KR101634026B1 - Polarizing plate and display device using same - Google Patents

Abstract

Provided is a polarizing plate capable of suppressing occurrence of color unevenness at the time of panel display of a display device. A polarizing plate comprising a stretched laminate of a hydrophilic polymer layer and a base material layer comprising a thermoplastic resin and having a stretched laminate wherein the dichroic material is adsorbed to the hydrophilic polymer layer, characterized in that, under two environments of different temperature and humidity So that the fluctuation of the curl of the light emitting element becomes a value equal to or smaller than a predetermined value.

Description

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

The present invention relates to a polarizing plate and a display device using the same.

In recent years, technological innovation in the field of display devices has been remarkable, and development of display devices such as liquid crystal display devices and organic EL display devices has progressed, and many products have been launched.

As the method of the liquid crystal display device, well-known TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type and the like are well known. A liquid crystal display device generally includes a liquid crystal cell having a liquid crystal layer and a pair of substrates for supporting the liquid crystal layer therebetween, and a polarizing plate disposed on both sides (the viewer side and the backlight side) of the liquid crystal cell. Among them, IPS (In-Plane Switching) mode liquid crystal display devices (hereinafter, simply referred to as "IPS liquid crystal display devices") are currently widely used in portable devices such as tablet-type display devices and smart phones . In the IPS type liquid crystal display device, the liquid crystal molecules included in the liquid crystal layer are oriented parallel to the surfaces of the pair of substrates during black display, so that the IPS type liquid crystal display device has an advantage of excellent black display performance. In addition, an IPS type liquid crystal display device has an advantage that a high degree of viewing angle can be secured to some extent even if no so-called optical compensation film (viewing angle increasing film) is used. On the other hand, due to the optical characteristics of the liquid crystal cell included in the IPS liquid crystal display device, light leakage occurs when viewing the screen from the oblique direction, and the contrast of the display image is lowered.

In a liquid crystal display device, a retardation film is generally used for the purpose of preventing such deterioration of contrast, but a retardation film capable of coping with various optical designs has been required for further improvement of performance. Further, as for the phase difference film to be mounted on the portable device as described above, there is also a strong demand for further reduction in thickness and weight.

One of the important constituent members of the liquid crystal display device is a polarizing plate. The polarizing plate has a structure in which a polarizing plate and a polarizing plate protective film for protecting the polarizing plate are laminated. A so-called coating type polarizing plate is known as one type of polarizing plate, but this coating type polarizing plate has a problem that curling occurs under a humidifying environment. When curling occurs in the polarizing plate, display irregularity (color unevenness) locally occurs when the display device is constituted.

BACKGROUND ART Conventionally, as a technique capable of preventing curling even in a humidifying environment when a coating type polarizing plate is made thin, a technique has been proposed in which a hydrophilic polymer layer of a stretched laminate in which a laminate of a base layer and a hydrophilic polymer layer is stretched, A technique has been proposed in which a substance adsorbed thereon is used as a polarizing plate (see Patent Document 1). Here, in Patent Document 1, a polyolefin resin, a cyclic polyolefin resin and a (meth) acrylic resin are exemplified as preferable materials constituting the base layer. In the example of Patent Document 1, an example of using an acrylic resin film (a rocked polymethyl methacrylate film) or a norbornene resin film as a substrate layer is disclosed.

U.S. Patent Application Publication No. 2010/0202051

The inventors of the present invention have studied the technique described in the above-mentioned Patent Document 1. As a result, even when the polarizing plate is constituted by the technique described in Patent Document 1, it has been found that display unevenness (color unevenness) may occur when the display device is still constituted.

Accordingly, it is an object of the present invention to provide a polarizing plate capable of suppressing occurrence of color unevenness at the time of panel display of a display apparatus.

The present inventors have conducted extensive studies in view of the above problems. As a result, it has been found that a polarizing plate having a stretched laminate in which a laminate of a base layer containing a hydrophilic polymer layer and a thermoplastic resin is stretched and a dichroic substance is adsorbed on the hydrophilic polymer layer, The present inventors have found that the above problem can be solved by controlling the variation of the curl under the environment to be a value equal to or less than a predetermined value, thereby completing the present invention.

That is, the above object of the present invention can be achieved by the following arrangement.

1. A polarizing plate comprising a stretched laminate wherein a laminate of a base layer comprising a hydrophilic polymer layer and a thermoplastic resin is stretched and a dichroic material is adsorbed on the hydrophilic polymer layer,

A polarizing plate satisfying a difference? C = | C ₁ -C ₂ | between curl C ₁ under 23 ° C and 55% RH and curl C ₂ under 40 ° C and 20% RH environment satisfies? C? 80 [1 / m];

2. The polarizing plate according to the above 1, wherein the base layer contains at least two kinds of thermoplastic resins;

3. The polarizing plate according to the above 1 or 2, wherein the hydrophilic polymer layer has a film thickness of 0.5 to 30 占 퐉.

4. The thermoplastic resin composition according to any one of the above items 1 to 3, wherein the thermoplastic resin contained in the base layer comprises an acrylic resin, a styrene resin, a cycloolefin resin, a cellulose resin, a polypropylene resin, A polarizing plate described in the item 1;

5. The method according to claim 1,

A first base layer comprising a first thermoplastic resin,

4. The polarizing plate according to any one of 1 to 4 above, having a second base layer comprising a second thermoplastic resin disposed on the side opposite to the hydrophilic polymer layer with respect to the first base layer.

6. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the difference in the elastic modulus Ea of the first base layer and the modulus of elasticity Eb of the second base layer satisfies? E = | Ea-Eb | (MPa)

The difference in elastic modulus Ea ₁ and Eb ₁ under an environment of 23 ° C and 55% RH and the modulus of elasticity Ea ₂ and Eb ₂ under an environment of 40 ° C and 20% RH, ΔEa = | Ea ₁ -Ea ₂ | And? Eb = | Eb ₁ -Eb ₂ | satisfies? Ea and? Eb? 2000 [MPa].

7. The polarizing plate according to any one of items 1 to 6 above, wherein the stretched laminate has a thickness of 10 to 100 占 퐉.

8. The polarizing plate according to any one of the above 1 to 7, wherein the hydrophilic polymer layer comprises polyvinyl alcohol as a hydrophilic polymer.

9. The polarizing plate according to any one of the above 1 to 8, wherein the dichroic substance is iodine.

10. A process for producing a polarizing plate according to any one of 1 to 9 above,

A production method comprising a step of forming the base layer by a solution casting method;

11. The production method according to the above 10, further comprising a step of applying a solution containing a hydrophilic polymer on one surface of the base material layer thus formed and drying to obtain a laminate;

12. The production method according to the above 11, further comprising a step of stretching the laminate at a draw magnification of 2 to 10 times;

13. A polarizing plate according to any one of the above 1 to 9 or a polarizing plate produced by the manufacturing method according to any one of the above-mentioned 10 to 12;

14. The display device according to 13 above, which is an IPS mode liquid crystal display.

Hereinafter, embodiments of the present invention will be described in detail.

«Polarizer»

One aspect of the present invention relates to a polarizing plate having a stretched laminate in which a laminate of a hydrophilic polymer layer and a thermoplastic resin layer is stretched and a dichroic material is adsorbed on the hydrophilic polymer layer. The polarizing plate according to this embodiment has a curl C ₁ under an environment of 23 ° C and 55% RH and a difference ΔC = | C ₁ -C ₂ | from a curl C ₂ under an environment of 40 ° C and 20% RH, ] Is satisfied. According to the present invention, there is provided a polarizing plate capable of suppressing occurrence of color unevenness at the time of panel display of a display device.

The polarizing plate according to this embodiment has a stretched laminate in which a laminate of a hydrophilic polymer layer and a thermoplastic resin layer is stretched as described above and the dichroic material is adsorbed on the hydrophilic polymer layer. Hereinafter, the constituent elements of the stretched laminate will be described in more detail.

[Hydrophilic polymer layer]

The stretched laminate is first provided with a hydrophilic polymer layer. The hydrophilic polymer layer is a layer containing a hydrophilic polymer as a main component. In the polarizing plate according to this embodiment, the hydrophilic polymer layer absorbs a dichroic substance. Thus, the hydrophilic polymer layer functions as a polarizer in the polarizing plate according to this embodiment.

The hydrophilic polymer constituting the hydrophilic polymer layer is not particularly limited, but a polyvinyl alcohol-based material is preferably exemplified. Examples of the polyvinyl alcohol-based material include polyvinyl alcohol and derivatives thereof. Examples of the derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal and the like. In addition to these, olefins such as ethylene and propylene, unsaturated carboxylic acid glycol alkyl esters such as acrylic acid, methacrylic acid and crotonic acid, And the like. The degree of polymerization of polyvinyl alcohol is preferably about 100 to 10000, more preferably 1000 to 10000. A degree of saponification of about 80 to 100 mol% is generally used. In addition to the above, examples of the hydrophilic polymer include partially saponified ethylene / vinyl acetate copolymer, dehydrated polyvinyl alcohol, dehydrochlorinated polyvinyl chloride, and the like. As the hydrophilic polymer, polyvinyl alcohol is preferably used among the polyvinyl alcohol-based materials.

The hydrophilic polymer layer may contain an additive such as a plasticizer and a surfactant in addition to the above-described hydrophilic polymer. Examples of the plasticizer include polyols and condensates thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of plasticizer and the like to be used is not particularly limited, but is preferably 20% by mass or less based on 100% by mass of the total amount of the hydrophilic polymer layer.

The specific constitution of the dichroic substance adsorbed on the hydrophilic polymer layer is not particularly limited, and examples thereof include iodine and organic dyes. Examples of organic dyes include red dyes such as Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Black Blue, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct Sky Blue, Direct Fast Orange S, First Black, and the like can be used. Among them, iodine is preferably used as the dichroic material from the viewpoint of water solubility and process suitability. These dichroic substances may be used alone, or two or more of them may be used in combination.

The adsorption amount of the dichroic substance in the hydrophilic polymer layer is not particularly limited, and can be suitably set with reference to conventionally known knowledge.

The thickness of the hydrophilic polymer layer after stretching is not particularly limited, but is preferably 0.5 to 30 占 퐉, and more preferably 1 to 10 占 퐉. If the thickness is a value lower than the lower limit value, the influence of the thickness variation at the time of manufacturing becomes smaller, and appearance defects are less likely to occur. On the other hand, if the thickness is less than the upper limit value, there is an advantage that the dryness of the aqueous solution is improved and the productivity is improved. As the value of the thickness of the hydrophilic polymer layer, a value measured by subtracting the thickness of the stretched film from the thickness of the stretched laminate only under the same condition as that of the base film alone is adopted. The thickness is measured by using a film thickness meter or the like.

[Base layer]

The oriented laminate further comprises a base layer. The base layer can function as a base material for producing the hydrophilic polymer layer in the production of the stretched laminate (polarizing plate). The base layer functions as a protective layer (protective film) for protecting the polarizer in the polarizing plate according to this embodiment. Further, another layer may be formed between the base layer and the hydrophilic polymer layer, if necessary.

The base layer comprises a thermoplastic resin. There is no particular limitation on the thermoplastic resin contained in the base layer, and any material that can attain? C of the above-mentioned polarizing plate can be used. Preferably, the base layer is composed of a stretchable thermoplastic resin. Examples of the stretchable thermoplastic resin include an acrylic resin, a styrene resin, a cycloolefin resin, a cellulose resin, a polypropylene resin, a polyester resin, or a combination thereof. At this time, as the acrylic resin, an acrylic resin containing a constituent unit derived from methyl methacrylate as a main component and further containing a constituent unit derived from a monomer component copolymerizable therewith is preferably used. Examples of copolymerizable monomer components include acrylic acid derivatives having a cyclic structure. The styrene-based resin includes a styrene-based resin containing a styrene-derived structural unit as a main component and further containing a structural unit derived from a monomer component copolymerizable therewith. Examples of the cycloolefin-based resin include a norbornene-based resin referred to as a cycloolefin-based self-polymer. Examples of the polypropylene resin include polypropylene other than polypropylene and polypropylene including a part of polyethylene, and examples of the polyester resin include polyethylene terephthalate (PET) and the like.

Among them, in the preferred embodiment, the substrate layer contains a cellulose resin. The specific form of the cellulose resin is not particularly limited, but a cellulose resin polymerized in the presence of a cellulose ester, a cellulose ether, a cationized cellulose, various vinyl monomers and the like, a graft polymer with various vinyl monomers and the like are used. Among them, a cellulose ester resin is particularly preferably used.

