TWI538944B - A cellulose ester film, a method for producing the same, and a polarizing plate - Google Patents

Description

Cellulose ester film, manufacturing method thereof and polarizing plate

The present invention relates to a cellulose ester film, a method for producing the same, and a method for producing the same The polarizing plate, in more detail, is excellent in adhesion between the polyvinyl alcohol (also referred to as PVA) water paste and the ultraviolet curable adhesive, and is a film and a phase. A cellulose ester film excellent in poor display properties, a method for producing the same, and a polarizing plate.

In recent years, liquid crystal display devices have become larger and thinner. The high definition is required, and the polarizing plate is required to be wider, thinner, and improved in display quality.

In the past, the protective film of the polarizing plate was thin with cellulose ester. A film, but a cellulose triacetate film (also referred to as a TAC film) which has been conventionally used is used as a retardation film in order to achieve a display quality such as a widening, a thin film, and a contrast caused by a phase difference. There will be problems.

The original TAC film has a phase difference (also called In the case of the retardation of the VA mode liquid crystal display device, the optical compensation film having a phase difference suitable for the VA mode liquid crystal display device is produced by performing a stretching process or the like by a phase difference adjusting agent containing a retardation increasing agent or the like. In order to widen or thin the film, when the high-rate stretching treatment is performed, the additive such as the phase difference adjusting agent oozes, and the haze is increased, or the whitening of the film itself is caused by the stretching, and the internal scattering is increased, and the contrast is lowered. The display quality is not good.

In addition, the use of ethylene-based substituted ethylene-based fibers A cellulose ester film of a cellulose ester having a low thiol group substitution degree such as vaso (also referred to as DAC) has a high phase difference exhibitability by stretching treatment, but the phase difference is insufficient when further thinning. Therefore, even when the DAC or the like is used, it is considered that when the film is further thinned, a retardation increasing agent is added, and both thin film formation and phase difference exhibitability are obtained.

Further, the cellulose ester film is laminated by saponification treatment In the PVA film-based polarizer, a polarizing plate can be produced. However, as an adhesive for bonding the cellulose ester film and the polarizer, in addition to the conventional saponification treatment and the PVA-based water paste, ultraviolet rays are also used. A method of hardening an adhesive, recently, it is desirable to use a two-part adhesive to bond.

However, the thin film containing the above DAC and the retardation enhancer In the cellulose ester film, when a water paste or an ultraviolet curable adhesive is used as an adhesive, a decrease in yield due to adhesion failure or a peeling of the film occurs, and it is known that there is a problem in the adhesion which is satisfied by the two adhesives. .

According to the review by the inventor, it is known that by high magnification When the film is formed into a film, the film thickness is likely to be uneven, and the standard deviation (also referred to as a deviation) of the contact angle of the film surface with respect to pure water is increased, and the ductility of the adhesive is lowered, so that the adhesion defect occurs. Also, UV hard When the chemical-based adhesive is used as an adhesive, it is known that the ultraviolet light is irradiated on the side of the retardation film containing no ultraviolet absorber, and the structure of the retardation-increasing agent is used. In particular, when a compound having light absorption in the vicinity of 320 nm is used, ultraviolet rays are used. At the time of the hardening reaction by irradiation, the ultraviolet rays are absorbed by the compound, and the adhesive layer is not sufficiently reached, and the subsequent failure is caused by the hardening.

Further, in the production of the DAC film, the compatibility with the DAC is likely to cause little foreign matter or precipitates in the production of the DAC film, and they are moved to the surface of the film by the stretching treatment, and the deviation of the contact angle of the surface of the film is more and more Big, hindering the continuity.

A method for improving the deviation of the contact angle of the surface of the film is disclosed in Patent Document 1, but the disclosed technique includes a cellulose acetate propionate and a composition containing no retardation increasing agent, which is produced by a melt casting method. The filmer does not suggest that the composition and problem of the invention of the present invention are solved.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-058410

[Summary of the Invention]

The present invention has been made in view of the above problems and circumstances, and the problem is to provide a PVA-based water paste and a polarizer. Both of the ultraviolet curable adhesives have excellent adhesion, and are a cellulose ester film excellent in film and phase difference exhibitability, a method for producing the same, and a polarizing plate.

In order to solve the above-mentioned problems, the inventors of the present invention have found that in the course of reviewing the cause of the above problems, it is found that a polyethylene terephthalate having a lower degree of substitution with an acetyl group and a retardation increasing agent have a specific range of pure The present invention can be solved by solving the problem of a cellulose ester film having a predetermined range of deviation between the contact angle of water and the contact angle and a light transmittance of light of a specific wavelength.

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

A cellulose ester film which is a cellulose ester film containing at least a cellulose acetate (resin A) having a degree of substitution of an ethylenic group of from 2.1 to 2.6 and a retardation increasing agent, characterized in that the cellulose The contact angle of the pure water on the surface of the ester film is in the range of 30 to 75°, and the standard deviation of the contact angle at 20 o'clock in the width direction of the film is in the range of 0.05 to 3.0°, and is 320 nm. The light transmittance of the wavelength is 80% or more.

2. The cellulose ester film according to the above item 1, wherein the contact angle is within a range of 0.05 to 1.5° when the contact angle is measured at 20 points at equal intervals in the film width direction.

3. The cellulose ester film according to the above item 1, wherein the mixing ratio of the resin B represented by the following formula 1 is in the range of 10 to 90%. a cellulose acetate propionate (resin B) having a degree of substitution of the resin A and the ethyl thiol group in the range of 1.4 to 2.0 and a degree of substitution of the fluorenyl group of 0.5 to 1.5, and a resin B of the formula 1 Mixing ratio = (mass of resin B) / (mass of resin A + mass of resin B) × 100 (%).

4. The cellulose ester film according to the above item 3, wherein the mixing ratio of the resin B is in the range of 20 to 70%.

5. The cellulose ester film according to item 3 above, wherein the aforementioned tree The absolute value of the difference in the total thiol substitution degree of the fat A and the resin B satisfies the following formula 2, the total thiol substitution degree of the resin B, the total thiol substitution degree of the resin A, ≦0.3.

6. The cellulose ester film according to the above item 1, wherein the cellulose ester film has a film thickness of from 20 to 38 μm.

The cellulose ester film according to any one of the above-mentioned items (1), wherein the retardation value Re in the in-plane direction of the cellulose ester film represented by the following formula (i) is in the range of 45 to 60 nm, The retardation value Rth in the film thickness direction expressed by the formula (ii) is in the range of 110 to 140 nm, and the formula (i): Re = (n _{x -} n _y ) × d (nm)

Formula (ii): Rth={(n _x +n _y )/2-n _z }×d(nm) (in the formulas (i) and (ii), n _x represents the in-plane direction of the film, and the refractive index The refractive index of the largest direction x. n _y represents the refractive index of the direction y orthogonal to the direction x in the in-plane direction of the film. n _z represents the refractive index of the thickness direction z of the film, and d represents the thickness of the film. (nm)).

8. The cellulose ester film according to the above item 1, wherein the retardation-increasing agent is a nitrogen-containing heterocyclic compound having a structure represented by the following general formula (1), (In the formula, A represents a pyrazole ring or an imidazole ring. Each of Ar ₁ and Ar ₂ represents an aromatic hydrocarbon ring or an aromatic hetero ring, and may have a substituent. R ₁ represents a hydrogen atom, an alkyl group, a fluorenyl group, or a sulfonyl group. , alkoxycarbonyl, or aryloxycarbonyl. q represents an integer from 1 to 2, and n and m each represent an integer from 1 to 3.

The cellulose ester film according to any one of the items 1 to 8, wherein the retardation increasing agent is contained in a ratio of 0.1 to 5% by mass based on the cellulose ester.

A method for producing a cellulose ester film, which is a method for producing a cellulose ester film of a cellulose ester film according to any one of the items 1-9, characterized in that the method comprises the steps of: a cellulose ester Dissolving in a solvent, preparing a dope, and performing a filtering step, casting a die onto a support body of a rotary drive metal endless belt or a rotating drum by a die, forming a belly a step of peeling off the web from the support as a film, a step of stretching and drying the peeled film, and winding the dried film into a roll, wherein the main solvent is at a pressure of 1 atm (boiling point + 5 ° C) to (boiling point + 20 ° C) The gel is filtered using a leaf disk filter at a temperature within the range, and the residual solvent amount is in the range of 2 to 10% by mass, and the film is oriented at an extension speed defined by the following formula 3 Stretching in the range of 250~500%/min, formula 3 extension speed (%/min)=[(d1/d2)-1]×100(%)/t

(In the formula 3, the width dimension of the extending direction of the deuterated cellulose film after d1 is extended, the width dimension of the extending direction of the deuterated cellulose film before the d2 is extended, and the time required for the extension of the t system (min) )).

A polarizing plate characterized in that the cellulose ester film according to any one of the above items 1 to 9 is followed by a water paste and a polarizer.

A polarizing plate characterized in that the cellulose ester film according to any one of the above items 1 to 9 is followed by a UV-curable adhesive and a polarizer.

According to the above-described means of the present invention, it is possible to provide a cellulose ester which is excellent in adhesion to both a PVA-based water paste and an ultraviolet-curable adhesive, and which is excellent in film and phase difference exhibitability. Film, method of producing the same, and polarizing plate.

The display mechanism or the action mechanism of the effect of the present invention is unknown Indeed, but presumably as follows.

Contains easy filming and high latency by extension processing When the cellulose ester film of the DAC and the retardation-increasing agent is formed by thinning, the film thickness tends to become uneven, and the standard deviation of the contact angle of the film surface with respect to pure water (hereinafter also referred to as When the variation is large, the ductility of the PVA-based water paste or the ultraviolet-curable adhesive is deteriorated, so that the adhesion defect is likely to occur. This is presumed to be due to the small amount of foreign matter or precipitates generated by the poor compatibility between the retardation agent and the DAC, and the film is moved to the surface of the film during the stretching treatment to form minute irregularities on the surface of the film to increase the variation.

Also, when using an ultraviolet curing type adhesive, if the fiber is not When the light transmittance of the wavelength of 320 nm of the vitamin film is set to a specific value or more, it is found that the curing by the ultraviolet ray adhesive is insufficient, and the adhesion defect is caused. This important reason is a detailed review of the results of the components contained in the cellulose ester film, and it is presumed that a UV-absorbing energy, that is, a retardation-increasing agent having a low light transmittance of 320 nm is used.

The inventors reviewed the results of the problem in detail and found that the film The PVA-based water paste and the ultraviolet-curable adhesive are improved by a cellulose ester film containing a retardation increasing agent having a light transmittance of 320 nm or more and a specific value or more within a specific range of the surface. Then, the polarizing plate can be produced by using the adhesive of both sides. It can be seen that in the process, the specific retardation increasing agent having the light transmittance of the present invention is selected, and the filtration conditions and the extension conditions (residual solvent amount and elongation speed) at the time of producing the cellulose ester film are adjusted, and the contact angle can be effectively controlled. deviation. This is a push It is possible to suppress the movement of the small foreign matter or precipitate to the surface of the film by using a filter condition for effectively removing a small amount of foreign matter or precipitate due to the retardation-increasing agent or by using a relatively rapid extension condition, and it is possible to reduce the deviation of the contact angle.

To further improve the deviation of the aforementioned contact angle, In addition to the DAC, in addition to the DAC, a new insight into the deviation of the contact angle can be reduced by mixing cellulose acetate propionate (also referred to as CAP).

Although this mechanism is not clear, it is speculated to be mixed. a cellulose ester of a heterologous type, and an ethyl sulfonate group and a remaining unsubstituted group (OH group) and a propyl group are coexisted in a specific ratio, and a hydrophilic OH group and a slightly hydrophobic propyl group are present. The balance between the hydrophilicity and the hydrophobicity of the surface of the film is obtained, thereby affecting the affinity with the organic solvent or the plasticizer used in the manufacturing process, so that the surface of the film is smooth, and the deviation of the contact angle can be further reduced.

Further, the aforementioned ethyl sulfhydryl group and the remaining unsubstituted group (OH group) In the coexistence of the three of the propylene groups, it is presumed that the affinity with the PVA-based water paste or the ultraviolet curable adhesive is improved, and the adhesion strength is improved.

1‧‧‧Solution pot

3, 6, 12, 15 ‧ ‧ filters

4, 13‧‧‧ storage pot

5, 14‧‧‧ liquid delivery pump

8, 16‧‧‧ catheter

10‧‧‧Ultraviolet absorber is put into the pot

20‧‧ ‧ Confluence tube

21‧‧‧Mixer

30‧‧‧Pressure die

31‧‧‧Metal strip

32‧‧‧ web

33‧‧‧ peeling position

34‧‧‧Drawing machine extension

35‧‧‧Drying device

41‧‧‧put into the pot

42‧‧‧ Storage pot

43‧‧‧

44‧‧‧Filter

Fig. 1 is a schematic view showing an example of a dosing step, a casting step and a drying step of a preferred solution casting film forming method of the present invention.

[Formation of the Invention]

The cellulose ester film of the present invention contains at least acetamidine A cellulose ester film of a cellulose acetate (resin A) and a retardation increasing agent having a base substitution degree in the range of 2.1 to 2.6, characterized in that the contact angle of the pure water on the surface of the cellulose ester film is 30 to 75° In the range of the contact angle, the standard deviation of 20 points is measured in the film width direction at intervals of 0.05 to 3.0°, and the light transmittance at a wavelength of 320 nm is 80% or more. This feature is a common technical feature of the claims of claim 1 to claim 12. According to the present invention, the PVA-based water paste and the ultraviolet curable adhesive are provided in combination with the polarizing mirror, and have excellent adhesion, and are excellent in film and phase difference exhibitability. Cellulose ester film.

The standard deviation of the aforementioned contact angle is for the film width In the range of 0.05 to 1.5°, the standard deviation of 20 points is measured at equal intervals, and the ductility of the adhesive can be made uniform, and the adhesion by the water paste or the ultraviolet curing type adhesive can be improved, which is more preferable.

Moreover, the mixing ratio of the resin B represented by the above formula 1 is made A cellulose acetate propionate having a degree of substitution of the resin A and the ethyl thiol group in the range of from 1.4 to 2.0 and a degree of substitution of the fluorenyl group of from 0.5 to 1.5 in a range of from 10 to 90% ( Resin B) controls the hydrophilicity and hydrophobicity of the surface of the film from the viewpoint of imparting uniform adhesion by the water paste and the ultraviolet curing type adhesive, and adjusts the hydrophilicity and hydrophobicity of the contact portion of the surface of the film with water. Balance, better. The mixing ratio of the above resin B is more preferably in the range of 20 to 70%.

Further, the total thiol substitution degree of the aforementioned resin A and resin B The absolute value of the difference satisfies the above formula 2, which improves the compatibility of the cellulose esters, the compatibility of the cellulose ester with the retardation increasing agent, reduces the occurrence of minute foreign matter or precipitates, and reduces the standard deviation of the contact angle of the film surface. Therefore, it is better.

The film thickness of the cellulose ester film is in the range of 20 to 38 μm. In this case, the polarizing plate which contributes to the production of a thin film or the liquid crystal display device using the same is thinned, so that it is a preferable range of film thickness.

The retardation value Re of the in-plane direction of the cellulose ester film is In the range of 45 to 60 nm, the retardation value Rth in the film thickness direction is in the range of 110 to 140 nm, which is a preferable range from the viewpoint of optimizing the visibility of the VA mode liquid crystal display device.

The aforementioned retardation-increasing agent has the above general formula (A) The nitrogen-containing heterocyclic compound containing a pyrazole ring or an imidazole ring having a structure is preferably a compound which can impart a desired retardation value and can have a light transmittance of 80% or more measured at a wavelength of 380 nm. Further, the nitrogen-containing heterocyclic compound is excellent in compatibility with a cellulose ester, and can reduce the occurrence of minute foreign matter or precipitates, and can reduce the standard deviation of the contact angle on the surface of the film, and is a particularly preferable compound. The retardation increasing agent is preferably contained in an amount of 0.1 to 5% by mass based on the cellulose ester, and is preferable in exhibiting the effects of the present invention.

A method for producing a cellulose ester film of the present invention, which comprises the steps of dissolving a cellulose ester in a solvent, preparing a dope, and performing filtration. a step of casting a web onto a support for rotating a metal endless belt or a rotating drum by a casting die to form a web, and peeling the web from the support as a film, after peeling off The step of stretching and drying the film, and winding the dried film into a roll, wherein the main solvent is in a range of 1 atm (boiling point + 5 ° C) to (boiling point + 20 ° C) At a temperature, the slurry is filtered using a leaf disk filter, and the residual solvent amount is in the range of 2 to 10% by mass, and the extension speed specified by the above formula 3 is 250 to 500%/min. In the range of stretching, it is possible to effectively remove a small amount of foreign matter or precipitates from the dope, and to suppress the movement of the foreign matter to the surface during stretching, thereby reducing the standard deviation of the contact angle of the film surface, and is a preferable manufacturing method.

The cellulose ester film of the present invention is preferably formed by bonding a water paste to a polarizing plate to form a polarizing plate, or by bonding an ultraviolet curable adhesive to a polarizing plate to form a polarizing plate.

Hereinafter, the present invention and its constituent elements, and aspects and aspects for carrying out the invention will be described in detail. In the present case, "~" is used in the sense that the numerical values described before and after the lower limit value and the upper limit value are included.

<<Overview of the cellulose ester film of the present invention>>

The cellulose ester film of the present invention is a cellulose ester film containing at least a cellulose acetate (resin A) having a degree of substitution of ethyl ketone in the range of 2.1 to 2.6 and a retardation increasing agent, characterized in that the cellulose Pure surface of ester film The contact angle of water is in the range of 30 to 75°, and the contact angle is measured in the film width direction at an equal interval of 20 points with a standard deviation of 0.05 to 3.0°, and the light transmittance of the wavelength of 320 nm is 80. In the case of the PVA-based water paste and the ultraviolet-curable adhesive, it has excellent adhesion and is excellent in film and phase difference exhibitability. Ester film.

The contact angle of the pure water on the surface of the cellulose ester film is When it is in the range of 30 to 75°, the polarizer can be bonded by an adhesive of both the water paste and the ultraviolet curable adhesive.

When the temperature is less than 30°, the hydrophilicity is too high, and when the roll film is formed, The films are easily adhered to each other, and the planarity of the film is deteriorated. When it exceeds 75°, even if it is saponified, the contact angle will not be sufficiently lowered, and the adhesion of the water paste is poor.

Controlling the cellulose ester film of the present invention at the above contact angle The means of the range include, for example, the degree of substitution of the cellulose ester, the adjustment of the amount of the additive represented by the plasticizer, and the like.

Moreover, the aforementioned standard deviation is in the range of 0.05 to 3.0°, Both of the water paste and the ultraviolet curable adhesive are easily spread uniformly, and a preferable variation is obtained from the viewpoint of bonding the polarizer.

When it exceeds 3.0°, water paste and ultraviolet curing adhesive are both The planarity and the adhesion are deteriorated in the following. The lower limit of the deviation is 0.05°, but this is the lower limit of the actually adjustable deviation, and there is no advantage in reducing this deviation.

Controlling the cellulose ester film of the present invention at the above contact angle The means of the range of the deviation, for example, the filtering conditions and extensions described later Conditions (amount of residual solvent, elongation rate), CAP is mixed in a DAC as a resin, and a specific compound or the like as a retardation adjuster is used.

In the present invention, the contact angle defines a value before the saponification treatment, but usually the saponification treatment tends to lower the contact angle. In fact, when the contact angle of the pure water on the surface of the cellulose ester film is in the range of 30 to 75°, the contact angle after the saponification treatment is lowered to about 15 to 45°, and from the viewpoint of obtaining the effect of the present invention, As a result of the experiment, it was confirmed that the effect of the present invention can be effectively obtained by adjusting the contact angle before the saponification treatment to the above range.

