KR101763509B1 - Polarizing plate and liquid crystal display device using same - Google Patents

Abstract

The present invention provides a means for improving the workability of a polarizing plate in which a thin cellulose ester film is used as one protective film. A protective film A, a polarizer and a protective film B in this order, wherein the protective film A is a polyester film comprising a polyester, and the polyester film has a refractive index of 5.0 to 5.0 in at least one of the MD direction and the TD direction, (1) the film thickness is in the range of 15 to 60 탆, (2) the cellulose ester film has the MD direction and the TD Direction and a toughness of 10 to 20 with respect to both directions.

Description

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

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

BACKGROUND ART Liquid crystal display devices are in increasing demand for applications such as liquid crystal TVs and liquid crystal displays for personal computers. The liquid crystal display device is generally constituted by a liquid crystal cell in which a transparent electrode, a liquid crystal layer, a color filter and the like are sandwiched between glass plates and two polarizing plates provided on both sides thereof. Each of the polarizing plates is constructed so as to hold a polarizer with two sheets of transparent resin film. As one of such transparent resin films, a cellulose ester film such as cellulose acetate is often used for the purpose of protecting the polarizer (see, for example, International Publication No. 2011/016279). The cellulose ester film has a high transmittance and is immersed in an aqueous alkali solution to saponify the surface of the cellulose ester film and hydrophilize, thereby realizing excellent adhesion with the polarizer.

2. Description of the Related Art In recent years, a polarizing plate has been required to be thinner in a form that responds to demands for enlargement and thinning of a display. Needless to say, a cellulose ester film as a protective film which is a constituent member of a polarizing plate also strongly demands a thin film. However, when the cellulose ester film as the protective film is thinned, there is a problem that the reworkability of the polarizing plate is deteriorated. That is, when the polarizing plate formed by thinning the protective film is bonded to the liquid crystal cell, when the polarizing plate is peeled off from the liquid crystal cell when the polarizing plate is separated from the liquid crystal cell, there arises a problem that the polarizing plate can not be easily peeled off, There has been a problem that the productivity of the display device is lowered.

However, conventionally, it has also been proposed to use a resin film other than a cellulose ester film as a protective film of a polarizing plate. For example, in Japanese Patent Laid-Open Publication No. 256057/1995, when a polyester film containing polyethylene terephthalate or the like is used as a protective film of a polarizing plate, the retardation of the film controlled to a predetermined value is combined with a specific light source It is specified that a polarizing plate excellent in durability and visibility is provided. However, the fact that such a polyester film can be used as a protective film of a polarizing plate to improve the lithographic properties as described above has heretofore not been known at all.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a problem to be solved is to provide a means for improving the lithography workability in a polarizing plate in which a cellulose ester film of a thin film is used as one protective film.

As a result of intensive studies in view of the above problems, the present inventors have found that, in a polarizing plate having a protective film A, a polarizer and a protective film B in this order, a polyester film containing a polyester is used as the protective film A, Further, it is preferable that the polyester film has a modulus of elasticity of 5.0 to 8.0 mm in at least one of the MD direction and the TD direction, and that a cellulose ester film containing cellulose ester is used as the protective film B and the cellulose ester film (1) the film thickness is in the range of 15 to 60 탆, and (2) the toughness is 10 to 20 in both of the MD direction and the TD direction, whereby a thin film of a cellulose ester film is used as the protective film B It is possible to realize a polarizing plate excellent in reworkability even in the case of the present invention, leading to the present invention.

That is, the above object of the present invention is solved by the following means.

1. A polarizing plate having a protective film A, a polarizer and a protective film B in this order,

Wherein the protective film A is a polyester film comprising a polyester,

The polyester film has a modulus of elasticity of 5.0 to 8.0 mm in at least one of the MD direction and the TD direction,

The protective film B is a cellulose ester film containing a cellulose ester,

In the cellulose ester film,

(1) the film thickness is in the range of 15 to 60 탆,

(2) a toughness of 10 to 20 in both the MD direction and the TD direction,

A polarizing plate;

2. The polarizing plate according to the above 1, wherein the polyester is polyethylene terephthalate.

3. The polarizing plate according to 1 or 2, wherein the protective film A has a thickness in the range of 40 to 100 mu m.

4. The retardation film according to claim 1, wherein the in-plane retardation Ro defined by the following formulas (i) and (ii) is in the range of 30 to 70 nm and the retardation value Rt in the thickness direction is 100 to 140 1 > to < 3 >

Formula (i): Ro = (n x -n y) × d (㎚)

Formula (ii): Rt = {( n x + n y) / 2-n z} × d (㎚)

Wherein n _x represents a refractive index in a direction x at which the refractive index becomes maximum in an in-plane direction of the film and n _y represents a refractive index in an in-plane direction of the film in a direction orthogonal to the direction x represents the refractive index in, n _z it is, represents the refractive index of the thickness direction z of the film, and d is each represents the thickness (㎚) of the film, measurement environment 23 ℃ · 55% to the measurement of the RH 590㎚ Wave length]

5. The polarizing plate according to any one of 1 to 4 above, wherein the cellulose ester contains cellulose acetate as a main component.

6. The polarizing plate according to 5 above, wherein the acetyl group substitution degree of the cellulose acetate is 2.1 to 2.95.

7. The polarizing plate according to any one of items 1 to 6, wherein the protective film B comprises a retardation-increasing agent.

Wherein the retardation increasing agent is represented by the following formula (1):

(Wherein R ¹ to R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a halogen atom;

X each independently represents -O- or -O-C (= O) - (wherein O is bonded to the phenyl skeleton in formula (1));

R ⁵ and R ⁶ are each independently

An alkyl group which may be substituted with a hydroxyl group, an ester group or an optionally substituted aromatic group when X is -O-; Or a glycidyl group,

An alkyl group which may be substituted with a hydroxyl group, an ester group or an optionally substituted aromatic group when X is -O-C (= O) -; Or an aromatic group which may be substituted)

The polarizing plate according to the above 7, wherein the polarizing plate comprises a compound represented by the formula

9. The polarizing plate according to any one of 1 to 8 above, wherein the protective film A and the protective film B are all bonded to the polarizer by an ultraviolet curable adhesive.

10. The polarizer according to any one of items 1 to 9 above, wherein the film thickness of the polarizer is within a range of 2 to 15 占 퐉.

11. The polarizer according to any one of the above 1 to 10, wherein the thickness is within a range of 80 to 150 占 퐉.

12. A liquid crystal display device comprising the polarizing plate according to any one of 1 to 11 above.

1 is a schematic cross-sectional view showing an example of a polarizing plate structure of the present invention.
Fig. 2 is a diagram schematically showing an example of a dope manufacturing process, a softening process and a drying process (solvent evaporation process) of the solution casting method of a preferred embodiment of the present invention.

The polarizing plate according to the present invention is a polarizing plate having a protective film A, a polarizer and a protective film B in this order, wherein the protective film A is a polyester film comprising a polyester, And the protective film B is a cellulose ester film containing a cellulose ester, and the cellulose ester film is a cellulose ester film having a modulus of elasticity of at least 5.0 to 8.0,

(1) the film thickness is in the range of 15 to 60 탆,

(2) a toughness of 10 to 20 in both the MD direction and the TD direction,

. According to the polarizing plate of the present invention, even when a thin film of cellulose ester film is used as one protective film, it is possible to improve the lithography workability.

With respect to the technical reasons for achieving the object of the present invention by the above-described constitution specified by the present invention, the details of the mechanism are not clarified, but the present invention has been completed through the following hypothesis and verification process .

In other words, the present inventors have conducted intensive studies on the characteristics of the polarizing plate having the protective film A, the polarizer and the protective film B in this order in view of the above problems. In the process, it has been hypothesized that the decrease in the tearing strength of the polarizing plate is caused by the decrease in reworkability when a thin film of a cellulose ester film is used as the protective film B. Furthermore, it was confirmed that the use of a polyester film having a high tear strength as the protective film A showed an improvement in reworkability, and the hypothesis was proved. Thereafter, in order to obtain a polarizing plate with further improved reworkability, the properties of the polyester film constituting the protective film A were variously changed, and the performance of the polarizing plate was examined. As a result, a polyester film having an elastic modulus in a predetermined range was used In particular, it has been found that excellent reworkability can be achieved. On the other hand, by using such a protective film A, it was confirmed that a cellulose ester film can be used as the protective film B in the conventional manner, and the lower limit value of toughness is obtained as the physical properties required for the cellulose ester film to complete the present invention It is to come to do.

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

&Quot; Polarizer "

Hereinafter, the details of each component of the polarizing plate of the present invention will be described.

[Composition of Polarizer]

The protective film A is a polyester film (for example, a polyethylene terephthalate film), and the protective film B is a cellulose ester film (for example, a cellulose ester film). The polarizing plate of the present invention has a protective film A, a polarizer, For example, a cellulose acetate film.

1 is a schematic cross-sectional view showing an example of the configuration of a polarizing plate of the present invention. 1, the polarizing plate 101 of the present invention has a polyethylene terephthalate film 102 which is a protective film A and a polarizer 104 from the surface side, and the polyethylene terephthalate film 102 and the polarizer 104 ) Are adhered by the ultraviolet curable adhesive layer 103A. The ultraviolet curable adhesive layer 103A is made of a material which is cured by irradiating ultraviolet rays or the like. Details of the ultraviolet curable adhesive will be described later.

The polarizing plate 101 shown in Fig. 1 further includes an ultraviolet curable adhesive layer 103B on the surface of the polarizer 104 opposite to the surface on which the polyethylene terephthalate film 102, which is the protective film A, A cellulose acetate film 105, which is a protective film B, is laminated.

Although not shown in Fig. 1, even if an antiglare layer, antireflection layer, antifouling layer, hard coat layer or the like is formed on the outer side (outermost surface portion) of the polyethylene terephthalate film 102 do.

[Protective film A]

The protective film A is a polyester film containing a polyester. As a concrete form of this polyester film, conventionally known knowledge can be suitably referred to, except that the elasticity is within a predetermined range. Concretely, the polyester film constituting the protective film A used in the polarizing plate according to the present invention has a thickness of 5.0 to 8.0 ㎬, preferably 5.5 to 7.0 ㎬, more preferably 5.8 Lt; / RTI > to 6.5 mm. When the modulus of elasticity is low, the reworkability of the polarizing plate is deteriorated, and a film having a high elastic modulus is difficult to manufacture. Further, it preferably has the predetermined elastic modulus with respect to both of the MD direction and the TD direction. As the elastic modulus value of the polyester film, a value measured by a measuring method described in the column of Examples to be described later will be adopted.

As the polyester constituting the polyester film, polyethylene terephthalate or polyethylene naphthalate can be used, but other copolymerizable components may be contained. These resins are excellent in transparency, excellent in thermal and mechanical properties, and can easily control retardation by stretching. In particular, polyethylene terephthalate is the most suitable material because it has a large intrinsic birefringence and a relatively large retardation even when the thickness of the film is thin.

Further, for the purpose of suppressing deterioration of the optically functional dye such as iodine dye, it is preferable that the light transmittance of light having a wavelength of 380 nm in the protective film A is 20% or less. The light transmittance is more preferably 15% or less, further preferably 10% or less, particularly preferably 5% or less. When the light transmittance is 20% or less, deterioration due to ultraviolet rays of the optically functional dye can be suppressed. The transmittance in the present invention is measured in a direction perpendicular to the plane of the film, and can be measured using a spectrophotometer (for example, Hitachi U-3500 type).

Here, in order to reduce the light transmittance of the protective film A to 20% or less, it is preferable to appropriately adjust the kind, concentration and film thickness of the ultraviolet absorbent. The ultraviolet absorber used in the present invention is a known substance. As the ultraviolet absorber, an organic ultraviolet absorber and an inorganic ultraviolet absorber can be mentioned, but from the viewpoint of transparency, an organic ultraviolet absorber is preferable. When two or more kinds of ultraviolet absorbers are used in combination, ultraviolet rays of respective wavelengths can be simultaneously absorbed, so that the ultraviolet absorption effect can be further improved.

Among ultraviolet absorbers, an ultraviolet absorber having a molecular weight of 400 or more is difficult to sublimate, or is difficult to volatilize due to a high boiling point, and is hardly scattered even when the film is dried at high temperature. Therefore, the addition of a relatively small amount can effectively improve weatherability .

Examples of the ultraviolet absorber having a molecular weight of not less than 400 include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- (1,1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4- Peridyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and the like, and further 2- (3,5- (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di 4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t- butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 , And 6-tetramethylpiperidine. These may be used either singly or in combination of two or more. Examples of the hindered phenol include hindered phenol and hindered amine. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

As ultraviolet absorbers, commercially available products may be used. Examples of such ultraviolet absorbers may include commercially available products such as TiNUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328 and TINUVIN 928 manufactured by BASF Japan (1,1,3,3-tetramethylbutyl) phenol] (molecular weight: 659, commercially available products), or a mixture of 2,2'-methylenebis [6- (2H-benzotriazol- LA31 manufactured by ADEKA Corporation) can be preferably used.

The ultraviolet absorbers may be used singly or in combination of two or more.

In addition to the ultraviolet absorber, it is also a preferable embodiment to contain various additives in a range not hindering the effect of the present invention. Examples of the additive include inorganic particles, heat resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, light stabilizers, flame retardants, heat stabilizers, antioxidants, antigelling agents and surfactants. Further, in order to exhibit high transparency, it is also preferable that the polyester film contains substantially no particles. The phrase " the polyester film is substantially free from particles " means that, for example, in the case of inorganic particles, 50 mass ppm or less, preferably 10 mass ppm or less, when the inorganic element is quantified by fluorescent X- Preferably a content below the detection limit.

The polyester film constituting the protective film A may be subjected to a corona treatment, a coating treatment, a flame treatment or the like in order to improve the adhesiveness with the polarizer.

Further, as described in Patent Document 2, when a white light emitting diode is used as a backlight source of a liquid crystal display device, it is preferable to control the retardation value of the polyester film to a value within a predetermined range. Specifically, the polyester film used for the protective film A preferably has retardation of 3,000 to 30,000 nm. When the retardation is less than 3000 nm, when the film is used as a protective film, it exhibits a strong interference color when observed in an oblique direction, so that the envelope shape differs from the light emission spectrum of the light source and it is difficult to ensure good visibility . The lower limit value of the preferable retardation is 4500 nm, the lower limit value next is preferably 5000 nm, the more preferable lower limit value is 6000 nm, the more preferable lower limit value is 8000 nm, and the particularly preferable lower limit value is 10000 nm.

On the other hand, the upper limit value of the retardation of the polyester film is preferably 30000 nm, more preferably 20000 nm. Even if a polyester film having a retardation higher than that is used as the protective film A, the effect of further improving the visibility is not substantially obtained, the thickness of the film is considerably increased, and the handling property as an industrial material is lowered have.

In the present invention, the retardation value of the protective film A can be obtained by measuring the refractive index and the thickness in the biaxial direction, or can be obtained by measuring the birefringence of a commercially available birefringent film such as KOBRA-21ADH (Oji Kiso Kikin Kiki K.K.) And can also be obtained by using a measuring device.

The polyester film constituting the protective film A can be produced by a general method for producing a polyester film. For example, an unoriented polyester extruded into a sheet form by melting a polyester resin is stretched in the longitudinal direction at a temperature equal to or higher than the glass transition temperature using the speed difference of the roll, and then stretched in the transverse direction Followed by stretching and heat treatment.

