using Azumi-no. 244 manufactured by Azumi Co., Ltd. to prepare Dope 4.

(Preparation of retardation film)

The prepared dope 4 was uniformly plied to the stainless steel band support at a temperature of 22 캜 and a width of 1.5 m using a belt softener. In the stainless steel band support, the solvent was evaporated until the amount of residual solvent became 100%, and peeled off on a stainless steel band support with a peel tension of 162 N / m.

Subsequently, the web of the peeled Dope 1 was evaporated at 35 占 폚 and slit with a width of 1.3 m. Thereafter, the film was stretched 1.01 times in the conveying direction (MD direction) by stretching the web at 110 占 폚 at 110 占 폚, Direction) at a drying temperature of 135 캜 while stretching it to 1.3 times its original width. At this time, the amount of the residual solvent when the stretching by the tenter was started was 8%.

After the film was stretched by a tenter, the film was subjected to a relaxation treatment at 130 캜 for 5 minutes. Thereafter, the drying zone of 120 캜 and 140 캜 was transported by a plurality of rollers while the drying was completed. The film was slit at a width of 1.5 m, And 2.5 탆 in height, and then wound around a core to prepare a retardation film 4. The film thickness was 40 μm and the winding length was 4000 m.

<Production of Polarizer 1>

(Production of Polarizer)

A long roll of polyvinyl alcohol film having a thickness of 120 占 퐉 was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid and stretched at 50 占 폚 in the carrying direction by 5 times to prepare a polarizer.

(Production of polarizing plate)

1) The polarizer protective film 1 obtained above was soaked in a 2 mol / L aqueous sodium hydroxide solution at 60 占 폚 for 90 seconds, saponified, washed with water and dried.

2) The above-obtained retardation film 1 was subjected to corona discharge treatment by a known method, then saponified by immersing in a 2 mol / L sodium hydroxide aqueous solution at 60 DEG C for 90 seconds, washed with water and dried.

3) The polarizer was immersed in a polyvinyl alcohol adhesive solution having a solid content of 2% by mass for 1 to 2 seconds.

4) An excessive polyvinyl alcohol adhesive (watercolor) adhered to the polarizer was lightly wiped off, and a film saponified in the above 1) was placed on each side of the polarizer to form a laminate of the polarizer protective film 1 / polarizer / retardation film 1 Water was obtained.

5) The obtained laminate was bonded by a roll machine at a pressure of 20 to 30 N / m2 and a conveying speed of 2 m / min. The bonded laminate was dried at 60 ° C for 5 minutes to obtain a polarizing plate 1.

&Lt; Production of polarizing plates 2 to 27 >

Polarizing plates 2 to 13 and 15 to 27 were produced in the same manner as in the production of the polarizing plate 1 except that the polarizing plate protective film 1 and the retardation film 1 were changed to the combination of the respective films described in Table 3 below.

In the production of the polarizing plate 14, the polarizing plate 14 was produced in the same manner as in the production of the polarizing plate 1, except that the saponification treatment was performed without using the corona discharge treatment.

<Evaluation>

The following items were evaluated, and the results are shown in Tables 1 to 3.

(Measurement of the moisture permeability)

The obtained polarizer protective film and the retardation film were measured for moisture permeability.

The moisture permeability was measured by allowing the film to be measured to stand under the condition of 40 占 폚 and 90% RH for 24 hours based on the calcium chloride-cup method described in JIS Z 0208.

(Measurement of rate of dimensional change)

The dimensional change rate of the resulting polarizer protective film and retardation film was measured.

Two cross-shaped marks are displayed in the direction (MD direction) of bonding the film and the polarizer, and the film is allowed to stand for 24 hours under an environment of 23 占 폚 and 20% RH. Then, a distance L ₁ between two displays is measured do. Then, after the film allowed to stand for 24 hours under the environment of 23 ℃ and 80% RH, 2, like the dimensional change rate (%) by measuring the distance L ₂ between the two displays, the formula was calculated.

Dimensional change ratio (%) = (L ₂ / L ₁ -1) × 100

(productivity)

Ten sheets of each polarizing plate 1 to 27 were prepared in the same manner as in the production of the polarizing plate 1 to 27, the retardation film was peeled off from the polarizing plate, and the adhesive strength between the polarizing plate and the retardation film was measured. Respectively.

○: 0 out of 10 peeled off

△: 1 sheet out of 10 sheets peeled off

X: Peeled off two or more sheets out of 10 sheets

(Polarizer deterioration)

The polarization transmittance and the orthogonal transmittance of the polarizing plate produced above were measured first, and the degree of polarization was calculated according to the following formula. Thereafter, each polarizing plate was forcibly deteriorated for 1000 hours under the conditions of 60 DEG C and 90%, and then the parallel transmittance and the orthogonal transmittance were measured again, and the degree of polarization was calculated according to the following formula. The change in polarization degree was obtained by the following formula. The amount of change in polarization degree was evaluated as follows.