Similarly, by performing the saponification treatment, the standard deviation of the contact angle is affected, but in practice, the standard deviation after the saponification treatment is not changed, and the standard deviation of the contact angle before the saponification treatment can be obtained from the viewpoint of obtaining the effect of the present invention. Adjusting to the foregoing range can effectively obtain the effects of the present invention.

Further, in the case of the ultraviolet curable adhesive, there is a hydrophilization treatment such as a corona discharge treatment or a plasma discharge treatment, which is the same as the standard deviation of the contact angle and the contact angle with respect to the saponification treatment, instead of the saponification treatment. Therefore, the effect of the present invention can be obtained by adjusting the contact angle and standard deviation of the surface of the cellulose ester film defined by the present invention.

Moreover, the contact angle measurement of the pure water on the surface of the film was carried out under the environment of a temperature of 23 ° C and a relative humidity of 55%, and the cellulose ester film sample was allowed to stand for 24 hours, and then used in an environment of a temperature of 23 ° C and a relative humidity of 55%. Contact angle meter (made by Concord Interface Science Co., Ltd., trade name DropMaster DM100), 1 μl of pure water was dripped, and the purity was measured after 1 minute. The contact angle of water. The measurement system measures 20 points at equal intervals in the film width direction, removes the maximum value and the minimum value, and uses the average value as the contact angle, and at the same time, finds the standard deviation of the above 20 points.

Moreover, the light transmittance at a wavelength of 320 nm is based on the temperature. At an arbitrary temperature of 23 ° C and a relative humidity of 55%, a light transmittance (%) of a measurement wavelength of 320 nm was measured using an arbitrary spectrophotometer (U-3300 manufactured by Hitachi, Ltd.) at an arbitrary 10 points of the cellulose ester film sample. Value.

<<Cellulose ester>>

The cellulose ester film of the present invention is characterized by containing cellulose acetate (resin A) having an ethyl ketone group substitution degree of from 2.1 to 2.6. When the degree of substitution of the cellulose acetate of the cellulose acetate is less than 2.1, the deterioration of the quality of the film surface may occur due to an increase in the viscosity of the cement. Further, when the degree of substitution of the thiol group is more than 2.6, it is difficult to obtain a necessary retardation value, and the haze is increased due to an increase in the elongation tension.

Here, "the degree of substitution of ethyl thiol" means cellulose ester, The total ratio of the ratio of the hydroxyl groups at the 2, 3, and 6 positions of the glucose unit of the repeating unit to the ethyl hydrazide. Specifically, when all of the hydroxyl groups at the 2, 3, and 6 positions of glucose are 100% esterified, the degree of substitution is the largest 3.

Therefore, in this case, the "degree of substitution" refers to the composition. The sum of the degree of substitution of the thiol group of the plural units of the cellulose ester, expressed as the average of each unit. The degree of substitution of the thiol group described later is also the same.

[Cellulose Acetate (Resin A)]

The cellulose ester film of the present invention is characterized in that cellulose acetate (resin A) having a acetylene group substitution degree of from 2.1 to 2.6 is mainly composed. The term "main component" as used in the present invention means that the cellulose acetate constituting the cellulose ester film is a cellulose acetate having a degree of substitution of an ethyl thiol group of 2.1 to 2.6, and the ratio is 60% by mass or more, preferably 80% by mass or more, and more preferably 95% by mass or more. The average degree of substitution of the ethyl group is in the range of 2.15 to 2.58, and the phase difference exhibitability is also high, and it is preferably used as a retardation film.

The average degree of substitution of the ethyl thiol group in the cellulose acetate can be determined in accordance with ASTM-D817-96.

In the present invention, when the degree of substitution of the ethyl acetate group of the cellulose acetate to be used is within the above range, the effects of the present invention can be exhibited, and the casting property at the time of film formation can be improved, and the use property of the film is excellent. .

Further, the number average molecular weight (Mn) of the cellulose acetate is preferably in the range of 125,000 to 155,000, more preferably in the range of 129000 to 152,000. Further, the weight average molecular weight (Mw) is preferably in the range of 265,000 to 310,000. The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) is preferably in the range of from 1.4 to 2.5, more preferably in the range of from 1.5 to 2.0.

In the present invention, two or more kinds of cellulose acetates may be used in combination.

Weight average molecular weight Mw, number average of cellulose acetate The molecular weight Mn can be measured using gel permeation chromatography (GPC).

The measurement conditions are as follows.

Solvent: dichloromethane

Pipe column: Shodex K806, K805, K803G (Showa Electric (share) system 3 connections)

Column temperature: 25 ° C

Sample concentration: 0.1% by mass

Detector: RI Model 504 (made by GL SCIENCES)

Pump: L6000 (Hitachi Manufacturing Co., Ltd.)

Flow rate: 1.0ml/min

Calibration curve: A calibration curve of 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 500 to 1000000 was used. Thirteen samples were used at approximately equal intervals.

The cellulose acetate of the present invention can be produced by a conventional method such as a sulfuric acid catalyst method, an acetic acid method, a dichloromethane method, or the like, and the raw material is not particularly limited, and examples thereof include cotton linter, wood pulp (from conifers, from Broadleaf trees, kenaf, etc. Further, each of the obtained cellulose acetates can be used in combination at any ratio. Further, the cellulose acetate of the present invention can be synthesized by, for example, the method described in JP-A-H05-45804 and JP-A-2005-281645.

Commercial products of the cellulose acetate (cellulose diacetate) of the present invention include, for example, L20, L30, L40, L50 manufactured by DAICEL, Ca398-3, Ca398 manufactured by Eastman Chemical J Co., Ltd. -6, Ca398-10, Ca398-30, Ca394-60S.

[Cellulose Acetate Propionate (Resin B)]

In the cellulose ester film of the present invention, the mixing ratio of the resin B represented by the following formula 1 is in the range of 10 to 90%, and the degree of substitution of the resin A and the ethyl thiol group containing the cellulose acetate is in the range of 1.4 to 2.0. Cellulose acetate propionate (resin B) having a degree of substitution within the range of 0.5 to 1.5 is preferred.

Formula 1 Resin B mixing ratio = (mass of resin B) / (mass of resin A + mass of resin B) × 100 (%)

Cellulose acetate propionate (resin B) is a mixture of 10% or more, which further reduces the deviation of the contact angle, and exhibits an effect of improving the adhesion of a water paste or an ultraviolet curing type adhesive, within 90%. The mixture can have both the adhesion and the phase difference exhibitability. From the viewpoint of improving the phase difference exhibitability, the mixing ratio of the resin B is more preferably in the range of 20 to 70%, particularly preferably in the range of 30 to 60%. Therefore, as described above, it is presumed that the ethylidene group and the remaining unsubstituted group (OH group) and the propyl group are coexisted in a specific ratio, and the hydrophilic OH group and the slightly hydrophobic propyl group are present. The balance between the hydrophilicity and the hydrophobicity of the surface of the film is obtained, thereby affecting the affinity with the organic solvent or the plasticizer used in the manufacturing process to smooth the surface of the film.

Moreover, cellulose acetate propionate (resin B) is connected Since the resin B is excellent in adhesion to the resin, the resin B is mixed with the resin A to surround the small foreign matter or precipitates caused by the retardation agent present on the surface of the film by the resin B, thereby improving the surface. The effect of the adhesion of the water paste or the ultraviolet curable adhesive of the present invention can also be further improved.

The mixing of the resin B can be carried out in a dope preparation process of a cellulose ester film, or pre-mixed to prepare granules.

The cellulose acetate propionate (resin B) of the present invention has a fluorenyl group having 2 to 4 carbon atoms as a substituent, and the degree of substitution of the ethyl fluorenyl group is X, and when the degree of substitution of the propyl fluorenyl group is Y, It is preferred to satisfy the following formulas (I) to (III).

Formula (I) 2.0≦X+Y≦2.95

Formula (II) 1.4≦X≦2.0

Formula (III) 0.5≦Y≦1.5

Among them, 0.8 ≦ Y ≦ 1.0 is preferable, and from the viewpoint of phase difference exhibitability, 2.2 ≦ X + Y ≦ 2.7 is preferable.

Moreover, it is preferable that the absolute value of the difference of the total thiol substitution degree of the resin A and the resin B satisfies the following formula 2.

Formula 2 | Total thiol substitution of Resin B - Total thiol substitution of Resin A | ≦ 0.3

By mixing cellulose acetate propionate having a total thiol substitution degree close to the total thiol substitution degree of the cellulose acetate of the resin A, the compatibility of the resin with the retardation increasing agent can be improved, and the retardation rise can be improved. Proteolytic resistance of the agent, It can suppress the occurrence of little foreign matter or precipitates.

The number average molecular weight Mn of the above cellulose acetate propionate When it is in the range of 60,000 to 300,000, the mechanical strength of the obtained film becomes strong, which is preferable. More preferably, the number average molecular weight is in the range of 70,000 to 200,000, and when it is within the above range, the precipitation resistance of the additive is improved.

Moreover, the cellulose ester film of the present invention does not hinder the present invention Within the range of effects, it can be used in combination with other resins.

Other resins, such as fibers other than the above cellulose esters Vitamin derivatives (for example, cellulose ester resins, cellulose ether resins, etc.), polycarbonate resins, polystyrene resins, polyfluorene resins, polyester resins, polyarylate resins, Acrylic resin, olefin resin (for example, norbornene resin, cyclic olefin resin, cyclic conjugated diene resin, vinyl alicyclic hydrocarbon resin).

<<Delay riser>>

The term "delay-up agent" as used herein refers to a retardation value Rth (measured at a wavelength of 590 nm) in the thickness direction of a cellulose ester film containing 3 parts by mass of the compound relative to 100 parts by mass of the cellulose ester, as compared with the unadded fiber. The ester film has a compound exhibiting a function of 1.1 times or more.

The retardation increasing agent of the present invention is not particularly limited, and examples thereof can be used. The disc-shaped compound (1,3,5-triazine-based compound) having an aromatic ring described in paragraphs [0143] to [0179] of JP-A-2006-113239, and JP-A-2006- Rod-shaped compound described in paragraphs [0106] to [0112] of the No. 113239, Japan Special Open 2012- In the case of the pyrimidine-based compound described in paragraphs [0118] to [0133], the ultraviolet curable adhesive is used, and when the cellulose ester film of the present invention is bonded, ultraviolet rays which are irradiated by curing are used to hinder the curing reaction. The compound is not suitable for achieving the object of the present invention. Therefore, the cellulose ester film containing the retardation increasing agent in an amount of the retardation value to be exhibited has a light transmittance of 80% or more at a wavelength of 320 nm, which is a property necessary for bonding with a polarizing mirror using an ultraviolet curable adhesive. The light transmittance is preferably 90% or more.

The inventors reviewed the results of the delayed riser in detail and found that The following nitrogen-containing heterocyclic compound satisfies the present invention in that it exhibits phase difference exhibitability, a light transmittance of a cellulose ester film having a wavelength of 320 nm, and a decrease in compatibility with a cellulose ester to reduce the occurrence of a small amount of foreign matter or precipitates. Delayed riser.

[Nitrogen-containing heterocyclic compound]

The delayed riser of the present invention is preferably a nitrogen-containing heterocyclic compound having a structure represented by the general formula (1) described later.

The preferred addition amount is 0.1 to 5 with respect to the cellulose ester. The range of the amount %, in this range, satisfies the phase difference exhibitability, the light transmittance of the cellulose ester film at a wavelength of 320 nm, and the occurrence of a small amount of foreign matter or precipitates by the compatibility with the cellulose ester. The amount of addition is preferably from 1 to 5% by mass, particularly preferably from 2 to 5% by mass. The amount of addition varies depending on the type of the cellulose ester and the type of the compound, but the optimum value of the added amount can be determined according to the desired retardation value of the cellulose ester film of the present invention.

The nitrogen-containing heterocyclic compound is obtained by CH/π with cellulose ester The interaction and control of the hydrogen bonding property of the cellulose ester are characterized by the fact that one compound has both the function of the retardation increasing agent and the wavelength dispersion adjusting agent, and the compatibility with the cellulose ester is excellent, and the manufacturing process is excellent. Little foreign matter or precipitates occur less. For example, a 1,3,5-triazine-based retardation-increasing agent or the like has a weak CH/π interaction, so that the compatibility is slightly inferior, foreign matter is likely to occur, and the foreign matter moves to the surface of the film to increase the contact angle of the present invention. The tendency of deviation.

CH/π interaction refers to hydrogen bonding such as cellulose ester a compatibility site (for example, a hydrogen atom of a hydroxyl group) or a hydrogen bond accepting site (for example, a carbonyl oxygen atom of an ester group) is compatible with an additive, and is present in a hydrogen bonding site of a main chain or a side chain of the resin and an additive. Bonding interaction of π electrons of aromatic compounds. By the CH/π interaction, the above compatibility is excellent.

Use the hydrogen bonding site of the resin (CH of cellulose ester) When π is formed with the additive to form a CH/π interaction, it is of course preferable that the π property of the additive is strong. An example of the intensity of this π-symmetry is an index of a value of NICS (nucleus-independent chemical shift).

This NICS value quantifies aromaticity by magnetic properties. When the ring is aromatic, the center of the ring is strongly shielded by the effect of the ring current, and the anti-masking is reversed when it is non-aromatic (J. Am. Chem. Soc. 1996, 118, 6317). By the magnitude of the NICS value, the intensity of the ring current, that is, the contribution of π electrons to the aromaticity of the ring can be judged. Specifically, it represents a virtual lithium disposed directly in the center of the ring. The chemical shift (calculated value) of the ion. The larger the negative value of this value, the stronger the π property.

There have been several reports on the measured values of the NICS values. example For example, there are reports of measured values, such as Canadian Journal of Chemistry., 2004, 82, 50-69 (Document A) or The Journal of Organic Chemistry., 2000, 67, 1333-1338 (Document B).

Specifically, compared to, for example, a benzene ring (-7.98) or a naphthalene ring ( -8.11) of the aromatic hydrocarbon, pyrrole ring (-14.87), thiophene ring (-14.09), furan ring (-12.42), pyrazole ring (-13.82), or imidazole ring (-13.28), etc. A 6-membered aromatic hydrocarbon ring such as an aromatic heterocyclic ring, a triazole ring (-13.18), an oxadiazole ring (-12.44) or a thiazole ring (-12.82) has a large NICS value and has such an aromatic 5 A compound ring or an aromatic 6-membered ring compound is predicted to enhance the CH/π interaction (indicating the NICS value in parentheses). Among them, a pyrazole ring or an imidazole ring is preferred because it has excellent compatibility with a cellulose ester.

(In the formula, A represents a pyrazole ring or an imidazole ring. Each of Ar ₁ and Ar ₂ represents an aromatic hydrocarbon ring or an aromatic hetero ring, and may have a substituent. R ₁ represents a hydrogen atom, an alkyl group, a fluorenyl group, or a sulfonyl group. , alkoxycarbonyl, or aryloxycarbonyl. q represents an integer from 1 to 2. n and m each represent an integer from 1 to 3.

The aromatic hydrocarbon ring or the aromatic heterocyclic ring represented by Ar ₁ and Ar ₂ is preferably an aromatic hydrocarbon ring or an aromatic heterocyclic ring of 5 or 6 members, for example, a benzene ring, a pyrrole ring, a pyrazole ring, or an imidazole ring. 1,2,3-triazole ring, 1,2,4-triazole ring, tetrazole ring, furan ring, oxazole ring, isoxazole ring, oxadiazole ring, isoxazole ring, thiophene ring , thiazole ring, isothiazole ring, thiadiazole ring, isothiadiazole ring and the like.

5- or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring The substituent has, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or the like), an alkyl group (methyl, ethyl, n-propyl, isopropyl, tert-butyl, n). -octyl, 2-ethylhexyl, etc.), cycloalkyl (cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl, etc.), alkenyl (vinyl, allyl, etc.), cycloolefin a group (2-cyclopenten-1-yl, 2-cyclohexen-1-yl, etc.), an alkynyl group (ethynyl group, propynyl group, etc.), an aromatic hydrocarbon ring group (phenyl group, p-tolyl group, Naphthyl or the like), an aromatic heterocyclic group (2-pyrrolyl, 2-furyl, 2-thienyl, pyrrolyl, imidazolyl, oxazolyl, thiazolyl, benzimidazolyl, benzoxazolyl, 2-benzothiazolyl, pyrazolinone, pyridyl, pyridone, pyrimidinyl, triazinyl, pyrazolyl, 1,2,3-triazole Base, 1,2,4-triazolyl, oxazolyl, isoxazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, thiazolyl, isothiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, etc.), cyano, hydroxy, nitro, carboxy, alkoxy (methoxy, ethoxy, isopropoxy Tert-butoxy , n-octyloxy, 2-methoxyethoxy, etc.), aryloxy (phenoxy, 2-methylphenoxy, 4-tert-butylphenoxy, 3-nitrophenoxy) 2-tetradecylaminophenoxy Base, etc., anthraceneoxy (methyloxy, ethoxycarbonyl, trimethylacetoxy, stearyloxy, benzhydryloxy, p-methoxyphenylcarbonyloxy, etc.) , amine group (amine group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group, etc.), mercaptoamine group (mercaptoamine group, acetamide) Base, trimethylacetamido, laurylamine, benzoylamine, etc., alkyl and arylsulfonylamino (methylsulfonylamino, butylsulfonate) Amino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group, etc., thiol group, alkylthio group (methylthio, ethylthio, n-hexadecylthio, etc.), arylthio (phenylthio, p-chlorophenylthio, m-methoxyphenylthio, etc.) Aminesulfonyl (N-ethylaminesulfonyl, N-(3-dodecyloxypropyl)aminesulfonyl, N,N-dimethylaminesulfonyl, N-ethylidene Aminesulfonyl, N-benzylidenesulfonylsulfonyl, N-(N'-phenylaminecarbamol)sulfonyl, etc., sulfonate, fluorenyl (ethyl sulfhydryl, Trimethyl ethionyl (pivaloyl) benzamidine, etc.) Mercapto (amine, mercapto, N-methylamine, mercapto, N,N-dimethylamine, mercapto, N,N-di-n-octylamine, mercapto, N-(methylsulfonate) Each group such as a mercapto) group such as an aminomethyl group.

Specific examples of R ₁ include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), and an alkyl group (methyl, ethyl, n-propyl, isopropyl, tert-butyl, n). - octyl, 2-ethylhexyl, etc.), anthracenyl (ethenyl, trimethylethylbenzylbenzyl, etc.), sulfonyl (for example, methylsulfonyl, ethylsulfonyl, etc.) And an alkoxycarbonyl group (for example, a methoxycarbonyl group), an aryloxycarbonyl group (for example, a phenoxycarbonyl group, etc.), and the like.

q represents an integer from 1 to 2, and n and m each represent a total of 1 to 3 number.

a compound having the structure represented by the above general formula (1) The molecular weight is not particularly limited, and the smaller the compatibility with the resin, the greater the effect of suppressing the variation of the retardation value of the change in the environmental humidity. Therefore, it is preferably 150 to 2,000, more preferably 200 to 1,500. More preferably 300~1000.

The following shows the general formula (1) used in the present invention. Specific examples of the compound of the structure are shown, but the present invention is not limited to the following specific examples. Further, the following specific examples may be tautomers, and may also form a hydrate, a solvate or a salt.

(Illustration of Compound 1 Synthesis)

Exemplary Compound 1 can be synthesized by the following Scheme .

In 520 ml of dehydrated tetrahydrofuran, 80 g (0.67 mol) of acetophenone and 52 g (0.27 mol) of dimethyl isophthalate were added, and the mixture was cooled in ice water under a nitrogen atmosphere, stirring was continued, and a small amount of sodium decylamine was added dropwise each time. 52.3 g (1.34 mol). After stirring under ice cooling for 3 hours, it was stirred under water cooling for 12 hours. After adding concentrated sulfuric acid to the reaction solution to neutralize, pure water and ethyl acetate were added to carry out liquid separation, and the organic layer was washed with pure water. The organic layer was dried over magnesium sulfate, and the solvent was evaporated to vacuo. To the obtained crude crystals, methanol was added and washed in vacuo to give Intermediate A (55.2 g).