The polyester film of the present invention may be a uniaxially stretched film or a biaxially stretched film. However, when a biaxially stretched film is used as a polarizer protective film, no irregular color unevenness is observed even when viewed from directly above the film surface, The color irregularity of a rainbow shape may be observed. In this phenomenon, the biaxially stretched film is made of a refractive index ellipsoid having a different refractive index in the running direction, the width direction, and the thickness direction, and has a retardation of zero according to the transmission direction of light inside the film (the refractive index ellipsoid ) Direction. Therefore, when the liquid crystal display screen is observed in a specific direction in the oblique direction, there is a case where a point where retardation becomes zero is generated, and irregular color unevenness occurs concentrically around the point. When the angle from the position immediately above the film surface (normal direction) to the position where the irregular color unevenness is visible is denoted by?, The angle? Increases as the birefringence in the film surface becomes larger, and irregular color irregularities become less visible. Since the angle &thetas; tends to decrease in the biaxially stretched film, it is preferable that the uniaxially stretched film is less likely to show irregular color irregularities.

However, in the case of a complete monoaxial (uniaxial symmetric) film, mechanical strength in a direction immediately to the alignment direction is remarkably lowered, which is not preferable from the viewpoint of improvement in reworkability. In the present invention, the polyester film may preferably have a biaxial (biaxial) symmetry property in a range that does not cause color irregularity of a substantially irregular shape, or a range of viewing angles required for a liquid crystal display screen, ).

The thickness of the polyester film constituting the protective film A is not particularly limited, but is preferably 40 to 100 占 퐉, and more preferably 60 to 95 占 퐉. If the film thickness of the polyester film is 40 탆 or more, the protective film A having an excellent anisotropy of the dynamic characteristics of the film is hardly produced and excellent in mechanical strength can be constituted. When the film thickness of the polyester film is 100 m or less, it is preferable because the thickness of the polarizing plate is prevented from increasing.

Next, the film forming conditions of the polyester film will be described in detail.

In order to control the value of the modulus of elasticity of the polyester film to the above-mentioned range, it is preferable that the polyester which is the film-forming raw material of the film is subjected to filtration treatment twice or more in a molten state. By performing such a treatment, the polymer component (lumps) contained in the raw polyester can be removed, and the molecular weight distribution of the polyester can be made more sharp. The specific means of the filtration treatment is not particularly limited, and filtration treatment may be performed using a conventionally known filter material such as a stainless steel sintered body. Here, the filter particle size (initial filtration efficiency: 95%) of the filter medium is preferably 25 占 퐉 or less, and more preferably 10 占 퐉 or less.

Thereafter, the raw material polyester subjected to the filtration treatment is mixed with an additive such as an ultraviolet absorber, if necessary, and put in an extruder, melted, extruded from a T-die, and brought into close contact with a cooling roll to obtain an unstretched sheet . The unstretched sheet is stretched in the MD direction by stretching between rolls having a speed difference (roll stretching), and stretched by stretching (tenter stretching) by gripping and expanding by a clip if necessary, Stretched in the TD direction by stretching (inflation stretching) or the like, and finally biaxially oriented.

Here, first, the longitudinal stretching process of the first stage is elongated between two or more rolls having different circumferences. The stretching magnification (longitudinal stretching magnification) at this time is preferably 2 to 5 times, more preferably 3 to 5 times, particularly preferably 3 to 4 times. The heating means at this time may be a method using a heating roll or a method using a non-contact heating method, or may be used in combination. Among these, the most preferable stretching method is a method of using roll heating and non-contact heating. In this case, it is important to preliminarily heat the film to a relatively high temperature of 120 to 150 캜 from the viewpoint of increasing the modulus of elasticity of the polyester film. Thereafter, by heating with an infrared heater, it can be introduced into the transverse stretching step described later. The importance of this preliminary heating is also suitable for the case where the transverse stretching step is first carried out and then the longitudinal stretching step is carried out. The stretching temperature in the longitudinal stretching step is preferably 90 to 180 占 폚, and more preferably 100 to 180 占 폚.

Subsequently, the uniaxially stretched film thus obtained can be introduced into a tenter and stretched in the width direction. The stretching magnification (transverse stretching magnification) at this time is preferably 1 to 5 times, more preferably 2 to 5 times, still more preferably 2 to 4 times, particularly preferably 3 to 4 times. The stretching temperature in the transverse stretching step is preferably 90 to 180 占 폚, more preferably 100 to 150 占 폚. The biaxially stretched film thus obtained is subjected to heat treatment as necessary. The heat treatment is preferably carried out in a tenter, and it is preferable that the heat treatment is carried out in the range of the melting point Tm-50 ° C to Tm of the polyester.

From the viewpoint of increasing the elastic modulus of the polyester film, it is preferable to control the total value of the longitudinal stretching magnification and the transverse stretching magnification. Concretely, it is preferable to control the total value to 6.0 to 9.0, more preferably to control it to 6.0 to 8.0, and more preferably to control to 6.5 to 7.5.

As a method for blending the ultraviolet absorber with the polyester film constituting the protective film A, known methods can be used in combination. For example, by blending the dried ultraviolet absorber and the polymer raw material in advance using a kneading extruder, A batch may be prepared, and the desired master batch and the polymer raw material may be mixed at the time of film formation.

At this time, the concentration of the ultraviolet absorber in the master batch is preferably 5 to 30% by mass in order to uniformly disperse the ultraviolet absorber and to economically blend it. As a condition for producing the master batch, it is preferable to use a kneading extruder and extrude the extrudate at a temperature not lower than the melting point of the polyester raw material and not higher than 290 DEG C for 1 to 15 minutes. At a temperature higher than 290 占 폚, the weight loss of the ultraviolet absorber is large and the viscosity drop of the master batch becomes large. When the extrusion temperature is lower than the melting point -50 ° C, it becomes difficult to uniformly mix the ultraviolet absorber. At this time, a stabilizer, a color tone adjusting agent and an antistatic agent may be added as necessary.

The polyester film may have a multilayer structure of at least three layers and an ultraviolet absorber may be added to the intermediate layer of the film. The three-layer structure film containing the ultraviolet absorber in the intermediate layer can be specifically prepared as follows. A master batch containing a polyester pellet alone as an outer layer and an ultraviolet absorber as an intermediate layer and a polyester pellet are mixed at a predetermined ratio and dried, and then supplied to a known extruder for melt lamination, Extruded into a sheet form, and cooled and solidified on a casting roll to form an unstretched film. That is, by using two or more extruders, a three-layer manifold or a joining block (for example, a joining block having a rectangular joining portion), a film layer constituting both outer layers and a film layer constituting the intermediate layer are laminated, It is possible to form an unstretched film by extruding a three-layer sheet from the casting roll and cooling it on a casting roll.

[Protective film B]

The protective film B is a cellulose ester film containing a cellulose ester. As a specific form of the cellulose ester film, conventionally known knowledge can be suitably referred to, except that the film thickness and the toughness are within a predetermined range.

Specifically, the cellulose ester film constituting the protective film B used in the polarizing plate according to the present invention has a film thickness in the range of 15 to 60 탆, more preferably in the range of 20 to 40 탆 It is mine. When the film thickness of the cellulose ester film as the protective film B is 15 μm or more, sufficient strength is provided and excellent handling properties can be obtained. When the thickness is 60 μm or less, a polarizing plate of a thin film can be easily produced.

The cellulose ester film constituting the protective film B used in the polarizing plate according to the present invention is characterized by having a toughness of 10 to 20 in both the MD and TD directions, more preferably 15 to 20 Lt; / RTI > The present inventors have found that by controlling the toughness value of a cellulose ester film to such a range and then forming a polarizing plate together with the protective film A including a polyester film having the elastic modulus as described above, It is possible to realize a polarizing plate having excellent reworkability even when used as the protective film B. As the toughness value of the cellulose ester film, a value measured by the measuring method described in the column of the following example will be adopted.

(Cellulose ester)

The cellulose ester (cellulose ester resin) is a cellulose ester in which some or all of the hydrogen atoms of the hydroxyl groups (-OH) at the 2nd, 3rd and 6th positions in the? -1,4-linked glucose units constituting cellulose are substituted with acyl groups Cellulose acylate resin.

The cellulose ester contained in the film of this embodiment is not particularly limited, but is preferably a linear or branched carboxylic acid ester having about 2 to 22 carbon atoms. The carboxylic acid constituting the ester may be an aliphatic carboxylic acid, a ring, or an aromatic carboxylic acid. For example, when the hydrogen atom of the hydroxyl group portion of the cellulose is substituted with 2 or more carbon atoms such as acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, pivaloyl group, hexanoyl group, octanoyl group, lauroyl group, Lt; / RTI > to < RTI ID = 0.0 > 22 < / RTI > The carboxylic acid (acyl group) constituting the ester may have a substituent. The carboxylic acid constituting the ester is preferably a lower fatty acid having 2 to 6 carbon atoms, more preferably a lower fatty acid having 2 to 4 carbon atoms, and more preferably a lower fatty acid having 2 or 3 carbon atoms. The acyl group in the cellulose ester may be a single species or a combination of plural acyl groups.

Specific examples of preferred cellulose esters include acetyl groups such as cellulose acetate propionate (CAP), cellulose acetate butyrate, cellulose acetate propionate butyrate in addition to cellulose acetate (diacetylcellulose (DAC), triacetylcellulose And mixed fatty acid esters of cellulose having a propionate group or a butyrate group bonded thereto. Preferably cellulose acetate, cellulose acetate butyrate or cellulose acetate propionate, particularly preferably cellulose acetate. In the present invention, the cellulose ester constituting the protective film B preferably contains cellulose acetate as a main component from the viewpoints of handleability and film-forming suitability. Here, the expression " included as the main component " means that the content of cellulose acetate is 50 mass% or more with respect to the entire amount of the cellulose ester. The content of the cellulose acetate is preferably 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 98% by mass or more with respect to the total amount of the cellulose ester %, And most preferably 100 mass%.

The butyryl group which may be contained in the cellulose ester may be linear or branched. These cellulose esters may be used singly or in combination of plural kinds.

The total degree of substitution (total acyl group degree of substitution) of the acyl group of the cellulose ester may be about 1.0 to 3.0. The total degree of substitution of the acyl group is preferably in the range of 2.0 to 2.95, more preferably 2.1 to 2.7, from the viewpoint of lowering the moisture permeability. When the cellulose ester contains cellulose acetate as a main component, the acetyl group substitution degree of the cellulose acetate is preferably 2.1 to 2.95, more preferably 2.2 to 2.75 from the viewpoint of film forming suitability and film strength And more preferably 2.2 to 2.6. In the range of 2.2 to 2.75, the film is hard, the tear strength is good, and in the range of 2.2 to 2.6, the visibility is particularly good when used as the retardation. The degree of substitution of the acyl group of the cellulose ester can be measured by the method defined in ASTM-D817-96.

The degree of substitution of the acyl group represents the average number of acyl groups per glucose unit and indicates whether some of the hydrogen atoms of the second, third and sixth hydroxyl groups of one glucose unit are substituted with acyl groups. Thus, the maximum degree of substitution is 3.0, which means that the hydrogen atoms of the second, third, and sixth hydroxyl groups are all substituted with acyl groups. These acyl groups may be substituted on the average, in the second, third or sixth position of the glucose unit, or may be substituted with a distribution. The degree of substitution is obtained by the method defined in ASTM-D817-96.

Cellulose acetate having different degree of substitution may be mixed and used to obtain desired optical properties. The mixing ratio of the different cellulose acetate is not particularly limited.

The number average molecular weight of the cellulose ester is preferably in the range of 4 × 10 ⁴ to 3 × 10 ⁵ , more preferably 4.5 × 10 ⁴ to 2 × 10 ⁵ in order to increase the mechanical strength of the resulting film, And particularly preferably in the range of 5 × 10 ⁴ to 7 × 10 ⁴ . In the present specification, "weight average molecular weight (Mw)" and "number average molecular weight (Mn)" are values measured by gel permeation chromatography (GPC). The measurement conditions are as follows.

The content of the residual sulfuric acid in the cellulose ester is preferably in the range of 0.1 to 45 mass ppm in terms of sulfur element, more preferably in the range of 1 to 30 mass ppm. It is considered that sulfuric acid remains in the film in a salt state. When the content of the residual sulfuric acid exceeds 45 mass ppm, the film tends to break at the time of heat stretching or at the time of slitting after thermal stretching. The content of the residual sulfuric acid can be measured by the method defined in ASTM D817-96.

The content of the free acid in the cellulose ester is preferably in the range of 1 to 500 mass ppm, more preferably 1 to 100 mass ppm, further preferably 1 to 70 mass ppm. If the content of the free acid is within the above range, it is difficult for the film to break when heat-stretched or slit after thermal stretching, as described above. The content of the free acid can be measured by the method specified in ASTM D817-96.

The cellulose ester may contain a trace amount of a metal component. It is considered that a trace amount of the metal component is derived from the water used in the synthesis process of the cellulose derivative. As such a metal component, it is preferable that the content of the component that can be an insoluble core is as small as possible. Particularly, metal ions such as iron, calcium, magnesium and the like may form an insoluble matter by forming a salt with a resin decomposition product or the like, which may contain an organic acidic group. The calcium (Ca) component can easily form an acidic component such as a carboxylic acid or a sulfonic acid and also many ligands and a coordination compound (i.e., a complex), and can be used as a scum (insoluble sediment, turbidity) May be formed.

Concretely, the content of the iron (Fe) component in the cellulose ester is preferably 3 mass ppm or less, and more preferably 1 mass ppm or less. The content of the calcium (Ca) component in the cellulose derivative is preferably 60 mass ppm or less, and more preferably 0 to 30 mass ppm. The content of the magnesium (Mg) component in the cellulose ester is preferably in the range of 0 to 70 mass ppm, particularly preferably in the range of 0 to 20 mass ppm.

The content of the metal components such as iron (Fe) component, calcium (Ca) component and magnesium (Mg) component can be controlled by adjusting the amount of the cellulose ester to be completely dried (preliminarily dried) by a micro digest wet cracking device , And measurement can be performed using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer).

The content of the residual alkaline earth metal, residual sulfuric acid and residual acid can be adjusted by sufficiently washing the cellulose ester obtained by the synthesis.

Cellulose esters such as cellulose acetate, cellulose acetate propionate and the like can be produced by a known method. Generally, cellulose is mixed with a raw material cellulose and a predetermined organic acid (acetic acid, propionic acid, etc.), an acid anhydride (acetic anhydride, propionic anhydride, etc.), a catalyst (sulfuric acid, etc.), esterifies the cellulose, The reaction is allowed to proceed until the reaction is complete. In the triester, the three hydroxyl groups (hydroxyl groups) in the glucose unit are substituted with an acyl acid of an organic acid. When two kinds of organic acids are used at the same time, mixed ester-type cellulose esters such as cellulose acetate propionate and cellulose acetate butyrate can be produced. Subsequently, the cellulose ester resin having desired degree of acyl substitution is synthesized by hydrolyzing the triester of cellulose. Thereafter, the cellulose ester is completed through filtration, precipitation, washing, dehydration, drying and the like. Specifically, it can be synthesized by referring to the method described in JP-A-10-45804.

A commercially available cellulose ester may be used. Commercially available products include Diesell L20, L30, L40 and L50, and Ca398-3, Ca398-6, Ca398-10, Ca398-30 and Ca394-60S of Eastman Chemical Company.