The degree of polarization P = ((H ₀ -H ₉₀ ) / (H ₀ + H ₉₀ )) 1/2 × 100

Polarization degree change amount = P ₀ -P ₁₀₀₀

H ₀ : Parallel transmittance

H ₉₀ : orthogonal transmittance

P ₀ : polarization degree before forced deterioration

P ₁₀₀₀ : polarization degree after 1000 hours of forced deterioration

?: Less than 25% change in polarization degree

X: 25% or more change rate of polarization degree

(Mounting on a liquid crystal display device)

The viewer-side polarizing plate and the light source-side polarizing plate of the front and back of a VA-mode liquid crystal TV (SONY BRAVIA W900A KDL-46W900A) were peeled off and used as a liquid crystal cell. The viewer-side polarizing plate and the polarizing plate produced above were used as the light-source-side polarizing plate of the liquid crystal display device using the vertically aligned liquid crystal cell.

The viewer-side polarizing plate and the light source-side polarizing plate were attached to the liquid crystal cell through a pressure-sensitive adhesive. The cross-Nicole arrangement was such that the transmission axis of the viewer-side polarizing plate was in the vertical direction and the transmission axis of the light source-side polarizing plate was in the horizontal direction.

(Bending of the liquid crystal panel)

The liquid crystal panel on which the polarizing plate prepared above was mounted was allowed to stand for 24 hours under an environment of 40 占 폚 and 95% RH, followed by 2 hours at 40 占 폚 and 20% RH, After 24 hours, the amount of warping of the liquid crystal panel was measured. The bending amount is evaluated in the following manner, and &amp; cir &amp;

A: No problem, no more than 0 mm and less than 1.0 mm, no irregularity due to warping

?: 1.0 to 2.0 mm, unevenness due to warpage occurs but it is unclear and does not stand out

X: more than 2.0 mm, unevenness due to warpage occurs, and it can be clearly recognized

(Measurement of display unevenness)

The liquid crystal panel mounted with the polarizing plate prepared above was allowed to stand for 24 hours under an environment of 40 占 폚 and 95% RH, followed by 2 hours at 40 占 폚 and dry, And the unevenness was observed from the front face of the liquid crystal panel after lighting. The display unevenness is evaluated as follows, and &amp; cir &amp;

A: It is difficult to recognize because there is no light leakage of the liquid crystal panel or light leakage is very weak

?: The light leakage appears on the liquid crystal panel, but the boundary is unclear and the light leakage is not remarkable

X: Light leakage is seen on the liquid crystal panel, and light leakage portions and non-light leakage portions can be clearly recognized

From the results shown in Table 3, it can be seen that the polarizer using the polarizer protective film and the retardation film according to the present invention has better productivity than the polarizer of the comparative example, can suppress the warp of the panel and can improve the display irregularity It is recognized.

&Lt; Industrial applicability >

INDUSTRIAL APPLICABILITY As described above, the present invention is suitable for providing a polarizing plate and a liquid crystal display device which are good in dryness at the time of sticking the watercolor, have good productivity, can suppress the warpage of the liquid crystal panel, Do.

1a: Light source
2a: luminescent light source
3a: diffusion plate (lower diffusion sheet)
4a: condensing sheet (prism sheet, lens sheet)
5a: upper diffusion sheet
6a: Backlight unit
7a: liquid crystal cell
8a: Transparent substrate (glass, plastic)
9a: phase difference film
9b: polarizer protective film
10a: Polarizer
11a: Polarizer protective film
11b: phase difference film
12a: a liquid crystal panel
PL1: visual side polarizer
PL2: polarizer on the light source side
1: melting pot
3, 6, 12, 15: filter
4, 13: stock tank
5, 14: Pump pump
8, 16: conduit
10: Ultraviolet absorber input kiln
20: junction pipe
21: Mixer
30: pressure die
31: metal belt
32: Web
33: Peeling position
34: Tenter stretching device
35: Roll dryer
37: Winding machine
41: Feeding kiln
42: stock kiln
43: pump
44: Filter

Claims (4)

A polarizer is provided between the polarizer protective film and the retardation film and the polarizer protective film and the retardation film are bonded to the polarizer in a water-
Wherein the polarizer protective film has a moisture permeability in a range of 200 to 2000 g / m 2 24 h after being left in an environment of 40 ° C. and 90% RH for 24 hours, and a dimensional change rate in a range of 23 ° C. to 20 to 80% RH Is in the range of 0.05 to 0.45%
Wherein the retardation film has a moisture permeability in a range of 0.1 to 100 g / m &lt; 2 &gt; 24h after being left in an environment of 40 DEG C and 90% RH for 24 hours. The polarizing plate according to claim 1, wherein the polarizer-protective film is a cellulose ester film having a substitution degree by an aromatic acyl group within a range of 0.4 to 1.5, and a total substitution degree by an aromatic acyl group and an aliphatic acyl group within a range of 2.6 to 3.0 Polarizing plate. The polarizing plate according to claim 1 or 2, wherein the retardation film is a film containing a cycloolefin resin. A liquid crystal display device having a liquid crystal cell sandwiched between glass substrates,
A polarizing plate according to any one of claims 1 to 3, further comprising:
Wherein a thickness of the glass substrate is 0.6 mm or less.

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