Add intermediate A (55 g, 0.15 mol) to 300 ml of tetrahydrofuran and 200 ml of ethanol, stir at room temperature, and add a little dropwise each time. Hydrazine monohydrate 18.6 g (0.37 mol). After the completion of the dropwise addition, the mixture was heated under reflux for 12 hours. Pure water and ethyl acetate were added to the reaction liquid, and the mixture was separated, and the organic layer was washed with pure water. The organic layer was dried over magnesium sulfate, and the solvent was evaporated. The obtained crude crystals were purified using hydrazine gel chromatography (ethyl acetate / heptane) to give Compound 1 (27 g).

The ¹ H-NMR spectrum of the obtained exemplified compound 1 is shown below. Further, in order to avoid the occurrence of tautomers and to complicate the chemical shift, a few drops of trifluoroacetic acid were added to the measurement solvent, followed by measurement.

¹ H-NMR (400 MHz, solvent: heavy DMSO ((D ₃ c) ₂ S=O), standard: tetramethyl decane) δ (ppm): 8.34 (1H, s), 7.87 to 7.81 (6H, m) , 7.55~7.51 (1H, m), 7.48-7.44 (4H, m), 7.36-7.33 (2H, m), 7.29 (1H, s)

Other exemplary compounds can also be synthesized in the same manner.

<<Other additives>>

The cellulose ester film of the present invention preferably contains other additives, such as a plasticizer, an antioxidant, a light stabilizer, and an antistatic agent, in order to control the contact angle of the film surface with water and to control the standard deviation of the contact angle. , and stripping agents, etc. The compound which is more effective to use preferably contains a plasticizer, and wherein the sugar ester and the polycondensation ester described below are used, and the deviation of the contact angle on the surface of the film is preferably controlled.

[plasticizer] <sugar ester>

The sugar ester used in the present invention is preferably at least one of a pyranose ring or a furanose ring having at least 12 or less, and all or a part of the esterified sugar of the OH group of the structure. ester. The sugar ester used in the present invention may also be preferably added for the purpose of preventing hydrolysis.

The sugar ester used in the present invention contains a furanose ring or a pyranose The compound of at least one of the rings may be a monosaccharide or a polysaccharide having 2 to 12 sugar structures linked thereto. Further, the sugar ester is preferably a compound in which at least one of the OH groups of the sugar structure is esterified. In the sugar ester used in the present invention, the average degree of ester substitution is preferably in the range of from 4.0 to 8.0, more preferably in the range of from 5.0 to 7.5.

The sugar ester used in the present invention is not particularly limited, for example, There is a sugar ester represented by the following general formula (A).

General formula (A)(HO) _m -G-(OC(=O)-R ² ) _n

In the above general formula (A), G represents a residue of a monosaccharide or a disaccharide, R ² represents an aliphatic group or an aromatic group, and m is a total of hydroxyl groups directly bonded to a residue of a monosaccharide or a disaccharide. n is the total of the number of -(OC(=O)-R ² ) groups directly bonded to the residue of the monosaccharide or disaccharide, 3≦m+n≦8, n≠0.

A sugar ester having a structure represented by the general formula (A) is difficult to be isolated by a single compound having a number of hydroxyl groups (m) and a number of (OC(=O)-R ² ) groups (n). There are several compounds in which m and n are different in composition. Therefore, the performance of the mixture in which the number of hydroxyl groups (m) and the number of (OC(=O)-R ² ) groups (n) are each changed is important. In the case of the cellulose ester film of the present invention, the average degree of ester substitution is The sugar ester in the range of 5.0 to 7.5 is preferred.

In the above general formula (A), G represents a monosaccharide or a disaccharide The residue. Specific examples of the monosaccharide include allose, altrose, glucose, mannose, gulose, idose, galactose, teraloose, ribose, arabinose, xylose, and sucrose.

The monosaccharide having the sugar ester represented by the general formula (A) is shown below Specific examples of the compound of the residue are not limited to the compounds exemplified herein.

Further, specific examples of the disaccharide residue include trehalose and sucrose. Maltose, cellobiose, bitter almond, lactose, iso-trehalose, and the like.

The following shows a disaccharide having a sugar ester represented by the general formula (A) Specific examples of the compound of the residue, but the present invention is not limited thereto. Examples of compounds.

In the general formula (A), R ² represents an aliphatic group or an aromatic group. Among them, the aliphatic group and the aromatic group may each independently have a substituent.

Further, in the general formula (A), m is a total of the number of hydroxyl groups directly bonded to a residue of a monosaccharide or a disaccharide, and n is a -(OC(=O) directly bonded to a residue of a monosaccharide or a disaccharide. ) - R ² ) The sum of the numbers. Further, it must be 3 ≦ m + n ≦ 8, preferably 4 ≦ m + n ≦ 8. Also, n≠0. When n is 2 or more, -(OC(=O)-R ² ) groups may be the same or different from each other.

The aliphatic group in the definition of R ² may also be a straight chain, may be a branched chain, or may be a ring shape, preferably a carbon number of 1 to 25, more preferably 1 to 20, and particularly preferably 2 to 2 15 people. Specific examples of the aliphatic group are methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, tert-butyl, pentyl, iso-pentyl, Tert-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, bicyclooctyl, adamantyl, n-fluorenyl, tert-octyl, dodecyl, hexadecyl, Each group such as octadecyl or didecyl.

Further, the aromatic group in the definition of R ² may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group is preferably a carbon number of 6 to 24, more preferably 6 to 12. Specific examples of the aromatic hydrocarbon group include each of benzene, naphthalene, onion, biphenyl, and terphenyl. The aromatic hydrocarbon group is particularly preferably a benzene ring, a naphthalene ring or a biphenyl ring. The aromatic heterocyclic group is preferably a ring containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of the heterocyclic ring are furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, anthracene, oxazole, indole, thiazoline, thiadiazole, oxazoline, Oxazole, oxadiazole, quinoline, isoquinoline, pyridazine, naphthyridine, quinoxaline, quinazoline, porphyrin, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole Each of benzoxazole, benzothiazole, benzotriazole, tetrazaindene, and the like. The aromatic heterocyclic group is particularly preferably a pyridine ring, a triazine ring or a quinoline ring.

Secondly, the general formula (A) represents a preferred sugar ester, for example However, the present invention is not limited to the compounds exemplified herein. The following exemplified compounds, the melting point thereof and the 1% mass reduction temperature Td1 are all within the scope of the present invention.

Sugar esters may also contain more than two differences in one molecule The substituent may contain an aromatic substituent and an aliphatic substituent in one molecule, and may contain two or more aromatic substituents in one molecule, and may contain two or more different ones in one molecule. Aliphatic substituent.

Further, it is preferred to mix two or more types of sugar esters. Better It is a sugar ester having an aromatic substituent and a sugar ester containing an aliphatic substituent.

<Synthesis Example: Synthesis Example of Sugar Ester Represented by General Formula (A)>

An example of the synthesis of a sugar ester which can be applied to the present invention is shown below.

In a four-headed conical flask equipped with a stirring device, a reflux condenser, a thermometer and a nitrogen gas introduction tube, 34.2 g (0.1 mol) of sucrose, 180.8 g (0.8 mol) of benzoic anhydride, and 379.7 g of pyridine were placed, respectively. (4.8 mol), while stirring, the nitrogen gas was bubbled out from the nitrogen gas introduction tube, and the temperature was raised, and the esterification reaction was carried out at 70 ° C for 5 hours. Next, the inside of the Erlenmeyer flask was depressurized to 4 × 10 ² Pa or less, and after distilling off excess pyridine at 60 ° C, the inside of the Erlenmeyer flask was depressurized to 1.3 × 10 Pa or less, and then the temperature was raised to 120 ° C to distill off the benzene. The majority of the anhydride and the resulting benzoic acid. Further, 300 g of a sodium carbonate aqueous solution of 1 L of toluene and 0.5% by mass was added, and the mixture was stirred at 50° C. for 30 minutes, and then allowed to stand, and the toluene layer was separated and taken out. Finally, 100 g of water was added to the separated toluene layer, and the mixture was washed with water at normal temperature for 30 minutes, and then the toluene layer was separated and taken out, and under reduced pressure (4×10 ² Pa or less), toluene was distilled off at 60° C. to obtain a compound A- 1. A mixture of A-2, A-3, A-4 and A-5. After the obtained mixture was analyzed by HPLC and LC-MASS, A-1 was 7% by mass, A-2 was 58% by mass, A-3 was 23% by mass, A-4 was 9% by mass, and A-5 was 3. The mass%, the average ester substitution degree of the sugar ester was 6.57. Further, a part of the obtained mixture was purified by gel column chromatography to obtain A-1, A-2, A-3, A-4 and A-5 having a purity of 100%, respectively.

The sugar ester is added in an amount relative to the cellulose ester. It is preferably added in the range of 0.1 to 20% by mass, and is added in the range of 1 to 15% by mass, and is more preferable from the viewpoint of improving film hardness and film tensile strength.

<polycondensed ester>

A preferred plasticizer for the cellulose ester film of the present invention, for example, contains two A repeating unit of a polycondensation ester obtained by reacting a carboxylic acid with a diol.

The dicarboxylic acid constituting the polycondensation ester is an aromatic dicarboxylic acid, The aliphatic dicarboxylic acid or alicyclic dicarboxylic acid is preferably an aromatic dicarboxylic acid. The dicarboxylic acid may be one type or a mixture of two or more types.

The diol constituting the polycondensation ester is an aromatic diol and a fat The diol or alicyclic diol is preferably an aliphatic diol, more preferably a diol having 1 to 4 carbon atoms. The diol may be one type or a mixture of two or more types.

Wherein, the polycondensation ester is preferably contained to contain at least aromatic The repeating unit obtained by reacting the dicarboxylic acid of the aromatic dicarboxylic acid with the diol having 1 to 4 carbon atoms, more preferably containing the dicarboxylic acid containing the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid and the carbon number 1~ The repeating unit obtained by the diol reaction of 4.

Both ends of the molecule of the polycondensation ester may be blocked or not blocked, but it is preferably blocked from the viewpoint of reducing the moisture permeability of the film.

The polycondensation ester is preferably a compound having a structure represented by the following general formula (2) or (3). In the following formula, n is an integer of 1 or more.

General formula (2) B-(GA) _n -GB

General formula (3) C-(AG) _n -AC

The general formula (2) and (3) A represent a divalent group derived from an alkyl dicarboxylic acid having 3 to 20 carbon atoms (preferably 4 to 12), and a carbon number of 4 to 20 (more) A divalent group derived from an alkenyl dicarboxylic acid of 4 to 12) or a divalent group derived from an aryl dicarboxylic acid having 8 to 20 (preferably 8 to 12) carbon atoms.

A is derived from a stretched alkyl dicarboxylic acid having 3 to 20 carbon atoms. Examples of the divalent group include 1,2-ethanedicarboxylic acid (succinic acid), 1,3-propanedicarboxylic acid (glutaric acid), and 1,4-butanedicarboxylic acid (adipic acid). And a divalent group derived from 1,5-pentanedicarboxylic acid (pimelic acid), 1,8-octanedicarboxylic acid (sebacic acid) or the like. Examples of the divalent group derived from the alkenyldicarboxylic acid having 4 to 20 carbon atoms of A include a divalent group derived from maleic acid, butenedioic acid or the like. An example of a divalent group derived from an aryl dicarboxylic acid having 8 to 20 carbon atoms, and 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzenedicarboxylic acid, 1, A divalent group derived from naphthalene dicarboxylic acid such as 4-benzenedicarboxylic acid or 1,5-naphthalene dicarboxylic acid.

A may be one type or two or more types. its Among them, A is preferably a combination of an alkyl dicarboxylic acid having 4 to 12 carbon atoms and an aryl dicarboxylic acid having 8 to 12 carbon atoms.

The general formula (2) and (3) G represent the number of carbon atoms a divalent group derived from an alkylene glycol of 2 to 20 (preferably 2 to 12), a divalent group derived from an aryl diol having 6 to 20 carbon atoms (preferably 6 to 12), Or a divalent group derived from an alkylene glycol having 4 to 20 (preferably 4 to 12) carbon atoms.

G is derived from an alkyl diol having 2 to 20 carbon atoms. Examples of valencies include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl- 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylene glycol), 2,2-diethyl- 1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dihydroxymethylheptane), 3- methyl- 1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl A divalent group derived from a group such as 1,1-octanediol, 1,9-nonanediol, 1,10-nonanediol, and 1,12-octadecanediol.

G is derived from an aryl diol having 6 to 20 carbon atoms. Examples of valence groups include those derived from 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), and 1,4-dihydroxybenzene (hydroquinone). The 2 price base. G is an example of a divalent group derived from an alkylene glycol having 4 to 12 carbon atoms, and includes diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Derived 2 valence base.

G may be one type or two or more types. its In the above, G is preferably an alkylene glycol having 2 to 12 carbon atoms.

The general formula (2) B is a monocarboxylic acid containing an aromatic ring or A monovalent group derived from an aliphatic monocarboxylic acid.

In the monovalent group derived from a monocarboxylic acid containing an aromatic ring A carboxylic acid containing an aromatic ring in a monocarboxylic acid-containing molecule containing an aromatic ring includes not only an aromatic ring directly bonded to a carboxyl group but also an aromatic ring bonded to a carboxyl group via an alkylene group or the like. Examples of a monovalent group derived from a monocarboxylic acid containing an aromatic ring, including benzoic acid, p-tert-butylbenzoic acid, o-methylbenzoic acid, toluic acid, p-methylbenzene A monovalent group derived from formic acid, dimethylbenzoic acid, ethylbenzoic acid, n-propylbenzoic acid, aminobenzoic acid, ethoxylated benzoic acid, phenylacetic acid, 3-phenylpropionic acid or the like.

An example of a monovalent group derived from an aliphatic monocarboxylic acid, From acetic acid, propionic acid, butyric acid, caprylic acid, caproic acid, citric acid, dodecanoic acid, hard A monovalent group derived from a fatty acid, oleic acid or the like. Among them, a monovalent group derived from an alkyl monocarboxylic acid having an alkyl group having 1 to 3 carbon atoms is preferred, and an ethylidene group (a monovalent group derived from acetic acid) is more preferable.

The general formula (3) C is a monoalcohol or fat containing an aromatic ring. A monovalent group derived from an aliphatic monool.

a monool-containing molecule containing an aromatic ring containing an aromatic ring The alcohol includes not only the direct bond of the aromatic ring and the OH group, but also the bond of the aromatic ring to the OH group via an alkylene group or the like. Examples of the monovalent group derived from a monool containing an aromatic ring include a monovalent group derived from benzyl alcohol, 3-phenylpropanol or the like.

An example of a monovalent group derived from an aliphatic monool, including a Alcohol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isoamyl alcohol, hexanol, isohexanol, cyclohexanol, octanol, isooctanol, 2-ethylhexanol, hydrazine A monovalent group derived from an alcohol, isodecyl alcohol, tert-nonanol, decyl alcohol, dodecanol, dodeca hexanol, dodecanoic alcohol, allyl alcohol, oleyl alcohol or the like. Among them, a monovalent group derived from an alcohol having 1 to 3 carbon atoms such as methanol, ethanol, propanol or isopropanol is preferred.

The weight average molecular weight of the polycondensation ester is preferably The range of 350 to 3000, more preferably the range of 400 to 1500. When the weight average molecular weight is within the above range, the precipitation property of the cellulose ester film of the polycondensation ester used in the present invention is satisfied, and the intended effect can be obtained. The weight average molecular weight can be measured by the aforementioned gel permeation chromatography (GPC).

Specific examples of the polycondensation ester are shown below. First, the table Specific examples of the polycondensation ester at both ends of the "aromatic group" are shown.

Secondly, it means that the two ends are closed by "aliphatic group". Specific examples of the condensed ester.

P-1: from adipic acid / phthalic acid / ethylene glycol (1/1/2 mol Ethyl esterified ester at both ends of the condensate (weight average molecular weight 950)

P-2: an oxime esterified product at both ends of a condensate (weight average molecular weight 2,500) composed of succinic acid/phthalic acid/ethylene glycol/(1/1/2 molar ratio)

P-3: an oxime esterified product at both ends of a condensate (weight average molecular weight 1300) composed of glutaric acid/isophthalic acid/1,3-propanediol (1/1/2 molar ratio)

P-4: from succinic acid / glutaric acid / adipic acid / terephthalic acid / isophthalic acid / ethylene glycol / 1,2-propanediol (1/1/1/1/1/3/2 Mo a propyl esterified body at both ends of a condensate (number average molecular weight 3000) composed of an ear ratio)

P-5: butyl esterified body at both ends of a condensate (weight average molecular weight 2100) composed of succinic acid/phthalic acid/ethylene glycol/(1/1/2 molar ratio)

P-6: 2-ethylhexyl esterification of both ends of a condensate (number average molecular weight 2500) composed of adipic acid/terephthalic acid/1,2-propanediol (1/1/2 molar ratio) body

P-7: a condensate composed of succinic acid/terephthalic acid/poly(average degree of polymerization 5) propylene ether glycol/1,2-propanediol (2/1/1/2 molar ratio) (weight average) 2-ethylhexyl esterified body at both ends of molecular weight 3,500)

P-8: a benzoate formed at both ends of a condensate (weight average molecular weight 490) composed of adipic acid/phthalic acid/1,2-propanediol (3/1/3 molar ratio)

The amount of the polycondensation ester added is preferably in the range of 0.1 to 20% by mass, and is preferably in the range of 1 to 15% by mass based on the cellulose ester, and is more preferable from the viewpoint of improving the film hardness and the film tensile strength.

<Other plasticizers>

Moreover, other examples of plasticizers include polyol esters and polycarboxylates (packages). A phthalate ester, a glycolate compound, a fatty acid ester or a phosphate ester, and the like. These may be used alone or in combination of two or more.

Polyol ester compound is an aliphatic polyol of 2 or more The ester compound (alcohol ester) with a monocarboxylic acid is preferably an aliphatic polyol ester of 2 to 20 members. The polyol ester compound preferably has an aromatic ring or a cycloalkyl ring in the molecule.

Preferred examples of aliphatic polyols include ethylene glycol and diethyl Glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4 -butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, trimethylolpropane, pentaerythritol, trishydroxyl Methyl ethane, xylitol, and the like. Among them, preferred are triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, xylitol and the like.

The monocarboxylic acid is not particularly limited and may be an aliphatic monocarboxylic acid or a fat. A cyclic monocarboxylic acid or an aromatic monocarboxylic acid or the like. In order to improve the moisture permeability of the film and to make it less volatile, an alicyclic monocarboxylic acid or an aromatic monocarboxylic acid is preferred. The monocarboxylic acids may be one kind or a mixture of two or more kinds. Further, all of the OH groups contained in the aliphatic polyol may be esterified or a part may be left in the OH group.

The aliphatic monocarboxylic acid preferably has a linear number of 1 to 32 carbon atoms or Side chain fatty acids. The carbon number of the aliphatic monocarboxylic acid is preferably from 1 to 20, more preferably from 1 to 10. Examples of aliphatic monocarboxylic acids, including acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, capric acid, capric acid, 2-ethyl-hexanoic acid (Hexanoic acid), undecanoic acid , lauric acid, tridecanoic acid (Tridecylic acid), myristic acid, pentadecanoic acid, palmitic acid, seventeen Saturated fatty acids such as acid, stearic acid, lauric acid, arachidic acid, behenic acid, tetracosic acid, waxy acid, octadecanoic acid, montanic acid, tridecanoic acid, tridecanoic acid, etc.; undecene Unsaturated fatty acids such as acid, oleic acid, sorbic acid, linoleic acid, linoleic acid, and arachidonic acid. Among them, in order to improve compatibility with cellulose acetate, acetic acid or a mixture of acetic acid and other monocarboxylic acids is preferred.