The specific form of the cellulose ester resin is not particularly limited. In particular, from the viewpoints of improvement in brittleness and transparency, the following formulas (1) to (3):

In the formulas, A represents the degree of substitution of the acetyl group, and B represents the total degree of acyl group substitution of 3 to 7 carbon atoms.

Is preferably an acyl group having a substitution degree satisfying the relationship of

When the total substitution degree (A + B) of the acyl group having 2 to 7 carbon atoms in the cellulose ester resin is 2.0 or more (that is, when the residues of the hydroxyl groups at the 2, 3 and 6 positions in the cellulose ester molecule are 1.0 or less) The increase in haze is prevented even when the protective film functions as a protective film. When the degree of substitution (A + B) of the acyl group is 2.0 or more and the degree of substitution of the acyl group having 3 to 7 carbon atoms is 1.0 or more, the lowering of the brittleness is prevented.

The acyl group substitution degree of the cellulose ester resin is such that the degree of substitution (A) is 2.0 to 3.0, the degree of substitution (A) of the acetyl group is 0.15 to 2.0, the degree of substitution (B) of the acyl group having 3 to 7 carbon atoms But it is preferable that the total degree of substitution of an acyl group having a carbon number other than 3 to 7, that is, an acetyl group or an acyl group having a carbon number of 8 or more, is 1.3 or less. Further, the total substitution degree (A + B) of the acyl group having 2 to 7 carbon atoms in the cellulose ester resin is more preferably in the range of 2.5 to 3.0.

The acyl group may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or branched and may have a substituent. The carbon number of the acyl group in the present invention includes a substituent of an acyl group.

When the cellulose ester resin has an aromatic acyl group as a substituent, it is preferable that the number of the substituent X substituted with an aromatic ring is 0 to 5. Also in this case, in the above-mentioned preferred embodiments, it is necessary to make the substitution degree of the acyl group having 3 to 7 carbon atoms including the substituent to be 1.0 to 2.75. For example, when the benzoyl group has a carbon number of 7, when it has a substituent containing carbon, the number of carbon atoms as the benzoyl group is 8 or more, and it is not included in the acyl group having 3 to 7 carbon atoms.

When the number of the substituents to be substituted with an aromatic ring is two or more, they may be the same or different from each other and may be mutually connected to form a condensed polycyclic compound (for example, naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, Male, chroman, phthalazine, acridine, indole, indoline and the like).

The cellulose ester resin is preferably at least one selected from cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate. Of these, particularly preferred cellulose ester resins are cellulose acetate propionate and cellulose propionate. In the present invention, two or more kinds of cellulose ester resins may be mixed and used.

Further, the part not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by a known method. The substitution degree of the acetyl group and the substitution degree of the other acyl group are obtained by the method defined in ASTM-D817-96.

The weight average molecular weight (Mw) of the cellulose ester resin is preferably 75000 or more, more preferably 75000 to 300000, further preferably 100000 to 240000, and most preferably 160000 to 240000 Is particularly preferable. When the weight average molecular weight (Mw) of the cellulose ester resin is less than 75,000, there is a possibility that the effect of improving the heat resistance and the brittleness may not be sufficiently obtained.

The thickness of the base layer constituting the oriented laminate is not particularly limited, but is preferably 10 to 200 占 퐉, and more preferably 20 to 80 占 퐉. When the thickness is the lower limit value or more, the strength as a polarizing plate is sufficiently secured. On the other hand, if the thickness is not more than the upper limit value, curling of the polarizing plate can be further prevented. As the value of the thickness of the base layer, a value obtained by preparing a film obtained by stretching only the base film under the same conditions, and measuring the thickness thereof is adopted.

The water absorption rate of the substrate layer when impregnated in water at 23 DEG C for 24 hours is preferably 1.0 to 8.0% by mass. The water absorption rate is preferably 2.0 to 5.0 mass%, and more preferably 3.0 to 5.0 mass%. As the value of the water absorption of the substrate layer, a value measured by the following method is adopted.

(Method for Measuring Absorption Rate of Substrate Layer)

Only the base layer is separated from the stretched laminate, and the base layer is impregnated in water at 23 占 폚 for 24 hours, then pulled up from water to measure the mass (M1) of the base layer. Subsequently, the substrate layer is allowed to stand at 23 DEG C and 55% RH for 24 hours, and then the mass (M0) of the substrate layer is measured. From this measurement result, the absorption rate is calculated according to the following equation (4).

It is possible to more reliably suppress occurrence of display unevenness at the time of panel display of the display apparatus by constituting a stretched laminated body with a hydrophilic polymer layer using a base layer having an absorption coefficient satisfying the above-mentioned requirements.

The specific form of the cellulose ether resin is not particularly limited, but it has an ether bond in at least one of the 2, 3, and 6 positions in the cellulose molecule. The ether bond referred to herein is a carbon-oxygen-carbon bond. Examples of the cellulose ether include, but are not limited to, methylcellulose, ethylcellulose, carboxymethylcellulose, carboxymethylethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose and the like. In order to ensure transparency and durability as optical films, ethylcellulose is the most suitable. The degree of substitution of ethoxyl is preferably in the range of 1.9 to 2.9, and particularly preferably in the range of 2.2 to 2.9 from the balance of the viscosity at the time of melting and the stability of the anti-wet heat environment. Further, the degree of ether substitution can be quantified by the method described in ASTM D4794-94. The molecular weight of the cellulose ether is not particularly limited as long as it can be made into a film by itself. Specifically, the number average molecular weight Mn may be in the range of 30,000? Mn? 300,000 (in terms of polystyrene), more preferably 50,000 to 200,000 do. If the molecular weight is too small, the film becomes brittle, and if the molecular weight is too high, the viscosity is high and the molding stability at the time of molding is deteriorated.

In a preferred embodiment of the present invention, the base layer comprises at least two thermoplastic resins. In this embodiment, it is preferable that at least two kinds of thermoplastic resins contained in the substrate layer essentially include a cellulose ester resin and an acrylic resin, and it is particularly preferable that the thermoplastic resin includes only two kinds of these.

Examples of the form in which the base layer contains two or more kinds of thermoplastic resins include (i) a form in which two or more kinds of thermoplastic resins constitute a base layer of one layer of a homogeneous composition as a mixture in a commercial state, (ii) (Iii) a form in which these (i) and (ii) are combined, and the like.

(i) As this form, for example, a form in which a cellulose ester resin and an acrylic resin are contained in a state of being mixed is exemplified. For such forms, reference can be made to the pamphlet of International Publication No. 2011/121720 or the contents of the international publication No. 2011/121817 pamphlet.

There is no particular limitation on the form (ii), and any form in which a base layer containing any one of the above-described thermoplastic resins and a base layer containing a thermoplastic resin different from the above-mentioned thermoplastic resin are laminated is adopted . However, from the viewpoint of ensuring adhesion with the hydrophilic polymer layer, it is preferable that a base layer (also referred to as " first base layer " in the present specification) located on the hydrophilic polymer layer side among the base layers of other laminated compositions is a cellulose resin (Referred to as " second base layer " in the present specification) containing an acrylic resin (preferably a cellulose ester resin) and located on the side opposite to the hydrophilic polymer layer.

In a preferred embodiment, the difference ΔE = | Ea-Eb | (MPa) between the elastic modulus Ea of the first base layer and the elastic modulus Eb of the second base layer preferably satisfies ΔE ≦ 3,000 [MPa] ? 2500 is more preferable, and it is more preferable that? E? 2000 is satisfied. Further, when the elastic modulus Ea and Eb under as the elastic modulus Ea and Eb under 23 ℃ 55% RH environment, each Ea _1, and Eb ₁ and, 40 ℃ 20% RH environment la each Ea ₂ and Eb _2, the Ea and Eb Each difference? Ea = | Ea ₁ -Ea ₂ | And Eb = Eb ₁ -Eb ₂ | preferably satisfy? Ea and? Eb? 2000 [MPa], more preferably satisfy? Ea and? Eb? 1500, and more preferably satisfy? Eb? 1000 . It is also a more preferable embodiment that the above-mentioned? E satisfies the preferable rule and? Ea and? Eb satisfy both the preferable rules. As the values of the modulus of elasticity of the first base layer and the second base layer, a value measured by the method described in the column of the following example is employed. In order to control the values of the modulus of elasticity of the first base layer and the second base layer, the stretching magnification, the stretching speed, the temperature at the time of stretching, the humidity at the time of stretching, and the like may be appropriately controlled at the time of manufacturing the base layer.

The substrate layer may contain various additives in addition to the above-mentioned thermoplastic resin.

≪ Low molecular weight acrylic polymer &

As an additive that can be added to the base layer, first, a low molecular weight acrylic polymer can be mentioned. The weight average molecular weight (Mw) of the low molecular weight acrylic polymer is preferably 500 to 30,000. (X ₁ ) having a weight average molecular weight of 500 to 30000 obtained by polymerizing an ethylenically unsaturated monomer (Xa) having no aromatic ring and a hydrophilic group in the molecule among the low molecular weight acrylic polymer, or an ethylene (meth) acrylate those containing an unsaturated monomer (Xa) and the ethylenically unsaturated monomer polymer (X ₂₎ of the weight average molecular weight of 500 to 30,000 obtained by copolymerizing, (Xb) having a hydrophilic group does not have an aromatic ring in the molecule is preferred. Examples of the ethylenically unsaturated monomer (Xa) having no aromatic ring and hydrophilic group in the molecule include (meth) acrylic acid esters as described later, and among them, methyl methacrylate (MMA) is particularly preferable. Examples of the ethylenically unsaturated monomer (Xb) having no hydrophilic group in the molecule and having no aromatic ring include acryloylmorpholine, vinylpyrrolidone, and hydroxyethylmethacrylate. The content ratio of the constituent unit derived from Xa to the constituent unit derived from Xb in X ₂ is not particularly limited, but the proportion of the constituent unit derived from the constituent unit derived from Xa: Xb is preferably 50:50 to 95: 5 , More preferably 60:40 to 90:10, and particularly preferably 70:30 to 80:20.

The weight average molecular weight of the acrylic polymer is preferably 1500 to 20,000, more preferably 2,000 to 10,000, and particularly preferably 2,500 to 5,000. When the weight average molecular weight of the acrylic polymer is within this range, there is an advantage that it is easy to balance the volatility and compatibility.

The content of the above-mentioned acrylic polymer in the base layer is preferably 10 to 40 mass%, more preferably 20 to 30 mass%, based on 100 mass% of the thermoplastic resin. When the base layer is formed of a laminate of a plurality of base layers, the content is a mass ratio to the total amount of the thermoplastic resins constituting the base layer containing the additive (s).

Examples of the additives other than the low molecular weight acrylic polymer include plasticizers, sugar ester compounds, retardation adjusting agents, colorants and the like.

<Plasticizer>

The specific form of the plasticizer is not particularly limited, and for example, a polyester plasticizer can be mentioned. The specific structure of the polyester-based plasticizer is not particularly limited, and a polyester-based plasticizer having an aromatic ring or a cycloalkyl ring in the molecule can be used. Examples of the polyester-based plasticizer include a polyester compound represented by the following formula (4).

And the like.

In formula (4), B represents a straight-chain or branched alkylene group or cycloalkylene group having 2 to 6 carbon atoms, and A represents an aromatic ring having 6 to 14 carbon atoms or a linear or branched alkyl group having 2 to 6 carbon atoms X represents a hydrogen atom or a monocarboxylic acid residue containing an aromatic ring having 6 to 14 carbon atoms, and n represents a natural number of 1 or more.

The polyester compound represented by the formula (4) can be produced by reacting a dicarboxylic acid having an aromatic ring (carbon number 6 to 14) or a linear or branched alkylene group or cycloalkylene group (all of which have 2 to 6 carbon atoms) Is an alternating copolymer obtained by alternating copolymerization of a linear or branched alkylene diol or cycloalkylene diol. The aromatic dicarboxylic acid and the dicarboxylic acid having a straight chain or branched alkylene group or cycloalkylene group may be used either singly or as a mixture, but a resin of the main component constituting the polarizing plate protective film (for example, Cellulose ester resin), it is preferable that at least 10% or more of the aromatic dicarboxylic acid is contained. Further, both ends may be sealed with a monocarboxylic acid having an aromatic ring (carbon number of 6 to 14).