(Retardation increasing agent)

The cellulose ester film as the protective film B preferably contains a retardation increasing agent. The term "retardation increasing agent" means an additive having a function of increasing the retardation of the cellulose ester film by the addition thereof. The specific form of the retardation raising agent is not particularly limited, and conventionally known knowledge can be suitably referred to.

Here, as a preferred form of the retardation increasing agent, for example, there can be mentioned a compound of the following formula (1). Needless to say, other retardation increasing agents may be used. The compound of the following formula (1) may increase the retardation value in the thickness direction of the cellulose ester film in particular and may further reduce the moisture permeability of the film. Further, the compound of the following formula (1) has low volatility even under high temperature and high humidity. As a result, the anti-bleeding property of the cellulose ester film can be improved, and as a result, the sharpness of the image can be improved.

In the above formula (1), R ¹ to R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a halogen atom. Here, R ¹ to R ⁴ may be the same or different from each other. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group and an isopropyl group. Among them, a hydrogen atom, a methyl group, an ethyl group, a fluorine atom and a chlorine atom are preferable from the viewpoint of the effect of improving the retardation value (in particular, the retardation value in the thickness direction of the film) and the compatibility with the cellulose ester. Particularly preferred.

In the above formula (1), each X independently represents -O- or -O-C (= O) -. Here, when X represents -O-C (= O) -, ether oxygen (-O-) of -O-C (= O) - is bonded to the phenyl skeleton of formula (1). Among them, X is preferably -O-.

In the above formula (1), R ⁵ and R ⁶ each independently have the following definitions.

When X is -O-, R ⁵ and R ⁶ are each independently an alkyl group which may be substituted with a hydroxyl group, an ester group or an optionally substituted aromatic group; Or a glycidyl group.

When X is -OC (= O) -, R ⁵ and R ⁶ are each independently an alkyl group which may be substituted with a hydroxyl group, an ester group or an aromatic group which may be substituted; Or an aromatic group which may be substituted.

The ester group capable of substituting the alkyl group is represented by the formula: -OC (= O) -R or -C (= O) -OR, wherein R is a linear or branched alkyl group having 1 to 8 carbon atoms or Aromatic group. The alkyl group and the aromatic group are the same as defined below.

Examples of the alkyl group as R ⁵ and R ⁶ include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, Is preferably a linear or branched alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, pentyl, hexyl, heptyl and octyl. Among these, an alkyl group having 1 to 5 carbon atoms is preferable, and an alkyl group having 2 to 4 carbon atoms is preferable.

The aromatic group may be an aryl group having 6 to 24 carbon atoms. Specific examples include a phenyl group, a p-tolyl group, a naphthyl group, a biphenyl group, a fluorenyl group, an anthryl group, a pyrenyl group, an azulenyl group, an acenaphthylenyl group, a terphenyl group and a phenanthryl group. Of these, a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable. The aromatic group may have a substituent. Examples of the substituent for substituting the aromatic group include, but not limited to, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a phenyl group, a methylphenyl group, a phenylphenyl group, a methylphenylphenyl group, (Fluorine atom, chlorine atom, bromine atom, iodine atom), nitro group and the like. The above substituents may be one or two or more, and in the latter case, the respective substituents may be the same or different. Of these, the aromatic group is preferably a phenyl group, a methylphenyl group, or a methylphenylphenyl group, from the viewpoint of improving the retardation value (in particular, the retardation value in the thickness direction of the film) and compatibility with the cellulose ester.

The production method of the compound represented by the formula (1) when R ⁵ and R ⁶ are each an alkyl group having a substituent is not particularly limited. Specifically, the compound can be obtained by reacting an epoxy compound with an aromatic monocarboxylic acid. Examples of the epoxy compounds include diglycidyl ether type epoxy compounds obtained by reaction of non-phenols and epichlorohydrin. As a specific example of the epoxy compound, 3,3 ', 5,5'-tetramethyl-4,4'-diglycidyloxybiphenyl (commercially available product "jER YX-4000" manufactured by Japan Epoxy Resin Co., (Epoxy equivalent: 180 to 192)) can be used.

Examples of the aromatic monocarboxylic acid include benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, cuminic acid, o-toluic acid, m-toluic acid, p- 4- (3-methylphenyl) benzoic acid, 4- (4-methylphenyl) benzoic acid, 4- (3,5-dihydroxybenzoic acid, Dimethylphenyl) benzoic acid, naphthoic acid, nicotinic acid, furo (2-methylphenyl) benzoic acid, 2-methyl-4-phenylbenzoic acid, 2,6- Acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, and the like. These aromatic monocarboxylic acids may be used alone or in combination of two or more.

In the above reaction, the epoxy group of the epoxy compound reacts with the carboxyl group of the aromatic monocarboxylic acid to synthesize the compound of the formula (1). Here, the reaction conditions are not particularly limited as long as the reaction proceeds. For example, the reaction temperature is 80 to 130 占 폚, more preferably 100 to 115 占 폚. The reaction time is preferably 10 to 25 hours. The mixing ratio (mixing ratio) of the epoxy compound and the aromatic monocarboxylic acid is not particularly limited as long as the reaction proceeds. For example, the number of moles of the epoxy group of the epoxy compound and the mole ratio of the aromatic monocarboxylic acid (number of moles of the epoxy group) / (number of moles of the aromatic monocarboxylic acid) is preferably in the range of 1 / 0.9 to 1.0.

In the above reaction, a catalyst may be used if necessary. Examples of the catalyst include phosphine compounds such as trimethylphosphine, triethylphosphine, tributylphosphine, trioctylphosphine and triphenylphosphine; Imidazole compounds such as 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-ethyl-4-methylimidazole and 4-phenyl-2-methylimidazole; Examples of the amines include triethylamine, tributylamine, trihexylamine, triamylamine, triethanolamine, dimethylaminoethanol, triethylenediamine, dimethylphenylamine, dimethylbenzylamine, 2- (dimethylaminomethyl) phenol, Amine compounds such as cyclo (5,4,0) undecene-7; And pyridine compounds such as dimethylaminopyridine. These catalysts are preferably used in an amount of 0.05 to 1 part by mass based on 100 parts by mass of the total amount of the epoxy compound and the aromatic monocarboxylic acid.

Among them, R ⁵ and R ⁶ are preferably an alkyl group or a glycidyl group having a hydroxyl group and an ester group as a substituent. In this case, X is more preferably -O-. As the compound of the formula (1), the compounds described in JP-A-2011-140637 and JP-A-2011-116912 are included in the compound of the formula (1). In addition, some of the compounds described in JP-A-2006-45468 are also included in the compounds of the formula (1). More specifically, more preferred examples of the compound of the formula (1) include the following. In addition, the compounds are defined by the following numbers. Namely, the compound of the following (1-1) is also referred to as "compound (1-1)".

The content of the retardation increasing agent in the cellulose ester film constituting the protective film B is not particularly limited and can be suitably adjusted to the content capable of achieving the value of the desired retardation which is exemplified in the following form. As an example, the content of the retardation-increasing agent in the cellulose ester film is preferably 0.5 to 30 parts by mass, more preferably 1 to 10 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester contained in the cellulose ester film, Particularly preferably 2 to 5 parts by mass. With such an amount, sufficient retardation can be imparted to the cellulose ester film. When the retardation increasing agent represented by the above formula (1) is used, it is possible to improve the tensile rupture strength of the film by adding the retardation increasing agent in such an amount, and furthermore, to reduce the volatility under high temperature and high humidity, It is possible to improve the sharpness of the image and further the image.

The retardation increasing agent may be added to the resin forming the cellulose ester film as a powder or may be added to the resin forming the cellulose ester film after being dissolved in a solvent.

(Plasticizer)

The cellulose ester film as the protective film B may contain a plasticizer in order to improve the fluidity of the composition at the time of film production, and the flexibility and processability of the film. Examples of the plasticizer include plasticizers such as a sugar ester plasticizer, a polyester plasticizer, a polyhydric alcohol ester plasticizer, an acrylic compound, a polycarboxylic acid ester plasticizer (including a phthalate ester plasticizer), a glycolate plasticizer, Ester plasticizers, fatty acid ester plasticizers, phosphoric acid ester plasticizers, and trimellitic acid ester plasticizers), styrene compounds, and the like. Among the plasticizers, those containing at least one plasticizer selected from the group consisting of the following ester ester plasticizers (sugar ester compounds), polyester plasticizers and acrylic compounds are preferable because they are effective in controlling the moisture permeability and compatibility with the cellulose ester at a high level It is preferable from the viewpoint of compatibility. These may be used alone or in combination of two or more.

The plasticizer preferably has a molecular weight of 5,000 or less, more preferably 3,000 or less, from the viewpoint of both improvement in wet heat resistance and compatibility with a cellulose ester. When the compound having a molecular weight of 3,000 or less is a polymer, the weight average molecular weight (Mw) is preferably 3,000 or less. The preferred range of molecular weight (Mw) is in the range of 100 to 2500, more preferably in the range of 300 to 2000.

The sugar ester plasticizer (sugar ester compound) refers to a compound having 1 to 12 furanose structures or pyranose structures, wherein all or part of the hydroxyl groups in the above compounds are esterified. The sugar ester plasticizer may be added for the purpose of hydrolysis prevention.

Examples of the sugar of the synthesis material of the sugar ester compound according to the present invention include, but are not limited to, the following. The present invention also relates to a pharmaceutical composition for preventing or treating diabetes mellitus such as glucose, galactose, mannose, fructose, xylose, or arabinose, lactose, sucrose, nisthos, 1F-fructosylnitose, stachyose, maltitol, lactitol, Maltose, celotriose, maltotriose, raffinose, or kestose. In addition, gentiobiose, gentiootriose, gentiotetraose, xylotriose, galactosyl sucrose and the like may be mentioned.

The monocarboxylic acid used for esterifying all or a part of the OH groups in the pyranose structure or the furanose structure is not particularly limited and includes aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, aromatic Monocarboxylic acid and the like can be used. The carboxylic acid used may be one type or a mixture of two or more types.

Examples of preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethylhexanecarboxylic acid, , Lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, , Saturated fatty acids such as montanic acid, melissic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linolic acid, linolenic acid, arachidonic acid and octetic acid.

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

Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids having 1 to 5 alkyl or alkoxy groups introduced into the benzene ring of benzoic acid such as benzoic acid, phenylacetic acid, and toluic acid, cinnamic acid, benzilic acid, biphenylcarboxylic acid , Naphthalenecarboxylic acid, tetralinecarboxylic acid, etc., or an aromatic monocarboxylic acid having two or more benzene rings, or derivatives thereof, and benzoic acid is particularly preferable.

Preferable examples of such sugar esters include sucrose esters represented by the following formula (FA).

R ₁ to R ₈ in the formula (FA) each independently represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group, or a substituted or unsubstituted arylcarbonyl group. R ₁ to R ₈ may be the same or different.

The substituted or unsubstituted alkylcarbonyl group is preferably a substituted or unsubstituted alkylcarbonyl group having 2 or more carbon atoms. Examples of the substituted or unsubstituted alkylcarbonyl group include a methylcarbonyl group (acetyl group). Examples of the substituent of the alkyl group include an aromatic hydrocarbon ring group such as a phenyl group.

The substituted or unsubstituted arylcarbonyl group is preferably a substituted or unsubstituted arylcarbonyl group having 7 or more carbon atoms. Examples of the arylcarbonyl group include a phenylcarbonyl group. Examples of the substituent of the aromatic hydrocarbon ring group include an alkyl group such as a methyl group, and an alkoxyl group such as a methoxy group.

The compound represented by the above formula (FA) has an average degree of substitution of preferably 3.0 to 8.0, more preferably 4.0 to 7.5, still more preferably 4.5 to 7.0, thereby controlling the moisture permeability and the cellulosic ester Can be highly compatible with each other.

In the present invention, the substitution degree of the compound represented by the formula (FA) represents the number of substituents other than hydrogen among the eight hydroxyl groups contained in the formula (FA), that is, R _{1 in the} formula (FA) of to R _8, it represents the number of groups containing other than hydrogen. Therefore, when all of R ₁ to R ₈ are substituted by substituents other than hydrogen, the degree of substitution is the maximum value of 8.0, and when all of R ₁ to R ₈ are hydrogen atoms, the degree of substitution is 0.0.

It is difficult to synthesize a compound having a structure represented by the chemical formula (FA) in which a number of hydroxyl groups and the number of OR groups are fixed, and it is difficult to synthesize a compound having a number of hydroxyl groups and OR groups (FA) in the present invention, it is preferable to use an average degree of substitution. The degree of substitution of the compound represented by the formula (FA) The average degree of substitution can be measured from the area ratio.

In the formula (FA), R ₁ to R ₈ represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted arylcarbonyl group, and R ₁ to R ₈ may be the same or different (hereinafter, R ₁ to R ₈ are also referred to as an acyl group). Specific examples of R ₁ to R ₈ include an acyl group derived from a monocarboxylic acid used in the synthesis of the sugar ester compound exemplified above.

Specific examples of the sugar ester compound according to the present invention include the case where any one of R ₁ to R ₈ is the same substituent R and the present invention is not limited thereto. In the following examples, polyester compounds are defined by the following symbols. In the present invention, R ₁ to R ₈ may be ester compounds each having a different group.

The sugar ester compound according to the present invention can be produced by reacting the above saccharide with an acylating agent (an acid halide such as acetyl chloride, an anhydride such as acetic anhydride, also referred to as an esterifying agent) The distribution is obtained by controlling the amount of the acylating agent, the timing of addition, and the esterification reaction time. However, by mixing the compounds having different degree of substitution with each other or the mixture of sugar ester compounds having different degrees of substitution, , And a degree of substitution of 4 or less can be adjusted.

(Synthesis Example: Synthesis Example of Diester Compound)

34.2 g (0.1 mol) of sucrose, 135.6 g (0.6 mol) of anhydrous benzoic acid, and 284.8 g (3.6 mol) of pyridine were fed into quaternary colbene equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introducing tube, The temperature was raised while nitrogen gas was bubbled through the nitrogen gas introducing tube, and the esterification reaction was carried out at 70 DEG C for 5 hours.

Subsequently, the internal pressure of the cholben was reduced to 4 × 10 ² Pa or less, excess pyridine was distilled off at 60 ° C., the internal pressure of the cholben was reduced to 1.3 × 10 ⁵ Pa or less, and the temperature was raised to 120 ° C. to obtain an anhydrous benzoic acid Was 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) 1, A-2, A-3, A-4 and A-5.

Analysis of the resulting mixture by high-performance liquid chromatography mass spectrometry (HPLC-MS) showed that 1.2 mass% of A-1, 13.2 mass% of A-2, 14.2 mass% of A-3, 35.4 mass% of A- , And A-5 and the like were 40.0% by mass. The average degree of substitution was 5.2.

Similarly, 158.2 g (0.70 moles), 146.9 g (0.65 moles), 135.6 g (0.60 moles) and 124.3 g (0.55 moles) of anhydrous benzoic acid were reacted with a sugar mole of pyridine to give a sugar ester Compound.

Subsequently, a part of the obtained mixture was purified by column chromatography using silica gel to obtain A-1, A-2, A-3, A-4 and A-5 with a purity of 100%.