An example of an alicyclic monocarboxylic acid comprising cyclopentanecarboxylic acid, cyclohexyl Alkanoic acid, cyclooctanecarboxylic acid, and the like.

An example of an aromatic monocarboxylic acid comprising benzoic acid; in benzoic acid a benzene ring into which one to three alkyl groups or alkoxy groups (for example, a methoxy group or an ethoxy group) are introduced (for example, toluic acid or the like); and an aromatic monocarboxylic acid having two or more benzene rings ( For example, a biphenylcarboxylic acid, a naphthalenecarboxylic acid, a tetrahydronaphthalenecarboxylic acid or the like, preferably benzoic acid.

Specific examples of the polyol ester compound, for example, Japanese special open The compound described in paragraphs [0058] to [0061] of the publication No. 2006-113239.

The polycarboxylic acid ester compound is 2 or more, preferably 2 to 20 An ester compound of a polycarboxylic acid and an alcohol compound. The polyvalent carboxylic acid is preferably a 2 to 20-membered aliphatic polycarboxylic acid or a 3 to 20-membered aromatic polycarboxylic acid or a 3 to 20-membered alicyclic polycarboxylic acid.

Examples of polycarboxylic acids, such as pyromellitic acid, trimesene An aromatic polycarboxylic acid or a derivative thereof having an acid or trimellitic acid of 3 or more, such as succinic acid, adipic acid, sebacic acid, sebacic acid, oxalic acid, and Fumar Acid, maleic acid, tetracarboxylic acid aliphatic polycarboxylic acid, tartaric acid, propanol diacid, malic acid, oxy oxy carboxylic acid, etc., in order to suppress volatilization from the film, preferably Oxypolycarboxylic acid.

An example of an alcohol compound comprising a fat having a linear or side chain A saturated metal compound, an aliphatic unsaturated alcohol compound having a linear or side chain, an alicyclic alcohol compound or an aromatic alcohol compound. The carbon number of the aliphatic saturated alcohol compound or the aliphatic unsaturated alcohol compound is preferably from 1 to 32, more preferably from 1 to 20, still more preferably from 1 to 10. Examples of the alicyclic alcohol compound include cyclopentanol, cyclohexanol and the like. Examples of the aromatic alcohol compound include benzyl alcohol, cinnamyl alcohol and the like.

The molecular weight of the polyvalent carboxylate compound is not particularly limited. It is preferably in the range of 300 to 1000, more preferably in the range of 350 to 750. The molecular weight of the polycarboxylic acid ester-based plasticizer is preferably as large as possible from the viewpoint of suppressing bleeding, and the smaller the moisture permeability or the compatibility with cellulose acetate, the better.

An example of a polycarboxylate compound comprising triethyl citrate Ester, tributyl citrate, ethyltriethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzhydryl tributyl citrate, acetyl sulfonate Phenyl citrate, acetyltribenzyl citrate, dibutyl tartrate, dibutyl butyl tartrate, tributyl trimellitate, tetrabutyl trimellitate, and the like.

The polycarboxylic acid ester compound may be a phthalate compound. Examples of phthalate compounds, including diethyl phthalate, dimethoxy ethyl phthalate, dimethyl phthalate, dioctyl phthalate Ester, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexyl terephthalic acid Ester and the like.

An example of a glycolate compound, including an alkane Phthaphthalic acid alkyl glycolate.

Examples of alkyl phthalic acid alkyl glycol esters, including methyl phthalic acid methyl glycolate, ethyl phthalic acid ethyl glycolate, propyl phthalate Dimethyl propyl glycolate, butyl phthalic acid butyl glycolate, octyl phthalic acid octyl glycolate, methyl phthalic acid ethyl glycolic acid Ester, ethyl phthalic acid methyl glycolate, ethyl phthalic acid propyl glycolate, methyl phthalic acid butyl glycolate, ethyl phthalate Mercaptobutyl butyl glycolate, butyl phthalic acid methyl glycolate, butyl phthalic acid ethyl glycolate, propyl phthalic acid butyl glycolate, Butyl phthalic acid propyl glycolate, methyl phthalic acid octyl glycolate, ethyl phthalic acid octyl glycolate, octyl phthalate Methylglycolate, octyl phthalyl ethyl glycolate or the like is preferably ethyl phthalic acid ethyl glycolate.

Ester compound containing fatty acid ester compound, citric acid esterification a compound or a phosphate compound or the like.

Examples of fatty acid ester compounds, including butyl oleate and ramie Methyl acetate and dibutyl sebacate. Examples of the citrate compound include ethoxylated trimethyl citrate, ethionyl triethyl citrate, and butyl tributyl citrate. An example of a phosphate compound, including triphenylphosphine Acid ester, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate and tributyl phosphate, etc., preferably It is triphenyl phosphate.

Among them, a polyester compound and a glycolate compound are preferred. A compound or a phosphate compound is particularly preferably a polyester compound.

The content of the plasticizer is preferably relative to cellulose acetate. It is in the range of 1 to 20% by mass, more preferably in the range of 1.5 to 15% by mass. When the content of the plasticizer is within the above range, the effect of imparting plasticity can be exhibited, and the bleed resistance of the plasticizer is also excellent, so that the deviation of the contact angle of the film surface can be reduced.

<antioxidant>

Antioxidants are also known as deterioration inhibitors. When the liquid crystal image display device or the like is placed in a state of high humidity and high temperature, the cellulose ester film may be deteriorated.

Antioxidants have, for example, residues in the cellulose ester film The amount of the solvent-retained halogen or phosphoric acid-based plasticizer phosphoric acid or the like is preferable because it is delayed or prevented from decomposing the cellulose ester film.

This antioxidant is preferably a hindered phenolic compound. For example, 2,6-di-t-butyl-p-cresol, pentaerythritol-indole [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], three Ethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di -t-butyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilinyl )-1,3,5-triazine, 2,2-thio-di Ethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyl) Phenyl)propionate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrated cinnamylamine), 1,3,5-trimethyl-2 , 4,6-gin (3,5-di-t-butyl-4-hydroxybenzyl)benzene, gin-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanuramide Acid esters, etc.

Particularly preferred is 2,6-di-t-butyl-p-cresol, pentaerythritol-indole [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethyl Glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate]. Further, a hydrazine-based metal inactive agent such as N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propanyl] hydrazine may be used in combination. A phosphorus-based processing stabilizer such as (2,4-di-t-butyl-phenyl) phosphite.

The amount of such a compound to be added is expressed by mass ratio with respect to the cellulose ester film, and is preferably in the range of 1 ppm to 1.0%, more preferably in the range of 10 to 1000 ppm.

<Microparticles (matting agent)>

The cellulose ester film of the present invention may further contain fine particles (matting agent) in order to improve surface slip properties.

The microparticles may be inorganic microparticles or organic microparticles. Examples of the inorganic fine particles include silica, titania, alumina, zirconia, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium citrate, calcium citrate hydrate, aluminum citrate, Magnesium citrate and calcium phosphate. Among them, cerium oxide or zirconium oxide is preferred, and in order to reduce the haze of the obtained film, it is more preferably cerium oxide.

An example of cerium oxide microparticles, including AEROSIL R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (above is Japan AEROSIL), seahoster KE-P10, KE-P30, KE-P50, KE-P100 (above is Japan) Catalyst (share) system, etc. Among them, AEROSIL R972V, NAX50, seahoster KE-P30, etc. can maintain the low haze of the obtained film and reduce the friction coefficient, which is particularly preferable.

The primary particle diameter of the microparticles is preferably in the range of 5 to 50 nm. More preferably, it is in the range of 7 to 20 nm. When the primary particle diameter is large, the effect of improving the smoothness of the obtained film is large, but the transparency is liable to be lowered. Therefore, the fine particles may contain secondary aggregates having a particle diameter of 0.05 to 0.3 μm. The size of the primary particles of the microparticles or the secondary aggregates thereof can be observed by a type electron microscope at a magnification of 500,000 to 2 million times, and the primary particles or the secondary aggregates, with a particle size of 100 primary particles or secondary aggregates. The average is obtained.

The content of the microparticles is relative to the component containing a low degree of substitution The cellulose acetate as a whole is preferably in the range of 0.05 to 1.0% by mass, more preferably in the range of 0.1 to 0.8% by mass.

<<Manufacturing method of cellulose ester film>>

In the method for producing the cellulose ester film of the present invention, a general expansion method, a T-die method, a calendering method, a cutting method, a casting method, an emulsification method, a hot pressing method, or the like can be used, but the coloring suppression and foreign matter are suppressed. From the viewpoints of suppression of defects, suppression of optical defects such as mold lines, etc., the film formation method may be selected from a solution casting film forming method and a melt casting film forming method, in particular, a solution casting film forming method. A viewpoint of obtaining a uniform smooth surface is preferred.

The following describes the production of the cellulose of the present invention by a solution casting method. An example of the production of an ester film.

The cellulose ester film of the present invention is manufactured by at least The next step is to dissolve the cellulose ester, the nitrogen-containing heterocyclic compound of the retardation increasing agent and the additive in a solvent, prepare a dope, and filter the step, and cast the prepared dope in a strip or a barrel. a step of forming a web on the metal support, peeling the formed web from the metal support, a step of forming the film, a step of stretching and drying the film, and cooling the dried film to form a film Roll-up take-up step. The cellulose ester film of the present invention preferably contains a cellulose ester in a range of from 60 to 95% by mass in the solid content.

Method for producing cellulose ester film of the present invention, characterized by In the foregoing step, the main solvent is filtered at a temperature ranging from 1 atm (boiling point + 5 ° C) to (boiling point + 20 ° C) using a thin disk filter, and the residual solvent is used. The amount is in the range of 2 to 10% by mass, and is extended at an elongation speed of 250 to 500%/min in the film width direction.

By using this manufacturing method, the cellulose ester thin can be reduced The deviation of the contact angle of the film surface improves the ductility of the water paste or the ultraviolet curable adhesive, and achieves uniform adhesion to the polarizer.

The steps are explained below.

(1) Dissolution step

In an organic solvent mainly composed of a good solvent for cellulose ester, the cellulose ester, sometimes the nitrogen-containing heterocyclic compound of the present invention, the sugar ester, the polycondensation ester, and the polysaccharide used in the present invention are dissolved in a pot. The alcohol ester or other compound is stirred while dissolving to form a dope, or the aforementioned nitrogen-containing heterocyclic compound, sugar ester, polycondensate, polyol ester, or other compound solution is mixed with the fiber. The solution of the ester solution forms a dope of the main solution.

The cellulose ester film of the invention is produced by solution casting method In the case of forming an organic solvent usable for the dope, any one which can dissolve the cellulose ester and other compounds at the same time can be used without particular limitation.

For example, a chlorine-based organic solvent may, for example, be dichloromethane. Examples of the non-chlorine organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxoalkane, 1,4-dioxane, cyclohexanone, ethyl formate, and 2 , 2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexa Fluor-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, As the nitroethane or the like, for example, a main solvent is used, and dichloromethane, methyl acetate, ethyl acetate, acetone is preferably used, and particularly preferably dichloromethane or ethyl acetate.

In addition to the above organic solvent, the dope preferably contains A linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40% by mass. When the ratio of the alcohol in the dope becomes high, the web gels and is easily peeled off from the metal support, and when the proportion of the alcohol is small, the cellulose ester promoted in the non-chlorine organic solvent system And other compounds dissolve the function. In the film formation of the cellulose ester film of the present invention, in order to increase the yield The planarity of the cellulose ester film can be applied to a film using a dope having an alcohol concentration of 0.5 to 15.0% by mass.

Especially to make cellulose esters and other compounds in total It is preferred that the dope composition is dissolved in a solvent containing a linear or branched aliphatic alcohol having dichloromethane and a carbon number of 1 to 4 in the range of 15 to 45 mass%.

a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, For example, there are methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol. Among them, methanol and ethanol are preferred from the viewpoints of stability of the dope, lower boiling point, good drying property and the like.

Cellulose ester, nitrogen-containing heterocyclic compound, sugar ester, polycondensation When the ester, the polyol ester, or another compound is dissolved, a method of performing at normal pressure, a method of performing at a boiling point or lower of the main solvent, or a method of pressurizing at a boiling point or higher of the main solvent, or the like may be used. Various methods such as a method of performing a cooling and dissolving method described in Japanese Laid-Open Patent Publication No. Hei 9-95538, and a method of performing high pressure described in JP-A-11-21379, and the like. The dissolution method is particularly preferably a method of pressurizing at a temperature higher than the boiling point of the main solvent.

The concentration of the cellulose ester in the glue is preferably 10 to 40 The range of %. The compound is added to the dope after dissolution or dissolution, and after being dissolved and dispersed, it is filtered and defoamed with a filter medium, and sent to the next step using a liquid-feeding pump.

In the present invention, the filtration of the foregoing glue is carried out in the glue. The main solvent is filtered at a temperature ranging from 1 atm (boiling point + 5 ° C) to (boiling point + 20 ° C) to remove minute foreign matter or precipitate in the paste. It is better.

The preferred temperature range is 45 to 120 ° C, more preferably 45 to 70 °C, and more preferably in the range of 45~55 °C. For example, the boiling point of methylene chloride is 40 ° C at 1 atm. Therefore, it is preferably in the range of 45 to 60 ° C.

Filtration of the glue, preferably with a thin disc filter The main filter 3 filters the dope with, for example, 90% of the filter material having a particle diameter of 10 to 100 times the average particle diameter of the fine particles.

In the present invention, the filter medium used for filtration is an absolute filter The smaller the degree, the better, but the absolute filtration accuracy is too small, and the clogging of the filter material is liable to occur, and the filter material must be frequently replaced, which may cause problems in productivity.

Therefore, in the present invention, the filtration used in the cellulose ester cement The material is preferably a filter having an absolute filtration accuracy of 0.008 mm or less, a range of 0.001 to 0.008 mm, and a filter material having a range of 0.003 to 0.006 mm.

The material of the filter material is not particularly limited, and general filtration can be used. However, a filter material made of a plastic fiber such as a polypropylene or a Teflon (registered trademark) or a metal filter material such as a stainless steel fiber is preferred because it has no fibers falling off.

In the present invention, when the flow rate of filtration of the dope ^{10 ~ 80kg / (h.m 2)} , preferably ^{20 ~ 60kg / (h.m 2)} . Here, when the flow rate of the dope at the time of filtration is 10 kg/(h.m ² ) or more, it becomes efficient productivity, and when the flow rate of the dope at the time of filtration is 80 kg / (h.m ² ) or less, the filter medium It is preferred that the applied pressure is appropriate and the filter material is not damaged.

The filtration pressure is preferably 3,500 kPa or less, more preferably 3000 kPa. The following, more preferably 2,500 kPa or less. The filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.

Figure 1 is a schematic representation of a preferred solution casting film of the present invention. A diagram of an example of a slurry preparation step, a casting step, and a drying step.

The large agglomerates are removed by the filter 44 from the input pan 41, The liquid is supplied to the storage pot 42. Then, various addition liquids are added to the main dope dissolving pot 1 from the storage pot 42.

Then, the main glue is filtered by the main filter 3, by 16 tubes A matting agent dispersion or an ultraviolet absorber addition liquid or the like is added in line.

In most cases, sometimes 10~50 in the main glue Recycled material of mass %.

The recycled material is a finely pulverized cellulose ester film. The material of the cellulose ester film which exceeds the predetermined value of the film, which is formed by cutting the cellulose ester film on both sides of the film, or by scratches or the like.

Moreover, the resin raw material used for the preparation of the glue is preferably used. The cellulose ester and other compounds are granulated in advance.

(2) Casting step (2-1) Casting of glue

The glue is passed through a liquid feeding pump (for example, a pressurized metering gear pump), and the liquid is fed to the pressurizing die 30, and the glue is cast from the die slit to the endless metal support body 31 which is infinitely transferred. Such as stainless steel belt, or spin The step of transferring the casting position on the metal support of the metal cylinder or the like.

a metal support in the casting (casting) step, preferably The surface is mirror-finished, and the metal support is preferably a drum that is plated with a stainless steel strip or cast and whose surface is plated. The casting width is in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, and more preferably in the range of 2 to 2.8 m. The surface temperature of the metal support in the casting step can be set to be -50 ° C to a temperature at which the solvent is not boiled, and more preferably in the range of -30 to 0 ° C. When the temperature is high, the drying speed of the web can be accelerated, but when it is too high, the web will be foamed, and the flatness may be deteriorated. The preferred support temperature is suitably set to 0 to 100 ° C, more preferably 5 to 30 ° C. Alternatively, the web may be gelled by cooling, and a state in which a large amount of residual solvent is contained may be peeled off from the drum. The method of controlling the temperature of the metal support is not particularly limited, and may be, for example, a method of blowing in warm air or cold air, or a method of bringing the back surface of the metal support into warm water. The method of using warm water can effectively carry out heat transfer and shorten the time when the temperature of the metal support reaches a certain temperature, so that it is preferable. When using warm air, it is considered that the temperature of the web is lowered by the latent heat of evaporation of the solvent, and sometimes the warm air above the boiling point of the solvent is used, and the wind having a temperature higher than the target temperature is prevented while being foamed. In particular, it is preferable to carry out drying efficiently by changing the temperature of the support and the temperature of the dry air between casting and peeling.

The shape of the slit of the nozzle portion of the mold can be adjusted to make the film thickness easy A uniform pressurizing die is preferred. The press mold can be used with a coat hanger die or a T die. The surface of the metal support becomes a mirror surface. In order to increase the film forming speed, two or more pressurizing dies may be provided on the metal support, and the amount of the sizing may be divided and overlapped.

(3) Solvent evaporation step

A step of heating the solvent on the casting support by casting the web (the slurry is cast on the casting support, and the formed slurry film is referred to as a web) to evaporate the solvent.

When the solvent is evaporated, there is a method of blowing from the side of the web or from The inside of the support body is heated by liquid, a method of transferring heat from the surface by radiant heat, etc., but the liquid heat transfer method is preferred because of good drying efficiency. Moreover, it is also preferred to use a combination of these methods. Preferably, the web on the cast support is dried on a support under an atmosphere of 40 to 100 ° C. When it is desired to maintain an atmosphere of 40 to 100 ° C, it is preferred to heat the temperature against the top of the web or by means of infrared rays or the like.

From the viewpoints of surface quality, moisture permeability, and peelability, it is preferably The web was peeled off from the support within 30 to 120 seconds.

(4) Stripping step

On the metal support, the solvent is subjected to a step of peeling off the evaporated web at the peeling position. The stripped web is sent as a film to the next step.

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

In addition, the stripping of the web on the metal support at the time of peeling The amount of solvent remaining in the time of leaving is based on the conditions of the drying, the metal support It is preferable to peel in a range of 50 to 120% by mass, etc., and if the web is too soft when the amount of residual solvent is large, the flatness at the time of peeling is impaired, and stickiness due to peeling tension is likely to occur. Even if it is continuous or vertical, in order to have both economic speed and quality, the amount of residual solvent at the time of peeling can be determined.

The amount of residual solvent in the web is defined by the following formula (Z).

Formula (Z) residual solvent amount (%) = (mass before heat treatment of the web - mass after heat treatment of the web) / (mass after heat treatment of the web) × 100

Further, the heat treatment in the case of measuring the amount of residual solvent means heat treatment at 115 ° C for 1 hour.

Peeling tension when peeling metal support and film, usually In the range of 196 to 245 N/m, when wrinkles are likely to occur at the time of peeling, it is preferable to carry out peeling at a tension of 190 N/m or less.

In the present invention, the peeling position on the metal support is The temperature is preferably in the range of -50 to 40 ° C, more preferably in the range of 10 to 40 ° C, and most preferably in the range of 15 to 30 ° C.