Examples of the dicarboxylic acid having an aromatic ring (carbon number of 6 to 14), that is, an aromatic dicarboxylic acid having 6 to 16 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalene dicarboxylic acid, , 4-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,8- , 2'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and the like. Among them, terephthalic acid, 2,6-naphthalene dicarboxylic acid and 4,4'-biphenyldicarboxylic acid are preferable.

Examples of the dicarboxylic acid having a linear or branched alkylene group or a cycloalkylene group (having 2 to 6 carbon atoms) include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, -Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like. Among them, succinic acid, adipic acid and 1,4-cyclohexanedicarboxylic acid are preferable.

Examples of the straight chain or branched alkylene diol or cycloalkylene diol having 2 to 6 carbon atoms include ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and the like. Among them, ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol and 1,3-butanediol are preferable.

Among them, A is preferably a benzene ring, naphthalene ring or biphenyl ring which may have a substituent, from the viewpoint of excellent plasticity-imparting performance. Here, the "substituent" that the benzene ring, naphthalene ring or biphenyl ring may have is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

Examples of the monocarboxylic acid having an aromatic ring (having 6 to 14 carbon atoms) for sealing both ends of the polyester compound include benzoic acid, orthotoluic acid, meta-toluic acid, para-toluic acid, para- Benzoic acid, and para-methoxybenzoic acid. Among them, benzoic acid, para-toluic acid and para-tert-butylbenzoic acid are preferable.

The aromatic polyester compound can be obtained by a conventional method such as a thermal melt condensation method by the polyesterification reaction or transesterification reaction of the above-mentioned dicarboxylic acid and an alkylene diol or cycloalkylene diol, or the acid chloride, Can be easily synthesized by any one of the interfacial condensation methods. By adding the above-mentioned aromatic monocarboxylic acid, a polyester compound having both ends sealed can be synthesized.

The aromatic polyester compounds that can be used in the present invention are exemplified below.

The substrate layer may further contain a plasticizer other than the polyester compound represented by the formula (4).

The plasticizer other than the polyester compound represented by the formula (4) is not particularly limited, but preferably a polyvalent carboxylic acid ester plasticizer, a glycolate plasticizer, a phthalate ester plasticizer, a fatty acid ester plasticizer and a polyhydric alcohol ester plasticizer , Ester plasticizers, acrylic plasticizers, and the like.

When two or more plasticizers are used, at least one of them is preferably a polyhydric alcohol ester plasticizer.

The polyhydric alcohol ester plasticizer is preferably a plasticizer comprising an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and has an aromatic ring or a cycloalkyl ring in the molecule. Preferably 2 to 20, aliphatic polyhydric alcohol esters.

The polyhydric alcohol preferably used in the present invention is represented by the following formula (a).

(Wherein R ₁₁ is an organic group of n, n is a positive integer of 2 or more, and the OH group is an alcoholic and / or phenolic hydroxy group (hydroxyl group).

Examples of preferred polyhydric alcohols include, but are not limited to, the following.

Propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,2-butanediol, 1,2-butanediol, 1,3-propanediol, Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylol propane, trimethylol ethane, xylitol and the like.

Particularly preferred are triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylol propane and xylitol.

The monocarboxylic acid used in the polyhydric alcohol ester is not particularly limited and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, aromatic monocarboxylic acids and the like can be used. The use of an alicyclic monocarboxylic acid or an aromatic monocarboxylic acid is preferable because it improves the moisture permeability and retention.

Examples of preferred monocarboxylic acids include, but are not limited to, the following.

As the aliphatic monocarboxylic acid, a linear or branched chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms. Incorporation of acetic acid increases compatibility with cellulose acetate, and it is preferable to use acetic acid and other monocarboxylic acids in combination.

Preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanoic acid, undecanoic acid, But are not limited to, trimellitic acid, trimellitic acid, decyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, , Saturated fatty acids such as lactic acid, undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid and derivatives thereof.

Examples of preferable aromatic monocarboxylic acids include those obtained by introducing one to three alkoxy groups such as alkyl groups, methoxy groups or ethoxy groups into benzene rings of benzoic acids such as benzoic acid and toluic acid, those having biphenylcarboxylic acid and naphthalenecarboxylic acid , Tetralin carboxylic acid and the like, or an aromatic monocarboxylic acid having two or more benzene rings or derivatives thereof. Particularly preferred is benzoic acid.

The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably 300 to 1500, more preferably 350 to 750. [ A larger molecular weight is preferable because it is less volatile, and the water permeability and the compatibility with cellulose acetate are preferably small.

The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. In addition, the OH group in the polyhydric alcohol may be all esterified, or a part thereof may be left as an OH group.

Specific compounds of polyhydric alcohol esters are exemplified below.

The glycolate-based plasticizer is not particularly limited, but alkyl phthalyl alkyl glycolates can be preferably used.

The alkyl phthalyl alkyl glycolates include, for example, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octylphthalyl octyl glycolate, Ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octylphthalyl methyl glycolate, and octylphthalyl ethyl glycolate.

Examples of the phthalate ester plasticizers include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexylterephthalate, .

Examples of the citrate ester plasticizer include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyl tributyl citrate.

Examples of the fatty acid ester plasticizer include butyl oleate, methyl acetyl ricinolate, dibutyl sebacate, and the like.

Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

The polycarboxylic acid ester compound includes an ester of a polyvalent carboxylic acid and an alcohol having a valence of 2 or more, preferably 2 to 20, The aliphatic polycarboxylic acid is preferably 2 to 20 carbon atoms, and in the case of an aromatic polycarboxylic acid or an alicyclic polycarboxylic acid, it is preferably 3 to 20 carbon atoms.

The polycarboxylic acid is represented by the following formula (b).

In the formula, R ₁₂ is (m1 + n1) valent organic group, m1 is a positive integer of 2 or more, n1 is an integer, 0 or more COOH groups are carboxyl group, OH group represents an alcoholic or phenolic hydroxyl group.

Examples of preferred polyvalent carboxylic acids include, but are not limited to, the following.

Aromatic polycarboxylic acids or derivatives thereof having three or more valences such as trimellitic acid, trimesic acid and pyromellitic acid, aliphatic polycarboxylic acids or derivatives thereof such as succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid and tetrahydrophthalic acid Oxycarboxylic acids such as polycarboxylic acids, tartaric acid, tartronic acid, malic acid and citric acid may be preferably used. Particularly, it is preferable to use an oxydarboxylic acid in view of improvement in retention property and the like.

The alcohol used in the polyvalent carboxylic acid ester compound usable in the present invention is not particularly limited and known alcohols and phenols can be used.

For example, aliphatic saturated alcohols or aliphatic unsaturated alcohols having 1 to 32 carbon atoms may be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 10 carbon atoms.

In addition, alicyclic alcohols such as cyclopentanol and cyclohexanol or derivatives thereof, aromatic alcohols such as benzyl alcohol and cinnamyl alcohol, and derivatives thereof may also be preferably used.

When an oxydarboxylic acid is used as the polycarboxylic acid, the alcoholic or phenolic hydroxyl group (hydroxyl group) of the oxydarboxylic acid may be esterified using a monocarboxylic acid. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

As the aliphatic monocarboxylic acid, a linear or branched chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 10 carbon atoms.

Preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, undecylic acid, But are not limited to, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, myristic acid, pentadecylic acid, palmitic acid, Unsaturated fatty acids such as maleic acid, maleic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid and derivatives thereof.

Examples of preferred aromatic monocarboxylic acids include those obtained by introducing an alkyl group into a benzene ring of a benzoic acid such as benzoic acid or toluic acid, a benzene ring such as biphenylcarboxylic acid, naphthalenecarboxylic acid or tetralinecarboxylic acid, Or an aromatic monocarboxylic acid or a derivative thereof. Particularly preferred are acetic acid, propionic acid and benzoic acid.

Although the molecular weight of the polycarboxylic acid ester compound is not particularly limited, it is preferably in the range of 300 to 1000, more preferably in the range of 350 to 750. It is preferable to be large in terms of improvement in retention property and small in terms of compatibility with the moisture-permeable, cellulose-based resin.

The alcohols used in the polyvalent carboxylic acid ester which can be used in the present invention may be one kind or a mixture of two or more kinds.

The acid value of the polyvalent carboxylic acid ester compound usable in the present invention is preferably 1 mgKOH / g or less, more preferably 0.2 mgKOH / g or less. By setting the acid value in the above range, fluctuation of the environment of retardation is suppressed, which is preferable.

The term "acid" refers to the number of milligrams of potassium hydroxide necessary to neutralize the acid contained in 1 g of the sample (the carboxyl group present in the sample). The acid value is measured in accordance with JIS K0070.

Examples of particularly preferable polyvalent carboxylic acid ester compounds are shown below, but the present invention is not limited thereto.

For example, there may be mentioned triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyltriphenyl citrate, acetyl tribenzyl citrate, Dibutyl tartarate, diacetyl dibutyl tartrate, tributyl trimellitate, tetrabutyl pyromellitate, and the like.

The plasticizer is preferably contained in an amount of 0.1 to 30 mass%, more preferably 2 to 20 mass%, based on 100 mass% of the total amount of the substrate layer.

&Lt; Diester compound &

Since the substrate layer further contains a sugar ester compound, hydrolysis of the cellulose ester resin is prevented, and the water resistance of the film can be improved.

An example of the sugar ester compound is a compound represented by the following formula (5):

And the like.

In the formula (5), Q represents a residue of a monosaccharide or a disaccharide, R represents an aliphatic group or an aromatic group, m is a total number of hydroxyl groups directly bonded to a residue of a monosaccharide or a disaccharide, (OC (= O) -R) group directly bonded to a residue of a monosaccharide or a disaccharide, and 3? M + l? 8, and l?

It is difficult to isolate the compound having the structure represented by the formula (5) as a single kind of compound in which the number of hydroxyl groups (m) and the number of - (OC (= O) It is known that a compound in which several kinds of other components of m and l are mixed is known. Therefore, the performance as a mixture in which the number of hydroxyl groups (m) and the number of - (OC (= O) -R groups) is respectively changed is important. In the case of the cellulose acylate film of this embodiment, A compound having a structure represented by the formula (5) and a mixing ratio of a component of m = 0 and a component of m > 0 of 45:55 to 0: 100 is preferable. In terms of performance and cost, more preferably, the mixing ratio of the component of m = 0 to the component of m > 0 is in the range of 10:90 to 0.1: 99.9. In addition, the components of m = 0 and the components of m > 0 can be measured by high performance liquid chromatography by a conventional method.

In the above formula (5), Q represents a residue of a monosaccharide or a disaccharide. Specific examples of monosaccharides include, for example, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose and ricin.

Examples of the structure of the compound having a monosaccharide residue represented by the formula (5) are shown below, but the present invention is not limited to these specific examples.

Specific examples of the disaccharide include trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, isotrehalose and the like.

Examples of the structure of the compound having a disaccharide residue represented by the formula (5) are shown below, but the present invention is not limited to these specific examples.

In the formula (5), R represents an aliphatic group or an aromatic group. Here, the aliphatic group and the aromatic group may each independently have a substituent.

In the formula (5), m is a total number of hydroxyl groups directly bonded to monosaccharides or disaccharide residues, and 1 is directly bonded to monosaccharide or disaccharide moieties - (OC (= O) -R ) Is the sum of the numbers of groups. And, 3? M + l? 8 is required, and 4? M + l? 8 is preferable. L &lt; / RTI &gt; When l is 2 or more, the - (O-C (= O) -R) groups may be the same or different.

The aliphatic group in the definition of R may be linear, branched or cyclic, preferably 1 to 25 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 2 to 15 carbon atoms. Specific examples of the aliphatic group include linear or branched aliphatic groups such as methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, Cyclohexyl, n-heptyl, n-octyl, bicyclooctyl, adamantyl, n-decyl, tert-octyl, dodecyl, hexadecyl, octadecyl and didecyl.

The aromatic group in the definition of R may be an aromatic hydrocarbon group, an aromatic heterocyclic group, or more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include benzene, naphthalene, anthracene, biphenyl, terphenyl, and the like. As the aromatic hydrocarbon group, benzene, naphthalene and biphenyl are particularly preferable. The aromatic heterocyclic group preferably contains at least one of an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of the heterocycle include, for example, 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, pyridine, triazine, and quinoline are particularly preferable.

Next, preferred examples of the compound represented by the formula (5) are shown below, but the present invention is not limited to these specific examples.