In addition, A-5 and the like mean a mixture of all components having a degree of substitution of 4 or less, that is, a compound of substitution degree 4, 3, 2 or 1. The average degree of substitution was calculated as A-5, etc. as the degree of substitution 4.

In the present invention, average degree of substitution was adjusted by adding the sugar ester and the isolated A-1 to A-5, etc. close to the desired degree of substitution desired by the method produced here.

Examples of other sugar esters include the compounds described in JP-A-62-42996 and JP-A-10-237084.

The polyester plasticizer is not particularly limited. For example, a polyester (plasticizer) obtained by condensation reaction of a dicarboxylic acid or an ester-forming derivative thereof with a glycol and having a terminal hydroxyl group (hydroxyl group) Polyol), or a polymer (terminal-sealed polyester) in which the terminal hydroxyl group of the polyester polyol is sealed with a monocarboxylic acid. The ester-forming derivatives referred to herein are esters of dicarboxylic acids, dicarboxylic acid chlorides, and anhydrides of dicarboxylic acids.

Preferably, it is preferable to use a polyester plasticizer represented by the following formula (FB-1) from the viewpoint of highly compatibility with the control of the moisture permeability and compatibility with the cellulose ester.

Wherein A represents an aromatic ring group having 6 to 14 carbon atoms or an aliphatic group having 4 to 12 carbon atoms and n is an integer of 1 or more Represents a natural number.

The compound represented by the above formula is obtained from a dicarboxylic acid having an aromatic ring (also referred to as an aromatic dicarboxylic acid) and a straight chain or branched alkylene or cycloalkylene diol having 2 to 6 carbon atoms, Is not sealed with a monocarboxylic acid.

Examples of the aromatic dicarboxylic acid having 6 to 16 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, Naphthalene dicarboxylic acid, 2,2'-biphenyl dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyl dicarboxylic acid, And the like. Among them, phthalic acid and terephthalic acid are preferable.

Examples of the aromatic dicarboxylic acid having 4 to 12 carbon atoms include 1,2-ethanedicarboxylic acid (succinic acid), 1,3-propanedicarboxylic acid (glutaric acid), 1,4-butanedicarboxylic acid (Adipic acid), 1,5-pentanedicarboxylic acid (pimelic acid), and 1,8-octanedicarboxylic acid (sebacic acid). Adipic acid and succinic acid are particularly preferable.

Further, the dicarboxylic acid is preferably mixed with an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid in view of improvement of film strength.

Examples of the straight chain or branched alkylene or cycloalkylene diol having 2 to 6 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3- 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4- 4-cyclohexane dimethanol, and the like. Among them, ethanediol, 1,2-propanediol, 1,3-propanediol and 1,3-butanediol are preferable.

Among them, it is preferable that A is a naphthalene ring or biphenyl ring which may have a substituent in order to obtain the effect of the present invention. Here, the substituent is an alkyl group, alkenyl group, or alkoxyl group having 1 to 6 carbon atoms.

The hydroxyl value (OH value) of the polyester compound is preferably 100 mgKOH / g or more and 500 mgKOH / g or less, and more preferably 170 mgKOH / g to 400 mgKOH / g. When the hydroxyl value is in this range, the compatibility with the cellulose ester and the cellulose ether becomes suitable.

If the hydroxyl value is 400 mgKOH / g or less, the hydrophobicity of the polyester compound is not excessively increased, and if the hydroxyl value is 170 mgKOH / g or more, the intermolecular interaction (hydrogen bond, etc.) between the polyester compounds is not excessively strengthened, It is possible to prevent the precipitation of

The hydroxyl value can be measured by an acetic anhydride method described in Japanese Industrial Standard JIS K1557-1: 2007.

The number average molecular weight (Mn) of the polyester compound can be calculated by the following formula.

The polyester compound can be produced by a conventional method such as a thermal melt condensation method by a polyesterification reaction or an ester exchange reaction of a dicarboxylic acid and a diol or an interfacial condensation method of an acid chloride and a glycol Can be easily synthesized by any method.

The polyester compound is exemplified below.

Preferably, it is preferable to use a polyester plasticizer represented by the following formula (FB-2) from the viewpoint of highly compatibility with the control of the moisture permeability and compatibility with the cellulose ester.

In the above formula (FB-2), B represents a hydroxyl group or a carboxylic acid residue, G represents an alkylene glycol residue having 2 to 18 carbon atoms or an aryl glycol residue having 6 to 12 carbon atoms or an oxyalkylene A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.

In the formula (FB-2), a hydroxy group or a carboxylic acid residue represented by B, an alkylene glycol residue or an oxyalkylene glycol residue or an aryl glycol residue represented by G, an alkylene dicarboxylic acid residue represented by A Or an aryl dicarboxylic acid residue, and is obtained by a reaction similar to that of a common ester compound.

Examples of the carboxylic acid component of the polyester-based compound represented by the formula (FB-2) include acetic acid, propionic acid, butyric acid, benzoic acid, para tert-butylbenzoic acid, orthotoluic acid, Benzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, aliphatic acid and the like, and these can be used individually or as a mixture of two or more kinds.

Examples of the alkylene glycol component having 2 to 18 carbon atoms in the polyester compound represented by the formula (FB-2) include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, Propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2- Glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylol pentane), 2-n-butyl- Methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, , Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like, and these glycols are used as one kind or as a mixture of two or more kinds.

Particularly preferred are alkylene glycols having 2 to 12 carbon atoms because they are excellent in compatibility with cellulose ester resins. More preferably an alkylene glycol having 2 to 6 carbon atoms, and still more preferably an alkylene glycol having 2 to 4 carbon atoms.

Examples of the aryl glycol having 6 to 12 carbon atoms in the polyester plasticizer represented by the formula (FB-2) include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, cyclohexane diethanol, Benzene dimethanol, etc. These glycols can be used singly or as a mixture of two or more kinds.

Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms in the polyester compound represented by the above formula (FB-2) include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene Glycol, etc. These glycols can be used singly or as a mixture of two or more kinds.

Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms in the polyester compound represented by the formula (FB-2) include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, Maleic acid, maleic acid, dodecanedicarboxylic acid, and the like, and these are used as one kind or a mixture of two or more kinds.

Examples of the aryl dicarboxylic acid component having 6 to 12 carbon atoms in the polyester-based compound represented by the formula (FB-2) include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, And the like.

The polyester-based compound represented by the formula (FB-2) preferably has a weight average molecular weight of preferably 300 to 3000, more preferably 350 to 1500. The acid value is not more than 0.5 mgKOH / g, the hydroxyl group (hydroxyl group) is not more than 25 mgKOH / g, more preferably the acid value is not more than 0.3 mgKOH / g, and the hydroxyl group (hydroxyl group) is not more than 15 mgKOH / g.

The weight average molecular weight of the polyester plasticizer is calculated by measurement using gel permeation chromatography (GPC) under the following measurement conditions.

Specific compounds of the polyester-based compounds represented by the formula (FB-2) which can be used in the present invention are shown below, but the present invention is not limited thereto. In the following examples, the polyester-based compounds are defined by the following symbols.

The viscosity of the polyester plasticizer varies depending on the molecular structure and the molecular weight. However, in the case of the adipic acid plasticizer, compatibility with the cellulose ester is high and the effect of imparting plasticity is high, and the viscosity of the plasticizer is from 200 to 5000 mPa · s ( 25 < 0 > C). The polyester-based plasticizer may be used in one kind or two or more kinds in combination.

The polyhydric alcohol ester plasticizer is an ester compound (alcohol ester) of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and is preferably an aliphatic polyhydric alcohol ester of 2 to 20 equivalents. The polyhydric alcohol ester compound preferably has an aromatic ring or a cycloalkyl ring in the molecule.

The acrylic compound is not particularly limited, but is preferably at least one acrylic monomer selected from the group consisting of (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamides, and (meth) acrylonitrile Of repeating units. These acrylic compounds can improve the water resistance of the film.

Among them, the acrylic compound preferably contains 50 to 99 mass% of methyl methacrylate units and 1 to 50 mass% of other monomer units copolymerizable therewith.

Other copolymerizable monomers include alkyl methacrylates having 2 to 18 carbon atoms in the alkyl group; Alkyl acrylates having 1 to 18 carbon atoms in the alkyl group; Vinyl monomers having an amide group such as acryloylmorpholine and N, N-dimethylacrylamide; A methacrylic acid ester or an acrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the ester moiety; ?,? - unsaturated carboxylic acids such as acrylic acid and methacrylic acid; Unsaturated carboxylic acid containing unsaturated groups such as maleic acid, fumaric acid and itaconic acid; Aromatic vinyl compounds such as styrene and? -Methylstyrene; ?,? - unsaturated nitriles such as acrylonitrile and methacrylonitrile; Maleic anhydride, maleimide, N-substituted maleimide, and anhydrous glutaric acid. These may be used alone or in combination of two or more kinds of monomers.

The acrylic compound used in the present invention may have a cyclic structure, and specifically includes a lactone ring structure, an anhydroglutaric acid structure, a glutarimide structure, an N-substituted maleimide structure and a maleic anhydride structure, Ring structure.

Among these, from the viewpoints of thermal decomposition resistance and fluidity of the copolymer, the other copolymerizable monomer is preferably an alkyl acrylate having an alkyl group of 1 to 18 carbon atoms, a vinyl monomer having an amide group such as acryloylmorpholine or dimethyl acrylamide, Methacrylic acid ester or acrylic acid ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms, an N-substituted maleimide structure, a pyran ring structure and the like are preferable.

Specific examples of the alkyl acrylate having 1 to 18 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate and 2-ethylhexyl acrylate. , And preferably methyl acrylate.

Specific examples of the vinyl monomer having an amide group include acrylamide, N-methylacrylamide, N-butyl acrylamide, N, N-dimethyl acrylamide, N, N-diethylacrylamide, acryloylmorpholine, Acrylamide, N-methylmethacrylamide, N-butylmethacrylamide, N, N-dimethylmethacrylamide, N, N-diethyl Methacrylamide, methacryloylmorpholine, N-hydroxyethylmethacrylamide, methacryloylpyrrolidine, methacryloylpiperidine, N-vinylformamide, N-vinylacetamide, vinylpyrrolidone And the like. Preferred are acryloylmorpholine, N, N-dimethylacrylamide, N-butyl acrylamide, vinylpyrrolidone and 2-hydroxyethyl methacrylate.

Specific examples of the methacrylic ester or acrylic ester having an alicyclic hydrocarbon group having 5 to 22 carbon atoms in the ester moiety include cyclopentyl acrylate, cyclohexyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, norbornyl acrylate, Acrylate, norbornyl acrylate, cyanonorbornyl acrylate, isobornyl acrylate, boron acrylate, menthyl acrylate, pentyl acrylate, adamantyl acrylate, dimethyladamantyl acrylate, acrylic acid tricyclo [5.2.1.0 ^2,6 ] Decyl-8-yl, acrylic acid tricyclo [5.2.1.0 ^2,6 ] deca-4-methyl, cyclodecyl acrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, methylcyclohexyl methacrylate, trimethyl methacrylate Cyclohexyl methacrylate, norbornyl methacrylate, norbornyl methacrylate, cyanonorbornyl methacrylate, meta Acrylonitrile, acrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, methacrylonitrile, [5.2.1.0 ^2,6 ] deca-8-yl, methacrylic acid tricyclo [5.2.1.0 ^2,6 ] deca-4-methyl, methacrylic acid cyclodecyl methacrylate, dicyclopentanyl methacrylate and the like .

Preferred are isobornyl methacrylate, dicyclopentanyl methacrylate, dimethyl adamantyl methacrylate, and the like.

Examples of the N-substituted maleimide include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, Ni-propylmaleimide, N-butylmaleimide, Maleimide, N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, N- (2-chlorophenyl) maleimide, N- (2-ethylphenyl) maleimide, N- (2-methoxyphenyl) maleimide, N- (2-methylphenyl) maleimide, N- (4,6-trimethylphenyl) maleimide, N- (4-benzylphenyl) maleimide and N- (2,4,6-tribromophenyl) maleimide. Maleimide, N-cyclohexylmaleimide, and N-phenylmaleimide.

These monomers may be those commercially available.

The acrylic compound preferably has a weight average molecular weight (Mw) in a range of 15000 or less, more preferably 10,000 or less, more preferably 10000 or less, from the viewpoint of achieving compatibility between the moisture permeability control and compatibility with the cellulose ester Is in the range of 5,000 to 10,000. The weight average molecular weight (Mw) of the acrylic compound according to the present invention is calculated by measurement using gel permeation chromatography (GPC) under the following measurement conditions.

Examples of aliphatic polyhydric alcohols include ethylene glycol, propylene glycol, trimethylol propane, pentaerythritol and the like.

The monocarboxylic acid may be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like. The monocarboxylic acid may be used in one kind or in a mixture of two or more kinds. Further, all of the OH groups contained in the aliphatic polyhydric alcohol may be esterified, or some of them may be left as OH groups.

The aliphatic monocarboxylic acid is preferably a linear or branched chain fatty acid having 1 to 32 carbon atoms. The carbon number of the aliphatic monocarboxylic acid is more preferably 1 to 20, and still more preferably 1 to 10. Examples of such aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid and the like, and in order to enhance compatibility with the cellulose ester, acetic acid may be preferably used.

Examples of the alicyclic monocarboxylic acid include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid and the like.

Examples of aromatic monocarboxylic acids include benzoic acid; Those in which 1 to 3 alkyl or alkoxy groups (e.g., methoxy or ethoxy) are introduced into the benzene ring of benzoic acid (e.g., toluic acid); Aromatic monocarboxylic acids having two or more benzene rings (for example, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralinecarboxylic acid, etc.), and preferably benzoic acid.

The molecular weight of the polyhydric alcohol ester plasticizer is not particularly limited, but is preferably within the range of 300 to 1500, and more preferably within the range of 350 to 750. In order to make it difficult to be volatilized, it is preferable that the molecular weight is large. In order to increase the moisture permeability and improve the compatibility with the cellulose ester, the molecular weight is preferably small.

Specific examples of polyhydric alcohol ester plasticizers include trimethylolpropane triacetate, trimethylolpropane benzoic acid ester, pentaerythritol tetraacetate, ester compound (A) represented by the formula (I) described in Japanese Patent Application Laid-Open No. 2008-88292, And the like.

The polybasic carboxylic acid ester plasticizer is an ester compound of a polyvalent carboxylic acid having 2 or more valences, preferably 2 to 20 valences, with an alcohol compound. The polycarboxylic acid is preferably an aliphatic polycarboxylic acid having 2 to 20 carbon atoms, an aromatic polycarboxylic acid having 3 to 20 carbon atoms, or an alicyclic polycarboxylic acid having 3 to 20 carbon atoms.

Examples of the polyvalent carboxylic acid include trivalent or higher aromatic polycarboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid or derivatives thereof; Aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid, and tetrahydrophthalic acid; Oxydarboxylic acids such as tartaric acid, tartronic acid, malic acid and citric acid, and oxydicarboxylic acids are preferable for inhibiting volatilization from the film.

Examples of the alcohol compound include an aliphatic saturated alcohol compound having a straight chain or a side chain, an aliphatic unsaturated alcohol compound having a straight chain or side chain, an alicyclic alcohol compound, or an aromatic alcohol compound. The number of carbon atoms of the aliphatic saturated alcohol compound or aliphatic unsaturated alcohol compound is preferably 1 to 32, more preferably 1 to 20, and still more preferably 1 to 10. Examples of the alicyclic alcohol compound include cyclopentanol, cyclohexanol, and the like. Examples of the aromatic alcohol compound include phenol, para-cresol, dimethyl phenol, benzyl alcohol, cinnamyl alcohol and the like. The alcohol compound may be one kind or a mixture of two or more kinds.