(5) Drying and stretching steps

The drying step can also be carried out by dividing into a preliminary drying step and the present drying step.

<Preparation drying step>

The web obtained by peeling off the metal support is dried. Drying of the web allows the web to be conveyed by a plurality of rollers arranged on the upper and lower sides, and at the same time, dried, or, for example, a widened dryer, the both ends of the web are fixed by the clamp while being dried.

The means for drying the web is not particularly limited, and generally can be Drying by hot air, infrared rays, heating rolls, microwaves, etc., is preferably hot air drying from the viewpoint of simplicity.

The drying temperature in the drying step of the web is preferably thin The glass transition temperature of the film is -5 ° C or lower, 100 ° C or higher, and heat treatment is performed for 10 minutes or more and 60 minutes or less, which is effective. The drying temperature is in the range of 100 to 200 ° C, more preferably in the range of 110 to 160 ° C.

<Extension step>

The cellulose ester film of the present invention can control the alignment of molecules in the film by stretching treatment, and can obtain the target retardation values Re and Rth.

The cellulose ester film of the present invention is preferably in the casting direction The extension (also referred to as the MD direction) and/or the width direction (also referred to as the TD direction) is preferably performed by extending the width direction at least by the stretcher extension device.

The extension operation can be divided into multi-stage implementations. Also, carry out double When the shaft is extended, simultaneous biaxial stretching or phased implementation can be performed. In this case, the staged means that, for example, the extension of the extension direction may be sequentially performed, or the extension of the same direction may be divided into multiple stages, and the extension of the different directions may be added to Any of these stages.

That is, for example, the following extension steps can be:

. Casting direction extension→width direction extension→casting direction extension→casting direction extension

. Extending in the width direction → extending in the width direction → extending in the casting direction → extending in the casting direction

Moreover, the simultaneous biaxial stretching also includes a case where the direction is extended and the tension in the other direction is relaxed and contracted.

In particular, the amount of residual solvent at the beginning of the extension is 2 to 10 mass. In the range of %, in the film width direction, the stretching speed expressed by the following formula 3 is extended at a speed of 250 to 500%/min, and the micro foreign matter or precipitate can be extended to inhibit movement and diffusion to the surface of the film. It is preferable to reduce the deviation of the contact angle of the film surface.

The amount of residual solvent at the beginning of the extension affects the extension stress The factor of the size, the larger the amount of residual solvent, the smaller the extension stress becomes, and the small foreign matter or precipitates are easily moved to the surface of the film by stretching, and when the amount of residual solvent is small, the extension stress becomes large, and the extension can be seen. The resulting haze occurs.

When the amount of the residual solvent is 2% by mass or more, the film thickness variation becomes It is preferable from the viewpoint of planarity, and when it is within 10% by mass, the unevenness of the surface is reduced, and the planarity is improved, which is preferable. In the cellulose ester film of the present invention, in order to make the film thickness after stretching into a desired range, in the MD direction and/or the TD direction, preferably in the TD direction, when the glass transition temperature of the film is Tg, (Tg) +15)~(Tg+50)°C temperature range The line extension is better. When the temperature is extended in the above temperature range, the adjustment of the retardation is easy, and the elongation stress is lowered, so that the haze is lowered. Further, it is possible to obtain a cellulose ester film which is excellent in the planarity and the coloring property of the film itself, which suppresses the occurrence of breakage. The extension temperature is preferably in the range of (Tg + 20) to (Tg + 40) °C.

The so-called glass transition temperature Tg refers to the use of commercially available The differential scanning calorimeter was measured at a temperature rising rate of 20 ° C / min, and the intermediate point glass transition temperature (Tmg) determined in accordance with JIS K7121 (1987). The method for measuring the glass transition temperature Tg of the specific cellulose ester film is measured in accordance with JIS K7121 (1987) using a differential scanning calorimeter DSC220 manufactured by Seiko Instruments.

The cellulose ester film of the present invention has a web at least in the TD side It is preferable to extend 1.1 times or more. The extent of the extension is preferably 1.1 to 1.5 times, more preferably 1.2 to 1.4 times, relative to the original width. When it is in the above range, the movement of the molecules in the film is large, and not only the desired retardation value but also the film formation can be formed, and the deviation of the contact angle of the film surface can be reduced.

In order to extend in the MD direction, the peeling force is 130 N/m. It is preferable to perform peeling on the upper side, and particularly preferably 150 to 170 N/m. Since the web after peeling is in a state of a high residual solvent, the tension in the MD direction can be extended by maintaining the same tension as the peeling tension. As the web is dried and the amount of residual solvent is reduced, the elongation in the MD direction is lowered.

The extension ratio in the MD direction can be supported by a belt support The rotation speed is calculated from the running speed of the widening machine.

When extending in the TD direction, for example, there is a Japanese special opening The full-step or part-step drying step shown in the publication No. 62-46625, in which the width of both ends of the web is kept constant by a jig or a needle in the width direction, so that the drying method (referred to as a tenter method) It is preferable to use a widening machine of a jig and a needle widening machine using a needle.

When extending in the TD direction, in the film width direction, the following The extension speed in the range of 250 to 500%/min is extended by the extension 3, and the extension can suppress the movement of small foreign matter or precipitates and spread to the surface of the film, thereby reducing the deviation of the contact angle of the film surface. good. It is speculated that this is when the elongation is extended at a relatively fast speed, and fine foreign matter does not appear on the surface, and after stretching, the standard deviation or unevenness of the contact angle is improved.

Equation 3 Extension speed (%/min) = [(d1/d2)-1] × 100 (%) / t (in the formula 3, d1 is the width dimension of the extending direction of the extended deuterated cellulose film, d2 The width dimension of the aforementioned extension direction of the deuterated cellulose film before extension, t is the time required for the extension (min))

When the stretching speed is 250%/min or more, the flatness can be improved, and the film can be processed at a high speed. Therefore, the viewpoint of production suitability is preferable, and when the film is 500%/min or less, the film can be processed without breaking, which is preferable.

A preferred extension speed is in the range of 300 to 400%/min.

The cellulose ester film of the present invention has a phase difference by extension, but the in-plane retardation value Re and the thickness direction retardation value Rth are based on an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix). Polarimeter: manufactured by Axo Matrix, at 23 ° C. The three-dimensional refractive index measurement was carried out at a wavelength of 590 nm in an environment of 55% RH, and was calculated from the obtained refractive indices nx, ny, and nz.

The cellulose ester film of the present invention is defined by the following formula (i) The retardation value Re of the in-plane direction of the cellulose ester film is in the range of 45 to 60 nm, and the retardation value Rth in the film thickness direction defined by the following formula (ii) is in the range of 110 to 140 nm, and is provided in the VA mode liquid crystal. In the case of a display device, it is preferable from the viewpoint of improving visibility such as viewing angle or contrast. The cellulose ester film can be adjusted within the range of the above retardation value by adjusting the stretching ratio at least in the aforementioned TD direction while stretching.

Formula (i): Re = (n _{x -} n _y ) × d (nm)

Formula (ii): Rth={(n _x +n _y )/2-n _z }×d(nm) (in the formulas (i) and (ii), n _x represents the refractive index in the in-plane direction of the film The refractive index of the largest direction x. n _y represents the refractive index of the direction y orthogonal to the direction x in the in-plane direction of the film. n _z represents the refractive index of the thickness direction z of the film, and d represents the thickness of the film ( Nm)).

<knurling processing>

After the heat treatment or the cooling treatment, it is preferred to provide a cutting blade before the winding, and cut the end portion to obtain a good roll shape. Further, embossing is preferably performed at both end portions of the width.

Embossing can be formed by pressing a heated embossing roll to make. The embossing rolls form fine irregularities, and by pressing them, irregularities are formed on the film, and the ends can be made large.

The embossing at both ends of the width of the retardation film of the present invention The height is preferably 4 to 20 μm and the width is 5 to 20 mm.

Further, in the invention, the embossing process is provided on the film In the film forming step, after the drying is completed, it is preferred before the winding.

(6) Winding step

The amount of the residual solvent in the web is 2% by mass or less, and the film is wound up in the form of a film. By setting the residual solvent amount to 0.4% by mass or less, a film having good dimensional stability can be obtained.

The winding method can be used by a general user. Method, fixed stretching method, taper tension method, program tension control method with constant internal stress, etc., can be used separately.

<Physical properties of cellulose ester film> (haze)

The cellulose ester film of the present invention preferably has a haze of less than 1%, more preferably less than 0.5%, and even more preferably less than 0.3%. The haze is less than 1%, and the transparency of the film becomes higher, which has an advantage that it is easier to use as a film for optical use. Further, the internal haze of the cellulose ester film is preferably less than 0.1, more preferably less than 0.05.

(balanced moisture content)

The cellulose ester film of the present invention has an equilibrium moisture content at 25 ° C and a relative humidity of 60%, preferably 4% or less, more preferably 3% or less. By making peace It is preferable that the water content of the water is set to 4% or less, it is easy to respond to changes in humidity, and optical characteristics or dimensions are less likely to change.

(film length, width, film thickness)

The cellulose ester film of the present invention is preferably a long size, and specifically preferably has a length of about 100 to 10,000 m and is wound into a roll shape. Further, the cellulose ester film of the present invention has a width of preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably 1.4 to 4 m.

The film thickness of the film is thinner and more productive from the display device The viewpoint is preferably in the range of 10 to 38 μm. When the film thickness is 10 μm or more, a certain film strength or phase difference can be exhibited. When the film thickness is 38 μm or less, it can be suitably used to have a desired phase difference, and the polarizing plate and the display device can be made thinner. The film thickness is particularly preferably in the range of 20 to 38 μm from the viewpoint of the production suitability, optical properties, physical properties, storage stability during storage of the roll, and handleability during processing of the polarizing plate.

<Polarizing plate>

In the polarizing plate of the present invention, the cellulose ester film of the present invention is preferably bonded to at least one side of a polarizing mirror by using a water paste or an ultraviolet curable adhesive.

Further, the polarizer is attached to the cellulose ester film When the polyester film or the acrylic film is bonded to the polarizer by using a water paste or an ultraviolet curable adhesive on the surface on the opposite side of the surface, the change in the phase difference of the moisture of the cellulose ester film can be made smaller. The preferred aspect.

The polarizing plate of the present invention is used as a polarizing plate on the identification side When the film on the identification side of the polarizing plate is provided with an antiglare layer or a transparent hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer or the like.

[Polarizer]

The polarizer of the main constituent elements of the polarizing plate of the present invention is an element that allows only light of a polarized surface in a certain direction to pass through. A representative polarizer is known as a polyvinyl alcohol-based polarizing film. The polyvinyl alcohol-based polarizing film has a urinary dyeing of a polyvinyl alcohol-based film and a dyeing of a dichroic dye.

The polarizer can be formed by using an aqueous solution of polyvinyl alcohol. After stretching one side of the shaft, it is dyed, or dyed, and then stretched in one axis, preferably a polarizing lens which is treated with a boron compound for durability treatment. The film thickness of the polarizer is preferably 2 to 30 μm, and particularly preferably 2 to 15 μm.

Moreover, it is preferable to use the Japanese Patent Laid-Open No. 2003-248123 An ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a polymerization degree of 2000 to 4000, and a saponification degree of 99.0 to 99.99 mol% as described in JP-A-2003-342322. Among them, an ethylene-modified polyvinyl alcohol film having a hot water cut-off temperature of 66 to 73 ° C is preferably used. The polarizer using the ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability, and has a small color unevenness, and is particularly suitable for a large liquid crystal display device.

<Laminated film type polarizer>

Further, the polarizing plate of the present invention is preferably a film, and the thickness of the polarizing lens is in the range of 2 to 15 μm, which is particularly preferable from the viewpoint of the strength and film formation of the polarizing plate.

Such a film polarizer is preferably opened in Japan. A laminated film type polarizer is produced by the method described in Japanese Patent No. 4,719, 205, Japanese Patent No. 4,751, 481, and Japanese Patent No. 4,804,589.

An example of this is, for example, the use of the following steps. The laminated film type polarizing film (polarizing laminated film) of the film is preferable because it can reduce the thickness of the entire polarizing plate and is lightweight.

(Manufacturing method of polarizing laminated film)

The method for producing a polarizing laminate film used in the present invention comprises the following steps.

(a) a step of laminating a laminated film by forming a polyvinyl alcohol-based resin layer by dispersing a rubber component on one surface of a base film formed of a thermoplastic resin, and (b) uniaxially stretching the laminated film; The step of extending the stretched film, (c) dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dyed film, and (d) immersing the polyvinyl alcohol-based resin layer of the dyed film in the dyed film In the solution of the crosslinking agent, a polarizing layer is formed to obtain a crosslinking step of the crosslinked film, and (e) a drying step of drying the crosslinked film.

The steps are explained below.

(a) Lamination step

In this step, a film obtained by dispersing (mixing and dispersing) a rubber component in a thermoplastic resin is used as a base film, and a polyvinyl alcohol-based resin layer is formed on one surface to obtain a laminated film.

(1) Substrate film

The thermoplastic resin which is the basis of the base film is preferably a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, and elongation. Specific examples of the thermoplastic resin include, for example, a chain polyolefin resin; a cyclic polyolefin resin; a (meth)acrylic resin; a polyester resin; a cellulose ester resin; and a polycarbonate resin; Polyvinyl alcohol resin; vinyl acetate resin; polyacrylate resin; polyether resin; polyether resin; polyamine resin; polyimine resin; Mixtures or the like, etc.

The rubber component dispersed in the thermoplastic resin has an oak The rubber-elastic resin component is usually uniformly dispersed in the thermoplastic resin as rubber particles. By mixing and dispersing the rubber component, the tensile strength of the base film, particularly the stretched film, can be increased. When the rubber component has a rubber-elastic resin, it is not particularly limited, but from the viewpoint of compatibility with the thermoplastic resin, it is preferably composed of a resin of the same kind or similar to that of the thermoplastic resin to be used.

For example, when the thermoplastic resin is a chain polyolefin resin, The rubber component may be a copolymer of two or more monomers selected from the group consisting of ethylene and an α-olefin. At this time, the content (polymerization ratio) of each monomer constituting the copolymer, It is preferably less than 90% by mass, more preferably less than 80% by mass.

When the thermoplastic resin is a (meth)acrylic resin, From the viewpoint of compatibility, it is preferred to contain a rubber-based acrylic polymer as a rubber component. The acrylic polymer may be a polymer mainly composed of an alkyl acrylate, or may be a single polymer of an alkyl acrylate, or a copolymer of 50% by mass or more of an alkyl acrylate and 50% by mass or less of another monomer.

The amount of the rubber component is preferably a thermoplastic resin 5 to 50% by mass, more preferably 10 to 45% by mass. When the amount of the rubber component is too small, the effect of increasing the tensile strength is not easily obtained. When the amount of the rubber component is too large, the usability of the base film tends to be lowered.

Rubber component to thermoplastic resin dispersion method, no special In the case where a thermoplastic resin and a rubber component (rubber particles) which are separately produced are kneaded by a sand blasting machine or the like, or a method of dispersing or a thermoplastic resin is prepared, a rubber component is prepared in the same reaction container to obtain a rubber component dispersed therein. A reaction mixture method of a thermoplastic resin or the like. The reaction mixing method is advantageous in increasing the degree of dispersion of the rubber component.

(2) Polyvinyl alcohol resin layer

A polyvinyl alcohol-based resin which forms a polyvinyl alcohol-type resin layer, for example, a polyvinyl alcohol resin and its derivative. Examples of the polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, and the like, and examples thereof include a polyvinyl alcohol resin, an olefin such as ethylene or propylene, an unsaturated carboxylic acid such as acrylic acid, methacrylic acid or crotonic acid. Alkyl esters of unsaturated carboxylic acids, acrylamide, etc. are modified. this Among them, a polyvinyl alcohol resin is preferably used.

The polyvinyl alcohol-based resin is preferably a completely saponified product. Saponification The range of the degree is preferably in the range of 80.0 mol% to 100.0 mol%, more preferably in the range of 90.0 to 99.5 mol%, and still more preferably in the range of 94.0 to 99.0 mol%.

In the above polyvinyl alcohol-based resin, if necessary, it may be added. Additives such as plasticizers, surfactants, and the like. As the plasticizer, a polyhydric alcohol, a condensate thereof, or the like can be used, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, polyethylene glycol, and the like. The amount of the additive to be added is not particularly limited, but is preferably 20% by mass or less of the polyvinyl alcohol-based resin.

Applying a polyvinyl alcohol resin solution to the substrate film For the method, for example, a roll coating method such as a wire bar coating method, a reverse roll coating method, a gravure coating method, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or the like, A well-known method such as a spray method. The drying temperature is, for example, in the range of 50 to 200 ° C, preferably in the range of 60 to 150 ° C. The drying time is, for example, in the range of 2 to 20 minutes.

The thickness of the polyvinyl alcohol-based resin layer in the laminated film is It is preferably 3 μm or more and 50 μm or less, more preferably 5 μm or more and 45 μm or less. When it is 3 μm or less, it becomes too thin after stretching, and the dyeability is remarkably deteriorated. When it exceeds 50 μm, the obtained polarizing laminate film becomes thick.

Polyvinyl alcohol-based resin as a polarizer used in the present invention The thickness of the layer is preferably in the range of 2 to 15 μm from the viewpoint of film formation and strength and flexibility as a polarizer.

(b) Extension step

In this step, a step of uniaxially stretching a laminated film comprising a base film and a polyvinyl alcohol-based resin layer to obtain a stretched film is carried out. The stretching ratio of the laminated film can be appropriately selected in accordance with the desired polarizing characteristics, and is preferably in the range of 5 to 17 times, more preferably 5 to 8 times, relative to the original length of the laminated film.

The extension is in the length direction of the laminated film (film transfer side) The longitudinal extension to the extension is preferred. The longitudinal stretching method includes, for example, a method of extending between rollers, a method of compressing and stretching, a method of extending using a stretcher, and the like. The uniaxial stretching is not limited to the longitudinal stretching treatment, and may be oblique stretching or the like.

(c) Dyeing step

This step is a step of dyeing the polyvinyl alcohol resin layer of the stretched film with a dichroic dye to obtain a dyed film. The dichroic dye is, for example, iodine or an organic dye. Organic dyes such as Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Skyblue LG, lemon yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct Skyblue, Direct Fast Orange S, Fast Black and so on. These dichroic substances may be used alone or in combination of two or more.

When iodine is used as a dichroic dye, the dyeing efficiency can be further improved. Therefore, it is preferred to add the iodide to the dye solution containing iodine. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide.

(d) Cross-linking step

In the present step, the polyvinyl alcohol-based resin layer of the dyed film obtained by dyeing with a dichroic dye is subjected to a crosslinking treatment to obtain a crosslinked film having a polyvinyl alcohol-based resin layer as a polarizing mirror layer. The crosslinking step can be carried out, for example, by immersing the dyed film in a solution (crosslinking solution) containing a crosslinking agent. As the crosslinking agent, conventionally known materials can be used. For example, there are a boron compound such as boric acid or borax, or glyoxal or glutaraldehyde. These may be used alone or in combination of two or more.

(e) drying step

The obtained crosslinked film is usually washed and dried. Thereby, a polarizing laminated film can be obtained. Washing can be carried out by immersing the crosslinked film in pure water such as ion-exchanged water or distilled water. The water washing temperature is usually in the range of 3 to 50 ° C, preferably 4 to 20 ° C. The immersion time is usually in the range of 2 to 300 seconds, preferably 5 to 240 seconds. The washing may be carried out by a combination of a washing treatment of an iodide solution and a washing with water, or a solution in which a liquid alcohol such as methanol, ethanol, isopropanol, butanol or propanol is appropriately blended may be used.

The drying method can be any suitable method (for example, natural Dry, air dry, heat and dry). For example, the drying temperature during heating and drying is usually in the range of 20 to 95 ° C, and the drying time is usually 1 to 15 minutes. degree.