(Synthesis Example: Synthesis Example of Compound Represented by Formula (5)) [

34.2 g (0.1 mol) of sucrose, 180.8 g (0.8 mol) of anhydrous benzoic acid, and 379.7 g (4.8 mol) of pyridine were fed into 4-necked colbane equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introducing tube, The temperature was raised while bubbling nitrogen gas through a nitrogen gas introducing tube, and the esterification reaction was carried out at 70 DEG C for 5 hours. Subsequently, the internal pressure of collven was reduced to 4 × 10 ² Pa or less, excess pyridine was distilled off at 60 ° C., the pressure in corbene was reduced to 1.3 × 10 Pa or less, and the temperature was raised to 120 ° C. to obtain an anhydrous benzoic acid Most were distilled off. Subsequently, 300 g of an aqueous solution of sodium carbonate of 0.5% by mass in 1 L of toluene was added, stirred at 50 캜 for 30 minutes, and then allowed to stand to separate the toluene layer. Finally, 100 g of water was added to the separated toluene layer, and the mixture was washed with water at room temperature for 30 minutes. Then, the toluene layer was collected and toluene was distilled off at 60 캜 under reduced pressure (4 × 10 ² Pa or less) , Exemplified Compound 2, Exemplified Compound 3, Exemplified Compound 4, and Exemplified Compound 5 were obtained. Analysis of the obtained mixture by HPLC and LC-MASS showed that 7 mass% of Exemplified Compound 1, 58 mass% of Exemplified Compound 2, 23 mass% of Exemplified Compound 3, 9 mass% of Exemplified Compound 4, 3 mass of Exemplified Compound 5 %. Further, a part of the resulting mixture was purified by silica gel column chromatography to give Exemplary Compound 1, Exemplified Compound 2, Exemplified Compound 3, Exemplified Compound 4 and Exemplified Compound 5, each having a purity of 100%.

The sugar ester compound is preferably contained in an amount of 0.1 to 30 mass%, more preferably 2 to 20 mass%, based on 100 mass% of the total amount of the substrate layer.

<Retardation Control Agent>

The base layer may contain a retardation adjusting agent. The retardation adjusting agent is an additive capable of adjusting the retardation development property of the film by the addition thereof. There is no particular limitation on the specific configuration thereof, and conventionally known knowledge can be appropriately referred to. Also, there is a retardation adjustment scheme that simultaneously has the effect of adjusting the wavelength dispersion, and this may be used.

Examples of the retardation adjusting agent that can be used in the present invention include aromatic compounds having two or more aromatic rings as described in European Patent No. 911,656 A2. Two or more kinds of aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring. It is particularly preferred that the aromatic heterocycle is an aromatic heterocycle, and the aromatic heterocycle is generally an unsaturated heterocycle. Among them, a compound having a 1,3,5-triazine ring is particularly preferable.

As another example of the retardation adjusting agent, there may be mentioned the compounds disclosed as formula (I) in JP-A-2010-163482. Specific examples of the formula (I) are disclosed in paragraphs &quot; 0052 &quot; to &quot; 0058 &quot;. Further, the compound disclosed as the chemical formula (I) in JP-A-2010-163483 can also be similarly used as a retardation-adjusting agent. Specific examples of the formula (I) are disclosed in paragraphs &quot; 0054 &quot; to &quot; 0068 &quot;

The retardation adjusting agent is preferably contained in an amount of 0.1 to 30 mass%, more preferably 2 to 20 mass%, based on 100 mass% of the total amount of the substrate layer.

<Polyester>

It is also preferable that the substrate layer contains the following polyester.

(The polyester represented by the formula (d) or (e)

The base layer may include a polyester represented by the following formula (d) or (e).

(Wherein B1 represents a monocarboxylic acid, G represents a bivalent alcohol, A represents a dibasic acid, B1, G and A all do not contain an aromatic ring, and m represents a repeating number)

(Wherein B2 represents a monoalcohol, G represents a bivalent alcohol, A represents a dibasic acid, B2, G and A all do not contain an aromatic ring, and n represents a repeating number)

In the formulas (d) and (e), B1 represents a monocarboxylic acid component, B2 represents a monoalcohol component, G represents a bivalent alcohol component, A represents a dibasic acid component, Synthesized. B1, B2, G, and A do not include an aromatic ring. m and n represent the number of repeats.

The monocarboxylic acid represented by B1 is not particularly limited and known aliphatic monocarboxylic acids and alicyclic monocarboxylic acids can be used.

Examples of preferred monocarboxylic acids include, but are not limited to, the following.

As the aliphatic monocarboxylic acid, a linear or branched chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 12 carbon atoms. Incorporation of acetic acid increases compatibility with cellulose acylate, and therefore, it is also preferable to use acetic acid and other monocarboxylic acids in combination.

Examples of preferred aliphatic monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, But are not limited to, acetic acid, succinic acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, Saturated fatty acids such as carbonic acid, melissic acid, and lactic acid; Unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

The monoalcohol component represented by B2 is not particularly limited and known alcohols can be used. For example, aliphatic saturated alcohols or aliphatic unsaturated alcohols having a straight-chain or branched side chain having 1 to 32 carbon atoms can be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 12 carbon atoms.

Examples of the dihydric alcohol component represented by G include the following, but the present invention is not limited thereto. Examples of the solvent include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, , Pentanediol, 1,6-hexanediol, 1,5-pentylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and the like. Of these, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, diethylene glycol and triethylene glycol are preferable, , 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, and diethylene glycol are preferably used.

As the dibasic acid (dicarboxylic acid) component represented by A, an aliphatic dibasic acid and an alicyclic dibasic acid are preferable, and examples of the aliphatic dibasic acid include malonic acid, succinic acid, glutaric acid, adipic acid Aliphatic dicarboxylic acids having 4 to 12 carbon atoms and at least one selected from the group consisting of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, alicyclic dicarboxylic acids, Can be used. That is, two or more kinds of dibasic acids may be used in combination.

m and n represent the number of repeating units, preferably 1 or more and 170 or less.

(The polyester represented by the formula (f) or (g)

The base layer may include a polyester represented by the following formula (f) or (g).

(Wherein B1 represents a monocarboxylic acid having 1 to 12 carbon atoms, G represents a divalent alcohol having 2 to 12 carbon atoms, and A represents a dibasic acid having 2 to 12 carbon atoms. All do not include aromatic rings, and m represents the number of repeats)

(Wherein B 2 represents a monohydric alcohol having 1 to 12 carbon atoms, G represents a divalent alcohol having 2 to 12 carbon atoms, and A represents a dibasic acid having 2 to 12 carbon atoms. N is the number of repeats)

In the formulas (f) and (g), B1 represents a monocarboxylic acid component, B2 represents a monohydric alcohol component, G represents a divalent alcohol component having 2 to 12 carbon atoms, Dibasic acid component, and is synthesized therefrom. B1, G and A do not all contain an aromatic ring. m and n represent the number of repeats. B1 and B2 are synonymous with B1 and B2 in the above-described formula (d) or (e). G and A correspond to an alcohol component or a dibasic acid component having 2 to 12 carbon atoms in G and A in the above-mentioned formula (d) or (e).

The number average molecular weight of the polyester is 1000 to 10000. If the number-average molecular weight is less than 1,000, breakage tends to occur at high temperature and high-rate stretching. If the number average molecular weight is more than 10,000, whitening due to phase separation tends to increase.

The polycondensation of the polyester is carried out by a conventional method. For example, a direct reaction between the dibasic acid and a glycol, a dibasic acid or an alkyl ester thereof, for example, a polyester esterification reaction or ester exchange reaction between a methyl ester of a dibasic acid and a glycol, The polyester can be easily synthesized by a melt condensation method or a dehydrohalogenation reaction of an acid chloride and a glycol of these acids, but the polyester having a weight average molecular weight not so large is preferably synthesized by a direct reaction Do.

Some polyesters having a high distribution on the low molecular weight side have a very good compatibility with cellulose acylate and have a low moisture permeability and transparency after film formation, and thus can obtain a cellulose acylate film. The method for controlling the molecular weight may be a conventional method without any particular limitation. For example, in the case of using a monovalent acid or a monohydric alcohol to block the molecular terminal, the molecular weight can be controlled by adjusting the amount of the monovalent starting compound to be added. In this case, it is preferable to adjust the monovalent acid addition amount from the viewpoint of the stability of the polymer. For example, acetic acid, propionic acid, butyric acid and the like can be mentioned. It is preferable to select those which are not easily distilled out from the system during the polycondensation reaction but are easily distilled off when they are removed from the reaction system. Further, a plurality of compounds may be mixed for this purpose. In the case of the direct reaction, the weight average molecular weight can be controlled by measuring the timing at which the reaction is stopped by the amount of water produced during the reaction. In addition, the molecular weight can be controlled by adjusting the molar amount of the introduced glycol or dibasic acid, and the molecular weight can be controlled by controlling the reaction temperature.

The polyester is preferably contained in an amount of 0.1 to 30 mass%, more preferably 2 to 20 mass%, based on 100 mass% of the whole base layer.

<Ultraviolet absorber>

The base layer may contain an ultraviolet absorber. The ultraviolet absorbent is intended to improve durability by absorbing ultraviolet rays of 400 nm or less, and particularly preferably has a transmittance at a wavelength of 370 nm of 10% or less, more preferably 5% or less, further preferably 2% to be. When the substrate layer contains an ultraviolet absorber, it is preferable that two or more ultraviolet absorbers are included.

The ultraviolet absorber to be used in the present invention is not particularly limited, and examples thereof include oxybenzophenone compounds, benzotriazole compounds, salicylic ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, Based compounds, inorganic powders, and the like.

Benzotriazole, (2-2H-benzotriazol-2-yl) -6- (3,5-di-sec- (Straight chain and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone and the like, and also Tinuvin 109, Tinuvin 171, Tinuvin 234 , Tinuvin 326, Tinuvin 327 and Tinuvin 328, all of which are commercially available from BASF Japan Co., Ltd. and can be preferably used.

The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber. In addition, a discotic compound such as a compound having 1,3,5-triazine ring is also preferably used as an ultraviolet absorber. As the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used. In particular, a polymer-type ultraviolet absorber described in JP-A-6-148430 is preferably used.

The ultraviolet absorber may be added by dissolving an ultraviolet absorber in an alcohol such as methanol, ethanol, butanol, or an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof, . In the case of not dissolving in an organic solvent such as an inorganic powder, it may be dispersed in an organic solvent and a cellulose ester resin using a dissolver or a sand mill and then added to the dope.

The ultraviolet absorber is preferably contained in an amount of 0.1 to 15 mass%, more preferably 1 to 10 mass%, based on 100 mass% of the total amount of the substrate layer.

<Infrared absorbent>

The substrate layer may contain an infrared absorbing agent. With such a constitution, the reverse wavelength dispersion property of the film can be adjusted.

The infrared absorbing agent preferably has a maximum absorption in a wavelength range of 750 to 1100 nm, and more preferably a maximum absorption in a wavelength range of 800 to 1000 nm. Further, the infrared absorbent preferably has substantially no absorption in the visible region.

As the infrared absorbing agent, it is preferable to use an infrared absorbing dye or an infrared absorbing pigment, and it is particularly preferable to use an infrared absorbing dye.

The infrared absorbing dye includes an organic compound and an inorganic compound. It is preferable to use an infrared absorbing dye which is an organic compound. Organic infrared absorbing dyes include cyanine compounds, metal chelate compounds, aminium compounds, diimonium compounds, quinone compounds, squarylium compounds and methine compounds. For infrared absorbing dyes, see Coloring materials, 61 [4] 215-226 (1988) and Chemical Industry, 43-53 (1986, May).

Considering the kinds of dyes in terms of infrared absorption function or absorption spectrum, infrared absorbing dyes developed in the technical field of silver halide photographic light-sensitive materials are excellent. Infrared absorbing dyes developed in the field of silver halide photographic light-sensitive materials include dihydroperimidine squarylium dyes (US Patent No. 5380635 and Japanese Patent Application No. 8-189817), cyanine dyes (Japanese Patent Laid- JP-B-62-123454, JP-B-3-138640, JP-B-3-211542, JP-A-3-226736, JP-A-5-313305, JP-A-6-43583, JP-A 7-269097, (Japanese Patent Application Laid-Open Nos. 3-131640 and 3-211542), diimonium dyes (Japanese Patent Application Laid-Open Nos. 3-138640 and 3-211542) (Japanese Patent Application Laid-open No. Hei 2-282244), indian aniline dyes (Japanese Patent Application Laid-open Nos. 5-323500 and 5-323501), polymethine dyes 3-26765, 4-190343 and European Patent No. 377961), oxonol salts (Japanese Patent Application Laid-Open No. 3-9346), anthraquinone dyes (Japanese Patent Application Laid-Open No. 4-13654), naphthalocyanine dyes (US Patent No. 5009989), and naphtholactam dyes No. 568267). These infrared absorbers may be used alone, or two or more of them may be used in combination.