The molecular weight of the polycarboxylic acid ester plasticizer is not particularly limited, but is preferably within the range of 300 to 1000, and more preferably within the range of 350 to 750. The molecular weight of the polycarboxylic acid ester plasticizer is preferably large in view of suppressing bleed-out. From the viewpoint of the moisture permeability and compatibility with the cellulose ester, a smaller size is preferable.

The acid value of the polycarboxylic acid ester plasticizer is preferably 1 mgKOH / g or less, more preferably 0.2 mgKOH / g or less. Refers to the number of milligrams of potassium hydroxide required to neutralize the acid (the carboxyl group present in the sample) contained in 1 g of the sample. The acid value is measured in accordance with JIS K0070 (1992).

Examples of the polycarboxylic acid ester plasticizers include ester compounds (B) represented by the formula (II) described in JP-A-2008-88292.

The polycarboxylic acid ester plasticizer may be a phthalic acid ester plasticizer. Examples of phthalate ester plasticizers include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dicyclohexyl phthalate, dicyclohexylterephthalate and the like .

Examples of glycolate-based plasticizers include alkyl phthalyl alkyl glycolates. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate and the like.

Ester plasticizers include fatty ester plasticizers, citric ester plasticizers, phosphoric acid ester plasticizers, and trimellitic acid plasticizers.

Examples of the fatty acid ester plasticizers include butyl oleate, methyl acetyl ricinolate, dibutyl sebacate, and the like. Examples of the citrate ester plasticizer include acetyltrimethyl citrate, acetyltriethyl citrate, acetyl tributyl citrate, and the like. Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl phosphate, diphenyl biphenyl phosphate (BDP), trioctyl phosphate, tributyl phosphate and the like. Examples of the trimellitic acid-based plasticizers include octyl trimellitate, n-octyl trimellitate, isodecyl trimellitate, isononyl trimellitate and the like.

The styrene-based compound (styrene-based plasticizer) may be a homopolymer of a styrene-based monomer, or may be a copolymer of a styrene-based monomer and other copolymerizable monomers. The content ratio of the styrene-based monomer-derived constitutional unit in the styrene-based compound is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, in order for the molecular structure to have a certain volume or more.

The styrene-based monomer is preferably a compound represented by the following formula (A).

R ¹⁰¹ to R ¹⁰³ in the formula (A) each independently represent a hydrogen atom or an alkyl group or an aryl group having 1 to 30 carbon atoms. R ¹⁰⁴ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group, an aryl group, an alkoxy group having 1 to 30 carbon atoms, an aryloxy group, an alkyloxycarbonyl group having 2 to 30 carbon atoms, an aryloxycarbonyl group, An alkylcarbonyloxy group, an arylcarbonyloxy group, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an amide group and a nitro group. Each of these groups may further have a substituent (for example, a hydroxyl group, a halogen atom, an alkyl group, etc.). R ¹⁰⁴ may be the same or different and may be bonded to each other to form a ring.

Examples of the styrene-based monomer include styrene; alkyl-substituted styrenes such as? -methylstyrene,? -methylstyrene and p-methylstyrene; Halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrenes such as p-hydroxystyrene,? -methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene and 3,4-dihydroxystyrene; Vinylbenzyl alcohols; alkoxy-substituted styrenes such as p-methoxystyrene, p-tert-butoxystyrene and m-tert-butoxystyrene; Vinylbenzoic acids such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; Amide styrenes such as 2-butyl amide styrene, 4-methyl amide styrene and p-sulfonamide styrene; Aminostyrenes such as 3-aminostyrene, 4-aminostyrene, 2-isopropenyl aniline and vinyl benzyl dimethyl amine; Nitrostyrenes such as 3-nitrostyrene and 4-nitrostyrene; Cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene; Vinylphenylacetonitrile; Aryl styrenes such as phenylstyrene, and indenes. The styrene-based monomer may be used in one kind or in a combination of two or more kinds.

The copolymerizable monomer to be combined with the styrene-based monomer is a (meth) acrylic acid ester compound represented by the following formula (B), maleic anhydride, citraconic anhydride, cis-1-cyclohexene-1,2-anhydrous dicarboxylic acid , 3-methyl-cis-1-cyclohexene-1,2-anhydro dicarboxylic acid and 4-methyl-cis-1-cyclohexene-1,2-anhydrous dicarboxylic acid, acrylonitrile , Nitrile group-containing radically polymerizable monomers such as methacrylonitrile; Amide bond-containing radically polymerizable monomers such as acrylamide, methacrylamide, and trifluoromethanesulfonylaminoethyl (meth) acrylate; Fatty acid vils such as vinyl acetate; Chlorine-containing radically polymerizable monomers such as vinyl chloride and vinylidene chloride; And conjugated diolefins such as 1,3-butadiene, isoprene and 1,4-dimethylbutadiene. The (meth) acrylic acid ester compound represented by the following formula (B) or maleic anhydride is preferable.

R ¹⁰⁵ to R ¹⁰⁷ in the formula (B) each independently represent a hydrogen atom or an alkyl group or an aryl group having 1 to 30 carbon atoms. R ¹⁰⁸ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group or an aryl group. Each of these groups may further have a substituent (for example, a hydroxyl group, a halogen atom, an alkyl group, etc.).

Examples of the (meth) acrylate compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n- (tert-), pentyl (meth) acrylate (n-, i-, s-), hexyl (meth) acrylate, n- (N-, i-), (meth) nonyl acrylate (n-, i-), myristyl (meth) acrylate (n-, i-), (meth) (Meth) acrylic acid (2-hydroxypropyl), (meth) acrylic acid (3-hydroxypropyl), (meth) acrylic acid (Meth) acrylic acid (2-methoxyethyl), (meth) acrylic acid (2-ethoxyethyl) acrylate, Acrylic acid (2 or 4-chlorophenyl), (meth) acrylic acid (2 or 3 or 4-ethoxycarbonylphenyl), (meth) (Meth) acrylate, phenethyl (meth) acrylate, phenethyl (meth) acrylate, 2-naphthyl (meth) acrylate, cyclohexyl Cyclohexyl), (meth) acrylic acid (4-ethylcyclohexyl), and the like.

Specific examples of the styrene-based compound include styrene / maleic anhydride copolymer, styrene / acrylic acid ester copolymer, styrene / hydroxystyrene polymer, styrene / acetoxystyrene polymer and the like. Among them, a styrene / maleic anhydride copolymer is preferable.

The content of the plasticizer is not particularly limited, but is preferably in the range of 0.1 to 30 mass%, more preferably in the range of 5 to 20 mass%, based on 100 mass% of the cellulose ester contained in the cellulose ester film. With such an amount, it is difficult for the cellulose ester film to generate bleed-out.

(Other additives)

Further, the retardation film of the present invention may further include other additives, if necessary, in place of or in addition to the plasticizer. Examples of such other additives include, but are not limited to, hydrogen bonding compounds, activators, antioxidants, colorants, ultraviolet absorbers, matting agents, acrylic particles, hydrogen bonding solvents, and ionic surfactants.

The hydrogen-bonding compound can reduce the variation of the retardation value Rt with respect to the change of humidity. The hydrogen-bonding compound preferably has at least a functional group selected from a hydroxyl group, an amino group, a thiol group, and a carboxylic acid group in one molecule, more preferably has a plurality of different functional groups in one molecule, It is particularly preferable to have a hydroxy group and a carboxylic acid group.

The hydrogen-bonding compound preferably contains 1 to 2 aromatic rings as the parent nucleus, and it is preferable that the value obtained by dividing the number of the functional groups contained in one molecule by the molecular weight of the compound is 0.01 or more.

The effect is that the hydrogen bonding compound binds (hydrogen bonds) to a site where the cellulose ester interacts with water molecules (hydrogen bonding) and functions to suppress the change in charge distribution due to desorption of water molecules Respectively.

Exemplary compounds include Exemplary Compound E-104 described in JP-A-2012-82235.

The hydrogen-bonding compound may be added in an amount of 1 to 30 parts by mass based on 100 parts by mass of the cellulose ester.

The film of the present invention is preferably used on the viewer side or the backlight side of the polarizing plate, and it is preferable that the film contains an ultraviolet absorber for the purpose of imparting an ultraviolet ray absorbing function. The ultraviolet absorber is not particularly limited, and the ultraviolet absorber described above may be used as the ultraviolet absorber that can be included in the polyester film as the protective film A.

The amount of the ultraviolet absorber to be used in the cellulose ester film as the protective film B is not uniform depending on the kind of the ultraviolet absorber and the conditions of use but is generally from 0.05 to 10% by mass, preferably from 0.05 to 10% by mass based on 100% by mass of the cellulose ester. Preferably in the range of 0.1 to 5 mass%.

The matting agent is a fine particle which imparts slipperiness of the film and does not impair the transparency of the resulting film and may be either an inorganic compound or an organic compound if it has heat resistance at the time of melting. These matting agents may be used alone or in combination of two or more. By using particles having different particle sizes or shapes (for example, needle shape and spherical shape), it is possible to achieve both high transparency and slidability. Of these, silicon dioxide having excellent transparency (haze) is particularly preferably used since the refractive index is close to that of the acrylic copolymer or the cellulose ester used as the compatibilizing resin.

Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., (Manufactured by Nippon Silicas Co., Ltd.), Sephosta KEP-30, Sephosta KEP-50 (manufactured by Nippon Sanskubai Co., Ltd.), Sirohobik 100 (manufactured by Fuji Silica), Nipshil E220A Tex), and the like can be preferably used.

The shape of the particles can be arbitrarily used, such as irregular shape, needle shape, flattened shape, spherical shape, and the like, but spherical particles are particularly preferable because transparency of the obtained film is good.

The particle size is preferably smaller than the wavelength of visible light, and is preferably not more than 1/2 of the wavelength of visible light, since light is scattered when the wavelength is close to the wavelength of visible light and transparency deteriorates. When the particle size is too small, the slidability may not be improved, so that it is particularly preferable that the particle size is in the range of 80 nm to 180 nm. The particle size means the size of the aggregate when the particles are aggregates of primary particles. When the particle is not spherical, it means the diameter of the circle corresponding to the projected area.

The matting agent is preferably added in an amount of 0.05 to 10 mass%, preferably 0.1 to 5 mass%, based on the resin (cellulose ester).

The film of the present invention may contain acrylic particles described in, for example, International Publication WO 2010/001668 pamphlet in an amount that can maintain transparency. The acrylic particles serve to improve the brittleness of the film.

Examples of commercially available acrylic particles include commercially available products such as " Metablen W-341 " manufactured by Mitsubishi Rayon Co., Ltd., " Kanease " manufactured by Kaneka Corporation, " Paraloid " manufactured by Kuraray Co., L-Lloyd ", " Starfilloy ", KEMISONOU MR-2G, MS-300X manufactured by Kanto Kasei Kogyo Co., Ltd., and PARAPET SA available from Kuraray Co., , Which may be used alone or in combination of two or more.

The hydrogen-bonding solvent may be added for the purpose of adjusting (reducing) the solution viscosity to a solvent for dissolving the constituent material of the film when the film is produced by the solution casting method. Hydrogen-binding solvent refers to an electrically negatively charged atom (oxygen, nitrogen, fluorine, and nitrogen) as described in JN Israel Artibiller, Molecular Force and Surface Force (Kondo Damosu, Oshima Hiroyuki translation, McGraw Hill publication, , An organic solvent capable of generating a hydrogen atom-mediated "bond", that is, a bond having a large bonding moment and occurring in a hydrogen-containing bond, which is generated between an electrically negatively atom and a covalently bonded hydrogen atom, Refers to an organic solvent capable of arranging molecules in close proximity by including OH (oxygen-hydrogen bond), NH (hydrogen-nitrogen bond), and FH (fluorohydrogen bond).

They expect a change in solution viscosity by forming a strong hydrogen bond between the resin and the hydrogen-bonding solvent rather than the intermolecular hydrogen bond of the acrylic copolymer, the cellulose ester resin, or a mixture of other resins for commercialization .

In the solution casting method performed in the present invention, for the purpose of lowering the peeling force at the time of film formation, besides adjusting the solution viscosity of the resin solution to be used, The whole amount can be used.

The ionic surfactant may be added for the purpose of lowering the peeling force at the time of film formation.

Examples of the ionic surfactant usable in the present invention include cationic surfactants, anionic surfactants, and amphoteric surfactants.

Examples of the cationic surfactant include an aliphatic amine salt, an aliphatic quaternary ammonium salt, a benzalkonium salt, a benzethonium chloride, a pyridinium salt, and an imidazolinium salt.

Examples of the anionic surfactant include higher alcohol (C ₈ to C ₂₂ ) sulfuric acid ester salts (for example, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, (For example, sodium salt of cetyl alcohol phosphate ester), alkylarylsulfonic acid salts (for example, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, Sodium salt of dinaphthalene disulfonic acid, sodium salt of meta-nitrobenzenesulfonic acid, etc.), sulfonic acid salts of alkyl amides (for example, C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ SO ₃ Na), sulfonic acid salts of dibasic fatty acid esters (for example, dioctyl sodium sulfosuccinate and dihexyl sodium sulfosuccinate). Of these, sulfuric acid salts and sulfonic acid salts are suitably used.

Examples of the amphoteric surfactant include carboxybetaine, sulfobetaine, aminocarboxylate, imidazolinium betaine and the like.

Among them, anionic surfactants are preferred in the present invention. The surfactant is used in an amount of 0.01 to 5% by mass, preferably 0.05 to 3% by mass, more preferably 0.2 to 2% by mass, based on the total amount of the resin constituting the film Is preferably used. When the amount is larger than this range, the surfactant is precipitated from the film, the hygroscopicity of the film is increased, and an undesirable quality is exhibited in the quality of the retardation film. If the addition amount is smaller than this range, the effect of the present invention using a surfactant may not be obtained.

(Physical Properties of Film)

Hereinafter, the characteristics of the cellulose ester film as the protective film B in the present invention will be described.

(Transparency)

The haze value (turbidity) is used as an index for judging the transparency of the cellulose ester film. Particularly in a liquid crystal display device used outdoors, since it is required to obtain a sufficient luminance and a high contrast even in a bright place, the haze value is preferably 0.6% or less, more preferably 0.4% or less. When used as a scattering film, the haze value may exceed the above range. The internal haze of the film is preferably 0.01 to 0.1.

The film of the present invention preferably has a total light transmittance of 90% or more, and more preferably 93% or more. The practical upper limit is about 99%.

The haze value and transmittance can be measured using a haze meter.

The film satisfying the above physical properties can be preferably used also as a polarizing plate protective film for a liquid crystal display device of a large size or a liquid crystal display device for outdoor use.

(Retardation)

The retardation value in the in-plane direction defined by the following formulas (i) and (ii) is in the range of 30 to 70 nm, The retardation value Rt in the thickness direction is preferably in the range of 100 to 140 nm from the viewpoint of improving the contrast and viewing angle upon mounting the VA type display device. Particularly, when the retardation value Ro in the in-plane direction is in the range of 45 to 60 nm and the retardation value Rt in the thickness direction is in the range of 110 to 135 nm, the contrast and viewing angle upon mounting the VA- .