The polarizing laminated film system has a dichroic pigment adsorbed and matched The polarizer layer formed of the polyvinyl alcohol-based resin layer itself can be used as a polarizing plate. In a preferred embodiment of the present invention, for example, after the polarizing laminate film is formed by the above steps, the polyvinyl alcohol layer of the polarizing laminate film is peeled off from the base film, and the polyvinyl alcohol layer can be used as the present invention. The invention uses a polarizer. According to the method of the present invention, the thickness of the polarizer layer can be 15 μm or less, so that a thin polarizer can be obtained. Further, the polarizing mirror used in the present invention is also excellent in polarizing performance and durability.

[Production of polarizing plate]

The polarizing plate of the present invention can be produced by a general method. The polarizing lens side of the cellulose ester film of the present invention is subjected to alkali saponification treatment, and at least one surface of the polarizing lens produced by immersion stretching in an iodine solution is preferably adhered using a completely saponified polyvinyl alcohol aqueous solution (water paste). The other side can be attached to other polarizer protective films. When the cellulose ester film of the present invention is used in a liquid crystal display device, it is preferably provided on the liquid crystal cell side of the polarizer, and the film on the outer side of the polarizer can be protected by a conventional polarizing plate.

For example, a conventional polarizing plate protective film is preferably used in the city. Cellulose ester films sold (eg Konicaminolta tac KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC6UY, KC6UA, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC8UX-RHA, KC8UXW-RHA-C, KC8UXW-RHA- NC, KC4UXW-RHA-NC, above Konicaminolta (share) system.

Orientation with the polarizer, such as absorption by a polarizer It is preferred that the axis and the slow axis of the cellulose ester film are orthogonal to each other.

[Ultraviolet hardening type adhesive]

Further, in the polarizing plate of the present invention, the cellulose ester film of the present invention and the polarizer are preferably further provided by an ultraviolet curable adhesive.

In the present invention, the cellulose ester film is bonded to the polarizer, By using an ultraviolet curable adhesive, a polarizing plate having high film strength and excellent planarity can be obtained. In particular, when a polarizing plate protective film of a polyester film type or an acrylic film type is bonded to the other surface, a polarizing plate having high durability against humidity fluctuation can be produced, which is preferable.

<Composition of ultraviolet curing type adhesive>

The ultraviolet curable adhesive composition for a polarizing plate includes, for example, a photoradical polymerization type composition by photoradical polymerization, a photocationic polymerization type composition by photocationic polymerization, and photoradical polymerization and photocationic polymerization in combination. The mixed composition is known.

Photoradical polymerization type composition, for example, Japanese special In JP-A-2008-009329, a radically polymerizable compound containing a polar group such as a hydroxyl group or a carboxyl group, and a radically polymerizable compound containing no polar group are contained in a specific ratio. In particular, the radically polymerizable compound is preferably a compound having a radically polymerizable ethylenically unsaturated bond. Preferred examples of the radically polymerizable compound having an ethylenically unsaturated bond include a compound having a (meth) acrylonitrile group. With (methyl) Examples of the compound of the acrylonitrile group include an N-substituted (meth) acrylamide-based compound, a (meth) acrylate-based compound, and the like. (Meth) acrylamide refers to acrylamide or methacrylamide.

Further, the photocationic polymerization type composition is, for example, a Japanese special Japanese Patent Publication No. 2011-028234, which contains (α) a cationically polymerizable compound, (β) a photocationic polymerization initiator, and (γ), a light sensitizer which exhibits a great absorption for light having a wavelength longer than 380 nm and δ) An ultraviolet curable adhesive composition of each component of a naphthalene-based photo sensitizer. However, an ultraviolet curable adhesive other than these may be used.

(1) Pre-processing steps

The pretreatment step is a step of facilitating the subsequent treatment of the cellulose ester film with the polarizer. It is easy to continue processing such as corona treatment, plasma treatment, and the like.

(coating step of ultraviolet curing type adhesive)

The application step of the ultraviolet curable adhesive is applied to at least one of the surfaces of the polarizer and the cellulose ester film, and the ultraviolet curable adhesive is applied. When the ultraviolet curable adhesive is directly applied to the surface of the polarizer or the cellulose ester film, the coating method is not particularly limited. For example, various wet coating methods such as a doctor blade, a wire bar, a die coater, a notch coater, and a gravure coater can be used. Further, a method in which an ultraviolet curable adhesive is cast between a polarizer and a cellulose ester film, and then uniformly pressed by a roller or the like may be used.

(2) Lamination step

After the ultraviolet curable adhesive is applied by the above method, it is treated in a bonding step. This bonding step, for example, in the previous coating step, when the ultraviolet curable adhesive is applied to the surface of the polarizer, the cellulose ester film is overlapped there. Further, when the ultraviolet curable adhesive is applied to the surface of the cellulose ester film, the polarizer is superposed thereon. Further, when the ultraviolet curable adhesive is cast between the polarizer and the cellulose ester film, the polarizer and the cellulose ester film are overlapped in this state. Usually, in this state, pressurization is performed by a pressure roller or the like on both sides of the cellulose ester film side. The material of the pressure roller can be metal or rubber. The pressure roller disposed on both sides can be the same material or different materials.

(3) Hardening step

The hardening step irradiates the uncured ultraviolet curable adhesive with ultraviolet rays to include a cationically polymerizable compound (for example, an epoxy compound or an oxetane compound) or a radical polymerizable compound (for example, an acrylate system). The ultraviolet curable adhesive of the compound, the acrylamide compound or the like is cured, and the superposed polarizing lens and the cellulose ester film are bonded via an ultraviolet curing adhesive. When the cellulose ester film is bonded to one surface of the polarizer, the active energy ray can be irradiated from either the polarizer side or the cellulose ester film side. Moreover, when the cellulose ester film is bonded to both surfaces of the polarizer, it is advantageous to irradiate the ultraviolet rays in the state in which the cellulose ester film is superposed on both sides of the polarizer via the ultraviolet curable adhesive. The two-side ultraviolet curing type adhesive is simultaneously hardened.

The ultraviolet irradiation conditions may be any suitable conditions as long as they can be used to cure the ultraviolet curable adhesive of the present invention. The amount of ultraviolet rays to be irradiated is expressed by the cumulative amount of light, and is preferably in the range of 50 to 1,500 mJ/cm ² , more preferably in the range of 100 to 500 mJ/cm ² .

When the manufacturing steps of the polarizing plate are carried out in a continuous production line, The production line speed varies depending on the hardening time of the adhesive, and is preferably in the range of 1 to 500 m/min, more preferably in the range of 5 to 300 m/min, and still more preferably in the range of 10 to 100 m/min. When the line speed is 1 m/min or more, it is possible to produce a polarizing plate which can ensure the productivity, can suppress damage to the cellulose ester film, and is excellent in durability. In addition, when the line speed is 500 m/min or less, it is possible to form an ultraviolet curable adhesive layer which is sufficiently hardened by an ultraviolet curable adhesive and has a desired hardness and excellent adhesion.

[Polyester film and acrylic film]

The polyester film or the acrylic film is bonded to the polarizer by using a water paste or an ultraviolet curable adhesive on the surface of the polarizer opposite to the surface to which the cellulose ester film is bonded, thereby obtaining durability against humidity fluctuation. The viewpoint of a high polarizing plate is a preferred aspect. Any of the above-described water paste or ultraviolet curable adhesive can be used for the bonding, but from the viewpoint of the effects of the present invention, an ultraviolet curable adhesive is preferably used.

In the present invention, the outer film (polarizing plate protective film) is A polyester film or an acrylic film having a low moisture permeability, and an inner film (phase difference film) formed of the cellulose ester film of the present invention can be reduced from the outside The influence of moisture is also likely to release the internal moisture. In general, it is presumed that a polarizing plate which improves the durability of the polarizing plate against humidity fluctuation can be obtained.

(1) polyester film

The polyester resin forming the polyester film is not particularly limited, and examples thereof include terephthalic acid, isophthalic acid, phthalic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 1,4. -naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, diphenyl carboxylic acid, diphenoxy ethane dicarboxylic acid, diphenyl hydrazine carboxylic acid, hydrazine dicarboxylic acid, 1,3-cyclopentane Dicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid , succinic acid, 3,3-diethyl succinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyl adipic acid, Dicarboxylic acid of pimelic acid, sebacic acid, dimer acid, sebacic acid, suberic acid, dodecane dicarboxylic acid, ethylene glycol, propylene glycol, hexanediol, neopentyl glycol, 1 , 2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1 a diol such as 6-hexanediol, 2,2-bis(4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)anthracene, or a homopolymer or a dicarboxylic acid formed by a single polycondensation 1 or more acids and 2 or more diols a copolymer obtained by condensation, a copolymer obtained by condensation of two or more kinds of dicarboxylic acids with one or more kinds of diols, and a blended resin obtained by blending two or more kinds of homopolymers or copolymers thereof Any of various polyester resins. Among them, polyethylene terephthalate resin is preferably used. Further, the above resin may be used in combination.

The polyester film is obtained by, for example, melting the above polyester resin It is obtained in the form of a film, a method of cooling and solidifying a film by a casting cylinder, and the like. As the polyester film in the polarizing plate of the present invention, either an unstretched film or an extended film can be used. For example, when a birefringence is required to be small, an unstretched film is suitably used. Further, when birefringence is used for optical compensation of a liquid crystal display device, a stretched film is suitably used. Further, the stretched film, particularly the biaxially stretched film, is suitable for use in terms of strength.

The polyester film is superior in durability to the TAC film. Unlike the TAC film, it is easy to have birefringence. Therefore, when used as a polarizing plate protective film, when viewed obliquely, an uneven rainbow color is produced, and the image quality is lowered.

Therefore, the polyester film preferably has a thickness of 3,000 to 30,000 nm. A polyester film having a retardation value in the in-plane direction. In this case, the polarizing plate protective film disposed on the light-emitting side of the polarizing plate on the light-emitting side is preferably a polyester film having a retardation value of 3,000 to 30,000 nm. Further, the ratio (Re/Rth) of the retardation value Re of the in-plane direction of the polyester film to the retardation value Rth in the thickness direction is preferably 0.200 or more. According to this configuration, at any observation angle, the spectrum of the transmitted light can be approximated by the spectrum of the light source, and good visibility of the color unevenness without the rainbow can be ensured. Further, mechanical strength suitable for thinning can be provided.

This polyester film can use polyethylene terephthalate or Polyethylene naphthalate, but may also contain other copolymerized components. These resins are excellent in transparency and excellent in thermal and mechanical properties, and the retardation value can be easily controlled by stretching processing. In particular, polyethylene terephthalate has a large intrinsic birefringence, and even if the thickness of the film is thin, it is relatively easy to obtain. The large delay value is the most suitable material.

Moreover, the above retardation value can be used to measure the refractive index in the biaxial direction The thickness was determined by using a commercially available automatic birefringence measuring device manufactured by KOBRA-21ADH (Oji Scientific Instruments Co., Ltd.) and Axoscan Co., Ltd. Axoscan.

Polyester film can be made according to the general method of manufacturing polyester film Manufacturing. For example, there is a non-aligned polyester obtained by melting a polyester resin and extruding it into a sheet shape, and at a temperature equal to or higher than the glass transition temperature, by stretching in the longitudinal direction by a speed difference of the rolls, by a tenter A method of applying heat treatment by extending in the lateral direction.

The polyester film used in the present invention may be a one-axis stretch film or A biaxially stretched film, but when the biaxially stretched film is used as a polarizing plate protective film, the color unevenness of the rainbow is not observed when viewed from above the film surface, but when the oblique direction is observed, a rainbow color is sometimes observed. Uneven, so pay attention.

This phenomenon is due to the walking direction and width of the biaxially stretched film. The refractive index ellipsoid having different refractive indices in the thickness direction is formed, and the retardation value in the in-plane direction becomes 0 due to the direction of light transmission inside the film (the refractive index 楕 round body can be regarded as a true circle) The reason for the existence of the direction. Therefore, when the liquid crystal display screen is viewed from a specific direction in the oblique direction, a point where the retardation value in the in-plane direction becomes 0 may occur, and the rainbow-like color unevenness may be concentrically formed around the point. If the angle from the position where the color unevenness of the rainbow is visible from the directly above (normal direction) of the film surface is θ, the angle θ is the larger the birefringence in the plane of the film, The larger the size becomes, the more difficult it is to see the uneven color of the rainbow. Since the biaxially stretched film has a tendency to lower the angle θ, it is preferable that the one-axis stretched film is less likely to see rainbow-like color unevenness.

But a complete one-axis (one-axis symmetry) film, and The mechanical strength in the orthogonal direction of the alignment direction is remarkably lowered, which is not preferable. The polyester film of the present invention does not substantially produce a rainbow-like color unevenness range or a viewing angle range required for a liquid crystal display screen, and does not cause a rainbow-like color unevenness range, and has a biaxial property (two-axis symmetry). .

Maintaining the mechanical strength of the polarizing plate protection film and suppressing the color The means for generating the color unevenness is preferably controlled to a specific range by the ratio of the retardation value Re in the in-plane direction of the polarizing plate protective film to the retardation value Rth in the thickness direction. The smaller the difference between the in-plane retardation and the thickness direction retardation, the more the isotropic effect is caused by the effect of the birefringence of the observation angle, and therefore the change in the retardation of the observation angle becomes small. Therefore, the uneven color of the rainbow due to the observation angle becomes less likely to occur.

Delay value of the in-plane direction of the polyester film used in the present invention The ratio (Re/Rth) of Re to the retardation value Rth in the thickness direction is preferably 0.200 or more, more preferably 0.500 or more, still more preferably 0.600 or more. The larger the ratio (Re/Rth) of the retardation value Re in the in-plane direction to the retardation value Rth in the thickness direction, the more the effect of birefringence is increased, and the rainbow-like color unevenness of the observation angle is less likely to occur. In the case of a completely monoaxial (monoaxially symmetric) film, the ratio (Re/Rth) of the retardation value Re in the in-plane direction to the retardation value Rth in the thickness direction is 2.0. However, as mentioned above, with a nearly monoaxial (axisymmetric) film, the square orthogonal to the alignment direction The mechanical strength of the direction is significantly reduced.

In addition, the in-plane direction of the polyester film used in the present invention The ratio (Re/Rth) of the retardation value Re to the retardation value Rth in the thickness direction is preferably 1.2 or less, more preferably 1.0 or less. In order to completely control the occurrence of rainbow-like color unevenness due to the observation angle, the ratio (Re/Rth) of the retardation value Re and the thickness direction retardation value Rth in the in-plane direction is not necessarily 2.0, and may be 1.2 or less. Moreover, even if the ratio is 1.0 or less, the viewing angle characteristics required by the liquid crystal display device (180 degrees left and right, 120 degrees above and below) may be sufficiently satisfied.

The film forming conditions of the polyester film used in the present invention will be specifically described. In the case of the longitudinal extension temperature and the lateral extension temperature, it is preferably in the range of 80 to 130 ° C, particularly preferably in the range of 90 to 120 ° C. The longitudinal stretching ratio is preferably in the range of 1.0 to 3.5 times, particularly preferably 1.0 to 3.0 times. Further, the lateral stretching ratio is preferably in the range of 2.5 to 6.0 times, particularly preferably 3.0 to 5.5 times. In order to control the retardation value within the above range, it is preferable to control the ratio of the longitudinal stretching ratio to the lateral stretching ratio. When the difference between the extension ratios of the vertical and horizontal directions is too small, it is difficult to increase the retardation value, which is not preferable. Further, setting a low extension temperature is a preferable measure for increasing the delay value. The heat treatment temperature is preferably in the range of 100 to 250 ° C, particularly preferably 180 to 245 ° C.

In order to suppress the variation of the retardation value, it is preferable that the thickness unevenness of the film is small. The extension temperature and the stretching ratio do not have a large influence on the thickness of the film, and therefore the film forming conditions must be optimized from the viewpoint of uneven thickness. In particular, in order to increase the retardation value, when the longitudinal stretch ratio is lowered, the thickness unevenness in the longitudinal direction may be deteriorated. The longitudinal thickness is uneven in a certain range of the stretching ratio There is a region which becomes very poor, and therefore, it is preferable to set the film forming conditions by excluding this range.

The thickness unevenness of the film is preferably 5.0% or less, more preferably 4.5% or less, more preferably 4.0% or less, and particularly preferably 3.0% or less.

As mentioned above, in order to control the retardation value of the film to a specific range In the case of the circumference, it can be carried out by appropriately setting the stretching ratio or the stretching temperature and the thickness of the film. For example, the higher the stretching ratio, the lower the stretching temperature and the thicker the film, the easier it is to obtain a high retardation value. Conversely, the lower the stretching ratio, the higher the stretching temperature, and the thinner the thickness of the film, the easier it is to obtain a low retardation value. However, when the thickness of the film is increased, the retardation value in the thickness direction tends to be large. Therefore, it is preferable that the film thickness is appropriately set in the range described later. Further, in addition to the control of the retardation value, it is necessary to consider the physical properties required for the processing to set the final film forming conditions.

The thickness of the polyester film used in the present invention is arbitrary, but It is preferably in the range of 15 to 300 μm, more preferably in the range of 15 to 200 μm. In the case of a film having a thickness of less than 15 μm, it is also possible in principle to obtain a retardation value of 3000 nm or more. However, at this time, the mechanical properties of the film are remarkably anisotropic, and breakage, cracking, and the like are likely to occur, and the practicality as an industrial material is remarkably lowered. The lower limit of the thickness is particularly 25 μm. When the upper limit of the thickness of the polyester film exceeds 300 μm, the thickness of the polarizing plate becomes too thick, which is not preferable. From the viewpoint of practicality as a polyester film, the upper limit of the thickness is preferably 200 μm. The upper limit of the thickness is particularly 100 μm which is equivalent to that of a general TAC film. Even in the above thickness range, in order to control the retardation value within the range of the present invention, the polyester used as the film substrate is preferably polyparaphenylene. Ethylene diformate.

Various additions can be used in the polyester film used in the present invention. Agent. Other additives include, for example, a plasticizer, an ultraviolet absorber, a fluorine-based surfactant, a release agent, a matting agent, an anti-deterioration agent, an optical anisotropy control agent, an infrared absorber, and the like, and may be suitably used if necessary.

(2) Acrylic film

The acrylic resin contained in the acrylic film means a (meth)acrylic resin, and includes both the concept of an acrylic resin and a methacrylic resin. The acrylic resin will be described below.

Acrylic resin is as described above as (meth)acrylic acid tree Fat refers to a polymer of acrylate or methacrylate. The polymer of methacrylate is preferably composed of a polymer mainly composed of an alkyl methacrylate. The monomer composition of the alkyl methacrylate is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass based on 100% by mass based on the total monomers. The above, and the alkyl methacrylate is 99% by mass or less. Further, the acrylic resin may be a copolymer of 50% by mass or more of a single polymer of an alkyl methacrylate or an alkyl methacrylate and 50% by mass or less of a monomer other than an alkyl methacrylate. The alkyl methacrylate is usually one having a carbon number of from 1 to 4, and preferably methyl methacrylate is used.

Further, a monomer other than an alkyl methacrylate may be a molecule A monofunctional monomer having one polymerizable carbon-carbon double bond or a polyfunctional monomer having two or more polymerizable carbon-carbon double bonds in the molecule. Especially It is preferable to use a monofunctional monomer, for example, an alkyl acrylate such as methyl acrylate or ethyl acrylate, and a styrene monomer such as styrene or alkylstyrene, such as styrene or alkylstyrene, is not affected in the range of the effect of the present invention. An unsaturated nitrile of acrylonitrile or methacrylonitrile. When the alkyl acrylate is used as the copolymerization component, the carbon number is usually from 1 to 8.

Also, the acrylic resin is derived without pentanediamine The compound, the glutaric anhydride derivative, the lactone ring structure and the like are preferred. These acrylic resins may not have sufficient mechanical strength or moist heat resistance in the form of an acrylic resin film.