The infrared absorbing agent is preferably contained in an amount of 0.1 to 30 mass%, more preferably 2 to 20 mass%, based on 100 mass% of the total amount of the substrate layer.

&Lt; Matting agent (fine particles) >

In order to improve the handling property, the base layer is provided with a base layer made of at least one of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, Of inorganic fine particles or crosslinked polymers as a matting agent. Among them, silicon dioxide is preferable because the haze of the film can be reduced.

The average primary particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

The fine particles are preferably contained in the film by forming secondary particles at a particle diameter of 0.1 to 5 占 퐉, and the average particle diameter is preferably 0.1 to 2 占 퐉, more preferably 0.2 to 0.6 占 퐉. Thereby, irregularities having a height of about 0.1 to 1.0 mu m are formed on the surface of the film, whereby appropriate sliding property can be given to the film surface.

The average primary particle diameter of the fine particles used in the present invention was measured by observing the particles with a transmission electron microscope (magnification: 500,000 to 2,000,000 times), observing 100 particles, measuring the particle diameter, , And the average primary particle diameter.

The apparent specific gravity of the fine particles is preferably 70 g / liter or more, more preferably 90 to 200 g / liter, and particularly preferably 100 to 200 g / liter. The larger the apparent specific gravity is, the more preferable is the preparation of a high-concentration dispersion, the haze and agglomerates are preferred, and the dope having a high solid concentration is particularly preferably used.

The silicon dioxide fine particles having an average primary particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more can be obtained, for example, by combustion of airborne silicon tetrachloride mixed with hydrogen at 1000 to 1200 占 폚 in air. For example, they are commercially available under the trade names Aerosil R812, Aerosil 200V and Aerosil R972V (manufactured by Nihon Aerosil Co., Ltd.), and they can be used.

The apparent specific gravity described above is obtained by employing a silicon dioxide fine particle in a certain amount of a measuring cylinder and measuring the weight at that time.

Apparent Specific Gravity (g / liter) = mass of silicon dioxide (g) / volume of silicon dioxide (liters)

The matting agent (fine particles) is preferably contained in an amount of 0.01 to 5 mass%, more preferably 0.1 to 3 mass%, based on 100 mass% of the entire base layer.

<Colorant>

The substrate layer may contain a coloring agent. The term &quot; colorant &quot; means a dye or a pigment. In the present invention, it is particularly preferable to have an effect of making the color tone of the liquid crystal screen blue, or adjusting the yellow index and reducing the haze. As the colorant, various dyes and pigments can be used, and in particular, anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.

The colorant is preferably contained in an amount of 0.01 to 5 mass%, more preferably 0.1 to 3 mass%, based on 100 mass% of the whole base layer.

As the preferred embodiment, the base layer includes the cellulose ester resin. In the polarizing plate according to this embodiment, the base layer is preferably a so-called &quot; zero-phase difference film &quot;. Since the substrate layer serving as the polarizing plate protective film is a zero-retardation film, there is an advantage that no phase difference is produced even when a high magnification drawing process is performed, and rainbow stains and the like are not generated when the image display device is incorporated. When this is quantitatively expressed, the base layer can be obtained by the following formulas (5) and (6):

(Where nx represents the refractive index in the slow axis direction in the film plane, ny represents the refractive index in the fast axis direction in the film plane, nz represents the refractive index in the film thickness direction, and d represents the thickness ; The refractive index was measured at a wavelength of 590 nm under an environment of 23 캜, 55% RH)

For each of Ro and Rth,

Is satisfied. Ro is more preferably -4 to 4, and particularly preferably -3 to 3. Further, Rth is more preferably -4 to 4, and particularly preferably -3 to 3. Further, in order to control the Ro and Rth to values within the above-mentioned range, the composition of the film, the stretching condition, the kind and addition amount of the retardation adjusting agent, and the like may be appropriately adjusted at the time of production of the base layer.

It is preferable that the hydrophilic polymer layer and the substrate layer are adhered to each other with an adhesive. The specific constitution of the adhesive is not particularly limited, and any adhesive can be used as long as it does not impair the action and effect of the present invention. As an example of the adhesive, there can be mentioned a polyvinyl alcohol aqueous solution (so-called watercolor).

Further, a photo-curable adhesive may be used as the adhesive. The photo-curable adhesive preferably contains an epoxy compound and a cationic polymerization initiator.

The specific constitution of the epoxy compound and the cationic polymerization initiator contained in such a photo-curable adhesive and the blending amount of each component are not particularly limited, but from the viewpoint of adhesiveness, the epoxy compound is a polyvalent epoxy compound (an epoxy compound having at least two epoxy groups in the molecule ). The polyvalent epoxy compound includes an aromatic polyvalent epoxy compound having at least two epoxy groups and aromatic rings in the molecule and an alicyclic polyvalent epoxy compound having at least two epoxy groups in the molecule and at least one of which is bonded to an alicyclic ring, An aliphatic polyvalent epoxy compound having no aromatic ring and having one carbon atom bonded to another aliphatic carbon atom of a ring (usually an oxirane ring) containing two carbon atoms to which an epoxy group is bonded, and the like. Examples of such a polyvalent epoxy compound include those represented by any one of the following formulas (A) to (D).

(Wherein R ¹ to R ³ each independently represents an alkyl group or a halogen atom, L ¹ and L ² each independently represent a divalent aliphatic organic group, M represents an oxygen atom or a nitrogen atom, A A and b each independently represent an integer of 0 to 4, x and y each independently represent a real number of 0 to 20, 1 represents 1 or 2, and m Represents an integer of 2 to 4)

In the formulas (A), (B) and (D), examples of L ¹ and L ² include, for example,

, And the like in the formula (C)

And the like.

The alkyl group of R ¹ , R ² and R ³ preferably has 1 to 3 carbon atoms, and examples of the halogen atom include Br, Cl, F and the like.

Specific examples of the polyvalent epoxy compound represented by the formula (A), (B), (C) or (D) are shown below, but the present invention is not limited thereto.

In the compound (IV-1), n is an integer of 0 to 20.

In addition, the variables x and y in the equation are real numbers and may be any values in the range of 0 to 20, respectively. The reason why x and y do not necessarily have to be integers is that epoxy compounds having several kinds of integer values are in a mixed state at a certain ratio and show an average value thereof. These polyvalent epoxy compounds may be used alone or in combination of two or more.

Other examples of the polyvalent epoxy compound include those represented by any one of the following formulas (E) to (O).

(Wherein R ⁴ to R ²⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and when R ⁴ to R ²⁵ are alkyl groups, the position bonded to the alicyclic ring is 1 to 6 Y ⁸ represents an oxygen atom or an alkanediyl group having 1 to 20 carbon atoms, and the alkyl group having 1 to 20 carbon atoms may be a straight-chain, branched or alicyclic ring, Y ¹ to Y ⁷ each independently represent an alkanediyl group having 1 to 20 carbon atoms, which may be linear, branched, or may have an alicyclic ring, and n, p, q and r Each independently represent a real number of 0 to 20)

Of these, alicyclic diepoxy compounds represented by the formula (f) are preferred because they are readily available. The alicyclic diepoxy compound of the formula (f) can be obtained by reacting 3,4-epoxycyclohexylmethanol (the cyclohexane ring may have an alkyl group having 1 to 6 carbon atoms) and 3,4-epoxycyclohexanecarboxylic acid (The cyclohexane ring may have an alkyl group of 1 to 6 carbon atoms bonded thereto). Specific examples thereof include the following compounds.

3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (compound of formula (f) wherein R ⁶ = R ⁷ = H, n = 0)

6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate (In the formula (f), R ⁶ = 6-methyl, R ⁷ = 0).

The polyvalent epoxy compound and the oxetane compound (to be described later) to be added as needed are cured by cationic polymerization. Therefore, it is preferable that a photo cationic polymerization initiator is blended in the photo-curable adhesive. This photo cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation of an active energy ray such as visible light, ultraviolet ray, X-ray or electron ray to initiate polymerization reaction of the epoxy group.

By incorporating such a cationic photopolymerization initiator, it becomes possible to cure at room temperature, the heat resistance of the polarizer, and the need to take into account distortion caused by expansion or contraction are reduced, and the cellulose acylate film can be favorably adhered. Further, since the cationic photopolymerization initiator acts catalytically upon irradiation of an active energy ray, it is excellent in storage stability and workability even when it is mixed with an epoxy compound or an oxetane compound described later. Examples of the compound capable of generating a cationic species or Lewis acid upon irradiation with an active energy ray include an onium salt such as an aromatic diazonium salt, an aromatic iodonium salt and an aromatic sulfonium salt, and an iron-allene complex.

As the aromatic diazonium salt, for example, the following compounds can be mentioned.

Benzene diazonium hexafluoroantimonate, benzene diazonium hexafluoroantimonate,

Benzene diazonium hexafluorophosphate,

Benzene diazonium hexafluoroborate and the like.

As the aromatic iodonium salt, for example, the following compounds can be mentioned.

Diphenyl iodonium tetrakis (pentafluorophenyl) borate,

Diphenyl iodonium hexafluorophosphate,

Diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate,

Di (4-nonylphenyl) iodonium hexafluorophosphate, and the like.

As the aromatic sulfonium salt, for example, the following compounds can be mentioned.

Triphenylsulfonium hexafluorophosphate,

Triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroantimonate,

Triphenylsulfonium tetrakis (pentafluorophenyl) borate,

Diphenyl (4- (phenylthio) phenyl) sulfonium hexafluorophosphate,

Diphenyl (4- (phenylthio) phenyl) sulfonium hexafluoroantimonate,

4,4'-bis (diphenylsulfono) diphenylsulfide bis hexafluorophosphate,

4,4'-bis (di (? - hydroxyethoxy) phenylsulfonyl) diphenyl sulfide bis hexafluoroantimonate,

4,4'-bis (di (beta -hydroxyethoxy) phenylsulfonio) diphenylsulfide bis hexafluorophosphate,

7- (di (p-toluyl) sulfonio) -2-isopropylthioxanthone hexafluoroantimonate,

7- (di (p-toluyl) sulfonio) -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,

4-phenylcarbonyl-4'-diphenylsulfone-diphenylsulfide hexafluorophosphate,

4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate,

4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate and the like.

As the iron-allene complex, for example, the following compounds can be mentioned.

Xylene-cyclopentadienyl iron (II) hexafluoroantimonate,

Cumene-cyclopentadienyl iron (II) hexafluorophosphate,

Xylene-cyclopentadienyl iron (II) -tris (trifluoromethylsulfonyl) methanide, and the like.

Each of these photo cationic polymerization initiators may be used alone or in combination of two or more. Among them, an aromatic sulfonium salt is preferably used since it has an ultraviolet ray absorption property in a wavelength region of 300 nm or more, and is excellent in curability and can give a cured product having good mechanical strength and adhesive strength.

The cationic cationic polymerization initiator may be commercially available, for example, "Kayalard PCI-220", "Kayalard PCI-620" (manufactured by Nippon Kayaku Co., Ltd.) "ADEKA OPTOMER SP-150", "ADEKA OPTOMER SP-170" (manufactured by ADEKA), "CI-5102" (manufactured by Dow Chemical Co.) DPI-101 "," DPI-2064S ", and" CIP-2064S "(all of which are manufactured by Nippon Soda Co., Ltd.) 102, "" DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI- , "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS-102" , Irgacure PAG103, Irgacure PAG108, Irgacure PAG121, Irgacure PAG203, Irgacure PAG203, Irgacure PAG203, CPI-200P "," CPI-210S "(available from Sanyo-Afro Co., Ltd.), and the like, Diphenyl (4- (phenylthio) phenyl) sulfo UVI-6992 "manufactured by Dow Chemical Co., Ltd.," CPI-100P "," CPI-101A "," CPI-200K ", and" CPI-210S " desirable.

The mixing ratio of the photo cationic polymerization initiator is preferably in the range of 0.5 to 20% by mass based on the total photo-curable adhesive. If the ratio is 0.5% by mass or more, the curing of the adhesive is sufficiently achieved, and mechanical strength and adhesive strength are secured. On the other hand, if the ratio is 20 mass% or less, the hygroscopic property of the cured product accompanied by the increase of the ionic substance in the cured product and the deterioration of the durability performance due to the increase of the hygroscopic property are suppressed.