Formula (i): Ro = (n x -n y) × d (㎚)

Formula (ii): Rt = {( n x + n y) / 2-n z} × d (㎚)

In the formulas (i) and (ii), n _x represents the refractive index in the direction x at which the refractive index becomes maximum in the in-plane direction of the film. n _y represents the refractive index in the direction y perpendicular to the direction x in the in-plane direction of the film. and n _z represents the refractive index in the thickness direction z of the film. and d represents the thickness (nm) of the film. The measurement is performed at a measurement wavelength of 590 nm in an environment of 23 캜, 55% RH.

(Production method of cellulose ester film)

Next, a method for producing a cellulose ester film will be described. The present invention is not limited to this.

As a production method of the cellulose ester film, a production method such as a general inflation method, a T-die method, a calendering method, a cutting method, a soft method, an emulsion method and a hot press method can be used. From the viewpoint of suppression of optical defects such as lines, etc., the solution casting method and the melt casting method are preferable, and in particular, the solution casting method is more preferable for obtaining a uniform surface.

≪ Solution flexible film-forming method &

When a film is formed by a solution casting method, a method for producing a cellulose ester film includes a step of dissolving a cellulose ester and a desired additive in a solvent to prepare a dope (a dissolution step; a dope producing step), an infinite metal support (Stretching process), a process of drying a flexible dope as a web (solvent evaporation process), a process of peeling off a metal support (a peeling process), a process of drying, stretching and maintaining a width And a step of winding the finished film (winding step).

Fig. 2 is a diagram schematically showing an example of a dope manufacturing process, a softening process and a drying process (solvent evaporation process) of a solution casting film forming method preferable for the present invention.

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

Thereafter, the main dope is filtered in the main filter (3), and the additive additive liquid is added inline from 16. In many cases, the main dope may contain about 10 to 50 mass% of recovered scrap. The recovered scrap is a finely pulverized film. A film fabric produced by cutting out both side portions of the film or speckled out, which is generated when a film is formed, is used.

As the raw material for the resin used in the preparation of the dope, a cellulose ester and a desired additive or the like may be pelletized in advance.

Hereinafter, each process will be described.

1) Dissolution Process (Doping Process)

This step is a step of dissolving the cellulose ester and a desired additive in a solvent mainly containing a good solvent for the cellulose ester in a dissolving oven while stirring to form a dope.

The concentration of the cellulose ester in the dope is preferable because it can reduce the drying load after the cellulose ester is softened on the metal support. However, if the concentration of the cellulose ester is too high, the load during filtration increases and the filtration accuracy deteriorates. The concentration compatible therewith is preferably 10 to 35 mass%, and more preferably 15 to 22 mass%.

The solvent used in the dope may be used alone or in combination of two or more kinds. However, it is preferable to mix a good solvent of the cellulose ester and a poor solvent in view of production efficiency, and the cellulose ester It is preferable from the viewpoint of solubility.

A preferable range of the mixing ratio of the good solvent and the poor solvent is that the two solvents are 70 to 98 mass% and the poor solvent is 2 to 30 mass%. The positive solvent and the poor solvent are defined as poor solvents in which the cellulose ester to be used alone is dissolved in a good solvent, and those in which the cellulose ester alone is not swollen or dissolved. As a result, the average degree of substitution of the cellulose ester changes both the good solvent and the poor solvent.

The two solvents to be used in the present invention are not particularly limited, but organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate and the like can be given. Particularly preferred are methylene chloride or methyl acetate.

The poor solvent used in the present invention is not particularly limited, and for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used. It is preferable that the dope contains 0.01 to 2% by mass of water.

The solvent used for dissolving the cellulose ester is used by recovering the solvent removed from the film by drying in the film-forming step, and reusing the solvent.

In the recovery solvent, a small amount of an additive added to cellulose acetate, for example, a plasticizer, an ultraviolet absorber, a polymer, a monomer component and the like may be contained. However, even if they are contained, they can be preferably reused, It is possible.

As the dissolution method of the cellulose ester in the preparation of the above-described dope, a general method can be used. Specifically, there are a method of carrying out at normal pressure, a method of carrying out at a pressure not higher than the boiling point of the main solvent, a method of carrying out pressurization at a boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557 Various methods such as a method of carrying out by a cooling dissolution method as disclosed in JP-A-9-95538 and a method of carrying out at a high pressure as disclosed in JP-A-11-21379 can be used. Among them, a method of performing pressurization at a boiling point or higher of the main solvent is preferable, and heating and pressurization can be combined to heat at a boiling point or more at normal pressure.

Also, a method of stirring and dissolving while heating at a temperature higher than the boiling point of the solvent at normal pressure and at a temperature in which the solvent does not boil under pressure is also preferable because it prevents the formation of a massive undissolved product called a gel or agglomerate.

Further, a method of mixing cellulose acetate with a poor solvent to wet or swell the cellulose acetate, and further adding a two-component agent to dissolve the cellulose acetate is also preferably used.

The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of raising the vapor pressure of the solvent by heating. The heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.

The heating temperature to which the solvent is added is preferably from the viewpoint of the solubility of the cellulose acetate, but if the heating temperature is too high, the pressure required becomes large and the productivity is deteriorated.

The preferred heating temperature is 45 to 120 占 폚, more preferably 60 to 110 占 폚, and even more preferably 70 to 105 占 폚. Also, the pressure is adjusted so that the solvent does not boil at the set temperature.

Or a cooling dissolution method is preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

Next, it is preferable to filter the cellulose ester solution (dope after dissolution or after dissolution) using a suitable filter material such as filter paper.

As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insolubles and the like. However, if the absolute filtration accuracy is too small, there is a problem that clogging of the filter medium is liable to occur. For this reason, a filter material having an absolute filtration accuracy of 0.008 mm or less is preferable, a filter material of 0.001 to 0.008 mm is more preferable, and a filter material of 0.003 to 0.007 mm is more preferable.

The material of the filter medium is not particularly limited and a normal filter material can be used. However, a plastic filter material such as polypropylene or Teflon (registered trademark) or a metal filter material such as stainless steel is preferable because the fiber does not fall off.

It is preferable to remove and reduce impurities, particularly bright foreign matter, contained in the cellulose acetate of the raw material by filtration.

A spot of foreign matter means a two-piece polarizer arranged in a cross-Nicol state, a film or the like placed between the two polarizers, light is irradiated from the side of the one polarizer, and light from the opposite side Refers to a point (foreign object), and it is preferable that the number of points of a density of 0.01 mm or more in diameter is 200 pieces / cm 2 or less. More preferably 100 pieces / cm2 or less, further preferably 50 pieces / cm2 or less, and still more preferably 0 to 10 pieces / cm2 or less. It is also preferable that the luminescent viscosity is 0.01 mm or less.

The filtration of the dope can be carried out by a usual method, but a method of filtration while heating at a temperature in a range that the boiling point of the solvent is not lower than the boiling point at normal pressure and the solvent does not boil under pressure is the difference in filtration pressure before and after filtration ) Is small, which is preferable.

The preferred temperature is 45 to 120 占 폚, more preferably 45 to 70 占 폚, and still more preferably 45 to 55 占 폚.

The filtration pressure is preferably small. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

2) Flexible process

Subsequently, the dope is cast (cast) on a metal support. That is, in this step, the dope is fed to the pressure die 30 through a feed pump (for example, a pressurized metering gear pump) and is fed to the endless metal belt 31, for example, a stainless belt, Or to a flexible position on a metal support such as a rotating metal drum.

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

The width of the cast is preferably 1.4 m or more from the viewpoint of productivity. More preferably 1.4 to 4 m. If it exceeds 4 m, there is a possibility that streaks may enter the manufacturing process or the stability in the subsequent conveying process may be lowered. More preferably, it is 1.6 to 2.5 m in terms of transportability and productivity.

The metal support in the casting step is preferably mirror-finished on the surface, and as the metal support, a stainless steel belt or a drum finished by plating the cast iron surface is preferably used.

The surface temperature of the metal support of the softening process is preferably from -50 DEG C to less than the boiling point of the solvent because the higher the temperature, the higher the drying speed of the web can be. However, if the surface temperature is too high, .

The preferred support temperature is 0 to 55 占 폚, more preferably 25 to 50 占 폚. Alternatively, it is preferable that the web be gelled by cooling to peel off the drum in a state containing a large amount of residual solvent.

The method of controlling the temperature of the metal support is not particularly limited, but there is a method of blowing warm air or cold air, or a method of bringing warm water into contact with the metal support. The use of hot water is preferable because heat is efficiently transferred and the time until the temperature of the metal support becomes constant is short. In the case of using warm air, a wind having a temperature higher than a desired temperature may be used.

3) Solvent evaporation process

This step is a step of heating a web (soft dope on a flexible support and a formed dope film as a web) on a flexible support to evaporate the solvent.

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

From the viewpoints of surface quality, moisture permeability and releasability, it is preferable that the web is peeled off from the support within 30 to 120 seconds at the time of forming the stainless steel belt and at 5 to 40 seconds at the time of drum formation.

4) Peeling process

The web is then peeled from the metal support. That is, this step is a step of peeling the web from which the solvent has evaporated on the metal support at the peeling position. The stripped web is sent to the next process.

The temperature at the peeling position on the metal support is preferably in the range of -50 to 40 캜, more preferably in the range of 10 to 40 캜, and in the range of 15 to 30 캜 in the case of forming the stainless steel belt And most preferably -30 to 10 DEG C at the time of forming the drum.

The amount of the residual solvent of the web on the metal support at the time of peeling is appropriately controlled depending on the strength of the drying condition, the length of the metal support, and the like. In order for the cellulose ester film to exhibit a predetermined toughness value, it is preferable to control the amount of the residual solvent at the time of peeling the web from the metal support to 15 to 40 mass%, more preferably 20 to 35 mass% to be.

In the present invention, the amount of the residual solvent is defined by the following formula.

M is the mass of the sample taken from the web or film at any point during or after the production, and N is the mass after heating the M at 115 占 폚 for 1 hour.

The peeling tension when peeling the film from the metal support is preferably set to 300 N / m or less. More preferably, it is in the range of 196 to 245 N / m, but when it is easy to cause wrinkling at the time of peeling, peeling is preferably carried out with a tension of 190 N / m or less, preferably 100 to 190 N / m.

5) Drying, stretching, width maintenance process

(dry)

In the drying process of the cellulose ester film, the web is preferably peeled off from the metal support and dried, so that the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, particularly preferably 0% To 0.01% by mass or less.

In the film drying process, a roll drying method (a method of alternately passing the web through a plurality of rolls disposed in the upper and lower rolls) or a method of drying the web while conveying the web in a tenter system is employed. For example, after peeling, a drying device 35 for conveying webs alternately in a plurality of rollers arranged in a drying apparatus and / or a tenter stretching device 34 for clipping and conveying both ends of the web with clips are used , The web is dried.

The means for drying the web is not particularly limited and generally can be carried out by hot air, infrared rays, heating rolls, microwaves or the like, but it is preferable to conduct it by hot air in terms of simplicity. Too rapid drying tends to impair the planarity of the finished film. Drying at a high temperature is preferably carried out at a residual solvent of about 8 mass% or less. As a whole, the drying is carried out within a range of approximately 40 to 250 ° C. Particularly preferably in the range of 40 to 200 ° C. The drying temperature is preferably raised stepwise, preferably to about 100 to 150 ° C, and is preferably heated for 5 minutes to 30 minutes, more preferably 6 minutes to 12 minutes.

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

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

(Stretching and width maintenance)

Subsequently, it is preferable to stretch the web from the metal support in at least one direction. By the stretching treatment, the orientation of the molecules in the film can be controlled. In order to obtain the aimed retardation values Ro and Rt in the present invention, even when the cellulose ester film has the constitution of the present invention and contains the retardation increasing agent, the refractive index control is controlled by the control of the transporting tension and the stretching operation . For example, it is possible to vary the retardation value by lowering or increasing the tension in the longitudinal direction.

Specific examples of the stretching method include biaxial stretching or monoaxial stretching in sequence or simultaneously with respect to the longitudinal direction (film forming direction; flexible direction; MD direction) and the direction perpendicular to the film surface . Preferably, the film is a biaxially stretched film obtained by biaxially stretching in a stretching direction (MD direction) and a width direction (TD direction), but the cellulose ester film according to the present invention may be a uniaxially stretched film or an unstretched film . Further, the stretching operation may be performed in multiple steps. In the case of biaxial stretching, simultaneous biaxial stretching may be performed, or may be performed stepwise. In this case, the term "stepwise" means that, for example, the stretching in which the stretching directions are different can be sequentially performed, the stretching in the same direction can be divided into multiple steps, and the stretching in different directions can be added to any one of the steps. That is, for example, the following stretching steps are possible:

Stretching in the flexible direction? Stretching in the width direction? Stretching in the flexible direction? Stretching in the flexible direction

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

The simultaneous biaxial stretching may include stretching in one direction and shrinking the other by relaxing the tension.

The stretching magnifications in the biaxial directions orthogonal to each other are preferably set in the range of 0.01 to 2.0% in the softening direction (MD direction) and 10 to 50% in the width direction, respectively, and 0.1 to 1.0% And preferably in the range of 20 to 40% in the width direction. The amount of the residual solvent at this time is preferably in the range of 15 to 40% in order to make the cellulose ester film exhibit a predetermined toughness value.

The stretching temperature is usually preferably in the range of Tg to Tg + 60 占 폚 of the resin constituting the film. In general, the stretching temperature is preferably 120 占 폚 to 200 占 폚, more preferably 130 占 폚 to 200 占 폚, and still more preferably 140 占 폚 and 190 占 폚 or lower.

There is no particular limitation on the amount of the residual solvent in the film at the time of stretching, but in order for the cellulose ester film to exhibit a predetermined toughness value, the amount of the residual solvent in the stretching treatment in the width direction is preferably from 2 to 5 mass% .

There is no particular limitation on the method of extending the web. For example, there are a method in which a peripheral speed difference is generated in a plurality of rolls and a longitudinal direction is elongated using a roll peripheral speed difference therebetween, a method in which both ends of the web are fixed with clips or pins, A method of stretching in the machine direction in the longitudinal direction, a method of stretching in the transverse direction in the transverse direction, a method of stretching in the transverse direction in the longitudinal direction, and a method of stretching in both the transverse direction and the transverse direction. Of course, these methods may be used in combination. Among them, it is particularly preferable to perform stretching in the transverse direction (transverse direction) by a tenter method of gripping both ends of the web with clips or the like.

In the so-called tenter method, it is preferable to drive the clip portion by the linear drive method, since smooth drawing can be performed and the risk of breakage can be reduced.

The stretching in the width direction or the transverse direction in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

When the slow axis or the fast axis of the cellulose ester film according to the present invention is present in the film surface and the angle forming the film forming direction in the entire film width and the entire length is? 1,? 1 is preferably -1 degrees or more and +1 degrees or less , More preferably not less than -0.5 占 and not more than 0.5 占 more preferably not more than -0.2 占 and not more than 0.2 占.

This? 1 can be defined as an orientation angle, and the measurement of? 1 can be performed by using an automatic birefringence system KOBRA-21ADH (Oji Keiso Koki Kiki). and? 1 satisfy the above-described relations, it is possible to obtain a high luminance in a display image, to suppress or prevent light leakage, and to contribute to obtaining faithful color reproduction in a color liquid crystal display device.