In the present invention, the content of the organic solvent in the glue can be compared When the drying time is small, the weight average molecular weight (Mw) of the acrylic resin of the present invention is preferably 80,000 or more from the viewpoint of excellent surface properties of the formed film, and the film at the time of lamination can be further improved. From the viewpoint of the planar shape, the weight average molecular weight of the acrylic resin is preferably in the range of 100,000 to 4,000,000.

The upper limit of the weight average molecular weight of acrylic resin, from the stickiness The degree does not become excessive, the solution can be maintained in a suitable manner, and the compatibility with the organic solvent or the additive can be ensured when the dope is prepared, and the upper limit is preferably 4,000,000.

The weight average molecular weight of the acrylic resin used in the present invention, It can be determined by the aforementioned gel permeation chromatography.

In order to improve the softness of the acrylic film, improve the operation Therefore, it is preferred to blend the rubber elastomer particles in the acrylic resin. The rubber elastomer particles are particles containing a rubber elastomer, and may also be rubber-only The particles composed of the body may be particles of a multilayer structure having a layer of a rubber elastomer. Examples of the rubber elastic body include an olefin-based elastic polymer, a diene-based elastic polymer, a styrene-diene-based elastic copolymer, and an acrylic elastomer. Among these, an acrylic elastomeric polymer is preferred from the viewpoint of surface hardness, light resistance, and transparency of the acrylic resin film.

The acrylic elastomeric polymer is preferably an alkyl acrylate. The polymer of the main body may be a single polymer of an alkyl acrylate, or may be a copolymer of 50% by mass or more of an alkyl acrylate and 50% by mass or less of a monomer other than an alkyl acrylate. The alkyl acrylate is usually used in an alkyl group having 4 to 8 carbon atoms. Further, examples of monomers other than alkyl acrylates, such as methyl methacrylate or ethyl methacrylate, styrene monomers such as styrene or alkyl styrene, such as acrylonitrile or a monofunctional monomer such as an unsaturated nitrile of methacrylonitrile, or an ester of an unsaturated carboxylic acid such as allyl (meth)acrylate or methylallyl (meth)acrylate, such as maleic acid a polyfunctional monomer such as a dienic acid of a dibasic acid of an allyl ester, an unsaturated carboxylic acid diester of an ethylene glycol type such as an alkyl diol di(meth) acrylate.

Rubber elastomer particles containing acrylic elastomeric polymer The particles are preferably a layer having a multilayer structure of a layer of an acrylic elastomeric polymer, and may be a two-layer structure having a layer of a polymer mainly composed of an alkyl methacrylate on the side of the acrylic elastomer. Further, it may be a three-layer structure having a layer of a polymer mainly composed of an alkyl methacrylate on the inside of the acrylic elastomer. Further, an example of a monomer composition of a polymer mainly composed of an alkyl methacrylate formed on a layer on the outer side or the inner side of the acrylic elastomer polymer, and a case of the prior acrylic resin The monomer composition of the polymer based on the alkyl acrylate is the same. The acrylic rubber elastomer particles having such a multilayer structure can be produced by a method described in, for example, Japanese Patent Publication No. 55-27576.

Rubber elastomer particles can use the rubber elasticity contained therein The number average volume of the body is 10 to 300 nm. Thereby, when the acrylic resin film is laminated on the polarizing film using an adhesive, it is difficult to peel the acrylic resin film from the adhesive layer. The number average particle diameter of the rubber elastic body is preferably 50 nm or more and 250 nm or less.

The outermost layer is a polymer mainly composed of methyl methacrylate. The rubber elastomer particles containing the acrylic elastomer polymer are mixed with the parent acrylic resin, and the outermost layer of the rubber elastomer particles is mixed with the matrix acrylic resin. Therefore, the acrylic elastomer is dyed by the yttrium oxide in the cross section, and when observed by an electron microscope, the rubber elastomer particles can be observed by removing the particles in the outermost state. Specifically, when a rubber elastomer particle having a two-layer structure in which the inner layer is an acrylic elastomer and the outer layer is a polymer mainly composed of methyl methacrylate is used, it is observed that the acrylic elastomer portion of the inner layer is dyed. The particle morphology of the single layer structure. Further, when the innermost layer is a polymer mainly composed of methyl methacrylate, the intermediate layer is an acrylic elastomer polymer, and the outermost layer is a rubber elastomer particle having a three-layer structure of a polymer mainly composed of methyl methacrylate. It was observed that the central portion of the innermost layer of the particles was not dyed, and only the acrylic elastic polymer portion of the intermediate layer was dyed in the two-layered structure.

Also, in this specification, the average number of rubber elastomer particles Particle size means that rubber elastomer particles are mixed with the matrix resin and the profile is oxidized. In the case of enamel dyeing, the average of the number of diameters of the portion where the almost circular shape is observed is dyed.

In the acrylic film, the blending amount of the rubber elastomer particles is not In particular, it is preferable to blend, for example, 25 to 45% by mass of the rubber elastomer particles having a number average particle diameter of 10 to 300 nm in the transparent acrylic resin.

Acrylic resin can be obtained, for example, by obtaining rubber elastomer particles After that, the monomer which is a raw material of the acrylic resin is polymerized to produce a precursor acrylic resin, and the rubber elastomer particles and the acrylic resin may be obtained by melt-kneading or the like.

The glass transition temperature Tg of the acrylic resin is preferably Within the range of 80~120 °C. Further, the acrylic resin is preferably one having a higher hardness on the surface when the film is formed, and specifically, a pencil hardness (according to a load of 500 g, JIS K5600-5-4) of B or more.

Moreover, the view of acrylic film from the softness of acrylic resin The point is preferably a bending elastic modulus (JIS K7171) of 1,500 MPa or less. The flexural modulus is more preferably 1300 MPa or less, still more preferably 1200 MPa or less. The flexural modulus is changed by the kind or amount of the acrylic resin or the rubber elastomer particles in the acrylic film. For example, when the content of the rubber elastomer particles is larger, the bending elastic modulus generally decreases. Further, the acrylic resin is a copolymer of an alkyl methacrylate and an alkyl acrylate, and the bending elastic modulus is generally small as compared with a single polymer using an alkyl methacrylate.

Further, the rubber elastic particles are formed using the above two-layer structure. In the case of acrylic elastic polymer particles, compared to the use of the above three-layer structure The acrylic elastic polymer particles generally have a small bending elastic modulus, and when a single-layer structure of the acrylic elastic polymer particles is used, the bending elastic modulus generally decreases. Further, in the rubber elastic particles, the smaller the average particle diameter of the rubber elastic body or the larger the amount of the rubber elastic body, the smaller the bending elastic modulus. Therefore, it is preferable to adjust the type or amount of the acrylic resin or the rubber elastomer particles to the above-mentioned predetermined range, and to make the bending elastic modulus 1500 MPa or less.

When the acrylic film is composed of a plurality of layers, the acrylic resin group The layer which may exist other than the layer of the product is not particularly limited, and may be, for example, a layer of an acrylic resin or a composition thereof which does not contain rubber elastomer particles, or a content of rubber elastomer particles or rubber in rubber elastomer particles. The average particle diameter of the elastomer is a layer composed of an acrylic resin other than the above.

Typically, it is composed of 2 layers or 3 layers, for example, The layer of the acrylic resin/the layer of the acrylic resin containing no rubber elastomer particles or a layer thereof is composed of two layers, and may be a layer composed of an acrylic resin composition or an acrylic resin containing no rubber elastomer particles or a composition thereof. The layer of the material/layer of the acrylic resin composition is composed of three layers. In the acrylic film having a multilayer structure, the surface of the layer of the acrylic resin composition may be a bonding surface with a polarizer.

Further, when the acrylic film is composed of a plurality of layers, the rubber elastic body The content of the particles or the layers of the above-mentioned admixture may be different from each other. For example, a layer containing an ultraviolet absorber and/or an infrared ray absorbing agent and a layer containing no ultraviolet absorbing agent and/or an infrared absorbing agent may be laminated. In addition, the content of the ultraviolet absorber of the layer of the acrylic resin composition may be higher than that of the rubber-free bomb. The content of the ultraviolet absorber of the layer of the acrylic resin of the physical particles or the composition thereof is specifically 0.5 to 10% by mass, more preferably 1 to 5% by mass, and the latter is preferably 0 to 1 by mass. More preferably, it is 0 to 0.5% by mass, whereby the color tone of the polarizing plate is not deteriorated, and ultraviolet rays can be effectively blocked, and the degree of polarization during long-term use can be prevented from being lowered.

Acrylic film can be unextended unaligned, or For the extension. When the stretching treatment is not performed, the total thickness of the polarizing plate tends to be thick due to the thick film thickness, but the film thickness is thick, so that the handleability of the acrylic film is improved. Such an acrylic film can be obtained from an unstretched film (raw material film) obtained by forming an acrylic resin composition. Conversely, when stretched, it is easy to exhibit a phase difference, and by stretching, there is an advantage that the film thickness of the acrylic film is thinned while the rigidity is also improved. The stretch film is produced by stretching an unstretched film by any method.

Acrylic resin can be formed by any method, and is not extended. film. The unstretched film is preferably transparent and substantially free of in-plane retardation. The film forming method may be, for example, a solvent casting method in which a molten resin is extruded into a film form, a film forming extrusion molding method, a resin dissolved in an organic solvent is cast onto a flat plate, and a solvent is removed to form a film.

Specific examples of the extrusion molding method, for example, acrylic resin A method of forming a film in a state in which the composition is held by two rolls. At this time, by making the rigidity of the surface of the roller different, one surface of the acrylic resin film can be a slip surface, and the other surface can be a rough surface.

Specific examples of the extrusion molding method, for example, acrylic resin A method of forming a film in a state in which the composition is held by two metal rolls. at this time The metal roll is preferably a mirror roll. Thereby, an unstretched film excellent in surface smoothness can be obtained. Further, when the acrylic film is formed into a multilayer structure, the acrylic resin composition and the other acrylic resin composition may be extruded in a plurality of layers and then formed into a film. Thus, the thickness of the obtained unstretched film is preferably in the range of 5 to 200 μm, more preferably in the range of 10 μm to 85 μm.

<<LCD display device>>

By using a polarizing plate to which the cellulose ester film of the present invention described above is bonded, for a liquid crystal display device, various liquid crystal display devices of the present invention having excellent visibility can be produced.

The polarizing plate of the invention can be used for STN, TN, OCB, A liquid crystal display device of various driving methods such as HAN, VA (MVA, PVA), IPS, OCB, and the like. A VA (MVA, PVA) type liquid crystal display device is preferred.

Liquid crystal display devices usually use a polarizing plate and a back on the identification side. Two polarizing plates of the polarizing plate on the light side, but the polarizing plate of the present invention is preferably used as a polarizing plate of both sides, and can also be used as a polarizing plate of one side. In particular, the polarizing plate of the present invention is preferably used as a polarizing plate that directly contacts the identification side of the external environment. In this case, the cellulose ester film of the present invention is preferably disposed on the liquid crystal cell side in the form of a retardation film.

The bonding direction of the above-mentioned polarizing plate in the VA mode liquid crystal display device can be performed by referring to Japanese Laid-Open Patent Publication No. 2005-234431.

Moreover, the polarizing plate on the backlight side can also be used other than the present invention. In the case of a polarizing plate, for example, a commercially available cellulose ester film (for example, Konica Minolta tacKC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY) is preferably attached to both sides of the polarizer. , KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC2UAH, KC4UAH, KC6UAH, above Konica Minolta (share) system, FUJITAC T40UZ, FUJITAC T60UZ, FUJITAC T80UZ, FUJITAC TD80UL, FUJITAC TD60UL, FUJITAC A polarizing plate of TD40UL, FUJITAC T25TG, FUJITAC T40TG, FUJITAC T25TJ, FUJITAC T40TJ, FUJITAC R02, FUJITAC R06, FUJITAC R032, FUJITAC R033, and the like is Fujifilm.

Moreover, the polarizing plate on the backlight side is preferably used in a polarizer The cellulose ester film of the present invention is used for the liquid crystal cell side, and the polarizing plate of the above-mentioned commercially available cellulose ester film, polyester film, acrylic film, polycarbonate film, or cycloolefin polymer film is bonded to the opposite side. .

By using the polarizing plate of the present invention, especially even if the picture A liquid crystal display device having a large screen of 30 吋 or more can also obtain a liquid crystal display device having excellent visibility such as display unevenness and front contrast.

Moreover, the polarizing plate of the present invention is provided with the liquid crystal display device In addition, it can also be used in an organic electroluminescence display device. For example, the cellulose ester film of the present invention is stretched in a direction oblique to the direction of 45° with respect to the conveyance direction, and is bonded to the roll by a polarizer having an absorption axis in the conveyance direction to form a circularly polarizing plate. Polarizing plate for organic electroluminescent display device At this time, a highly recognizable display device can be obtained.

[Examples]

The invention will be specifically described below by way of examples, but the invention is not limited thereto. In the examples, the expression "parts" or "%" is used, but when there is no special statement, "mass parts" or "% by mass" are indicated.

Example 1

The contents of the cellulose ester used in the examples are shown in Table 1. In the table, DAC: diacetyl cellulose, CAP: cellulose acetate propionate, TAC: triethyl fluorenyl cellulose.

<Production of cellulose ester film> [Production of Cellulose Ester Film 101]

The cellulose ester film 101 was produced in accordance with the method described below.

(modulation of fine particle dispersion dilution)

10 parts by mass of Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter: 7 nm, apparent specific gravity: 50 g/L) and 90 parts by mass of ethanol were stirred and mixed in a dissolver for 30 minutes, and then dispersed using a high-pressure disperser Manton-Gaulin. , modulating the fine particle dispersion.

88 parts by mass of methylene chloride was added to the obtained fine particle dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to be diluted. The obtained solution was filtered with a WOUND CARTRIDGE filter TCW-PPS-1N manufactured by Advantec Toyo Co., Ltd. to obtain a fine particle dispersion diluent.

(modulation of in-line addition liquid)

36 parts by mass of the fine particle dispersion diluted solution prepared above was added to 100 parts by mass of methylene chloride while stirring, and after stirring for further 30 minutes, 6 parts by mass of DAC1 (acetamidyl substitution degree 2.32, weight average molecular weight 27) 10,000) Add while stirring, and stir for another 60 minutes. The obtained solution was filtered through FINE MET NF manufactured by Nippon Seisaku Co., Ltd. to obtain an in-pipe addition liquid. The filter material is used with a nominal filtration accuracy of 20 μm.

(modulation of glue)

The following components were placed in a closed container, and heated and stirred to completely dissolve. The resulting solution is a filter equipped with a thin disk filter, Filtration was carried out at a temperature of 50 ° C (boiling point of dichloromethane + 10 ° C) to obtain a main gum. The filter material is used with a nominal filtration accuracy of 20 μm.

<Composition of main glue>

100 parts by mass of the main dope 1 and 2.5 parts by mass of the in-line addition liquid were thoroughly mixed using an in-line stirrer (Toray static in-line mixer Hi-Mixer, SWJ) to obtain a dope.

(film forming step)

The obtained dope was subjected to a belt casting apparatus, and the final film thickness was set to 33 μm under the conditions of a liquid temperature of 35 ° C and a width of 1.95 m, and uniformly cast onto a stainless steel belt support. On the stainless steel belt support, the organic solvent in the obtained rubber film is evaporated until the residual solvent amount becomes 100% by mass, and after forming the web, the web is stripped by a stainless steel belt support body. from. The obtained web was further dried at 60 ° C for 5 minutes, and after the residual solvent amount was 5% by mass, the web was stretched 1.25 times with respect to the original width in the TD direction at 160 ° C with a stretcher. The extension was carried out at a speed of 300%/min.

After stretching with a widening machine, it is moderated at 130 ° C for 5 minutes. Thereafter, the drying is completed while being conveyed through the drying zone by a plurality of rolls. The drying temperature was 130 ° C, and the conveying tension was set to 100 N/m. The obtained film was cut into a width of 2.0 m, and embossing was applied at both ends of the film to a width of 10 mm and a height of 5 μm. The initial tension was 220 N/m, and the final tension was 110 N/m, and the core was wound around an inner diameter of 15.24 cm. A cellulose ester film 101 having a length of 4000 m and a dry film thickness of 33 μm was obtained.

[Production of cellulose ester film 102~129]

In the production of the cellulose ester film 101, the types and amounts of the retardation-increasing agent, the filtration temperature, the amount of residual solvent, and the elongation rate are shown in Table 2 and Table 3, except for the type of the diacetyl cellulose (DAC2 to DAC4). In addition to the changes shown, cellulose ester films 101 to 129 were also produced.

The structure of the compound 1 to the compound 5 of the comparative retardation increasing agent is shown below.

Using the produced cellulose ester film 101 to 129, the following Evaluation.

<<Evaluation>> <contact angle and standard deviation>

The contact angle measurement of the pure water on the surface of the film was carried out under an atmosphere of a temperature of 23 ° C and a relative humidity of 55%, and the cellulose ester film sample was allowed to stand for 24 hours, and the contact angle was used in an atmosphere having a temperature of 23 ° C and a relative humidity of 55%. The meter (trade name: DropMaster DM100, manufactured by Kyowa Interface Science Co., Ltd.), 1 μl of pure water was dropped, and the contact angle of pure water after 1 minute was measured. The measurement system measures 20 points at equal intervals for the width direction of the film, except The maximum value and the minimum value are taken, and the average value is taken as the contact angle. At the same time, the standard deviation of the above 20 points is obtained.

The standard deviation σ at N=20 is obtained by the following formula.

(N represents the number of samples. x _i represents the respective measured values. m represents the average of the number of N samples).

<Light transmittance measured at a wavelength of 320 nm>

The light transmittance at a wavelength of 320 nm is measured at a temperature of 23 ° C and a relative humidity of 55%. For any 10 points of the sample of the vitamin ester film, a spectrophotometer (U-3300 manufactured by Hitachi High-Tech Fielding) is used for measurement. The light transmittance (%) at a wavelength of 320 nm was averaged.

<delay measurement>

The in-plane retardation value Re and the retardation value Rth in the thickness direction were measured using an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: Axo Matrix) at 23 ° C. The three-dimensional refractive index measurement was carried out at a wavelength of 590 nm in an environment of 55% RH, and the obtained refractive indices nx, ny, and nz were calculated by the following formulas (i) and (ii).

Formula (i): Re = (n _{x -} n _y ) × d (nm)

Formula (ii): Rth={(n _x +n _y )/2-n _z }×d(nm) [In the formulas (i) and (ii), n _x represents the in-plane direction of the film, and the refractive index The refractive index of the largest direction x. n _y represents the refractive index in the direction y orthogonal to the aforementioned direction x in the in-plane direction of the film. n _z represents the refractive index of the film in the thickness direction z, and d represents the thickness (nm) of the film.

<Battery evaluation of water paste> [Production of polarizing plate A101~A129]

The surface of each of the cellulose ester films produced above was subjected to alkali saponification treatment. The mixture was immersed in a sodium hydroxide aqueous solution of 1.5 degrees, and then immersed at 55 ° C for 2 minutes, washed in a water bath at room temperature, and neutralized with a predetermined degree of sulfuric acid at 30 ° C. Again, it was washed in a water bath at room temperature and dried at a temperature of 100 °C.

Next, a roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution, and dried to obtain a polarizing mirror 1 having a thickness of 20 μm. Using a 3% aqueous solution of polyvinyl alcohol (PVA-117H manufactured by Kuraray) as an adhesive, Konica Minolta Tac KC6UA (manufactured by Konica Minolta Co., Ltd.) of the above-mentioned alkali saponified cellulose ester film and the same alkali saponification treatment were prepared. These saponified surfaces are polarized on the side of the polarizer, and the polarizing plates A101 to A129 in which the cellulose ester film, the polarizing mirror 1, and the KC6UA are bonded in this order are obtained. At this time, the MD direction of each cellulose ester film and the slow axis of KC6UA are orthogonal to the absorption axis of the polarizer.