The photo-curable adhesive may further contain an oxetane compound or an unsaturated compound, if necessary, in addition to the above-described components. When the photo-curing adhesive contains an unsaturated compound, it is preferable to further include a photo radical polymerization initiator. Examples of other components include a photosensitizer, a thermal cationic polymerization initiator, a polyol, a silane coupling agent, an ion trap agent, an antioxidant, a light stabilizer, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, , Antifoaming agents, leveling agents, coloring matters, and organic solvents.

As described above, in the stretched laminate in which the hydrophilic polymer layer and the base layer are laminated and stretched, the hydrophilic polymer layer functions as a polarizer, and the base layer functions as a polarizer protective film. Thereby, the stretched laminate can be used as a polarizing plate. Here, a conventionally known polarizing plate protective film may be further bonded to the surface of the hydrophilic polymer layer serving as a polarizer opposite to the substrate layer. As such a polarizing plate protective film, a commercially available cellulose ester film can be used. As the commercially available cellulose ester film, for example, Konica Minolta Tact KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UA, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC8UX-RHA, KC8UXW- RHA-NC, and KC4UXW-RHA-NC (manufactured by Konica Minolta Advantages Co., Ltd.) are preferably used. Alternatively, it is also preferable to further use a polarizing plate protective film serving also as an optical compensation film having an optically anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystals, rod-shaped liquid crystals and cholesteric liquid crystals. For example, an optically anisotropic layer can be formed by the method described in Japanese Patent Application Laid-Open No. 2003-98348. By using in combination with the polarizing plate according to the present invention, it is possible to obtain a polarizing plate excellent in planarity and having a stable viewing angle increasing effect. It is also possible to improve the quality of the polarizing plate protective film located on the side farther from the liquid crystal cell or on the film, and to arrange a film having other functions. For example, anti-reflection (anti-reflection), anti-glare (AG), scratches (hard coating HC), low reflection (low reflection (LR) A film containing a known functional layer as a display as a display for antistatic, antifouling, backcount can be used as the polarizer protective film. Alternatively, a film containing these functional layers may be separately attached to the surface of a polarizing plate protective film such as a general-purpose TAC film.

The polarizing plate having the above-described structure can also be constituted by bonding a protective film to one side and a separate film to the opposite side. The protective film and the separate film are used for the purpose of protecting the polarizing plate when the polarizing plate is shipped, when the product is inspected. In this case, the protective film is bonded to protect the surface of the polarizing plate, and is used on the opposite surface side of the polarizing plate bonded to the display panel. Further, the separate film is used for covering the adhesive layer to be bonded to the panel, and is used on the side of bonding the polarizing plate to the liquid crystal cell.

In the polarizing plate according to the present invention, the film thickness of the oriented laminate (a layered product of the above-described hydrophilic polymer layer and base layer and stretched state) is preferably 10 to 100 占 퐉, more preferably 20 To 95 탆, and more preferably from 30 to 90 탆. When the film thickness of the drawn laminate is 10 탆 or more, the reworkability at the time of panel joining is sufficient. On the other hand, when the stretched laminate has a thickness of 100 탆 or less, the curl of the polarizing plate can be suppressed, the thickness of the member can be reduced, and the weight can be reduced.

Further, the polarizing plate according to the present invention is characterized in that variations in the behavior of curl under different circumstances are small. Specifically, in the polarizing plate according to the present invention, the difference ΔC = | C ₁ -C ₂ | between curl C ₁ under a 23 ° C. 55% RH environment and curl C ₂ under a 40 ° C. and 20% RH environment satisfies ΔC 80 [ 1 / m]. Here,? C preferably satisfies? C? 60, more preferably satisfies? C? 50, and more preferably satisfies? C? 40. As described above, in the present invention, by taking the properties of the coating type polarizing plate into account, and by making the configuration of the coating type polarizing plate less fluctuation in the curl behavior under different circumstances, it is possible to prevent occurrence of color unevenness And a polarizing plate capable of suppressing the light emitted from the polarizing plate. As the values of C ₁ and C ₂ and ΔC, the values measured by the method described in the column of the following examples will be adopted. In order to control these values, it is necessary to adjust the elastic modulus of the first base layer and the elastic modulus of the second base layer at the time of manufacturing the polarizing plate, thereby appropriately adjusting the stretching conditions of the thermoplastic resin, It is possible to carry out operations such as controlling to an appropriate thickness and selecting a suitable thermoplastic resin species.

&Lt; Polarizing plate production method &gt;

The method for producing the polarizing plate (stretched laminated product) according to the present invention is not particularly limited, and can be suitably produced while referring to conventionally known knowledge and the column of Examples described later. An example of a method for producing a polarizing plate (stretched laminate) can be obtained by, for example, applying an aqueous solution containing a hydrophilic polymer to a substrate layer and then drying to form a laminate. By such application, the base layer and the hydrophilic polymer layer are laminated directly or, preferably, through the layer of the photo-curable adhesive to obtain a laminate in which the base layer and the hydrophilic polymer layer are integrated.

There is no particular limitation on the method for producing the substrate layer, and conventionally known knowledge regarding a method for producing a film including a cellulose ester resin may be appropriately referred to. It is preferable to form the base layer by a solution casting method using a previously prepared dope liquid. If possible, the base layer may be formed by the melt-softening method.

The base layer may be a layer that has been subjected to stretching treatment before coating the aqueous solution containing the hydrophilic polymer. The stretching treatment may be uniaxial stretching, biaxial stretching, tilting stretching, or the like. The uniaxial stretching may be vertical stretching performed in the longitudinal direction of the substrate layer or transverse stretching performed in the width direction of the base layer. In the transverse direction stretching, the stretching in the width direction and the stretching in the longitudinal direction may be performed. Examples of the transverse stretching method include a fixed single uniaxial stretching method in which one end is fixed through a tenter, a free end uniaxial stretching method in which one end is not fixed, and the like. Examples of the longitudinal stretching method include a roll-to-roll stretching method, a compression stretching method, and a stretching method using a tenter. The stretching process may be performed in multiple stages. When the stretching treatment for the substrate layer is uniaxial stretching, longitudinal stretching (stretching in the MD direction) is preferable.

There is no particular limitation on the temperature at the time of drawing treatment of the base layer, but it is preferably 130 to 200 占 폚, and more preferably 150 to 180 占 폚. In the stretching treatment of the base layer, the base layer may be stretched in the range of 1.1 to 10 times the total stretching ratio in all directions with respect to the original length of the base layer. Preferably 2 to 6 times, and more preferably 3 to 5 times.

When the base layer is formed of a laminate of two or more layers, such a base layer can be produced by a conventionally known method for producing a resin laminate. For example, as described in the column of Examples to be described later, two kinds of dope liquids having different compositions are prepared, a film is prepared by the solution casting method using one side, and the film is dried, By making the liquid more flexible and drying, a base layer in which two base layers are laminated can be produced. If necessary, the first layer film may be subjected to stretching treatment alone or in a base layer having a laminated structure.

The aqueous solution containing the hydrophilic polymer can be produced by dissolving a powder of a hydrophilic polymer or a pulverized product or a cut product of a hydrophilic polymer film in appropriately heated water (hot water). The application of the aqueous solution onto the substrate layer may be carried out by a roll coating method such as a wire bar coating method, a reverse coating method or a gravure coating method, a spin coating method, a screen coating method, a fountain coating method, a dipping method, Can be appropriately selected and adopted. When the base layer has a layer of a photo-curable adhesive, the aqueous solution is directly applied to the base layer when the base layer does not have the layer. The drying temperature is usually 50 to 200 占 폚, preferably 80 to 150 占 폚, and the drying time is usually about 5 to 30 minutes.

The laminate used in the present invention can also be formed by coextrusion of a forming material of a base layer and a forming material of a hydrophilic polymer layer. A laminate in a state in which the base layer and the hydrophilic polymer layer are integrated by co-extrusion may be obtained. In co-extrusion, it is preferable to inject the material of the substrate layer and the material of the hydrophilic polymer layer into the co-extruder as the forming material of each layer, and to control the thickness of the coextruded base layer and the hydrophilic polymer layer to be in a desired range Do.

Subsequently, the laminate before stretching obtained above is subjected to a stretching treatment and a dyeing treatment with a dichroic material. In the stretched laminate subjected to each treatment, the dichromatic material is adsorbed on the obtained hydrophilic polymer layer by the stretching treatment to the hydrophilic polymer layer and the dyeing treatment with the dichroic substance, and functions as a polarizer.

The stretching treatment is carried out by performing uniaxial stretching, biaxial stretching, or tilt stretching on the laminate obtained above. This stretching process may be performed in multiple stages. When the base layer is not drawn in advance and the laminate is uniaxially stretched, it is preferable that the uniaxial stretching is vertical stretching (stretching in the MD direction). On the other hand, in the case where the base layer is previously stretched in the longitudinal direction (stretching in the MD direction) and the stretching treatment of the laminate is uniaxial stretching, it is preferable that the above monoaxial stretching is transverse stretching (stretching in the TD direction) Do.

There is no particular limitation on the temperature at the time of drawing treatment of the laminate, but it is preferably 130 to 200 占 폚, and more preferably 150 to 180 占 폚. In the stretching treatment of the laminate, the total stretching ratio in all directions with respect to the original length of the laminate may be set to be in the range of 2 to 10 times. Preferably 3 to 8 times, and more preferably 3 to 7 times.

The dyeing treatment is carried out by adsorbing a dichroic substance to the hydrophilic polymer layer of the laminate. Since the dichroism material has been described above, the description thereof is omitted here. The dyeing treatment is carried out, for example, by immersing the layered product in a solution (dyeing solution) containing a dichroic substance. As the dyeing solution, a solution in which a dichromatic substance is dissolved in a solvent can be used. As the solvent, water is generally used, but an organic solvent compatible with water may be further added. The concentration of the dichroic substance in the dyeing solution is preferably in the range of 0.01 to 10 mass%, more preferably 0.02 to 7 mass%, and particularly preferably 0.025 to 5 mass%.

Further, in the case of using iodine as the dichroic substance, it is preferable to add iodide because the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. The addition ratio of these iodides is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass in the dyeing solution. Among them, it is preferable to add potassium iodide, and the ratio (mass ratio) of iodine to potassium iodide is preferably in the range of 1: 5 to 1: 100, more preferably in the range of 1: 6 to 1:80 , And particularly preferably in the range of 1: 7 to 1: 70.

The immersing time of the laminate in the dyeing solution is not particularly limited, but is usually in the range of 15 seconds to 5 minutes, more preferably 1 to 3 minutes. The temperature of the dyeing solution is preferably in the range of 10 to 60 占 폚, and more preferably in the range of 20 to 40 占 폚. In the dyeing treatment, the dichromatic material is adsorbed on the hydrophilic polymer layer of the laminate to orient the dichroic material. The dyeing treatment can be carried out before, simultaneously with, or after the stretching treatment of the laminate, but the dyeing treatment is preferably carried out after the stretching treatment is applied to the laminate in that the dichroic substance adsorbed on the hydrophilic polymer layer is favorably oriented desirable.

«Display device»

The polarizing plate according to the present invention can be used in various display devices such as a liquid crystal display device and an organic electroluminescence (EL) display device.

For example, by incorporating the polarizing plate according to the present invention in a liquid crystal display, a liquid crystal display having excellent visibility can be manufactured. In addition, since the polarizer according to the present invention is also excellent in the workability, the productivity of the display device can be greatly improved. The polarizing plate of the present invention can be used in liquid crystal display devices of various driving systems such as STN, TN, OCB, HAN, VA (MVA, PVA), and IPS. Preferably a VA (MVA, PVA) type and an IPS type liquid crystal display device. Particularly, it is preferable to be built in an IPS mode liquid crystal display device.

The liquid crystal layer of the liquid crystal panel in the IPS mode liquid crystal display device is a homogeneous alignment in parallel with the substrate surface in the initial state and the director of the liquid crystal layer in a plane parallel to the substrate is parallel to the electrode wiring direction The direction of the director of the liquid crystal layer shifts in the direction perpendicular to the electrode wiring direction with the application of the voltage and the direction of the director of the liquid crystal layer is shifted in the direction of the director when the voltage is not applied When the liquid crystal layer is inclined in the direction of the 45 DEG electrode wiring, the azimuth angle of the polarized light is rotated by 90 DEG as in the case of the 1/2 wave plate and the azimuth angle of the polarized light coincides with the transmission axis of the emission- Display.