6) Winding process

Finally, by winding the obtained web (finished film), a cellulose ester film is obtained. More specifically, the amount of the residual solvent in the web becomes 2% by mass or less, and then the film is taken up as a film by the winder 37. When the residual solvent amount is 0.4% by mass or less, a film having good dimensional stability can be obtained . Particularly preferably 0.00 to 0.10% by mass.

As the winding method, those generally used may be used, and there are a static torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like.

Prior to winding, the end portion may be slit and cut with a width to become a product, and knurling (embossing) may be performed at both ends in order to prevent adhesion or scratching in the winding body. A method of knurling can be performed by heating or pressing a metal ring having a concavo-convex pattern on its side surface. Further, the holding portion of the clip at both ends of the film is usually cut off because the film is deformed and can not be used as a product. If deterioration of the material by heat does not occur, it is reused after recovery.

The cellulose ester film is preferably a long film, specifically, about 100 m to 10000 m, and is usually provided in a roll form. The width of the film is preferably from 1.4 to 4 m, more preferably from 1.4 to 4 m, and further preferably from 1.6 to 3 m in order to meet the demand for enlargement of the liquid crystal display device and production efficiency.

It is preferable that the cellulose ester film laminate produced by the above method is subjected to an aging treatment for 3 days or more under the condition of 50 占 폚 or more after packaging on the outer peripheral portion. By carrying out such treatment, it becomes possible to control the toughness of the cellulose ester film to a value within the preferable range described above, and it is preferable to control the value within this range from the viewpoint of improvement of dimensional stability.

[Polarizer]

The polarizer, which is a main component of the polarizing plate of the present invention, is a device that allows only light of a polarization plane in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film includes a polyvinyl alcohol film stained with iodine and a dichroic dye stained.

As the polarizer, a polarizer in which a polyvinyl alcohol aqueous solution is formed, uniaxially stretched, dyed, uniaxially stretched, and preferably subjected to a durability treatment with a boron compound can be used. The thickness of the polarizer is preferably from 2 to 30 占 퐉, more preferably from 2 to 15 占 퐉, further preferably from 3 to 10 占 퐉, from the viewpoint of the thin film suitability, from the viewpoint of further thin film suitability and handling properties.

Further, an ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a degree of polymerization of 2000 to 4000 and a saponification degree of 99.0 to 99.99 mol% described in JP-A-2003-248123 and JP-A-2003-342322 Alcohol is also preferably used. Among them, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 占 폚 is preferably used. The polarizer using the ethylene-denatured polyvinyl alcohol film has excellent polarizing performance and endurance performance, and has less color unevenness and is particularly preferably used in a large-sized liquid crystal display device.

In addition, coating type polarizers were produced by the methods described in Japanese Patent Application Laid-Open Nos. H11-100161, H46-1205, JP4751481, and JP4804589 to prepare a cellulose ester film To form a polarizing plate.

[UV curable adhesive]

In the polarizing plate of the present invention, as shown in Fig. 1, it is preferable that each of the above-described protective film A and protective film B and the polarizer are bonded by an ultraviolet curable adhesive.

In the present invention, by applying an ultraviolet curable adhesive to the protective film A and the polarizer or to the protective film B and the polarizer, high productivity and excellent durability of the polarizer can be obtained.

[Composition of ultraviolet curable adhesive]

As the ultraviolet curable adhesive composition for a polarizing plate, there are known a photo-radical polymerizable composition using photo-radical polymerization, a photo-cationic polymerizable composition using photo-cation polymerization, and a hybrid-type composition using both photo radical polymerization and photo cationic polymerization.

Examples of the photo-radical polymerization type composition include compositions containing a radical polymerizing compound containing a polar group such as a hydroxyl group or a carboxyl group and a radical polymerizing compound not containing a polar group in a specific ratio as described in JP-A-2008-009329 It is known. In particular, the radical polymerizing compound is preferably a compound having a radically polymerizable ethylenic unsaturated bond. Preferable examples of the compound having a radically polymerizable ethylenically unsaturated bond include a compound having a (meth) acryloyl group. Examples of the compound having a (meth) acryloyl group include N-substituted (meth) acrylamide-based compounds, (meth) acrylate-based compounds and the like. (Meth) acrylamide means acrylamide or methacrylamide.

As the photo cationic polymerization type composition, there may be mentioned (a) a cationic polymerizable compound, (?) A photo cationic polymerization initiator, (?) A A photosensitizer exhibiting maximum absorption in light, and an ultraviolet curable adhesive composition containing (delta) naphthalene-based photo-sensitization assistant. However, an ultraviolet curable adhesive other than these may be used.

(Pre-processing step)

The pretreatment step is a step of performing an adhesion facilitating treatment on the adhesion surface of the cellulose ester film to the polarizer. When the protective film A and the protective film B are bonded to the both surfaces of the polarizer, the adhesion facilitating treatment is performed on the adhesion surface of each protective film to the polarizer. Examples of the adhesion facilitating treatment include corona treatment and plasma treatment.

(Application step of ultraviolet curing type adhesive)

In the application step of the ultraviolet curable adhesive, the ultraviolet curable adhesive is applied to at least one of the bonding surfaces of the polarizer and the protective film. When the ultraviolet curable adhesive is directly applied to the surface of the polarizer or the protective film, there is no particular limitation on the application method thereof. For example, various wet coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. It is also possible to use a method in which an ultraviolet curable adhesive is poured between the polarizer and the protective film, and then the film is uniformly spread by pressing with a roll or the like.

(Bonding step)

After the ultraviolet curing type adhesive is applied by the above method, it is treated in the bonding step. In this bonding step, for example, when an ultraviolet curable adhesive is applied to the surface of the polarizer in the preceding coating step, the protective film is superposed thereon. In the case where the ultraviolet curable adhesive is first applied to the surface of the protective film in the preceding coating step, the polarizer is superimposed thereon. Further, when an ultraviolet curable adhesive is poured between the polarizer and the protective film, the polarizer and the protective film A are superimposed in this state. When the protective film A and the protective film B are respectively adhered to both surfaces of the polarizer and when an ultraviolet curable adhesive is used on both surfaces, the protective film A and the protective film B are superimposed on both surfaces of the polarizer through an ultraviolet- do. Normally, when the protective film A is superimposed on one side of the polarizer and the protective film A and the protective film B are laminated on both sides of the polarizer side and the protective film A side and also on the polarizer side in this state, The protective film A on the both sides and the protective film B side) by means of a pressure roller or the like. As the material of the pressure roller, metal or rubber can be used. The pressure rollers disposed on both sides may be the same material or different materials.

(Curing Process)

In the curing step, ultraviolet rays are irradiated to an uncured ultraviolet curable adhesive, and a cationic polymerizable compound (for example, an epoxy compound or an oxetane compound) or a radical polymerizable compound (for example, an acrylate compound or an acrylamide compound Compound or the like) is cured, and the superposed polarizer and the protective film A or the polarizer and the protective film B are bonded to each other via the ultraviolet curable adhesive. When the protective film A is bonded to one surface of the polarizer, the active energy ray may be irradiated from either the polarizer side or the protective film A side. When the protective film A and the protective film B are bonded to both surfaces of the polarizer, the protective film A and the protective film B are superimposed on both sides of the polarizer with an ultraviolet curable adhesive interposed therebetween. It is advantageous to simultaneously cure the curable adhesive.

The irradiation condition of the ultraviolet ray may be any suitable condition as long as it is a condition capable of curing the ultraviolet curable adhesive applied in the present invention. The dose of ultraviolet rays is preferably 50 to 1,500 mJ / cm2, more preferably 100 to 500 mJ / cm2, in terms of accumulated light quantity.

The line speed is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, and further preferably 10 to 100 m / min, although it depends on the curing time of the adhesive. min. When the line speed is 1 m / min or more, productivity can be secured, or the damage to the protective film A can be suppressed, and a polarizer excellent in durability can be manufactured. When the line speed is 500 m / min or less, the ultraviolet curing type adhesive agent having sufficient hardness and having the desired hardness can be formed with sufficient curing of the ultraviolet ray curing type adhesive agent.

"Display"

The polarizing plate according to the present invention can be used for various display devices, but is particularly preferably applied to a liquid crystal display device.

As a liquid crystal display device having a polarizing plate of the present invention, a twisted nematic (TN) mode, a super twisted nematic (STN) mode, an in-plane switching (IPS) mode, an optically compensated birefringence (OCB) (MVA), a hybrid Aligned Nematic (HAN), and the like. In order to increase the contrast, VA (MVA, PVA) method is preferable.

[Example]

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the examples, "%" is used, and "mass%" is used unless otherwise specified.

&Quot; Preparation of polyethylene terephthalate film as protective film A "

(Production Example 1: Production of PET (A)

After the temperature of the esterification reaction vessel was elevated to 200 占 폚, 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were fed and 0.017 part by mass of antimony trioxide, 0.064 parts by mass of magnesium acetate tetrahydrate, And 0.16 parts by mass of ethylamine. Subsequently, the mixture was subjected to pressure-esterification at a gauge pressure of 0.34 MPa and at a temperature of 240 占 폚, and then the esterification reaction vessel was returned to normal pressure and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260 DEG C over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added. After 15 minutes, dispersion treatment was carried out with a high-pressure disperser. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction can, and a polycondensation reaction was carried out under reduced pressure at 280 占 폚.

After completion of the polycondensation reaction, filtration treatment was carried out with a Nasron (registered trademark) filter having a 95% cut diameter of 5 탆, extruded from the nozzle in the form of a strand and subjected to filtration treatment (pore diameter: 1 탆 or less) Cooled, solidified, and cut into a pellet shape (the resultant was also referred to as " PET (A) ").

(Production Example 2: Production of PET (B)

10 parts by mass of a dried ultraviolet absorber (2,2 '- (1,4-phenylene) bis (4H-3,1-benzoxazinone-4-one) and 90 parts by mass of PET , And a polyethylene terephthalate resin (B) containing an ultraviolet absorber was obtained by using a kneading extruder (the resultant was also referred to as " PET (B) ").

(Production Example 3: Production of Adhesive Modifying Coating Solution)

Ester exchange reaction and polycondensation reaction were carried out according to a conventional method to obtain a mixture of 46 mol% of terephthalic acid, 46 mol% of isophthalic acid and 5 mol% of sodium 5-sulfonate isophthalate (relative to the entire dicarboxylic acid component) as a dicarboxylic acid component Mol%, and a water-dispersible sulfonic acid metal base-containing copolymerized polyester resin having a composition of 50 mol% of ethylene glycol and 50 mol% of neopentyl glycol as glycol components (with respect to the entire glycol component). Subsequently, 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve and 0.06 parts by mass of a nonionic surfactant were mixed with heating, and when the temperature reached 77 占 폚, And 5 parts by mass of a metal base-containing copolymerizable polyester resin were added, and the mixture was continuously stirred until the lump of the resin disappeared. Thereafter, the resin aqueous dispersion was cooled to room temperature to obtain a homogeneous water dispersible copolymer polyester resin liquid having a solid content concentration of 5.0 mass%. After dispersing 3 parts by mass of agglomerated silica particles (Siacia 310, manufactured by Fuji Silysia Co., Ltd.) in 50 parts by mass of water, 99.46 parts by mass of the water-dispersible copolymerized polyester resin solution was added with 0.54 And 20 parts by mass of water was added with stirring to obtain an adhesive modified coating liquid.

[Production of PET film 1]

A polyethylene terephthalate film having a three-layer structure was produced by the following method.

90 parts by mass of the PET (A) resin pellets containing no particles and 10 parts by mass of the PET (B) resin pellets containing the ultraviolet absorber were dried under reduced pressure (1 Torr) at 135 DEG C for 6 hours and then supplied to an extruder Further, the PET (A) was dried by an ordinary method and fed to an extruder (for both outer layers), and dissolved at 285 캜. The two kinds of polymers were filtered twice with a filter material of a stainless steel sintered body (nominal filtration accuracy of 10 μm and a particle size of 95%) and laminated with a two-kind three-layer confluence block, The film was wound around a casting drum having a surface temperature of 30 DEG C by an electrostatic casting method to be cooled and solidified to obtain an unstretched film. At this time, the discharge amount of each extruder was adjusted so that the thickness ratio of each layer was 10 (outer layer): 80 (middle layer): 10 (outer layer).

Subsequently, the adhesive modifying coating liquid was applied on both sides of the unstretched PET film so as to have a coating amount after drying of 0.08 g / m < 2 > by a reverse roll method, followed by drying at 80 DEG C for 20 seconds.

The unstretched film on which the coated layer was formed was preliminarily heated to 145 占 폚 using a heated roll group and an infrared heater and then stretched three times in the running direction (MD direction) with a group of rolls having peripheral speed. Thereafter, the film was led to a tenter stretching machine and led to a hot air zone at a temperature of 135 캜 while grasping the end of the film with a clip, and stretched four times in the width direction (TD direction). Thus, a biaxially oriented PET film 1 (film thickness 60 m) was obtained.

[Production of PET films 2 to 17]

In the production of the PET film 1, the number of times of filtration of the molten polymer before film formation by the electrostatic casting method, the presence or absence of preheating before stretching in the MD direction, the stretching magnification in the MD direction and the TD direction, PET films 2 to 17 were prepared in the same manner as in the PET film 2 except that the PET films 2 to 17 were changed as shown in Table 1 below.

[Evaluation of elastic modulus of PET film]

Each of the PET films prepared above was subjected to humidity control for 24 hours under an environment of 23 캜 and 55% RH, and the elastic modulus was measured according to the method described in JIS K7127. As a tensile tester, Tencilon RTC-1225 manufactured by Orientech Co., Ltd. was used, and the shape of the test piece was 120 mm (length) × 10 mm (width), and 100 mm And the test speed was 100 mm / min. Further, the measurement was performed five times for each of the MD direction and the TD direction per one sample, and an average value in each direction was calculated. The results are shown in Table 1 below.

&Quot; Preparation of cellulose acetate film as protective film B &

[Production of cellulose acetate film 1]

(Preparation of fine particle dispersion diluent)

10 parts by mass of Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter: 16 nm, apparent specific gravity: 90 g / L) and 90 parts by mass of ethanol were mixed and stirred for 30 minutes with a dissolver, To prepare a fine particle dispersion.

To the obtained fine particle dispersion, 88 parts by mass of dichloromethane was added with stirring, and the mixture was stirred and mixed with a dissolver for 30 minutes, followed by dilution. The obtained solution was filtered with a polypropylene wind cartridge filter TCW-PPS-1N manufactured by Advantec Co., Ltd. to obtain a fine particle dispersion diluted solution.

(Preparation of in-line addition liquid)

15 parts by mass of Tinuvin 928 (manufactured by BASF Japan) and 100 parts by mass of dichloromethane as an ultraviolet absorber were placed in a sealed container, which was completely dissolved by heating and filtration. To the obtained solution, 36 parts by mass of the above-mentioned fine particle dispersion diluted solution was added with stirring, and further stirred for 30 minutes. Then, 6 parts by mass of cellulose ester 1 (acetyl group substitution degree 2.80, Mn = 75000, Mw = 150000, Mw / Mn = 2.0) Was added with stirring, and the mixture was further stirred for 60 minutes. The solution thus obtained was filtered with Pine Met NF manufactured by Nippon Seisen Co., Ltd. to obtain an inline addition liquid. A filter medium having a nominal filtration accuracy of 20 占 퐉 was used.