[Subsequent evaluation]

The adhesion of the polarizing plates A101 to A129 was evaluated in accordance with the following criteria.

The operation of peeling off the optical film of the produced polarizing plate by the polarizing mirror was performed 10 times, and the subsequent interface of the optical film/polarizing mirror was visually observed. Thereby, the adhesion of the optical film/polarizer was evaluated on the basis of the following criteria.

◎: 10 times were not completely peeled off

○: Although not completely peeled off, there is a part of peeling off

△: 10 times, 1 to 3 times completely peeled off

×: 10 times, 4 or more times completely peeled off

<Evaluation of the visibility of liquid crystal display device> [Production of Liquid Crystal Display Devices A101~129]

The polarizing plates of the two sides of the SONY 40-type display BRAVIA X1 were peeled off, and the polarizing plates A101 to A129 prepared above were bonded to both sides of the glass surface of the liquid crystal cell by using an acrylic adhesive containing butyl acrylate. .

At this time, the orientation of the polarizing plate is attached to the fiber of the embodiment. The surface of the film of the retinoic ester film was on the liquid crystal cell side, and the absorption axis was oriented in the same direction as the polarizing plate to be bonded in advance, and liquid crystal display devices A101 to A129 corresponding to the polarizing plates A101 to A129 were produced, respectively.

[Identity: Evaluation of comparison]

The azimuth of the display screen when the liquid crystal display device displays a white image is 45° The Y value of the XYZ display system in the direction and the polar angle of 60° was measured by the ELDIM company name "EZ Contrast 160D". Similarly, the Y value of the XYZ display system in the direction of the azimuth angle of 45° and the direction of the polar angle of 60° when the liquid crystal display device displays the black image is measured. Then, from the Y value (YW) in the white image and the Y value (YB) in the black image, the contrast ratio "YW/YB" in the oblique direction is calculated. The measurement of the contrast ratio was carried out in a dark room at a temperature of 23 ° C and a relative humidity of 55%. The azimuth angle of 45° indicates the orientation in which the counterclockwise rotation is 45° when the long side of the display screen is 0° in the plane of the display screen. The polar angle 60° indicates a direction in which the normal direction of the display screen is 0° with respect to the normal line by 60°. The higher the contrast ratio, the higher the contrast, so it is better.

◎: The contrast ratio is 60 or more

○: The contrast ratio is 55 or more and less than 60

△: The contrast ratio is 50 or more and less than 55

×: The contrast ratio is less than 50

<Adhesion evaluation of ultraviolet (UV) hardening type adhesive> [Production of polyester film]

Initially, a polyester film was produced according to the following procedure.

(Manufacturing Example 1 - Polyester A)

The temperature of the esterification reactor was raised, and when it reached 200 ° C, 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added while stirring. 0.017 parts by mass of antimony trioxide as a catalyst, 0.064 parts by mass of magnesium acetate tetrahydrate, and 0.16 parts by mass of triethylamine were added. Subsequently, the temperature was raised by pressurization, and after the pressure esterification reaction was carried out under the conditions of a gauge pressure of 0.34 MPa and 240 ° C, the esterification reaction tank was returned to normal pressure, and 0.014 parts by mass of phosphoric acid was added. After another 15 minutes, the temperature was raised to 260 ° C, and 0.012 parts by mass of trimethyl phosphate was added. Then, after 15 minutes, the dispersion treatment was carried out in a high-pressure disperser, and after 15 minutes, the obtained esterification reaction product was sent to a polycondensation reaction tank, and a polycondensation reaction was carried out at 280 ° C under reduced pressure.

After the end of the polycondensation reaction, cut the particle size by 95% Filtered by a Naslon (NASLON) filter of 5 μm, and extruded into a strand shape from a nozzle, and cooled, solidified, and cut into pellets using cooling water previously subjected to filtration treatment (pore diameter: 1 μm or less). shape. The obtained polyethylene terephthalate resin (A) had an intrinsic viscosity of 0.62 dl/g and substantially contained no inactive particles and internal precipitated particles. (hereinafter referred to as PET (A)).

(Manufacturing Example 2 - Polyester B)

Next, 10 parts by mass of the dry ultraviolet absorber (2,2'-(1,4-phenylene) bis(4H-3,1-benzooxazinone-4-one) is mixed, 90 parts by mass of PET (A) (intrinsic viscosity: 0.62 dl/g) containing particles, and a polyethylene terephthalate resin (B) containing a UV absorber was obtained by using a kneading extruder (hereinafter referred to as PET (B) ).

(Manufacturing Example 3 - Modulation of Adhesive Modified Coating Liquid)

The transesterification reaction and the polycondensation reaction are carried out by a usual method to prepare 46 mol% of terephthalic acid, 46 mol% of isophthalic acid, and isophthalic acid as a dicarboxylic acid component (to the entire dicarboxylic acid component). 5-Sulfoisophthalic acid sodium 8 mol%, water content of diol component (relative to diol component) of ethylene glycol 50 mol% and neopentyl glycol 50 mol% A copolymerized polyester resin of a dispersible sulfonic acid metal base. Next, 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, and then heated and stirred to 77 ° C, the above-mentioned aqueous dispersible sulfonic acid metal was added. After 5 parts by mass of the alkali copolymerized polyester resin was continuously stirred until the resin-free solid, the aqueous resin dispersion liquid was cooled to room temperature to obtain a uniform water-dispersible copolymerized polyester resin liquid having a solid concentration of 5.0% by mass. Further, after dispersing 3 parts by mass of the aggregated cerium oxide particles (manufactured by Fuji-Silysia Co., Ltd., SYLYSIA 310) in 50 parts by mass of water, water dispersion of SYLYSIA 310 was added to 99.46 parts by mass of the water-dispersible copolymerized polyester resin liquid. In an amount of 0.54 parts by mass of the liquid, 20 parts by mass of water was added thereto while stirring to obtain an adhesive modified coating liquid.

(Production of PET film)

90 parts by mass of the particle-free PET (A) resin particles as a raw material for the base film intermediate layer and 10 parts by mass of the PET (B) resin particles containing the ultraviolet absorber were dried under reduced pressure at 135 ° C for 6 hours ( After 1 Torr), it is supplied to the extruder 2 (for the middle layer II layer), Further, PET (A) was dried in a usual manner and then supplied to an extruder 1 (for the outer layer I and the outer layer III), and melted at 285 °C. Each of the two kinds of polymers is filtered by a filter material of a stainless steel sintered body (nominal filtration accuracy: 10% of particles, 95% cut off), and laminated by two types of three-layer bus bars, and formed into a sheet by a nozzle, and then used. In the electrostatic casting method, a casting drum having a surface temperature of 30 ° C was wound and cooled to solidify to form an unstretched film. At this time, the ratio of the thicknesses of the I layer, the II layer, and the III layer was set to 10:80:10 to adjust the discharge amount of each extruder.

Next, a reverse roll method thereto does not extend on both sides of the PET film, so that the coating amount after drying 0.096g / m ² Subsequently to applying the coating solution of the modified, dried at 80 ℃ at 20 seconds.

Introducing the unstretched film forming the coating layer into the stretched extension In the machine, the end of the film was held by a jig, and a hot air zone of a temperature of 125 ° C was introduced at the same time, and extended 4.0 times in the width direction. Subsequently, the width in the width direction was maintained, the temperature was treated at 225 ° C for 30 seconds, and the 3% relaxation treatment was carried out in the width direction to obtain a one-axis alignment PET film having a film thickness of 60 μm.

(Modulation of ultraviolet curing type adhesive liquid 1)

After mixing the following components, the ultraviolet curable adhesive liquid 1 was prepared by defoaming. Further, the triarylsulfonium hexafluorophosphate was formulated in the form of a 50% propylene carbonate solution, and the solid content of triarylsulfonium hexafluorophosphate was shown below.

[Production of polarizing plate B101~B129]

Polarizing plates B101 to B129 were produced in accordance with the following methods.

First, a corona discharge treatment was applied to the surface of the cellulose ester film of the above embodiment. The conditions of the corona discharge treatment were a corona output intensity of 2.0 kW and a line speed of 18 m/min. Then, the ultraviolet curable adhesive liquid 1 prepared as described above was applied onto the corona discharge treated surface of the cellulose ester film by a bar coater to have a film thickness after curing of about 3 μm to form an ultraviolet curable adhesive layer. The polarizing lens 1 produced above was bonded to the obtained ultraviolet curable adhesive layer.

Next, the polyester film produced above was subjected to a corona discharge treatment. The conditions of the corona treatment were a corona output intensity of 2.0 kW and a line speed of 18 m/min.

Then, the ultraviolet curable adhesive liquid 1 prepared as described above was applied onto the corona discharge treated surface of the polyester film by a bar coater to have a film thickness after curing of about 3 μm to form an ultraviolet curable adhesive layer.

a polarizer to which the above cellulose ester film is laminated on one side The polarizing plates B101 to B129 in which a cellulose ester film/ultraviolet curing type adhesive layer/polarizer/ultraviolet curing type adhesive layer/polyester film are laminated are obtained by bonding to the ultraviolet curable adhesive layer. At this time, the slow axis of the cellulose ester film and the polyester film and the absorption axis of the polarizer are orthogonal to each other.

On the side of the cellulose ester film of the laminate, an ultraviolet irradiation device with a conveyor belt (light using a D bulb manufactured by Heraeus Noblelight Fusion UV Systems Co., Ltd.) was used, and the cumulative amount of light was 750 mJ/cm ² to irradiate ultraviolet rays to cause ultraviolet curing. The layer of the agent is hardened to prepare polarizing plates B101 to B129.

[Subsequent evaluation]

The adhesion of the polarizing plates B101 to B129 was evaluated based on the following criteria.

The operation of peeling off the optical film of the produced polarizing plate by the polarizing mirror was performed 10 times, and the subsequent interface of the optical film/polarizing mirror was visually observed. Thereby, the adhesion of the optical film/polarizer was evaluated on the basis of the following criteria.

◎: 10 times were not completely peeled off

○: Although not completely peeled off, there is a part of peeling off

△: 10 times, 1 to 2 times completely peeled off

×: 10 times, 3 or more times completely peeled off

The composition of the cellulose ester film and the evaluation results obtained are shown in Tables 2 and 3 below.

From the results of Tables 2 and 3, the composition of the present invention is satisfied. The cellulose ester films 101 to 107, 110, 111, and 113 to 122, which are excellent in adhesion to both the PVA-based water paste and the ultraviolet-curable adhesive, and the retardation values Re and Rth, are bonded to the polarizer. Since it is suitable for the range of the value of the VA mode liquid crystal display device, the visibility is good.

However, filtration temperature, residual solvent amount, elongation rate, etc. The cellulose ester films 108 and 109 produced under the conditions outside the preferred range of the present invention have a large standard deviation of the contact angle and are inferior to the polarizer.

Further, the retarder is a cellulose ester of a comparative compound. The films 123 to 127 have a low light transmittance at a wavelength of 320 nm, and particularly have poor adhesion when an ultraviolet curable adhesive is used. Further, the cellulose ester films 123 to 125 having a low retardation value have a low contrast and are poor in visibility.

Also, cellulose esters use fibers of lower substitution DAC The ester film 112 has poor adhesion to the polarizer, and the cellulose ester film 128 of TAC is used, and the adhesion to the polarizer is poor, and the retardation value is low even if it is extended. Therefore, the contrast of the liquid crystal display device is low and the visibility is low. Also bad. The cellulose ester used was a DAC, and the cellulose ester film 129 which did not use a retardation-increasing agent was inferior to the polarizer, and the retardation value was low. Therefore, the contrast of the liquid crystal display device was low, and the visibility was also poor.

Example 2 [Production of Cellulose Ester Film 201]

The cellulose ester film 201 produced in the following manner.

(modulation of glue)

The following components were placed in a closed container, and heated and stirred to completely dissolve. The resulting solution was filtered through a filter equipped with a thin disk filter at a temperature of 50 ° C (boiling point of dichloromethane + 10 ° C) to obtain a main dope. The filter material is used with a nominal filtration accuracy of 20 μm.

<Composition of main glue>

100 parts by mass of the main dope 1 and the in-pipe addition liquid prepared in Example 1 were thoroughly mixed using an in-line mixer (Toray static in-line mixer Hi-Mixer, SWJ) to obtain a dope. .

(film forming step)

The obtained dope was subjected to a belt casting apparatus, and the final film thickness was set to 33 μm under the conditions of a liquid temperature of 35 ° C and a width of 1.95 m, and uniformly cast onto a stainless steel belt support. On the stainless steel belt support, the organic solvent in the obtained dope film was evaporated until the residual solvent amount became 100% by mass, and after forming the web, the web was peeled off from the stainless steel belt support. The obtained web was further dried at 50 ° C for 3 minutes so that the residual solvent amount was 10% by mass, and then the web was stretched 1.4 times with respect to the original width in the TD direction at 160 ° C with a stretcher. The extension was carried out at a speed of 300%/min.

After stretching with a widening machine, it is moderated at 130 ° C for 5 minutes. Thereafter, the drying is completed while being conveyed through the drying zone by a plurality of rolls. The drying temperature was 130 ° C, and the conveying tension was set to 100 N/m. The obtained film was cut into a width of 2.0 m, and embossing was applied at both ends of the film to a width of 10 mm and a height of 5 μm. The initial tension was 220 N/m, and the final tension was 110 N/m, and the core was wound around an inner diameter of 15.24 cm. A cellulose ester film 201 having a length of 4000 m and a dry film thickness of 25 μm was obtained.

[Production of cellulose ester film 202~224]

In the production of the above cellulose ester film 201, in addition to the type of diacetyl cellulose (DAC) (DAC2 to DAC4), the type of cellulose acetate propionate (CAP) (CAP1 to CAP3), DAC/ Mixing and mixing ratio of CAP, mixing of DAC/triethyl cellulose (TAC), The mixture of CAP1/CAP2 and the film thickness were changed as shown in Table 4, and cellulose ester films 202 to 224 were also produced.

Using the cellulose ester film produced above, carried out and implemented The same evaluation as in Example 1 is shown in Table 4.

It is known from Table 4 that the mixing ratio of the resin B represented by Formula 1 is obtained. The film thickness of the cellulose ester films 201 to 209, 211, 212, 215, and 216 containing the resin A (DAC) and the resin B (CAP) was 25 μm in the range of 10 to 90%, which was produced in comparison with Example 1. The film is more film-like, but it is excellent in adhesion to a polarizer, and has a high retardation value, and is excellent in visibility of a liquid crystal display device.

Further, cellulose which changes the film thickness of the cellulose ester film As a result of evaluation of the ester film 218 to 224, when the film thickness was in the range of 20 to 38 μm, the retardation value, the adhesion to the polarizer, and the visibility of the liquid crystal display device were excellent.

In this regard, the cellulose ester film 210 used by CAP alone, A cellulose ester film 213 in which TAC and CAP are mixed, a cellulose ester film 214 in which two types of CAP having different degrees of substitution are mixed, and a cellulose ester film 217 in which DAC and TAC are mixed are delayed, adhered to a polarizer, and distinguished. Each item is poor.

[Industrial availability]

When the cellulose ester film of the present invention is bonded to a polarizer, it has excellent adhesion to both the PVA-based water paste and the ultraviolet-curable adhesive, and is a cellulose ester film excellent in film and phase difference exhibitability. A display device such as a polarizing plate, a liquid crystal display device, or an organic electroluminescence display device.

Claims (11)

A cellulose ester film which is a cellulose ester film containing at least cellulose acetate (resin A) having a degree of substitution of ethyl ketone in the range of 2.1 to 2.6 and a retardation increasing agent, characterized in that the cellulose ester film The contact angle of the pure water on the surface is in the range of 30 to 75°, and the standard deviation of the contact angle at 20 o'clock in the width direction of the film is in the range of 0.05 to 3.0°, and is at a wavelength of 320 nm. The light transmittance is 80% or more, and the retardation increasing agent is a nitrogen-containing heterocyclic compound having a structure represented by the following general formula (1). (Wherein, A represents a pyrazole ring or an imidazole ring, Ar ₁ and Ar ₂ each represent an aromatic hydrocarbon ring or aromatic heterocycle may have a substituent group, R ₁ represents a hydrogen atom, an alkyl, acyl, sulfo acyl , alkoxycarbonyl, or aryloxycarbonyl, q represents an integer from 1 to 2, and n and m each represent an integer from 1 to 3. The cellulose ester film according to claim 1, wherein the contact angle is within a range of 0.05 to 1.5° when the contact angle is measured at 20 points at equal intervals in the film width direction. The cellulose ester film according to the first aspect of the invention, wherein the mixing ratio of the resin B represented by the following formula 1 is in the range of 10 to 90%, and the degree of substitution of the resin A and the ethyl thiol group is 1.4 to 2.0. a cellulose acetate propionate (resin B) in the range of 0.5 to 1.5 in the range of 0.5 to 1.5, The mixing ratio of the resin of Formula 1 = (mass of Resin B) / (mass of Resin A + Mass of Resin B) × 100 (%). The cellulose ester film of claim 3, wherein the mixing ratio of the resin B is in the range of 20 to 70%. The cellulose ester film according to claim 3, wherein the absolute value of the difference in the total thiol substitution degree of the resin A and the resin B satisfies the following formula 2, the total thiol substitution degree of the resin B - the resin The total thiol substitution degree of A is ≦0.3. The cellulose ester film according to claim 1, wherein the cellulose ester film has a film thickness of from 20 to 38 μm. The cellulose ester film according to the first aspect of the invention, wherein the retardation value Re of the in-plane direction of the cellulose ester film represented by the following formula (i) is in the range of 45 to 60 nm, and the following formula (ii) is represented by the following formula (ii); The retardation value Rth in the film thickness direction is in the range of 110 to 140 nm, and the formula (i): Re = (n _{x -} n _y ) × d (nm) Formula (ii): Rth = {(n _x + n _y ) /2-n _z } × d (nm) (in the formula (i) and the formula (ii), n _x represents a refractive index in the in-plane direction of the film, the refractive index becomes the maximum direction x, and n _y represents the film In the in-plane direction, the refractive index in the direction y orthogonal to the direction x, n _z represents the refractive index in the thickness direction z of the film, and d represents the thickness (nm) of the film. The cellulose ester film according to claim 1, wherein the retardation increasing agent contains a ratio of 0.1 to 5% by mass based on the cellulose ester. A method for producing a cellulose ester film, which is manufactured as an application The method for producing a cellulose ester film of a cellulose ester film according to any one of the items 1 to 8, which has the following steps: a step of dissolving a cellulose ester in a solvent, preparing a dope, and performing filtration, a casting die for casting a cement onto a support body for rotationally driving a metal endless belt or a rotating drum to form a web, wherein the web is peeled off from the support body as a film, and the film is peeled off. a step of stretching and drying, the step of winding the dried film into a roll, wherein the main solvent is at a temperature ranging from 1 atm (boiling point + 5 ° C) to (boiling point + 20 ° C) The slurry is filtered using a leaf disk filter, and the residual solvent amount is in the range of 2 to 10% by mass, and in the film width direction, the stretching speed specified by the following formula 3 is 250 to 500%/ Extension in the range of min, the elongation rate of the formula 3 (%/min) = [(d1/d2)-1] × 100 (%) / t (in the third formula, the d1-based extended deuterated cellulose film is as described above The wide dimension of the extending direction, the width dimension of the aforementioned extending direction of the deuterated cellulose film before the d2 stretching Elongation time t (min)) required for the. A polarizing plate characterized in that the cellulose ester film according to any one of claims 1 to 8 is followed by a water paste and a polarizer. A polarizing plate characterized in that the cellulose ester film according to any one of claims 1 to 8 is followed by an ultraviolet curing type adhesive and a polarizing mirror.