Generally, the thickness of the liquid crystal layer is constant, but it is possible to increase the response speed to switching by forming the unevenness slightly in the thickness of the liquid crystal layer because it is a transverse electric field drive. However, The effect can be maximized and the influence of the change in the thickness of the liquid crystal layer is small. The thickness of the liquid crystal layer is 2 to 6 占 퐉, preferably 3 to 5.5 占 퐉. The liquid crystal display device according to this embodiment can be preferably used for portable devices such as tablet-type display devices and smart phones, in addition to those used for a large-sized liquid crystal TV.

The details of the IPS mode liquid crystal cell are not particularly limited, and the present invention may be practiced by referring to other conventionally known technical matters (for example, Japanese Laid-Open Patent Publication No. 2010-3060).

Example

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

&Lt; Preparation of polyvinyl alcohol aqueous solution >

A polyvinyl alcohol film (average polymerization degree: 2400, saponification degree: 99 mol%, trade name: VF-PS2400) manufactured by Kuraray Co., Ltd., which is a film containing hydrophilic polymer, was cut into small pieces each having a side length of 5 mm or less, To prepare a polyvinyl alcohol aqueous solution having a concentration of 10% by mass.

<Production of polarizing plate>

(Production of optical film F1)

(Preparation of Dope Liquid a)

30 parts by mass of diacetylcellulose (L50, manufactured by Daicel)

Methylene chloride 227 parts by mass

Ethanol 43 parts by mass

The above materials were placed in a pressure-tightly sealed container, heated at 80 DEG C, and the resin component was completely dissolved while stirring at 2 atmospheric pressure to obtain a dope. (Manufactured by Asahi Glass Co., Ltd.). 244, and the dope was lowered to 35 DEG C and allowed to stand overnight to carry out defoaming in the dope.

(Preparation of Dope Liquid b)

70 parts by mass of Dianal BR-85 (acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.)

CAP482-20 (cellulose acetate propionate, manufactured by Eastman Chemical Company, acetyl substitution degree 0.18, propionyl substitution degree 2.60) 30 parts by weight

Methylene chloride 252 parts by mass

48 parts by mass of ethanol

The above materials were placed in a pressure-tightly sealed container, heated at 80 DEG C, and the resin component was completely dissolved while stirring at 2 atmospheric pressure to obtain a dope. (Manufactured by Asahi Glass Co., Ltd.). 244, and the dope was lowered to 35 DEG C and allowed to stand overnight to carry out defoaming in the dope.

(Preparation of base layer by solution casting method)

The dope liquid b prepared above was uniformly plied to a 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 amount of the residual solvent became 100%, and peeled off on the stainless steel band support with a peel tension of 162 N / m.

The peeled web was evaporated at 35 占 폚, slit to 1.6m width, and then dried at a drying temperature of 135 占 폚 while being stretched 1.1 times in the width direction in the tenter.

At that time, the amount of the residual solvent when the stretching was started in the tenter was 10%. After the stretching in the tenter, the film was relaxed at 130 DEG C for 5 minutes. Then, the drying zone was transferred to a plurality of rolls at 120 DEG C and 130 DEG C while being slit with a width of 1.5 m. And was wound up on an inner diameter 6-inch core at an initial tension of 220 N / m and a final tension of 110 N / m to obtain an optical film.

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 residual solvent amount was 0.1%, the film thickness was 60 μm, and the number of windings was 4000 m.

Subsequently, the wound film was loosened, and the dope liquid a prepared above was plied on the unwound film and dried at 50 DEG C until the amount of the residual solvent in the resin layer containing the dope liquid a became 100% , And then dried stepwise at 120 캜 and 130 캜. Drying was carried out until the amount of the residual solvent became 0.3% in total of the film, and thereafter, the film was wound up to obtain an optical film F1. The thickness of the resin layer including the dope liquid a was 15 占 퐉.

(Production of polarizing plate PL1)

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the optical film F1 obtained above and then dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m, .

(Drawing process)

The laminate thus obtained was stretched at 145 deg. C in a longitudinal direction (MD direction) with a roll roll at a draw ratio of 6, to obtain a drawn laminate.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL1. Further, the thickness of the base layer F1 (after stretching) in the obtained PL1 was 30 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL1 was 2 占 퐉.

(Production of optical film F2)

<Fine Particle Dispersion 1>

Fine particles (Aerosil R812, manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass

Ethanol 89 parts by mass

The mixture was stirred for 50 minutes in a dissolver, and then dispersed with Manton-Gaulin.

&Lt; Fine Particle Addition Solution 1 >

The fine particle dispersion 1 was slowly added while sufficiently stirring in a dissolution tank containing methylene chloride. In addition, the particles were dispersed in the attritor so that the particle size of the secondary particles became a predetermined size. This was filtrated with FineMet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle addition liquid 1.

99 parts by mass of methylene chloride

Fine particle dispersion 15 parts by mass

To prepare a main dope solution having the following composition. First, methylene chloride and ethanol were added to the pressure-dissolving tank. A pressurized dissolution tank containing a solvent was charged with 2.30 g of cellulose acetate having an acetyl substitution degree with stirring. This was heated and completely dissolved while stirring. Azumi Co., Ltd., made by Azumi Co., Ltd. 244, to prepare a main dope solution.

<Composition of main doping solution>

The following two types of dope were prepared, and the optical film F2, which is a constitution of the skin layer / core layer / skin layer, was all produced by the softening.

(Preparation of Cellulose Acylate Dope for Core Layer)

Cellulose acetate (acetyl substitution degree: 2.30) 100 parts by mass

Triphenylphosphate / biphenyldiphenylphosphate copolymer (copolymer ratio: 1: 1) 10 parts by mass

Dichloromethane 406 parts by mass

Methanol 61 parts by mass

(Preparation of cellulose acylate dope for skin layer)

Cellulose acetate (acetyl substitution degree 2.80) 100 parts by mass

Triphenylphosphate / biphenyldiphenylphosphate copolymer (copolymer ratio: 1: 1) 13 parts by mass

Particulate matter added liquid 12 parts by mass

Dichloromethane 406 parts by mass

Methanol 61 parts by mass

Each of the above compositions was put into a mixing tank and stirred to dissolve each component, followed by filtration through a filter paper having an average pore diameter of 34 탆 and a sintered metal filter having an average pore diameter of 10 탆 to prepare each cellulose acylate dope. The dope was shared with a three-layer structure consisting of a skin layer, a core layer and a skin layer with a band softener. Here, by adjusting the amount of softening of each dope, the core layer was made thickest, and as a result, simultaneous multilayer softening was performed so that the film thickness after stretching was 15 탆 for the core layer, 10 탆 for the skin layer, and 35 탆 for the sake. The film peeled off from the band at a residual solvent amount of about 30 mass% was hot air heated at 160 캜 by a tenter to widen the film to a draw ratio of 1.32 and then relaxed at 140 캜 for 60 seconds so that the draw ratio was 1.3 times. Thereafter, the process was shifted from the tenter conveyance to the roll conveyance, and was further dried at 120 ° C to 150 ° C and wound.

(Production of polarizing plate PL2)

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the obtained optical film F2 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m to obtain a laminate .

(Drawing process)

The laminate thus obtained was stretched at 150 DEG C in a longitudinal direction (MD direction) at a draw ratio of 2 by a roll roll to obtain a stretched laminate.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL2. The thickness of the obtained base layer (F2 (after stretching) in PL2 was 25 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL2 was 3 占 퐉.

(Production of optical film F3)

An optical film F3 (thickness: 55 mu m) was produced by the method described in Example 1 of JP-A-2010-30225.

(Production of polarizing plate PL3)

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the resulting optical film F3 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m to obtain a laminate .

(Drawing process)

The laminate thus obtained was stretched at 150 DEG C in a longitudinal direction (MD direction) at a draw ratio of 2 by a roll roll to obtain a stretched laminate.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL3. Further, the thickness of the obtained base layer (after stretching) of PL3 was 40 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL3 was 3 占 퐉.

(Production of optical film F4)

A laminate optical film F4 (thickness: 135 mu m) was obtained by the method described in Example 1 of JP-A-2011-76026.

(Production of polarizing plate PL4)

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the obtained optical film F4 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m to obtain a laminate .

(Drawing process)

The laminate thus obtained was stretched at 150 deg. C in a longitudinal direction (MD direction) with a roll roll at a draw ratio of 6, to obtain a drawn laminate.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL4. Further, the thickness of the obtained base layer (F4 (after stretching) in PL4 was 45 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL4 was 2 占 퐉.

(Production of optical film F5)

On the basis of the description of Example 1 of Japanese Patent Laid-Open Publication No. 2009-192844, a laminated film F5 (185 mu m thick) was obtained.

(Production of polarizing plate PL5)

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the obtained optical film F5 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m to obtain a laminate .

(Drawing process)

The laminate thus obtained was heated to 150 DEG C in a clip type tenter and stretched twice in the film width direction (TD direction), and then stretched at 150 DEG C in a longitudinal direction (MD direction) with a draw ratio of 5 Followed by stretching to obtain an oriented laminate.

(Dyeing treatment)

The stretched laminate thus prepared was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was performed at 60 캜 for 4 minutes to obtain a polarizing plate PL5. The thickness of the base layer (F5 (after stretching) in the obtained PL5 was 25 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL5 was 0.5 mu m.

(Production of optical film F6)

(Preparation of Dope Liquid a)

50 parts by mass of diacetylcellulose (L50, manufactured by Daicel)

Methylene chloride 227 parts by mass

Ethanol 43 parts by mass

The above materials were placed in a pressure-tightly sealed container, heated at 80 DEG C, and the resin component was completely dissolved while stirring at 2 atmospheric pressure to obtain a dope. (Manufactured by Asahi Glass Co., Ltd.). 244, and the dope was lowered to 35 DEG C and allowed to stand overnight to carry out defoaming in the dope.

(Preparation of Dope Liquid b)

100 parts by mass of Dianal BR-52 (acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.)

Methylene chloride 252 parts by mass

48 parts by mass of ethanol

The above materials were placed in a pressure-tightly sealed container, heated at 80 DEG C, and the resin component was completely dissolved while stirring at 2 atmospheric pressure to obtain a dope. (Manufactured by Asahi Glass Co., Ltd.). 244, and the dope was lowered to 35 DEG C and allowed to stand overnight to carry out defoaming in the dope.

(Preparation of base layer by solution casting method)

The dope liquid b prepared above was uniformly plied to a 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 amount of residual solvent became 100%, and peeled off on a stainless steel band support with a peel tension of 162 N / m.

The peeled web was dried at a drying temperature of 135 DEG C while evaporating the solvent at 35 DEG C and slitting it with a width of 1.6 m and then stretching it 1.1 times in the width direction in the tenter.

At that time, the amount of the residual solvent when the stretching was started in the tenter was 10%. After the stretching in the tenter, the film was relaxed at 130 占 폚 for 5 minutes. Then, the drying zone was transferred to a plurality of rolls at 120 占 폚 and 130 占 폚, and the film was slit with a width of 1.5 m. And was 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 an optical film.

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 residual solvent amount was 0.1%, the film thickness was 60 μm, and the number of windings was 4000 m.

Subsequently, the wound film was loosened, and the dope liquid a prepared above was plied on the unwound film and dried at 50 DEG C until the amount of the residual solvent in the resin layer containing the dope liquid a became 100% Thereafter, drying was performed stepwise at 120 ° C and 130 ° C, and drying was carried out until the amount of residual solvent in the film total became 0.3%. Thereafter, the film was wound up to obtain an optical film F6. The thickness of the resin layer including the dope liquid a was 15 占 퐉.

(Production of polarizing plate PL6)

(Lamination step)

The obtained polyvinyl alcohol aqueous solution was coated on the resulting optical film F6 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m, .

(Drawing process)

The laminate thus obtained was heated at 150 占 폚 in a clip tenter, stretched twice in the film width direction, and stretched at 150 占 폚 in a longitudinal direction (MD direction) with a roll roll of a conveying roll at a draw ratio of 5 times, I got a sieve.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL6. Further, the thickness of the substrate layer (after stretching) of PL6 obtained was 15 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL6 was 0.5 mu m.

(Production of polarizing plates PL7 and PL8)

In the production method of PL1, when a polyvinyl alcohol aqueous solution was coated on the obtained optical film F1, polyvinyl alcohol was coated so that the thickness of the finished coating layer was 25 占 퐉 or 32 占 퐉, respectively, to obtain a laminate.