(Preparation of Dope)

The following components were put in a hermetically sealed container and completely dissolved with heating and stirring. The obtained solution was filtered through an Azumino No.24 manufactured by Azumi Co., Ltd. to obtain a main dope.

<The composition of main dop>

86 parts by mass of cellulose acetate (acetyl group degree of substitution: 2.35, Mn = 80000, Mw = 135000, Mw / Mn = 1.68)

2 parts by mass of an ester compound (the above compound FB-16)

7 parts by weight of a sugar ester (compound FA-20)

2 parts by mass of a retardation-increasing agent (Compound 1-2)

Dichloromethane 430 parts by mass

Ethanol 11 parts by mass

100 parts by mass of the main dope and 2.5 parts by mass of the inline addition liquid were thoroughly mixed with an inline mixer (Mixer Hi-Mixer in a Toray stationary tube, SWJ) to obtain a dope.

(Film forming step)

The obtained dope was uniformly smoothed on a stainless steel band support by means of a belt smoothing device under the conditions of a solution temperature of 35 DEG C and a width of 1.95 m. On the stainless steel band support, the obtained organic solvent in the dope film was evaporated until the residual solvent amount became 30% by mass to form a web, and then the web was peeled from the stainless band support. The resulting web was further dried at 35 DEG C and then slit to a width of 1.90 m. Thereafter, the web was stretched by 0.5% in a running direction (MD direction) to a roll group having a peripheral speed difference at 160 캜. Subsequently, the film was stretched by 30% in the TD direction (film width direction) with a tenter. The amount of residual solvent in the web at the start of the stretching in the TD direction was 3 mass%.

Thereafter, the obtained film was dried at 120 DEG C for 15 minutes while being conveyed in a plurality of rolls in a drying apparatus, and then slit to 1.6m width to obtain a cellulose acetate film. And the end portion was subjected to knurling processing. The elongated cellulose acetate film thus obtained having a width of 1.6 m, a length of 6000 m and a thickness of 30 탆 was wound in the longitudinal direction to obtain a laminated roll 1 of the cellulose acetate film 1.

(Aging treatment of laminated roll body)

Thereafter, the outer periphery of the laminated roll 1 was packed in two layers using a moisture-impermeable film packaging material in which aluminum was vapor-deposited on a polyethylene resin film having a thickness of 50 占 퐉 and the end of the winding core was fixed with a rubber band, Respectively.

Subsequently, the produced laminated roll 1 A was aged for 3 days under a constant-temperature environment of 50 캜 to prepare a cellulose acetate film 1.

[Production of cellulose acetate films 2 to 28]

In the production of the cellulose acetate film 1, the amount of the residual solvent at the time of peeling the web from the stainless steel band support, the stretching magnification in the MD direction at the peeling of the web, the amount of the residual solvent at the start of the stretching in the TD direction, Except that the production conditions were as shown in Table 2 below for the presence or absence of the cellulose acylate film, the acetyl group substitution degree of the raw material cellulose acetate, the film thickness of the film and the kind of the retardation increasing agent, Respectively. Of the retardation enhancers described in Table 2, the compounds (1-1) and (1-4) have the structures described above, and the triazine compounds and the rod-shaped compounds have the following structures.

[Evaluation of retardation of cellulose ester film]

The retardation value Ro in the in-plane direction and the retardation value Rt in the thickness direction were measured for each of the cellulose ester films prepared above. The results are shown in Table 2 below.

[Evaluation of toughness of cellulose ester film]

Each of the cellulose ester films prepared above was measured by the following measuring method to calculate the toughness in each of the MD direction and the TD direction.

1) Five optical films are cut out in the direction of 120 mm (MD direction) × 10 mm (TD direction), and used as MD test specimens. The obtained test piece is conditioned for 24 hours under an environment of 23 ° C and 55% RH.

2) Then, the tensile modulus of the test piece was measured by the method described in JIS K7127. Tensilon RTC-1225 manufactured by Orientech Co., Ltd. was used to hold the upper and lower ends of the test piece in the longitudinal direction (MD direction) at a distance of 100 mm between the chucks (the fitting allowance was measured at the upper and lower ends of the test piece respectively 10 mm), the test piece was stretched in the longitudinal direction (MD direction) at a rate of 100 mm / min to measure the stress (breaking point stress T) and elongation (breaking elongation E) The total is measured five times (for a total of five). The measurement is performed in an environment of 23 ° C and 55% RH.

3) The maximum value of the five measured values of the obtained breaking point stress T (N / mm 2 or MPa), the maximum value of the five measured values of the breaking point elongation E (%) and the film thickness t And toughness in the MD direction is calculated.

Toughness = breaking point stress T (N / mm 2 or MPa) × cross sectional area A (mm 2) of the test piece in the direction orthogonal to the tensile direction x (breaking elongation E (%) / 100) ^1/2

Sectional area of the test piece A (mm 2) = width of the test piece 10 (mm) x thickness of the test piece t (mm)

Likewise, for the toughness in the TD direction of the optical film, five optical films are cut out in a size of 120 mm (TD direction) × 10 mm (MD direction), and a test piece for TD direction measurement is prepared. The toughness in the TD direction is calculated by carrying out the same measurement as above except that the test piece is used to stretch the test piece in the longitudinal direction (TD direction).

The results obtained by measurement are shown in Table 2 below.

&Quot; Production of Polarizer &quot;

[Production of Polarizer]

A polyvinyl alcohol film having an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% and a thickness of 50 mu m was immersed in hot water at 30 DEG C for 60 seconds and swelled. Subsequently, the obtained film was dipped in an aqueous solution having a concentration of 0.3% of iodine / potassium iodide (mass ratio = 0.5 / 8), and was stretched to 3.0 times and dyed. Thereafter, the obtained film was stretched in an aqueous solution of boric ester at 65 캜 so that the total draw ratio became 5.5. Thereafter, the obtained film was dried in an oven at 40 占 폚 for 3 minutes to obtain a polarizer having a thickness of 10 占 퐉.

Further, in the production of the polarizer, a polarizer having a thickness of 1.5 탆, 2 탆, 15 탆 or 18 탆 was further prepared by changing the thickness of the unstretched polarizer to 8 탆, 10 탆, 75 탆 and 90 탆, respectively .

[Preparation of ultraviolet curable adhesive liquid]

The following components were mixed and defoamed to prepare an ultraviolet curable adhesive liquid. Further, triarylsulfonium hexafluorophosphate was blended as a 50% propylene carbonate solution, and the solid content of triarylsulfonium hexafluorophosphate was shown below.

45 parts by mass of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate

40 parts by mass of Polyd GT-301 (alicyclic epoxy resin manufactured by Daicel Chemical Industries, Ltd.)

15 parts by mass of 1,4-butanediol diglycidyl ether

Triarylsulfonium hexafluorophosphate 2.3 parts by mass

9,10-dibutoxyanthracene 0.1 part by weight

2.0 parts by mass of 1,4-diethoxynaphthalene

[Production of polarizer]

(Production of polarizing plate 1)

According to the following method, the polarizing plate 1 (101) including the constitution shown in Fig. 1 was produced. The numerical values in parentheses indicate the numbers of the respective constituent elements shown in Fig.

First, the cellulose ester film 1 prepared above was used as the cellulose ester film 105 as the protective film B, and its surface was subjected to a corona discharge treatment. The conditions of the corona discharge treatment were a corona output power of 2.0 kW and a line speed of 18 m / min. Next, the ultraviolet curing type adhesive solution prepared above was applied to the corona discharge treated surface of the cellulose ester film 1 (105) with a bar coater so that the film thickness after curing became about 3 μm, and the photocurable resin layer 103B . The polyvinyl alcohol-iodine-based polarizer (104, thickness 10 mu m) prepared above was bonded to the obtained photo-curable resin layer 103B.

Subsequently, the surface of the PET film 1 prepared above was used as the protective film A (102), and its surface was corona discharge treated. The conditions of the corona discharge treatment were a corona output power of 2.0 kW and a velocity of 18 m / min.

Then, the ultraviolet curing type adhesive solution prepared above was applied to the corona discharge treated surface of the PET film 1 (102) with a bar coater so as to have a film thickness after curing of about 3 mu m to form an ultraviolet curable adhesive layer 103A Respectively.

A polarizer 104 bonded to one side of the cellulose ester film 105 is bonded to the ultraviolet curable adhesive layer 103A to form a protective film A (PET film) 102 / ultraviolet curable adhesive layer 103A / polarizer 104 / ultraviolet curable adhesive layer 103B / protective film B (cellulose ester film, 105) were laminated. At that time, the cellulose ester film 105 was bonded so that the slow axis of the cellulose ester film 105 and the absorption axis of the polarizer 104 were orthogonal to each other.

Ultraviolet rays were irradiated from both sides of the laminate so that the accumulated amount of light was 750 mJ / cm 2 using an ultraviolet irradiator equipped with a belt conveyor (lamp was a D valve manufactured by Fusion UV Systems Co., Ltd.) The ultraviolet curable adhesive layers 103A and 103B were cured to prepare the polarizing plate 1 (101).

[Production of polarizing plates 2 to 48]

Polarizing plates 2 to 48 were produced in the same manner as in the production of the polarizing plate 1 except that the kind of the protective film A, the kind of the protective film B, and the film thickness of the polarizer were changed by the combination described in Table 3 below.

[Production of liquid crystal display device]

The polarizing plate on the visual side of the VA type liquid crystal display device was peeled off and the polarizing plate prepared above was joined to the liquid crystal cell via a pressure sensitive adhesive having butyl acrylate as a main component to prepare a VA type liquid crystal display device.

[Evaluation of reworkability of polarizer]

The retardation properties of the polarizing plates 1 to 48 thus prepared were evaluated according to the following methods.

The polarizing plate prepared above was cut into squares each having a size of 20 cm x 20 cm and bonded to the glass substrate using an acrylic adhesive. Subsequently, the bonded polarizing plate was peeled off from the glass at an intensity of 5N from each portion. This operation was carried out on ten polarizing plates for one type of sample, and the number of polarizing plates which had cracks on the polarizing plate and was not completely peeled off was counted. Then, ranks were assigned according to the following criteria, and the reworkability of the polarizing plate was evaluated. The results are shown in Table 3 below:

&Amp; cir &amp;: The number of polarizers not completely peeled is 0

&Amp; cir &amp;: The number of polarizers not completely peeled is 1 to 2

?: The number of polarizers that were not completely peeled was 3 to 4

X: The number of polarizers not completely peeled is 5 or more

The reworkability of the polarizing plate is practically usable if it is at or above the level of?, But it is preferably at or above the level of?, And particularly preferably at the level of?.

[Evaluation of thin film suitability of polarizer]

The total film thickness of each polarizing plate produced was measured, and the film suitability was evaluated according to the following criteria. If the rank is △ or more, it is determined that the display has a suitability as a polarizing plate for thinning request:

⊚: The total thickness of the polarizing plate is less than 100 탆

?: The total thickness of the polarizing plate is 100 占 퐉 or more and 150 占 퐉 or less

?: The total thickness of the polarizing plate is greater than 150 占 퐉 and less than 180 占 퐉

X: Layer thickness of the polarizing plate is 180 占 퐉 or more

The evaluation results obtained from the above are shown in Table 3 below.

As is clear from the results shown in Table 3, the polarizing plate of the present invention including the constitution specified in the present invention, even in the case of using the cellulose ester film thinned as the protective film B (that is, , It is found that the reworkability is excellent. Further, as a result of comparing the tensile rupture strength of the polarizing plate produced above, the polarizing plate 28 (cellulose ester film No. 12 using cellulose acetate having an acetyl group substitution degree of 2.45) was weak in strength and tore easily. The display device equipped with the polarizing plates 31, 37, and 44 has a larger color change when observed with a diagonal line than the other polarizing plates, and the polarizing plate 36 has a larger Color change slightly dropped.

This application is based on Japanese Patent Application No. 2013-138329 filed on July 1, 2013, the disclosure of which is incorporated by reference in its entirety.

1: melting pot
3, 6, 12, 15: filter
4, 13: stock kiln
5, 14: Pump pump
8, 16: conduit
10: Ultraviolet absorber input kiln
20: junction pipe
21: Mixer
30: pressure die
31: metal belt
32: Web
33: Peeling position
34: Tenter stretching device
35: Drying apparatus
41: Feeding kiln
42: stock kiln
43: pump
44: Filter

Claims (12)

A protective film A, a polarizer and a protective film B in this order,
Wherein the protective film A is a polyester film comprising a polyester,
The polyester film has a modulus of elasticity of 5.0 to 8.0 mm in at least one of the MD direction and the TD direction,
The protective film B is a cellulose ester film containing a cellulose ester,
In the cellulose ester film,
(1) the film thickness is in the range of 15 to 60 탆,
(2) A polarizing plate characterized in that the toughness is 10 to 20 in both the MD direction and the TD direction. The method according to claim 1,
Wherein the polyester is polyethylene terephthalate. 3. The method according to claim 1 or 2,
Wherein a thickness of the protective film (A) is within a range of 40 to 100 占 퐉. 3. The method according to claim 1 or 2,
The retardation value Ro in the in-plane direction defined by the following formulas (i) and (ii) is in the range of 30 to 70 nm and the retardation value Rt in the thickness direction is in the range of 100 to 140 nm Within the range, polarizer:
Formula (i): Ro = (n x -n y) × d (㎚)
Formula (ii): Rt = {( n x + n y) / 2-n z} × d (㎚)
Wherein n _x represents a refractive index in a direction x at which the refractive index becomes maximum in an in-plane direction of the film and n _y represents a refractive index in an in-plane direction of the film in a direction orthogonal to the direction x represents the refractive index in, n _z it is, represents the refractive index of the thickness direction z of the film, and d is each represents the thickness (㎚) of the film, measurement environment 23 ℃ · 55% to the measurement of the RH 590㎚ Wave length] 3. The method according to claim 1 or 2,
Wherein the cellulose ester comprises cellulose acetate in an amount of 50% by mass or more based on the total amount of the cellulose ester. 6. The method of claim 5,
And the acetyl group degree of substitution of the cellulose acetate is 2.1 to 2.95. 3. The method according to claim 1 or 2,
And the protective film B comprises a retardation increasing agent. 8. The method of claim 7,
Wherein the retardation increasing agent is represented by the following formula (1):

(Wherein R ¹ to R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a halogen atom;
Each X independently represents -O- or -OC (= O) - (wherein O is bonded to the phenyl skeleton of formula (1));
R ⁵ and R ⁶ are, each independently,
An alkyl group which may be substituted with a hydroxyl group, an ester group or an optionally substituted aromatic group when X is -O-; Or a glycidyl group,
An alkyl group which may be substituted with a hydroxyl group, an ester group or an optionally substituted aromatic group when X is -OC (= O) -; Or an aromatic group which may be substituted)
&Lt; / RTI &gt; 3. The method according to claim 1 or 2,
Wherein the protective film (A) and the protective film (B) are both bonded to the polarizer by an ultraviolet curable adhesive. 3. The method according to claim 1 or 2,
Wherein the film thickness of the polarizer is within a range of 2 to 15 占 퐉. 3. The method according to claim 1 or 2,
Wherein the thickness is within a range of 80 to 150 占 퐉. A liquid crystal display device comprising the polarizing plate according to claim 1 or 2.

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