Thereafter, the polarizing plates PL7 and PL8 were prepared in the same manner as in the production method of PL1.

(Production of polarizing plate PL9)

In the production method of the optical film F1, the dope liquid b thus prepared was softened in a stainless steel band support at a temperature of 22 占 폚 and a width of 2 m by using a belt softener so that the finished film thickness of the optical film F1 was 250 占 퐉 Respectively. Then, in the stainless steel band support, the solvent was evaporated for a sufficient time until the residual solvent amount became 100%, and peeled off on the stainless steel band support with a peel tension of 100 N / m.

The peeled web was dried at a drying temperature of 135 DEG C while evaporating the solvent at 35 DEG C and slitting it with a width of 1.6 m and then stretching it 1.1 times in the width direction in the tenter.

At this time, the amount of the residual solvent when the stretching was started in the tenter was 15%. After the stretching in the tenter, the film was relaxed at 130 占 폚 for 5 minutes. Then, the drying zone was transferred to a plurality of rolls at 120 占 폚 and 130 占 폚, and the film was slit with a width of 1.5 m. And an optical film was obtained by winding with an inner diameter of 6 inches core at an initial tension of 300 N / m and a final tension of 180 N / m.

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 residual solvent amount was 0.1%, the film thickness was 250 m, and the number of windings was 1000 m.

Subsequently, the wound film was loosened, and the dope liquid a prepared above was plied on the unwound film and dried at 50 DEG C until the amount of the residual solvent in the resin layer containing the dope liquid a became 100% Thereafter, drying was carried out stepwise at 120 DEG C and 130 DEG C, and drying was performed until the amount of the residual solvent in the film became 0.3%. Thereafter, the film was wound up to obtain an optical film F9. The thickness of the resin layer including the dope liquid a was 15 占 퐉.

(Lamination step)

The obtained polyvinyl alcohol aqueous solution was coated on the resulting optical film F9 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m, .

(Drawing process)

The laminate thus obtained was heated at 145 占 폚 in a clip tenter, stretched twice in the film width direction, and stretched at 145 占 폚 in a longitudinal direction (MD direction) with a roll roll of a conveying roll at a stretching magnification of 6 times, I got a sieve.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL9. Further, the thickness of the obtained base layer (F9 (after stretching)) in PL9 was 93 탆. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL9 was 2 占 퐉.

(Production of polarizing plate PL10)

In the method for producing the optical film F1, the dope liquid b thus prepared was dyed so that the finished film thickness of the optical film F1 was 280 占 퐉 when the dope liquid b was plied to the stainless steel band support at a temperature of 22 占 폚 and a width of 2 m, Respectively. Then, in the stainless steel band support, the solvent was evaporated for a sufficient time until the residual solvent amount became 100%, and peeled off on the stainless steel band support with a peel tension of 100 N / m.

The peeled web was evaporated at 35 占 폚, slit to 1.6m width, and then dried at a drying temperature of 135 占 폚 while being stretched 1.1 times in the width direction in the tenter.

At this time, the amount of the residual solvent when the stretching was started in the tenter was 15%. After the stretching in the tenter, the film was relaxed at 130 占 폚 for 5 minutes. Then, the drying zone was transferred to a plurality of rolls at 120 占 폚 and 130 占 폚, and the film was slit with a width of 1.5 m. And an optical film was obtained by winding it on a 6-inch inner core at an initial tension of 300 N / m and a final tension of 180 N / m.

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 residual solvent amount was 0.1%, the film thickness was 280 μm, and the number of wound water was 1000 m.

Subsequently, the wound film was loosened, and the dope liquid a prepared above was plied on the released film and dried at 50 DEG C until the amount of the residual solvent in the resin layer containing the dope liquid a became 100% , And then dried stepwise at 120 캜 and 130 캜. Drying was carried out until the amount of the residual solvent in the film total was 0.3%, and thereafter, the film was wound up to obtain an optical film F10. The thickness of the resin layer including the dope liquid a was 15 占 퐉.

(Lamination step)

The polyvinyl alcohol aqueous solution prepared above was coated on the obtained optical film F10 and dried at 120 DEG C for 10 minutes to form a hydrophilic polymer layer containing a polyvinyl alcohol coating film having a thickness of 10 mu m, .

(Drawing process)

The laminate thus obtained was heated at 145 占 폚 in a clip tenter, stretched twice in the film width direction, and stretched at 145 占 폚 in a longitudinal direction (MD direction) with a roll roll of a conveying roll at a stretching magnification of 6 times, I got a sieve.

(Dyeing treatment)

The stretched laminate thus prepared was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, the resultant was dried at 60 DEG C for 4 minutes to obtain a polarizing plate PL10. The thickness of the obtained base layer (F10 (after stretching) in PL10 was 103 mu m. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL10 was 2 占 퐉.

(Production of polarizing plate PL11)

A polarizing plate PL11 (thickness: 41 mu m) was produced by the method described in Example 1 of JP-A-2009-98653.

(Production of polarizing plate PL12)

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.

A 2.5 mass% aqueous solution of polyvinyl alcohol was directly applied to both surfaces of the polarizer prepared above, and the optical film F3 saponified under the following conditions was bonded and dried to obtain a polarizing plate PL12. The thickness of the obtained PL12 was 92 占 퐉.

(Saponification treatment)

The prepared optical film F3 was immersed in a KOH aqueous solution of 50 DEG C and 2.0 N for 60 seconds, and then subjected to water washing treatment.

(Production of polarizing plate PL13)

An optical film F4 was produced on the basis of Examples (a) and (b) of Japanese Patent Application Laid-Open No. 2010-250091. The optical film F3 prepared above was bonded to the optical film F4, and the polyvinyl alcohol aqueous solution prepared above was coated on the optical film F3 and then dried at 120 DEG C for 10 minutes to obtain a polyvinyl A hydrophilic polymer layer containing an alcohol coating film was formed to obtain a laminate.

(Drawing process)

The laminate thus obtained was stretched at 160 DEG C in a longitudinal direction (MD direction) at a stretching magnification of 2X with a roll roll to obtain a stretched laminate.

(Dyeing treatment)

The stretched laminate thus obtained was immersed in an iodine solution (mass ratio: iodine / potassium iodide / water = 1/10/100) at 30 ° C for 60 seconds while maintaining the tension. Thereafter, drying was carried out at 60 DEG C for 4 minutes to obtain a polarizing plate PL13. The thickness of the substrate layer in the obtained PL13 was 40 占 퐉. The thickness of the hydrophilic polymer layer (after stretching) in the polarizing plate PL13 was 3 占 퐉.

&Lt; Evaluation of physical properties of polarizer &

(Curl evaluation)

The measurement of the curl can be carried out by using a mold for measuring curl in Method A of "photographic film curl measurement method" of JIS K-7619-1988, and after the sample has been humidified for 10 hours under an environment of 25 ° C and 60% RH, . 23 ℃ and as the value of the curl C ₁ under a 55% RH environment, and d the value of the curl C ₂ under 40 ℃ 20% RH environment, the difference ΔC = | yielded | C ₁ -C _2. The results are shown in Table 1 below.

(Evaluation of elastic modulus)

The following evaluation was carried out using a tensilon tester (RTC-1225A, manufactured by ORIENTEC).

Each of the polarizing plates was cut to 120 mm (length) x 10 mm (width), and then the substrate layer was peeled off from each layer and the upper and lower portions were sandwiched with chucks 100 mm (holding value 10 mm above and below) min, and three times in the MD direction and the TD direction, respectively, and the average value thereof was calculated. Ea is the elastic modulus of the base layer on the side of the hydrophilic polymer layer, and Eb is the elastic modulus of the base layer on the opposite side of the hydrophilic polymer layer. The difference? E = | Ea-Eb | (MPa) was calculated. The elastic modulus Ea and the elastic modulus Ea are respectively represented by Ea ₁ and Eb ₁ under an environment of 23 ° C and 55% RH, and the elastic moduli Ea and Eb, respectively, under an environment of 40 ° C and 20% RH are represented by Ea ₂ and Eb ₂ , respectively. | Ea ₁ -Ea ₂ | And? Eb = | Eb ₁ -Eb ₂ |. The results are shown in Table 1 below.

<Evaluation of Liquid Crystal Display Device>

The polarizing plate pre-bonded to the 42-type television LEDREGZA 42RE1 manufactured by LG Electronics, an IPS-type liquid crystal display device, was peeled off and the polarizing plates PL1 to PL12 fabricated in the above manner were oriented in the same direction as the polarizing plate And a liquid crystal display device was produced. One side of Konica Minolta Tact KC4UY manufactured by Konica Minolta Opto Corporation was subjected to saponification treatment and the saponified surface was bonded to the surface of the hydrophilic polymer layer of each polarizing plate opposite to the surface on which the base layer was formed. When the polarizing plate was bonded to the liquid crystal display, the Konica Minolta tact KC4UY was bonded to the liquid crystal panel side using an adhesive.

Thereafter, the display device was allowed to stand in an environment of 23 ° C and 55% RH for 2 hours, and then the power source (backlight) was turned on, and the display irregularities and light leakage in each of the 12- , And evaluated by the following criteria. The results are shown in Table 1 below.

(Display unevenness)

Image display is uniform: ◎

Image display is almost uniform: ○

There are variations in the center and periphery:

There is a clear disturbance in the center and around: X

(Light leakage)

No light leakage: ◎

There is a little light leakage: ○

There is some light leakage and it feels bright: △

There is light leakage, and it feels dazzling: ×

As is clear from the results shown in Table 1, it can be seen that the liquid crystal display device used in the constitution of the present invention can obtain a uniform image quality free from unevenness and light leakage.

Claims (14)

A polarizing plate having a stretched laminate wherein a laminate of a base layer comprising a hydrophilic polymer layer and a thermoplastic resin is stretched and a dichroic material is adsorbed on the hydrophilic polymer layer,
The difference ΔC = | C ₁ -C ₂ | between curl C ₁ under 23 ° C. and 55% RH and curl C ₂ under 40 ° C. and 20% RH environment satisfies ΔC 80 [1 / m]
Wherein the substrate layer comprises at least
A first base layer comprising a first thermoplastic resin,
And a second base layer comprising a second thermoplastic resin disposed on the side opposite to the hydrophilic polymer layer with respect to the first base layer,
The difference ΔE = | Ea-Eb | (MPa) between the elastic modulus Ea of the first base layer and the elastic modulus Eb of the second base layer satisfies? E? 3000 MPa,
The difference in elastic modulus Ea ₁ and Eb ₁ under an environment of 23 ° C and 55% RH and the modulus of elasticity Ea ₂ and Eb ₂ under an environment of 40 ° C and 20% RH, ΔEa = | Ea ₁ -Ea ₂ | And? Eb = | Eb ₁ -Eb ₂ | satisfies? Ea and? Eb? 2000 [MPa]. The polarizer according to claim 1, wherein the base layer contains at least two kinds of thermoplastic resins. The polarizing plate according to claim 1 or 2, wherein the hydrophilic polymer layer has a film thickness of 0.5 to 30 占 퐉. 3. The thermoplastic resin composition according to claim 1 or 2, wherein the thermoplastic resin contained in the base layer comprises an acrylic resin, a styrene resin, a cycloolefin resin, a cellulose resin, a polypropylene resin, a polyester resin, Polarizing plate. The method according to claim 1 or 2, wherein the first thermoplastic resin is a cellulose resin, the second thermoplastic resin is an acrylic resin,
Wherein the? C satisfies? C? 60 [1 / m]. The polarizing plate according to claim 1 or 2, wherein the stretched laminate has a thickness of 10 to 100 탆. The polarizing plate according to claim 1 or 2, wherein the hydrophilic polymer layer comprises polyvinyl alcohol as a hydrophilic polymer. The polarizer according to claim 1 or 2, wherein the dichroic substance is iodine. A method for producing a polarizing plate according to claim 1,
And a step of forming the base layer by a solution casting method. The manufacturing method according to claim 9, further comprising a step of applying a solution containing a hydrophilic polymer to one surface of the formed base material layer and drying to obtain a laminate. The method according to claim 10, further comprising a step of stretching the laminate at a draw magnification of 2 to 10 times. A polarizing plate according to claim 1 or 2 or a polarizing plate produced by the manufacturing method according to claim 10 or claim 11. 13. The display device according to claim 12, being an IPS mode liquid crystal display. delete